Organic electroluminescent element

• US 8,987,726 B2
• Filed: 02/13/2014
• Issued: 03/24/2015
• Est. Priority Date: 07/23/2009
• Status: Active Grant

• Current Assignee: Kaneka Corporation
• Original Assignee: Kaneka Corporation
• Inventors: Nagai, Naomi, Nishida, Masami, Miura, Nobuhito, Matsumoto, Toshio, Umezaki, Hirotaka
• Primary Examiner(s): Huynh, Andy
• Application Number:
  US14/180,288
• Publication Number:
  US 20140225092A1
• Time in Patent Office: 404 Days
• Field of Search: 257/40, 257/103, 257/642, 257/E51.001
• US Class Current: 257/40
• CPC Class Codes: H10K 50/19 Tandem OLEDs
• CPC Class Codes: H10K 85/30 Coordination compounds
• CPC Class Codes: H10K 85/6572 comprising only nitrogen in the heteroaromatic polycondensed ring system, e.g. phenanthroline or carbazole

Abstract

Provided is a high-luminance, long-life laminated organic electroluminescent element. The organic electroluminescent element has a composition in which a plurality of light-emitting units, including at least one organic light-emitting layer, are laminated between a positive electrode and a negative electrode, and in which a linking layer is held between the respective light-emitting units. The linking layer is formed by laminating, in succession from the positive electrode side, an electron generating/transport section, an intermediate layer, and a hole generating/transport section, which contain at least one metal selected from a group consisting of an alkali metal, alkaline earth metal, rare earth metal, alloy of these metals, and compound of these metals. Preferably the intermediate layer contains an electrical insulating non-semiconductive substance having a specific resistance which is between 1.0×10² Ω·cm and 1.0×10⁹ Ω·cm.

Claims

1. An organic electroluminescent element, comprising

an anode,

a cathode,

plural light-emitting units that are stacked between the anode and the cathode, each light-emitting unit comprising at least one organic light-emitting layer, and

a connection layer sandwiched between the respective light-emitting units,

wherein in the connection layer, the following are successively stacked from an anode side:

an electron-generating and transporting section which is a mixed layer of;

at least one selected from the group consisting of alkali metals, alkaline earth metals, rare earth metals, and alloys of these metals, and compounds of these metals excluding metal oxide compounds; and

an organic compound which is an electron-transporting material;

a single layer consisting of only an electron-transporting material which is a charge-transporting organic material; and

a hole-generating and transporting section.

2. The organic electroluminescent element according to claim 1, wherein the hole-generating and transporting section comprises an azatriphenylene derivative represented by the following general formula (I):

3. The organic electroluminescent element according to claim 1, wherein the hole-generating and transporting section is a metal oxide layer having a hole-injecting ability.

4. The organic electroluminescent element according to claim 3, wherein a metal oxide which forms the metal oxide layer having the hole-injecting ability comprises at least one selected from the group consisting of molybdenum oxide, ruthenium oxide, manganese oxide, tungsten oxide, and vanadium oxide.