Spray-Cast Multilayer Organometal Perovskite Solar Cells Fabricated in Air

Spray-coating is a versatile coating technique that can be used to deposit functional films over large areas at speed. Here, spray-coating is used to fabricate inverted perovskite solar cell devices in which all of the solution-processible layers (PEDOT:PSS, perovskite, and PCBM) are deposited by ultrasonic spray-casting in air. Using such techniques, all-spray-cast devices having a champion power conversion efficiency (PCE) of 9.9% are fabricated. Such performance compares favorably with reference devices spin-cast under a nitrogen atmosphere that has a champion PCE of 12.8%. Losses in device efficiency are ascribed to lower surface coverage and reduced uniformity of the spray-cast perovskite layer.