CH3NH3I treatment temperature of 70 °C in low-pressure vapor-assisted deposition for mesoscopic perovskite solar cells

Highlights: • The perovskite films was prepared by vapor-assisted deposition method. • The CH₃NH₃I treatment temperature was reduced to 70 °C in the modified method. • MAI powder sublimated and reacted with PbI₂ layer for preparing CH₃NH₃PbI₃ films. Herein, we report a modified vapor-assisted deposition method to fabricate CH₃NH₃PbI₃ film at 70 °C in a vacuum drying oven. The modified method has excellent operability and expandability in preparing perovskite solar cells. The CH₃NH₃I treatment temperature is 130 °C or 150 °C in conventional method, but we reduced the temperature to 70 °C in the modified vapor-assisted method. Meanwhile, the quality of CH₃NH₃PbI₃ films prepared via the modified method is superior to that of CH₃NH₃PbI₃ films of solution-processed method.