Fig. 2.

Characterization of the Alfa–SnO₂ and corresponding performance of PSCs. a The STEM–EDX images of the Alfa–SnO₂ colloidal. b The corresponding EDX spectra consistent to the boxed area. c The normalized SIMS results of the CsFAMA perovskite deposited on Alfa–SnO₂/FTO substrate. d The XPS spectra of K2p orbital of the pristine Alfa–SnO₂ films and Water Alfa–SnO₂ films. e The SEM images of Alfa–SnO₂ based CsFAMA perovskite film, f Water Alfa–SnO₂-based CsFAMA perovskite film and g KOH-treated Water Alfa–SnO₂-based CsFAMA perovskite film. h The J-V curves of Alfa–SnO₂-based PSC, i Water Alfa–SnO₂-based PSC and j KOH-treated Water Alfa–SnO₂-based PSC, respectively