High-quality NiO thin film by low-temperature spray combustion method for perovskite solar cells

As a potential hole transport material for perovskite solar cells, nickel oxide presents attractive properties in stability and price. However, in most cases, NiO thin films are prepared in high temperature, which is not suitable for the wide application of perovskite solar cells. In this work, we proposed to fabricate NiO thin films at relatively low temperature by spray combustion method, which performed better than that by spin-coating method. The optimal ratio of nickel nitrate to acetylacetone, combustion induced temperature, and spraying volume of precursor were completely investigated. Based on these conditions, we obtained a uniform and dense NiO thin film with proper thickness, which were further employed as hole transport film for invert perovskite solar cell. A highest efficiency of 12.7% was achieved for perovskite solar cells. Moreover, a stable current output at 0.8 V in 300 s was observed in the best-performing perovskite solar cell. In a word, this work demonstrated a facial method to get NiO thin film in low temperature which was good for the further research of perovskite solar cells. •A new spray combustion method was used to prepare NiO thin film in low temperature.•The prepared NiO film was dense and thickness controllable.•The inverted PSC got an efficiency of 12.7% and good working stability.