Nanophotonic Light Management for Perovskite-Silicon Tandem Solar Cells

TL;DR

This paper explores how nanophotonic sinusoidal nanotextures can significantly reduce reflective losses in perovskite-silicon tandem solar cells, boosting current utilization from 91% to 98% through numerical simulations and experimental investigations.

Contribution

It introduces the use of hexagonal sinusoidal nanotextures to enhance light management and reduce reflection in perovskite-silicon tandem solar cells, supported by simulations and initial experimental results.

Findings

Nanotextures increase current density utilization to 98%.

Reflection losses are minimized with sinusoidal nanotextures.

Experimental analysis of perovskite layer morphology on structured substrates.

Abstract

Perovskite-silicon tandem solar cells are currently one of the most investigated concepts to overcome the theoretical limit for the power conversion efficiency of silicon solar cells. For monolithic tandem solar cells the available light must be distributed equally between the two subcells, which is known as current matching. For a planar device design, a global optimization of the layer thicknesses in the perovskite top cell allows current matching to be reached and reflective losses of the solar cell to be minimized at the same time. However, even after this optimization reflection and parasitic absorption losses occur, which add up to 7 mA/cm$^2$. In this contribution we use numerical simulations to study, how well hexagonal sinusoidal nanotextures in the perovskite top-cell can reduce the reflective losses of the combined tandem device. We investigate three configurations. The current density utilization can be increased from 91% for the optimized planar reference to 98% for the best nanotextured device (period 500 nm and peak-to-valley height 500 nm), where 100% refers to the Tiedje-Yablonovitch limit. In a first attempt to experimentally realize such nanophotonically structured perovskite solar cells for monolithic tandems, we investigate the morphology of perovskite layers, which are deposited onto sinusoidally structured substrates.