Impact of Ga-V Codoping on Interfacial Electron Transfer in Dye-Sensitized TiO2.

The improvement of charge transfer between an organic molecule and a semiconductor is an important and challenging goal in the fields of photovoltaics and photocatalysis. In this work, we present a time-dependent density functional theory investigation of the impact of Ga-V codoping of TiO2 on the excited-state electron injection from perylene-3-carboxylic acid. The doping is shown to raise the charge-transfer efficiency for the highest possible surface dye uptake by ∼16%. The strength of the effect depends on the dopant-pair-dye separation, dopant concentration, and distribution of Ga, V atoms in TiO2. The doping of the superficial level turns out to be more favorable than those in the bulk. The changes in electron injection dynamics are attributed to the modification of accepting semiconductor levels and hybridization profile between molecular and semiconductor states.