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

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.

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.

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 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 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 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 relates to a preparation method of a Bi/Bi4O5X2(X is equal to Br, I) complex photocatalyst of organic boron in oxidation fracturing fluid under a visible light. The preparation method comprises the steps of dissolving a compound containing 7.8mmol and 10.4mmol of bismuth elements into glycerol, and then dissolving 4mmol of compound containing iodine and bromine elements into the glycerol respectively; adding the solution containing the iodine and bromine elements into the solution containing the bismuth elements respectively, and carrying out stirring reaction for 60min; transferring the mixed solution into a reaction kettle, reacting at 160 DEG C for 16h, and cleaning and drying to obtain a precursor; weighing 0.3g of precursor, adding 50ml of distilled water, carrying out hydrolysis at the water bath temperature of 50 DEG C, and drying to obtain solid powder which is the Bi/Bi4O5X2(X is equal to Br, I) complex photocatalyst. The prepared catalyst has improved response to the visible light, especially has higher activity on removing the organic boron in the fracturing fluid, and can be applied to removing the organic boron in the fracturing fluid.

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.