Effect of Jahn–Teller Distortion on the Carrier Migration in Cu-Doped TiO₂ Nanoarray for Enhanced Photoelectrochemical Water Oxidation

In this work, TiO2 nanoarray photoanodes with Cu2+ incorporation inside the lattice were synthesized by a facile hydrothermal method to improve its low utilization efficiency of the photogenenrated carrier limited by rapid charge recombination. With the effect of Jahn–Teller distortion, greater optimization of material geometry and electronic sturctures was achieved, which helped to realize better photoelectrochemical performance in the netural Na2SO4 solution for water oxidation. Density functional theory calculations also confirm the charge accumulation within the lattice of Cu-doped TiO2, meaning more efficient seperation and migration of the photogenerated electron–hole pairs. Meanwhile, with field-induced surface photovoltage spectroscopy analysis, the role of defect levels played in the electron–hole pair microdynamics can be understood, which manifest the behavior of carriers with its electron-trapped effect. Therefore, this work will offer a novel insight into achieving highly photoelectrochemical efficiency for oxygen evolution reaction by affecting electron–hole separation and migration at the atomic level.