Method of increasing stability of aqueous solution of quantum dots - cadmium selenide nanoparticles coated with mercapto acids |
|
IPC classes for russian patent Method of increasing stability of aqueous solution of quantum dots - cadmium selenide nanoparticles coated with mercapto acids (RU 2484116):
 Polymer nanoparticles containing medium for photon up-conversion / 2479616
Polymer nanoparticles contain a medium for photon up-conversion and a stabilising agent. Said medium contains a polymer matrix having two organic components distributed therein. The first component is capable of absorbing light at a first wavelength in the range w≤λ1≤x and acts as a sensitiser in said medium. The second component is capable of emitting light at a second wavelength in the range y≤λ2≤z, where λ2≤λ1, and acts as an emitting component in said medium. The stabilising agent is selected from hydrophilic or amphiphilic polymers.
 Polymer luminescent composition for obtaining white light excited by blue light-emtting diode / 2405804
Polymer luminescent composition for obtaining white light excited by a blue light-emitting diode contains the following components, pts. wt: transparent polymer 100; photoluminescent phosphor based on garnet Y3Al5O12:Ce or Gd3Al5O12:Ce, or based on a mixture of said compounds 1.5-5.0; polyethylene wax in form of powder with particle size of 18-30 mcm 0.1-0.7; stabiliser 0.2-1.0. The transparent polymer used can be polycarbonate, polystyrene or a copolymer of styrene with acrylonitrile and butadiene. The stabiliser can be a compound from a group of sterically hindered phosphites.
 Method for synthesis of semiconductor quantum dots / 2381304
Invention relates to synthesis of nucleus- and nucleus-shell type semiconductor quantum dots through colloidal synthesis, which can be used in making different luminescent materials, as well as a base for making subminiature light-emitting diodes, white light sources, single-electron transistors, non-linear optical devices, photodetector and photovoltaic devices. The method for synthesis of semiconductor quantum dots based on chalcogenides of group II or group IV metals involves synthesis of nuclei of nanocrystals from a precursor containing chalcogen, and a precursor containing group II or IV metals, using an organic solvent and a surface modifier in form of (aminoalkyl)trialkoxysilanes. The nuclei are synthesised at constant temperature within the limits of 150 - 250°C for 15 s to 1 hour and the reaction mixture containing the nucleus of nanocrystals is further treated with UV light for 1-10 minutes and ultrasound for 5-15 minutes.
 Method of obtaining luminescent nanoparticles of cadmium sulphide, stabilised with polymer matrices / 2370517
Method is described for obtaining luminescent nanoparticles of cadmium sulphide, stabilised with polymer matrices, involving growing nanoparticles of cadmium sulphide directly in polymer matrices. A polymer compound, chosen from a series which includes polystyrene-block-polyethylene oxide, polystyrene-block-polyethylene oxide, polystyrene-block-4-vinylpyridine or polyphenylene, is dissolved, anionic surfactant is added to the obtained mixture with subsequent addition of a compound which contains cadmium cations, and then a compound which contains sulphur anions, and after growing cadmium sulphide nanoparticles excess anionic surfactant is removed.
 Method for applying protective film on surfaces of phosphor particles / 2256254
Proposed method that can be used for encapsulating phosphor particles to enhance their lighting and servicing parameters by producing continuous silicon dioxide film on their surfaces includes treatment of phosphor particles with 0.5 and 4 mass percent sols of polysilicic acid synthesized by hydrolyses of tetraethoxysilane in 0.6 - 0.8 mass percent aqueous solution of ammonia.
 Method of preparing moisture-resistant particles of electroluminescent phosphor / 2247761
Nitride coating precursor, in particular aluminum-, gallium-, or tin-containing metalloorganic nitride, is charged into reaction vessel 10a filled with electroluminescent phosphor, e.g. ZuS-Cu, and surrounded by heating means 30a using nitrogen as inert gas carrier. Precursor is passed through pipeline 32 open all over its length. Co-reagent, e.g. anhydrous ammonia is fed into lower part of vessel 12a through porous glass disk 12a. When vessel 10a is heated to 150-225°C, nitride coating precipitates on phosphor particles being in fluidized state. Phosphor bearing nonoxide coating is characterized by high brightness after 100 h use at high humidity.
