Efficient Multiple Exciton Generation in Monolayer MoS2

TL;DR

This paper demonstrates highly efficient multiple exciton generation in monolayer MoS2, showing its potential for enhancing photovoltaic device efficiency through exciton multiplication at low energy thresholds.

Contribution

It provides the first experimental evidence of efficient MEG in monolayer MoS2 with low threshold energy and high efficiency, highlighting its potential for solar energy applications.

Findings

Achieved 86% MEG efficiency in monolayer MoS2.

Demonstrated low threshold energy for MEG.

Indicated vdW-layered materials as promising for flexible solar devices.

Abstract

Utilizing the excess energy of photoexcitation that is otherwise lost as thermal effects can improve the efficiency of next-generation light-harvesting devices. Multiple exciton generation (MEG) in semiconducting materials yields two or more excitons by absorbing a single high-energy photon, which can break the Shockley-Queisser limit for the conversion efficiency of photovoltaic devices. Recently, monolayer transition metal dichalcogenides (TMDs) have emerged as promising light-harvesting materials because of their high absorption coefficient. Here, we report efficient MEG with low threshold energy and high (86%) efficiency in a van der Waals (vdW) layered material, MoS2. Through different experimental approaches, we demonstrate the signature of exciton multiplication and discuss the possible origin of decisive MEG in monolayer MoS2. Our results reveal that vdW-layered materials could be a potential candidate for developing mechanically flexible and highly efficient next generation solar cells and photodetectors.