1391results about How to "Improve external quantum efficiency" patented technology

The present invention generally relates to organic photosensitive optoelectronic devices. More specifically, it is directed to organic photovoltaic devices, e.g., organic solar cells. Further, it is directed to an optimized organic solar cell comprising multiple stacked subcells in series. High power conversion efficiency are achieved by fabrication of a photovoltaic cell comprising multiple stacked subcells with thickness optimization and employing an electron blocking layer.

Disclosed is an organic electroluminescent device having high emission luminance, high external quantum efficiency and long lifetime. Also disclosed are a display and an illuminating device. The organic electroluminescent device is characterized in that it comprises, between a pair of electrodes, a constituent layer including at least a phosphorescence emission layer, wherein at least one in the constituent layer contains a compound represented by formula (1),

Organic photosensitive optoelectronic devices are disclosed. The devises comprise photoconductive organic thin films in a heterostructure, which include an exciton blocking layer to enhance device efficiency. The use of fullerenes in the electron conducting layer has lead to devices with high efficiency. Single heterostructure, stacked and wave-guide type embodiments are disclosed. Devices having multilayer structures and an exciton blocking layer are also disclosed. Guidelines for selection of exciton blocking layers are provided.

The present invention generally relates to organic photosensitive optoelectronic devices. More specifically, it is directed to organic photovoltaic devices, e.g., organic solar cells. Further, it is directed to an optimized organic solar cell comprising multiple stacked subcells in series. High power conversion efficiency are achieved by fabrication of a photovoltaic cell comprising multiple stacked subcells with thickness optimization and employing an electron blocking layer.

An organic electroluminescent device having a pair of electrodes and at least one organic layer including a light-emitting layer interposed between the pair of electrodes, in which the organic layer contains at least one compound represented by formula (I): wherein Z1 and Z2 each independently represent a nitrogen-containing heterocycle coordinated with the platinum through a nitrogen atom; Q1 and Q2 each independently represent a group bonded with the platinum through a carbon atom, an oxygen atom, a sulfur atom, a nitrogen atom or a phosphorous atom; Q1 and Q2 each represent a structure different from each other; L1 and L2 each independently represent a single bond or a linking group; and n represents 0 or 1.

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.

A method of growing an AlGaN semiconductor material utilizes an excess of Ga above the stoichiometric amount typically used. The excess Ga results in the formation of band structure potential fluctuations that improve the efficiency of radiative recombination and increase light generation of optoelectronic devices, in particular ultraviolet light emitting diodes, made using the method. Several improvements in UV LED design and performance are also provided for use together with the excess Ga growth method. Devices made with the method can be used for water purification, surface sterilization, communications, and data storage and retrieval.

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.

A method for designing semiconductor light emitting devices is disclosed wherein the side surfaces (surfaces not parallel to the epitaxial layers) are formed at preferred angles relative to vertical (normal to the plane of the light-emitting active layer) to improve light extraction efficiency and increase total light output efficiency. Device designs are chosen to improve efficiency without resorting to excessive active area-yield loss due to shaping. As such, these designs are suitable for low-cost, high-volume manufacturing of semiconductor light-emitting devices with improved characteristics.

An organic EL device (1) comprises: a light-transmissive substrate (2); a transparent electrode (4); an organic emitting layer (5); and an opposing electrode (6). A light-extraction layer (3) provided by layering a high refractive index layer (31) adjoining the transparent electrode (4) and a low refractive index layer (32) adjoining the light-transmissive substrate (2) includes recess-protrusion units (31A) each provided by a protrusion (311) and a recess (312) at an interface between the high refractive index layer (31) and the low refractive index layer (32). In at least one of the recess-protrusion units (31A), a distance d1 from the interface between the high refractive index layer (31) and the low refractive index layer (32) to an interface between the transparent electrode (4) and the high refractive index layer (31) is equal to or more than an optical coherence length and a height d2 of the protrusion (311), a width d3 of the protrusion (311) and a gap d4 between the protrusion (311) and another protrusion (311) adjoining the protrusion across the recess (312) is 1 μm or more.

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.

An organic electroluminescent device having a pair of electrodes and at least one organic layer including a light-emitting layer interposed between the pair of electrodes, in which the organic layer contains at least one compound represented by formula (I):wherein Z1 and Z2 each independently represent a nitrogen-containing heterocycle coordinated with the platinum through a nitrogen atom; Q1 and Q2 each independently represent a group bonded with the platinum through a carbon atom, an oxygen atom, a sulfur atom, a nitrogen atom or a phosphorous atom; Q1 and Q2 each represent a structure different from each other; L1 and L2 each independently represent a single bond or a linking group; and n represents 0 or 1.

