Solar cells, solar cell modules and electrical devices

Abstract

The present application provides a solar cell, a solar cell module, and an electric device, the solar cell comprising a light absorbing layer comprising a plurality of perovskite compound crystal grains, in which the light absorbing layer has, in at least one cross section perpendicular to the thickness direction thereof, a number cumulative distribution rate of perovskite compound crystal grains having a major axis D of 1 μm to 6 μm of ≧90%. The light absorbing layer according to the present application comprises, in at least one cross section perpendicular to the thickness direction thereof, perovskite compound crystal grains having a major axis D of 1 μm to 6 microns, a number cumulative distribution rate of ≧90%.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims priority to Chinese Patent Application No. 202310587850.5, filed on May 23, 2023, entitled "Solar Cell, Solar Cell Module and Electrical Device," the entire contents of which are incorporated herein by reference.

[0002] This application relates to the technical field of solar cell devices, and in particular to solar cells, solar cell modules and electrical devices. [Background technology]

[0003] Eco-friendly, renewable energy is becoming an important direction for the future development of energy technology. Solar cells, typified by perovskite photovoltaic cells, are a new energy technology that has attracted widespread attention because they can directly convert solar energy into electrical energy under sunlight irradiation.

[0004] Improving the overall performance of perovskite photovoltaic cells is an important research direction. Summary of the Invention

[0005] The object of the present application is to provide a solar cell that can improve the internal electric field strength of the solar cell, increase the open-circuit voltage, and improve its energy conversion efficiency, and to provide a solar cell module and an electrical device that include the solar cell so that the improved internal electric field strength and open-circuit voltage can be obtained and the improved energy conversion efficiency can be achieved.

[0006] In a first aspect, embodiments of the present application provide a solar cell including a light absorbing layer.

[0007] The light absorbing layer includes a plurality of perovskite compound crystal grains, and in at least one cross section perpendicular to the layer thickness direction, the number cumulative distribution rate of perovskite compound crystal grains having a major axis D of 1 μm to 6 μm is ≧90%.

[0008] According to the technical solution of the embodiment of the present application, the light absorbing layer contains perovskite compound crystal grains with a crystal grain length of 1 μm to 6 μm and a number cumulative distribution rate of ≧90% in at least one cross section perpendicular to the layer thickness direction.

[0009] This improves the crystalline quality, including the overall grain size, of the perovskite compound crystal grains in the light absorption layer, thereby achieving properties such as efficient light collection ability, extremely fast carrier transport ability, and suppression of ion migration. During power generation, the solar cell increases the overall grain size of the perovskite compound crystal grains, reduces the number of grain boundaries between the perovskite compound crystal grains, reduces or avoids interference due to interface defects, promotes charge separation at the interfaces, and improves the overall performance, including the energy conversion efficiency, of the solar cell.

[0010] Furthermore, the open-circuit voltage is affected by the minimum energy required to excite electrons and the energy gap of the semiconductor material itself; as the energy gap increases, the open-circuit voltage also increases, and the number of photons required by the material itself also decreases. During power generation, the particle size of the perovskite compound crystal grains increases, making it easier for the solar cell to have a suitable energy gap, improving light-harvesting ability and reducing the number of photons required, which helps to improve the open-circuit voltage.

[0011] In any embodiment of the present application, the light absorbing layer has a number cumulative distribution rate of perovskite compound crystal grains having a major axis D of 2.0 μm to 5.0 μm of ≧75% in at least one cross section perpendicular to the layer thickness direction.

[0012] In any embodiment of the present application, the light absorbing layer has a number cumulative distribution rate of perovskite compound crystal grains having a major axis D of 2.0 μm to 3.5 μm of ≧50% in at least one cross section perpendicular to the layer thickness direction.

[0013] In any embodiment of the present application, the light absorbing layer has a number cumulative distribution rate of perovskite compound crystal grains having a major axis D of 3.5 μm or more in at least one cross section perpendicular to the layer thickness direction of the light absorbing layer of 5% to 30%.

[0014] In any embodiment of the present application, the light absorbing layer has a number cumulative distribution rate of perovskite compound crystal grains having a major axis D of 2.5 μm to 3.0 μm of ≧60% in at least one cross section perpendicular to the layer thickness direction.

[0015] In any embodiment of the present application, the light absorbing layer has a number cumulative distribution rate of perovskite compound crystal grains having a major axis D of 1.0 μm to 2.5 μm of 20% to 40% in at least one cross section perpendicular to the layer thickness direction.

[0016] In any embodiment of the present application, the light-absorbing layer has, in at least one cross section perpendicular to the layer thickness direction, a number-integral distribution rate of perovskite compound crystal grains having a major axis D of 1.0 μm or less of ≦8%. According to the examples of the present application, a number-integral distribution rate of perovskite compound crystal grains having a major axis D of 1.0 μm to 2.5 μm falling within the above range means that the proportion of perovskite compound crystal grains having the above particle size in the entire cross section is within a suitable range, the proportion of small-sized crystal grains is low, and the uniformity of crystal grain size throughout the light-absorbing layer is improved. This uniformity of crystal grain size contributes to improving the operational stability of the solar cell during power generation.

[0017] In any embodiment of the present application, the light absorption layer has polygonal perovskite compound crystal grains with a major axis D of 1 μm to 6 μm in at least one cross section perpendicular to the layer thickness direction. The improved contact between crystal grains and reduced porosity improve carrier transport efficiency and help reduce defects between crystal grains, contributing to improved operational stability and energy conversion efficiency of the solar cell during power generation.

[0018] In any embodiment of the present application, the light absorption layer has, in at least one cross section perpendicular to the layer thickness direction, N-sided perovskite compound crystal grains with a major axis D of 1 μm to 4 μm, where N is a positive integer greater than 5 and optionally between 6 and 9. According to the examples of the present application, the polygonal perovskite compound crystal grains are in close contact with each other, which improves carrier transport efficiency and helps to reduce the effects of grain boundary defects, thereby contributing to improved operational stability and energy conversion efficiency of the solar cell during power generation.

[0019] In any embodiment of the present application, the light absorbing layer includes perovskite compound crystal grains penetrating the light absorbing layer in at least one cross section in the layer thickness direction. The perovskite compound crystal grains penetrating the light absorbing layer can be in direct contact with the first carrier transport layer and the second carrier transport layer, thereby reducing interfacial defects between the light absorbing layer and each of the first and second carrier transport layers, reducing non-radiative recombination loss between the interfaces, and reducing or avoiding current transport limitations, thereby improving the current intensity and energy conversion efficiency of the battery.

[0020] In any embodiment of the present application, the ratio of the perovskite compound crystal grains penetrating the light absorbing layer to the total number of crystal grains in the light absorbing layer is 50% to 90%, and optionally 60% to 85%. When the ratio of the perovskite compound crystal grains penetrating the light absorbing layer to the total number of crystal grains in the light absorbing layer is within the above range, it is possible to further reduce interfacial defects between the light absorbing layer and each of the first and second carrier transport layers, reduce non-radiative recombination loss between the interfaces, reduce or avoid current transport limitations, and improve the current intensity and energy conversion efficiency of the battery.

[0021] In any embodiment of the present application, the perovskite compound crystal grains include primary crystal grains and secondary crystal grains, and the number of secondary crystal grains accounts for 80% to 100%, optionally 65% ​​to 95%, of the total number of the perovskite compound crystal grains.

[0022] In any embodiment of the present application, the solar cell includes a first carrier transport layer and a second carrier transport layer.

[0023] The solar cell includes a passivation layer between the light-absorbing layer and the first carrier transport layer, and / or a passivation layer between the light-absorbing layer and the second carrier transport layer, which is used to reduce defects when the two interfaces come into contact. The passivation layer contributes to ohmic transport of carriers, reduces interfacial charge transport disorders caused by poor interface contact due to the polarity difference between the light-absorbing layer and the carrier transport layer, reduces defect density, optimizes energy levels, and promotes internal charge transfer, thereby improving the energy conversion efficiency of the perovskite solar cell.

[0024] In a second aspect, embodiments of the present application provide a method for manufacturing a solar cell.

