Optimal Color Stability for White Organic Light …NPB 40nm ITO ITO ITO Al 120nm Al 120nm Al 120nm...

Hindawi Publishing CorporationInternational Journal of PhotoenergyVolume 2013 Article ID 173289 6 pageshttpdxdoiorg1011552013173289

Research ArticleOptimal Color Stability for White Organic Light-Emitting Diode(WOLED) by Using Multiple-Ultra-Thin Layers (MUTL)

Kan-Lin Chen1 Chien-Jung Huang2 Wen-Ray Chen3 Fong-Yi Lin2

Teen-Hang Meen3 and Chih-Chieh Kang4

1 Department of Electronic Engineering Fortune Institute of Technology Kaohsiung 83160 Taiwan2Department of Applied Physics National University of Kaohsiung Kaohsiung 81148 Taiwan3Department of Electronic Engineering National Formosa University Hu-Wei Yunlin 63201 Taiwan4Department of Electro-Optical Engineering Southern Taiwan University of Science and Technology Tainan 71005 Taiwan

Correspondence should be addressed to Kan-Lin Chen klchenfotechedutw and Chien-Jung Huang chiennukedutw

Received 15 September 2013 Accepted 3 October 2013

Academic Editor Liang-Wen Ji

Copyright copy 2013 Kan-Lin Chen et al This 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

The work demonstrates the improvement of color stability for white organic light-emitting diode (WOLED) The devices wereprepared by vacuum deposition on ITO-glass substratesThese guest materials of 561112-tetraphenylnaphthacene (Rubrene) weredeposited in 441015840-bis(22-diphenyl vinyl)-111015840-biphenyl (DPVBi) resulting in an emitting layer Experimental results reveal that theproperties in the multiple-ultra-thin layer (MUTL) are better than those of the emitting layer with a single guest material reachingthe commercial white-light wavelength requirement of 400ndash700 nmThe function of theMUTL is as the light-emitting and trappinglayer The results show that the MUTL has excellent carrier capture effect leading to high color stability of the device at variousapplied voltages The Commissions Internationale De LrsquoEclairage (CIE) coordinate of this device at 3sim7V is few displacement andshows a very slight variation of (0016 0009) The CIE coordinates at a maximal luminance of 9980 cdm2 are (034 033)

1 Introduction

SinceTang andVanslyke first reported on amultilayer organiclight-emitting diode (OLED)OLEDshave beenwidely inves-tigated for their potential application in flat-panel displays[1] OLED has attracted attention owing to its advantageousemission over a wide visible range and its application in flat-panel displays that are driven at low voltage [2ndash4] Further-more the development of white organic light-emitting diode(WOLED) with high brightness and good color purity isnecessary because these devices can be employed not onlyas illumination light source but also as backlight source can-didate for next generation flat-panel displays However theWOLED lighting technology has been extensively studied Toachieve white emission from OLEDs various several meth-ods have been tried to obtain optimalWOLEDs for exampleusing two complementary colors (blue and yellow) multi-layer stack of three primary colors (red green and blue) and

two or three colors of the dye doped into single host material[5ndash7] In the co-deposition process accurately controllingthe evaporation rate and the concentration of the two ormore materials is not easy resulting in its poor performanceHowever non-doped technique can accurately control toavoid the above problems in the fabrication processes

In this work we use nondoped method to fabricateWOLEDs with a multiple-ultra-thin layer (MUTL) structureThe 561112-tetraphenylnaphthacene (Rubrene)material wasused as yellow light sources in MUTL structure In additionthe quantum efficiency of the Rubrene can be close to 100[8ndash11] And then the material of 440-bis (220-diphenylvinyl)-110-biphenyl (DPVBi) is well-known blue fluorescentmaterial However DPVBi is not only emitting but also trans-fering the incomplete energy fromDPVBi to the Rubrene Sofar the study of fluorescence WOLED (FWOLED) based onthe non-doped multiple-ultra-thin layer (MUTL) has not yet

