39results about How to "Optimizing the band structure" patented technology

The invention discloses an ultraviolet-light gallium nitride semiconductor light emitting diode with gradient electron barrier layers. By means of energy band engineering design and optimization, six kinds of superlattice-like AlGaN electron barrier layers with different changing types are introduced to an epitaxial structure of the light-emitting diode so as to realize the change of an aluminum component, so that the polarization effect in the electron barrier layers is changed, and high hole injection is realized so as to solve the problems of low P-type doping efficiency and insufficient hole concentration in the ultraviolet-light semiconductor light emitting diode.

The invention discloses a CIGS (copper indium gallium selenium) thin film solar cell and a preparation method thereof, and belongs to the technical field of the solar cell. The solar cell is formed by successively connecting a substrate, a metal anode, a light absorption layer, a buffer layer, a window layer, a transparent electrode layer and a grid-shaped metal cathode, wherein the light absorption layer consists of at least two layers of CIGS thin films of different energy gaps; and each CIGS single layer of the light adsorption layer is directly formed into the film by regulating the magnetron sputtering pressure, the temperature range and the power density, or a prefabricated layer is prepared by magnetron sputtering; and then, the prefabricated layer is subjected to selenylation processing to obtain the CIGS thin film at the temperature of 400-500DEG C under the protection of argon or nitrogen. Each single layer of CIGS thin film disclosed by the invention has different energy gaps, the shape of the energy band of the light absorption layer can be regulated in a combined mode, the collection and light spectrum response curve of a carrier can be both considered, and the absorption efficiency of the light absorption layer is improved by 30-50%. The CIGS thin film solar cell and the preparation method disclosed by the invention have the advantages of high cell photoelectric conversion efficiency, simple technology, simple required equipment and easiness in realizing mass production.

The present invention provides an AlGa-based semiconductor ultraviolet device for improving luminous efficiency and a preparation method thereof, and relates to the technical field of semiconductors.The epitaxial structure of the device comprises a substrate, an AlN buffer layer, an n-type AlGaN layer, an AlxGa1-xN / AlyGa1-yN luminescence active region, the last one AlGaN quantum barrier layer, ap-type AlGaN electron blocking layer, a p-type AlGaN layer and a contact layer, wherein 0.01<=x and y<=1. The luminescence active region comprises a plurality of quantum well layers and a plurality ofquantum barrier layers, the quantum well layers and the quantum barrier layers are alternately arranged, and the last one AlGaN quantum barrier layer is an aluminium ingredient gradient layer. The last one AlGaN quantum barrier layer of aluminium ingredient gradient is introduced in the ultraviolet device to optimize the energy band structure of the device, effectively improve the electron restriction effect and enhance the cavity injection efficiency so as to improve the quantum efficiency and the luminescence efficiency of the semiconductor ultraviolet device.

The invention relates to a hole compensation type skutterrudite thermoelectric material and a preparation method of the hole compensation type skutterudite thermoelectric material. The hole compensation type skutterudite thermoelectric material is shown in the following description: RyA(4-x)BxSb12 / z NC, wherein x is equal to or greater than 0.01 and equal to or less than 0.5, y is equal to or greater than 0.01 and equal to or less than 1 and z is equal to or greater than 0% and equal to or less than 10%; R is selected from at least one of the following group of elements: Ca, Ba, La, Ce, Pr, Nd and Yb; A is selected from at least one of the following group of elements: Fe, Co and Ni; B is selected from at least one of the following group of transition metal elements: Ti, V, Cr, Mn, Fe, Nb, Mo, Tc and Ru, and electron number of the element B is less than that of the element A; and NC is in phase II, wherein z is mole% in the phase II of the thermoelectric material. The invention also provides the preparation method of the hole compensation type skutterrudite thermoelectric material.

