140results about How to "Narrow band gap" patented technology

The invention belongs to the field of photocatalyst preparation and particularly relates to a preparation method of an amorphous iron oxyhydroxide/bismuth vanadate composite photocatalytic material. The preparation method of the amorphous iron oxyhydroxide/bismuth vanadate composite photocatalytic material comprises the following process steps of synthesizing bismuth vanadate through a hydrothermal method, adopting synthesized bismuth vanadate as a substrate, putting the bismuth vanadate into a mixed solution of ferric chloride and ammonium bicarbonate for stirring, and drying the mixture after centrifuging to obtain a finished product, namely the amorphous iron oxyhydroxide/bismuth vanadate composite photocatalytic material. According to the preparation method, an amorphous material is used as a cocatalyst, and due to the special structure of the amorphous material, the amorphous material lacks ordered atomic arrangement and thus has narrower forbidden bands. These characteristics lead to more defects on the surface of a catalyst, more active sites are provided, the light absorption range is enlarged, and the photocatalytic performance is further improved.

The invention relates to a preparation method for a GaAs/Ge/GaAs heterostructure SPiN diode string used for a sleeve antenna. The preparation method comprises the steps of (a), selecting a GeOI substrate; (b), etching a top layer Ge layer of the GeOI substrate to form a first trench and a second trench in the top layer Ge layer; (c), depositing a GaAs material in the first trench and the second trench; (d), performing P type ion implantation on the GaAs material in the first trench by adopting an ion implantation process to form a P type active region, and performing N type ion implantation on the GaAs material in the second trench to form an N type active region; and (e), forming lead holes in the surfaces of the P type active region and the N type active region and performing metal sputtering to form the GaAs/Ge/GaAs heterostructure SPiN diode. According to the embodiments, the high-performance Ge-based SPiN diode string, which is applicable to formation of a solid-state plasma antenna, can be prepared and provided through a deep trench isolation technology and the ion implantation process.

The present invention provides an ultra steep average subthreshold swing nano wire tunneling field effect transistor and a method for preparing the same which belong to the field effect transistor logic device field of the CMOS ultra large scale integration (ULSI). The tunneling field effect transistor adopts a nano wire structure of core-multilayered shell, and the material band gap of a multilayered shell part is increased continuously along the radius direction of the nano wire. According to the present invention, a subthreshold slope degradation phenomenon in a device transfer characteristic can be restrained effectively, at the same time, an average subthreshold slope of the tunneling field effect transistor is reduced remarkably, and a more steep minimum subthreshold slope is kept.

The invention relates to a method for preparing a graphene-SnIn4S8 nano composite photocatalyst at low temperature by adopting a coprecipitation method. The method is characterized by comprising the following steps: preparing graphene oxide by utilizing a modified Hummers method, and reducing the graphene oxide by utilizing 80% hydrazine hydrate to obtain reduced graphene oxide; dissolving raw materials such as tin chloride, indium chloride and thioacetamide in an organic alcohol solution, mixing the reduced graphene oxide which is prepared in advance, and preparing the graphene-SnIn4S8 nano composite photocatalyst bonded in chemical bonds by utilizing a low-temperature co-precipitation method. The method has characteristics that the reaction temperature is low, the reaction time is short, the prepared graphene-SnIn4S8 nano composite photocatalyst is relatively large in specific surface area and narrow in energy gap, photo-generated electrons can be effectively separated from electron holes, the stability is high, the regeneration performance is good, and the light absorption activity and the light catalytic activity are relatively strong under the visible light.

