Research Article Fabrication and Characterization of Dye...
Transcript of Research Article Fabrication and Characterization of Dye...
Research ArticleFabrication and Characterization of Dye-Sensitized Solar Cellsfor Greenhouse Application
Jeum-Jong Kim1 Mangu Kang1 Ock Keum Kwak2 Yong-Jin Yoon3
Kil Sik Min4 and Moo-Jung Chu1
1 IT Materials and Components Laboratory Electronics and Telecommunications Research InstituteDaejeon 305-700 Republic of Korea
2 Sun Moon University Asan-si Chungnam 336-708 Republic of Korea3 Department of Chemistry and Research Institute of Natural Science Graduate School for Molecular Materials and NanochemistryGyeongsang National University Jinju 660-701 Republic of Korea
4Department of Chemistry Education Kyungpook National University Daegu 702-701 Republic of Korea
Correspondence should be addressed to Kil Sik Min minksknuackr and Moo-Jung Chu mjcetrirekr
Received 24 June 2014 Accepted 20 August 2014 Published 8 September 2014
Academic Editor Mohamed Sabry A Abdel-Mottaleb
Copyright copy 2014 Jeum-Jong Kim et alThis is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited
We have developed dye-sensitized solar cells using novel sensitizers with enhanced transmittance of red (625ndash675 nm) and blue(425ndash475 nm) wavebands to control the illumination condition in the greenhouse Novel ruthenium bipyridyl sensitizers withgeneral formulas (Me
3PhN)
4[Ru(dcbpy)
2(NCS)
2] (JJ-7) and (Me
3BnN)
4[Ru(dcbpy)
2(NCS)
2] (JJ-9) have been synthesized and
demonstrated as efficient sensitizers in dye-sensitized solar cells for greenhouse application Under standard AM 15 sunlight thesolar cell of JJ-7 using a liquid-based electrolyte exhibits a short-circuit photocurrent density of 849mAcm2 an open-circuitvoltage of 083V and a fill factor of 071 corresponding to an overall conversion efficiency of 496 on 5 120583m TiO
2film The
transmittance of JJ-7 and JJ-9 shows 620 and 610 at 660 nm and 180 and 150 at 440 nm for cultivation on 5120583m TiO2
film respectively
1 Introduction
A dye-sensitized solar cell (DSSC) is an electrochemicaldevice that uses light-absorbing dye molecules adsorbed onsemiconductor nanoparticles to generate electricity from thesunlight [1ndash5] Current researches on the DSSCs are focusedon the development of cell materials and manufacturingtechniques that give high conversion efficiency low cost andstability [6ndash8]The preparation of dye-sensitized solar cell forgreenhouse is involved in the light manipulation for plantgrowth and energy-saving The light manipulation in green-house is very important to improve the quantity and qualityof the agricultural products The cladding materials [9ndash13]and artificial lights [14ndash20] (LED or high-pressure sodiumlamps) are used to manipulate the light in greenhouse forplant growthUntil now no dye-sensitized solar cells (DSSCs)have been applied in greenhouse for plant growth and energy-saving The most important wavebands for plant growth are
the absorption peaks of chlorophyll located in the red (625ndash675 nm) and blue (425ndash475 nm) regions respectivelyThe redspectrum band is known to be involved in photosynthesisand the blue band is related to the photomorphogenic andthe phototropic responses of plants [21] Therefore dye-sensitized solar cells for greenhouse can be used as technicallyadvanced photoselective coverings that control the environ-mental conditions to optimize the productivity and qualityof farm products and save energy For the plant growth andenergy-saving we have focused on the development of novelsensitizers forDSSCswith enhanced transmittance of red andblue wavebands and high performance This approach is tosynthesize efficient ruthenium sensitizers through a system-atic tuning of the LUMO and HOMO energy levels by intro-ducing a ligand with a high-lying 120587lowast molecular orbital or bystabilizing the metal t
2g orbital Here we report the synthesisof novel ruthenium(II) sensitizers (JJ-7 and JJ-9) for green-house DSSCs and their photovoltaic performance (Figure 1)
Hindawi Publishing CorporationInternational Journal of PhotoenergyVolume 2014 Article ID 376315 7 pageshttpdxdoiorg1011552014376315
2 International Journal of Photoenergy
NN
NCS
NCS
NCS
NCS
NN
Ru Ru
NOOC NOOC
NOOCNOOC
COON COON
COON COON
JJ-7
NN
NN
JJ-9
+minus
+minus
+minus
minus
minus
+
+
minus+minus+
minus+
Figure 1 Molecular structures of JJ-7 and JJ-9
N
N
N
N
RuRuN
N
N
N
MeOH
N3
NCS
NCS
NCS
NCS
HOOC
HOOC
COOH
COOHJJ-7 X = N and R = methyl R1 = phenylJJ-9 X = N and R = methyl R1 = benzyl
(R)3R1X+Ominus
2C
(R)3R1X+Ominus
2C
COminus2X
+R1(R)3
COminus2X
+R1(R)3
(R)3R1XOH
Scheme 1 Schematic diagram for the synthesis of sensitizers JJ-7 and JJ-9
2 Results and Discussion
The synthetic route for the preparation of JJ-7 and JJ-9 isdepicted in Scheme 1 JJ-7 and JJ-9 were prepared by reac-tion of cis-dithiocyanatobis(221015840-bipyridine-441015840-dicarboxy-late)ruthenium(II) sensitizer (N3) dye trimethylphenylam-moniumhydroxide and benzyltrimethylammoniumhydrox-ide respectivelyThe analytical and spectroscopic data of twosensitizers are consistent with the formulated structures
Figures 2 and 3 show plant growth of greenhouse andtheir transmittance spectra using cladding materials Plant 1was grown under solar light and plants 2 3 4 and 5 weregrown using IR cladding material blue cladding materialgreen cladding material and red cladding material respec-tively (Figure 3) The UV-Vis spectrum of red cladding mate-rial displays transmittance band over 570 nm in visible andIR regionThis band is similar to the real solar light spectrumband at red (625ndash675 nm) waveband On the other hand blue
and green cladding materials are not transmitted at red (625ndash675 nm) waveband (Figure 2) We have cultivated lettucein greenhouse covered with cladding materials The lettucegrowth in red cladding material is more superior in quantityand quality to other cladding materials but the lettuce inred cladding material does not appear red color (Figure 3) Inorder to obtain red color of lettuce like the real solar light weneed not only red waveband (625ndash675 nm) but also suitableblue (425ndash475 nm) waveband Therefore we have developedgreenhouse dye-sensitized solar cells using novel sensitizerswith transmittance at both red and blue wavebands
Figure 4 shows the UV-Vis spectra of JJ-7 and JJ-9together with the N719 absorption spectrum as a referenceThe UV-vis spectrum of JJ-7 displays two absorption bandsat 380 and 514 nm which are characteristic of the metal-to-ligand charge transfer (MLCT) bands [22 23]The low energyMLCT band at 514 nm of JJ-7 is 10 nm blue-shifted relative tothat of N719 (524 nm) The band at 440 nm of JJ-7 exhibits
International Journal of Photoenergy 3
(a)
Radi
ance
(Ws
rm
2)
018
016
014
012
01
008
006
004
002
0350 400 450 500 550 600 650 700 750 800 850 900 950 1000
Wavelength (nm)
(b)
Figure 2 Greenhouse of plant growth and transmittance spectra under solar light (out greenhouse dark cyan line) solar light (in greenhousepurple line) IR cladding material (brown line) green cladding material (green line) blue cladding material (blue line) and red claddingmaterial (red line)
1 2 3 4 5
Figure 3 Growth of plant under solar light (1) IR claddingmaterial(2) green cladding material (3) blue cladding material (4) and redcladding material (5)
a molar extinction coefficient of 45 times 103Mminus1 cmminus1 which isslightly lower than that of N719 dye (54times 103Mminus1 cmminus1)Theblue-shift and lower molar extinction coefficient are due toan increase in the energy of the LUMO of the ligand causingthe 120587-120587lowast and d120587-120587lowast transitions to occur at higher energies[24] Also the UV-Vis spectra of JJ-9 display two absorptionbands at 380 and 514 nm and amolar extinction coefficient ofJJ-9 is 47 times 103Mminus1 cmminus1 at 440 nm We also observed thatthe sensitizers JJ-7 and JJ-9 exhibited strong luminescencemaxima at 660ndash700 nm when they were excited with theirMLCT bands in EtOH at 298K
The ultraviolet-visible transmittance spectra of JJ-7 andJJ-9 adsorbed on TiO
2film are shown in Figure 5 together
with the N719 transmittance spectrum as a reference Thetransmittance of JJ-7 and JJ-9 on 5 120583m TiO
2film exhibits
620 and 610 at red (660 nm) and 180 and 150 at
000
005
010
015
020
000
005
010
015
020
Nor
mal
ized
emiss
ion
inte
nsity
Nor
mal
ized
abso
rban
ce
Wavelength (nm)
N719 JJ-7 JJ-9
400 500 600 700 800 900
Figure 4 Absorption and emission spectra of JJ-7 (blue line) JJ-9(orange line) andN719 (red line) in EtOH
blue (440 nm) wavelength for plant production and qualityrespectively which is higher than the corresponding valuefor N719 (480 at red (660 nm) and 70 at blue (440 nm)wavelength) Also the transmittance of JJ-7 and JJ-9 on10 120583mTiO
2film shows 629 and 605 at red (660 nm) and
75 and 63 at blue (440 nm) wavelength for plant produc-tion and quality respectively which is higher than the corre-sponding value for N719 (379 at red (660 nm) and 15 atblue (440 nm) wavelength) The higher transmittance of JJ-7 and JJ-9 compared with N719 is attributable to increased
4 International Journal of Photoenergy
0
10
20
30
40
50
60
70
80
JJ-9
Tran
smitt
ance
()
Wavelength (nm)
N719 JJ-7
300 400 500 600 700 800
(a)
0
10
20
30
40
50
60
70
80
JJ-9Tr
ansm
ittan
ce (
)
Wavelength (nm)
N719 JJ-7
300 400 500 600 700 800
(b)
Figure 5 Transmittance spectra of JJ-7 (blue line) JJ-9 (orange line) andN719 (red line) (a) adsorbed on 5120583m TiO2film and (b) adsorbed
on 10 120583m TiO2film
0
2
4
6
8
10
12
Voltage (V)
JJ-7
N719JJ-9
00 02 04 06 08
Curr
ent d
ensit
y (m
Ac
m2)
(a)
0
2
4
6
8
12
10
16
14
Voltage (V)
JJ-7
N719JJ-9
00 02 04 06 08
Curr
ent d
ensit
y (m
Ac
m2)
(b)
Figure 6 J-V curves of JJ-7 (blue line) JJ-9 (orange line) andN719 (red line) using (a) 5120583m TiO2film and (b) 10 120583m TiO
2film
HOMO-LUMO energy gaps by electron-withdrawing abili-ties in a ligand and low molar extinction coefficient
The J-V curves for the devices based on JJ-7 and JJ-9 are shown and compared with those of N719 in Figure6 Under standard global AM 15 solar conditions when5 120583m TiO
2film was used the JJ-7 and JJ-9 sensitized cell
gave a short circuit photocurrent density (119869sc) of 849 and
940mA cmminus2 an open circuit voltage (119881oc) of 083 and 078Vand a fill factor (FF) of 071 and 069 corresponding to overallconversion efficiency (120578) of 496 and 507 respectively(Table 1) Under the same condition theN719 sensitized cellgave a 119869sc of 1034mA cmminus2 a 119881oc of 082V and a FF of074 corresponding to 120578 of 625 When 10 120583m TiO
2film
was used the JJ-7 and JJ-9 sensitized cell gave short circuit
International Journal of Photoenergy 5
Table 1 Optical redox and DSSC performance parameters of dyes
Dye 120582absanm amp
120582transbnm ()
119864redoxcV 119864
0-0dV 119864LUMO
eV 119869sc (mA cmminus2)(510120583m)
119881oc (V)(510120583m)
FF(510120583m)
120578f ()
(510120583m)
JJ-7 380 514 amp 440 (18)660 (62) 107 208 minus101 8491168 083080 071071 496658
JJ-9 380 514 amp 440 (15)660 (61) 103 206 minus103 9401262 078080 069069 507693
N719 382 524 amp 440 (7)660 (48) 203g (197h) 10341387 082079 074070 625767
aAbsorption spectra were measured in EtOH solution bTransmittance spectra were measured on 1-layer TiO2 film cRedox potential of dyes on TiO2 wasmeasured in CH3CN with 01M (119899-C4H9)4NPF6 as a scan rate of 100mV sminus1 (vs NHE) d1198640-0 values were estimated from the onset of absorption spectrume119864LUMO was calculated by 119864ox minus 1198640-0
fPerformances of DSSCs were measured with 018 cm2 working area Electrolyte 06M DMPImI 005M I2 05M TBPand 01M LiI in acetonitrile gEnergy level calculated by experiment hEnergy level calculated at the B3LYP3-21 G
photocurrent density (119869sc) of 1168 and 1262mA cmminus2 anopen circuit voltage (119881oc) of 080 and 080V and a fill factor(FF) of 071 and 069 corresponding to overall conversionefficiency (120578) of 658 and 693 respectively (Table 1)Under the same condition the N719 sensitized cell gavea 119869sc of 1387mA cmminus2 a 119881oc of 079V and a FF of 070corresponding to 120578 of 767 A slightly lower 119869sc of JJ-7and JJ-9 relative to N719 can be related to the increase oftransmittance and the sparse packing of the JJ-7 and JJ-9 monolayers on the TiO
2electrodes To clarify the above
explanations we measured the amount of dyes adsorbed onTiO2film by desorbing the dyes from the TiO
2surface with
KOH The amounts of three dyes adsorbed on TiO2film
were measured to be 294 times 10minus7 302 times 10minus7 and 376 times10minus7mmol cmminus2 for JJ-7 JJ-9 andN719 respectivelyThe lowadsorption of JJ-7 and JJ-9 can be due to the presence ofbulky protecting groups with electron withdrawing abilitiesof tetra-substituted ammonium groups and the electrostaticrepulsion of negatively charged carboxylic groups
The electrochemical properties of the two sensitizers JJ-7 and JJ-9 were studied by cyclic voltammetry in CH
3CN
with 01M tetrabutylammonium hexafluorophosphate usingTiO2film with adsorbed dyes as working electrode The
oxidation potentials of JJ-7 and JJ-9 adsorbed on TiO2film
show quasi-reversible couples at 107V and 103V versusNHE respectively (Table 1) The RuIIIII oxidation potentialsof JJ-7 and JJ-9 are more positive than that of N719 TheHOMO-LUMO energy band gaps (119864
0-0) of JJ-7 and JJ-9determined from the intersection of absorption and emissionspectra are 208 and 206 eV respectivelymore increased thanthat of N719 (185 eV for experimental calculation [25] and197 eV for theoretical calculation by B3LYP3-21 G [26 27])This reflects the increased electron withdrawing properties ofligand with tetra-substituted ammonium groups The reduc-tion potentials of two dyes calculated from the oxidationpotentials and the 119864
0-0 determined from the intersection ofabsorption and emission spectra are minus101 V for JJ-7 andminus103V for JJ-9 versus NHE A negative shift in the reductionpotential of JJ-7 and JJ-9 compared to N719 is attributableto electron-withdrawing abilities in ligands and increasedHOMO-LUMO energy band gaps
Figure 7 shows intensity of radiation in dye-sensitizedsolar cell using JJ-7 and N719 sensitizers After making box
we have measured the intensity of radiation as in Figure 7The radiation intensities for JJ-7 sensitizers with both 5 and10 120583m TiO
