548results about How to "Reduce recombination rate" patented technology

A method of electrically contacting a semiconductor layer (13) coated with at least one dielectic layer (12) which is coated with a metal layer the metal layer (11) is applied on the dielectric layer (12) and the metal layer (11) is temporarily locally heated in a line, linear or dotted pattern by means of a source of radiation (9) in a controlled manner in such a way that a local molten mixture, is formed consisting exclusively of the metal layer (11), the dielectric layer (12) and the semiconductor layer (13) are located directly underneath the metal layer (11) and upon solidification, leads to an electrical contact between the semiconductor layer (13) and the metal layer (11).

A layered photocatalytic / thermocatalytic coating oxidizes contaminants that adsorb onto the coating into water, carbon dioxide, and other substances. The layered coating includes a photocatalytic outer layer of titanium dioxide that oxides volatile organic compounds. The coating further includes an intermediate layer of Group VIII noble metal doped titanium dioxide that oxidizes low polarity organic molecules. An inner layer of gold on titanium dioxide oxidizes carbon monoxide to carbon dioxide. When photons of the ultraviolet light are absorbed by the coating, reactive hydroxyl radicals are formed. When a contaminant is adsorbed onto the coating, the hydroxyl radical oxidizes the contaminant to produce water, carbon dioxide, and other substances.

The invention discloses an oxygen-doped carbon nitride / zinc oxide photo-catalyst as well as a preparation method and application of the oxygen-doped carbon nitride / zinc oxide photo-catalyst. The preparation method comprises the following steps: taking dicyandiamide or melamine as a precursor, calcining to prepare a carbon nitride nanosheet; adding a zinc oxide precursor into absolute ethyl alcohol, then adding dethylenetriamine, carrying out ultrasonic dispersion and subsequently enabling dispersion liquid to be subjected to hydrothermal reaction, so as to obtain zinc oxide nano material; enabling the zinc oxide nano material and the carbon nitride nanosheet to be subjected to ultrasonic dispersion in deionized water, subsequently adding hydrogen peroxide, then carrying out hydrothermal reaction again, and thus obtaining the oxygen-doped carbon nitride / zinc oxide photo-catalyst after the reaction is ended. The oxygen-doped carbon nitride / zinc oxide photo-catalyst adopts low-cost and easily available raw materials; the preparation condition can be easily achieved; the raw materials do not need to be calcined under the condition of high temperature, so that the cost for preparing the oxygen-doped carbon nitride / zinc oxide photo-catalyst is reduced, and the popularization and application of the preparation method are facilitated; meanwhile, the photo-catalyst is low in photo-production electron-cavity compounding efficiency and high in photo-catalytic activity.

A light emitting device having a plurality of light extracting elements defined on an upper surface of a semiconductor layer of the device, wherein the light extracting elements are adapted to couple light out of the device and to modify the far field emission profile of the device. Each element comprises an elongate region having a length at least twice its width and also greater than the effective dominant wavelength of light generated in the device. The elongate region extends orthogonal to the upper surface but not into the light emitting region of the device and may be oriented at an angle of less than 45° relative to one of a pair of basis axis defining a plane parallel to the semiconductor layer. Each elongate region is spatially separated from neighbouring elongate regions such that it perturbs light generated in the light emitting region independently of the neighbouring regions.

The invention discloses a metal-graphene-titanium dioxide nanotube array photocatalyst and a preparation and application method thereof. Graphene and metal are taken as common carriers of photo-induced electrons of titanium dioxide, thus the recombination rate of the photo-induced electrons and holes is lowered, and finally, the degradation efficiency of the catalyst to organic pollutants is improved through the adsorption performance of the graphene to the organic pollutants. The catalyst has good performance in the aspect of treating water pollutants, and has the advantages of simple preparation method and low cost.