The invention provides a graphite-phase-like carbon nitride-(110) crystal face bismuth vanadate Z-type heterojunction photocatalyst and a preparation method and application thereof. The method comprises the following steps of 1, preparing exposed (010) crystal face BiVO4 powder and H2SO4 modified g-C3N4 powder; 2, adding the exposed (010) crystal face BiVO4 powder into water, and conducting ultraviolet illumination; dissolving the modified g-C3N4 powder into water, and conducting ultraviolet illumination; 3, adding a BiVO4 solution after ultraviolet treatment into a g-C3N4 solution which is subjected to ultraviolet illumination and negatively charged to obtain a precursor solution, and conducting ultraviolet illumination on the precursor solution to obtain g-C3N4-(110) crystal face BiVO4Z-type heterojunction photocatalyst powder. The catalyst enlarges the response range of visible light, reduces the recombination rate of electrons and hole pairs, improves the separation efficiency of charge carriers and improves the photocatalytic performance of the BiVO4-based composite photocatalyst.

The invention discloses a tunneling field effect transistor and a preparation method, and belongs to the field of a field effect transistor logic device of a CMOS (Complementary Metal Oxide Semiconductor) ultra-large scale integrated circuit (ULSI). A tunneling source region and a channel region of the tunneling field effect transistor are of heterogeneous structures in the vertical direction of the device; the upper layer is made of a semiconductor material with larger forbidden bandwidth; the middle layer is made of a semiconductor material with smaller forbidden bandwidth; the lower layer is a semiconductor substrate with the larger forbidden bandwidth. Compared with the prior art, the transistor and the method have the advantages that the degradation phenomenon of sub-threshold slope in device transfer characteristic can be effectively inhibited, meanwhile the average sub-threshold slope of the tunneling field effect transistor is obviously reduced, and steep minimum sub-threshold slope is kept.

The invention provides a femtosecond laser ablation-based infrared-enhanced Si-PIN detector and a preparation method thereof. The detector comprises an intrinsic silicon substrate, a femtosecond laser ablation microstructure layer, an infrared-enhanced amorphous silicon-ruthenium alloy film, a lower electrode, a P-type region, an annular P+ type region and an upper electrode, wherein the femtosecond laser ablation microstructure layer is a micron sharp cone array. The unabsorbed light which transmits through a space charge region is reflected for multiple times; a light propagation path and the photo capture ratio are increased; absorption and utilization of the light are improved; more photo-induced carriers are excited; the responsivity of the detector is improved; a relatively narrow optical band gap is obtained through controlling the ruthenium content; and the band gap of a silicon material is narrowed, so that near-infrared light with lower energy and a larger wavelength is captured; absorption of the near-infrared light can be additionally increased; and the detection spectrum range of a photoelectric detector is expanded.

The invention discloses a copper sulfide/bismuth vanadate heterojunction photocatalyst and a preparation method thereof. The copper sulfide/bismuth vanadate heterojunction photocatalyst comprises a copper sulfide and bismuth vanadate, and the copper sulfide is attached to the bismuth vanadate. The preparation method comprises the following steps: preparing a suspension of bismuth vanadate and copper nitrate; preparing a suspension liquid of bismuth vanadate, copper nitrate and sodium thiosulfate; carrying out water bath reaction on the suspension liquid of bismuth vanadate, copper nitrate andsodium thiosulfate to obtain the copper sulfide/bismuth vanadate heterojunction photocatalyst. The copper sulfide/bismuth vanadate heterojunction photocatalyst has the advantages of being wide in visible light response range, high in quantum efficiency, high in photocatalytic activity and the like, is a novel semiconductor photocatalytic material, and has good application value and application prospect, the catalyst prepared by the preparation method is high in crystallization degree, free of impurities in the preparation process, simple in process, mild in reaction conditions, convenient to operate, clean, pollution-free and the like, is suitable for large-scale preparation, and is convenient for industrial utilization.

