Bifacial double perovskite solar cell, module and solar panel comprising the same

Abstract

Bifacial double perovskite solar cell (1), comprising: a first transparent support (2) having a bottom surface (21), lateral surface (22) and top surface (23); a first monofacial perovskite solar cell (3) supported by the first transparent support (2) and including a photoactive perovskite layer (4), on the top surface (23) of the first transparent support (2), and an opaque electrode (5) on top of the photoactive perovskite layer (4), first electrodes (6) arranged on the first transparent support (2), electrically connected to the first monofacial perovskite solar cell (3), and external contacts (61) on the bottom surface (21) and / or lateral surface (22) of the first transparent support (2), the first electrodes (6) electrically connecting the respective external contacts (61); a protective encapsulant sealing layer (7), covering the top surface (23) of the first transparent support (2), the first electrodes (6) and the opaque electrode (5) of the first monofacial perovskite solar cell (2); a second transparent support (20) having a bottom surface (201), lateral surface (202) and top surface (203); a second monofacial perovskite solar cell (30) supported by the second transparent support (20) and including a photoactive perovskite layer (40) on the top surface (203) of the transparent support (20) and an opaque electrode (50) on top of the photoactive perovskite layer (40); second electrodes (60) arranged on the second transparent support (20), electrically connected to the second monofacial perovskite solar cell (30), and external contacts (610) on the bottom surface (201) and / or lateral surface (202) of the second transparent support (20), the second electrodes (60) electrically connecting the respective external contacts (610); wherein the second monofacial perovskite solar cell (30) is arranged relative to the first monofacial perovskite solar cell (3) so that the opaque electrode (50) of the second monofacial perovskite solar cell (30) faces the opaque electrode (5) of the first monofacial perovskite solar cell (3), the protective encapsulant sealing layer (7) covers the top surface (203) of the transparent support (30), the second electrodes (60) and the opaque electrode (50) of the second monofacial perovskite solar cell (30), and the first monofacial perovskite solar cell (3) and the second monofacial perovskite solar cell (30) are electrically connected to each other through the respective external contacts (61, 610).

Description

[0001] P1740PC00

[0002] - 1 - Bl FACIAL DOUBLE PEROVSKITE SOLAR CELL, MODULE AND SOLAR PANEL COMPRISING THE SAME

[0003] ***

[0004] FIELD OF INVENTION

[0005] The present invention relates to a perovskite solar cell. More particularly, the present invention relates to an improved perovskite solar cell, a module provided with a plurality of said perovskite solar cells and a solar panel comprising a plurality of said modules.

[0006] BACKGROUD OF THE INVENTION

[0007] Perovskite solar cells (also hereinafter indicated as PSCs) represent an emerging photovoltaic technology that has attracted significant attention due to the high efficiency and potential for cost-effective manufacturing.

[0008] In the present invention and the following claims, with the term "perovskite" a class of different materials is intended, all characterized by a specific crystal structure, typically represented by the formula ABX3, where "A" and "B" represent cations (usually MA+, FA+ or Cs+) and "X" is the anion, such as chloride, bromide, or iodide. By varying or combining different cations and anions, a wide range of photoactive perovskites with different optical and electronic properties can be synthesized such as MAPbh, CsPbh, etc., all falling under the term "perovskite".

[0009] Different architectures of perovskite solar cells have been developed, depending on the position of the layers in the solar cell structure (p-i-n and n-i-p). The photoactive perovskite layer, which absorbs incoming light radiation through a glass layer, is usually located between chargetransporting layers (CTLs) (as represented in prior art Figure 1). Specifically, the photoactive perovskite layer is sandwiched between an electron-transporting layer (ETL, or n-layer) and a hole-transporting layer (HTL, or p-layer). These layers facilitate the extraction of photogenerated charges from the perovskite, directing them to both the top and bottom electrodes. In some architectures, the HTL is eliminated being substituted by a Carbon electrode serving as top electrode (see prior art Figure 1 on the bottom right). In other architectures the layers can have a mesoporous habit (see prior art Figure 1 on the bottom left). All PSCs are fabricated on and are supported by a support, for example a glass substrate or a flexible plastic foil (as disclosed in Jena et al., Chemical Reviews 2019119 (5), 3036-3103).

[0010] Perovskite solar cells have recently surpassed the power conversion efficiency (PCE) record of traditional silicon solar cells, reaching 26.7% (https: / / www.nrel.gov / pv / cell-P1740PC00

[0011] - 2 -efficiency.html). In addition to their traditional use as single-junction solar cells, perovskites are increasingly integrated with silicon in tandem cell configurations. This combination results in devices with efficiencies higher than those of either silicon or perovskite cells alone, due to the complementary absorption characteristics across the solar spectrum. A promising application of perovskite solar cells is the Internet of Things (loT) powering under indoor environments, where they demonstrate superior efficiency compared to silicon solar cells. They can be used to power sensors, such as humidity and temperature sensors, as well as various devices for smart home automation.

[0012] The perovskite solar cells known in the art, however, suffer for important drawbacks, as perovskite materials are, in fact, very sensitive to environmental factors such as moisture, heat, and UV light, which can lead to performance degradation over time. The encapsulation of the solar cells is thus crucial to avoid the degradation of perovskite materials, and one of the most effective ways to encapsulate a PSC is through cover glass encapsulation. The cover glass is placed over the PSC and secured with an encapsulant applied along the surface and edges of the device to block moisture, as disclosed by Wang et al., ACS Materials Au 20222 (3), 215-236) and represented in prior art Figure 2. Cover glass encapsulation certainly offers the benefit of enclosing the device between two moisture-impermeable surfaces, significantly reducing the potential entry points for moisture through the sealant between the substrate and cover glass. As a result, this type of encapsulation generally provides better performance than other kinds.

