CNC assisted spray deposition of large grain size CH3NH3PbI3 film for perovskite solar cells

This work presents a utilization of spray deposition technique in the fabrication of thin film perovskite solar cell devices with an assistance of a homemade CNC machine. An 80nm-thick compact TiO2 was sprayed at a substrate temperature of 400 degrees C for electron blocking layer. Both one and two-step spray deposition technique are used to compare the quality of the perovskite absorber layer. A large grain size and voids free CH3NH3PbI3 film achieved by using the two-step spray deposition process. When such films are incorporated into a solar cell device with conductive carbon counter electrode, the maximum power conversion efficiencies of up to 9.58% are realized. This approach could pave the way to develop low-cost perovskite solar cell.