Towards 3-Terminal Perovskite/Silicon Tandem Solar Cells: Influence of Silicon Bottom Cell on Tandem Cell Fabrication

bottom solar cells featuring an interdigitated back contact (IBC) based on laser processes can be integrated in highly efficient 3-Terminal perovskite/silicon tandem solar cells. While surface texturing of the Si bottom cell on the front side is essential for light trapping and thus enhanced absorption of long-wavelength light, it can hamper the conformal wet-chemical deposition of the perovskite top cell. Modification of our texture-etch allows a reduction of the pyramids size without affecting the light absorption in the Si cell. Our laser-processed double-side textured Si IBC cells reach efficiencies up to 22.6% under 1-sun illumination when using a non-optimized laser doping process. Perovskite layers deposited on these modified bottom cells cover their pyramids, which is necessary for shunt-free tandem devices. Since tandem operation requires a low-resistive electrical connection of the subcells, passivation properties of wet-processed SnO2 and TiO2 layers on Si are evaluated. To achieve higher tandem cell efficiencies, IBC solar cells with suitable passivating front contact layers need to be developed.