201 results about "Silicon quantum dots" patented technology

Due to the indirect transition characteristic of silicon semiconductors, the light extraction efficiency of a silicon-based light emitting diode is lower than that of a compound semiconductor-based light emitting diode. For this reason, there are difficulties in practically using and commercializing silicon-based light emitting diodes developed so far. Provided is a silicon-based light emitting including: a substrate with a lower electrode layer on a lower surface thereof; a lower doped layer that is formed on an upper surface of the substrate and supplies carriers to an emitting layer; the emitting layer that is a silicon semiconductor layer including silicon quantum dots or nanodots formed on the lower doped layer and has a light-emitting characteristic; an upper doped layer that is formed on the emitting layer and supplies carriers to the emitting layer; an upper electrode layer formed on the upper doped layer; and a surface structure including a surface pattern formed on the upper electrode layer, a surface structure including an upper electrode pattern and an upper doped pattern formed by patterning the upper electrode layer and the upper doped layer, or a surface structure including the surface pattern, the upper electrode pattern, and upper doped pattern, wherein the surface structure enhances the light extraction efficiency of light emitted from the emitting layer according to geometric optics.

The invention discloses a photoelectric detector based on graphene/boron-doped silicon quantum dots/silicon and a preparation method thereof. The photoelectric detector comprises an n type silicon substrate, a top electrode, a graphene film, a boron-doped silicon quantum dot film, and a bottom electrode. The photoelectric detector can carry out wide spectral detection, and a problem of low infrared detection response of a traditional silicon-based PIN junction is solved. According to the detector, graphene is used as an active layer and a transparent electrode, a dead layer is eliminated, and the absorption of incident light is enhanced. The boron-doped silicon quantum dot film is in the middle, the influence of a silicon surface state is reduced, and the reverse saturation current is suppressed at the same time. Under a certain reverse bias voltage effect, collision ionization is generated by photon-generated carriers and silicon lattice, and a high photoelectric response is obtained. The photoelectric detector and the preparation method have the advantages of a simple preparation process, low cost, a high response degree, fast response speed, a large internal gain, a small switching ratio, and easy integration.

The invention belongs to the technical field of the preparation methods of the nanomaterials and specifically discloses a method for preparing water-soluble fluorescent silicon quantum dots by using a hydrothermal process. The method comprises the steps of firstly introducing an amino silane and a reducing agent into a solvent in which nitrogen is introduced and mixing, continuing introducing the nitrogen for protection for a while, next, transferring to a hydrothermal reaction kettle, and heating for reacting for a while, thereby obtaining the fluorescent silicon quantum dots having excellent chemical properties. The method has the advantages of low raw material cost due to the adoption of the amino silane as a silicon source, simple operation steps, direction synthesis in water phase, easy large-scale production, and being green and environment; the obtained quantum dots have high quantum yield and excellent chemical characteristics, and are small in particle size, evenly in distribution, non-toxic, good in biocompatibility and acid resistance; besides, the quantum dots have pH sensitive characteristic in a certain range, and can be widely applied to the biochemical and biomedical sensing fields such as biochemical detection, drug analysis, cell and living imaging and targeting tracing and also can be used as photovoltaic conversion and light-emitting display materials.

The invention provides application of water-soluble silicon quantum dots as drug carriers. A preparation method of a silicon quantum dot-drug molecule composition comprises the following concrete steps: preparing aminated silicon quantum dots, performing maleimide treatment on the surfaces of the aminated silicon quantum dots, and preparing the silicon quantum dot-drug molecule composition. According to the method, the silicon quantum dots are connected with drug molecules through short-chain polyethylene glycol molecules, and the prepared silicon quantum dot-drug molecule composition has the advantages of high purity, good water solubility, protein adsorption resistance, no additional fluorescent mark, capability of achieving passive targeting in the body, capability of entering urine through the blood-brain barrier and the glomerular vascular wall to be discharged from the body, a certain drug slow-release effect and the like.

The invention relates to a low-temperature growth method of silicon quantum dots for a solar battery, which belongs to the technical field of silicon quantum dot material. The method comprises the following steps: alternately growing a silicon compound dielectric layer of the stoichiometric proportion and a silicon compound layer containing Si which is several nanometers thick in stoichiometric ratio on a silicon wafer or a quartz sheet or a glass sheet or a stainless steel sheet or high-temperature resistant polymer substrate material at the temperature lower than 450 DEG C by using the plasma chemical vapour deposition (PCVD) technology; carrying out post annealing treatment at the temperature lower than or equal to 550 DEG C by using the rapid photo-thermal annealing technology, so that the residual Si in the silicon compound layer containing Si generates diffusion transfer and solid phase crystallization to form the Si quantum dots, wherein the formed Si quantum dots are arranged in a layered mode, the size of each Si quantum dot is controlled by the thickness of the originally-grown silicon compound layer containing Si, and the density of each Si quantum dot is determined by the content of Si in the original SiN<x> layer containing Si. The invention has the advantages of low depositing temperature, quick speed and good technology controllability and repeatability, thus the uniformity of the grown silicon quantum dot material is good; and the invention is favorable for integrated manufacture and cost reduction of devices.

