Study on Optical and Electrical Properties of Thermally Evaporated Tin Oxide Thin Films for Perovskite Solar Cells

Perovskite solar cells were fabricated with SnO2 thin films as a window layer and electron transport layer by thermal evaporation. Fundamental characteristics of SnO2 thin films to determine the performance of solar cells were investigated in an optical and electrical manner, varying annealing temperatures. It is found the crystallinity and the presence of localized energy states play a key factor to control the properties of SnO2. In addition, XPS was used to confirm the stoichiometry of the SnO2 thin films, indicating a better charge collection on the annealed SnO2 samples. The SnO2 thin films annealed at 300 °C exhibited desirable optical and electrical properties for the enhanced performance of solar cells. The results show that thermally evaporated SnO2 thin films can be precisely engineered and controlled for mass production and more practical industrialization of perovskite solar cells.