Organic−Inorganic Hybrid Perovskite-Like Indium Chloride with Strong Red Emission

Low-dimensional organic–inorganic hybrid metal halide materials have attracted widespread attention due to their excellent and tunable photoelectric properties. However, the low intrinsic photoluminescence quantum yields (PLQYs) limit their further applications in optoelectronic devices. Here, we report the synthesis of lead-free zero-dimensional hybrid organic–inorganic indium chloride crystals, (FA)₃InCl₆: xSb³⁺, with strong red-light emission through controlled Sb³⁺ doping. The optimal composition, (FA)₃InCl₆: 20.16% Sb³⁺, exhibits PLQY up to 30% and emits red broadband light centered at 690 nm. The photoluminescence enhancement of the doped samples was investigated by combining temperature-dependent and wavelength-dependent photoluminescence spectra, revealing the self-trapped exciton (STE) recombination process. The clear elucidation of the self-trapped exciton complexation process has provided a solid theoretical basis for the further optimization of the material properties, which is of great significance for the development of new red light-emitting materials. Far-red light-emitting phosphor-converted LED devices have been constructed with these materials and demonstrate stable and efficient red-light emission at various voltages, exhibiting superior photoluminescence stability. This study highlights the potential of Sb³⁺-doped metal halides to achieve tunable broadband emission and demonstrates the great potential of these metal halide single crystals for indoor plant lighting, infrared imaging, photodynamic therapy and wound healing.