Density Functional Evaluation of Catechol Adsorption on Pristine and Reduced TiO₂(B)(100) Ultrathin Sheets for Dye-Sensitized Solar Cell Applications

Abstract

The introduction of defects is one of the most recurrent pathways to generate modifications to materials' electronic structure and surface reactivity. In this work, calculations based on the density functional theory (DFT) were applied to study the electronic properties of pristine and reduced TiO 2 (B)(100) ultrathin sheets to evaluate their potential as a semiconductor material for dye-sensitized solar cells (DSSCs). It was carried out by introducing vacancy defects on these surfaces and then adsorbing a catechol molecule, used as a model of a direct electron injection sensitizer (type-II dye), in different interaction configurations. Geometric, energetic, and electronic analyses were performed, focusing on the electronic structure changes and charge transfer between the dye and surface during molecular adsorption. The obtained results seem to indicate that a thickness of four layers is adequate to obtain a satisfactory slab model approximation of the TiO 2 (B)(100) surface. The presence of oxygen vacancy states among the majority of the reduced surfaces was observed as well as a reduction of the band gap energy value. Additionally, the adsorption of catechol in the reduced surface induced an increase in light absorption compared to the pristine model. These attributes suggest that reduced ultrathin sheets of TiO 2 (B) could be a suitable candidate as a photoelectrode for DSSC applications.

Fabrication of Catechol Sensitized Hollow Microspheres ZnTiO3/TiO2/ZnO for the Photodegradation of Methylene Blue

“…This spontaneous deprotonation of catechol differs from the predicted water‐assisted process and plays a key role in the conversion of catechol from electron acceptor to electron donor relative to the ZnO surface [17] . Heffner et al [18] . studied the electronic and optical properties of carbon‐doped TiO 2 (100) ultra‐thin surfaces using density functional theory calculations to evaluate their potential as photoelectrodes for dye‐sensitized solar cells.…”