17 results about "Silicon nanocrystal" patented technology

The invention relates to the technical field of brake discs, in particular to a carbon-ceramic brake disc with a composite functional layer and a preparation method of the carbon-ceramic brake disc. The problems that a brake disc is insufficient in strength and poor in ablation resistance are solved. The preparation method comprises the following steps: carrying out low-temperature plasma treatment and silicon dioxide sol impregnation on carbon fibers, and inserting a graphene oxide film between woven layers, so as to obtain a carbon fiber preform; primary densification is carried out through pretreatment activation, low-temperature permeation and high-temperature permeation, and two graphitization treatments are combined; siliconizing is carried out through low-pressure permeation, high-pressure strengthening and laser cladding, and secondary densification is carried out through precursor impregnation and cracking; the titanium zirconium silicide-nano aluminum oxide composite layer generated through the embedding process forms a compact oxidation film at high temperature, and the silicon carbide nano crystal whiskers are subjected to chemical vapor deposition, so that the strength and ablation resistance of the prepared carbon ceramic brake disc are improved.

A silicon-based phase / metal phase compounded silicon-based composite material. A silicon-based phase is formed by assembling silicon-based nanocrystals, the outer surface of the silicon-based phase is coated with metal phases, and the metal phases are mutually connected to form a body-shaped network structure; the silicon-based phase comprises a single silicon phase or an Si-Ge composite phase; when the single silicon phase is selected as the silicon-based phase, the silicon-based nanocrystals are selected from silicon nanocrystals; when the Si-Ge composite phase is selected as the silicon-based phase, the silicon-based nanocrystals are selected from Si-Ge nanocrystals; and the melting point of the metal phases is lower than that of the silicon-based phase. A lithium-ion battery assembled by using the silicon-based composite material as a negative electrode has extremely good rate capability and cycling stability, and also has a high initial capacity and high initial efficiency.

The present invention belongs to the field of optical communications technology, specifically a high-brightness, communication-band silicon-based luminescent film doped with a high concentration of erbium and a method for preparing the same. The present invention uses HSQ as a solvent and erbium nitrate pentahydrate as a source of erbium. Ytterbium ions and independent silicon quantum dots are co-doped, stirred, spin-coated, and subjected to high-temperature annealing to obtain a high-brightness erbium-doped silicon-based luminescent film. HSQ photoresist is used as a precursor material for the preparation of silicon nanocrystal films. After being doped with erbium and subjected to high-temperature annealing, the resulting film contains a large amount of silicon nanocrystals. The silicon nanocrystals act as sensitizers in the energy transfer process, absorbing incident photon energy and then transferring and activating erbium ions to achieve photoluminescence with a central emission wavelength of 1.54 μm. The present invention avoids the numerous defects associated with ion implantation and eliminates the need for maintaining a high vacuum. The resulting erbium-doped film has a high concentration of silicon nanocrystals, which act as erbium luminescence sensitizers, and is simple to prepare and safe to operate.

The invention discloses a high-binding-force ceramic coating special for an etching pot and a layered coating method of the high-binding-force ceramic coating, and particularly relates to the field of chemical engineering and material synthesis. The coating is composed of a bottom layer and a surface layer, the bottom layer forms a three-dimensional network through crosslinking of a modified silane compound, an organosilicon-polyimide block copolymer, nano polyurethane microspheres and superfine silicon carbide powder, and strong chemical bonding is formed by carboxyl at the tail end of the three-dimensional network and a metal base material. The surface layer comprises a nano boron nitride sheet layer and a three-dimensional heat-conducting network constructed by silicon nanowhiskers, and a ceramic base material, nano silver, pH response type modified hydroxyapatite and a SiO2 coating layer are embedded into the surface layer. The coating method comprises the steps of substrate etching, respective preparation of the bottom layer coating and the surface layer coating, layered spraying and gradient curing. According to the invention, high binding force and excellent thermal conductivity of the coating and the base material are realized, and the durability and reliability of the etching pot under the condition of rapid change of temperature difference are remarkably improved.

The application relates to the technical field of battery negative electrode materials, in particular to a negative electrode material, a preparation method thereof, a lithium ion battery and an electric equipment. The negative electrode material comprises silicon-based negative electrode material particles, a titanium oxide layer arranged on the surface of the silicon-based negative electrode material particles, and a carbon coating layer arranged on the surface of the titanium oxide layer; the silicon-based negative electrode material particles contain silicon nanocrystal domains, and the average particle size of the silicon nanocrystal domains is less than or equal to 10 nm. The size of the silicon nanocrystal domains in the negative electrode material is small, the titanium oxide layer and the carbon layer can better inhibit the volume expansion of the negative electrode material and improve the transmission capacity of lithium ions, so that the electrochemical performance of the negative electrode material is improved.

