4410 results about "Quantum efficiency" patented technology

A polymer light emitting material, wherein the material has a light emitting mechanism based on transition from an excited triplet state to a ground state or transition through an excited triplet state to a ground state of an electron energy level, and the material comprises a nonionic light emitting part which constitutes a part of the polymer or is bound to the polymer. The polymer light emitting material exhibits high light emission efficiency above 5%, which is the limit of external quantum efficiency of fluorescence and can be designed so as to have a large area and hence are suitable for mass production of organic light emitting devices.

Matrixes doped with semiconductor nanocrystals are provided. In certain embodiments, the semiconductor nanocrystals have a size and composition such that they absorb or emit light at particular wavelengths. The nanocrystals can comprise ligands that allow for mixing with various matrix materials, including polymers, such that a minimal portion of light is scattered by the matrixes. The matrixes of the present invention can also be utilized in refractive index matching applications. In other embodiments, semiconductor nanocrystals are embedded within matrixes to form a nanocrystal density gradient, thereby creating an effective refractive index gradient. The matrixes of the present invention can also be used as filters and antireflective coatings on optical devices and as down-converting layers. Processes for producing matrixes comprising semiconductor nanocrystals are also provided. Nanostructures having high quantum efficiency, small size, and / or a narrow size distribution are also described, as are methods of producing indium phosphide nanostructures and core-shell nanostructures with Group II-VI shells.

The present invention provides: an organic EL element exhibiting high luminance, a high external quantum efficiency and a long high temperature driving life at 50° C.; an illuminator and a display device employing the organic EL element; and a material preferably used for the organic EL element.

A high external quantum efficiency is stably secured in a semiconductor light emitting device. At least one recess and / or protruding portion is created on the surface portion of a substrate for scattering or diffracting light generated in a light emitting region. The recess and / or protruding portion has a shape that prevents crystal defects from occurring in semiconductor layers.

A light-emitting element having extremely high efficiency of approximately 25% is provided. The light-emitting element includes a light-emitting layer which contains a phosphorescent guest, an n-type host, and a p-type host, where the light-emitting layer is interposed between an n-type layer including the n-type host and a p-type layer including the p-type host, and where the n-type host and the p-type host are able to form an exciplex in the light-emitting layer. The light-emitting element exhibits an extremely high emission efficiency (power efficiency of 74.3 lm / W, external quantum efficiency of 24.5%, energy efficiency of 19.3%) at a low driving voltage (2.6 V) at which luminance of 1200 cd / m2 is attainable.

OLED devices are disclosed having increased external electroluminescence quantum efficiencies, i.e., increased “out-coupling” efficiencies. OLED devices that have increased out-coupling efficiencies and that are also protected from environmental elements such as moisture and oxygen are also disclosed. The OLED device of the present invention comprises a substrate; an active region positioned on the substrate, wherein the active region comprises an anode layer, a cathode layer and a light-emitting layer disposed between the anode layer and the cathode layer; and a polymeric layer disposed (a) over the active region, (b) under the active region or (c) both over and under the active region. The polymeric layer has microparticles incorporated therein, and the microparticles are effective to increase the out-coupling efficiency of the OLED. In one embodiment, the OLED device comprises a composite barrier layer and the microparticles are incorporated in a polymeric planarizing sublayer of the composite barrier layer. The composite barrier layer in this embodiment also protects the OLED from damage caused by environmental elements such as moisture and / or oxygen.

A light-emitting element having extremely high efficiency of approximately 25% is provided. The light-emitting element includes a light-emitting layer which contains a phosphorescent guest, an n-type host, and a p-type host, where the light-emitting layer is interposed between an n-type layer including the n-type host and a p-type layer including the p-type host, and where the n-type host and the p-type host are able to form an exciplex in the light-emitting layer. The light-emitting element exhibits an extremely high emission efficiency (power efficiency of 74.3 lm / W, external quantum efficiency of 24.5%, energy efficiency of 19.3%) at a low driving voltage (2.6 V) at which luminance of 1200 cd / m2 is attainable.

Matrixes doped with semiconductor nanocrystals are provided. In certain embodiments, the semiconductor nanocrystals have a size and composition such that they absorb or emit light at particular wavelengths. The nanocrystals can comprise ligands that allow for mixing with various matrix materials, including polymers, such that a minimal portion of light is scattered by the matrixes. The matrixes are optionally formed from the ligands. The matrixes of the present invention can also be utilized in refractive index matching applications. In other embodiments, semiconductor nanocrystals are embedded within matrixes to form a nanocrystal density gradient, thereby creating an effective refractive index gradient. The matrixes of the present invention can also be used as filters and antireflective coatings on optical devices and as down-converting layers. Processes for producing matrixes comprising semiconductor nanocrystals are also provided. Nanostructures having high quantum efficiency, small size, and / or a narrow size distribution are also described, as are methods of producing indium phosphide nanostructures and core-shell nanostructures with Group II-VI shells.

A semiconductor sensor, solar cell or emitter or a precursor therefore having a substrate and textured semiconductor layer deposited onto the substrate. The layer can be textured as grown on the substrate or textured by replicating a textured substrate surface. The substrate or first layer is then a template for growing and texturing other semiconductor layers from the device. The textured layers are replicated to the surface from the substrate to enhance light extraction or light absorption. Multiple quantum wells, comprising several barrier and quantum well layers, are deposited as alternating textured layers. The texturing in the region of the quantum well layers greatly enhances internal quantum efficiency if the semiconductor is polar and the quantum wells are grown along the polar direction. This is the case in nitride semiconductors grown along the polar [0001] or [000-1] directions.

The invention discloses a boron-containing efficient organic electroluminescent compound and application of the compound to an OLED device. The structural formula of the compound is as shown in the general formula (1). Boron atom as the core extends outward three six-membered rings composed of carbon-carbon single bonds, wherein the carbon-carbon single bonds also can be replaced with carbon-oxygen and carbon-nitrogen bonds; a benzene ring is sandwiched between each two six-membered rings; and each phenyl ring is respectively externally connected to hydrogen, aryl group, heteroaryl group, alkyl group, alkyloxy group, or arylamine group. The material has good fluorescence quantum efficiency and electroluminescent efficiency, is easy to form an amorphous film, and has good heat stability. Thus, the material can be used as a luminescent layer material in an organic electroluminescent device.

The invention relates to a quantum dot. The quantum dot comprises a core including a semiconductor material Y selected from the group consisting of Si and Ge. The quantum dot also comprises a shell surrounding the core. The quantum dot is substantially defect free such that the quantum dot exhibits photoluminescence with a quantum efficiency that is greater than 10 percent.