65 results about "Low energy photons" patented technology

A CMOS-compatible FET has a reduced electron affinity polycrystalline or microcrystalline SiC gate that is electrically isolated (floating) or interconnected. The SiC material composition is selected to establish the barrier energy between the SiC gate and a gate insulator. In a memory application, such as a flash EEPROM, the SiC composition is selected to establish a lower barrier energy to reduce write and erase voltages and times or accommodate the particular data charge retention time needed for the particular application. In a light detector or imaging application, the SiC composition is selected to provide sensitivity to the desired wavelength of light. Unlike conventional photodetectors, light is absorbed in the floating gate, thereby ejecting previously stored electrons therefrom. Also unlike conventional photodetectors, the light detector according to the present invention is actually more sensitive to lower energy photons as the semiconductor bandgap is increased.

A detector array for an imaging system may exploit the different sensitivities of array pixels to an incident flux of low energy photons with a wavelength falling near the high end of the range of sensitivity of the semiconductor. The detector array may provide the de-multiplexable spatial information. The detector array may include a two-terminal multi-pixel array of Schottky photodiodes electrically connected in parallel.

The invention discloses a fluorescent material with an ultrahigh quantum yield and an application of the fluorescent material, belongs to the technical field of lighting, and particularly relates to a down-conversion fluorescent material and the application thereof, with an ultrahigh quantum yield, cooperatively absorbed by high-energy photon of lighting clusters composed of three or more Yb3+ions and discretely transmitted by a plurality of low-energy photons. The fluorescent material is composed of inorganic substrate materials and lanthanide-based ytterbium ion Yb3+ions which is doped in the inorganic substrate materials in the form of the clusters, and the molar concentration of the Yb3+ions is calculated to be from 0.01% to 20% on the basis that the sum of the molar concentration of whole metal positive ions is 100%. The number of the Yb3+ions in the clusters is three, four, five or more. The fluorescent material can be applied to improve photoelectric conversion efficiency of solar cells, and reduce ultraviolet irradiation intensity and photovoltaic cell thermalization loss.

The invention discloses an up-conversion solar cell, relating to a solar cell. The up-conversion silicon solar cell is a nano up-conversion luminescence layer (3) prepared with nano up-conversion luminescent materials by the method of carrying out spin coating or screen printing on the back surface of the silicon solar cell (2); sunlight (1) comes in from the front of the silicon solar cell (2). The materials of the nano up-conversion luminescence layer (3) are silicon dioxide-lanthanum fluoride nanocrystalline glass ceramics doped with erbium ions, or silicon dioxide-lanthanum fluoride nanocrystalline glass ceramics doped with both erbium ions and ytterbium ions or zinc sulfide doped with erbium ions. The nano luminescence layer is 0.5-2um thick. The up-conversion silicon solar cell can convert the low-energy photons which can not be effectively absorbed by the silicon solar cells to the high-energy photons which the silicon solar cells can respond to, thus expanding the spectral response range of the solar cells, improving the service efficiency of sunlight in unit area and lowering the cost.

A composite target is provided and is interacted with an electron to generate an X-ray, and an energy of the electron can be changed by controlling a tube voltage at least. The composite target includes a target body and an interposing layer which is connected with the target body. The interposing layer moves a highest peak of an energy spectrum of the X-ray toward a high energy direction. The interposing layer may be a single metal or a metal mixture. Not only a low energy photon of the X-ray can be filtered by the interposing layer, but also a distribution of the low energy photon of the X-ray can be increased by increasing a thickness of the interposing layer. As the tube voltage is enhanced, an amount of a high energy photon of the X-ray generated is dramatically increased. An X-ray tube containing the above composite target is also provided.

Photoelectric systems combining a semiconductor and a phosphorescent compound with an emission spectrum of photons with energy levels equal to or greater than the activation energy of the semiconductor, wherein the phosphorescent compound is characterized by the emission spec-tram being produced by excitation of the phosphorescent compound with lower energy photons and the separation distance between the semiconductor and the phosphorescent compound is less than the distance at or above which scattering losses predominate. Methods are that embody technological applications of the photoelectric systems are also disclosed, as well as articles that embody technological applications of the photoelectric systems.

The present invention generally relates to composition and methods for downconverting light. In some embodiments, the composition and methods comprise an organic material, a nanocrystal, and a ligand capable of facilitating energy transfer between the organic material and the nanocrystal. In certain embodiments, the nanocrystal has a first excited energy state with an energy less than a triplet energy state of the organic material. The organic material, in some embodiments, may be aromatic and/or include one or more pi-conjugated carbon-carbon double bonds. In some cases, incident light may be absorbed by the organic material to produce two triplet excitons. The triplet excitons may then transfer to the nanocrystal via the ligand, where they can undergo recombination, resulting in the formation low energy photons.

