34results about How to "Stoichiometric ratio" patented technology

The invention discloses an alloy quantum dot core with uniform internal and external components and a preparation method thereof, wherein the method comprises the steps: stirring and mixing evenly at least two pre-prepared cationic precursor solutions, heating to a predetermined temperature, injecting at least one prepared anionic precursor solution, carrying out a nucleation reaction, continuing to inject the cationic precursor solutions or the anionic precursor solution or simultaneously inject the cationic precursor solutions and the anionic precursor solution at a gradually changed speed in the nucleation reaction process, making the reaction rate of all the components in the nucleation reaction process remained relatively stable and making the nucleation stoichiometric ratio relatively consistent, and thus obtaining the alloy quantum dot core with uniform internal and external components. By the method, the problems that an alloy quantum dot core has non-uniform internal and external components, low luminous efficiency and unstable wavelength and fluorescence intensity can be effectively solved, and the method provided by the invention has the advantages of simple operation, easy control, high repeatability and the like.

The invention discloses an ultrafine titanate nano powder and a preparation method. The method comprises the following steps: 1) taking an alcohol compound as a solvent, under the existence condition of a surfactant, reacting tetrabutyl titanate and barium hydroxide octahydrate or/and strontium oxide octahydrate to obatain a titanate nanoparticles sol; 2) adding water in the titanate nanoparticles sol, centrifuging to obtain the titanate deposition, and drying the deposition to obtain the titanate nano powder. The method has the advantages of high efficiency and energy saving, simple process and safety, can realize large batch production method of the titanate nano powder; and the method has universality to preparing nano powder with various perovskite type structure. The prepared powder has small granularity, good dispersibility, large specific surface area, high dimension uniformity, high chemical activity and wide application of electronic ceramic and chemical catalysis.

The invention relates to a method for preparing high-quality copper indium sulfide by employing a single-source molecular precursor. The method comprises the following steps: mixing copper chloride and indium chloride powder to prepare a solution, and preparing sodium diethyl dithiocarbamate powder into a solution; adding the former solution to the latter solution slowly in the way of stirring, filtering and drying precipitate, putting the obtained product into an autoclave and adding ethanol used as a solvent; sealing the autoclave and then placing the autoclave in an electric dry oven, heating and cooling naturally, washing with deionized water and absolute ethyl alcohol, and finally drying to obtain black copper indium sulfide powder. The invention solves the defaults of a gas phase method and a liquid phase method of expensive equipment, complex process operation, low yield, and the uniformity of the inner and outer composition of the product and the generation of a core-shell structure which are caused by the relatively larger solubility difference of the multi-source precursor in solvent. The invention has the advantages of cheap and easily obtained raw materials, no toxic H2S gas or vacuum environment, and simple process, and can obtain pure tetragonal phase copper indium sulfide with sea urchin-like morphology and high degree of crystallinity.

The invention discloses a synthesis method for a selenium germanium gallium barium polycrystal and a growth method for a selenium germanium gallium barium monocrystal. The growth of the polycrystal comprises the following steps: putting elemental Ga, elemental Ba and elemental Ge into a PBN boat; then placing the PBN boat at one end of a quartz tube and placing elemental Se at the other end of thequartz tube; conducting vacuumizing, and then carrying out heat sealing; and then putting the quartz tube into a horizontal double-temperature-region resistor furnace for synthesizing, so as to obtain a high-purity single-phase selenium germanium gallium barium polycrystal raw material, wherein the yield of the raw material is greater than 99%. The growth of the selenium germanium gallium bariummonocrystal comprises the following steps: adding the selenium germanium gallium barium polycrystal into a crystal growth crucible and vertically placing the crystal growth crucible into a quartz tube; conducting vacuumizing, and then carrying out heat sealing; and then putting the quartz tube into a vertical double-temperature-region resistor furnace, so as to obtain the selenium germanium gallium barium monocrystal after the growth of the monocrystal is finished. The selenium germanium gallium barium monocrystal obtained by the method disclosed by the invention has the advantages of few defects, high infrared band transmission rate and the like and can be used as a far infrared laser frequency conversion material.

The invention relates to a preparation method of LiXSe2 polycrystalline compound and mono-crystal. The preparation method comprises the following steps: filling Li, In, Ga and Sa monomers into an inner-layer crucible and a quartz crucible and packaging in vacuum; filling the crucibles into a swinging furnace and carrying out heat preservation and swinging at the temperature above the smelting point of the LiXSe2 compound; then cooling to room temperature. The obtained LiXSe2 (X is equal to In/Ga/InyGa1-y) compound meets a stoichiometric ratio. By controlling the temperature, the Li, In, Ga andSa monomers are subjected to compound reaction at temprature close to smelting points of the Li and the Se under relatively low steam pressure of the Li and the Se, so as to obtain Li2Se, InxSey andGaxSey compounds and the like and fix the chemical activity of the Li and the Se and reduce the loss of Li and Se components; the deviation of the stoichiometric ratio of chemical components of the LiXSe2 mono-crystal (X is equal to In/Ga/InyGa1-y) obtained by the growth of the polycrystalline raw material LiXSe2 (X is equal to In/Ga/InyGa1-y) obtained by the invention can be controlled within 5 percent.

