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.