Photoelectric device, preparation method thereof and photovoltaic module

Abstract

The invention relates to a photoelectric device, a preparation method thereof and a photovoltaic module. The photoelectric device comprises a substrate layer, a first photoelectric conversion layer arranged on the substrate layer and a band gap regulation and control layer arranged on the side, away from the substrate layer, of the first photoelectric conversion layer. Wherein the thermal expansion coefficient of the band gap regulation and control layer is at least 4.5 times of that of the first photoelectric conversion layer; or the thermal expansion coefficient of the band gap regulation and control layer is smaller than that of the first photoelectric conversion layer. The band gap regulation and control layer is arranged on the side, away from the substrate layer, of the first photoelectric conversion layer, so that the band gap of the first photoelectric conversion layer can be regulated and controlled when the composition of the photoelectric conversion layer does not need to be adjusted, and the photoelectric performance of the photoelectric device is improved.

Description

Technical Field

[0001] This application relates to the field of optoelectronics, and in particular to optoelectronic devices and their fabrication methods, and photovoltaic modules. Background Technology

[0002] Optoelectronic devices are devices that convert light signals into electrical signals using the photoelectric effect, such as solar cells. With the development of photovoltaic technology, the efficiency of single-junction devices has gradually approached the Shockley-Quesser efficiency limit (approximately 33%). To overcome this limit, tandem solar cells are an effective method. A tandem cell is a photovoltaic device formed by stacking multiple semiconductor materials with different band gaps together. This structure allows the cell to more effectively absorb and convert different parts of the solar spectrum, thereby improving the overall energy conversion efficiency.

[0003] In tandem solar cells, it is typically necessary to adjust the bandgap of different sub-cells to achieve current matching. For example, in a perovskite / perovskite / silicon triple-junction tandem solar cell, since the bandgap of the silicon cell is fixed at approximately 1.12 eV, achieving current matching requires a bandgap of approximately 1.4 eV for the middle perovskite layer and approximately 1.9 eV for the top perovskite layer. To optimize the bandgap of the perovskite layer and improve current matching, traditional techniques usually involve adjusting the composition of the perovskite layer. However, this leads to new stability issues, which in turn affect the performance of the tandem solar cell. Summary of the Invention

[0004] Based on this, some embodiments of this application provide an optoelectronic device and a method for fabricating the same, which can control the band gap of the optoelectronic conversion layer and improve the optoelectronic performance of the optoelectronic device without adjusting the composition of the optoelectronic conversion layer.

[0005] In addition, some other embodiments of this application also provide a photovoltaic module including the above-described optoelectronic devices.

[0006] An optoelectronic device includes a substrate layer, a first photoelectric conversion layer disposed on the substrate layer, and a bandgap modulation layer disposed on the side of the first photoelectric conversion layer away from the substrate layer.

[0007] Wherein, the thermal expansion coefficient of the bandgap control layer is at least 4.5 times that of the thermal expansion coefficient of the first photoelectric conversion layer; or, the thermal expansion coefficient of the bandgap control layer is less than that of the first photoelectric conversion layer.

[0008] In some embodiments, the coefficient of thermal expansion of the bandgap control layer is at least 5 times that of the coefficient of thermal expansion of the first photoelectric conversion layer; optionally, the coefficient of thermal expansion of the bandgap control layer is 5 to 10 times that of the coefficient of thermal expansion of the first photoelectric conversion layer.

[0009] Optionally, the coefficient of thermal expansion of the bandgap control layer is 1×10⁻⁶.-5 1 / K~3.5×10 -4 1 / K.

[0010] In some embodiments, the bandgap modulation layer includes a polymer substrate and a conductive material dispersed in the polymer substrate. The polymer substrate includes one or two of polydimethylsiloxane and polyurethane. The conductive material includes one or more of silver nanowires, poly(3,4-ethylenedioxythiophene-polystyrene sulfonate), polypyrrole, zinc oxide, titanium oxide, and carbon nanotubes.

