High‐Efficiency Organic‐Dye‐ Sensitized Solar Cells Controlled by Nanocrystalline‐TiO 2 Electrode Thickness

A mesoscopic bilayer TiO2 film used as an electron collector in conjunction with an acetonitrile- or ionic liquid-based electrolyte greatly improves the performance of dye-sensitized solar cells (see figure). The thickness of the nanocrystalline TiO2 film affects the photovoltaic characteristics, particularly for the ionic-liquid-based electrolyte, owing to a limitation of the photocurrent by the diffusion of I3– ions.