Silafluorene moieties as promising building blocks for constructing wide-energy-gap host materials of blue phosphorescent organic light-emitting devices  

作　　者：Dongdong Wang Qingqing Liu Yue Yu Yong Wu Xinwen Zhang Hua Dong Lin Ma Guijiang Zhou Bo Jiao Zhaoxin Wu Runfeng Chen 

机构地区：[1]Department of Applied Chemistry, School of Science, Xi'an Jiaotong University [2]Key Laboratory of Organic Electronics and Information Displays [3]Institute of Advanced Materials, School of Electronic and Information Engineering, Nanjing University of Posts and Telecommunications [4]Key Laboratory for Physical Electronics and Devices of the Ministry of Education [5]School of Electronic and Information Engineering,Xi'an Jiaotong University

出　　处：《Science China Chemistry》2015年第6期993-998,共6页中国科学（化学英文版）

基　　金：supported by the Fundamental Research Funds for the Central Universities(08143034);the National Basic Research Program of China(2013CB328705);the National Natural Science Foundation of China(61275034,61106123)

摘　　要：In this article, we reported the synthesis and characterization of a novel silafluorene-based host material, 1,3-bis（5-methyl-5H- dibenzo[b,d]silol-5-yl）benzene （Me-DBSiB）, for blue phosphorescent organic light-emitting devices （PHOLEDs）. The Me- DBSiB was constructed by linking 9-methyl-9-silafluorene units to the phenyl framework through the sp3-hybridized silica atom to maintain high singlet and triplet energy, as well as to enhance thermal and photo-stability. The calculated result shows that the phenyl core does not contribute to both the highest occupied molecular orbital and lowest unoccupied molecular orbital. Wide optical energy gap of 4.1 eV was achieved. When the Me-DBSiB was used as the host and iridium （Ⅲ） bis[（4,6-difluorophenyl）pyridinato-N,C2＇]picolate （Firpic） as the guest, a maximum current efficiency was 14.8 cd/A, lower than the counterpart of 1,3-bis（9-carbazolyl）benzene （28 cd/A）. The unbalanced barrier for electron and hole injection to host layer may be responsible for low efficiency. Even so, our results show that silafluorene moieties are promising building blocks for constructing wide-energy-gap host materials.In this article, we reported the synthesis and characterization of a novel silafluorene-based host material, 1,3-bis(5-methyl-5Hdibenzo[b,d]silol-5-yl)benzene(Me-DBSi B), for blue phosphorescent organic light-emitting devices(PHOLEDs). The MeDBSi B was constructed by linking 9-methyl-9-silafluorene units to the phenyl framework through the sp3-hybridized silica atom to maintain high singlet and triplet energy, as well as to enhance thermal and photo-stability. The calculated result shows that the phenyl core does not contribute to both the highest occupied molecular orbital and lowest unoccupied molecular orbital. Wide optical energy gap of 4.1 e V was achieved. When the Me-DBSi B was used as the host and iridium(III) bis[(4,6-difluorophenyl)pyridinato-N,C2′]picolate(Firpic) as the guest, a maximum current efficiency was 14.8 cd/A, lower than the counterpart of 1,3-bis(9-carbazolyl)benzene(28 cd/A). The unbalanced barrier for electron and hole injection to host layer may be responsible for low efficiency. Even so, our results show that silafluorene moieties are promising building blocks for constructing wide-energy-gap host materials.

关 键 词：silafluorene moiety wide energy gap host materials blue phosphorescence organic light-emitting device 

分 类 号：O621.22[理学—有机化学]