Grain Characteristics of Perovskite Thin Films Based on SEM Image Segmentation

Perovskite solar cells (PSCs) have become the forefront and hot pot of new photovoltaic technology due to their high efficiency, low cost, and easy preparation. Understanding the microstructure characteristics of the perovskite films is one of the key factors to further improve the efficiency and stability. The characteristics of grains based on the self-developed perovskite film morphology analysis software GrainD are studied in this article. Important perovskite film information such as the average radius of grains, the distribution pattern of grain size, the area of grain contact, and the total number of grains are obtained. The results show that the grain size distribution of the polycrystalline perovskite film follows the lognormal distribution. According to statistical probability theory and grain growth theory, the multiplication effect of multiple random factors of film growth is proposed as the reason for the lognormal distribution. This study provides an important method for analyzing the perovskite films and gives clues about the crystallization kinetics.