Ni-Doped SnO₂ as an Electron Transport Layer by a Low-Temperature Process in Planar Perovskite Solar Cells

Perovskite solar cells (PSCs) based on a planar structure have recently become more attractive due to their simple manufacturing process and relatively low cost, while most perovskite solar cells employ highly porous TiO₂ as an electron transport layer in mesoporous devices offering higher energy conversion efficiency (PCE). In planar structural devices, non-radiative recombination effects of the absorber layer and the electron transport layer cause potential loss and lower PCE. We created an efficient electron transport layer by combining low-temperature Ni-doped SnO₂ with SDBS as a surfactant (denoted as Ni:SnO₂). Doping Ni⁺ into low-temperature solution-processed SnO₂ increased the power conversion efficiency of PSCs from 17.8 to 19.7%.