32results about How to "Optimizing the band structure" patented technology

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 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 invention belongs to two-dimensional MoS 2 The technical field of preparation of base nanocomposite materials relates to a hollow sandwich laminated molybdenum disulfide based nanocomposite material and its preparation method. It is a hollow structure and includes carbon layers, MoS 2 layers and carbon layers. Using SiO 2 The microspheres are used as templates, which are sequentially coated with carbon layers, MoS 2 layer and carbon layer, then etched SiO 2 Hollow sandwich structure MoS was prepared 2 based nanocomposites. The unique hollow sandwich laminated structure of the obtained product is conducive to exposing more active sites, improving electrical conductivity, reducing agglomeration, and improving the electrocatalytic performance of the material. Therefore, the preparation of this composite material offers the possibility of its potential application in many fields.

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 invention belongs to the technical field of new materials, and more particularly relates to a covalent triazine framework polymer as well as a preparation method and application thereof. Accordingto the preparation method, a first monomer, a second monomer, a solvent and a catalyst are uniformly mixed for a reaction, and the reaction product is separated and purified to obtain the covalent triazine framework polymer, wherein the catalyst is a strong base with a base pKa being greater than 14; the first monomer is a monomer containing alpha-C and functional groups; the first monomer contains at least two of the functional groups; the functional group is an aldehyde group or a functional group capable of being converted into the aldehyde group by oxidation or reduction; and the second monomer is a multi-amidine compound. By adopting the method, not only is the monomer range of the existing reported synthesized covalent triazine framework greatly expanded, but also the reduction of the cost and limitation of the synthesis is facilitated; when the covalent triazine framework polymer is applied to photocatalytic decomposition of water for producing hydrogen, a multi-level pore structure of the material facilitates the generation and separation of photon-generated carriers, and reduces the recombination of the photon-generated carriers, so that the photoelectric performance andcatalytic efficiency of a semiconductor are improved.

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 relates to an n-p heterogeneous core-shell array gas-sensing material and a preparation method, in particular to a p-type nano-NiO as the core and an n-type nano-SnO 2 The core-shell monomer is a shell, and the whole is a highly ordered nano-array of NiO@SnO 2 Core-shell array gas-sensing material and preparation method. On the one hand, the gas-sensitive material of the invention avoids the depletion of interface electrons caused by the direct exposure of the p-type NiO in the core layer to the air; on the other hand, it utilizes the n-type SnO in the shell layer 2 The energy band structure of the gas-sensing material is improved, and the overall ordered array increases the active contact point, which improves the sensitivity of the gas-sensing material to gas. The method adopted in the present invention has a wide range of sources of raw materials and low prices; the obtained n-p heterogeneous NiO@SnO 2 The core-shell array gas-sensing material has high sensitivity and strong selectivity.

The invention claims to protect a low-power-consumption waveguide photodetector structure with optical isolation between the photosensitive mesa and the N-contact mesa. The structure integrates the light waveguide and the photodiode on a semi-insulating substrate. Among them, the photodiode has an optimized energy band structure, doping distribution and epitaxial layer thickness, mainly including a non-depleted P-type light absorption layer with a linear gradient doping distribution, and an N-type electron collection layer (non-depleted) with a linear gradient doping distribution. light absorbing layer), and a graded bandgap spacer layer with a sandwich dipole doping profile between the absorbing layer and the collecting layer. By making a groove on the N mesa and depositing a metal thin film electrode to optically isolate the photosensitive mesa from the N contact mesa, thereby improving the light confinement of the optical waveguide; making a mesa isolated from the N mesa at the end of the optical waveguide and depositing The upper metal thin film is used as a light reflector to increase the effective absorption length of the device, which is a technical solution to alleviate the mutual restriction between the bandwidth of the photodetector and the quantum efficiency.

The invention discloses an enol-ketone type covalent organic framework / graphite-phase carbon nitride composite photocatalyst and its preparation method and application. The composite photocatalyst includes graphite-phase carbon nitride on which enol-ketone is loaded covalent organic framework. The preparation method comprises mixing graphite-phase carbon nitride dispersion liquid with enol-ketone covalent organic skeleton, ultrasonication and stirring to obtain the composite catalyst. The enol-ketone type covalent organic framework / graphite phase carbon nitride composite photocatalyst of the present invention has high specific surface area, many reaction active sites, wide light absorption range, low electron-hole pair recombination rate, good photocatalytic performance, It has the advantages of good stability and environmental protection, and can be widely used to degrade organic pollutants, and the degradation effect is good, so it has good application value and application prospect. The preparation method of the invention has the advantages of simple process, convenient operation, readily available raw materials, low cost, high preparation efficiency, high yield, etc., is suitable for large-scale preparation, and is beneficial to industrialized production.

The invention provides a quantum dot, its preparation method and a photoelectric device. The preparation method of II‑III‑V‑VI quantum dots comprises: preparing the first nanocluster, the second nanocluster and the third nanocluster, the first nanocluster is III‑V nanocluster, the second nanocluster The cluster is III‑II‑V nanocluster, and the third nanocluster is III‑II‑VI nanocluster; the first nanocluster is mixed with a non-coordinating solvent to form the first quantum dot solution; the second nanocluster The cluster is mixed with the first quantum dot solution and heated to form the second quantum dot solution; the third nanocluster and the second quantum dot solution are mixed and heated to form the third quantum dot solution, and the third quantum dot in the third quantum dot solution is II ‑III‑V‑VI quantum dots. Mixing and adding each nanocluster one by one can effectively dope, improve the energy band structure, reduce surface defects and dangling bonds, so that the composition structure can be adjusted and the size uniformity of quantum dots can be improved.

The invention relates to the technical field of photocatalysis, in particular to a B, S co-doped carbon nitride nanotube photocatalyst, a preparation method and an application. In the method, a rod-shaped intermediate with a regular shape is firstly obtained by a low-temperature hydrothermal method, and then calcined in a tube furnace to obtain B, S co-doped carbon nitride with a tubular structure. Utilizing the characteristics of the tubular structure itself and the band structure change caused by the introduction of B and S elements, the existing photocatalysts solve the problems of low utilization rate of visible light, few exposed active sites, and low degradation efficiency of high-concentration organic dyes.