Electrochemical behaviors of TiO2−x films synthesized by plasma-based ion implantation and deposition in fibrinogen containing PBS solution

TiO2−x films were synthesized on carbon by plasma-based ion implantation and deposition (PBII-D). Electrochemical behaviors of the prepared films were investigated in phosphate buffer solution (PBS) and fibrinogen containing PBS solution (PBS(Fn)), to probe charge transfer phenomena between TiO2−x film and fibrinogen. Electrochemical impedance spectroscopy (EIS) as well as simulated values of equivalent circuit units including reaction resistance and electric double layer has been obtained, indicating different charge transfer rate occurred across the interfaces. The shape of Mott-Schottky spectroscopy around the rest-open potential indicates that TiO2−x films are typical n-type semiconductor. Donor density results calculated by Mott-Schottky theory show that TiO2−x films exhibit higher donor density in PBS(Fn) than in PBS, indicating charge transfer from fibrinogen to TiO2−x films, and the space charge layers bend lower.