The invention relates to a silicon quantum dot as well as a preparation method and application thereof and belongs to the field of fluorescent functional nanometer materials. The method comprises the following steps: uniformly mixing a silane coupling agent, a reducing organic acid and deionized water according to a ratio, introducing inert gases for bubbling, and performing microwave-assisted heating, so as to successfully obtain the silicon quantum dot with ultrahigh quantum efficiency, excellent water solubility and excellent fluorescence property. The silicon quantum dot disclosed by the invention can achieve great significance in the field of heavy metal ion detection, particularly in real-time monitoring of Cr (VI) of drinking water and industrial wastewater, and has good application prospects.

The invention relates to the preparation of a typical material, i.e. a quantum dot thin film for a third generation solar cell, and discloses a method for preparing a silicon quantum dot thin film having multiband characteristic. The size distribution of silicon quantum dots is regulated and controlled through the component ratio change of Si/C to further regulate the scope of absorption spectrumof the silicon quantum dots and significantly improve the photoelectric conversion efficiency of the used material. The method further comprises the steps of: at first, performing magnetron co-sputtering on an Si target and a C target by using Ar ions, regulating the sputtering power of the Si/C target, depositing a component-controllable silicon-rich amorphous silicon carbide thin film on silicon and glass matrix; and then, annealing for a few hours at a high temperature under an atmosphere of nitrogen so as to form the silicon quantum dot thin film having certain size distribution, which isembedded inside the amorphous SiC. The thin film has excellent light absorption characteristic within the wavelength range from 1100 nm (infrared light) to 300 nm (ultraviolet light) and is expected to greatly improve the photoelectric conversion efficiency of relevant photovoltaic devices.

Disclosed is a method for making a silicon quantum dot planar concentrating solar cell. At first, silicon nitride or silicon oxide mixed with silicon quantum dots is provided on a transparent substrate. By piling, there is formed a planar optical waveguide for concentrating sunlit into a small dot cast on a small solar cell.

The invention relates to a sequential controllable nanometer silicon quantum dot array resistive random access memory and a preparation method thereof, and belongs to the technical field of non-volatile memories. The resistive random access memory comprises P and a silicon substrate material, and is characterized by also comprising a resistive silicon quantum dot multilayer film nanometer column array attached to the substrate material and an upper electrode and a lower electrode which are attached to the upper surface of the resistive silicon quantum dot multilayer film nanometer column array and the lower surface of the substrate; an insulating medium layer is arranged in the resistive multilayer film nanometer column array; and a silicon quantum dot multilayer film nanometer column is formed by at least two layers of silicon-enriched silicon nitride films which are inlaid with nanometer silicon quantum dots and have different nitrogen components or a silicon-enriched silicon oxide film sublayer which is inlaid with the nanometer silicon quantum dots and has different oxygen components. The sequential controllable nanometer silicon quantum dot array resistive random access memory can be compatible with the current micro-electronic process technology, and can show the advantage of sequential controllable nanometer silicon in resistive random access memory materials to fulfillthe aim of improving the switch ratio and stability of the resistive materials, so that nanometer silicon quantum dots are applied in silica-based nanometer memories in future.

The invention aims at providing a preparation method of nanometer silicon quantum dots and application of the method in the manufacture of film solar batteries. The invention uses a PECVD method for growing amorphous silicon, and adopts double light beams for scanning the crystalline amorphous silicon films layer by layer, i.e. the double-light-beam interference of two beams of femtosecond lasers with the polarization state of round polarization state is used for forming nanometer crystalline silicon in amorphous lattices, and the scanning on the amorphous silicon by the double beams of the femtosecond lasers layer by layer utilizes the movement of a three-dimensional sample table. First, the femtosecond laser is gathered at a point in the sample, and the laser carries out plane scanning on the samples in the depth of the sample in a way of moving scanning line by line. After the scanning of the layer is completed, the sample table is moved up, and the laser is gathered on an upper plane again for scanning. Through regulating and controlling the laser power, the pulse width, the repeating frequency and the scanning speed, nanometer silicon arrays with the size distribution of the crystal grains in a range from 30 to 50 nm and the crystal grain space controlled between 20 and 40 nm are formed in the amorphous silicon lattices, the nanometer silicon quantum dot layer can be used for manufacturing silicon base film batteries, and the battery conversation efficiency can be improved.

