19 results about "Electron hole recombination" patented technology

The invention discloses a preparation method of a pyrenyl covalent organic framework material and application of the pyrenyl covalent organic framework material in photocatalytic hydrogen production reaction, and belongs to the field of heterogeneous catalysis. The novel pyrenyl COFs photocatalyst is synthesized by regulating and controlling the quantity of triphenylamine and integrating triphenylamine monomers with different contents into a pyrenyl covalent organic framework (COF) skeleton. The preparation method is simple to operate, mild in reaction condition, short in reaction time and high in repeatability, the obtained pyrenyl COFs have good light capture capacity and photon-generated carrier separation characteristic, electron-hole recombination can be effectively reduced, the excited state service life is prolonged, the reaction efficiency of photocatalytic hydrogen production is improved, and potential application prospects are achieved.

The application provides a LED chip with reverse polarity and small hole light emission and a manufacturing method thereof. The epitaxial layer of the LED chip comprises a P-type window layer and an MQW light emitting layer. The doping concentration of a first region in the P-type window layer is greater than that of a second region, which can limit current expansion and improve light emitting efficiency. An ODR dielectric film layer and an ODR metal reflection layer form an ODR mirror at the bottom of the epitaxial layer. An insulating passivation layer and an N electrode on the sidewall of the epitaxial layer can form an ODR mirror on the sidewall of the epitaxial layer. The N electrode also has a first hollow region. The ODR mirror can be used to reflect light, so that the light emitted by the MQW light emitting layer is only emitted from the first hollow region, and stray light emitted by the sidewall is suppressed. In addition, the orthographic projection of the first hollow region in the first direction completely covers the P ohmic contact metal unit, so that the electron hole recombination region is located in the MQW light emitting layer under the orthographic projection of the first hollow region, and the light emitting efficiency is further improved.

The application discloses a Bi2Sn2O7-Mo2C-In2S3 heterojunction photocatalyst and a preparation method thereof. First, a Bi2Sn2O7-Mo2C intermediate is prepared by using a Bi2Sn2O7 precursor; then, In2S3 is in-situ grown on the intermediate to obtain Bi2Sn2O7-Mo2C-In2S3. Mo2C is used to connect Bi2Sn2O7 and In2S3, and O-C-Mo-S chemical bonds are formed between Mo2C and the two, thereby constructing a heterostructure with a close interface contact; the chemical bonds serve as an electron transmission bridge to accelerate the migration of photo-generated carriers, and the local photo-thermal effect of Mo2C under visible light / near-infrared light irradiation further promotes the interface transmission of the carriers. The synergistic effect of the above-mentioned double effects significantly inhibits the electron-hole recombination, greatly improves the photo quantum efficiency and the photocatalytic activity, and makes the catalyst have a wide application prospect in the field of photocatalysis such as energy conversion and environmental governance.

The present application relates to a kind of 1D / 2D double heterojunction catalyst and its preparation method and its application in photo-assisted high iodate activation degradation bisphenol A.The preparation method of the present application: concentrated hydrochloric acid solution and LiF are mixed, Ti3AlC2 is added, heated reaction, solid-liquid separation is taken solid phase, after washing to neutral, dispersed in ethanol, to obtain MXene ethanol solution;Cerium source aqueous solution is added to MXene ethanol solution and mixed in liquid nitrogen, to obtain mixed solution;Organic ligand, ethanol and pure water are mixed to obtain mixed solution, the mixed solution and mixed solution are mixed and heated, solid-liquid separation is taken precipitate, freeze-drying is obtained powder;The obtained powder is heated and calcined under inert atmosphere, to obtain 1D / 2D double heterojunction catalyst.The present application effectively inhibits photo-generated electron hole recombination by constructing double heterojunction, while realizing ultrafast electron transfer, to enhance oxidation, realizes the high-efficiency photocatalytic activity of "1+1>2".

This invention relates to a composite photocatalytic material with optimized electron transport pathways, its preparation method, and its applications. The purpose of this invention is to address the problems of high electron-hole recombination rates and difficulty in efficiently removing recalcitrant organic matter from water using existing photocatalytic technologies. The composite photocatalytic material with optimized electron transport pathways includes an active component and an electron-accepting platform coupled thereto, forming a stable interfacial contact structure between the active component and the electron-accepting platform. The active component is bismuth oxyiodide; the electron-accepting platform is Magnéli phase titanium suboxide. The composite photocatalytic material prepared by this invention can achieve highly efficient photocatalytic oxidation removal of organic pollutants without the addition of external chemical reagents, and is particularly suitable for the treatment of antibiotics, pharmaceuticals, and other recalcitrant organic matter. This invention enhances the oxidation process by constructing an electron-accepting platform, offering advantages such as environmental friendliness, high carrier utilization efficiency, and wide applicability.