2 International Journal of Photoenergy

C = CH CH = C

N

N N

N

BPhen

NPB

NPB

Rubrene

Rubrene

DPVBi

DPVBi

MoO3

15nm 35nm

20nmDPVBi20nm

10

nmBp

hen

Cs 2

Co 3

Figure 1 The chemical structures of organic materials and the structures of the device in the energy band diagrams of the multilayer(Rubrene = 01 02 and 03 nm) for WOLEDs

been establishedTherefore this paper concerns a simple pro-cess for the non-doped FWOLEDs with a MUTL structureensuring that the improvement of FWOLEDs performancewas highly efficient due to the good capture efficiency ofcharge carrier for the guest material Besides a detailedinvestigation of the transmission mechanism for the MUTLstructure on the electroluminescence (EL) and the colorstability of FWOLEDs is presented

2 Experimental

Figure 1 shows the chemical structures of organic materialsand the structures of the device that are used in this studyIndium tin oxide (ITO) coated glass with a sheet resistanceof approximately 15Ωsq was consecutively cleaned in ultra-sonic bath containing detergent water acetone ethanol anddeionized (DI) water for 20min each and then dried with

International Journal of Photoenergy 3

0 2 4 6 8 10 12 14 160

10

20

30

40

50

60

70

Voltage (V)

Rubrene 01nmRubrene 02nmRubrene 03nm

Curr

ent d

ensit

y (m

Ac

m2)

Figure 2 The current density-voltage (J-V) characteristics of thedevices with various thicknesses of Rubrene layer

a nitrogen (N2) flow All organic layers were sequentially

evaporated onto the ITO coated-glass substrate at high-vacuum (1 times 10minus6 Torr) thermal evaporation Thermal depo-sition rates for organic materials inorganic materials andAl were about 1 Asec 1 Asec and 10 Asec respectivelyThe evaporation rate and thickness of the thin films werecontrolled using a quartz-crystal monitor system (SigmaSID-142) in this work

The active area of the device was 06 cm2 To measurethe properties of the device a voltage was applied by using aKeithley 2400 programmable voltage-current source (Keith-ley SourceMeter 2400 USA) EL spectra and CommissionsInternationale De LrsquoEclairage (CIE) coordination of thedevices were measured by PR655 spectra scan spectrometer(Kollmorgen Instrument PR655 USA) All measurementswere made at room temperature without encapsulating thedevices

3 Results and Discussion

In order to fabricate WOLED we first attempted to obtainthe optimizing thicknesses of Rubrene Generally yellowlight is required as one of the two-color complementary toobtain white light The structure of the device in energyband diagrams of the multilayer for WOLEDs is shown inFigure 1 The thicknesses of Rubrene layer change from 01to 03 nm at fixing other organic layers Figure 2 shows thecurrent density-voltage (J-V) characteristics of the deviceswith various thicknesses of Rubrene layerThe current densityof the devices at 14V whose thicknesses of Rubrene layerare 01sim03 nm are 596 651 and 585mAcm2 respectively Itcan be observed that the device whose thickness of Rubrenelayer is 02 nm has the best J-V characteristics as comparedwith other devices Figure 3 shows the luminance-voltage (L-V) curves of the devices with various thicknesses of Rubrene

0 2 4 6 8 10 12 14 160

200

400

600

800

1000

1200

1400

1600

1800

Voltage (V)

Lum

ines

cenc

e (cd

cm

2)


Figure 3 The luminance-voltage curves of the devices with variousthicknesses of Rubrene layer

300 400 500 600 700 800

EL in

tens

ity (a

u)

Wavelength (nm)


Figure 4 The electroluminescence spectra of the devices with var-ious thicknesses of Rubrene layer at 14V

layer The maximum luminance of devices is 1476 1806and 1566 cdm2 respectively The maximum luminance is1806 cdm2 at 14V and the CIE coordinate is (0270 0286)when Rubrene layer is 02 nm Besides the luminance ofthe device with Rubrene layer of 02 nm is higher thanother devices at the same voltage The phenomenon tellsus that proper thickness of Rubrene layer results in betterluminance for WOLED The device with Rubrene layer of02 nm is ideal because of the best luminance in otherdevices at the same applying voltage However the devicewith proper thickness of Rubrene layer can produce a highluminance Figure 4 shows normalized electroluminescencespectra of the devices at 14V with various thicknesses of


