131 results about "Carbon nanodots" patented technology

The invention discloses a carbon nano-dot, and a preparation method and an application thereof, and solves a problem that the application of present nano-dots is restricted because of high preparation cost and easy fluorescent quenching appearance of an aggregate state. According to the invention, the carbon nano-dot having a high fluorescence quantum efficiency is prepared through adopting a polycarboxyl or polyhydroxy contained organic compound, or an amino acid as a raw material, and urea as a surface passivation modification agent, and through a microwave process, and a carbon nano-dot fluorescent ink is prepared through using the carbon nano-dot. The preparation method disclosed in the invention has the advantages of simplicity, low cost and convenient large-scale production; the fluorescent quenching of the prepared carbon nano-dot on the surface of a biological product does not appear, and the highest fluorescence quantum efficiency is 42%; and the prepared carbon nano-dot fluorescent ink is nontoxic, does not generate a precipitate after long-time dispose, and can be applied to the biological imaging field, the biological product identification field, the information storage field, the information encryption field, the false proof field, the illumination display field, the photovoltaic device field and the like.

The invention discloses an application of carbon nanodots as a water-soluble ratiometric fluorescent probe and solves the problems that the existing ratiometric fluorescent probes are high in preparation cost, poor in luminescent stability and provided with potential toxicity. According to the application, the carbon nanodots are dissolved in a solution to be measured, an excitation wavelength is fixed at 360-400nm,the solution to be measured dissolved with the carbon nanodots is subjected to fluorescence spectrum detection at a fixed temperature, intensities of a blue maximum fluorescence-emission peak and a green maximum fluorescence-emission peak are measured, the ratios of the blue maximum fluorescence-emission peak intensity and the green maximum fluorescence-emission peak intensity are calculated, so that the detection of the objective to be measured is achieved. The application has the advantages of being low in cost, good in luminescent stability, non-toxic, high in sensitivity and capable of achieving detection for temperature, pH of water solution, ethanol concentration in ethanol water and Fe3+ concentration in Fe3+-containing neutral water solution simply, accurately and quickly.

The invention discloses a multicolor luminous carbon nanodot as well as a preparation method and an application thereof, belonging to the field of nanomaterial science and solving the technical problems that the emitted light peak position of a carbon nanodot generates red shift and the strength is weakened with increase of wavelength of excited light and a preparation method of the carbon nanodot is high in cost, complex to operate, time-consuming and labor-consuming in the prior art. According to the preparation method, with a polycarboxylic or polyhydric organic compound or an amino acid as a carbon source and long-chained organic diamine as a surface passivation modifier, the multicolor luminous carbon nanodot is prepared by the steps of low-temperature pyrolysis, precipitation washing, dialysis separation and freeze drying. The preparation method of the multicolor luminous carbon nanodot is simple, low in cost and can be conveniently put into large-scale production; the prepared carbon nanodot is at a solid state, is convenient to store, has high fluorescence quantum efficiency and good biocompatibility, can respectively emit strong green light, orange light and red light under the excitation of blue light, green light and yellow light, and can be used as a bioluminescence probe and an optical imaging marker.

The invention provides a preparation method for carbon dots. The preparation method comprises the steps: mixing citric acid and urea in a solvent, and then, carrying out heating, so as to obtain a reaction solution; and carrying out centrifugal separation on the reaction solution, so as to obtain precipitates, i.e., the carbon dots, wherein the solvent is one or a mixture of two of water, glycerine and dimethylformamide. According to method, visible-light-all-waveband-luminescent carbon dots are prepared through adopting different solvents, and thus, the carbon-dot composite material provided by the invention can emit light in all wave band of visible light, particularly, white-light carbon-dot composite materials of different color coordinates and color temperatures can be obtained by adopting the carbon dots of different colors. Furthermore, the carbon-dot composite material provided by the invention employs silicon dioxide as a dispersion matrix, so that gathered induced fluorescence quenching can be inhibited, and the composite material has relatively high quantum efficiency. The invention further provides the preparation method for the carbon dots, the carbon-dot composite material, a preparation method therefor and a luminescent LED (Light Emitting Diode).

