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

Yu, Haejun; Yeom, Hye-In; Lee, Jong Woo; Lee, Kisu; Hwang, Doyk; Yun, Juyoung; Ryu, Jaehoon; Lee, Jungsup et al. · Adv Mater · 2018

basic_science · Level V

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Abstract

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<sub>2</sub> ) thin films (TFs) are formulated at extremely high speed, within 5 min, under an almost room-temperature environment (<50 °C), using atmospheric Ar/O<sub>2</sub> plasma energy (P-SnO<sub>2</sub> ) and are applied as an electron transport layer of a "n-i-p"-type planar PSC. Compared with a thermally annealed SnO<sub>2</sub> TF (T-SnO<sub>2</sub> ), the P-SnO<sub>2</sub> 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<sub>2</sub> -based PSCs. These findings motivate the use of a plasma strategy to fabricate various metal oxide TFs using the sol-gel route.