A two-terminal perovskite / silicon tandem solar cell and its preparation method

Abstract

The present invention discloses a two-terminal perovskite-silicon tandem cell and a preparation method thereof, which are applied to the technical field of perovskite solar cells. The two-terminal perovskite-silicon tandem cell includes a tandem cell sheet, and the tandem cell sheet includes a perovskite cell structure for absorbing visible light and a silicon cell structure for absorbing near-infrared light. A near-infrared light conversion layer is provided on the light-incident side surface of the two-terminal perovskite-silicon tandem cell, and the near-infrared light conversion layer is a down-conversion thin film. By converting the short wave in sunlight into a long wave through the near-infrared light conversion layer, the problem of current mismatch caused by the two-terminal perovskite-silicon tandem cell under the illumination condition with a relatively high proportion of visible light is solved, so that the two-terminal perovskite-silicon tandem cell has high performance.

Description

Technical Field

[0001] The present invention relates to the technical field of perovskite solar cells, and in particular to a two-terminal perovskite / silicon tandem cell and a method for preparing the two-terminal perovskite / silicon tandem cell. Background Art

[0002] The two-terminal perovskite / silicon tandem cell uses a perovskite cell as the top cell to absorb visible light and a silicon cell as the bottom cell to absorb near-infrared light. This tandem cell is a series structure, and the current is determined by the lowest value of the currents of all sub-cells. In order to achieve current matching and thus maximize the conversion efficiency, a reasonable absorption spectrum distribution needs to be carried out for the sub-cells. Since the bandgap of the silicon cell is determined, in order to maximize the utilization of standard AM1.5 sunlight, it is necessary to control the bandgap of the perovskite bottom cell within the range of 1.68 eV to 1.72 eV, and at the same time, it is also necessary to optimize the thickness of each layer to achieve current matching.

[0003] However, the optimized structures of the above two-terminal perovskite / silicon tandem cells (including the bandgap of the perovskite and the thickness of the perovskite) are all based on standard AM1.5 sunlight. AM refers to the air mass, and AM1.5 refers to the light incident on the Earth's surface when the air mass is 1.5. When the air mass is different, such as different latitudes, weather, and climate, the solar spectrum will change compared with the standard AM1.5 sunlight. There is literature indicating that the proportion of short waves in the solar spectrum at sunrise is significantly lower than that at noon. At this time, the two-terminal perovskite / silicon tandem cell optimized based on standard AM1.5 sunlight will no longer be the optimal structure, and it is necessary to readjust the bandgap, thickness, and even the tandem structure of the perovskite. That is to say, according to the differences in different regions and times, the solar spectrum will be different. Or when the two-terminal perovskite / silicon tandem cell is indoors, the proportion of visible light in the indoor light source is higher than that of outdoor sunlight, which will cause the current generated by the silicon bottom cell to be smaller. Therefore, when the two-terminal perovskite / silicon tandem cell optimized based on AM1.5 is under non-AM1.5 illumination, the cell will have current mismatch and low efficiency, which is not conducive to the future standardization production and large-scale commercialization of the two-terminal perovskite / silicon tandem cell.

[0004] Therefore, how to provide a two-terminal perovskite / silicon tandem cell that can also have high performance under non-standard AM1.5 sunlight conditions is an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0005] The object of the present invention is to provide a two-terminal perovskite / silicon tandem cell which can still have high performance under non-AM1.5 standard sunlight conditions; another object of the present invention is to provide a preparation method of a two-terminal perovskite / silicon tandem cell, and the prepared two-terminal perovskite / silicon tandem cell can still have high performance under non-AM1.5 standard sunlight conditions.

[0006] To solve the above technical problems, the present invention provides a two-terminal perovskite / silicon tandem cell, comprising a perovskite / silicon tandem cell and a near-infrared light conversion layer;

[0007] The perovskite / silicon tandem cell comprises tandem cell sheets, and the tandem cell sheets comprise a perovskite cell structure for absorbing visible light and a silicon cell structure for absorbing near-infrared light;

[0008] The near-infrared light conversion layer is disposed on the light incident side surface of the perovskite / silicon tandem cell, and the near-infrared light conversion layer is a down-conversion thin film.

[0009] Optionally, the perovskite / silicon tandem cell comprises a backplane and a transparent cover plate which are oppositely arranged, the tandem cell sheets are encapsulated between the backplane and the transparent cover plate through encapsulation materials, and the near-infrared light conversion layer is disposed on the surface of the transparent cover plate facing away from the backplane.

[0010] Optionally, the near-infrared light conversion layer is detachably connected to the surface of the transparent cover plate facing away from the backplane.

[0011] Optionally, the near-infrared light conversion layer comprises a polymer matrix and near-infrared luminescent materials dispersed in the polymer matrix; the near-infrared luminescent materials are down-conversion luminescent materials.

[0012] Optionally, the near-infrared luminescent materials include any one or combination of the following:

[0013] Near-infrared quantum dot materials, near-infrared phosphor materials.

[0014] Optionally, the absorption peak of the infrared luminescent materials is between 300 nm and 800 nm, and the emission peak is between 800 nm and 1100 nm.

[0015] Optionally, the polymer matrix is at least one of the following:

[0016] Polyolefin elastomer, polymethyl methacrylate, polyvinylpyrrolidone, silicone, acrylic resin.

[0017] The present invention also provides a preparation method of a two-terminal perovskite / silicon tandem cell, comprising:

[0018] Preparing a near-infrared light conversion layer; the near-infrared light conversion layer is a down-conversion thin film;

[0019] Fabricate a perovskite / silicon tandem cell; the perovskite / silicon tandem cell includes a tandem cell sheet, and the tandem cell sheet includes a perovskite cell structure for absorbing visible light and a silicon cell structure for absorbing near-infrared light;

[0020] Dispose the near-infrared light conversion layer on the light incident side surface of the perovskite / silicon tandem cell to fabricate the two-terminal perovskite / silicon tandem cell.