The method of applying a product to protect against counterfeiting, comprising a phosphor antitoksicski / 2197512
The invention relates to methods of covert recording information, in particular to methods of recording using antistatisch phosphors, and is intended to enhance the protection of various printed materials (documents, labels, stamps, inscriptions on products and packaging and so forth) executed by way of flexography, from fakes
 The method of preparation of a suspension of phosphor / 2085568
The invention relates to fluorescent technology, in particular to methods of producing phosphor suspensions, and can be used in the production of thin-layer cathodoluminescent screens
Method of producing porous nanostructured silicon carbide / 2484017
Invention relates to inorganic chemistry and can be used in making catalyst supports, filters and electronic materials. The starting materials used are powdered silicon and detonation synthesis diamonds, which are mixed in weight ratio silicon:diamond from 2:1 to 2.4:1. The powdered mixture is then moulded into a workpiece of the required article and then heat treated at temperature of 1200-1500°C in a vacuum or inert medium.
 Method to produce hollow nanoparticles / 2484015
Invention relates to technology of nanoparticles production. The method is proposed to produce hollow nanoparticles, which consists in application of a silicon carbide coating onto a surface of carbon nanotubes by pyrolysis of methyl silane, afterwards carbon nanotubes are removed by burning.
 Method of producing carbon-containing nanoparticles / 2484014
Invention can be used in plasma chemistry and pharmacology. A vapour-liquid plasmatron is used to form a plasma jet from alcohol or aqueous solution thereof. The plasma jet is fed into a volume of water by dipping the nozzle of the plasmatron 10-20 mm into the water perpendicular to the water surface.
 Method of producing fullerene-polysulphonic acid / 2484012
Invention relates to chemical industry and medicine and can be used in producing concrete plasticisers, microbiocides with anti-HIV properties which are not cytotoxic and modifiers of epoxy composites. Fullerene-polysulphonic acid is a water- and alcohol-soluble product of reaction of coal tar and coal tar pitch with sulphuric acid with concentration of at least 80%. Unreacted sulphuric acid formed when treating sulphonic acid and unreacted aromatic hydrocarbons are successively washed off with toluene, carbon tetrachloride and acetone to pH 6.5-7.0. Fullerene-polysulphonic acid is then extracted with ethyl alcohol in Soxhlet apparatus. Ethyl alcohol is distilled from the alcohol solution of fullerene-polysulphonic acid to dry residue.
Low-temperature chemical method of producing fullerene / 2484011
Invention relates to chemistry and nanotechnology. The method of producing fullerene C84 involves treating coal tar or coal tar pitch with sulphuric acid, washing off unreacted sulphuric acid, the formed sulphonic acids and hydroxyl compounds with water, and the unreacted aromatic hydrocarbons successively with carbon tetrachloride and acetone. Fullerene is then extracted with toluene or ortho-xylene and the toluene or ortho-xylene are distilled from the obtained extract until achieving a moist state of fullerene residue which is dried at temperature of 60-70°C. The obtained fullerene C84 is soluble in benzene, toluene and ortho-xylene.
 Method of producing cobalt nano-sized powders / 2483841
Invention relates to powder metallurgy. Proposed method comprises thermal decomposition of cobalt-bearing precursor in hydrocarbon oil, its settling, its separation and flushing with hexane. Said cobalt-bearing precursor represents an α-modification of cobalt hydroxide intercalated by sodium dodecyl sulfate. Decomposition is performed for 10-30 hours at 400°C to obtain the product stabilised by carbon film to be dried at 80°C.
 Method of producing lubricant composition / 2483101
Two electrodes are placed in a defined volume of hydrocarbon oil (petroleum or synthetic), said electrodes being made from non-magnetic conducting material with a finite resistance with a gap between the electrodes, to each of which high-voltage pulses are transmitted, having amplitude which provides breakdown between the electrodes. The repetition frequency of the high-voltage pulses is set such that discharge current lies in the range from a half-period to several periods.
 Method of synthesizing fullerene mix in plasma at barometric pressure / 2483020
Invention relates to plasma synthesis of nanomaterials. Fullerene mix is produced in carbon-helium plasma formed by arc discharge at barometric pressure in plasma chemical reactor chamber using one vertical and even number of identical horizontal electrodes. Note here that low-frequency modulation of arc discharge power is created by reducing voltage at low-frequency arc discharge to comply with acoustic resonance in plasma chemical reactor chamber.
