Photovoltaic response of dye-sensitized solar cell using 2′,7′...

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Materials Science in Semiconductor Processing

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n Corrtor Labs

E-mihussein

Pleas10.10

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Photovoltaic response of dye-sensitized solar cell using20,70-dichlorofluorescein as an organic dye

I.S. Yahia a,b,c,n, A.M. Shakra c, M. Fadel c, Hoda S. Hafez d,M.M. Micheal a,b, F. Yakuphanoglu e

a Department of Physics, Center of Excellent for Advanced Materials Research, Faculty of Science, King Khalid University,PO Box 9004, Abha, Saudi Arabiab Nano-Science Lab., Faculty of Education, Ain Shams University, Roxy, Cairo, Egyptc Semiconductor Lab., Faculty of Education, Ain Shams University, Roxy, Cairo, Egyptd Environmental Studies and Research Institute (ESRI), University of Sadat City, Sadat Branch, Egypte Physics Department, Faculty of Science, Firat University, Elazig, Turkey

a r t i c l e i n f o

Keywords:20 ,70-DichlorofluoresceinDSSCTiO2 photoelectrodePhotovoltaic characterizationImpedance spectroscopyNegative capacitance

x.doi.org/10.1016/j.mssp.2014.06.02301/& 2014 Elsevier Ltd. All rights reserved.

esponding author. Present address: Nano-S., Faculty of Education, Ain Shams Universityail addresses: [email protected], [email protected] (I.S. Yahia).

e cite this article as: I.S. Yahia, et16/j.mssp.2014.06.023i

a b s t r a c t

Dye-sensitized solar cell (DSSC) was fabricated by using 20 ,70-dichlorofluorescein as anorganic dye sensitizer (metal free dye). A FTO/titanium dioxide (TiO2) electrode was dippedin a solution of 20 ,70-dichlorofluorescein and covered with another FTO electrode to formdye-sensitized solar cell. Using dyes in the fabrication of solar cells increases the efficiency ofthe solar cell. The photovoltaic and impedance spectroscopy properties of the solar cell wereinvestigated. A beam of light of different intensity was focused on the surface of the DSSC tomeasure the open circuit voltage, the short circuit current, the output power and the fillfactor. The capacitance–voltage, the conductance–voltage, the series resistance–voltagecharacteristics of the solar cell were measured in a wide range of frequency for the firsttime for DSSC applications. Owing to the injection of electrons from the FTO electrode intoTiO2, the capacitance–voltage characteristic shows the behavior from the (þve) to (�ve)capacitance. The photovoltaic of the DSSC can be improved using various organic semi-conductors. Photons striking the dye with enough energy to be absorbed create an excitedstate of the dye, from which an electron can be “injected” directly into the conduction bandof the TiO2 From there it moves by diffusion to the clear anode on top.

& 2014 Elsevier Ltd. All rights reserved.

1. Introduction

Organic photovoltaic cells (OPCS) have been extensivelystudied as a next generation renewable energy sourcebecause of their attractive properties such as low cost offabrication, light weight and easy processing [1–3].

cience&Semiconduc-, Roxy, Cairo, [email protected],

al., Materials Science

Dye-sensitized solar cells (DSSCs) [4] have been inten-sively studied and researched during the last decade as apromising third solar cell generation due to their potentiallow-cost manufacturing process. The main stream of theresearch has been focusing on development of materialswhich would enhance the conversion efficiency, simplifythe production of DSSC and assure their long-lifetime.Titanium dioxide (TiO2) is an n-type wide band gapsemiconductor that absorbs in the ultraviolet region andis transparent for visible light. In a typical DSSC, the dyemolecules are absorbed on the surface of the TiO2 to assurephotoelectric conversion over a board spectral range of the

in Semiconductor Processing (2014), http://dx.doi.org/

www.sciencedirect.com/science/journal/13698001www.elsevier.com/locate/mssphttp://dx.doi.org/10.1016/j.mssp.2014.06.023http://dx.doi.org/10.1016/j.mssp.2014.06.023http://dx.doi.org/10.1016/j.mssp.2014.06.023mailto:[email protected]:[email protected]:[email protected]://dx.doi.org/10.1016/j.mssp.2014.06.023http://dx.doi.org/10.1016/j.mssp.2014.06.023http://dx.doi.org/10.1016/j.mssp.2014.06.023http://dx.doi.org/10.1016/j.mssp.2014.06.023http://dx.doi.org/10.1016/j.mssp.2014.06.023

Fig. 1. Molecular structure of 20 ,70-dichlorofluorescein.

