An opto-electronic device, such as an OLED or organic solar cell, having an electrode structure for use as a cathode. The electrode structure includes an electrically conductive layer and an inorganic layer, wherein the inorganic layer is made of at least one oxide-based alkali or alkaline earth metal intercalation compound. The intercalation compound having the chemical formula of A.sub.x(M.sub.xO.sub.z), where x, y, z are positive integers greater than zero, A is an alkali metal or alkaline earth element, M is a metal, transitional metal or metallic alloy, and O is oxygen. Furthermore, a buffer layer made of alkali oxides or halides, or alkaline earth oxides or halides can be provided between the conductive layer and the inorganic layer.