DFT Study of Heteronuclear (TMFeO3)x Molecular Clusters (Where TM = Sc, Ti, Fe and x = 2, 4, 8) for Photocatalytic and Photovoltaic Applications

Abstract

The computational modeling of metal oxide clusters for photovoltaic application is carried out by using density functional theory. The structural and electronic properties of heteronuclear (TMFeO3)x molecular clusters (where x = 2, 4, 8 and TM = Sc, Ti, Fe) are investigated in detail. The physical parameters such as energy gap, formation energy, binding energy, and stability are determined. The computed values and trends in electronegativity (χ), chemical potential (μ), hardness (η) and softness (S), positions of highest occupied molecular orbitals (HOMO) and lowest unoccupied molecular orbitals (LUMO), and HOMO-LUMO gap with varying cluster sizes are discussed. The iso-surface plots with relaxed structure related to the frontier MOs are described to shed light on the charge transfer mechanism. In the entire series of the studied clusters, the computed gap of (Fe2O3)8 was found minimal and thus suitable for red light absorption, whereas (TiFeO3)2 exhibited a maximum gap which shows potential for blue light absorption. The clusters exhibiting different values of the gap are found suitable to absorb the solar radiation. HOMO and LUMO position with their energy differences in the clusters are found compatible for applications in photocatalytic and photovoltaic applications. The observed trend in the computed parameters points to the potential of the simulated materials for application in a TiO2-based semiconducting photoanode to harvest sunlight.