Patent Application
20170018675
The present disclosure relates to power conversion devices and devices incorporating the same.
Solar cells, including multi-junction solar cells that have substantially similar bandgaps (in which a top cell receives incident light and a second cell subsequently receives any transmitted light), may be used in laser power conversion. Power converters can also include laser power conversion devices in which sub-cell thickness optimization may be used to achieve current matching conditions.
Two-junction or multi-junction laser power converters, where the first cell is about 500 nm-600 nm thick and the second is between about 600 nm and 3000 nm thick and made from GaAs, InGsAsP, InGaP, InGaAlP, InGaAs, GaSb, or AlGaAs, have also been used. Some converters may also include laser power converters with only two junctions in which the band gaps are not similar, as well as laser power converters that deliver illumination via an optical fiber plus atmosphere.
Embodiments described herein may be applied in a number of overlapping specific fields, including but not limited to laser power conversion, wearable electronic devices, power transfer, implantable electronics, Internet of Things (IoT), and energy harvesting.
According to some embodiments, an optical power converter device includes a light source configured to emit monochromatic light, and a multi-junction photovoltaic cell including respective photovoltaic cell layers having different bandgaps and/or thicknesses. The respective photovoltaic cell layers are electrically connected to collectively provide an output voltage and are vertically stacked relative to a surface of the multi-junction photovoltaic cell that is arranged for illumination by the monochromatic light from the light source. Responsive to the illumination of the surface by the monochromatic light from the light source, the respective photovoltaic cell layers are configured to generate respective output photocurrents that are substantially equal.
In some embodiments, responsive to the illumination of the surface by the monochromatic light from the light source, the respective photovoltaic cell layers may be configured to generate respective excess photocurrents that are unequal.
In some embodiments, one of the respective photovoltaic cell layers may be configured to generate the respective excess photocurrent in response to the illumination of the surface by the monochromatic light and reemit photons therefrom. Another of the respective photovoltaic cell layers may be configured to generate the respective excess photocurrent in response to absorption of the photons reemitted from the one of the respective photovoltaic cell layers that is vertically stacked thereon.
In some embodiments, at least one of the respective photovoltaic cell layers may have a bandgap and/or thickness such that absorption of the monochromatic light is unequal among the photovoltaic cell layers.
In some embodiments, the respective photovoltaic cell layers may be vertically stacked in order of increasing thickness relative to the surface of the multi-junction photovoltaic cell that is arranged for illumination by the monochromatic light. That is, the thickness of each layer may progressively increase from closer to the light source to further therefrom.
In some embodiments, semiconductor materials of the respective photovoltaic cell layers may be selected to have a range of bandgaps suitable for cascaded luminescent coupling. For example, the respective photovoltaic cell layers may be vertically stacked in order of decreasing bandgap relative to the surface of the multi-junction photovoltaic cell that is arranged for illumination by the monochromatic light.
In some embodiments, the respective photovoltaic cell layers may be lattice matched with respect to one another and/or with respect to a common substrate.
In some embodiments, one of the photovoltaic cell layers that is vertically stacked closer to the surface may be configured to absorb greater than about 90% of a photon energy of the monochromatic light responsive to the illumination of the surface thereby.
In some embodiments, a sum of the different bandgaps of the respective photovoltaic cell layers may exceed a photon energy of the monochromatic light by more than one half electron volt multiplied by a quantity of respective p-n junctions of the stack.
In some embodiments, the respective photovoltaic cell layers may have respective thicknesses within about 10% of one another, and/or two or more of the respective photovoltaic cell layers may have a same bandgap.
In some embodiments, the output voltage may be greater than respective voltages output from the respective photovoltaic cell layers responsive to the illumination. The output voltage may correspond to a charging voltage for a battery of a portable consumer electronics device. The output voltage may be greater than a photon energy of the monochromatic light.
In some embodiments, one of the photovoltaic cells that is vertically stacked closer to the surface may be configured to absorb greater than 1/n of a photon energy of the monochromatic light responsive to the illumination of the surface thereby, where n is the number of photovoltaic cell layers in the multi-junction photovoltaic cell.
In some embodiments, the light source may be a laser light source. The monochromatic light may have a wavelength corresponding to a wavelength range over which the one of the photovoltaic cell layers that is closer to the surface has a maximum quantum efficiency.