[0025] The method for producing a solar cell includes producing a light-absorbing layer containing a plurality of perovskite compound crystal grains according to the first aspect in a non-contact sealed annealing vessel, wherein the light-absorbing layer has a number cumulative distribution rate of perovskite compound crystal grains having a major axis D of 1 μm to 6 μm of ≧90% in at least one cross section perpendicular to the layer thickness direction.

[0026] According to the examples of the present application, the light-absorbing layer manufactured by the non-contact sealed annealing vessel can improve the crystalline quality, including the overall grain size, of the perovskite compound crystal grains in the light-absorbing layer, thereby achieving properties such as efficient light-harvesting ability, extremely fast carrier transport ability, and suppression of ion migration. During power generation in the solar cell, the overall grain size of the perovskite compound crystal grains increases, the number of grain boundaries between the perovskite compound crystal grains decreases, interference caused by interfacial defects is reduced or avoided, charge separation at the interfaces is promoted, and the overall performance of the solar cell, including the energy conversion efficiency, can be improved.

[0027] In any embodiment of the present application, the method includes at least one of the following conditions:

[0028] 1) A sealed annealing vessel contains an annealing atmosphere, the annealing atmosphere contains a polar aprotic solvent, and optionally the polar aprotic solvent contains at least one of N,N-dimethylformamide, 1-methyl-2-pyrrolidone, dimethyl sulfoxide, and dimethylacetamide.

[0029] 2) The annealing temperature in the closed annealing vessel is 100-180°C, optionally 120-160°C.

[0030] 3) The annealing time in the closed annealing vessel is 8 to 30 minutes, optionally 10 to 20 minutes.

[0031] According to the embodiments of the present application, by adjusting the annealing atmosphere, annealing temperature, and annealing time in the sealed annealing vessel, the crystalline quality of the perovskite compound crystal grains, including the overall grain size, can be comprehensively controlled, and the overall performance of the solar cell, including the energy conversion efficiency, can be improved.

[0032] In a third aspect, embodiments of the present application provide a solar cell module comprising a solar cell according to the second aspect.

[0033] In a fourth aspect, an embodiment of the present application provides an electrical device comprising a solar cell module according to any of the embodiments of the third aspect of the present application, wherein the solar cell module is used to provide electrical energy.

[0034] The above description is merely a brief description of the technical solution of the present application. In order to make the technical solution of the present application more clearly understood and implemented according to the contents of the specification, and to make the above and other objectives, features and advantages of the present application more comprehensible, the following particularly sets forth specific embodiments of the present application. [Brief explanation of the drawings]

[0035] Various other benefits and advantages will become apparent to those skilled in the art upon review of the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the present application. Furthermore, like reference numerals refer to like elements throughout the drawings.

[0036] The description of the drawings follows.

[0037] [Figure 1] 1 shows a schematic diagram of measurement of the major axis, minor axis, and height in a cross section of a light absorbing layer according to an example of the present application.

[0038] [Figure 2] 1 shows a schematic diagram of the cross-sectional structure of a solar cell provided by an embodiment of the present application.

[0039] [Figure 3] 1 shows a schematic diagram of the cross-sectional structure of a solar cell provided by an embodiment of the present application.

[0040] [Figure 4] 1 shows a microscopic view of the long diameter of a perovskite compound crystal grain in a light absorbing layer of a solar cell provided by an embodiment of the present application.

[0041] [Figure 5] FIG. 2 shows a microscopic view of the long diameter of a perovskite compound crystal grain in a light absorbing layer of a solar cell provided by another embodiment of the present application.

[0042] [Figure 6] FIG. 2 shows a microscopic view of the long diameter of a perovskite compound crystal grain in a light absorbing layer of a solar cell provided by another embodiment of the present application.

[0043] [Figure 7] 1 shows a microscopic view of the height of perovskite compound crystal grains in the light absorbing layer of a solar cell provided by an embodiment of the present application.

[0044] The drawings in this application are not necessarily drawn to scale. DETAILED DESCRIPTION OF THE INVENTION

[0045] Hereinafter, the embodiments of the technical solution of the present application will be described in detail with reference to the drawings. The following embodiments are only used to more clearly explain the technical solution of the present application, and are merely examples, which should not limit the protection scope of the present application.

[0046] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. The terms used herein are only for describing specific examples and are not intended to limit the present application. The terms "comprises," "has," and any variations thereof in the specification, claims, and the above brief description of the drawings of this application are intended to cover the non-exclusive "comprises."

[0047] In the description of the examples of this application, technical terms such as "first," "second," etc. are merely used to distinguish different objects, and should not be understood as indicating or implying relative importance, or suggesting the number, specific order, or primary and secondary relationship of the technical features shown. In the description of the examples of this application, unless otherwise clearly and specifically limited, "plurality" means two or more.

[0048] When an "embodiment" is described in this specification, it means that a particular feature, structure, or characteristic described by the embodiment may be included in at least one embodiment of the present application. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it refer to an embodiment that is exclusively independent of or alternative to other embodiments. It is explicitly or implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0049] In the description of the examples of this application, the term "and / or" is merely used to explain the relationship between related objects and indicates that there may be three relationships; for example, A and / or B can represent the cases where A exists alone, A and B exist simultaneously, or B exists alone. In addition, the symbol " / " in this specification generally means that the related objects before and after it are in an "or" relationship.

[0050] In describing the examples of this application, the term "plurality" refers to two or more (including two); similarly, "sets" refers to two or more (including two sets), and "plurality" refers to two or more (including two).

[0051] In describing the examples of the present application, orientations or positional relationships indicated by technical terms such as "center," "longitudinal direction," "lateral direction," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial direction," "radial direction," and "circumferential direction" are orientations or positional relationships shown based on the drawings, and are intended merely to make the examples of the present application easier to explain and simplify the description. They do not explicitly or implicitly indicate that the devices or elements shown necessarily have a specific orientation, or are configured and operated in a specific orientation, and therefore should not be understood as limiting the examples of the present application.

[0052] In describing the embodiments of the present application, unless otherwise clearly defined or limited, technical terms such as "attach," "couple," "connect," and "fix" should be understood in a broad sense, and may refer to, for example, a fixed connection, a detachable connection, or integration. They may also refer to a mechanical connection or an electrical connection. They may also refer to a direct connection, an indirect connection via an intermediate medium, an internal communication between two elements, or an interactive relationship between two elements. Those skilled in the art will be able to understand the specific meanings of the above terms in the embodiments of the present application according to specific circumstances.

[0053] A solar cell is a device that converts light energy directly into electrical energy through the photoelectric effect or photochemical reaction. Examples of solar cells include those that use perovskite compound semiconductors as light-absorbing materials, and perovskite solar cells, which belong to the third generation of solar cells.

[0054] In perovskite solar cells, the perovskite compound absorbs photons of a certain energy, exciting the valence electrons and transferring them to the conduction band, leaving behind holes in the valence band to form bound electron-hole pairs. These electron-hole pairs are then separated into free carriers and transported to the corresponding electrodes to achieve photoelectric conversion. The crystalline quality of perovskite compounds directly affects the initial efficiency and stability of perovskite solar cells, and the crystalline quality is greatly influenced by the annealing process. During the engineering and mass production of perovskite solar cells, ensuring the consistency of the annealing temperature of perovskite compounds and the uniformity of the heat-receiving area are key challenges to ensure crystalline quality.