The invention discloses a perovskite hybrid solar cell based on a cadmium sulfide nanoarray. The perovskite hybrid solar cell comprises a substrate, a transparent metal electrode layer, an inorganic electron transport layer, a photosensitive layer, a hole transport layer and a metal electrode layer; the transparent metal electrode layer, the inorganic electron transport layer, the photosensitive layer, the hole transport layer and the metal electrode layer are orderly arranged on the substrate from bottom to top; the inorganic electron transport layer is formed from the cadmium sulfide nanoarray; the form of the cadmium sulfide nanoarray is nanorod, nanowire or nanotube. The perovskite hybrid solar cell is characterized in that the cadmium sulfide nanoarray is taken as the electron transport layer material instead of high-temperature sintered metal oxides widely used at present, and has relatively small band gap width and is relatively wide in an absorption spectrum to sunlight; the interface area of the electron transport layer material and the material of the photosensitive layer is increased and a continuous electron transport channel is provided; compared with high temperature sintering, the perovskite hybrid solar cell has the advantages of low cost, low energy consumption and easily realizable large-area preparation.

The invention discloses a graphene and vanadate composite nano-fiber photocatalyst and a preparation method thereof. The composite nano-fiber photocatalyst is prepared by compounding two components including graphene and vanadate according to a proportion that 10-30mg of the graphene is used when 1mmol of the vanadate is used; and the graphene and vanadate composite nano-fiber photocatalyst is obtained by taking an organic vanadium salt with good alcohol solubility and rare-earth metal nitrate as precursor reactants, preparing a spinning solution by making use of a PVP (polyvinyl pyrrolidone) and ethanol system, uniformly dispersing graphene powder into the spinning solution at the same time, performing electric spinning to form silks by using an electrostatic spinning device, and performing high-temperature roasting. Graphene and vanadate composite fibers show rich porous layer structures and narrower band gap width, show very good visible light catalytic degradation capacity to a contaminant ofloxacin in water, and can be quickly separated from a solution through precipitating.

The invention discloses a preparation method for an Au-ZnIn2S4 nanoarray electrode photocatalytic nitrogen fixation material, belonging to the field of preparation and modification methods for photoelectrochemical catalytic materials. The preparation method comprises the following steps: based on a ZnIn2S4 nanoarray electrode, performing photodeposition of Au nanoparticles on the surface of the ZnIn2S4 nanoarray electrode so as to improve the photocatalytic nitrogen fixation performance of ZnIn2S4; growing a layer of a ZnIn2S4 nanosheet array on FTO conductive glass by adopting a hydrothermalmethod, and depositing Au particles on the surface of the ZnIn2S4 nanosheet array by adopting a photodeposition method so as to prepare an Au-ZnIn2S4 electrode; fixedly putting the Au-ZnIn2S4 electrode slice in an aqueous methanol solution, continuously introducing high-purity nitrogen, converting N2 into NH3 under the illumination of a xenon lamp, and then converting NH3 into NH4<+>; and mixing areaction solution with a Nessler's reagent for color development, and determining the concentration of NH4<+> in the reaction solution so as to further determine the photocatalytic nitrogen fixationperformance of the material. The method has the advantages of simple preparation, loose preparation conditions, no toxicity, and easy recovery and cyclic utilization of the material in the process ofapplication; since ZnIn2S4 is narrow in forbidden band width and can absorb visible light in a larger range, and Au also has strong absorption performance in a visible light range, the material is increased in the comprehensive utilization rate of visible light.

The invention discloses a silver oxide tungsten bronze composite heat-insulating material with high visible light photocatalytic performance and a preparation method thereof. The silver oxide-tungsten-bronze composite heat-insulating material is formed by silver oxide and tungsten bronze: the silver oxide-coated potassium-tungsten bronze; under the condition of visible light, rhodamine B solutionwith a concentration of 20mg/L was used, and the degradation rate of rhodamine B is over 95% within 30 minutes of visible light irradiation. In the preparation method, the tungsten bronze nano powderis dispersed in the deionized water, and the dispersion liquid A is obtained by ultrasonic dispersion; the silver nitrate is added into the dispersion A, the ultrasonic treatment is carried out underthe dark condition, and then the tungsten bronze and the silver nitrate solution are fully mixed under the dark condition to obtain the dispersion liquid B; alkaline solution is added into the dispersion liquid B, the pH value is controlled, reaction is continuously carried out after the completion of the dropping, then washing, centrifuging and drying are carried out orderly. The material has good transparency, near-infrared shielding performance and heat insulation performance while remarkably improving the utilization efficiency of visible light.

