Thermoelectric conversion device, preparation method thereof and thermal radiation system

Abstract

The invention provides a thermoelectric conversion device, a preparation method thereof and a heat radiation system. The thermoelectric conversion device comprises a thermal radiation emitter, a monocrystalline silicon substrate and a photovoltaic cell, wherein a sub-wavelength gap spacing distance is formed between the first side surface of the monocrystalline silicon substrate and the thermal radiation emitter; the photovoltaic cell is connected to a second side surface opposite to the first side surface of the monocrystalline silicon substrate. The thermal radiation emitter and the photovoltaic cell are integrated on the two sides of the monocrystalline silicon substrate, and the monocrystalline silicon substrate can completely inhibit sub-band gap thermal radiation transmission caused by surface modes such as surface phonons and polarons of the photovoltaic cell, so that unnecessary thermal transmission or thermal radiation is reduced or prevented, unnecessary heating of the photovoltaic cell is avoided, and the service life of the photovoltaic cell is prolonged. The thermoelectric conversion efficiency is improved; and meanwhile, the distance between the thermal radiation emitter and the monocrystalline silicon substrate is set as a sub-wavelength gap, so that the transmission efficiency of thermal radiation is greatly improved.

Description

Technical Field

[0001] The present disclosure relates to the field of thermal radiation technology, and in particular to a thermoelectric conversion device and a preparation method thereof, and a thermal radiation system. Background Art

[0002] Thermophotovoltaic technology is a technology that can directly convert thermal energy into electrical energy. It can convert the spectrum of radiation from any heat source, such as solar energy, industrial heat sources, waste heat from metallurgy and aerospace, bioenergy, chemical energy, etc., providing a good way for the effective utilization and recycling of energy.

[0003] At present, thermophotovoltaic technology (TPV, Thermo Photo Voltaic) can directly convert the infrared radiation energy of high-temperature objects into electrical energy through semiconductor materials, for example: through the thermal radiation emitter and photovoltaic cells to form a thermoelectric conversion device to convert thermal radiation.

[0004] However, in existing thermoelectric conversion devices, due to the structural design, photovoltaic cells support sub-bandgap thermal radiation transfer of surface phonon polaritons, which causes unnecessary heating of the photovoltaic cells and reduces the thermoelectric conversion efficiency. Summary of the invention

[0005] A technical problem to be solved by the present disclosure is the problem of low thermoelectric conversion efficiency of existing thermoelectric conversion devices.

[0006] In order to solve the above technical problems, the present disclosure provides a thermoelectric conversion device, which includes:

[0007] Thermal radiation emitters;

[0008] A single crystal silicon substrate, wherein a sub-wavelength gap exists between a first side surface of the single crystal silicon substrate and the thermal radiation emitter;

[0009] The photovoltaic cell is connected to the second side surface of the monocrystalline silicon substrate which is opposite to the first side surface.

[0010] In some embodiments, in the aforementioned thermoelectric conversion device, the thermal radiation emitter is a single crystal silicon thin film emitter, and the thickness of the thermal radiation emitter is 2-4 microns;

[0011] The photovoltaic cell is an indium gallium arsenide photovoltaic cell;

[0012] The thickness of the single crystal silicon substrate is 50-80 microns.

[0013] In some embodiments, the aforementioned thermoelectric conversion device, wherein the thermal radiation emitter comprises an emitter film;

[0014] The emitter film includes a first heat radiation area and a first connection area. The first connection area is connected to one end of the first heat radiation area through at least one narrow beam. The first connection area is used to adhere to a part of the first side surface of the single crystal silicon substrate.

[0015] In some embodiments, in the aforementioned thermoelectric conversion device, the first surface of the single crystal silicon substrate includes a second heat radiation region and a second connection region;

[0016] The second connection area is used to correspond to and fit the first connection area;

[0017] A step is formed between the second heat radiation area and the second connection area, so that the second heat radiation area is spaced apart from the first heat radiation area.

[0018] In some embodiments, in the aforementioned thermoelectric conversion device, a plurality of grooves are disposed on the second heat radiation region.

[0019] In some embodiments, in the aforementioned thermoelectric conversion device, the photovoltaic cell includes n-type indium phosphide, n-type indium gallium arsenide, a first p-type indium gallium arsenide, p-type indium phosphide, and a second p-type indium gallium arsenide stacked in sequence.

