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

摘要

Organic room temperature phosphorescence (RTP) materials have drawnwide attention due to their dynamic phosphorescence performance underambient conditions. However, most of the pure organic RTP materials showlow phosphorescence efficiency and short lifetime because of their weakspin–orbit coupling and fast nonradiative decay process. Introducing halogenheavy atoms can effectively improve the efficiency, while the lifetime wouldbe shortened obviously. Thus, there is still a great challenge especially fordeveloping halogen heavy atom free organic RTP materials, with simultaneouslyenhanced phosphorescence efficiency and lifetime. Herein, it isdemonstrated that triphenylphosphine group possesses a strong n-electrondonating character and adopts a rigid tetrahedral configuration, which arein favor of accelerating intersystem crossing process and suppressing thenonradiative decay process, respectively. Benefited from the dual promotionof triphenylphosphine group, the obtained compound named CzPhP showsa decent phosphorescence efficiency of 14.36% and a prolonged lifetime of340 ms. Another three pentavalent phosphine-bearing analogs synthesized,i.e., CzPhPO, CzPhPS, and CzPhPSe, also present different conformationalaggregations and good RTP performance. The diversity of the RTP performanceof these compounds affords a potential application in anticounterfeitingand data encryption.