2thickness films are much higher than that of
N719 sensitizer with 5120583m TiO2thickness film This result
demonstrates that the novel JJ-7 sensitizer is very effectivein greenhouse dye-sensitized solar cell to grow plant On theother hand the existingN719 sensitizer is not useful becauseof the low quantity of lightThe different light quantity mightbe caused by the differentmolecular structure of the dyesThehigh quantity of light in JJ-7 compared to that of N719 maybe due to the defects of adsorption of JJ-7 sensitizer on theTiO2electrodes
In conclusion two novel ruthenium bipyridyl sensitiz-ers have been synthesized and characterized A solar-to-electricity conversion efficiency of 496 (for 5120583mTiO
2film)
and 658 (for 10 120583m TiO2film) for JJ-7 is comparable to
625 (for 5120583m TiO2film) and 767 (for 10 120583m TiO
2film)
for the N719-sensitized solar cell The high transmittance(62 at 660 nm and 18 at 440 nm) of JJ-7 is attributed toits low absorption extinction coefficient ofMLCT band in thevisible region and blue-shift by an increased HOMO-LUMOenergy band gap We believe that the development of highlyefficient sensitizers for greenhouse dye-sensitized solar cellis possible through meticulously molecular engineering andwork on these is now in progress
3 Experimental Section
31 Fabrication of Dye-Sensitized Solar Cells Fluorine-dopedtin oxide (FTO) glass plates (Pilkington TEC Glass-TEC8 solar 23mm thickness) were cleaned in a detergentsolution using an ultrasonic bath for 30min and then rinsedwith water and ethanol Then the plates were immersed in40mM TiCl
4(aqueous) at 70∘C for 30min and washed with
water and ethanol A transparent nanocrystalline layer wasprepared on the FTO glass plates by using a doctor bladeprinting TiO
2paste (Solaronix Ti-Nanoxide TSP) which
was then dried for 2 h at 25∘C The TiO2electrodes were
gradually heated under an air flow at 325∘C for 5min at375∘C for 5min at 450∘C for 15min and at 500∘C for 15minThe thickness of the transparent layer was measured by usingan Alpha-step 250 surface profilometer (Tencor InstrumentsSan Jose CA) The resulting film was composed of a 5
6 International Journal of Photoenergy
200
400
600
800
1000
1200
1400
1600
1800
2000
2200
Time
Out10 times 10 N7195120583m
10 times 10 JJ-7 10120583m10 times 10 JJ-7 5120583m
8 10 12 14 16 18
(120583m
olm
2s)
Figure 7 The intensity of radiation for JJ-7 (5120583m black line) JJ-7 (10120583m red line) N719 (5120583m green line) and out (blue line) andgreenhouse test-bed of dye-sensitized solar cell using new sensitizer (JJ-7)
and 10 120583m thick transparent layer The TiO2electrodes were
treated again with TiCl4at 70∘C for 30min and sintered at
500∘C for 30minThen they were immersed in JJ-7 and JJ-9(03mM in ethanol) solutions and kept at room temperaturefor 24 h FTO plates for the counter electrodes were cleanedin an ultrasonic bath in H
2O acetone and 01M aqueous
HCl subsequently The counter electrodes were preparedby placing a drop of an H
2PtCl6solution (2mg Pt in 1mL
ethanol) on an FTO plate and heating it (at 400∘C) for15minThe dye adsorbed TiO
2electrodes and the Pt counter
electrodes were assembled into a sealed sandwich-type cellby heating at 80∘C using a hot-melt ionomer film (Surlyn)as a spacer between the electrodes A drop of the electrolyteconsisting of 06M 12-dimethyl-3-propylimidazolium iodide(DMPII) 005M I
2 01M LiI and 05M tert-butylpyridine
in acetonitrile was placed in the drilled hole of the counterelectrode and was driven into the cell via vacuum backfillingFinally the hole was sealed using additional Surlyn and acover glass (01mm thickness)
32 Typical Procedures and Analytical Data
JJ-7 Complex A mixture of N3 (100mg 0141mmol)and trimethylphenylammonium hydroxide (434mg0708mmol) in MeOH (2mL) was stirred at room temp-erature for 2 h The pure product JJ-7 was obtained bySephadex LH-20 column with methanol as eluent Yield97 1H NMR (CD
3OD) 943 (d 2H 119869 = 57Hz) 890
(s 2H) 874 (s 2H) 813 (dd 2H 119869 = 57Hz) 793 (m6H) 763ndash750 (m 18H 370 (s 36H) Anal calcd forC62H68N10O8RuS2 C 5974 H 550 Found C 5977
H548
JJ-9 Complex A mixture of N3 (100mg 0141mmol)and benzyltrimethylammonium hydroxide (296mg
0708mmol) in MeOH (2mL) was stirred at room tempera-ture for 2 hThe pure product JJ-9 was obtained by SephadexLH-20 column with methanol as eluent Yield 94 1HNMR (CD
3OD) 941 (d 2H 119869 = 58Hz) 891 (s 2H) 875
(s 2H) 810 (dd 2H 119869 = 58Hz) 754 (m 24H) 455 (s 8H)312 (s 36H) Anal calcd for C
66H76N10O8RuS2 C 6086 H
588 Found C 6078 H 594
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgment
This work was supported by Electronics and Telecommuni-cations Research Institute (ETRI)
References
[1] B OrsquoRegan and M Gratzel ldquoA low-cost high-efficiency solarcell based on dye-sensitized colloidal TiO
2filmsrdquo Nature vol
353 pp 737ndash740 1991[2] K Hara H Sugihara Y Tachibana et al ldquoDye-sensitized nano-
crystalline TiO2solar cells based on ruthenium(II) phenanthro-
line complex photosensitizersrdquo Langmuir vol 17 no 19 pp5992ndash5999 2001
[3] T Horiuchi H Miura K Sumioka and S Uchida ldquoHigh effi-ciency of dye-sensitized solar cells based onmetal-free indolinedyesrdquo Journal of the American Chemical Society vol 126 no 39pp 12218ndash12219 2004
[4] S A Haque S Handa K Peter E PalomaresMThelakkat andJ RDurrant ldquoSupermolecular control of charge transfer in dye-sensitized Nanocrystalline TiO
2films towards a quantitative
International Journal of Photoenergy 7
structure-function relationshiprdquo Angewandte Chemie Interna-tional Edition vol 44 no 35 pp 5740ndash5744 2005
[5] DKuang PWalter FNuesch et al ldquoCo-sensitization of organicdyes for efficient ionic liquid electrolyte-based dye-sensitizedsolar cellsrdquo Langmuir vol 23 no 22 pp 10906ndash10909 2007
[6] T Renouard R A Fallahpour M K Nazeeruddin et al ldquoNovelruthenium sensitizers containing functionalized hybrid tetra-dentate ligands Synthesis characterization and INDOS anal-ysisrdquo Inorganic Chemistry vol 41 no 2 pp 367ndash378 2002
[7] M K Nazeeruddin P Pechy T Renouard et al ldquoEngineeringof efficient panchromatic sensitizers for nanocrystalline TiO
2-
based solar cellsrdquo Journal of the American Chemical Society vol123 no 8 pp 1613ndash1624 2001
[8] K Chen Y-H Hong Y Chi W-H Liu B-S Chen and P-TChou ldquoStrategic design and synthesis of novel tridentate bipyri-dine pyrazolate coupled Ru(II) complexes to achieve superiorsolar conversion efficiencyrdquo Journal of Materials Chemistry vol19 no 30 pp 5329ndash5335 2009
[9] S Pearson A E Wheldon and P Hadley ldquoRadiation transmis-sion and fluorescence of nine greenhouse cladding materialsrdquoJournal of Agricultural Engineering Research vol 62 no 1 pp61ndash70 1995
[10] C Kittas and A Baille ldquoDetermination of the spectral proper-ties of several greenhouse covermaterials and evaluation of spe-cific parameters related to plant responserdquo Journal of Agricul-tural Engineering Research vol 71 no 2 pp 193ndash202 1998
[11] S Tazawa ldquoEffects of various radiant sources on plant growth(part 1)rdquo Japan Agricultural Research Quarterly vol 33 p 1631999
[12] S Hemming E van Os A Dieleman et al ldquoPossibilities ofincreasing production and quality of strawberry fruits andseveral flowers by new blue fluorescent greenhouse filmsrdquo ActaHorticulturae vol 691 pp 225ndash232 2005
[13] E Espı A Salmeron A Fontecha Y Garcıa and A I RealldquoPlastic films for agricultural applicationsrdquo Journal of PlasticFilm and Sheeting vol 22 no 2 pp 85ndash102 2006
[14] W Fang and R C JaoTransplant Production in the 21st Century2000
[15] RMoe S O Grimstad andH R Gisleroslashd ldquoThe use of artificiallight in year round production of greenhouse crops in NorwayrdquoActa Horticulturae vol 711 pp 35ndash42 2006
[16] H-H Kim R M Wheeler J C Sager N C Yorio and GD Goins ldquoLight-emitting diodes as an illumination source forplants a review of research at Kennedy Space Centerrdquo Habita-tion vol 10 no 2 pp 71ndash78 2005
[17] E Ono and H Watanabe ldquoPlant factories blossomrdquo ResourceEngineering amp Technology for Sustainable World vol 13 no 2pp 13ndash14 2006
[18] R C Morrow ldquoLED lighting in horticulturerdquo HortScience vol43 no 7 pp 1947ndash1950 2008
[19] G D Massa H H Kim R M Wheeler and C A MitchellldquoPlant productivity in response to LED lightingrdquo HortSciencevol 43 no 7 pp 1951ndash1956 2008
[20] N Yeh and J-P Chung ldquoHigh-brightness LEDsmdashenergy effi-cient lighting sources and their potential in indoor plant culti-vationrdquo Renewable and Sustainable Energy Reviews vol 13 no8 pp 2175ndash2180 2009
[21] I Vanninen D M Pinto A I Nissinen N S Johansen and LShipp ldquoIn the light of new greenhouse technologies 1 Plant-mediated effects of artificial lighting on arthropods and tritro-phic interactionsrdquo Annals of Applied Biology vol 157 no 3 pp393ndash414 2010
[22] T Bessho E Yoneda J-H Yum et al ldquoNew paradigm inmolecular engineering of sensitizers for solar cell applicationsrdquoJournal of the American Chemical Society vol 131 no 16 pp5930ndash5934 2009
[23] F Mater T H Ghaddar K Walley T DosSantos J R Durrantand B OrsquoRegan ldquoA new ruthenium polypyridyl dye TG6whose performance in dye-sensitized solar cells is surprisinglyclose to that of N719 the lsquodye to beatrsquo for 17 years rdquo Journal ofMaterials Chemistry vol 18 pp 4246ndash4253 2008
[24] M K Nazeeruddin R Humphry-Baker P Liska and MGratzel ldquoInvestigation of sensitizer adsorption and the influ-ence of protons on current and voltage of a dye-sensitized nano-crystalline TiO
2solar cellrdquoThe Journal of Physical Chemistry B
vol 107 no 34 pp 8981ndash8987 2003[25] Y Lee S R Jang R Vittal andK J Kim ldquoDinuclear Ru(II) dyes
for improved performance of dye-sensitized TiO2solar cellsrdquo
New Journal of Chemistry vol 31 no 12 pp 2120ndash2126 2007[26] M K Nazeeruddin F De Angelis S Fantacci et al ldquoCom-
bined experimental and DFT-TDDFT computational study ofphotoelectrochemical cell ruthenium sensitizersrdquo Journal of theAmerican Chemical Society vol 127 no 48 pp 16835ndash168472005
[27] M K Nazeeruddin T Bessho L Cevey et al ldquoA high molarextinction coefficient charge transfer sensitizer and its applica-tion in dye-sensitized solar cellrdquo Journal of Photochemistry andPhotobiology A Chemistry vol 185 no 2-3 pp 331ndash337 2007
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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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International Journal ofPhotoenergy
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CatalystsJournal of
2 International Journal of Photoenergy
NN
NCS
NCS
NCS
NCS
NN
Ru Ru
NOOC NOOC
NOOCNOOC
COON COON
COON COON
JJ-7
NN
NN
JJ-9
+minus
+minus
+minus
minus
minus
+
+
minus+minus+
minus+
Figure 1 Molecular structures of JJ-7 and JJ-9
N
N
N
N
RuRuN
N
N
N
MeOH
N3
NCS
NCS
NCS
NCS
HOOC
HOOC
COOH
COOHJJ-7 X = N and R = methyl R1 = phenylJJ-9 X = N and R = methyl R1 = benzyl
(R)3R1X+Ominus
2C
(R)3R1X+Ominus
2C
COminus2X
+R1(R)3
COminus2X
+R1(R)3
(R)3R1XOH
Scheme 1 Schematic diagram for the synthesis of sensitizers JJ-7 and JJ-9
2 Results and Discussion
The synthetic route for the preparation of JJ-7 and JJ-9 isdepicted in Scheme 1 JJ-7 and JJ-9 were prepared by reac-tion of cis-dithiocyanatobis(221015840-bipyridine-441015840-dicarboxy-late)ruthenium(II) sensitizer (N3) dye trimethylphenylam-moniumhydroxide and benzyltrimethylammoniumhydrox-ide respectivelyThe analytical and spectroscopic data of twosensitizers are consistent with the formulated structures
Figures 2 and 3 show plant growth of greenhouse andtheir transmittance spectra using cladding materials Plant 1was grown under solar light and plants 2 3 4 and 5 weregrown using IR cladding material blue cladding materialgreen cladding material and red cladding material respec-tively (Figure 3) The UV-Vis spectrum of red cladding mate-rial displays transmittance band over 570 nm in visible andIR regionThis band is similar to the real solar light spectrumband at red (625ndash675 nm) waveband On the other hand blue
and green cladding materials are not transmitted at red (625ndash675 nm) waveband (Figure 2) We have cultivated lettucein greenhouse covered with cladding materials The lettucegrowth in red cladding material is more superior in quantityand quality to other cladding materials but the lettuce inred cladding material does not appear red color (Figure 3) Inorder to obtain red color of lettuce like the real solar light weneed not only red waveband (625ndash675 nm) but also suitableblue (425ndash475 nm) waveband Therefore we have developedgreenhouse dye-sensitized solar cells using novel sensitizerswith transmittance at both red and blue wavebands
Figure 4 shows the UV-Vis spectra of JJ-7 and JJ-9together with the N719 absorption spectrum as a referenceThe UV-vis spectrum of JJ-7 displays two absorption bandsat 380 and 514 nm which are characteristic of the metal-to-ligand charge transfer (MLCT) bands [22 23]The low energyMLCT band at 514 nm of JJ-7 is 10 nm blue-shifted relative tothat of N719 (524 nm) The band at 440 nm of JJ-7 exhibits
International Journal of Photoenergy 3
(a)
Radi
ance
(Ws
rm
2)
018
016
014
012
01
008
006
004
002
0350 400 450 500 550 600 650 700 750 800 850 900 950 1000
Wavelength (nm)
(b)
Figure 2 Greenhouse of plant growth and transmittance spectra under solar light (out greenhouse dark cyan line) solar light (in greenhousepurple line) IR cladding material (brown line) green cladding material (green line) blue cladding material (blue line) and red claddingmaterial (red line)
1 2 3 4 5
Figure 3 Growth of plant under solar light (1) IR claddingmaterial(2) green cladding material (3) blue cladding material (4) and redcladding material (5)
a molar extinction coefficient of 45 times 103Mminus1 cmminus1 which isslightly lower than that of N719 dye (54times 103Mminus1 cmminus1)Theblue-shift and lower molar extinction coefficient are due toan increase in the energy of the LUMO of the ligand causingthe 120587-120587lowast and d120587-120587lowast transitions to occur at higher energies[24] Also the UV-Vis spectra of JJ-9 display two absorptionbands at 380 and 514 nm and amolar extinction coefficient ofJJ-9 is 47 times 103Mminus1 cmminus1 at 440 nm We also observed thatthe sensitizers JJ-7 and JJ-9 exhibited strong luminescencemaxima at 660ndash700 nm when they were excited with theirMLCT bands in EtOH at 298K
