Tuning Range-Separated Density Functional Theory for Photocatalytic Water Splitting Systems

TL;DR

This paper presents a system-specific optimization of range-separated DFT to accurately predict charge-transfer properties in photocatalytic water splitting systems involving Ir(III) photosensitizers, addressing medium effects and complex electronic interactions.

Contribution

It introduces a tailored optimization approach for range-separated DFT parameters to improve the description of charge-transfer states in photocatalytic systems, considering medium effects.

Findings

Optimized range-separation parameters improve charge-transfer state predictions.

Medium effects pose challenges for polarizable continuum models.

System-specific tuning enhances DFT accuracy for photocatalytic properties.

Abstract

We discuss the system-specific optimization of long-range separated density functional theory (DFT) for the prediction of electronic properties relevant for a photocatalytic cycle based on an Ir(III) photosensitizer (IrPS). Special attention is paid to the charge-transfer properties, which are of key importance for the photoexcitation dynamics, but and cannot be correctly described by means of conventional DFT. The optimization of the range-separation parameter using the $\Delta$SCF method is discussed for IrPS including its derivatives and complexes with electron donors and acceptors used in photocatalytic hydrogen production. Particular attention is paid to the problems arising for a description of medium effects by means of a polarizable continuum model.