Crafting host materials for narrowband blue OLEDs with low efficiency roll-off by the medium-ring strategy  

作　　者：Yuanyuan Bao Anping Luo Jingbo Lan Junjie Liu Zhengyang Bin Jingsong You 

机构地区：[1]Key Laboratory of Green Chemistry and Technology of Ministry of Education,College of Chemistry,Sichuan University,Chengdu 610064,China

出　　处：《Science China Chemistry》2024年第10期3265-3270,共6页中国科学（化学英文版）

基　　金：supported by the National Natural Science Foundation of China(22031007,22275127)。

摘　　要：The pursuit of high-performance narrowband blue organic light-emitting diodes(OLEDs)is of paramount importance in both academic research and industrial applications.While obvious strides have been made in the design of narrowband blue emitters,the development of appropriate host materials has evidently trailed behind.Herein,we introduce a medium-ring strategy for crafting host molecules based on the heptagonal tribenzo[b,d,f]azepine(TBA)unit.The twisted three-dimensional(3D)architecture of the TBA framework not only endows the host molecules with fast hole-transporting pathways but also effectively reduces exciton quenching.Equipped with two TBA units,DTBA,synthesized with ease,demonstrates a huge horizontal orientation factor(Θ//)of 93.5%and a broad emission spectrum for accelerating the energy transfer process in the emitting layer,which contributes to enhancing device performance.We have fabricated high-performance narrowband blue OLEDs using DTBA as the host,FIrpic as the phosphor sensitizer,and the widely used boron-nitrogen-containing multiple resonance emitter BCz-BN.These devices exhibit a maximum external quantum efficiency(EQEmax)as high as 31.0%with an impressively lowefficiency roll-off.Even at a high luminance level of 10,000 cd m^(-2),the EQE value remains noteworthy at 20.3%,marking a significant advancement in BCz-BN-based devices.

关 键 词：host molecule blue organic light-emitting diode low-efficiency roll-off multiple resonance C–H activation 

分 类 号：TB34[一般工业技术—材料科学与工程] TN383.1[电子电信—物理电子学]