Combining Drift-Diffusion and Equivalent-Circuit Models for Efficient 3D Tandem Solar Cell Simulations

For upscaling silicon based tandem solar cells from small laboratory sizes to full size formats compatible with industrial production, two-dimensional (2-D) and 3-D effects like metal grid layout, perimeter design, and lateral inhomogeneities gain importance for tandem cell development. For understanding and quantifying such effects, 3-D tandem modeling is helpful, but the capabilities of existing solar cell simulation tools is limited in this respect. In this article, we describe a numerically efficient 3-D tandem modeling approach implemented in the solar cell simulation software Quokka3. It combines a 1-D equivalent-circuit (EQC) model of the top cell within the front side's boundary condition with either the quasi-neutral 3-D drift-diffusion model or an EQC model for the bottom cell's bulk carrier transport. This way the addition of a top cell to a single-junction silicon bottom cell model in Quokka3 adds little effort in terms of computational time and is thus compatible with large-area 3-D simulations up to full cell geometries. We showcase the usefulness of this approach by investigating various perimeter designs of small-area silicon-perovskite cells.

Automated summary

This article presents an efficient 3-D tandem modeling approach implemented in a solar cell simulation software, which helps in understanding and quantifying the influence of various effects on tandem cell development. The usefulness of this approach is demonstrated by investigating perimeter designs of small-area silicon-perovskite cells.