Optimizing Solar Cell Top Metal Contact Design Introduction

Among the many design criteria for solar cells, the design of the top metal contact impacts the cell efficiency. The areal density of the top contact modifies the magnitude of the cell output power significantly.

Solar cells suffer from optical losses. These limit the total number of photogenerated carriers. Add to that, carriers suffer from electronic (recombination) losses. Using numerical simulations these losses can be quantified and minimized.

Photogenerated carriers experience bulk resistivities as well as surface sheet resistivity before collection at the top contacts. The contact design aims to maximise carrier collection against internal resistance and metal shadowing. For complex metal designs there are no simple analytical solutions for the optimum contact areal density. In this article, 3D TCAD software is used to maximise the cell output power as a function of contact areal density.