A system for disinfecting a fluid containing microorganisms or chemical contaminants includes a plurality of photocatalyst surfaces secured to a solid surface upon which a fluid to be disinfected contacts. A structure for removing a portion of the photogenerated electrons is in electrical contact with the photocatalyst layer, wherein an electron-hole recombination rate involving the photogenerated electrons and holes is reduced, thus increasing the removal rate of microorganisms or chemical contaminants from the fluid. The system can include a source of photons having a wavelength corresponding to a band gap energy of the photocatalyst to illuminate the photocatalyst layer. The invention can be used in air supply registers of a heating, ventilating and air conditioning system, or in air ducts, or used to disinfect wall coverings, floor coverings, envelopes, packages, and clothing articles.

A solar cell includes a semiconductor substrate, an emitter layer, at least one emitter contact region and at least one first electrode. The emitter layer is formed on at least one surface of the semiconductor substrate. A p-n junction is formed between the emitter layer and the semiconductor substrate. The emitter contact region is formed on portions of the emitter layer and has the same type of dopant as the emitter layer. The emitter contact region has a higher dopant concentration than the emitter layer. The first electrode is coupled with the emitter contact region.

In a photoelectric conversion device, in a contact between a p-type semiconductor 3a and an electrode 2, an n-type semiconductor 6 of a conductivity type opposite to that of the p-type semiconductor is provided between the p-type semiconductor 3a and the electrode 2. The existence of the n-type semiconductor 6 allows a recombination rate of photo-generated carriers excited by incident light to be effectively reduced, and allows a dark current component to be effectively prevented from being produced. Therefore, it is possible to improve photoelectric conversion efficiency as well as to stabilize characteristics. Further, a tunnel junction is realized by increasing the concentration of a doping element in at least one or preferably both of the p-type semiconductor 3a and the n-type semiconductor 6 in a region where they are in contact with each other, thereby keeping ohmic characteristics between the semiconductor and the electrode good.

The invention discloses a preparation method of a photocatalytic ultrafilter membrane material with visible light activity. The method comprises the following steps: 1, preparing N-TiO2 powder; 2, preparing N-TiO2 / GO particles; 3, preparing an ultrafilter membrane; and 4, producing an ultrafilter membrane with the surface loaded with N-TiO2 / GO: processing the N-TiO2 / GO particles to prepare an N-TiO2 / GO dispersion, tiling the ultrafilter membrane on a suction filtration device, pouring the N-TiO2 / GO dispersion, carrying out vacuum pumping, and airing the obtained membrane to obtain the ultrafilter membrane with the surface loaded with N-TiO2 / GO. The photocatalytic material with the advantages of visible light activity, hydrophilic property and difficulty in loss of nano-particles is obtained through the preparation method of the photocatalytic ultrafilter membrane material with visible light activity.

The invention relates to a nanometer ZnO / graphene photo-catalyst and a preparation method thereof. The photo-catalyst is a composite nanometer photo-catalyst which adopts the graphene as the frame and is carried with ZnO, wherein the mass rate of the graphene and the ZnO nanometer particles is 1:100-10:100. Because of adding of GS, the recombination rate of the electron-hole is reduced, and the photo-degradation ratio is greatly improved during the process of degrading methyl oranges under the irradiation of ultraviolet lights. If optimization of parameters is considered, If optimization of parameters, such as optimum ratio of the adding quantities of ZnO and GS, and the influences of pH and temperature are considered, so the prepared ZnO / GS combined catalyst has low cost, can be recycled and used, has good photo-catalyst effect, and can be applied to the photo-catalyst treatment of industrial waste water and waste gas.

A heterojunction composite material consisting of one-dimensional In2O3 hollow nanotube and two-dimensional ZnFe2O4 nanosheets and its application are disclosed. When using this material for catalytic reactions, the hollow cavity and two-dimensional nanosheets of hollow nanomaterials can not only reduce the migration distance to accelerate the electron-hole separation, but also provide a large surface area and rich active sites to promote pollution adsorption and surface catalysis. At the same time, multiple light scattering or reflection in the hollow cavity of the hollow nanomaterials can increase light absorption and utilization. In addition, the heterojunction photocatalyst constructed by growing two-dimensional semiconductor nanosheets on a tubular substrate can promote the effective separation of photogenerated electrons and photogenerated holes, thereby improving the catalytic efficiency. In terms of catalytic performance, In2O3 @ ZnFe2O4 shows effective degradation of tetracycline, and due to its ferromagnetism, it shows convenient and good separation effect and has good recycling performance.