DPVBi 24nm(EML 2)

DPVBi 34nm(EML 1) DPVBi 10nm(EML 1)

NPB 40nm

ITO ITO ITO

Al 120nmAl 120nm

Al 120nm

BPhen Cs2CO3 10nm

BPhen Cs2CO3 10nm

BPhen Cs2CO3 10nm

Device A Device B

DPVBi 6nm(EML 2)

Rubrene 02nmRubrene 02nm

Rubrene 02nm

Rubrene 02nmDPVBi 30nm(EML 2)

NPB 40nm NPB 40nm

MoO3 15nmMoO3 15nm

DPVBi 6nm(EML 3)

Device C

DPVBi 10nm(EML 1)

MoO3 15nm

Figure 5 The structure of WOLEDs

Rubrene layer at 01 02 and 03 nm respectively It is wellknown that the peak wavelengths of the DPVBi layer and theRubrene layer were 436 nm and 556 nm respectively [12 13]It can be observed that light emission of three devices iscomposed of yellow light emission and blue light emission Inaddition it can be found that the devices whose thicknessesof Rubrene layer are 01 and 03 nm all have an EL peakwithout the balances of blue and yellow emission intensityThe device with Rubrene layer of 02 nm has a CIE coordinateof (0270 0286) which lies in about the blue color zoneHowever the device with 02 nm Rubrene layer at 14V hasbetter luminance of 1806 cdm2 In this study the whitelight emission of device consists of the blue emission layerand the yellow emission layer The yellow emission of thedevice was caused by the Rubrene layer which was insertedin the light-emitting layer of DPVBi to form the structureof DPVBi (10 nm EML1)Rubrene (02 nm)DPVBi (30 nmEML2) If the intensity of blue emission was higher thanthat of the yellow emission then the CIE coordinates of thedevice were unstable This is due to the fact that the Rubtenelayer in the device cannot trap enough electrons and holesto generate exciton Therefore optimum complementarycolor of the blue and the yellow emission intensity wasnot achieved According to the results obtained above thebest recombination zone was in the EML2 of the deviceTo achieve an objective of the optimal color stability threestructures of devices as shown in Figure 5 are promoted andfabricated as follows

(a) ITOMolybdenum trioxide (MoO3 15 nm)NN0-

bis-(1-naphthyl)-NN0-biphenyl-110-biphenyl-440-diamine (NPB 40 nm)DPVBi (10 nm)Rubrene

(02 nm)DPVBi (30 nm)47-Diphenyl-110-phenan-throline cesium carbonate (BPhen Cs

2Co3= 4 1

10 nm)Aluminum (Al 120 nm)(b) ITOMoO

3(15 nm)NPB (40 nm)DPVBi (34 nm)

Rubrene (02 nm)DPVBi (6 nm)BPhen Cs2Co3=

4 1 (10 nm)Al (120 nm)(c) ITOMoO


Rubrene (02 nm)DPVBi (24 nm)Rubrene (02 nm)DPVBi (6 nm)BPhen Cs

2Co3= 4 1 (10 nm)Al

(120 nm)

The current density-voltage-luminance characteristics ofdevices AsimC are shown in Figures 6(a) and 6(b) The maxi-mum current density of devices A B and C is 203mAcm2298mAcm2 and 355mAcm2 at 7V respectively It can beseen that current density of device C exceeds the other twodevices at the same voltage This is the reason why deviceC has larger luminance The maximum luminance of thedevices AndashC is 6010 cdm2 7768 cdm2 and 9980 cdm2respectively It can be explained that the holes were accumu-lated at the RubreneEML3 interface and that the electronswere accumulated at the BPhen Cs

2Co3layer indicating

that the electric field can be formed in EML3 The electricfield is favorable for electron injection into the emissionlayer However it is expected that the holes were trappedand confined in the RubreneEML3 interface and electroninjection thus enhanced resulting that an improved carrierbalance was achieved

