347results about How to "Solve low luminous efficiency" patented technology

Provided are an organic electroluminescence device, which shows high luminous efficiency, is free of any pixel defect, and has a long lifetime, and a material for an organic electroluminescence device for realizing the device. The material for an organic electroluminescence device is a compound having a n-conjugated heteroacene skeleton crosslinked with a carbon atom, nitrogen atom, oxygen atom, or sulfur atom. The organic electroluminescence device has one or more organic thin film layers including a light emitting layer between a cathode and an anode, and at least one layer of the organic thin film layers contains the material for an organic electroluminescence device.

Provided are an organic electroluminescence device, which: shows high luminous efficiency; is free of any pixel defect; and has a long lifetime, and a material for an organic electroluminescence device for realizing the device. The material for an organic electroluminescence device is a compound of a specific structure having a n-conjugated heteroacene skeleton crosslinked with a carbon atom, nitrogen atom, or oxygen atom. The organic electroluminescence device has one or more organic thin film layers including a light emitting layer between a cathode and an anode, and at least one layer of the organic thin film layers contains the material for an organic electroluminescence device.

Disclosed herein is a red phosphorescent compound represented by Formula 1 below:

wherein

is

R1 is selected from the group consisting of C₁-C₄ alkyl and C₁-C₄ alkoxy; R2, R3, R4 and R5 are independently selected from the group consisting of

hydrogen, C₁-C₄ alkyl and C₁-C₄ alkoxy; and

is selected from the group consisting of 2,4-pentanedione, 2,2,6,6,-tetramethylheptane-3,5-dione, 1,3-propanedione, 1,3-butanedione, 3,5-heptanedione, 1,1,1-trifluoro-2,4-pentanedione, 1,1,1,5,5,5-hexafluoro-2,4-pentanedione and 2,2-dimethyl-3,5-hexanedione.

Further disclosed herein is an organic electroluminescent (EL) device using the red phosphorescent compound.

An oxynitride phosphor consisting of a crystal containing at least one or more of Group II elements selected from the group consisting of Be, Mg, Ca, Sr, Ba and Zn, at least one or more of Group IV elements selected from the group consisting of C, Si, Ge, Sn, Ti, Zr and Hf, and a rare earth element being an activator R, thereby providing a phosphor which is excited by an excitation light source at an ultraviolet to visible light region and which has a blue green to yellow luminescence color that is wavelength converted.

Novel two-phase yellow phosphors are disclosed having a peak emission intensity at wavelengths ranging from about 555 nm to about 580 nm when excited by a radiation source having a wavelength ranging from 220 nm to 530 nm. The present phosphors may be represented by the formula a[Sr_x(M1)_1-x]_zSiO₄●(1-a)[Sr_y(M2)_1-y]_uSiO₅:Eu²⁺D, wherein M1 and M2 are at least one of a divalent metal such as Ba, Mg, Ca, and Zn, the values of a, x, y, z and u follow the following relationships: 0.6≦a≦0.85; 0.3≦x≦0.6; 0.85≦y≦1; 1.5≦z≦2.5; 2.6≦u≦3.3; and Eu and D each range from 0.001 to about 0.5. D is an anion selected from the group consisting of F, Cl, Br, S, and N, and at least some of the D anion replaces oxygen in the host silicate lattice of the phosphor. The present yellow phosphors have applications in high brightness white LED illumination systems, LCD display panels, plasma display panels, and yellow LEDs and illumination systems.

An object is to improve luminous efficiency of a light emitting element using triplet exciton energy effectively. Another object is to reduce power consumption of a light emitting element, a light emitting device, and an electronic device. Triplet exciton energy generated in a light emitting layer which exhibits short wavelength fluorescence can be effectively utilized by use of a structure in which the light emitting layers which exhibit short wavelength fluorescence are sandwiched between light emitting layers each including a phosphorescent compound. Further, the emission balance can be improved between the light emitting layer including a phosphorescent compound and the light emitting layer which exhibits fluorescence by the devising of the structure of the light emitting layer which exhibits fluorescence.

