1441 results about "Carbon dot" patented technology

The invention belongs to the technical field of preparation of a carbon nano material, and particularly relates to a method for preparing a carbon dot having a high fluorescent quantum yield from citric acid and different nitrogen-containing molecules. The method comprises the following steps: weighing 1-10 mmol of solid citric acid, and dissolving in 10 ml of deionized water; weighing 1-10 mmol of ethylenediamine, ethylamine, propylamine, butanediamine, n-hexylamine, p-phenylene diamine or urea, adding into the citric acid solution, and uniformly stirring; transferring the solution into a hydrothermal or high-pressure microwave reaction kettle, reacting under hydrothermal or microwave conditions, and naturally cooling the reaction kettle to room temperature, thus obtaining a yellow or brown carbon dot water solution; and finally, purifying the carbon dot water solution, evaporating, and drying to obtain pure carbon dot solid powder. The carbon dot solution can send out bright blue fluorescence under the irradiation of a handheld ultraviolet lamp. The invention has wide application prospects in the fields of biological imaging, fluorescent printing and the like.

The present invention relates to the water soluble self fluorescent quantum carbon dots (C-dots). These C-dots are isolated from carbon soot in one embodiment a wax soot solvent washed and isolated from other larger material by filtration such as by membrane filtration. The C-dots can be varied in their color by change of their size and by the amount of oxidative groups' position on each C-dot.

The invention relates to a method for preparing water-soluble fluorescent carbon dots. The method comprises the following steps: by adopting a citric acid as a carbon source, urea as a passivator and a dopant and deionized water as solvents aiming at the conditions that the fluorescent carbon dots are high in accuracy and difficult to synthesize, preparing a carbon dot water solution by adopting a hydrothermal synthesis method; and preparing the carbon dots by the following processes of preparing the solution, air-tight reaction, filtering, dialyzing, freezing and drying, and grinding. The technology is advanced in process, rapid and efficient, accurate and specific in data, and good in product shape; the product is green powder particles; and the diameters of the particles are smaller than or equal to 5.5nm; the product is high in purity which can be up to 99%, and good in water-solubility which can be up to 99.5%. The method is an ideal method for preparing the fluorescent carbon dots. The product can be applied to the fields such as ion detection, bioimaging, photoelectric devices and composite materials.

A mechanically stable and oriented scanning probe tip comprising a carbon nanotube having a base with gradually decreasing diameter, with a sharp tip at the probe tip. Such a tip or an array of tips is produced by depositing a catalyst metal film on a substrate (10 & 12 in FIG. 1(a)), depositing a carbon dot (14 in FIG. 1(b)) on the catalyst metal film, etching away the catalyst metal film (FIG. 1(c)) not masked by the carbon dot, removing the carbon dot from the catalyst metal film to expose the catalyst metal film (FIG. 1(d)), and growing a carbon nanotube probe tip on the catalyst film (16 in FIG. 1(e)). The carbon probe tips can be straight, angled, or sharply bent and have various technical applications.

The invention relates to a dual emission rate type fluorescent probe for visually detecting carbon dots-Au nanoclusters of mercury ions and a preparation method. Dual-emission composite silicon dioxide nanoparticles are composite silicon dioxide nanoparticles formed by utilizing carbon dot covered silicon dioxide particles as cores and covalently coupling the surfaces of the carbon dot covered silicon dioxide particles with the Au nanoclusters after surface amination. The carbon dots located in the silicon dioxide nanoparticle cores are taken as reference fluorescence signals, the Au nanoclusters on the outer layers are taken as response fluorescence signals, and the signals are used for Hg<2+> selective recognition. The Au nanoclusters as the response fluorescence signals are connected to the surface of a silicon layer through covalent bond connection, and one stable nano-fluorescent probe is formed. When the dual-fluorescence composite nanoparticles are taken as the rate type fluorescent probes, the intensity of the carbon dot fluorescence signals in the cores basically keep unchanged, and the Au nanoclusters on the outer layers can be bonded with Hg<2+> selectively so as to result in fluorescence quenching of the Au nanoclusters on the outer layers.

