Organic electroluminescent device

Abstract

In order to improve the light emission efficiency and the light emission life time of an organic electroluminescent device, the invention provides a method for improving the dispersibility of a light emitting material in the light emitting layer. The light emitting device comprises electrodes consisting of an anode and a cathode provided on a substrate, and an organic light emitting layer between the electrodes, wherein the organic light emitting layer includes a light emitting material and a dopant for improving the dispersibility thereof. As the dopant, there are employed a light emitting compound and a non-light emitting compound or a current enhancing material. In case of employing the light emitting compound, the composition corresponds to a case of utilizing plural light emitting materials, and, in such case, the light emission wavelengths are preferably mutually closer. Also evaporation of the light emitting material and the dopant in a same evaporation boat allows to reduce the evaporation temperature, to improve the dispersibility of the light emitting material and to improve the device characteristics. In this manner there can be obtained a light emitting device of a high light emission efficiency and a long light emission life.

Dependencies are inferred from the claim text.