Abstract
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(CF3)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 CF3 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-PQ-CF3 exhibits a much smaller ΔEST of 0.01 eV to realize more efficient reverse intersystem crossing(RISC)process,and then enhance the exciton utilization(nearly 100％)of the whole dual emission system.Con-sequently,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 mCP host and show warm white emission with high EQE of 25.5％and CIE of(0.40,0.47)in 35 DczPPy host,which are the best performance among reported single-emitter WOLEDs.
基金项目
国家自然科学基金(22175049)
Open-ing Project of Key Laboratory of Optoelectronic Chemical Materi-als and Devices of Ministry of Education,Jianghan Unive(JDGD-202213)
Fundamental Re-search Funds for the Central Universities(Harbin Institute of Tech-nology)()
NETL
NSTL
万方数据