A new insight into aggregation structure of organic solids and its relationship to room-temperature phosphorescence effect

Abstract

In order to improve the performance of organic luminescent materials, lots of studies have been carried out at the molecular level. However, these materials are mostly applied as solids or aggregates in practical applications, in which the relationship between aggregation structure and luminescent property should be paid more attention. Here, we obtained five phenothiazine 5,5-dioxide (O-PTZ) derivatives with distinct molecular conformations by rational design of chemical structures, and systematically studied their room-temperature phosphorescence (RTP) effect in solid state. It was found that O-PTZ dimers with quasi-equatorial (eq) conformation tended to show stronger π-π interaction than quasi-axial (ax) conformers in crystal state, which was more conducive to the generation of RTP. Based on this result, a multi-level structural model of organic solids was proposed to draw the relationship between aggregation structure and RTP effect, just like the research for the structureproperty relationship of proteins. Using this structural model as the guide, boosted RTP efficiency from 1% to 20% was successfully achieved in the corresponding host-guest doping system, showing its wide applicability.

Keywords

molecular conformation / multi-level structural model / room-temperature phosphorescence / phenothiazine 5,5-dioxide derivatives / aggregation

RIGHTS & PERMISSIONS

2023 2023 The Authors. Aggregate published by South China University of Technology; AIE Institute and John Wiley & Sons Australia, Ltd.