Platinum-Enhanced Electron Transfer and Surface Passivation through Ultrathin Film Aluminum Oxide (Al₂O₃) on Si(111)-CH₃ Photoelectrodes.

We report the preparation, stability, and utility of Si(111)-CH3 photoelectrodes protected with thin films of aluminum oxide (Al2O3) prepared by atomic layer deposition (ALD). The photoelectrodes have been characterized by X-ray photoelectron spectroscopy (XPS), photoelectrochemistry (Fc in MeCN, Fc-OH in H2O), electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV) simulation. XPS analysis of the growing Al2O3 layer affords both the thickness, and information regarding two-dimensional versus three-dimensional mode of growth.