Method to make organic electroluminescent element material
In the present invention, provided is an organic electroluminescent element material having a high externally taking-out quantum efficiency, which is suitable for manufacturing an element exhibiting long light emission lifetime, and also provided is an organic electroluminescent element possessing the material, a method of manufacturing the organic electroluminescent element, and a display as well as an illuminating device fitted with the organic electroluminescent element.
1. A method of manufacturing an organic electroluminescent element comprising a substrate, a hole transport layer containing a polymer, and a light emission layer containing a phosphorescence dopant, the method comprising the steps of:
purifying a monomer with silica gel chromatography one or two times, followed by recrystallization two or three times to make a purified monomer having an impurity content of 1000 ppm or less;
synthesizing the polymer from at least the purified monomer having the impurity content of 1000 ppm or less via a halogen coupling reaction;
recovering the polymer;
forming the hole transport layer containing the polymer on the substrate by a wet coating process followed by a heating process; and
forming the light emission layer containing the phosphorescence dopant on the hole transport layer,
wherein the polymer comprises a partial structure represented by the following formula
—Ar1-N(Ar3)-Ar2-
wherein each of Ar1 and Ar2 independently represents an arylene group or a heteroarylene group, and Ar3 represents an aromatic hydrocarbon group or an aromatic heterocyclic group.
2. The method of manufacturing an organic electroluminescent element of claim 1 ,
wherein, in the step of purifying the monomer, the recrystallization is conducted three times.