I.S. Yahia et al. / Materials Science in Semiconductor Processing ] (]]]]) ]]]–]]]2

solar spectrum. When the sunlight radiates onto the DSSC,the electrons in the dye molecules (HOMO level) absorbphotons that become exited and jump to unoccupiedupper level (LUMO level). The electrons from the LUMOlevel are then injected into the TiO2 semiconductor con-duction band and pass through the TiO2 layer to thetransparent conductive oxide (TCO) coated glass and to aload. Further, the vacant “HOMO” level is then filled withelectrons supplied by the iodide (I�) ions in the electrolytewhile iodide is oxidized to tri-iodide (I�3 ). Meanwhile theplatinum counter electrode acts as a catalyst for the redoxreaction of the ions in the electrolyte solution and reducesthe tri-iodide back to iodide [4].

Compared with metal complexes, metal-free organicdyes have also attracted considerable attention due to theadvantages of easier preparation and purification, higherstructural flexibility, environ-mental friendliness andavoidance of noble metals. In particular, the design andsynthesis of donor acceptor metal-free organic dyes with awide range of donor groups such as, triphenylamine [5],coumarin [6], indoline [7], carbazole [8], squaraine [9], andphenothiazine (PT) [10], has led to a number of efficientsensitizers for DSSCs.

According to most up-dated research, precisely designedmetal-free organic dyes are able to be highly competitivecandidates for use as photosensitizers in a highly efficientDSSC. A common strategy for the design of highly efficientdonor-π-acceptor (D-π-A) systems is the use of conjugatedlinking groups which can be tethered to the TiO2electrode assurface anchoring groups [11]. Upon light irradiation, intra-molecular photo-induced charge transfer from the donor tothe acceptor is generated and a subsequent electron transferto TiO2 photoanode through the conjugated connecting groupoccurs. The preferential orientation of the dye on the TiO2surface not only improves donor ability at a distance from thephoto-injected electrons, but also diminishes the detrimentalimpact of backward transfer of the electrons [12].

Some organic materials have been confirmed as promisingcandidates for photovoltaic application which include poly(3-hexylthiophene) (P3HT), methanofullerene [6,6]-phenyl C61butyric acid methyl ester (PCBM), metalphthalocyanines(MPCs), buckminsterfullerene (C60), poly(2-methoxy-5-(20-ethyl-hexyloxy)-1,4-phenylenevinylene) (MEH-PPV). How-ever, the performance of these photovoltaic cells has beenlimited due to relatively short excitation diffusion lengths andlow charge carrier mobility of the active layer [13,14].

The improvement of the charge transport properties ofthe semiconductor electrode means reducing the electronrecombination during the diffusion process and thusenhancing the electron collection efficiency of the photo-voltaic cells. While in many cases, this way merely resultsin an increasing of the short-circuit photocurrent density(Isc), the contributions to the increase of open-circuitvoltages (Voc) or fill factor (FF) are often insignificant[15,16]. As another way to enhance the performance of aDSSC, suppression of the charge recombination on the SEIby passivating the surface state of the electrodes not onlyimproves the collection efficiency of electrons, but Voc andFF of the cell also can be enhanced [17,18].

In the present work we have focused on fabrication andcharacterization on 20,70-dichlorofluorescein and its

Please cite this article as: I.S. Yahia, et al., Materials Science10.1016/j.mssp.2014.06.023i

effectiveness on the photovoltaic performance of DSSC.Also, the electrical conduction mechanism under the effectof light, the capacitance–voltage, the conductance–voltage,the series resistance–voltage characteristics of the solarcell were measured in a wide range of frequency for thefirst time for DSSC applications.

