2475 results about "Carbon quantum dots" patented technology

A hydrogel composition for photocatalytic hydrogen production and storage. The composition containing a graphene, a TiO₂ nanotube array, and a carbon quantum dot defines a three-dimensional porous and continuous cross-linked structure. Also disclosed is a method of producing this composition.

The present invention provides a process for preparing carbon quantum dots having uniform size by using emulsion, and a process for doping the inside of the carbon structure with other element or replacing the surface with a surface stabilizer having a specific chemical functional group different from existing stabilizers in order to control the properties of the carbon quantum dots. The process for preparing the carbon quantum dots according to the present invention makes a mass production possible and the process thereof is simple. Furthermore, the process is easy to control the size of the quantum dots and the reaction yield rate of the method is excellent. In addition, according to the present invention, it is possible to synthesize carbon quantum dots having uniform size and superior quantum yield rate and it makes it possible to embody the color as equivalent to existing molecular chromophores or heavy metal quantum dots by changing the structure of the chromophore.

The present invention discloses a method for preparing heteroatom doped carbon quantum dot, and application thereof in fields of biomedicine, catalysts, photoelectric devices, etc. The various kinds of heteroatom doped carbon quantum dots are obtained by using a conjugated polymer as a precursor and through a process of high temperature carbonization. These carbon quantum dots contain one or more heteroatoms selected from the group consisting of N, S, Si, Se, P, As, Ge, Gd, B, Sb and Te, the absorption spectrum of which ranges from 300 to 850 nm, and the fluorescence emission wavelength of which is within a range of 350 to 1000 nm. The carbon quantum dot has a broad application prospect in serving as a new type photosensitizer, preparing drugs for photodynamic therapy of cancer and sterilization, photocatalytic degradation of organic pollutants, photocatalytic water-splitting for hydrogen generation, organic polymer solar cell and quantum dot-sensitized solar cell.

The present invention relates to a preparation method of carbon quantum dots with adjustable fluorescence colors, and belongs to the technical field of nanometer materials. According to method, citric acid or a citrate is adopted as a carbon source, a nitrogen-containing compound is adopted as a nitridation agent, hydrogen peroxide is adopted as an oxidant, a hydrothermal synthesis method is adopted to obtain an aqueous solution of carbon quantum dots emitting blue or green fluorescence under ultraviolet light excitation, reaction conditions are easily controlled, and the method is suitable for scale production. The prepared carbon quantum dots have advantages of adjustable fluorescence color, high yield, high quantum efficiency, good result reproducibility and the like, wherein the product can be directly used for tumor cell labeling and live cell imaging labeling. According to the present invention, only the one reactant is required, the raw materials are easily-available and non-toxic, the production process does not require special protection, the reaction condition is easily controlled, and the obtained carbon quantum dots have advantages of high yield, high quantum efficiency, good result reproducibility and the like; and the method has characteristics of high yield, simple preparation process, low cost, easy scale production and the like.

A method for preparing carbon nitride quantum dots comprises the following steps of (1) material preparation, (2) drying and tabletting, (3) heating, (4) separation and (5) drying. Sodium chloride crystals are used as a template, the preparing process is simple and low in cost, and the sodium chloride crystals can be easily removed through water dissolution; melamine is used as the raw material, and annular carbon nitride basic structural units exist in melamine molecules, so that the yield of preparing the quantum dots is high, and product size uniformity is good; the prepared quantum dots are high in specific area, good in water solubility and good in dispersity, have strong fluorescent radiation visible under naked eyes, and have wide application prospects in the fields of fluorescence detection, light emitting devices, biomarker and the like.

The invention relates to nano optical functional materials, especially relates to an organic functional luminescent carbon quantum dots with high luminescent efficiency, a preparation method therefor and applications thereof. The preparation method employs a single-step pyrolysis synthesis method: organic compounds with a low decomposition temperature (150-300 DEG C) is heated at a temperature of 150-350 DEG C (the organic compounds are generally heated for 1-360min and heating methods comprise organic pyrolysis, hydrothermal method and the like) and subjected to a pyrolytic reaction; organic functional luminescent carbon quantum dots are obtained after post-treatment and purification. Surfaces of carbon quantum dots are modified with organosilane or organic high-molecular compounds with acylamino to form the organic functional luminescent carbon quantum dots. The organic functional luminescent carbon quantum dots can be used as luminescent functional materials, optical functional nano hybrid composite materials or used as biological living cell imaging materials.

