The effect of spacer in hybrid white organic light emitting diodes  

作　　者：Baiquan Liu Miao Xu Hong Tao Yueju Su Dongyu Gao Jianhua Zou Linfeng Lan Junbiao Peng 

机构地区：[1]Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology [2]New Vision Opto-Electronic Technology Co., Ltd

出　　处：《Chinese Science Bulletin》2014年第25期3090-3097,共8页

基　　金：supported by the National BasicResearch Program of China(2009CB623604);the National NaturalScience Foundation of China(61204087,51173049,U0634003,61036007,and 60937001);Fundamental Research Funds for the Central Universities(2011ZB0002,2011ZM0009);China Postdoctoral Science Foundation(2013M531841)

摘　　要：Two kinds of highly efficient,bright hybrid white organic light emitting diodes have been fabricated by utilizing ambipolar material 4,4-N,N-dicarbazolebiphenyl(CBP)and unipolar material N,N0-di(naphthalene-1-yl)-N,N0-diphenyl-benzidine(NPB)as the spacer,respectively.By adjusting the thickness of spacers together with effectively utilizing combinations of exciton-harnessed orangephosphorescence/blue-fluorescence,the current efficiency of optimal device with CBP spacer and device with NPB spacer are 31.0 and 38.9 cd/A,the maximum power efficiency are 23.9 and 29.1 lm/W,the maximum brightness are 87,249 and 75,501 cd/m2,and the Commission Internationale de l’Eclairage(CIE)coordinates are(0.42,0.43)and(0.47,0.44)at a voltage of 11 V,respectively.Furthermore,systematic investigations focused on the effects of spacers on device performance have been performed.By virtue of the multifunctional spacer,energy transfer between the phosphorescent and fluorescent emitters can be avoided while the carriers still can pass through this spacer bridge,which is important to realize such high device performance.In addition,a novel concept that both ambipolar materials and unipolar materials can be the promising candidates for spacers has been proposed if the thickness of spacers with high triplet energy is optimized.Two kinds of highly efficient, bright hybrid white organic light emitting diodes have been fabricated by utilizing ambipolar material 4,4-N,N-dicarbazolebiphenyl （CBP） and unipolar material N,N′-di（naphthalene-l-yl）- N,N′-diphenyl-benzidine （NPB） as the spacer, respectively. By adjusting the thickness of spacers together with effec- tively utilizing combinations of exciton-harnessed orangephosphorescence/blue-fluorescence, the current efficiency of optimal device with CBP spacer and device with NPB spacer are 31.0 and 38.9 cd/A, the maximum power efficiency are 23.9 and 29.1 lm/W, the maximum brightness are 87,249 and 75,501 cd/m2, and the Commission Inter- nationale de l＇Eclairage （CIE） coordinates are （0.42, 0.43） and （0.47, 0.44） at a voltage of 11 V, respectively. Furthermore, systematic investigations focused on the effects of spacers on device performance have been performed. By virtue of the multifunctional spacer, energy transfer between the phosphorescent and fluorescent emitters can be avoided while the carriers still can pass through this spacer bridge, which is important to realize such high device performance. In addition, a novel concept that both ambipolar materials and unipolar materials can be the promising candidates for spacers has been proposed if the thickness of spacers with high triplet energy is optimized.

关 键 词：有机发光二极管 混合 隔离物 极性材料 器件性能 能量转移 蓝色荧光 有效利用 

分 类 号：TN312.8[电子电信—物理电子学] TQ051.72[化学工程]