Abstract: An organic light-emitting device includes a positive electrode, a negative electrode and at least one organic material layer between the positive electrode and the negative electrode. The at least one organic material layer includes a hole-injecting layer, a hole-transporting layer, an emission layer, an electron-transporting layer, and an electron-injecting layer, and the emission layer includes a host material and a dopant material. In addition, a lifetime enhancement layer including a bipolar compound is positioned between the emission layer and the electron-transporting layer.