68 results about "Metal Nanocrystals" patented technology

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.

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.

Negative active materials including metal nanocrystal composites comprising metal nanocrystals having an average particle diameter of about 20 nm or less and a carbon coating layer are provided. The negative active material includes metal nanocrystals coated by a carbon layer, which decreases the absolute value of the change in volume during charge/discharge and decreases the formation of cracks in the negative active material resulting from a difference in the volume change rate during charge/discharge between metal and carbon. Therefore, high charge/discharge capacities and improved capacity retention capabilities can be obtained.

A method of making a colloidally stable suspension of naked metal nanocrystals includes the steps of: at least partly immersing a metallic sacrificial anode and a cathode into a body of essentially contaminant-free water, the metallic sacrificial anode that includes an essentially contaminant-free metal starting material for making nanocrystals; and applying a voltage potential across the anode and the cathode to form a colloidally stable suspension of naked metal nanocrystals composed essentially of metal from the metallic sacrificial anode.

Metal nanocrystal memories are fabricated to include higher density states, stronger coupling with the channel, and better size scalability, than has been available with semiconductor nanocrystal devices. A self-assembled nanocrystal formation process by rapid thermal annealing of ultra thin metal film deposited on top of gate oxide is integrated with NMOSFET to fabricate such devices. Devices with Au, Ag, and Pt nanocrystals working in the F-N tunneling regime, with hot-carrier injection as the programming mechanism, demonstrate retention times up to 10⁶s, and provide 2-bit-per-cell storage capability.

Provided is a floating gate having multiple charge storing layers, a non-volatile memory device using the same, and a method of fabricating the floating gate and the non-volatile memory device, in which the multiple charge storing layers using metal nano-crystals of nano size is formed to thereby enhance a charge storage capacity of the memory device. The floating gate includes a polymer electrolytic film which is deposited on a tunneling oxide film, and is formed of at least one stage in which at least one thin film is deposited on each stage, and at least one metal nano-crystal film which is self-assembled on the upper surface of each stage of the polymer electrolytic film and on which a number of metal nano-crystals for trapping charges are deposited. The floating gate is made by self-assembling the metal nano-crystals on the polymer electrolytic film, and thus can be fabricated without undergoing a heat treatment process at high temperature.

A memory device having a metal nanocrystal charge storage structure and a method for its manufacture. The memory device may be manufactured by forming a first oxide layer on the semiconductor substrate, then disposing a porous dielectric layer on the oxide layer and disposing a second oxide layer on the porous dielectric layer. A layer of electrically conductive material is formed on the second layer of dielectric material. An etch mask is formed on the electrically conductive material. The electrically conductive material and the underlying dielectric layers are anisotropically etched to form a dielectric structure on which a gate electrode is disposed. A metal layer is formed on the dielectric structure and the gate electrode and treated so that portions of the metal layer diffuse into the porous dielectric layer. Then the metal layer is removed.

A method of producing metallic nanocrystals (107) embedded in high-k dielectric material as well as a nonvolatile flash memory device (100) comprising a discrete charge carrier storage layer, the discrete charge carrier storage layer comprising metallic nanocrystals (107) embedded in high-k dielectric material. In the method described in this invention, firstly an ultra-thin metal film is deposited over a first (105) and a second (106) dielectric layer including high-k dielectric material provided on a substrate (101). Then, the ultra-thin metal film is annealed for forming the metallic nanocrystals (107) on the second dielectric layer (106). Finally, the second dielectric layer (106) and the metallic nanocrystals (107) are covered with a third dielectric layer (108) of high-k dielectric material for forming metallic nanocrystals (107) embedded in high-k dielectric material. The first (105), second (106) and third (108) dielectric layers together with the embedded metallic nanocrystals (107) as the discrete charge carrier storage layer form the nonvolatile flash memory device (100).