[0020] In some embodiments, the aforementioned thermoelectric conversion device, wherein the photovoltaic cell further comprises an insulating support substrate;

[0021] The insulating support substrate is arranged on a side of the second p-type indium gallium arsenide away from the p-type indium phosphide.

[0022] An embodiment of the second aspect of the present disclosure provides a heat radiation system, which includes at least one of the aforementioned thermoelectric conversion devices.

[0023] The third aspect of the present disclosure provides a method for preparing the thermoelectric conversion device, which comprises the following steps:

[0024] preparing a thermal radiation emitter;

[0025] preparing a single crystal silicon substrate;

[0026] Preparation of photovoltaic cells;

[0027] bonding the thermal radiation emitter and the single crystal silicon substrate;

[0028] Combined connection photovoltaic cells and monocrystalline silicon substrate.

[0029] In some embodiments, the method for preparing the thermoelectric conversion device described above, wherein the step of preparing the thermal radiation emitter comprises:

[0030] Depositing a silicon dioxide film on a first surface of a silicon substrate, and coating a silicon film on a second surface of the silicon substrate;

[0031] patterning the silicon thin film to form a first heat radiation region, a first connection region, and a narrow beam;

[0032] The steps of preparing a single crystal silicon substrate include:

[0033] Depositing a silicon dioxide film on a first surface of a silicon substrate and coating a silicon substrate on a second surface of the silicon substrate;

[0034] patterning the silicon substrate to form a stepped second heat radiation region and a second connection region;

[0035] The steps of bonding the thermal radiation emitter and the single crystal silicon substrate include:

[0036] The first connection region and the second connection region are bonded and connected under a specified temperature condition.

[0037] Through the above technical solution, the thermoelectric device provided by the present disclosure integrates a thermal radiation emitter and a photovoltaic cell on both sides of a single crystal silicon substrate. The single crystal silicon substrate can completely suppress the sub-bandgap thermal radiation transfer caused by the surface modes of the photovoltaic cell such as surface phonon polaritons, thereby reducing or preventing unnecessary heat transfer or thermal radiation, avoiding unnecessary heating of the photovoltaic cell, and improving the thermoelectric conversion efficiency; at the same time, in this solution, the distance between the thermal radiation emitter and the single crystal silicon substrate is set to a sub-wavelength gap, thereby greatly improving the transmission efficiency of thermal radiation. The problem of low thermoelectric conversion efficiency of existing thermoelectric conversion devices is effectively solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0039] Figure 1 is a schematic structural diagram of a thermoelectric conversion device disclosed in an embodiment of the present disclosure;

[0040] Figure 2 is a top view of a thermal radiation emitter in a thermoelectric conversion device disclosed in an embodiment of the present disclosure;

[0041] Figure 3 It is a schematic structural diagram of a single crystal silicon substrate in a thermoelectric conversion device disclosed in an embodiment of the present disclosure;

[0042] Figure 4 It is a schematic flow chart of the method for preparing the thermoelectric conversion device disclosed in the embodiment of the present disclosure.

[0043] Description of reference numerals:

[0044] 1. Thermal radiation emitter; 11. Emitter film; 12. First thermal radiation area; 13. First connection area; 14. Narrow beam; 2. Single crystal silicon substrate; 21. Second thermal radiation area; 22. Second connection area; 23. Step; 24. Groove; 3. Photovoltaic cell; 31. n-type indium phosphide; 32. n-type indium gallium arsenide; 33. First p-type indium gallium arsenide; 34. p-type indium phosphide; 35. Second p-type indium gallium arsenide; 36. Insulating support substrate; a. First direction. DETAILED DESCRIPTION

[0045] The following is a further detailed description of the embodiments of the present disclosure in conjunction with the accompanying drawings and examples. The detailed description of the following embodiments and the accompanying drawings are used to exemplarily illustrate the principles of the present disclosure, but cannot be used to limit the scope of the present disclosure. The present disclosure can be implemented in many different forms and is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

[0046] The present disclosure provides these embodiments to make the present disclosure thorough and complete, and to fully express the scope of the present disclosure to those skilled in the art. It should be noted that unless otherwise specifically stated, the relative arrangement of the parts and steps, the composition of the materials, the numerical expressions and the numerical values ​​set forth in these embodiments should be interpreted as being merely exemplary, and not as limiting.