[0021] Optionally, fabricating the near-infrared light conversion layer includes:

[0022] Fabricate a near-infrared luminescent material; the near-infrared luminescent material is a down-conversion luminescent material;

[0023] Add the near-infrared luminescent material into a polymer melt to form a wet film;

[0024] Cure the wet film to fabricate the near-infrared light conversion layer.

[0025] Optionally, fabricating the perovskite / silicon tandem cell includes:

[0026] Dispose amorphous silicon layers on two opposite side surfaces of an n-type silicon substrate;

[0027] Dispose a P-type amorphous silicon layer on the surface of one side of the amorphous silicon layer, and dispose an N-type amorphous silicon layer on the surface of the other side of the amorphous silicon layer;

[0028] Dispose conductive layers on both the surface of the P-type amorphous silicon layer and the surface of the N-type amorphous silicon layer;

[0029] Dispose a hole transport layer on the conductive layer disposed on one side of the P-type amorphous silicon layer;

[0030] Dispose a perovskite light absorption layer, an electron layer transport layer and an electrode in sequence along the thickness direction on the surface of the hole transport layer to fabricate the tandem cell sheet;

[0031] Encapsulate the tandem cell sheet between a backplane and a transparent cover plate through an encapsulating material to fabricate the perovskite / silicon tandem cell.

[0032] A two-terminal perovskite / silicon tandem cell provided by the present invention includes a perovskite / silicon tandem cell and a near-infrared light conversion layer; the perovskite / silicon tandem cell includes a tandem cell sheet, and the tandem cell sheet includes a perovskite cell structure for absorbing visible light and a silicon cell structure for absorbing near-infrared light; a near-infrared light conversion layer is disposed on the light incident side surface of the perovskite / silicon tandem cell, and the near-infrared light conversion layer is a down-conversion thin film.

[0033] By setting a near-infrared light conversion layer, the short wave in sunlight can be converted into long wave, corresponding to the absorption of the perovskite top cell and the absorption of the crystalline silicon bottom cell respectively, so as to solve the current mismatch problem caused by the two-terminal perovskite / crystalline silicon tandem cell under the illumination condition with a relatively high proportion of visible light, and make the two-terminal perovskite / crystalline silicon tandem cell have high performance.

[0034] The present invention also provides a preparation method of a two-terminal perovskite / crystalline silicon tandem cell, which also has the above beneficial effects and will not be elaborated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0036] Figure 1 It is a schematic structural diagram of a two-terminal perovskite / crystalline silicon tandem cell provided by an embodiment of the present invention;

[0037] Figure 2 It is a process flow chart of a preparation method of a two-terminal perovskite / crystalline silicon tandem cell provided by an embodiment of the present invention;

[0038] Figure 3 It is a process flow chart of a preparation method of a perovskite / crystalline silicon tandem cell provided by an embodiment of the present invention;

[0039] Figure 4 It is an emission spectrum diagram of a CuInS2 / ZnS quantum dot light conversion film prepared based on different reaction times;

[0040] Figure 5 It is a luminescence spectrum diagram of the near-infrared light conversion layer;

[0041] Figure 6 It is a change diagram of the current of the two-terminal perovskite / crystalline silicon tandem cell optimized based on the AM1.5 standard sunlight in Comparative Example 1 with the change of the test spectrum;

[0042] Figure 7 It is a change diagram of the current of the two-terminal perovskite / crystalline silicon tandem cell containing a near-infrared light conversion layer in Example 1 with the change of the test spectrum.

[0043] In the figure: 1. Perovskite / crystalline silicon tandem cell, 11. Tandem cell sheet, 12. Backplane, 13. Transparent cover plate, 14. Encapsulation material, 2. Near-infrared light conversion layer. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0044] The core of the present invention is to provide a two-terminal perovskite / silicon tandem cell. In the prior art, the optimized structures of two-terminal perovskite / silicon tandem cells are all based on the AM1.5 standard sunlight. When a two-terminal perovskite / silicon tandem cell optimized based on AM1.5 is under non-AM1.5 illumination, the cell will exhibit current mismatch and low efficiency, which is not conducive to the future standardized production and large-scale commercialization of two-terminal perovskite / silicon tandem cells.

[0045] A two-terminal perovskite / silicon tandem cell provided by the present invention includes a perovskite / silicon tandem cell and a near-infrared light conversion layer; the perovskite / silicon tandem cell includes a tandem cell sheet, and the tandem cell sheet includes a perovskite cell structure for absorbing visible light and a silicon cell structure for absorbing near-infrared light; a near-infrared light conversion layer is disposed on the light-incident side surface of the perovskite / silicon tandem cell, and the near-infrared light conversion layer is a down-conversion thin film.

[0046] By providing the near-infrared light conversion layer, short waves in sunlight can be converted into long waves, corresponding to the absorption of the perovskite top cell and the absorption of the silicon bottom cell respectively, so as to solve the current mismatch problem caused by the two-terminal perovskite / silicon tandem cell under illumination conditions with a relatively high proportion of visible light, and enable the two-terminal perovskite / silicon tandem cell to have high performance.

[0047] To enable those skilled in the art to better understand the solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0048] Please refer to Figure 1 , Figure 1 which is a schematic structural diagram of a two-terminal perovskite / silicon tandem cell provided by an embodiment of the present invention.

[0049] Referring to Figure 1 ,in an embodiment of the present invention, the two-terminal perovskite / silicon tandem cell includes a perovskite / silicon tandem cell 1 and a near-infrared light conversion layer 2; the perovskite / silicon tandem cell 1 includes a tandem cell sheet 11, and the tandem cell sheet 11 includes a perovskite cell structure for absorbing visible light and a silicon cell structure for absorbing near-infrared light. In this embodiment, the perovskite cell structure and the silicon cell structure are usually current-matched based on the AM1.5 standard sunlight; the near-infrared light conversion layer 2 is disposed on the light-incident side surface of the perovskite / silicon tandem cell 1, and the near-infrared light conversion layer 2 is a down-conversion thin film.