2. Experimental technique

2.1. Fabrication of the dye-sensitized solar cell

Fabrication of DSSC was mainly according to a literatureprocedure [19].Titanium dioxide (TiO2) nanoporous (nano-particles) were prepared by the following procedure [20–22]. By adding (10 mL) tetrabutyltitanate to (100 mL)distilled water, a white precipitate will be formed. A glassfrit was used to filter the precipitate then it was washedthree times with distilled water. By adding filter cake to(0.1 M, 160 mL) nitric acid aqueous solution under vigor-ous stirring at 80 1C, the slurry became a translucent blue–white liquid. The resultant colloidal suspension was auto-claved at 200 1C for 12 h to form white milky slurry. Theresultant slurry was concentrated to one fourth of itsoriginal volume, then PEG-20000 (10 wt% slurry) and afew drops of emulsification reagent of Triton X-100 wereadded to form a TiO2 colloid. The TiO2 paste was thendeposited by doctor blade technique on FTO glass and itsactive area is 0.25 cm2. The process was done for threetimes to form a thick TiO2 film with about 9 mm. Finally,the TiO2 Porous film was sintered by firing the conductingglass sheet at 450 1C in air for 30 min.

20,70-Dichlorofluorescein �90% (TLC), crystalline wassupplied from Sigma-Aldrich without further purification.The chemical formula of 20,70-dichlorofluorescein isC20H10Cl2O5 with molecular weight equals 401.20 andmelting point equals 280 1C. The molecular structure of20,70-dichlorofluorescein is shown in Fig. 1. A FTO/titaniumdioxide (TiO2) electrode was dipped in a solution of 20,70-dichlorofluorescein for 24 h to absorb the dye then theelectrode was washed with dry ethanol and lifted at theatmosphere to dry. Another FTO electrode covered withplatinum was prepared. Then a liquid iodide tri-iodideelectrolyte solution was injected between the TiO2 elec-trode and the platinum electrode then the two electrodeswere clipped together. A cyanoacrylate adhesive was usedto prevent the leakage of the electrolyte. Finally the cellwas sealed by using Epoxy resin.

2.1.1. MeasurementsThe photocurrent–voltage (I–V) curves were recorded

by a Keithley 4200-SCS semiconductor characterization


http://dx.doi.org/10.1016/j.mssp.2014.06.023http://dx.doi.org/10.1016/j.mssp.2014.06.023http://dx.doi.org/10.1016/j.mssp.2014.06.023http://dx.doi.org/10.1016/j.mssp.2014.06.023

Fig. 2. ((a) and (b)) 2D and 3D AFM micrographs of TiO2/FTO of1�1 mm2, respectively.

2.8x10-5

2.6x10-5

2.4x10-5

2.2x10-5

2.0x10-5-5

I.S. Yahia et al. / Materials Science in Semiconductor Processing ] (]]]]) ]]]–]]] 3

system. The photovoltaic measurements were performedusing an Small-Area Class-BBA Solar Simulator and thelight intensity was measured using a TM-206 solar powermeter. All the measurements were carried out at roomtemperature in dark and at different illumination levels.The surface morphology of the FTO/TiO2 photo-electrodewas investigated by atomic force microscope (AFM, ParkSystem, XE100) using a non-contact mode.

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.400.0

1.8x101.6x10-5

1.4x10-5

1.2x10-5

1.0x10-5

8.0x10-6

6.0x10-6

4.0x10-6

2.0x10-6

I, (A

)

V, (V)

Fig. 3. The relation between the photocurrent (I) and photovoltage (V)under different illumination intensities for investigated 20 ,70-dichloro-fluorescein DSSC.

3. Results and discussion

3.1. Atomic force microscope (AFM) measurement

The surface morphology of TiO2/FTO was studied byAFM for determining both the gain size and roughness.Fig. 2(a and b) represents 2D and 3D AFM micrographs ofTiO2/FTO with size 1�1 mm2. It is clear that TiO2 consistsof spherical nano-particles. The average particles size are44.437 nm with roughness equals 20.307 nm.


3.2. Photovoltaic parameters of DSSC

The performance of the dye-sensitized solar cell wasevaluated by the current–voltage measurements underdifferent illumination. Fig. 3 depicts the photocurrent–voltage characteristic for 20,70-dichlorofluorescien DSSCunder different illuminations in the range 10 mW/cm2 to120 mW/cm2. The photocurrent is defined as an increaseof the current under light illumination. This is an indica-tion of the generated free carriers by absorbed photons.The phenomenon of photocurrent involves the process ofabsorption of photons (hv) within the depletion layer andthe photo-generation of charge carriers. From Fig. 3, it canbe observed that the photocurrent and photo-voltagevalues are increased with increasing illumination intensi-ties. The short circuit current Isc and open circuit voltageVoc were found to be 0.0172 mA and 0.345 V under100 mW/cm2 illuminations, respectively.