The invention relates to a carbon quantum dot, precious metal and zinc indium sulfide composite photocatalyst and a preparation method thereof. The composite photocatalyst contains a hexagonal-phase zinc indium sulfide (ZnIn2S4) matrix, and reduced carbon quantum dots and precious metal particles which are carried on the surface of the ZnIn2S4 matrix, wherein the ZnIn2S4 matrix is of a peony-flower-shaped structure, the particle size of the matrix is 0.1-10 micrometers and the BET specific surface area of the matrix is 10-200 m<2>/g; the particle size of the carbon quantum dots and the precious metal particles is 1-10 nm; precious metal refers to one or a mixture of some of gold, platinum, silver or palladium. The composite photocatalyst has high catalytic activity (with a hydrogen production rate up to 1mmol.h<-1>g<-1>) under irradiation of visible light (more than or equal to 400nm), and has long service life (over 50 hours).

The invention provides a method for extracting carbon quantum dots from activated carbon, which comprises the following steps of: adding dry activated carbon powder to salpeter solution and stirring for backflow; performing reduced pressure distillation for evaporating suspension obtained by backflow to dryness; dispersing obtained black solids in water, and neutralizing obtained solution with sodium hydroxide; and finally, centrifugating neutralized black suspension for removing precipitation, separating supernatant fluid by using an ultrafiltration centrifugal tube or an ultrafiltration membrane, collecting filtrate, and drying the filtrate to obtain carbon quantum dots. The method uses cheap and available activated carbon as carbon sources, and can obtain a large number of carbon quantum dots by simple chemical oxidation process and simple subsequent processes of evaporation, saturation, centrifugation and ultrafiltration. The carbon quantum dots are graphite structure nanocrystals with the grain diameter of 3 to 5 nm, the surfaces of which have a large amount of hydroxide radicals. The carbon quantum dots have good fluorescence and electrochemiluminescence.

The invention presents a method for synthesis of a carbon quantum dot modified TiO2 composite nano-photocatalyst. The method includes: using vitamin C as a carbon source, in a mixed solution of ethanol absolute and deionized water, preparing a carbon quantum dot with an up-conversion characteristic by a hydrothermal process, then preparing spherical TiO2 powder by a sol-gel process, mixing the spherical TiO2 powder with a carbon quantum dot solution, and performing drying, thus obtaining the composite nano-photocatalyst. The method provided in the invention makes use of the up-conversion characteristic of the carbon quantum dot to modify TiO2 so as to prepare the composite nano-photocatalyst, has the advantages of simple operation, and low cost, etc., and has very high practical value and application prospects.

The invention discloses a method for preparing a photoluminescence carbon quantum dot. The method includes the following steps of drying and dehydrating a solid residue obtained after squeezing soybeans into soya-bean milk, placing the dried and dehydrated solid residue in an electrothermal blowing dry box to heat and carbonize to obtain a crude product of the carbon quantum dot, grinding the crude product of the carbon quantum dot, sieving, dispersing the sieved crude product of the carbon quantum dot in deionized water, uniformly stirring, still standing, centrifuging, evaporating an obtained aqueous solution containing the carbon quantum dot, and freeze drying to form a powdered shape to finally obtain the photoluminescence carbon quantum dot. According to the method for preparing the photoluminescence carbon quantum dot, a household bean juice maker is used for obtaining soybean dregs which serve as raw materials, the source of the raw materials is wide, the photoluminescence carbon quantum dot is prepared through low temperature heating and carbonization, the operation is simple, the cost is low, the yield is high, the preparation process equipment is simple and easy, the operation can be completed within an extremely short time, and the method is easy to popularize.

The invention provides carbon quantum dots with room-temperature phosphorescence and delayed fluorescence properties. The carbon quantum dots can generate fluorescence under the excitation of ultraviolet light with the wavelength of 315-475nm, wherein the fluorescence intensity reaches the maximum when the excitation wavelength is 375nm. The particle size distribution range of the carbon quantum dots is 2-6nm. The brand-new carbon quantum dots with room-temperature phosphorescence and delayed fluorescence properties are synthesized from isocyanate under the action of microwaves. The carbon quantum dots have high yield, are oil-soluble, and can be compounded into a polymer material in situ without aggregation. The structure of the carbon quantum dots contains certain amounts of O, N and other heteroatoms with lone electron pairs, thereby increasing the transition probability from singlet state to triplet state under excitation. Meanwhile, the matrix performs the functions of reducing the nonradiative transition and quenching the triplet-state oxygen, so that the prepared carbon quantum dots have the visible stable room-temperature phosphorescence and delayed fluorescence properties in the matrix.

