Intramolecular Through‐Space Charge Transfer Based TADF‐Active Multifunctional Emitters for High Efficiency Solution‐Processed OLED

Abstract

Abstract Thermally activated delayed fluorescence (TADF) has been explored actively in luminescent organic materials. Yet, realizing such TADF‐active, multifunctional emitters with high emission efficiency still remains hugely challenging. In this context, a series of twist‐conjugated organic molecules bearing diphenylsulfone and 9,9‐dimethylacridine moieties are designed and prepared, and are found to show, in one molecule, TADF, room‐temperature phosphorescence, triboluminescence, and aggregation‐induced emission enhancement. In addition, remarkably high photoluminescence quantum efficiency, up to ≈100%, is achieved for these novel molecules. Single‐crystal analysis and theoretical calculations reveal that the through‐space charge transfer (TSCT) effect in these molecules is responsible for both the multifunctional emission and high emission efficiency. A maximum external quantum efficiency of 20.1% is achieved, which is among the highest recorded in a solution‐processable device containing TSCT‐based TADF materials. These results illustrate a new approach to achieving highly efficient TADF‐active, multifunctional emitters.