[0013] However, enhancing power generation of PSCs is also a challenge. A straightforward and cost-effective approach in literature is using bifacial single PSC designs, which capture both reflected and diffuse sunlight from the ground (as disclosed in Song et al., Advanced Materials 2022, 34, 2106805). For indoor photovoltaic (PV), optimized bifacial single PSC designs can more efficiently harness ambient light, improving performance in low-light environments, particularly in vertical or inclined configurations. Traditional bifacial single perovskite solar cells, as depicted in prior art Figure 3, are made of a single PSC and employ transparent top and bottom electrodes (instead of opaque metal or carbon), allowing light to enter from both sides. This design maximizes photon absorption and improves overall efficiency. However, current and voltage cannot be boosted over the maximum limit of a single cell. Moreover, A drawback of bifacial PSCs is their relatively high series resistance due to the low conductivity of the top transparent conductive oxide (TCO) electrode. This occurs because thermal annealing of the top transparent electrode, required to reduce sheet resistance, cannot be performed without damaging theP1740PC00

[0014] - 3 -perovskite stack. This further leads to reduced optical quality of the top transparent electrode and increased parasitic optical absorption when illumination occurs through the top electrode. The elevated series resistance results in electrical power loss, particularly at higher photocurrent levels. Accordingly, under bifacial illumination, bifacial PSCs experience more significant series resistance and optical losses compared to their monofacial counterparts with opaque electrodes (as disclosed in Song et al., Adv. Mater. 2022, 34, 2106805). Additionally, this bifacial architecture requires encapsulation with additional cover glass and sealers, as previously discussed, to prevent performance degradation. Prior art documents CN108336155A, CN108717948A, CN109244153A, EP4365964A4, and US11088294B2, all describe traditional perovskite solar cells constructed directly on the silicon solar cell by sequentially depositing materials on both sides through different strategies of fabrication (so called, Bifacial Tandem Solar cells). Similarly, prior art document MARTIN AMAURY ET AL: "Architecture of symmetrical bifacial perovskite / Si / perovskite PV modules..." discloses a symmetrical bifacial tandem module using transparent electrodes. GAO YUAN ET AL: "Performance optimization of monolithic allperovskite tandem solar cells..." describes optimizing such tandem cells via current mismatch. An alternative approach is found in US 2024 / 0130145 Al, which describes a bifacial structure using asymmetric transparent composite conductors to reduce electrical resistance. Even in such cases, additional cover glass and sealing materials are necessary to prevent performance degradation.

[0015] In view of the above, it is clear that the need to address the above issues is still felt, and the main object of the present invention is to provide a simple, stable and highly performing perovskite solar cell, wherein power losses are limited and current and voltage can be boosted over the maximum limit of a traditional single PSC.

[0016] SUMMARY OF THE INVENTION

[0017] It is a specific object of the invention, a bifacial double perovskite solar cell comprising: - a first transparent support having a bottom surface, lateral surface and top surface;

[0018] - a first monofacial perovskite solar cell supported by the first transparent support and including a photoactive perovskite layer on the top surface ofthe first transparent support, and an opaque electrode on top of the photoactive perovskite layer,

[0019] - first electrodes arranged on the first transparent support, electrically connected to the first monofacial perovskite solar cell, and external contacts on the bottom surface and / or lateral surface ofthe first transparent support, the first electrodes electrically connecting the respectiveP1740PC00

[0020] -4-external contacts;

[0021] - a protective encapsulant sealing layer, covering the top surface of the first transparent support, the first electrodes and the opaque electrode of the first monofacial perovskite solar cell;

[0022] - a second transparent support having a bottom surface, lateral surface and top surface;

[0023] - a second monofacial perovskite solar cell supported by the second transparent support and including a photoactive perovskite layer on the top surface of the transparent support, and an opaque electrode on top of the photoactive perovskite layer;

[0024] - second electrodes arranged on the second transparent support, electrically connected to the second monofacial perovskite solar cell, and external contacts on the bottom surface and / or lateral surface of the second transparent support, the second electrodes electrically connecting the respective external contacts;

[0025] wherein

[0026] the second monofacial perovskite solar cell is arranged relative to the first monofacial perovskite solar cell so that the opaque electrode of the second monofacial perovskite solar cell faces the opaque electrode of the first monofacial perovskite solar cell, the protective encapsulant sealing layer covers the top surface of the transparent support, the second electrodes and the opaque electrode of the second monofacial perovskite solar cell, and the first monofacial perovskite solar cell and the second monofacial perovskite solar cell are electrically connected to each other through the respective external contacts.

[0027] According to an aspect of the invention, the first monofacial perovskite solar cell and the second monofacial perovskite solar cell can be electrically connected with each other in a series or a parallel electrical connection.

[0028] According to another aspect of the invention, the first monofacial perovskite solar cell and the second monofacial perovskite solar cell can have the same architecture.

[0029] According to an additional aspect of the invention, the first monofacial perovskite solar cell and the second monofacial perovskite solar cell can have different architectures.

[0030] According to an aspect of the invention, the perovskite composition of the photoactive perovskite layer in the first monofacial perovskite solar cell can be identical to the perovskite composition of the photoactive perovskite layer in the second monofacial perovskite solar cell.