The invention relates to carbon dots with high fluorescent quantum yield, and an application thereof in fluorescent color development, and belongs to the application field of fluorescent carbon nanomaterials. Specifically, the invention relates to the carbon dots with the high fluorescent quantum yield which are synthesized by using citric acid and ethene diamine as raw materials as a fluorescent ink for writing or fluorescent printing, and further broadens the application thereof in fluorescent electrospining, fluorescent micro arrays and fluorescent composites. The carbon dots with the high fluorescent quantum yield are obtained by blending 1-100 mmol of citric acid and 1-100 mmol of ethene diamine in 5-100 mL of deionized water and transferring the mixture into a reaction kettle; carrying out a hydrothermal reaction for 2-10 hours at a temperature of 100-500 DEG C; cooling the reaction kettle to a room temperature after the reaction is finished to obtain a water solution of the carbon dots with the high fluorescent quantum yield; pouring the water solution of the carbon dots in a dialysis bag with a molecular weight of 3,500; dialyzing for 48-60 h; spin drying a dialysis outer solution and vacuum drying.

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 present invention relates to a transition metal-doped carbon fluorescent quantum dot preparation method, which comprises: dissolving a metal chelating agent and a transition metal salt in an organic solvent, carrying out a solvothermal reaction, and carrying out concentration purification after the reaction to prepare the transition metal-doped carbon fluorescent quantum dots having good water solubility. According to the present invention, the operation of the method is simple, the metal ion doping on the carbon fluorescent quantum dots can be achieved without harsh reaction conditions or large instruments, such that the characteristic that the long wavelength fluorescence emission is not easily achieved by the general carbon dots can be achieved; the obtained carbon fluorescent quantum dots have characteristics of good water solubility, wide fluorescence emission range, and maximum emission wavelength change along with concretion change; and with the characteristics of the preparation method, the prepared transition metal-doped carbon fluorescent quantum dots provide great application values in the fields of biological labeling sensing and medical imaging, photoelectricity, light-emitting device preparation, and the like.

The invention relates to a method for preparing luminescent carbon dots from carbohydrate. The carbohydrate based carbon dots prepared by the invention can be used for biological imaging and analysis to determine the content of metal ions. The method for preparing luminescent carbon dots from carbohydrate provided by the invention is as below: mixing carbohydrates with a modifier with amino at different molar ratios; reacting for a certain time by a hydrothermal method; filtering; regulating the pH to a neutral state, conducting dialysis and purification to remove excessive salt, so as to obtain the carbohydrate based luminescent carbon dots. The method for preparing the luminescent carbon dots provided by the invention uses carbohydrates as raw materials, which are easily available and have low cost; the obtained carbon dots have high quantum yield; and the equipment for the preparation process is simple,the method can be completed in general chemistry laboratory, and is easy for popularization.

The invention discloses a method for preparing carbon dots with a hydrothermal process on the basis of plant leaves. The plant leaves are transferred into a reaction kettle, ultrapure water is added, and the mixture is uniformly mixed and subjected to hydrothermal treatment at the temperature of 130 DEG C-250 DEG C for 2-15 hours; the mixture is cooled and filtered to obtain a brown yellow liquid, the brown yellow liquid is subjected to dialysis for 15-48 hours by a dialysis bag with interception of 3,500, and dialysate is collected; or high-speed centrifugation is performed, and fluorescent carbon dots are obtained. The method is simple and safe to operate, environment-friendly raw materials are used, chemical reagents and surface passivation are not required for assisting synthesis, and the method can be applied to the fields of fluorescence labeling, analysis, sensing, catalyzing and the like.

The invention provides a preparation method and a product of full-color carbon dots for multi-color fluorescent printing. Citric acid is used as a single carbon resource, a nitrogen-containing compound is added, and a solvothermal reaction is carried out for 6-8 hours for obtaining a full-color carbon dot mixture. The fine separation of blue, green, yellow and orange fluorescence carbon dots can be realized through the regulation and control of the volume ratio of methanol to dichloromethane by using a column chromatography method. The obtained carbon dots have excellent water solubility, light stability and luminosity, so that the obtained carbon dots can be used to prepare multi-color fluorescent ink, and multi-color printing is realized. The preparation process provided by the inventionis simple, the repeatability is strong, the reaction condition is mild, and the product has excellent stability and practicability.

