Chiral Hybrid Copper(I) Halides for High Efficiency Second Harmonic Generation with a Broadband Transparency Window

Abstract Chiral hybrid organic–inorganic metal halides (HOMHs) with intrinsic noncentrosymmetry have shown great promise for applications in second‐order nonlinear optics (NLO). However, established chiral HOMHs often suffer from their relatively small band gaps, which lead to negative impacts on transparent window and laser‐induced damage thresholds (LDT). Here, we have synthesized two chiral HOMHs based on Cu I halides, namely ( R ‐ /S ‐MBA)CuBr 2 , which feature well‐balanced NLO performances with a highly efficient SHG response, outstanding optical transparency, and high LDT. The effective second‐order NLO coefficient of ( R ‐MBA)CuBr 2 has been determined to be ≈24.7 pm V −1 , which is two orders of magnitude higher than that of their Cu II counterparts. This work shows the promising potential of Cu I ‐based chiral HOMHs for nonlinear photonic applications in wide wavelength regions.