Chemisorption of a thiol-functionalized ruthenium dye on zinc oxide nanoparticles: Implications for dye-sensitized solar cells

► Ruthenium dyes may be adsorbed onto zinc oxide nanoparticles via the formation of Zn-S bonds. ► The surface density of the adsorbed dyes is similar to alkanethiols self-assembled on Au(1 1 1) surfaces. ► The energy level diagram, for the particular bipyridyl dye studied, indicates that its LUMO is slightly lower in energy than the zinc oxide conduction band edge. This is not optimal for charge transfer. ► Future design of thiol-functionalized Ru dyes could result in photovoltaic devices that compete favorably with titanium dioxide-based ones.