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.