Unraveling the Growth Kinetics via In Situ Photoluminescence and Carrier Dynamics via Transient Absorption in CsPbBr 3 Nanocrystals

Elucidating and controlling the crystallization process through in situ detection are vital for the preparation of high-performance photovoltaic materials. In this study, zero-dimensional nanocluster seeds and two-dimensional/three-dimensional (2D/3D) CsPbBr 3 hybrid assemblies were synthesized using a “two-step hot injection” method, and the structures of the products can be well controlled by adjusting the reaction temperatures. In situ photoluminescence spectroscopy monitoring of CsPbBr 3 nanocrystal growth clearly reveals anisotropic growth kinetics across three distinct stages. Specifically, femtosecond transient absorption spectroscopy was employed to analyze the photoinduced carrier dynamics of intermediate products, identifying complex processes such as defect state generation and passivation as well as the formation of hybrid homogeneous assemblies during growth. The carrier lifetime of hybrid homogeneous assemblies is extended to 2170 ps, 11 times longer than that of pristine nanocrystals (188.9 ps). This work provides significant insights into the preparation and control of perovskite nanomaterials.