METHOD AND APPARATUS FOR A THERMOPHOTOVOLTAIC CELL

Abstract

The present device is a thermophotovoltaic (TPV) cell adapted to charge the battery of an electronic device efficiently and cost-effectively. This is accomplished by specifically layering N-Type and P-type semiconductors in several layers while also introducing extrinsic doping agents that add to the conductivity of the oxides used for generating energy using ambient thermal energy. As such, electrical energy can effectively be drawn from a single heat reservoir.

Claims

1. A thermophotovoltaic cell, comprising: a PN junction; a passivation layer; and a pair of opposing conductive current collectors; wherein said PN junction and said passivation layer are positioned between said pair of opposing conductive current collectors.

2. The thermophotovoltaic cell of claim 1, wherein said PN junction further comprises a p-type semiconductor layer and an n-type semiconductor layer.

3. The thermophotovoltaic cell of claim 2, wherein said p-type semiconductor layer further comprises chromium oxide.

4. The thermophotovoltaic cell of claim 2, wherein said n-type semiconductor layer further comprises zinc oxide.

5. The thermophotovoltaic cell of claim 1, wherein said pair of opposing conductive current collectors further comprise an anode and a cathode.

6. The thermophotovoltaic cell of claim 5, wherein said anode further comprises magnesium, aluminum magnesium alloy, carbon, graphene, carbon nanotubes, gold, or silver adapted to operate as the negative terminal.

7. The thermophotovoltaic cell of claim 5, wherein said cathode further comprises aluminum, aluminum oxide, carbon, graphene, carbon nanotubes, gold, silver, or copper adapted to operate as the positive terminal.

8. The thermophotovoltaic cell of claim 8, wherein said passivation layer further comprises an insulation tunnel junction comprising aluminum oxide having a junction depth of 10 nm.

9. The thermophotovoltaic cell of claim 5, further comprising five layers, with the first layer being the cathode, the second layer being the passivation layer, the third and fourth layers being the PN junction, and the fifth layer being the anode.

10. A thermophotovoltaic cell, comprising: a PN junction; and a pair of opposing conductive current collectors; wherein said PN junction and said passivation layer are positioned between said pair of opposing conductive current collectors.

11. The thermophotovoltaic cell of claim 10, wherein said PN junction further comprises a p-type semiconductor layer and an n-type semiconductor layer.

12. The thermophotovoltaic cell of claim 11, wherein said p-type semiconductor layer further comprises chromium oxide and wherein said n-type semiconductor layer further comprises zinc oxide.

13. The thermophotovoltaic cell of claim 10, wherein said pair of opposing conductive current collectors further comprise an anode and a cathode.

14. The thermophotovoltaic cell of claim 13, wherein said anode further comprises magnesium, aluminum magnesium alloy, carbon, graphene, carbon nanotubes, gold, or silver adapted to operate as the negative terminal and wherein said cathode further comprises aluminum, aluminum oxide, carbon, graphene, carbon nanotubes, gold, silver, or copper adapted to operate as the positive terminal.

15. The thermophotovoltaic cell of claim 8, further comprising a passivation layer, wherein said passivation layer further comprises an insulation tunnel junction comprising aluminum oxide.

16. The thermophotovoltaic cell of claim 13, further comprising four layers, with the first layer being the cathode, the second and third layers being the PN junction, and the fourth layer being the anode.

17. The method of manufacturing a thermophotovoltaic cell, the method comprising: placing a first substrate into a chamber; forming a passivation layer on said first substrate; forming a PN junction on said passivation layer; forming a second substrate on said PN junction; and annealing said first substrate, passivation layer, PN junction, and second substrate in a vacuum chamber filled with an inert gas; wherein said first substrate, passivation layer, PN junction, and second substrate form said thermophotovoltaic cell;

18. The method of claim 17, wherein said passivation layer, PN junction, and second substrate are formed through chemical vapor deposition for thin-film, solid-crystalline layers and wherein thermophotovoltaic cell is annealed after chemical vapor deposition.

