A Computational Study of Organic Molecular Crystals for Photocatalytic Water Splitting

TL;DR

This study uses computational methods to evaluate organic crystalline materials for photocatalytic water splitting, comparing molecular and solid-state calculations to identify promising candidates efficiently.

Contribution

It demonstrates that gas-phase molecular calculations can effectively screen organic crystals for water splitting, reducing computational costs compared to periodic DFT.

Findings

Gas-phase molecular calculations agree well with experimental data.

Periodic DFT accurately predicts electronic properties of organic crystals.

Gas-phase screening can identify promising photocatalysts efficiently.

Abstract

Organic crystalline materials are potential candidates for photocatalytic overall water splitting (OWS). Although organic crystals have been heavily investigated for application in organic electronics, such as organic light-emitting diodes (OLEDs) and solar cells, there have been comparatively fewer studies into OWS in these materials. A major challenge is the large number of electronic and structural criteria that must be met for a material to make a viable OWS photocatalyst. Optical absorption, reduction and oxidation potentials and charge-transport properties are among the key considerations, and these are influenced both by molecular properties and the solid-state packing arrangement, making computational modelling challenging. Here, we investigate a series of known organic electronic materials that have published crystal structures using periodic density functional theory (DFT) and compare their calculated electronic properties of optical absorption and reduction and oxidation potentials with literature experimental data. Furthermore we perform a series of gas-phase molecular calculations which show a good agreement with literature data and periodic DFT for the optoelectronic properties of the organic molecular crystals studied, showing that gas-phase molecular calculations could be used to screen organic crystals for OWS at a reduced computational cost.