The ultraviolet-visible transmittance spectra of JJ-7 andJJ-9 adsorbed on TiO
2film are shown in Figure 5 together
with the N719 transmittance spectrum as a reference Thetransmittance of JJ-7 and JJ-9 on 5 120583m TiO
2film exhibits
620 and 610 at red (660 nm) and 180 and 150 at
000
005
010
015
020
000
005
010
015
020
Nor
mal
ized
emiss
ion
inte
nsity
Nor
mal
ized
abso
rban
ce
Wavelength (nm)
N719 JJ-7 JJ-9
400 500 600 700 800 900
Figure 4 Absorption and emission spectra of JJ-7 (blue line) JJ-9(orange line) andN719 (red line) in EtOH
blue (440 nm) wavelength for plant production and qualityrespectively which is higher than the corresponding valuefor N719 (480 at red (660 nm) and 70 at blue (440 nm)wavelength) Also the transmittance of JJ-7 and JJ-9 on10 120583mTiO
2film shows 629 and 605 at red (660 nm) and
75 and 63 at blue (440 nm) wavelength for plant produc-tion and quality respectively which is higher than the corre-sponding value for N719 (379 at red (660 nm) and 15 atblue (440 nm) wavelength) The higher transmittance of JJ-7 and JJ-9 compared with N719 is attributable to increased
4 International Journal of Photoenergy
0
10
20
30
40
50
60
70
80
JJ-9
Tran
smitt
ance
()
Wavelength (nm)
N719 JJ-7
300 400 500 600 700 800
(a)
0
10
20
30
40
50
60
70
80
JJ-9Tr
ansm
ittan
ce (
)
Wavelength (nm)
N719 JJ-7
300 400 500 600 700 800
(b)
Figure 5 Transmittance spectra of JJ-7 (blue line) JJ-9 (orange line) andN719 (red line) (a) adsorbed on 5120583m TiO2film and (b) adsorbed
on 10 120583m TiO2film
0
2
4
6
8
10
12
Voltage (V)
JJ-7
N719JJ-9
00 02 04 06 08
Curr
ent d
ensit
y (m
Ac
m2)
(a)
0
2
4
6
8
12
10
16
14
Voltage (V)
JJ-7
N719JJ-9
00 02 04 06 08
Curr
ent d
ensit
y (m
Ac
m2)
(b)
Figure 6 J-V curves of JJ-7 (blue line) JJ-9 (orange line) andN719 (red line) using (a) 5120583m TiO2film and (b) 10 120583m TiO
2film
HOMO-LUMO energy gaps by electron-withdrawing abili-ties in a ligand and low molar extinction coefficient
The J-V curves for the devices based on JJ-7 and JJ-9 are shown and compared with those of N719 in Figure6 Under standard global AM 15 solar conditions when5 120583m TiO
2film was used the JJ-7 and JJ-9 sensitized cell
gave a short circuit photocurrent density (119869sc) of 849 and
940mA cmminus2 an open circuit voltage (119881oc) of 083 and 078Vand a fill factor (FF) of 071 and 069 corresponding to overallconversion efficiency (120578) of 496 and 507 respectively(Table 1) Under the same condition theN719 sensitized cellgave a 119869sc of 1034mA cmminus2 a 119881oc of 082V and a FF of074 corresponding to 120578 of 625 When 10 120583m TiO
2film
was used the JJ-7 and JJ-9 sensitized cell gave short circuit
International Journal of Photoenergy 5
Table 1 Optical redox and DSSC performance parameters of dyes
Dye 120582absanm amp
120582transbnm ()
119864redoxcV 119864
0-0dV 119864LUMO
eV 119869sc (mA cmminus2)(510120583m)
119881oc (V)(510120583m)
FF(510120583m)
120578f ()
(510120583m)
JJ-7 380 514 amp 440 (18)660 (62) 107 208 minus101 8491168 083080 071071 496658
JJ-9 380 514 amp 440 (15)660 (61) 103 206 minus103 9401262 078080 069069 507693
N719 382 524 amp 440 (7)660 (48) 203g (197h) 10341387 082079 074070 625767
aAbsorption spectra were measured in EtOH solution bTransmittance spectra were measured on 1-layer TiO2 film cRedox potential of dyes on TiO2 wasmeasured in CH3CN with 01M (119899-C4H9)4NPF6 as a scan rate of 100mV sminus1 (vs NHE) d1198640-0 values were estimated from the onset of absorption spectrume119864LUMO was calculated by 119864ox minus 1198640-0
fPerformances of DSSCs were measured with 018 cm2 working area Electrolyte 06M DMPImI 005M I2 05M TBPand 01M LiI in acetonitrile gEnergy level calculated by experiment hEnergy level calculated at the B3LYP3-21 G
photocurrent density (119869sc) of 1168 and 1262mA cmminus2 anopen circuit voltage (119881oc) of 080 and 080V and a fill factor(FF) of 071 and 069 corresponding to overall conversionefficiency (120578) of 658 and 693 respectively (Table 1)Under the same condition the N719 sensitized cell gavea 119869sc of 1387mA cmminus2 a 119881oc of 079V and a FF of 070corresponding to 120578 of 767 A slightly lower 119869sc of JJ-7and JJ-9 relative to N719 can be related to the increase oftransmittance and the sparse packing of the JJ-7 and JJ-9 monolayers on the TiO
2electrodes To clarify the above
explanations we measured the amount of dyes adsorbed onTiO2film by desorbing the dyes from the TiO
2surface with
KOH The amounts of three dyes adsorbed on TiO2film
were measured to be 294 times 10minus7 302 times 10minus7 and 376 times10minus7mmol cmminus2 for JJ-7 JJ-9 andN719 respectivelyThe lowadsorption of JJ-7 and JJ-9 can be due to the presence ofbulky protecting groups with electron withdrawing abilitiesof tetra-substituted ammonium groups and the electrostaticrepulsion of negatively charged carboxylic groups
The electrochemical properties of the two sensitizers JJ-7 and JJ-9 were studied by cyclic voltammetry in CH
3CN
with 01M tetrabutylammonium hexafluorophosphate usingTiO2film with adsorbed dyes as working electrode The
oxidation potentials of JJ-7 and JJ-9 adsorbed on TiO2film
show quasi-reversible couples at 107V and 103V versusNHE respectively (Table 1) The RuIIIII oxidation potentialsof JJ-7 and JJ-9 are more positive than that of N719 TheHOMO-LUMO energy band gaps (119864
0-0) of JJ-7 and JJ-9determined from the intersection of absorption and emissionspectra are 208 and 206 eV respectivelymore increased thanthat of N719 (185 eV for experimental calculation [25] and197 eV for theoretical calculation by B3LYP3-21 G [26 27])This reflects the increased electron withdrawing properties ofligand with tetra-substituted ammonium groups The reduc-tion potentials of two dyes calculated from the oxidationpotentials and the 119864
0-0 determined from the intersection ofabsorption and emission spectra are minus101 V for JJ-7 andminus103V for JJ-9 versus NHE A negative shift in the reductionpotential of JJ-7 and JJ-9 compared to N719 is attributableto electron-withdrawing abilities in ligands and increasedHOMO-LUMO energy band gaps
Figure 7 shows intensity of radiation in dye-sensitizedsolar cell using JJ-7 and N719 sensitizers After making box
we have measured the intensity of radiation as in Figure 7The radiation intensities for JJ-7 sensitizers with both 5 and10 120583m TiO
2thickness films are much higher than that of
N719 sensitizer with 5120583m TiO2thickness film This result
demonstrates that the novel JJ-7 sensitizer is very effectivein greenhouse dye-sensitized solar cell to grow plant On theother hand the existingN719 sensitizer is not useful becauseof the low quantity of lightThe different light quantity mightbe caused by the differentmolecular structure of the dyesThehigh quantity of light in JJ-7 compared to that of N719 maybe due to the defects of adsorption of JJ-7 sensitizer on theTiO2electrodes
In conclusion two novel ruthenium bipyridyl sensitiz-ers have been synthesized and characterized A solar-to-electricity conversion efficiency of 496 (for 5120583mTiO
2film)
and 658 (for 10 120583m TiO2film) for JJ-7 is comparable to
625 (for 5120583m TiO2film) and 767 (for 10 120583m TiO
2film)
for the N719-sensitized solar cell The high transmittance(62 at 660 nm and 18 at 440 nm) of JJ-7 is attributed toits low absorption extinction coefficient ofMLCT band in thevisible region and blue-shift by an increased HOMO-LUMOenergy band gap We believe that the development of highlyefficient sensitizers for greenhouse dye-sensitized solar cellis possible through meticulously molecular engineering andwork on these is now in progress
3 Experimental Section
31 Fabrication of Dye-Sensitized Solar Cells Fluorine-dopedtin oxide (FTO) glass plates (Pilkington TEC Glass-TEC8 solar 23mm thickness) were cleaned in a detergentsolution using an ultrasonic bath for 30min and then rinsedwith water and ethanol Then the plates were immersed in40mM TiCl
4(aqueous) at 70∘C for 30min and washed with
water and ethanol A transparent nanocrystalline layer wasprepared on the FTO glass plates by using a doctor bladeprinting TiO
2paste (Solaronix Ti-Nanoxide TSP) which
was then dried for 2 h at 25∘C The TiO2electrodes were
gradually heated under an air flow at 325∘C for 5min at375∘C for 5min at 450∘C for 15min and at 500∘C for 15minThe thickness of the transparent layer was measured by usingan Alpha-step 250 surface profilometer (Tencor InstrumentsSan Jose CA) The resulting film was composed of a 5
6 International Journal of Photoenergy
200
400
600
800
1000
1200
1400
1600
1800
2000
2200
Time
Out10 times 10 N7195120583m
10 times 10 JJ-7 10120583m10 times 10 JJ-7 5120583m
8 10 12 14 16 18
(120583m
olm
2s)
Figure 7 The intensity of radiation for JJ-7 (5120583m black line) JJ-7 (10120583m red line) N719 (5120583m green line) and out (blue line) andgreenhouse test-bed of dye-sensitized solar cell using new sensitizer (JJ-7)
and 10 120583m thick transparent layer The TiO2electrodes were
treated again with TiCl4at 70∘C for 30min and sintered at
500∘C for 30minThen they were immersed in JJ-7 and JJ-9(03mM in ethanol) solutions and kept at room temperaturefor 24 h FTO plates for the counter electrodes were cleanedin an ultrasonic bath in H
2O acetone and 01M aqueous
HCl subsequently The counter electrodes were preparedby placing a drop of an H
2PtCl6solution (2mg Pt in 1mL
ethanol) on an FTO plate and heating it (at 400∘C) for15minThe dye adsorbed TiO
2electrodes and the Pt counter
electrodes were assembled into a sealed sandwich-type cellby heating at 80∘C using a hot-melt ionomer film (Surlyn)as a spacer between the electrodes A drop of the electrolyteconsisting of 06M 12-dimethyl-3-propylimidazolium iodide(DMPII) 005M I
2 01M LiI and 05M tert-butylpyridine
in acetonitrile was placed in the drilled hole of the counterelectrode and was driven into the cell via vacuum backfillingFinally the hole was sealed using additional Surlyn and acover glass (01mm thickness)
32 Typical Procedures and Analytical Data
JJ-7 Complex A mixture of N3 (100mg 0141mmol)and trimethylphenylammonium hydroxide (434mg0708mmol) in MeOH (2mL) was stirred at room temp-erature for 2 h The pure product JJ-7 was obtained bySephadex LH-20 column with methanol as eluent Yield97 1H NMR (CD
3OD) 943 (d 2H 119869 = 57Hz) 890
(s 2H) 874 (s 2H) 813 (dd 2H 119869 = 57Hz) 793 (m6H) 763ndash750 (m 18H 370 (s 36H) Anal calcd forC62H68N10O8RuS2 C 5974 H 550 Found C 5977
H548
JJ-9 Complex A mixture of N3 (100mg 0141mmol)and benzyltrimethylammonium hydroxide (296mg
0708mmol) in MeOH (2mL) was stirred at room tempera-ture for 2 hThe pure product JJ-9 was obtained by SephadexLH-20 column with methanol as eluent Yield 94 1HNMR (CD
3OD) 941 (d 2H 119869 = 58Hz) 891 (s 2H) 875
(s 2H) 810 (dd 2H 119869 = 58Hz) 754 (m 24H) 455 (s 8H)312 (s 36H) Anal calcd for C
66H76N10O8RuS2 C 6086 H
588 Found C 6078 H 594
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgment
This work was supported by Electronics and Telecommuni-cations Research Institute (ETRI)
References
[1] B OrsquoRegan and M Gratzel ldquoA low-cost high-efficiency solarcell based on dye-sensitized colloidal TiO
2filmsrdquo Nature vol
353 pp 737ndash740 1991[2] K Hara H Sugihara Y Tachibana et al ldquoDye-sensitized nano-
crystalline TiO2solar cells based on ruthenium(II) phenanthro-
line complex photosensitizersrdquo Langmuir vol 17 no 19 pp5992ndash5999 2001
[3] T Horiuchi H Miura K Sumioka and S Uchida ldquoHigh effi-ciency of dye-sensitized solar cells based onmetal-free indolinedyesrdquo Journal of the American Chemical Society vol 126 no 39pp 12218ndash12219 2004
[4] S A Haque S Handa K Peter E PalomaresMThelakkat andJ RDurrant ldquoSupermolecular control of charge transfer in dye-sensitized Nanocrystalline TiO
2films towards a quantitative
International Journal of Photoenergy 7
structure-function relationshiprdquo Angewandte Chemie Interna-tional Edition vol 44 no 35 pp 5740ndash5744 2005
[5] DKuang PWalter FNuesch et al ldquoCo-sensitization of organicdyes for efficient ionic liquid electrolyte-based dye-sensitizedsolar cellsrdquo Langmuir vol 23 no 22 pp 10906ndash10909 2007
[6] T Renouard R A Fallahpour M K Nazeeruddin et al ldquoNovelruthenium sensitizers containing functionalized hybrid tetra-dentate ligands Synthesis characterization and INDOS anal-ysisrdquo Inorganic Chemistry vol 41 no 2 pp 367ndash378 2002
[7] M K Nazeeruddin P Pechy T Renouard et al ldquoEngineeringof efficient panchromatic sensitizers for nanocrystalline TiO
2-
based solar cellsrdquo Journal of the American Chemical Society vol123 no 8 pp 1613ndash1624 2001
[8] K Chen Y-H Hong Y Chi W-H Liu B-S Chen and P-TChou ldquoStrategic design and synthesis of novel tridentate bipyri-dine pyrazolate coupled Ru(II) complexes to achieve superiorsolar conversion efficiencyrdquo Journal of Materials Chemistry vol19 no 30 pp 5329ndash5335 2009
[9] S Pearson A E Wheldon and P Hadley ldquoRadiation transmis-sion and fluorescence of nine greenhouse cladding materialsrdquoJournal of Agricultural Engineering Research vol 62 no 1 pp61ndash70 1995
[10] C Kittas and A Baille ldquoDetermination of the spectral proper-ties of several greenhouse covermaterials and evaluation of spe-cific parameters related to plant responserdquo Journal of Agricul-tural Engineering Research vol 71 no 2 pp 193ndash202 1998
[11] S Tazawa ldquoEffects of various radiant sources on plant growth(part 1)rdquo Japan Agricultural Research Quarterly vol 33 p 1631999
[12] S Hemming E van Os A Dieleman et al ldquoPossibilities ofincreasing production and quality of strawberry fruits andseveral flowers by new blue fluorescent greenhouse filmsrdquo ActaHorticulturae vol 691 pp 225ndash232 2005
[13] E Espı A Salmeron A Fontecha Y Garcıa and A I RealldquoPlastic films for agricultural applicationsrdquo Journal of PlasticFilm and Sheeting vol 22 no 2 pp 85ndash102 2006
[14] W Fang and R C JaoTransplant Production in the 21st Century2000
[15] RMoe S O Grimstad andH R Gisleroslashd ldquoThe use of artificiallight in year round production of greenhouse crops in NorwayrdquoActa Horticulturae vol 711 pp 35ndash42 2006
