Fluorescent Phase-Pure Zero-Dimensional Perovskite-Related Cs₄PbBr₆ Microdisks: Synthesis and Single-Particle Imaging...

Quantum-confined perovskites are a new class of promising materials in optoelectronic applications. In this context, a zero-dimensional perovskite-related substance, Cs₄PbBr₆, having high exciton binding energy can be an important candidate, but its photoluminescence (PL) is a topic of recent debate. Herein, we report an ambient condition controlled synthesis of Cs₄PbBr₆ microdisks of different shapes and dimensions which exhibit fairly strong green PL (quantum yield up to 38%, band gap ∼2.43 eV) in the solid state. Using confocal fluorescence microscopy imaging of the single particles, we show that the fluorescence of Cs₄PbBr₆ microdisks is inherent to these particles. Fluorescence intensity and lifetime imaging of the microdisks reveals significant spatial heterogeneity with a bright central area and somewhat dimmer edges. This intensity and lifetime distribution is attributed to enhanced trap-mediated nonradiative deactivation at the edges compared to the central region of the microdisks. Our results, which unambiguously establish the PL of these Cs₄PbBr₆ and suggest its possible origin, brighten the potential of these materials in photon-emitting applications.