[0031] According to another aspect of the invention, the perovskite composition of photoactive perovskite layer in the first monofacial perovskite solar cell can be different from the perovskite composition of photoactive perovskite layer in the second monofacial perovskite solar cell.P1740PC00

[0032] - 5 - According to an additional aspect of the invention, the protective encapsulant sealing layer comprises an encapsulant material comprising ethylene-vinyl acetate and / or polyurethane and / or polyolefin and / or a composite material comprising a thermosetting resin, a compatibilizer and a polyethylene glycol and optionally a UV absorber.

[0033] According to an aspect of the invention, between the opaque electrode on the first monofacial perovskite solar cell and / or the opaque electrode on the second monofacial perovskite solar cell and the protective encapsulant sealing layer, an additional insulating layers can be comprised, optionally including a polyimide film.

[0034] It is also a specific object of the present invention, a solar module comprising a plurality of bifacial double perovskite solar cells according to the above, arranged side by side, and electrically connected with each other, optionally in a series or parallel electrical connection or a combination thereof, through the respective external contacts.

[0035] According to an aspect of the invention, the plurality of bifacial double perovskite solar cells of the module above can share:

[0036] - a single first transparent support, supporting all first monofacial perovskite solar cells of the plurality of bifacial double perovskite solar cells, wherein the first monofacial perovskite solar cells can be electrically connected with each other optionally by applying a laser patterning and / or additional opaque electrodes;

[0037] - a single second transparent support, supporting all second monofacial perovskite solar cells of the plurality of bifacial double perovskite solar cells, wherein the second monofacial perovskite solar cells can be electrically connected with each other optionally by applying a laser patterning and / or additional opaque electrodes; and

[0038] - a single protective encapsulant sealing layer, that can be sandwiched between the first monofacial perovskite solar cells and the second monofacial perovskite solar cells.

[0039] According to another aspect of the invention module above, the number of first perovskite solar cells supported by the first transparent support and the number of second perovskite solar cells supported by the second transparent support can be the same.

[0040] According to an additional aspect of the invention module above, the number of first perovskite solar cells supported by the first transparent support and the number of second perovskite solar cells supported by the second transparent support can be different.

[0041] According to an aspect of the invention, the solar module can comprise:

[0042] a support frame wherein a plurality of thorough housing seats is obtained;P1740PC00

[0043] - 6 - a plurality of bifacial double perovskite solar cells according to the above, each bifacial double perovskite solar cell being housed in a respective through housing seat,

[0044] each bifacial double perovskite solar cells being electrically connected with one or more other bifacial double perovskite solar cells of the plurality of bifacial double perovskite solar cells, through the respective external contacts, in a series or parallel electrical connections or combinations thereof.

[0045] It is also a specific object of the invention a solar Panel comprising a plurality of modules according to the above.

[0046] BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The present invention will be now described, by way of illustration and not by way of limitation, according to its preferred embodiments, with particular reference to the attached Figures, wherein:

[0048] Figure 1 shows different configurations of state-of-the-art monofacial perovskite solar cells supported by respective transparent supports;

[0049] Figure 2 is a schematic representation of an encapsulated monofacial perovskite solar cell according to the state of the art;

[0050] Figure 3 represents a schematic perspective view of a bifacial single perovskite solar cell, according to the state of the art, wherein both electrodes are transparent to light radiation;

[0051] Figures 4a and 4b show a schematic exploded view with transparent parts and a corresponding assembled view with transparent parts of a bifacial double perovskite solar cell according to a first embodiment of the invention, respectively;

[0052] Figures 5a and 5b represent a schematic view of an experiment setting including the use of the bifacial double perovskite solar cell of the invention, and the resulting data collected therefrom, respectively;

[0053] Figures 6, 7 and 8 are schematic representations of: a traditional monofacial single perovskite solar cell (Fig. 6, on the left) and a bifacial double perovskite solar cell according to the invention (Fig. 6, on the right), first results (Fig. 7) and second results (Fig. 8), respectively, of experiments conducted on said monofacial single PSC and bifacial double PSC;

[0054] Figure 9 represents test results demonstrating the effectiveness of protection from moisture and environmental agents achieved by the bifacial double perovskite solar cell of the invention;

[0055] Figures 10a and 10b show a schematic view of another experiment setting including theP1740PC00

[0056] - 7 -use of a bifacial double perovskite solar cell of the invention, and the resulting data collected therefrom, respectively;

[0057] Figures 11a and lib are a schematic exploded view with transparent parts and a corresponding assembled view with transparent parts, of a solar module according to an embodiment of the invention;

[0058] Figure 12 is a schematic exploded view with transparent parts of the solar module of Figures 11a and lib, according to a variant of the invention;

[0059] Figure 13 depicts a solar module according to another embodiment of the invention; and Figure 14 is a graphical representation of the performance of the module of Figure 13, with respect to the performance of a single monofacial traditional module, under the same test conditions.

[0060] In the Figures identical reference numerals will be used for alike elements.

[0061] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0062] With particular reference to the enclosed Figures 4a and 4b, it will be appreciated that a bifacial double perovskite solar cell according to the present invention is generally referred to with reference numeral 1 and comprises a first transparent support 2, with a bottom, lateral and top surface (indicated in the figures with reference numbers 21, 22 and 23) respectively, for example made of a glass substrate and / or any other suitable flexible plastic transparent material and / or any other suitable transparent material, and a first monofacial perovskite solar cell 3 supported by that first transparent support 2.

