Method for producing organic electroluminescence element
Provided is a method for producing an organic electroluminescence device which contains an anode, a cathode and an organic layer between the anode and the cathode where the organic layer contains a light-emitting layer and an adjacent layer adjacent to the light-emitting layer, the method including: applying to the adjacent layer a coating liquid prepared by dissolving or dispersing a light-emitting material and a host material in a solvent, and heating the coating liquid applied to the adjacent layer at a temperature higher than a melting temperature of the host material and higher than a boiling point of the solvent, to thereby form the light-emitting layer, wherein a difference as an absolute value between contact angle A (°) of the light-emitting layer with respect to pure water and contact angle B (°) of the adjacent layer with respect to pure water is 13 (°) or smaller.
1. A method for producing an organic electroluminescence device which contains an anode, a cathode and an organic layer between the anode and the cathode where the organic layer contains a light-emitting layer and an adjacent layer adjacent to the light-emitting layer, the method comprising:
applying to the adjacent layer a coating liquid prepared by dissolving or dispersing a light-emitting material and a host material in a solvent,
heating the coating liquid applied to the adjacent layer at a temperature equal to or above the boiling point of the solvent but lower than the melting temperature of the host material until the coating liquid dries, and
after the coating liquid has dried, subsequently heating the coated adjacent layer at a temperature higher than the melting temperature of the host material to thereby form the light-emitting layer,
wherein a difference as an absolute value between contact angle A (°) of the light-emitting layer with respect to pure water and contact angle B (°) of the adjacent layer with respect to pure water is 13 (°) or smaller, and
wherein the host material is a compound expressed by any one of the following Structural Formulas (1) to (4):
2. The method for producing an organic electroluminescence device according to claim 1 , wherein the light-emitting material has a molecular weight of 1,500 or lower and the host material has a molecular weight of 1,500 or lower.
3. The method for producing an organic electroluminescence device according to claim 1 , wherein the host material is a compound represented by the following General Formula (1) or (2):
where R represents a t-butyl group, a t-amyl group, a trimethylsilyl group, a triphenylsilyl group or a phenyl group, and R 1 to R 23 each represent a hydrogen atom, a C1-C5 alkyl group, a cyano group, a fluorine atom, a trifluoro group, a trimethylsilyl group, a triphenylsilyl group or a phenyl group,
where R represents a t-butyl group, a t-amyl group, a trimethylsilyl group, a triphenylsilyl group or a phenyl group, and R 1 to R 23 each represent a hydrogen atom, a C1-C5 alkyl group, a cyano group, a fluorine atom, a trifluoro group, a trimethylsilyl group, a triphenylsilyl group or a phenyl group.
4. The method for producing an organic electroluminescence device according to claim 1 , wherein the solvent contains at least one selected from the group consisting of aromatic hydrocarbons and ketones each having a boiling point of 100° C. or higher.
5. The method for producing an organic electroluminescence device according to claim 1 , wherein the temperature of the heating of the coated adjacent layer is higher than the melting temperature of the host material by 20° C. or higher.
6. The method for producing an organic electroluminescence device according to claim 1 , wherein the light-emitting layer has an Ra value of 5 nm or more before the host material melts and the light-emitting layer has an Ra value of 1 nm or less after the host material melts.