Thermo-photovoltaic structure, for ambient and high temperatures, with a stack of thermo-photovoltaic cells, one end face of which is coated with a radiative material, associated thermo-photovoltaic plate and module.

Abstract

Thermo-photovoltaic structure, for ambient and high temperatures, with a stack of thermo-photovoltaic cells, one end face of which is coated with a radiative material. Associated thermo-photovoltaic plate and module. The invention relates to a thermo-photovoltaic structure (10) comprising: - an alternating stack of thermo-photovoltaic cells (1; 1.1, 1.2, 1.3) and output electrodes such as to connect the cells in series and / or in electrical parallel; - at least one coating (12) of a material, called the radiative material, suitable for dissipating heat from the external environment by radiative cooling, arranged on at least one end face of the stack, such that the infrared radiation emitted by the black body of the coating is converted by the cells into electricity. Figure for the abstract: Fig. 2

Description

Title of the invention: Thermo-photovoltaic structure, for ambient and high temperatures, with a stack of thermophotovoltaic cells, one end face of which is coated with a radiative material, Associated thermo-photovoltaic plate and module. technical field

[0001] The present invention relates to the thermo-photovoltaic field, that is to say the field of the conversion of heat directly into electricity.

[0002] It aims to improve existing thermo-voltaic solutions by significantly increasing the efficiency of current photovoltaic panels or by generating electricity through direct conversion of heat from an environmental medium. Prior art

[0003] Photovoltaic cells are known to convert solar radiation into electricity. More precisely, photovoltaic cells convert the energy of electromagnetic waves into electricity by taking advantage, on the one hand, of the ambivalence of semiconductor materials, in which electrons from lower layers are promoted towards the conduction band under the effect of illumination by photons of sufficient energy, and on the other hand, of the juxtaposition of such materials, doped on the one hand positively, on the other hand negatively, these dopings allowing the establishment of a potential difference in the absence of any illumination between them but allowing, during their illumination, the movement of electrons appearing in the conduction band towards the negatively doped material.

[0004] Thus, the major drawback of photovoltaic cells is that they only work during the day, i.e. in the presence of solar radiation.

[0005] Unlike conventional photovoltaics, which directly convert photons into electrons, there are thermophotovoltaic cells that convert electromagnetic radiation emitted in the infrared into electricity: [1] In other words, they convert heat into electricity. The major drawback of known thermophotovoltaic cells is that they convert near-infrared radiation, typically obtained at high temperatures of around 10,000°C or from the sun. Furthermore, these high temperatures preclude the use of organic thermophotovoltaic cells.

[0006] Indeed, silicon is most often used as the semiconductor material in the production of these cells. Other materials have already been used, such as gallium arsenide (GaAs), gallium-indium arsenide (GalnAs), the Aluminum-gallium-indium phosphide (AlGalnP), or semiconductor polymers, whose wide variety allows for the selection of the band gap, which is the energy difference between the conductive and valence bands and also corresponds to the minimum photon energy required to generate an electric current. For the near and mid-infrared, an indium gallium arsenite antimonide alloy (InxGai_xAsySbi_y) can be used, whose band gap varies between 0.5 eV and 0.6 eV depending on the values ​​of x and y. However, the infrared wavelengths emitted by black bodies at room temperature have energies primarily between one-twentieth of an electron volt and half an electron volt, rarely corresponding to the direct band gaps of semiconductors, which are on the order of an electron volt.

[0007] Quantum wells, particularly one-dimensional ones, can then be created, consisting of a semiconductor sandwiched between two other layers of one or more different semiconductors with a larger band gap. The area occupied by the sandwiched semiconductor then has an intermediate band gap, enabling the voltaic effect with lower-energy photons, especially if doping of the sandwich layers and, a fortiori, the intermediate layers allows the development of an electric field across the cell. For example, InO₂.7Gao₂.3As can be used for the low-band gap semiconductor and AlAso₂.8Sb₂.2 as the semiconductor with a higher band gap:[2]. For example, the semiconductors could be Pbo₂.8iSno₂.19Se as a low-band gap material combined with Pbo₂.so₂Sr₂.20Se:[3].