The invention provides a preparation method of a carbon nano dot with adjustable light emission in visible-region whole spectral coverage. The preparation method comprises the following steps of dissolving citric acid and urea in a reactive solvent to carry out a solvothermal reaction, so as to obtain the carbon nano dot, wherein the reactive solvent comprises one or multiple of protonic solvents which are mutually soluble with water and / or non-protonic solvents which are mutually soluble with the water and the water; the mixing ratio of the water to the one or the multiple of the protonic solvents which are mutually soluble with the water and / or the non-protonic solvents which are mutually soluble with the water is 0 to 100 percent; and the mixing ratio of the protonic solvents which are mutually soluble with the water to the non-protonic solvents which are mutually soluble with the water is 0 to 100 percent. By using the preparation method, in a solvothermal condition, through regulating the mixing ratio of the water to the protonic solvents and the non-protonic solvents, which can be mutually soluble with the water, the carbon nano dot with the adjustable light emission in the visible-region whole spectral coverage can be prepared. The problem that a light-emitting band gap of the carbon nano dot is difficult to regulate and control is solved.

The invention relates to a preparation method of an aerogel composite adsorbent for efficient removal of indoor formaldehyde. The method specifically includes the steps of: adding graphite oxide into an aqueous solution, and conducting uniform ultrasonic dispersion to obtain an graphene oxide aqueous solution; adding graphene carbon nanodots into the prepared graphene oxide aqueous solution, conducting uniform ultrasonic dispersion, then adding a reducing agent and ammonia water in order, and stirring the mixture fully to obtain a mixed solution; soaking a sponge into the mixed solution, performing sealing, then placing the product in constant temperature water bath to carry out water bath reaction; at the end of the water bath reaction, removing redundant solution, and carrying out freeze drying so as to obtain the adsorbent. Compared with the prior art, the preparation method provided by the invention is simple, mild, green and environment-friendly, and has no secondary pollution, the raw materials are easily available, and the prepared aerogel composite material has significantly improved formaldehyde adsorption performance uo to 22.81mg / g, and the longest penetration time is 7500min / g. Thus, the aerogel composite adsorbent has good application prospects.

The invention discloses preparation of red fluorescent carbon nanodots, and a method used for detecting ferric ions and ascorbic acid, and belongs to the field of metal ion detection. According to the preparation, citric acid, thiourea, and acetone are taken as raw materials, are delivered into a hydro-thermal reaction kettle, and are reacted for 8h at 160 DEG C so as to obtain the red fluorescent carbon nanodots. The method comprises following steps: a carbon nanodot solution is prepared; ferric ion solutions of different concentrations are added, and the change of the fluorescence intensity is detected using a fluorospectro photometer; a curve used for representing the change of fluorescence intensity with ferric ion concentration is drawn, and fitting is carried out so as to obtain a fitting formula; reduction of ferric irons can be realized with ascorbic acid, so that ascorbic acid solutions of different concentrations are added to recovery fluorescence, a curve used for representing the change of fluorescence intensity with ascorbic acid concentration is drawn, and fitting is carried out. The method can be used for detecting the concentrations of iron ions and ascorbic acid, and is simple and convenient.

The invention discloses an ultra carbon nanodot with high near-infrared absorption performance, a preparing method thereof and an application thereof, and belongs to the technical field of carbon nanometer materials. The technical problems that the absorbing and the photothermal conversion efficiency of a carbon nanodot in the prior art in the near-infrared region are low are solved. The ultra carbon nanodot is composed of carbon nanodot bodies with electropositivity functional groups and electronegativity functional groups on the surfaces at the same time in an automatic assembling mode, absorption peaks exist in the spectral range of 70nm to 1,000 nm, and the photothermal conversion efficiency in the spectral range is 30% to 65%. The ultra carbon nanodot has the advantages of being small in size, high in water solubility and good in biocompatibility, further has high near-infrared absorption performance and efficient near-infrared photothermal conversion performance, can serve as a near-infrared photothermal conversion nanometer material and can be applied to the energy conversion field and the medical field.

The invention discloses a method for modifying a three-dimensional graphene material with carbon nano-dots. The method comprises the following steps: functionalizing graphene oxide with a macrocyclic compound, adding a carbonate solution to form a carbonate-containing macrocyclic compound and graphene oxide super-molecular sol system, carrying out freeze drying treatment, and carrying out multi-stage heating heat treatment to form a three-dimensional structure, wherein carbonate is adopted as a pore forming agent to prevent agglomeration of graphene. Formation of the super-molecular system prevents agglomeration of graphene oxide in the reduction process, the macrocyclic compound decomposes to anchor ordered carbon nano-dots to reduced graphene oxide nano-sheets in an in-situ manner in the calcining process, graphene sheets are separated by the carbon nano-dots, and graphene interlamellar spacing is increased; and a carbon nano-dot modified three-dimensional graphene material prepared through the method has a large specific surface, the three-dimensional structure is in favor of de-intercalating electrolyte ions in the graphene interlayer, and high specific capacitance can be obtained by using the carbon nano-dot modified three-dimensional graphene material in a super capacitor electrode material.

