Spectral shape changes the optimal perovskite thickness of the 2-terminal perovskite/silicon tandem solar cell

In this work, we simulate and analyze the impact of spectral shape on the 2-terminal perovskite/silicon heterojunction tandem solar cell performance. Under the standard test condition (spectrum AM1. $\boldsymbol{5}\mathbf{G}\ {100}\ \mathbf{mW}/\mathbf{m}^{2}$, 300K), the optimal perovskite thickness of the 2-terminal tandem solar cell to maximize the tandem efficiency is 640 nm. However, we found that this optimal value depends significantly on the actual spectral shape. Specifically, the optimal perovskite thickness obtained is thinner than 640 nm under the blue-rich spectrum while thicker than 640 under the red-rich spectrum. This finding helps design suitable tandem structures in different climatic zones.