The invention discloses a method for improving perovskite performance by changing perovskite unit cell parameters. Ions, atoms or molecules are doped into a lattice structure of the perovskite material to change perovskite unit cell parameters, so that the energy band structure, the carrier mobility and the carrier lifetime of the perovskite material are improved, the luminescence characteristic,the microstructure morphology of the material, the stability of the material and the like are coordinated, and the performance of the perovskite material is further improved. The method comprises thefollowing steps: synthesizing a perovskite material with a chemical formula of ABX3, A2C1D1X6 or A2BxC1-xDX6 (0 < x < 1), and doping electrons, ions, atoms, molecules and the like into a perovskite structure to improve the performance and the stability of the perovskite structure. The method is low in cost and remarkable in effect, is suitable for preparing the high-quality and high-stability perovskite material and has industrial production potential. The obtained perovskite material can be applied to the fields of photoelectric, ferroelectric and piezoelectric functional devices such as perovskite solar cells, light emitting diodes, micro-sensing devices, lasers, photoelectric detectors, photosensitive diodes and thin film transistors.

The invention relates to a low-power-consumption waveguide optical detector structure of optical isolation between a photosensitive table board and an N contact table board. In the structure, an optical waveguide and a photodiode are integrated on a semi-insulating substrate. The photodiode has an optimized energy band structure, doping distribution and an epitaxial layer thickness. A non-depletion P-type light absorption layer with linear gradient doping distribution, an N-type electron collection layer (non-light absorption layer) with linear gradient doping distribution, and a band gap gradient interval layer with sandwich dipole doping distribution between the absorption layer and the collection layer are mainly included. The photosensitive table board and the N contact table board areoptically isolated by making a groove in the N table board and depositing a metal film electrode so that limitation of the optical waveguide on light is improved. The table board isolated from the Ntable board is manufactured at a tail end of the optical waveguide, and the metal film is deposited to serve as an optical reflector so that an effective absorption length of a device is increased, and a technical scheme for relieving mutual restriction of an optical detector bandwidth and quantum efficiency is provided.

The invention discloses a molybdenum carbide modified tubular carbon nitride photocatalytic material and a preparation method and application thereof. The molybdenum carbide modified tubular carbon nitride photocatalytic material comprises molybdenum carbide and tubular carbon nitride, wherein the surface of the tubular carbon nitride is modified with the molybdenum carbide. The preparation methodcomprises the steps: suspending the tubular carbon nitride in methanol, so as to obtain a suspension; dispersing the molybdenum carbide in the suspension, carrying out intensive mixing, and carryingout drying, thereby obtaining the molybdenum carbide modified tubular carbon nitride photocatalytic material. According to the molybdenum carbide modified tubular carbon nitride photocatalytic material disclosed by the invention, an energy band structure of the carbon nitride is improved to form molybdenum carbide / carbon nitride heterojunction, so that the effective separation of photoproduction electron-hole pairs is achieved, the utilization efficiency of photoproduction electron-holes is increased, and the effect of photocatalytic degradation is promoted; the molybdenum carbide modified tubular carbon nitride photocatalytic material can be applied to degradation of antibiotics or dyes in wastewater.

The invention discloses a hollow tubular sulfur-doped carbon nitride / graphite-phase carbon nitride homojunction photocatalyst, and a preparation method and application thereof. The photocatalyst takeshollow tubular sulfur-doped carbon nitride as a carrier; graphite-phase carbon nitride is loaded on the hollow tubular sulfur-doped carbon nitride; and the hollow tubular sulfur-doped carbon nitrideand the graphite-phase carbon nitride form a homojunction. The preparation method comprises the following steps: mixing and stirring melamine and trithiocyanuric acid, carrying out a hydrothermal reaction to obtain a solid tubular melamine / trithiocyanuric acid compound, modifying the surface of the solid tubular melamine / trithiocyanuric acid compound with urea, and carrying out calcining to obtainthe product. The hollow tubular sulfur-doped carbon nitride / graphite-phase carbon nitride homojunction photocatalyst can efficiently degrade tetracycline hydrochloride or tetracycline-containing wastewater with a pH value of 2-11, and has the advantages of high light absorption capacity, low photo-induced electron-hole recombination rate, good photocatalytic performance, good stability, applicability to a wide pH scope and the like.

