Is Shunt Quenching Relevant to Minimize Shunt Losses in Perovskite–Silicon Tandem Solar Cells?

Abstract

One challenge in thin-film based solar cells, including perovskite-silicon tandem cells, is the defect-free deposition of the thin-film layers. Such defects can result in high local parasitic current losses, that is, local shunt spots. Depending on the nature of the defects, their geometrical distribution can either be microscopic, for example, induced by texture morphology, or macroscopic, for example, induced by particles during processing. Instead of avoiding the defects themselves, so-called shunt-quenching methods have been proposed to mitigate the associated efficiency loss. This work investigates the following recently suggested methods: 1) a deliberate current mismatch; and 2) engineering the resistive properties of the intermediate layers between the subcells to electrically isolate the shunt. A comprehensive 3D device simulation study is presented to quantitatively analyze the (in)effectiveness of these methods. It is found that shunt-quenching by a deliberate current mismatch can only play a minor role in the overall optimization of the current match point. Engineering the resistive properties of the intermediate layers must be generally considered ineffective. It only works for the rather specific case of strong and macroscopically distributed shunts with little cell-to-cell variation and only if some further requirements of the cell design are met.