[0008] It is also possible to create between the two sandwich layers not a quantum well but a stack of quantum wells called a quantum cascade, made of layers of different thicknesses, thus creating a succession of quantum wells having different gaps. These can be two semiconductors with different gaps: [2].

[0009] These quantum cascades make it possible to generate electricity also in this mid-infrared range, in particular from radiation with a wavelength of 9qm: [4], the wavelength at which black bodies emit at a temperature of 25°C.

[0010] These layers can be stacked on top of each other to form multi-junction cells and convert most of the spectrum into electricity: [5].

[0011] Furthermore, to overcome the limitations of the efficiency of multi-junction cells, often less than 50% in the visible spectrum, a system has been proposed for converting light radiation into intense heat, on the order of 1000°C, and then converting infrared radiation into light in the visible spectrum absorbable by photovoltaic cells: [6].

[0012] However, the proposed system is complicated to implement, requires heating the device by light rays at high temperatures and does not allow direct conversion into electricity of thermal energy from ambient heat, a sea, an ocean or any other aquatic environment or those encountered by a standard photovoltaic solar panel during its use.

[0013] Furthermore, there are thermoelectric generators using the Thomson effect. However, these require two heat reservoirs at different temperatures, one supplying heat and the other absorbing it.

[0014] There is therefore a need to propose a thermo-voltaic solution in particular so that it is adapted to usual environmental temperatures, with a view both to significantly increase the efficiency of current photovoltaic panels and to generate electricity by direct conversion of heat from an environmental environment.

[0015] The invention aims to meet all or part of this need. Description of the invention

[0016] To this end, the invention relates, according to one of its aspects, to a thermo-photovoltaic structure comprising:

[0017] - an alternating stack of thermo-photovoltaic cells and output electrodes so as to connect the cells in series and / or in electrical parallel;

[0018] - at least one coating made of a material, called a radiative material, adapted to absorb and dissipate heat from the external environment by radiative cooling, arranged on at least one of the end faces of the stack, so that the infrared radiation emitted by the radiative material is converted by the cells into electricity.

[0019] Thus, the invention essentially consists of creating a thermophotovoltaic structure with thermo-photovoltaic cells stacked one on top of the other, at least one end face being coated with a radiative material.

[0020] Thermo-photovoltaic cells are advantageously configured to absorb heat at infrared wavelengths emitted by black bodies at the temperatures of the radiating material. Preferably, the thermo-photovoltaic cells are configured to absorb infrared wavelengths between 5 and 50 pm.

[0021] Thermo-photovoltaic cells are advantageously configured for the radiative material coating to operate at a given temperature, for example 20°C, 0°C, 45°C, or 80°C, and to produce an electric current of a limited number of predefined intensities, for example 120A and 600A for operation at 20°C, allowing cells operating at the same current to be connected in series, as well as cells or groups of cells. operating at the same voltage in parallel. Advantageously, each thermophotovoltaic cell is made of organic and / or inorganic semiconductor materials.

[0022] According to an advantageous embodiment, at least one of the thermophotovoltaic cells consists of two lower and upper electrodes, arranged on either side of at least one stack of three successive thin layers forming a quantum well as follows:

[0023] - a layer based on a wide bandgap semiconductor material doped with P-type donors;

[0024] - a layer based on a low bandgap semiconductor material doped by P-type donors;

[0025] - a layer based on a wide bandgap semiconductor material doped with type N acceptors.

[0026] According to another advantageous embodiment, at least one of the thermophotovoltaic cells consists of two lower and upper electrodes arranged on either side of at least one stack of three successive thin layers forming a quantum well as follows:

[0027] - a layer based on a wide bandgap semiconductor material doped with P-type donors;

[0028] - a layer based on a low bandgap semiconductor material doped by N-type acceptors;

[0029] - a layer based on a wide bandgap semiconductor material doped with type N acceptors.

[0030] Preferably, the wide band gap semiconductor material is an indium (In) and gallium (Ga) alloy, more preferably the Ino.7Gao.3As alloy.

[0031] Preferably, the Ino.7Gao.3Asa alloy layer has a thickness between 300 and 2000 nm.

