Optimizing optical properties of hybrid core/shell perovskite nanocrystals†
Abstract
Hybrid perovskite nanocrystals (NCs) are widely used in various applications, due to their desirable optoelectronic characteristics. However, the related applications are usually hindered by their poor long-term stability. In this work, we have synthesized one kind of CH3NH3PbBr3 (MAPbBr3) NC that is heteroepitaxially grown with an MA1−xCsxPbBr3 shell, with the aim to optimize the optical properties of the former. It is found that the MAPbBr3/MA1−xCsxPbBr3 core/shell NCs possess optimized optical stability. Through the measurement of the temperature-dependent photoluminescence spectrum, it is confirmed that the core/shell NCs exhibit weaker electron–phonon coupling strength and larger exciton binding energy than the bare MAPbBr3 NCs. Interestingly, the core/shell NCs display significantly prolonged biexciton Auger lifetime and enlarged two-photon absorption. Impressively, two-photon pumped amplified stimulated emission is only observed in the core/shell NCs but not in the bare NCs, enabling the former to be promising for application in nonlinear optoelectronic devices.