Single-Nanoparticle Collision Events: Tunneling Electron Transfer on a Titanium Dioxide Passivated n-Silicon Electrode

Single-nanoparticle collisions were observed on an n-type silicon electrode (600 μm diameter) passivated by a thin layer of amorphous TiO₂, where the current steps occurred by tunneling electron transfer. The observed collision frequency was in reasonable agreement with that predicted from theory. The isolated electrode, after a collision experiment, with a Pt/TiO₂/n-Si architecture was shown to retain the photoelectrochemical properties of n-Si without photocorrosion or current decay. The Pt/TiO₂/n-Si electrode produced 19 mA cm^-2 of photocurrent density under 100 mW cm^-2 irradiation from a xenon lamp during oxygen evolution without current fading for over 12 h.