A thin-film metal-oxide compound includes a titanium dioxide layer having a thickness of about 100 to 1000 nanometers. The titanium dioxide layer has a single-phase anatase structure. The titanium dioxide layer is directly disposed on a substrate comprised of glass, sapphire, or silicon. A solar cell includes a backing layer, a p-n junction layer, a metal-oxide layer, a top electrical layer and a contact layer. The backing layer includes a p-type semiconductor material. The p-n junction layer has a first side disposed on a front side of the backing layer. The metal-oxide layer includes an n-type titanium dioxide film having a thickness in the range of about 100 to about 1000 nanometers. The metal-oxide layer is disposed on a second side of the p-n junction layer. The top electrical layer is disposed on the metal-oxide layer, and the contact layer is disposed on a back side of the backing layer.