Composition-tuned MAPbBr 3 nanoparticles with addition of Cs + cations for improved photoluminescence.

Hybrid organic-inorganic lead halide perovskite nanoparticles are promising candidates for optoelectronic applications. This investigation describes the structural and optical properties of MA x Cs 1- x PbBr 3 mixed cation colloidal nanoparticles spanning the complete compositional range of Cs substitution. A monotonic progression in the cubic lattice parameter ( a ) with changes in the Cs + content confirmed the formation of mixed cation materials. More importantly, time-resolved photoluminescence (TRPL) revealed the optimized 13 mol% Cs nanoparticle composition exhibits the longest charge carrier lifetime and enhancement in radiative pathways. This sample also showed the highest photoluminescence quantum yield (PLQY) of ∼88% and displays ∼100% improvement in the PLQY of pure MAPbBr 3 and CsPbBr 3 . Prototype LEDs fabricated from MA 0.87 Cs 0.13 PbBr 3 were demonstrated.