Efficiency Limit of Transition Metal Dichalcogenide Solar Cells

TL;DR

This paper determines the theoretical efficiency limits of multilayer TMD solar cells, showing they can reach up to 25% efficiency at minimal thickness, highlighting their potential for high-power applications.

Contribution

It extends the detailed balance method to include Auger and defect recombination, providing new efficiency limits for TMD solar cells based on measured optical properties.

Findings

Single-junction TMD solar cells can reach 25% efficiency at 50 nm thickness.

TMD materials are promising for high-specific-power photovoltaics.

Efficiency limits are established considering realistic recombination mechanisms.

Abstract

Transition metal dichalcogenides (TMDs) show great promise as absorber materials in high-specific-power (i.e. high-power-per-weight) solar cells, due to their high optical absorption, desirable band gaps, and self-passivated surfaces. However, the ultimate performance limits of TMD solar cells remain unknown today. Here, we establish the efficiency limits of multilayer MoS2, MoSe2, WS2, and WSe2 solar cells under AM 1.5 G illumination as a function of TMD film thickness and material quality. We use an extended version of the detailed balance method which includes Auger and defect-assisted Shockley-Reed-Hall recombination mechanisms in addition to radiative losses, calculated from measured optical absorption spectra. We demonstrate that single-junction solar cells with TMD films as thin as 50 nm could in practice achieve up to 25% power conversion efficiency with the currently available material quality, making them an excellent choice for high-specific-power photovoltaics.