An organic light emitting diode device including an anode, a cathode facing the anode, and a light emitting member between the anode and cathode, wherein the light emitting member includes at least two light emitting units displaying the same or different color as one another, and a charge-generation layer between the at least two light emitting units, the charge-generation layer including a first charge-generation layer and a second charge-generation layer that each include an undoped material, and wherein the first charge-generation layer has an ionization energy that is about the same as or less than an electron affinity of the second charge-generation layer.