71results about How to "Response recovery time is short" patented technology

The invention relates to a preparation method of a low-concentration acetone gas sensor, and belongs to the technical field of preparation processes of metal oxide semiconductor gas sensors. The gas sensor is mainly characterized in that double layers of nanometer sensitive materials with porous structures are coated on the surface of an aluminum oxide ceramic pipe, an inner substrate material is Pt doped nanometer porous SnO2, and an outer sensitizing material is nanometer porous Al2O3. After a gas-sensitive element coating the Pt doped porous SnO2 substrate material is roasted for 2 hours at the temperature of 500 DEG C, the porous Al2O3 sensitizing material is uniformly coated on the outer surface of the gas-sensitive element, and the gas-sensitive element is welded according to a thick-film semiconductor gas-sensitive element manufacturing process after dried at the indoor temperature (comprises a platinum wire and a nickel-cadmium heating wire in a cavity of a ceramic pipe), aged and packaged to make the low-concentration acetone gas sensor. The made sensor has the advantages of low detection limit, fast response and recovery, fine stability and the like for acetone gas.

The invention discloses a preparation method of an indium oxide-based gas-sensitive material with a three-dimensional hollow multi-stage structure and an application thereof. The material is prepared by taking an indium salt, deionized water and glycerol as solvents, taking ethylene diamine as an indium ion ligand and taking hexadecyl trimethyl ammonium bromide as a surfactant with a hydro-thermal synthesis method, has an indium oxide nanosheet self-assembly three-dimensional flower-shaped hollow multi-stage structure, and is 0.5-3 mum in diameter. The preparation method has a simple process and low cost, is environmentally-friendly, and is suitable for large-scale production. As proved by an experiment for manufacturing a gas-sensitive sensor by using the material prepared with the method, the material has very high sensitivity to acetone and toluene, the minimum detection limit can be up to grade ppb, and a device has very short response time and restoration time, high stability and high selectivity and can be applied to gas-sensitive sensors of acetone and toluene.

The invention discloses a preparation method of an ethanol gas sensor component having an ultrafast response recovery property. In the preparation method, LaFexO3 nano particles in non-stoichiometric ratio prepared through a sol-gel method are employed as a working substance to prepare a beside-heating-type ceramic tube gas sensor component. By means of reduction of a relative element ratio of iron to lanthanum in a precursor, the carrier concentration is increased and the resistance of the component is reduced. By means of selection of a proper La/Fe element ratio, size of crystal grains is reduced and oxygen adsorption capacity is improved, so that the gas sensor is improved in sensitivity on ethanol, is reduced in working temperature and is reduced in response recovery time. A LaFe0.8O3 beside-heating-type ethanol gas sensor prepared in the invention can reach 138 in the sensitivity on ethanol in 1000 ppm at the working temperature of 140 DEG C, wherein the response and recovery times are respectively 1 s and 1.5 s. The gas sensor is less than 22 in all sensitivities on methane, acetone, carbon dioxide and glycerol in 1000 ppm. The gas sensor is high in sensitivity, is low in the working temperature, is ultrafast in response recovery property and is high in selectivity at the same time on ethanol, and is low in cost and is environmental-friendly.

The present invention discloses a copper oxide doped tin dioxide base ammonia gas sensitive sensor manufacturing method. The method comprises the following steps: sequentially placing a Cu target material with a purity of 99.99% and a Sn target material with a purity of 99.99% on two radio frequency sputtering targets, and placing a Al2O3 ceramic tube on a sample holder; carrying out vacuum pumping on the system before sputtering until air pressure of the system achieves 10<-3>-10<-5> Pa; opening gas path valves of oxygen gas and argon gas, wherein the air pressure is maintained to 6*10<0>-3*10<-1> Pa; carrying out pre-sputtering for 10 min, then removing a blocking disc, concurrently adjusting a power of the Sn target to 60-80 W, adjusting a power of the Cu target to 20-60 W, and sputtering for 45 min; opening the vacuum chamber to take the sample when the air pressure is 10<5> Pa; and carrying out annealing for 1-3 h at a temperature of 300-500 DEG C in a muffle furnace to obtain the finished product. The manufactured gas sensitive element provides good selectivity for ammonia gas, can quickly and effectively detect ammonia gas from a lot of mixing gas, and has characteristics of high sensitivity and short response recovery time.