The invention provides a quantum dot and a preparation method thereof and a photoelectric device. The preparation method of the II-III-V-VI quantum dot includes the following steps that a first nano cluster, a second nano cluster and a third nanao cluster are prepared, wherein the first nano cluster is III-V nano cluster, the second nano cluster is III-II-V nano cluster, and the third nano clusteris III-II-VI nano cluster; the first nano cluster is mixed with a non-coordination solvent to form a first quantum dot solution; the second nano cluster is mixed with the first quantum dot solution and then heated to form a second quantum dot solution; the third nano cluster is mixed with the second quantum dot solution and heated to form a third quantum dot solution, wherein the third quantum dot in the third quantum dot solution is the II-III-V-VI quantum dot. By mixing and adding the nano clusters one by one, effective doping can be achieved, the band structure is improved, and the surfacedefects and dangling bonds are reduced, so that the composition structure is adjustable and the size uniformity of the quantum dot is improved.

The invention belongs to the technical field of preparation of two-dimensional MoS2-based nano composite materials, and relates to a molybdenum disulfide-based nano composite material with a hollow sandwich laminated structure and a preparation method of the molybdenum disulfide-based nano composite material, and the molybdenum disulfide-based nano composite material is of a hollow structure and sequentially comprises a carbon layer, a MoS2 layer and a carbon layer from inside to outside. SiO2 microspheres are adopted as a temboard, the carbon layer, the MoS2 layer and the carbon layer sequentially coat the temboard, and then the MoS2-based nano composite material with the hollow sandwich laminated structure is prepared after SiO2 is etched. The obtained product has a unique hollow sandwich laminated structure, so that more active sites can be exposed, the conductivity is improved, agglomeration is reduced, and the electro-catalytic performance of the material is improved. Therefore, the preparation of the composite material provides possibility for potential application of the composite material in various fields.

The invention provides a carbon nitride based material for photocatalytic water total decomposition as well as preparation and application thereof. The carbon nitride based material for the photocatalytic water total decomposition, provided by the invention, is characterized by comprising a carbon nitride carrier; and monatomic palladium is loaded on the carbon nitride carrier. Compared with puregraphite-phase carbon nitride and palladium nanoparticle loaded carbon nitride, the carbon nitride based material provided by the invention has better catalytic activity and stability.

The invention relates to the technical field of photocatalysis, in particular to a preparation method of a CdS nanobelt for producing H2O2. The uniform CdS nanobelt is directly obtained by a solvothermal method of an alkaline organic solvent. By utilizing the energy band structure change caused by the alkalized CdS nanobelt, the problems of low visible light utilization rate, few exposed active sites, low H2O2 production efficiency and the like of the existing photocatalyst are solved.

The invention belongs to the field of materials, and particularly relates to an in-situ heterojunction photocatalyst and a preparation method and application thereof. The tungsten heterojunction photocatalyst provided by the invention is of a core-shell structure, wherein the inner layer and the outer layer of the photocatalyst are tungsten semiconductor oxides with different structures. Through diffusion of doping ions in crystal lattices, the shell structure is controllably adjusted under the induction of the doping ions, so tungsten heterojunction photocatalysts with different junction structures are obtained, and the toptimization of photo-induced electron-hole transport, separation efficiency and an energy band structure is realized; and thus, the photocatalytic performance of the heterojunction photocatalyst is remarkably improved. Results in embodiments show that when the heterojunction photocatalyst provided by the invention is used for photocatalytic decomposition of water, the generation amount of oxygen can reach 210 [mu]mol / h / g; when the heterojunction photocatalyst provided by the invention is used for degrading azo macromolecular rhodamine B (RhB), the degradation rate of RhB with a high concentration of 100 mg / L reaches 93% after degrading for 60 minutes, and the degradation rate of formaldehyde with a high concentration of 10 mg / L reaches 89% after degrading for180 minutes.

