Inorganic buffer structure for organic light-emitting diode devices

An OLED device, including a substrate, an anode formed of a conductive material over the substrate, an emissive layer having an electroluminescent material provided over the anode layer, a buffer structure including at least two layers, a first buffer layer provided over the electron-transport layer and containing an alkaline halide and a second buffer layer provided over the first buffer layer and containing a metal or metal alloy and having a work function of between 2.0 to 4.0 V; and a sputtered layer of a metal or metal alloy provided over the buffer structure.