Organic light-emitting device

摘要

The present invention relates to an organic light-emitting device which provides an electroluminescence (EL) or photoluminescence (PL) device with high external quantum efficiency. The present invention forms a composite film layer with continuously changing refraction indices between an ITO transparent electrode and a substrate made of plastic or glass. The refraction index of the composite film layer is the same as the ITO electrode at the interface with the ITO electrode. It decreases along the direction perpendicular to the substrate in a linear or nonlinear way. The refraction index is the same as that of the plastic or glass at the interface with the substrate. This way can avoid reflection due to the difference in the refraction index across the interface. The excited light originally trapped in the ITO electrode can be guided outwards. A preferred mean is to incorporate a photon wave guide formed at the interface between the substrate and the air to increase the external quantum efficiency of this type of organic light-emitting devices.