WB crystals with oxidized surface as counter electrode in dye-sensitized solar cells

Tungsten boride (WB) crystals, whose surface tends to be oxidized when exposed to air, were demonstrated to have a comparable activity to platinum as counter electrode material in dye-sensitized solar cells. The synergistic effect of both catalytically active surface layer WO_x and electronically conductive internal WB is considered to be responsible for the high activity of the WB crystals.