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The design and construction of chiral phosphors with significant long-lived triplet exciton decay have received great attention because of their prospective applications in ultra-long circularly polarized roomtemperature phosphorescence (CP-RTP) for chiral optics. However, the practical utilization of pure organics as triplet incubators is often hindered by their spin-forbidden transition. Therefore, it is a substantial challenge for the developments of organic-derived CPRTP emitters with both long lifetimes and asymmetry factors. Herein, via precisely manipulating hybridized local and charge transfer (HLCT) and multiple n−π* effects, we report the first P,N-embedded tactic to construct the BINAP-derived emitters, which show tunable circularly polarized luminescence (CPL) with near-unity photoluminescence quantum efficiency (PLQY = 95.3%), |glum| values (1.2 to 6.2 × 10−3), and ultra-long RTP with remarkable lifetime as long as 448 ms in the polymethyl methacrylate. Experiments and quantum chemistry simulations unveil that the abovementioned triplet decay is derived from tunable HLCT and a balanced electric-magnetic dipole moment environment. Moreover, the synergetic enhancement of chemical and configurational stability enables stable chiral diradicals with a high diradical character (y0 = 0.953) and near-infrared ray (NIR) optical activity. This work provides important clues for CP-RTP phosphors and chiral diradical materials.
Yang et al. (Tue,) studied this question.