[0032] Preferably, the wide bandgap semiconductor material is an aluminum arsenide (AlAs) or aluminum antimonide (AlSb) alloy or their combination, preferably the AlAso.8Sbo.2 alloy.

[0033] Preferably, the AlAso.8Sbo.2a alloy layer has a thickness between 28 and 80 nm.

[0034] According to an advantageous variant, at least one thermo-photovoltaic cell comprises several quantum wells stacked one on top of the other, forming a quantum cascade.

[0035] Thermo-photovoltaic cells are preferably configured to absorb infrared wavelengths between 5 and 50 pm.

[0036] The structure is advantageously configured to produce electrical currents between 15 and 600A per m2.

[0037] According to an advantageous configuration, the cell(s) of the stack absorbing the shortest wavelengths is / are arranged closest to the radiative material coating, while the cell(s) furthest away absorb(s) higher wavelengths.

[0038] Advantageously, the radiative material coating is made of thermally conductive material, preferably aluminum.

[0039] The radiative material coating can be of planar shape.

[0040] Advantageously, the radiative material is in contact with heat dissipation fins that extend into the external environment.

[0041] According to an advantageous embodiment, the radiative material is coated with a thermal protection film on its outer face, opposite that arranged on the stack of thermo-photovoltaic cells, said thermal protection film being adapted to reflect thermal radiation in the infrared range. Thermo-photovoltaic cells

[0042] Since the band gap of the sandwiched material has a band energy inversely proportional to the square of its thickness, it is possible, by choosing said thickness, to create thermo-photovoltaic cells absorbing thermal radiation of high wavelengths.

[0043] Thermo-photovoltaic cells are preferably made of quantum wells, for example in Pb0,8Sr0,2Se and, for, the low band gap material of PbOj8iSnOji 9Se, whose layers in low band gap materials are of thicknesses between 1 and 10 crystal monolayers, i.e. of a thickness between 0.35nm and 3.5nm.

[0044] Alternatively, thermo-photovoltaic cells are preferably made of quantum cascades, for example in Pbo,8Sro,2Se and, for the low-bandgap material, Pbo,8iSno,i9Se, whose layers of low-bandgap materials have different thicknesses ranging from 1 to 15 crystal monolayers, i.e., a thickness between 0.35 nm and 5.25 nm, while the layers made of higher-bandgap materials are Inm thick. The bandgap layers of these quantum cascades are advantageously stacked one on top of the other, allowing, from the radiative material, first the absorption of the most energetic radiation, i.e., of the longest wavelengths, and then the absorption of the least energetic radiation.

[0045] Alternatively, the cell absorbing electromagnetic waves of the lowest frequency of radiation absorbed by the cells of the The structure is arranged in the middle of the stack in such a way that the electromagnetic radiation entering the thermo-photovoltaic structure, through either of its end faces, is first absorbed at its shorter wavelengths, then at its longer wavelengths. The cell absorbing the electromagnetic waves is then advantageously flanked on each of its faces by at least one radiative material.

[0046] Alternatively, thermophotovoltaic cells use semiconductor nanoparticles called quantum dots, preferably with direct band gaps, preferably between 0.05 eV and 0.5 eV, made for example of Lead Sulfide PbS, Mercury Sulfide HgS, Tiemannite HgSe, Mercury Telluride HgTe or indium tin oxide doped to have band gaps in the mid and far infrared range: [7]. Layers of these nanoparticles with different band gaps are advantageously stacked one on top of the other, allowing the radiating material to first absorb the most energetic radiation, i.e., the shortest wavelengths, and then absorb the less energetic radiation.

[0047] Alternatively, a layer absorbing electromagnetic waves of the lowest frequency of radiation absorbed by the various layers is located in the middle of said other layers such that the electromagnetic radiation penetrating the thermo-photovoltaic cell is first absorbed in its shortest wavelengths, then in its longer wavelengths as it enters the thermo-photovoltaic cell through one of its faces or the other.

[0048] A magnesium layer can advantageously be sandwiched between layers of nanoparticles: [8]. These nanoparticle layers are, for example, sandwiched between two semiconductors, one positively doped and the other negatively doped. Alternatively, these nanoparticle layers are sandwiched, for example, between two layers of semiconductor polymers, one called the donor and the other the receiver. Alternatively still, nanoparticles are included in one of the polymers forming the thermo-photovoltaic cells: [9]. Preferably, the nanoparticles are included in successive layers of different particle sizes, allowing them to first absorb the most energetic rays from the electrode, which is transparent to blackbody radiation.