[0011] In some embodiments, the bandgap control layer comprises polydimethylsiloxane and silver nanowires, polypyrrole, titanium dioxide, or carbon nanotubes dispersed in the polydimethylsiloxane; or, the bandgap control layer comprises polyurethane and poly(3,4-ethylenedioxythiophene-polystyrene sulfonate) or zinc oxide dispersed in the polyurethane; and / or,

[0012] The conductive material accounts for 2% to 7% of the total mass of the conductive material and the polymer substrate.

[0013] In some embodiments, the thermal expansion coefficient of the bandgap modulation layer is smaller than that of the first photoelectric conversion layer, and the thermal expansion coefficient of the bandgap modulation layer is 1×10⁻⁶. -7 1 / K ~1×10 -6 1 / K;

[0014] Optionally, the material of the bandgap modulation layer includes SiO2 and SiN. x One or more of Al2O3, TiO2 and SnO2.

[0015] In some embodiments, the thickness of the bandgap control layer is 10 nm to 30 nm.

[0016] In some embodiments, the first photoelectric conversion layer is a perovskite layer with a band gap of 1.4 eV to 1.6 eV.

[0017] In some embodiments, the thickness of the first photoelectric conversion layer is 600 nm to 1000 nm; and / or,

[0018] The material of the first photoelectric conversion layer is ABX3, where A includes FA. + MA + Cs + and Rb + One or more of them, B including Pb 2+ and Sn 2+ One or two of them, X includes I - ,Br - Cl- SCN - and OCN - One or more of them.

[0019] In some embodiments, the optoelectronic device includes a first sub-cell, a second sub-cell and a third sub-cell disposed on both sides of the first sub-cell, the first sub-cell including a first photoelectric conversion layer and the bandgap control layer, and the second sub-cell including the substrate layer;

[0020] Optionally, the band gap of the second sub-cell is 1.12eV~1.3eV, and the band gap of the third sub-cell is 1.7eV~2.1eV.

[0021] In some embodiments, the second sub-cell is a crystalline silicon cell; optionally, the second sub-cell includes one of a tunneling oxide passivated contact cell, a heterojunction cell, and an interdigitated back contact cell; and / or,

[0022] The third sub-cell is a perovskite cell.

[0023] A method for fabricating an optoelectronic device includes the following steps:

[0024] A first photoelectric conversion layer is formed on the substrate layer;

[0025] A bandgap modulation layer is formed on the side of the first photoelectric conversion layer away from the substrate layer;

[0026] Wherein, the thermal expansion coefficient of the bandgap control layer is at least 4.5 times that of the thermal expansion coefficient of the first photoelectric conversion layer; or, the thermal expansion coefficient of the bandgap control layer is less than that of the first photoelectric conversion layer.

[0027] In some embodiments, the bandgap control layer is prepared using a solution method;

[0028] Optionally, a solution containing a bandgap control material is coated onto the first photoelectric conversion layer and annealed to prepare the bandgap control layer.

[0029] In some embodiments, a solution containing bandgap modulation is spin-coated onto the first photoelectric conversion layer; optionally, spin-coating is first performed at a speed of 1000 rpm to 2000 rpm for 10 s to 25 s, followed by spin-coating at a speed of 3000 rpm to 5000 rpm for 30 s to 50 s; and / or,

[0030] The annealing temperature is 80℃~100℃, and the time is 20min~40min.

[0031] A photovoltaic module includes the above-described optoelectronic device or an optoelectronic device prepared by the above-described preparation method.

[0032] The optoelectronic device of some embodiments of this application includes a substrate layer, a first photoelectric conversion layer disposed on the substrate layer, and a bandgap control layer disposed on the side of the first photoelectric conversion layer away from the substrate layer. When the optoelectronic device is working, the temperature continuously rises due to stimulation from light, electricity, heat, etc. The thermal expansion coefficient of the bandgap control layer differs significantly from that of the first photoelectric conversion layer. When the temperature changes, the bandgap control layer applies tensile or compressive stress to the first photoelectric conversion layer through interfacial shear force to control the bandgap. When the temperature recovers, the stress is released, thereby adjusting the bandgap without adjusting the composition of the first photoelectric conversion layer, thus ensuring stability. However, if the bandgap control layer is disposed between the first photoelectric conversion layer and the substrate layer, and the bandgap control layer is prepared first and then the first photoelectric conversion layer is formed during the fabrication process, the interaction force between the first photoelectric conversion layer and the bandgap control layer is strong. During the operation of the optoelectronic device, the bandgap control layer is prone to damaging the first photoelectric conversion layer, thus failing to achieve the function of adjusting the bandgap.

