Advances in perovskite solar cells: Film morphology control and interface engineering

As a new clean renewable energy, Perovskite solar cells (PSC) has become a research hotspot. The multi-step diffusion method can effectively control the composition and proportion of the precursor liquid, regulate the crystallization process and the final morphology of the perovskite film, thereby obtaining a smooth and dense high-quality perovskite film; The introduction of micro-Mg element makes the Fermi energy level of TiO₂ electron transport layer move up, enhances conductivity, and reduces surface defect states. Correspondingly, after Mg doping, the series resistance of planar perovskite battery decreases, the electron transmission speed becomes faster, and the charge collection efficiency is improved under high bias voltage; In the process of deposition of perovskite film by one-step inverse solvent method, polystyrene (PS) is introduced to cover the surface of polycrystalline perovskite film and fill the grain boundary to form a protective layer covering single grain. On the one hand, PS coating can effectively inhibit the volatilization and phase separation of organic components in perovskite films at high temperature, and maintain the stability of film components and phase, on the other hand, PS coating can effectively prevent the corrosion of perovskite film by water, and improve the moisture stability and self-repair ability of the film. In addition, since the self-adhesive porous carbon has good flexibility, compressibility, and adhesion to the electrode, it can be applied to perovskite solar cells. After the pressure is transferred, the carbon counter electrode can form an excellent interface contact with the hole transport layer, which promote the interface charge extraction and solve the interface contact problem existing in carbon-based perovskite batteries for a long time. The purpose of the paper is to provide the basis for exploring the technology of PSCs preparation on a large scale.