Limiting efficiencies of solar energy conversion and photo-detection via internal emission of hot electrons and hot holes in gold

TL;DR

This study assesses the maximum efficiency of gold-based solar energy converters using internal photoemission, revealing limitations for hot electron collection but promising results for hot hole harvesting, especially in hybrid systems.

Contribution

It provides ab initio calculations of efficiency limits for Au-semiconductor Schottky junctions, highlighting the potential of hot hole collection over hot electron injection.

Findings

Full-spectrum hot electron efficiency below 4%.

Hot hole collection efficiency exceeds 10%.

Hybrid systems can enhance solar spectrum harvesting.

Abstract

We evaluate the limiting efficiency of full and partial solar spectrum harvesting via the process of internal photoemission in Au-semiconductor Schottky junctions. Our results based on the ab initio calculations of the electron density of states (e-DOS) reveal that the limiting efficiency of the full-spectrum Au converter based on hot electron injection is below 4%. This value is even lower than previously established limit based on the parabolic approximation of the Au electron energy bands. However, we predict limiting efficiency exceeding 10% for the hot holes collection through the Schottky junction between Au and p-type semiconductor. Furthermore, we demonstrate that such converters have more potential if used as a part of the hybrid system for harvesting high- and low-energy photons of the solar spectrum.