Abstract: A solar/thermal radiation cell device comprising at least two parallel metal or semiconductor plates of equal or unequal dimensions separated by an air or an insulated gap and based on an insulator slab for producing electricity from solar energy. Multiple cells are arranged in a stack and connected in series and/or parallel to cascade the electrical energy obtained.

Abstract: A shingle circuit array and a method of assembling the shingle circuit is provided. The array has a shingle circuit with a substrate, an insulation film layer, a metal layer and TPV cells connected to the metal layer in series forming a shingle pattern with terraces. The substrate is of CTE matched material. The metal layer may be copper pads deposited on the terraces. The TPV cells are bonded to the copper pads and may be GaSb cells. Substrate materials include AlSiC or a Cu/Invar/Cu laminate sheet. The AlSiC material may be a microstructure having a continuous Al-metal phase with a discrete SiC particulate phase. The substrate may also be an enameled cast-iron substrate. The shingle circuit array may be provided in a TPV generator.

Abstract: A low-bandgap, double-heterostructure PV device is provided, including in optical alignment a first InP1−yAsy n-layer formed with an n-type dopant, an GaxIn1−xAs absorber layer, the absorber layer having an n-region formed with an n-type dopant and an p-region formed with a p-type dopant to form a single pn-junction, and a second InP1−yAsy p-layer formed with a p-type dopant, wherein the first and second layers are used for passivation and minority carrier confinement of the absorber layers.

Abstract: The use of newly discovered chemical reaction products, created when reactants combine to form products on the surface of a catalyst, to generate electricity, beams of radiation or mechanical motion. The invention also provides methods to convert the products into electricity or motion. The electric generator consists of a catalyst nanocluster, nanolayer or quantum well placed on a substrate consisting of a semiconductor diode, and a semiconductor diode on the surface of the substrate near the catalyst. The device to generate mechanical motion consists of a catalyst nanocluster, nanolayer or quantum well placed on a substrate, and a hydraulic fluid in contact with the non-reaction side of the substrate, with the surfaces of both the catalyst and substrate mechanically formed to enhance the unidirectional forces on the fluid. Both devices use a fuel-oxidizer mixture brought in contact with the catalyst.

Abstract: The present invention is a hydrocarbon fired thermophotovoltaic furnace having a non-fused silica tube. In a preferred embodiment, the furnace has an infrared emitter tube having a top end and a bottom end and a substantially transparent non-fused silica window tube having a closed top end. The window tube is positioned concentrically around the infrared emitter tube, and the infrared emitter tube is in fluid communication with the window tube. The window tube is preferably composed of Lucalox (alumina or Chromolux), magnesia, yterria, titania, spinel, stablized zirconia or yterria alumina garnet. In another preferred embodiment, the furnace has a radiator tube having a top end and a bottom end and an infrared emitter tube having a closed top end. The infrared emitter tube is positioned concentrically around the radiator tube, and the radiator tube is in fluid communication with the infrared emitter tube. Fluid flows from the inner tube to the outer tube.

Abstract: Thermophotovoltaic (TPV) electric power generators have emitters with infrared (IR) outputs matched with usable wavelengths for converter cells. The emitters have durable substrates, optional refractory isolating layers, conductive refractory metal or inter-metallic emitter layers, and refractory metal oxide antireflection layers. SiC substrates have tungsten or TaSi2 emitter layers and 0.14 micron HfO2, ZrO2, Al2O3, Ta2O5 and TiO2 antireflection layers used as IR emitters for GaSb converter cells in TPV generators.

Abstract: The use of newly discovered chemical reaction products, created when reactants combine to form products on the surface of a catalyst, to generate electricity, beams of radiation or mechanical motion. The invention also provides methods to convert the products into electricity or motion. The electric generator consists of a catalyst nanocluster, nanolayer or quantum well placed on a substrate consisting of a semiconductor diode, and a semiconductor diode on the surface of the substrate near the catalyst. The device to generate mechanical motion consists of a catalyst nanocluster, nanolayer or quantum well placed on a substrate, and a hydraulic fluid in contact with the non-reaction side of the substrate, with the surfaces of both the catalyst and substrate mechanically formed to enhance the unidirectional forces on the fluid. Both devices use a fuel-oxidizer mixture brought in contact with the catalyst.