The present invention relates to the formulation of nanofluids including carbon dot nanoparticles with particle sizes of 10 nm or less and base fluid. The term “carbon dot nanoparticles” means one or any combination of carbon quantum dots, graphene quantum dots, graphene nanodots, graphene oxide nanodots, carbon nanotubes dots, and carbon nanostructures whose specifications are consistent with those cited in the invention background section in detail. The nanofluid of the present invention is economical and environmentally friendly. Moreover, the nanofluid composition of the invention has suitable stability and capability of heat transfer required by industry.

The invention provides a method for preparing fluorescent carbon nanodots through one-step hydrothermal carbonization by taking kelp as a carbon source. The method comprises the following steps: 1) cleaning, slicing, baking and grinding fresh kelp, and sieving to obtain powder; 2) weighing and dispersing a certain amount of kelp powder in ethanol, stirring to obtain paste, putting the paste in an autoclave, and reacting for a period of time at high temperature; and 3) dispersing the product in ethanol, carrying out suction filtration, solvent rotary evaporation, and centrifugal separation to obtain precipitates, and freeze-drying the precipitates to obtain the carbon nanodots. The method provided by the invention is simple in operation, the cost is low, and the raw materials are easy to obtain; and the prepared carbon nanodots have excellent fluorescent properties and good biocompatibility and are expected to be widely applied to important fields, such as chemical sensing, biological analysis, environmental monitoring, photocatalysis, biological imaging and photoelectric conversion.

The invention discloses a pure-organic long-afterglow composite material and a preparation method thereof, belongs to the technical field of luminescent materials and is used for solving the problems that the preparation process of a long-afterglow luminescent material is complex, potential toxicity exists in the preparation process, and preparation raw materials are scarce in the prior art. The preparation method comprises the following steps of pyrolyzing ethylene diamine tetraacetic acid disodium for 2-4 hours at 200-400 DEG C in inert atmosphere so as to obtain black fluffy solids, carrying out ultrasonic dissolving on the black fluffy solids, carrying out centrifuging to remove black precipitates, taking an upper-layer tan clear solution as a water solution of carbon nanodots, finally adequately mixing the water solution of the carbon nanodots with a polyvinyl alcohol water solution, and drying to obtain the pure-organic long-afterglow composite material. The pure-organic long-afterglow composite material has the advantages that the afterglow decay time can reach multiple seconds, and the material is non-toxic, is good in biocompatibility and can be applied to the field of biological medicines.

The invention discloses a carbon nanodot-modified bismuth tungstate photocatalyst and application thereof, belonging to the technical field of photocatalytic oxidation. A preparation method for the bismuth tungstate photocatalyst comprises the following steps: preparing a sodium tungstate precursor solution A from a sodium tungstate dihydrate and deionized water, and preparing a bismuth nitrate precursor solution B from bismuth nitrate pentahydrate and dilute nitric acid solution; mixing the precursor solution A with the precursor solution B, carrying out a hydrothermal reaction at 100-250 DEGC, washing a precipitate with deionized water after completion of the reaction, drying the precipitate, then calcining the precipitate at 400-520 DEG C, and performing grinding to obtain bismuth tungstate powder; dissolving an ethylenediamine solution and a citric acid monohydrate in deionized water to prepare a carbon nanodot precursor solution, subjecting the carbon nanodot precursor solution to a hydrothermal reaction at 100-300 DEG C, carrying out filtering to obtain a carbon nanodot solution, dropwise adding the carbon nanodot solution into the bismuth tungstate powder, and carrying outmixing, drying and grinding so as to obtain the carbon nanodot-modified bismuth tungstate photocatalyst. The carbon nanodot-modified bismuth tungstate photocatalyst has excellent ability of photocatalytic oxidation of organic pollutants, and can be used for photocatalytic oxidation of organic pollutants such as rhodamine B and phenol.