A photovoltaic device comprises an upper cell and a lower cell separated by an electrically insulating layer. The cells and the layers are fabricated as a single monolithic structure, and separate electrical contacts are provided for the upper and lower cells to allow independent extraction of current from each cell. The upper cell has a larger bandgap than the lower cell so that incident low energy photons unabsorbed and unconverted by the upper cell can propagate through to the lower cell for conversion. The two bandgaps can be selected to accommodate spectral' ranges of interest. The device is incorporated into a system including two sources of photons with different wavelength ranges associated with the bandgaps of the two cells, such that each cell can convert photons from one source. One source may be the sun and the other may be a local photon source such as a thermal source. Alternatively, both photon sources may be local sources. Operation of the device can be further optimised and extended by configuring the upper cell as a tandem cell or in a MIMS arrangement, or both.

The invention belongs to a low-energy photon brachytherapy system with robot in the medical equipment field. The low-energy photon brachytherapy system comprises an imaging system, a six-degree-of-freedom robot treatment bed, a six-degree-of-freedom surgery robot and a planning software system. The imaging system is a C-arm imaging system or/and a non-X-ray source detector system. The six-degree-of-freedom robot treatment bed is formed by connection of a treatment bed support arm and a bed surface. The six-degree-of-freedom surgery robot consists of a surgical robotic mobile device, a surgical robotic arm, a low-energy photon ray source and a source adapter that are connected successively. According to the low-energy photon brachytherapy system provided by the invention, defects that a dosage cold point exists in existing brachytherapy and the applicability of the therapeutic equipment is low can be overcome. With the brachytherapy system, the treatment dosage design can be optimized; irradiation becomes accurate; dosage cold points are eliminated; the operation becomes simple; and the safety and reliability are high. The low-energy photon brachytherapy system is suitable for clinic treatment of tumors of primary hospitals.

The invention discloses an imaging method used for X-radiography. The imaging method comprises the following steps of: setting a special shape aluminum filter at the central position of a light source of an X-ray machine when an X-ray machine and an X-ray detector are utilized to carry out mammography, absorbing low-energy photons sent by the X-ray machine by the special shape aluminum filter, reducing the quantity scope of received photons on the X-ray detector, and adjusting the X-ray intensity and the regional quantity of different positions of a breast model region, wherein the thickness of the special shape aluminum filter is gradually increased from the center to the external edge. The imaging method can reduce the quantity scope of the received photons on the X-ray detector, adjust the X-ray intensity and the regional quantity, and enhance the imaging quality.

The invention discloses a three-junction cascade solar battery which comprises a Ge battery of a bottom layer, an InGaAs battery of a middle layer and an (Al) GaInP battery of a top layer. In(Ga)As quantum dots are embedded in the InGaAs battery of the middle layer. The invention further discloses a manufacturing method of the three-junction cascade solar battery. The In(Ga)As quantum dots are embedded in the three-junction (Al) GaInP/InGaAs/Ge batteries in traditional lattice matching, adsorption of low-energy photons and separation of carriers are performed by quantum dot materials, the interlayer coupling of the quantum dots is fully utilized, the physical mechanism that the density of the quantum dots influences quantum efficiency and solar battery photoelectric conversion efficiency is utilized to achieve effective combination of a traditional multijunction structure and a novel quantum dot structure, band gap design and regulation of a three-junction battery in photocurrent matching are achieved, adsorption of sunlight low-energy spectra is achieved to the largest extent, and accordingly conversion efficiency of the three-junction cascade solar battery is improved.

In some embodiments, without limitation, the invention comprises a modulated image-guided x-ray brachytherapy system including a source providing low-energy photons, the source configured for placement at least partially within a patient, a control system configured to modulate the source, and an imaging systems for locating the source relative to a treatment location in the patient. The system may further comprises a target at least partially within the patient, a generator located outside the patient for providing low-energy photons, the generator configured to direct low-energy photons to the target, and a conduit between the generator and the target providing a path for the low-energy photons to travel inside the patient. The system may further comprise an in situ x-ray generator for insertion within the patient. The system may further comprise a radioactive pellet.

An extremely non-degenerate two photon absorption (END-2PA) method and apparatus provide for irradiating a semiconductor material substrate simultaneously with two photons each of different energy less than a bandgap energy of the semiconductor material substrate but in an aggregate greater than the bandgap energy of the semiconductor material substrate. A ratio of a higher energy photon energy to a lower energy photon energy is at least about 3.0. Alternatively, or as an adjunct, the higher energy photon has an energy at least about 75% of the bandgap energy and the lower energy photon has an energy no greater than about 25% of the bandgap energy.