The embodiment of the utility model provides an LED chip, which comprises a substrate, a first reflecting layer, a first electrode, an epitaxial structure layer, a second reflecting layer and a second electrode, and is characterized in that a first type of ohmic contact is arranged in the first reflecting layer; the epitaxial structure layer is provided with an inclined side wall; the second electrode is provided with a first hollow area, and the first hollow area can be used for enabling light rays of the LED chip to be emitted only from the first hollow area, so that small-angle light emitting of the LED chip is achieved. The orthographic projection of the first type of ohmic contact on the surface where the second electrode is located is located in the first hollowed-out area, so that the electron-hole recombination area is located in the first hollowed-out area. The position of the first type ohmic contact is controlled and the first type ohmic contact is arranged in the first hollow area, so that the position of the electron hole recombination area is controlled, the electron hole recombination area and the first hollow area for emitting light are overlapped, the effective emission light power of the light emitted from the first hollow area is improved, and the high power of the LED chip is further realized.

A doped (ultra-)wide bandgap ((U)WBG) semiconductor can demonstrate photoconductivity when illuminated with sub-bandgap light. Forming a rectifying semiconductor-metal junction on a suitably doped (U)WBG semiconductor enables a photoconductive semiconductor switch (PCSS) actuated by visible light with strong photoresponsivity and fast operation. A PCSS realized in Ge-doped AlN achieves an on / off ratio over one million, and a photoresponsivity of 2.8 A / W under sub-bandgap illumination at center wavelength 455 nm and power density as low as 1 mW / cm2. The PCSS can be turned off in under a second with a bias pulse that accelerates electron-hole recombination in the rectifying junction, quenching persistent photoconductivity. It also enables a semiconductor photodetector can measure very bright light without saturation or damage, and at elevated temperature. Such a photodetector realized in Ge-doped AlN demonstrates linear, non-saturating photoresponse for visible illumination power density up to ≥10.8 W / cm2 and operating temperature up to ≥200° C.

This invention discloses an experimental method for measuring the electron-hole recombination emission rate. The apparatus for this method includes a laser chip (with an anti-reflection coating on only one end of its horizontal two-sided end face), a plano-convex lens, a polarizer, a fiber optic coupler, an optical fiber, and a spectrometer. The plano-convex lens, polarizer, plano-convex lens, and fiber optic coupler are placed sequentially on the same horizontal line on both sides of the chip. The fiber optic coupler is connected to the spectrometer via an optical fiber. First, energy is applied to the laser chip, causing it to emit light from both sides. The spectra from both sides are focused onto the fiber optic coupler by the plano-convex lens and then transmitted to the spectrometer via the optical fiber. By rotating the polarizer, different polarization spectra can be selected to obtain specific spectral images under transverse electric / magnetic field modes. Finally, by substituting the spectral data from both ends into the established formula, the electron-hole recombination rate of the laser chip can be calculated.

The invention provides a light emitting diode and a manufacturing method thereof, and belongs to the technical field of semiconductors. The light-emitting diode comprises an n-type semiconductor layer, a multi-quantum well layer, an insertion layer and a p-type semiconductor layer which are sequentially stacked together. Wherein each of the n-type semiconductor layer and the p-type semiconductor layer comprises a GaN layer; and the insertion layer is a C-doped GaN layer. According to the invention, the stark effect can be weakened, and the electron-hole recombination luminous efficiency in the multi-quantum well layer can be improved.

The invention relates to the field of photocatalysis, in particular to the field of organic matter selective oxidation coupling hydrogen production, and particularly relates to a photocatalyst as well as a preparation method and application thereof. The invention provides a photocatalyst with spatially separated oxidation sites and reduction sites constructed on a CdS rod, namely a metal sulfide reduction cocatalyst is loaded at two ends of the CdS rod, and a CoS oxidation cocatalyst is loaded on a rod body; under illumination, photo-induced electrons are rapidly migrated to reduction sites at the two ends to drive water splitting to produce hydrogen, and holes are synchronously migrated to oxidation sites to catalyze high-selectivity oxidation of benzyl alcohol into benzaldehyde. Hydrogen production and organic matter oxidation are synergistically coupled, so that electron-hole recombination is remarkably inhibited, and two high-value products are output at the same time. Experimental results show that the hydrogen production rate and the benzaldehyde generation rate of the CdS-MoS2-CoS spatial separation catalyst are respectively increased by 116 times and 22.8 times compared with those of an original CdS rod, and efficient separation and full utilization of photon-generated carriers by the CdS-MoS2-CoS spatial separation catalyst are fully verified.