[0063] The first monofacial perovskite solar cell 3 comprises a photoactive perovskite layer 4 comprising perovskite as defined above and / or a perovskite blend of, for example, TiCh / perovskite or Carbon / perovskite, supported on the top surface 23 of the first transparent support 2, and an opaque electrode 5 on top thereof.

[0064] Optionally, in the first monofacial perovskite solar cell 3, the photoactive perovskite layer 4 on the top surface 23 of the first transparent support 2 can be sandwiched between an electron-transporting layer (ETL, or n-layer) and a hole-transporting layer (HTL, or p-layer) or, alternatively, the hole-transporting layer can be substituted by a Carbon electrode, serving as the opaque electrode 5 on top thereof, as in the prior art bottom right Figure 1.

[0065] The bifacial double perovskite solar cell 1 of the invention also comprises first electrodes 6 electrically connected to the first perovskite solar cell 3 and arranged on the first transparent support 2, for example on the top surface 23 thereof, and respective external contacts 61 on theP1740PC00

[0066] - 8 -bottom surface 21 and / or lateral surfaces 22 of the first transparent support 2, to which the first electrodes 6 are electrically connected. In Figures 4a, for example, first electrodes 6 are illustrated on the top surface 23 of the first transparent support 2 and the external contacts 61 are on the lateral surface 22 of the same.

[0067] The bifacial double perovskite solar cell 1 of the invention also comprises a protective encapsulant sealing layer 7, covering the top surface 23 of the first transparent support 2, the first electrodes 6, and the opaque electrode 5 of the first monofacial perovskite solar cell 3 (or the Carbon electrode, serving as the opaque electrode 5, depending on the configuration of the first monofacial perovskite solar cell 3).

[0068] The bifacial double perovskite solar cell 1 of the invention, contrary to the prior art architecture of monofacial PSC comprising a glass cover over the protective encapsulant sealing layer 7 (as represented in Fig. 2), advantageously comprises a second transparent support 20 with a bottom, lateral and top surface (indicated in the figures with reference numbers 201, 202 and 203) respectively, for example made of a glass substrate or any other suitable flexible plastic transparent material and / or any other suitable transparent material, and a second monofacial perovskite solar cell 30, supported by that second transparent support 20.

[0069] The second monofacial perovskite solar cell 30 comprises a photoactive perovskite layer 40 comprising perovskite as defined above and / or a perovskite blend of, for example, TiO2 / perovskite or Carbon / perovskite, on the top surface 203 of the transparent support 20 and an opaque electrode 50 on top thereof.

[0070] Optionally, the photoactive perovskite layer 40 on the top surface 203 of the second transparent support 20 can be sandwiched between an electron-transporting layer (ETL, or n-layer) and a hole-transporting layer (HTL, or p-layer) or, alternatively, the hole-transporting layer can be substituted by a Carbon electrode, serving as the opaque electrode 50 on top thereof, as in the prior art.

[0071] The bifacial double perovskite solar cell 1 of the invention also comprises second electrodes 60, electrically connected to the second perovskite solar cell 30 and arranged on the second transparent support 20, for example on the top surface 203 thereof, and respective external contacts 610 on the bottom and / or lateral surfaces of the second transparent support 20, to which the second electrodes 60 are electrically connected. In Figures 4a, for example, second electrodes 60 are illustrated on the top surface 203 of the second transparent support 20 and the external contacts 610 on the lateral surface 202 of the same.P1740PC00

[0072] - 9 - Advantageously, in the bifacial double perovskite solar cell 1 of the invention, the second monofacial perovskite solar cell 30 is arranged relative to the first monofacial perovskite solar cell 3 so that:

[0073] - the opaque electrode 50 of the second monofacial perovskite solar cell 30 faces the opaque electrode 5 of the first monofacial perovskite solar cell 3, and

[0074] - the protective encapsulant sealing layer 7 also covers the top surface 203 of the second transparent support 20, the second electrodes 60, and the opaque electrode 50 of the second monofacial perovskite solar cell 30.

[0075] With such a configuration, it is clear that each monofacial perovskite solar cell (3, 30) in the bifacial double perovskite solar cell 1 of the invention is protected from moisture and possible other environmental agents / pollutants which can lead to performance degradation over time, by the presence of the protective encapsulant sealing layer 7 and the other monofacial perovskite solar cell (30, 3).

[0076] According to another particularly advantageous aspect of the invention, the first monofacial perovskite solar cell 3 and the second monofacial perovskite solar cell 30 in the bifacial double perovskite solar cell 1 of the invention are also electrically connected to each other through the respective external contacts (61, 610).

[0077] With reference to the electrical connection of the first monofacial perovskite solar cell 3 and second monofacial perovskite solar cell 30, they can be electrically connected with each other in a series or a parallel electrical connection and, depending on the type of electrical connection (whether series or parallel), and the architecture / configuration (i.e. the mutual arrangement of the monofacial perovskite solar cell components such as the perovskite layer, opaque electrode, ETL, HTL, etc..) of the first monofacial perovskite solar cell 3 with respect to the second monofacial perovskite solar cell 30, and the composition of perovskite material used in the photoactive perovskite layer (4, 40), as will be better explained below, the voltage or the current measured across the bifacial double perovskite solar cell 1 of the invention, can be higher than the one produced by a state-of-the-art monofacial perovskite solar cell and also by either one of the first monofacial perovskite solar cell 3 or second monofacial perovskite solar cell 30 of the bifacial double perovskite solar cell 1 of the invention.