[0047] It should be noted that, in the description of the present disclosure, unless otherwise specified, the meaning of "multiple" is greater than or equal to two; the terms "upper", "lower", "left", "right", "inner", "outer", etc., indicating the orientation or positional relationship, are only for the convenience of describing the present disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present disclosure. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0048] In addition, the words "first", "second" and similar words used in the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different parts. "Vertical" does not mean vertical in the strict sense, but is within the tolerance range. "Parallel" does not mean parallel in the strict sense, but is within the tolerance range. "Include" or "comprising" and similar words mean that the elements before the word include the elements listed after the word, and do not exclude the possibility of including other elements.

[0049] It should also be noted that in the description of the present disclosure, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present disclosure can be understood according to the specific circumstances. When a specific device is described as being located between a first device and a second device, there may or may not be an intermediate device between the specific device and the first device or the second device.

[0050] All terms used in the present disclosure have the same meanings as those understood by those of ordinary skill in the art to which the present disclosure belongs, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries, for example, should be interpreted as having meanings consistent with their meanings in the context of the relevant technology, and should not be interpreted in an idealized or extremely formal sense, unless explicitly defined as such herein.

[0051] At present, thermophotovoltaic technology (TPV) can directly convert infrared radiation energy of high-temperature objects into electrical energy through semiconductor materials, for example, by using a thermal radiation emitter and a photovoltaic cell to form a thermoelectric conversion device for thermal radiation conversion. However, in existing thermoelectric conversion devices, the thermal radiation emitter and the photovoltaic cell are designed separately, which requires additional positioning components, and the photovoltaic cell supports sub-bandgap thermal radiation transfer of surface modes such as surface phonon polaritons, which causes the photovoltaic cell to be heated unnecessarily, reducing the thermoelectric conversion efficiency.

[0052] The thermal radiation transmission efficiency between two objects separated by a subwavelength gap is several orders of magnitude greater than that in free space. Therefore, the thermoelectric conversion device provided in this embodiment integrates the thermal radiation emitter and the photovoltaic cell through a single crystal silicon substrate while maintaining the subwavelength gap between the thermal radiation emitter and the single crystal silicon substrate, thereby improving the thermal radiation transmission efficiency and also improving the thermoelectric conversion efficiency by suppressing the surface mode of the photovoltaic cell.

[0053] Example 1

[0054] Reference Figure 1 This embodiment discloses a thermoelectric conversion device, which includes a thermal radiation emitter 1, a single crystal silicon substrate 2 and a photovoltaic cell 3. The first side surface of the single crystal silicon substrate 2 and the thermal radiation emitter 1 have a sub-wavelength gap spacing distance; the photovoltaic cell 3 is connected to the second side surface of the single crystal silicon substrate 2 opposite to the first side surface thereof.

[0055] Specifically, in order to solve the problem of low thermoelectric conversion efficiency of existing thermoelectric conversion devices, the present embodiment provides a thermoelectric conversion device, in which a thermal radiation emitter 1 and a photovoltaic cell 3 are simultaneously integrated on both sides of a single crystal silicon substrate 2 to form an integrated thermoelectric conversion device, and a sub-wavelength gap between the thermal radiation emitter 1 and the single crystal silicon substrate 2 is maintained to improve the heat transfer efficiency from the thermal radiation emitter 1 to the photovoltaic cell 3; at the same time, the setting of the single crystal silicon substrate 2 can completely suppress the sub-bandgap thermal radiation transfer of the photovoltaic cell 3 caused by surface modes such as surface phonon polaritons, thereby reducing or preventing unnecessary heat transfer or thermal radiation, avoiding unnecessary heating of the photovoltaic cell 3, and thus greatly improving the thermoelectric conversion efficiency.

[0056] Among them, the thermoelectric conversion device provided in this embodiment can perform thermoelectric conversion in a high-temperature environment, and can also accelerate the application of near-field thermal radiation transmission in various fields such as solar energy collection and waste heat recovery; for example: in the high-temperature environment of 1400 degrees Celsius that lasts for 24 hours during the smelting process, the thermoelectric conversion device provided in this embodiment can recycle and utilize this high-temperature infrared radiation energy.

