Tdk Corporation

Etsuo Mitsuhashi

Michio Arai

Isamu Kobori

Masatada Yodogawa

Kentaro Sawamura

Nobuyuki Miki

Masahiro Kitajima

Hiroshi Yamamoto

Shinichi Sato

Masaru Nanao

Ryoichi Kondo

Akio Okamura

To realize an organic EL device having an excellent hole injection efficiency, improved luminous efficiency, low operating voltage, and low cost, the invention provides an organic EL device comprising a hole injecting electrode, an electron injecting electrode, and at least one organic layer between the electrodes, at least one of the organic layer having a light emitting function. The device further has a high resistance inorganic hole injecting layer between the hole injecting electrode and the organic layer. The high resistance inorganic hole injecting layer is capable of blocking electrons and has conduction paths for carrying holes.

Organic electroluminescent device with high resistance inorganic hole injecting layer

The organic EL device of the present invention fulfills the object of realizing an organic EL device which exhibits an excellent hole injecting efficiency and an improved light emitting efficiency and which can be operated at a low drive voltage and manufactured at a reduced cost. In order to attain such object, the organic EL device comprises a hole injecting electrode, a negative electrode, and one or more organic layers between the electrodes wherein at least one of said organic layers has a light emitting function. A high resistivity inorganic hole injecting layer is provided between said hole injecting electrode and the organic layer. This layer has conduction paths for electron blockage and hole transportation. An inorganic insulative electron injecting and transporting layer is provided between the light emitting layer and the negative electrode. This layer contains at least one oxide selected from strontium oxide, magnesium oxide, calcium oxide, lithium oxide, rubidium oxide, potassium oxide, sodium oxide and cesium oxide as its main component.

Organic electroluminescent device

An organic EL device has a hole injecting electrode, an electron injecting electrode, at least one organic layer between the electrodes, and an inorganic insulating hole injecting and transporting layer between the hole injecting electrode and the organic layer. The inorganic insulating hole injecting and transporting layer contains silicon oxide and/or germanium oxide as a main component, the main component being represented by (Si Ge )O wherein 0&lE;x&lE;1 and 1.8&lE;y&lE;2.5, and further contains 0.01 to 2% by weight of at least one element selected from among Ar, Kr, Xe, and Ne. The device has the advantages of both organic and inorganic materials, a long lifetime, improved efficiency, low operating voltage, and low cost, and can provide a high luminance of light emission when applied to displays of the time-division driving mode, and realize large screen, high definition displays.

An organic EL device comprises a substrate, a hole injecting electrode and an electron injecting electrode formed on the substrate and at least an organic layer taking part in light emitting function and located between these electrodes. Between the electron injecting electrode and the organic layer there is an inorganic insulating electron injecting layer comprising as a main component an oxide having an electron affinity of up to 3 eV with a stabilizing component added thereto. The organic EL device possesses the merits of both an organic material and an inorganic material, and has an extended life, an improved efficiency, a low driving voltage, and so is of great practical value.

The object of the invention is to provide an organic EL device which possesses the merits of both an organic material and an inorganic material, has an extended life, an improved efficiency, a low driving voltage and high luminance, and is fabricated at low cost. This object is achieved by the provision of an organic EL device comprising a substrate, a hole injecting electrode and a cathode formed on the substrate, and at least one organic layer located between these electrodes. An inorganic insulating electron injecting layer is located between the cathode and the organic layer. The inorganic insulating electron injecting layer comprises as an oxide having a low work function at least one oxide having a work function of lower than 2.5 eV, and as an oxide having a high work function at one oxide having a work function of 2.5 to 4 eV.

An object of the invention is to achieve an organic EL device which has an extended life, weather resistance, high stability, and high efficiency, and is inexpensive as well. This object is accomplished by the provision of an organic EL device comprising a substrate, a pair of a hole injecting electrode and a cathode formed on the substrate, and an organic layer located between these electrodes and taking part in at least a light emission function, wherein between the organic layer and the cathode there is provided an inorganic insulating electron injecting and transporting layer comprising a first component comprising at least one oxide selected from the group consisting of lithium oxide, rubidium oxide, potassium oxide, sodium oxide and cesium oxide, a second component comprising at least one oxide selected from the group consisting of strontium oxide, magnesium oxide and calcium oxide, and a third component comprising silicon oxide and/or germanium oxide.

To realize an organic EL device having an excellent electron injection efficiency, improved luminous efficiency, low operating voltage, and low cost, the invention provides an organic EL device comprising a hole injecting electrode, an electron injecting electrode, and at least one organic layer between the electrodes, at least one of the organic layer having a light emitting function. The device further has a high resistance inorganic electron injecting layer between the electron injecting electrode and the organic layer. The high resistance inorganic electron injecting layer contains as a first component an oxide of at least one element selected from alkali metal elements, alkaline earth metal elements and lanthanide elements, having a band gap of up to 4 eV and as a second component at least one element selected from Ru, V, Zn, Sm, and In and is capable of blocking holes and has conduction paths for carrying electrons.

