Room-temperature electrochemically deposited polycrystalline SnO2 with adjustable work function for high-efficiency perovskite solar cells

Abstract

In the last two years, studies on SnO₂ preparation and optimization have proved to be effective paths toward the Schottky limit of perovskite solar cells. Herein, we used an electrochemical deposition method to obtain polycrystalline SnO₂ film at room temperature for the first time. The method has the advantage of simplicity and efficiency using electrochemistry to realize deposition, adsorption, and protection of the SnO₂ film, avoiding a more complex regulation process than the chemical bath deposition method. Benefiting from the optimization process, the method could achieve adjustable work function of the SnO₂ film by controlling the pH of the electrolyte, which is conducive for reducing mismatched energy levels between the SnO₂ film and the perovskite layer. Besides, the obtained SnO₂ film is densely and uniformly distributed along the substrate profile, leading to better light transmission. More importantly, this method can be applied to prepare SnO₂ film on large area and flexible substrates. Finally, the device based on SnO₂ film prepared with pH = 1 electrolyte achieves the highest performance of 22.85%, which is higher than that of the device based on the commercial colloidal dispersion SnO₂ film (21.72%). These multi-advantages of the method make it competitive for future commercialization.