Circularly Polarized Luminescence from Zero‐Dimensional Hybrid Lead‐Tin Bromide with Near‐Unity Photoluminescence Quantum Yield

Zero-dimensional (0D) hybrid metal halides with perfect host-guest structures are promising candidates to construct circularly polarized luminescence (CPL)-active materials. However, it still remains challenging to obtain 0D chiral metal halides with simultaneously strong CPL and high photoluminescence quantum yield. Here, a new enantiomeric pair of 0D hybrid lead-tin bromides, (RR/SS-C N H ) Pb Sn Br  ⋅ 2H O (R/S-PbSnBr ⋅ H O), is reported. The R/S-PbSnBr ⋅ H O compounds not only show intriguing self-trapped exciton emissions with near-unity quantum yield, but also present intense CPL with a dissymmetry factor g of ±3.0×10 . Such CPL activities originate from the asymmetric [SnBr ] luminophores in R/S-PbSnBr ⋅ H O, due to the induced structural chirality by the organic ligands via N-H⋅⋅⋅Br hydrogen bonds. Furthermore, CPL emissions with tunable colors from R/S-PbSnBr ⋅ H O and dehydrated compounds are reversibly observed, which extends their chiroptical applications.