 Method of producing photonic-crystal structures based on metal oxide materials / 2482063
Invention relates to opto- and microelectronics and can be used to make opal-like structures. The method of producing photonic-crystal structures based on metal oxide materials involves filling a template consisting of monodispersed micropheres of polystyrene, solutions of metal-containing precursors, followed by annealing the structure on air at temperature of 450-550°C for 8-10 hours. The precursors from which the structure is formed are saturated alcohol solutions of tin dichloride SnCl2·2H2O or zinc nitrate Zn(NO3)2·2H2O.
 Method of producing wide-pore gamma-aluminium oxide / 2482061
Invention relates to chemistry. Wide-pore aluminium oxide in gamma-form is obtained by depositing aluminium hydroxide from aluminium nitrate solution with aqueous ammonia solution at pH 7±0.1, temperature of 70±2°C and suspension curing time of 3-5 hours. A paste with 58-66% moisture is formed. The paste is obtained by mixing (66-70)% moist precipitate of aluminium hydroxide and a powder, which is dried in a spray drier, of (30-34)% moist precipitate of aluminium hydroxide prepared in form of a suspension. Drying and firing are carried out after moulding.
Method of producing porous nanostructured silicon carbide / 2484017
Invention relates to inorganic chemistry and can be used in making catalyst supports, filters and electronic materials. The starting materials used are powdered silicon and detonation synthesis diamonds, which are mixed in weight ratio silicon:diamond from 2:1 to 2.4:1. The powdered mixture is then moulded into a workpiece of the required article and then heat treated at temperature of 1200-1500°C in a vacuum or inert medium.
|
FIELD: chemistry. SUBSTANCE: aqueous solution of quantum dots based on cadmium selenide coated with mercapto acids is stabilised by adding sodium sulphite until achieving its concentration of 0.02-0.2 mol/l in the solution. EFFECT: high stability of aqueous solution of quantum dots while preserving luminescence brightness, hydrodynamic diameter and active groups of the quantum dots. 2 dwg
The invention relates to analytical chemistry and can be used when working with aqueous solutions of quantum dots of cadmium selenide, covered mercaptopropionate, to stabilize them. Known composition for the stabilization of aqueous quantum dots containing toorganise (for example, mercaptopropionate) acid (Warren .W. Chan, S. Nie, Quantum Dot Bioconjugates for Ultrasensitive Nonisotopic Detection, Science 281, 2016 (1998); J.Aldana, Y.A.Wang, and X.Peng Photochemical Instability of CdSe Nanocrystals Coated by Hydrophilic Thiols J. Am. Chem. Soc., 2001, 123 (36), PP 8844-8850). The current structure allows for greater stability of solutions of quantum dots (CT) due to the formation on their surface coating of mercaptopropionic (mercaptopropionic acid - IPC). Aqueous solutions of CT, covered only IPC stable for 2-3 days, and the brightness decreases after 25 hours at room temperature. The main disadvantage of known composition for the stabilization of the CT mercaptopropionic acid is its short duration of action. Low stability over time is related to the fact that tirinya group, through which mercaptopropionate (mercaptoacetate) acid is bound with metal atoms on the surface of quantum dots, easily undergo oxidation in the light. In tirinya groups are oxidized to disulfide groups; sulfur atoms in the structure of disulfide groups is of looking is not associated with the metal atoms. As a result of oxidation stabilizer nanocrystals are coagulated with each other and precipitate. There is a method of stabilizing an aqueous solution of quantum dots coated mercaptoacetate using polyelectrolytes, which form a dense layer of ligands around the CT due to the electrostatic interaction (Zhang, S., Yu J., Li X., Tian W. Photoluminescence properties of mercaptocarboxylic acid-stabilized CdSe nanoparticles covered with polyelectrolyte. Nanotechnology. 