In some embodiments, the multi-junction photovoltaic cell and the light source may be assembled on opposite surfaces of a substrate, where the substrate is transparent to a wavelength of the monochromatic light. For example, the substrate may be a lateral conduction layer (LCL) that is configured to extract the respective output photocurrents. The lateral conduction layer may be further transparent to wavelengths of photons reemitted from one or more of the photovoltaic cell layers responsive to the illumination of the surface.
In some embodiments, the multi-junction photovoltaic cell and the light source may be assembled on a high thermal conductivity substrate comprising silicon carbide, silicon, diamond, sapphire, or aluminum nitride.
In some embodiments, the respective photovoltaic cell layers of the multi-junction photovoltaic cell may include one or more transfer-printed photovoltaic cells having respective surface areas of about 4 square millimeters or less.
In some embodiments, the multi-junction photovoltaic cell may be assembled on a substrate that is reflective to a wavelength of the monochromatic light and/or photons reemitted responsive to illumination of the surface thereby. The multi-junction photovoltaic cell may be positioned between the reflective substrate and the light source.
In some embodiments, two or more of the respective photovoltaic cell layers may not be lattice matched to one another.
In some embodiments, the device may further include at least one additional photovoltaic cell layer configured to generate an output current that is substantially equal to the respective output photocurrents of the respective photovoltaic cell layers responsive to illumination thereof by indoor light within a visible wavelength range.
According to further embodiments, a multi-junction photovoltaic cell includes a laser light source configured to emit coherent monochromatic light, and a multi-layer stack comprising respective photovoltaic cell layers that are electrically connected to provide an output voltage The respective photovoltaic cell layers have different bandgaps and/or thicknesses and are vertically stacked relative to a surface of the multi-layer stack that is arranged to for illumination by the coherent monochromatic light. A first one of the respective photovoltaic cell layers that is closer to the laser light source is configured to generate a first output photocurrent and an excess photocurrent such that photons are reemitted therefrom responsive to the illumination of the surface by the coherent monochromatic light. A second one of the respective photovoltaic cell layers that is farther from the laser light source is configured to generate a second output photocurrent responsive to absorption of the photons reemitted from the first one of the respective photovoltaic cell layers. Absorption of the coherent monochromatic light is unequal among the first and second ones of the photovoltaic cell layers, but the first and second output photocurrents are substantially equal.
Other devices, apparatus, and/or methods according to some embodiments will become apparent to one with skill in the art upon review of the following drawings and detailed description. It is intended that all such additional embodiments, in addition to any and all combinations of the above embodiments, be included within this description, be within the scope of the invention, and be protected by the accompanying claims.
Embodiments of the present disclosure provide power converters that may provide higher voltage outputs than possible with traditional single junction power conversion devices. Embodiments of the present disclosure may further employ semiconductor material stacks that are not specifically designed for laser power conversion. Other related advantages according to embodiments of the present disclosure may include the ability to amortize production costs for multi-junction materials across a wider range of devices beyond power converters.
Embodiments of the present disclosure may also achieve less costly and higher voltage output converters that can be more efficiently manufactured, and may allow for the use of less stringent tolerances with respect to the layer thicknesses and/or material bandgaps used in the converters.
Higher voltage output converters according to embodiments of the present disclosure may also use a wider range of light sources with higher efficiency, in addition to monochromatic laser illumination, so as to accommodate wider band illumination from LEDs and other sources.
Higher output voltage converters according to embodiments of the present disclosure may further provide the capability of dual high efficiency conversion, by being able to convert both laser illumination and solar illumination in the same converter. In addition, higher voltage output converters according to embodiments of the present disclosure may also make use of photon recycling to achieve higher current generation.
In the power conversion system 100 of
The materials of the multi-junction cell 215a of
In some embodiments, the multi-junction cell 215a of
The materials of the multi-junction cell 215b of
Thus, in some embodiments of the present disclosure, a multi-junction laser power converter includes a stack of n junctions (where n is an integer greater than 1), and each of the n junctions are defined by materials having different bandgaps from one another. The topmost junction in the stack (which is positioned nearest to the incident illumination) has the highest bandgap, and each junction below in the stack has a progressively smaller bandgap. Thus, the top junction absorbs substantially more than 1/n of the incident light, while the next junction therebelow absorbs substantially more than 1/(n−1) of the remaining incident light, and similarly for the lower junctions.
