Reactive e-beam evaporated SnOx layer as an effective ETL for highly efficient spray-coated perovskite solar cells

Abstract

The spray-coating deposition method can extend the use of perovskite solar modules to substrates with different shapes and curvatures that can be used in various parts of buildings and vehicles to maximize the use of solar energy. Due to the lack of centrifugal forces in this method, unlike spin-coating, the quality of the deposited perovskite layer highly depends on the wettability and uniformity of the under layer. In this project, the SnOx layer is deposited by the reactive electron beam evaporation method (re-SnOx) as an electron transport layer for the spray-coated Cs0.05FA0.81MA0.14PbI2.55Br0.45 layer. Results show that spray-coated perovskite (PSK) layers are significantly more uniform on re-SnOx layers compared to the spin-coated commercial nanoparticles of SnOx (np-SnOx) due to their excellent surface coverage and purity. The best efficiency of 20.8% is obtained for re-SnOx/spray-coated PSK. Surface passivation of spray-coated PSK with phenethylammonium iodide improves all photovoltaic properties, increases efficiency from an average of 17.9%–19.6%, and reduces the hysteresis index from an average of 0.3 to 0.09. This low-temperature structure can be fabricated on plastic substrates, as well.