# US 2013/0153881 A1 · Organic light-emitting devices and light source systems

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 2013/0153881 A1
- Document ID: US20130153881A1
- Status: Published application
- Kind: A1
- Application number: 13/818,646
- Filed: 2011-08-16
- Published: 2013-06-20
- Earliest claimed: 2010-09-24
- Assignees: Hitachi, Ltd.
- Inventors: Naoya Tokoo; Shingo Ishihara; Sukekazu Aratani; Hirotaka Sakuma
- Web page: https://patentgrep.com/patent/US20130153881A1

## CPC

- H10K 50/13: comprising stacked EL layers within one EL unit
- H10K 50/11: characterised by the electroluminescent [EL] layers
- H10K 50/18: Carrier blocking layers
- H10K 85/324: {comprising aluminium, e.g. Alq3}
- H10K 85/342: {comprising iridium}
- H10K 2101/10: Triplet emission
- H10K 2101/30: Highest occupied molecular orbital [HOMO], lowest unoccupied molecular orbital [LUMO] or Fermi energy values
- H10K: ORGANIC ELECTRIC SOLID-STATE DEVICES

## Abstract

The present invention provides an organic light-emitting device including a first electrode (101), a second electrode (102), organic multi-layers (105, 115) in which the organic multi-layers (105, 115) is formed between the first electrode (101) and the second electrode (102) and has a hole blocking layer (16), an emission layer (15), and an electron blocking layer (14), and the emission layer 15 is interposed between the hole blocking layer (16) and the electron blocking layer (14), a first light-emitting dopant is added to the hole blocking layer (16), a second light-emitting dopant is added to the emission layer (15), a third light-emitting dopant is added to the electron blocking layer (14), and the first light-emitting dopant and the third light-emitting dopant trap carriers penetrating the emission layer. According to the invention, the emission layer can emit light at high efficiency and deterioration of the emission layer can be suppressed.

## Claims

### Claim 1

An organic light-emitting device comprising:
a first electrode;
a second electrode;
organic multi-layers formed between the first electrode and the second electrode;
the organic multi-layers having a hole blocking layer, an emission layer, and an electron blocking layer; and
the emission layer being interposed between the hole blocking layer and the electron blocking layer;
wherein a first light-emitting dopant is added to the hole blocking layer,
a second light-emitting dopant is added to the emission layer,
a third light-emitting dopant is added to the electron blocking layer, and
the first light-emitting dopant and the third light-emitting dopant trap carriers that inject to the emission layer.

### Claim 2 (depends on 1)

An organic light-emitting device according to claim 1, wherein
an electron transport material is added to the hole blocking layer, and a hole transport material is added to the electron blocking layer, and the following relations (1) and (2) are satisfied when assuming the energy of the lowest occupied molecular orbital of the hole transport material as LUMO (EBL_host), the energy of the lowest occupied molecular orbital of the first light-emitting dopant as LUMO (EBL_dop), the energy of the highest occupied molecular orbital of the electron transport material as HOMO (HBL_host), and the energy of the highest occupied molecular orbital of the third light-emitting dopant as HOMO (HBL_dop):
LUMO(EBL_host)≦LUMO(EBL_dop) (1)
HOMO(HBL_host)≧HOMO(HBL_dop) (2)

### Claim 3 (depends on 1)

An organic light-emitting device according to claim 1, wherein
the following relations (3) and (4) are satisfied when assuming the lowest triplet energy state of the first light-emitting dopant as T1EBL-D, the lowest triplet energy state of the second light-emitting dopant as T1EML-D, and the lowest triplet energy state of the third light-emitting dopant as T1HBL-D:
T1EML—D≦T1EBL—D (3)
T1EML—D≦T1HBL—D (4)

### Claim 4 (depends on 1)

An organic light-emitting device according to claim 1, wherein the following relation (5) is satisfied when assuming the hole mobility in the emission layer as μh-EML and the electron mobility in the emission layer as μe-EML:
0.7μh—EML≧μe—EML≧1.3μh—EML (5)

### Claim 5 (depends on 1)

An organic light-emitting device according to claim 1, wherein
the following relation (6) and (7) are satisfied when assuming an energy barrier at the boundary between the hole blocking layer and the emission layer as φh and an energy barrier at the boundary between the emission layer and the electron blocking layer as φe:
Φh≦0.3eV (6)
Φe≦0.3eV (7)

### Claim 6 (depends on 1)

An organic light-emitting device according to claim 1, wherein
the emission color of the first light-emitting dopant, the emission color of the second light-emitting dopant, and the emission color of the third light-emitting dopant are identical.

### Claim 7 (depends on 1)

An organic light-emitting device according to claim 1, wherein
the following relations (8) and (9) are satisfied when assuming the dopant concentration of the first light-emitting dopant in the hole blocking layer as D1, the dopant concentration of the second light-emitting dopant in the emission layer as D2, and the dopant concentration of the third light-emitting dopant in the electron blocking layer as D3:
D1≦0.1D2 (8)
D3≦0.1D2 (9)

### Claim 8 (depends on 1)

An organic light-emitting device according to claim 1, wherein
the first light-emitting dopant, the second light-emitting dopant, and the third light-emitting dopant are blue phosphorescent materials.

### Claim 9 (depends on 8)

An organic light-emitting device according to claim 8, wherein
the blue phosphorescent material is FIr6 or FIrpic.

### Claim 10

An organic light-emitting device comprising:
a first electrode;
a second electrode;
organic multi-layers formed between the first electrode and the second electrode;
the organic multi-layers having a hole blocking layer, a first emission layer, a second emission layer, and an electron blocking layer; and
the first emission layer and the second emission layer being stacked and interposed between the hole blocking layer and the electron blocking layer;
wherein a first light-emitting dopant is added to the hole blocking layer,
a second light-emitting dopant is added to the first emission layer,
a third light-emitting dopant is added to the electron blocking layer,
a fourth light-emitting dopant is added to the second emission layer,
the first light-emitting dopant traps electrons that inject to the first emission layer, and
the third light-emitting dopant traps holes that inject to the second emission layer.

### Claim 11 (depends on 10)

An organic light-emitting device according to claim 10, wherein
the first light-emitting dopant is formed of a material identical with that of the second light-emitting dopant or the fourth light-emitting dopant, and the third light-emitting dopant is formed of a material identical with that of the second light-emitting dopant or the fourth light-emitting dopant.

### Claim 12 (depends on 10)

An organic light-emitting device according to claim 10, wherein
a third emission layer is formed between the first emission layer and the second emission layer, and a fifth light-emitting dopant is added to the third emission layer, whereby white light is emitted.

### Claim 13 (depends on 1)

A light source system including the organic light-emitting device according to claim 1 and a driving device.

### Claim 14

An organic light-emitting device comprising:
a first electrode;
a second electrode;
organic multi-layers;
a charge generation layer;
the organic multi-layers and the charge generation layer being stacked alternately between the first electrode and the second electrode;
the first electrode and the second electrode being in contact with the organic multi-layers;
the organic multi-layers having at least a hole blocking layer, an emission layer, and an electron blocking layer; and
the emission layer being stacked in plurality and interposed between the hole blocking layer and the electron blocking layer;
wherein a light-emitting dopant is added to the hole blocking layer, the emission layer, and the electron blocking layer, and the light-emitting dopant traps carriers that inject to the emission layer.