Method for producing organic light-emitting element, organic display panel, organic light-emitting device, method for forming functional layer, ink, substrate, organic light-emitting element, organic display device, and inkjet device

1. A method of manufacturing an organic light-emitting element, comprising:

preparing ink including functional material as a material for a functional layer and a solvent dissolving the functional material, and filling an inkjet device having an ink ejection nozzle with the ink, the functional material having a weight-average molecular weight greater than zero and equal to or less than 100,000;

preparing a substrate having a base layer including a first electrode;

positioning the inkjet device above the substrate, and causing the inkjet device to eject a drop of the ink onto the base layer of the substrate;

forming the functional layer by drying the ink ejected onto the base layer of the substrate; and

forming a second electrode above the functional layer, wherein

in the preparation of the ink, when a value Z denotes a reciprocal of the Ohnesorge number Oh determined by density ρ (g/m 3 ), surface tension γ (nM·m), and viscosity η (mPa·s) of the ink and a diameter r (mm) of the ink ejection nozzle, the value Z is within a range of Formula 1,

in the ejection of the drop of the ink, speed V (m/s) of the ejected drop of the ink is within a range of Formula 2, and

the value Z and the speed V (m/s) satisfy Formula 3:

0.7≦ Z≦ 13

where Z= 1/Ohnesorge number Oh= ( r· ρ·γ) 1/2 /η  (Formula 1);

3 ≦V≦ 6  (Formula 2); and

V≦− 2.17 Ln( Z )+8.47  (Formula 3).

2. The method of manufacturing the organic light-emitting element of claim 1 , wherein

the value Z is two or more and is ten or less, and

the speed V is 3 m/s or more and is 5 m/s or less.

3. The method of manufacturing the organic light-emitting element of claim 1 , wherein

the density ρ of the ink is more than 827 g/m 3 and is 1190 g/m 3 or less,

the surface tension γ of the ink is more than 27.3 mN·m and is 41.9 mN·m or less,

the viscosity η of the ink is more than 2.4 mPa·s and is 35.0 mPa·s or less, and

the diameter r of the ink ejection nozzle is 0.02 mm or more and is 0.03 mm or less.

4. The method of manufacturing the organic light-emitting element of claim 1 , wherein

in the preparation of the substrate, the substrate has a plurality of openings corresponding to respective pixel units and includes a plurality of banks each formed above the base layer to partition adjacent pixel units, and

in the ejection of the drop of the ink, drops of the ink are ejected onto the base layer in regions corresponding to the openings between the banks.

5. An organic display panel utilizing the organic light-emitting element manufactured by the method of claim 1 .

6. An organic light-emitting device utilizing the organic light-emitting element manufactured by the method of claim 1 .

7. An organic display device utilizing the organic light-emitting element manufactured by the method of claim 1 .

8. A method of forming a functional layer, comprising:

preparing ink including functional material as a material for the functional layer and a solvent dissolving the functional material, and filling an inkjet device having an ink ejection nozzle with the ink, the functional material having a weight-average molecular weight greater than zero and equal to or less than 100,000;

preparing a substrate on which the functional layer is to be formed;

positioning the inkjet device above the substrate, and causing the inkjet device to eject a drop of the ink onto the substrate; and

forming the functional layer by drying the ink ejected onto the substrate; and, wherein

in the preparation of the ink, when a value Z denotes a reciprocal of the Ohnesorge number Oh determined by density ρ (g/m 3 ), surface tension γ (mN·m), and viscosity η (mPa·s) of the ink and a diameter r (mm) of the ink ejection nozzle, the value Z is within a range of Formula 1,

in the ejection of the drop of the ink, speed V (m/s) of the ejected drop of the ink is within a range of Formula 2, and

the value Z and the speed V (m/s) satisfy Formula 3:

0.7≦ Z≦ 13

where Z= 1/Ohnesorge number Oh= ( r· ρ·γ) 1/2 /η  (Formula 1);

3 ≦V≦ 6  (Formula 2); and

V≦− 2.17 Ln( Z )+8.47  (Formula 3).

9. The method of forming the functional layer of claim 8 , wherein

the value Z is two or more and is ten or less, and

the speed V is 3 m/s or more and is 5 m/s or less.

