Broadband Light Harvesting from Scalable Two-Dimensional Semiconductor Heterostructures

TL;DR

This paper demonstrates a scalable, planar semiconductor thin-film absorber using monolayer TMDCs that achieves broadband visible light absorption over 70%, offering a lightweight alternative to plasmonic structures for optoelectronic applications.

Contribution

It introduces a novel, unpatterned semiconductor thin-film absorber based on monolayer TMDCs with high broadband absorption and potential for high efficiency in photovoltaic devices.

Findings

Achieved >70% average absorption in 450-700 nm range

Demonstrated scalable vapor phase growth of TMDC films

Projected PCE of 15.54% and power >300 W g^-1 in photovoltaic applications

Abstract

Broadband absorption in the visible spectrum is essential in optoelectronic applications that involve power conversion such as photovoltaics and photocatalysis. Most ultrathin broadband absorbers use parasitic plasmonic structures that maximize absorption using surface plasmons and/or Fabry-Perot cavities, which limits the weight efficiency of the device. Here, we show the theoretical and experimental realization of an unpatterned/planar semiconductor thin-film absorber based on monolayer transition metal dichalcogenides (TMDCs). We experimentally demonstrate an average total absorption in the visible range (450 nm - 700 nm) of > 70% using > 4 nm of semiconductor absorbing materials scalable over large areas with vapor phase growth techniques. Our analysis suggests that a power conversion efficiency (PCE) of 15.54% and a specific power > 300 W g^-1 may be achieved in a photovoltaic cell based on this metamaterial absorber.