Abstract: A hybrid power assembly includes a thermophotovoltaic (TPV) power conversion module for converting radiant thermal energy into electrical power, and a battery in electrical communication with the TPV power source and rechargeable by electrical power generated by the TPV power source.

Abstract: A microcavity apparatus and systems for maintaining microcavity spacing over a macroscopic area. An application of this invention is a microscale generator. This microscale generator includes a first element for receiving energy; a second element, opposite the first element for transferring energy; at least one panel on either of the first element or the second element, the panel facing the other element; a device for controlling the distance between the at least one panel and the facing element to form a predetermined, sub-micron gap between the panel and the facing element for increasing energy transfer to the element for receiving; and a device, responsive to the energy transfer, for generating electricity.

Abstract: A shingle circuit array and a method of assembling the shingle circuit is provided. The array has a shingle circuit with a substrate, an insulation film layer, a metal layer and TPV cells connected to the metal layer in series forming a shingle pattern with terraces. The substrate is of CTE matched material. The metal layer may be copper pads deposited on the terraces. The TPV cells are bonded to the copper pads and may be GaSb cells. Examples of substrate materials include AlSiC or a Cu/Invar/Cu laminate sheet. The AlSiC material may be a microstructure having a continuous Al-metal phase with a discrete SiC particulate phase. The shingle circuit array may be provided in a TPV generator.

Abstract: The use of newly discovered chemical reaction products, created when reactants combine to form products on the surface of a catalyst, to generate electricity, beams of radiation or mechanical motion. The invention also provides methods to convert the products into electricity or motion. The electric generator consists of a catalyst nanocluster, nanolayer or quantum well placed on a substrate consisting of a semiconductor diode, and a semiconductor diode on the surface of the substrate near the catalyst. The device to generate mechanical motion consists of a catalyst nanocluster, nanolayer or quantum well placed on a substrate, and a hydraulic fluid in contact with the non-reaction side of the substrate, with the surfaces of both the catalyst and substrate mechanically formed to enhance the unidirectional forces on the fluid. Both devices use a fuel-oxidizer mixture brought in contact with the catalyst.

Abstract: The use of newly discovered chemical reaction products, created when reactants combine to form products on the surface of a catalyst, to generate electricity, beams of radiation or mechanical motion. The invention also provides methods to convert the products into electricity or motion. The electric generator consists of a catalyst nanocluster, nanolayer or quantum well placed on a substrate consisting of a semiconductor diode, and a semiconductor diode on the surface of the substrate near the catalyst. The device to generate mechanical motion consists of a catalyst nanocluster, nanolayer or quantum well placed on a substrate, and a hydraulic fluid in contact with the non-reaction side of the substrate, with the surfaces of both the catalyst and substrate mechanically formed to enhance the unidirectional forces on the fluid. Both devices use a fuel-oxidizer mixture brought in contact with the catalyst.

Abstract: A small and light cylindrical thermophotovoltaic generator uses gaseous fuels, a counter flow heat exchanger, regenerator and low bandgap photovoltaic cells. In the fuel injection system, with preheated air from a recuperator, fuel combustion begins immediately when the fuel and air first meet. A hot and compact burn results from complete and rapid fuel and air mixing. A venturi necks down the air flow, and a chemically etched jet shim disk creates over 150 small fuel jet streams. The emitter geometric configuration provides good hot gas energy transfer to the IR emitter. Four alternate emitter configurations accomplish the good heat transfer. One emitter is a composite SiC with integrally formed internal fins which extend into the combustion chamber. The photovoltaic converter assembly has good spectral control, good high rate but lightweight heat removal and high current-carrying capability, while maintaining low parasitic IR absorption.

Abstract: A thermophotovoltaic generator having a solid body located in a combustion chamber of a burner, with the surface of the solid body being excited to a state of radiation by an air-fuel mixture that is supplied by a delivery unit to the burner, where it combusts, and the radiation strikes a photocell, which then generates electrical energy; and having an exhaust pipe discharging the hot combustion gases from the combustion chamber.

