1207results about "Metal selenides/tellurides" patented technology

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.

A coated nanocrystal capable of light emission includes a substantially monodisperse nanoparticle selected from the group consisting of CdX, where x=S, Se, Te and an overcoating of ZnY, where Y=S, Se, uniformly deposited thereon, said coated nanoparticle characterized in that when irradiated the particles exhibit photoluminescence in a narrow spectral range of no greater than about 60 nm, and most preferably 40 nm, at full width half max (FWHM). The particle size of the nanocrystallite core is in the range of about 20 Å to about 125 Å, with a deviation of less than 10% in the core. The coated nanocrystal exhibits photoluminescence having quantum yields of greater than 30%.

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 low temperature chemical route to efficiently produce nanomaterials is described. The nanomaterials are synthesized by intercalating ions into layered compounds, exfoliating to create individual layers and then sonicating to produce nanotubes, nanorods, nanoscrolls and/or nanosheets. It is applicable to various different layered inorganic compounds (for example, bismuth selenides/tellurides, graphite, and other metal complexes, particularly transition metal dichalcogenides compounds including oxygen, sulfur, tellurium or selenium).

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.

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.

Disclosed herein is a graded core/shell semiconductor nanorod having at least a first segment of a core of a Group II-VI, Group III-V or a Group IV semiconductor, a graded shell overlying the core, wherein the graded shell comprises at least two monolayers, wherein the at least two monolayers each independently comprise a Group II-VI, Group III-V or a Group IV semiconductor.

Nanoparticle compositions of noble metals, and methods of making them, are described. The nanoparticle compositions are made by reacting a salt or complex of a noble metal, such as Au, Ag, Cu or Pt, with a weak ligand, and a reducing agent, in a single liquid phase. The noble metal is typically provided as a halide or carboxylate. The ligand is preferably a fatty acid or aliphatic amine. The reducing agent is preferably a borohydride reagent, hydrazine, or a mixture thereof. Nanocrystals in the size range of 1 nm to 20 nm are produced, and can be made in substantially monodisperse form.

Dendronization of nano-scale surfaces with focal point reactive dendrons to produce stabilized chemically functionalized nano-particles having quantum dot dimensions.

The present invention provides new compositions containing colloidal nanocrystals with high photoluminescence quantum yields, new synthetic methods for the preparation of highly luminescent colloidal nanocrystals, as well as methods to control the photoluminescent properties of colloidal nanocrystals. The new synthetic methods disclosed herein allow photoemission brightness (quantum yield) to be correlated with certain adjustable nanocrystal growth parameters associated with a given synthetic scheme.

An alloyed semiconductor quantum dot comprising an alloy of at least two semiconductors, wherein the quantum dot has a homogeneous composition and is characterized by a band gap energy that is non-linearly related to the molar ratio of the at least two semiconductors; a series of alloyed semiconductor quantum dots related thereto; a concentration-gradient quantum dot comprising an alloy of a first semiconductor and a second semiconductor, wherein the concentration of the first semiconductor gradually increases from the core of the quantum dot to the surface of the quantum dot and the concentration of the second semiconductor gradually decreases from the core of the quantum dot to the surface of the quantum dot; a series of concentration-gradient quantum dots related thereto; in vitro and in vivo methods of use; and methods of producing the alloyed semiconductor and concentration-gradient quantum dots and the series of quantum dots related thereto.

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.

A method is described for the manufacture of semiconductor nanoparticles. Improved yields are obtained by use of a reducing agent or oxygen reaction promoter.

An inorganic nanowire having an organic scaffold substantially removed from the inorganic nanowire, the inorganic nanowire consisting essentially of fused inorganic nanoparticles substantially free of the organic scaffold, and methods of making same. For example, a virus-based scaffold for the synthesis of single crystal ZnS, CdS and free-standing L10 CoPt and FePt nanowires can be used, with the means of modifying substrate specificity through standard biological methods. Peptides can be selected through an evolutionary screening process that exhibit control of composition, size, and phase during nanoparticle nucleation have been expressed on the highly ordered filamentous capsid of the M13 bacteriophage. The incorporation of specific, nucleating peptides into the generic scaffold of the M13 coat structure can provide a viable template for the directed synthesis of a variety of materials including semiconducting and magnetic materials. Removal of the viral template via annealing can promote oriented aggregation-based crystal growth, forming individual crystalline nanowires. The unique ability to interchange substrate specific peptides into the linear self-assembled filamentous construct of the M13 virus introduces a material tunability not seen in previous synthetic routes. Therefore, this system provides a genetic tool kit for growing and organizing nanowires from various materials including semiconducting and magnetic materials.

A method for stabilizing colloidal suspensions of nanocrystals or nanoparticles in a solvent or solid matrix is provided by coating the nanocrystals with bulky organic molecules, specifically dendrons. By coating nanocrystals with a dense organic dendron coat and further cross-linking the dendron ligands, oxidation of the nanocrystals and dissociation of the ligands are avoided. This invention allows nanocrystals to undergo rigorous purification and processing. It may regularly be applied to a variety of nanocrystals.

