417 results about "Semiconductor nanocrystals" patented technology

Nanocomposite photovoltaic devices are provided that generally include semiconductor nanocrystals as at least a portion of a photoactive layer. Photovoltaic devices and other layered devices that comprise core-shell nanostructures and/or two populations of nanostructures, where the nanostructures are not necessarily part of a nanocomposite, are also features of the invention. Varied architectures for such devices are also provided including flexible and rigid architectures, planar and non-planar architectures and the like, as are systems incorporating such devices, and methods and systems for fabricating such devices. Compositions comprising two populations of nanostructures of different materials are also a feature of the invention.

A water soluble semiconductor nanocrystal capable of light emission is provided, including a quantum dot having a selected band gap energy, a layer overcoating the quantum dot, the overcoating layer comprised of a material having a band gap energy greater than that of the quantum dot, and an organic outer layer, the organic layer comprising a compound having a least one linking group for attachment of the compound to the overcoating layer and at least one hydrophilic group space apart from the linking group by a hydrophobic region sufficient to prevent electron charge transfer across the hydrophobic region. The particle size of the nanocrystal core is in the range of about 12.ANG. to about 150.ANG., with a deviation of less than 10% in the core. The coated nanocrystal exhibits photoluminescende having quantum yield of greater than 10% in water.

A nanostructured composite material comprising semiconductor nanocrystals in a crystalline semiconductor matrix. Suitable nanocrystals include silicon, germanium, and silicon-germanium alloys, and lead salts such as PbS, PbSe, and PbTe. Suitable crystalline semiconductor matrix materials include Si and silicon-germanium alloys. A process for making the nanostructured composite materials. Devices comprising nanostructured composite materials.

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.

A multicolor electronic display is based on an array of luminescent semiconductor nanocrystals. Nanocrystals which emit light of different colors are grouped into pixels. The nanocrystals are optically pumped to produce a multicolor display. Different sized nanocrystals are used to produce the different colors. A variety of pixel addressing systems can be used.

Nanocomposite photovoltaic devices are provided that generally include semiconductor nanocrystals as at least a portion of a photoactive layer. Photovoltaic devices and other layered devices that comprise core-shell nanostructures and/or two populations of nanostructures, where the nanostructures are not necessarily part of a nanocomposite, are also provided, as are devices including a recombination material and/or multiple electrodes. Varied architectures for such devices are also provided, including flexible and rigid architectures, planar and non-planar architectures, and the like, as are systems incorporating such devices, and methods and systems for fabricating such devices. Compositions comprising two populations of nanostructures of different materials or nanostructures and a small molecule are also described, as are doped polymer nanocomposites. Compositions useful for making nanocomposites are also described.

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 method of synthesizing colloidal nanocrystals is disclosed using metal oxides or metal salts as a precursor. The metal oxides or metal salts are combined with a ligand and then heated in combination with a coordinating solvent. Upon heating, the metal oxides or salts are converted to stable soluble metal complexes. The metal complexes are formed by cationic species combining with the ligands and/or with the coordinating solvent. Finally, an elemental chalcogenic precursor, for example, Se, Te, or S, is introduced into the soluble metal complex to complete the formation of the nanocrystals at a controllable rate. High-quality CdSe, CdTe, and CdS nanocrystals are produced when CdO is used as the cadmium precursor. With the present method, the size, size distribution, and shape (dots or rods) of the resulting nanocrystals can be controlled during growth. For example, the resulting nanocrystals are nearly monodisperse without any size separation. Further, the method represents a major step towards a green chemistry approach for synthesizing high-quality semiconductor nanocrystals.

Disclosed are a white light-emitting diode (LED) in which an emission layer comprising a red luminous body and a green luminous body is formed on a blue LED, and a preparation method thereof. The emission layer comprises both of at least one inorganic phosphor and at least one semiconductor nanocrystal. The white LED prepared according to the present invention has excellent color purity, high luminous efficiency and improved light stability so that it can be advantageously used as a light source for various display devices.

Provided is a chemical wet preparation method for Group 12-16 compound semiconductor nanocrystals. The method includes mixing one or more Group 12 metals or Group 12 precursors with a dispersing agent and a solvent followed by heating to obtain a Group 12 metal precursor solution; dissolving one or more Group 16 elements or Group 16 precursors in a coordinating solvent to obtain a Group 16 element precursor solution; and mixing the Group 12 metal precursors solution and the Group 16 element precursors solution to form a mixture, and then reacting the mixture to grow the semiconductor nanocrystals. The Group 12-16 compound semiconductor nanocrystals are stable and have high quantum efficiency and uniform sizes and shapes.

The present invention relates to a light-emitting device including a light source, a first light-emitting material spaced apart from the light source, and at least one additional light-emitting material. The first light-emitting material includes low reabsorbing semiconductor nanocrystals having an emission-center core, an exterior protective shell, and at least one inner light-absorbing shell. The device is useful for efficiently producing white light having a high color rendering index.

Light-emitting devices are provided that incorporate one or more underlying LED chips or other light sources and a layer having one or more populations of nanoparticles disposed over the light source. The nanoparticles may absorb some light emitted by the underlying source, and re-emit light at a different level. By varying the type and relative concentration of nanoparticles, different emission spectra may be achieved. White light and specialty-color emission may be achieved. Devices also may include multiple LED chips, with nanoparticles disposed over one or more underlying chips in an array.