Abstract: A burner/emitter/recuperator assembly for providing a high temperature radiant emitting surface, includes an elongated fuel pipe in communication with a fuel source and extending toward the combustion chamber, and adapted to flow fuel from the fuel source to a nozzle end of the fuel pipe proximate the combustion chamber, a primary air pipe disposed around the fuel pipe and in communication with a relatively cool primary air source, a nozzle end of the primary air pipe being substantially coincident with the nozzle end of the fuel pipe, and a recuperator for preheating secondary air disposed around a distal portion of the primary air pipe and in communication with a secondary air source and a swirler downstream of the recuperator.

Abstract: Thermophotovoltaic (TPV) electric power generators have emitters with infrared (IR) outputs matched with usable wavelengths for converter cells. The emitters have durable substrates, optional refractory isolating layers, conductive refractory metal or inter-metallic emitter layers, and refractory metal oxide antireflection layers. SiC substrates have tungsten or TaSi2 emitter layers and 0.14 micron ZrO2 or Al2O3 antireflection layers used as IR emitters for GaSb converter cells in TPV generators.

Abstract: An improved thermophotovoltaic (TPV) n/p/n device is provided. Monolithic Interconnected Modules (MIMS), semiconductor devices converting infrared radiation to electricity, have been developed with improved electrical and optical performance. The structure is an n-type emitter on a p-type base with an n-type lateral conduction layer. The incorporation of a tunnel junction and the reduction in the amount of p-type material used results in negligible parasitic absorption, decreased series resistance, increased voltage and increased active area. The novel use of a tunnel junction results in the potential for a TPV device with efficiency greater than 24%.

Abstract: A thermophotovoltaic cell is provided containing strained or lattice-matched quantum wells that have a bandgap smaller than the bandgap of the InGaAs alloy. The alloy is lattice-matched to the substrate. These narrow bandgap quantum wells provide more efficient conversion of IR emission from a black body or other emitter by converting energy from a wider range of wavelengths than a conventional single junction cell. The thickness of the quantum well region and the individual thickness of the individual quantum wells are chosen to avoid lattice mismatch defects which cause degradation of thick conventional lattice mismatched devices.

Abstract: A thermophotovoltaic cell and diode photodetector having improved open circuit voltage and high internal efficiency includes a semiconductor body having regions of n-type conductivity and p-type conductivity adjacent each other to form a p-n junction therebetween. The p-type region is of a material having a band gap which will absorb black-body radiation and the n-type region is of a material having a wider band gap than that of the p-type region. This forms a heterojunction between the two regions. The region of n-type region has a doping level which is an order of magnitude less than the doping level in the p-type region. This structure forms a cell having a space charge region in the n-type region.

Abstract: The use of newly discovered chemical reaction products, created when reactants combine to form products on the surface of a catalyst, to generate electricity, beams of radiation or mechanical motion. The invention also provides methods to convert the products into electricity or motion. The electric generator consists of a catalyst nanocluster, nanolayer or quantum well placed on a substrate consisting of a semiconductor diode, and a semiconductor diode on the surface of the substrate near the catalyst. The device to generate mechanical motion consists of a catalyst nanocluster, nanolayer or quantum well placed on a substrate, and a hydraulic fluid in contact with the non-reaction side of the substrate, with the surfaces of both the catalyst and substrate mechanically formed to enhance the unidirectional forces on the fluid. Both devices use a fuel-oxidizer mixture brought in contact with the catalyst.

Abstract: Portable, small, and light-weight radiant and/or electrical power generating sources, constructed according to the principles of this invention, comprise an air/fuel delivery device that houses a fuel canister of pressurized hydrocarbon fuel therein. The fuel canister includes a check valve that is selectively activated to release the pressurized hydrocarbon fuel to a pressure regulator and then through a venturi disposed within the delivery device. The delivery device includes an ignitor that is also activated when the fuel is released. A radiant head is attached to the delivery device and includes a luminous mantle in gas flow communication with the venturi and formed from a fibrous rare earth oxide. The head includes a lens and reflector system adjacent the mantle. Alternatively, or in addition to the radiant head, a thermophotovoltaic head can be attached to the delivery system.