[0055] Currently, the most widely used annealing process is contact-type hotplate annealing, whose annealing mechanism is primarily heat conduction or heat radiation. That is, the surface of the hotplate is heated by a heating wire, and heat is then conducted through the hotplate surface to the substrate material (typically a glass or flexible substrate) of the perovskite solar cell, and finally to the perovskite. This process poses several problems. The first is the issue of uniformity due to the large heat-receiving area of ​​the perovskite layer. Conventional annealing is primarily performed using a hotplate, and the heat-receiving uniformity of the perovskite is limited by several factors, one of which is the uniformity of the hotplate. The larger the heating area, the more difficult it is to control the temperature between different regions. Another factor that is difficult to control is the substrate material of the perovskite solar cell, particularly glass. Glass undergoes distortion when exposed to heat, which directly leads to large variations in the heating rate between different regions of the perovskite layer. Due to uneven heat reception and large temperature differences between living organisms, perovskite compound crystal grains often become non-uniform in size and size distribution, and further, grain boundary defects occur. When solar cells containing perovskite compound crystal grains with non-uniform size and size distribution are used, carrier transport is affected and the large number of grain boundary defects reduces the energy conversion efficiency of the solar cell. Secondly, the perovskite crystal grains produced by the above-mentioned annealing process are small (usually smaller than 500 nm), and small perovskite crystals inevitably have numerous grain boundaries. The frequent presence of unavoidable grain boundary defects directly leads to a decrease in the open-circuit voltage and energy conversion efficiency of perovskite solar cells, seriously affecting the performance of perovskite solar cells.

[0056] Related technologies employ a swing-type thermal annealing process, in which the annealing temperature and annealing period of the perovskite photoactive layer are strictly controlled. The short heating process controls the crystal growth time, resulting in relatively orderly and gradual growth of the crystal grains in the perovskite active layer. Self-organization can occur between the perovskite crystal grains, resulting in denser and more uniform contact between the crystal grains. However, the problem this solves is the large variation or lack of uniformity in the size of the perovskite crystal grains. When fabricated using conventional contact-type hotplate annealing, the resulting perovskite crystal grains are small (usually less than 500 nm), and numerous grain boundaries still occur, inevitably resulting in numerous defects, resulting in low efficiency and poor stability of the perovskite solar cell.

[0057] In view of this, the technical solutions of the embodiments of the present application provide a solar cell that can improve the energy conversion efficiency of the solar cell by at least improving the adverse effects caused by the large number of grain boundaries and the large number of grain boundary defects in perovskite compound crystal grains due to the large crystal grain size during the power generation process of the solar cell. solar cells

[0058] In a first aspect, embodiments of the present application provide a solar cell including a light absorbing layer.

[0059] The light absorbing layer includes a plurality of perovskite compound crystal grains, and in at least one cross section perpendicular to the layer thickness direction, the number cumulative distribution rate of perovskite compound crystal grains having a major axis D of 1 μm to 6 μm is ≧90%.

[0060] According to the examples of the present application, the major axis D of the perovskite compound crystal grains is measured in a cross section perpendicular to the thickness direction of the light-absorbing layer, and optionally the minor axis b of the perovskite compound crystal grains may be measured. Since the thickness h of the perovskite compound crystal grains may be measured in a cross section in the thickness direction of the light-absorbing layer, the major axis D reflects the actual major axis of the perovskite compound crystal grains. The major axis can be understood as the longest particle diameter measured for the perovskite compound crystal grains, as shown in Figure 1.

[0061] According to the examples of the present application, the cumulative number distribution of perovskite compound crystal grains represents the percentage of the number of perovskite compound crystal grains having a specific particle size among all perovskite compound crystal grains in the cross section. The percentage is calculated based on the number. The cumulative number distribution of perovskite compound crystal grains = number of perovskite crystal grains within a size range in the corresponding SEM image / number of all perovskite crystal grains in the corresponding SEM image × 100%.

[0062] According to the technical solutions of the embodiments of the present application, crystal defects in the perovskite compound crystal grains themselves in the light absorption layer of a solar cell lead to non-radiative recombination of carriers, resulting in a certain energy loss and reducing the photoelectric conversion efficiency of the solar cell. By achieving a number-integrated distribution rate of perovskite compound crystal grains with a major axis D of 1 μm to 6 μm within the above range, the crystal quality, including the overall particle size, of the perovskite compound crystal grains in the light absorption layer can be improved, resulting in efficient light collection ability, extremely fast carrier transport ability, and suppressed ion migration. During power generation, the overall particle size of the perovskite compound crystal grains is increased, the number of grain boundaries between the perovskite compound crystal grains is reduced, interference caused by interface defects is reduced or avoided, and charge separation at the interface is promoted, thereby improving the overall performance of the solar cell, including the energy conversion efficiency.

[0063] Furthermore, the open-circuit voltage is affected by the minimum energy required to excite electrons and the energy gap of the semiconductor material itself; as the energy gap increases, the open-circuit voltage also increases, and the number of photons required by the material itself also decreases. During power generation, the particle size of the perovskite compound crystal grains increases, making it easier for the solar cell to have a suitable energy gap, improving light-harvesting ability and reducing the number of photons required, which helps to improve the open-circuit voltage.

[0064] Alternatively, the major axis D of the perovskite compound crystal grains may be any one of 1.0 μm, 1.5 μm, 2.0 μm, 2.5 μm, 3.0 μm, 3.5 μm, 4.0 μm, 4.5 μm, 4.6 μm, 4.7 μm, 4.8 μm, 4.9 μm, 5.0 μm, 5.1 μm, 5.2 μm, 5.3 μm, 5.4 μm, 5.5 μm, 5.6 μm, 5.7 μm, 5.8 μm, 5.9 μm, and 6.0 μm, or any combination thereof. The cumulative number distribution of perovskite compound crystal grains having a major axis D of 1 μm to 6 microns may be any one of 90%, 91%, 92%, 93%, 94%, 95%, 96%, and 97% or any combination thereof. By ensuring that the major axis D of the perovskite compound crystal grains is within the above range, the overall particle size of the perovskite compound crystal grains in the light absorption layer is further increased. By ensuring that the cumulative number distribution rate of perovskite compound crystal grains having a major axis D of 1 μm to 6 microns is within the above range, the overall particle size of the perovskite compound crystal grains is increased during power generation in the solar cell, the number of grain boundaries between the perovskite compound crystal grains is further reduced, and interference due to interface defects is reduced or avoided, improving energy conversion efficiency.

[0065] In some embodiments, at least one cross section perpendicular to the thickness direction of the light absorbing layer may be a cross section close to a surface in the thickness direction of the light absorbing layer. Optionally, the cross section may be a cross section of an end surface in the thickness direction of the light absorbing layer. The thickness of the surface layer is in the range of ≦100 nm, and optionally ≦50 nm.

[0066] In some optional embodiments of the present application, the light-absorbing layer has a number cumulative distribution rate of perovskite compound crystal grains having a major axis D of 2.0 μm to 5.0 μm of ≧75% in at least one cross section perpendicular to the layer thickness direction. Optionally, the number cumulative distribution rate of perovskite compound crystal grains having a major axis D of 2.0 μm to 5.0 μm may be any one of 75%, 76%, 77%, 78%, 79%, 80%, 85%, 90%, and 95%, or a combination thereof. Having the number cumulative distribution rate of perovskite compound crystal grains having a major axis D of 2.0 μm to 5.0 μm in the above range increases the overall particle size of the perovskite compound crystal grains, and having the major axis D of 2.0 μm to 5.0 μm improves the uniformity of the size of the perovskite compound crystal grains. During power generation, the number of grain boundaries between the perovskite compound crystal grains is reduced, and interference caused by interface defects is reduced or avoided, improving the energy conversion efficiency of the solar cell.

[0067] Perovskite compound crystal grains having a major axis D of 2.0 μm to 5.0 μm have a suitable energy gap, and when their number-integrated distribution rate is within the above range, the light-harvesting ability can be improved, and the open-circuit voltage of the solar cell can be increased.

[0068] In some optional embodiments of the present application, the light absorbing layer has, in at least one cross section perpendicular to the layer thickness direction, a number cumulative distribution rate of perovskite compound crystal grains having a major axis D of 2.0 μm to 3.5 μm of ≧50%. Optionally, the number cumulative distribution rate of perovskite compound crystal grains having a major axis D of 2.0 μm to 3.5 μm may be any one of 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 65%, 70%, 75%, 80%, 90%, and 95%, or any combination thereof.

[0069] According to the examples of the present application, the cumulative distribution rate of perovskite compound crystal grains having a major axis D of 2.0 μm to 3.5 μm is within the above range, thereby improving the uniformity of the size of the perovskite compound crystal grains and the overall particle size. During power generation, the number of grain boundaries between the perovskite compound crystal grains is reduced, and interference caused by interface defects is reduced or avoided, improving the energy conversion efficiency of the solar cell.