The invention relates to a visible light responsive photocatalysis material Ag@Ag3VO4 and a preparation method thereof. The Ag@Ag3VO4 photocatalysis material is of a near-spherical composite structure of depositing silver nano granules on the surfaces of silver vanadate granules, wherein the silver vanadate granules have the diameter of 6.5-7.5 mu m, and the surface deposited nano granules have the particle size of 5-25 nm. The invention also provides a preparation method of Ag@Ag3VO4. According to the invention, silver is deposited and loaded on the surface of Ag3VO4, thus the photocatalysis performance of Ag3VO4 is farther improved; and the method has the advantages of simple method, mild reaction conditions, convenience for operation, low energy consumption and the like.

The embodiment of the invention discloses a texturing method for a solar cell. The method comprises the following steps of: texturing the front surface of the solar cell; and polishing the back surface of the solar cell. By the provided texturing method, a low-reflectivity textured surface structure is formed on the front surface of the solar cell, and a high-reflectivity polished surface structure is formed on the back surface of the solar cell; and by the high-reflectivity polished surface structure, the long wave response is increased, and a recombination rate of a back metal electrode and a silicon wafer is reduced; and the open-circuit voltage, the short-circuit current and filling factors are improved, so the utilization efficiency of the solar cell can be improved. Furthermore, the texturing method is lower in cost, and is simple, so the texturing method can be widely applied to commercial production.

The invention provides an acidified mixed crystal TiO2 nanowire loaded photocatalyst. The photocatalyst is prepared by using the following method: dispersing titanium dioxide P25 in a NaOH aqueous solution, carrying out hydrothermal reaction on the obtained mixture, and after the reaction is completed, filtering out precipitates; putting the precipitates into a hydrochloric acid solution, carrying out impregnation acidification, washing the precipitates by using deionized water, drying the precipitates in a vacuum drying oven, and putting the precipitates into a muffle furnace and calcining for 2-8h at the temperature of 500-600 DEG C so as to obtain a mixed crystal TiO2 nanowire; adding the mixed crystal TiO2 nanowire and transition metal salt into an ethanol aqueous solution, dropwise adding a sulfuric acid aqueous solution, soaking and stirring, carrying out a hydrothermal reaction, and after the reaction is completed, removing liquid supernatant; and carrying out vacuum drying on the obtained object so as to obtain the photocatalyst. The photocatalyst can be applied to the visible light catalytic oxidation reaction of industrial organic wastewater, and is high in catalytic activity, good in stability, economical and efficient.

The invention discloses a graphene / chitosan / cuprous oxide composite material and a preparation method and applications thereof, which belong to the technical field of visible light catalytic materials. The composite material mainly comprises graphene, chitosan and cuprous oxide, wherein the graphene has extremely good electron capture and transmission performances, and as a carrier of photo-generated electrons, the graphene reduces the recombination rate of photo-generated electrons and holes of the cuprous oxide; by using the excellent adsorption property of the graphene to organic pollutants, the photocatalytic efficiency of a photocatalyst is improved; a good synergistic effect exists among the composited chitosan, the graphene and the cuprous oxide, and while the adsorption effect of the catalyst is improved, the degradation performance of the visible light catalyst to organic pollutants is improved. Under same conditions, compared with cuprous oxide, and cuprous oxide / chitosan, the graphene / chitosan / cuprous oxide composite material shows higher adsorption capacity and photocatalytic properties.