Abstract: A three-layer solid infrared emitter having a spectral output matched to low bandgap TPV cells is provided. The three layers include inner and outer layers, and a core layer between the inner and outer layers. The core layer is of solid fiber reinforced undoped refractory oxide material. The inner layer of siC material absorbs radiation from the radiator, the core layer conducts heat from the inner layer to the outer layer. The core layer is a strengthening layer forming a diffuse reflector for stopping a shine-through of long wavelength radiation from the inner layer thereby preserving spectral selectivity in the outer layer. The emitter material may be cobalt doped, nickel doped, or combination of Ni or Co doped refractory oxides with erbia or a thin erbia selective emitter layer.

Abstract: A technique for enhancing the generation of carriers (ex. electrons and/or holes) in semiconductor devices such as photovoltaic cells and the like, receiving radiation from a heated surface, through the use of micron juxtaposition of the surface of the device and the heated surface and with the gap thereinbetween preferably evacuated.

Abstract: Efficient thermophotovoltaic conversion can be performed using photovoltaic devices with a band gap in the 0.75-1.4 electron volt range, and selective infrared emitters chosen from among the rare earth oxides which are thermally stimulated to emit infrared radiation whose energy very largely corresponds to the aforementioned band gap. It is possible to use thermovoltaic devices operating at relatively high temperatures, up to about 300.degree. C., without seriously impairing the efficiency of energy conversion.

Abstract: A thermophotovoltaic electric generating system provides high thermal to electric conversion efficiency by use of a sequence of matched radiation emitters and radiation collectors. The radiation emitters comprises ceramic materials which emit thermally stimulated quantum radiation in at least one characteristic wavelength bands when heated above a threshold temperature. By employing a sequence of selective emitters such as rare earth metal oxide, more than 50% of the radiation emitted from the surface can be concentrated in two or more characteristic wavelength bands. A sequence of corresponding photovoltaic device selectively absorbing and efficiently converting the radiation at the characteristic wavelength bands for high electric conversion efficiency in each zone, respectively. An overlying layer of the photovoltaic collector selectively absorbs at least one of such characteristic wavelength bands.

Abstract: A front-side or back-side illuminated variable current-voltage thermophotovoltaic device comprises a support substrate; isolation layers disposed on the support substrate; a plurality of cells disposed on the isolation layers, each of the cells including a base layer and an emitter layer; an insulating member disposed between each of the cells configured to isolate each cell from adjacent cells; an ohmic contact configured to connect each cell to another cell in series; and a spectral control device disposed on top of the cells and/or on the bottom surface of the support substrate.

Abstract: A TPV cell apparatus with a base region of GaSb crystals. The GaSb crystals are of varying orientations and joined at grain boundaries. A surface region is provided on the GaSb crystals. The GaSb crystals are Tellurium doped N-type GaSb and the surface region is thin Zinc doped P-type GaSb cells. The surface region faces an infrared source. A bus region is connected to a metal grid connected which is in contact with the surface region of the cell. A continuous metal layer is in contact with the GaSb crystals. A multilayer coating is provided on a front side of the cell. The multilayer coating forms an infrared filter for transmitting convertible infrared energy to the cell and for reflecting as much of non-convertible infrared energy back to the IR source as possible. A TPV generator may be provided with the TPV cells.

Abstract: A method and apparatus for the direct conversion of energy by thermovoltaic energy conversion having first and second tubesheets, at least one photon emitter plate secured to and extending from the first tubesheet, at least one cold plate secured to and extending from the second tubesheet, a plurality of thermovoltaic cells disposed along oppositely disposed exterior surfaces of the cold plate, and means cooperating with the tubesheet for maintaining a vacuum between the photon emitter plate and the cold plate.

Abstract: A thermophotovoltaic (TPV) energy conversion semiconductor device is provided which incorporates a heavily doped n-type region and which, as a consequence, has improved TPV conversion efficiency. The thermophotovoltaic energy conversion device includes an emitter layer having first and second opposed sides and a base layer in contact with the first side of the emitter layer. A highly doped n-type cap layer is formed on the second side of the emitter layer or, in another embodiment, a heavily doped n-type emitter layer takes the place of the cap layer.