[0049] According to an advantageous embodiment, the face of the thermophotovoltaic cell stack furthest from the radiating material is coated with a thermal protection film adapted to reflect thermal radiation in the infrared range.

[0050] Advantageously, the thermal protection film is a Bragg mirror.

[0051] According to this embodiment, the radiative material is coated with a first thermal protection film on its outer face, opposite that arranged on the stack of thermo-photovoltaic cells, and / or the outer face of the stack of thermo-photovoltaic cells is coated with a second thermal protection film; said thermal protection films being adapted to reflect thermal radiation in the infrared range; The first thermal protection film prevents the black body from cooling by thermal radiation on the side of the structure not equipped with the thermo-photovoltaic cells. The second thermal protection film reflects the radiation not absorbed by the infrared-absorbing layers of the structure. Bragg Mirror

[0052] A Bragg mirror is for example made up of layers of materials transparent to the infrared emitted by black bodies and of differentiated refractive indices in alternation.

[0053] The layers are made up, for example, of Gallium Arsenide (GaAs) and Potassium Chloride (KCl), whose refractive indices are respectively 3.2971 and 1.4705.

[0054] The thickness of a layer of GaAs is therefore equal to 5 / 4 / 3.2971 or 0.38 qm, while the thickness of a layer of KC1 is 0.85 qm; such a mirror reflects, according to the inventor's calculations, radiation with wavelengths between 3.3 qm and 10 qm.

[0055] A Bragg mirror made of layers of Cadmium telluride CdTe and KC1, which have refractive indices of 2.65 and 1.432 respectively and layers of thicknesses of 0.47qm and 0.87qm respectively, reflects, according to the inventor's calculations, radiation with wavelengths between 3.6qm and 8.1qm.

[0056] Each of the two mirrors can be made up of 8 pairs of layers. It is possible to arrange two Bragg mirrors, of different materials, one adjacent to the other.

[0057] Thermo-photovoltaic cells can be connected in series and / or in parallel to obtain an electric current between only two output terminals of the structure. For example, for operation at 20°C with thermo-photovoltaic cells producing electric currents of 120A and 600A per m², the output electrodes of cells producing 120A are preferably connected in parallel, in particular in groups of 5 to form two substructures producing 600A each. Each of these substructures, as well as the cells intrinsically producing 600A, are preferably connected in series to produce an electric current of 600A under a cumulative voltage of each of the cells not connected in parallel and with the substructures.

[0058] By way of example, according to the inventor's calculations, assuming an external quantum efficiency (EQE) of 1, the power per m2 of surface of a stack consisting of a first group of 5 layers in parallel each producing an intensity of 120A for a potential difference of 0.02V, said first group being put in series with a second group consisting of 11 layers in series producing an intensity of 600A for a cumulative potential difference of 0.77V and put in series with a third group consisting of a set of 5 layers in parallel and having a potential difference of 0.16V and each producing an intensity of 120A, produces approximately 540W at 20°C, 295W at -10°C, 440W at +10°C and 630W at 37°C.

[0059] By way of another example, according to the inventor's calculations assuming an external quantum efficiency of 1, the power per m2 of surface of a stack consisting of 7 layers in series producing an intensity of 900A for a cumulative potential difference of 0.45V in series with a set of 4 layers in parallel and having a potential difference of 0.13V and a cumulative intensity of 900A, produces approximately 490W at 20°C, 290W at -10°C, 420W at +10°C and 570W at 37°C.

[0060] The electrical connections of the layers are advantageously reconfigurable, allowing the thermo-photovoltaic structure to be adapted to the temperature at which it is used.

[0061] Alternatively, the substructures connected in electrical series and producing different intensities each have their own current output.

[0062] Alternatively, each of the cells produces an electric current of a single intensity, for example 600A at 20°C.

[0063] Preferably, the cells of the stack absorbing shorter wavelengths are arranged closer to the radiative material coating than the cells absorbing longer wavelengths.