2004. V.15. No. 8. R-1112). In aqueous solutions of CT, covered with mercaptoacetate, are negatively charged due to deprotonation of carboxylic groups. Adding cationic polyelectrolytes is linking them with quantum dots. Due to the formation of a dense coating layer the access of oxygen to the surface of the CT is difficult, which greatly increases the stability of aqueous solutions of CT. The experimental data, the brightness of aqueous solutions is not reduced after 16 days. However, the polyelectrolytes form an additional layer around the CT, which leads to a change of the hydrodynamic radius CT. There is a method for stabilizing an aqueous solution of quantum dots on the basis of cadmium selenide coated mercaptoacetate by application of chemically modified protein is bovine serum albumin (BSA). First BSA treated with sodium borohydride, the majority of disulfide bonds in ostanavlivajutsja to tylnej groups, through which is the binding of the protein with the surface of the CT. Due to the high molecular weight and branched structure of the protein effectively passivates the surface of the CT and significantly improves the stability of their solutions. According to (Gao X, Chan WC, Nie S. Quantum-dot nanocrystals for ultrasensitive biological labeling and multicolor optical encoding J.Biomed. Opt. 2002 7 (4) p.532-537) aqueous solutions of CT, covered with mercaptoacetate and modified protein BSA, stable for more than two years. The size of CT increases on average by 4 nm. The disadvantages of this method are the increased hydrodynamic radius of the quantum dots, as well as the likelihood of nonspecific interactions of such systems due to the reactive groups of the protein. This method is adopted for the prototype. The technical result of the invention is to increase the stability of solutions of quantum dots of cadmium selenide coated mercaptoacetate, while maintaining the hydrodynamic diameter and active groups of quantum dots without changes. The claimed technical result is achieved by the fact that for the stabilization of aqueous quantum dots of cadmium selenide containing toorganise acid, according to the decision impose additional sodium sulfite to its concentration in a solution of 0.02 to 0.2 mol/L. The invention is illustrated by drawings, where figure 1. presents the dependence of the article the stability of aqueous solutions of nanocrystals of cadmium selenide on the concentration of sodium sulfite (mol/l); figure 2 presents time-resolved emission spectra of a solution of nanocrystals of cadmium selenide with different concentrations of sodium sulfite: 1 - without sodium sulfite, 2 - 0.02 mol/l, 3 - 0.1 mol/l, 4 - 0.5 mol/l sodium sulfite. In the case of the preparation of quantum dots in an organic environment, they are transferred from the organic phase in water using mercaptopropionic, then cleaned of excess reagents. Then the titanium carbide powder is dissolved in a buffered aqueous solution with a pH>7 (for example, phosphate-saline buffer (FSB), pH 7.4, containing 0.003 mol/l KN2RHO4, 0.02 mol/l Na2HPO4, 0.3 mol/l NaCl, 0.002 mol/l KCl), and add sodium sulfite to its concentration in a solution of 0.02-0.2 mol/l option of adding sodium sulfite in the buffer solution at the stage of its preparation to dissolve therein quantum dots. In the case of the preparation of quantum dots in the aquatic environment they are cleaned, and then in the buffer aqueous solution, intended for dissolution CT (buffer solutions with pH>7, such as, for example, the FSB), add sodium sulfite to its concentration in the buffer solution of 0.02 to 0.2 mol/L. Increase the stability of aqueous solutions of quantum dots stabilized by Tiquisate is due to the use of sodium sulfite, which is able to chemically bind dissolved oxygen, thereby preventing oxidation tylenol gr is PPI. The increase in colloidal stability is achieved by the introduction of low-molecular substances, not included in the covering layer of the CT, and therefore, the hydrodynamic diameter and active group of quantum dots will remain unchanged. The size of quantum dots does not change, and the nonspecific interaction excluded because only one reactive carboxyl group remains. Figure 1 presents the results of experimental verification of the effect of sodium sulfite on the colloidal stability of an aqueous solution of nanocrystals of cadmium selenide. It is seen that in the absence of sodium sulfite solution loses its colloidal stability and CT precipitate after 4 days, at a concentration of 0.02 mol/l after 7 days, at a concentration of 0.1 mol/l to 13 days, at a concentration of 0.5 mol/l - 16 days. Thus, the concentration of sodium sulfite 0.02 mol/l gives almost a twofold increase the stability of the aqueous solution of quantum dots of cadmium selenide. Figure 2 shows that by increasing the concentration of sodium sulfite reduces the intensity of luminescence, so it is not feasible to stabilize to use more concentration of 0.2 mol/L. Method of stabilizing an aqueous solution of quantum dots on the basis of cadmium selenide coated mercaptoacetate, characterized in that the solution of quantum dots enter unfit sodium to its concentration in a solution of 0.02 to 0.2 mol/L.
|