Conductive carbon nanotubes (CNTs) obtained by dotting carboxylated CNTs with metal nanocrystals by chemical functional groups, are described, as well as a method for fabricating a pattern or film of the conductive CNTs which involves repeatedly depositing conductive CNTs on a substrate to achieve high surface density. A biosensor is described, in which bioreceptors that bind to target biomolecules are selectively attached to conductive CNTs or a conductive CNT pattern or film. By use of the conductive biosensor, various target biomaterials that bind or react with the bioreceptors can be precisely measured directly or by electrochemical signals at large amounts in one step. Additionally, the biosensor can be used for an electrical detection method capable of providing precise measurement results even with a small amount of source material.

A nanocrystal memory element and a method for fabricating the same are proposed. The fabricating method involves selectively oxidizing polysilicon not disposed beneath and not covered with a plurality of metal nanocrystals, and leaving intact the polysilicon disposed beneath and thereby covered with the plurality of metal nanocrystals, with a view to forming double layered silicon-metal nanocrystals by self-alignment.

The invention relates to a Pd/UiO-66 catalyst having a morphology-controllable Pd metal nanocrystal core and a preparation method and application thereof. The preparation method of the Pd/UiO-66 catalyst comprises S1: dissolving terephthalic acid in dimethyl formamide to obtain a solution A, dissolving a palladium salt in dimethyl formamide to obtain a solution B and dissolving zirconium tetrachloride in dimethyl formamide to obtain a solution C for next use, S2: mixing the solutions A and B, carrying out stirring, mixing the mixture and the solution C and adding a small molecule acid into themixed solution, S3: sealing the mixed solution obtained by the step S2, carrying out heating along with stirring for 20-26h, after the reaction, carrying out centrifugation on the mixed solution andwashing and drying the centrifugal product to obtain the Pd/UiO-66 catalyst having a morphology-controllable Pd metal nanocrystal core. The Pd/UiO-66 catalyst obtained by the one step method has controllable Pd nanocrystal morphology and the morphology-controllable Pd nanoparticle is spherical or tetrahedral. The Pd/UiO-66 catalyst has a good UiO-66 crystalline state and a high specific surface area.

The invention belongs to the technical field of optoelectronic information, and particularly relates to a preparation technique of a nanometer crystal surface graph-strengthened light-emitting composite glass film. The preparation method comprises the following steps: sequentially preparing the glass film containing the light-emitting materials and the graphic film layer containing the metal materials, such as silver, gold or copper, on the glass, single-crystal or polymeric optical substrate surface; enabling the metal ions in the graphic film layer to directionally diffuse into the glass film containing the light-emitting materials and forming the metal (such as silver, gold or copper) nano-crystal in graphical distribution by employing the DC electric field induction thermal transfer printing technique; and improving the fluorescence efficiency of the light-emitting materials by adopting the surface plasma fluorescence enhancement effect of the metal nano-crystal, and further realizing the graphical light-emitting of the glass film. The nano-crystal enhanced graphical light-emitting film prepared based on the technique is applicable to the fields, such as optical information recording, displaying and processing.

A method for manufacturing a memory device having a metal nanocrystal charge storage structure. A substrate is provided and a first layer of dielectric material is grown on the substrate. An absorption layer is formed on the first layer of dielectric material. The absorption layer includes a plurality of titanium atoms bonded to the first layer of dielectric material, a nitrogen atom bonded to each titanium atom, and at least one ligand bonded to the nitrogen atom. The at least one ligand is removed from the nitrogen atoms to form nucleation centers. A metal such as tungsten is bonded to the nucleation centers to form metallic islands. A dielectric material is formed on the nucleation centers and annealed to form a nanocrystal layer. A control oxide is formed over the nanocrystal layer and a gate electrode is formed on the control oxide.

Methods of preparing capped metal nanocrystals are provided. One method includes reacting a metal nanocrystal precursor with a reducing agent in a solution having a platinum catalyst.