The invention discloses a method for improving the efficiency of a solar cell. The method is realized by attaching silicon quantum dots of which the surfaces are modified to the surface of a work area of the solar cell. The method comprises the following steps: modifying the surfaces of the silicon quantum dots; dispersing the silicon quantum dots into a solvent to prepare silicon ink; and printing the silicon ink on the surface of the work area of the solar cell to attach the silicon quantum dots of which the surface are modified to the surface of the work area of the solar cell. The method has the advantages that: a silicon element in a selected raw material has large content in the earth crust, and is easy to obtain and non-toxic. Simultaneously, due to the utilization of the silicon quantum dots, the efficiency of the solar cell is remarkably improved and environment pollution is avoided.

The invention discloses a fluorescent mesoporous silicon oxide nanomaterial and a preparation method and an application thereof. The material is characterized in that a silicon-rich microdomain formed by silicon clusters or silicon quantum dots is embedded in a framework of mesoporous silicon oxide. The preparation method of the material comprises the following steps: adding a water-soluble surfactant and a hydrolyst in water, agitating at 4-60 DEG C and dissolving fully; adding hypoxic silicate ester in the system, continuing agitating for 1-48 h, centrifuging, washing and drying; and calcining in inert atmosphere or vacuum condition to obtain a precursor material. As the fluorescent mesoporous silicon oxide nanomaterial prepared by the preparation method disclosed by the invention has good dispersibility, uniform nanometer size and adjustable aperture and adjustable luminescent performance, the fluorescent mesoporous silicon oxide nanomaterial integrates porous structure and fluorescence function, has double functions of drug loading and conveying and synchronous fluorescence imaging, and has potential application value in synchronous diagnosis and treatment of diseases.

The present invention provides a method for making a light emitting diode (LED) through a silica film growth, an annealing treatment and a surface treatment so that the LED whose spectrum covers the whole red-light zone of a white-light spectrum is obtained with stability, economy, environmental protection and high efficiency.

In a method for making a full-spectrum solar cell, there is provided an ordinary solar cell with an anti-reflection layer. The anti-reflection layer is coated with a film of silicon nitride and/or silicon oxide. The silicon/nitrogen ratio and/or the silicon/oxygen ratio and the temperature are regulated, thus forming a silicon-rich film via doping the anti-reflection layer with silicon from the film of silicon nitride and/or silicon oxide. The precipitation of the silicon in the silicon-rich film is executed based on a mechanism of phase separation, thus forming silicon quantum dots of various sizes in the anti-reflection layer.

The invention belongs to the technical field of preparation methods of nano materials and particularly discloses a method for preparing high-yield fluorescent silicon quantum dots by virtue of a hydrothermal method or a microwave method. According to the method, a silicon source is urea propyl trimethoxy silane or urea propyl triethoxy silane; the raw material cost is low, the raw material source is rich, the operation steps are simple, the yield of the prepared quantum dots is high, and the large-scale production and the environmental protection are easily realized; the prepared quantum dots have excellent optical properties and good biocompatibility, and the particle size distribution is uniform; and the silicon quantum dots can be widely applied to the aspects of optoelectronics, solar energy conversion, biosensors, fluorescence probes and the like.

The invention discloses a preparation method of water-soluble green fluorescent silicon quantum dots. The preparation method comprises the following steps: placing a container with anhydrous ethanol into a constant temperature oil bath pan, adding a silane coupling agent and a reducing agent into the container; stirring for 10-120 min, and cooling a solution obtained after the reaction to room temperature so as to obtain a water-soluble green fluorescent silicon quantum dot crude product. When anhydrous ethanol is used as a reaction solvent, anhydrous ethanol can control slow hydrolysis of a silylating reagent to form silanol molecules, which is more favorable for the synthesis of small particle silicon quantum dots. Meanwhile, anhydrous ethanol can dissolve silanol and silanol is more stably stored in the solution, thus reducing the condensation of silanol. The synthetic method of the silicon quantum dots is simple; quantum yield is high; and the silicon quantum dot has strong specific recognition ability for ascorbic acid, has the minimum detection concentration of 0.04 uM, and is an ideal biological probe for detecting trace markers in biological systems.

The invention relates to a novel silicon quantum dot solar cell which belongs to the field of solar cells and is characterized in that a silicon quantum dot layer is added on a pn junction of a traditional crystalline silicon cell. The structure of the solar cell is as follows: phosphorus oxychloride (or boron tribromide) is diffused on a napped p type (or n type) crystalline silicon substrate, then a silicon dioxide layer containing n type (or p type) silicon quantum dots is prepared, silver positive electrodes are finally respectively added on the front surface and the back surface, and an aluminum back surface field of a silver aluminum back electrode is embedded. The cell has simple structure, strong light absorption capacity and large photo-generated current, and the preparation steps are compatible with the preparation process of the existing crystalline silicon solar cell, thereby providing a good solution way for improving the conversion efficiency of the existing crystalline silicon cell.