[0070] In some optional embodiments of the present application, the light absorbing layer has, in at least one cross section perpendicular to the layer thickness direction, a number cumulative distribution rate of perovskite compound crystal grains having a major axis D of 3.5 μm or more of 5% to 30%. Optionally, the number cumulative distribution rate of perovskite compound crystal grains having a major axis D of 3.5 μm or more may be any one of 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 26%, 27%, 28%, 29%, and 30%, or a range combining any of these values. According to the examples of the present application, the fact that the number-cumulative distribution rate of perovskite compound crystal grains having a major axis D of 3.5 μm or more is within the above range means that the proportion of perovskite compound crystal grains having the above particle size in the entire cross section is within a suitable range, the proportion of large-sized crystal grains is low, and the uniformity of crystal grain size throughout the light-absorbing layer is improved. This uniformity of crystal grain size contributes to improving the operational stability of the solar cell during power generation.

[0071] In some optional embodiments of the present application, the light absorbing layer has, in at least one cross section perpendicular to the layer thickness direction, a number cumulative distribution rate of perovskite compound crystal grains having a major axis D of 2.5 μm to 3.0 μm of ≧60%. Optionally, the number cumulative distribution rate of perovskite compound crystal grains having a major axis D of 2.5 μm to 3.0 μm may be any one of 60%, 61%, 62%, 63%, 64%, 65%, 70%, 75%, 80%, 81%, 82%, 83%, 84%, 90%, and 95%, or any combination thereof. According to the examples of the present application, the cumulative distribution rate of perovskite compound crystal grains having a major axis D of 2.5 μm to 3.0 μm is within the above range, thereby improving the uniformity of the size of the perovskite compound crystal grains and the overall particle size. During power generation, the number of grain boundaries between the perovskite compound crystal grains is reduced, and interference caused by interface defects is reduced or avoided, improving the energy conversion efficiency.

[0072] In some optional embodiments of the present application, the light absorbing layer has, in at least one cross section perpendicular to the layer thickness direction, a number cumulative distribution rate of perovskite compound crystal grains having a major axis D of 1.0 μm to 2.5 μm of 20% to 40%. The number cumulative distribution rate of perovskite compound crystal grains having a major axis D of 1.0 μm to 2.5 μm may be any one of 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 32%, 35%, 36%, 37%, 38%, 39%, and 40%, or any combination thereof. According to the examples of the present application, the fact that the number-cumulative distribution rate of perovskite compound crystal grains having a major axis D of 1.0 μm to 2.5 μm is within the above range means that the proportion of perovskite compound crystal grains having the above particle size in the entire cross section is within a suitable range, the proportion of small-sized crystal grains is low, and the uniformity of crystal grain size throughout the light-absorbing layer is improved. This uniformity of crystal grain size contributes to improving the operational stability of the solar cell during power generation.

[0073] In some alternative embodiments of the present application, the light-absorbing layer has, in at least one cross section perpendicular to the layer thickness direction, a number-integral distribution rate of perovskite compound crystal grains having a major axis D of 1.0 μm or less of ≦8%. The number-integral distribution rate of perovskite compound crystal grains having a major axis D of 1.0 μm or less may be any one of 1%, 2%, 3%, 4%, 5%, 6%, 7%, and 8%, or a combination thereof. According to the examples of the present application, a number-integral distribution rate of perovskite compound crystal grains having a major axis D of 1.0 μm or less in the above range means that the proportion of perovskite compound crystal grains having the above particle size in the entire cross section is in a suitable range, the proportion of small-sized crystal grains is low, and the uniformity of crystal grain size throughout the light-absorbing layer is improved. This uniformity of crystal grain size contributes to improving the operational stability of the solar cell during power generation.

[0074] In some optional embodiments of the present application, the light absorbing layer has polygonal perovskite compound crystal grains with a major axis D of 1 μm to 6 μm in at least one cross section perpendicular to the layer thickness direction.

[0075] According to the embodiments of the present application, defects in porosity or adhesion between perovskite compound crystal grains in the light absorption layer of a solar cell lead to non-radiative recombination of carriers, resulting in a certain energy loss and reducing the photoelectric conversion efficiency of the solar cell. The improved contact between the crystal grains and reduced porosity of the above-mentioned shape help improve carrier transport efficiency and reduce defects between the crystal grains, contributing to the improvement of the operational stability and energy conversion efficiency of the solar cell during power generation.

[0076] For example, as shown in FIGS. 4 to 6, perovskite compound crystal grains having a major diameter D of 1 μm to 6 μm are polygonal.

[0077] In some optional embodiments of the present application, the light absorbing layer has perovskite compound crystal grains with a major axis D of 1 μm to 4 μm in at least one cross section perpendicular to the layer thickness direction, which are N-sided polygonal, where N is a positive integer greater than 5 and optionally 6 to 9.

[0078] According to the examples of the present application, the polygonal perovskite compound crystal grains are in close contact with each other, which helps improve carrier transport efficiency and reduce the effects of grain boundary defects, thereby contributing to improved operational stability and energy conversion efficiency of the solar cell during power generation.

[0079] In some optional embodiments of the present application, the light absorbing layer includes perovskite-type compound crystal grains that penetrate the light absorbing layer in at least one cross section in the layer thickness direction.

[0080] In the examples of the present application, the perovskite compound crystal grains penetrating the light absorbing layer are measured in a cross section parallel to the thickness direction of the light absorbing layer, that is, the height h of the perovskite compound crystal grains can be measured, as shown in Figure 1. For example, the perovskite compound crystal grains penetrating the light absorbing layer are shown in Figure 7.

[0081] In solar cells, carriers generated by photoexcitation in perovskite compounds diffuse within the light-absorbing layer. When they reach the interface between the electron transport layer / hole transport layer and the light-absorbing layer, free electrons and holes form under the action of an interfacial barrier if the energy levels of the two functional layers match. Defects within the perovskite compound and at the interface between the two transport layers lead to nonradiative recombination of carriers, resulting in a certain amount of energy loss and reducing the photoelectric conversion efficiency of perovskite solar cells. Therefore, perovskite compound crystal grains penetrating the light-absorbing layer can directly contact the first and second carrier transport layers, thereby reducing interfacial defects between the light-absorbing layer and each of the first and second carrier transport layers, reducing nonradiative recombination losses between the interfaces, reducing or avoiding current transport limitations, and improving the current intensity and energy conversion efficiency of the cell.

[0082] In some optional embodiments of the present application, the ratio of the perovskite compound crystal grains penetrating the light absorbing layer to the total number of crystal grains in the light absorbing layer is 50% to 90%, and optionally 60% to 85%. When the ratio of the perovskite compound crystal grains penetrating the light absorbing layer to the total number of crystal grains in the light absorbing layer is in the above range, interfacial defects between the light absorbing layer and each of the first and second carrier transport layers are further reduced, current transport limitations are further reduced or avoided, and the current intensity and energy conversion efficiency of the battery are improved.

[0083] In some optional embodiments of the present application, the perovskite compound crystal grains include primary crystal grains and secondary crystal grains, and the number of secondary crystal grains accounts for 80% to 100%, optionally 65% ​​to 95%, of the total number of the perovskite compound crystal grains.

[0084] In the examples of the present application, primary crystal grains refer to dense, fine, and uniform crystal grains obtained from perovskite-type compounds at the initial stage of annealing. Secondary crystal grains refer to the primary crystal grains that are subsequently annealed in a trace solvent atmosphere, whereby small crystal grains dissolve one after another due to the Ostwald ripening effect, forming a solute atmosphere that is absorbed by larger crystal grains through a chemical kinetic process, gradually forming a large crystal grain structure. In other words, secondary crystal grains are crystal grains that grow at the expense of larger crystal grains with higher surface energy. Typically, the major axis of the primary crystal grains is in the range of about 100 nm to 800 nm, and the volume of the secondary crystal grains can reach 1 μm to 6 μm.

[0085] In some alternative embodiments of the present application, the perovskite compound grains comprise an organic-inorganic perovskite compound having the general formula ABX3, where A is an organic cation, B is a metal cation, and X is a halogen anion or SCN. - In some embodiments of the present application, the halogen X comprises at least one of chlorine, bromine, and iodine.

