Highly Reproducible Large‐Area Perovskite Solar Cell Fabrication via Continuous Megasonic Spray Coating of CH₃NH₃PbI₃

Abstract

A simple, low-cost, large area, and continuous scalable coating method is proposed for the fabrication of hybrid organic-inorganic perovskite solar cells. A megasonic spray-coating method utilizing a 1.7 MHz megasonic nebulizer that could fabricate reproducible large-area planar efficient perovskite films is developed. The coating method fabricates uniform large-area perovskite film with large-sized grain since smaller and narrower sized mist droplets than those generated by existing ultrasonic spray methods could be generated by megasonic spraying. The volume flow rate of the CH₃ NH₃ PbI₃ precursor solution and the reaction temperature are controlled, to obtain a high quality perovskite active layer. The devices reach a maximum efficiency of 16.9%, with an average efficiency of 16.4% from 21 samples. The applicability of megasonic spray coating to the fabrication of large-area solar cells (1 cm² ), with a power conversion efficiency of 14.2%, is also demonstrated. This is a record high efficiency for large-area perovskite solar cells fabricated by continuous spray coating.