In allusion to preparation complexity and poor water solubility of an Al<3+> ratiometric fluorescent probe in the prior art, the invention provides a preparation method of bifluorescent carbon nanodots and an application of the prepared bifluorescent carbon nanodots used as an Al<3+> ratiometric fluorescent probe. According to the invention, a green product Avena nuda is used as a raw material to prepare the bifluorescent (347nm and 428nm) carbon nanodots with good resolution by a microwave method. The preparation method is simple and has low cost. The prepared bifluorescent carbon nanodots which are used as the Al<3+> ratiometric fluorescent probe have characteristics of good selectivity and high sensitivity, and can be used to rapidly detect the concentration of Al<3+> in an aqueous solution containing Al<3+>.

The invention discloses carbon nanodots with optical excitation active oxygen generating performance and a preparation method thereof. The preparation method of carbon nanodots with optical excitationactive oxygen generating performance belongs to the technical field of preparation of carbon nano materaisl (carbon dots). The preparation method comprises the following steps: preparing a carbondotaqueous solution at 60 DEG C by means of a mixed solution of dopamine and 3-aminopropyl triethoxy silane; and carrying out dialysis and purification to obtain silicon-doped carbon nanodots. The carbonnanodots with optical excitation active oxygen generating performance uniform and high in fluorescence intensity can be synthesized in a mesotherm condition, and have an important application prospect in bio-imaging and sensing. The synthetic method is simple and low in cost and can be finished in a common lab.

The invention discloses a one-step method for green synthesis of nitrogen-doped fluorescent carbon nanodots, and belongs to the technical field of synthesis of fluorescent carbon nanomaterials. The one-step method for green synthesis of nitrogen-doped fluorescent carbon nanodots comprises the following steps: dissolving maleic acid in distilled water, adding ethidene diamine, trihydroxymethyl aminomethane or melamine, and carrying out ultrasonic treatment to uniformly dissolve so as to obtain a colorless transparent solution; transferring the colorless transparent solution into a hydrothermal reaction kettle to heat at 170-200 DEG C for 12-18 hours and naturally cooling to the room temperature to obtain a sepia solution; carrying out suction filtration by using a filter membrane with a pore diameter of 0.1 micron to obtain a nitrogen-doped fluorescent carbon nanodot solution. The one-step method provided by the invention is simple to operate, mild in synthesis condition, less in raw material dosage, relatively low in comprehensive cost, green, environment-friendly and easy to produce in a large scale.

The invention discloses an ascorbic acid carbon nanodot fluorescent probe, a preparation method and application thereof. The preparation method comprises the following steps: S1, adding polyethyleneimine into a reaction kettle containing an ascorbic acid solution, performing sealing, and then performing heating to carry out a reaction; S2, cooling the solution after the completion of the reactionin S1 to be room temperature to obtain a brown liquid, and performing membrane filtration on the solution; S3, dialyzing the solution subjected to the membrane filtration in S2; and S4, performing freeze-drying on the dialyzed solution in S3 to obtain the ascorbic acid carbon nanodot fluorescent probe. The probe is sensitive and rapid to the response of mercury ions, a linear relationship betweenthe fluorescence quenching intensity and the mercury ion concentration is established, the quantitative detection of mercury ions is realized, and the detection limit is 22 nM. In addition, the probehas high selectivity to mercury ions, the stability is good, the probe can be preserved and used for a long term, the synthesis is simple, and thus the probe is beneficial to commercialized popularization and application.

The invention relates to a preparation method for a garcinia mangostana-based carbon nanodot and application of the carbon nanodot as a fluorescent probe to detecting ferric ions, and aims to solve the technical problem that an existing preparation method of the carbon nanodot is time-consuming. The preparation method of the carbon nanodot comprises the following steps: putting pulp of garcinia mangostana into a crucible for roasting and drying to obtain a solid; then, heating the solid in an electrothermal furnace, and cooling and crushing after the solid turns yellow brown from white in color to obtain yellow brown powder; dissolving the yellow brown powder with ultrapure water, magnetically stirring, performing ultrasonic treatment and centrifugally extracting supernate; filtering and dialyzing the supernate, and drying and crushing obtained carbon nanodot solution in vacuum to obtain carbon nanodot powder (MCDs). The carbon nanodot powder can serve as the fluorescent probe to interact with the ferric ions, so that fluorescence of the MCDs is quenched and a MCDs-Fe<3+> compound is formed, and therefore, detection on the ferric ions is realized. The fluorescent probe can be used in the field of fluorescent sensors.