[0086] It can be seen that perovskite materials with different halide ions have different band gaps, and the halide ions are I - The band gap of perovskite materials is the smallest (typically around 1.5 eV) and the halogen ions are Cl - The band gap of perovskite materials is the largest (usually about 3 electron volts). Furthermore, perovskite materials may contain two types of halogen ions mixed together, and the mixing ratio can be continuously adjusted. Therefore, the band gap of perovskite materials can be continuously adjusted in the range of 1.5 to 3 electron volts, and the corresponding range of absorbable light wavelengths is about 414 to 820 nanometers, covering almost the entire visible light spectrum. Carriers are generated in the light absorption layer.

[0087] For example, A in ABX3 is CH3NH3+ and HC(NH2) 2+ In other words, A may contain at least one of CH3NH 3+ , HC(NH2) 2+ , or a mixture of both in any ratio. It can be understood that A can be a metal ion, e.g., Cs + , Rb + and K. + may further include at least one of:

[0088] For example, B in ABX3 is Pb 2+ , Sn 2+ and Ge 2+ It may be at least one of the following.

[0089] For example, ABX3 is CH3NH3PbI3, CH3NH3SnI3, CH3NH3PbI2Cl, CH3NH3PbI2Br, CH3NH3Pb(I 1-x Br x )3(However, 0 <x<1である)などであってもよい。

[0090] In some embodiments, the organic cation A comprises at least one of an amino group and an amino group derivative. In some embodiments, the amino group may be an alkylamino group.

[0091] In some embodiments, the amino group comprises at least one of methylamino, ethylamino, propylamino, butylamino, pentylamino, hexylamino, and amidino. The amino group derivative may comprise imidazolyl.

[0092] In some embodiments, the metal in B, the metal cation, includes at least one of lead (Pb), cesium (Cs), tin (Sn), zinc (Zn), titanium (Ti), antimony (Sb), bismuth (Bi), nickel (Ni), iron (Fe), cobalt (Co), silver (Ag), copper (Cu), gallium (Ga), germanium (Ge), magnesium (Mg), calcium (Ca), indium (In), aluminum (Al), manganese (Mn), chromium (Cr), molybdenum (Mo), and europium (Eu). B in the general formula ABX3 is selected from the above metal cations to help improve the photoelectric conversion efficiency of the light absorbing layer.

[0093] Figure 2 is a schematic diagram of the cross-sectional structure of a solar cell according to an embodiment of the present application. As shown in Figure 2, solar cell 10 has a structure in which a first electrode layer 11, a first carrier transport layer 13, a light absorption layer 15, a second carrier transport layer 14, and a second electrode layer 12 are stacked in this order.

[0094] In some embodiments of the present application, the first electrode layer 11 may be made of a conductor, which has a high work function to facilitate hole injection. Exemplarily, the conductor may be a metal, a metal oxide, and / or a conducting polymer.

[0095] For example, the first electrode layer 11 may be made of a metal, for example, the material of the first electrode 11 includes at least one of nickel (Ni), platinum (Pt), vanadium (V), chromium (Cr), copper (Cu), zinc (Zn), gold (Au), silver (Ag), or an alloy thereof. The first electrode 131 may be made of a metal oxide, for example, the material of the first electrode 131 includes at least one of zinc oxide (ZnO), indium oxide (In2O3), fluorine-doped tin oxide (FTO), indium tin oxide (ITO), nickel oxide (NiO), aluminum zinc oxide (AZO), indium zinc oxide (IZO), and gallium zinc oxide (GZO). The first electrode 131 may be made of a conductive polymer, for example, the material of the first electrode 131 includes at least one of poly(3-methylthiophene), poly(3,4-(ethylene-1,2-dioxy)thiophene) (PEDOT), polypyrrole, and polyaniline.

[0096] In the embodiment of the present application, the second electrode layer 12 may also be made of a conductor, and the conductor has a low work function to promote electron injection. Exemplarily, the material of the second electrode 12 includes at least one of copper (Cu), magnesium (Mg), aluminum (Al), nickel (Ni), silver (Ag), tin (Sn), chromium (Cr), bismuth (Bi), platinum (Pt), molybdenum (Mo), tungsten (W) or an alloy thereof, carbon (C), graphene, carbon nanotubes, fluorine-doped tin oxide (FTO), indium tin oxide (ITO), aluminum zinc oxide (AZO), indium zinc oxide (IZO), and gallium zinc oxide (GZO).

[0097] In some embodiments, the solar cell includes a first carrier transport layer 13 and a second carrier transport layer 14 disposed on either side of a light absorbing layer 15. The placement of the first carrier transport layer 13 and the second carrier transport layer 14 is related.

[0098] The carrier selectivities corresponding to the first carrier transport layer 13 and the second carrier transport layer 14 are reversed. If the first carrier transport layer 13 has electron selectivity and the second carrier transport layer 14 has hole selectivity, after the light absorbing layer 15 absorbs sunlight and generates carriers, the electrons in the carriers are selected by the first carrier transport layer 13, transported to the first electrode layer 11, and further collected in the first electrode layer 11, while the holes that have lost their electrons are selected by the second carrier transport layer 15, transported to the second electrode layer 12, and further collected in the second electrode layer 12, thereby realizing carrier separation in the perovskite compound in the light absorbing layer 15. When the first carrier transport layer 13 has hole selectivity and the second carrier transport layer 14 has electron selectivity, after the light absorption layer 15 absorbs sunlight and generates carriers, the holes that have lost electrons are selected by the first carrier transport layer 13, transport their electrical properties to the first electrode layer 11, and are further collected in the first electrode layer 11, while the electrons in the carriers are selected by the second carrier transport layer 30, transported to the second electrode layer 12, and further collected in the second electrode layer 12, thereby realizing carrier separation in the light absorption layer 15.

[0099] Furthermore, the first carrier transport layer 13 is provided on the light-receiving surface of the light-absorbing layer 15, and the second carrier transport layer 14 is provided on the non-light-receiving surface of the light-absorbing layer 15; the carrier selectivities corresponding to the first carrier transport layer 13 and the second carrier transport layer 15 are opposite; the first electrode layer 11 is provided on the surface of the first carrier transport layer 13 away from the light-absorbing layer 15; the second electrode layer 12 is provided on the side of the second carrier transport layer 14 away from the light-absorbing layer 15; and the second electrode layer 12 and the second carrier transport layer 14 are electrically connected.

[0100] According to the embodiment of the present application, the first carrier transport layer 13 and the second carrier transport layer 14 may each have a single-layer structure or a multi-layer structure.

[0101] In some embodiments of the present application, the hole-selective material includes at least one of thiophene, phthalocyanine, porphyrin, 2,2′,7,7′-tetrakis(N,N-di-p-methoxyphenylamine)-9,9′-spirobifluorene, molybdenum oxide (MoO), vanadium oxide (VO), tungsten oxide (WO and / or WO), nickel oxide (NiO), copper oxide (CuO), tin oxide (SnO), molybdenum sulfide (MoS), tungsten sulfide (WS), copper sulfide (CuS), tin sulfide (SnS), copper(I) thiocyanate (CuSCN), copper iodide (CuI), fluoro-containing phosphonic acid, carbonyl-containing phosphonic acid, carbon nanotubes, and graphene.

[0102] In some embodiments of the present application, the electron-selective material includes at least one of isomethyl [6,6]-phenyl-C61-butyrate, C60, cyano-group-containing polyphenylene vinylene, boron-containing polymer, bathocuproine, bathophenanthroline, hydroxyquinolinatoaluminum, oxadiazole compounds, benzimidazole compounds, naphthalenetetracarboxylic acid compounds, perylene derivatives, phosphine oxide compounds, phosphorus sulfide compounds, fluoro-group-containing phthalocyanine, titanium oxide (TiO2), zinc oxide (ZnO), tin oxide (SnO2), indium oxide (In2O3), gallium oxide (Ga2O3), tin sulfide (SnS), indium sulfide (In2O3), lithium fluoride (LiF), sodium fluoride (NaF), magnesium fluoride (MgF2), and zinc sulfide (ZnS).

