High-yield synthesis of CsPbBr3 nanoparticles: diphenylphosphine as a reducing agent and its effect in Pb-seeding nucleation and growth

Abstract

Based on the reported nucleation mechanisms for CsPbX3 and II–VI/IV–VI quantum dots, CsPbBr3 nanoparticles with a higher reaction-yield (up to 393% mass-increment) were synthetized by the hot-injection method. The introduction of diphenylphosphine (DPP) as a reducing agent improved nanoparticle nucleation and growth, giving out evidence for Pb-seeding in CsPbBr3 nanoparticles formation. Additionally, a clear influence of the DPP in a CsPbBr3-Cs4PbBr6 incomplete phase transformation was observed, marked by the appearance of several PbBr2 nanoparticles. This indicated the need for an improved ratio between the stabilizing agents and the precursors, due to the increased number of nucleation sites produced by DPP. The resulting CsPbBr3 nanoparticles showed high quality, as they displayed 70%–90% photoluminescence quantum yield; narrow size distribution with an average nanoparticle size of ∼10 nm; and the characteristic cubic morphology reported in previous works. This increment in CsPbBr3 nanoparticles’ reaction yield will contribute to making them a more attractive option for different optoelectronic applications.