32results 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 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 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 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 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 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 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 invention relates to an n-p heterogeneous core-shell array gas sensitive material and a preparation method thereof, in particular to a NiO@SnO2 core-shell array gas sensitive material which uses p-type nano NiO as a core and n-type nano SnO2 as a shell and is a highly ordered nano array on the whole and a preparation method thereof. On one hand, the gas sensitive material provided by the invention avoids the exhausting of interface electrons due to direct exposure of the p-type NiO in the core layer to the air. On the other hand, the energy band structure of the gas sensitive material is improved by using the n-type SnO2 in the shell layer, and the overall ordered array increases the number of active contact points and improves the gas sensitivity of the gas sensitive material. The method provided by the invention has the advantages of a wide range of raw materials and low price. The n-p heterogeneous NiO@SnO2 core-shell array gas sensitive material obtained has high sensitivity and strong selectivity.