The invention relates to a preparation method of fluorescence carbon quantum dots. The preparation method comprises the following steps: a first step, collecting plant leaves, washing the leaves and drying the leaves in the air; a second step, burning the clean leaves to obtain a black solid; a third step, grinding the black solid into a powder, and dispersing the powder in a solvent to obtain a well dispersed suspension through magnetic stirring and ultrasonic treatment; a fourth step, centrifuging the suspension or carrying on a separating process using a filter membrane, removing precipitation to obtain a clear solution; and a fifth step, removing the solvent in the clear solution, then obtaining the solid of the fluorescence carbon quantum dots. According to the invention, a variety of the plant leaves can be employed as raw materials, sources of the raw materials are wide and preparation processes of the method are simple and easy.

The invention discloses a microwave-assisted method for preparing carbon quantum dots rich in amino groups on the surfaces thereof and application of the amino carbon quantum dots. The method comprises the following steps: using aqueous solution of glucosamine phosphate as a raw material, heating the raw material with a microwave oven as a reaction platform to obtain carbon quantum dots with fluorescent properties, and removing residues and moisture by dialysis and rotary evaporation to obtain carbon quantum dot powder. The method provided by the invention for preparing amino carbon quantum dots is simple in operation and easy in generalization, has low cost, high yield, simple preparation process and equipment, and can complete the operation in a very short time. The obtained carbon quantum dots are rich in amino groups on the surfaces thereof and soluble in water, the fluorescence quantum yield is greatly increased, and the carbon quantum dots are successfully used for labeling living cells, therefore the method has broad application prospects.

The invention discloses a mesoporous silica/carbon dot nanometer composite and a preparation method thereof. The preparation method of the mesoporous silica/carbon dot nanometer composite includes steps of synthesizing hexagonal ordered mesoporous silica SBA-15 (nearly 8 nm in bore diameter) by triblock copolymer P123; steeping the mesoporous SBA-15 silica in a certain concentration of citric acid solution for adsorption, and filling citric acid molecules into holes of mesoporous SBA-15; roasting the SBA-15 filled with citric acid in a chamber resistance furnace to obtain mesoporous silica/carbon dot nanometer composite. The carbon dots are uniformly loaded in the holes of the mesoporous SBA-15, and the multifunctional nanometer composite with ordered mesoporous structure and fluorescent function is prepared. The mesoporous silica/carbon dot nanometer composite has the advantages of simplicity in preparation technique, moderate reaction conditions and environment friendliness.

The invention discloses a nitrogen-doped fluorescent carbon quantum dot and a preparation method and application thereof, and belongs to the technical field of material science. Fish wastes (such as fish scales, bones and skins) are cleaned, then hydrothermal reaction is directly performed to obtain nitrogen-doped fluorescent carbon quantum dot aqueous dispersion, and finally filtration, dialysis and freeze-drying are performed to obtain nitrogen-doped fluorescent carbon quantum dot solid. The size of the nitrogen-doped fluorescent carbon quantum dot prepared by using the preparation method disclosed by the invention is smaller than or equal to 10nm, the nitrogen content is smaller than or equal to 20 percent, the surface of the quantum dot has nitrogen-containing and oxygen-containing functional groups, and the quantum efficiency is 17-30 percent. The nitrogen-doped fluorescent carbon quantum dot and the preparation method and application thereof have the advantages that the preparation method is environmental-friendly, the operation is simple, the requirements on equipment are low, the preparation method is suitable for large-scale production, and the prepared nitrogen-doped fluorescent carbon quantum dot has excellent fluorescent performance and can be widely applied to fields such as photoelectric materials, biological imaging and fluorescent probes.

