Enhancing the efficiency of simplified red phosphorescent organic light emitting diodes by exciton harvesting

被引：59

作者：

Chang, Y-L ^{[1
]}

Wang, Z. B. ^{[1
]}

Helander, M. G. ^{[1
]}

Qiu, J. ^{[1
]}

Puzzo, D. P. ^{[1
]}

Lu, Z. H. ^{[1
]}

机构：

[1] Univ Toronto, Dept Mat Sci & Engn, Toronto, ON M5S 3E4, Canada

来源：

ORGANIC ELECTRONICS | 2012年 / 13卷 / 05期

基金：

加拿大自然科学与工程研究理事会;

关键词：

Phosphorescent organic light emitting diodes; Energy transfer; Exciton harvesting; Carrier trapping; Co-doping; HIGHLY EFFICIENT; QUANTUM EFFICIENCY; TRANSIENT ANALYSIS; IRIDIUM COMPLEXES; ELECTROPHOSPHORESCENCE; GREEN; HOST; BLUE; CARRIER; DEVICES;

D O I：

10.1016/j.orgel.2012.01.026

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

High efficiency red phosphorescent organic light emitting diode (PHOLED) employing co-doped green emitting molecule bis(2-phenylpyridine)(acetylacetonate)iridium(III) [Ir(ppy)(2)(acac)] and red emitting molecule bis(2-methyldibenzo[f,h]quinoxaline)(acetylacetonate)iridium(III) [Ir(MDQ)(2)(acac)] into 4,4'-bis(carbazol-9-yl)biphenyl (CBP) host in a simplified wide-bandgap platform is demonstrated. The green molecule is shown to function as an exciton harvester that traps carriers to form excitons that are then efficiently transferred to the Ir(MDQ)(2)(acac) by triplet-to-triplet Dexter energy transfer, thereby significantly enhancing red emission. In particular, a maximum current efficiency of 37.0 cd/A and external quantum efficiency (EQE) of 24.8% have been achieved without additional out-coupling enhancements. Moreover, a low efficiency roll-off with the EQE remaining as high as 20.8% at a high luminance of 5000 cd/m(2) is observed. (C) 2012 Elsevier B.V. All rights reserved.

引用

页码：925 / 931

页数：7

共 43 条

[31] Solution Processed Red Phosphorescent Organic Light-Emitting Diodes with Green Phosphorescent Ir Sensitizer [J].

Seo, Ji Hyun ;

Choi, Eun Young ;

Kim, Hoe Min ;

Kim, Young Kwan ;

Kim, Seul Ong ;

Lee, Kum Hee ;

Yoon, Seung Soo ;

Je, Jong-Tae .

MOLECULAR CRYSTALS AND LIQUID CRYSTALS, 2011, 538 :91-97

[32] Thin-film transistor as a probe to study carrier transport in amorphous organic semiconductors [J].

So, Shu K. ;

Choi, Wing H. ;

Cheung, Chi H. .

JOURNAL OF PHOTONICS FOR ENERGY, 2011, 1

[33] Highly Efficient Organic Blue-and White-Light-Emitting Devices Having a Carrier- and Exciton-Confining Structure for Reduced Efficiency Roll-Off [J].

Su, Shi-Jian ;

Gonmori, Eisuke ;

Sasabe, Hisahiro ;

Kido, Junji .

ADVANCED MATERIALS, 2008, 20 (21) :4189-+

[34] RGB Phosphorescent Organic Light-Emitting Diodes by Using Host Materials with Heterocyclic Cores: Effect of Nitrogen Atom Orientations [J].

Su, Shi-Jian ;

Cai, Chao ;

Kido, Junji .

CHEMISTRY OF MATERIALS, 2011, 23 (02) :274-284

[35] Rapid intersystem crossing in highly phosphorescent iridium complexes [J].

Tang, KC ;

Liu, KL ;

Chen, IC .

CHEMICAL PHYSICS LETTERS, 2004, 386 (4-6) :437-441

[36] Tuning the Optoelectronic Properties of Carbazole/Oxadiazole Hybrids through Linkage Modes: Hosts for Highly Efficient Green Electrophosphorescence [J].

Tao, Youtian ;

Wang, Qiang ;

Yang, Chuluo ;

Zhong, Cheng ;

Zhang, Kai ;

Qin, Jingui ;

Ma, Dongge .

ADVANCED FUNCTIONAL MATERIALS, 2010, 20 (02) :304-311

[37] Homoleptic cyclometalated iridium complexes with highly efficient red phosphorescence and application to organic light-emitting diode [J].

Tsuboyama, A ;

Iwawaki, H ;

Furugori, M ;

Mukaide, T ;

Kamatani, J ;

Igawa, S ;

Moriyama, T ;

Miura, S ;

Takiguchi, T ;

Okada, S ;

Hoshino, M ;

Ueno, K .

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 2003, 125 (42) :12971-12979

[38] Highly efficient, low-voltage phosphorescent organic light-emitting diodes using an iridium complex as the host material [J].

Tsuzuki, Toshimitsu ;

Tokito, Shizuo .

ADVANCED MATERIALS, 2007, 19 (02) :276-+

[39] Organic light-emitting diodes based on charge-neutral RuII phosphorescent emitters [J].

Tung, YL ;

Lee, SW ;

Chi, Y ;

Chen, LS ;

Shu, CF ;

Wu, FI ;

Carty, AJ ;

Chou, PT ;

Peng, SM ;

Lee, GM .

ADVANCED MATERIALS, 2005, 17 (08) :1059-+

[40] Pt(II) complex based phosphorescent organic light emitting diodes with external quantum efficiencies above 20% [J].

Wang, Z. B. ;

Helander, M. G. ;

Hudson, Z. M. ;

Qiu, J. ;

Wang, S. ;

Lu, Z. H. .

APPLIED PHYSICS LETTERS, 2011, 98 (21)

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