Comprehensive studies of air-brush spray deposition used in fabricating high-efficiency CH₃NH₃PbI₃ perovskite solar cells: Combining theories with practices

Organic-inorganic perovskite solar cells (PSCs) are among the most attractive and efficient emerging thin film photovoltaic technologies. The perovskite films have been fabricated by lots of deposition methods, including one-step/two-step spin coating, thermal evaporation and vapor assisted processes. However, the laboratory-based fabrication methods are not well matched with large area manufacture for actual use. Spray coating deposition technique is being explored to prepare perovskite films to break the bottleneck plaguing large scale production. Herein, a comprehensive study is conducted in fabricating perovskite films by air-brush spraying method. The spraying process is classified into three stages, namely, 1) atomization process, 2) droplet flight and 3) film deposition. Each of them is discussed in detail from principles to parameters. Integrating the three aspects above, high quality perovskite films comparable to spin coated films are obtained. A best power conversion efficiency (PCE) of 16.68% is achieved for planar structure PSCs, which is prominent among the PSCs fabricated by spraying method. In addition, devices with spraying method show excellent optical and electrical properties. The principles we discuss here could be applied in the actual condition for mass production.