Low-Temperature Blade-Coated Perovskite Solar Cells

Spin coating has been the primary choice of deposition method used in the assembly of lab-scale perovskite solar cells. Other deposition methods are still lagging behind, both in terms of device efficiency and in the control of perovskite formation/morphology. Usually, improvements in these processes have been achieved with strategies that are not compatible with the industrial scale, either because of the use of hazardous solvents or due to the costly steps adopted. Here, we report the development of a route to prepare all layers of perovskite solar cells (except the electrodes) through the blade-coating technique, which is a scalable method and can be applied to produce large-area solar cells. We discuss how each process parameter affects the device performance and show that, by tuning the ink composition (i.e., solvent and lead precursors), it is possible to reduce the temperature of the deposition and achieve a perovskite layer with adequate grain size and good coverage of the substrate. With these modifications, a solar cell with a p-i-n configuration assembled in a dry air atmosphere with 15-20% humidity and using the blade coater at 50 degrees C delivered a maximum of 14.3% of efficiency.