The invention discloses a modified graphite phase carbon nitride photocatalyst as well as a preparation method and application thereof. The modified graphite phase carbon nitride photocatalyst is prepared from urea and salicylic acid serving as raw materials by virtue of calcination, wherein a mass ratio of urea to salicylic acid is 1:(0.002-0.02). The modified graphite phase carbon nitride photocatalyst disclosed by the invention has the advantages of being high in specific surface area, wide in light absorption range, low in electron-hole pair recombination rate, excellent in photocatalyticperformance and the like, and has multiple reactive sites, excellent application value and application prospects. The preparation method has the advantages of being simple in process, wide in raw material source, low in cost, high in preparation efficiency, high in yield and the like, is suitable for large-scale preparation and is favorable for industrial production. The modified graphite phase carbon nitride photocatalyst disclosed by the invention can be used for degrading organic pollutants, has the advantages of being simple in process, convenient to operate, low in cost, high in treatmentefficiency, excellent in degradation effect and the like, and has excellent effects of degrading the various organic pollutants.

The invention relates to a preparation method and application of a novel photocatalysis material. On the basis of the action principle of semiconductor heterojunction, bismuth oxyhalide and titanium dioxide are composited to obtain a novel titanium based photocatalysis material with the characteristics of high catalytic activity, wide applicability and good stability. The preparation method adopted by the invention is simple and efficient and is easy to implement, and the use amount of the bismuth oxyhalide is less and is about 1-3%, therefore no increase of overmuch cost may be caused. The photocatalysis material obtained by the reaction is a porous nano particle with larger specific surface area, good dispersibility and high degree of crystallinity. In addition, the photocatalytic activity of the bismuth oxyhalide / titanium dioxide composite photocatalyst is very excellent, and either under ultraviolet or visible light irradiation, the bismuth oxyhalide / titanium dioxide composite photocatalyst can show high degradation performance both on gas phase and liquid phase organic matters.

The invention discloses a preparation method of a graphite type carbon nitride photocatalytic material, belonging to the field of the material preparation and photocatalytic technology. The graphite type carbon nitride photocatalytic material takes dicyandiamide and barbituric acid as co-precursors, adopts lithium chloride and potassium chloride as heating mediums, and is prepared in protective atmosphere through directly burning. The prepared g-C3N4 has excellent visible light absorption ability and the laminated structure characteristics, and has the degradation efficiency up to 83.8% to rhodamine B within 90min under visible light. The preparation method is simple, the raw materials are easily available, the visible light catalytic efficiency is high, and the graphite type carbon nitride photocatalytic material has wide application prospect in the photocatalytic field.

The invention relates to a preparation method of a bismuth oxyhalide / bismuth oxide visible-light photocatalyst and belongs to the field of visible-light photocatalyst preparation. The method comprises the following steps: dissolving bismuth nitrate in a salpeter solution, adjusting pH with alkali lye, stirring, filtering, washing, drying, calcining at high temperature of 300-600 DEG C for 3-10 hours to prepare yellow bismuth oxide; adding a proper amount of hydrochloric acid, hydrobromic acid or hydroiodic acid with a certain concentration into the prepared bismuth oxide, carrying out an ultrasonic reaction, carrying out centrifugal separation, and drying at constant temperature of 50-100 DEG C for 4-10 hours to obtain the bismuth oxyhalide / bismuth oxide photocatalyst. The method can be carried out at room temperature and at normal pressure. Equipment is simple and easy to operate, can be put into practical use and has a potential application in industrial production. According to the prepared bismuth oxyhalide / bismuth oxide visible-light photocatalyst, the problem of high photo-generated electron and carrier recombination rate is solved effectively, and photocatalytic performance is greatly enhanced.

The invention relates to a passivation contact N-type solar cell and a manufacturing method, a component and a system. The passivation contact N-type solar cell comprises an N-type crystalline siliconsubstrate. A front surface successively comprises a p+ doped area, a front surface passivation anti-reflection film, a front surface main grid and an auxiliary grid from inside to outside. A back surface successively comprises a tunneling oxide layer, an n+ doped polysilicon layer, a back surface passivation film and a back surface electrode from inside to outside. The back surface electrode andthe n+ doped polysilicon layer form ohmic contact. A front surface auxiliary grid is aluminum which forms ohmic contact with the p+ doped area. The cell has advantages that the front surface auxiliarygrid is aluminum, the aluminum can directly burn through SiNx and a recombination rate with silicon is low, grooving is not needed, a silver paste is saved and an open-circuit voltage is high; the n+doped polysilicon layer is taken as a back surface field of the N-type solar cell, and an excellent field passivation effect is provided for a silicon substrate surface; and a recombination rate of minority carriers is low, and a cell open-circuit voltage, a short circuit current and energy conversion efficiency are high.

