Two-step sequential substrate vibration-assisted spray coating (SVASC) as a path to high performance perovskite solar cells

Efficiency of planar heterojunction CH3NH3PbI3-xClx solar cell is strongly influenced by the morphology and crystal size of the perovskite thin film. A novel approach using sequential spraying of the solution onto an ultrasonically vibrating substrate, i.e., two-step substrate vibration-assisted spray coating, (SVASC) is introduced and utilized for the fabrication of perovskite thin films. The perovskite crystal size, morphology and the percentage of coverage are significantly improved by imposing a 5 W ultrasonic vibration on the substrate. The perovskite thin films, prepared by the 2-step SVASC shows a 10% average improvement in light harvesting potential, compared to the thin films deposited on stationary substrates.