[0050] The above-mentioned perovskite-silicon tandem cell 1 is a conventional tandem solar cell module. The core of the perovskite-silicon tandem cell 1 is the tandem cell chip 11, which includes a perovskite cell structure for absorbing visible light and a silicon cell structure for absorbing near-infrared light. Among them, the perovskite cell structure usually serves as the top cell of the tandem cell chip 11, while the silicon cell structure serves as the bottom cell of the tandem cell chip 11 to absorb light of corresponding wavelengths. For the specific structure of the tandem cell chip 11, reference can be made to the prior art and will not be elaborated here. In this embodiment, the perovskite cell structure and the silicon cell structure of the tandem cell chip 11 are usually current-matched based on the AM1.5 standard sunlight, that is, under the irradiation of the AM1.5 standard sunlight, the perovskite cell structure and the silicon cell structure can generate the maximum current, and at this time, the tandem cell chip 11 has the maximum power generation efficiency. Of course, in this embodiment, the current matching of the perovskite cell structure and the silicon cell structure can also be carried out based on other lighting conditions. Here, the specific lighting conditions are not specifically limited, as long as the external light can be as close as possible to this lighting condition after passing through the near-infrared light conversion layer 2 introduced later to maintain a high power generation efficiency of the two-terminal perovskite-silicon tandem cell.

[0051] Specifically, in this embodiment, the perovskite-silicon tandem cell 1 includes a backplane 12 and a transparent cover plate 13 arranged oppositely. The tandem cell chip 11 is encapsulated between the backplane 12 and the transparent cover plate 13 through a packaging material 14, and the near-infrared light conversion layer 2 is arranged on the surface of the transparent cover plate 13 facing away from the backplane 12.

[0052] The above-mentioned backplane 12 can be a transparent backplane 12 or a non-transparent backplane 12. For the perovskite-silicon tandem cell 1, a double-glass packaging structure is usually selected for packaging, so the backplane 12 is usually a transparent backplane 12, which is usually glass. Correspondingly, the above-mentioned transparent cover plate 13 usually also selects glass as the front cover plate. Of course, in this embodiment, the specific materials of the backplane 12 and the transparent cover plate 13 are not specifically limited and depend on the specific situation. The above-mentioned packaging material 14 is usually a polyolefin elastomer and butyl rubber, which is used to encapsulate the above-mentioned tandem cell chip 11 between the backplane 12 and the transparent cover plate 13. At this time, for the perovskite-silicon tandem cell 1, the surface of the transparent cover plate 13 facing away from the backplane 12 is the light-incident surface, so the near-infrared light conversion layer 2 is arranged on this surface.

[0053] As can be seen from the above structure, the perovskite-silicon tandem cell 1 in this embodiment can be a perovskite-silicon tandem cell 1 that performs current matching with the most common AM1.5 standard sunlight as the standard. This structure is very conducive to the standardized production and large-scale commercialization of the two-terminal perovskite-silicon tandem cell 1. And the above-mentioned near-infrared light conversion layer 2 is to make it more suitable for the illumination environment where the proportion of visible light is higher than that of the AM1.5 standard sunlight on the basis of this perovskite-silicon tandem cell 1.

[0054] The above-mentioned near-infrared light conversion layer 2 is disposed on the light-incident side surface of the perovskite-silicon tandem cell 1, that is, the external natural light will first enter the near-infrared light conversion layer 2 and then enter the perovskite-silicon tandem cell 1. When the natural light enters the near-infrared light conversion layer 2, the near-infrared light conversion layer 2 will redistribute the proportion of light of each wavelength. Since the near-infrared light conversion layer 2 in this embodiment is a down-conversion thin film, it can absorb short-wavelength light and emit long-wavelength light, that is, the near-infrared light conversion layer 2 can convert visible light into near-infrared light, thereby adjusting the proportion of light of different wavelengths in the incident light. The two-terminal perovskite-silicon tandem cell in this embodiment mainly operates in an illumination environment where the proportion of visible light is higher than that of the AM1.5 standard sunlight. In this illumination environment, when the natural light passes through the near-infrared light conversion layer 2 and propagates to the perovskite-silicon tandem cell 1, the light received by the perovskite-silicon tandem cell 1 is closer to the AM1.5 standard sunlight compared to the current illumination environment. In other words, the near-infrared light conversion layer 2 can adjust the above illumination environment to be closer to the illumination environment of the AM1.5 standard sunlight, so that the perovskite-silicon tandem cell 1 has a high working efficiency.

[0055] Specifically, in this embodiment, the near-infrared light conversion layer 2 includes a polymer matrix and a near-infrared luminescent material dispersed in the polymer matrix; the near-infrared luminescent material is a down-conversion luminescent material to form a down-conversion thin film. The above-mentioned near-infrared luminescent material includes any one or combination of the following: near-infrared quantum dot materials, near-infrared phosphor materials. Correspondingly, in this embodiment, the polymer matrix is at least one of the following: polyolefin elastomer, polymethyl methacrylate, polyvinylpyrrolidone, silicone, acrylic resin. Of course, in this embodiment, the structure or components of the near-infrared luminescent material and the specific components of the polymer matrix are not specifically limited, and the specific ones can refer to the prior art.

[0056] In order to ensure that the perovskite-silicon tandem cell 1 has a high efficiency during operation, in this embodiment, the absorption peak of the infrared luminescent material is usually between 300 nm and 800 nm, and the emission peak is usually between 800 nm and 1100 nm. That is, the above-mentioned near-infrared light conversion layer 2 can adjust the proportion of light with wavelengths between 300 nm and 800 nm and light with wavelengths between 800 nm and 1100 nm.

