Constructing an efficient deep-blue TADF emitter by host-guest interactions towards solution-processed OLEDs with narrowband emission  

作　　者：Yanchao Xie Lei Hua Zhi Wang Yuerong Liu Shian Ying Yuchao Liu Zhongjie Ren Shouke Yan 

机构地区：[1]Department Key Laboratory of Rubber-Plastics,Ministry of Education/Shandong Provincial Key Laboratory of Rubber-Plastics,School of Polymer Science and Engineering,Qingdao University of Science&Technology,Qingdao 266042,China [2]State Key Laboratory of Chemical Resource Engineering,College of Materials Science and Engineering,Beijing University of Chemical Technology,Beijing 100029,China

出　　处：《Science China Chemistry》2023年第3期826-836,共11页中国科学（化学英文版）

基　　金：supported by the National Natural Science Foundation of China(52103220,51922021,52273164);the Shandong Provincial Natural Science Foundation(ZR2022ZD37,ZR2019ZD50).

摘　　要：High-efficiency thermally activated delayed fluorescence(TADF) emitters and corresponding well-designed solution-processed organic light emitting diodes(OLEDs) are presently attractive due to their potential for exploiting large-area flexible displays. In this context, we innovatively integrate 2,12-di-tert-butyl-5,9-dioxa-13b-boronaphtho [3,2,1] anthracene as the acceptor with 3,6-bis(3,6-di-tert-butylcarbazol-N-yl) carbazole as the donor to construct a rigid deep-blue emitter, TB-3t BuCz, which exhibits a narrow emission with full-width-at-half-maximum(FWHM) of 46 nm. TB-3t BuCz itself dispalys no TADF characteristics both in solution or in pure film states. However, the significant TADF behavior can be observed when TB-3t BuCz is doped with 2,6-DCzPPy host due to the formation of exciplex-like species in 2,6-DCzPPy/TB-3t BuCz system. It is also found that the discernible spin-flip of triplet excitons is feasible when the S1/T1states of the formed exciplex stay slightly lower than S1 and T1states of TB-3t BuCz for the other host/TB-3t BuCz systems. Eventually, thanks to the synergetic effect of rigid structure and favorable photophysical properties of TB-3t BuCz, the solution-processed OLEDs based on 2,6-DCzPPy/TB-3t BuCz as emitting layer has achieved the significantly improved external quantum efficiency(EQE) of 14.6% with suppressed efficiency roll-off.The CIE1931 coordinate of(0.158, 0.052) is typically in deep-blue region. Note that, this EQE value is among the highest echelon of solution-processed OLEDs with deep-blue emission by utilizing boron-containing TADF emitters.

关 键 词：thermally activated delayed fluorescence oxygen-bridged cyclized boron host-guest interactions solution-processed OLEDs narrowband deep-blue emission 

分 类 号：O641.3[理学—物理化学]