Efficient top-emitting white organic light emitting device with an extremely stable chromaticity and viewing-angle  

作　　者：邵茗 郭旭 陈淑芬 范曲立 黄维 

机构地区：[1]Key Laboratory Cultivation Base for Organic Electronics and Information Displays and Institute of Advanced Materials,Nanjing University of Posts and Telecommunications

出　　处：《Chinese Physics B》2012年第10期533-538,共6页中国物理B（英文版）

基　　金：Project supported by the Science Fund of the Ministry of Science and Technology,China (Grant No. 2009CB930600);the National Natural Science Foundation of China (Grants Nos. 60907047,61274065,and 60977024);the Key Project of the Chinese Ministryof Education (Grants Nos. 104246 and 707032);the Research Fund for the Doctoral Program of Higher Education Institutions,China (Grant Nos. 20093223120003 and 20093223110003);the Natural Science Foundation of Jiangsu Province and the Higher Education Institutions of Jiangsu Province,China (Grants Nos. BK2009423,SJ209003,10KJB510013,and 11KJD510003);the Fok Ying-Tong Education Foundation,China (Grant No. 111051);the "Qing Lan" Program of Jiangsu Province and the "Pandeng"Project of Nanjing University of Posts and Telecommunications,China (Grant Nos. NY210015,NY211069,and NY210040)

摘　　要：In this paper,we report on the fabrication of a top-emitting electrophosphorescent p-i-n white organic lightemitting diode on the basis of a low-reflectivity Sm/Ag semi-transparent cathode together with a thickness-optimized ZnS out-coupling layer.With a 24-nm out-coupling layer,the reflectivity of the cathode is reduced to 8% at 492 nm and the mean reflectivity is 24% in the visible area.By introducing an efficient electron blocking layer tris（1phenylpyrazolato,N,C2 ＇）iridium（III）（Ir（ppz） 3） to confine the exciton recombination area,the current efficiency and the colour stability of the device are effectively improved.A white emission with the Ir（ppz） 3 layer exhibits a maximum current efficiency of 9.8 cd/A at 8 V,and the Commission Internationale de L＇Eclairage（CIE） chromaticity coordinates are almost constant during a large voltage change of 6 V-11 V.There is almost no viewing angular dependence in the spectrum when the viewing angle is no more than 45,with a CIE x,y coordinate variation of only（±0.0025,±0.0008）.Even at a large viewing angle（75）,the CIE x,y coordinate change is as small as（±0.0087,±0.0013）.In this paper,we report on the fabrication of a top-emitting electrophosphorescent p-i-n white organic lightemitting diode on the basis of a low-reflectivity Sm/Ag semi-transparent cathode together with a thickness-optimized ZnS out-coupling layer.With a 24-nm out-coupling layer,the reflectivity of the cathode is reduced to 8% at 492 nm and the mean reflectivity is 24% in the visible area.By introducing an efficient electron blocking layer tris（1phenylpyrazolato,N,C2 ＇）iridium（III）（Ir（ppz） 3） to confine the exciton recombination area,the current efficiency and the colour stability of the device are effectively improved.A white emission with the Ir（ppz） 3 layer exhibits a maximum current efficiency of 9.8 cd/A at 8 V,and the Commission Internationale de L＇Eclairage（CIE） chromaticity coordinates are almost constant during a large voltage change of 6 V-11 V.There is almost no viewing angular dependence in the spectrum when the viewing angle is no more than 45,with a CIE x,y coordinate variation of only（±0.0025,±0.0008）.Even at a large viewing angle（75）,the CIE x,y coordinate change is as small as（±0.0087,±0.0013）.

关 键 词：white organic light-emitting diode top-emitting electron blocking layer high efficiency colour stability 

分 类 号：TN383[电子电信—物理电子学]