Superfast Room-Temperature Activation of SnO 2 Thin Films via Atmospheric Plasma Oxidation and their Application in Planar Perovskite Photovoltaics.

The power conversion efficiency (PCE) of perovskite solar cells (PSCs) has now exceeded 20%; thus, research focus has shifted to establishing the foundations for commercialization. One of the pivotal themes is to curtail the overall fabrication time, to reduce unit cost, and mass-produce PSCs. Additionally, energy dissipation during the thermal annealing (TA) stage must be minimized by realizing a genuine low-temperature (LT) process. Here, tin oxide (SnO ₂ ) thin films (TFs) are formulated at extremely high speed, within 5 min, under an almost room-temperature environment (<50 °C), using atmospheric Ar/O ₂ plasma energy (P-SnO ₂ ) and are applied as an electron transport layer of a "n-i-p"-type planar PSC. Compared with a thermally annealed SnO ₂ TF (T-SnO ₂ ), the P-SnO ₂ TF yields a more even surface but also outstanding electrical conductivity with higher electron mobility and a lower number of charge trap sites, consequently achieving a superior PCE of 19.56% in P-SnO ₂ -based PSCs. These findings motivate the use of a plasma strategy to fabricate various metal oxide TFs using the sol-gel route.
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