A Comparative Study of SnO₂ Deposition Using Spray and Spin-Coating Technique for Electron Transport Layer of Inorganic Perovskite Solar Cells

Organic-inorganic halide perovskites have become notable for their efficiency in light harvesting. Nonetheless, the incorporation of organic cations like $\mathbf{M A}^{+}$and $\mathrm{FA}^{+}$presents stability challenges when exposed to environmental factors. This study explores the potential of replacing organic components with inorganic $\mathrm{Cs}^{+}$to enhance stability and efficiency in PSCs, focusing on CsPbBr<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> as the light harvester. We compare spin-coating and spray-coating techniques for depositing SnO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> as the electron transport layer, revealing that spray-coating 7 cycles achieves higher PCE. Through detailed characterization, including UV-Vis, FTIR, SEM, I-V, and IPCE analyses, we optimized the manufacture of $\mathrm{SnO}_{2}, \mathrm{CsPbBr}_{3}$, and carbon deposition at room temperature, resulting in a PCE of $\mathbf{2. 2 1 \%}$ using the spray-coating process, demonstrating significant improvements over the spin-coating method.