Size- and Morphology-Dependent Auger Recombination in CsPbBr3 Perovskite Two-Dimensional Nanoplatelets and One-Dimensional Nanorods.

Abstract

CsPbX3 (X = Cl, Br, I) perovskite nanocrystals (NCs), including zero-dimensional (0D) quantum dots (QDs), one-dimensional (1D) nanorods (NRs), and two-dimensional (2D) nanoplatelets (NPLs), have shown promising performances in light-emitting diode (LED) and lasing applications. However, Auger recombination, one of the key processes that limit their performance, remains poorly understood in CsPbX3 2D NPLs and 1D NRs. We show that the biexciton Auger lifetimes of CsPbBr3 NPLs (NRs) scale linearly with the NPL lateral area (NR length) and deviates from the "universal volume scale law" that has been observed for QDs. These results are consistent with a model in which the Auger recombination rate for 1D NRs and 2D NPLs is a product of binary collision frequency in the nonquantum confined dimension and Auger probability per collision. Comparisons of Auger recombination in CsPbBr3 NCs of different dimensionalities and similar band gaps suggest that Auger probability increases in NCs with a higher number of confined dimensions. Compared to CdSe and PbSe NCs with the same dimensionalities and similar sizes, Auger recombination rates in 0D-2D CsPbBr3 NCs are over 10-fold faster. Fast Auger recombination in CsPbBr3 NCs shows their potentials for Auger-assisted up-conversion and single photon source, while suppressing Auger recombination may further enhance their performances in LED and lasing applications.