In recent years, perovskite solar cells have emerged as a bright star in the realm of renewable energy, capturing the attention of researchers and industry experts with their high conversion efficiencies, low costs, and exceptional flexibility. Despite these advantages, the Achilles' heel of perovskite solar cells lies in the delicate art of film preparation. The challenges inherent in this process, if not overcome, could potentially hinder the technology's march towards commercialization. This paper delves into a critical aspect of perovskite film formation—the deposition of the PbI₂ seed layer in the two-step synthesis of perovskite materials. The seed layer, serving as the cornerstone for the growth of the perovskite lattice, plays a decisive role in the ultimate performance of the solar cell. Inspired by the role of SnCl₂ in the silver mirror reaction, this paper proposes the use of an SnCl₂ sensitization layer to enhance the adsorption capacity of PbI₂ particles on TiO₂ substrates. To validate this hypothesis, we conducted a series of molecular dynamics simulations. These simulations provided a microscopic perspective on the deposition process, contrasting the adsorption and deposition behaviors of PbI₂ particles on pristine TiO₂ surfaces with those on TiO₂ surfaces pre-treated with SnCl₂. The findings indicated that the substrate sensitized with SnCl₂ could significantly reduce the energy of PbI₂ particles during the deposition process, facilitating their adsorption and deposition on the substrate.To further analyze the binding energies among SnCl₂, PbI₂, and TiO₂, additional simulations focused on their interactions. These simulations confirmed that SnCl₂ could act as an effective bridge, promoting a tighter bond between PbI₂ and TiO₂. Complementing the simulations, experimental validation was carried out through PbI₂ solution deposition. The resulting films, analyzed using scanning electron microscopy (SEM) and X-ray diffraction (XRD), confirmed the positive impact of the SnCl₂ sensitization layer on the quality of PbI₂ film deposition.

Key words: perovskite solar cells, film, "bridge" particles, induced adsorption