[0103] In some optional embodiments of the present application, the solar cell includes a first carrier transport layer and a second carrier transport layer.

[0104] The solar cell includes a passivation layer between the light absorbing layer and the first carrier transport layer and / or a passivation layer between the light absorbing layer and the second carrier transport layer, which is used to reduce defects when the two interfaces meet.

[0105] Figure 3 is a schematic diagram of the cross-sectional structure of a solar cell according to an embodiment of the present application. As shown in Figure 3, solar cell 10 has a structure in which a first electrode layer 11, a first carrier transport layer 13, a first passivation layer 16, a light absorption layer 15, a second passivation layer 17, a second carrier transport layer 14, and a second electrode layer 12 are stacked in this order.

[0106] According to the embodiment of the present application, the material of the passivation layer may be a material commonly used in this field, for example, the material may be methyl-substituted carbazole molecules (Me-4PACz). The methyl-substituted carbazole molecules (Me-4PACz) may be understood as one of the self-assembled molecular layers. The thickness thereof may be 1 to 5 nm.

[0107] The light-absorbing layer in a solar cell absorbs energy and releases carriers. The released carriers diffuse within the perovskite and reach the interface between the electron transport layer / hole transport layer and the light-absorbing layer. Any defects at the interface between the perovskite compound and the two transport layers lead to non-radiative recombination of the carriers, resulting in a certain amount of energy loss and reducing the photoelectric conversion efficiency of the perovskite solar cell. The passivation layer contributes to ohmic carrier transport, reduces interfacial charge transport failures caused by poor interface contact due to the polarity difference between the light-absorbing layer and the carrier transport layer, reduces defect density, optimizes energy levels, and promotes internal charge transfer, thereby improving the energy conversion efficiency of perovskite solar cells.

[0108] In some embodiments, the solar cell includes a substrate disposed on the opposite side of the first electrode layer from the second electrode layer, the substrate being made of a mixture of one or more of glass or transparent organic polymers, the organic polymers including one or more of PET (polyethylene terephthalate) and PI (polyimide).

[0109] [Solar cell manufacturing method]

[0110] In the embodiments of the present application, the solar cell 10 may be manufactured by methods known in the art.

[0111] In some embodiments of the present application, a method for manufacturing a solar cell includes the following steps S10 to S50.

[0112] S10: A first electrode layer is prepared.

[0113] S20: A first carrier transport layer is formed on one side of the first electrode layer.

[0114] S30: A light absorbing layer is formed on the opposite side of the first carrier transport layer to the first electrode layer.

[0115] S40: A second carrier transport layer is formed on the light absorption layer on the opposite side to the first carrier transport layer.

[0116] S50: A second electrode layer is formed on the opposite side of the second carrier transport layer to the light absorption layer.

[0117] For example, the method for manufacturing the solar cell device 10 may include forming a first carrier transport layer 13, a light absorbing layer 15, a second carrier transport layer 14, and a second electrode layer 12 in this order from below on a transparent or opaque first electrode layer 11. Here, the light absorbing layer 15 may be formed by a known film formation method such as vapor deposition, sputtering, spin coating, immersion, or ion plating.

[0118] The manufacturing process of the light absorbing layer includes three steps: wet film coating, solvent quenching, and annealing.

[0119] Wet film coating involves coating a substrate with ABX3, in which the perovskite is in the form of colloidal particles and dispersed in a precursor solvent.

[0120] Solvent quenching involves rapidly removing a large amount of organic solvent from a perovskite precursor solution, leaving a small amount of organic solvent to complex with the perovskite component. At this point, the perovskite is in an intermediate state, typically with the general formula AX·BX2·organic solvent. This process allows some of the solute to form seed crystals.

[0121] Annealing involves the gradual loss of solvent molecules from the AX·BX2·organic solvent to form the complete ABX3. During annealing, the seed crystals absorb the remaining solvent molecules and the lost solute, growing into perovskite crystal grains. Typically, the solute content is constant, so the number of seed crystals is inversely proportional to the grain size.

[0122] In a second aspect, embodiments of the present application provide a method for manufacturing a solar cell.

[0123] The method for producing a solar cell includes producing a light-absorbing layer containing a plurality of perovskite compound crystal grains according to the first aspect in a non-contact sealed annealing vessel, wherein the light-absorbing layer has a number cumulative distribution rate of perovskite compound crystal grains having a major axis D of 1 μm to 6 μm of ≧90% in at least one cross section perpendicular to the layer thickness direction.

[0124] In related technology, contact hotplate annealing realizes the annealing process by heat conduction, and when engineering a large area to produce perovskite layers, the temperature rise is uneven due to the warping of the glass, which leads to inconsistent seed crystal growth rates and uneven grain sizes. Furthermore, due to the large number of seed crystals and their irreversibility, the grains are usually small (the maximum grain width is less than 500 nm).

[0125] According to the examples of the present application, the light-absorbing layer manufactured by the non-contact sealed annealing vessel can improve the crystalline quality, including the overall grain size, of the perovskite compound crystal grains in the light-absorbing layer, thereby achieving properties such as efficient light-harvesting ability, extremely fast carrier transport ability, and suppression of ion migration. During power generation in the solar cell, the overall grain size of the perovskite compound crystal grains increases, the number of grain boundaries between the perovskite compound crystal grains decreases, interference caused by interfacial defects is reduced or avoided, charge separation at the interfaces is promoted, and the overall performance of the solar cell, including the energy conversion efficiency, can be improved.

[0126] In the examples of this application, a non-contact sealed annealing vessel is used to anneal the seed crystals in a non-contact sealed oven. This allows the seed crystals to heat up uniformly, while the volatilized organic solvent molecules migrate into the annealing atmosphere, forming a specific solvent annealing atmosphere that gradually dissolves small crystal grains. Due to the Ostwald ripening effect, larger crystal grains gradually absorb the dissolved small crystal grains and grow, resulting in larger perovskite compound crystal grains with fewer grain boundaries and fewer defects. The Ostwald ripening effect is a phenomenon observed in solid solutions or liquid sols, which refers to the change in the heterogeneous structure over time, i.e., the dissolution of small crystal or sol particles in the solute and their redeposition into larger crystal or sol particles. This is due to the decrease in specific interfacial energy per unit mass, which lowers the total free energy of the system and allows the reaction to proceed spontaneously.

[0127] In any embodiment of the present application, the method includes at least one of the following conditions:

[0128] 1) A sealed annealing vessel contains an annealing atmosphere, the annealing atmosphere contains a polar aprotic solvent, and optionally the polar aprotic solvent contains at least one of N,N-dimethylformamide, 1-methyl-2-pyrrolidone, dimethyl sulfoxide, and dimethylacetamide.

[0129] 2) The annealing temperature in the closed annealing vessel is 100-180°C, optionally 120-160°C.

[0130] 3) The annealing time in the closed annealing vessel is 8 to 30 minutes, optionally 10 to 20 minutes.

[0131] According to the embodiments of the present application, by adjusting the annealing atmosphere, annealing temperature, and annealing time in the sealed annealing vessel, the crystalline quality of the perovskite compound crystal grains, including the overall grain size, can be comprehensively controlled, and the overall performance of the solar cell, including the energy conversion efficiency, can be improved.

[0132] In some embodiments, the sealed oven includes a first heating source and a second heating source. In some embodiments, the first heating source and the second heating source may be disposed opposite each other, with the space between them being used to accommodate the structure to be manufactured. The structure to be manufactured may be a laminate of a first electrode layer, a first carrier layer, and a mixture coated on the first carrier layer, with the mixture being used to manufacture a light absorbing layer. The first heating source and the second heating source may heat the sealed oven by themselves or may conduct heat from the heat sources. In some embodiments, the sealed oven includes a holder, which contacts the edge of the structure to be manufactured, and the central portion of the structure to be manufactured is suspended in the air. The position of the structure to be manufactured where it contacts the holder is ≦5 mm away from the edge of the structure to be manufactured. In some embodiments, the width of the cross section of the first heated base sheet and the second heated base sheet in the direction along the first heated source and the second heated source disposed opposite each other may be 5 to 100 mm, preferably 20 to 80 mm. In some embodiments, the surfaces of the first and second heating sources are each 28-32 mm from the surface of the structure to be fabricated, optionally 30 mm.

