Computationally-derived design rules for organic crystalline materials for photocatalytic water splitting

James Green^a

^aDepartment of Chemistry, Molecular Sciences Research Hub, Imperial College London, London, W12 0BZ, UK

Proceedings of MATSUS Spring 2026 Conference (MATSUSSpring26)

I4 Digital Discovery: From Energy Materials to Devices

Barcelona, Spain, 2026 March 23rd - 27th

Organizers: Shoichi Matsuda and Magda Titirici

Oral, James Green, presentation 402
Publication date: 15th December 2025

Organic crystalline materials are potential candidates for photocatalytic overall water splitting (OWS) which is of significant industrial importance for the production of green hydrogen for use as a fuel or chemical feedstock.^1–3 Extended metal-free crystalline materials such as covalent organic frameworks and graphitic carbon nitrides have been heavily investigated for OWS, where the latter, denser materials exhibit significantly higher hydrogen evolution rates than more porous COFs.^1,4 While organic crystals of single molecules have been heavily investigated for organic electronic applications such as OLEDs and solar cells, there has been comparatively much less research into OWS in these materials.^5,6 Organic molecular crystals are a promising platform due to their chemical diversity and large range of crystal structures and densities.³ The key question for the design of OWS photocatalysts is to what extent do chemical groups, extended vs molecular structures, crystal packing and density affect the electronic properties? Optical absorption, charge-transport properties, ionisation energy/electron affinity and dispersibility in water are key considerations and are influenced both by molecular properties and crystal structure, making computational modelling challenging.^7–9 In this work we shed light on these structure-property relationships by firstly investigating a series of widely known organic electronic materials including molecular crystals and COFs which have published crystal structures, using periodic Density Functional Theory (with the HSE06 functional). Here we analyse the effects of the above structural features on the calculated electronic properties such as band gap, band alignments, optical absorption and charge transport. We then devise a series of both molecular and bulk property descriptors and computationally screen organic materials from crystallographic databases based on these descriptors to highlight new potential OWS candidates.

References:

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