Cost-Effective Strategy for the Synthesis of Air-Stable CH3NH3PbX3 (X = Cl, Br, and I) Quantum Dots with Bright Emission.

Lead halide perovskite quantum dots (QDs) are known as prospective optoelectronic device materials because of their excellent luminescence, extraordinary photoelectric performance, and specific octahedron framework. Herein, we report a cost-effective approach for synthesizing highly stable CH3NH3PbBr3 QDs in low-polarity binary solvents without nitrogen protection. The CH3NH3PbBr3 QDs are tunable from 1.2 to 4.2 nm by adjusting the proportion of oleic acid and oleylamine as capping ligands. The photoluminescence quantum yield of CH3NH3PbBr3 QDs can reach 87.4%. The fluorescence can maintain over 80% of its earliest emission intensity under the atmosphere after 5 days, which is much better than that (∼10%) of QDs with ligand-assisted reprecipitation. The possible reaction mechanism of preparing CH3NH3PbBr3 QDs was also addressed. Notably, such a strategy can be applied extensively in the preparation of other lead halide perovskite QDs. Furthermore, the as-prepared thick PMMA-coated CH3NH3PbBr3 QDs were further conjoined with a red luminescence powder on a blue InGaN chip to obtain a powerful efficiency (45.4 lm W-1) warm white light-emitting diode.