The invention discloses an enol-ketone covalent organic framework / graphite phase carbon nitride composite photocatalyst as well as a preparation method and application thereof. The composite photocatalyst comprises graphite phase carbon nitride, and an enol-ketone covalent organic framework is loaded on the graphite phase carbon nitride. The preparation method comprises the following steps: mixing a graphite phase carbon nitride dispersion liquid with the enol-ketone covalent organic framework, and carrying out ultrasonic treatment and stirring to obtain the composite catalyst. The enol-ketone type covalent organic framework / graphite-phase carbon nitride composite photocatalyst has the advantages of high specific surface area, multiple reaction active sites, wide light absorption range, low electron-hole pair recombination rate, good photocatalytic performance, good stability, environmental protection and the like, can be widely used for degrading organic pollutants, has a good degradation effect, and can be widely applied to degradation of organic pollutants. Good application values and application prospects are realized. The preparation method disclosed by the invention has the advantages of simple process, convenience in operation, easily available raw materials, low cost, high preparation efficiency, high yield and the like, is suitable for large-scale preparation and is beneficial to industrial production.

The invention discloses an enol-ketone covalent organic framework / amino-functionalized zirconium-based metal organic framework composite photocatalyst as well as a preparation method and an application thereof. The composite photocatalyst comprises an enol-ketone covalent organic framework and an amino-functionalized zirconium-based metal organic framework growing on the surface of the enol-ketone covalent organic framework in situ. The preparation method comprises the following steps: mixing 2-aminoterephthalic acid, an enol-ketone covalent organic framework and zirconium tetrachloride, and carrying out a hydrothermal reaction. The composite photocatalyst has the advantages of high specific surface area, multiple reaction active sites, wide light absorption range, low electron-hole pair recombination rate, good photocatalytic performance, good stability and the like, is a novel photocatalyst with stable structure and excellent catalytic performance, can effectively degrade organic pollutants, and is high in use value and good in application prospect; and the preparation method has the advantages of being simple in process, convenient to operate, 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 facilitates industrial production.

The invention relates to a nickel sulfide / cadmium sulfide / sulfur-doped graphite-like carbon nitride double-heterojunction composite photocatalyst and a preparation method thereof, and belongs to the technical field of photocatalysis. S-doped g-C3N4 nanosheet powder, nickel chloride hexahydrate, cadmium acetate, thioacetamide, cetyltrimethylammonium bromide and polypyrrole are uniformly mixed in ammonia water; the molar ratio of the nickel chloride hexahydrate to the cadmium acetate to the thioacetamide is (1-5): (1-6): (2-12); the precursor solution is subjected to heat preservation treatment at the temperature of 120-180 DEG C to obtain a reaction solution, precipitates in the reaction solution are washed and then dried, separation and transmission of photogenerated charges are effectively promoted, a rapid charge transfer way is provided for rapid migration of electrons-holes in the catalysis process through a double-heterogeneous interface, and therefore the purpose of accelerating separation of the photogenerated charges is achieved; finally, the photocatalytic hydrogen evolution activity of the g-C3N4 can be obviously improved.

The invention discloses a method for degrading organic pollutants in water by using a WO3-TiO2 photocatalytic material based on SiO2 aerosol. The photocatalytic material can effectively utilize solarlight to degrade petroleum contaminants in surface water bodies, can be used for surface water pollution control, and belongs to the field of water pollution control. The method mainly utilizes the very-large specific surface area of the SiO2 aerosol and the higher visible light utilization efficiency of WO3 and efficiently utilizes sunlight to generate free radicals to degrade the petroleum contaminants in the water bodies. The method has the following advantages that (1) the prepared material has the very-large specific surface area which is larger than 400 m<2> / g, and a large number of exposed active sites can achieve efficient free radical generation and pollutant degradation; (2) the combination of the SiO2 aerosol and the TiO2 can effectively reduce the recombination (energy loss) ofphotogenerated electron-hole during catalysis, while doping of a small amount of WO3 can achieve efficient solar light utilization efficiency, and the organic pollutants in the water bodies are efficiently removed under energy-saving and environment-friendly conditions; (3) the material has high stability in water, is easy to recycle, and reduces the generation of secondary pollution.