[0078] It should be noted that both the first monofacial perovskite solar cell 3 and the second monofacial perovskite solar cell 30 of the bifacial double perovskite solar cell 1 of the invention can have an architecture / configuration according to the prior art, for example just likeP1740PC00

[0079] - 10 -represented in Figure 1. According to a preferred embodiment of the invention, in fact, the opaque electrode (5, 50) in both the first monofacial perovskite solar cell 3 and second monofacial perovskite solar cell 30 can be a traditional metal electrode or a carbon electrode. According to another embodiment of the invention, as already disclosed above, between the first transparent support 2 and the photoactive perovskite layer 4 and between the photoactive perovskite layer 4 and the opaque electrode 5 of the first monofacial perovskite solar cell 3, a charge-transporting layer can be provided (ETL or HTL, not shown in the Figures 4a and 4b), in order to enhance the extraction of photogenerated charges from the photoactive perovskite layer 4, when the photoactive perovskite layer 4 is hit by the light radiation, directing them to the respective first electrode 6. The same applies also to the second transparent support 20 and the photoactive perovskite layer 40 and the photoactive perovskite layer 40 and the opaque electrode 50 of the second monofacial perovskite solar cell 30, wherein a charge-transporting layer can be provided (ETL or HTL, not shown in the Figures 4a and 4b), in order to enhance the extraction of photogenerated charges from the photoactive perovskite layer 40, when the photoactive perovskite layer 40 is hit by the light radiation, directing them to the respective second electrode 60. According to still another preferred embodiment of the invention, the layers of the first monofacial perovskite solar cell 3 and second monofacial perovskite solar cell 30 can have a mesoporous habit. According to a further preferred embodiment of the invention, between the opaque electrode (5, 50) and the protective encapsulant sealing layer 7, in both the first monofacial perovskite solar cell 3 and / or the second monofacial perovskite solar cell 30, an additional insulating layer can be comprised (not represented in the figures), optionally including a polyimide film, such as the one developed by DuPont, under the commercial name of Kapton.

[0080] With reference to the protective encapsulant sealing layer 7, according to a preferred embodiment of the invention, such a protective encapsulant sealing layer 7 can comprise ethylene-vinyl acetate (EVA) and / or polyurethane and / or polyolefin and / or a composite material advantageously comprising a thermosetting resin, a compatibilizer and a polyethylene glycol and optionally a UV absorber, as disclosed in Italian patent application n. IT 102024000011338, and / or in general any sealing layer that can be specifically used in perovskite applications. The protective encapsulant sealing layer 7 of the bifacial double perovskite solar cell 1 of the invention, in fact, can be integrated on the top surface (23, 203) of the first and / or second transparent support (2, 20) and the respective opaque electrode (5, 50) either as a laminated foil or as a glue or as a liquid polymer applied through drop-casting, spin-coating, orP1740PC00

[0081] - 11 -blade coating, provided the deposition method is compatible with the perovskite material of the photoactive perovskite layer (4, 40) and other materials of the monofacial PCSs with reference to temperature, pressure, solvent compatibility, and related parameters. For clarity, it is specified that the term 'compatibilizer' is a term of art in polymer chemistry. As defined by the International Union of Pure and Applied Chemistry (IUPAC), a compatibilizer is an additive which, when added to an immiscible polymer blend, modifies and stabilizes the interface, making the blend more stable and homogeneous.

[0082] Going back to the voltage or the current measured across the bifacial double perovskite solar cell 1 of the invention, they can advantageously double the one produced by a state-of-the art monofacial perovskite solar cell and, more generally, multiply by a factor greater than one the one produced by either one of the first monofacial perovskite solar cell 3 and second monofacial perovskite solar cell 30 alone. For example, with a bifacial double perovskite solar cell 1 of the invention, when the first monofacial perovskite solar cell 3 and the second monofacial perovskite solar cell 30 are identical, i.e. they have the same architecture (configuration) and the photoactive perovskite layer (4, 40) of both monofacial PSCs is the same, the voltage or the current measured across the bifacial double perovskite solar cell 1 of the invention can double the one produced by the first monofacial perovskite solar cell 3 and second monofacial perovskite solar cell 30 alone.

[0083] In will be noted, in fact, that according to a preferred embodiment of the invention, the first monofacial perovskite solar cell 3 and second monofacial perovskite solar cell 30 can have the same architecture / configuration, i.e. they can both be configured as represented for example in one of the prior art examples of Figure 1. Alternatively, the first monofacial perovskite solar cell 3 and second monofacial perovskite solar cell 30 in the bifacial double perovskite solar cell 1 of the invention can have different architectures / configurations. For example, one can be configured as represented in one of the prior art examples of Figure 1 and the other can be configured as represented in another one of the prior art examples of Figure 1.

[0084] According to a preferred embodiment of the invention, the perovskite composition of the photoactive perovskite layer 4 in the first monofacial perovskite solar cell 3 can be identical to the perovskite composition of the photoactive perovskite layer 40 in the second monofacial perovskite solar cell 30. Alternatively, the perovskite composition of the photoactive perovskite layer 4 in the first monofacial perovskite solar cell 3 can be different from the perovskite composition of the photoactive perovskite layer 40 in the second monofacialP1740PC00

[0085] - 12 -perovskite solar cell 30.

