Tailoring ultralong organic room temperature phosphorescence through the combination strategy using small-molecule matrix and polymer matrix

Abstract

We report a combination strategy using small-molecule matrix and polymer matrix to tailor ultralong organic room temperature phosphorescence (UORTP). 5H-BTCz can be regarded as an excellent phosphorescence unit due to its characteristics of “large size + hetero atom + high rigidity”. When doped into small-molecule matrix, such as DBT and DMAP, 5H-BTCz displays observable green/yellowish-green UORTP with controllable intensity and lifetime as charge separation and charge recombination occur between 5H-BTCz and matrix molecules. In particular, the structural similarity between 5H-BTCz and DBT and the formation of strong π–π interactions significantly facilitate charge transfer between host and guest, leading to higher phosphorescence intensity but shorter phosphorescence lifetime of 5H-BTCz@DBT. Moreover, when 5H-BTCz is copolymerized into an MA/PETA crosslinked network, a self-standing UORTP film could be obtained owing to the moldability and oxygen isolation capacity of the polymer films. Furthermore, we couple the small-molecule matrix with the polymer matrix, and the advantages of both are realized in the newly doped UORTP system. The phosphorescence lifetime can be tuned in a wide range, and the phosphorescence quantum yield can be maximized to 22.18%. We believe that this work can provide a new strategy to efficiently regulate UORTP and lay the foundation for intelligent organic phosphorescence materials.