Optimization of Exciton Recombination toward High-Efficient Emission in Tin/Yttrium-Based Hybrid Perovskite

The exceptional photoluminescence (PL) efficiency of tin-based perovskites has garnered significant scientific interest. However, the high performance of these materials is predominantly dependent on antimony (Sb) doping, raising concerns regarding Sb toxicity. To address this critical issue, we propose an innovative approach by introducing low-toxicity Y3+ as a dopant and synthesizing a novel perovskite single crystal through advanced crystal growth techniques. By implementing strategic structural modifications, we achieve a substantial improvement in the luminescence performance of the perovskite single crystal. These structural alterations demonstrate an intensified electron–phonon coupling and enhanced electron localization, thereby optimizing the formation efficiency of self-trapped excitons. The resultant (4PPY·H)2Sn0.864Y0.136Cl5.864 single crystal exhibits remarkable photoluminescence properties, achieving a quantum yield of up to 96%. Furthermore, the fluorescence lifetime of the doped crystal demonstrates a more than 2-fold increase compared to its undoped counterpart.