Unusual phosphorescence of boric acid: From impurity or clusterization-triggered emission?

Abstract

The unusual room-temperature phosphorescence (RTP) from the n electron-rich systems (without regular conjugated structure) has aroused great attention for structural designing and application development of RTP materials. Such emission has been ascribed to clusterization-triggered emission (CTE) via weak through-space conjugation of n electrons in the heteroatoms. However, there was suspicion on such RTP as impurity-induced result. Therefore, in-depth photophysical investigation and effective proof methods are needed to trace the origin of such RTP. Here, using the recently reported CTE phosphor boric acid as the example, a Jablonski diagram-based verification protocol was proposed to confirm the intrinsic luminescence of the n electrons-rich systems. Meanwhile, some other types of luminophores, that is, traditional phosphors, already reported impurity-induced and host-guest doping luminophores, were included for comparison. Overall, this work provides a basic paradigm for differentiating between the impurity-involved and the n electron-rich phosphors and will further deepen the understanding of nonconventional luminescence.

Keywords

boric acid / clusterization-triggered emission / impurity-induced phosphorescence / through-space conjugation

RIGHTS & PERMISSIONS

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