The invention discloses a silicon carbide quantum dot and a preparation method thereof. The silicon carbide quantum dot is similar to a ball shape, the granularity of the silicon carbide quantum is normally distributed in the range of 2.5nm to 5.5nm, the excitation wavelength of the silicon carbide quantum dot is 250nm to 400nm, the emission wavelength is 350nm to 450nm, and the fluorescent spectrum peak is 380nm, 400nm and 420nm. The preparation method of the silicon carbide quantum dot comprises the following steps of mixing polymethylsilane and toluene solvent according to a mass ratio of 0.5 to 10: 600, heating the mixture in a high-pressure kettle to 500 DEG C to 600 DEG C through a program, and naturally cooling the mixture after preserving heat for 1h to 5h; and filtering the prepared toluene liquid containing the silicon carbide quantum dot, and freeze-drying or centrifuging the filter liquid at a high speed to obtain the silicon carbide quantum dot. The granularity distribution of the silicon carbide quantum dot is concentrated, the luminescence is strong and stable, and the preparation method is simple, easy and environment-friendly.

The invention discloses a method for preparing a carbon silicon-based thin film material containing silicon quantum dots, and the method comprises the steps: cleaning a monocrystalline silicon substrate through employing the technology of standard RCA cleaning; depositing a non-stoichiometric ratio silicon carbide film on the surface of the monocrystalline silicon substrate through employing the technology of PECVD ( Plasma Enhanced Chemical Vapor Deposition), and forming the silicon quantum dots in the deposition process of the non-stoichiometric ratio silicon carbide film; depositing an amorphous carbon film on the non-stoichiometric ratio silicon carbide film through employing the technology of PECVD ; sequentially carrying out the above steps, and preparing a periodic multi-layer film. The material prepared through the above steps is simple in preparation technology, is small in energy consumption, is large in thin area, is good in uniformity, is small in number of defect modes, and is low in tunneling potential barrier of carriers. The method is good in preparation and application of a silicon quantum dot photoelectric device.

The invention discloses an n-i-p heterojunction solar cell with silicon quantum dot and a preparation method thereof, which are characterized in that: a silicon nitride film layer with silicon quantum dot having diameter of 1-6nm is disposed between an N type monocrystalline silicon substrate and a P type noncrystalline silicon layer; and multiple layers in the solar cell overlapped in turn are Ag/Al grid electrode (7), ZnO, Al transparent conductive film (6), P type noncrystalline silicon layer (5), silicon nitride film layer (4) with silicon quantum dot, N type monocrystalline silicon substrate (3), ZnO, Al transparent conductive film (2), and Al metal film back electrode (1). The solar cell has simple structure, wide spectrum response range, high open-circuit voltage and large photocurrent, and the preparation steps of the solar cell are compatible with the existing technology. A good solution is provided for improving conversion efficiency of the existing silicon based solar cell.

The invention discloses a method for preparing yellow or green silicon quantum dots. The method comprises the following steps: (1) dispersing a silicon source, a first reducing agent and a second reducing agent into ultrapure water; then stirring under the protection of protective gas to obtain a mixed solution; (2) heating the mixed solution obtained by step (1) in a reaction container and reacting to obtain a silicon quantum dot solution; and (3) mixing the silicon quantum dot solution obtained by step (2) and an organic reagent and then centrifuging and drying to obtain solid silicon quantum dots. Based on a synergistic effect of the first reducing agent and the second reducing agent, the yellow or green silicon quantum dots with the high quantum yield are synthesized in one step through a simple water-phase method and the silicon quantum dots with different emission wavelengths can be synthesized through adjusting the temperature of heating reaction; and the quantum yield of the green silicon quantum dots is 38.31 percent and the quantum yield of the yellow silicon quantum dots is 29.36 percent.

The invention belongs to the technical field of manufacturing of nano structures, and particularly relates to a method for manufacturing ultrahigh-density germanium silicon quantum dots based on an obliquely-cut silicon substrate. An obliquely-cut Si (001) single crystal wafer is used as the substrate, chemical cleaning is carried out on the single crystal wafer, the wafer is placed in molecular beam epitaxy equipment for high-temperature impurity removing, firstly a layer of silicon buffer layer grows epitaxially, germanium materials grow finally in a heteroepitaxy mode, and therefore the ultrahigh-density germanium silicon quantum dots are obtained. According to the simple, practical and affordable method, the high-quality ultrahigh-density silicon quantum dots are obtained. According to the method, the problems that when the high-density quantum dot materials are manufactured in the prior art, the process is tedious and the quality is not high are solved, and according to the high-quality and high-density quantum dot material manufactured by the method, the photoelectric conversion efficiency based on a quantum dot device is greatly improved.