The invention discloses a new method for preparing water-soluble carbon quantum dots by taking graphite impurities as a raw material, and the graphite impurities are generated when a single-walled carbon nanotube is prepared by an arc process. The method comprises the steps of: adding the graphite impurities into a water solution containing a surface active agent, dispersing and centrifuging to obtain graphite particles with narrower size distribution; then, carrying out reaction between the graphite particles and a strong oxidant; adjusting the sizes of the carbon quantum dots by changing the reaction time and temperature; and finally, obtaining the water-soluble carbon quantum dots by alkali neutralization and dialysis bag separation. Compared with the prior art, the method for obtaining the carbon quantum dots by treating the graphite particles by the strong oxidant is simple in technology, and the quantum dots with different particle sizes can be obtained by controlling the size of the raw material, the experimental temperature and the reaction time; and the method is low in cost, thus being suitable for commercial production.

The invention relates to a method for preparing biomass based carbon quantum dots. The method comprises the following steps: carbonizing or activating a biomass material so as to obtain a carbonized product of which the carbon content is greater than or equal to 80%, performing nano quantization on the carbonized product by using a thick acid mixing liquid so as to obtain water-soluble fluorescent carbon quantum dots, changing the reaction temperature so as to adjust the fluorescent color of the carbon quantum dots, and performing retaining separation by using a dialysis bag, thereby obtaining carbon quantum dots in a rectangular diamond cluster about 5nm. Compared with the prior art, the method is wide in raw material source based on natural biomass sources and green and environment-friendly. The chemical oxidation preparation process is simple, and preparation of small-size carbon quantum dots can be easily achieved. The carbon quantum dots are stable in fluorescent effect and good in water solubility, and can be used in fields such as biological imaging.

The invention discloses application of a multifunctional carbon quantum dot taken as a fluorescent whitening agent in the fields of spinning printing and dyeing, washing agents, papermaking, plastics, leathers or coatings and the like. The carbon quantum dot disclosed by the invention has the advantages of wide application field, good whitening effect and good light resistance, is innoxious and environmentally friendly, can be applied to the fields of spinning printing and dyeing, washing agents, papermaking, plastics, leathers or coatings and the like, and can generate unforeseeable technical effect because the carbon quantum dot can generate active oxygen free radicals under the condition of illumination, wherein the unforeseeable technical effect is as follows: the bacteria attached to the surfaces of spinning printing and dyeing materials, the washing agents, paper sheets, the plastics, the leathers or the coatings and the like can be effectively killed after the spinning printing and dyeing materials, the washing agents, paper sheets, the plastics, the leathers or the coatings and the like which are doped with the carbon quantum dot absorb ultraviolet light.

The invention discloses a use of a heteroatoms doped aqueous carbon quantum dot as a novel efficient photocatalyst. The various-heteroatoms doped aqueous carbon quantum dot contains one or more of heteroatoms comprising N, S, Si, Se, P, As, Ge, Gd, B, Sb, Te and the like, and the absorption spectrum wavelength of the heteroatoms doped aqueous carbon quantum dot is in a range of 300-850nm. Researches find that the heteroatoms doped aqueous carbon quantum dot can realize the efficient catalytic degradation of organic pollutants in the environment under the irradiation of sunlight, can also realize the efficient photolysis of water to prepare hydrogen, and has huge application prospects in the environment and energy fields.

The invention discloses a carbon quantum dot-poly N-isopropylacrylamide composite material and a preparation method thereof. An N-isopropylacrylamide polymer is grafted to the surface of carbon quantum dots obtained by microwave treatment by adopting an atom transfer radical polymerization (ATPR) method. The preparation method is simple, convenient and mild in conditions. Modified carbon nano particles have fluorescence property and temperature sensitivity.

The invention relates to a preparation method of doped carbon nitride fluorescent quantum dots.According to the preparation method, melamine and compounds corresponding to doped atoms serve as raw materials, while melamine molecules are roasted to form a carbon nitride structure, the doped atoms enter the carbon nitride structure through a chemical reaction, a doped carbon nitride block material is formed, and the block material is subjected to ultrasound crushing in an alcohol solvent to prepare the doped carbon nitride fluorescent quantum dots which are uniform in quantum size and grain size.The dried quantum dots are good in water solubility and dispersibility and have high fluorescent quantum dot yield.The method can be used for preparing the doped carbon nitride quantum dots in batches, the synthesis method is simple, and repeatability is good.The synthesized quantum dots have wide application prospects in the fields of fluorescence detection, light-emitting devices, biological marking and the like.