Trifluoromethyl enable high-performance single-emitter white organic light-emitting devices based on quinazoline acceptor  

作　　者：Xiangan Song Shaogang Shen Mengyao Lu Ying Wang Yong Zhang 

机构地区：[1]School of Materials Science and Engineering,Harbin Institute of Technology,Harbin 150001,China [2]Key Laboratory of Photochemical Conversion and Optoelectronic Materials,and TIPC-CityU Joint Laboratory of Functional Materials and Device,Chinese Academy of Sciences,Technical Institute of Physics and Chemistry,Beijing 100190,China [3]University of Chinese Academy of Sciences,Beijing 100049,China

出　　处：《Chinese Chemical Letters》2024年第4期442-446,共5页中国化学快报（英文版）

基　　金：the supports by the National Natural Science Foundation of China (No.22175049);the Opening Project of Key Laboratory of Optoelectronic Chemical Materials and Devices of Ministry of Education,Jianghan University (No.JDGD-202213);the support of the Fundamental Research Funds for the Central Universities (Harbin Institute of Technology)。

摘　　要：Single-emitter white organic light-emitting diode(WOLED) based on small organic molecule exhibits great potential in simplifying fabrication process of WOLEDs. However, the design and synthesis of molecule for highly efficient single-emitter WOLED still remains a challenge. Herein, two asymmetric donor-acceptor-acceptor'(D-A-A') type molecule(PTZ-PQ-F and PTZ-PQ-CF3) are developed by employing trifluoromethyl(CF_(3)) or fluorine atom as secondary acceptor, which can exhibit white lighting with dual emission bands consisting of blue traditional fluorescence from quasi-axial(ax) conformer and orange thermally activated delayed fluorescence(TADF) from quasi-equatorial(eq) conformer. The introduction of CF_(3) into PTZ-PQ-CF3 greatly enhanced the photoluminescence quantum yield(PLQY) by suppressing the nonradiative deactivation. Owing to electron-inductive-effect of CF3, the “eq” conformer of PTZ-PQCF3 exhibits a much smaller ΔESTof 0.01 e V to realize more efficient reverse intersystem crossing(RISC)process, and then enhance the exciton utilization(nearly 100%) of the whole dual emission system. Consequently, single-emitter WOLEDs based on PTZ-PQ-CF3 show nearly standard white emission with EQE of 13.0% and CIE of(0.35, 0.36) in m CP host and show warm white emission with high EQE of 25.5%and CIE of(0.40, 0.47) in 35 Dcz PPy host, which are the best performance among reported single-emitter WOLEDs.

关 键 词：Single-emitter white organic light-emitting diode Conformational isomerism Thermally activated delayed fluorescence TRIFLUOROMETHYL Exciton utilization 

分 类 号：O626[理学—有机化学] TN383.1[理学—化学]