The plot of the electric power versus voltages for 20,70-dichlorofluorescien DSSC device under different intensityof illumination from 10 mW/cm2 to 120 mW/cm2 is shownin Fig. 4. The electric power increases with increasing ofbias voltage and reaches its maximum power and thendecreases until reaches zero voltage values with thefurther increase of the applied voltage. The maximumpower is defined as Pm¼ Im�Vm, where Im is the maximumcurrent and Vm is the maximum Voltage at each illumina-tion intensities. The maximum power point is shifted tothe higher voltages with increasing the incident light asshown in Table 1; the maximum power value indicateshow much the DSSC can deliver its maximum power to anexternal load.

Fig. 5 represent the dependence of open circuit voltageVoc and the short circuit current Isc on the intensities ofillumination L. It is observed from this figure that Vocincreases rapidly then increases slowly by increasing theintensities of illumination until it reaches a maximumvalue for the open circuit voltage at 0.36 V. This meansthat at the lower intensity values, the photovoltaic voltageis only proportional to the light intensity [12]. While Iscincreases approximately linearly with increasing the inten-sities of illumination, and that show the efficiency of the



0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.400

1µ

2µ

3µ

4µ

5µ

P, (W

)

V, (V)

Fig. 4. Plot of the output power versus voltage for 20 ,70-dichloro-fluorescein DSSC.

Table 1Values for maximum power and the corresponding values for the inputvoltage at different illumination intensities.

Illumination Vm (V) Im (A) Pm (W)

10 0.065 2.30E�08 1.50E�0920 0.100 7.35E�08 7.35E�0930 0.126 1.85E�07 2.33E�0840 0.166 3.45E�07 5.73E�0850 0.175 6.00E�07 1.05E�0760 0.209 1.00E�06 2.09E�0770 0.224 1.46E�06 3.27E�0780 0.235 2.00E�06 4.70E�0790 0.245 2.62E�06 6.42E�07

100 0.241 3.19E�06 7.69E�07110 0.250 3.90E�06 9.75E�07120 0.235 4.55E�06 1.07E�06

0 20 40 60 80 1000.0

5.0x10-6

1.0x10-5

1.5x10-5

2.0x10-5

2.5x10-5

IscVoc

L, (mW/cm2)

I sc, (

A)

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

V oc,

(V)

Fig. 5. Dependence of Voc and I sc on the intensities of illumination for20 ,70-dichlorofluorescein DSSC.

0.0 5.0x10-6 1.0x10-5 1.5x10-5 2.0x10-5 2.5x10-50.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

V oc,

(V)

Isc, (A)

Fig. 6. The variation of Voc with Isc for 20 ,70-dichlorofluorescein DSSC.

0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0-6.2

-6.0

-5.8

-5.6

-5.4

-5.2

-5.0

-4.8

-4.6

-4.4

(II)

Ln I s

c, (I s

c in μA

)

Ln L,(L in mw/cm2)

(I)

Fig. 7. Represent the relation lnIsc versus lnL for 20 ,70-dichlorofluoresceinDSSC.


photo-oxidization and regeneration (by the I� =I�3 ions) ofthe absorbed dye molecules. At both lower and higherradiant powers, the short circuit current Isc tends to varylinearly with the power illumination which indicate thatmass transport does not limit to the Isc [23].

In the other hand, there is an exponential relationbetween the short circuit current Isc and the open circuitvoltage Voc as shown in Fig. 6. This relation can be described


as [19,24–26]

Voc ¼ nkTq lnJscJ0þ1

� �; ð1Þ

as J0 is the reverse saturation current density, n is the diodeideality factor, k is the Boltzmann’s constant and q is theelectric charge. From Fig. 6, it is clear that Voc increases withthe increase of Isc and increases with the increasing of lightintensity which can be observed in Figs. 3 and 4.