The invention discloses preparation of an ECL (electro chemical luminescence) DNA (Deoxyribose Nucleic Acid) sensor based on a 3D paper chip, and application of the sensor to simultaneous detection on Hg<2+> and Ag<+>. The preparation method of the sensor (the schematic diagram of which is shown in the figure) comprises the following steps of: designing a micro-fluidic chip pattern on a computer, and preparing a 3D paper chip sensor; preparing nano materials such as a porous gold nanowire, PdAg alloy, a carbon point and P acid according to existing methods, preparing PdAg@CQDs and PdAg@P-acid with signal amplification functions as ECL probes, and respectively compounding the ECL probes with DNA subjected to specific binding with Hg<2+> and Ag<+>; and modifying the porous gold nanowire to the surface of an electrode of the sensor by an electrode surface modifying technology, and absorbing a DNA segment to prepare the DNA sensor. The method for simultaneously detecting Hg<2+> and Ag<+> comprises the following steps of: connecting the modified electrode to an ECL apparatus, and detecting Hg<2+> and Ag<+> in a sample extracting solution. The electrode of the sensor is strong in specificity and high in sensitivity, and is capable of reaching a p mol level. When the paper chip sensor easily processed is used for simultaneously detecting two materials on the same electrode, the detection efficiency is improved, and the cost is lowered.

The invention relates to the field of a carbon nano material, and provides a nitrogen-doped fluorescent carbon-dot and a carbon-dot graphene composite as well as a production method and an application thereof. The nitrogen-doped fluorescent carbon dot is characterized in that the nitrogen element exists in the form of pyridine nitrogen, pyrrole nitrogen and graphitic nitrogen; the nitrogen atom and carbon atom are in a molar ratio of 0.035 to 0.057; the average granularity is 2.5nm to 4.1nm. The invention also provides a preparation method of a fluorescent carbon dot. The preparation method comprises the following steps: (1) carbonizing coal with high content of nitrogen to obtain a carbonized material, wherein the coal with high nitrogen content refers to the coal with the nitrogen content of 1.1 to 3.0 percent; (2) producing an anode through the obtained carbonized material, and electrochemically oxidizing the anode to obtain the fluorescent carbon dot. The invention also provides a carbon-dot-graphene composite material prepared through the nitrogen-doped fluorescent carbon dot. In addition, the invention also provides an application of the fluorescent carbon dot in the fields such as photoelectric devices, biological imaging, oxidation-reduction electric catalyst, detection and sensing and an application of an oxidation-reduction electrochemical catalyst in the field of a fuel battery.

The invention discloses a method for quantitative detection of biological molecules capable of being metabolized to generate H2O2 in serum by means of a ratiometric fluorescent probe. The method includes firstly preparing copper-nitrogen codoped carbon dots Cu-CDs; then reacting corresponding oxidase and the biological molecules capable of being metabolized to generate H2O2 to generate H2O2; catalyzing the H2O2 and a substrate that is o-phenylenediamine with horseradish peroxidase to generate an oxidation product DAP having yellow fluorescence; then adding the Cu-CDs into the DAP; allowing the DAP and the Cu-CDs to form ratiometric fluorescence, with the ratio I<572>/I<460> of fluorescence intensities of the DAP and the Cu-CDs being in a linear relationship with the concentration of a substance to be detected; and performing quantitative assay of the biological molecules in the serum according to the ratio of fluorescence intensities. The method is high in sensitivity and simple and convenient in detection, and has high selectivity and high affinity of immunoreactions.

The invention discloses a preparation method of a double-emission carbon-based nano probe prepared based on an electrostatic interaction induced self-assembling method and application of a product ofthe preparation method to in-vivo and in-vitro temperature detection of organisms, and belongs to the technical field of colorimetric fluorescence detection. The preparation method comprises synthesisof blue fluorescence carbon dots (B-CDs) which have no temperature sensitivity and negative charges on surfaces, preparation of red fluorescence carbon dots (R-CDs) which have temperature sensitivityand positive charges on surfaces and preparation of the double-emission carbon-based nano probe. According to the double-emission carbon-based nano probe obtained by the preparation method, the double-emission carbon-based nano probe has different responsiveness aiming at different temperature and has different compound temperature color changes; the double-fluorescence emission nano probe can beused for colorimetrically detecting in-vivo and in-vitro temperature of the organisms by naked eyes, and has high sensitivity (0.93 percent/DEG C) and operation repeatability, so that the double-fluorescence emission nano probe provides convenience for biological imaging, temperature sensing, environment monitoring, food safety and the like.

