Harnessing the Dual Role of DMSO in the Synthesis of SbOCl·DMSO: An Excellent UV Nonlinear Optical Crystal with Unique 1D Spiral Chain

Ultraviolet (UV) nonlinear optical (NLO) materials are essential for applications such as laser micromachining and optical parametric oscillations. An ideal UV NLO material should exhibit a large second-harmonic generation (SHG) coefficient, moderate birefringence and a short UV cut-off edge. However, achieving these properties simultaneously in a single material remains a significant challenge due to their distinct structural requirements. In this study, we report the synthesis of a novel UV NLO material, SbOCl·DMSO, which features an optimized 1D helical chain structure. For the first time, the polar organic molecule dimethyl sulfoxide (DMSO) is introduced into the SbCl₃ system, where it coordinates with Sb atom via Sb-O bonds, modifying the chain structure. This unique 1D [SbOCl]_∞ helical chain enhances the compound’s polarizability and optical anisotropy, leading to excellent optical properties. SbOCl·DMSO exhibits a large SHG coefficient of 4.4 × KDP, moderate birefringence of 0.084@546 nm and a short UV cut-off edge of 331 nm, making it a highly promising candidate for UV NLO applications. This work highlights the importance of synergistic molecular design and provides a new strategy for the development of high-performance frequency-doubling crystals.