Room-Temperature Liquid Crystalline Unsymmetrical S-Annulated Perylene Diester Imide as a Dopant for Greenish-Yellow OLEDs with high EQE of 6.9 %

Abstract

The quest for highly luminescent, cost-effective, and metal-free materials is driving innovation in organic light-emitting diode (OLED) technology. Herein, we unveil a novel unsymmetrical bay S-incorporated perylene diester imide (PEI-SST), stabilizing room temperature columnar hexagonal phase over a wide thermal range, that was prepared by microwave assisted synthesis. PEI-SST demonstrates a remarkable photoluminescence quantum yield of 83 %. As a dopant in a CBP based host-guest OLED, at 1.0 wt.%, PEI-SST delivered a promising greenish-yellow electroluminescence with an exceptional EQEmax of 6.9% and a brightness of 2,529 cd/m².