The invention discloses a preparation method for in-situ construction of a Zr-MOF (at) Bi5O7I (at) LDH ternary core-shell heterojunction photocatalytic membrane, and belongs to the technical field of photocatalytic membranes. The method comprises the following steps: pretreating a PVDF membrane; growing a Zr-MOF (at) Bi5O7I binary heterojunction on the film through in-situ co-deposition; and finally, vertically growing an LDH shell on the surface of the binary heterojunction in situ through a hydrothermal method to form a core-shell structure. The core innovation point is that tight coupling and precise energy band matching of the three active components at the micro-nano scale are realized through a sequential in-situ growth technology, and the problems of non-uniform component dispersion and weak interface bonding of the traditional composite membrane are solved. Zr-MOF enhances adsorption and provides reaction sites, BiOI widens the light absorption range, LDH shell improves the catalytic stability, and Zr-MOF, BiOI and LDH shell synergistically construct an efficient Z-type charge transfer path and a strong built-in electric field to reduce the electron-hole recombination probability. The prepared photocatalytic membrane has a degradation rate of more than 96% for degradation-resistant organic matters such as RhB in 60 min, has excellent cycle stability, is easy to recover, has no secondary pollution, and has a wide application prospect in the field of deep water purification.

This invention discloses a method for preparing TCPP / Emodin composite photocatalysts and their antibacterial applications, belonging to the field of pharmaceutical antibacterial medicine. Addressing the issues of drug resistance easily induced by traditional antibiotics in treating bacterial infections, performance defects in existing photocatalysts, and insufficient antibacterial capacity of single antibacterial materials, this invention leverages the advantages of tetracarboxyphenylporphyrin (TCPP)—strong visible light capture ability and low photogenerated electron-hole recombination rate—and complements emodin's π-conjugated system and its structural advantage of promoting carrier migration. The two are covalently linked through a chemical coupling mechanism involving EDC / NHS synergistic activation of the carboxyl group. Through steps such as dissolution, mixing reaction, dialysis purification, and freeze-drying, spherical TCPP / Emodin composite nanomaterials with a particle size of 100-500 nm are obtained. This composite material reduces the photogenerated electron-hole recombination rate and improves carrier migration efficiency, efficiently generating ROS under visible light irradiation, and exhibits excellent photodynamic antibacterial properties.

The invention relates to an epitaxial structure and a manufacturing method thereof, a light-emitting chip and a display panel. The manufacturing method of the epitaxial structure comprises the following steps: providing a substrate, and sequentially growing a first semiconductor layer and an active layer on the substrate; growing a doped superlattice barrier layer on the active layer; growing a low-temperature doping layer on the doped superlattice barrier layer in a stepped gradient doping manner; and growing a second semiconductor layer on the low-temperature doping layer. According to the invention, the doped superlattice barrier layer is grown on the active layer, and the low-temperature doped layer is grown on the doped superlattice barrier layer in a stepped gradient doping manner, so that the energy barrier required by hole transition of the doped superlattice barrier layer and the low-temperature doped layer is reduced, and the hole mobility is improved; besides, electron holes are spatially separated by utilizing the structure of the doped superlattice barrier layer and the low-temperature doped layer, so that the electron holes are located in different material layers, and the probability that the electron hole pairs are compounded outside an active region is reduced.

The invention discloses a preparation method of a Ni-In2Se3-SnSe2 heterojunction photocatalyst. The preparation method comprises the following steps: synthesizing a Ni-In2Se3-SnSe2 precursor by adopting a one-step solvothermal method; and then, the precursor is subjected to calcination treatment under the protection of inert gas, and finally, the Ni-In2Se3-SnSe2 heterojunction photocatalyst is obtained. The core of the In2Se3-SnSe2 heterojunction is that dual regulation and control of an electronic structure and an interface of the In2Se3-SnSe2 heterojunction are synchronously realized through Ni doping. On one hand, Ni atoms replace part of In sites to form an electron trap, photo-induced electrons are effectively captured, and electron-hole recombination is inhibited; and on the other hand, lattice mismatch caused by Ni doping promotes formation of a stable In-Se-Sn interface chemical bond between In2Se3 and SnSe2, an efficient cross-interface charge transfer channel is constructed, and a carrier migration barrier is greatly reduced, so that synergistic improvement of the photon-generated carrier separation efficiency is realized. The method is simple in preparation process, mild and controllable in reaction condition and environment-friendly, and has a good industrial application prospect.