[16] H-H Kim R M Wheeler J C Sager N C Yorio and GD Goins ldquoLight-emitting diodes as an illumination source forplants a review of research at Kennedy Space Centerrdquo Habita-tion vol 10 no 2 pp 71ndash78 2005
[17] E Ono and H Watanabe ldquoPlant factories blossomrdquo ResourceEngineering amp Technology for Sustainable World vol 13 no 2pp 13ndash14 2006
[18] R C Morrow ldquoLED lighting in horticulturerdquo HortScience vol43 no 7 pp 1947ndash1950 2008
[19] G D Massa H H Kim R M Wheeler and C A MitchellldquoPlant productivity in response to LED lightingrdquo HortSciencevol 43 no 7 pp 1951ndash1956 2008
[20] N Yeh and J-P Chung ldquoHigh-brightness LEDsmdashenergy effi-cient lighting sources and their potential in indoor plant culti-vationrdquo Renewable and Sustainable Energy Reviews vol 13 no8 pp 2175ndash2180 2009
[21] I Vanninen D M Pinto A I Nissinen N S Johansen and LShipp ldquoIn the light of new greenhouse technologies 1 Plant-mediated effects of artificial lighting on arthropods and tritro-phic interactionsrdquo Annals of Applied Biology vol 157 no 3 pp393ndash414 2010
[22] T Bessho E Yoneda J-H Yum et al ldquoNew paradigm inmolecular engineering of sensitizers for solar cell applicationsrdquoJournal of the American Chemical Society vol 131 no 16 pp5930ndash5934 2009
[23] F Mater T H Ghaddar K Walley T DosSantos J R Durrantand B OrsquoRegan ldquoA new ruthenium polypyridyl dye TG6whose performance in dye-sensitized solar cells is surprisinglyclose to that of N719 the lsquodye to beatrsquo for 17 years rdquo Journal ofMaterials Chemistry vol 18 pp 4246ndash4253 2008
[24] M K Nazeeruddin R Humphry-Baker P Liska and MGratzel ldquoInvestigation of sensitizer adsorption and the influ-ence of protons on current and voltage of a dye-sensitized nano-crystalline TiO
2solar cellrdquoThe Journal of Physical Chemistry B
vol 107 no 34 pp 8981ndash8987 2003[25] Y Lee S R Jang R Vittal andK J Kim ldquoDinuclear Ru(II) dyes
for improved performance of dye-sensitized TiO2solar cellsrdquo
New Journal of Chemistry vol 31 no 12 pp 2120ndash2126 2007[26] M K Nazeeruddin F De Angelis S Fantacci et al ldquoCom-
bined experimental and DFT-TDDFT computational study ofphotoelectrochemical cell ruthenium sensitizersrdquo Journal of theAmerican Chemical Society vol 127 no 48 pp 16835ndash168472005
[27] M K Nazeeruddin T Bessho L Cevey et al ldquoA high molarextinction coefficient charge transfer sensitizer and its applica-tion in dye-sensitized solar cellrdquo Journal of Photochemistry andPhotobiology A Chemistry vol 185 no 2-3 pp 331ndash337 2007
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Inorganic ChemistryInternational Journal of
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
International Journal ofPhotoenergy
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Carbohydrate Chemistry
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Advances in
Physical Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom
Analytical Methods in Chemistry
Journal of
Volume 2014
Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
SpectroscopyInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Medicinal ChemistryInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chromatography Research International
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Applied ChemistryJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Theoretical ChemistryJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Spectroscopy
Analytical ChemistryInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Quantum Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Organic Chemistry International
ElectrochemistryInternational Journal of
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CatalystsJournal of
International Journal of Photoenergy 3
(a)
Radi
ance
(Ws
rm
2)
018
016
014
012
01
008
006
004
002
0350 400 450 500 550 600 650 700 750 800 850 900 950 1000
Wavelength (nm)
(b)
Figure 2 Greenhouse of plant growth and transmittance spectra under solar light (out greenhouse dark cyan line) solar light (in greenhousepurple line) IR cladding material (brown line) green cladding material (green line) blue cladding material (blue line) and red claddingmaterial (red line)
1 2 3 4 5
Figure 3 Growth of plant under solar light (1) IR claddingmaterial(2) green cladding material (3) blue cladding material (4) and redcladding material (5)
a molar extinction coefficient of 45 times 103Mminus1 cmminus1 which isslightly lower than that of N719 dye (54times 103Mminus1 cmminus1)Theblue-shift and lower molar extinction coefficient are due toan increase in the energy of the LUMO of the ligand causingthe 120587-120587lowast and d120587-120587lowast transitions to occur at higher energies[24] Also the UV-Vis spectra of JJ-9 display two absorptionbands at 380 and 514 nm and amolar extinction coefficient ofJJ-9 is 47 times 103Mminus1 cmminus1 at 440 nm We also observed thatthe sensitizers JJ-7 and JJ-9 exhibited strong luminescencemaxima at 660ndash700 nm when they were excited with theirMLCT bands in EtOH at 298K
The ultraviolet-visible transmittance spectra of JJ-7 andJJ-9 adsorbed on TiO
2film are shown in Figure 5 together
with the N719 transmittance spectrum as a reference Thetransmittance of JJ-7 and JJ-9 on 5 120583m TiO
2film exhibits
620 and 610 at red (660 nm) and 180 and 150 at
000
005
010
015
020
000
005
010
015
020
Nor
mal
ized
emiss
ion
inte
nsity
Nor
mal
ized
abso
rban
ce
Wavelength (nm)
N719 JJ-7 JJ-9
400 500 600 700 800 900
Figure 4 Absorption and emission spectra of JJ-7 (blue line) JJ-9(orange line) andN719 (red line) in EtOH
blue (440 nm) wavelength for plant production and qualityrespectively which is higher than the corresponding valuefor N719 (480 at red (660 nm) and 70 at blue (440 nm)wavelength) Also the transmittance of JJ-7 and JJ-9 on10 120583mTiO
2film shows 629 and 605 at red (660 nm) and
75 and 63 at blue (440 nm) wavelength for plant produc-tion and quality respectively which is higher than the corre-sponding value for N719 (379 at red (660 nm) and 15 atblue (440 nm) wavelength) The higher transmittance of JJ-7 and JJ-9 compared with N719 is attributable to increased
4 International Journal of Photoenergy
0
10
20
30
40
50
60
70
80
JJ-9
Tran
smitt
ance
()
Wavelength (nm)
N719 JJ-7
300 400 500 600 700 800
(a)
0
10
20
30
40
50
60
70
80
JJ-9Tr
ansm
ittan
ce (
)
Wavelength (nm)
N719 JJ-7
300 400 500 600 700 800
(b)
Figure 5 Transmittance spectra of JJ-7 (blue line) JJ-9 (orange line) andN719 (red line) (a) adsorbed on 5120583m TiO2film and (b) adsorbed
on 10 120583m TiO2film
0
2
4
6
8
10
12
Voltage (V)
JJ-7
N719JJ-9
00 02 04 06 08
Curr
ent d
ensit
y (m
Ac
m2)
(a)
0
2
4
6
8
12
10
16
14
Voltage (V)
JJ-7
N719JJ-9
00 02 04 06 08
Curr
ent d
ensit
y (m
Ac
m2)
(b)
Figure 6 J-V curves of JJ-7 (blue line) JJ-9 (orange line) andN719 (red line) using (a) 5120583m TiO2film and (b) 10 120583m TiO
2film
HOMO-LUMO energy gaps by electron-withdrawing abili-ties in a ligand and low molar extinction coefficient
The J-V curves for the devices based on JJ-7 and JJ-9 are shown and compared with those of N719 in Figure6 Under standard global AM 15 solar conditions when5 120583m TiO
2film was used the JJ-7 and JJ-9 sensitized cell
gave a short circuit photocurrent density (119869sc) of 849 and
940mA cmminus2 an open circuit voltage (119881oc) of 083 and 078Vand a fill factor (FF) of 071 and 069 corresponding to overallconversion efficiency (120578) of 496 and 507 respectively(Table 1) Under the same condition theN719 sensitized cellgave a 119869sc of 1034mA cmminus2 a 119881oc of 082V and a FF of074 corresponding to 120578 of 625 When 10 120583m TiO
2film
was used the JJ-7 and JJ-9 sensitized cell gave short circuit
International Journal of Photoenergy 5
Table 1 Optical redox and DSSC performance parameters of dyes
Dye 120582absanm amp
120582transbnm ()
119864redoxcV 119864
0-0dV 119864LUMO
eV 119869sc (mA cmminus2)(510120583m)
119881oc (V)(510120583m)
FF(510120583m)
120578f ()
(510120583m)
JJ-7 380 514 amp 440 (18)660 (62) 107 208 minus101 8491168 083080 071071 496658
JJ-9 380 514 amp 440 (15)660 (61) 103 206 minus103 9401262 078080 069069 507693
N719 382 524 amp 440 (7)660 (48) 203g (197h) 10341387 082079 074070 625767
aAbsorption spectra were measured in EtOH solution bTransmittance spectra were measured on 1-layer TiO2 film cRedox potential of dyes on TiO2 wasmeasured in CH3CN with 01M (119899-C4H9)4NPF6 as a scan rate of 100mV sminus1 (vs NHE) d1198640-0 values were estimated from the onset of absorption spectrume119864LUMO was calculated by 119864ox minus 1198640-0
fPerformances of DSSCs were measured with 018 cm2 working area Electrolyte 06M DMPImI 005M I2 05M TBPand 01M LiI in acetonitrile gEnergy level calculated by experiment hEnergy level calculated at the B3LYP3-21 G
photocurrent density (119869sc) of 1168 and 1262mA cmminus2 anopen circuit voltage (119881oc) of 080 and 080V and a fill factor(FF) of 071 and 069 corresponding to overall conversionefficiency (120578) of 658 and 693 respectively (Table 1)Under the same condition the N719 sensitized cell gavea 119869sc of 1387mA cmminus2 a 119881oc of 079V and a FF of 070corresponding to 120578 of 767 A slightly lower 119869sc of JJ-7and JJ-9 relative to N719 can be related to the increase oftransmittance and the sparse packing of the JJ-7 and JJ-9 monolayers on the TiO
2electrodes To clarify the above
explanations we measured the amount of dyes adsorbed onTiO2film by desorbing the dyes from the TiO
2surface with
KOH The amounts of three dyes adsorbed on TiO2film
were measured to be 294 times 10minus7 302 times 10minus7 and 376 times10minus7mmol cmminus2 for JJ-7 JJ-9 andN719 respectivelyThe lowadsorption of JJ-7 and JJ-9 can be due to the presence ofbulky protecting groups with electron withdrawing abilitiesof tetra-substituted ammonium groups and the electrostaticrepulsion of negatively charged carboxylic groups
The electrochemical properties of the two sensitizers JJ-7 and JJ-9 were studied by cyclic voltammetry in CH
3CN
with 01M tetrabutylammonium hexafluorophosphate usingTiO2film with adsorbed dyes as working electrode The
oxidation potentials of JJ-7 and JJ-9 adsorbed on TiO2film
show quasi-reversible couples at 107V and 103V versusNHE respectively (Table 1) The RuIIIII oxidation potentialsof JJ-7 and JJ-9 are more positive than that of N719 TheHOMO-LUMO energy band gaps (119864
0-0) of JJ-7 and JJ-9determined from the intersection of absorption and emissionspectra are 208 and 206 eV respectivelymore increased thanthat of N719 (185 eV for experimental calculation [25] and197 eV for theoretical calculation by B3LYP3-21 G [26 27])This reflects the increased electron withdrawing properties ofligand with tetra-substituted ammonium groups The reduc-tion potentials of two dyes calculated from the oxidationpotentials and the 119864
0-0 determined from the intersection ofabsorption and emission spectra are minus101 V for JJ-7 andminus103V for JJ-9 versus NHE A negative shift in the reductionpotential of JJ-7 and JJ-9 compared to N719 is attributableto electron-withdrawing abilities in ligands and increasedHOMO-LUMO energy band gaps
Figure 7 shows intensity of radiation in dye-sensitizedsolar cell using JJ-7 and N719 sensitizers After making box
we have measured the intensity of radiation as in Figure 7The radiation intensities for JJ-7 sensitizers with both 5 and10 120583m TiO
2thickness films are much higher than that of
N719 sensitizer with 5120583m TiO2thickness film This result
demonstrates that the novel JJ-7 sensitizer is very effectivein greenhouse dye-sensitized solar cell to grow plant On theother hand the existingN719 sensitizer is not useful becauseof the low quantity of lightThe different light quantity mightbe caused by the differentmolecular structure of the dyesThehigh quantity of light in JJ-7 compared to that of N719 maybe due to the defects of adsorption of JJ-7 sensitizer on theTiO2electrodes
In conclusion two novel ruthenium bipyridyl sensitiz-ers have been synthesized and characterized A solar-to-electricity conversion efficiency of 496 (for 5120583mTiO
2film)
and 658 (for 10 120583m TiO2film) for JJ-7 is comparable to
625 (for 5120583m TiO2film) and 767 (for 10 120583m TiO
2film)
for the N719-sensitized solar cell The high transmittance(62 at 660 nm and 18 at 440 nm) of JJ-7 is attributed toits low absorption extinction coefficient ofMLCT band in thevisible region and blue-shift by an increased HOMO-LUMOenergy band gap We believe that the development of highlyefficient sensitizers for greenhouse dye-sensitized solar cellis possible through meticulously molecular engineering andwork on these is now in progress
3 Experimental Section
31 Fabrication of Dye-Sensitized Solar Cells Fluorine-dopedtin oxide (FTO) glass plates (Pilkington TEC Glass-TEC8 solar 23mm thickness) were cleaned in a detergentsolution using an ultrasonic bath for 30min and then rinsedwith water and ethanol Then the plates were immersed in40mM TiCl
4(aqueous) at 70∘C for 30min and washed with
water and ethanol A transparent nanocrystalline layer wasprepared on the FTO glass plates by using a doctor bladeprinting TiO
2paste (Solaronix Ti-Nanoxide TSP) which
was then dried for 2 h at 25∘C The TiO2electrodes were
gradually heated under an air flow at 325∘C for 5min at375∘C for 5min at 450∘C for 15min and at 500∘C for 15minThe thickness of the transparent layer was measured by usingan Alpha-step 250 surface profilometer (Tencor InstrumentsSan Jose CA) The resulting film was composed of a 5
6 International Journal of Photoenergy
200
400
600
800
1000
1200
1400
1600
1800
2000
2200
Time
Out10 times 10 N7195120583m
10 times 10 JJ-7 10120583m10 times 10 JJ-7 5120583m
8 10 12 14 16 18
(120583m
olm
2s)
Figure 7 The intensity of radiation for JJ-7 (5120583m black line) JJ-7 (10120583m red line) N719 (5120583m green line) and out (blue line) andgreenhouse test-bed of dye-sensitized solar cell using new sensitizer (JJ-7)
and 10 120583m thick transparent layer The TiO2electrodes were
treated again with TiCl4at 70∘C for 30min and sintered at
500∘C for 30minThen they were immersed in JJ-7 and JJ-9(03mM in ethanol) solutions and kept at room temperaturefor 24 h FTO plates for the counter electrodes were cleanedin an ultrasonic bath in H
2O acetone and 01M aqueous