[0064] A radiative material coating according to the invention emits electromagnetic radiation in the infrared range, preferably near and mid-infrared. It is preferably thermally conductive, such as, for example, aluminum, copper, or carbon fiber. Alternatively, it can be a composite material, such as, for example, copper coated with carbon nanoparticles known as carbon black. Like a carbon nanotube coating, the radiative material can absorb radiation of other wavelengths, for example, in the visible range.

[0065] The invention also relates to a thermo-photovoltaic plate comprising at least two thermo-photovoltaic structures as described above, stacked one on top of the other and electrically connected in series and / or in parallel.

[0066] According to an advantageous embodiment, the plate comprises one or more uprights of thermally conductive material passing through the thermophotovoltaic structures so as to constitute thermal bridges between the radiative material coating(s) at at least one end of the stack of structures and the radiative material(s) within the stacked structures.

[0067] The invention also relates to a thermo-photovoltaic module comprising at least two thermo-photovoltaic plates as described above, spaced apart from each other by a space suitable for circulating a heat transfer fluid.

[0068] The invention also relates to the use of a thermo-photovoltaic module as mentioned above by immersion in an external surrounding environment, so that its fluid, such as water from an aquatic environment, or ambient air, circulates by natural or forced convection within the module.

[0069] The advantages of the invention compared to state-of-the-art photovoltaic and thermo-photovoltaic panels are numerous, including:

[0070] - increased electricity production;

[0071] - the possibility of operating a thermo-photovoltaic module in immersing / implanting it in any natural environment, such as seas, lakes, waterways (rivers, streams, rivers), in soil, in ambient air, at great depths, particularly to recover geothermal heat or to capture heat from overheated rooms or computer servers;

[0072] - the possibility of integrating a thermo-photovoltaic module with electrical efficiency high, directly in an electrically powered device / equipment / machine / vehicle / boat so as to increase overall efficiency and / or make it self-sufficient. For example, a thermo-photovoltaic module according to the invention can be placed inside a refrigeration unit and utilize the heat it extracts, or outside a motor vehicle under or on its bodywork, behind the hull of a boat, under clothing to cool the body and generate energy, or implanted as an electricity-generating device inside a human, plant or animal body to, for example, electrically power medical implants, or to power autonomous electrical devices such as surveillance cameras or GPS beacons.

[0073] Other advantages and features of the invention will become clearer from the detailed description of examples of implementation of the invention given by way of illustration and not limitation with reference to the following figures. Brief description of the drawings

[0074] [Fig-1] [Fig. 1] represents a partial cross-sectional view of an example of a thermo-photovoltaic cell according to the invention.

[0075] [Fig.2] [Fig.2] is a partial cross-sectional view of an example of a thermo structure photovoltaic according to the invention comprising a stack of thermophotovoltaic cells according to [Fig.1] and a coating of radiative material on one of the end faces of the stack.

[0076] [Fig.3] [Fig.3] is a partial cross-sectional view of an example of a panel thermo-photovoltaic according to the invention comprising a stack of thermo-photovoltaic structures according to [Fig.2] crossed by uprights forming thermal bridges between the radiative material coatings.

[0077] [Fig.4] [Fig.4] is a partial cross-sectional view of an example of a thermo module photovoltaic according to the invention comprising a plurality of thermophotovoltaic panels according to [Fig.3] spaced apart from each other allowing a heat transfer fluid to circulate from an external environment.

[0078] [Fig.5] [Fig.5] is a partial cross-sectional view of another example of a cell Organic type thermo-photovoltaic. Detailed description

[0079] Throughout this application, the terms "above" and "below" are to be understood in relation to a thermo-photovoltaic structure according to the invention which would be in a horizontal operating configuration.

[0080] The different elements are not necessarily on the same scale, for the sake of clarity only.

[0081] Figure 1 shows an example of a thermo-photovoltaic cell 1 according to the invention. It consists of a successive stacking of the following layers: - a layer 2 based on a wide bandgap semiconductor material doped with P-type donors; - a layer 3 based on a low band gap semiconductor material doped with P-type donors; - a layer 4 based on wide bandgap semiconductor material doped with N-type acceptors.

