Monolithic Series-Interconnected Two-Terminal Perovskite-CIGSe Tandem Solar Cells: Voltage-Matched or Current-Matched?

Perovskite-CIGSe tandem solar cells represent a promising path toward high-efficiency and low-cost photovoltaics. Typically, tandem solar cells are designed in a two-terminal current-matched (2T-CM) configuration. However, this design suffers from limitations related to spectral variations, which can lead to current mismatch and reduced energy yield. An alternative is the four-terminal (4T) configuration, where top and bottom cells operate independently, but this increases system complexity and cost. The two-terminal voltage-matched (2T-VM) configuration overcomes these challenges by matching the voltages of the top- and bottom cells, making 2T-VM tandems less sensitive to current mismatch while maintaining a simpler system design. This study explores the potential of monolithically interconnected 2T-VM perovskite-CIGSe tandems, focusing on laser patterning techniques for interconnecting the layers. A specific and promising interconnection approach is presented, and the necessary process steps are analyzed to evaluate how they can be adapted from well-established laser patterning techniques. Our findings indicate that the 2T-VM configuration offers a robust and cost-effective solution for achieving high energy yields with minimal complexity, positioning it as a viable alternative for next-generation thin-film solar technologies.