The invention relates to an antistatic LED device and a preparation method thereof. The device structure sequentially comprises a substrate layer; a first semiconductor layer; a first stress release layer; a second stress release layer; an active layer; a second semiconductor layer; an electrode layer; the first anti-static layer is located between the first stress release layer and the second stress release layer, and the first anti-static layer is an n-type doped GaN layer; wherein the first semiconductor layer and the second semiconductor layer are semiconductor layers with opposite conduction types; the silicon doping concentration of the first antistatic layer is different from the silicon doping concentration of the first stress release layer, and the silicon doping concentration of the first antistatic layer is different from the silicon doping concentration of the second stress release layer. The antistatic LED device provided by the invention can effectively improve the antistatic capability and the electrical property of the LED device, thereby improving the reliability and prolonging the service life of the device in various applications.

The invention provides a hole transport material of a perovskite solar cell, and a preparation method and an application of the hole transport material. A hole transport material composition comprisesan inorganic hole transport material and rare metal elements; and a molar ratio of metal elements in the inorganic hole transport material to the rare metal elements is N : 1 (20<=N<=100,000). The hole transport layer of the perovskite solar cell is prepared from the hole transport material composition of the perovskite solar cell. The perovskite solar cell is high in stability and high in conversion efficiency.

The application provides a porous carbon nitride photocatalyst and a preparation method and application thereof, and the porous carbon nitride photocatalyst is prepared by the following steps: uniformly mixing and grinding a nitrogen-rich organic material precursor and a gaseous template agent ammonium chloride; performing high-temperature treatment on the mixed precursor by using a microwave-assisted thermal polymerization method, and cooling to room temperature after the reaction is completed; and grinding, washing and drying the obtained product to collect the GCN. The method uses a one-step microwave-assisted thermal polymerization method to make melamine and the mixed precursor of ammonium chloride react, and the rapid thermal shock effect of the microwave field is used to induce the material to form a porous structure; the ammonium chloride is decomposed at high temperature to generate a bubble effect, which effectively inhibits the excessive stacking of carbon-nitrogen planes, induces the formation of a hierarchical porous structure and introduces rich edge defects. The degradation rate constant of the catalyst for cephalosporin antibiotics can reach 4.16 times that of pure g-C3N4, the catalyst has extremely excellent specific removal capacity for tetracycline, has good chemical stability and broad applicability, and can efficiently realize the deep purification of pollutants in water.

The invention discloses a molybdenum carbide modified tubular carbon nitride photocatalytic material and a preparation method and application thereof. The molybdenum carbide modified tubular carbon nitride photocatalytic material comprises molybdenum carbide and tubular carbon nitride, wherein the surface of the tubular carbon nitride is modified with the molybdenum carbide. The preparation methodcomprises the steps: suspending the tubular carbon nitride in methanol, so as to obtain a suspension; dispersing the molybdenum carbide in the suspension, carrying out intensive mixing, and carryingout drying, thereby obtaining the molybdenum carbide modified tubular carbon nitride photocatalytic material. According to the molybdenum carbide modified tubular carbon nitride photocatalytic material disclosed by the invention, an energy band structure of the carbon nitride is improved to form molybdenum carbide / carbon nitride heterojunction, so that the effective separation of photoproduction electron-hole pairs is achieved, the utilization efficiency of photoproduction electron-holes is increased, and the effect of photocatalytic degradation is promoted; the molybdenum carbide modified tubular carbon nitride photocatalytic material can be applied to degradation of antibiotics or dyes in wastewater.

The invention discloses a preparation method of a microsphere type nano composite material, which comprises the following steps: preparing ZCS-Vs powder by using Zn (AC) 2.2 H2O, Cd (NO3) 2.4 H2O and CH4N2S as raw materials and using a mixed solution of deionized water and hydrazine hydrate as a solvent through a solvothermal method; glucose, NiCl2. 6H2O and urea are used as raw materials, deionized water is used as a solvent, and NiO / Ni-C powder is prepared by combining a solvothermal method with a nitrogen atmosphere calcination method; and placing the NiO / Ni-coated C in a ZCS-Vs aqueous solution for ultrasonic dispersion, uniformly stirring, and annealing in an air atmosphere to obtain the NiO / Ni-coated ZCS-Vs nano composite material. The nano composite material prepared by the embodiment of the invention has the advantages of stable structure, strong visible light response capability, high electron transfer efficiency, rich catalytic active sites and the like, and can be applied to efficient hydrogen production by solar energy and photocatalysis.

