In situcell-scale probing nucleation, growth and evolution of CsPbBr₃nanowires by optical absorption spectroscopy

The growth kinetics of colloidal lead halide perovskite nanomaterials are an integral part of their applications, remains poorly understood due to complex nucleation processes and lack ofin situsize monitoring method. Here we demonstrated that absorption spectra can be used to observein situgrowth processes of ultrathin CsPbBr₃nanowires in solution with reference to the effective mass infinite deep square potential well model. By means of this method, we have found that the ultrathin nanowires, fabricated by hot injection method, were firstly formed within one minute. Subsequently, they merge with each other into a thicker structure with increasing reaction time. We revealed that the nucleation, growth, and merging of the CsPbBr₃nanowires are determined by the acid concentration and ligand chain length. At lower acidity, the critical nucleation size of the nanowire is smaller, while the shorter the ligand chain length, the faster the merging among the nanowires. Moreover, the merging mode between nanowires changed with their nucleation size. This growth kinetics of CsPbBr₃nanowires provides a reference for optimizing the synthesis conditions to obtain the one-dimensional CsPbBr₃with desired size, thus enabling accurate control of the nanowire shape.