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Highly Efficient Ultralong Organic Phosphorescence through Intramolecular-Space Heavy-Atom Effect
journal contributionposted on 2019-01-23, 00:00 authored by Huifang Shi, Lulu Song, Huili Ma, Chen Sun, Kaiwei Huang, Anqi Lv, Wenpeng Ye, He Wang, Suzhi Cai, Wei Yao, Yujian Zhang, Ruilin Zheng, Zhongfu An, Wei Huang
Metal-free organic phosphorescent materials have attracted considerable attention in the fields of organic electronics and bioelectronics. However, it remains a great challenge to achieve organic phosphors with high quantum efficiency in a single-component system. We designed and synthesized two organic phosphors (PDCz and PDBCz) with an ultralong organic phosphorescence (UOP) feature. Both molecules showed ultralong emission lifetime of >200 ms. For PDBCz crystal, it was found that the absolute phosphorescence quantum efficiency reaches up to 38.1%. Combining the experimental and theoretical studies, the highly efficient UOP was mainly attributed to the intramolecular space heavy-metal effect, which facilitates the spin–orbit coupling between singlet and triplet excited states to effectively promote the intersystem crossing. This study will provide a new platform to rationally design highly efficient UOP materials and show its potential in the field of flexible electronics.