[0057] Among them, the thermal radiation emitter 1 is a device that can radiate energy outward in the form of electromagnetic waves under the high temperature condition of the heat source. It can be but not limited to emitting energy through infrared rays. In this embodiment, the thermal radiation emitter 1 is not limited to a plate structure or a film structure. The material of the thermal radiation emitter 1 can be designed and selected according to the degree of matching between its band gap capability and the band gap of the photovoltaic cell 3, and no further details will be given here. In this embodiment, the heat source used in conjunction with the thermal radiation emitter 1 can be but not limited to an isotope heat source, a concentrated light heat source, a heating production line heat source, a chemical reaction heat source, etc.

[0058] Among them, the single crystal silicon substrate 2 is an undoped silicon substrate, which serves as an integrated carrier of the thermal radiation emitter 1 and the photovoltaic cell 3, and the single crystal silicon substrate 2 is undoped so that it does not support any surface mode, and thus it can completely suppress the sub-bandgap thermal radiation transfer caused by the surface modes such as surface phonon polaritons of the photovoltaic cell 3, reduce or prevent unnecessary heat transfer or thermal radiation, avoid unnecessary heating of the photovoltaic cell 3, and the bandgap radiation loss is well suppressed, thereby greatly improving the thermoelectric conversion efficiency; at the same time, the single crystal silicon substrate 2 will gradually extract the electromagnetic mode (frustrated mode) restricted in the thermal radiation emitter 1 and transmit it to the photovoltaic cell 3 to enhance the near field of the bandgap thermal radiation transmission. Based on the fact that the thermal radiation transmission efficiency between two objects separated by a sub-wavelength gap is several orders of magnitude greater than the thermal radiation transmission efficiency in free space, in this embodiment, the spacing distance between the single crystal silicon substrate 2 and the thermal radiation emitter 1 is set to a sub-wavelength gap, thereby greatly improving the heat transfer efficiency, and the maintenance of the sub-wavelength gap can be achieved by structural support or by a suspension setting of the thermal radiation emitter 1.

[0059] The photovoltaic cell 3 is a device that can convert the photon energy of the visible light or infrared light part of the thermal radiation into electrical energy. The above content can be easily understood by those skilled in the art and will not be elaborated here.

[0060] According to the above, the thermoelectric device provided by the present disclosure integrates the thermal radiation emitter 1 and the photovoltaic cell 3 on both sides of the monocrystalline silicon substrate 2. The monocrystalline silicon substrate 2 can completely suppress the sub-bandgap thermal radiation transfer caused by the surface modes such as surface phonon polaritons of the photovoltaic cell 3, thereby reducing or preventing unnecessary heat transfer or thermal radiation, avoiding unnecessary heating of the photovoltaic cell 3, and improving the thermoelectric conversion efficiency; at the same time, in this solution, the distance between the thermal radiation emitter 1 and the monocrystalline silicon substrate 2 is set to a sub-wavelength gap, thereby greatly improving the transmission efficiency of thermal radiation. The problem of low thermoelectric conversion efficiency of existing thermoelectric conversion devices is effectively solved.

[0061] The term "and / or" in this article is merely a description of the association relationship of associated objects, identifying three possible relationships. For example, A and / or B is specifically understood as: A and B can be included at the same time, A can exist alone, or B can exist alone, and any of the above three situations can be met.

[0062] In some embodiments, the thermoelectric conversion device provided in this embodiment, in a specific implementation, the thermal radiation emitter 1 is a single crystal silicon thin film emitter, and the thickness of the thermal radiation emitter 1 is 2-4 microns; the photovoltaic cell 3 is an indium gallium arsenide photovoltaic cell; the thickness of the single crystal silicon substrate 2 is 50-80 microns.