HCl subsequently The counter electrodes were preparedby placing a drop of an H
2PtCl6solution (2mg Pt in 1mL
ethanol) on an FTO plate and heating it (at 400∘C) for15minThe dye adsorbed TiO
2electrodes and the Pt counter
electrodes were assembled into a sealed sandwich-type cellby heating at 80∘C using a hot-melt ionomer film (Surlyn)as a spacer between the electrodes A drop of the electrolyteconsisting of 06M 12-dimethyl-3-propylimidazolium iodide(DMPII) 005M I
2 01M LiI and 05M tert-butylpyridine
in acetonitrile was placed in the drilled hole of the counterelectrode and was driven into the cell via vacuum backfillingFinally the hole was sealed using additional Surlyn and acover glass (01mm thickness)
32 Typical Procedures and Analytical Data
JJ-7 Complex A mixture of N3 (100mg 0141mmol)and trimethylphenylammonium hydroxide (434mg0708mmol) in MeOH (2mL) was stirred at room temp-erature for 2 h The pure product JJ-7 was obtained bySephadex LH-20 column with methanol as eluent Yield97 1H NMR (CD
3OD) 943 (d 2H 119869 = 57Hz) 890
(s 2H) 874 (s 2H) 813 (dd 2H 119869 = 57Hz) 793 (m6H) 763ndash750 (m 18H 370 (s 36H) Anal calcd forC62H68N10O8RuS2 C 5974 H 550 Found C 5977
H548
JJ-9 Complex A mixture of N3 (100mg 0141mmol)and benzyltrimethylammonium hydroxide (296mg
0708mmol) in MeOH (2mL) was stirred at room tempera-ture for 2 hThe pure product JJ-9 was obtained by SephadexLH-20 column with methanol as eluent Yield 94 1HNMR (CD
3OD) 941 (d 2H 119869 = 58Hz) 891 (s 2H) 875
(s 2H) 810 (dd 2H 119869 = 58Hz) 754 (m 24H) 455 (s 8H)312 (s 36H) Anal calcd for C
66H76N10O8RuS2 C 6086 H
588 Found C 6078 H 594
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgment
This work was supported by Electronics and Telecommuni-cations Research Institute (ETRI)
References
[1] B OrsquoRegan and M Gratzel ldquoA low-cost high-efficiency solarcell based on dye-sensitized colloidal TiO
2filmsrdquo Nature vol
353 pp 737ndash740 1991[2] K Hara H Sugihara Y Tachibana et al ldquoDye-sensitized nano-
crystalline TiO2solar cells based on ruthenium(II) phenanthro-
line complex photosensitizersrdquo Langmuir vol 17 no 19 pp5992ndash5999 2001
[3] T Horiuchi H Miura K Sumioka and S Uchida ldquoHigh effi-ciency of dye-sensitized solar cells based onmetal-free indolinedyesrdquo Journal of the American Chemical Society vol 126 no 39pp 12218ndash12219 2004
[4] S A Haque S Handa K Peter E PalomaresMThelakkat andJ RDurrant ldquoSupermolecular control of charge transfer in dye-sensitized Nanocrystalline TiO
2films towards a quantitative
International Journal of Photoenergy 7
structure-function relationshiprdquo Angewandte Chemie Interna-tional Edition vol 44 no 35 pp 5740ndash5744 2005
[5] DKuang PWalter FNuesch et al ldquoCo-sensitization of organicdyes for efficient ionic liquid electrolyte-based dye-sensitizedsolar cellsrdquo Langmuir vol 23 no 22 pp 10906ndash10909 2007
[6] T Renouard R A Fallahpour M K Nazeeruddin et al ldquoNovelruthenium sensitizers containing functionalized hybrid tetra-dentate ligands Synthesis characterization and INDOS anal-ysisrdquo Inorganic Chemistry vol 41 no 2 pp 367ndash378 2002
[7] M K Nazeeruddin P Pechy T Renouard et al ldquoEngineeringof efficient panchromatic sensitizers for nanocrystalline TiO
2-
based solar cellsrdquo Journal of the American Chemical Society vol123 no 8 pp 1613ndash1624 2001
[8] K Chen Y-H Hong Y Chi W-H Liu B-S Chen and P-TChou ldquoStrategic design and synthesis of novel tridentate bipyri-dine pyrazolate coupled Ru(II) complexes to achieve superiorsolar conversion efficiencyrdquo Journal of Materials Chemistry vol19 no 30 pp 5329ndash5335 2009
[9] S Pearson A E Wheldon and P Hadley ldquoRadiation transmis-sion and fluorescence of nine greenhouse cladding materialsrdquoJournal of Agricultural Engineering Research vol 62 no 1 pp61ndash70 1995
[10] C Kittas and A Baille ldquoDetermination of the spectral proper-ties of several greenhouse covermaterials and evaluation of spe-cific parameters related to plant responserdquo Journal of Agricul-tural Engineering Research vol 71 no 2 pp 193ndash202 1998
[11] S Tazawa ldquoEffects of various radiant sources on plant growth(part 1)rdquo Japan Agricultural Research Quarterly vol 33 p 1631999
[12] S Hemming E van Os A Dieleman et al ldquoPossibilities ofincreasing production and quality of strawberry fruits andseveral flowers by new blue fluorescent greenhouse filmsrdquo ActaHorticulturae vol 691 pp 225ndash232 2005
[13] E Espı A Salmeron A Fontecha Y Garcıa and A I RealldquoPlastic films for agricultural applicationsrdquo Journal of PlasticFilm and Sheeting vol 22 no 2 pp 85ndash102 2006
[14] W Fang and R C JaoTransplant Production in the 21st Century2000
[15] RMoe S O Grimstad andH R Gisleroslashd ldquoThe use of artificiallight in year round production of greenhouse crops in NorwayrdquoActa Horticulturae vol 711 pp 35ndash42 2006
[16] H-H Kim R M Wheeler J C Sager N C Yorio and GD Goins ldquoLight-emitting diodes as an illumination source forplants a review of research at Kennedy Space Centerrdquo Habita-tion vol 10 no 2 pp 71ndash78 2005
[17] E Ono and H Watanabe ldquoPlant factories blossomrdquo ResourceEngineering amp Technology for Sustainable World vol 13 no 2pp 13ndash14 2006
[18] R C Morrow ldquoLED lighting in horticulturerdquo HortScience vol43 no 7 pp 1947ndash1950 2008
[19] G D Massa H H Kim R M Wheeler and C A MitchellldquoPlant productivity in response to LED lightingrdquo HortSciencevol 43 no 7 pp 1951ndash1956 2008
[20] N Yeh and J-P Chung ldquoHigh-brightness LEDsmdashenergy effi-cient lighting sources and their potential in indoor plant culti-vationrdquo Renewable and Sustainable Energy Reviews vol 13 no8 pp 2175ndash2180 2009
[21] I Vanninen D M Pinto A I Nissinen N S Johansen and LShipp ldquoIn the light of new greenhouse technologies 1 Plant-mediated effects of artificial lighting on arthropods and tritro-phic interactionsrdquo Annals of Applied Biology vol 157 no 3 pp393ndash414 2010
[22] T Bessho E Yoneda J-H Yum et al ldquoNew paradigm inmolecular engineering of sensitizers for solar cell applicationsrdquoJournal of the American Chemical Society vol 131 no 16 pp5930ndash5934 2009
[23] F Mater T H Ghaddar K Walley T DosSantos J R Durrantand B OrsquoRegan ldquoA new ruthenium polypyridyl dye TG6whose performance in dye-sensitized solar cells is surprisinglyclose to that of N719 the lsquodye to beatrsquo for 17 years rdquo Journal ofMaterials Chemistry vol 18 pp 4246ndash4253 2008
[24] M K Nazeeruddin R Humphry-Baker P Liska and MGratzel ldquoInvestigation of sensitizer adsorption and the influ-ence of protons on current and voltage of a dye-sensitized nano-crystalline TiO
2solar cellrdquoThe Journal of Physical Chemistry B
vol 107 no 34 pp 8981ndash8987 2003[25] Y Lee S R Jang R Vittal andK J Kim ldquoDinuclear Ru(II) dyes
for improved performance of dye-sensitized TiO2solar cellsrdquo
New Journal of Chemistry vol 31 no 12 pp 2120ndash2126 2007[26] M K Nazeeruddin F De Angelis S Fantacci et al ldquoCom-
bined experimental and DFT-TDDFT computational study ofphotoelectrochemical cell ruthenium sensitizersrdquo Journal of theAmerican Chemical Society vol 127 no 48 pp 16835ndash168472005
[27] M K Nazeeruddin T Bessho L Cevey et al ldquoA high molarextinction coefficient charge transfer sensitizer and its applica-tion in dye-sensitized solar cellrdquo Journal of Photochemistry andPhotobiology A Chemistry vol 185 no 2-3 pp 331ndash337 2007
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Inorganic ChemistryInternational Journal of
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
International Journal ofPhotoenergy
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Carbohydrate Chemistry
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Advances in
Physical Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom
Analytical Methods in Chemistry
Journal of
Volume 2014
Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
SpectroscopyInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Medicinal ChemistryInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chromatography Research International
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Applied ChemistryJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Theoretical ChemistryJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Spectroscopy
Analytical ChemistryInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Quantum Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Organic Chemistry International
ElectrochemistryInternational Journal of
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CatalystsJournal of
4 International Journal of Photoenergy
0
10
20
30
40
50
60
70
80
JJ-9
Tran
smitt
ance
()
Wavelength (nm)
N719 JJ-7
300 400 500 600 700 800
(a)
0
10
20
30
40
50
60
70
80
JJ-9Tr
ansm
ittan
ce (
)
Wavelength (nm)
N719 JJ-7
300 400 500 600 700 800
(b)
Figure 5 Transmittance spectra of JJ-7 (blue line) JJ-9 (orange line) andN719 (red line) (a) adsorbed on 5120583m TiO2film and (b) adsorbed
on 10 120583m TiO2film
0
2
4
6
8
10
12
Voltage (V)
JJ-7
N719JJ-9
00 02 04 06 08
Curr
ent d
ensit
y (m
Ac
m2)
(a)
0
2
4
6
8
12
10
16
14
Voltage (V)
JJ-7
N719JJ-9
00 02 04 06 08
Curr
ent d
ensit
y (m
Ac
m2)
(b)
Figure 6 J-V curves of JJ-7 (blue line) JJ-9 (orange line) andN719 (red line) using (a) 5120583m TiO2film and (b) 10 120583m TiO
2film
HOMO-LUMO energy gaps by electron-withdrawing abili-ties in a ligand and low molar extinction coefficient
The J-V curves for the devices based on JJ-7 and JJ-9 are shown and compared with those of N719 in Figure6 Under standard global AM 15 solar conditions when5 120583m TiO
2film was used the JJ-7 and JJ-9 sensitized cell
gave a short circuit photocurrent density (119869sc) of 849 and
940mA cmminus2 an open circuit voltage (119881oc) of 083 and 078Vand a fill factor (FF) of 071 and 069 corresponding to overallconversion efficiency (120578) of 496 and 507 respectively(Table 1) Under the same condition theN719 sensitized cellgave a 119869sc of 1034mA cmminus2 a 119881oc of 082V and a FF of074 corresponding to 120578 of 625 When 10 120583m TiO
2film
was used the JJ-7 and JJ-9 sensitized cell gave short circuit
International Journal of Photoenergy 5
Table 1 Optical redox and DSSC performance parameters of dyes
Dye 120582absanm amp
120582transbnm ()
119864redoxcV 119864
0-0dV 119864LUMO
eV 119869sc (mA cmminus2)(510120583m)
119881oc (V)(510120583m)
FF(510120583m)
120578f ()
(510120583m)
JJ-7 380 514 amp 440 (18)660 (62) 107 208 minus101 8491168 083080 071071 496658
JJ-9 380 514 amp 440 (15)660 (61) 103 206 minus103 9401262 078080 069069 507693
N719 382 524 amp 440 (7)660 (48) 203g (197h) 10341387 082079 074070 625767
aAbsorption spectra were measured in EtOH solution bTransmittance spectra were measured on 1-layer TiO2 film cRedox potential of dyes on TiO2 wasmeasured in CH3CN with 01M (119899-C4H9)4NPF6 as a scan rate of 100mV sminus1 (vs NHE) d1198640-0 values were estimated from the onset of absorption spectrume119864LUMO was calculated by 119864ox minus 1198640-0
fPerformances of DSSCs were measured with 018 cm2 working area Electrolyte 06M DMPImI 005M I2 05M TBPand 01M LiI in acetonitrile gEnergy level calculated by experiment hEnergy level calculated at the B3LYP3-21 G
photocurrent density (119869sc) of 1168 and 1262mA cmminus2 anopen circuit voltage (119881oc) of 080 and 080V and a fill factor(FF) of 071 and 069 corresponding to overall conversionefficiency (120578) of 658 and 693 respectively (Table 1)Under the same condition the N719 sensitized cell gavea 119869sc of 1387mA cmminus2 a 119881oc of 079V and a FF of 070corresponding to 120578 of 767 A slightly lower 119869sc of JJ-7and JJ-9 relative to N719 can be related to the increase oftransmittance and the sparse packing of the JJ-7 and JJ-9 monolayers on the TiO
2electrodes To clarify the above
explanations we measured the amount of dyes adsorbed onTiO2film by desorbing the dyes from the TiO
2surface with
KOH The amounts of three dyes adsorbed on TiO2film
were measured to be 294 times 10minus7 302 times 10minus7 and 376 times10minus7mmol cmminus2 for JJ-7 JJ-9 andN719 respectivelyThe lowadsorption of JJ-7 and JJ-9 can be due to the presence ofbulky protecting groups with electron withdrawing abilitiesof tetra-substituted ammonium groups and the electrostaticrepulsion of negatively charged carboxylic groups
The electrochemical properties of the two sensitizers JJ-7 and JJ-9 were studied by cyclic voltammetry in CH
3CN
with 01M tetrabutylammonium hexafluorophosphate usingTiO2film with adsorbed dyes as working electrode The
oxidation potentials of JJ-7 and JJ-9 adsorbed on TiO2film
show quasi-reversible couples at 107V and 103V versusNHE respectively (Table 1) The RuIIIII oxidation potentialsof JJ-7 and JJ-9 are more positive than that of N719 TheHOMO-LUMO energy band gaps (119864
0-0) of JJ-7 and JJ-9determined from the intersection of absorption and emissionspectra are 208 and 206 eV respectivelymore increased thanthat of N719 (185 eV for experimental calculation [25] and197 eV for theoretical calculation by B3LYP3-21 G [26 27])This reflects the increased electron withdrawing properties ofligand with tetra-substituted ammonium groups The reduc-tion potentials of two dyes calculated from the oxidationpotentials and the 119864
0-0 determined from the intersection ofabsorption and emission spectra are minus101 V for JJ-7 andminus103V for JJ-9 versus NHE A negative shift in the reductionpotential of JJ-7 and JJ-9 compared to N719 is attributableto electron-withdrawing abilities in ligands and increasedHOMO-LUMO energy band gaps
Figure 7 shows intensity of radiation in dye-sensitizedsolar cell using JJ-7 and N719 sensitizers After making box
we have measured the intensity of radiation as in Figure 7The radiation intensities for JJ-7 sensitizers with both 5 and10 120583m TiO
2thickness films are much higher than that of
N719 sensitizer with 5120583m TiO2thickness film This result
demonstrates that the novel JJ-7 sensitizer is very effectivein greenhouse dye-sensitized solar cell to grow plant On theother hand the existingN719 sensitizer is not useful becauseof the low quantity of lightThe different light quantity mightbe caused by the differentmolecular structure of the dyesThehigh quantity of light in JJ-7 compared to that of N719 maybe due to the defects of adsorption of JJ-7 sensitizer on theTiO2electrodes