Disclosed herein is a method of coating nanoparticles with a metal oxide. The method includes substituting surfaces of hydrophobic nanoparticles with an organic substance having a hydrophilic group effective to render the nanoparticles hydrophilic; and injecting the hydrophilic nanoparticles and a precursor of the metal oxide into an organic solvent including an amphiphilic surfactant to coat the nanoparticles with a metal oxide.

A semiconductor nanocrystal composition that is stable and has high luminescent quantum yield. The semiconductor nanocrystal composition has a semiconductor nanocrystal core of a group II alloyed I-III-VI semiconductor nanocrystal material. A method of making a semiconductor nanocrystal composition is also provides which includes synthesizing a semiconductor nanocrystal core of a group II alloyed I-III-VI semiconductor material.

Compounds are expressed by general formula of AxBC2-y where 0<=x<=2 and 0<=y<1, and have CdI2 analogous layer structures; A-site is occupied by at least one element selected from the group consisting of Li, Na, K, Rb, Cs, Mg, Ca, Sr, Ba, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Cd, Hf, Ta, W, Re, Ir, Pt, Au, Sc, rare earth elements containing Y, B, Al, Ga, In, Tl, Sn, Pb and Bi; B-site is occupied by at least one element selected from the group consisting of Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, W, Ir, and Sn; C-site is occupied by at least one element selected from the group consisting of S, Se and Te; the compounds exhibit large figure of merit so as to be preferable for thermoelectric generator/refrigerator.

A coated nano particle and an electronic device using the composite nano particle as an illuminator are provided. The composite nano particle includes a nano particle receiving light and emitting light; and a coating material formed on a surface of the nano particle and having an index of refraction different from that of the nano particle. The coated nano particle is made by coating a surface of the nano particle with a material having an index of refraction, which has an intermediate value between an index of refraction of a matrix and an index of refraction of the nano particle as an illuminator, with a predetermined thickness. The light emitted from the nano particle is efficiently transferred to the outside as the light reflected from the matrix and absorbed by the nano particle is suppressed. Therefore, a luminous efficiency of the illuminator is improved, and an electronic device using the illuminator is provided.

The present invention provides a method of surface passivation of colloidal nanocrystalline materials using a ligand exchange process in which quantum nanoparticles of pre-selected size and shape has polymer multidentate ligands bound at the surface of the nanocrystals for stabilizing quantum size-dependent properties of nanocrystals and providing colloidal stability of the nanoparticles in solvents. The method includes preparing a colloidal dispersion of nanoparticles, preparing a suitable polymer multidentate ligand and dissolving said suitable polymer multidentate ligand in a fluid, the polymer multidentate ligand having first portions which can bind to a surface of the nanoparticles and a second portion which does not bind to the surface of the nanoparticles, and mixing the fluid containing the suitable polymer with the colloidal dispersion of nanoparticles under conditions suitable to induce binding of at least some of the first portions of the polymer multidentate ligand onto the surface of the nanoparticles, the suitable polymer multidentate ligand being selected so that the at least some of the first portions which bind to the surface to stabilize quantum size-dependent properties of the nanocrystals, and the second portion which does not bind to the surface provides colloidal stability of the nanoparticles in a desired fluid.

The invention relates to methods for preparing 3-element semiconductor nanocrystals of the formula WY_xZ_(1-x), wherein W is a Group II element, Y and Z are different Group VI elements, and 0<X<1, comprising dissolving a Group II element, a first Group VI element, and a second Group VI element in a one or more solvents. The Group II, VI and VI elements are combined to provide a II:VI:VI SCN precursor solution, which is heated to a temperature sufficient to produce semiconductor nanocrystals of the formula WY_xZ_(1-x). The solvent used to dissolve the Group II element comprises octadecene and a fatty acid. The solvent used to dissolve the Group VI elements comprises octadecene. The invention also includes semiconductor nanocrystals prepared according to the disclosed methods, as well as methods of using the semiconductor nanocrystals.

Disclosed herein are a core/shell nanocrystal and a method for producing the same. More specifically, disclosed herein are a core/shell nanocrystal comprising a metal-doped shell nanocrystal, and a method for producing the same. The core/shell nanocrystal comprises a core nanocrystal and a metal-doped shell nanocrystal formed on the core nanocrystal. Based on the structure, the core/shell nanocrystal exhibits superior crystallinity and high luminescence efficiency, enables easy control of the shape and size and can be produced in a simple manner.

Systems and methods may provide electrical contacts to an array of substantially vertically aligned nanorods. The nanorod array may be fabricated on top of a conducting layer that serves as a bottom contact to the nanorods. A top metal contact may be applied to a plurality of nanorods of the nanorod array. The contacts may allow I/V (current/voltage) characteristics of the nanorods to be measured.