Excitonic Effects in Absorption Spectra of Carbon Dioxide Reduction Photocatalysts

TL;DR

This study investigates excitonic effects in nearly 50 photocatalysts for CO2 reduction using advanced computational methods, revealing a correlation between different models and proposing new screening criteria for material discovery.

Contribution

It introduces a novel approach to include excitonic effects in photocatalyst screening, utilizing Bethe-Salpeter formalism and correlating it with simpler models.

Findings

Strong correlation between Bethe-Salpeter and Wannier-Mott exciton binding energies.

Proposed three new optical screening criteria considering excitonic effects.

Reduced computational cost for excitonic property estimation in photocatalyst discovery.

Abstract

The formation and disassociation of excitons plays a crucial role in any photovoltaic or photocatalytic application. However, excitonic effects are seldom considered in materials discovery studies due to the monumental computational cost associated with the examination of these properties. Here, we study the excitonic properties of nearly 50 photocatalysts using state-of-the-art Bethe-Salpeter formalism. These $\sim$ 50 materials were recently recognized as promising photocatalysts for CO$_2$ reduction through a data-driven screening of 68,860 materials. Here, we propose three screening criteria based on the optical properties of these materials, taking excitonic effects into account, to further down select 6 materials. Remarkably we find a strong correlation between the exciton binding energies obtained from the Bethe-Salpeter formalism and those obtained from the computationally much less-expensive Wannier-Mott model for these chemically diverse $\sim$ 50 materials. This work presents a new paradigm towards the inclusion of excitonic effects in future materials discovery for solar-energy harvesting applications.