[0033] Therefore, in some embodiments of the optoelectronic device of this application, by providing a bandgap control layer on the side of the first photoelectric conversion layer away from the substrate layer, the bandgap of the first photoelectric conversion layer can be controlled without adjusting the composition of the photoelectric conversion layer, thereby improving the photoelectric performance of the optoelectronic device. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 This is a schematic diagram of the structure of an optoelectronic device according to some embodiments of this application;

[0036] Figure 2 This is a schematic diagram of the structure of an optoelectronic device according to other embodiments of this application;

[0037] Figure 3 This is a schematic diagram of a process flow for fabricating optoelectronic devices according to some embodiments of this application;

[0038] Figure 4 The graphs show the relationship between current density and voltage of the solar cells in Embodiment 1 and Comparative Example 1 of this application.

[0039] Figure 5 This is a graph showing the relationship between the external quantum efficiency and wavelength of the solar cells of Embodiment 1 and Comparative Example 1 of this application.

[0040] Explanation of reference numerals in the attached figures:

[0041] Figure 1 In the middle, there is a substrate layer 110, a first photoelectric conversion layer 120, and a bandgap modulation layer 130;

[0042] Figure 2 In the diagram, there are a first electrode 01, a second hole transport layer 02, a silicon substrate 03, a second electron transport layer 04, a first composite layer 05, a first hole transport layer 06, a first perovskite layer 07, a bandgap modulation layer 14, a first electron transport layer 08, a second composite layer 09, a third hole transport layer 10, a second perovskite layer 11, a third electron transport layer 12, and a second electrode 13. Detailed Implementation

[0043] To facilitate understanding of this application, a more comprehensive description of the application will be provided below in conjunction with specific embodiments. Preferred embodiments of the application are given in the specific embodiments. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this application.

[0044] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0045] Unless otherwise stated or in case of conflict, the terms or phrases used in this application shall have the following meanings:

[0046] In this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" and "second" may explicitly or implicitly include at least one of those features.

[0047] In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise expressly and specifically limited.

[0048] In this application, "one or more" refers to any one, two, or more of the listed items. "Multiple" refers to any two or more of the listed items.

[0049] Unless otherwise specified, all percentage concentrations mentioned in this application refer to the final concentration. The final concentration refers to the proportion of the added component in the system after the addition of that component.

[0050] In this application, terms such as "further," "even more," "particularly," "for example," "like," "example," and "exemplary" are used for descriptive purposes to indicate a connection in the coverage of different technical solutions presented earlier and later, but should not be construed as limiting the preceding technical solution or restricting the scope of protection herein. Unless otherwise specified herein, A (e.g., B) indicates that B is a non-limiting example of A, and it can be understood that A is not limited to B.

[0051] In this application, "optionally," "optionally," and "optional" mean that something is optional, that is, it is selected from either "present" or "absent." If multiple "options" appear in a technical solution, unless otherwise specified and there are no contradictions or mutual constraints, each "option" is independent. In this application, descriptions such as "optionally contains" and "optionally includes" indicate "contains or does not contain." "Optional component X" indicates whether component X exists or does not exist, or whether component X is contained or not.

[0052] When a numerical range is disclosed in this application, the range is considered continuous and includes the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to an integer, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be merged. In other words, unless otherwise specified, all ranges disclosed in this application should be understood to include any and all subranges to which they are included.

[0053] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0054] The terms "comprising" and "having," and any variations thereof, used in the embodiments of this application, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or components inherent to such processes, methods, products, or devices.

[0055] In this application, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this application can be combined with other embodiments.

[0056] In the flowchart of this application, although the steps are shown sequentially according to the arrows, these steps are not necessarily performed in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps. They can be executed in other orders. Moreover, at least some of the steps in the diagram may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times. Their execution order is not necessarily sequential, but can be performed alternately or in turn with at least some of other steps or other sub-steps or stages.

