Photoluminescence of Zero-Dimensional Perovskites and Perovskite-Related Materials

Abstract

Zero-dimensional (0-D) perovskites and perovskite-related materials are an emerging class of optoelectronic materials exhibiting strong excitonic properties and, quite often, high photoluminescence (PL) in the solid state. Here we highlight two different classes of 0-D perovskites with contrasting structural and optical properties, focusing mainly on the less explored but rapidly growing bulk quantum materials termed as 0-D perovskite-related materials (0-D PRMs), whose PL properties are quite intriguing and a topic of recent debate. We attempt to present here a comprehensive picture to rationalize the contrasting properties of the 0-D PRMs and provide an understanding of the mechanism of exciton dynamics and PL of this class of materials. We hope that exciting PL and tunable composition of these systems will help design of new materials with versatile optical properties suited for practical applications.

Single‐Solvent, Ligand‐Free, Gram‐Scale Synthesis of Cs4PbBr6 Perovskite Solids with Robust Green Photoluminescence

“…They generally exhibit only a sharp absorption peak at 314 nm and no luminescence under UV light. There are two different viewpoints for the origin of the green luminescence in Cs 4 PbBr 6 : one is that the green emission comes from the luminescent substances (i. e., CsPbBr 3 QDs) existed in Cs 4 PbBr 6 structures, the other is that it is caused by the structural defects (i. e., Br − vacancies, V Br ) or self‐trapping states (i. e., Pb 2 3+ ) of Cs 4 PbBr 6 . In the present work, it was worth noting that the paste‐like material harvested before the removal of DMF solution displayed a yellow‐green color and strong green emission, as shown in Figure S2.…”

“…So far, Cs 4 PbBr 6 perovskite materials with green luminescence have also been reported by several groups . It has been revealed that the green luminescence of these Cs 4 PbBr 6 perovskite materials is irrespective of the particle sizes and morphologies although their luminescent mechanism is still uncertain . Importantly, Cs 4 PbBr 6 is a lead depleted material in comparison with CsPbBr 3 .…”

“…[29][30][31] It has been revealed that the green luminescence of these Cs 4 PbBr 6 perovskite materials is irrespective of the particle sizes and morphologies although their luminescent mechanism is still uncertain. [38][39][40][41][42] Importantly, Cs 4 PbBr 6 is a lead depleted material in comparison with CsPbBr 3 . From the viewpoint of safety, it would be a boon to produce lead depleted perovskite materials whose properties match with lead-rich CsPbBr 3 QDs for the manufacturing of optoelectronic devices.…”

Photoluminescence Mechanisms of All‐Inorganic Cesium Lead Bromide Perovskites Revealed by Single Particle Spectroscopy

“…‐ The absence of the CsPbBr 3 phase was confirmed by fast Fourier transform (FFT) patterns from both bright and dark contrast regions which exhibit the same pattern along the <110> zone axis of Cs 4 PbBr 6 0D phase . The excitons are confined within [PbBr 6 4− octahedra as the [PbBr 6 4− ] octahedra are spatially isolated by intervening Cs atoms in the quasi‐0D structure . Consequently the confined structure leads to a high exciton binding energy, resulting in favorable radiative exciton recombination .…”

“…The emissive 0D Cs 4 PbBr 6 NCs have recently been demonstrated to act as single photon emitters . In a report by Seth et al, Cs 4 PbBr 6 microdisks exhibit strong green PL with QY up to ∼38% in the solid state . Fluorescence microscopy and lifetime imaging at the single particle level were utilized to reveal the spatial heterogeneity of the microdisks (Figure d–f).…”