The photovoltaic performance of low temperature paintable carbon-based perovskite solar cells (LC-PSCs) was improved significantly by inserting a NiO nanocrystal-carbon (NiO-C) intermediate layer between the perovskite and carbon electrode. Finally, a champion efficiency of 12.5% in a large active area of 1 cm(2) was demonstrated in LC-PSCs with NiO-C intermediate layer, which originated from enhanced hole extraction and transport, reduced carrier recombination and improved energy level alignment. Meanwhile, ultrahigh ambient stability of LC-PSCs was further improved by modifying with NiO-C.