According to embodiments of the present disclosure, each cell below the top cell is supplied with additional illumination that has been reemitted from previous cells thereabove in the stack, producing a photon recycling effect. Photon recycling thus distributes or otherwise results in current generation that is substantially similar among the respective cells, in a way that may not be otherwise realized for stacks including junctions having non-equal bandgaps.
The above process of electron-hole pair recombination and emission of a photon that is reabsorbed by another layer is the process of photon recycling, which may contribute to several advantages provided by embodiments of the invention. The multiplicity of horizontal arrows in the bottom cell 323 compared to the top cell 321 indicates the greater number of pathways by which current can be generated in the lower cells despite the initial absorption of a laser wavelength in the earlier higher bandgap cells. The effect is to increase the current generated by lower-bandgap cells 322, 323 that would not otherwise absorb as high a fraction of the incident light as the top cell 321, by allowing incident photons another chance to be collected by being absorbed in lower-bandgap cells 322, 323. This is a process by which photon recycling enables embodiments of the invention to use materials of non-equal bandgaps that may not be perfectly matched to the illumination wavelength, such that the absorption of the incident light ay into each layer 321, 322, 323 is not equal for all layers 321, 322, 323. As such, multi-junction power converters in accordance with embodiments of the present disclosure may be used with light sources having a wide range of illumination wavelengths, allowing for greater flexibility in the design and use of such devices in a variety of environments.
In some embodiments of the invention, the monochromatic light source is a laser, such as a laser with a wavelength near 660 nm 205′ as shown in
In some embodiments of the invention, the multi-junction cell may be prepared by dicing the substrate wafer upon which the cell was grown, instead of using micro transfer printing.
In some embodiments the bottom junction may be a germanium cell with a bandgap of 0.7 eV. In further embodiments the bottom cell may be SiGe. In still further embodiments, the bottom cell may be InGaAs. In yet further embodiments, the top and middle cells may be AlGaAs and InGaAIP, respectively. In some embodiments, the light source may be an LED.
The materials of the multi-junction cell 415 of
Thus, in further embodiments, a multi-junction laser power converter includes n junctions (where n is an integer greater than 1), and each of the n junctions are defined by semiconductor materials or compounds having the same or similar bandgaps. Despite unequal absorption of incident light among the cells (for example, where the cell bandgaps are not perfectly matched to the illumination wavelength), the outer cells are supplied with additional illumination that has been reemitted from inner cells in the stack, producing a photon recycling effect. Photon recycling thus distributes or otherwise results in current generation that is substantially similar among the respective cells. As such, multi-junction power converters in accordance with embodiments of the present disclosure may be used with light sources having a wide range of illumination wavelengths, allowing for greater flexibility in the design and use of such devices in a variety of environments.
Although described above primarily with respect to 3-junction cells with reference to particular materials, it will be understood that embodiments of the present disclosure are not so limited. As such, in multi-junction photovoltaic cells in accordance with embodiments of the present disclosure, there may be fewer or more than 3 junctions, using any combinations of the materials mentioned above, or other materials. Also, in some embodiments the cells may be silicon, copper indium gallium selenide (CIGS), or cadmium telluride (CdTe). In other words, the above embodiments are examples of the multiple possible embodiments of the invention and are not intended to be limitations. Other materials and configurations can be used within the scope and spirit of the invention and photon recycling.
Further embodiments of the present disclosure provide devices for efficiently receiving and converting light (for example light from a laser, light emitting diode (LED), incandescent, or fluorescent light source) into electrical energy. Some embodiments provide a miniaturized device by which an active system can receive power, wherein the device is smaller than typical practical alternatives.
In particular, some embodiments of the present disclosure provide device structures that convert monochromatic light into electrical power at standardized or typically-used voltages, e.g. the voltage required to charge batteries including Li-ion batteries, etc. and/or other storage devices including super capacitors, etc. Further embodiments provide device structures that convert monochromatic light into electrical power at voltages that are higher than voltages that are achievable by practical implementations of some conventional laser power converters. Still further embodiments provide device structures that convert indoor light into electrical power at standardized or typically-used voltages, e.g. the voltage required to charge batteries including Li-ion batteries, etc. and/or other storage devices including super capacitors, etc.
