Perovskite Solar Cells Using Surface‐Modified NiOx Nanoparticles as Hole Transport Materials in n‐i‐p Configuration

Modified NiOx nanoparticles (NPs) developed via surface engineering are applied to a hole transport layer (HTL) in n‐i‐p‐structured perovskite solar cells (PSCs). Hexanoic acid (HA) as a surfactant improves the dispersibility of NiOx NPs in chlorobenzene (CB). The conductivity of the NiOx‐HA film is 1.20×10−5S cm−1, which is superior to that of 2,2′,7,7′‐tetrakis(N,N‐di‐p‐methoxyphenyl‐amine)‐9,9′‐spirobifluorene (spiro‐OMeTAD) with dopants. The NiOx‐HA film shows better hole extraction properties compared with the pristine NiOx film. The NiOx‐HA NPs form closely packed and pinhole‐free films, leading to improved device performance with a power conversion efficiency from 5.5% to 13.1%. Surface‐modified NiOx nanoparticles (NPs) as hole transport materials in n‐i‐p‐structured perovskite solar cells are studied. The modified NiOx NPs disperse well in chlorobenzene, and their film forms smooth and pinhole‐free layers, which show good electrical conductivity and improved extraction properties. The power conversion efficiency is improved from 5.5% to 13.1%.