The invention provides a near ultraviolet LED adopting an MOCVD technology and a preparation method thereof, and relates to the technical field of semiconductors. The near ultraviolet LED comprises asubstrate, and a buffer layer, a high-temperature layer, an n-type AlmGa1-mN layer, a light-emitting active region, a p-type electron blocking layer, a p-type AlnGa1-nN layer and a contact layer whichare sequentially grown on the substrate, wherein the material of the light-emitting active region comprises In < x > Ga < 1-x > N and Al < y > Ga < 1-y > N, the material of the p-type electron blocking layer comprises Al < y 1> In < x 1> Ga < 1-y1-x1 > N, 0.001<=x<y<=1, and y, m and n are all less than y1. The near ultraviolet LED can effectively improve the electron limiting effect and the holeinjection efficiency, so that the quantum efficiency and the light emitting efficiency of the device are improved.

The present disclosure relates to skutterudite thermoelectric materials of hole- compensated type and method of making the same, providing a skutterudite thermoelectric material of hole-compensated type having a composition represented by the following formula RyA4-xBxSb12 / z NC, where 0.01 = x =0.5, 0.01 = y =1, 0% = z = 10%; R is at least one element selected from the group consisting of Ca, Ba, La, Ce, Pr, Nd and Yb; A is at least one element selected from the group consisting of Fe, Co and Ni; B is at least one transition metal element selected from the group consisting of Ti, V, Cr, Mn, Fe Nb, Mo, Tc and Ru such that element(s) B have fewer electrons than element(s) A; and NC is a second phase where z is a mole percentage of the second phase in the thermoelectric material. Also disclosed are methods of making a skutterudite thermoelectric material of hole-compensated type.

The present invention belongs to the technical field of new materials, and more specifically, relates to a covalent triazine framework polymer, its preparation method and application. Mix the first monomer, the second monomer, the solvent and the catalyst evenly, react, and obtain a covalent triazine framework polymer after separation and purification; the catalyst is a strong base with a base pKa greater than 14; the first monomer is a polymer containing α -C and functional group monomer; the first monomer contains at least two of the functional groups; the functional group is an aldehyde group or a functional group that can be converted into an aldehyde group through oxidation or reduction; the second monomer It is a polyvalent amidine compound; this method can not only greatly expand the monomer range of the currently reported covalent triazine framework for the synthesis of covalent triazine frameworks, but also help to reduce the cost and restrictions of synthesis and apply it to photocatalytic water splitting for hydrogen production. The hierarchical porous structure of the material is conducive to the generation and separation of photogenerated carriers and reduces the recombination of photogenerated carriers, thereby improving the photoelectric performance and catalytic efficiency of the semiconductor.

The invention discloses an ultraviolet-light gallium nitride semiconductor light emitting diode with gradient electron barrier layers. By means of energy band engineering design and optimization, six kinds of superlattice-like AlGaN electron barrier layers with different changing types are introduced to an epitaxial structure of the light-emitting diode so as to realize the change of an aluminum component, so that the polarization effect in the electron barrier layers is changed, and high hole injection is realized so as to solve the problems of low P-type doping efficiency and insufficient hole concentration in the ultraviolet-light semiconductor light emitting diode.

The invention discloses a treating agent for efficiently removing heavy metals in industrial sewage and a preparation method of the treating agent, and belongs to the technical field of sewage treatment. The treatment agent is prepared by compounding modified charcoal and Co-Cu doped nano titanium dioxide according to a ratio. The modified biochar has more active sites and specific surface area and can better adsorb various heavy metal ions in sewage, and then the Co-Cu doped nano titanium dioxide reduces the heavy metal ions enriched on the surface of the biochar into harmless substances by utilizing photocatalysis. The Co-Cu doped nano titanium dioxide can generate more photo-induced electrons and holes so as to initiate a more efficient oxidation-reduction reaction, the Co-Cu doped nano titanium dioxide and the Co-Cu doped nano titanium dioxide have a synergistic effect, an excellent effect of removing heavy metal ions in water is achieved, and the Co-Cu doped nano titanium dioxide has a good market application prospect.