The present invention includes upconversion materials such as lanthanide-sensitized oxides that are useful for converting low-energy photons into high-energy photons. Because silicon-based solar cells have an intrinsic optical band-gap of 1.1 eV, low-energy photons having a wavelength longer than 1100 nm, e g., infrared photons, cannot be absorbed by the solar cell and used for photovoltaic energy conversion. Only those photons that have an energy equal to or greater than the solar cell's band gap, e.g., visible photons, can be absorbed and used for photovoltaic energy conversion. The oxides described herein transform photons having an energy less than the energy of a solar cell's band gap into photons having an energy equal to or greater than the energy of the band gap. When these oxides are incorporated into a solar cell, they provide more photons for photovoltaic energy conversion than otherwise would be available in their absence. Nearly 10% of the infrared photons incident on these oxides are upconverted into visible photons. This upconversion efficiency is more than twice as large as the upconversion efficiency for NaYF₄-based upconversion materials. The solar radiation energy conversion efficiency of a silicon-based solar cell will increase by 1.8% or greater by including the oxides described herein because they allow the solar cell to absorb and use are larger portion of the solar spectrum for photovoltaic energy conversion.

The invention discloses a high-light-transmittance photovoltaic packaging material adopting a nucleating antireflection agent. The photovoltaic packaging material is prepared by performing the steps of premixing, melt extrusion, casting film formation, cooling, slitting, winding and the like on photovoltaic packaging material matrix resin, graft modified matrix resin, the nucleating antireflectionagent and other auxiliary agents; by adding the nucleating antireflection agent with quantum dot nanoparticles into a packaging material system, on the one hand, the crystallization behavior of crystallizable polymer chain segments in resin structures is changed, the crystallization rate is accelerated, the crystal density is increased, the micronization of grain size is promoted, and the grain size is smaller than the visible wavelength, thereby improving the transmittance of the photovoltaic packaging material; on the other hand, the quantum dot nanoparticles have the function of convertingshort waves into long waves, can realize the conversion of high-energy photons into a large number of low-energy photons, and have the effect of photon multiplication, so that the intensity of lightincident on a battery piece is increased, the utilization of sunlight by components is enhanced, and the photoelectric conversion efficiency of components is optimized and improved.

The invention belongs to the technical field of coal separation, and particularly relates to a waterless separator of high-sulfur coal and low sulfur coal gangue blocks and sulfur blocks. The waterless separator comprises a raw coal screening graded feed system, an elastic double-flange coal conveyor, a high-sulfur coal gangue block and sulfur block separating system, a low-sulfur conveying electronic weighing scale, a high-sulfur coal gangue block and sulfur block conveying system, an electric variable frequency speed regulating system, a programmable control type electric appliance interlocking device, a photoelectric conversion and electronic pulse filter, a detecting head shielded chamber, a 238 Pu low-energy photon source and a probe. The photoelectric conversion and electronic pulsefilter, the probe and the 238 Pu low-energy photon source form an online recognition separation detecting system of 238 Pu type coal sulfur and ash to waterlessly separate the high-sulfur coal blocks, the gangue blocks and the sulfur blocks in raw coal blocks and obtain low-sulfur low-ash refined coal, and no slime water is generated to pollute the environment, thereby greatly reducing the coal separation energy consumption and the coal separation cost.

The invention relates to a heterojunction solar cell and a preparation method thereof, and belongs to the technical field of solar cell manufacturing. Comprising a crystalline silicon substrate, and a front intrinsic amorphous silicon layer, an N-type doped layer, a front TCO layer and a front metal electrode are sequentially deposited on the front surface of the crystalline silicon substrate; a back intrinsic amorphous silicon layer, a P-type doped layer, a back TCO layer and a back metal electrode are sequentially deposited on the back of the crystalline silicon substrate, and a functional film containing a down-conversion fluorescent material covers a fine gate electrode in the front metal electrode and the front TCO layer which is not shielded by the metal electrode. By introducing the functional film containing the down-conversion fluorescent material, photons in a short-wave region which cannot be utilized by a solar cell can be converted into photon energy matched with spectral response of the photons, namely photons below 400nm are absorbed and converted into low-energy photons of 400-1100nm, so that absorption and utilization of the cell to sunlight are promoted, and the conversion efficiency of the solar cell is improved. The conversion efficiency of the heterojunction solar cell is improved, and the damage effect of part of ultraviolet light on the cell is weakened.

The invention relates to methods and means for improving the power generated, and thus efficiency of solar cells (20, 30). The best mode of the invention at present is considered to be a double or triple junction tandem solar cell (20, 30) that has one or two photon filters (100, 101) of the invention in between the solar cell layers (200, 201, 202, 203), respectively. The photon filter (100, 101, 102) is arranged to reflect photons with wavelength shorter than x and arranged to be transparent to photons of wavelength longer than x by focussing the said lower energy photons out of small area apertures (140, 141) on the other side of the photon filter (100, 101, 102) and arranging the other side of the photon filter (100, 101, 102) to reflect (150, 151) at least some of the said photons of wavelength longer than x.; By using the photon filters (100, 101, and 102) of the invention in between the solar cell layers (200, 201, 202, and 203), photons can be trapped between filters to solar cell layers at an energy at which the quantum efficiency (QE) of the solar cell layer is the best.