The invention discloses a palladium-doped stannic oxide wrapped carbon nano tube which is prepared by using a gel-sol method. The carbon nano tube is structurally prepared by wrapping the surface of the carbon nano tube with palladium-doped stannic oxide crystal (Pd/SnO2), and the method comprises the following steps: dispersing the carbon nano tube into super-pure water in an ultrasonic mode, adding a stannic chlori precursor, dispersing in the ultrasonic mode again, subsequently adding a sodium tetrachloropalladate solution, uniformly stirring, mixing, adjusting the pH value to be 7-9, preserving for 0.2-36 hours at 30-200 DEG C so as to obtain milk white gel, washing and drying the gel, subsequently calcining at 200-700 DEG C so as to prepare the palladium-doped stannic oxide wrapped carbon nano tube. Due to adoption of noble metal and doping of the carbon nano tube, the gas-sensitive property of a stannic oxide-based gas sensor is greatly improved, the response and recovery time is shortened, and the low operation temperature is optimal.

The invention discloses a gold-doped titanium dioxide flower-like nanostructured material and a preparation method and an application thereof. In the nanostructured material, the average size of gold nanometer particle as a nucleus (pistil) is 20-50nm, and the average size of titanium dioxide nanoparticle as a casing (petal) is 50-100 nm. The preparation method comprises the steps of (1) mixing an auric chloride acid solution and a trisodium citrate solution, stirring, then adding a ascorbic acid solution and stirring, then adding a titanium tetrafluoride solution and stirring uniformly to obtain a mixed solution; (2) conducting high temperature hydrothermal reaction to the mixed solution obtained from step (1) for a period of time, and washing and drying a sediment obtained from the reaction to obtain a gold-doped titanium dioxide flower-like nanostructured material. The obtained material has the advantages that the size of the nanometer particles are uniform, and the disperse performance is good. The material is applied for preparing gas-sensitive elements, and has a high sensitivity and selectivity and short response recovery time to carbon monoxide.

The invention discloses a preparation method of a tin dioxide doped titanium dioxide based thin film acetone gas sensor. The preparation method comprises the following steps of: firstly, preparing an SnCl4.5H2O solution with the concentration of 14.9%; dropping hydrochloric acid and ammonia water until the pH (Potential of Hydrogen) value of the solution is about 6 before the dropping of the ammonia water stops; agitating for 30min, ageing the mixture for 2 days at room temperature, and drying the aged mixture; preparing a butyl titanate solution with the concentration of 23.1% from absolute ethyl alcohol; mixing de-ionized water and acetic acid according to the volume ratio of 1:1; weighing prepared SnO2 powder and dissolving the powder into the mixed solution; adding SnO2 and TiO2 in a mol ratio of 1:(25-50); standing for three hours; drying the obtained mixture at 100 DEG C for 2 hours, and crushing the dried mixture in an agate mortar to obtain nano TiO2 powder doped with SnO2; mixing the powder and methylcellulose in a ratio of 1:1; coating the mixture on a ceramic pipe; annealing the pipe at 500 DEG C to obtain the sensor. A sensor is high in sensitivity to acetone, short in response recovering time and low in working temperature.

The invention discloses a manufacturing method for a high sensitivity semiconductor nano ultraviolet light detector. According to the method, firstly, a two-dimensional ultrathin structure monocrystalline ZnO nano material is manufactured; the two-dimensional ultrathin structure monocrystalline ZnO nano material is transfered from a growth substrate; the two-dimensional ultrathin structure monocrystalline ZnO nano material is mixed with organic solution or deionized water; ultrasonic dispersion of the two-dimensional ultrathin structure monocrystalline ZnO nano material solution is carried out; the two-dimensional ultrathin structure monocrystalline ZnO nano material solution is coated on a surface of a semiconductor, insulation and conductive substrate; along a length direction of the two-dimensional ultrathin structure monocrystalline ZnO nano material, and conductive metal electrodes are plated at two ends; a mask is utilized to cover the two-dimensional ultrathin structure monocrystalline ZnO nano material, an insulation oxide covering layer is plated, an insulation oxide half-covering or symmetric covering structure is formed, and the two-dimensional ultrathin structure monocrystalline ZnO nano ultraviolet light detector is acquired. The method has advantages of simple structure, small volume, rapid response and high sensitivity.

The invention relates to a humidity sensor based on a TiO2 composite material, the humidity sensor comprises a ceramic substrate, a TiO2 composite layer coating the surface of the ceramic substrate, and a metal counter electrode prepared on the surface of the TiO2 composite layer, the TiO2 composite material is a TiO2 / graphene / metal nanowire / Fe3O4 composite material, TiO2 is TiO2 nanoparticles, Fe3O4 is Fe3O4 nanoparticles, and graphene is a carrier of the TiO2 nanoparticles and the Fe3O4 nanoparticles.