[0057] It should be noted that, depending on the thickness of the near-infrared light conversion layer 2 or the materials used, the amount of short-wavelength light absorbed and the amount of long-wavelength light emitted will also vary. Therefore, the ratio between the short-wavelength light and the long-wavelength light it adjusts will also be different. However, it is obvious that the near-infrared light conversion layer 2 in this embodiment will not absorb all the short-wavelength light, for example, all the light with wavelengths between 300 nm and 800 nm. Obviously, compared with the perovskite-silicon tandem cell 1, the near-infrared light conversion layer 2 is easier to fabricate. Therefore, the near-infrared light conversion layer 2 can be customized according to the actual situation, so that the two-terminal perovskite-silicon tandem cell provided in this embodiment can better adapt to the light environment in different latitudes and scenarios.

[0058] In this embodiment, the near-infrared light conversion layer 2 is usually detachably connected to the surface of the transparent cover plate 13 on the side facing away from the back plate 12. The detachable connection facilitates the replacement of the near-infrared light conversion layer 2, so that the two-terminal perovskite-silicon tandem cell provided in this embodiment has a broader applicable environment. Specifically, the above-mentioned near-infrared light conversion layer 2 can be pasted on the surface of the transparent cover plate 13 on the side facing away from the back plate 12, which is convenient for the installation and replacement of the near-infrared light conversion layer 2. In an actual scenario, when the usage environment of the two-terminal perovskite-silicon tandem cell is determined, it is only necessary to paste the corresponding near-infrared conversion layer on the surface of the perovskite-silicon tandem cell 1 that has already left the factory.

[0059] For a two-terminal perovskite-silicon tandem cell provided in this embodiment, by setting the near-infrared light conversion layer 2, the short waves in sunlight can be converted into long waves, corresponding to the absorption of the perovskite top cell and the absorption of the silicon bottom cell respectively, so as to solve the problem of current mismatch caused by the two-terminal perovskite-silicon tandem cell optimized based on the AM1.5 standard sunlight under the illumination with a visible light ratio higher than that of the AM1.5 standard sunlight, so that the two-terminal perovskite-silicon tandem cell can still have high performance under non-AM1.5 standard sunlight conditions.

[0060] Next, a preparation method of a two-terminal perovskite-silicon tandem cell provided in an embodiment of the present invention will be introduced. The preparation method of a two-terminal perovskite-silicon tandem cell described below can be correspondingly referred to the perovskite thin film described above.

[0061] Please refer to Figure 2 , Figure 2 which is a process flow chart of a preparation method of a two-terminal perovskite-silicon tandem cell provided in an embodiment of the present invention.

[0062] See Figure 2 In an embodiment of the present invention, the preparation method of the two-terminal perovskite-silicon tandem cell includes:

[0063] S101: Prepare a near-infrared light conversion layer.

[0064] In an embodiment of the present invention, the near-infrared light conversion layer 2 is a down-conversion thin film. In this embodiment, according to the different structures of the near-infrared conversion layer, it can be prepared by corresponding methods. Specifically, this step generally includes: preparing a near-infrared luminescent material; the near-infrared luminescent material is a down-conversion luminescent material; adding the near-infrared luminescent material to a polymer melt to form a wet film; and curing the wet film to form the near-infrared light conversion layer 2.

[0065] The above-mentioned near-infrared luminescent material can specifically be a near-infrared quantum dot material or a near-infrared phosphor material. In this embodiment, corresponding methods will be selected for preparation according to the different types of near-infrared luminescent materials. Then, in this step, the near-infrared luminescent material will be added to the polymer melt in a viscous flow state for dispersion, and then cooled to form a wet film. After that, the wet film will be cured to evaporate the solvent therein to form the near-infrared light conversion layer 2.

[0066] S102: Prepare a perovskite-silicon tandem cell.

[0067] In an embodiment of the present invention, the perovskite-silicon tandem cell 1 includes a tandem cell sheet 11, the tandem cell sheet 11 includes a perovskite cell structure for absorbing visible light and a silicon cell structure for absorbing near-infrared light, and the perovskite cell structure and the silicon cell structure are current-matched based on the AM1.5 standard sunlight. The structure of the perovskite-silicon tandem cell 1 has been introduced in detail in the above-mentioned invention embodiments, and the specific content of this step is shown in the following invention embodiments.

[0068] It should be noted that there is no clear sequence between the above S101 and S102, and they can be executed in any order or simultaneously.

[0069] S103: Dispose the near-infrared light conversion layer on the light-incident side surface of the perovskite-silicon tandem cell to form a two-terminal perovskite-silicon tandem cell.

[0070] In this step, specifically, the near-infrared light conversion layer 2 can be attached to the light-incident side surface of the perovskite-silicon tandem cell 1 to form the above two-terminal perovskite-silicon tandem cell.

[0071] A method for preparing a two-terminal perovskite / silicon tandem solar cell provided by an embodiment of the present invention can convert short-wavelength light in sunlight into long-wavelength light by setting a near-infrared light conversion layer 2, corresponding to the absorption of the perovskite top cell and the absorption of the silicon bottom cell respectively, so as to solve the current mismatch problem of the two-terminal perovskite / silicon tandem solar cell optimized based on AM1.5 standard sunlight under illumination with a higher proportion of visible light than AM1.5 standard sunlight, enabling the two-terminal perovskite / silicon tandem solar cell to still have high performance under non-AM1.5 standard sunlight conditions.

[0072] Next, a method for preparing a perovskite / silicon tandem solar cell 1 provided by an embodiment of the present invention will be introduced.

[0073] Please refer to Figure 3 , Figure 3 which is a process flow chart of a method for preparing a perovskite / silicon tandem solar cell provided by an embodiment of the present invention.

[0074] It should be noted that the following method for preparing the perovskite / silicon tandem solar cell 1 corresponds to the specific content of the above S102. Refer to Figure 3 , in the embodiment of the present invention, the method for preparing the perovskite / silicon tandem solar cell 1 includes:

[0075] S201: Set amorphous silicon layers on both opposite surfaces of the n-type silicon substrate.

