Performance estimation of a V-shaped perovskite/silicon tandem device: A case study based on a bifacial heterojunction silicon cell

Perovskite/silicon tandem solar cell is emerging as an efficient technology to surpass the single-junction solar cell limiting efficiency for advancing the process of carbon neutrality. The V-shaped perovskite/silicon tandem device is a promising strategy for efficient commercial photovoltaic utilization technology that requires only half usage amount of silicon cells comparing to other tandem architectures. However, the performance estimation method as well as the optimization pathway of the V-shaped tandem device are still unclear. Here we develop a method for performance estimation of the V-shaped tandem device, as well as for selection and optimization of the perovskite sub-cell by coupling a spectral efficiency calculation model and an optical simulation model of the perovskite solar cell. A fabricated 23%-efficient heterojunction silicon cell and an optical model of the perovskite solar cell with a typical n-i-p structure were employed for method demonstration. The effects of materials, bandgaps and thicknesses of layers in a perovskite solar cell on the tandem performance were calculated, and a factor f was introduced to establish a unified criterion for quantifying these effects, which provides a clear view of the trade-offs between various parameters in device optimization. Both ideal and non-ideal conditions are studied and discussed in this paper. It is found that the tin-doped indium oxide and spiro-OMeTAD are the two materials that had the most significant impact on the optical coupling between two sub-cells. By replacing or thinning these materials, the results point out a feasible way to exceed 30% efficiency for the V-shaped tandem device.