An organic light-emitting device includes a substrate, an anode, a cathode, disposed between the anode and the cathode is an electroluminescent medium including, in sequence: a hole-transporting layer; an interface layer; a light-emitting layer; and an electron-transporting layer. The interface layer comprises a compound having an ionization potential greater than that of the organic compound of the hole-transporting layer, and an energy bandgap equal to or greater than that of the organic compound of the light-emitting layer. Wherein the thickness of the interface layer is in the range of 0.1 nm˜5 nm. The interface layer provides more balanced carrier recombination in the light-emitting layer, and achieves higher luminance efficiency.