The present invention relates to a method for preparingg carbon nanodots based on chemical cutting, comprising dispersing waste carbon source materials in a mixed concentrated acid which plays a "chemical scissors" role during oxidation and cuts two-dimensional turbostratic structures of fiber materials into fluorescence carbon nanodots with small dimensions. Color of the carbon nanodots is adjusted by changing the reaction time and the temperature, and finally about 8-12nm carbon nanodots can be obtained after dilution, alkali neutralization and dialysis bag interception and separation. Compared with the prior art, the method for preparing carbon nanodots based on chemical cutting is simple in process, can obtain the carbon nanodots with small dimensions by controlling reaction parameters, and does not need special equipment and instruments. The carbon nanodots have stable fluorescence property and good water solubility, and present a multi-colored fluorescent effect.

The invention provides a solid luminescent carbon nanodot. The solid luminescent carbon nanodot is prepared through a solvothermal method with citric acid and a polyamine polymer as the raw materials.The invention further provides a preparing method of the solid luminescent carbon nanodot. The solid luminescent carbon nanodot is prepared through the one-step solvothermal method with the citric acid and the polyamine polymer as the reaction raw materials. The carbon nanodot is a solid luminescent pure carbon nanodot, and the carbon nanodot can emit bright fluorescent light without any dispersing substrate under the excitation of blue light.

The invention provides a high-stability carbon nanometer fluorescence dye. The high-stability carbon nanometer fluorescence dye is coated on the surface of a conventional luminescent material, can be used for changing a luminescent spectrum and comprises a carbon nano-dot fluorescent material, a thinning agent, a binding agent and a fluorescent dyeing matter. The high-stability carbon nanometer fluorescence dye is characterized in that the carbon nano-dot fluorescent material is mixed with the thinning agent to form a fluorescent solution containing the carbon nano-dot fluorescent material; the fluorescent solution is uniformly mixed with the binding agent to form a fluorescent binding agent; and the fluorescent binding agent is combined with the fluorescent material. The high-stability carbon nanometer fluorescence dye provided by the invention has the characteristics of transparency, stability, no toxicity, environmental protection, low cost, simplicity in use and the like. The high-stability carbon nanometer fluorescence dye can be widely applied to the fields such as color long afterglow, light emitting display, light conversion agents, anti-fake fluorescent materials and various coatings.

The invention discloses a preparation and regulation method of high-chromaticness fluorescent carbon nanodots, and relates to the technical field of luminescent nanomaterials. The method comprises thefollowing steps: dissolving a diamine compound and a phenol compound in a solvent A for mixing, loading the mixture into a reaction kettle, and controlling the temperature at 100 to 300 DEG C to perform a solvothermal reaction for 2 to 48 hours to obtain high-chromaticness fluorescent carbon nanodots; then purifying. The CIE chromaticity coordinate of the high-chromaticness fluorescent carbon nanodots is (0.33, 0.33), the CRI value is up to 93, the CCT is 5453K, standard white light emission is realized, the fluorescent spectrum range is in a coverage range of 380 to 700 nm, and the matchingdegree with a standard sunlight spectrum can be up to 85 to 114 percent.

The invention discloses a carbon nanoscroll, a preparation method and application thereof, and a carbon nanobelt. The preparation method of thecarbon nanoscrollcomprises the steps that carbon nanodotsare subjected to a solvothermal reaction in a polar aprotic solvent to form the carbon nanoscroll, wherein the surfaces of the carbon nanodots are provided with active sites, and the active sites comprise one or more of hydroxyl, carboxyl and amino. The preparation method comprises the following steps:solvothermal reaction is carried out on carbon nanodots; active sites (hydroxyl, carboxyl, amino, carbonyl and the like) on the surfaces of the carbon nanodots are subjected to dehydration fusion growth among particles in the polar aprotic solvent; and at last rolling is realized to form the carbon nanoscroll. The invention further provides a new method for preparing the carbon nanoscroll, and the carbon nanoscroll has the characteristics of near-infrared absorption and near-infrared luminescence relative to carbon nanodots, and also has good photothermal conversion performance at the same time. The preparation method is simple, low in cost and easy for large-scale batch preparation, andhas a good application prospect in the fields of photo-thermal conversion materials, photo-thermal therapy, drug carriers and the like.

