An organic light emitting diode includes an emitting material layer including first and second layers; a first electrode on a side of the emitting material layer; and a second electrode on the other side of the light emitting material layer and facing the first electrode, wherein the first layer includes a first compound, and the second layer includes a second compound, wherein the first compound has a difference, between a singlet energy and a triplet energy, less than 0.3 eV, and wherein the singlet energy of the first compound is greater than a singlet energy of the second compound.