In some embodiments of the present disclosure, more than one p-n junction may be formed from or defined by direct band gap semiconductors (for example gallium arsenide, indium phosphide, aluminum gallium arsenide, indium gallium arsenide, indium gallium arsenide phosphide, indium aluminum arsenide, indium gallium arsenide nitride, indium gallium arsenide nitride, and/or their alloys), which are assembled in an electrically connected stack, and having a first p-n junction that is positioned or arranged in the stack to be illuminated by light from an external light source having a first photon energy.
In some embodiments, the stack of p-n junctions may have selected bandgaps such that their summed bandgaps exceeds the photon energy of the external light source by more than one half electron volt multiplied by the number of p-n junctions of the stack.
In some embodiments, the stack of p-n junctions may have different selected bandgaps, thicknesses, and/or absorption characteristics such that the first p-n junction absorbs a fraction of the photon energy of the light incident thereon greater than the fraction one divided by the number of p-n junctions (that is, >1/n, where n is the number of p-n junctions).
In some embodiments, the p-n junctions of the stack may exhibit luminescent coupling, in which some p-n junctions are capable or otherwise configured (under the conditions of illumination) to generate excess photocurrent relative to other p-n junctions, and the excess photocurrent is at least partially converted into light, where one or more of the other p-n junctions are configured to absorb the light generated from the excess photocurrent (and where some of the one or more of the other p-n junctions may not generate excess photocurrent).
Some embodiments of the present disclosure are directed to structures and designs for laser light conversion that can be more practically implementable than some conventional converters (which may require precise balancing of the absorptive characteristics of each p-n junction of the stack for efficient operation). The luminescent coupling of embodiments described herein may allow auto-correction of the photocurrents of the individual p-n junctions of the device, such that the photocurrents generated by each p-n junction of the stack are substantially equal, thereby improving efficiency. Embodiments of the present disclosure can also allow for less stringent manufacturing tolerances of the p-n junctions by a factor of two or more.
The wavelength of the laser light source 505 and the characteristics (e.g., materials and/or thicknesses) of the various photovoltaic cell layers 521, 522, 523, . . . 52n (also referred to herein as “cells” or “sub cells”) are selected to correspond to one another such that the net photocurrent generated in each cell layer in response to the light incident thereon is matched or substantially equal, even if there is unequal absorption of the monochromatic light among the photovoltaic cell layers 521, 522, 523, . . . 52n in some embodiments. For example, the photovoltaic cell layers 521, 522, 523, . . . 52n may be formed from respective semiconductor materials having different bandgaps and/or thicknesses that are not perfectly matched to the illumination wavelength of the incident light 501, such that some cell layers are supplied with additional illumination that has been reemitted from other cell layers in the stack, producing a photon recycling or luminous coupling effect.
In the example of
Still referring to
The p-n junction 530 of the third semiconductor layer 523 likewise converts a portion of the reemitted light 503 into net photocurrent 1I for output, and generates a third amount of excess photocurrent that is converted by photon emission into reemitted light 504 (illustrated as 1i unit). The reemitted light 504 output from the third semiconductor layer 523 due to luminescent coupling thus has a photon energy that is lower than that of the reemitted light 503 output from the second semiconductor layer 522, and is similarly transmitted to the nth semiconductor layer 52n positioned therebelow in the stack 515, whose p-n junction in turn converts the reemitted light 504 into photocurrent 1I for output. As such, each of the photovoltaic cell layers 521, 522, 523, . . . 52n of the stack 515 outputs a substantially equal photocurrent (within a factor of two, for example) due to luminescent coupling between adjacent ones of the layers 521, 522, 523, . . . 52n, despite unequal generation of excess photocurrent and/or absorption among the layers 521, 522, 523, . . . 52n with respect to the wavelengths of the incident light 505.