[0057] The first aspect of this application provides an optoelectronic device; please refer to [link / reference]. Figure 1 It includes a substrate 110, a first photoelectric conversion layer 120 disposed on the substrate 110, and a bandgap control layer 130 disposed on the side of the first photoelectric conversion layer 120 away from the substrate 110.

[0058] The thermal expansion coefficient of the bandgap control layer 130 is at least 4.5 times that of the thermal expansion coefficient of the first photoelectric conversion layer 120; or, the thermal expansion coefficient of the bandgap control layer 130 is less than that of the first photoelectric conversion layer 120.

[0059] The optoelectronic device of some embodiments of this application includes a substrate 110, a first photoelectric conversion layer 120 disposed on the substrate 110, and a bandgap control layer 130 disposed on the side of the first photoelectric conversion layer 120 away from the substrate 110. When the optoelectronic device is working, the temperature rises continuously due to stimulation by light, electricity, heat, etc. The thermal expansion coefficient of the bandgap control layer 130 is significantly different from that of the first photoelectric conversion layer 120. When the temperature changes, the bandgap control layer 130 applies tensile or compressive stress to the first photoelectric conversion layer 120 through interfacial shear force to control the bandgap. When the temperature recovers, the stress is released, thereby adjusting the bandgap without adjusting the composition of the first photoelectric conversion layer 120, which can ensure stability. Furthermore, if the bandgap control layer 130 is disposed between the first photoelectric conversion layer 120 and the substrate layer 110, during the fabrication process, the bandgap control layer 130 is fabricated first, and then the first photoelectric conversion layer 120 is formed. The interaction force between the first photoelectric conversion layer 120 and the bandgap control layer 130 is relatively strong. When the optoelectronic device is working, the bandgap control layer 130 is prone to damage to the first photoelectric conversion layer 120, and cannot play the role of adjusting the bandgap.

[0060] Therefore, in some embodiments of the optoelectronic device of this application, by providing a bandgap control layer 130 on the side of the first photoelectric conversion layer 120 away from the substrate layer 110, the bandgap of the first photoelectric conversion layer 120 can be controlled without adjusting the composition of the photoelectric conversion layer, thereby improving the optoelectronic performance of the optoelectronic device.

[0061] In some embodiments, the coefficient of thermal expansion of the bandgap control layer is at least 5 times that of the coefficient of thermal expansion of the first photoelectric conversion layer. Optionally, the coefficient of thermal expansion of the bandgap control layer is 5 to 10 times that of the first photoelectric conversion layer. For example, the coefficient of thermal expansion of the bandgap control layer is 4.5 times, 5 times, 5.25 times, 5.5 times, 6 times, 7 times, 8 times, 9 times, 10 times, or any combination of these values. A large ratio between the coefficient of thermal expansion of the bandgap control layer and the coefficient of thermal expansion of the first photoelectric conversion layer, for example, greater than 10:1, results in significant changes in the bandgap control layer during the operation of the optoelectronic device, which can easily affect the performance of the first photoelectric conversion layer. Therefore, in some embodiments of this application, the coefficient of thermal expansion of the bandgap control layer is 5 to 10 times that of the first photoelectric conversion layer. Optionally, the coefficient of thermal expansion of the bandgap control layer is 4.5 to 5.5 times that of the first photoelectric conversion layer. Optionally, the thermal expansion coefficient of the bandgap control layer is 5 to 5.5 times that of the thermal expansion coefficient of the first photoelectric conversion layer.

[0062] In some embodiments, the coefficient of thermal expansion of the bandgap control layer is 1×10⁻⁶. -5 1 / K ~3.5×10 -4 1 / K. For example, the coefficient of thermal expansion of the bandgap control layer can be, but is not limited to, 10. -5 1 / K, 2×10 -5 1 / K, 4×10 -5 1 / K, 6×10 -5 1 / K, 6×10 -5 1 / K, 1×10 -4 1 / K, 1.2×10 -4 1 / K, 1.4×10 -4 1 / K, 1.5×10 -4 1 / K, 2×10 -4 1 / K, 2.5×10 -4 1 / K, 3×10 -4 1 / K, 3.5×10 -4 1 / K or a range consisting of any two of these values.

