High-efficiency and Stable Short-delayed Fluorescence Emitters with Hybrid Long- and Short-range Charge-transfer Excitations

Overview

Journal Nat Commun

Specialty Biology

Date 2023 Apr 26

PMID 37100785

Authors

Guoyun Meng

Hengyi Dai

Qi Wang

Jianping Zhou

Tianjiao Fan

Xuan Zeng

Xiang Wang

Yuewei Zhang

Dezhi Yang

Dongge Ma

Dongdong Zhang

Lian Duan

Affiliations

Soon will be listed here.

Abstract

The pursuit of ideal short-delayed thermally activated delayed fluorescence (TADF) emitters is hampered by the mutual exclusion of a small singlet-triplet energy gap (ΔE) and a large oscillator strength (f). Here, by attaching an multiresonance-acceptor onto a sterically-uncrowded donor, we report TADF emitters bearing hybrid electronic excitations with a main donor-to-acceptor long-range (LR) and an auxiliary bridge-phenyl short-range (SR) charge-transfer characters, balancing a small ΔE and a large f. Moreover, the incorporation of dual equivalent multiresonance-acceptors is found to double the f value without affecting the ΔE. A large radiative decay rate over an order of magnitude higher than the intersystem crossing (ISC) rate, and a decent reverse ISC rate of >10 s are simultaneously obtained in one emitter, leading to a short delayed-lifetime of ~0.88 μs. The corresponding organic light-emitting diode exhibits a record-high maximum external quantum efficiency of 40.4% with alleviated efficiency roll-off and extended lifetime.

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