Highly passivated TOPCon bottom cells for perovskite/silicon tandem solar cells
Zetao Ding, Chenxia Kan, Shengguo Jiang, Meili Zhang, Hongyu Zhang, Wei Liu, Mingdun Liao, Zhenhai Yang, Pengjie Hang, Yuheng Zeng, Xuegong Yu, Jichun Ye
Abstract
Tunnel oxide passivated contact (TOPCon) silicon solar cells are rising as a competitive photovoltaic technology, seamlessly blending high efficiency with cost-effectiveness and mass production capabilities. However, the numerous defects from the fragile silicon oxide/c-Si interface and the low field-effect passivation due to the inadequate boron in-diffusion in p-type polycrystalline silicon (poly-Si) passivated contact reduce their open-circuit voltages (VOCs), impeding their widespread application in the promising perovskite/silicon tandem solar cells (TSCs) that hold a potential to break 30% module efficiency. To address this, we have developed a highly passivated p-type TOPCon structure by optimizing the oxidation conditions, boron in-diffusion, and aluminium oxide hydrogenation, thus pronouncedly improving the implied VOC (iVOC) of symmetric samples with p-type TOPCon structures on both sides to 715 mV and the VOC of completed double-sided TOPCon bottom cells to 710 mV. Consequently, integrating with perovskite top cells, our proof of concept of 1 cm2 n-i-p perovskite/silicon TSCs exhibit VOCs exceeding 1.9 V and a high efficiency of 28.20% (certified 27.3%), which paves a way for TOPCon cells in the commercialization of future tandems. Perovskite/silicon tandem solar cells have attracted great attention for their efficiency and industry-compatible fabrication. Here, authors report a p-type tunnel oxide passivated contact structure with improved implied open-circuit voltage, achieving efficiency over 28% in 1 cm2 n-i-p tandem cells.