Zero-dimensional organic–inorganic hybrid indium halide perovskite with broadband yellow light emission†

Lead halide perovskites have multiple optoelectronic functions because of their intriguing photophysical properties. Unfortunately, their extensive application prospects are limited by their high toxicity and instability. For these reasons, it is significant to assemble novel lead-free halides with high-performance luminescence properties. Environment-friendly In³⁺-based halides are gaining increasing interest because of their high stabilities and photoluminescence quantum yields (PLQYs). In this research work, we synthesized a zero-dimensional (0D) hybrid indium chloride single crystal of [1-Me-Pipz]₂[InCl₆]Cl·H₂O (1-Me-Pipz = protonated 1-methylpiperazine) that demonstrated strong self-trapped exciton (STE)-associated broadband yellow light emission with a sufficient PLQY of 51.58%. Moreover, [1-Me-Pipz]₂[InCl₆]Cl·H₂O exhibits extremely excellent structural and spectral stability in a variety of harsh environments. Importantly, the outstanding optoelectronic characteristics allow indium perovskite to be used for the successful fabrication of white light-emitting diodes (WLEDs) with a high color rendering index of 86.4. This work enriches the literature on indium halide perovskites and provides a novel viewpoint for the possible applications of 0D In³⁺ perovskite-based luminescent materials.