In conclusion two novel ruthenium bipyridyl sensitiz-ers have been synthesized and characterized A solar-to-electricity conversion efficiency of 496 (for 5120583mTiO
2film)
and 658 (for 10 120583m TiO2film) for JJ-7 is comparable to
625 (for 5120583m TiO2film) and 767 (for 10 120583m TiO
2film)
for the N719-sensitized solar cell The high transmittance(62 at 660 nm and 18 at 440 nm) of JJ-7 is attributed toits low absorption extinction coefficient ofMLCT band in thevisible region and blue-shift by an increased HOMO-LUMOenergy band gap We believe that the development of highlyefficient sensitizers for greenhouse dye-sensitized solar cellis possible through meticulously molecular engineering andwork on these is now in progress
3 Experimental Section
31 Fabrication of Dye-Sensitized Solar Cells Fluorine-dopedtin oxide (FTO) glass plates (Pilkington TEC Glass-TEC8 solar 23mm thickness) were cleaned in a detergentsolution using an ultrasonic bath for 30min and then rinsedwith water and ethanol Then the plates were immersed in40mM TiCl
4(aqueous) at 70∘C for 30min and washed with
water and ethanol A transparent nanocrystalline layer wasprepared on the FTO glass plates by using a doctor bladeprinting TiO
2paste (Solaronix Ti-Nanoxide TSP) which
was then dried for 2 h at 25∘C The TiO2electrodes were
gradually heated under an air flow at 325∘C for 5min at375∘C for 5min at 450∘C for 15min and at 500∘C for 15minThe thickness of the transparent layer was measured by usingan Alpha-step 250 surface profilometer (Tencor InstrumentsSan Jose CA) The resulting film was composed of a 5
6 International Journal of Photoenergy
200
400
600
800
1000
1200
1400
1600
1800
2000
2200
Time
Out10 times 10 N7195120583m
10 times 10 JJ-7 10120583m10 times 10 JJ-7 5120583m
8 10 12 14 16 18
(120583m
olm
2s)
Figure 7 The intensity of radiation for JJ-7 (5120583m black line) JJ-7 (10120583m red line) N719 (5120583m green line) and out (blue line) andgreenhouse test-bed of dye-sensitized solar cell using new sensitizer (JJ-7)
and 10 120583m thick transparent layer The TiO2electrodes were
treated again with TiCl4at 70∘C for 30min and sintered at
500∘C for 30minThen they were immersed in JJ-7 and JJ-9(03mM in ethanol) solutions and kept at room temperaturefor 24 h FTO plates for the counter electrodes were cleanedin an ultrasonic bath in H
2O acetone and 01M aqueous
HCl subsequently The counter electrodes were preparedby placing a drop of an H
2PtCl6solution (2mg Pt in 1mL
ethanol) on an FTO plate and heating it (at 400∘C) for15minThe dye adsorbed TiO
2electrodes and the Pt counter
electrodes were assembled into a sealed sandwich-type cellby heating at 80∘C using a hot-melt ionomer film (Surlyn)as a spacer between the electrodes A drop of the electrolyteconsisting of 06M 12-dimethyl-3-propylimidazolium iodide(DMPII) 005M I
2 01M LiI and 05M tert-butylpyridine
in acetonitrile was placed in the drilled hole of the counterelectrode and was driven into the cell via vacuum backfillingFinally the hole was sealed using additional Surlyn and acover glass (01mm thickness)
32 Typical Procedures and Analytical Data
JJ-7 Complex A mixture of N3 (100mg 0141mmol)and trimethylphenylammonium hydroxide (434mg0708mmol) in MeOH (2mL) was stirred at room temp-erature for 2 h The pure product JJ-7 was obtained bySephadex LH-20 column with methanol as eluent Yield97 1H NMR (CD
3OD) 943 (d 2H 119869 = 57Hz) 890
(s 2H) 874 (s 2H) 813 (dd 2H 119869 = 57Hz) 793 (m6H) 763ndash750 (m 18H 370 (s 36H) Anal calcd forC62H68N10O8RuS2 C 5974 H 550 Found C 5977
H548
JJ-9 Complex A mixture of N3 (100mg 0141mmol)and benzyltrimethylammonium hydroxide (296mg
0708mmol) in MeOH (2mL) was stirred at room tempera-ture for 2 hThe pure product JJ-9 was obtained by SephadexLH-20 column with methanol as eluent Yield 94 1HNMR (CD
3OD) 941 (d 2H 119869 = 58Hz) 891 (s 2H) 875
(s 2H) 810 (dd 2H 119869 = 58Hz) 754 (m 24H) 455 (s 8H)312 (s 36H) Anal calcd for C
66H76N10O8RuS2 C 6086 H
588 Found C 6078 H 594
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgment
This work was supported by Electronics and Telecommuni-cations Research Institute (ETRI)
References
[1] B OrsquoRegan and M Gratzel ldquoA low-cost high-efficiency solarcell based on dye-sensitized colloidal TiO
2filmsrdquo Nature vol
353 pp 737ndash740 1991[2] K Hara H Sugihara Y Tachibana et al ldquoDye-sensitized nano-
crystalline TiO2solar cells based on ruthenium(II) phenanthro-
line complex photosensitizersrdquo Langmuir vol 17 no 19 pp5992ndash5999 2001
[3] T Horiuchi H Miura K Sumioka and S Uchida ldquoHigh effi-ciency of dye-sensitized solar cells based onmetal-free indolinedyesrdquo Journal of the American Chemical Society vol 126 no 39pp 12218ndash12219 2004
[4] S A Haque S Handa K Peter E PalomaresMThelakkat andJ RDurrant ldquoSupermolecular control of charge transfer in dye-sensitized Nanocrystalline TiO
2films towards a quantitative
International Journal of Photoenergy 7
structure-function relationshiprdquo Angewandte Chemie Interna-tional Edition vol 44 no 35 pp 5740ndash5744 2005
[5] DKuang PWalter FNuesch et al ldquoCo-sensitization of organicdyes for efficient ionic liquid electrolyte-based dye-sensitizedsolar cellsrdquo Langmuir vol 23 no 22 pp 10906ndash10909 2007
[6] T Renouard R A Fallahpour M K Nazeeruddin et al ldquoNovelruthenium sensitizers containing functionalized hybrid tetra-dentate ligands Synthesis characterization and INDOS anal-ysisrdquo Inorganic Chemistry vol 41 no 2 pp 367ndash378 2002
[7] M K Nazeeruddin P Pechy T Renouard et al ldquoEngineeringof efficient panchromatic sensitizers for nanocrystalline TiO
2-
based solar cellsrdquo Journal of the American Chemical Society vol123 no 8 pp 1613ndash1624 2001
[8] K Chen Y-H Hong Y Chi W-H Liu B-S Chen and P-TChou ldquoStrategic design and synthesis of novel tridentate bipyri-dine pyrazolate coupled Ru(II) complexes to achieve superiorsolar conversion efficiencyrdquo Journal of Materials Chemistry vol19 no 30 pp 5329ndash5335 2009
[9] S Pearson A E Wheldon and P Hadley ldquoRadiation transmis-sion and fluorescence of nine greenhouse cladding materialsrdquoJournal of Agricultural Engineering Research vol 62 no 1 pp61ndash70 1995
[10] C Kittas and A Baille ldquoDetermination of the spectral proper-ties of several greenhouse covermaterials and evaluation of spe-cific parameters related to plant responserdquo Journal of Agricul-tural Engineering Research vol 71 no 2 pp 193ndash202 1998
[11] S Tazawa ldquoEffects of various radiant sources on plant growth(part 1)rdquo Japan Agricultural Research Quarterly vol 33 p 1631999
[12] S Hemming E van Os A Dieleman et al ldquoPossibilities ofincreasing production and quality of strawberry fruits andseveral flowers by new blue fluorescent greenhouse filmsrdquo ActaHorticulturae vol 691 pp 225ndash232 2005
[13] E Espı A Salmeron A Fontecha Y Garcıa and A I RealldquoPlastic films for agricultural applicationsrdquo Journal of PlasticFilm and Sheeting vol 22 no 2 pp 85ndash102 2006
[14] W Fang and R C JaoTransplant Production in the 21st Century2000
[15] RMoe S O Grimstad andH R Gisleroslashd ldquoThe use of artificiallight in year round production of greenhouse crops in NorwayrdquoActa Horticulturae vol 711 pp 35ndash42 2006
[16] H-H Kim R M Wheeler J C Sager N C Yorio and GD Goins ldquoLight-emitting diodes as an illumination source forplants a review of research at Kennedy Space Centerrdquo Habita-tion vol 10 no 2 pp 71ndash78 2005
[17] E Ono and H Watanabe ldquoPlant factories blossomrdquo ResourceEngineering amp Technology for Sustainable World vol 13 no 2pp 13ndash14 2006
[18] R C Morrow ldquoLED lighting in horticulturerdquo HortScience vol43 no 7 pp 1947ndash1950 2008
[19] G D Massa H H Kim R M Wheeler and C A MitchellldquoPlant productivity in response to LED lightingrdquo HortSciencevol 43 no 7 pp 1951ndash1956 2008
[20] N Yeh and J-P Chung ldquoHigh-brightness LEDsmdashenergy effi-cient lighting sources and their potential in indoor plant culti-vationrdquo Renewable and Sustainable Energy Reviews vol 13 no8 pp 2175ndash2180 2009
[21] I Vanninen D M Pinto A I Nissinen N S Johansen and LShipp ldquoIn the light of new greenhouse technologies 1 Plant-mediated effects of artificial lighting on arthropods and tritro-phic interactionsrdquo Annals of Applied Biology vol 157 no 3 pp393ndash414 2010
[22] T Bessho E Yoneda J-H Yum et al ldquoNew paradigm inmolecular engineering of sensitizers for solar cell applicationsrdquoJournal of the American Chemical Society vol 131 no 16 pp5930ndash5934 2009
[23] F Mater T H Ghaddar K Walley T DosSantos J R Durrantand B OrsquoRegan ldquoA new ruthenium polypyridyl dye TG6whose performance in dye-sensitized solar cells is surprisinglyclose to that of N719 the lsquodye to beatrsquo for 17 years rdquo Journal ofMaterials Chemistry vol 18 pp 4246ndash4253 2008
[24] M K Nazeeruddin R Humphry-Baker P Liska and MGratzel ldquoInvestigation of sensitizer adsorption and the influ-ence of protons on current and voltage of a dye-sensitized nano-crystalline TiO
2solar cellrdquoThe Journal of Physical Chemistry B
vol 107 no 34 pp 8981ndash8987 2003[25] Y Lee S R Jang R Vittal andK J Kim ldquoDinuclear Ru(II) dyes
for improved performance of dye-sensitized TiO2solar cellsrdquo
New Journal of Chemistry vol 31 no 12 pp 2120ndash2126 2007[26] M K Nazeeruddin F De Angelis S Fantacci et al ldquoCom-
bined experimental and DFT-TDDFT computational study ofphotoelectrochemical cell ruthenium sensitizersrdquo Journal of theAmerican Chemical Society vol 127 no 48 pp 16835ndash168472005
[27] M K Nazeeruddin T Bessho L Cevey et al ldquoA high molarextinction coefficient charge transfer sensitizer and its applica-tion in dye-sensitized solar cellrdquo Journal of Photochemistry andPhotobiology A Chemistry vol 185 no 2-3 pp 331ndash337 2007
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Inorganic ChemistryInternational Journal of
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
International Journal ofPhotoenergy
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Carbohydrate Chemistry
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Advances in
Physical Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom
Analytical Methods in Chemistry
Journal of
Volume 2014
Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
SpectroscopyInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Medicinal ChemistryInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chromatography Research International
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Applied ChemistryJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Theoretical ChemistryJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Spectroscopy
Analytical ChemistryInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Quantum Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Organic Chemistry International
ElectrochemistryInternational Journal of
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CatalystsJournal of
International Journal of Photoenergy 5
Table 1 Optical redox and DSSC performance parameters of dyes
Dye 120582absanm amp
120582transbnm ()
119864redoxcV 119864
0-0dV 119864LUMO
eV 119869sc (mA cmminus2)(510120583m)
119881oc (V)(510120583m)
FF(510120583m)
120578f ()
(510120583m)
JJ-7 380 514 amp 440 (18)660 (62) 107 208 minus101 8491168 083080 071071 496658
JJ-9 380 514 amp 440 (15)660 (61) 103 206 minus103 9401262 078080 069069 507693
N719 382 524 amp 440 (7)660 (48) 203g (197h) 10341387 082079 074070 625767
aAbsorption spectra were measured in EtOH solution bTransmittance spectra were measured on 1-layer TiO2 film cRedox potential of dyes on TiO2 wasmeasured in CH3CN with 01M (119899-C4H9)4NPF6 as a scan rate of 100mV sminus1 (vs NHE) d1198640-0 values were estimated from the onset of absorption spectrume119864LUMO was calculated by 119864ox minus 1198640-0
fPerformances of DSSCs were measured with 018 cm2 working area Electrolyte 06M DMPImI 005M I2 05M TBPand 01M LiI in acetonitrile gEnergy level calculated by experiment hEnergy level calculated at the B3LYP3-21 G
photocurrent density (119869sc) of 1168 and 1262mA cmminus2 anopen circuit voltage (119881oc) of 080 and 080V and a fill factor(FF) of 071 and 069 corresponding to overall conversionefficiency (120578) of 658 and 693 respectively (Table 1)Under the same condition the N719 sensitized cell gavea 119869sc of 1387mA cmminus2 a 119881oc of 079V and a FF of 070corresponding to 120578 of 767 A slightly lower 119869sc of JJ-7and JJ-9 relative to N719 can be related to the increase oftransmittance and the sparse packing of the JJ-7 and JJ-9 monolayers on the TiO
2electrodes To clarify the above
explanations we measured the amount of dyes adsorbed onTiO2film by desorbing the dyes from the TiO
2surface with
KOH The amounts of three dyes adsorbed on TiO2film
were measured to be 294 times 10minus7 302 times 10minus7 and 376 times10minus7mmol cmminus2 for JJ-7 JJ-9 andN719 respectivelyThe lowadsorption of JJ-7 and JJ-9 can be due to the presence ofbulky protecting groups with electron withdrawing abilitiesof tetra-substituted ammonium groups and the electrostaticrepulsion of negatively charged carboxylic groups
The electrochemical properties of the two sensitizers JJ-7 and JJ-9 were studied by cyclic voltammetry in CH
3CN
with 01M tetrabutylammonium hexafluorophosphate usingTiO2film with adsorbed dyes as working electrode The
oxidation potentials of JJ-7 and JJ-9 adsorbed on TiO2film
show quasi-reversible couples at 107V and 103V versusNHE respectively (Table 1) The RuIIIII oxidation potentialsof JJ-7 and JJ-9 are more positive than that of N719 TheHOMO-LUMO energy band gaps (119864
0-0) of JJ-7 and JJ-9determined from the intersection of absorption and emissionspectra are 208 and 206 eV respectivelymore increased thanthat of N719 (185 eV for experimental calculation [25] and197 eV for theoretical calculation by B3LYP3-21 G [26 27])This reflects the increased electron withdrawing properties ofligand with tetra-substituted ammonium groups The reduc-tion potentials of two dyes calculated from the oxidationpotentials and the 119864
