The Role of Locally Excited State and Charge Transfer State in Organic Room Temperature Phosphorescence and Corresponding Applications

Abstract

Donor–acceptor (D–A) structure with charge transfer (CT) effect is widely utilized in the construction of organic luminescent materials. The adjustment of their CT effect and related luminescent property usually relies on the changes of molecular structure with different D or A moieties, which will lead to some uncertainties in structure‐property relationship. With the aim to explore the clear inherent luminescent mechanism for D–A molecule with CT effect, it is ideal that the regulation of intramolecular charge transfer in one same D–A molecule can be realized. Accordingly, three D–A type organic phosphorescence luminogens are designed and synthesized. Once being doped into different polymer matrixes, disparate charge transfer effects and related room temperature phosphorescence (RTP) properties can be achieved for a single molecule. Subsequent experiments confirm that different distributions of molecules with locally excited (LE) state and CT state are mainly responsible for their distinct RTP behaviors, exhibiting the well‐clarified structure‐property relationship of D–A type phosphorescence luminogens. Furthermore, the transition from CT to LE state can even be realized through chemical reaction, leading to the activated RTP effect for practical applications.