Organic EL device and preparation method

An organic EL device comprising, in order, a substrate, a first electrode on the substrate, two or more stacked organic layers on the first electrode including a light emitting layer, and a second electrode on the organic layers, wherein

• at least one layer of the two or more stacked organic layers other than the light emitting layer contains at least one high or low molecular weight compound selected from the group consisting of oxadiazole, triazole, thiadiazole, quinoline, quinoxaline, phenanthroline, and derivatives thereof,
• the light emitting layer contains a polymer which is a π-conjugated polymer, polyvinyl compound, polyacrylate, polymethacrylate or a derivative thereof, and
• the organic layers are formed by coating,
• wherein the at least one layer containing at least one high or low molecular weight compound is formed by coating a solution of the at least one high or low molecular weight compound in a solvent which is selected from the group consisting of (i) a chain compound of 3 to 6 carbon atoms in total, having on the molecule at least one alkoxy group of 1 to 3 carbon atoms, carbonyl group, or ester group of 2 to 3 carbon atoms, and a hydroxyl group at the α- and/or β-position thereto, (ii) a chain compound of 3 to 6 carbon atoms in total, having on the molecule a dialkylamide group of 2 to 4 carbon atoms, (iii) an ester form of chain compound having 5 to 8 carbon atoms in total, (iv) a carbonate form of chain compound having 4 to 7 carbon atoms in total, and (v) mixtures thereof.