Thermally Activated Delayed Fluorescence Polysiloxanes with Short Delay Fluorescence Lifetimes

Blue‐emitting thermally activated delayed fluorescence (TADF) polymers are still in demand for high‐efficiency display materials. Through‐space charge transfer (TSCT) strategy is promising for keeping color purity of blue‐emitting polymers with nonconjugated main chains. It is, however, hard to synthesize copolymers with well‐dispersed donors or acceptors utilizing traditional polyethylene backbones via radical polymerization. Herein, two series of blue‐emitting polysiloxane with TADF properties, random and order‐controlled copolysiloxanes, are successfully designed and synthesized and their photophysical properties are investigated and compared in detail. All of them display short prompt and delay fluorescence lifetimes and a very fast reverse intersystem crossing (RISC) rate of 107 s−1. Compared with random copolysiloxanes, acceptors are well separated by donors for order‐controlled copolysiloxanes, which exhibit the faster RISC processes and the higher photoluminescence quantum yield. Therefore, the order‐controlled architecture provides a guide for improving light‐emitting efficiency of TSCT‐type TADF polymers. Two series of blue‐emitting polysiloxanes with through space charge transfer type thermally activated delayed fluorescence are prepared. Controlled polymerization ensures the acceptors being spaced apart by donors. Compared with random copolysiloxanes, order‐controlled ones display a faster reverse intersystem crossing rate and a higher photoluminescence quantum efficiency.