Uniform perovskite photovoltaic thin films via ultrasonic spray assisted deposition method

We reported a fast and controllable two step deposition method for fabricating perovskite solar cells. Homogeneous perovskite CH3NH3PbI3 thin film layers were deposited by thermal evaporation of PbI2 and ultrasonic spray coating of CH3NH3I. The use of ultrasonic spray coating technique ensured a better control of the perovskite morphology, and a complete reaction for forming the CH3NH3PbI3 layer in the air atmosphere. The resulted devices exhibited a PCE of ∼7.7% without a significant hysteresis under AM 1.5G conditions.