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First-Principles Modeling of a Dye-Sensitized TiO2/IrO2 Photoanode for Water Oxidation

Pastore, Mariachiara, De Angelis, Filippo
Journal of the American Chemical Society 2015 v.137 no.17 pp. 5798-5809
catalysts, electron transfer, models, nanoparticles, oxidation, quantitative analysis, semiconductors, solar energy, titanium dioxide
We present a first-principle computational modeling investigation, based on density functional theory (DFT) and time-dependent DFT, on the structural, electronic, optical, and charge generation properties of the semiconductor/dye/catalyst heterointerfaces in a prototypical dye-sensitized photoanode for water oxidation. The investigated architecture comprises a Ru(II) dye-sensitized TiO₂ substrate tethered to an IrO₂ nanoparticle catalyst. Our realistic modeling strategy and quantitative analysis of the relevant interfacial hole/electron transfer reactions indicates the slow hole injection into IrO₂ and the fast dye excited-state quenching to IrO₂ as the primary sources of the relatively poor cell efficiency experimentally observed. On the basis of this atomistic and electronic structure information, we propose and computationally test, against a prototype dye, a new class of Ru(II) sensitizers, which show potentially improved photoelectrochemical performances. This study constitutes a first step toward the computer-assisted design of new and more efficient materials for solar fuels production through dye-sensitized photoelectrochemical cells.