EL spectra and CIE coordinates during the applied volt-age of 3sim7V are shown in Figure 7 It can be found that thereis a balance or complementary color between blue emissionand yellow emission as shown in Figure 7(a) Besides a purewhite light emission with CIE coordinates of (0331 0332)is observed at the applied voltage of 5V When the applied


1 2 3 4 5 6 70

50

100

150

200

250

300

350

400

Device ADevice BDevice C

Voltage (V)

Curr

ent d

ensit

y (m

Ac

m2)

(a)

1 2 3 4 5 6 70

100020003000400050006000700080009000

1000011000

Device A Device B Device C

Voltage (V)

Lum

ines

cenc

e (cd

cm

2)

(b)

Figure 6 (a) The current density versus bias voltage (J-V) characteristics of devices AsimC (b)The luminance versus voltage (L-V) character-istics of devices AsimC

300 400 500 600 700 800000

002

004

006

008

010

EL in

tens

ity (a

u)

Wavelength (nm)

3V4V5V

6V7V

(a)

00 01 02 03 04 0500

01

02

03

04

05

CIE1931y

CIE 1931 x

3V4V5V

6V7V

(b)

Figure 7 (a) The EL spectra of device C at 3sim7V applied voltage (b) The CIE coordinates of device C at 3sim7V applied voltage

voltage increases from 6V to 7V the CIE coordinates wererespectively (0341 0332) and (0346 0339) and showed alittle change This is owing to the fact that the intensity forthe ratio of blue and yellow emission from EL spectra ofFigure 7(a) is almost the same and about unit Furthermorethis improvement in chromaticity can be attributed to theMUTL structure of the emission layer resulting in a balancein the relative intensity of blue and yellow emission Thusby introducing a MUTL structure in the emission layerthe WOLED has more stable spectra characteristics thanthat of devices A and B with the increase of bias voltage

This is due to the reason that the injection of holes andelectrons was enhanced by the MUTL structure and thatthe MUTL structure can enhance charge carrier trappingin the EML1Rubrene EML2Rubrene and RubreneEML3interfaces And then the enhanced carrier injection wasbecause of electric fields induced by the accumulated carrierbetween interfaces of the MUTL This result is similar tothe result discussed in other literature [14ndash17] In otherwords the excitons formed from electrons and holes canwidely distribute in the entire emission layer As is expectedthe excitons of Rubrene and DPVBi layers will increase and


Table 1 Various characteristics of devices AndashC

Device A Device B Device CTurn-on voltage (V) 35 32 3Operating voltage (V) 41 39 35Maximum luminance (cdm2) 6010 7768 9980Maximum Current density (cdm2) 203 298 355

reach balance indicating that the MUTL can enhance colorstability of CIE coordinates and chromaticity of pure whiteemission However the displacement of the CIE coordinatesduring the applied voltage of 3sim7V is almost null

All the above data can be summarized in Table 1 FromTable 1 it is found that the MUTL structure can enhancecolor stability of CIE coordinates and chromaticity of purewhite emission Furthermore these results show that a highluminance can be achieved with improved carrier balance inthe emission zone Besides the operating voltage of deviceC is lower than that of other devices due to the presence oftheMUTL structure resulting inmore electron injection andbalance

4 Conclusions

In summary white light emission was achieved by insertingtheMUTL structure in the emission layer ofWOLED Experi-mental results reveal that the properties in themultiple-ultra-thin layer (MUTL) are better than those of the emitting layerwith a single guestmaterialThe carrier trapping of theMUTLstructure can more effectively confine electrons and holes inthe emission layer Consequently the excitons of Rubrene andDPVBi layerswill increase and reach balance that is there is abalance or complementary color in blue emission and yellowemission resulting in good color stability characteristics ofWOLED at various applied voltages A pure white emissionCIE coordinates of (0331 0332) can be obtained and show alittle change at the applied voltage of 3sim7V It is demonstratedthat EL emission is less dependent on the applied voltageThus the carrier recombination zone must be properlycontrolled by limiting the exciton zone to prevent the mixingof colors However device with a MUTL structure increasedcarrier tapping probability to improve carrier recombinationand luminous efficiency