Fig. 7 shows the relation between lnIsc and lnL for DSSCthis relation can be described by the formula Isc¼kLm.Where m is an exponent, which deduce from the slope ofthis relation. It is observed that the plot indicates twolinear regions. The values of m for the regions (I and II)were calculated and equal 0.73 and 1.306, respectively. Thevalue of m of region (I) is due to the increased of themobility at higher density of carriers [27,28] and field-enhanced dissociation of excitons [29,30]. The decrease inthe exponent m with the higher illumination intensities isdue to the lower photo generated excitons and fewercarriers are dissociated. Also, it indicates that the rate ofrecombination is increased from region (I) to region (II).

The short circuit of the DSSC measured during illumi-nation us the difference between the number of generated



0 20 40 60 80 1000.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

FF

L, (mW/cm2)

Fig. 8. The effect of incident light intensities on FF for 20 ,70-dichloro-fluorescein DSSC.

-4 -3 -2 -1 0 1 2 3 4

0

20n

40n

60n

80n

100n

120n

140n 2 kHz 5 kHz10 kHz 50 kHz

Cap

cita

nce,

(F)

V, (V)

-4 -2 0 2 4

-200p

-100p

0

100p

200p

300p

400p

500p

600p

700p

800p

Cap

acita

nce,

(F)

V, (V)

100 kHz 200 kHz 300 kHz 400 kHz 600 kHz 800 kHz

Fig. 9. (a) The frequency dependence of C–V characteristics at appliedfrequencies range from 2 kHz to 50 kHz and (b) from 100 kHz to 800 kHz.

-4 -2 0 2 4

5m

6m

7m

8m

9m

10m

11m

G, (

S)

V, (V)

2 kHz 5 kHz 10 kHz 50 kHz 100 kHz 200 kHz 300 kHz 400 kHz 600 kHz 800 kHz

Fig. 10. Frequency dependence of normalized conductance G–V for 20 ,70-dichlorofluorescein DSSC.


electrons and the ones that undergo recombination reac-tion. From Fig. 3, it is seen that generation of a photo-current in the DSSC is occurred when incident light isabsorbed throughout the sensitized dye, resulting in ultra-fast electron injection into the conduction band (C.B) ofthe TiO2 [31,32]. The injected electrons move through thenetwork of interconnected oxide particles by a randompath process [33] until they reach the conducting glasssubstance. The oxidized dye is regenerated by rapidelectron transfer from the iodide ions in the electrolytebefore it has time to undergo irreversible bleaching[34,35]. The I�3 ions produced in the generation stepdiffuse the short distance to the platinum-Coated cathode,where they are reduced to iodide ions to complete theregenerative cycle. The dye regeneration step is analogousto the super-sensitization process that is used to photo-graphy to allow the dye molecules to inject electronsrepeatedly without bleaching.

Fig. 8 shows the dependence of the calculated value offill factor (FF) on the incident light intensity L. It is shownthat the FF value increase with increasing the lightintensity until it reached to 0.068 at 80 mW/cm2 illumina-tion and then it the decreases, due to the ohmic losses inthe cell [36]. The poor values of FF value (up to 0.06827)can be attributed to increase the parallel current path [37].

3.2.1. Impedance spectroscopy of the solar cellTo study the cell capacitance profile, it is better to

measure the capacitance–voltage characteristic in a widerange of frequencies. Fig. 9(a and b) depict the relationbetween the capacitance C and bias voltage V at differentfrequencies ranging from 2 kHz to 800 kHz for 20,70-dichlor-ofluorescein DSSC (Coated sensitized TiO2 nanostructure).From this figure it shows that: at first the capacitance isnearly constant then it decreases very slowly then itincreases until it reaches its maximum value with thefurther increase in the applied bias voltage. Fig. 9a showsonly a positive capacitance with increasing frequency from2 kHz to 100 kHz. At 200 kHz the capacitance is negative inthe range from �4 V to �0.3 V then it change to positivecapacitance at V4�0.3 V which represent the transitionfrequency. In DSSCs the origin of negative capacitance


(inductive) is concluded in general that the electronsinjected from the front electrode of fluorine doped tin oxide(FTO) into Titanium dioxide TiO2 [19,28]. The time delaybetween electron injection and the modulation of the holeconcentration leads to the observed inductive behavior [28].

