Electrochemical Doping of Compact TiO2Thin Layers

Electrochemical n-doping of dense thin films of TiO 2 (anatase) occurs upon proton insertion from acidic aqueous electrolyte solution. Details of the reaction are investigated by cyclic voltammetry and by electrochemical impedance spectroscopy. The good-quality films are ideally compact, mimicking the properties of a macroscopic single-crystal electrode. The n-doping is stable for at least weeks of electrode storage in air at room temperature. Doping manifests itself by characteristic morphological differences of the surface. Electrochemical Li + insertion indicates that there is a competition between Li + and H + ions in the lattice, detectable by cyclic voltammetry.