Abstract: The TPV generator unit insert has air circulation fans that supply air for both TPV cell cooling and heat transfer and room air circulation. Combustion air is supplied by a blower and mixed with natural gas or propane in a mixing chamber. Fuel and air mixing is enhanced by injecting the fuel counter to the air flow in an air supply tube within the mixing chamber. The fuel and air mixture is then injected into a combustion chamber and burned. The hot combustion gases then heat an IR emitter. Infrared radiation from the emitter is then incident on TPV cells, where electricity is produced. The hot by-product gases then transfer heat to the circulating room air in an upper plenum prior to exiting the room through the flue pipe. The yellow-orange glow from the emitter is visible through a front glass window, which then produces a very aesthetically pleasing effect. The rectangular unit is designed to include at least two cell panels at front and at the back.

Abstract: A dot-junction photovoltaic cell using high absorption semi-conductors increases photovoltaic conversion performance of direct band gap semi-conductors by utilizing dot-junction cell geometry. This geometry is applied to highly absorbing materials, including In.sub.x-1 Ga.sub.x As. The photovoltaic cell configured to be separated into a thin active region and a thick, inactive substrate, which serves as a mechanical support.

Abstract: The photo-semiconducting electrode of the present invention comprises a semiconducting substrate, a chemically adsorbed film formed thereon composed of at least one compound selected from the compounds represented by the formulas: formulas (I) R.sup.1 M.sup.1 Y.sub.1.sub.3, (II) R.sup.1 R.sup.2 M.sup.1 Y.sup.1.sub.2, (III) R.sup.1 R.sup.2 R.sup.3 M.sup.1 Y.sup.1 and (IV) R.sup.1 --SH, respectively, and a dye which is fixed to the surface of the chemically adsorbed film and has a functional group capable of reacting with a halogen atom. Because of this, the photo-semiconductor electrode of the present invention is capable of efficiently absorbing solar light and performing energy conversion and superior in photoelectric conversion efficiency, stability and durability. In addition, it can be easily produced.

Abstract: A thermophotovoltaic generator apparatus includes a thermophotovoltaic converter assembly and a cooling fan positioned beneath the assembly for generating an updraft around the assembly. A fuel source is connected to the converter assembly by a fuel line. A new control system, which may include a non-metallic electrode for flame sensing and, regulates flow of fuel from the fuel source to the converter assembly. A housing encloses the cooling fan and the converter assembly. The converter assembly includes a fuel injector cup having a fuel inlet connected to the fuel source and a fuel outlet. A combustion chamber is positioned above the cup for receiving fuel from the fuel outlet and for allowing hydrocarbon combustion. A combustion fan is positioned between the cup and the cooling fan for generating an updraft into the combustion chamber. An infrared emitter is positioned around the combustion chamber for emitting infrared radiation when heated by combustion gases resulting from the hydrocarbon combustion.

Abstract: Solar power is concentrated onto an absorptive surface of a body to heat the body to thus result in infrared emissions. The wavelength spectrum of the infrared emissions is tailored to match the optimal incident wavelength spectrum of photovoltaic cells. This tailoring is accomplished by use of an infrared filter and/or a coating material on an emissions surface of the body. The photovoltaic cells, constructed to match the radiation spectrum of the infrared emissions, convert the infrared emissions to electric energy.

Abstract: A thermally integrated burner/emitter/recuperator (BER) for a thermophotovoltaic (TPV) electric generator achieves improved energy efficiency using either liquid or gaseous fuels. A mixed ceramic and metallic alloy heat exchanger, together with a high temperature emitter, achieves increased energy density in a compact and lightweight assembly.

Abstract: A photovoltaic power conversion device has a top surface adapted to receive impinging radiation. The device includes at least two adjacent, serially connected cells. Each cell includes a semi-insulating substrate and a lateral conductivity layer of a first doped electrical conductivity disposed on the substrate. A base layer is disposed on the lateral conductivity layer and has the same electrical charge conductivity thereof. An emitter layer of a second doped electrical conductivity of opposite electrical charge is disposed on the base layer and forms a p-n junction therebetween. A plurality of spaced channels are formed in the emitter and base layers to expose the lateral conductivity layer at the bottoms thereof. A front contact grid is positioned on the top surface of the emitter layer of each cell. A first current collector is positioned along one outside edge of at least one first cell.

Abstract: The apparatus is a selective radiation emitter to be used in conjunction with a photocell for thermophotovoltaic generation of electricity from heat. One embodiment of the emitter is a layer of selectively radiating rare earth oxide bonded onto a heated base metal layer by the use of an intermediate thin layer of porous metal powder. Another embodiment is an emitter of a thick metal powder layer combined with a rare earth oxide which is formed into the voids in the metal powder structure and bonded to a metal substrate which is to be heated. In this embodiment the metal powder grains are gold plated to limit their emissivity, so that emission outside the desired band of the rare earth oxide is greatly reduced.

