Lead‐Free, Blue Emitting Bismuth Halide Perovskite Quantum Dots

Abstract Lead halide perovskite quantum dots (QDs) are promising candidates for future lighting applications, due to their high quantum yield, narrow full width at half maximum (FWHM), and wide color gamut. However, the toxicity of lead represents a potential obstacle to their utilization. Although tin(II) has been used to replace lead in films and QDs, the high intrinsic defect density and oxidation vulnerability typically leads to unsatisfactory material properties. Bismuth, with much lower toxicity than lead, is promising to constitute lead‐free perovskite materials because Bi3+ is isoelectronic to Pb2+ and more stable than Sn2+. Herein we report, for the first time, the synthesis and optical characterization of MA3Bi2Br9 perovskite QDs with photoluminescence quantum yield (PLQY) up to 12 %, which is much higher than Sn‐based perovskite nanocrystals. Furthermore, the photoluminescence (PL) peaks of MA3Bi2X9 QDs could be easily tuned from 360 to 540 nm through anion exchange.