Acknowledgment

This work was partially supported by the National ScienceCouncil of the Republic of China under Contract no NSC102-2221-E-390-019-MY2

References

[1] C W Tang and S A Vanslyke ldquoOrganic electroluminescentdiodesrdquo Applied Physics Letters vol 51 no 12 pp 913ndash915 1987

[2] C J Huang T H Meen S L Wu and C C Kang ldquoImprove-ment of color purity and electrical characteristics by co-dopingmethod for flexible red-light organic light emitting devicesrdquoDisplays vol 30 no 4-5 pp 164ndash169 2009

[3] Y Sun N C Giebink H Kanno B Ma M E Thompson andS R Forrest ldquoManagement of singlet and triplet excitons forefficient white organic light-emitting devicesrdquo Nature vol 440no 7086 pp 908ndash912 2006

[4] C J Huang C C Kang T C Lee W R Chen and T HMeen ldquoImproving the color purity and efficiency of blue organiclight-emitting diodes (BOLED) by adding hole-blocking layerrdquoJournal of Luminescence vol 129 no 11 pp 1292ndash1297 2009

[5] J Kido H Shionota and K Nagai ldquoSingleminuslayer whitelightminusemitting organic electroluminescent devices based ondyeminusdispersed poly(N-vinylcarbazole)rdquoApplied Physics Lettersvol 67 no 16 pp 2281ndash2283 1995

[6] K Okumoto H Kanno Y Hamada H Takahashi and KShibata ldquoHigh efficiency red organic light-emitting devicesusing tetraphenyldibenzoperiflanthene-doped rubrene as anemitting layerrdquo Applied Physics Letters vol 89 no 1 Article ID013502 2006

[7] G Li and J Shinar ldquoCombinatorial fabrication and stud-ies of bright white organic light-emitting devices based onemission from rubrene-doped 441015840-bis(221015840-diphenylvinyl)-111015840-biphenylrdquo Applied Physics Letters vol 83 no 26 pp 5359ndash53612003

[8] H Mattoussi H Murata C D Merritt Y Iizumi J Kidoand Z H Kafafi ldquoPhotoluminescence quantum yield of pureand molecularly doped organic solid filmsrdquo Journal of AppliedPhysics vol 86 no 5 pp 2642ndash2650 1999

[9] Y-M Wang F Teng Z Xu Y-B Hou S-Y Yang and X-RXu ldquoTrap effect of an ultrathin DCJTB layer in organic light-emitting diodesrdquo Materials Chemistry and Physics vol 92 no2-3 pp 291ndash294 2005

[10] MMatsumura andT Furukawa ldquoEfficient electroluminescencefrom a rubrene sub-monolayer inserted between electron- andhole-transport layersrdquo Japanese Journal of Applied Physics 1 vol40 no 5 pp 3211ndash3214 2001

[11] T Li X Li W Li et al ldquoTunable red emission by incorporationof a rubrene derivative in p-type and n-type hosts in organiclight emitting devicesrdquo Thin Solid Films vol 517 no 16 pp4629ndash4632 2009

[12] C-J Huang T-H Meen K-C Liao and Y-K Su ldquoThe mech-anism of efficiency enhancement with proper thickness ofDPVBi layer for blue organic light-emitting devices (BOLED)rdquoJournal of Physics and Chemistry of Solids vol 70 no 3-4 pp765ndash768 2009

[13] Q Xue S Zhang G Xie et al ldquoEfficient fluorescent whiteorganic light-emitting devices based on a ultrathin 561112-tetraphenylnaphthacene layerrdquo Solid-State Electronics vol 57no 1 pp 35ndash38 2011

[14] L Li J Yu X Tang T Wang W Li and Y Jiang ldquoEfficientbright white organic light-emitting diode based on non-dopedultrathin 561112-tetraphenylnaphthacene layerrdquo Journal ofLuminescence vol 128 no 11 pp 1783ndash1786 2008

