Quantitative Investigation of Quantum Confined CSPBBr3 Nanocrystals to Further Understand Size-Dependent Properties

Abstract

The absorption cross section of lead halide perovskite nanocrystals is important for understanding their photophysical properties, especially those depending on the density of photoexcited charge carriers. Despite its importance, there are large discrepancies among the reported absorption cross section values determined employing different methods. Here, we measured the absorption cross section of CsPbBr3 quantum dots of varying sizes using elemental analysis and transient absorption (TA) saturation methods and compared with the previously reported values determined from elemental analysis and transient photoluminescence (PL) saturation methods. Careful comparison indicates that the reliable absorption cross section of lead halide perovskite QDs are obtained from both elemental analysis and TA saturation methods, while many previously reported values determined from the PL saturation method underestimate the absorption cross section. This work further quantifies properties of the CsPbBr3 material to allow for further ease in predicting the material’s behavior when quantum confined and shows further application of transient absorption methodologies to understand the excitonic properties and processes exhibited.