ELECTRONIC DEVICE WITH A LAYER STRUCTURE OF ORGANIC LAYERS

• US 20090045728A1
• Filed: 12/22/2006
• Published: 02/19/2009
• Est. Priority Date: 12/23/2005
• Status: Active Grant

• Current Assignee: Novaled AG
• Original Assignee: Novaled AG
• Inventors: Birnstock, Jan, Werner, Ansgar, Murano, Sven, Burghart, Markus
• Granted Patent: US 7,830,089 B2
• Time in Patent Office: Days
• US Class Current: 313/504
• CPC Class Codes: H10K 50/125 specially adapted for multicolour light emission, e.g. for emitting white light
• CPC Class Codes: H10K 50/155 comprising dopants
• CPC Class Codes: H10K 50/165 comprising dopants
• CPC Class Codes: H10K 50/19 Tandem OLEDs
• CPC Class Codes: H10K 71/30 Doping active layers, e.g. electron transporting layers
• CPC Class Codes: H10K 85/30 Coordination compounds
• CPC Class Codes: H10K 85/342 comprising iridium
• CPC Class Codes: H10K 85/615 Polycyclic condensed aromatic hydrocarbons, e.g. anthracene
• CPC Class Codes: H10K 85/633 comprising polycyclic condensed aromatic hydrocarbons as substituents on the nitrogen atom
• CPC Class Codes: H10K 85/657 Polycyclic condensed heteroaromatic hydrocarbons

Abstract

The invention relates to an electronic device comprising a layer structure of organic layers, wherein said layer structure comprises a p-n-junction between an n-type doped organic layer provided as an organic matrix material doped with an n-type dopant and a p-type doped organic layer provided as a further organic matrix material doped with a p-type dopant, and wherein the n-type dopant and the p-type dopant both are molecular dopants, a reduction potential of the p-type dopant is equal or larger than about 0 V vs. Fc/Fc⁺, and an oxidation potential of the n-type dopant is equal or smaller than about −1.5 V vs. Fc/Fc⁺.

Claims

1. An electronic device comprising a layer structure of organic layers, wherein said layer structure comprises a p-n-junction between an n-type doped organic layer provided as an organic matrix material doped with an n-type dopant and a p-type doped organic layer provided as a further organic matrix material doped with a p-type dopant, and wherein the n-type dopant and the p-type dopant both are molecular dopants, characterized in that

a reduction potential of the p-type dopant is equal or larger than about 0 V vs. Fc/Fc⁺,

an oxidation potential of the n-type dopant is equal or smaller than about −

1.5 V vs. Fc/Fc⁺, and

at least one of the evaporation temperature of the n-type dopant and the evaporation temperature of the p-type dopant is higher than about 120°

C.

2. Electronic device according to claim 1, wherein a molecular weight of the n-type dopant and/or a molecular weight of the p-type dopant are larger than about 300 g/mol.

3. Electronic device according to claim 1, wherein the reduction potential of the p-type dopant is equal or larger than about 0.18 V vs. Fc/Fc⁺, preferably equal or larger than about 0.24 V vs. Fc/Fc⁺.

4. Electronic device according to claim 1, wherein the oxidation potential of the n-type dopant is equal or smaller than about −

2.0 V vs. Fc/Fc⁺, preferably equal or smaller than about −

2.2 V vs. Fc/Fc⁺.

5. Electronic device according to claim 1, wherein a glass transition temperature (T_g) of the matrix material and/or a glass transition temperature (T_g) of the further matrix material are equal or larger than about 75°

C., preferably equal or larger than about 100°

C., more preferably equal or larger than about 120°

C.

6. Electronic device according to claim 1, wherein the matrix material and the further matrix material are made of the same material.