A white light-emitting organic-inorganic hybrid electroluminescence device which has nanocrystals as illuminants. According to the device, a semiconductor nanocrystal layer composed of at least one kind of nanocrystals, a hole transport layer and/or an electron transport layer simultaneously emit light to produce white light, or a semiconductor nanocrystal layer composed of at least two kinds of nanocrystals emits light at different wavelengths to produce white light. The device can be used as a backlight unit for a liquid crystal display, or can be used to manufacture an illuminator.

A solar cell includes a semiconductor base layer, a semiconductor nanocrystal complex over the semiconductor base layer, and a semiconductor emitter layer formed over the semiconductor nanocrystal complex. The semiconductor nanocrystal complex includes nanocrystal cores dispersed in an inorganic matrix material. A corresponding method is also disclosed.

An hyperspectral imaging device comprising semiconductor nanocrystals is provided.

The invention comprises a composite material comprising a host material in which are incorporated semiconductor nanocrystals. The host material is light-transmissive and/or light-emissive and is electrical chargetransporting thus permitting electrical charge transport to the core of the nanocrystals. The semiconductor nanocrystals emit and/or absorb light in the near infrared spectral range. The nanocrystals cause the composite material to emit/absorb energy in the near infrared (NIR) spectral range, and/or to have a modified dielectric constant, compared to the host material. The invention further comprises electro-optical devices composed of this composite material and a method of producing them. Specifically described are light emitting diodes that emit light in the NIR and photodetectors that absorb light in the same region.

A method for preparing water-stable semiconductor nanocrystal complexes that can be stably coupled to tertiary molecules using a self-assembled coating of diblock polymers. The diblock polymers have hydrophilic ends containing hydrophilic functional groups and hydrophobic ends containing hydrophobic functional groups. The diblock polymers are assembled around a semiconductor nanocrystal having a lyophilic surface outer layer. The diblock polymers are further crosslinked via bridging molecules that link adjacent diblock polymers through the hydrophilic functional groups of the hydrophilic ends of the diblock polymers to form a semiconductor nanocrystal complex. The functional groups present on the outer surface of the amphiphilic diblock polymer may serve as attachment sites for coupling tertiary molecules to the semiconductor nanocrystal complex.

A micronized semiconductor nanocrystal complex including a plurality of semiconductor nanocrystals embedded in a first matrix material wherein the first matrix material is a micronized polymer. The micronized semiconductor nanocrystal complex can be used in or include inks, paints, dyes, LEDs, taggants, tracers and cosmetics. The present application further provides methods of making micronized semiconductor nanocrystal complexes.

The present invention is directed to photostable sunscreen and/or artificial tanning compositions including quantum dot nanocrystals of a material selected from semiconductor nanocrystals, modified semiconductor nanocrystals, multicomponent semiconductor/semiconductor nanocrystals, and hybrid semiconductor/metal nanocrystals, the quantum dot nanocrystals having an absorption band gap occurring at wavelengths higher than 400 nm whereby the quantum dot nanocrystals have substantial broadband absorption properties of ultraviolet light at wavelengths across the range of both UV-A (320-400 nm) and UV-B (280-320 nm), and a dermatologically acceptable carrier for the quantum dot nanocrystals. The present invention is further directed to photostable sunscreen and/or artificial tanning compositions including a material selected from metallic nanocrystals, multicomponent metal/metal nanocrystals, and alloyed metal nanocrystals, the metallic material having a surface plasmon resonance occurring sufficiently into the visible or infrared spectral region whereby broad absorption features due to electronic transitions, the broad absorption features located at higher energies, provide substantial broadband absorption properties of ultraviolet light at wavelengths across the range of both UV-A (320-400 nm) and UV-B (280-320 nm), and a dermatologically acceptable carrier for the metallic material.

A white light light emitting diode (LED) formed by depositing an LED chip that emits light at a first wavelength and forming a semiconductor nanocrystal complex. The semiconductor nanocrystal complex absorbs at least a portion of the light emitted by the LED chip and emits light at a second wavelength. The semiconductor nanocrystal complex and a powdered phosphor are deposited over the LED chip. The powdered phosphor also absorbs a portion of the light emitted by the LED chip and emits light at a third wavelength. The semiconductor nanocrystal complex is selected to provide a color of the spectrum that is lacking from the combined output of phosphor/LED chip combination, to improve a Color Rating Index (CRI) value and to provide a “warmer” light. The semiconductor nanocrystal complex and the powdered phosphor can be mixed into the same matrix material or into separate matrix materials and/or deposited as separate layers.

The present invention provides a core/multishell semiconductor nanocrystal comprising a core and multiple shells, which exhibits a type-I band offset and high photoluminescence quantum yield providing bright tunable emission covering the visible range from about 400 nm to NIR over 1600 nm.

A color converting material composition including: a light-transmissible matrix; a fluorescent semiconductor nanocrystal which absorbs at least light in a first wavelength region; and an organic fluorescent dye which absorbs at least light in a second wavelength region.