The net photocurrents 1I may be equalized, for example, based on selection of layer material/bandgap and/or layer thickness, as well as selection of the wavelength of the incident light 501 emitted from the laser light source 505. For example, the second semiconductor layer 522 may be formed of a semiconductor material having a lower bandgap and/or greater thickness than that of the first semiconductor layer 521, the third semiconductor layer 523 may be formed of a semiconductor material having a lower bandgap and/or greater thickness than that of the second semiconductor layer 522, and the nth semiconductor layer 52n may be formed of a semiconductor material having a lower bandgap and/or greater thickness than that of the third semiconductor layer 523. The materials of the multi-junction cell 515 of
In some embodiments, the net photocurrent generated by each cell layer of the stack may include a first current component representing the current generated in response to portions of the incident light that are transmitted thereto (illustrated by vertical arrows in
In
Still referring to
The various stacks of p-n junctions that define the multi-junction photovoltaic cells described herein may be formed using methods of micro-transfer printing. As such, the photovoltaic cell layers of the stacks may each have a respective surface area of less than about 4 square millimeters or less. In some embodiments, the stack of p-n junctions can be formed by transfer printing one or more photovoltaic cell layers into optical contact with one or more other photovoltaic cell layers. Also, the stack of p-n junctions may include one or more photovoltaic layers comprising materials that are not lattice matched to one another.
The layers 521, 522, 523, . . . 52n are thus arranged to form a cascade of luminescent coupling, in which the p-n junctions 530 of the stack 515 are arranged in order of highest bandgap to lowest bandgap relative to the monochromatic light source 805, wherein incident light 801 impinges upon a p-n junction 530 of the first semiconductor layer 521 having a first bandgap (illustrated by way of example as 1.6 eV), and reemitted light from the p-n junction 530 of the first semiconductor layer 521 is absorbed by a p-n junction 530 of the second semiconductor layer 522, which has a second bandgap (illustrated by way of example as 1.5 eV) that is lower than the first bandgap. The p-n junction 530 of the second semiconductor layer 522 generates a second amount of reemitted light that has a photon energy corresponding to the second bandgap of the second semiconductor layer 522, which is lower than the photon energy of the first amount of reemitted light. A p-n junction 530 of the third semiconductor layer 523, having a third bandgap (illustrated by way of example as 1.4 eV) that is lower than the second bandgap of the second semiconductor layer 522, absorbs at least a portion of the second amount of reemitted light, and so forth, until all p-n junctions 530 of the layers 521, 522, 523, . . . 52n have an acceptably-matched (within a factor of two, for example) output photocurrent.
In the example of
In some embodiments, some or all of the photovoltaic cell layers 521, 522, 523, . . . 52n defining the p-n junctions 530 of the stack 515 may have substantially the same thickness (e.g., thicknesses within 10% of one another, for example, within about one micron).
In some embodiments, some or all of the photovoltaic cell layers 521, 522, 523, . . . 52n defining the p-n junctions 530 of the stack 515 have different thicknesses (e.g., the thicknesses of each layer may progressively increase from closer to the incident light source to further therefrom). For example, the thickness of one or more layers may be selected in order to match the excess photocurrent generated by the layer thereabove.
In some embodiments, a reflector (e.g., a mirror) may be formed or otherwise provided in optical contact with the stack 515, opposite the monochromatic light source that provides the incident light.
Although generally described herein with reference to multi-junction photovoltaic cells including photovoltaic cell layers defined by semiconductor materials of different bandgaps, in some embodiments, two or more photovoltaic cell layers of the stack may be formed of semiconductor materials having the same bandgap. Also, although generally illustrated herein with reference to multi-junction photovoltaic cells having four photovoltaic cell layers in each stack, fewer or more layers may be provided in accordance with embodiments of the present disclosure. For example, in some embodiments, the stack of photovoltaic cell layers may include four or more p-n junctions. In some embodiments, the stack of photovoltaic cell layers may include eight or more p-n junctions. Moreover, although described primarily herein with reference to p-n junctions, embodiments of the present disclosure may be implemented by photovoltaic cells formed from semiconductor junctions other than p-n junctions, for example, p-i-n junctions, Schottky junctions, etc. In other words, embodiments of the present disclosure are described with reference to specific types of photovoltaic cells by way of example, but other types of photovoltaic cells may be used in accordance with the embodiments described herein.
The present disclosure has been described above with reference to the accompanying drawings, in which embodiments are shown. However, this invention should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of embodiments of the present disclosure to those skilled in the art. In the drawings, the thickness of layers and regions are exaggerated for clarity. Like numbers refer to like elements throughout.
