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

• 来源期刊: 中国科学:化学（英文版）
• 年，卷（期）: 2018,（7）
• 页码范围: 836-843
• 页数: 8页
• 语种: 英文

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-l,l-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 as 31.36 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-offwere realized.The improved performance can be attributed to the efficient TADF properties of the interface exciplex-forming host constituting TAPC,benefiting the F(o)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.