The invention discloses a near-infrared light-emitting silicon nanocrystal-silicon oxide composite material as well as preparation and application thereof. The material consists of silicon oxide and silicon nanocrystal particles which are uniformly distributed and have spherical structures, the silicon nanocrystal particles have crystal lattice fringes of monocrystalline silicon, the size of the silicon oxide with the spherical structure is 100 nm, the average size of the silicon nanocrystal particles is 13.71 nm, and the size of the crystal lattice fringes is 0.31 nm. According to the invention, the problems of unstable performance, complicated synthesis process and high cost of the existing silicon nanocrystal are solved. The silicon nanocrystals in the prepared composite material uniformly grow in the silicon oxide and on the surface of the silicon oxide, and the composite material can stably realize 600-1100 nm near-infrared emission under the excitation of 365 nm ultraviolet light, and meets the application requirements of near-infrared conversion type light emitting diodes.

The present invention provides an ultraviolet shielding agent containing spherical silicon nanocrystals of a predetermined particle size. The agent contains spherical silicon nanocrystals with a peak particle size distribution between 40 nm and 200 nm. Particularly, it is preferable to include silicon nanocrystals between 60 nm and less than 90 nm. The agent has an ultraviolet transmittance of 10% or less at 400 nm and below, a visible light transmittance of 50% or more at 500 nm and above, and a haze value of 40% or more at 500 nm and below. The ultraviolet shielding agent is in the form of a dispersion or film containing silicon nanocrystals with a controlled particle size distribution.

The invention relates to a bulk phase silicon nanocrystal-based high-performance composite negative electrode material and preparation and application thereof, and the preparation method of the negative electrode material comprises the following steps: (1) weighing silicon monoxide powder, a lithium source additive and a heat conduction network material, grinding and mixing to obtain a precursor mixture; and (2) placing the precursor mixture on a carrier, carrying out high-temperature disproportionation reaction, and cooling to room temperature to obtain modified silicon monoxide composite powder, namely a target product. Compared with the prior art, the preparation method has the advantages that the mechanical stress caused by volume expansion of the nanocrystals in the circulation process can be effectively relieved, and particle breakage is avoided, so that the circulation stability and the like of the material are remarkably improved.

The invention relates to the technical field of photovoltaic cell manufacturing, and discloses a method for preparing a TBC cell by using silicon ink and the TBC cell, S1, providing a silicon substrate, and preparing a tunneling oxide layer on the back surface of the silicon substrate; s2, printing a preset first interdigitated graph and a preset second interdigitated graph on the tunneling oxide layer by using hydrogen-rich silicon ink; the hydrogen-rich silicon ink comprises a silicon nanocrystal and a hydrogen-rich carrier; and S3, carrying out in-situ collaborative sintering on the printed hydrogen-rich silicon ink by adopting a pulse energy source. Through in-situ hydrogenation repair, high-temperature furnace annealing which causes hydrogen loss is abandoned, and by utilizing the synergistic effect of laser and hydrogen-rich ink, the conductive layer is formed, the interface state density is remarkably reduced, and the open-circuit voltage of the battery is improved; the ink-jet printing is adopted to replace expensive LPCVD and photoetching mask processes, so that the preparation cost of the TBC battery is remarkably reduced; the laser only heats the back ink area, the silicon substrate is kept at low temperature, and warping of the silicon wafer and attenuation of minority carrier lifetime are avoided.

A method for preparing an aluminum-based composite material in which silicon carbide nanocrystals and micron-sized particles are layered is disclosed. This invention addresses the problems of uncontrollable reinforcement distribution, difficulty in oriented whisker alignment, and difficulty in achieving dense impregnation of preforms under high ceramic content conditions in existing aluminum-based composite materials. The steps of this invention include: Step 1, acid washing of the whiskers and particles; Step 2, preparation of a slurry; Step 3, freeze casting to form a preform; Step 4, vacuum freeze drying; Step 5, sintering of the preform; and Step 6, extrusion impregnation of the aluminum-based composite material. This invention belongs to the field of aluminum-based composite material preparation technology.

The present invention relates to a negative electrode composition that can improve the energy density of a lithium secondary battery, reduce the degree of deterioration during operation of the lithium secondary battery, and further improve the life characteristics by using a negative electrode active material containing silicon oxide containing Si nanocrystals having an average particle size (D50) of 0.1 nm or more and 5 nm or less in combination with a negative electrode conductive material and a negative electrode aqueous binder in an appropriate composition; a negative electrode for a lithium secondary battery containing the negative electrode composition; and a lithium secondary battery containing the same.

The application provides a passivated contact structure based on silicon nanocrystal heterojunction and a preparation method thereof. The passivated contact structure comprises a silicon substrate and an interface oxide layer, a carrier collection layer, a dielectric layer and a heavily doped polysilicon layer which are sequentially arranged on one side of the silicon substrate. The carrier collection layer is composed of at least one silicon nanocrystal thin film. The passivated contact structure has a carrier collection layer which is composed of a silicon nanocrystal thin film with a wide band gap. By using a silicon nanocrystal with a higher band gap, the quasi-Fermi level difference between the silicon nanocrystal layer and the silicon substrate can be widened, so that the qV D of the carrier collection layer and the silicon substrate is improved, and the upper limit of the open circuit voltage is increased.

