Modeling two and three-junction perovskite/silicon and perovskite/CIS tandem solar cells

Abstract Research on tandem solar cells that include perovskite (PVK) materials has seen a remarkable advance due to their potential high efficiency since the band gap of perovskite materials can be fine-tuned in a wide range. In this work, a theoretical model that can be applied to tandem solar cells with multiple perovskite junctions is discussed. Then, results for two-terminal solar cells consisting of two and three junctions, based on Silicon (Si) and CuInSe 2 (CIS), considering the PVK/Si, PVK/CIS, PVK/PVK/Si, and PVK/PVK/CIS designs are shown. The results show the efficiency limits as a function of the band gap for the perovskite junctions, reaching maximum efficiencies around 50% for the three-junction cells PVK/PVK/Si and PVK/PVK/CIS. In the more realistic case, where finite absorption by the perovskite materials is taken in account, the efficiency is estimated considering both the band gap and thickness of the perovskite junctions, while keeping the Si and CIS junctions thicknesses constant. In this case, it is shown that efficiencies greater than 42.5% can be achieved for two-junction solar cells (when the appropriate thickness and perovskite band gap are chosen). Similarly, the possible practical efficiency for the three-junction solar cells PVK/PVK/Si and PVK/PVK/CIS can be up to 47.5%. It can be concluded that tandem solar cells that combine perovskite cells with existing Si and CIS technologies can achieve higher efficiencies so that there is still room for improvements at the laboratory for current two-junction PVK/Si and PVK/CIS tandem solar cells.