PHOSPHORESCENT ORGANIC ELECTROLUMINESCENT ELEMENT AND LIGHTING DEVICE

摘要

Provided is a white light-emitting organic electroluminescent element which comprises a plurality of phosphorescent dopants having different emission wavelengths and which has high efficiency, long service life and excellent chromaticity stability in terms of driving voltage and in terms of drive over time. This organic electroluminescent element is characterized in that: the element comprises a pair of electrodes on a substrate and two light-emitting layers arranged between the electrodes, each of said light-emitting layers containing a host material and a phosphorescent dopant; the host material of the two light-emitting layers are composed of different compounds; at least one of the phosphorescent dopants contained in the two light-emitting layers is a blue phosphorescent dopant having an ionization potential (Ip) of 5.3 eV or less; at least one of the two light-emitting layers contains a plurality of phosphorescent dopants; and the concentration of the blue phosphorescent dopant at least in the positive electrode-side light-emitting layer has a concentration gradient in the thickness direction of the light-emitting layer with a higher concentration on the positive electrode side.