Ethanolic ZnO dispersions have been characterized by optical absorption spectroscopy, transmission electron microscopy, and X-ray diffraction spectroscopy. Freshly prepared dispersions contain spherical crystallites (hexagonal wurtzite), having an average diameter of 2 nm, and show confinement effects. Dispersions aged at room temperature for 5 days contain spherical crystallites, having an average diameter of 13 nm, and show no confinement effects. Transparent nanocrystalline films (thickness 4 μm) were formed on a conducting glass (SnO 2 ) substrate by sintering 13-nm crystallites in air at 450 o C for 3 h. Incorporation in an electrochemical cell, as the working electrode, permits potentiostatic control of the Fermi level within these films