The invention relates to the technical field of gas sensors, and provides a nickel oxide/titanium dioxide nanorod composite structure gas sensor as well as a preparation method and application thereof. The gas sensor provided by the invention comprises a substrate, a nickel oxide/titanium dioxide nanorod composite structure layer and an interdigital electrode which are sequentially contacted frombottom to top. Nickel oxide and titanium dioxide in the nickel oxide/titanium dioxide nanorod composite structure layer are compounded to form a heterojunction, so that the gas sensitivity of the sensor is improved, and the gas sensitivity of the sensor can also be improved due to the unique oxidation-reduction characteristic of the nickel oxide. The gas sensor provided by the invention is enlarged in gas concentration detection range, short in response recovery time and high in sensitivity and repeatability, has good response to gases such as hydrogen, carbon monoxide and ammonia gas, and canrealize high-sensitivity detection just at room temperature. The preparation method provided by the invention has the advantages of simple steps, low cost, strong operability and low requirements onequipment, and can be used for large-scale synthesis.

The invention provides an all-inorganic perovskite micron sheet and a preparation method thereof, and a Schottky ultraviolet photoelectric detector and a preparation method thereof. The preparation method of the all-inorganic perovskite micron sheet comprises the steps of: the step 1, preparing a CsPbCl3 solution; the step 2, dripping the CsPbCl3 solution on a substrate, and then covering the other substrate on the substrate dripped with the CsPbCl3 solution to obtain a double-layer substrate with the CsPbCl3 solution; the step 3, moving the double-layer substrate into a container containing an anti-solvent, making the substrate higher than the liquid level, and then sealing the container; and the step 4, placing the container on a hot table for growing for 12-96 hours at 30-70 DEG C, andfinally growing a CsPbCl3 perovskite micron sheet on the substrate. A detector with an ITO left electrode/a perovskite micron sheet/an ITO right electrode structure is further prepared on this basis,has the advantages of high responsiveness, high sensitivity, quick response recovery time and the like, and has selective detection capability on ultraviolet light.

The invention relates to the technical field of gas sensitive sensor elements, in particular to a gas sensitive material, a preparation method and application thereof and a gas sensitive sensor element. The invention provides the gas sensitive material. The gas sensitive material comprises Fe2O3 with a hollow cubic structure and an AuPt alloy dispersed on the surface of the Fe2O3, and the AuPt alloy is nanoparticles. The gas sensitive material has relatively high detection sensitivity, relatively short response time and relatively good selectivity on trimethylamine.

The invention discloses a micron tin dioxide gas sensing material and a preparation method and application thereof, wherein the preparation method includes the following steps: configuring the tin dioxide and ethanol into a solution; then transferring the solution to a reaction kettle, after a certain period of reaction, obtaining a mixed solution containing the solid tin dioxide after the reaction system is cooled; and obtaining light yellow pure phase tin dioxide micron particles by centrifugation and drying. The micron tin dioxide gas sensing material and the preparation method and application thereof provide a new solution and technological process for the green, environmentally friendly and industrialized production of the micron SnO2, and the process of the method is simple and easyto conduct and is sound in repeatability. And the whole reaction system does not have any pollution to the environment, which is a green and environmentally friendly micron powder synthesis process. The gas sensor has strong practicability, good application prospect and economic benefits.

The invention discloses a photosensitization type porous tin oxide composite material and a synthetic method thereof, and an environmental sensor, belonging to the technical field of chemical engineering and sensors. The synthetic method of the porous tin oxide composite material comprises the following steps: preparing a first precipitate from P123, tin tetrachloride and an ammonium acetate solution; soaking the first precipitate with an acid solution, and then sequentially carrying out cleaning, drying and calcining treatment to obtain tin dioxide powder; preparing a second precipitate frombutyl titanate, cyclohexane, hydrochloric acid and ethanol; drying the second precipitate to obtain titanium dioxide powder; and mixing the tin dioxide powder and the titanium dioxide powder to obtainthe porous tin oxide composite material. When the porous tin oxide composite material is used for preparing a nitrogen dioxide gas sensor, the sensitivity of the gas sensor can be greatly improved, and the response recovery time of the gas sensor is shortened.