[0086] However, when the first monofacial perovskite solar cell 3 and the second monofacial perovskite solar cell 30 are electrically connected in series, the voltage measured across the bifacial double perovskite solar cell 1 of the invention, is higher than the one produced by either the first monofacial perovskite solar cell 3 or second monofacial perovskite solar cell 30 alone and, when the first monofacial perovskite solar cell 3 and the second monofacial perovskite solar cell 30 are electrically connected in parallel, the current measured across the bifacial double perovskite solar cell 1 of the invention is higher than the one produced by either the first monofacial perovskite solar cell 3 or second monofacial perovskite solar cell 30 alone. When the first monofacial perovskite solar cell 3 and the second monofacial perovskite solar cell 30 are identical and are electrically connected in series, the voltage measured across the bifacial double perovskite solar cell 1 of the invention, is double the one produced by either the first monofacial perovskite solar cell 3 or second monofacial perovskite solar cell 30 alone, and when the first monofacial perovskite solar cell 3 and second monofacial perovskite solar cell 30 are identical and are electrically connected in parallel, the current measured across the bifacial double perovskite solar cell 1 of the invention, is double the one produced by either the first monofacial perovskite solar cell 3 or second monofacial perovskite solar cell 30 alone.

[0087] This is because the light radiation can hit both the first transparent support 2 and the second transparent support 20 of the bifacial double perovskite solar cell 1 of the invention, and each one of the monofacial PSC can thus contribute at least in part to the extraction of photogenerated charges from the respective photoactive perovskite layer or layers (4, 40).

[0088] In this regard, some preliminary tests have been carried out with a bifacial double perovskite solar cell 1 according to the invention, which will be illustrated in the following and prove the extremely high efficiency of this technical solution.

[0089] A bifacial double perovskite solar cell 1 was produced, having two identical HTL-free mesoporous Carbon monofacial perovskite solar cells (3, 30) each one with a AVA-MAPbh perovskite photoactive layer (4, 40), bonded through an protective encapsulant layer 7, and electrically connected in parallel. The area of the bifacial double perovskite solar cell 1 was 1.5 cm2. The protective encapsulant layer 7 between the first monofacial perovskite solar cell 3 and the second monofacial perovskite solar cell 30 was a foil made of a blend of polyolefin and paraffin wax, which was vacuum-laminated at 70 °C to bond the two monofacial PSCs (3, 30) together, with a layer of Kapton tape used as an interlayer.P1740PC00

[0090] - 13 - The bifacial double perovskite solar cell 1 was used for indoor application and kept in a vertical arrangement as represented in Figure 5a. Each side of the bifacial double perovskite solar cell 1 was illuminated separately with two LED bulbs (1800 lux each) inside a black painted box, to avoid diffused light. With this configuration, the left bulb illuminated only the first monofacial perovskite solar cell 3, while the right bulb illuminated only the second monofacial perovskite solar cell 30. Figure 5b show a graph of the power produced by the bifacial double perovskite solar cell 1 produced when a single bulb is on, i.e. when only one side of the bifacial double perovskite solar cell 1 is active, and when both bulbs are on, i.e. both monofacial perovskite solar cells 3 and 30 are hit by the light radiation. In the first case, the produced power amounts to about 125 pW (at fixed voltage corresponding to the maximum power point of 0.48 V). When both bulbs are on, both sides of the bifacial double perovskite solar cell 1 are illuminated, resulting in a total power output of about 250 pW.

[0091] Another test was carried out, see Figures 6 to 8, with the bifacial double perovskite solar cell 1 of the previous test arranged in vertical configuration (Fig. 6 on the right), inside a box containing five (5) LED lamps of 6500 K with white-painted walls, to simulate the indoor illumination conditions at different illuminance conditions. The obtained results were compared with the results obtained, under the same test conditions, with a traditional monofacial HTL-free mesoporous Carbon perovskite solar cell encapsulated with a cover glass, used as a reference (Fig. 6 on the left). Figure 7 shows the current density curve of both PSCs under different illumination conditions. It can be appreciated that the current density produced by the invention bifacial double perovskite solar cell 1 is twice the one produced by the reference PCS under all illumination condition. The analysis of J-V curves under varying illumination conditions (horizontal axis of the graphs), along with the extracted electrical power values and stabilized power output at a fixed voltage of 0.48 V, demonstrates that the bifacial double perovskite solar cell 1 of the invention produces approximately twice the power output of a traditional monofacial PSC (see Fig. 8). This increase is clearly due to a twofold enhancement in photogenerated current. For instance, at a vertical illuminance value of 920 lux, the monofacial PSC generated 24.64 pW, while the bifacial double PSC yields 51.3 pW (Fig. 7, on the right). Figure 9 shows the normalized power output of the bifacial double perovskite solar cell 1 used for the previous tests and unencapsulated monofacial perovskite solar cell stored in ambient conditions (35-50% RH - relative humidity) over time. The bifacial double perovskite solar cell 1 demonstrates excellent long-term stability, maintaining 93% of the initial power valueP1740PC00

[0092] - 14-throughout the test period (3500 h), while the monofacial perovskite solar cell degrades significantly, falling below 80 % early on, due to the degradation of the perovskite layer. This demonstrates the effectiveness of protection from moisture and environmental agents achieved by the invention bifacial double perovskite solar cell 1.

[0093] The bifacial double perovskite solar cell 1 of the invention can be advantageously used both for outdoor and indoor applications, as they can be integrated in vertical elements like inner walls, doors, frames and windows, sensors and domotic technologies' powering as well as outdoor photovoltaics building-integrated photovoltaics (BIPV), in any inclined configurations to absorb both direct and albedo light radiation.