Organic photosensitive optoelectronic devices are disclosed. The devises are thin-film crystalline organic optoelectronic devices capable of generating a voltage when exposed to light, and prepared by a method including the steps of: depositing a first organic layer over a first electrode; depositing a second organic layer over the first organic layer; depositing a confining layer over the second organic layer to form a stack; annealing the stack; and finally depositing a second electrode over the second organic layer.

This is a process method for a high brightness LED chip applying nature light etching and ICP dry etching technology to the transparent conducting film on traditional and vertical LED on GaN base to increase illumination efficiency.

The back surface of a semiconductor crystal substrate 102 which has a thickness of about 150 μm and is made of undoped GaN bulk crystal consists of a polished plane 102a which is flattened through dry-etching and a grinded plane 102b which is formed in a taper shape and is flattened through dry-etching. On about 10 nm in thickness of GaN n-type clad layer (low carrier concentration layer) 104, about 2 nm in thickness of Al0.005In0.045Ga0.95N well layer 51 and about 18 nm in thickness of Al0.12Ga0.88N barrier layer 52 are deposited alternately as an active layer 105 which emits ultraviolet light and has MQW structure comprising 5 layers in total. Before forming a negative electrode (n-electrode c) on the polished plane of the semiconductor substrate a, the polished plane is dry-etched.

A light emitting diode (LED) structure includes a substrate with a surface and cylindrical photonic crystals, a first type doping semiconductor layer, a first electrode, a light emitting layer, a second type doping semiconductor layer and a second electrode. The first type doping semiconductor layer is formed on the substrate to cover the photonic crystals. The light emitting layer, the second type doping semiconductor layer and the second electrode are sequentially formed on a portion of the first type doping semiconductor layer. The first electrode is formed on the other portion of the first type doping semiconductor layer without being covered by the light emitting layer. Because the substrate with photonic crystals can improve the epitaxial quality of the first type doping semiconductor layer and increase the energy of the light forwardly emitting out of the LED, the light emitting efficiency of the LED is effectively enhanced.

A nitride-based light-emitting diode is provided, including a substrate having a light extraction layer grown on the substrate, and a nitride semiconductor epitaxy layer grown on the light extraction layer. The external quantum efficiency is improved by changing the traveling path of the emitted light and by matching the refraction index between the light extraction layer and the substrate. Also, a high power nitride-based light-emitting diode having a sacrificial layer is disclosed. A sacrificial layer is used for growing a light-emitting structure, and a binding layer made of two or more metals or alloys is used to bind the grown light-emitting structure and a substrate with high thermoconductivity. The sacrificial layer is later entirely etched away with a chemical solution used in a chemical etching process, and the nitrogen epitaxy structure is placed on the substrate with high thermoconductivity so that the diode can operate at high electrical current to improve external quantum efficiency.

Disclosed are a semiconductor device and method of manufacturing the same comprising a substrate, a mesa region adjacent to the substrate, an electroplated metal layer, for reducing the thermal resistance of the device, surrounding the mesa region, an insulator layer separating a side portion of the mesa region from the electroplated metal layer, a heat sink, a bonding layer adjacent to the heat sink, and a second metal layer in between the substrate and the heat sink, wherein the substrate is adjacent to the bonding layer, and wherein the electroplated metal layer dimensioned and configured to have a thickness of at least half a thickness of the mesa region; and to laterally spread heat away from the mesa region. The mesa region comprises a first cladding layer adjacent to the substrate, an active region adjacent the first cladding layer, and a second cladding layer adjacent to the active region.

The addition of a highly polarizable additive such as an organic anionic surfactant to an electrically active polymer improves the electrical properties of the polymer. When such an additive is added to an electroluminescent organic polymer this mixture can be used in diodes having an anode contacting a layer of this mixture as the active light-emitting layer and an air-stable metal cathode having a work function larger than 4 eV. The external efficiency and brightness versus voltage are significantly improved compared to results obtained with the same electroluminescent polymer used alone with high work function (>4.0 eV) metal cathodes. Specifically, device performance with indium / tin-oxide (ITO) as the anode, poly(2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene), MEH-PPV, as the electroluminescent polymer, lithium nonylphenoxy ether sulfate as the surfactant additive and aluminum as the cathode is comparable to or better than that obtained with high performance devices using calcium as the cathode.

A surface treated nitride semiconductor in use for a light emitting diode, in which an n-cladding layer is formed on a substrate. An active layer having a multiple quantum well structure is formed on the n-cladding layer. A p-cladding layer is formed on the active layer. A p-capping layer is formed on the p-cladding layer in a low temperature range in which single crystal growth does not take place. The p-capping layer has a nanoscale roughened structure formed in an upper surface thereof via heat treatment in a high temperature range in which at least partial crystallization takes place. The nanoscale roughened structure reduces total internal reflection of the nitride semiconductor thereby improving external quantum efficiency thereof.

