Highly efficient exciplex-emission from spiro[fluorene-9,9′-xanthene] derivatives

• Published in: Dyes and pigments 2021-02, Vol.185, p.108894, Article 108894
• Main Authors: Cao, Hong-Tao, Wan, Jun, Li, Bo, Zhang, He, Xie, Ling-Hai, Sun, Chen, Feng, Quan-You, Yu, Wen-Jing, Huang, Wei
• Format: Article
• Language: English
• Subjects: Electron acceptor; Exciplex-emission; Organic light-emitting device; Spiro[fluorene-9,9′-xanthene]; Thermally activated delayed fluorescence
• ISSN: 0143-7208; 1873-3743
• DOI: 10.1016/j.dyepig.2020.108894

Exciplex-thermally activated delayed fluorescence (TADF) is significant due to its potential in energy-saving and flexible techniques, but still suffers from complicated-synthesis materials and low-efficiency devices. Herein, we synthesize two new spiro[fluorene-9,9′-xanthene] (SFX)-based acceptors, 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-SFX (TRZSFX) and 2,7-bis(4,6-diphenyl-1,3,5-triazin-2-yl)-SFX (DTRZSFX) via convenient method, and obtain exciplex-emitters using the tris(4-carbazoyl-9-ylphenyl)amine (TCTA) as a donor. The results suggest that two devices based on TCTA:TRZSFX and TCTA:DTRZSFX display excellent exciplex-TADF accompanied by appealing efficiencies of 79.6 cd A−1 and 78.1 lm W−1. Encouragingly, a maximum value of 22.5% in external quantum efficiency (EQE) is realized for TCTA:TRZSFX-based device, which is higher than those of most reported exciplex OLEDs as far as we know. Our work offers a promising avenue for developing high-efficiency exciplex-emissions. [Display omitted] Two novel triazine-substituted spiro[fluorene-9,9′-xanthene] derivatives are prepared as electron acceptors to form high-performance exciplex-emissions with excellent efficiencies of 79.6 cd A−1, 78.1 lm W−1 and 22.5%. •Two triazine-substituted SFX derivatives were synthesized as electron acceptors.•The triazine-substituted acceptors possess exciplex-TADF feature.•The TCTA:TRZSFX film exhibits photoluminescence efficiency of 73%.•The TCTA:TRZSFX-based device displays external quantum efficiency of 22.5%.•The excellent emission efficiencies benefit from the triazine-substitution in SFX.