Permanent polarization and charge distribution in organic light-emitting diodes (OLEDs): Insights from near-infrared charge-modulation spectroscopy of an operating OLED
作者： Alfred P. Marchetti , Terri L. Haskins , Ralph H. Young , Lewis J. Rothberg
DOI: 10.1063/1.4867779
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摘要: Vapor-deposited Alq3 layers typically possess a strong permanent electrical polarization, whereas NPB do not. (Alq3 is tris(8-quinolinolato)aluminum(III); 4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl.) The cause net orientation of the molecules with their large dipole moments. Here we report on consequences for an organic light-emitting diode (OLED) hole-transport layer and electron-transport layer. discontinuous polarization at NPB|Alq3 interface has same effect as sheet immobile negative charge there. It more than compensated by concentration injected holes (NPB+) when OLED running. We discuss implications quantum efficiency drive voltage this others. also speculate possible in photovoltaic devices. NPB+ was measured charge-modulation spectroscopy (CMS) near infrared, where absorption band, supplemented differential-capacitance current-voltage measurements. Unlike CMS visible, method avoids complications from modulation electroluminescence electroabsorption.
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sci-hub.se 参考文章(150)
P. Peumans, S. R. Forrest, Very-high-efficiency double-heterostructure copper phthalocyanine/C60 photovoltaic cells Applied Physics Letters. ,vol. 79, pp. 126- 128 ,(2001) , 10.1063/1.1384001
L. S. Hung, L. R. Zheng, M. G. Mason, Anode modification in organic light-emitting diodes by low-frequency plasma polymerization of CHF3 Applied Physics Letters. ,vol. 78, pp. 673- 675 ,(2001) , 10.1063/1.1331639
P.M. Borsenberger, E.H. Magin, J. Shi, Charge transport in vapor deposited molecular glasses Physica B-condensed Matter. ,vol. 217, pp. 212- 220 ,(1996) , 10.1016/0921-4526(95)00627-3
M. Segal, M. A. Baldo, R. J. Holmes, S. R. Forrest, Z. G. Soos, Excitonic singlet-triplet ratios in molecular and polymeric organic materials Physical Review B. ,vol. 68, pp. 075211- ,(2003) , 10.1103/PHYSREVB.68.075211
Simon J Martin, Geraldine L.B Verschoor, Matthew A Webster, Alison B Walker, The internal electric field distribution in bilayer organic light emitting diodes Organic Electronics. ,vol. 3, pp. 129- 141 ,(2002) , 10.1016/S1566-1199(02)00050-2
Uwe Rau, Reciprocity relation between photovoltaic quantum efficiency and electroluminescent emission of solar cells Physical Review B. ,vol. 76, pp. 085303- ,(2007) , 10.1103/PHYSREVB.76.085303
Youichi Okabayashi, Eisuke Ito, Takashi Isoshima, Hiromi Ito, Masahiko Hara, Negative giant surface potential of peeled Alq3 thin film Thin Solid Films. ,vol. 518, pp. 839- 841 ,(2009) , 10.1016/J.TSF.2009.07.099
P. A. Lane, J. C. deMello, R. B. Fletcher, M. Bernius, Electric field screening in polymer light-emitting diodes Applied Physics Letters. ,vol. 83, pp. 3611- 3613 ,(2003) , 10.1063/1.1623014
Youichi Okabayashi, Eisuke Ito, Takashi Isoshima, Masahiko Hara, Positive Giant Surface Potential of Tris(8-hydroxyquinolinolato) Aluminum (Alq$_{3}$) Film Evaporated onto Backside of Alq$_{3}$ Film Showing Negative Giant Surface Potential Applied Physics Express. ,vol. 5, pp. 055601- ,(2012) , 10.1143/APEX.5.055601
Wenfa Xie, Yi Zhao, Jingying Hou, Shiyong Liu, Spectroscopic Ellipsometry Studies of CuPc and Other Materials for Organic Light-Emitting Devices Japanese Journal of Applied Physics. ,vol. 42, pp. 1466- 1469 ,(2003) , 10.1143/JJAP.42.1466