Classifications

• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B33/00—Electroluminescent light sources
  • H05B33/12—Light sources with substantially two-dimensional [2D] radiating surfaces
  • H05B33/26—Light sources with substantially two-dimensional [2D] radiating surfaces characterised by the composition or arrangement of the conductive material used as an electrode
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
  • H10K50/00—Organic light-emitting devices
  • H10K50/10—OLEDs or polymer light-emitting diodes [PLED]
  • H10K50/17—Carrier injection layers

Definitions

• the present invention relates to electrode structures for an organic light emitting diode (OLED) device.
• the present invention relates to an improved anode structure for an OLED device.
• Fig. 1 discloses a known OLED device 10.
• the OLED device 10 includes a glass substrate 11.
• a transparent hole-injecting anode or electrode 12 formed of indium-tin oxide (ITO) is located on the glass substrate 11.
• An organic stack 13 is located on the anode 12.
• the anode 12 forms the first or bottom layer of the stack 13.
• a metal cathode 14 is located on top of the organic stack 13. In the device 10, light is emitted in a downward direction through the electrode 12 and the glass substrate 11.
• ITO indium-tin oxide
• OLED require two electrodes, an anode 12 and a cathode 14, at least one of which must be transparent to allow light to escape.
• the anode 12, which must supply holes to the emitting region, is usually formed from a material with high work function, since this will lead to a low energy for hole injection.
• the cathode 14, which must supply electrons to the emitting region, is usually formed from a material with low work function, which will facilitate electron injection.
• ITO Indium tin oxide
• ITO injection efficiency of ITO, and consequently the luminescent efficiency of the OLED, is enhanced by pretreating the ITO with an oxygen plasma, which ensures that there is an excess of oxygen at the interface with the organic stack 13.
• the excess of oxygen appears to contribute to the instability of such OLEDs because the oxygen can migrate and react with the organic materials.
• ITO has also been used in conjunction with thin metal interlayers to form cathode contacts, where the thin metal is of a low work function material to provide electron injection.
• the present invention is directed to an improved organic light emitting diode device.
• the organic light emitting diode device includes a first electrode, a second electrode, and an
• stack may include hole transport materials located on one side of the stack and electron
• the improvement includes a thin
• the organic light emitting diode device according to the present invention has
• the thin layer of high work function material may be formed from a material selected
• the thin layer of high work function is selected from the group consisting of Mo and alloys of Mo.
• the thin layer of high work function is selected from the group consisting of Mo and alloys of Mo.
• material may be formed from a material selected from the group consisting of W and alloys
• the thin layer of high work function material may be formed from a
• thin layer of the high work function material may have a thickness of less than 100 A.
• the first electrode may be a transparent electrode and the second electrode may be
• the second electrode may be formed from a low work function material.
• the present invention is also directed to an improved electrode structure for an
• the electrode may comprise an electrode layer, and a thin
• the thin layer of a high work function material located adjacent the electrode layer.
• high work function material may be formed from a material selected from the group
• the thin layer of high work function material may be any material consisting of Mo and alloys of Mo.
• the thin layer of high work function material may be any material consisting of Mo and alloys of Mo.
• layer of high work function material may be formed from a material selected from the group
• the electrode structure may be an
• the anode may be a transparent anode.
• the thin layer of the high work function material has a thickness of less than 100 A.
• the electrode structure may be a
• the present invention is also directed to an organic light emitting diode device having
• the device includes an anode layer formed from a high work function
• the anode layer may be formed from a material selected from the group consisting of:
• the anode layer may be formed from a material selected
• the anode layer may be formed from a
• Fig. 1 is a schematic view of a known organic light emitting diode device
• Fig. 2 is a schematic view of an organic light emitting diode device in accordance
• Fig.2 discloses an organic light emitting diode device 20 according to an embodiment
• the OLED device 20 includes a substrate 21.
• a first electrode 22 is provided on the substrate 21.
• An intermediate layer 24 is located on the organic stack 23.
• second electrode 25 is located on top of the intermediate layer 24.
• the second electrode 25 is an anode and is formed from ITO. It, however, is
• IZO IZO
• the intermediate layer 24 is provided
• the layer 24 reduces oxygen migration from the second electrode 25 and
• the intermediate layer 24 is preferably a thin layer of high work function material.
• the layer 24 is preferably formed from Mo or alloys of Mo.
• the present invention however,
• These materials include, but are not limited to W, Nb, Zr, Co, Zn, Tc, Hf, Ta, Cr,
• Oxides and nitrides of these materials may also be used to improve
• the second electrode 25 formed from ITO is used only for its
• the intermediate layer 24 must be sufficiently thin (e.g. a thickness of than 100 A) to permit light to escape through the second electrode and for
• Oxides and nitrides are often insulating so the thickness must be controlled so
• the first electrode 22 may then be opaque.
• the second electrode 25 is not transparent. Accordingly, the
• first electrode 21 which functions as a cathode, must be transparent or semitransparent to

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• Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Electroluminescent Light Sources (AREA)

Applications Claiming Priority (3)

Publications (1)

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• 1999
  • 1999-02-24 EP EP99909560A patent/EP1088320A1/de not_active Withdrawn
  • 1999-02-24 JP JP2000550128A patent/JP2002516459A/ja active Pending
  • 1999-02-24 WO PCT/US1999/003900 patent/WO1999060599A1/en not_active Ceased
  • 1999-02-24 KR KR1020007012865A patent/KR20010071276A/ko not_active Withdrawn
  • 1999-02-24 CN CN99808804A patent/CN1321325A/zh active Pending

Non-Patent Citations (1)

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