7. Electronic device according to claim 1, wherein the n-type doped organic layer is provided as a multilayer structure.

8. Electronic device according to claim 1, wherein the p-type doped organic layer is provided as a multilayer structure.

9. Electronic device according to claim 1, wherein the layer structure is provided in an organic light emitting device.

10. Electronic device according to claim 9, wherein the organic light emitting device comprises an anode (2), a cathode (4), and a plurality of organic electroluminescent units (3.1, . . . , 3.m;

m≧

2) each comprising an electroluminescent zone (EML), where the organic electroluminescent units are provided upon each other in a stack or an inverted stack between the anode (2) and the cathode (4), and where the p-n-junction is provided at an interface between adjacent organic electroluminescent units.

11. Electronic device according to claim 10, wherein for m>

2;

at least organic electroluminescent units (3.2, . . . , 3.m−

1) not adjacent to the anode (2) or the cathode (4) comprise the p-type doped organic layer as a p-type doped hole transporting-layer (HTL), the n-type doped organic layer as an n-type doped electron-transporting layer (ETL), and the electroluminescent zone (EML) formed between the p-type doped hole transporting layer (HTL) and the n-type doped electron transporting layer (ETL);

in the stack or the inverted stack the n-type doped electron-transporting layer (ETL) of the k^th (2≦

k≦

m−

2) organic electroluminescent unit (3.k) is directly followed by the p-type doped hole-transporting layer (HTL) of the (k+1)^th organic electroluminescent unit (3.k+1), thereby providing a direct contact between the n-type doped electron-transporting layer (ETL) of the k^th organic electroluminescent unit (3.k) with the p-type doped hole-transporting layer (HTL) of the (k+1)^th organic electroluminescent unit (3.k+1); and

the first organic electroluminescent unit (3.1) comprises an n-type doped electron-transporting layer (ETL) which is in contact with the p-type doped hole-transporting layer (HTL) of the second organic electroluminescent unit (3.2), and the m^th organic electroluminescent unit (3.m) comprises a p-type doped hole-transporting layer (HTL) which is in contact with the n-type doped electron-transporting layer (ETL) of the (m−

1)^th organic electroluminescent unit (3.m−

1).

12. Electronic device according to claim 10, wherein for m=2:

a first electroluminescent unit (3.1) comprises the n-type doped organic layer as an n-type doped electron-transporting layer (ETL);

a second electroluminescent unit (3.2) comprises the p-type doped organic layer as a p-type doped hole transporting-layer (HTL); and

the n-type doped electron-transporting layer (ETL) of the first electroluminescent unit (3.1) is in contact with the p-type doped hole-transporting layer (HTL) of the second organic electroluminescent unit (3.2), thereby providing a p-n-junction between the two adjacent organic electroluminescent units (3.1, 3.2).

13. Electronic device according to claim 10, wherein at least one of the organic electroluminescent units (3.1, . . . , 3.m;

3.1, 3.2) further comprises at least one of the following layers;

a hole-injection layer (HIL), an electron-injection layer (EIL), an interlayer in between the p-type doped hole-transporting layer and the electroluminescent zone, and a further interlayer between the n-type doped electron-transporting layer and the electroluminescent zone.

14. Electronic device according to claim 10, wherein for at least one of the organic electroluminescent units (3.1, . . . , 3.m;

3.1, 3.2) the electroluminescent zone is formed by a multilayer structure of organic layers.

15. Electronic device according to claim 10, wherein for at least one of the organic electroluminescent units (3.1, . . . , 3.m;

3.1, 3.2) the electroluminescent zone is formed from a material of small molecules and/or from organic polymers.

16. Electronic device according to claim 10, wherein the organic electroluminescent units (3.1, . . . , 3.m;

3.1, 3.2) emit light of different wavelengths.

17. Electronic device according to claim 16, wherein white light is emitted by the plurality of organic electroluminescent units (3.1, . . . , 3.m;

3.1, 3.2).

18. Electronic device according to claim 1, wherein at least one of the evaporation temperature of the n-type dopant and the evaporation temperature of the p-type dopant is higher than about 140°

C.