[15] X Tang J Yu L Li L Zhang andY Jiang ldquoWhite organic light-emitting diodes with improved performance using phosphores-cent sensitizer and ultrathin fluorescent emitterrdquo Displays vol30 no 3 pp 123ndash127 2009

[16] S-H Yang B-C Hong and S-F Huang ldquoLuminescenceenhancement and emission color adjustment of white organiclight-emitting diodes with quantum-well-like structuresrdquo Jour-nal of Applied Physics vol 105 no 11 Article ID 113105 2009

[17] ZMa J Yu L Li and Y Jiang ldquoNon-dopedwhite organic light-emitting diodes consisting of three primary colors based on abipolar emitterrdquo Displays vol 33 no 1 pp 42ndash45 2012

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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

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Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of


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Medicinal ChemistryInternational Journal of


Chromatography Research International


Applied ChemistryJournal of



Theoretical ChemistryJournal of


Journal of

Spectroscopy

Analytical ChemistryInternational Journal of


Journal of


Quantum Chemistry


Organic Chemistry International

ElectrochemistryInternational Journal of



CatalystsJournal of


C = CH CH = C

N

N N

N

BPhen

NPB

NPB

Rubrene

Rubrene

DPVBi

DPVBi

MoO3

15nm 35nm

20nmDPVBi20nm

10

nmBp

hen

Cs 2

Co 3

Figure 1 The chemical structures of organic materials and the structures of the device in the energy band diagrams of the multilayer(Rubrene = 01 02 and 03 nm) for WOLEDs

been establishedTherefore this paper concerns a simple pro-cess for the non-doped FWOLEDs with a MUTL structureensuring that the improvement of FWOLEDs performancewas highly efficient due to the good capture efficiency ofcharge carrier for the guest material Besides a detailedinvestigation of the transmission mechanism for the MUTLstructure on the electroluminescence (EL) and the colorstability of FWOLEDs is presented

2 Experimental

Figure 1 shows the chemical structures of organic materialsand the structures of the device that are used in this studyIndium tin oxide (ITO) coated glass with a sheet resistanceof approximately 15Ωsq was consecutively cleaned in ultra-sonic bath containing detergent water acetone ethanol anddeionized (DI) water for 20min each and then dried with


0 2 4 6 8 10 12 14 160

10

20

30

40

50

60

70

Voltage (V)


Curr

ent d

ensit

y (m

Ac

m2)







0 2 4 6 8 10 12 14 160

200

400

600

800

1000

1200

1400

1600

1800

Voltage (V)

Lum

ines

cenc

e (cd

cm

2)



300 400 500 600 700 800

EL in

tens

ity (a

u)

Wavelength (nm)





DPVBi 24nm(EML 2)


NPB 40nm

ITO ITO ITO

Al 120nmAl 120nm

Al 120nm

BPhen Cs2CO3 10nm

BPhen Cs2CO3 10nm

BPhen Cs2CO3 10nm

Device A Device B

DPVBi 6nm(EML 2)


Rubrene 02nm


NPB 40nm NPB 40nm

MoO3 15nmMoO3 15nm

DPVBi 6nm(EML 3)

Device C

DPVBi 10nm(EML 1)

MoO3 15nm






2Co3= 4 1







2Co3= 4 1 (10 nm)Al

(120 nm)






1 2 3 4 5 6 70

50

100

150

200

250

300

350

400


Voltage (V)

Curr

ent d

ensit

y (m

Ac

m2)

(a)

1 2 3 4 5 6 70

100020003000400050006000700080009000

1000011000


Voltage (V)

Lum

ines

cenc

e (cd

cm

2)

(b)


300 400 500 600 700 800000

002

004

006

008

010

EL in

tens

ity (a

u)

Wavelength (nm)

3V4V5V

6V7V

(a)

00 01 02 03 04 0500

01

02

03

04

05

CIE1931y

CIE 1931 x

3V4V5V

6V7V

(b)









4 Conclusions


Acknowledgment


References



























Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


0 2 4 6 8 10 12 14 160

10

20

30

40

50

60

70

Voltage (V)