Provided is a material for an organic electroluminescence device, which is composed of a compound having a specific structure; and is capable of providing an organic electroluminescence device having a high luminous efficiency, excellent heat resistance, and a long lifetime while having no pixel defects, and an organic electroluminescence device using the same. The organic electroluminescence device comprises an organic thin film layer composed of one or more layers including at least a light-emitting layer and sandwiched between a cathode and an anode. In the organic electroluminescence device, at least one layer of the organic thin film layer comprises the material for an organic electroluminescence device.

An object is to provide an organometallic complex that can emit red light. Another object is to provide an organometallic complex having high emission efficiency. Still another object is to provide an organometallic complex that can emit red light with high luminous efficiency. The present invention provides an organometallic complex having a structure represented by the following general formula (G1′).

In the formula, Ar represents an aryl group having 6 to 25 carbon atoms; R¹ represents any one of hydrogen, an alkyl group having 1 to 4 carbon atoms, and an alkoxy group having 1 to 4 carbon atoms; R² to R⁸ each represent any one of hydrogen, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and a halogen group; at least one of pairs R³ and R⁴, R⁴ and R⁵, and R⁵ and R⁶ may be bound to each other to form a ring; and M represents a central metal of Group 9 elements and Group 10 elements.

Provided are an aromatic amine compound represented by the following Formula (1) and an organic electroluminescent element which has at least one organic thin film layer containing the above aromatic amine derivative in the form of a single component. The organic electroluminescent element described above has a high luminescent efficiency even at a low voltage and a long life. It can emit blue light even at high temperatures. In Formula (1), Ar¹ and Ar² each represent naphthyl and the like; Ar³ to Ar⁶ each represent phenyl, naphthyl, phenanthryl and the like; Ar⁷ to Ar¹⁰ each represent 1,4-phenylene and the like; L represents a single bond and the like; provided that the conditions of (1) and/or (2) are satisfied:

• (1) at least one of Ar³ to Ar⁶ is a condensed aryl group having 10 to 50 nuclear carbon atoms and
• (2) at least one of Ar¹ and Ar² is a condensed aryl group having 12 to 50 nuclear carbon atoms.

A compound represented by Formula 1 below:

(R₁)_a—CB—[Ar]_n—CB—(R₂)_b  <Formula 1>

• • wherein CB denotes carborane, Ar is a substituted or unsubstituted phenylene group, and a detailed description of R₁, R₂, a, b, and n is provided in the detailed description. An organic light-emitting diode including an organic layer including the compound has high luminous efficiency.

An organic light emitting device includes a substrate, an anode and a cathode disposed over the substrate; a luminescent layer disposed between the anode and the cathode wherein the luminescent layer includes a host and at least one dopant; the host of the luminescent layer being selected to include a solid organic material comprising a mixture of at least two components wherein the first component of the mixture is an organic compound that is capable of transporting both electrons and holes and that is substantially non-polar; and the second component of the mixture is an organic compound that is more polar than the first component; and the dopant of the luminescent layer being selected to produce light from the light emitting device.

The organic EL device of the present invention includes a plurality of organic compound-containing layers provided between a cathode and an anode. Of two of the organic compound-containing layers adjacent to each other, one layer positioned nearer the anode has electron mobility lower than that of the other layer positioned nearer the cathode. Accordingly, the organic EL device of the present invention has a high luminous efficiency and a long half-life of the initial luminance.

It is an object to provide an element structure which is suitable for a light-emitting element using a phosphorescent compound. It is another object to provide a light-emitting element with high luminous efficiency by using the element structure. In particular, it is another object to provide a light-emitting element with high luminous efficiency and long life. A light-emitting element is manufactured, which includes a first light-emitting layer and a second light-emitting layer provided to be in contact with each other between a first electrode and a second electrode, where the first light-emitting layer includes a hole transporting host material and a phosphorescent compound, and the second light-emitting layer includes an electron transporting host material and the phosphorescent compound.