The invention relates to a thin film transistor memory and its fabricating method, This memory using the substrate as the gate electrode from bottom to up includes a charge blocking layer, a charge storage layer, a charge tunneling layer, an active region of the device and source/drain electrodes. The charge blocking layer is the ALD grown Al₂O₃ film. The charge storage layer is the two layer metal nanocrystals which include the first layer metal nanocrystals, the insulting layer and the second layer metal nanocrystals grown by ALD method. in sequence from bottom to up. The charge tunneling layer is the symmetrical stack layer which includes the SiO₂/HfO₂/SiO₂ or Al₂O₃/HfO₂/Al₂O₃ film grown. by ALD method in sequence from bottom to up. The active region of the device is the IGZO film grown by the RF sputtering method, and it is formed by the standard lithography and wet etch method. The TFT memory in this invention has the advantage with large P/E window, good data retention, high P/E speed, stable threshold voltage and simple fabricating process.

The disclosure is directed to a set of multi-coordinating imidazole- and zwitterion-based ligands suited for surface-functionalizing quantum dots (QDs). The polymeric ligands are built using a one-step nucleophilic addition reaction between poly(isobutylene-alt-maleic anhydride) and distinct amine-containing functionalities.

The invention discloses a P/N-type laminated resistive random access memory for growing metal nano crystal particles spontaneously. The P/N-type laminated resistive random access memory for growing metal nano crystal particles spontaneously is composed of a lower electrode, an induction layer I, an induction layer II and an upper electrode which are laminated sequentially. The lower electrode is metal which is easy to be oxidized into a metal ion under the forward electric field effect; the induction layer I is an N-type oxide; the induction layer Ii is a P-type oxide; the upper electrode is a metal or electric conducting compound with stable properties under the electric field effect; the lower electrode grows metal nanocrystalline particles spontaneously in the induction layer I under the forward electric field effect, becomes a lower resistor when a reverse bias voltage is added for the lower electrode, thus the operation of data '1' storage is carried out, and becomes a high resistor when a forward or reverse bias voltage is added for the lower electrode, thus the operation of data '0' storage is carried out. The P/N-type laminated resistive random access memory for growing metal nano crystal particles spontaneously provided by the invention has the advantages that the resistive random access memory acts as an induction factor of an electric conducting channel by utilizing metal nanocrystals; and the number of formed nanocrystals is controlled through the induction layer I, so that the vibration of the voltage and current of a device can be controlled effectively and the controllability of the access memory is improved.

Disclosed is a method for preparing an aromatic azoic compound by catalyzing aromatic amine with metal nanocrystals. In the method, the aromatic amine serves as a substrate, the metal nanocrystals serve as catalysts, the substrate, the catalysts and alkali are dissolved in organic solvents in normal-pressure air atmosphere, and the aromatic azoic compound is prepared by means of reaction. The method has the advantages of simplicity and convenience in process, environmental friendliness, catalyst recyclability, high universality of metal catalysts and the like, and avoids the shortcomings that environment-unfriendly metal salt catalysts or oxidants are used in an existing synthetic route, high temperature and high pressure are needed, the catalysts are poor in universality, asymmetric aromatic azoic compound is synthesized by a two-step method and the like. A series of aromatic azoic compounds can be prepared, and the method has a wide industrial application prospect.

The invention discloses icosidodecahedron gold nanocrystal and a controllable preparation method thereof; the icosidodecahedron is composed of 8 low-crystal-face hexagonal sides and 24 high-crystal-face pentagonal sides, and each hexagonal side is provided with 6 pentagonal sides around; the controllable preparation method comprises: subjecting gold chloride (HAuCl4) to direct synthesis by one-step reduction of high-temperature reflux reduction method, with the cationic surfactant diallyldimethylammonium chloride (PDDA) as a protectant and morphological guide agent, and ethylene glycol (EG)/pentanediol (PD) as a solvent and reducing agent. The agents used herein are simple, easy to obtain, and green, the preparation method is simple and efficient and is highly repeatable, the yield of the prepared icosidodecahedron gold nanocrystal is higher than 95%, and the prepared icosidodecahedron gold nanocrystal has regular and unique morphology, good monodispersity and uniformly distributed particle size. The icosidodecahedron gold nanocrystal and the preparation method thereof are of important application value to the mass synthesis of multifaceted gold nanocrystal, and of important guide significance to the controllable synthetic preparation of other polyhedral noble metal nanocrystals.