Fully slot-die-coated perovskite solar cells in ambient condition

Organic–inorganic hybrid perovskite solar cells (PSCs) are developing rapidly, but most of the PSCs are prepared by spin coating process, which is not compatible with potential large-scale, high-throughput industrialization. Slot-die coating is a promising deposition technique with high precision and excellent material utilization, which can accelerate the industrial-scale production of PSCs and enhance the potential commercial value. Herein, fully slot-die-coated PSCs were achieved by subsequently slot-die coating electron transport layer, perovskite layer and hole transport layer in ambient condition, leading to a power conversion efficiency (PCE) up to 14.55%. The optimization of slot-die coating parameters for two-step deposition process can produce even PbI2 film and subsequent high-quality perovskite film. Furthermore, a mixed solvent of dimethyl sulfoxide and N, N-dimethylformamide was used to dissolve PbI2 for further enhancing the surface energy and delaying crystallization, leading to a uniform and better perovskite film. In addition, the slot-die coating properties and repeatability could be improved by adding a small quantity of cations (cesium, methylammonium and formamidinium) additives into the PbI2 precursor solution. The results suggest that efficient PSCs with good repeatability could be processed via fully slot-die coating in ambient condition, which is compatible with potentially large-scale, roll-to-roll commercial process.