Unsymmetrical S-annulated perylene diester imide, stabilizing room temperature columnar phase as a dopant for greenish-yellow OLEDs with an outstanding 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-S^ST), stabilizing a room temperature columnar hexagonal phase over a wide thermal range, that was prepared by microwave-assisted synthesis. PEI-S^ST demonstrates a remarkable photoluminescence quantum yield of 83%. As a dopant in a CBP-based host–guest OLED, at 1.0 wt%, PEI-S^ST delivered a promising greenish-yellow electroluminescence with an exceptional EQE_max of 6.9% and a brightness of 2529 cd m⁻².