Inkjet-Printed Compact TiO₂ Electron Transport Layer for Perovskite Solar Cells

Drop-on-demand inkjet printing is an easily upscalable, rapid, and digital deposition technique that allows thin film formation with a high material utilization rate as ideally needed for solar cell production. Herein, a method is reported to prepare inkjet-printed compact TiO₂ thin films that are further assessed as an electron transport layer (ETL) for perovskite solar cells and compared to reference dip-coated TiO₂ layers. Through ink formula engineering and adjustment of the printing parameters, reliable process control is achieved, leading to a homogeneous TiO₂ coating of the fluorine-doped tin oxide substrate. Perovskite solar cells with an inkjet-printed TiO₂ ETL yields efficiencies of up to 13.7%, outperforming the efficiency and the process repeatability of devices prepared with the dip-coated TiO₂ reference. Together with other recent contributions on inkjet-printed perovskite solar cells, this work contributes to highlight the processability of thin film solar cells using digital inkjet printing for next-generation photovoltaic applications.