Achiral Fluorinated Aromatic Ligands Based Chiral Hybrid Antimony Halides with High‐Efficiency Second‐Harmonic Generation

Abstract Hybrid organic−inorganic metal halides (HOMHs) have emerged as an ideal platform for the construction of semiconductor materials with promising optoelectronic properties. A number of HOMHs based on different metals including Sb³⁺ have been demonstrated with second‐harmonic generation (SHG) properties, but their nonlinear optical (NLO) performances including effective conversion wavelength range, optical stability, and NLO coefficients are not yet satisfactory. Here, by adopting a molecular design involving fluorine‐substitution on the achiral organic ammonium, this work has synthesized single crystals of two new chiral noncentrosymmetric HOMHs, (2‐FPEA)₂SbX₅ (X = Cl and Br), with large polarization ratios and outstanding optical transparency. The second‐order NLO coefficients of (2‐FPEA)₂SbCl₅ and (2‐FPEA)₂SbBr₅ are determined to be ≈24.3 and 21.6 pm V⁻¹. Significantly, the Sb³⁺‐based HOMHs enable very high thermal stability and laser resistance. The distinguished laser‐induced damage thresholds (LDTs) have been estimated to be as high as 3.44 mJ cm⁻² for (2‐FPEA)₂SbCl₅ and 3.32 mJ cm⁻² for (2‐FPEA)₂SbBr₅, higher than that of the reported HOMHs. Such a highly efficient SHG performance and stability indicate the promising future of these Sb³⁺‐based metal halides for nonlinear photonic applications.