[0133] solar cell module

[0134] The solar cell module provided by the embodiments of the present application may include one solar cell 10 according to the first embodiment, or may include a plurality of solar cells according to the first embodiment. When there are a plurality of solar cells, the solar cells may be connected in series, in parallel, or in a composite connection, where composite connection refers to the connection of the solar cells being both in series and in parallel.

[0135] In some embodiments, the solar module includes a protective layer and / or a packaging layer.

[0136] [Protective layer]

[0137] The protective layer is provided between the package layer and the solar cell and contains a metal halide and / or an organic halide. The metal halide and organic halide in the protective layer absorb infiltrated water and oxygen gas, reducing the corrosion of the organic-inorganic perovskite compound in the light absorption layer by water and oxygen, and further improving the stability of the solar cell, which helps to extend the service life of the solar cell device.

[0138] In some alternative embodiments of the present application, the metal halide has the general formula BXk, where the value of k is in the range of 1 to 3. The organic halide has the general formula AX.

[0139] In these above-mentioned embodiments, since the metal halide and the organic halide are each represented by the above general formula, the protective layer can absorb water and oxygen and produce substances similar or identical to the precursor materials of the organic-inorganic perovskite compound, and these substances can react to produce the perovskite compound with similar functions to the organic-inorganic perovskite compound, and the solar cell has a long service life even when infiltrated with water and oxygen.

[0140] In some alternative embodiments of the present application, the organic cation in the organic-inorganic perovskite compound and the organic cation in the organic halide are the same or are homologs of each other.

[0141] In this application, homologs refer to organic compounds that are similar in structure but differ in molecular composition by a few "CH2" groups.

[0142] In these examples described above, the organic cation in the general formula ABX3 and the organic cation in the general formula AX are the same or are homologs of each other, which can facilitate the formation of an organic-inorganic perovskite compound from the organic halide and precursor material in the protective layer 15.

[0143] In some alternative embodiments of the present application, the organic cation comprises at least one of an amino group and an amino group derivative, for example, an alkylamino group.

[0144] In some alternative embodiments of the present application, the amino group comprises at least one of methylamino, ethylamino, propylamino, butylamino, pentylamino, hexylamino, and amidino. The amino group derivative comprises imidazolyl.

[0145] For example, when the organic cation in the organic-inorganic perovskite compound is the same as the organic cation in the organic halide, the organic cation in the organic-inorganic perovskite compound is methylamine (CHNH - ), the organic cation in the organic halide is also methylamine (CH3NH - )

[0146] For example, when the organic cation in the general formula ABX3 and the organic cation in the general formula AX are homologues of each other, the organic cation in the organic-inorganic perovskite compound is methylamine (CH3NH - ), the organic cation in the organic halide is ethylamino (CH3CH2NH - ), propylamine (CH3CH2CH2NH - ) may also be used.

[0147] In the embodiments of the present application, the protective layer may have a single-layer structure or a multi-layer structure, and the specific number of layers can be designed as needed.

[0148] In some optional embodiments of the present application, the protective layer comprises at least one of MOF material, activated carbon, montmorillonite, diatomaceous earth, zeolite, molecular sieve, potassium, ion exchange resin, and 2-methylimidazole zinc salt MAF-4 to provide a porous structure.

[0149] [Package Layer]

[0150] The packaging layer can protect the solar cells by packaging the solar cells between the cover plate and the base plate.

[0151] Some optional package layer materials of the present application include at least one of a thermoplastic encapsulant, a thermosetting encapsulant, and a photocurable encapsulant.

[0152] Exemplary thermoplastic sealants include at least one of ethylene-vinyl acetate copolymer, polyvinyl butyral, ethylene octene copolymer, polyisobutylene, polyolefin sealants, and butyl rubber. Exemplary thermosetting sealants include at least one of epoxy sealants, silicone sealants, and polyurethane sealants. Exemplary curable sealants include at least one of ultraviolet light curable sealants and infrared light curable sealants.

[0153] Electrical equipment

[0154] In a third aspect, embodiments of the present application provide an electrical device comprising the solar cell module according to the second aspect, wherein the solar cell module is used to provide electrical energy.

[0155] The electrical device may be used in fields such as architecture, military, tourism, national defense, and power supply, but is not limited thereto, and examples include mobile phones, tablets, laptops, electric toys, power tools, electric motorcycles, electric cars, ships, aircraft, solar-powered greenhouses, and solar-powered water heaters.

[0156]

[0157] The following examples further illustrate the disclosure of the present application, but these examples are used for interpretation only, as various modifications and variations within the scope of the disclosure will be obvious to those skilled in the art. Unless otherwise specified, all parts, percentages, and ratios described in the following examples are by weight, and all reagents used in the examples are commercially available or synthesized by conventional methods and can be used as is without further treatment. All equipment used in the examples is commercially available.

[0158] Example 1

[0159] An embodiment of the present application provides a method for manufacturing a solar cell module, the method including the following steps.

[0160] (1) Formation of solar cell device: A set of 30cm x 30cm FTO conductive glass was etched using an infrared laser to form P1 with a width of approximately 30μm. The entire glass was then divided longitudinally into 44 sub-cells, each with a series resistance greater than 10MΩ. The upper 10mm and lower 10mm were designated as the module welding areas. The surface of the etched conductive glass was then washed twice with acetone and isopropyl alcohol, immersed in deionized water and ultrasonicated for 10 minutes, dried in a forced air drying oven, and placed in a drying room (humidity less than 2%) to form the first electrode.

[0161] The washed conductive glass was subjected to magnetron sputtering to deposit a layer of nickel oxide as a hole transport layer, and the thickness of the nickel oxide layer was about 15 nm.

[0162] FA by slit coating 0.95 Cs 0.05 After coating the PbI3 perovskite host layer to obtain the heated base sheet, it was transferred to a vacuum pump and evacuated for 60 seconds to a vacuum of 15 Pa. The sealed oven contained a trace amount of N,N-dimethylformamide solvent. Non-contact annealing was performed using a sealed oven. The sealed oven had the following structure: a. The sealed oven had an upper and lower heating source hotplate, and the four walls had heat exhaust and intake holes that could be opened and closed and had adjustable air intake speeds. The heated perovskite base sheet was heated with its surface facing upward, and the upper and lower heating source hotplates were each 30 mm away from the surface of the base sheet. b. The heated base sheet holder had a structure that did not contact the center of the base sheet; only the corners had insulating support pins that contacted the edges of the substrate by 5 mm, allowing the heated base sheet to float in midair inside the sealed oven.

[0163] In the annealing process, the temperature was uniformly increased to allow for gentle crystallization, and annealing was performed at 150°C for 10 minutes to form a light-absorbing layer with a thickness of approximately 500 nm.

[0164] The device fabricated above was placed in a vacuum thermal evaporation apparatus and 4×10 -4 The device was then vacuumed to 100 Pa, and 30 nm of C60 and 8 nm of BCP were deposited as charge transport layers for the device.

[0165] After the deposition of the charge transport layer in the vacuum thermal evaporation equipment is completed, Ag is deposited on its surface at 10 nm, and then the vacuum is broken and taken out. The substrate is then etched deep to the surface of the FTO layer by laser to form P2 with a width of 150 μm, and the distance between P2 and P1 is 20 μm. Then the substrate is put into the evaporation equipment again and etched at 4 × 10 -4 A vacuum was drawn down to 100 Pa, and then a layer of Ag having a thickness of about 80 nm was deposited.

[0166] After lowering the temperature, the vacuum was broken and the sample was removed and etched deep into the surface of the FTO layer using a picosecond green light laser to form P3 with a width of 15 μm, with the spacing between P3 and P2 set to 20 μm (the positions of the etching lines were P1 / P2 / P3, respectively).

[0167] (3) Edge bead removal: The coating was removed from the solar cell device in an area extending 0.1 cm inward from the edge by a laser marking machine.