[0094] For example, in the field of Building Integrated Photovoltaics, the bifacial double perovskite solar cell 1 of the invention can harness light from both exterior and interior sources. This has been proven with a test, wherein a bifacial double perovskite solar cells 1 of the invention was installed on a window, as represented in Figures 10a and 10b. This setup allowed one side of the bifacial double perovskite solar cell 1 to capture sunlight entering from outside during daylight hours, producing a maximum power of 1300 pW in the early morning which decreased during the day due to the reduction of incident power on the bifacial double perovskite solar cell 1, while the opposite side absorbed artificial indoor light emitted by the fluorescent lamps during nighttime, producing 13 pW (270 Lux) (Figure 10b). The skilled person will clearly understand how this bifacial functionality enables continuous energy harvesting from varying light sources, making the bifacial double perovskite solar cell 1 of the present invention especially suitable for sustainable energy solutions in urban environments and building-integrated photovoltaics (BIPV).

[0095] A plurality of bifacial double perovskite solar cells 1 described above can be integrated into a solar module 100 as represented in Figures 11a and lib, also forming an object of the invention, and comprising a plurality of bifacial double perovskite solar cells 1 arranged side by side, and electrically connected with each other, optionally in a series or parallel electrical connection or a combination thereof, through the respective external contacts (61, 610). Figures 11a and lib represent, for example, two bifacial double perovskite solar cells 1 connected with each other, but the skilled person will easily understand that a solar module 100 of the invention can comprise a larger number of bifacial double perovskite solar cells 1, connected with each other as explained above.

[0096] According to a preferred variant, in the invention solar module 100 above, the pluralityP1740PC00

[0097] - 15 -of bifacial double perovskite solar cells 1 forming the solar module 100 share:

[0098] - a single first transparent support 2, supporting all first monofacial perovskite solar cells 3 of the plurality of bifacial double perovskite solar cells 1, wherein the first monofacial perovskite solar cells 3 are electrically connected with each other, through their respective external contacts (61, 610), optionally by applying a laser patterning and / or additional opaque electrodes not represented in the figures,

[0099] - a single second transparent support 20, supporting all second monofacial perovskite solar cells 30 of the plurality of bifacial double perovskite solar cells 1, wherein the second monofacial perovskite solar cells 30 are electrically connected with each other, through their respective external contacts (61, 610), optionally by applying a laser patterning and / or additional opaque electrodes not represented in the figures, and

[0100] - a single protective encapsulant sealing layer 7, sandwiched between the first monofacial perovskite solar cells 3 and the second monofacial perovskite solar cells 30;

[0101] as represented in Figure 12.

[0102] Moreover, it should be noted that the the number of first perovskite solar cells 3 supported by the first transparent support 2 and the number of second perovskite solar cells 30 supported by the second transparent support 20 can be the same or different.

[0103] According to another variant of the present invention, represented in Figure 13, the the solar module 100 comprises a support frame 11 wherein a plurality of through housing seats 12 are obtained, and a plurality of bifacial double perovskite solar cells 1 as described above, wherein each bifacial double perovskite solar cell 1 is housed in a respective through housing seat 12 and is electrically connected to one or more of the other bifacial double perovskite solar cells 1 of the plurality of bifacial double perovskite solar cells 1, through the respective external contacts (61, 610), in a series or parallel electrical connections or combinations thereof.

[0104] More specifically, in Figure 12 a solar module 100 is represented, comprising four bifacial double perovskite solar cell 1 arranged in two parallel branches, each branch comprising two bifacial double perovskite solar cell 1 in series, so that both the current and the voltage across the module is increased with respect to a single bifacial double perovskite solar cell 1. This module 100 has been tested outdoors, arranged on the ground with an inclination of about 30° with respect to the ground, and facing south. The performance of module 100 due to the albedo light radiation hitting the same has been observed and reported on the current-voltage graph of Figure 14, wherein also the performance of a traditional corresponding module, employingP1740PC00

[0105] - 16 -monofacial PSCs, was reported. It will be noted that the invention module 100 produces about 6% more power than the traditional module using monofacial PSCs, which certainly represents an important achievement in the field of solar cells.

[0106] A plurality of modules 100 can be integrated into a solar panel (not represented in the figures), also forming an object of the invention.

[0107] The bifacial double perovskite solar cell 1 according to the invention and the corresponding modules 100 and solar panel comprising the same reach the goals disclosed in the preamble above. In fact, they provide simple, stable and highly performing perovskite solar cells, wherein power losses are limited and current and voltage can be boosted over the maximum limit of a traditional single PSC, allowing continuous energy harvesting from different light sources all day long.

[0108] The preferred embodiments of this invention have been described, and a number of variations have been suggested hereinbefore, but it should be understood that those skilled in the art can make other variations and changes without so departing from the scope of protection thereof, as defined by the attached claims.

