Enhanced Efficiency of Hot-Cast Large-Area Planar Perovskite Solar Cells/Modules Having Controlled Chloride Incorporation

Organic-inorganic perovskite photovoltaics are an emerging solar technology. Developing materials and processing techniques that can be implemented in large-scale manufacturing is extremely important for realizing the potential of commercialization. Here we report a hot-casting process with controlled Cl- incorporation which enables high stability and high power-conversion-efficiencies (PCEs) of 18.2% for small area (0.09 cm(2)) and 15.4% for large-area (approximate to 1 cm(2)) single solar cells. The enhanced performance versus tri-iodide perovskites can be ascribed to longer carrier diffusion lengths, improved uniformity of the perovskite film morphology, favorable perovskite crystallite orientation, a halide concentration gradient in the perovskite film, and reduced recombination by introducing Cl-. Additionally, Cl- improves the device stability by passivating the reaction between I- and the silver electrode. High-quality thin films deployed over a large-area 5 cm x 5 cm eight-cell module have been fabricated and exhibit an active-area PCE of 12.0%. The feasibility of material and processing strategies in industrial large-scale coating techniques is then shown by demonstrating a dip-coating process which shows promise for large throughput production of perovskite solar modules.