It will be understood that when an element such as a layer, region or substrate is referred to as being “on” or extending “onto” another element, it can be directly on or extend directly onto the other element or intervening elements may also be present. In contrast, when an element is referred to as being “directly on” or extending “directly onto” another element, there are no intervening elements present. It will also be understood that when an element is referred to as being “connected” or “coupled” to another element, it can be directly connected or coupled to the other element or intervening elements may be present. In contrast, when an element is referred to as being “directly connected” or “directly coupled” to another element, there are no intervening elements present. In no event, however, should “on” or “directly on” be construed as requiring a layer to cover an underlying layer.
It will also be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of embodiments of the present disclosure.
Furthermore, relative terms, such as “lower” or “bottom” and “upper” or “top,” may be used herein to describe one element's relationship to another element as illustrated in the Figures. It will be understood that relative terms are intended to encompass different orientations of the device in addition to the orientation depicted in the Figures. For example, if the device in one of the figures is turned over, elements described as being on the “lower” side of other elements would then be oriented on “upper” sides of the other elements. The exemplary term “lower”, can therefore, encompasses both an orientation of “lower” and “upper,” depending of the particular orientation of the figure. Similarly, if the device in one of the figures is turned over, elements described as “below” or “beneath” other elements would then be oriented “above” the other elements. The exemplary terms “below” or “beneath” can, therefore, encompass both an orientation of above and below.
The terminology used in the description herein is for the purpose of describing particular embodiments only and is not intended to be limiting of embodiments of the present disclosure. As used in the description and the appended claims, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that the term “and/or” as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
Embodiments are described herein with reference to cross-section illustrations that are schematic illustrations of idealized embodiments (and intermediate structures). As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, the regions illustrated in the figures are schematic in nature and their shapes are not intended to illustrate the actual shape of a region of a device and are not intended to limit the scope of embodiments of the present disclosure.
Unless otherwise defined, all terms used in disclosing embodiments, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, and are not necessarily limited to the specific definitions known at the time of the present disclosure. Accordingly, these terms can include equivalent terms that are created after such time. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the present specification and in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entireties.
Aspects of the present disclosure are described herein with reference to flowchart illustrations and/or block diagrams of methods and systems according to embodiments. It is to be understood that the functions/acts noted in the blocks may occur out of the order noted in the operational illustrations. For example, two blocks shown in succession may in fact be executed substantially concurrently or the blocks may sometimes be executed in the reverse order, depending upon the functionality/acts involved.
Many different embodiments have been disclosed herein, in connection with the above description and the drawings. It will be understood that it would be unduly repetitious and obfuscating to literally describe and illustrate every combination and subcombination of these embodiments. Accordingly, the present specification, including the drawings, shall be construed to constitute a complete written description of all combinations and subcombinations of the embodiments described herein, and of the manner and process of making and using them, and shall support claims to any such combination or subcombination.
Although described herein with reference to various embodiments, it will be appreciated that further variations and modifications may be made within the scope and spirit of the principles of the present disclosure. Although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation, the scope of the present disclosure being set forth in the following claims.
This application is a continuation-in-part of U.S. patent application Ser. No. 14/683,498, entitled “MULTI-JUNCTION POWER CONVERTER WITH PHOTON RECYCLING” and filed Apr. 10, 2015, in the United States Patent and Trademark Office, which claims priority from U.S. Provisional Patent Application No. 61/978,569 entitled “MULTI-JUNCTION LASER POWER CONVERTER WITH PHOTON RECYCLING” filed on Apr. 11, 2014, the disclosures of which are incorporated by reference herein in their entireties. This application also claims priority from U.S. Provisional Patent Application No. 62/234,305 entitled “MULTI-JUNCTION PHOTOVOLTAIC MICRO-CELL ARCHITECTURES FOR ENERGY HARVESTING AND/OR LASER POWER CONVERSION” and filed Sep. 29, 2015, in the United States Patent and Trademark Office, the disclosure of which is incorporated by reference herein in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 62234305 | Sep 2015 | US | |
| 61978569 | Apr 2014 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 14683498 | Apr 2015 | US |
| Child | 15280484 | US |