[0076] In this step, an n-type silicon substrate will be specifically selected, and then a layer of amorphous silicon will be set on each of the two opposite surfaces of the n-type silicon substrate through processes such as plasma-enhanced chemical vapor deposition, for a total of two layers of amorphous silicon.

[0077] S202: Set a P-type amorphous silicon layer on the surface of one amorphous silicon layer and an N-type amorphous silicon layer on the surface of the other amorphous silicon layer.

[0078] In this step, a P-type amorphous silicon layer will be set on the surface of one of the two amorphous silicon layers, and an N-type amorphous silicon layer will be set on the surface of the other amorphous silicon layer.

[0079] S203: Set conductive layers on both the surface of the P-type amorphous silicon layer and the surface of the N-type amorphous silicon layer.

[0080] In this step, conductive layers are set on the surface of the P-type amorphous silicon layer and the surface of the N-type amorphous silicon layer respectively, for a total of two conductive layers, forming a silicon solar cell structure. The conductive layer can be an ITO thin film or other conductive thin films, and no specific limitation is made here.

[0081] S204: Set a hole transport layer on the conductive layer surface provided on the side of the P-type amorphous silicon layer.

[0082] In this step, a hole transport layer can be specifically formed on the surface of the conductive layer through processes such as magnetron sputtering, so as to form a perovskite battery structure subsequently.

[0083] S205: A perovskite light-absorbing layer, an electron transport layer, and an electrode are sequentially arranged on the surface of the hole transport layer in the thickness direction to fabricate a stacked cell.

[0084] In this step, the above-mentioned perovskite light-absorbing layer, electron transport layer, and electrode can be sequentially arranged by methods such as deposition and / or vacuum evaporation to form a perovskite battery structure. The preparation processes of the above-mentioned respective film layers need to correspond to their components, and the specific content of each process needs to be determined according to the actual situation and will not be specifically limited here.

[0085] After this step, an antireflection layer and / or a passivation layer can be further arranged on the stacked cell 11 to improve the performance of the stacked cell 11.

[0086] S206: The stacked cell is encapsulated between a backplane and a transparent cover plate through a packaging material to fabricate a perovskite-silicon stacked cell.

[0087] In this step, the stacked cell 11 needs to be encapsulated through a packaging material 14, a backplane 12, and a transparent cover plate 13 to fabricate a packaged perovskite-silicon stacked cell 1.

[0088] Example 1

[0089] This example specifically provides a preparation method of a near-infrared light conversion film based on CuInS2 / ZnS quantum dots for fabricating a two-terminal perovskite-silicon stacked cell.

[0090] The first step: Prepare quantum dots: The preparation method of the quantum dots can refer to the reported literature (Doctor-bladedeposition of quantum dots ontostandard window glass for low-loss large-arealuminescent solar concentrators, Nature Energy, 1, 16157 (2016)). The specific steps are as follows:

[0091] Preparation of zinc precursor: Take 440 mg of Zn(Ac)2·2H2O and add it to 3 mL of OA (oleic acid) solution and 2 mL of ODE (octadecene) solution, heat to 150 °C and maintain for at least 30 minutes.

[0092] Preparation of CuInS2 quantum dots: 76.2 mg of CuI, 247.8 mg of InI3 and 35.2 mg of S were added to a 50 mL three-necked flask. Then, 10 mL of ODE, 3 mL of DTT (dodecanethiol), 1 mL of OA and 1 mL of OLA (oleylamine) were added successively. The mixture was heated to 100 °C and continuously stirred until all solids were completely dissolved. During the stirring process, vacuum degassing was carried out and maintained for 15 min. At this time, the solution was red to dark red. Under nitrogen protection, the reaction temperature was raised to 220 °C (at a rate of 10 °C per minute) and maintained at this temperature for 0 - 30 minutes to obtain CuInS2 quantum dots with different sizes.

[0093] Preparation of CuInS2 / ZnS quantum dots: 5 mL of zinc precursor solution was added to the above reaction system at 220 °C at a rate of 1 - 2 mL per minute. After the addition, the temperature was adjusted to 250 °C. After reacting for 45 minutes, the heat source was carefully removed and allowed to cool naturally to room temperature.

[0094] Purification of CuInS2 / ZnS quantum dots: Four times the volume of ethanol was added to the above-cooled reaction solution. After shaking well, it was centrifuged at 8000 rpm for 5 minutes. After centrifugation, the supernatant was poured off, and the black precipitate was redissolved in 20 mL of toluene. Twice the volume of ethanol was added again, and the above operation was repeated three times.

[0095] Silicone was added to the toluene solution of the prepared CuInS2 / ZnS quantum dots, and the mass ratio of the quantum dots to silicone was 2%. Then, a wet film was prepared by screen printing. After evaporating the solvent and curing by heating at 80 °C for half an hour, a film with a thickness of 0.5 microns was obtained, which was the near-infrared light conversion layer 2.

[0096] Please refer to Figure 4 , Figure 4 For the emission spectra of the CuInS2 / ZnS quantum dot light conversion films prepared based on different reaction times. By changing the nucleation reaction time from 0 minutes to 10 minutes, 20 minutes, 30 minutes, near-infrared light conversion layers 2 with emission peaks at 833 nm, 876 nm, 921 nm and 978 nm can be obtained, and their luminous efficiencies are 92%, 91%, 89% and 85% respectively. According to the characteristics of the quantum dots, the reaction conditions can be changed to change the size of the quantum dots, and then quantum dot materials with different wavelengths can be obtained. Among them, this example can be based on the near-infrared light conversion film prepared from quantum dots with a peak of 978 nm.