0-0 determined from the intersection ofabsorption and emission spectra are minus101 V for JJ-7 andminus103V for JJ-9 versus NHE A negative shift in the reductionpotential of JJ-7 and JJ-9 compared to N719 is attributableto electron-withdrawing abilities in ligands and increasedHOMO-LUMO energy band gaps
Figure 7 shows intensity of radiation in dye-sensitizedsolar cell using JJ-7 and N719 sensitizers After making box
we have measured the intensity of radiation as in Figure 7The radiation intensities for JJ-7 sensitizers with both 5 and10 120583m TiO
2thickness films are much higher than that of
N719 sensitizer with 5120583m TiO2thickness film This result
demonstrates that the novel JJ-7 sensitizer is very effectivein greenhouse dye-sensitized solar cell to grow plant On theother hand the existingN719 sensitizer is not useful becauseof the low quantity of lightThe different light quantity mightbe caused by the differentmolecular structure of the dyesThehigh quantity of light in JJ-7 compared to that of N719 maybe due to the defects of adsorption of JJ-7 sensitizer on theTiO2electrodes
In conclusion two novel ruthenium bipyridyl sensitiz-ers have been synthesized and characterized A solar-to-electricity conversion efficiency of 496 (for 5120583mTiO
2film)
and 658 (for 10 120583m TiO2film) for JJ-7 is comparable to
625 (for 5120583m TiO2film) and 767 (for 10 120583m TiO
2film)
for the N719-sensitized solar cell The high transmittance(62 at 660 nm and 18 at 440 nm) of JJ-7 is attributed toits low absorption extinction coefficient ofMLCT band in thevisible region and blue-shift by an increased HOMO-LUMOenergy band gap We believe that the development of highlyefficient sensitizers for greenhouse dye-sensitized solar cellis possible through meticulously molecular engineering andwork on these is now in progress
3 Experimental Section
31 Fabrication of Dye-Sensitized Solar Cells Fluorine-dopedtin oxide (FTO) glass plates (Pilkington TEC Glass-TEC8 solar 23mm thickness) were cleaned in a detergentsolution using an ultrasonic bath for 30min and then rinsedwith water and ethanol Then the plates were immersed in40mM TiCl
4(aqueous) at 70∘C for 30min and washed with
water and ethanol A transparent nanocrystalline layer wasprepared on the FTO glass plates by using a doctor bladeprinting TiO
2paste (Solaronix Ti-Nanoxide TSP) which
was then dried for 2 h at 25∘C The TiO2electrodes were
gradually heated under an air flow at 325∘C for 5min at375∘C for 5min at 450∘C for 15min and at 500∘C for 15minThe thickness of the transparent layer was measured by usingan Alpha-step 250 surface profilometer (Tencor InstrumentsSan Jose CA) The resulting film was composed of a 5
6 International Journal of Photoenergy
200
400
600
800
1000
1200
1400
1600
1800
2000
2200
Time
Out10 times 10 N7195120583m
10 times 10 JJ-7 10120583m10 times 10 JJ-7 5120583m
8 10 12 14 16 18
(120583m
olm
2s)
Figure 7 The intensity of radiation for JJ-7 (5120583m black line) JJ-7 (10120583m red line) N719 (5120583m green line) and out (blue line) andgreenhouse test-bed of dye-sensitized solar cell using new sensitizer (JJ-7)
and 10 120583m thick transparent layer The TiO2electrodes were
treated again with TiCl4at 70∘C for 30min and sintered at
500∘C for 30minThen they were immersed in JJ-7 and JJ-9(03mM in ethanol) solutions and kept at room temperaturefor 24 h FTO plates for the counter electrodes were cleanedin an ultrasonic bath in H
2O acetone and 01M aqueous
HCl subsequently The counter electrodes were preparedby placing a drop of an H
2PtCl6solution (2mg Pt in 1mL
ethanol) on an FTO plate and heating it (at 400∘C) for15minThe dye adsorbed TiO
2electrodes and the Pt counter
electrodes were assembled into a sealed sandwich-type cellby heating at 80∘C using a hot-melt ionomer film (Surlyn)as a spacer between the electrodes A drop of the electrolyteconsisting of 06M 12-dimethyl-3-propylimidazolium iodide(DMPII) 005M I
2 01M LiI and 05M tert-butylpyridine
in acetonitrile was placed in the drilled hole of the counterelectrode and was driven into the cell via vacuum backfillingFinally the hole was sealed using additional Surlyn and acover glass (01mm thickness)
32 Typical Procedures and Analytical Data
JJ-7 Complex A mixture of N3 (100mg 0141mmol)and trimethylphenylammonium hydroxide (434mg0708mmol) in MeOH (2mL) was stirred at room temp-erature for 2 h The pure product JJ-7 was obtained bySephadex LH-20 column with methanol as eluent Yield97 1H NMR (CD
3OD) 943 (d 2H 119869 = 57Hz) 890
(s 2H) 874 (s 2H) 813 (dd 2H 119869 = 57Hz) 793 (m6H) 763ndash750 (m 18H 370 (s 36H) Anal calcd forC62H68N10O8RuS2 C 5974 H 550 Found C 5977
H548
JJ-9 Complex A mixture of N3 (100mg 0141mmol)and benzyltrimethylammonium hydroxide (296mg
0708mmol) in MeOH (2mL) was stirred at room tempera-ture for 2 hThe pure product JJ-9 was obtained by SephadexLH-20 column with methanol as eluent Yield 94 1HNMR (CD
3OD) 941 (d 2H 119869 = 58Hz) 891 (s 2H) 875
(s 2H) 810 (dd 2H 119869 = 58Hz) 754 (m 24H) 455 (s 8H)312 (s 36H) Anal calcd for C
66H76N10O8RuS2 C 6086 H
588 Found C 6078 H 594
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgment
This work was supported by Electronics and Telecommuni-cations Research Institute (ETRI)
References
[1] B OrsquoRegan and M Gratzel ldquoA low-cost high-efficiency solarcell based on dye-sensitized colloidal TiO
2filmsrdquo Nature vol
353 pp 737ndash740 1991[2] K Hara H Sugihara Y Tachibana et al ldquoDye-sensitized nano-
crystalline TiO2solar cells based on ruthenium(II) phenanthro-
line complex photosensitizersrdquo Langmuir vol 17 no 19 pp5992ndash5999 2001
[3] T Horiuchi H Miura K Sumioka and S Uchida ldquoHigh effi-ciency of dye-sensitized solar cells based onmetal-free indolinedyesrdquo Journal of the American Chemical Society vol 126 no 39pp 12218ndash12219 2004
[4] S A Haque S Handa K Peter E PalomaresMThelakkat andJ RDurrant ldquoSupermolecular control of charge transfer in dye-sensitized Nanocrystalline TiO
2films towards a quantitative
International Journal of Photoenergy 7
structure-function relationshiprdquo Angewandte Chemie Interna-tional Edition vol 44 no 35 pp 5740ndash5744 2005
[5] DKuang PWalter FNuesch et al ldquoCo-sensitization of organicdyes for efficient ionic liquid electrolyte-based dye-sensitizedsolar cellsrdquo Langmuir vol 23 no 22 pp 10906ndash10909 2007
[6] T Renouard R A Fallahpour M K Nazeeruddin et al ldquoNovelruthenium sensitizers containing functionalized hybrid tetra-dentate ligands Synthesis characterization and INDOS anal-ysisrdquo Inorganic Chemistry vol 41 no 2 pp 367ndash378 2002
[7] M K Nazeeruddin P Pechy T Renouard et al ldquoEngineeringof efficient panchromatic sensitizers for nanocrystalline TiO
2-
based solar cellsrdquo Journal of the American Chemical Society vol123 no 8 pp 1613ndash1624 2001
[8] K Chen Y-H Hong Y Chi W-H Liu B-S Chen and P-TChou ldquoStrategic design and synthesis of novel tridentate bipyri-dine pyrazolate coupled Ru(II) complexes to achieve superiorsolar conversion efficiencyrdquo Journal of Materials Chemistry vol19 no 30 pp 5329ndash5335 2009
[9] S Pearson A E Wheldon and P Hadley ldquoRadiation transmis-sion and fluorescence of nine greenhouse cladding materialsrdquoJournal of Agricultural Engineering Research vol 62 no 1 pp61ndash70 1995
[10] C Kittas and A Baille ldquoDetermination of the spectral proper-ties of several greenhouse covermaterials and evaluation of spe-cific parameters related to plant responserdquo Journal of Agricul-tural Engineering Research vol 71 no 2 pp 193ndash202 1998
[11] S Tazawa ldquoEffects of various radiant sources on plant growth(part 1)rdquo Japan Agricultural Research Quarterly vol 33 p 1631999
[12] S Hemming E van Os A Dieleman et al ldquoPossibilities ofincreasing production and quality of strawberry fruits andseveral flowers by new blue fluorescent greenhouse filmsrdquo ActaHorticulturae vol 691 pp 225ndash232 2005
[13] E Espı A Salmeron A Fontecha Y Garcıa and A I RealldquoPlastic films for agricultural applicationsrdquo Journal of PlasticFilm and Sheeting vol 22 no 2 pp 85ndash102 2006
[14] W Fang and R C JaoTransplant Production in the 21st Century2000
[15] RMoe S O Grimstad andH R Gisleroslashd ldquoThe use of artificiallight in year round production of greenhouse crops in NorwayrdquoActa Horticulturae vol 711 pp 35ndash42 2006
[16] H-H Kim R M Wheeler J C Sager N C Yorio and GD Goins ldquoLight-emitting diodes as an illumination source forplants a review of research at Kennedy Space Centerrdquo Habita-tion vol 10 no 2 pp 71ndash78 2005
[17] E Ono and H Watanabe ldquoPlant factories blossomrdquo ResourceEngineering amp Technology for Sustainable World vol 13 no 2pp 13ndash14 2006
[18] R C Morrow ldquoLED lighting in horticulturerdquo HortScience vol43 no 7 pp 1947ndash1950 2008
[19] G D Massa H H Kim R M Wheeler and C A MitchellldquoPlant productivity in response to LED lightingrdquo HortSciencevol 43 no 7 pp 1951ndash1956 2008
[20] N Yeh and J-P Chung ldquoHigh-brightness LEDsmdashenergy effi-cient lighting sources and their potential in indoor plant culti-vationrdquo Renewable and Sustainable Energy Reviews vol 13 no8 pp 2175ndash2180 2009
[21] I Vanninen D M Pinto A I Nissinen N S Johansen and LShipp ldquoIn the light of new greenhouse technologies 1 Plant-mediated effects of artificial lighting on arthropods and tritro-phic interactionsrdquo Annals of Applied Biology vol 157 no 3 pp393ndash414 2010
[22] T Bessho E Yoneda J-H Yum et al ldquoNew paradigm inmolecular engineering of sensitizers for solar cell applicationsrdquoJournal of the American Chemical Society vol 131 no 16 pp5930ndash5934 2009
[23] F Mater T H Ghaddar K Walley T DosSantos J R Durrantand B OrsquoRegan ldquoA new ruthenium polypyridyl dye TG6whose performance in dye-sensitized solar cells is surprisinglyclose to that of N719 the lsquodye to beatrsquo for 17 years rdquo Journal ofMaterials Chemistry vol 18 pp 4246ndash4253 2008
[24] M K Nazeeruddin R Humphry-Baker P Liska and MGratzel ldquoInvestigation of sensitizer adsorption and the influ-ence of protons on current and voltage of a dye-sensitized nano-crystalline TiO
2solar cellrdquoThe Journal of Physical Chemistry B
vol 107 no 34 pp 8981ndash8987 2003[25] Y Lee S R Jang R Vittal andK J Kim ldquoDinuclear Ru(II) dyes
for improved performance of dye-sensitized TiO2solar cellsrdquo
New Journal of Chemistry vol 31 no 12 pp 2120ndash2126 2007[26] M K Nazeeruddin F De Angelis S Fantacci et al ldquoCom-
bined experimental and DFT-TDDFT computational study ofphotoelectrochemical cell ruthenium sensitizersrdquo Journal of theAmerican Chemical Society vol 127 no 48 pp 16835ndash168472005
[27] M K Nazeeruddin T Bessho L Cevey et al ldquoA high molarextinction coefficient charge transfer sensitizer and its applica-tion in dye-sensitized solar cellrdquo Journal of Photochemistry andPhotobiology A Chemistry vol 185 no 2-3 pp 331ndash337 2007
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Inorganic ChemistryInternational Journal of
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
International Journal ofPhotoenergy
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Carbohydrate Chemistry
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Advances in
Physical Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom
Analytical Methods in Chemistry
Journal of
Volume 2014
Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
SpectroscopyInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Medicinal ChemistryInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chromatography Research International
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Applied ChemistryJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Theoretical ChemistryJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Spectroscopy
Analytical ChemistryInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Quantum Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Organic Chemistry International
ElectrochemistryInternational Journal of
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CatalystsJournal of
6 International Journal of Photoenergy
200
400
600
800
1000
1200
1400
1600
1800
2000
2200
Time
Out10 times 10 N7195120583m
10 times 10 JJ-7 10120583m10 times 10 JJ-7 5120583m
8 10 12 14 16 18
(120583m
olm
2s)
Figure 7 The intensity of radiation for JJ-7 (5120583m black line) JJ-7 (10120583m red line) N719 (5120583m green line) and out (blue line) andgreenhouse test-bed of dye-sensitized solar cell using new sensitizer (JJ-7)
and 10 120583m thick transparent layer The TiO2electrodes were
treated again with TiCl4at 70∘C for 30min and sintered at
500∘C for 30minThen they were immersed in JJ-7 and JJ-9(03mM in ethanol) solutions and kept at room temperaturefor 24 h FTO plates for the counter electrodes were cleanedin an ultrasonic bath in H
2O acetone and 01M aqueous
HCl subsequently The counter electrodes were preparedby placing a drop of an H
2PtCl6solution (2mg Pt in 1mL
ethanol) on an FTO plate and heating it (at 400∘C) for15minThe dye adsorbed TiO
2electrodes and the Pt counter
electrodes were assembled into a sealed sandwich-type cellby heating at 80∘C using a hot-melt ionomer film (Surlyn)as a spacer between the electrodes A drop of the electrolyteconsisting of 06M 12-dimethyl-3-propylimidazolium iodide(DMPII) 005M I
2 01M LiI and 05M tert-butylpyridine
in acetonitrile was placed in the drilled hole of the counterelectrode and was driven into the cell via vacuum backfillingFinally the hole was sealed using additional Surlyn and acover glass (01mm thickness)
32 Typical Procedures and Analytical Data
JJ-7 Complex A mixture of N3 (100mg 0141mmol)and trimethylphenylammonium hydroxide (434mg0708mmol) in MeOH (2mL) was stirred at room temp-erature for 2 h The pure product JJ-7 was obtained bySephadex LH-20 column with methanol as eluent Yield97 1H NMR (CD
3OD) 943 (d 2H 119869 = 57Hz) 890
(s 2H) 874 (s 2H) 813 (dd 2H 119869 = 57Hz) 793 (m6H) 763ndash750 (m 18H 370 (s 36H) Anal calcd forC62H68N10O8RuS2 C 5974 H 550 Found C 5977
H548
JJ-9 Complex A mixture of N3 (100mg 0141mmol)and benzyltrimethylammonium hydroxide (296mg
0708mmol) in MeOH (2mL) was stirred at room tempera-ture for 2 hThe pure product JJ-9 was obtained by SephadexLH-20 column with methanol as eluent Yield 94 1HNMR (CD
3OD) 941 (d 2H 119869 = 58Hz) 891 (s 2H) 875
(s 2H) 810 (dd 2H 119869 = 58Hz) 754 (m 24H) 455 (s 8H)312 (s 36H) Anal calcd for C
