Organic Light Emitting Device With a Plurality of Organic Electroluminescent Units Stacked Upon Each Other

• US 20090009072A1
• Filed: 12/22/2006
• Published: 01/08/2009
• Est. Priority Date: 12/23/2005
• Status: Abandoned Application

• Current Assignee: Novaled AG
• Original Assignee: Novaled AG
• Inventors: Wellmann, Philipp, Werner, Ansgar, Murano, Sven, He, Gufeng
• Application Number:
  US12/158,582
• Publication Number:
  US 20090009072A1
• Time in Patent Office: Days
• US Class Current: 313/504
• CPC Class Codes: H10K 2101/10 Triplet emission
• CPC Class Codes: H10K 50/11 characterised by the electroluminescent [EL] layers
• 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

Abstract

The invention relates to an organic light emitting device comprising an anode (2); a cathode (4); and a plurality of organic electroluminescent units (3.1, . . . , 3.m; m≧2) provided upon each other in a stack or an inverted stack between said anode (2) and said cathode (4) each of said organic electroluminescent units (3.1, . . . , 3.m) comprising an electroluminescent zone; wherein at least some of the organic electroluminescent units (3.2, . . . , 3.m) comprise a p-type doped hole transporting-layer and/or an n-type doped electron-transporting layer.

Claims

1. An organic light emitting device comprising:

an anode (2);

a cathode (4); and

a plurality of organic electroluminescent units (3.1, . . . , 3.m;

m=2, 3, . . . ) provided upon each other in a stack or an inverted stack between said anode (2) and said cathode (4) each of the organic electroluminescent units (3.1, . . . , 3.m) comprising two single doped transporting-layers, namely a single p-type doped hole-transporting layer (HTL) and a single n-type doped electron-transporting layer (ETL), and an electroluminescent zone (EML) formed between the single p-type doped hole-transporting layer (HTL) and the single n-type doped electron-transporting layer (ETL);

wherein;

for the first organic electroluminescent unit (3.1), the single p-type doped hole-transporting layer (HTL) is in direct contact with the anode (2);

for the mth organic electroluminescent unit (3.m), the single n-type doped electron-transporting layer (ETL) which is in direct contact with the cathode (4); and

for all of said organic electroluminescent units (3.1, . . . , 3.m), within the stack or the inverted stack adjacent single doped transporting layers provided in two adjacent organic electroluminescent units and adjacent to each other are in direct contact, thereby forming a p-n-junction between an adjacent single p-type doped hole-transporting-layer (HTL) provided in one of the two adjacent organic electroluminescent units and an adjacent single n-type doped electron-transporting layer (ETL) provided in the other one of the two adjacent organic electroluminescent units.

2. Organic light emitting device according to claim 1, wherein at least one of said organic electroluminescent units (3.1, . . . , 3.m) further comprises at least one of the following layers:

a hole-injection layer (HIL), an electron-injection layer (EIL), an interlayer in between the single p-type doped hole-transporting layer and the electroluminescent zone, and a further interlayer between the single n-type doped electron-transporting layer and the electroluminescent zone, and wherein the at least one layer is provided between the single p-type doped hole-transporting-layer (HTL) and the single n-type doped electron-transporting layer (ETL).

3. Organic light emitting device according to claim 1, wherein for at least one of said organic electroluminescent units (3.1, . . . , 3.m) the electroluminescent zone is formed by a multilayer structure of organic layers.

4. Organic light emitting device according to claim 1, wherein for at least one of said organic electroluminescent units (3.1, . . . , 3.m) the single p-type doped hole-transporting layer is doped with an acceptor dopant having a high molecular weight, namely a weight of more than about 300 g/mol.

5. Organic light emitting device according to claim 1, wherein for at least one of said organic electroluminescent units (3.1, . . . , 3.m) the single n-type doped electron-transporting layer is doped with a donator dopant having a high molecular weight, namely a weight of more than about 300 g/mol.

6. Organic light emitting device according to claim 1, wherein for at least one of said organic electroluminescent units (3.1, . . . , 3.m) the single n-type doped electron-transporting layer is doped with an alkali metal or an alkali metal compound with a molar ratio of <

1;

3 of the alkali metal or the alkali metal compound in respect to a matrix material.

7. Organic light emitting device according to claim 1, wherein for at least one of said organic electroluminescent units (3.1, . . . , 3.m) the electroluminescent zone is formed from a material of small molecules and/or from organic polymers.

8. Organic light emitting device according to claim 1, wherein for at least one of said organic electroluminescent units (3.1, . . . , 3.m) the single p-type doped hole-transporting-layer (HTL) and the single n-type doped electron-transporting layer (ETL) are made of a matrix material which is the same material for the single p-type doped hole-transporting-layer (HTL) and the single n-type doped electron-transporting layer (ETL), where for the single p-type doped hole-transporting-layer (HTL) the matrix material is p-doped, and for the single n-type doped electron-transporting layer (ETL) the matrix mate