The organic electroluminescence (EL) device using an organic material has been considered to be hopeful for use as a solid emitting type full color display device, which is cheap and has a large area and accordingly, there have widely been conducted a variety of investigations for the development of such devices. In general, the EL device comprises an emitting layer and a pair of electrodes sandwiching the emitting layer between them. The emission of light from the EL device is such a phenomenon that, when an electric field is applied between these electrodes, electrons are injected into the emitting layer from the side of the cathode, while holes are likewise injected into the layer from the side of the anode, subsequently the electrons are recombined with the holes within the emitting layer to generate excited states and energies are converted in the form of light to be emitted when the excited states are brought back to the ground states.
Conventional organic EL devices have a high driving voltage, and have a large leakage current as well as low luminance and efficiency of light emission, as compared with inorganic light-emitting diodes. In addition, deterioration in the performances of the organic EL devices is rapid. For these reasons, the organic EL devices have not yet been put to practical use. Although the organic EL devices have been gradually improved in these days (see, for example, Patent Document 1 and Patent Document 2), there are still demands for devices having a lower driving voltage, a longer lifetime, and also a smaller leakage current.    Patent Document 1: Japanese Patent No. 3571977.    Patent Document 2: Japanese Patent No. 3614405.