[0063] It can be understood that in order to further improve the conversion efficiency of the thermoelectric conversion device, in this embodiment, the thermal radiation emitter 1 is set as a single crystal silicon thin film emitter, and the photovoltaic cell 3 is set as an indium gallium arsenide (InGaAs) photovoltaic cell, for example: 0.53 Ga 0.47 As photovoltaic cell, due to the inter-band transition, the silicon thin film emitter will generate thermal radiation in the near-infrared range at high temperature, wherein the band gap energy of silicon at a temperature of 1400K matches the band gap of In0.53Ga0.47As (0.73eV), which can suppress the sub-band gap heat transfer caused by the thermally excited free carriers of the thermal radiation emitter 1 and the doped free carriers in the photovoltaic cell 3, and realize the high absorption rate of receiving the thermal radiation of the thermal radiation emitter 1 without reflection; at the same time, in this embodiment, the thickness of the thermal radiation emitter 1 is relatively small, which can be 2 microns, 3 microns, 4 microns, etc., to suppress the sub-band gap absorption rate, thereby improving the thermoelectric conversion efficiency.

[0064] In some embodiments, refer to the attached Figure 2In the thermoelectric conversion device provided in this embodiment, the thermal radiation emitter 1 includes an emitter film 11; the emitter film 11 includes a first thermal radiation area 12 and a first connection area 13, the first connection area 13 is connected to one end of the first thermal radiation area 12 through at least one narrow beam 14, and the first connection area 13 is used to fit and connect a portion of the first side surface of the single crystal silicon substrate 2.

[0065] It can be understood that in order to achieve the spacing distance of the sub-wavelength gap between the thermal radiation emitter 1 and the single crystal silicon substrate 2, the thermal radiation emitter 1 is set in the form of an emitter film 11 in this embodiment, and the emitter film 11 is divided into two main parts, namely the first thermal radiation area 12 and the first connection area 13. The first thermal radiation area 12 is used to be spaced from the single crystal silicon substrate 2 for the transfer of thermal radiation, and the first connection area 13 is used to fit and connect with the single crystal silicon substrate 2. The narrow beam 14 is used to connect the first thermal radiation area 12 and the first connection area 13, so that the first thermal radiation area 12 can remain suspended relative to the first connection area 13; the first thermal radiation area 12, the first connection area 13 and the narrow beam 14 can be an integral structure, and the narrow beam 14 is formed on the same silicon thin film emitter by etching or photolithography. The number of narrow beams 14 can be designed and adjusted according to actual needs, for example: Figure 2 As shown, a single narrow beam 14 is provided, and the narrow beam 14 is located in the middle of the first heat radiation area 12 in the first direction a; when there are multiple narrow beams 14, they can be arranged at intervals in the first direction a to ensure stable suspension of the first heat radiation area 12.

[0066] Further, see Attachment Figure 3 In some embodiments, in the thermoelectric conversion device provided in this embodiment, the first surface of the single crystal silicon substrate 2 includes a second heat radiation area 21 and a second connection area 22; the second connection area 22 is used to correspond to the first connection area 21; a step 23 is formed between the second heat radiation area 21 and the second connection area 22 to separate the second heat radiation area 21 from the first heat radiation area 12.

[0067] It can be understood that in order to achieve the sub-wavelength gap spacing between the single crystal silicon substrate 2 and the thermal radiation emitter 1, in this embodiment, the first side surface of the single crystal silicon substrate 2 is set to be stepped, the second thermal radiation area 21 corresponds to the first thermal radiation area 12, and the second connection area 22 corresponds to the first connection area 13. The size of the second connection area 22 in the thickness direction of the single crystal silicon substrate 2 is larger than the size of the second thermal radiation area 21 in the thickness direction of the single crystal silicon substrate 2, and a step 23 is formed between the two. Then, when the first connection area 13 is bonded and connected to the second connection area 22, there is a gap between the first thermal radiation area 12 and the second thermal radiation area 21, and the gap is the distance of the sub-wavelength gap; in this embodiment, the first side surface of the single crystal silicon substrate 2 can be photolithographically or etched to thin part of the surface to form the second thermal radiation area 21; the bonding connection between the first connection area 12 and the second connection area 22 can be achieved by but not limited to wafer bonding technology.

[0068] Further, see Attachment Figure 1 and attached Figure 2 In some embodiments, in the thermoelectric conversion device provided in this embodiment, in a specific implementation, a plurality of grooves 24 are provided on the second heat radiation area 21 .

