One-Pot Synthesis of All-Inorganic CsPbClBr₂ Blue Perovskite Quantum Dots via Stoichiometric Precursor

Abstract

The synthesis of perovskite-based blue lightemitting particles is valuable for several applications as the excellent optical properties and performances of the constituting materials associated with multi-exciton generation can be exploited. However, the preparation of perovskite precursors requires high temperatures, resulting in a complex manufacturing process. This paper proposes a one-pot method to synthesize CsPbClBr 2 blue light-emitting quantum dots (QDs). In the case of nonstoichiometric precursor synthesis, the CsPbClBr 2 QDs coexisted with additional products. The solvent for synthesizing mixed perovskite nanoparticles (containing chloride) was selected by mixing dimethylformamide (DMF) and/or dimethyl sulfoxide (DMSO) in different ratios. When only DMF was used with the stoichiometric CsBr and PbX 2 (X = Cl, Br) ratio, the quantum yield was 70.55%, and superior optical properties were achieved. Moreover, no discoloration was observed for 400 h, and a high photoluminescence intensity was maintained. When deionized water was added to form a double layer with hexane, the luminescence was maintained for 15 days. In other words, the perovskite did not easily decompose even when in contact with water, which suppressed the release of Pb 2+ , which are heavy metal atoms in the structure. Overall, the proposed one-pot method for all-inorganic-based perovskite QDs provides a platform for synthesizing superior blue light-emitting materials.

Surface defect mitigation via alkyl-ligand-controlled purification for stable and high-luminescence perovskite quantum dots

“…Additionally, the relative QY of the MeOAc-treated PQDs was confirmed. The QY value of PQDs relative to the standard solution of rhodamine B in ethanol (QY = 65%) was calculated using eqn (1): 55 where Φ is the QY, F is the absorption factor, A is the area of the fluorescence spectrum at the point of equal concentration, n is the refractive index of the solvent, Grad indicates the gradient, and the subscripts st and x indicate rhodamine B and the MAPbBr 3 QDs, respectively. Here, the refractive indices of ethanol and hexane are 1.370 and 1.375, respectively.…”

Eliminating Chlorine Vacancies of Perovskite Nanocrystals Using Hydrazine Cations Enables Efficient Pure Blue Light-Emitting Diodes

“…These findings confirm that Hz 2+ does not disrupt perovskite crystals or enter NCs but instead covers NCs, suggesting that the interaction between Hz 2+ and the perovskite, as confirmed by FTIR, is surface adsorption. Lastly, the FTIR peak near 2920 cm –1 corresponds to the −C–H– vibration of DDA + , acting as a long-chain ligand to maintain the stability of NC dispersion . TBAC, used solely as a chlorine source, exhibits substantial steric hindrance in its cationic part, impeding surface adsorption (Figure S3).…”