It is an object to provide a novel bipolar organic compound. In particular, it is an object to provide a bipolar organic compound excellent in thermal stability. Further, it is another object to provide a bipolar organic compound which is electrochemically stable. A quinoxaline derivative represented by a general formula (1) is provided. Further, since the quinoxaline derivative represented by the general formula (1) is bipolar, the use of the quinoxaline derivative of the present invention allows fabrication of a light-emitting element and a light-emitting device with a low driving voltage and low power consumption. Furthermore, a light-emitting element with high luminous efficiency can be obtained.

The present invention provides a semiconductor light emitting device including a conductive substrate, a first electrode layer, an insulating layer, a second electrode layer, a second semiconductor layer, an active layer, and a first semiconductor layer which are sequentially stacked, wherein an area where the first electrode layer and the first semiconductor layer are in contact with each other is 3 to 13% of an area of the semiconductor light emitting device.

Provided are quantum dots having a gradual composition gradient shell structure which have an improvedluminous efficiency and optical stability, and a method of manufacturing the quantum dots in a short amount of time at low cost. In the method, the quantum dots can be manufactured in a short amount of time at low cost using a reactivity difference between semiconductor precursors, unlike in uneconomical and inefficient conventional methods where shells areformed after forming cores and performing cleaning and redispersion processes. Also, formation of the cores is followed by formation of shells having a composition gradient. Thus, even if the shells are formed to a large thickness, the lattice mismatch between cores and shells is relieved. Furthermore, on the basis of the funneling concept, electrons and holes generated in the shells are transferred to the cores to emit light, thereby obtaining a high luminous efficiency of 80% or more. The quantum dot structure is not limited to Group II-IV semiconductor quantum dots but can be applied to other semiconductors quantum dots, such as Group III-V semiconductors quantum dots and Group IV-IV semiconductors quantum dots. Also, the manufacturing method can be utilized in the development of semiconductor quantum dots having different physical properties, and in various other fields.

An aromatic amine derivative represented by the following formula (1)

• wherein at least one of Ar₁ to Ar₄ is a heterocyclic group represented by the following formula (2) wherein X₁ is an oxygen atom or a sulfur atom.

To provide a light-emitting element having high luminous efficiency and to provide a light-emitting device and an electronic device which consumes low power and is driven at low voltage, a carbazole derivative represented by the general formula (1) is provided. In the formula, α¹, α², α³, and α⁴ each represent an arylene group having less than or equal to 13 carbon atoms; Ar¹ and Ar² each represent an aryl group having less than or equal to 13 carbon atoms; R¹ represents any of a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted phenyl group, and a substituted or unsubstituted biphenyl group; and R² represents any of an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted phenyl group, and a substituted or unsubstituted biphenyl group. In addition, l, m, and n are each independently 0 or 1.

A light source device includes a light emitting diode (LED) device, a lens and a light diffusing layer. The LED device includes an LED chip, which emits light, and a fluorescent, which converts a part of the light from the LED chip. The lens is located on a side of a light emitting face of the LED device. The light diffusing layer is located between the LED device and the lens. An air layer exists between the light diffusing layer and the LED device or between the light diffusing layer and the lens.

Provided are: an aromatic amine derivative in which a terminal substituent such as a dibenzofuran ring or a dibenzothiophene ring is bonded to a nitrogen atom directly or through an arylene group or the like; an organic electroluminescence device including an organic thin film layer formed of one or more layers including a light emitting layer and interposed between a cathode and an anode in which a layer of the organic thin film layer contains the aromatic amine derivative by itself or as a component of a mixture, and the device has a long lifetime and high luminous efficiency; and an aromatic amine derivative for realizing the device.

To provide a long lifetime light-emitting element, in particular, to provide a long lifetime white light-emitting element, and to provide a light-emitting element having high luminous efficiency, in particular, to provide a white light-emitting element having high luminous efficiency. In a light-emitting element having, between an anode and a cathode, a first light-emitting layer containing a first light-emitting substance and a second light-emitting layer containing a second light-emitting substance which is provided to be in contact with the first light-emitting layer, the first light-emitting layer is divided into a layer provided on the anode side and a layer provided on the cathode side. At this time, a host material having a hole-transporting property is used for the layer provided on the anode side, and a host material having an electron-transporting property is used for the layer provided on the cathode side.