[0069] It can be understood that in order to prevent the first heat radiation area 12 and the second heat radiation area 21 from expanding and adhering at high temperature to affect the heat radiation efficiency, in this embodiment, a plurality of grooves 24 are provided in the second heat radiation area 21, and the depth of the grooves 24 can be a sub-wavelength gap, thereby ensuring that even when the first heat radiation area 12 and the second heat radiation area 21 expand under high temperature conditions, the groove 24 area can still maintain the sub-wavelength gap between the two, thereby avoiding excessive influence on the heat radiation efficiency; in this embodiment, the shape of the grass 24 is not limited here, and can be designed and adjusted according to actual needs, for example: Figure 3 In this embodiment, the number and position of the grooves 24 can be adjusted according to actual needs, and no further details will be given here.

[0070] In some embodiments, refer to the attached Figure 1 In the thermoelectric conversion device provided in this embodiment, in a specific implementation, the photovoltaic cell 3 includes an n-type indium phosphide 31, an n-type indium gallium arsenide 32, a first p-type indium gallium arsenide 33, a p-type indium phosphide 34 and a second p-type indium gallium arsenide 35 which are stacked in sequence.

[0071] It can be understood that in order to achieve high conversion efficiency when the photovoltaic cell 3 is combined with the thermal radiation emitter 1, the photovoltaic cell 3 in this embodiment is configured to include n-type indium phosphide 31 (n-InP), n-type indium gallium arsenide 32 (n-InGaAs), a first p-type indium gallium arsenide 33 (p-InGaAs), p-type indium phosphide 34 (p-InP) and a second p-type indium gallium arsenide 35 (p-InGaAs) stacked in sequence; the design of the stacked structure can reduce the recombination and scattering of photogenerated carriers during transmission, thereby reducing energy loss and improving photoelectric conversion efficiency; in addition, n-type indium gallium arsenide 32 (n-InGaAs) has a high absorption coefficient in the infrared range, and can be combined with n-type indium phosphide 31 (n-InP) to produce a wide spectrum response effect; indium phosphide and indium gallium arsenide both have high electron mobility, thereby accelerating the transmission speed of photogenerated carriers in the material, which is beneficial to improving the response speed and output power of the photovoltaic cell.

[0072] In some embodiments, the thermoelectric conversion device provided in this embodiment, in a specific implementation, the photovoltaic cell 3 further includes an insulating support substrate 36;

[0073] The insulating support substrate is arranged on a side of the second p-type indium gallium arsenide away from the p-type indium phosphide.

[0074] It can be understood that in order to ensure the stability of the photovoltaic cell 3 and even the entire thermoelectric conversion device, an insulating support substrate 36 is provided in the present embodiment, which can support and protect the stacked structure thereon while ensuring the electrical insulation of the photovoltaic cell 3; the insulating support plate 36 can be made of, but not limited to, glass, plastic, fiber-reinforced composite materials, gold (Au), titanium (Ti), silicon (Si), etc.

[0075] Example 2

[0076] This embodiment provides a heat radiation system including at least one thermoelectric conversion device.

[0077] It can be understood that the thermoelectric conversion device is the thermoelectric conversion device in Example 1. For its structure and working principle, please refer to the detailed description of Example 1, and no further details will be given here.

[0078] It can be understood that the thermal radiation system provided in this embodiment can be formed by a thermoelectric conversion device in conjunction with a production system under high temperature conditions, or a thermoelectric conversion device in conjunction with a chemical reaction system, or a thermoelectric conversion device in conjunction with a solar power generation system; the thermal radiation system provided in this embodiment utilizes the high-efficiency thermoelectric conversion of the thermoelectric conversion device to achieve high-speed and efficient electricity conversion and supply.

[0079] Example 3

[0080] Reference Figure 4 This embodiment provides a method for preparing a thermoelectric conversion device, which comprises the following steps:

[0081] 101. Prepare a thermal radiation emitter 1;

[0082] It can be understood that the specific preparation method of the thermal radiation emitter 1 in this embodiment can be to deposit a silicon dioxide film on the first surface of the silicon substrate and plate a silicon film on the second surface of the silicon substrate; then pattern the silicon film to form a first thermal radiation area 12, a first connection area 13 and a narrow beam 14. The silicon dioxide film and the silicon film can be prepared by ion beam sputtering deposition. During patterning, etching can be performed by electron beam lithography to form a narrow beam 14 and a first thermal radiation area 12 and a first connection area 13 located at both ends of the narrow beam 14. The silicon substrate serves as a molding carrier for the silicon film, and the silicon dioxide film can effectively ensure the molding of the silicon film. This setting can be easily understood by those skilled in the art, and will not be elaborated on here.

