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.