Ink for organic electroluminescent device, manufacturing method of organic electroluminescent device, organic display panel, organic display apparatus, organic electroluminescent apparatus, ink, forming method of functional layer, and organic electroluminescent device

1. An ink for an organic electroluminescent device, comprising:

a functional material for forming a functional layer of the organic electroluminescent device;

a first solvent for dissolving the functional material;

a second solvent that has a diester backbone and a second boiling point that is one of at most equal to a first boiling point of the first solvent or greater than the first boiling point of the first solvent by at most 20° C.; and

a third solvent that is an aliphatic alcohol and has a third boiling point that is less than the first boiling point of the first solvent and less than the second boiling point of the second solvent.

2. The ink for the organic electroluminescent device of claim 1 , wherein the ink is configured to transition, in an atmospheric environment, from a first state that includes the first solvent, the second solvent, and the third solvent to a second state that includes the first solvent and the second solvent in response to the third solvent evaporating, and from the second state to a third state that includes the first solvent in response to the second solvent evaporating.

3. The ink for the organic electroluminescent device of claim 1 , wherein a viscosity of the ink in a state that includes the first solvent, the second solvent, and the third solvent is at least approximately 3 mPa·s and at most approximately 20 mPa·s.

4. The ink for the organic electroluminescent device of claim 3 , wherein a viscosity of the ink in a state that includes the first solvent, the second solvent, and the third solvent is at least approximately 3 mPa·s and at most approximately 13 mPa·s.

5. The ink for the organic electroluminescent device of claim 1 , wherein a viscosity of the ink in a state that includes the first solvent and the second solvent after the third solvent evaporates is at least approximately 20 mPa·s and at most approximately 200 mPa·s.

6. The ink for the organic electroluminescent device of claim 5 , wherein a viscosity of the ink in a state that includes the first solvent and the second solvent after the third solvent evaporates is at least approximately 30 mPa·s and at most approximately 200 mPa·s.

7. The ink for the organic electroluminescent device of claim 1 , wherein a mixture ratio of the second solvent to a sum of the second solvent and the third solvent is at least approximately 30 mol % and at most approximately 70 mol %.

8. The ink for the organic electroluminescent device of claim 1 , wherein a mixture ratio of a first sum of the second solvent and the third solvent to a second sum of the first solvent, the second solvent, and the third solvent is at least approximately 3 mol % and at most approximately 20 mol %.

9. The ink for the organic electroluminescent device of claim 1 , wherein the first solvent is phenoxy toluene, the second solvent is dimethyl phthalate, the third solvent is 1-nonanole, and the functional material is F8-F6.

10. The ink for the organic electroluminescent device of claim 1 , wherein the first boiling point of the first solvent is at least approximately 260° C. and at most approximately 350° C., the second boiling point of the second solvent is at least approximately 280° C. and at most approximately 350° C., and the third boiling point of the third solvent is at least approximately 80° C. and at most approximately 250° C.

11. The ink for the organic electroluminescent device of claim 1 , wherein a concentration of the functional material is at least approximately 0.1 wt % and less than approximately 4 wt %.