Providing an emission-protecting layer in an oled device

An organic light-emitting device with improved performance including an anode formed over a substrate; a hole-transporting layer formed over the anode; and a light-emitting layer formed over the hole-transporting layer for producing light in response to hole-electron recombination. The organic light-emitting device also includes an emission-protecting layer formed over the light-emitting layer, wherein the emission-protecting layer includes one or more materials selected to resist the surface contamination on the organic light-emitting layer and to ensure that there will be less surface contamination than if such layer had not been provided; an electron-transporting layer formed over the emission-protecting layer; and a cathode formed over the electron-transporting layer.