Fig. 10 represents the relation between conductance (G)versus the bias voltage (V) at different frequencies at room



-4 -2 0 2 4100

120

140

160

180

200

220

240

260

280

300

3202 kHz

5 kHz 10 kHz 50 kHz 100 kHz 200 kHz 300 kHz 400 kHz 600 kHz 800 kHz

Rs,

(Ohm

s)

V, (V)

Fig. 11. The frequency dependence of Rs versus V plot for 20 ,70-dichlorofluorescein DSSC.

-4 -2 0 2 4100

200

300

400

500

6002 kHz

5 kHz 10 kHz 50 kHz 100 kHz 200 kHz 300 kHz 400 kHz 600 kHz 800 kHz

Z, (O

hms)

V, (V)

Fig. 12. The frequency dependence of impedance Z versus V plot for 20 ,70-dichlorofluorescein DSSC.

-4 -2 0 2 4-50

-40

-30

-20

-10

0

Thet

a, (θ

)

V, (V)

2 kHz 5 kHz 10 kHz 50 kHz 100 kHz 200 kHz 300 kHz 400 kHz 600 kHz 800 kHz

Fig. 13. The frequency dependence of theta versus V plot for 20 ,70-dichlorofluorescein DSSC.


temperature. In this measurement, when a small ac signalis applied to the semiconductor devices, the semiconduc-tor losses of conductance as a result from the exchange ofmajority carriers between the interface states and majoritycarrier band [29]. From this figure, the conductancedecreases with increasing bias voltage from �4 V toþ4 V. Also, the conductance decreases by increasing theapplied frequency up to 5 kHz then conductance begin toincrease up to 200 kHz then conductance decrease againwith increasing the frequency, this may be due to thechange of the capacitance from the (þve) values to the(�ve) values.

The series resistance values were calculated from themeasured cell capacitance CMA and conductance GMA atdifferent frequencies. Fig. 11. shows the dependence ofseries resistance (Rs) on voltage (V) and frequency. Thesolar cell admittance YMA can be described by the equation[19,30]

YMA ¼ GMAþ jωCMA; ð2Þ

from the admittance the series resistance Rs can becalculated from the following relation:

Rs ¼GMA

G2MAþω2C2MA

!; ð3Þ

where Rs is the real part of the impedance and can bedetermined as a function of biasing voltage at a wide rangeof frequencies from 2 kHz to 900 kHz. It is seen from Fig. 11that the value of the series resistance of the DSSCsdecreases with increasing the applied frequency from2 kHz to 800 kHz at bias voltage range from �4 V to 4 V.Also, Fig. 12 shows the dependence of impedance Z on theapplied frequency at biasing voltage range from �4 V to4 V. From Fig. 12, the impedance decreases by increasingthe applied frequency. This can be explained as follows, atthe lower frequencies; the interface state can follow the acsignal and yield an excess capacitance which depends onthe frequency [30].

While, at the higher frequencies interface states cannotfollow the ac signal. In this case, the contribution of


interface state capacitance to the total capacitance isnegligibly small. Also, it can be told that the decrease ofRs with the increase in frequency is due to the capacitancechange from the (þve) to the (�ve) values, also isfollowed by inverse behavior of both the conductanceand series resistance and the impedance. At last Fig. 13represents the relation between theta (θ) and biasingvoltage at different frequencies. From this figure, it wasfound that at low frequency theta has a negative value andincreases by increasing the applied voltage to reach apositive value at 300 kHz.

4. Conclusion

Photovoltaic properties of 20,70-dichlorofluoresceindye-sensitized solar cell have been investigated by cur-rent–voltage and capacitance–voltage measurements.It was found that the deduced value of the short circuitcurrent density (Isc) equal 0.0172 mA and the open circuitvoltage (Voc) equals 0.345 V. Also from the investigation ofthe capacitance spectroscopy it was found that, the solar




cell capacitance–voltage characteristics exhibit a behaviorfrom the positive capacitance to the negative capacitance.The photovoltaic mechanism of the solar cell is controlledby the process of the recombination.

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Photovoltaic response of dye-sensitized solar cell using 2prime,7prime-dichlorofluorescein as an organic dyeIntroductionExperimental techniqueFabrication of the dye-sensitized solar cellMeasurements

Results and discussionAtomic force microscope (AFM) measurementPhotovoltaic parameters of DSSCImpedance spectroscopy of the solar cell

ConclusionReferences

Photovoltaic response of dye-sensitized solar cell using 2′,7′...

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