Organic EL display unit, method of manufacturing the same, and solution used in method

1. An organic electroluminescence display unit comprising:

a respective lower electrode provided on a substrate for each of a first blue organic electroluminescence device and a second organic electroluminescence device of a color different from blue;

a respective first hole injection/transport layer provided on the lower electrode for each of the first blue organic electroluminescence device and the second organic electroluminescence device;

a respective organic light emitting layer of the color different from blue provided on the first hole injection/transport layer for the second organic electroluminescence device;

a second hole injection/transport layer made of a low molecular material, and provided on the entire surfaces of the organic light emitting layer of the color different from blue and the first hole injection/transport layer for the first blue organic electroluminescence device;

a blue organic light emitting layer provided on the entire surface of the second hole injection/transport layer; and

an electron injection/transport layer and an upper electrode that are provided in sequence on the entire surface of the blue organic light emitting layer.

2. The organic electroluminescence display unit of claim 1 , wherein the second organic electroluminescence device is at least one of a red organic electroluminescence device, a green organic electroluminescence device, and a yellow organic electroluminescence device.

3. The organic electroluminescence display unit of claim 2 , wherein the organic light emitting layer of the color different from blue includes a polymer material and a low molecular material, and a mixture ratio of the polymer material to the low molecular material is 10:1 to 1:2, both inclusive.

4. The organic electroluminescence display unit of claim 1 , wherein the blue organic light emitting layer includes a low molecular material.

5. The organic electroluminescence display unit of claim 1 , wherein

the first hole injection/transport layer comprises a hole injection layer and a hole transport layer formed on the hole injection layer,

the hole transport layer of the first blue organic electroluminescence device includes a low molecular material, and

the first hole injection/transport layer of the second organic electroluminescence device includes a polymer material.

6. The organic electroluminescence display unit of claim 1 , wherein

the first hole injection/transport layer comprises a hole injection layer and a hole transport layer formed on the hole injection layer,

the hole transport layer of the first blue organic electroluminescence device includes a polymer material, and

the first hole injection/transport layer of the second organic electroluminescence device includes a polymer material.

7. The organic electroluminescence display unit of claim 1 , wherein

the first hole injection/transport layer of the second organic electroluminescence device includes a polymer material, and

the first blue organic electroluminescence device is composed of only the hole injection layer.

8. The organic electroluminescence display unit of claim 3 , wherein the low molecular material is a compound expressed by Formula 1:

where A1 to A3 represent an aromatic hydrocarbon group, a heterocyclic group, or a derivative thereof.

9. The organic electroluminescence display unit of claim 3 , wherein the low molecular material is a compound expressed in Formula 2; however, excluding the compounds included in Formula 1:

where Z represents a nitrogen-containing hydrocarbon group or a derivative thereof; L1 represents a group in which one to four bivalent aromatic ring groups are bonded, and specifically, a bivalent group in which one to four aromatic rings are bonded, or a derivative thereof; A4 and A5 represent an aromatic hydrocarbon group, an aromatic heterocyclic group, or a derivative thereof; however, A4 and A5 may bond to each other and form a ring-shaped structure.

10. The organic electroluminescence display unit of claim 3 , wherein the low molecular material is a compound expressed in Formula 3; however, excluding the compounds included in Formula 1:

where L1 represents a group in which two to six bivalent aromatic ring groups are bonded, and specifically, a bivalent group in which two to six aromatic rings are bonded or a derivative thereof; A6 to A9 represent a group in which one to ten aromatic hydrocarbon groups, heterocyclic groups, or a derivative thereof are bonded.

11. The organic electroluminescence display unit of claim 3 , wherein the blue organic light emitting layer is made of a compound expressed in Formula 4:

where R1 to R6 represent a hydrogen atom, a halogen atom, a hydroxyl group, a cyano group, a nitro group; a group having a carbonyl group with a carbon number of 20 or less; a group having a carbonyl ester group; an alkyl group, an alkenyl group, an alkoxyl group or a derivative thereof; a group having a silyl group with a carbon number of 30 or less; or a group having an aryl group, a group having a heterocyclic group, a group having an amino group, or a derivative thereof.

12. A method of manufacturing an organic electroluminescence display unit, comprising:

forming a respective lower electrode on a substrate for each of a first blue organic electroluminescence device and a second organic electroluminescence device of a color different from blue;

forming a respective first hole injection/transport layer on the lower electrode for each of the first blue organic electroluminescence device and the second organic electroluminescence device;

forming a respective organic light emitting layer of the color different from blue on the first hole injection/transport layer for the second organic electroluminescence device;

forming a second hole injection/transport layer made of a low molecular material on the entire surfaces of the organic light emitting layer of the color different from blue and the first hole injection/transport layer for the first blue organic electroluminescence device;

forming a blue organic light emitting layer on the entire surface of the second hole injection/transport layer; and

forming, in sequence, an electron injection/transport layer and an upper electrode on the entire surface of the blue organic light emitting layer.

13. The method of claim 12 , wherein the organic light emitting layer of the color different from blue is formed by a coating method.

14. The method of claim 12 , wherein the organic light emitting layer of the color different from blue is formed using a mixture including the low molecular material and a polymer material.

15. The method of claim 12 , wherein the second hole injection/transport layer is formed by an evaporation method.

16. The method of claim 12 , wherein the blue organic light emitting layer is formed by an evaporation method.