The invention discloses a bismuth ferrite-graphene nanometer composite material and a preparation method thereof. The composite material is composed of graphene and BiFeO3 nanoparticles coated on the surface of graphene. The BiFeO3 nanoparticles have a diameter of 100-500nm, and the graphene has a diameter of 5-10 mum and thickness of 2-15nm. The preparation method is as follows: first, preparing BiFeO3 precursor nanoparticles by a co-precipitation method; and then mixing the nanoparticles with the graphene for a hydrothermal reaction, so as to prepare the bismuth ferrite-graphene composite material. The bismuth ferrite-graphite composite material provided by the invention has band gap of 1.78-2.15eV, strong visible light absorption, and large specific surface area, and can effectively improve separation of photo-generated carriers, reduce recombination rate of the carriers, and show photocatalytic performance more excellent than that of nanoparticles. Experiments show that the nanometer composite material can degrade more than 80% of target degradation product in 2 h, so as to demonstrate excellent visible photocatalytic activity.

The invention relates to a monodispersed spherical titanium dioxide core-shell structure composite material and a preparation method thereof. The monodispersed spherical titanium dioxide core-shell structure composite material comprises an inner core formed by monodispersed carbon spheres and a titanium dioxide shell layer covering the inner core, wherein noble metal is doped in the titanium dioxide shell layer.

The invention relates to a three dimensional ordered meso-porous Au-TiO2 / IO-SiO2 film visible light photocatalyst and a preparation method thereof, and belongs to the field of titanium dioxide photocatalysis. The method comprises the following steps: preparing polystyrene microspheres with different particle sizes through a soap-free emulsion polymerization technology, and synthesizing a high quality silica inverse opal film template with different apertures through a polystyrene microsphere and silica precursor liquid co-assembling technology with the polystyrene microspheres as a template; and depositing Au nanoparticles in a titanium dioxide precursor liquid through a chemical reduction technology by using NaBH4 as a reducing agent, and injecting the Au nanoparticles to the silica inverse opal template in order to finally make a precious metal deposited three dimensional ordered meso-porous Au-TiO2 / IO-SiO2 film. The special structure of photonic crystals can enhance the light absorption; and the Fermi level of deposited Au is lower than that of titanium dioxide, so electron-cavity separation is facilitated, thereby increase of the photocatalysis efficiency is facilitated.

The invention discloses a synthesis method of a graphite phase carbonitride homotype heterojunction photocatalysis material with a multilayer structure. The method comprises the following steps of preparing a melamine / cyanuric acid suspension and urea water solution; performing preparation by using the melamine / cyanuric acid suspension to obtain melamine / cyanuric acid suspension macromolecular crystals completing the assembly reaction; adding the melamine / cyanuric acid suspension macromolecular crystals into the urea water solution; performing calcination on the urea-(melamine / cyanuric acid) composite precursor obtained through preparation to obtain the graphite phase carbon nitride (g-C3N4) homotype heterojunction photocatalysis material with multilayer structures with g-C3N4 nanometer particles deposited on the g-C3N4 micrometer tubes. The synthesis method provided by the invention has the advantages that the conditions are mild; the preparation process is simple and convenient; the controllability is high; the obtained photocatalysis material can be applied to methyl orange degradation in visible light; the effect is obvious.