Provided is a white LED including a substrate having a reflecting body provided thereon; an LED chip mounted on the substrate; a fluorescence reflecting layer formed on the LED chip; and a phosphor layer formed on the fluorescence reflecting layer and having a higher refractive index than the fluorescence reflecting layer.

An organic light-emitting medium including a diaminopyrene derivative represented by the following formula (1) and an anthracene derivative represented by the following formula (2);

An organic electroluminescence device including opposite anode and cathode, and a hole-transporting region, an emitting layer and an electron-transporting region in sequential order from the anode between the anode and the cathode, wherein the emitting layer is formed of a red emitting layer, a green emitting layer, and blue emitting layer; the blue emitting layer contains a host BH and a fluorescent dopant FBD; the triplet energy E^T_fbd of the fluorescent dopant FBD is larger than the triplet energy E^T_bh of the host BH; the green emitting layer contains a host GH and a phosphorescent dopant PGD; a common electron-transporting layer is provided adjacent to the red emitting layer, the green emitting layer and the blue emitting layer within the electron-transporting region; the triplet energy E^T_el of a material constituting the electron-transporting layer is larger than E^T_bh; and the difference between the affinity of the host GH and the affinity of the material constituting the electron-transporting layer is 0.4 eV or less.

A light source controller is configured to control timings of driving the first and second light sources and the light-source light generator, so that the light-source light of two or more colors generated by the light-source light generator and the light-source light emitted from the second light source are cyclically generated, by setting a light-emitting period of at least one light-source light color having a higher luminous efficiency out of the two or more colors generated by the light-source light generator, shorter than those of the other light-source light colors, and setting a drive power of the first light source during generation of the light-source light color whose light-emitting period is set short, greater than a drive power of the first light source during generation of the other light-source light colors.

A headlamp (1) includes a laser diode (2) for emitting a laser beam and a light-emitting section (5), which contains a fluorescent substance for emitting fluorescence upon receiving the laser beam emitted from the laser diode (2) and diffusing particles (15) for diffusing the laser beam.

White LED device 20 includes LED chip 13 mounted on substrate 1 made of metal, sealing resin 11 that seals LED chip 13; and glass member 12 formed on sealing resin 11. Glass member 12 contains phosphor 22 and thermal conductivity of sealing resin 11 is lower than that of glass member 12.

The light-emitting element includes: a light-emitting layer and a layer for controlling the movement of carriers between a first electrode and a second electrode. The layer for controlling the movement of carriers contains a first organic compound and a second organic compound, and is provided between the light-emitting layer and the second electrode. The first organic compound has an electron transporting property, and the second organic compound has an electron trapping property. The weight percent of the first organic compound is higher than that of the second organic compound. The light-emitting layer emits light when a voltage is applied such that the potential of the first electrode is higher than that of the second electrode. The first organic compound having the electron transporting property may be replaced with an organic compound having a hole transporting property, and the second organic compound having the electron trapping property may be replaced with an organic compound having a hole trapping property.

During the growth of a nitride semiconductor crystal on a nonpolar face nitride substrate, such as an m-face, the gas that constitutes the main flow in the process of heating up to a relatively high temperature range, before growth of the nitride semiconductor layer, (the atmosphere to which the main nitride face of the substrate is exposed) and the gas that constitutes the main flow until growth of first and second nitride semiconductor layers is completed (the atmosphere to which the main nitride face of the substrate is exposed) are primarily those that will not have an etching effect on the nitride, while no Si source is supplied at the beginning of growth of the nitride semiconductor layer. Therefore, nitrogen atoms are not desorbed from near the nitride surface of the epitaxial substrate, thus suppressing the introduction of defects into the epitaxial film. This also makes epitaxial growth possible with a surface morphology of excellent flatness.

A light emitting diode (LED) driving apparatus includes a drive section for driving an LED to emit light, and a control section that controls a driving current supplied from the drive section to the LED. The control section implements luminous power control by controlling an ON/OFF ratio of the driving current if a target value of luminous power of the LED is smaller than a predetermined value. The control section implements luminous power control by controlling a level of the driving current if the target value is equal to or larger than the predetermined value.