Organic electroluminescent device with a high resistant inorganic electron injecting layer

The object of the invention is to provide an organic EL device which possesses the merits of both an organic material and an inorganic material, has high efficiency and an extended life, and can be fabricated at low cost. This object is achieved by the provision of an organic EL device comprising a hole injecting electrode, an electron injecting electrode and an organic layer interleaved between these electrodes and including at least a light emitting layer. A high-resistance inorganic electron transporting layer is interleaved between the light emitting layer and the electron injecting electrode and includes a conduction path for blocking holes and transporting electrons. An organic electron injecting layer is interleaved between the high-resistance inorganic electron transporting layer and the electron injecting electrode.

The object of the invention is to provide a high-efficiency, long-life yet low-cost organic EL device which possesses the merits of both an organic material and an inorganic material. This object is achieved by the provision of an organic EL device which comprises a hole injecting electrode and an electron injecting electrode between which an organic layer having at least a light emitting layer is provided, an inorganic insulating electron transporting layer provided between the light emitting layer and the electron injecting layer, a hole injecting and transporting layer provided between the light emitting layer and the hole injecting electrode, and an organic electron injecting layer provided between the inorganic insulating electron transporting layer and the electron injecting layer.

An organic EL device has a hole injecting electrode, an electron injecting electrode, an organic layer between the electrodes, and an inorganic insulating hole injecting layer between the hole injecting electrode and the organic layer. The inorganic insulating hole injecting layer contains silicon oxide or germanium oxide or a mixture thereof as a main component, and the main component is represented by (Si,Ge,)O,wherein 0&lE;x&lE;1 and 1.7&lE;y&lE;2.2. The hole injecting layer further contains Cu, Fe, Ni, Ru, Sn, Au or a mixture thereof, The device has advantages including a long lifetime, improved efficiency, low operating voltage, and low cost, and is suited for use as high-performance flat-panel color displays.

Organic electoluminescent device with inorganic insulating hole injecting layer

The invention provides an organic EL device comprising a hole injecting electrode, a negative electrode, at least one organic layer between the electrodes, the organic layer including a light emitting layer having a light emitting function, and a hole injecting and transporting layer containing a hole transporting organic material and an inorganic insulative hole injecting and transporting layer formed of an inorganic material between the hole injecting electrode and the light emitting layer. The inorganic insulative hole injecting and transporting layer contains silicon oxide and/or germanium oxide as a main component, the main component having an average composition represented by the formula: (Si,Ge,)O,wherein 0&lE;x&lE;1 and 1<y&lE;2. This construction enables an organic EL device having better performance than prior art devices having hole injecting and transporting layers using organic materials, a long life, weather resistance, high stability, high efficiency, and low cost.

Organic electroluminescent device with silicone oxide and/or germanium oxide insulative layer

An organic EL device has a hole injecting electrode (,), an electron injecting electrode (,), an organic layer (,) between the electrodes, and an inorganic insulating hole injecting layer (,) between the hole injecting electrode (,) and the organic layer (,). The inorganic insulating hole injecting layer (,) consists essentially of silicon oxide or germanium oxide or a mixture of silicon oxide and germanium oxide in an average composition represented by (Si,Ge,)O,wherein x and y are 0&lE;x&lE;1 and 1.7&lE;y&lE;1.99, as analyzed by Rutherford back-scattering. The device has the advantages of both organic and inorganic materials as well as a long lifetime, improved efficiency, low operating voltage, and low cost.

The invention provides an organic EL device comprising a substrate, a hole injecting electrode and a negative electrode formed on the substrate, an organic layer containing an organic material between the electrodes, the organic layer including a light emitting layer having at least a light emitting function, and an electron injecting and transporting layer containing an electron transporting organic material and an inorganic insulative electron injecting and transporting layer formed of an inorganic material between the negative electrode and the light emitting layer. The inorganic insulative electron injecting and transporting layer contains at least one oxide selected from the group consisting of lithium oxide, rubidium oxide, potassium oxide, sodium oxide, cesium oxide, strontium oxide, magnesium oxide, and calcium oxide as a main component, and silicon oxide, germanium oxide or a mixture of silicon oxide and germanium oxide as a stabilizer. This construction ensures better performance than prior art devices having electron injecting and transporting layers using organic materials, a high efficiency, long life, weather resistance, and high stability.

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Tokyo, Japan

Etsuo Mitsuhashi