[0083] 102. Prepare a single crystal silicon substrate 2;

[0084] It can be understood that a silicon dioxide film is deposited on the first surface of the silicon substrate, and a silicon substrate is plated on the second surface of the silicon substrate; the silicon substrate is then patterned to form a stepped second heat radiation area 21 and a second connection area 22. The silicon dioxide film and the silicon substrate can be prepared by ion beam sputtering deposition. During patterning, etching can be performed by electron beam lithography or reactive ion etching to perform regional thinning on the surface of the silicon substrate to form a step to distinguish the second heat radiation area 21 and the second connection area 14. The silicon substrate serves as a molding carrier for the silicon substrate, and the silicon dioxide film can effectively ensure the molding of the silicon substrate. This setting can be easily understood by those skilled in the art, and will not be elaborated on here.

[0085] It is understandable that the above steps further include a step of performing secondary etching on the second heat radiation area 21 to form a plurality of grooves 24 , and the grooves 24 may be patterned by, but not limited to, reactive ion etching.

[0086] 103. Prepare photovoltaic cell 3;

[0087] It can be understood that the photovoltaic cell 3 can be prepared by metal organic vapor phase epitaxy to sequentially grow an epitaxial structure of n-type indium phosphide 31 (n-InP), n-type indium gallium arsenide 32 (n-InGaAs), a first p-type indium gallium arsenide 33 (p-InGaAs), p-type indium phosphide 34 (p-InP) and a second p-type indium gallium arsenide 35 (p-InGaAs) on an indium phosphide substrate (InP); of course, the process also includes the simultaneous preparation of the positive and negative electrodes of the photovoltaic cell 3, which can be easily understood by those skilled in the art and will not be elaborated on herein.

[0088] 104. Bonding the thermal radiation emitter 1 and the single crystal silicon substrate 2;

[0089] It can be understood that in this step, the thermal radiation emitter 1 and the single crystal silicon substrate 2 patterned in steps 101 and 102 need to be cleaned first, including but not limited to cleaning and hydrophilization operations; then the first connection area 13 and the second connection area 22 are wafer-bonded using a high-precision alignment and bonding system, so as to form a sub-wavelength gap between the first thermal radiation area 12 and the second thermal radiation area 21 and maintain this state.

[0090] It can be understood that in order to improve the bonding strength between the first connection area 13 and the second connection area 22, in this embodiment, the bonded thermal radiation emitter 1 and the single crystal silicon substrate 2 can be heated to 400-500K for 0.5-1 hour in a vacuum, and then placed in an Ar atmosphere and heated to 1200K for 1 hour to achieve surface activation, thereby improving the bonding strength.

[0091] 105. Combining and connecting the photovoltaic cell 3 and the monocrystalline silicon substrate 2;

[0092] It can be understood that the silicon substrate in the single crystal silicon substrate 2 is bonded to the thermal radiation emitter 1. In order to realize the combination of the silicon substrate and the photovoltaic cell 3, in this embodiment, the silicon dioxide film and the silicon substrate on the silicon substrate need to be removed first. The silicon dioxide film and the silicon substrate can be removed by, but not limited to, sulfur hexafluoride (SF6) gas and hydrofluoric acid (HF) solution to expose the silicon substrate, and then activated by oxygen plasma and annealed at 400-450K in vacuum for 0.5-1 hour to realize the combination of the silicon substrate and the epitaxial structure, that is, the combination of the single crystal silicon substrate 2 and the photovoltaic cell 3.

[0093] It can be understood that after the above steps, the indium phosphide substrate (InP) of the photovoltaic cell 3 can be removed on the side of the epitaxial structure away from the single crystal silicon substrate 2 by using a hydrochloric acid (HCL) solution, and then the insulating support substrate 36 can be fixed to the epitaxial structure with the substrate removed by flip-chip bonding using a conductive adhesive (silver paste).

[0094] It is understandable that after the above steps, the silicon dioxide film and silicon substrate on the thermal radiation emitter 1 can be removed by sulfur hexafluoride (SF6) gas and hydrofluoric acid (HF) solution to expose the silicon film, thereby completing the entire preparation process of the thermoelectric conversion device.