19. The method of claim 17, wherein said passivation layer, PN junction, and second substrate are formed through spin coating for thin, amorphous layers.

20. The method of claim 17, wherein said first substrate is a cathode and second substrate is an anode, wherein said cathode further comprises aluminum, aluminum oxide, carbon, graphene, carbon nanotubes, gold, silver, or copper adapted to operate as the positive terminal, wherein said anode further comprises magnesium, aluminum magnesium alloy, carbon, graphene, carbon nanotubes, gold, or silver adapted to operate as the negative terminal, wherein said passivation layer further comprises an insulation tunnel junction comprising aluminum oxide, and wherein said PN junction further comprises p-type semiconductor layer and an n-type semiconductor layer, wherein said p-type semiconductor layer further comprises chromium oxide and wherein said n-type semiconductor layer further comprises zinc oxide.

Description

DESCRIPTION OF THE DRAWINGS

[0018] FIG. 1 is a diagram illustrating a five layer cell structure of the present invention;

[0019] FIG. 2 is a diagram illustrating a single mirrored TPV cell structure of the present invention;

[0020] FIG. 3 is a diagram illustrating valence and conduction bands closest to the fermi level of a plurality of materials;

[0021] FIG. 4 is a diagram illustrating fermi levels of N-Type and P-Type junctions; and

[0022] FIG. 5 is a diagram illustrating the method of manufacturing the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0023] Illustrative embodiments of the invention are described below. The following explanation provides specific details for a thorough understanding of and enabling description for these embodiments. One skilled in the art will understand that the invention may be practiced without such details. In other instances, well-known structures and functions have not been shown or described in detail to avoid unnecessarily obscuring the description of the embodiments.

[0024] Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise,” “comprising,” and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to.” Words using the singular or plural number also include the plural or singular number respectively. Additionally, the words “herein,” “above,” “below” and words of similar import, when used in this application, shall refer to this application as a whole and not to any particular portions of this application. When the claims use the word “or” in reference to a list of two or more items, that word covers all of the following interpretations of the word: any of the items in the list, all of the items in the list and any combination of the items in the list. When the word “each” is used to refer to an element that was previously introduced as being at least one in number, the word “each” does not necessarily imply a plurality of the elements, but can also mean a singular element.

[0025] Embodiments of the present invention are described herein in the context of a thermophotovoltaic cell 10 adapted to charge the battery of an electronic device efficiently and cost-effectively. Those of ordinary skill in the art will realize that the following detailed description of the present invention is illustrative only and is not intended to be in any way limiting. Other embodiments of the present invention will readily suggest themselves to such skilled persons having the benefit of this disclosure. Reference will now be made in detail to implementations of the present invention as illustrated in the accompanying drawings. The same reference indicators will be used throughout the drawings and the following detailed description to refer to the same or like parts.

[0026] The present invention discloses a thermophotovoltaic (TPV) cell 10 comprises a PN junction 20, passivation layer 30, and two conductive current collectors 40, 50 and is adapted to charge the battery of an electronic device efficiently and cost-effectively. This is accomplished by specifically layering N-Type and P-type semiconductors 21, 22 in a particular order, although forward bias, reverse bias, and heterostructures have all been observed to induce electrical generation. Heterojunction integration of the oxide layers seems to contribute the highest performance. As such, the energy in the form of all types of thermal energy transfer (heat) can be captured and converted to useable electrical power without the need for a temperature gradient and with minimal surface area exposure.

[0027] In the preferred embodiment, the present invention comprises of five layers for creating a voltage bias to create a direction for current to flow (see FIG. 1). This current is thermal kinetic energy that generally travels in unpredictable degrees of freedom, but with the voltage bias, and the metal oxides used, the random motion of the atoms can be directed in the same direction at the same time to excite charge carriers therefore creating electricity.

[0028] The first layer 40 is a conductive back surface field (BSF) or foil. The first layer 40 is adapted to serve as the positive terminal (cathode) and aid in current collection. In the preferred embodiment, the first layer 40 comprises Aluminum for its oxide-forming properties. The thickness of the cathode 40 ranges between 100-1000 micrometers.

