Identifying the Exciplex-to-Exciplex Energy Transfer in Tricomponent Exciplex-Based OLEDs through Magnetic Field Effect Measurements

• DOI: 10.1021/acsphotonics.2c00469
• Publication Date: 2022-07-29T15:41:35Z
• Authors: Fengjiao Wu; Xi Zhao; Hongqiang Zhu; Xiantong Tang; Yaru Ning; Jing Chen; Xiaoli Chen; Zuhong Xiong
• Keywords: Excimer; Intersystem crossing; Quantum Efficiency; Acceptor

Tricomponent exciplex-based organic light-emitting diodes (TE-OLEDs) with high- and low-energy exciplexes have recently gained much attentions because of their already-reported high external quantum efficiency (EQE) exciplex-to-exciplex energy transfer (EE-ET) is considered as an important factor to influence the device performance. However, few works provide evidence prove this EE-ET process due lack absorption band exciplexes. Herein, channel from a high-energy exciplex donor (EXED) another acceptor (EXEA) in TE-OLED demonstrated by probing magnetic field effects (MFEs) on electrical optical properties devices including magneto-conductance (MC), magneto-efficiency (Mη), magneto-electroluminescence (MEL), can evolution channels spin-pair states which could be visualized these featured MFE traces. Specifically, all MC, Mη, MEL curves single EXED-based OLED depict normal bias-current (I)-dependent intersystem crossing (ISC) singlet triplet polaron pairs, weakens increasing I. Moreover, Mη traces EXEA-based OLED, respectively, present abnormal I-dependent ISC, while its MC show conversion reverse ISC (RISC) pairs both simultaneous EXED EXEA RISC exciplexes, enhances I, display RISC. These behaviors seldom been observed previously literature, are induced that facilitate via quantity states. higher EQE obtained than OLED. Thus, measurements new strategies for recognizing OLEDs based multiple emitter systems pave way designing superior performance OLEDs.