An Azaryl-Ketone-Based Thermally Activated Delayed Fluorophore with Aggregation-Induced Emission for Efficient Organic Light-Emitting Diodes with Slow Efficiency Roll-Offs.

Achieving the concurrent manifestation of thermally activated delayed fluorescence (TADF) and aggregation-induced emission (AIE) within a single molecular system is highly sought after for organic light-emitting diodes (OLEDs), yet remains rare. In this study, we present a novel TADF-AIE dye, named PQMO-PXZ, which has been designed, synthesized, and systematically characterized. Our comprehensive investigation, which includes structural analysis, theoretical calculations, and optical studies, evaluates the potential of PQMO-PXZ for integration into OLEDs. Unlike existing azaryl-ketone-based emitters, PQMO-PXZ exhibits red-shifted emission and enhanced luminescence efficiency, due to its rigid structure and strong intramolecular charge transfer characteristics. Significantly, PQMO-PXZ demonstrates pronounced AIE properties and TADF with a short delayed lifetime. When utilized as the emissive core, OLED devices based on PQMO-PXZ achieve a respectable external quantum efficiency of up to 11.8 % with minimal efficiency roll-off, underscoring PQMO-PXZ's promise as a highly efficient candidate for OLED applications.