[0029] The second layer is the passivation layer 30. The passivation layer 30 serves as a tunnel junction, allowing electrons to take on a wave form and effectively “tunnel” through the passivation layer 30. In the preferred embodiment, aluminum oxide is used for its resistance to corrosion, its ability to passivate the N-Type semiconductor/aluminum interface 21, and for its inherent insulation properties. In an alternative embodiment, the passivation layer 30 is omitted, which may improve functionality but also increase wear to the device and reduce longevity. The thickness of the passivation layer 40 ranges between 10-1000 nanometers

[0030] The third layer is the N-Type metal oxide layer 21, and is the first part of the PN junction 20. In the preferred embodiment, the N-Type layer 21 comprises zinc oxide deposited through chemical vapor deposition. Zinc oxide has several properties that serve very important roles in the present invention. These properties include the exciton diameter length, which ranges between 20-100 mEv, as well as the 3d orbital to exhibit a desired behavior when conductivity type is measured. Furthermore, zinc oxide exhibits valence band anomalies, thus adding to the entropy of the PN junction 20 and the electrical generation, by proxy. The thickness of the N-Type layer 22 ranges between 10-1000 micrometers.

[0031] The fourth layer is the P-Type metal oxide layer 22, and is the second part of the PN junction 20. In the preferred embodiment, chromium III oxide is used for the P-Type layer 22 particularly because the conductivity type of chromium III oxide changes depending on the bias. In the preferred embodiment, the bias anomaly ranges between 2 and 10 mv. The thickness of the P-Type layer 22 ranges between 10-1000 micrometers.

[0032] The final layer is the negative terminal (anode) 50 for the thermophotovoltaic cell 10 that allows it to be introduced into an electrical circuit for the extraction of electricity. In the preferred embodiment, magnesium is used as the current collector due to amiable effects that magnesium has when used in conjunction with aluminum. Furthermore, since the electro-negativities of both metals differ only slightly, anodic oxidation is halted, and corrosion does not occur due to being electrically connected to a dissimilar metal. The thickness of the anode 40 ranges between 100-1000 micrometers.

[0033] The thickness of the PN junction 20 is contingent upon the application power requirements of the application for which it is used. More specifically, the power output of the thermophotovoltaic cell 10 is directly proportional to the thickness of the PN junction 20. In the preferred embodiment, the overall thickness of the thermophotovoltaic cell 10 ranges between 500-2500 micrometers.

[0034] In an alternative embodiment, two conductors of differing electronegativity are selected so as to provide a strong preference of current flow that the emitted electrons can follow. Here, the TPV cell comprises copper as the cathode 40 and aluminum magnesium alloy as the anode 50. Aluminum as well as magnesium can be utilized entirely by themselves. However, aluminum provides decreased power output and magnesium develops a non-conductive oxide layer which effectively contributes to parasitic behavior in the host cell due to poor contact at the metal/semiconductor interface. Therefore, an aluminum-magnesium alloy is desirable because it will not develop an oxide layer and the output power is at an acceptable level. After the conductive materials have been selected, the process of distributing the semiconductor substrates on the electrodes can be administered.

[0035] In a further alternative embodiment, the present invention provides a means of capturing the diffusion current integrated into its design in the form of the mirrored PN Junctions 20 with a common positive cathode 20 (see FIG. 2). All of these improvements effectively enhance the output power of the present invention as well as overcome the obstacles faced by other related devices. In yet a further alternative embodiment, an oxidizing agent, such as potassium permanganate, enhances the effect of ambient energy absorption to increase the amount of trap defects as well as interstitials and oxygen vacancies. These are the primary means of conduction via charge carriers such as electrons 23 and holes 29.