Claims

P1740PC00- 17 - CLAIMS1. Bifacial double perovskite solar cell (1), comprising:- a first transparent support (2) having a bottom surface (21), lateral surface (22) and top surface (23);- a first monofacial perovskite solar cell (3) supported by the first transparent support (2) and including a photoactive perovskite layer (4), on the top surface (23) of the first transparent support (2), and an opaque electrode (5) on top of the photoactive perovskite layer (4), - first electrodes (6) arranged on the first transparent support (2), electrically connected to the first monofacial perovskite solar cell (3), and external contacts (61) on the bottom surface (21) and / or lateral surface (22) of the first transparent support (2), the first electrodes (6) electrically connecting the respective external contacts (61);- a protective encapsulant sealing layer (7), covering the top surface (23) of the first transparent support (2), the first electrodes (6) and the opaque electrode (5) of the first monofacial perovskite solar cell (2);- a second transparent support (20) having a bottom surface (201), lateral surface (202) and top surface (203);- a second monofacial perovskite solar cell (30) supported by the second transparent support (20) and including a photoactive perovskite layer (40) on the top surface (203) of the transparent support (20) and an opaque electrode (50) on top of the photoactive perovskite layer (40); - second electrodes (60) arranged on the second transparent support (20), electrically connected to the second monofacial perovskite solar cell (30), and external contacts (610) on the bottom surface (201) and / or lateral surface (202) of the second transparent support (20), the second electrodes (60) electrically connecting the respective external contacts (610);whereinthe second monofacial perovskite solar cell (30) is arranged relative to the first monofacial perovskite solar cell (3) so that the opaque electrode (50) of the second monofacial perovskite solar cell (30) faces the opaque electrode (5) of the first monofacial perovskite solar cell (3), the protective encapsulant sealing layer (7) covers the top surface (203) of the transparent support (20), the second electrodes (60) and the opaque electrode (50) of the second monofacial perovskite solar cell (30), and the first monofacial perovskite solar cell (3) and the second monofacial perovskite solar cell (30) are electrically connected to each other through theP1740PC00- 18 -respective external contacts (61, 610).

2. Bifacial double perovskite solar cell (1) according to claim 1, wherein the first monofacial perovskite solar cell (3) and the second monofacial perovskite solar cell (30) are electrically connected with each other in a series or a parallel electrical connection.

3. Bifacial double perovskite solar cell (1) according to any claim 1 or 2, wherein the first monofacial perovskite solar cell (3) and the second monofacial perovskite solar cell (30) have the same architecture.

4. Bifacial double perovskite solar cell (1) according to any claim 1 or 2, wherein the first monofacial perovskite solar cell (3) and the second monofacial perovskite solar cell (30) have different architectures.

5. Bifacial double perovskite solar cell (1) according to any claim 1 to 4, wherein the perovskite composition of the photoactive perovskite layer (4) in the first monofacial perovskite solar cell (3) is identical to the perovskite composition of the photoactive perovskite layer (40) in the second monofacial perovskite solar cell (30).

6. Bifacial double perovskite solar cell (1) according to any claim 1 to 4, wherein the perovskite composition of photoactive perovskite layer (4) in the first monofacial perovskite solar cell (3) is different from the perovskite composition of photoactive perovskite layer (40) in the second monofacial perovskite solar cell (30).

7. Bifacial double perovskite solar cell (1) according to any previous claim, wherein the protective encapsulant sealing layer (7) comprises an encapsulant material comprising ethylenevinyl acetate (EVA) and / or polyurethane and / or polyolefin and / or a composite material comprising a thermosetting resin, a compatibilizer and a polyethylene glycol and optionally a UV absorber.

8. Bifacial double perovskite solar cell (1) according to any previous claim, wherein between the opaque electrode (5) on the first monofacial perovskite solar cell (3) and / or the opaque electrode (50) on the second monofacial perovskite solar cell (30) and the protective encapsulant sealing layer (7), an additional insulating layers is comprised, optionally made of a polyimide film.

9. Solar module (100) comprising a plurality of bifacial double perovskite solar cells (1) according to any previous claim, arranged side by side, and electrically connected with each other, optionally in a series or parallel electrical connection or a combination thereof, through the respective external contacts (61, 610).P1740PC00- 19 - 10. Solar module (100) according to claim 9, wherein the plurality of bifacial double perovskite solar cells (1) share:- a single first transparent support (2), supporting all first monofacial perovskite solar cells (3) of the plurality of bifacial double perovskite solar cells (1), wherein the first monofacial perovskite solar cells (3) are electrically connected with each other optionally by applying a laser patterning and / or additional opaque electrodes (5);- a single second transparent support (20), supporting all second monofacial perovskite solar cells (30) of the plurality of bifacial double perovskite solar cells (1), wherein the second monofacial perovskite solar cells (30) are electrically connected with each other optionally by applying a laser patterning and / or additional opaque electrodes (50); and- a single protective encapsulant sealing layer (7), sandwiched between the first monofacial perovskite solar cells (3) and the second monofacial perovskite solar cells (30).

11. Solar module (100) according to claim 10, wherein the number of first perovskite solar cells (3) supported by the first transparent support (2) and the number of second perovskite solar cells (30) supported by the second transparent support (20) is the same.

12. Solar module (100) according to claim 10, wherein the number of first perovskite solar cells (3) supported by the first transparent support (2) and the number of second perovskite solar cells (30) supported by the second transparent support (20) is different.

13. Solar module (100) comprising:a support frame (11) wherein a plurality of thorough housing seats (12) is obtained; a plurality of bifacial double perovskite solar cells (1) according to any claim 1 to 8, each bifacial double perovskite solar cell (1) being housed in a respective through housing seat (12), each bifacial double perovskite solar cells (1) being electrically connected with one or more other bifacial double perovskite solar cells (1) of the plurality of bifacial double perovskite solar cells (1), through the respective external contacts (61, 610), in a series or parallel electrical connections or combinations thereof.

14. Solar Panel comprising a plurality of modules (100) according to any claim 9 to 13.

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