Atomic structure and electronic properties of hydrogenated X (=C, Si, Ge, and Sn) doped TiO2: A theoretical perspective

Titanium dioxide (TiO2) and especially its polymorph, anatase, are widely used transition-metal oxides for renewable energy applications such as photocatalytic and photovoltaic devices due to their chemical stability and their electrochemical and photocatalytic properties. However, the wide energy bandgap of anatase limits its photocatalytic ability and electron transport properties. Doping with appropriate elements is an established way to control and tune the optical and electronic properties of anatase such as conductivity, transparency, and bandgap. Metal doping can improve anatase’s properties as an electron transport layer, whereas non-metal (anion) doping is widely used to improve its photocatalytic activity. Herein, we investigate the effect of carbon group dopants in conjunction with hydrogenation of TiO2 by applying density functional theory. We find that hydrogenation has a positive impact on the structural and electronic properties of TiO2, thus making it an appropriate candidate for energy harvesting devices.