The invention discloses a carbon dioxide sensor for monitoring microbial growth and a preparation method thereof, and belongs to the technical field of carbon dioxide sensors and preparation methods thereof. The technical problem to be solved is to provide an improvement of a carbon dioxide sensor hardware structure for monitoring microbial growth. According to the technical scheme, an n-type gallium nitride layer is grown on a sapphire substrate in an epitaxial mode, a Ti/Al/Pt/Au electrode is deposited on a gallium nitride epitaxial wafer through a series of electrode preparation processes, and then a BP-PEI layer is prepared through liquid phase stripping of black phosphorus and functional modification of the black phosphorus, so that the miniaturized carbon dioxide gas sensor which is high in sensitivity and can be operated in real time is obtained. The carbon dioxide sensor is stable in performance, good in carbon dioxide gas-sensitive performance, low in price, small in size and simple in detection mode, and has the advantages of being disposable, free of pollution and the like. The carbon dioxide sensor is applied to monitoring of microbial growth.

The invention discloses a Gold-methyl amino stannous iodide-tin dioxide composite material, an application and a preparation method thereof. The Au/CH3NH3SnI3/SnO2 composite material can be used as room temperature NO2 semiconductor sensor material, and Au is introduced into CH3NH3SnI3 by a wet chemical method and partially decomposed into SnO2 by roasting thereby obtaining the Au/CH3NH3SnI3/SnO2composite material. The heterojunction is formed between CH3NH3SnI3 and SnO2, so that photo-generated electrons of CH3NH3SnI3 are easily transferred to a conduction band of SnO2, the photoactivation of SnO2 is accelerated, and the recombination of photo-generated electrons and holes is avoided, and the quantum efficiency of CH3NH3SnI3 is improved. A light-assisted gas sensitive material with highstability and large light absorption range is obtained under the interaction of three materials. The preparation method is simple and easy to be implemented.

The invention relates to a preparation method of a gas-sensitive element used for detecting a novel refrigerant, HC-600a, belonging to the technical field of the preparation process of a metal oxide semiconductor gas-sensitive element. The material of the gas-sensitive element of the invention is based on SnO2-Fe2O3 dibasic nano composite material, wherein, the mole ratio of Sn/Fe is 1 to 15: 100; noble metal elements, Au and Ru, with the mass percentage of 0.1 percent to 1.0 percent are doped by a dipping method, the doped gas-sensitive material is obtained, then is ground, and stirred to be pasty by a proper amount of deionized water and polyethylene glycol; and the pasty gas-sensitive material is uniformly coated on the surface of an aluminium oxide ceramic tube and is processed for two hours by annealing at the temperature of 500 DEG C so as to obtain the gas-sensitive element used for detecting the novel refrigerant HC-600a. The gas-sensitive element prepared by the invention has the advantages of high gas sensitivity to the refrigerant, HC-600a, good selectivity to interference gas, short time for response and recovery, good stability and the like, and can be used in the fields of leak detection of the novel and environment-friendly refrigerant, HC-600a, and detection of relevant industries of isobutene.

The invention relates to the field of constructional engineering, and discloses a sensor for detecting hydrogen sulfide gas at room temperature. The sensor comprises a reduced graphene oxide nanosheet 1, a copper-doped zinc oxide nanorod 2, an Au (50nm)/Ti (5nm) coating 3 and a glass substrate 4. When the surface of the sensor is exposed to H2S gas, H2S molecules are adsorbed on the surface of the nano composite sensor, and free electrons are released through interaction between pre-adsorbed oxygen and H2S. The free electrons neutralize holes in reduced graphene oxide (RGO) to reduce the size of a charge conduction channel, so that the width of a space charge region is increased, and the resistance of the sensor is increased. Therefore, the concentration of H2S gas is reflected. The hydrogen sulfide gas sensor has the advantages of high sensitivity, high hydrogen selectivity, stable performance and short response time.

The invention discloses a preparation method of a sensitive thin-film with a sandwich structure. The preparation method comprises the steps that first a CoTiO3 precursor solution and an ethanol suspension of graphene oxide are prepared, then a CoTiO3 precursor thin-film is plated on the surface of a Si substrate by using a dipping-pulling method, then a GO film layer is plated on the CoTiO3 precursor thin-film, then a CoTiO3 film layer is plated on the CoTiO3 precursor/GO thin-film, and finally calcination is performed to obtain the CoTiO3/rGO/CoTiO3 sensitive thin-film with the sandwich structure. The obtained thin-film exhibits higher sensitivity and selectivity to ethanol gas at operating conditions below 100 DEG C.