[0082] Layer 2 is for example based on P-doped Ino.7Gao.3As and of thickness between 300nm and 2000nm.

[0083] Layer 3 is for example based on P-doped AlAso.8Sbo.2 and has a thickness between 28 and 80 nm.

[0084] Layer 4 is for example based on N-doped Ino.7Gao.3As and has a thickness between 300nm and 2000nm.

[0085] Two electrodes 5, 6 respectively electrically connected to layers 2, 4 ensure the output of the electric current.

[0086] According to the invention, a thermo-photovoltaic structure is produced by stacking several thermo-photovoltaic cells alternately with their output electrodes, and by applying a coating of radiative material, in particular aluminum, to one end face of the stack.

[0087] In the illustrated example in [Fig. 2], the structure 10 consists of a stack of four thermo-photovoltaic cells 1.1, 1.2, 1.3, 1.4 and a coating of aluminum radiative material deposited on the top cell. All cells 1.1 to 1.4 are electrically connected in series so that the structure 10 comprises only two output terminals 13, 14.

[0088] A heat transfer fluid F circulating by natural or forced convection, such as air or water, or a refrigerant such as Freon, heats the radiating coating 2. As illustrated by the black arrows, black bodies at the temperatures of the radiating coating 2 then emit radiation in the infrared range, preferably with wavelengths between 5 and 50 pm, for which the cells 1.1, 1.2, 1.3, and 1.4 are adapted, and thus produce electricity. In other words, the heat from the heat transfer fluid F, absorbed by the radiating coating 2, is converted into electricity by the cells 1.1, 1.2, 1.3, and 1.4 with optimal efficiency.

[0089] A thermo-photovoltaic plate P can be made by stacking several structures 10, as illustrated in [Fig. 3], their radiative material coatings 2 being either within the stack or on the end face, with only two electrical output terminals 15, 16. For example, ten thermo-photovoltaic structures 10 can be stacked to form a plate with a total thickness of 2 cm producing up to 5400 W / m² at a fluid temperature F of approximately 20°C.

[0090] As illustrated in this [Fig.3], metal uprights 100 advantageously pass through the stack of a plate to thermally connect the different radiative materials 2 together by forming thermal bridges, which optimizes thermal conduction within the plate P. For example, the thermal bridges 100 are regularly spaced at a distance of 1 to a few cm.

[0091] A thermo-photovoltaic module M according to the invention may comprise several plates PI, P2, P3 arranged at a distance from each other and electrically connected to each other with only two electrical output terminals 17, 18, as shown in [Fig. 4]. The heat transfer fluid F may circulate in the spaces of height e1, e2 between the plates.

[0092] By way of example, a module M which has just been described with a stack of thermo-photovoltaic plates PI, P2, P3 of a number of ten plates 10 each, Regularly spaced at a height el = e2 of approximately 2 cm, for a total cubic volume of 1 m³, immersed in a fluid F such as seawater or a river at 20°C, would generate up to 21 kW of electricity. The water passing through the module would then be cooled by less than 0.01°C if it circulates at Im / s in the sea or river.

[0093] As another example, a plate P on a surface of 5.5m2 installed on the body of a vehicle traveling at 30m / s would generate 30kW by cooling the air F by less than 0.5°C, thus allowing the vehicle to move.

[0094] As another example of application, a plate P can be arranged on the fuselage and / or wings of an aircraft, in particular a supersonic aircraft, to recover thermal energy.

[0095] Another example of the realization of a thermo-photovoltaic cell, of organic type which can be envisaged within the framework of the invention is illustrated in [Fig.5].

[0096] The thermo-photovoltaic cell 1 is here made up of a successive stacking of the following layers:

[0097] - a layer 20 based on an n-type organic polymer which constitutes an acceptor of electrons;

[0098] - a layer 30 based on a polymer which constitutes an acceptor;

[0099] - a layer 40 based on a p-type conductive polymer which constitutes a donor.

[0100] Layer 20 is for example based on a [6,6]-phenyl-C61-methyl butanoate polymer (PCBM) and has a thickness between 100nm and 100nm, preferably equal to 15nm. Where appropriate, the PCBM polymer may incorporate nanoparticles.

