Organic light-emitting device

Patent metadata

Field	Value
Publication number	US-9331296-B2
Application number	US-201113634505-A
Country	US
Kind code	B2
Filing date	Mar 14, 2011
Priority date	Mar 31, 2010
Publication date	May 3, 2016
Grant date	May 3, 2016

Abstract

Aspects of the present invention provide a blue organic light-emitting device having a continuous operation lifetime.
An organic light-emitting device includes a light-emitting layer containing a dopant having the ability to trap electrons or holes, and a hole-blocking layer or electron-blocking layer, in which the difference between the LUMO of the dopant and the LUMO of a host material, the size relationship between the HOMO of the host material and the HOMO of the dopant, and the difference between the T 1 of the host material and the T 1 of the hole-blocking layer or between the T 1 of the host material and the T 1 of the electron-blocking layer, are specified.

First claim

The invention claimed is:

1. An organic light-emitting device comprising:
a pair of electrodes having an anode and a cathode;
a light-emitting layer arranged between the pair of electrodes, the light-emitting layer containing a host material and a blue-fluorescent dopant material having the ability to trap electrons; and
a hole-blocking layer adjacent to the light-emitting layer,
wherein the energy of the lowest unoccupied molecular orbital of the host material (LUMO (host)) and the energy of the LUMO of the blue-fluorescent dopant material (LUMO (dopant)) satisfy the following expression:
|LUMO(dopant)|−|LUMO(host)|>0.15 eV,

the energy of the highest occupied molecular orbital of the host material (HOMO (host)) and the energy of the HOMO of the blue-fluorescent dopant material (HOMO (dopant)) satisfy the following expression:
|HOMO(host)|<|HOMO(dopant)|,

the energy of the lowest excited triplet state of the host material (T 1 (host)) and the energy of the lowest excited triplet state of the hole-blocking layer (T 1 (HBL)) satisfy the following expression:
T1(host)−T1(HBL)>0.1 eV,

the host material and a material for the hole-blocking layer are different hydrocarbon compounds, each of the hydrocarbon compounds having a plurality of mono- or higher-valent unsubstituted or alkyl-substituted aromatic hydrocarbon moieties, and the aromatic hydrocarbon moieties being linked together only by a single bond, and
a substructure containing the single bond and the aromatic hydrocarbon moieties linked together by the single bond is represented only by general formula [1] or [2]:

(wherein thick lines illustrated in formulae [1] and [2] each indicate the single bond).

2. The organic light-emitting device according to claim 1 , wherein the minimum exposed surface area of the single bond of each of the host material and the material for the hole-blocking layer is higher than 87 Å 2 .

3. The organic light-emitting device according to claim 1 , wherein the blue-fluorescent dopant material having the ability to trap electrons is a hydrocarbon compound having the substructure containing a fluoranthene skeleton.

4. An organic light-emitting device comprising:
a pair of electrodes having an anode and a cathode,
a light-emitting layer arranged between the pair of electrodes, the light-emitting layer containing a host material and a blue-fluorescent dopant material having the ability to trap holes, and
an electron-blocking layer adjacent to the light-emitting layer,
wherein the energy of the lowest unoccupied molecular orbital of the host material (LUMO (host)) and the energy of the LUMO of the blue-fluorescent dopant material (LUMO (dopant)) satisfy the following expression:
|LUMO(host)|>|LUMO(dopant)|,

the energy of the highest occupied molecular orbital of the host material (HOMO (host)) and the energy of the HOMO of the blue-fluorescent dopant material (HOMO (dopant)) satisfy the following expression:
|HOMO(host)|−|HOMO(dopant)|>0.15 eV,

the energy of the lowest excited triplet state of the host material (T 1 (host)) and the energy of the lowest excited triplet state of the electron-blocking layer (T 1 (EBL)) satisfy the following expression:
T1(host)−T1(EBL)>0.1 eV,

the host material and a material for the electron-blocking layer are different hydrocarbon compounds, each of the hydrocarbon compounds having a plurality of mono- or higher-valent unsubstituted or alkyl-substituted aromatic hydrocarbon moieties, and the aromatic hydrocarbon moieties being linked together only by a single bond, and
a substructure containing the single bond and the aromatic hydrocarbon moieties linked together by the single bond is represented only by general formula [1] or [2]:

(wherein thick lines illustrated in formulae [1] and [2] each indicate the single bond).

5. The organic light-emitting device according to claim 4 , wherein the minimum exposed surface area of the single bond of each of the host material and the material for the electron-blocking layer is higher than 87 Å 2 .

6. The organic light-emitting device according to claim 1 , wherein the host material contained in the light-emitting layer has an energy of the lowest excited triplet state T 1 of 2.5 eV or less.

Assignees

• Okajima Maki
• Okinaka Keiji
• Takahashi Tetsuo
• Muta Hajime
• Iwasaki Yohei
• Nakasu Minako
• Yamada Naoki
• Nishide Yosuke
• Canon Kk

Inventors

• Okajima Maki
• Okinaka Keiji
• Takahashi Tetsuo
• Muta Hajime
• Iwasaki Yohei
• Nakasu Minako
• Yamada Naoki
• Nishide Yosuke

Classifications

• H10K50/181

  Electron blocking layers · CPC title

• H10K50/11

  characterised by the electroluminescent [EL] layers · CPC title

• C09K11/06 Primary

  containing organic luminescent materials · CPC title

• H01L51/0054

  Electricity · mapped topic

• H01L51/5096

  Electricity · mapped topic