[0097] Second step, preparation of perovskite silicon tandem battery 1:

[0098] On the cleaned and texturized n-type monocrystalline silicon (C-Si), a layer of amorphous silicon is deposited on each by plasma enhanced chemical vapor deposition process, with thicknesses of 10 nm (i-a-Si) and 8 nm (i-a-Si) respectively;

[0099] On the 10-nm i-a-Si, a 15-nm layer of p-type amorphous silicon (P-a-Si) is deposited, and on the 8-nm i-a-Si, a 10-nm layer of n-type amorphous silicon (N-a-Si) is deposited;

[0100] On the P-a-Si and -N-a-Si, two layers of indium tin oxide (ITO) are respectively prepared by magnetron sputtering, with both thicknesses of 25 nm;

[0101] On the side of the n-type amorphous silicon (N-a-Si) ITO, a layer of nickel oxide (NiO x ) is sputtered as a hole transport layer, with a thickness of 15 nm.

[0102] On the NiO x A perovskite light-absorbing layer is deposited. The deposition process of the perovskite light-absorbing layer is as follows: Weigh 2.8 mmol of cesium iodide CsI, 11.2 mmol of formamidinium iodide FAI, 0.07 mmol of phenethylammonium iodide, 5.6 mmol of lead iodide PbI2, 8.4 mmol of lead bromide PbBr2. Add 8 mL of N,N'-dimethylformamide DMF and 2 mL of dimethyl sulfoxide DMSO to the mixture, stir well to completely dissolve it, and filter to form a precursor solution. A perovskite thin film of about 400 nm is prepared by the solution method as the perovskite light-absorbing layer.

[0103] On the perovskite layer, about 25 nm of fullerene (C60) and about 8 nm of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) are deposited by vacuum evaporation as an electron transport layer. Then, 800 nm of silver is deposited on the electron transport layer by vacuum evaporation, and a mask template is needed for patterning. Then, 85 nm of magnesium fluoride is evaporated at the position where the perovskite is coated but the silver electrode is not evaporated as an antireflection layer, and the stacked cell 11 is obtained.

[0104] The laminated cell 11 can adopt the same double-glass encapsulation method as that of crystalline silicon cells. Among them, the backsheet 12 and the transparent cover plate 13 are the glasses for double-glass encapsulation, the encapsulation material 14 is polyolefin elastomer and butyl rubber, the backsheet 12 and the transparent cover plate 13 sandwich the laminated cell in the middle, and the encapsulation material 14 is used to bond the two glasses. The backsheet 12 can also select other opaque base materials. That is, the perovskite / crystalline silicon laminated cell 1 is obtained. In the perovskite / crystalline silicon laminated cell 1, factors such as the band gap and thickness of the laminated cell 11 are all optimized based on the AM1.5 standard light test. Through testing, the current densities of the top cell and the sub-cell are 19.2 mA / cm -2 and 19.4 mA / cm -2 , indicating that the current matching of the cell is achieved under the AM1.5 standard light.

[0105] Step 3: Place the obtained near-infrared light conversion layer 2 flat on the light-incident surface of the encapsulated perovskite / crystalline silicon laminated cell 1, that is, place it on the top of the front cover plate, and the above-mentioned two-terminal perovskite / crystalline silicon laminated cell with the near-infrared light conversion layer 2 is obtained.

[0106] Example 2

[0107] This example specifically provides a preparation method of a two-terminal perovskite / crystalline silicon laminated cell based on a near-infrared phosphor-based near-infrared light conversion film.

[0108] Step 1: First, prepare the near-infrared phosphor, and the specific steps are as follows:

[0109] Weigh Lu2O3, Sc2O3, H3BO3, Cr2O3, Yb2O3 according to the molar ratio of 20:80:255:2:5, mix them evenly by ball milling, then calcine at 1200 °C, and then obtain the near-infrared phosphor after crushing, sieving, and washing.

[0110] Add the prepared Lu 0.2 Sc 0.8 BO3, 2% Cr 3+ , 5% Yb 3+ directly into the n-hexane solvent of silicone, and disperse it by ultrasonic wave. The mass ratio of the phosphor to silicone is 1%; then prepare a wet film by screen printing, evaporate the solvent, and cure it at 80 °C for half an hour. The thickness of the obtained film is 1 micron, which is the near-infrared light conversion layer 2.

[0111] Please refer to Figure 5 , Figure 5 which is the emission spectrum diagram of the near-infrared light conversion layer 2. As Figure 5 shown, similar to the near-infrared light conversion film based on quantum dots, it can also convert visible light into near-infrared light.

[0112] Step 2: Next, prepare a two-terminal stacked cell. The process steps are the same as those in Example 1, specifically as follows: Deposit an amorphous silicon layer on the cleaned and textured n-type monocrystalline silicon (C-Si) by plasma-enhanced chemical vapor deposition. The thicknesses are 10 nm (i-a-Si) and 8 nm (i-a-Si), respectively.

[0113] Deposit a 15-nm P-type amorphous silicon (P-a-Si) layer on the 10-nm i-a-Si, and deposit a 10-nm N-type amorphous silicon (N-a-Si) layer on the 8-nm i-a-Si.

[0114] Prepare two layers of indium tin oxide (ITO) with a thickness of 25 nm each on the P-a-Si and -N-a-Si by magnetron sputtering.

[0115] Sputter a layer of nickel oxide (NiO x ) as a hole transport layer on one side of the ITO, with a thickness of 15 nm.

[0116] Deposit a perovskite light-absorbing layer on the NiO x The deposition process of the perovskite light-absorbing layer is as follows: Weigh 2.8 mmol of cesium iodide CsI, 11.2 mmol of formamidinium iodide FAI, 0.07 mmol of phenethylammonium iodide, 5.6 mmol of lead iodide PbI2, and 8.4 mmol of lead bromide PbBr2. Add 8 mL of N,N'-dimethylformamide DMF and 2 mL of dimethyl sulfoxide DMSO to the mixture, stir well to completely dissolve it, and filter to form a precursor solution. Prepare a perovskite thin film of about 400 nm as the perovskite light-absorbing layer by solution method.

