Please wait a minute...
Chin. Phys. B, 2015, Vol. 24(2): 024222    DOI: 10.1088/1674-1056/24/2/024222
ELECTROMAGNETISM, OPTICS, ACOUSTICS, HEAT TRANSFER, CLASSICAL MECHANICS, AND FLUID DYNAMICS Prev   Next  

Exciplex formation and electroluminescent absorption in ultraviolet organic light-emitting diodes

Zhang Qi (张琪)a, Zhang Hao (张浩)a, Zhang Xiao-Wen (张小文)b, Xu Tao (徐韬)a, Wei Bin (魏斌)a
a School of Materials Science and Engineering & Key Laboratory of Advanced Display and System Applications, Ministry of Education, Shanghai University, Shanghai 200072, China;
b Guangxi Key Laboratory of Information Materials, Guilin University of Electronic Technology, Guilin 541004, China
Abstract  We investigated the formation of exciplex and electroluminescent absorption in ultraviolet organic light-emitting diodes (UV OLEDs) using different heterojunction structures. It is found that an energy barrier of over 0.3 eV between the emissive layer (EML) and adjacent transport layer facilitates exciplex formation. The electron blocking layer effectively confines electrons in the EML, which contributes to pure UV emission and enhances efficiency. The change in EML thickness generates tunable UV emission from 376 nm to 406 nm. In addition, the UV emission excites low-energy organic function layers and produces photoluminescent emission. In UV OLED, avoiding the exciplex formation and averting light absorption can effectively improve the purity and efficiency. A maximum external quantum efficiency of 1.2% with a UV emission peak of 376 nm is realized.
Keywords:  exciplex      tunable UV emission      electroluminescent absorption  
Received:  02 June 2014      Revised:  14 July 2014      Accepted manuscript online: 
PACS:  42.70.Nq (Other nonlinear optical materials; photorefractive and semiconductor materials)  
  42.25.Gy (Edge and boundary effects; reflection and refraction)  
  42.25.Bs (Wave propagation, transmission and absorption)  
Fund: Project supported by the National Natural Science Foundation of China (Grant Nos. 61136003 and 61275041) and the Guangxi Provincial Natural Science Foundation, China (Grant No. 2012GXNSFBA053168).
Corresponding Authors:  Zhang Xiao-Wen, Wei Bin     E-mail:  zhang-xiaowen@163.com;bwei@shu.edu.cn

Cite this article: 

Zhang Qi (张琪), Zhang Hao (张浩), Zhang Xiao-Wen (张小文), Xu Tao (徐韬), Wei Bin (魏斌) Exciplex formation and electroluminescent absorption in ultraviolet organic light-emitting diodes 2015 Chin. Phys. B 24 024222

[1] Bai J J, Wu X M, Hua Y L, Mu X, Bi W T, Su Y J, Jiao Z Q, Shen L Y, Yin S G and Zheng J J 2013 Chin. Phys. B 22 047806
[2] Wen S W, Lee M T and Chen C H 2005 J. Display Technology 1 90
[3] Su S J, Gonmori E, Sasabe H and Kido J 2008 Adv. Mater. 20 4189
[4] Kostov Y, Albano C R and Rao G 2000 Biotechnol. Bioeng. 70 473
[5] Sipior J, Carter G M, Lakowicz J R and Rao G 1997 Rev. Sci. Instrum. 68 2666
[6] Chao T C, Lin Y T, Yang C Y, Hung T S, Chou H C, Wu C C and Wong K T 2005 Adv. Mater. 17 992
[7] Yang Y, Cohn P, Eom S H, Abboud K A, Castellano R K and Xue J 2013 J. Mater. Chem. C 1 2867
[8] Wong K T, Wang C F, Chou C H, Su Y O, Lee G H and Peng S M 2002 Org. Lett. 4 4439
[9] Patel D G, Ohnishi Y, Yang Y, Eom S H, Farley R T, Graham K R, Xue J, Hirata S, Schanze K S and Reynolds J R 2011 J. Polym. Sci. Part B: Polym. Phys. 49 557
[10] Matsushima T and Adachi C 2008 J. Appl. Phys. 103 034501
[11] Mu X, Wu X M, Hua Y L, Jiao Z Q, Shen L Y, Su Y J, Bai J J, Bi W T, Yin S G and Zheng J J 2013 Chin. Phys. B 22 027805
[12] Lu F P, W Q and Zhou X 2013 Chin. Phys. B 22 037202
[13] Wu C I, Lin C T, Lee G R, Cho T Y, Wu C C and Pi T W 2009 J. Appl. Phys. 105 033717
[14] Lim J, Park J and Yeom G 2013 Curr. Appl. Phys. 13 1037
[15] Kroger M, Hamwi S, Meyer J, Riedl T, Kowalsky W and Kahn A 2009 Appl. Phys. Lett. 95 123301
[16] Kr Ger M, Hamwi S, Meyer J, Riedl T, Kowalsky W and Kahn A 2009 Org. Electron. 10 932
[17] Hamwi S, Meyer J, Winkler T, Riedl T and Kowalsky W 2009 Appl. Phys. Lett. 94 253307
[18] Lee J H, Leem D S, Kim H J and Kim J J 2009 Appl. Phys. Lett. 94 123306
[19] Li R, Fan W, Tiag G, et al. 2010 Nature 463 311
[20] Shin W J, Lee J Y, Kim J C, Yoon T H, Kim T S and Song O K 2008 Org. Electron. 9 333
[21] Matsushima T, Kinoshita Y and Murata H 2007 Appl. Phys. Lett. 91 253504
[22] Castellani M and Berner D 2007 J. Appl. Phys. 102 024509
[1] Highly efficient blue fluorescent OLEDs with doped double emitting layers based on p–n heterojunctions
Su Yue-Ju(苏跃举), Wu Xiao-Ming(吴晓明), Hua Yu-Lin(华玉林), Shen Li-Ying(申利莹), Jiao Zhi-Qiang(焦志强), Dong Mu-Sen(董木森), and Yin Shou-Gen(印寿根). Chin. Phys. B, 2012, 21(5): 058503.
[2] Exciplex elimination in an organic light-emitting diode based on a fluorene derivative by inserting 4,4'-N,N'-dicarbazole-biphenyl into donor/acceptor interface
Zhang Wei(张巍), Yu Jun-Sheng(于军胜), Huang Jiang(黄江), Jiang Ya-Dong(蒋亚东), Zhang Qing(张清), and Cao Kang-Li(曹康丽). Chin. Phys. B, 2010, 19(4): 047802.
No Suggested Reading articles found!