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

Abstract

Synthesisof all-inorganic perovskite quantum dots usinga stoichiometric precursor in a one-pot method without a thermal environmentis very advantageous in terms of the crystal structure of the materials.Additional products due to nonstoichiometric precursors act as impurities,leading to particle aggregation and collapse of the crystal structure. The synthesis of perovskite-based blue light-emittingparticlesis valuable for several applications as the excellent optical propertiesand performances of the constituting materials associated with multi-excitongeneration can be exploited. However, the preparation of perovskiteprecursors requires high temperatures, resulting in a complex manufacturingprocess. This paper proposes a one-pot method to synthesize CsPbClBr2 blue light-emitting quantum dots (QDs). In the case of nonstoichiometricprecursor synthesis, the CsPbClBr2 QDs coexisted with additionalproducts. 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 DMFwas used with the stoichiometric CsBr and PbX2 (X = Cl,Br) ratio, the quantum yield was 70.55%, and superior optical propertieswere achieved. Moreover, no discoloration was observed for 400 h,and a high photoluminescence intensity was maintained. When deionizedwater was added to form a double layer with hexane, the luminescencewas maintained for 15 days. In other words, the perovskite did noteasily decompose even when in contact with water, which suppressedthe release of Pb2+, which are heavy metal atoms in thestructure. Overall, the proposed one-pot method for all-inorganic-basedperovskite QDs provides a platform for synthesizing superior bluelight-emitting materials.