The invention discloses a hydrothermal preparation method of flaky nano copper oxide / graphene composite materials. Copper acetate monohydrate with different mass is dissolved in deionized water, graphene oxide solutions are added to the solutions, the solutions are stirred magnetically, then sodium hydroxide is dissolved in deionized water, the mixtures are dropwise added to copper acetate monohydrate and graphene oxide mixed solutions stirred previously, the mixtures are stirred magnetically for 1 h and then subjected to hydrothermal treatment for 10 h, after the reaction ends and products are cooled to the normal temperature, the products are washed repeatedly with deionized water and then placed in a vacuum drying oven to be dried at the temperature of 60 DEG C, and flaky nano copper oxide / graphene composite material powder containing copper oxide and graphene in different mass ratios is obtained after drying. Flaky nano copper oxide / graphene composite material samples prepared with the hydrothermal method have the characteristics of good crystallinity, high uniformity, flaky microstructures and the like, and the composite materials can increase reaction rates of light-catalyzed reactions.

The invention discloses a method used for photocatalytic reduction of carbon dioxide. The method mainly comprises preparation of a Y-doped TiO2 photocatalyst and photocatalytic reduction of carbon dioxide. According to the method, the Y-doped TiO2 photocatalyst is prepared via sol-gel method and roasting at 300 to 800 DEG C, and doping amount ranges from 0.1 to 8%. In carbon dioxide photocatalytic reduction processes, in an inner illumination photo-catalytic reactor, 200ml of Na2CO3 or Na2SO3 aqueous solution is added as a reaction solution, the Y-doped TiO2 photocatalyst is added, a 500W mercury lamp or xenon lamp is taken as a light source, carbon dioxide is added, and carbon dioxide photocatalytic reduction is carried out for 1 to 6h at normal temperature so as to obtain carbon dioxide reduction product formic acid. The method is simple; operation is convenient; the process is green; and greenhouse gas carbon dioxide is transformed into an useful chemical product.

The invention discloses a preparation method of an oxygen-doped porous g-C3N4 photocatalyst. The method comprises dissolving melamine in deionized water, adding an organic substance containing an aldehyde group dropwise under heating and stirring conditions, putting the obtained solution into an oven, drying the solution at 80-150 DEG C to obtain a precursor, grinding the precursor, calcining theprecursor in an inert gas atmosphere to obtain an intermediate product, and calcining the intermediate product in an air atmosphere to obtain a target product. The porous oxygen-doped g-C3N4 nanometermaterial prepared by the method of the invention can effectively promote electron transfer, reduce the recombination rate and increase photocatalytic activity, and precursor treatment in this mannercan not only change the structure but also introduce useful foreign atoms. Moreover, the method is cheaper than conventional oxygen doping methods and is simple and convenient to operate. The photocatalyst can effectively degrade organic pollutants under visible light irradiation.

A solar cell includes a substrate of a first conductive type, a plurality of first electrodes which are positioned on one surface of the substrate and extending in a first direction, an emitter region which is electrically connected to the first electrodes and is of a second conductive type opposite the first conductive type, a plurality of second electrodes which are positioned on another surface of the substrate and extending in the first direction, and a back surface field region including a plurality of first field regions which are locally formed at locations corresponding to the second electrodes in the same direction as the second electrodes and are electrically connected to the second electrodes. A distance between adjacent first field regions is less than a distance between adjacent second electrodes.

The invention discloses a graphene quantum dots-bismuth tungstate composite photocatalyst and a preparation method thereof. According to the composite photocatalyst, bismuth tungstate is used as a photocatalyst, and graphene quantum dots are loaded on bismuth tungstate. The preparation method comprises the following steps: carrying out ultrasonic mixing on a graphene quantum dots solution, sodiumtungstate and deionized water, and then adding cetyl trimethyl ammonium bromide to obtain a solution A; dissolving bismuth nitrate in acetic acid to prepare a solution B, slowly adding the solution Binto the solution A and stirring to obtain a precursor suspension; transferring the precursor suspension into a microwave reaction instrument to carry out a microwave reaction, centrifuging the suspension and drying to prepare a graphene quantum dots-modified bismuth tungstate composite photocatalyst. The composite photocatalyst has good degree of crystallization, uniform morphology, has high photocatalytic activity, strong light absorption capability and high light-generated electron-cavity separation efficiency, and is safe and stable. The technology is simple, reaction conditions are mild and easy to control. The graphene quantum dots-bismuth tungstate composite photocatalyst is easy for industrial production and has good industrial application prospect.