[0095] So far, various embodiments of the present disclosure have been described in detail. In order to avoid obscuring the concept of the present disclosure, some details known in the art are not described. Based on the above description, those skilled in the art can fully understand how to implement the technical solution disclosed here.

[0096] Although some specific embodiments of the present disclosure have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present disclosure. It should be understood by those skilled in the art that the above embodiments may be modified or some technical features may be replaced by equivalents without departing from the scope and spirit of the present disclosure. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there is no structural conflict.

Claims

1. A thermoelectric conversion device, characterized in that: It includes: Thermal radiation emitter (1); A single crystal silicon substrate (2), wherein a sub-wavelength gap exists between a first side surface of the single crystal silicon substrate (2) and the thermal radiation emitter (1); A photovoltaic cell (3), the photovoltaic cell (3) being connected to a second side surface of the monocrystalline silicon substrate (2) opposite to the first side surface thereof.

2. The thermoelectric conversion device according to claim 1, characterized in that: The thermal radiation emitter (1) is a single crystal silicon thin film emitter, and the thickness of the thermal radiation emitter (1) is 2-4 microns; The photovoltaic cell (3) is an indium gallium arsenide photovoltaic cell; The thickness of the single crystal silicon substrate (2) is 50-80 microns.

3. The thermoelectric conversion device according to claim 1, characterized in that: The thermal radiation emitter (1) comprises an emitter film (11); The emitter film (11) comprises a first heat radiation area (12) and a first connection area (13), wherein the first connection area (13) is connected to one end of the first heat radiation area (12) via at least one narrow beam (14), and the first connection area (13) is used to adhere to a portion of the surface of the first side surface of the single crystal silicon substrate (2).

4. The thermoelectric conversion device according to claim 3, characterized in that: The first surface of the single crystal silicon substrate (2) comprises a second heat radiation area (21) and a second connection area (22); The second connecting area (22) is used to correspond to and fit the first connecting area (21); A step (23) is formed between the second heat radiation area (21) and the second connection area (22), so that the second heat radiation area (21) is spaced apart from the first heat radiation area (12).

5. The thermoelectric conversion device according to claim 4, characterized in that: A plurality of grooves (24) are provided on the second heat radiation area (21).

6. The thermoelectric conversion device according to claim 1, characterized in that: The photovoltaic cell (3) comprises an n-type indium phosphide (31), an n-type indium gallium arsenide (32), a first p-type indium gallium arsenide (33), a p-type indium phosphide (34) and a second p-type indium gallium arsenide (35) which are stacked in sequence.

7. The thermoelectric conversion device according to claim 6, characterized in that: The photovoltaic cell (3) further comprises an insulating support substrate (36); The insulating support substrate (36) is arranged on a side of the second p-type indium gallium arsenide (35) away from the p-type indium phosphide (34).

8. A heat radiation system, characterized in that: It includes: At least one thermoelectric conversion device according to any one of claims 1 to 7.

9. A method for preparing a thermoelectric conversion device according to any one of claims 1 to 7, characterized in that: It includes the following steps: preparing a thermal radiation emitter (1); preparing a single crystal silicon substrate (2); Preparation of photovoltaic cells (3); Bonding the thermal radiation emitter (1) and the single crystal silicon substrate (2); The photovoltaic cell (3) and the single crystal silicon substrate (2) are combined and connected.

10. The method for preparing a thermoelectric conversion device according to claim 9, wherein: The steps of preparing a thermal radiation emitter include: Depositing a silicon dioxide film on a first surface of a silicon substrate, and coating a silicon film on a second surface of the silicon substrate; Patterning the silicon thin film to form a first heat radiation region (12), a first connection region (13) and a narrow beam (14); The steps of preparing a single crystal silicon substrate include: Depositing a silicon dioxide film on a first surface of a silicon substrate and coating a silicon substrate on a second surface of the silicon substrate; Patterning the silicon substrate to form a stepped second heat radiation region (21) and a second connection region (22); The step of bonding the thermal radiation emitter (1) and the single crystal silicon substrate (2) comprises: The first connection region (13) and the second connection region (22) are bonded and connected under specified temperature conditions.

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