Highly efficient hybrid warm white organic light-emitting diodes using a blue thermally activated delayed fluorescence emitter: exploiting the external heavy-atom effect  

作　　者：Dongdong Zhang Lian Duan Yunge Zhang Minghan Cai Deqiang Zhang Yong Qiu 

机构地区：[1]Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education,Department of Chemistry,Tsinghua University,Beijing 100084,China

出　　处：《Light(Science & Applications)》2015年第1期562-568,共7页光（科学与应用)（英文版）

基　　金：We would like to thank the National Natural Science Foundation of China(Grant Nos.51173096,21161160447 and 61177023)for financial support.

摘　　要：To attain high efficiencies in hybrid white organic light-emitting diodes(WOLEDs),mutual quenching of the fluorophors and phosphors should be minimized.Efforts have been devoted to reducing the triplet quenching of phosphors;however,the quenching of fluorophors by the external heavy-atom effect(EHA)introduced by the phosphors is often ignored.Here,we observed that conventional fluorophors and fluorophors with thermally activated delayed fluorescence(TADF)behave differently in the presence of EHA perturbers.The efficiencies of the conventional fluorophors suffer greatly from the EHA,whereas the TADF fluorophors exhibit negligible changes,which makes TADF materials ideal fluorophors for hybrid devices.WOLEDs using a blue TADF fluorophor and an orange phosphor achieve a maximum forward viewing external quantum efficiency of 19.6%and a maximum forward viewing power efficiency of 50.2 lm W^(-1),among the best values for hybrid WOLEDs.This report is the first time that the EHA effect has been considered in hybrid WOLEDs and that a general strategy toward highly efficient hybrid WOLEDs with simple structures is proposed.

关 键 词：external heavy-atom effect hybrid white OLEDs thermally activated delayed fluorescenceexternal heavy-atom effect hybrid white OLEDs thermally activated delayed fluorescence 

分 类 号：TN3[电子电信—物理电子学]