impact of plasma-coated sno₂ nanostructures on tio₂ surface for enhanced stability and performance of perovskite solar cells

In this study, hydrothermally synthesized sno₂ nanostructures deposited via a plasma-assisted process were employed as an interfacial modification layer in perovskite solar cells with an fto/tio₂/sno₂/ch₃nh₃pbi₃/au architecture. this low‑temperature interface engineering approach enables precise modification of the tio₂/perovskite interface without altering the bulk properties of the absorber layer. structural and spectroscopic analyses confirm the formation of a high‑purity sno₂ phase suitable for electron transport applications. the plasma‑assisted deposition facilitates the formation of a thin, uniform, and well‑adhered sno₂ interlayer under temperature conditions compatible with perovskite materials. as a result, the modified devices exhibit enhanced charge transport and extraction along with suppressed interfacial recombination. the optimized device delivers a power conversion efficiency of 20.7%, with an open‑circuit voltage (voc) of 1.09 v, a short‑circuit current density (jsc) of 21.3 ma cm⁻², and a fill factor (ff) of 89%, compared to a reference tio₂‑based device with a pce of 17.8%. these results demonstrate that plasma‑assisted deposition of sno₂ nanostructures provides a practical and scalable strategy for improving interfacial charge transport and photovoltaic performance in perovskite solar cells fabricated under ambient conditions.