The Future of Perovskite Photovoltaics-Thermal Evaporation or Solution Processing?

The last decade has seen remarkable advancements in the field of perovskite materials and photovoltaic technologies. One of their most extraordinary characteristics is the high quality of layers that can be obtained by dirty processing from solution at low temperatures. Alternatively, perovskites can also be deposited by thermal evaporation, a clean, solvent-free process, which is well established for many industrial applications. Although the vast majority of research reports focus on solution-processing as the deposition method for perovskite solar cells, thermally evaporated perovskite solar cells are closing in the performance gap with several reports of efficiencies above 20%. In this Progress Report, the two deposition methods are briefly introduced, the key developments in photovoltaic devices based on each deposition technique are outlined, and the challenges and future possibilities are discussed.