Ultrasmall CsPbBr3 Blue Emissive Perovskite Quantum Dots Using K-Alloyed Cs4PbBr6 Nanocrystals as Precursors

• DOI: 10.1021/acsenergylett.4c00693
• Publication Date: 2024-04-23T20:13:55Z
• Authors: Clara Otero-Martínez; Matteo L. Zaffalon; Yurii P. Ivanov; Nikolaos Livakas; Luca Goldoni; Giorgio Divitini; Sankalpa Bora; Gabriele Saleh; Francesco Meinardi; Andrea Fratelli; Sudip Chakraborty; Lakshminarayana P...; Sergio Brovelli; Liberato Manna
• Keywords: Quantum yield; Auger effect

We report a colloidal synthesis of blue emissive, stable cube-shaped CsPbBr3 quantum dots (QDs) in the strong confinement regime via dissolution-recrystallization starting from pre-synthesized (KxCs1-x)4PbBr6 nanocrystals which are then reacted with PbBr2. This is markedly different known case Cs4PbBr6 that react within seconds PbBr2 and get transformed into much larger, green emitting nanocrystals. Here, instead, conversion to QDs occurs time span hours, tuning size achieved by adjusting concentration precursors. The exhibit excitonic features optical absorption tunable 420 - 452 nm range, accompanied photoluminescence yield around 60%. Detailed spectroscopic investigations both single multi-exciton reveal exciton fine structure effect Auger recombination these QDs, confirming theoretical predictions for this system.