10. The method of forming the functional layer of claim 8 , wherein

the density ρ of the ink is more than 827 g/m 3 and is 1190 g/m 3 or less,

the surface tension γ of the ink is more than 27.3 mN·m and is 41.9 mN·m or less,

the viscosity η of the ink is more than 2.4 mPa·s and is 35.0 mPa·s or less, and

the diameter r of the ink ejection nozzle is 0.02 mm or more and is 0.03 mm or less.

11. An ink that is ejected onto a substrate by an inkjet device having an ink ejection nozzle, and is dried to form a functional layer, comprising:

functional material as a material for the functional layer, the functional material having a weight-average molecular weight greater than zero and equal to or less than 100,000; and

a solvent dissolving the functional material, wherein

when a value Z denotes a reciprocal of the Ohnesorge number Oh determined by density ρ (g/m 3 ), surface tension γ (mN·m), and viscosity η (mPa·s) of the ink and a diameter r (mm) of the ink ejection nozzle, the value Z is within a range of Formula 1,

speed V (m/s) at which the ink is ejected is within a range of Formula 2, and

the value Z and the speed V (m/s) satisfy Formula 3:

0.7≦ Z≦ 13

where Z= 1/Ohnesorge number Oh= ( r· ρ·γ) 1/2 /η  (Formula 1);

3 ≦V≦ 6  (Formula 2); and

V≦− 2.17 Ln( Z )+8.47  (Formula 3).

12. The ink of claim 11 ,

including the solvent and the functional material as a material for the functional layer of an organic light-emitting element; and

being ejected onto a base layer of the substrate for the organic light-emitting element and dried to form the functional layer between a first electrode included in the base layer and a second electrode opposing the base layer.

13. The ink of claim 11 , wherein

when the speed V is 3 m/s or more and is 5 m/s or less, the value Z, which is determined by the density ρ (g/m 3 ), the surface tension γ (mN·m), and the viscosity η (mPa·s) of the ink, is two or more and is ten or less.

14. The ink of claim 11 , wherein

when the diameter r of the ink ejection nozzle is 0.02 mm or more and is 0.03 mm or less

the density ρ of the ink is more than 827 g/m 3 and is 1190 g/m 3 or less,

the surface tension γ of the ink is more than 27.3 mN·m and is 41.9 mN·m or less, and

the viscosity η of the ink is more than 2.4 mPa·s and is 35.0 mPa·s or less.

15. A substrate having the functional layer manufactured by using the ink of claim 11 .

16. The organic light-emitting element having the functional layer manufactured by using the ink of claim 12 .

17. An organic display panel including the organic light-emitting element having the functional layer manufactured by using the ink of claim 12 .

18. An organic light-emitting device including the organic light-emitting element having the functional layer manufactured by using the ink of claim 12 .

19. An organic display device including the organic light-emitting element having the functional layer manufactured by using the ink of claim 12 .

20. An inkjet device that is for containing therein ink including functional material as a material for a functional layer and a solvent dissolving the functional material, and ejects the ink from an ink ejection nozzle onto a substrate to form the functional layer, the functional material having a weight-average molecular weight greater than zero and equal to or less than 100,000, wherein

when a value Z denotes a reciprocal of the Ohnesorge number Oh determined by density ρ (g/m 3 ), surface tension γ (mN·m), and viscosity η (mPa·s) of the ink and a diameter r (mm) of the ink ejection nozzle, the value Z is within a range of Formula 1,

speed V (m/s) at which the ink is ejected is within a range of Formula 2, and

the value Z and the speed V (m/s) satisfy Formula 3:

0.7≦ Z≦ 13

where Z= 1/Ohnesorge number Oh= ( r· ρ·γ) 1/2 /η  (Formula 1);

3 ≦V≦ 6  (Formula 2); and

V≦− 2.17 Ln( Z )+8.47  (Formula 3).

21. The inkjet device of claim 20 , wherein

the functional material included in the ink is a material for the functional layer of an organic light-emitting element, and

the ink is ejected onto a base layer of the substrate for the organic light-emitting element to form the functional layer between a first electrode included in the base layer and a second electrode opposing the base layer.

22. A substrate having the functional layer manufactured by using the inkjet device of claim 20 .

23. The organic light-emitting element having the functional layer manufactured by using the inkjet device of claim 21 .

24. An organic display panel including the organic light-emitting element having the functional layer manufactured by using the inkjet device of claim 21 .

25. An organic light-emitting device including the organic light-emitting element having the functional layer manufactured by using the inkjet device of claim 21 .

26. An organic display device including the organic light-emitting element having the functional layer manufactured by using the inkjet device of claim 21 .