A method for preparing photoluminescent carbon nanodots includes preparing and drying a sample, ashing the sample, extracting the ashed sample with solvent, filtering the extracted sample, concentrating the filtered sample, dissolving the sample in water, and freeze-drying the dissolved sample. The sample is preferably a food waste residue or animal excrement.

The invention discloses a nitrogen-doped carbon nanodot / magnetic metallic oxide composite nanofiber material, a preparation method and application thereof, and belongs to the technical field of controllable preparation of metallic oxide based composite nano-materials. An electrospinning technique is utilized to be combined with air atmosphere calcination, in-situ oxidizing polymerization and an inert atmosphere high temperature calcination technique to prepare the nitrogen-doped carbon nanodot / magnetic metallic oxide composite nanofiber material. The whole morphology of the composite material is fibrous, the surface of fiber is decorated with nitrogen-doped carbon nanodots of 5 to 15nm. The method is simple and practical and has good repeatability. A nitrogen-doped carbon nanodot / magnetic metallic oxide composite nanofiber zymoid catalyst prepared through the method has the advantages of simple preparation method, high activity and good catalytic activity on zymoid catalytic oxidizing reaction. The prepared composite nanofiber material has important significance on promoting development and commercialization processes of the zymoid catalyst.

The invention discloses a synthetic method of chitosan biomass-derived high-yield nitrogen-doped fluorescent carbon nanodots and belongs to the field of biomass carbon material synthetic technology. The invention aims to solve the problem of low synthetic yield of biomass-derived fluorescent carbon nanodots existing in the prior art. The synthetic method of the invention comprises the following steps: dissolving a chitosan derivative containing unsaturated double bond in ultrapure water, carrying out hydrothermal carbonization and successively carrying out centrifugal separation, dialysis and freeze-drying treatment so as to obtain solid nitrogen-doped fluorescent carbon nanodots. The dimension of the prepared nitrogen-doped carbon nanodots is 3-5nm. The surface of the carbon nanodots contains amino group, carboxyl group and hydroxyl group. Quantum efficiency is 20-30%. The chitosan containing unsaturated double bond is used as a carbon source, and high-yield (46%) synthesis of the chitosan biomass-derived nitrogen-doped fluorescent carbon nanodots is realized. The method of the invention is expected to realize preparation of the carbon nanodots in macroscopic quantity.

The invention provides composite film for achieving efficient photoinduction electron transfer in a visible region, a preparation method and application, and belongs to the field of nanometer material science. The composite film is characterized in that transparent conductive oxide film serves as an electron extraction layer, citric acid serves as a carbon source, urea serves as a nitrogen source, nitrogen-doped carbon nanodots synthesized according to a microwave method serve as a photosensitive layer, and the photosensitive layer is compounded with a titanium dioxide electron separation layer of a nanometer mesoporous structure, so that the composite film is prepared. According to the composite film, with the help of oxygen molecules in air, efficient photoinduction charge separation from the carbon nanodots to titanium dioxide can be achieved, and the composite film can be applied to air purification and preparation of high-performance carbon-based solar cells, also shows the good dye light degradation characteristic in water, and can be used for water pollution control.

The present invention discloses a preparation technique of composite nanodots based on carbon nanodots, and their use in the field of fluorescent imaging, wherein, the main components of the composition are carbon nanodots, which are material with superior biocompatibility characteristics, and supporting component is methylene blue, and particle diameter range is 100-500 nanometers, and the zeta potential is −35 to 10 millivolts. The above said techniques for preparation of composite nanodots are safe, quick and simple, low cost, and easy to perform for industrialized production. Composite carbon nanodots have good biocompatibility and safety, high fluorescence imaging sensitivity, and they are promising in gaining wider use in the fields of biomedical imaging, targeting diagnosis and therapy, drug screening and optimization, and in vivo labelling and tracing, and have potential value in personalized medicine.

The invention discloses pure carbon nanodots, a preparation method thereof and an LED light source. The preparation method of the pure carbon nanodots disclosed by the invention comprises the following steps: adding an inorganic salt, a polyhydroxy compound and an amino compound into deionized water, performing dissolving, and performing vacuum heating to obtain the pure carbon nanodots, wherein amass ratio of the inorganic salt to the polyhydroxy compound to the amino compound is (0.1-2):(0.1-5):1. The technical scheme disclosed by the invention has simple experimental operation, low risk and good experimental repeatability, and can be used for mass production; and meanwhile, the obtained carbon nanodots have high luminous intensity.