High Efficiency over 20% of Perovskite Solar Cells by Spray Coating via a Simple Process

The development of perovskite solar cells (PSCs) has progressed rapidly because of their high efficiency and low cost. The performance of PSCs is predominantly determined by the quality of the perovskite films, which is controlled by the fabrication process. The comprehensive and in-depth understanding of the nucleation, crystallization, and growth process are imperative for the further advancement of large-scale manufacturing of high-quality perovskite films. In this work, the simple process parameters of perovskite thin films were systematically optimized at ambient air, such as containing the thickness of the perovskite thin film, the anti-solvent bath, and the thermal annealing time. Through these simple processes, the wet film, solvent volatilization, and crystallization of perovskite films can be controlled and optimized. After optimizing the spraying conditions, the champion power conversion efficiency (PCE) of the PSCs achieved 20.6% (reverse scan) and had little hysteresis in the current density–voltage (J–V). In addition, the unsealed device retained 85% of its original PCE and showed excellent long-term stability after 650 h of storage in the drying tower.