Curr

ent d

ensit

y (m

Ac

m2)







0 2 4 6 8 10 12 14 160

200

400

600

800

1000

1200

1400

1600

1800

Voltage (V)

Lum

ines

cenc

e (cd

cm

2)



300 400 500 600 700 800

EL in

tens

ity (a

u)

Wavelength (nm)





DPVBi 24nm(EML 2)


NPB 40nm

ITO ITO ITO

Al 120nmAl 120nm

Al 120nm

BPhen Cs2CO3 10nm

BPhen Cs2CO3 10nm

BPhen Cs2CO3 10nm

Device A Device B

DPVBi 6nm(EML 2)


Rubrene 02nm


NPB 40nm NPB 40nm

MoO3 15nmMoO3 15nm

DPVBi 6nm(EML 3)

Device C

DPVBi 10nm(EML 1)

MoO3 15nm






2Co3= 4 1







2Co3= 4 1 (10 nm)Al

(120 nm)






1 2 3 4 5 6 70

50

100

150

200

250

300

350

400


Voltage (V)

Curr

ent d

ensit

y (m

Ac

m2)

(a)

1 2 3 4 5 6 70

100020003000400050006000700080009000

1000011000


Voltage (V)

Lum

ines

cenc

e (cd

cm

2)

(b)


300 400 500 600 700 800000

002

004

006

008

010

EL in

tens

ity (a

u)

Wavelength (nm)

3V4V5V

6V7V

(a)

00 01 02 03 04 0500

01

02

03

04

05

CIE1931y

CIE 1931 x

3V4V5V

6V7V

(b)









4 Conclusions


Acknowledgment


References



























Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


DPVBi 24nm(EML 2)


NPB 40nm

ITO ITO ITO

Al 120nmAl 120nm

Al 120nm

BPhen Cs2CO3 10nm

BPhen Cs2CO3 10nm

BPhen Cs2CO3 10nm

Device A Device B

DPVBi 6nm(EML 2)


Rubrene 02nm


NPB 40nm NPB 40nm

MoO3 15nmMoO3 15nm

DPVBi 6nm(EML 3)

Device C

DPVBi 10nm(EML 1)

MoO3 15nm






2Co3= 4 1







2Co3= 4 1 (10 nm)Al

(120 nm)






1 2 3 4 5 6 70

50

100

150

200

250

300

350

400


Voltage (V)

Curr

ent d

ensit

y (m

Ac

m2)

(a)

1 2 3 4 5 6 70

100020003000400050006000700080009000

1000011000


Voltage (V)

Lum

ines

cenc

e (cd

cm

2)

(b)


300 400 500 600 700 800000

002

004

006

008

010

EL in

tens

ity (a

u)

Wavelength (nm)

3V4V5V

6V7V

(a)

00 01 02 03 04 0500

01

02

03

04

05

CIE1931y

CIE 1931 x

3V4V5V

6V7V

(b)









4 Conclusions


Acknowledgment


References



























Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


1 2 3 4 5 6 70

50

100

150

200

250

300

350

400


Voltage (V)

Curr

ent d

ensit

y (m

Ac

m2)

(a)

1 2 3 4 5 6 70

100020003000400050006000700080009000

1000011000


Voltage (V)

Lum

ines

cenc

e (cd

cm

2)

(b)


300 400 500 600 700 800000

002

004

006

008

010

EL in

tens

ity (a

u)

Wavelength (nm)

3V4V5V

6V7V

(a)

00 01 02 03 04 0500

01

02

03

04

05

CIE1931y

CIE 1931 x

3V4V5V

6V7V

(b)









4 Conclusions


Acknowledgment


References



























Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of






4 Conclusions


Acknowledgment


References



























Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of










Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of

Optimal Color Stability for White Organic Light …NPB 40nm ITO ITO ITO Al 120nm Al 120nm Al 120nm...

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Transcript of Optimal Color Stability for White Organic Light …NPB 40nm ITO ITO ITO Al 120nm Al 120nm Al 120nm...