Unveiling the Potential of Ultra-Thin Perovskite-Silicon Tandem Photovoltaics Boosted with Photonic Management

The merging of thin-film photovoltaic (PV) technologies with tandem architectures, such as perovskite-on-silicon double-junction solar cells, offers avenues to expand solar electricity. Their combination of flexibility, affordability, low weight, and high efficiency enables applications ranging from portable electronics to building-integrated and vehicle-integrated PV, or solar-powered space systems. Nevertheless, the efficiency of perovskite-on-silicon tandem PV is often constrained by suboptimal optical management, particularly in ultra-thin designs where light trapping (LT) and current/voltage matching are critical. Here, we develop an optoelectronic framework to optimize 2- and 4-terminal perovskite-silicon tandem cells, featuring 1 mu m-thick crystalline silicon absorbers with front-integrated photonic structures. To maximize power conversion efficiency (PCE), both the LT geometry and perovskite thickness were systematically optimized. In addition, indium tin oxide (ITO)-based and optically engineered interlayers are shown to exhibit similar optical performance, reinforcing ITO as a choice for 2-terminal tandems. The ultra-thin photonic-enhanced 2-terminal tandem achieves a PCE of 23.8%, corresponding to a 21.8% relative improvement over its planar counterpart, whereas the 4-terminal configuration reached a combined efficiency of 26.7%, primarily from LT-improved silicon photocurrent. These findings highlight the role of opto-electronically optimized light-management solutions in unlocking the potential of ultra-thin tandem solar cells for flexible, high-efficiency, and energy harvesting, paving the way for next-generation photovoltaics.