[0101] The layer 30 is for example based on a poly-3-oxothieno[3,4-d]isothiazole-l,l-dioxide / benzodithiophene polymer, and of thickness between 10 and 50 nm, preferably equal to 15nm.

[0102] The layer 40 is for example based on a poly(3-hexylthiophene-2,5-diyl) (P3HT) polymer and of thickness between 100nm and 100nm, preferably equal to 15nm. Where appropriate, the P3HT polymer may incorporate nanoparticles.

[0103] Two electrodes 50, 60 respectively, electrically connected to layers 20, 40, provide the output of the electric current. Either of the layers 50, 60 may be an indium tin oxide (ITO) layer. Typically, the thickness of the ITO layer may be equal to Ipm.

[0104] An additional layer 70 of zinc oxide (ZnO) can be intercalated between layer 40 and electrode 60. Typically, the thickness of the ZnO layer can be equal to 10m. Other variations and improvements can be envisaged without departing from the scope of the invention.

[0105] If in the illustrated examples, layers 2, 3, 4 of a thermophotovoltaic cell are respectively doped P, P, N, we can very well consider a stacking of layers 2, 3, 4 respectively doped P, N, N.

[0106] If, in the example illustrated in [Fig. 2], a thermo-photovoltaic structure according to the invention comprises a stack of four cells, any number starting from two can be considered. The same applies to a thermo-photovoltaic panel and module according to the invention.

[0107] In a thermo-photovoltaic module according to the invention, the plates can be regularly spaced from each other or with spaces of different widths.

[0108] In the illustrated examples, the electrical connections shown between cells within a structure, between structures within a panel, and between panels within a module are exclusively in series. Series and / or parallel electrical connections are entirely conceivable within each of these objects according to the invention, preferably with only two output terminals. To ensure the parallel electrical connections of two adjacent cells in the stack, electrical insulation between them is of course ensured. List of cited references

[0109] [1]: D. Martin et al, “Development ofGaSb Photoreceiver Arrays for Solar Thermophotovoltaic Systems,” Journal of Solar Energy Engineering 129, 283 (2007).

[0110] [2]: M. Ahmed et al, “Quantum Cascade Structures for Efficient Thermo- Photovoltaic Energy Conversion », 2012 Photonics Global Conférence (PGC). [OUI] [3]: "PbSnSe / PbSrSe quantum well materials for thermophotovoltaic devices AIP Advances ” 9, 035303 (2019.)

[0112] [4]: G. Marschick, « High-responsivity operation of quantum cascade detectors at 9 pm», Vol. 30, No. 22 / 24 Oct 2022 / Optics Express 40188.

[0113] [5]: https: / / physicsworld.com / a / sunny-superpower-solar-cells-close-in-on-50- efficiency /

[0114] [6]: « Hot Solar Cells By converting heat tofocused beams oflight, a new solar device could create cheap and continuons power», 2017, MIT Technology review: https: / / www.technologyreview.com / technology / hot-solar-cells /

[0115] [7]: Charlie Gréboval et al., “Mercury Chalcogenide Quantum Dots: Material Perspective for Device Intégration1' Chem. Rev. 2021, 121, 7, 3627-3700.

[0116] [8] Han Song, Y “Improving the Efficiency of Quantum Dot Sensitized Solar Cells beyond 15% via Secondary Déposition” by in the Journal of American Chemical Society 2021, 143,4790-4800.

[0117] [9] “Infrared Organic Photovoltaic: A Review Article”, Research Journal of Engineering and Technology • August 2017.

[10] Luyao Lu, Tao Xu, Wei Chen, Erik S. Landry, and Luping Yu “Temary blendpolymer solar cells with enhanced power conversion efficiency”'. Nature Photonics 17 August 2014.

Claims

Demands

1. Thermo-photovoltaic plate comprising at least two thermo-photovoltaic structures stacked one on top of the other and electrically connected in series and / or in parallel, (10) and each comprising: - an alternating stack of thermo-photovoltaic cells (1; 1.1, 1.2, 1.3) and output electrodes so as to connect the cells in series and / or in electrical parallel; - at least one coating (12) of a material, called a radiative material, suitable for dissipating heat from the external environment by radiative cooling, arranged on at least one of the end faces of the stack, so that the infrared radiation emitted by the black body of the coating is converted by the cells into electricity.

