Efficient red phosphorescent OLEDs based on the energy transfer from interface exciplex: the critical role of constituting molecules  

作　　者：Xiaozeng Song Dongdong Zhang Tianyu Huang Minghan Cai Lian Duan 

机构地区：[1]Key Laboratory of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry,Tsinghua University

出　　处：《Science China Chemistry》2018年第7期836-843,共8页中国科学（化学英文版）

基　　金：supported by the National Key Basic Research and Development Program of China (2016YFB041003, 2016YFB0400702);the National Basic Research Program of China (2015CB655002);the National Natural Science Foundation of China (51525304, U1601651)

摘　　要：A novel acceptor material,9-(4′-(4,6-diphenyl-1,3,5-triazin-2-yl)-[1,1′-biphenyl]-3-yl)-9H-carbazole(o-DTPPC)was developed to form interface exciplex with commonly used donors,to maximize the performances of red phosphorescent organic light emitting diodes(PHOLEDs).It is found that the exciplex involving 4,4′-(cyclohexane-1,1-diyl)bis(N,N-di-p-tolylaniline)(TAPC)exhibits the most significant thermally activated delayed fluorescence(TADF)property,derived from the high triplet energy level as well as strong hole-transporting ability of TAPC.Intriguingly,it is the same donor-acceptor combination which achieved the highest device efficiency when adopted as the host for red PHOLEDs.Maximum efficiencies as high as31.36 cd A^(-1),17.95 lm W^(-1),and 21.01%for the current efficiency,power efficiency and external quantum efficiency,respectively with low efficiency roll-off were realized.The improved performance can be attributed to the efficient TADF properties of the interface exciplex-forming host constituting TAPC,benefiting the F?rster energy transfer.The article first underlines the importance of the constituting molecules in the interface exciplex-forming hosts,shedding new insight about the choice of interface exciplex as the host for PHOLEDs,which may lead to even higher performances,paving their ways towards practical applications.A novel acceptor material,9-（4′-（4,6-diphenyl-1,3,5-triazin-2-yl）-[1,1′-biphenyl]-3-yl）-9H-carbazole（o-DTPPC）was developed to form interface exciplex with commonly used donors,to maximize the performances of red phosphorescent organic light emitting diodes（PHOLEDs）.It is found that the exciplex involving 4,4′-（cyclohexane-1,1-diyl）bis（N,N-di-p-tolylaniline）（TAPC）exhibits the most significant thermally activated delayed fluorescence（TADF）property,derived from the high triplet energy level as well as strong hole-transporting ability of TAPC.Intriguingly,it is the same donor-acceptor combination which achieved the highest device efficiency when adopted as the host for red PHOLEDs.Maximum efficiencies as high as31.36 cd A（-1）,17.95 lm W（-1）,and 21.01%for the current efficiency,power efficiency and external quantum efficiency,respectively with low efficiency roll-off were realized.The improved performance can be attributed to the efficient TADF properties of the interface exciplex-forming host constituting TAPC,benefiting the F？rster energy transfer.The article first underlines the importance of the constituting molecules in the interface exciplex-forming hosts,shedding new insight about the choice of interface exciplex as the host for PHOLEDs,which may lead to even higher performances,paving their ways towards practical applications.

关 键 词：thermally activated delayed fluorescence interface exciplex electron donors red phosphorescent 

分 类 号：O621.22[理学—有机化学]