Dendritic Oligomers‐Based Exciplex Emitters Realizing Solution‐Processed Organic Light‐Emitting Diodes with Nearly 30% External Quantum Efficiency
Ming Zhang, Dianming Sun, K. Wang, Jing Chen, Yinqiong Zhou, Heng‐Yuan Zhang, Zhuo Hao, Zuhong Xiong, Hui Lin, Si‐Lu Tao, Caijun Zheng, Xiaohong Zhang
Abstract
Abstract Due to the feature of the strong intermolecular interactions causing aggregation‐caused excitons quenching (ACQ) of solution process, realizing high‐performance solution‐processed organic light‐emitting diodes (OLEDs) based on thermally activated delayed fluorescence (TADF) emitters remains a formidable challenge nowadays. To address this issue, herein, a novel strategy is proposed to construct solution‐processable ternary exciplex emitters by utilizing the dendritic oligomer as the substrate, simultaneously realizing excellent solution‐process adaptability, good dispersibility to restrain harmful ACQ, and improved exciton utilization with multiple reverse intersystem crossing channels. Accordingly, dendritic oligomer‐based exciplex systems are constructed by combining small‐molecule donor and acceptor components with the multi‐carbazole‐substituted tetraphenylsilane‐core analog as substrate. And their film morphologies, photoluminescence quantum yields (Φ PL s), and non‐radiative decay rates of triplet excitons ( k nr T s) are significantly improved. Among them, DMAC‐DPS:PO‐T2T:SimCP3 exhibits the highest Φ PL of 97.5% and the lowest k nr T of 1.0 × 10 3 s −1 , and realizes the best maximum external quantum efficiency of 29.7% in solution‐processed OLED, which is comparable with the highest electroluminescence efficiencies of all solution‐processable emitters. Therefore, this work will provide a prospective pathway to develop efficient solution‐processable exciplex emitters and promote the progress of solution‐processed OLEDs.