During the past years, the power conversion efficiency (PCE) of perovskite solar cells (PSCs) has increased from 3.8% to 25.7%, making them the best candidate for the next-generation photovoltaic devices. Two dominant PSC architectures have evolved, a regular n-i-p structure with mesoscopic or planar heterojunction and an inverted p-i-n planar structure. Compared to the regular n-i-p PSCs, the inverted p-i-n PSCs possess the advantages of lower synthesis temperature, no hysteretic effect and good compatibility with the tandem solar cells. For p-i-n PSCs, the hole transport layer (HTL) determines the hole transport efficiency and crystallinity of perovskite, so it plays a crucial role in the stacked devices. The conventional organic HTL of PEDOT:PSS-based PSCs can achieve satisfying PCEs, but may be able to impede the commercialization of perovskite photovoltaic devices because of their high price and acidity-induced poor stability. By comparison, the inorganic P-type NiOx with wide band gap exhibits low cost, superior chemical stability and high hole mobility without corrosion to perovskite layer. Unlike the most reported spin-coated NiOx nanoparticle films, we used sputtered NiOx as HTL for application in FA-based PSCs and achieved a PCE of 20.05%. After systematically optimizing the sputtering parameters, including power, time and argon flow rate, we obtained better crystal quality, better transparency, proper energy level, and higher hole mobility of NiOx film. Reducing the interstitial vacancies and defects in NiOx films attributes to decreased nonradiative recombination losses, which mainly cause the hole accumulation near the perovskite/NiOx interface. Finally, a champion device with open-circuit voltage (Voc) of 1.09 V, current density (Jsc) of 23.4 mA/cm², fill factor (FF) of 78% and PCE of 20.05% are obtained. This work has important significance for preparation of large-area perovskite solar cell modules.