Ambient Air Condition for Room-Temperature Deposition of MAPbI₃ Films in Highly Efficient Solar Cells

The power conversion efficiency of perovskite solar cells has been boosted rapidly, it has so far exceeded that of commercial polycrystalline silicon solar cells. This has prompted great interest in large-scale production and deployment of perovskite solar cells. However, state-of-the-art perovskite solar cells are fabricated inside gloveboxes and further annealing at high temperatures (typically at >100 °C for 30 min) is needed. These two required conditions are not compatible with, either in the respect to high-throughput or thermal budget, a feasible industrial production process. By eliminating the two requirements, the deposition of perovskite films both at room temperature and under ambient air condition will make the scalable roll-to-roll fabrication scheme feasible. Here, the anti-solvent (chloroform) washing is introduced to the previously developed hydrochloride-assisted method and demonstrate that the room-temperature method can be carried out under ambient air condition for MAPbI₃ film deposition. Through this new procedure, a power conversion efficiency as high as 17.72% is achieved for MAPbI₃ planar devices fabricated under a relative humidity of 30% at room temperature. Further, it is revealed that the room-temperature process MAPbI₃ films show a near monoexponential decay pathway with a long photoluminescence lifetime of >400 ns.