This disclosure relates to an ultraviolet light-emitting semiconductor chip comprising a translucent substrate and a plurality of semiconductor regions provided on the translucent substrate, each comprising a first semiconductor region, a second semiconductor region, and an active region interposed between the first and second semiconductor regions and emitting ultraviolet light through electron-hole recombination, wherein a mesa region is formed by removing a portion of the second semiconductor region, the active region, and the first semiconductor region, and a first electrode provided in the first semiconductor region exposed by removing a portion of the second semiconductor region, the active region, and the first semiconductor region, and electrically connected to the first semiconductor region, and a second electrode electrically connected to the second semiconductor region, wherein when the first electrode and the second electrode are viewed from above, they form a closed loop shape surrounding the mesa region so as to block moisture and gas, and an ultraviolet light-emitting semiconductor light-emitting element equipped therewith.

This invention discloses a two-dimensional layered Ta4C3-supported Bi2WO6 composite catalyst, its preparation method, and its applications. The invention involves etching the Al atomic layers in the MAX phase Ta4AlC3, then preparing a single-layer MXene material Ta4C3 through exfoliation, and finally generating Bi2WO6 nanospheres in situ on the Ta4C3 surface via a hydrothermal method to obtain the two-dimensional layered Ta4C3-supported Bi2WO6 composite catalyst. This two-dimensional layered Ta4C3-supported Bi2WO6 composite catalyst enhances the electron transfer capability of Bi2WO6, broadens the visible light absorption wavelength range of Bi2WO6, reduces the electron-hole recombination rate, and improves photocatalytic performance. Under 60 min of illumination, the degradation efficiency of the two-dimensional layered Ta4C3-supported Bi2WO6 composite catalyst reaches 65% for dodecylmorpholine, with no other energy consumption, making it safe and environmentally friendly. This is of great significance for the low-energy and pollution-free treatment of dodecylmorpholine, a flotation agent in salt lake brine.

The invention discloses a preparation method and application of a Fe / Cu / BiOCl composite photocatalyst, a Fe < 3 + > and Cu < 2 + > co-doped BiOCl composite photocatalyst is synthesized based on a simple one-step hydrothermal method, and the energy band structure of BiOCl can be effectively regulated and controlled by adjusting the doping proportion of Fe and Cu ions. Compared with undoped BiOCl and Fe / Cu single metal ion doped BiOCl, a Fe and Cu co-doped sample shows higher visible light absorption capacity and lower electron-hole recombination efficiency. When the doping molar ratio of Fe < 3 + > to Cu < 2 + > is 9: 1, the photocatalytic performance of the composite photocatalyst is optimal, and the removal rate of Cr (VI) reaches 91.3% after the composite photocatalyst is irradiated by visible light for 120 min and is remarkably higher than that of pure BiOCl (64.4%). In addition, the composite photocatalyst also shows good stability and recycling performance, and has potential application value in the field of water treatment.

The invention provides a porphyrin-based covalent organic framework photocatalyst and application of the porphyrin-based covalent organic framework photocatalyst to catalytic regeneration of coenzyme NADH, belongs to the technical field of photocatalysis, and aims to solve the technical problem of low efficiency of photocatalytic regeneration of coenzyme NADH. The two-dimensional porphyrin-based photocatalyst material with high crystallinity, high porosity and good stability is formed by covalent linkage of imine bonds formed by organic monomers through a Schiff base condensation reaction, the energy band gap of the two-dimensional porphyrin-based photocatalyst material is narrowed, the light absorption and utilization performance is high, the electron-hole recombination rate is low, and the electron transfer rate is high; the regeneration activity of the coenzyme NADH in the catalysis process can be enhanced. The porphyrin-based covalent organic framework photocatalyst has high selectivity and stability on catalytic regeneration of the coenzyme NADH under visible light, and the regeneration efficiency of the coenzyme NADH can reach 97% at most within 25 min.

The disclosure relates to a III-nitride semiconductor light emitting device comprising: a first semiconductor region having a first conductivity; a second semiconductor region having a second conductivity different from the first conductivity; and an active region interposed between the first and second semiconductor regions and generating light through electron-hole recombination wherein the active region includes a quantum well layer with an indium (In) content (x) corresponding to an emission wavelength below 500 nm and emits light with a wavelength exceeding 600 nm.