Stable zero-dimensional hybrid indium-based halides with yellow to orange light emission

Low-dimensional organic-inorganic hybrid materials (OIHMs) in the field of luminescence have been occupying promising application prospects, but the toxicity and instability of lead-based halides are huge obstacles to the industrial utilization of these materials. Developing lead-free halides with low-toxicity and high stability have become important topics of research in recent years. Herein, we report three 0D In-based OIHMs (ABI)₃(InBr₆)Br (ABI = 2-aminium benzo-imidazole) 1, (DMA)₄(InBr₆)Br (DMA = dimethylammonium) 2, and (BAPP)(InBr₆)Br·6H₂O (BAPP = 1,4-bis(3-aminopropyl)piperazine) 3, which show maximum emission peaks within 605-622 nm, with a photoluminescence quantum yield (PLQY) of 60.80% being the highest achieved. More significantly, after one week of immersion in various organic solvents, these halides exhibit no structural degradation with their luminous intensity being well maintained. In addition, halide 1 as a yellow phosphor is used in the preparation of white light-emitting diodes (LEDs) with a high colour rendering index (CRI) of 90.3. This work provides new ideas and strategies for lead-free-based OIHMs in the field of optoelectronic materials.