[0168] (4) Adhesion of sealant: The sealant was adhered to the edge area where the edge bead was removed.

[0169] (5) Lamination: The base plate, the solar cell device with the sealant adhered thereto, the package layer with the protective layer formed thereon, and the cover plate were laminated together to obtain a solar cell module.

[0170] Examples 2 to 6

[0171] This example differs from Example 1 in the perovskite component used in the light absorbing layer, the details of which are shown in Table 1.

[0172] Comparative Examples 1 to 3

[0173] Comparative Examples 1 to 3 were almost the same as the manufacturing method of Example 1 except that an annealing method was used in which annealing was performed for 10 minutes at 150° C. by direct contact with a hot plate.

[0174] Test part

[0175] A Gemini360 field emission scanning electron microscope manufactured by Carl Zeiss (Jena, ZEISS) was used at 3 KV. The lens was positioned 4.9-5.1 mm from the sample surface, and the imaging magnification for the surface morphology of the perovskite layer was 5-10 K, while the imaging magnification for the cross section was 20 K. Cross sections of the light absorbing layers fabricated in Examples 1-3 were examined, and the particle size distribution of the perovskite compound crystal grains therein was found to be 1-6 μm, as shown in Figures 4-6. As shown in Figure 7, the presence of perovskite compound crystal grains penetrating the light absorbing layer was also found.

[0176] Photoelectric conversion efficiency measurement: Using a standard light source (AM1.5G) with a simulated solar light source at room temperature and pressure, the voltage-current characteristic curves of the solar cells manufactured in the examples and comparative examples were measured under illumination with a 4-channel source measure unit (Keithley 2440), and the open-circuit voltage (Voc), short-circuit current density (Jsc), fill factor (FF), and energy conversion efficiency (Efficiency) of the solar cells were obtained. The test results are shown in Table 1.

[0177] Comparing the test results of Examples 1 to 10 and Comparative Examples 1 to 3 in Table 1, it can be seen that in the solar cells provided by the examples of the present application, the overall particle size of the perovskite compound crystal grains in the examples is larger than the particle size of the crystal grains in the comparative examples, the number of grain boundaries between the perovskite compound crystal grains is reduced, interference caused by interface defects is reduced or avoided, charge separation at the interface is promoted, the open circuit voltage of the solar cell is improved, and the overall performance of the solar cell, including the energy conversion efficiency, is improved.

[0178] Finally, it should be noted that the above embodiments are used only to illustrate the technical solutions of the present application and are not intended to limit the same. Although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments may be modified or equivalently substituted for some or all of their technical features, and that such modifications or substitutions do not deviate from the essence of the corresponding technical solutions and the scope of the technical solutions of the embodiments of the present application, and are all within the scope of the claims and the description of the present application. In particular, as long as there is no structural contradiction, any technical features described in the embodiments may be arbitrarily combined. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions within the scope of the claims.

[0179] Table 1: Product parameters and performance parameters of the perovskite solar cells of each example and comparative example (the crystal grains below are perovskite compound crystal grains). JPEG2025542430000002.jpg255162

[0180] In Table 1, FA represents formamidine, Cs represents cesium, Pb represents lead, and I represents iodine.

Claims

1. A solar cell including a light absorbing layer, the light absorbing layer comprises a plurality of perovskite-type compound crystal grains, and in at least one cross section of the light absorbing layer perpendicular to a layer thickness direction, a number cumulative distribution rate of perovskite-type compound crystal grains having a major axis D of 1 μm to 6 μm is ≧90%.

2. the light absorbing layer has a number cumulative distribution rate of perovskite compound crystal grains having a major axis D of 2.0 μm to 5.0 μm of ≧75% in at least one cross section perpendicular to the layer thickness direction; The solar cell according to claim 1 .

3. 3. The solar cell according to claim 1, wherein the light absorbing layer has a number-accumulated distribution rate of perovskite compound crystal grains having a major axis D of 2.0 μm to 3.5 μm of ≧50% in at least one cross section perpendicular to the layer thickness direction.

4. In the light absorbing layer, in at least one cross section perpendicular to the layer thickness direction, the cumulative distribution rate of perovskite compound crystal grains having a major axis D of 3.5 μm or more is 5% to 30%, and / or the light absorbing layer has a number cumulative distribution rate of perovskite compound crystal grains having a major axis D of 2.5 μm to 3.0 μm of ≧60% in at least one cross section perpendicular to the layer thickness direction; and / or the light absorbing layer has a number cumulative distribution rate of perovskite compound crystal grains having a major axis D of 1.0 μm to 2.5 μm of 20% to 40% in at least one cross section perpendicular to the layer thickness direction; and / or In the light absorbing layer, in at least one cross section perpendicular to the layer thickness direction, the cumulative distribution rate of perovskite compound crystal grains having a major axis D of 1.0 μm to 2.0 μm is 16.69% to 20.9%; and / or 4. The solar cell according to claim 1, wherein the light absorbing layer has a number-accumulated distribution rate of perovskite compound crystal grains having a major axis D of 1.0 μm or less in at least one cross section perpendicular to the layer thickness direction thereof of ≦8%.

5. 5. The solar cell according to claim 1, wherein the light absorbing layer has polygonal perovskite compound crystal grains having a major axis D of 1 μm to 6 μm in at least one cross section perpendicular to the layer thickness direction.

6. 6. The solar cell according to claim 1, wherein the light absorption layer has perovskite compound crystal grains having a major axis D of 1 μm to 4 μm in at least one cross section perpendicular to a layer thickness direction thereof, the perovskite compound crystal grains having an N-sided polygon, where N is a positive integer greater than 5.

7. 7. The solar cell according to claim 1, wherein the light absorbing layer includes perovskite compound crystal grains penetrating the light absorbing layer in at least one cross section in the layer thickness direction.

8. 8. The solar cell according to claim 7, wherein a ratio of the perovskite compound crystal grains penetrating the light absorbing layer to the total number of crystal grains in the light absorbing layer is 50% to 90%.

9. 9. The solar cell according to claim 7, wherein a ratio of the perovskite compound crystal grains penetrating the light absorbing layer to the total number of crystal grains in the light absorbing layer is 60% to 85%.

10. 10. The solar cell according to claim 7, wherein the perovskite compound crystal grains include primary crystal grains and secondary crystal grains, and the number of the secondary crystal grains accounts for 80% to 100% of the total number of the perovskite compound crystal grains.

11. 11. The solar cell according to claim 7, wherein the perovskite compound crystal grains include primary crystal grains and secondary crystal grains, and the number of the secondary crystal grains accounts for 65% to 95% of the total number of the perovskite compound crystal grains.

12. The solar cell includes a first carrier transport layer and a second carrier transport layer, and the solar cell includes:

12. The solar cell according to claim 7, further comprising a passivation layer between the light absorbing layer and the first carrier transporting layer, and / or a passivation layer between the light absorbing layer and the second carrier transporting layer, wherein the passivation layer is used to reduce defects when two interfaces come into contact.

13. A method for manufacturing a solar cell, comprising producing a light absorbing layer containing a plurality of perovskite compound crystal grains according to any one of claims 1 to 12 in a non-contact sealed annealing vessel, wherein the light absorbing layer has a number cumulative distribution rate of perovskite compound crystal grains having a major axis D of 1 μm to 6 μm of ≧90% in at least one cross section perpendicular to the layer thickness direction. How solar cells are manufactured.

14. 1) the closed annealing vessel contains an annealing atmosphere, the annealing atmosphere contains a polar aprotic solvent, optionally the polar aprotic solvent contains at least one of N,N-dimethylformamide, 1-methyl-2-pyrrolidone, dimethyl sulfoxide, and dimethylacetamide; 2) the annealing temperature in the closed annealing vessel is 100 to 180°C; 3) The annealing time in the closed annealing container is 8 to 30 minutes; The method of claim 13, comprising one or more of the following conditions:

15. A solar cell module comprising the solar cell according to any one of claims 1 to 12 or the solar cell manufactured by the manufacturing method according to claim 13 or 14.

16. 16. An electrical device comprising the solar cell module of claim 15, wherein the solar cell module is used to provide electrical energy.

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