[0117] Deposit about 25 nm of fullerene (C60) and about 8 nm of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) as an electron transport layer on the perovskite layer by vacuum evaporation. Then deposit 800 nm of silver as an electrode on the electron transport layer by vacuum evaporation, and a mask template is required for patterning. Then deposit a layer of 85 nm of magnesium fluoride at the position where the perovskite is coated but the silver electrode is not evaporated as an antireflection layer to obtain the stacked cell sheet 11.

[0118] The laminated cell 11 can adopt the same double-glass encapsulation method as that of crystalline silicon cells. Among them, the backplane 12 and the transparent cover plate 13 are the glasses for double-glass encapsulation, the encapsulation material 14 is polyolefin elastomer and butyl rubber, the backplane 12 and the transparent cover plate 13 sandwich the laminated cell in the middle, and the encapsulation material 14 is used to bond the two glasses. The backplane 12 can also select other opaque substrate materials. That is, the perovskite / crystalline silicon laminated cell 1 is obtained. The factors such as the band gap and thickness of the laminated cell 11 in the perovskite / crystalline silicon laminated cell 1 are all optimized based on the AM1.5 standard light test. Through testing, the current densities of the top cell and the sub-cell are 19.2 mA / cm -2 and 19.4 mA / cm -2 , indicating that the cell achieves current matching under the AM1.5 standard light.

[0119] Step 3: Place the near-infrared light conversion layer 2 prepared based on near-infrared phosphor flatly on the light-incident surface of the encapsulated perovskite / crystalline silicon laminated cell 1, that is, place it on the top of the front cover plate, and the two-terminal perovskite / crystalline silicon laminated cell with the near-infrared light conversion layer 2 of Example 2 is obtained.

[0120] Comparative Example 1

[0121] Based on the above Example 1, the preparation of the near-infrared light conversion layer 2 is not carried out, and the near-infrared light conversion layer 2 is not added to the surface of the encapsulated perovskite / crystalline silicon laminated cell 1, and the two-terminal perovskite / crystalline silicon laminated cell without the near-infrared light conversion layer 2 of Comparative Example 1 is obtained.

[0122] Testing method

[0123] To characterize the current matching of a two-terminal tandem cell, the present invention uses a current-voltage test with a spectrally tunable light source (Spectrometric Characterization of Monolithic Perovskite / Silicon Tandem Solar Cells, Sol. RRL 2023, 7, 2200948). The specific principle is to test the current-voltage curves of the two-terminal tandem cell under different spectra by changing the solar spectrum simulator based on light-emitting diodes. For a two-terminal perovskite / silicon tandem cell 1 optimized for AM1.5, when the spectrum of the test light source is close to AM1.5, the currents of the two sub-cell structures are close, and at this time, the current of the two-terminal tandem cell is the largest. When the proportion of visible light in the test light source increases, that is, the spectrum blue-shifts (by increasing the power of the visible-light-emitting diodes in the solar simulator and decreasing the power of the near-infrared light-emitting diodes), the photocurrent generated by the silicon sub-cell will decrease. Although the photocurrent generated by the perovskite sub-cell will increase, since this is a series cell, the current of the two-terminal tandem cell will ultimately decrease. Therefore, when the spectrum blue-shifts, the current of the silicon sub-cell will limit the current of the device. On the contrary, when the spectrum red-shifts, the current of the perovskite sub-cell will limit the current of the device.

[0124] Please refer to Figure 6 , Figure 6 Figure for the change in the current of the two-terminal perovskite / silicon tandem cell 1 optimized for AM1.5 standard sunlight in Comparative Example 1 with the change in the test spectrum. As can be seen from Figure 6 it, the spectrum corresponding to the maximum current is the AM1.5 standard spectrum. When the test spectrum blue-shifts, the current of the two-terminal perovskite / silicon tandem cell 1 optimized for AM1.5 decreases.

[0125] Please refer to Figure 7 , Figure 7 Figure for the change in the current of the two-terminal perovskite / silicon tandem cell 1 containing the near-infrared light conversion layer 2 in Example 1 with the change in the test spectrum. As can be seen from Figure 7 it, the spectrum corresponding to the maximum current, that is, the matching current of the two sub-cell structures, is blue-shifted compared to the AM1.5 standard spectrum. The only difference from Comparative Example 1 is the addition of a near-infrared light conversion layer 2, and current matching can be achieved under different spectra without changing the perovskite bandgap, film thickness, or structure.

[0126] The present invention tests the performance of the two-terminal perovskite / silicon tandem cells 1 in Comparative Example 1 and Example 1 under non-AM1.5 standard solar spectra. Still control the total power of the multi-channel LED (light-emitting diode) light source simulator to be 1000 W / m 2, the optical power in the wavelength band less than 800 nm is increased by 5%, and the optical power in the wavelength band greater than 800 nm is reduced by 5%. The current of the tandem cell in Comparative Example 1 is reduced to 17.8 mA / cm 2 , and the energy conversion efficiency is 28.9%. The current of the tandem cell in Example 1 is 18.9 mA / cm 2 , 30.1%. This result shows that the two-terminal perovskite-silicon tandem cell 1 containing the near-infrared light conversion layer 2 can significantly improve the efficiency of the two-terminal perovskite-silicon tandem cell 1 under the non-AM1.5 standard solar spectrum (with a large proportion of visible light).

[0127] Next, the performance of the two-terminal perovskite-silicon tandem cells 1 in Comparative Example 1 and Example 2 was tested under the non-AM1.5 standard solar spectrum. The total power of the multi-channel LED light source simulator was still controlled to be 1000 W / m 2 , the optical power in the wavelength band less than 800 nm is increased by 5%, and the optical power in the wavelength band greater than 800 nm is reduced by 5%. The current of the tandem cell in Comparative Example 1 is reduced to 17.8 mA / cm 2 , and the energy conversion efficiency is 28.9%. The current of the tandem cell in Example 1 is 18.4 mA / cm 2 , 29.4%. This result shows that the use of the near-infrared phosphor to prepare the near-infrared light conversion layer 2 can also improve the efficiency of the two-terminal perovskite-silicon tandem cell 1 under the non-AM1.5 standard solar spectrum.

