Efficient red-emitting tin hybrid halides exhibiting large Stokes shift and high PLQY for lighting and anti-counterfeiting applications

The development of efficient red-emitting tin hybrid halides that display a large Stokes shift and zero self-absorption is highly desirable because of their tremendous potential in solid-state lighting and anticounterfeiting applications. However, such materials are difficult to obtain and have rarely been reported. Herein, we present a layered tin halide hybrid, (C₄H₁₂N₂)₂[SnCl₆], in which crystallographically independent [SnCl₆] octahedra alternate with organic bilayers. Remarkably, (C₄H₁₂N₂)₂[SnCl₆] shows bright red emission with a large Stokes shift of 3.04 eV and a high photoluminescence quantum yield (PLQY) of 70%. Structural analyses reveal that the large Stokes shift and high PLQY stem from the compact lattice, shortened Sn⋯Sn separations, and low dimensionality, which together enhance radiative recombination while permitting greater structural relaxation in the excited state. Consequently, (C₄H₁₂N₂)₂[SnCl₆] is an excellent red phosphor with promising prospects for application in white light-emitting diodes and anti-counterfeiting technologies. In short, this study elucidates the structure-property-application relationships of tin hybrid halides, paving the way toward high-performance emissive metal-halide materials.