An improved OLED structure that enhances both stability and luminance efficiency, includes a substrate; an anode and a cathode; a light-emitting layer disposed between the anode and cathode; and a hole-transporting structure disposed between the light-emitting layer and the anode including two or more sublayers; a first sublayer in contact with the light-emitting layer and including a first hole-transporting material and a first stabilizing dopant, and a second sublayer including a second hole-transporting material and a second stabilizing dopant, and a third dopant having a bandgap that is smaller than each of the bandgaps of the second hole-transporting material and the second stabilizing dopant, respectively.