Abstract: A thermophotovoltaic generator includes an infrared cobalt oxide doped refractory ceramic emitter having a broad power band region which is matched with the energy conversion band of a low bandgap thermophotovoltaic cell receiver. The generator is provided with a heat source or is constructed for mounting on a heat source or for holding a heat source, such as a radioisotope. The generator is compatible with any heat source, including, but not limited to, a hydrocarbon flame, nuclear reactors, and radioisotopes. The emitter is made of a refractory ceramic material such as cobalt oxide doped alumina or magnesia. The refractory compound of the emitter is preferably doped with a small number of substitutional ions to create a material for emitting near blackbody radiation in a wide wavelength band above a threshold energy level and a minimal amount of radiation at wavelengths longer than the threshold level.

Abstract: A thermophotovoltaic (TPV) system converts thermal or radiant heat into oxygen and electricity for use in a variety of applications. The TPV system and method for efficiently generating-oxygen and electric power through the combustion of fossil fuels with little or no nitrogen oxides or other undesirable combustion by-products. Combustion temperatures are kept at about 1,700.degree. C. or lower while burning a reactant mixture having an air/fuel ratio of greater than about 3:1. Heat from combustion products can be recycled and recuperated without concern for excessive increases in combustion temperature and subsequent combustor/emitter degradation. The generated oxygen may be harvested for commercial use as well as for introduction back into the TPV system.As a by-product of this improved TPV system, we have discovered an inexpensive, environmentally-friendly, and commercially viable method for generating pure oxygen molecules and electricity.

Abstract: A thermophotovoltaic device includes at least one thermal radiator tube, a cooling tube concentrically disposed within each thermal radiator tube and an array of thermophotovoltaic cells disposed on the exterior surface of the cooling tube. A shell having a first end and a second end surrounds the thermal radiator tube. Inner and outer tubesheets, each having an aperture corresponding to each cooling tube, are located at each end of the shell. The thermal radiator tube extends within the shell between the inner tubesheets. The cooling tube extends within the shell through the corresponding apertures of the two inner tubesheets to the corresponding apertures of the two outer tubesheets. A plurality of the thermal radiator tubes can be arranged in a staggered or an in-line configuration within the shell.

Abstract: A thermophotovoltaic energy conversion device and a method for making the device. The device includes a substrate formed from a bulk single crystal material having a bandgap (E.sub.g) of 0.4 eV<E.sub.g <0.7 eV and an emitter fabricated on the substrate formed from one of a p-type or an n-type material. Another thermophotovoltaic energy conversion device includes a host substrate formed from a bulk single crystal material and lattice-matched ternary or quaternary III-V semiconductor active layers.

Abstract: A thermophotovoltaic device and a method for making the thermophotovoltaic device. The device includes an n-type semiconductor material substrate having top and bottom surfaces, a tunnel junction formed on the top surface of the substrate, a region of active layers formed on top of the tunnel junction and a back surface reflector (BSR). The tunnel junction includes a layer of heavily doped n-type semiconductor material that is formed on the top surface of the substrate and a layer of heavily doped p-type semiconductor material formed on the n-type layer. An optional pseudomorphic layer can be formed between the n-type and p-type layers. A region of active layers is formed on top of the tunnel junction. This region includes a base layer of p-type semiconductor material and an emitter layer of n-type semiconductor material. An optional front surface window layer can be formed on top of the emitter layer.

Abstract: A nuclear battery for supplying low level electrical energy for a relatively long period of time. The battery includes a low-energy beta emitter and phosphor dispersed sufficient proximate the beta emitter to capture the low energy betas before decay. A photovoltaic receptor is configured to have a peaked response near the wavelength of the photons emitted by the phosphor. In a preferred embodiment, the photovoltaic, phosphor and beta source are formed into flexible layers which are rolled into a cylinder in order to maximize the capture of photons emitted by the beta-excited phosphor.

