Effect of different surface treatments of sputtered NiO X on the photovoltaic parameters of perovskite solar cells: a correlation study

Understanding the surface chemistry of sputtered (sp) nickel oxide (NiOx) hole transporting layer and its influence on the perovskite photovoltaic properties is crucial in aiding improved device performance. Herein, the influence of (1) as-deposited, (2) 2-propanol (IPA) dipping, (3) UV-ozone and (4) plasma treated sp-NiOx on the perovskite device performance is compared. Surface treatment not only changes the work function and surface wettability of sp-NiOx but also enhances the perovskite quality and its device performance. Perovskite device with plasma treatment yielded the best efficiency owing to hydrophilic sp-NiOx surface, deep-lying valance band, and suppressed recombination in bulk of perovskite.