2. Thermo-photovoltaic plate according to claim 1, each thermo-photovoltaic cell being made of organic and / or inorganic semiconductor materials.

3. Thermo-photovoltaic plate according to claim 2, at least one of the thermo-photovoltaic cells being made up of two lower (3) and upper (6) electrodes, arranged on either side of at least one stack of three successive thin layers forming a quantum well following: - a layer based on a wide bandgap semiconductor material doped with P-type donors; - a layer based on a narrow bandgap semiconductor material doped with P-type donors; - a layer based on a wide bandgap semiconductor material doped with N-type acceptors.

4. Thermo-photovoltaic plate according to claim 2, at least one of the thermo-photovoltaic cells being made up of two lower (5) and upper (6) electrodes, arranged on either side of at least one stack of three successive thin layers forming a quantum well following: - a layer based on a wide bandgap semiconductor material doped with P-type donors; - a layer based on a low band gap semiconductor material doped with N-type acceptors; - a layer based on a wide band gap semiconductor material doped with N-type acceptors.

5. Thermo-photovoltaic plate according to claim 3 or 4, the wide band gap semiconductor material doped with P-type donors or doped with N-type acceptors, being an indium (In) and gallium (Ga) based alloy, preferably the Ino.7Gao.3As alloy.

6. Thermo-photovoltaic plate according to claim 5, the Ino.7Gao.3As alloy layer having a thickness between 300 and 2000

7. nm. Thermo-photovoltaic plate according to any one of claims 3 to 6, the layer based on low band gap semiconductor material doped by P-type donors or N-type acceptors being an AlAso.8Sbo.2 alloy layer preferably having a thickness between 28 and 80 nm.

8. Thermo-photovoltaic plate according to any one of claims 3 to 7, the at least one thermo-photovoltaic cell comprising several quantum wells stacked one on top of the other forming a quantum cascade.

9. Thermo-photovoltaic plate according to any one of the preceding claims, the thermo-photovoltaic cells being configured to absorb infrared wavelengths between 5 and 50 pm.

10. Thermo-photovoltaic plate according to any one of the preceding claims, each thermo-photovoltaic structure being configured to produce electric currents between 15 and 600A per m2.

11. Thermo-photovoltaic plate according to any one of the preceding claims, the cells in the stack absorbing the shorter wavelengths being arranged closest to the radiative material coating, while the cell(s) furthest away absorb higher wavelengths.

12. Thermo-photovoltaic plate according to any one of the preceding claims, the radiative material coating being made of thermally conductive material, preferably aluminum.

13. Thermo-photovoltaic plate according to any one of the preceding claims, the radiative material coating being of planar shape.

14. Thermo-photovoltaic plate according to the preceding claim, the radiative material being in contact with heat dissipation fins which extend into the external environment.

15. Thermo-photovoltaic plate according to any one of the preceding claims, the radiative material being coated with a thermal protection film on its outer face, opposite that arranged on the stack of thermo-photovoltaic cells, said thermal protection film being adapted to reflect thermal radiation in the infrared range.

16. Thermo-photovoltaic plate according to any one of claims 1 to 14, the face of the thermo-photovoltaic cell stack furthest from the radiative material being coated with a thermal protection film adapted to reflect thermal radiation in the infrared range.

17. Thermo-photovoltaic plate according to one of claims 15 or 16, the thermal protection film being a Bragg mirror.

18. Thermo-photovoltaic plate according to any one of the preceding claims, comprising one or more uprights of thermally conductive material passing through the thermo-photovoltaic structures so as to constitute thermal bridges between the radiative material coating(s) at at least one end of the stack of structures and the radiative material(s) within the stacked structures.

19. Thermo-photovoltaic module comprising at least two thermo-photovoltaic plates according to one of the preceding claims, spaced apart from each other by a space suitable for circulating a heat transfer fluid.

20. Use of a thermo-photovoltaic module according to claim 19 by immersion in an external surrounding medium, so that its fluid such as water from an aquatic environment, or ambient air, circulates by natural or forced convection within the module.

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