Tailoring Ultralong Organic Room Temperature Phosphorescence through the Combination Strategy of Small-molecule Matrix and Polymer Matrix

Abstract

We report a combination strategy of 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 occurs between 5H-BTCz and matrix molecules. In particular, structural similarity between 5H-BTCz and DBT and formation of strong π-π interactions significantly facilitates charge transfer between host and guest, leading to higher phosphorescence intensity but shorter phosphorescence lifetime of 5H-BTCz@DBT. Moreover, when 5H-BTCz was copolymerized into the MA/PETA crosslinked network, a self-standing UORTP film can be obtained owing to moldability and oxygen isolation capacity of polymer films. Furthermore, we couple the small-molecule matrix with the polymer matrix and advantages of both strategies can be realized in the new doping UORTP system. The phosphorescence lifetime can be tuned in a wide range and the phosphorescence quantum yield can maximize to 22.18%. We believe that this work can give a new strategy to efficiently regulate UORTP and lay foundation for intelligent organic phosphorescence materials.