[0128] In this specification, each embodiment is described in a progressive manner. The key point of each embodiment is to illustrate the differences from other embodiments. For the same or similar parts among the embodiments, reference can be made to each other.

[0129] Those skilled in the art can further realize that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be implemented by electronic hardware, computer software, or a combination of the two. To clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described according to functions in the above description. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention.

[0130] The steps of the methods or algorithms described in connection with the embodiments disclosed herein may be implemented directly in hardware, in software modules executed by a processor, or in a combination thereof. The software modules may be placed in a random access memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium well-known in the art.

[0131] Finally, it should also be noted that in this document, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variation thereof is intended to cover non-exclusive inclusion, such that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the phrase "comprising a..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the element.

[0132] The above has introduced in detail a two-terminal perovskite-silicon tandem solar cell and its preparation method provided by the present invention. Specific examples are used herein to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A two-terminal perovskite / silicon tandem solar cell, characterized in that It includes a perovskite-silicon tandem cell and a near-infrared light conversion layer; The perovskite-silicon tandem cell includes tandem cell wafers, and the tandem cell wafers include a perovskite cell structure for absorbing visible light and a silicon cell structure for absorbing near-infrared light; The near-infrared light conversion layer is disposed on the light-incident side surface of the perovskite-silicon tandem cell, and the near-infrared light conversion layer is a down-conversion thin film; The perovskite-silicon tandem cell includes a backplane and a transparent cover plate disposed opposite to each other. The tandem cell wafers are encapsulated between the backplane and the transparent cover plate by encapsulating materials, and the near-infrared light conversion layer is disposed on the surface of the transparent cover plate facing away from the backplane; the near-infrared light conversion layer is detachably connected to the surface of the transparent cover plate facing away from the backplane; The perovskite cell structure and the silicon cell structure are current-matched based on AM1.5 standard sunlight. The near-infrared light conversion layer converts visible light into near-infrared light, adjusts the proportion of light with different wavelengths in the incident light, and makes the light received by the perovskite-silicon tandem cell closer to the illumination environment of AM1.5 standard sunlight compared to the current illumination environment; The absorption peak of the infrared luminescent material is between 300 nm and 800 nm, and the emission peak is between 800 nm and 1100 nm.

2. The two-terminal perovskite / silicon tandem cell according to claim 1, wherein, The near-infrared light conversion layer includes a polymer matrix and a near-infrared luminescent material dispersed in the polymer matrix; the near-infrared luminescent material is a down-conversion luminescent material.

3. The two-terminal perovskite / silicon tandem cell according to claim 2, wherein, The near-infrared luminescent material includes any one or combination of the following: Near-infrared quantum dot materials, near-infrared phosphor materials.

4. The two-terminal perovskite / silicon tandem cell according to claim 2, wherein The polymer matrix is at least one of the following: Polyolefin elastomers, polymethyl methacrylate, polyvinyl pyrrolidone, silicone, acrylic resins.

5. A method for preparing a two-terminal perovskite-silicon tandem solar cell, characterized in that, It includes: Preparing a near-infrared light conversion layer; The near-infrared light conversion layer is a down-conversion thin film; Preparing a perovskite-silicon tandem cell; The perovskite-silicon tandem cell includes tandem cell wafers, and the tandem cell wafers include a perovskite cell structure for absorbing visible light and a silicon cell structure for absorbing near-infrared light; Disposing the near-infrared light conversion layer on the light-incident side surface of the perovskite-silicon tandem cell to make the two-terminal perovskite-silicon tandem cell; The perovskite-silicon tandem cell includes a backplane and a transparent cover plate disposed opposite to each other. The tandem cell wafers are encapsulated between the backplane and the transparent cover plate by encapsulating materials, and the near-infrared light conversion layer is disposed on the surface of the transparent cover plate facing away from the backplane; the near-infrared light conversion layer is detachably connected to the surface of the transparent cover plate facing away from the backplane; The perovskite cell structure and the silicon cell structure are current-matched based on AM1.5 standard sunlight. The near-infrared light conversion layer converts visible light into near-infrared light, adjusts the proportion of light with different wavelengths in the incident light, and makes the light received by the perovskite-silicon tandem cell closer to the illumination environment of AM1.5 standard sunlight compared to the current illumination environment; The absorption peak of the infrared luminescent material is between 300 nm and 800 nm, and the emission peak is between 800 nm and 1100 nm.

6. The method according to claim 5, characterized in that Preparing the near-infrared light conversion layer includes: Preparing a near-infrared luminescent material; the near-infrared luminescent material is a down-conversion luminescent material; Adding the near-infrared luminescent material into a polymer melt and then making a wet film; Curing the wet film to make a near-infrared light conversion layer.

7. The method according to claim 5, wherein Preparing a perovskite silicon heterojunction tandem solar cell includes: Providing amorphous silicon layers on opposite two side surfaces of an n-type silicon substrate; Providing a p-type amorphous silicon layer on the surface of the amorphous silicon layer on one side, and providing an n-type amorphous silicon layer on the surface of the amorphous silicon layer on the other side; Providing conductive layers on the surfaces of the p-type amorphous silicon layer and the n-type amorphous silicon layer; Providing a hole transport layer on the surface of the conductive layer provided on the p-type amorphous silicon layer side; Sequentially providing a perovskite light absorption layer, an electron transport layer and an electrode along the thickness direction on the surface of the hole transport layer to make the tandem solar cell wafer; Encapsulating the tandem solar cell wafer between a backplane and a transparent cover plate through a packaging material to make the perovskite silicon heterojunction tandem solar cell.

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