The invention belongs to the technical field of optical communication, and particularly relates to a high-concentration erbium-doped high-brightness communication band silicon-based light-emitting film and a preparation method thereof. According to the invention, HSQ is taken as a solvent, erbium nitrate pentahydrate is taken as a source of erbium element, and the erbium-doped silicon-based luminescent film with high brightness is obtained through co-doping of ytterbium ions and independent silicon quantum dots, stirring, spin-coating and high-temperature annealing. The HSQ photoresist is used as a precursor material for preparing the silicon nanocrystalline thin film, and after erbium is doped, high-temperature annealing is carried out, so that the formed thin film contains a large amount of silicon nanocrystalline. The silicon nanocrystal serves as a sensitizer in the energy transfer process, absorbs incident photon energy and then transfers and activates erbium ions, and photoluminescence with the emission center wavelength being 1.54 microns is achieved. According to the method, a large number of defects generated by an ion implantation method are avoided, the high vacuum degree does not need to be maintained, the prepared erbium-doped thin film has the advantage that the concentration of silicon nanocrystals serving as an erbium light-emitting sensitizer is high, the preparation steps are simple, and operation is safe.

The application relates to a high-performance composite negative electrode material based on a bulk silicon nanocrystal and a preparation and application thereof, and the preparation method of the negative electrode material comprises the following steps: (1) weighing silicon monoxide powder, a lithium source additive and a heat conduction network material, grinding and mixing to obtain a precursor mixture; (2) placing the precursor mixture on a carrier, carrying out a high-temperature disproportionation reaction, and cooling to room temperature to obtain modified silicon monoxide composite powder, namely a target product. Compared with the prior art, the application can effectively relieve mechanical stress caused by volume expansion of the nanocrystal in a cycle process, avoid particle rupture, and significantly improve the cycle stability of the material and the like.

The invention provides an electron source, a manufacturing method thereof and an electron beam direct writing machine. The manufacturing method comprises the following steps: forming a polycrystalline silicon thin film on a first main surface of a first silicon substrate; a porous silicon structure is formed in the polycrystalline silicon thin film, the porous silicon structure is provided with a first port with pores in the second main surface of the polycrystalline silicon thin film, and a second port with pores is formed in one side, close to the first main surface of the first silicon substrate, of the polycrystalline silicon thin film; a plurality of silicon nanocrystals are formed in the porous silicon structure; bonding the second main surface of the polycrystalline silicon thin film with the first main surface of a second silicon substrate; the first silicon substrate is removed, and the polycrystalline silicon film is thinned, so that the second port of at least part of pores of the porous silicon structure is exposed out of the surface; and forming a first electrode at the second port. According to the invention, the hole type defect between the electron emission region and the substrate is avoided, so that the performance of the electron source is improved.

The invention relates to the technical field of 3D printing materials, in particular to a plant fiber modified 3D printing material and a preparation method thereof. The composite material is prepared from the following raw materials in parts by weight: polylactic acid, plant fiber powder, poly (butylene succinate), porous spherical calcium carbonate, an ethylene-acrylic acid copolymer, sodium alginate, cellulose acetate, plant-type nanocrystals, a cross-linking agent and a lubricating agent, and the plant-type nanocrystals are composed of cellulose nanocrystals, silicon nanocrystals and hydroxyapatite nanocrystals. By adopting the formula, the material can flow more smoothly in the nozzle, so that the problems of extremely easy blockage, empty beating or winding and the like when a melting or photocuring nozzle is used for printing small wire diameters are effectively avoided, the batch rejection rate is reduced, and the production efficiency is improved. Meanwhile, in the post-stretching refining process, even if stretching parameters are adjusted within a large range, the conditions that the suture is prone to being broken due to over-stretching and insufficient in under-stretching strength are not prone to occurring, and therefore the quality and performance of the 3D printing surgical suture are guaranteed.

The invention belongs to the technical field of ceramic fibers, and discloses a silicon carbide-carbide complex-phase micro-nano fiber as well as a preparation method and ultrahigh-temperature application thereof. The preparation method comprises the following steps: spinning polycarbosilane and a metal organic salt solution to obtain fibril, carrying out electron beam irradiation crosslinking curing in an inert atmosphere, cooling to obtain irradiation-infusible fiber, placing the irradiation-infusible fiber in the inert atmosphere, heating to 1300-1800 DEG C under the assistance of tension, and carrying out heat preservation sintering for 1-3 hours to obtain the composite material. According to the obtained silicon carbide-carbide micro-nano fiber, beta-silicon carbide is used as a matrix, and uniformly distributed carbide nanocrystals are embedded in situ among crystal grains of beta-silicon carbide nanocrystals. The silicon carbide-carbide complex phase micro-nano fiber is smooth in surface, compact in structure and good in high temperature resistance and oxidation resistance, has flexibility, ablation resistance and heat insulation performance, and can be applied to the fields of aerospace vehicle large-area heat protection materials, heat sealing materials, heat insulation materials and the like.