The invention relates to the field of environment functional materials and specifically relates to a visible-light response MoS2/GO/g-C3N4 ternary composite photocatalytic material and a preparation method thereof. The ternary composite photocatalytic material is prepared by compounding MoS2, GO and g-C3N4; and MoS2 is uniformly loaded on GO in a nanoparticle way and forms the ternary composite photocatalytic material with a compact structure under the pi-pi conjugate action of GO and g-C3N4. Shown by photocatalytic degradation performance tests, the MoS2/GO/g-C3N4 ternary composite photocatalytic material provided by the invention has better RhB photocatalytic degradation performance than an MoS2/g-C3N4 monomer and an MoS2/GO binary composite catalyst and has a good application prospect and economic benefit on the aspect such as solar energy conversion and sewage treatment.

The invention discloses a synthesis method of a graphene/ZnS-MoS2 nano solid solution photocatalyst having visible light catalytic activity. The method includes steps of: preparing graphene oxide (GO)through an improved Hummers method, then dispersing the GO in organic solvent and performing ultrasonic treatment to form a homogenous solution; with inorganic zinc salt, inorganic molybdenum salt and sulfur source as raw materials, successively dissolving the raw materials in an organic solution, and adding the graphene solution prepared before; performing a reaction at 180-220 DEG C so that thenano solid solution ZnS-MoS2 is uniformly adhered to the graphene thin film to form the rGO ZnS-MoS2 nano solid solution photocatalyst combined with chemical bonds. The photocatalyst, when the content of graphene is 5-14%, has excellent visible light catalytic performance. The photocatalyst has large specific surface area, narrow and continuously-adjustable energy gap, can effectively promote separation and migration of photo-induced electron-hole, and has excellent photo-absorption and photo-catalytic activity under visible light.

The invention discloses a bismuth vanadate/silver chromate heterojunction photocatalyst as well as a preparation method and application thereof. The heterojunction photocatalyst is formed by assembling BiVO4 and nano Ag2CrO4 selectively deposited on the crystal face of the BiVO4 (040), the BiVO4 is of a chamfered square bipyramid microstructure, and the mass of the BiVO4 accounts for 70%-80% of the total mass of the heterojunction photocatalyst. The preparation method comprises the following steps: S1, preparing bismuth vanadate by a hydrothermal method; S2, preparing the heterojunction photocatalyst, wherein adding BiVO4 into distilled water, carrying out ultrasonic dispersion, adding a certain amount of AgNO3 solution under the condition of magnetic stirring, slowly dropwise adding a certain amount of K2CrO4 solution to generate a brick red precipitate, continuously stirring to react for 1-2 hours, standing, precipitating, aging for 12-24 hours, centrifuging, washing with water for 6times, and carrying out vacuum drying. Compared with a traditional deposition method, the heterojunction formed by the selective adsorption deposition method is better in stability, higher in interface bonding degree and higher in visible light catalytic activity.

The invention provides a Co0.8Ni0.2TaO6 photocatalyst with a visible light response. The microstructure of the photocatalyst is porous micro/nano spheres of which the particle sizes are 5-10nm; and the diameters of the porous micro/nano spheres are 0.5-2 microns. The photocatalyst is prepared through sol-gel reaction, spray drying and burning of tantalum chloride, nickel acetate and cobalt nitrate as main reaction materials according to the stoichiometric ratio of a nickel element, a cobalt element and a tantalum element in the Co0.8Ni0.2TaO6. The preparation method is simple in preparation process, relatively low in cost, low in energy consumption; and the prepared photocatalyst has a good catalytic effect, has relatively high catalytic water decomposition efficiency under visible light radiation, and has potential application prospect in the field of hydrogen production from photocatalytic water splitting and water treatment.