The present invention relates to a III-nitride semiconductor light-emitting device having high external quantum efficiency, provides a III-nitride compound semiconductor light-emitting device including an active layer generating light by recombination of electrons and holes and containing gallium and nitrogen, an n-type Al(x)ln(y)Ga(1-x-y)N layer epitaxially grown before the active layer is grown, and an n-type electrode electrically contacting with the n-type Al(x)ln(y)Ga(1-x-y)N layer, in which the n-type Al(x)ln(y)Ga(1-x-y)N layer has a surface which is exposed by etching and includes a region for scribing and breaking the device and a region for contact with the n-type electrode, and the surface of the region for scribing and breaking the device is roughened, thereby it is possible to increase external quantum efficiency of the light-emitting device.

A light emitting diode device emitting at a wavelength of 390-415 nm has a bulk gallium and nitrogen containing substrate with an active region. The device has a current density of greater than about 175 Amps / cm2 and an external quantum efficiency with a roll off of less than about 5% absolute efficiency.

Projections / depressions of a two-dimensional periodic structure are formed in a p-GaN layer (4) such that the period of the projections / depressions is 1 to 20 times the wavelength of light radiated from an active layer (3) in a semiconductor. As a result, a diffractive effect achieved by the projections / depressions of the two-dimensional periodic structure change the direction in which the light radiated from the active layer (3) travels. If the projections / depressions are not provided, light at a radiation angle which satisfies conditions for total reflection at the interface between a semiconductor device and an air cannot be extracted to the outside of the semiconductor device so that the light emission efficiency of the device is low. By contrast, the projections / depressions as formed with a period according to the present invention diffract the light at an angle which does not cause total reflection so that the efficiency with which the light is extracted to the outside of the semiconductor device is improved exponentially. This improves the light emission efficiency of the device.

An organic electroluminescent device. The device has an organic electroluminescent light recovery layer consisting of dielectric material and nanoscale metal particles or organic material and nanoscale metal particles. The membrane of the organic electroluminescent light recovery layer cross couples with surface plasmon resonance and recovers light trapped in the device, enhancing the light emission efficiency of the organic electroluminescent device.

An LED chip (2) emitting blue light is mounted on an insulating substrate (1) at both ends of which electrode films (11, 12) are formed, and a pair of electrodes of the LED chip (2) is electrically connected to the pair of electrode films (11, 12) respectively by connection means (3). On the LED chip (2), there are provided a first resin layer (4) made of resin containing a red color conversion member (4a) for converting blue light into red light and provided so as to coat substantially half of the LED chip (2) and to be in close contact with the LED chip (2), and a second resin layer (5) made of resin containing a green color conversion member (5a) for converting blue light into green light and provided so as to coat similarly the other substantially half of the LED chip (2). As a result, it is possible to attach the resin containing light color conversion members directly to the LED chip in such manner that the red and green light color conversion members are not mixed with each other and obtain a white semiconductor light emitting device having high external quantum efficiency.

Disclosed is an organic electroluminescent element which is characterized in that constituent layers including at least a phosphorescent light-emitting layer are provided between a pair of electrodes, and at least one of the constituent layers contains a compound represented by general formula (1). (In the formula, A1, A2 and A3 each represents a substituent; n1 and n2 each represents an integer of 0-3; X1 and X2 each represents an oxygen atom, a sulfur atom, an alkylene group, an imino group, a carbonyl group, a sulfoxide group or a sulfonyl group, or alternatively X2 represents a bonding hand; and Z1, Z2, Z3 and Z4 each represents an optionally substituted aromatic heterocyclic ring or an aromatic hydrocarbon ring, provided that all of the Z1, Z2, Z3 and Z4 are not aromatic hydrocarbon rings at the same time.)

A color conversion member of a high efficiency achieved by restraining fluorescence emitted from a certain phosphor from being absorbed again by another different phosphor, as well as a light emitting apparatus including the color conversion member are provided. The color conversion member includes N light transmissive members each containing a different one of N different phosphors illuminated with excitation light to emit fluorescence in a visible wavelength region, and the N light transmissive members are stacked in order (N is a natural number of not less than two). The color conversion member is designed in such a manner that the refractive index increases in the thickness direction while the fluorescence wavelength decreases in the thickness direction.

The present invention discloses a semiconductor light emitting device including an active layer for generating light by recombination of electron and hole between a first semiconductor layer having first conductivity and a second semiconductor layer having second conductivity different from the first conductivity, the second semiconductor layer being disposed on the active layer. The semiconductor light emitting device comprises first array including a trench having a first inclination angle, and second array including a trench having a second inclination angle different from the first inclination angle.