First Principles Study on Structurally Resolved Titanium Dioxide Nanoparticles Functionalized by Organic Ligands

Abstract

Titanium dioxide nanoparticles representing those in dye-sensitized solar cell photoanodes are modeled by first principles calculations, employing a series of structurally resolved polyoxometalates functionalized with organic ligands via the phosphonate anchoring group as a modeling platform. Previous computational studies on titanium dioxide nanoparticles for dye-sensitized solar cells and water splitting systems are based on artificial cleaving of TiO₂ from bulk crystals, which introduces potential various human-made errors. This manuscript focuses on structurally resolved titanium dioxide nanoparticles determined from X-ray diffraction experiments with a 10⁻³ Å resolution and demonstrates that charge transfer occurs from the organic ligands and oxygen atoms to the core titanium atoms. Also, different TiO₂ nanoparticle geometries contribute to variation in the electronic and optical properties of the organic/TiO₂ nanocomposite system. This computational work on structurally resolved molecularly functionalized titanium dioxide introduces a new way to model the TiO₂ nanoparticle-based optoelectronic device, which eliminates the arbitrariness introduced during artificial cleaving and provides insights on the structure-property relationships of organic molecule-functionalized titanium dioxide nanoparticles for water splitting systems and dye-sensitized solar cells.