The invention discloses a molecular imprinting electroluminescent sensor for detecting veterinary drug residue by taking a battery as power and a method for detecting veterinary drug residue. A preparation method of an electrode (a schematic diagram is shown in the figure) comprises the following steps of: preparing MIP (Molecularly Imprinted Polymer)s sol of the veterinary drug residue; preparing a carbon dot and preparing a graphene nano material according to documents; and modifying graphene, the carbon dot and the MIPs sol onto the surface of the electrode of the sensor. The method for detecting the trace veterinary drug residue comprises the following steps of: connecting the modified electrode to an electrogenerated chemiluminescence instrument, and detecting the veterinary drug residue in a sample extract by taking the battery as the power. The molecular imprinting electroluminescent sensor disclosed by the invention has the advantages that the specificity of the electrode is strong and the sensitivity is high and can be up to a ng grade; only 3-5 minutes are spent on a basic detection process; and the cost is low. The method for detecting the veterinary drug residue by adopting the electrode is quick and easy to operate, the reaction is automatically completed by instruments and results are automatically recorded by the instruments.

The invention discloses a ratio-type fluorescent probe based on a carbon dot and a europium complex, a preparation method of the ratio-type fluorescent probe and an application method of the ratio-type fluorescent probe in a water sample detection technology. A hyperfluorescence rare earth complex and the carbon dot are taken as a double luminous center, a covalent binding manner is adopted for bonding two luminophors together, and ratio-type detection on Cu<2+> ions in a water sample is carried out by virtue of strength ratio of the hyperfluorescence rare earth complex to the carbon dot. The ratio-type fluorescent probe has good selectivity and sensitivity.

The invention discloses a method of detecting adenosine with a fluorescent sensor on the basis of an aptamer. In the method, gold nano particles modified with the aptamer are used as a recognition probe and an energy acceptor, and carbon dots modified with an aptamer complementary chain are used as a fluorescent probe and an energy donor; through a hybridization reaction, fluorescence resonance energy transfer is carried out between the gold nano particles and the carbon dots, and fluorescence of the detection system is quenched. After addition of adenosine, the adenosine and the aptamer complementary chain are competitively combined with the aptamer, so that energy transfer efficiency between the gold nano particles and the carbon dots is weakened; and the fluorescence of the detection system is recovered, so that based on the change of the fluorescence signal, the method achieves quantitative detection of the adenosine. The method has strong specificity and simple operation, is low in required quantity of a sample, is high in sensitivity, can be used for detecting the adenosine in a blood sample and supplies useful analysis data for clinical diagnosis on diseases.

The invention belongs to the field of composite luminescent materials and discloses a fluorescent carbon dot/mesoporous molecular sieve composite luminescent material, a preparation method of the composite luminescent material and application of the composite luminescent material in the aspect of oxygen sensing. The preparation method of the composite luminescent material comprises the following steps: (1) preparing silane functionalized fluorescent carbon dots: under a stirring condition, adding anhydrous citric acid into a silane coupling agent and reacting at a constant temperature; purifying to obtain silane functionalized fluorescent quantum dots; (2) preparing the fluorescent carbon dot/mesoporous molecular sieve composite luminescent material: under the condition of taking ethanol as a solvent, taking a mesoporous molecular sieve to react with the silane functionalized fluorescent carbon dots prepared in the step (1) and purifying to obtain the fluorescent carbon dot/mesoporous molecular sieve composite luminescent material. The preparation method is simple, and the raw materials are low in price and have no toxin; the prepared composite luminescent material has high sensitivity and selectivity, stable performance, and quick response, the emission intensity is sensitive to oxygen concentration, and the composite luminescent material is an economical type green and environment-friendly oxygen sensing material.

The invention relates to the field of fluorescence carbon nanomaterials, in particular to a high-quantum-yield eigenstate-fluorescence-adjustable carbon dot and a preparing method and application thereof. Diaminonaphthalene or a hydroxyl, carboxyl, methyl, ethyl, N,N-dimethyl and N,N-diethyl substituted ramification of the diaminonaphthalene and citric acid serve as carbon source precursors, an eigenstate fluorescence carbon dot solution can be obtained through a solvothermal method. The prepared eigenstate fluorescence carbon dot has the beneficial effects of being high in crystallization, high in surface passivation degree, even in nitrogen doping, even in size distribution and the like, and has the wide application prospect.