Achieving Near-Unity Red Light Photoluminescence in Antimony Halide Crystals via Polyhedron Regulation.

Exploration of efficient red emitting antimony hybrid halide with large Stokes shift and zero self-absorption is highly desirable due to its enormous potential for applications in solid light emitting, and active optical waveguides. However, it is still challenging and rarely reported. Herein, a series of (TMS) 2 SbCl 5 (TMS=triphenylsulfonium cation) crystals have been prepared with diverse [SbCl 5 ] 2- configurations and distinctive emission color. Among them, cubic-phase (TMS) 2 SbCl 5 shows bright red emission with a large Stokes shift of 312 nm. In contrast, monoclinic and orthorhombic (TMS) 2 SbCl 5 crystals deliver efficient yellow and orange emission, respectively. Comprehensive structural investigations reveal that larger Stokes shift and longer-wavelength emission of cubic (TMS) 2 SbCl 5 can be attributed to the larger lattice volume and longer Sb⋅⋅⋅Sb distance, which favor sufficient structural aberration freedom at excited states. Together with robust stability, (TMS) 2 SbCl 5 crystal family has been applied as optical waveguide with ultralow loss coefficient of 3.67 ⋅ 10 -4  dB μm -1 , and shows superior performance in white-light emission and anti-counterfeiting. In short, our study provides a novel and fundamental perspective to structure-property-application relationship of antimony hybrid halides, which will contribute to future rational design of high-performance emissive metal halides.