66H76N10O8RuS2 C 6086 H
588 Found C 6078 H 594
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgment
This work was supported by Electronics and Telecommuni-cations Research Institute (ETRI)
References
[1] B OrsquoRegan and M Gratzel ldquoA low-cost high-efficiency solarcell based on dye-sensitized colloidal TiO
2filmsrdquo Nature vol
353 pp 737ndash740 1991[2] K Hara H Sugihara Y Tachibana et al ldquoDye-sensitized nano-
crystalline TiO2solar cells based on ruthenium(II) phenanthro-
line complex photosensitizersrdquo Langmuir vol 17 no 19 pp5992ndash5999 2001
[3] T Horiuchi H Miura K Sumioka and S Uchida ldquoHigh effi-ciency of dye-sensitized solar cells based onmetal-free indolinedyesrdquo Journal of the American Chemical Society vol 126 no 39pp 12218ndash12219 2004
[4] S A Haque S Handa K Peter E PalomaresMThelakkat andJ RDurrant ldquoSupermolecular control of charge transfer in dye-sensitized Nanocrystalline TiO
2films towards a quantitative
International Journal of Photoenergy 7
structure-function relationshiprdquo Angewandte Chemie Interna-tional Edition vol 44 no 35 pp 5740ndash5744 2005
[5] DKuang PWalter FNuesch et al ldquoCo-sensitization of organicdyes for efficient ionic liquid electrolyte-based dye-sensitizedsolar cellsrdquo Langmuir vol 23 no 22 pp 10906ndash10909 2007
[6] T Renouard R A Fallahpour M K Nazeeruddin et al ldquoNovelruthenium sensitizers containing functionalized hybrid tetra-dentate ligands Synthesis characterization and INDOS anal-ysisrdquo Inorganic Chemistry vol 41 no 2 pp 367ndash378 2002
[7] M K Nazeeruddin P Pechy T Renouard et al ldquoEngineeringof efficient panchromatic sensitizers for nanocrystalline TiO
2-
based solar cellsrdquo Journal of the American Chemical Society vol123 no 8 pp 1613ndash1624 2001
[8] K Chen Y-H Hong Y Chi W-H Liu B-S Chen and P-TChou ldquoStrategic design and synthesis of novel tridentate bipyri-dine pyrazolate coupled Ru(II) complexes to achieve superiorsolar conversion efficiencyrdquo Journal of Materials Chemistry vol19 no 30 pp 5329ndash5335 2009
[9] S Pearson A E Wheldon and P Hadley ldquoRadiation transmis-sion and fluorescence of nine greenhouse cladding materialsrdquoJournal of Agricultural Engineering Research vol 62 no 1 pp61ndash70 1995
[10] C Kittas and A Baille ldquoDetermination of the spectral proper-ties of several greenhouse covermaterials and evaluation of spe-cific parameters related to plant responserdquo Journal of Agricul-tural Engineering Research vol 71 no 2 pp 193ndash202 1998
[11] S Tazawa ldquoEffects of various radiant sources on plant growth(part 1)rdquo Japan Agricultural Research Quarterly vol 33 p 1631999
[12] S Hemming E van Os A Dieleman et al ldquoPossibilities ofincreasing production and quality of strawberry fruits andseveral flowers by new blue fluorescent greenhouse filmsrdquo ActaHorticulturae vol 691 pp 225ndash232 2005
[13] E Espı A Salmeron A Fontecha Y Garcıa and A I RealldquoPlastic films for agricultural applicationsrdquo Journal of PlasticFilm and Sheeting vol 22 no 2 pp 85ndash102 2006
[14] W Fang and R C JaoTransplant Production in the 21st Century2000
[15] RMoe S O Grimstad andH R Gisleroslashd ldquoThe use of artificiallight in year round production of greenhouse crops in NorwayrdquoActa Horticulturae vol 711 pp 35ndash42 2006
[16] H-H Kim R M Wheeler J C Sager N C Yorio and GD Goins ldquoLight-emitting diodes as an illumination source forplants a review of research at Kennedy Space Centerrdquo Habita-tion vol 10 no 2 pp 71ndash78 2005
[17] E Ono and H Watanabe ldquoPlant factories blossomrdquo ResourceEngineering amp Technology for Sustainable World vol 13 no 2pp 13ndash14 2006
[18] R C Morrow ldquoLED lighting in horticulturerdquo HortScience vol43 no 7 pp 1947ndash1950 2008
[19] G D Massa H H Kim R M Wheeler and C A MitchellldquoPlant productivity in response to LED lightingrdquo HortSciencevol 43 no 7 pp 1951ndash1956 2008
[20] N Yeh and J-P Chung ldquoHigh-brightness LEDsmdashenergy effi-cient lighting sources and their potential in indoor plant culti-vationrdquo Renewable and Sustainable Energy Reviews vol 13 no8 pp 2175ndash2180 2009
[21] I Vanninen D M Pinto A I Nissinen N S Johansen and LShipp ldquoIn the light of new greenhouse technologies 1 Plant-mediated effects of artificial lighting on arthropods and tritro-phic interactionsrdquo Annals of Applied Biology vol 157 no 3 pp393ndash414 2010
[22] T Bessho E Yoneda J-H Yum et al ldquoNew paradigm inmolecular engineering of sensitizers for solar cell applicationsrdquoJournal of the American Chemical Society vol 131 no 16 pp5930ndash5934 2009
[23] F Mater T H Ghaddar K Walley T DosSantos J R Durrantand B OrsquoRegan ldquoA new ruthenium polypyridyl dye TG6whose performance in dye-sensitized solar cells is surprisinglyclose to that of N719 the lsquodye to beatrsquo for 17 years rdquo Journal ofMaterials Chemistry vol 18 pp 4246ndash4253 2008
[24] M K Nazeeruddin R Humphry-Baker P Liska and MGratzel ldquoInvestigation of sensitizer adsorption and the influ-ence of protons on current and voltage of a dye-sensitized nano-crystalline TiO
2solar cellrdquoThe Journal of Physical Chemistry B
vol 107 no 34 pp 8981ndash8987 2003[25] Y Lee S R Jang R Vittal andK J Kim ldquoDinuclear Ru(II) dyes
for improved performance of dye-sensitized TiO2solar cellsrdquo
New Journal of Chemistry vol 31 no 12 pp 2120ndash2126 2007[26] M K Nazeeruddin F De Angelis S Fantacci et al ldquoCom-
bined experimental and DFT-TDDFT computational study ofphotoelectrochemical cell ruthenium sensitizersrdquo Journal of theAmerican Chemical Society vol 127 no 48 pp 16835ndash168472005
[27] M K Nazeeruddin T Bessho L Cevey et al ldquoA high molarextinction coefficient charge transfer sensitizer and its applica-tion in dye-sensitized solar cellrdquo Journal of Photochemistry andPhotobiology A Chemistry vol 185 no 2-3 pp 331ndash337 2007
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Inorganic ChemistryInternational Journal of
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
International Journal ofPhotoenergy
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Carbohydrate Chemistry
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Advances in
Physical Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom
Analytical Methods in Chemistry
Journal of
Volume 2014
Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
SpectroscopyInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Medicinal ChemistryInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chromatography Research International
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Applied ChemistryJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Theoretical ChemistryJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Spectroscopy
Analytical ChemistryInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Quantum Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Organic Chemistry International
ElectrochemistryInternational Journal of
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CatalystsJournal of
International Journal of Photoenergy 7
structure-function relationshiprdquo Angewandte Chemie Interna-tional Edition vol 44 no 35 pp 5740ndash5744 2005
[5] DKuang PWalter FNuesch et al ldquoCo-sensitization of organicdyes for efficient ionic liquid electrolyte-based dye-sensitizedsolar cellsrdquo Langmuir vol 23 no 22 pp 10906ndash10909 2007
[6] T Renouard R A Fallahpour M K Nazeeruddin et al ldquoNovelruthenium sensitizers containing functionalized hybrid tetra-dentate ligands Synthesis characterization and INDOS anal-ysisrdquo Inorganic Chemistry vol 41 no 2 pp 367ndash378 2002
[7] M K Nazeeruddin P Pechy T Renouard et al ldquoEngineeringof efficient panchromatic sensitizers for nanocrystalline TiO
2-
based solar cellsrdquo Journal of the American Chemical Society vol123 no 8 pp 1613ndash1624 2001
[8] K Chen Y-H Hong Y Chi W-H Liu B-S Chen and P-TChou ldquoStrategic design and synthesis of novel tridentate bipyri-dine pyrazolate coupled Ru(II) complexes to achieve superiorsolar conversion efficiencyrdquo Journal of Materials Chemistry vol19 no 30 pp 5329ndash5335 2009
[9] S Pearson A E Wheldon and P Hadley ldquoRadiation transmis-sion and fluorescence of nine greenhouse cladding materialsrdquoJournal of Agricultural Engineering Research vol 62 no 1 pp61ndash70 1995
[10] C Kittas and A Baille ldquoDetermination of the spectral proper-ties of several greenhouse covermaterials and evaluation of spe-cific parameters related to plant responserdquo Journal of Agricul-tural Engineering Research vol 71 no 2 pp 193ndash202 1998
[11] S Tazawa ldquoEffects of various radiant sources on plant growth(part 1)rdquo Japan Agricultural Research Quarterly vol 33 p 1631999
[12] S Hemming E van Os A Dieleman et al ldquoPossibilities ofincreasing production and quality of strawberry fruits andseveral flowers by new blue fluorescent greenhouse filmsrdquo ActaHorticulturae vol 691 pp 225ndash232 2005
[13] E Espı A Salmeron A Fontecha Y Garcıa and A I RealldquoPlastic films for agricultural applicationsrdquo Journal of PlasticFilm and Sheeting vol 22 no 2 pp 85ndash102 2006
[14] W Fang and R C JaoTransplant Production in the 21st Century2000
[15] RMoe S O Grimstad andH R Gisleroslashd ldquoThe use of artificiallight in year round production of greenhouse crops in NorwayrdquoActa Horticulturae vol 711 pp 35ndash42 2006
[16] H-H Kim R M Wheeler J C Sager N C Yorio and GD Goins ldquoLight-emitting diodes as an illumination source forplants a review of research at Kennedy Space Centerrdquo Habita-tion vol 10 no 2 pp 71ndash78 2005
[17] E Ono and H Watanabe ldquoPlant factories blossomrdquo ResourceEngineering amp Technology for Sustainable World vol 13 no 2pp 13ndash14 2006
[18] R C Morrow ldquoLED lighting in horticulturerdquo HortScience vol43 no 7 pp 1947ndash1950 2008
[19] G D Massa H H Kim R M Wheeler and C A MitchellldquoPlant productivity in response to LED lightingrdquo HortSciencevol 43 no 7 pp 1951ndash1956 2008
[20] N Yeh and J-P Chung ldquoHigh-brightness LEDsmdashenergy effi-cient lighting sources and their potential in indoor plant culti-vationrdquo Renewable and Sustainable Energy Reviews vol 13 no8 pp 2175ndash2180 2009
[21] I Vanninen D M Pinto A I Nissinen N S Johansen and LShipp ldquoIn the light of new greenhouse technologies 1 Plant-mediated effects of artificial lighting on arthropods and tritro-phic interactionsrdquo Annals of Applied Biology vol 157 no 3 pp393ndash414 2010
[22] T Bessho E Yoneda J-H Yum et al ldquoNew paradigm inmolecular engineering of sensitizers for solar cell applicationsrdquoJournal of the American Chemical Society vol 131 no 16 pp5930ndash5934 2009
[23] F Mater T H Ghaddar K Walley T DosSantos J R Durrantand B OrsquoRegan ldquoA new ruthenium polypyridyl dye TG6whose performance in dye-sensitized solar cells is surprisinglyclose to that of N719 the lsquodye to beatrsquo for 17 years rdquo Journal ofMaterials Chemistry vol 18 pp 4246ndash4253 2008
[24] M K Nazeeruddin R Humphry-Baker P Liska and MGratzel ldquoInvestigation of sensitizer adsorption and the influ-ence of protons on current and voltage of a dye-sensitized nano-crystalline TiO
2solar cellrdquoThe Journal of Physical Chemistry B
vol 107 no 34 pp 8981ndash8987 2003[25] Y Lee S R Jang R Vittal andK J Kim ldquoDinuclear Ru(II) dyes
for improved performance of dye-sensitized TiO2solar cellsrdquo
New Journal of Chemistry vol 31 no 12 pp 2120ndash2126 2007[26] M K Nazeeruddin F De Angelis S Fantacci et al ldquoCom-
bined experimental and DFT-TDDFT computational study ofphotoelectrochemical cell ruthenium sensitizersrdquo Journal of theAmerican Chemical Society vol 127 no 48 pp 16835ndash168472005
[27] M K Nazeeruddin T Bessho L Cevey et al ldquoA high molarextinction coefficient charge transfer sensitizer and its applica-tion in dye-sensitized solar cellrdquo Journal of Photochemistry andPhotobiology A Chemistry vol 185 no 2-3 pp 331ndash337 2007
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Inorganic ChemistryInternational Journal of
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
International Journal ofPhotoenergy
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Carbohydrate Chemistry
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Advances in
Physical Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom
Analytical Methods in Chemistry
Journal of
Volume 2014
Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
SpectroscopyInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Medicinal ChemistryInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chromatography Research International
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Applied ChemistryJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Theoretical ChemistryJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Spectroscopy
Analytical ChemistryInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Quantum Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Organic Chemistry International
ElectrochemistryInternational Journal of
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CatalystsJournal of
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Inorganic ChemistryInternational Journal of
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
International Journal ofPhotoenergy
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Carbohydrate Chemistry
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Advances in
Physical Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom
Analytical Methods in Chemistry
Journal of
Volume 2014
Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
SpectroscopyInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Medicinal ChemistryInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chromatography Research International
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Applied ChemistryJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Theoretical ChemistryJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Spectroscopy
Analytical ChemistryInternational Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Quantum Chemistry
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Organic Chemistry International
ElectrochemistryInternational Journal of
Hindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CatalystsJournal of