[0036] FIGS. 3 & 4 illustrate how the conduction band 26 of the N-Type semiconductor 25 and valence band 27 of the P-Type semiconductor 28 interact based on the amount of energy required to effectively excite a charge carrier from the valence band to the conduction band. This energy required is directly related to both materials fermi level 24, and difference thereof. The fermi level 24 of a body, defined as E.sub.F, is a thermodynamic quantity and its significance is the thermodynamic work required to add one electron to the body, not counting the work required to remove the electron from wherever it came from. A precise understanding of the fermi level, specifically how it relates to electronic band structure in determining electronic properties and how it relates to the voltage and flow of charge in an electronic circuit, is essential to an understanding of solid-state physics. FIG. 4 specifically illustrates how the P-Types 27, 28 positively charged electron holes 29 and the N-Types 25, 26 negatively charged valence electrons 23 interact when enough energy is absorbed by the lattice to overcome the fermi level 24.

[0037] The present invention is manufactured such that the components work in conjunction to produce electricity from heat. The method of manufacturing the present invention comprises placing a first substrate 40 into a chamber, forming a passivation layer 30 on the first substrate 40, forming a PN junction 30 on the passivation layer 30, forming a second substrate 50 on the PN junction 20, and annealing the first substrate 40, passivation layer 30, PN junction 20, and second substrate 50 in a vacuum chamber with inert atmosphere such as argon. Once annealed, the first substrate 40, passivation layer 30, PN junction 20, and second substrate 50 form the thermophotovoltaic cell 10.

[0038] There are several methods which can be used to form the thermophotovoltaic cell 10. In the preferred embodiment, the passivation layer 30, PN junction 20, and second substrate 50 are formed on the first substrate 40 through chemical vapor deposition for thin-film, solid-crystalline layers. Here, the thermophotovoltaic cell 10 is annealed between 450-660 degrees kelvin for 6-10 hours. In an alternative embodiment, the passivation layer 30, PN junction 20, and second substrate 50 are formed on the first substrate 40 through spin coating for thin, amorphous layers. In a further alternative embodiment, liquid-phase epitaxy can be used to form the layers.

[0039] While a particular form of the invention has been illustrated and described, it will be apparent that various modifications can be made without departing from the spirit and scope of the invention. For example, while certain materials have been presented, any suitable materials can be used so long as they are functionally equivalent to those presented. Accordingly, it is not intended that the invention be limited, except as by the appended claims

[0040] Particular terminology used when describing certain features or aspects of the invention should not be taken to imply that the terminology is being redefined herein to be restricted to any specific characteristics, features, or aspects of the invention with which that terminology is associated. In general, the terms used in the following claims should not be construed to limit the invention to the specific embodiments disclosed in the specification, unless the above Detailed Description section explicitly defines such terms. Accordingly, the actual scope of the invention encompasses not only the disclosed embodiments, but also all equivalent ways of practicing or implementing the invention.

[0041] The above detailed description of the embodiments of the invention is not intended to be exhaustive or to limit the invention to the precise form disclosed above or to the particular field of usage mentioned in this disclosure. While specific embodiments of, and examples for, the invention are described above for illustrative purposes, various equivalent modifications are possible within the scope of the invention, as those skilled in the relevant art will recognize. Also, the teachings of the invention provided herein can be applied to other systems, not necessarily the system described above. The elements and acts of the various embodiments described above can be combined to provide further embodiments.

[0042] All of the above patents and applications and other references, including any that may be listed in accompanying filing papers, are incorporated herein by reference. Aspects of the invention can be modified, if necessary, to employ the systems, functions, and concepts of the various references described above to provide yet further embodiments of the invention.

[0043] Changes can be made to the invention in light of the above “Detailed Description.” While the above description details certain embodiments of the invention and describes the best mode contemplated, no matter how detailed the above appears in text, the invention can be practiced in many ways. Therefore, implementation details may vary considerably while still being encompassed by the invention disclosed herein. As noted above, particular terminology used when describing certain features or aspects of the invention should not be taken to imply that the terminology is being redefined herein to be restricted to any specific characteristics, features, or aspects of the invention with which that terminology is associated.

[0044] While certain aspects of the invention are presented below in certain claim forms, the inventor contemplates the various aspects of the invention in any number of claim forms. Accordingly, the inventor reserves the right to add additional claims after filing the application to pursue such additional claim forms for other aspects of the invention.