1D Tin(II)‐Based Chiral Hybrid Perovskite Single Crystals with Extremely Distorted Inorganic Chains for Second Harmonic Generation

Abstract The organic–inorganic hybrid metal halides with chiral structures have attracted great attentions in the field of optoelectronic functional materials, especially for nonlinear optics. To date, second harmonic generation (SHG) properties of several classes of chiral hybrid halides with different metal ions have been reported. However, SHG‐active tin(II)‐based chiral materials are rarely explored, hindering deep understandings of the relationship between their structures and SHG properties. Herein, Sn 2+ ions are successfully introduced into chiral hybrid perovskites, and four new species of chiral hybrid perovskites ( R / S ‐α‐PEA)SnX 3 (X = Cl and Br, PEA = phenylethylammonium) are obtained. The as‐grown crystals are in P 2 1 2 1 2 1 space group, with highly distorted [SnX 6 ] octahedral units forming 1D chain structures in the lattice, due to the effect of stereochemically active lone pair 5s 2 electrons in Sn 2+ . Such crystals have an SHG response of ≈1.4× Y‐cut α‐quartz for ( S ‐α‐PEA)SnBr 3 and ≈0.9× Y‐cut α‐quartz for ( S ‐α‐PEA)SnCl 3 at 1020 nm excitation, with high polarization ratio of SHG signals as well as wide bandgaps and transparency windows in the meanwhile. This work opens up a new platform for discovering more novel tin(II)‐based chiral perovskites with superior nonlinear optical properties in the future.