Dual Promotion of Phosphorus Groups for Ultralong Room Temperature Phosphorescence with High Efficiency

Abstract Organic room temperature phosphorescence (RTP) materials have drawn wide attention due to their dynamic phosphorescence performance under ambient conditions. However, most of the pure organic RTP materials show low phosphorescence efficiency and short lifetime because of their weak spin–orbit coupling and fast nonradiative decay process. Introducing halogen heavy atoms can effectively improve the efficiency, while the lifetime would be shortened obviously. Thus, there is still a great challenge especially for developing halogen heavy atom free organic RTP materials, with simultaneously enhanced phosphorescence efficiency and lifetime. Herein, it is demonstrated that triphenylphosphine group possesses a strong n‐electron donating character and adopts a rigid tetrahedral configuration, which are in favor of accelerating intersystem crossing process and suppressing the nonradiative decay process, respectively. Benefited from the dual promotion of triphenylphosphine group, the obtained compound named CzPhP shows a decent phosphorescence efficiency of 14.36% and a prolonged lifetime of 340 ms. Another three pentavalent phosphine‐bearing analogs synthesized, i.e., CzPhPO, CzPhPS, and CzPhPSe, also present different conformational aggregations and good RTP performance. The diversity of the RTP performance of these compounds affords a potential application in anticounterfeiting and data encryption.