The invention discloses a preparation method of ZnSe nanocrystal. The preparation method of the ZnSe nanocrystal comprises the following steps: S1, preparing selenium precursor solution, namely preparing a reaction solution by utilizing oleylamine, a selenium simple substance and a reducing agent, heating and reacting, and thus the selenium precursor solution is obtained, wherein concentration of the selenium precursor solution in the reaction solution is 0.25-1.5mol/L, the mole ratio of the reducing agent to the selenium simple substance is more than 1:1, and the reducing agent is dimethylamine borane or sodium borohydride; S2, preparing a zinc precursor solution, namely dispersing a zinc source in a reaction solvent to obtain the zinc precursor solution, wherein mole ratio of the zinc source to the selenium simple substance is 1:(1-1.5), and the reaction solvent is oleylamine or a mixed solvent of octadecene and stearic acid; and S3, preparing ZnSe nanocrystal, namely heating the zinc precursor solution obtained in the step S2 to 150-350 DEG C in an anhydrous oxygen-free system, then injecting the selenium precursor solution obtained in the step S1 into the zinc precursor solution, and reacting for at least 10 minutes, and thus the ZnSe nanocrystal is obtained. By adopting the preparation method of the ZnSe nanocrystal, high-quality ZnSe nanocrystal can be prepared.

The invention discloses a preparation method of a hollow PtPd nanometer material, comprising the following steps: (1) uniformly dispersing cuprous oxide to low mass molecule alcohol, adding a low mass molecule alcohol solution containing PtCl6(2-) and PdCl4(2-) while stirring, and carrying out ultrasonic stirring and mixing; (2) dripping a mixed solution obtained in step (1) to water, and carrying out stirring reaction for 30-60min at the temperature of 20-25 DEG C; (3) transferring a reaction system in the step (2) to a heating device and heating to 60-65 DEG C at the heating rate of 1-3 DEG C/min, and continuing to react for 90-120min at current temperature; and (4) removing a cuprous oxide core after reaction is completed so as to obtain the hollow PtPd nanometer material. The hollow PtPd nanometer material prepared by adopting the method can meet the stoichiometric ratio of reactants, and can uniformly and precisely copy the morphology of a cuprous oxide template.

The invention discloses a zinc gallate nano material as well as a preparation method and application thereof. The zinc gallate nano material has a nanowire structure which is cross-linked at the bottom and is vertically arranged in order. The zinc gallate nano material has a good application prospect as a semiconductor material and/or a luminescent material, and can be widely applied to the fields of ultraviolet detectors, fluorescent luminescent powder, gas sensors and the like.

The invention belongs to a method for preparing a CIGS thin-film solar cell absorption layer employing a co-sputtering method. The method comprises the steps as follows: (1) a substrate is provided, radio-frequency sputtering is carried out by a copper indium gallium selenide target, meanwhile, DC sputtering is carried out by an indium target and a copper indium gallium selenide preformed layer is prepared in a co-sputtering manner; and (2) the copper indium gallium selenide preformed layer is put into a quick annealing furnace, is selenized under nitrogen protection for twice and is naturally cooled to a room temperature to obtain the CIGS thin-film solar cell absorption layer. By a technological approach of carrying out sputtering by a standard CIGS quaternary target, large-scale industrial production is facilitated; the loss of an indium element caused by the standard CIGS quaternary target in the sputtering process can be effectively avoided through the method; and a CIGS absorption layer material in accordance with the stoichiometric ratio can be obtained. Annealing treatment is carried out on the prepared CIGS absorption layer through a two-step heating method; the selenylation completeness and crystallinity can be further strengthened; and the high-quality CIGS with a uniform surface and a consistent thickness can be obtained.

The invention relates to a method for preparing a large-area beta-phase In2Se3 single crystal film. The method comprises the following steps that: 1) chemical cleaning and chemical corrosion treatmentare carried out on a silicon substrate with crystal orientation of (111), so that a hydrogen-passivated silicon substrate with a clean surface can be obtained; 2) the prepared silicon substrate is transferred into a molecular beam epitaxy system, heating is performed to 180 DEG C, and degassing is performed until the vacuum degree of the system is superior to 8*10 <-10 > mbar; (3) the substrate naturally cools to a growth temperature range after the substrate is degassed, and meanwhile, an In beam source and a Se beam source are opened to grow and synthesize an In2Se3 polycrystalline film; (4) the temperature of the substrate is immediately raised to 300-350 DEG C after the growth of the polycrystalline film is finished, and subsequent annealing is carried out for 5 minutes; and 5) heating is immediately stopped after annealing is finished, and the substrate naturally cools to room temperature, so that a high-quality beta-phase In2Se3 single crystal film can be obtained. According tothe method for growing the beta-phase In2Se3 thin film, the molecular beam epitaxy technology is combined with the subsequent in-situ annealing process, and the large-area high-quality beta-phase In2Se3 single crystal thin film can be prepared on the hydrogen-passivated silicon substrate at a low temperature.

The invention discloses a method for preparing a hollow PtPdnano material with cuprous oxide as a template. The method comprises the following steps that (1) the cuprous oxide is uniformly dispersed into water, an aqueous solution containing PtCl<6><2-> and PdCl<4><2-> is added under the stirring condition at the temperature of 20-25 DEG C, and a stirring reaction is conducted for 30-60 minutes at the temperature; (2) the reaction system in the step (1) is moved into a heating device and heated to the temperature of 60-65 DEG C at the heating speed of 1-3 DEG C/min, and the reaction continues to be conducted for 90-120 minutes at the temperature; and (3) after the reaction is finished, cuprous oxide cores are removed, and the hollow PtPd nano material is obtained. According to the hollow PtPd nano material obtained through the method, the shape of the cuprous oxide template is accurately duplicated, the atomic ratio Pt/Pd of the nano PtPd nano material is made to be close to the atomic ratio Pt/Pd of the reaction solution, the requirement for the stoichiometric ratio of reactants is met, and accurate component controlling is achieved.