Optimizing the Distribution of Additive to Refine the Micro-Nanostructure of Perovskite Films via Pulsed Laser Processing

Additives have found widespread application in perovskite optoelectronic devices, playing a crucial role in enhancing the performance and stability of these devices by optimizing the crystallization kinetics of the perovskite. However, the nonuniform distribution of additives in perovskite films caused by the bottom-up volatilization of low-boiling-point additives during traditional thermal annealing is a challenging issue that needs to be solved. In this work, we propose a strategy that integrates laser processing technology with the dithieno[3,2-b:2',3'-d]thiophene (DTT) additive process, which enables it to reduce defects by interacting with the octahedral inorganic framework of perovskite. Initially, the micro-nanostructure of the perovskite film is enhanced by the fast crystallization induced by high-energy pulsed laser irradiation, which in turn modulates the evaporation of the solution to regulate the distribution of DTT. Concurrently, the shock pressure generated by the pulsed laser further restricts the accumulation of DTT and promotes its uniform distribution within the perovskite film. As a result, by optimizing the crystallization kinetics of perovskite through pulsed laser and DTT, the crystal structure and electronic structure optimization of perovskite film lead to a reduction in defect density. The optimization of carrier dynamics further enhances the performance of the device with an excellent T₈₀ stability of about 2400 h. This approach will provide a technical framework and theoretical basis for controlling the perovskite crystal growth and defect passivation to achieve large-scale commercial applications.