Abstract: A filter system to transmit short wavelength radiation and reflect long wavelength radiation for a thermophotovoltaic energy conversion cell comprises an optically transparent substrate segregation layer with at least one coherent wavelength in optical thickness; a dielectric interference filter deposited on one side of the substrate segregation layer, the interference filter being disposed toward the source of radiation, the interference filter including a plurality of alternating layers of high and low optical index materials adapted to change from transmitting to reflecting at a nominal wavelength .lambda..sub.IF approximately equal to the bandgap wavelength .lambda..sub.g of the thermophotovoltaic cell, the interference filter being adapted to transmit incident radiation from about 0.5.lambda..sub.IF to .lambda..sub.IF and reflect from .lambda..sub.IF to about 2.lambda..sub.

Abstract: A method for making rare earth metal oxide ceramic precursor composition comprising reacting a rare earth metal alkoxide with a complexing agent to give a mixture of complexing agent/alkoxide rare earth metal complexes is disclosed. The mixture is hydrolyzed and the precursor composition is isolated. Solubility of the precursor composition in non-polar or polar solvents is affected by the selection of complexing agent amongst other factors. At least partial dissolution of the precursor composition in a solvent gives a preceramic liquid which upon evaporation of the solvent and heating gives a rare earth metal oxide ceramic. Utility of the preceramic liquid include the formation of rare earth metal oxide fibers, thin films, coatings, foams, powders, cast or molded objects or it may be used as a ceramic adhesive.

Abstract: A hydrocarbon fired room heater with thermophotovoltaic electric generator has high power outputs without cell overheating and failure. The unit includes a burner for generating a hydrocarbon flame, a catalytic emitter positioned in the hydrocarbon flame for emitting infrared radiation when heated by the flame, a receiver positioned around the catalytic emitter for receiving the infrared radiation and for converting the infrared radiation to electric power, an exhaust chimney positioned adjacent the receiver, and air draw ducts having uncovered tops, upper parts, and lower parts and positioned adjacent the chimney and the receiver for directing heat up and away from the receiver. The chimney is positioned directly above the top edge of the receiver, and the air draw ducts are positioned adjacent the receiver and chimney for defining air draw channels. Each air draw duct is a generally U-shaped member having a pair of side walls and a boundary wall extending between the side walls.

Abstract: A mantle or emitter used to illuminate a photovoltaic cell. In one embodit, a tubular mantle or emitter is made of a composite structure including a rare-earth material, such as ytterbium oxide, covering a porous ceramic, such as alumina or zirconia, formed on a metal or ceramic support mesh. A hydrocarbon fuel-air mixture is forced into the mantle causing combustion and the rare-earth material to heat up to incandescent temperature, creating a highly radiant selective emitting surface. In another embodiment, a tubular burner-emitter having a mantle surrounded by an inner and outer glass tube permits the preheating of air used for combustion within a toroidal gap formed by the inner and outer glass tubes. In another embodiment, a tubular burner-emitter is used in combination with hinged photovoltaic cells or solar panels so that the photovoltaic cells can be positioned around the burner-emitter so that electromagnetic radiation from the burner-emitter causes the photovoltaic cells to create electrical energy.

Abstract: The invention provides a self-powered device having at least one substrate, at least one radioactive power source formed over the substrate, and integrated circuits formed over the substrate. The radioactive power source includes a first active layer of a first conductivity type, a second active layer of a second conductivity type. The first and second active layers form a depletion layer. A tritium containing layer is provided which supplies beta particles that penetrates the depletion layer generating electron-hole pairs. The electron-hole pairs are swept by the electric field in the depletion layer producing an electric current.

Abstract: A photovoltaic cell used in a direct energy conversion generator for converting heat to electricity includes a reflective layer disposed within the cell between the active layers of the cell and the cell substrate. The reflective layer reflects photons of low energy back to a photon producing emitter for reabsorption by the emitter, or reflects photons with energy greater than the cell bandgap back to the cell active layers for conversion into electricity. The reflective layer can comprise a reflective metal such as gold while the substrate can comprise heavily doped silicon or a metal.

Abstract: A parallel paired, closely coupled, first and second resonant notch filter array. The disclosed frequency doubling filters are particularly useful in the field of thermophotovoltaics for upgrading black body radiation from heated objects to a shorter wavelength such as for illuminating silicon solar cells.