Direct Room Temperature Synthesis of α-CsPbI₃ Perovskite Nanocrystals with High Photoluminescence Quantum Yields: Implications for Lighting and Photovoltaic Applications

Cesium-lead iodide perovskite nanocrystal (PNC) is a promising material for efficient solar cells and red-light-emitting diodes, especially for the cubic-structured α polymorph with its ideal band-gap energy. We report the first room temperature, one-pot synthesis of α-CsPbI₃PNCs in open air, achieved by optimized ligand-solvent combinations to control the crystallization kinetics and phase preference of CsPbI₃. The resulting 6.0-nm-sized, α-phase nanocubes have photoluminescence peaks at 642 nm (full-width at half-maximum: 44 nm) and absolute quantum yields of up to 83% after purification. The method is simple, reproducible, scalable, and generalizable to other cesium-lead halide and formamidinium lead iodide PNCs.