[0063] Specifically, the bandgap modulation layer comprises a substrate and a conductive material dispersed in the polymer substrate. The polymer substrate includes one or both of polydimethylsiloxane (PDMS) and polyurethane (PU); the conductive material includes one or more of silver nanowires (Ag NWs), poly(3,4-ethylenedioxythiophene-polystyrene sulfonate) (PEDOT:PSS), polypyrrole (PPy), zinc oxide, titanium oxide, and carbon nanotubes (CNTs). The polymer substrate provides a high coefficient of thermal expansion, and the conductive material improves conductivity. Together, they enable the bandgap modulation layer to possess both a high coefficient of thermal expansion and good conductivity. During the operation of the optoelectronic device, this introduces tensile stress into the first photoelectric conversion layer, thereby reducing the bandgap of the first photoelectric conversion layer.

[0064] Specifically, the percentage of conductive material in the total mass of the conductive material and polymer substrate is 2% to 7%. For example, the percentage of conductive material in the total mass of the conductive material and polymer substrate can be, but is not limited to, 2%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, or any combination of these values. If the percentage of conductive material in the total mass of the conductive material and polymer substrate is small, for example, less than 3%, the conductivity of the bandgap control layer is weak, leading to an increase in series resistance; if the percentage of conductive material in the total mass of the conductive material and polymer substrate is large, for example, greater than 7%, the coefficient of thermal expansion of the bandgap control layer is low, resulting in a weaker bandgap adjustment effect on the first photoelectric conversion layer. In one embodiment, the percentage of conductive material in the total mass of the conductive material and polymer substrate is 2% to 5%.

[0065] In some embodiments, the bandgap control layer comprises polydimethylsiloxane and silver nanowires, polypyrrole, titanium dioxide, or carbon nanotubes dispersed in the polydimethylsiloxane, respectively denoted as silver nanowires / polydimethylsiloxane (Ag NWs / PDMS), polypyrrole / polydimethylsiloxane (PPy / PDMS), titanium dioxide / polydimethylsiloxane (TiO2 / PDMS), and carbon nanotubes / polydimethylsiloxane (CNTs / PDMS); or, the bandgap control layer comprises polyurethane and poly(3,4-ethylenedioxythiophene-polystyrene sulfonate) or zinc oxide dispersed in the polyurethane, respectively denoted as poly(3,4-ethylenedioxythiophene-polystyrene sulfonate) / polyurethane (PEDOT:PSS / PU) and zinc oxide / polyurethane (ZnO / PU). It is understood that in this application, "silver nanowires / polydimethylsiloxane" represents a composite material of silver nanowires and polydimethylsiloxane; similarly, the " / " in other materials has the same meaning and will not be elaborated further.

[0066] Specifically, the coefficient of thermal expansion of silver nanowires / polydimethylsiloxane (Ag NWs / PDMS) is 2 × 10⁻⁶. -5 1 / K ~1×10 -4The coefficient of thermal expansion of 1 / K poly(3,4-ethylenedioxythiophene-polystyrene sulfonate / polyurethane) (PEDOT:PSS / PU) is 5×10⁻⁶. -5 1 / K ~1.5×10 -4 The coefficient of thermal expansion of polypyrrole / polydimethylsiloxane (PPy / PDMS) is 1 × 10⁻⁶ K. -5 1 / K ~9×10 -5 The coefficient of thermal expansion of zinc oxide / polyurethane (ZnO / PU) is 2 × 10⁻⁶ K. -5 1 / K ~8×10 -5 The coefficient of thermal expansion of titanium dioxide / polydimethylsiloxane (TiO2 / PDMS) is 5 × 10⁻⁶ K. -5 1 / K ~1×10 -4 The coefficient of thermal expansion of carbon nanotubes / polydimethylsiloxane (CNTs / PDMS) is 3 × 10¹⁰ K. -5 1 / K ~1×10 -4 1 / K.

[0067] Specifically, the coefficient of thermal expansion of the first photoelectric conversion layer is 1×10⁻⁶. -6 1 / K ~5×10 -5 1 / K.

[0068] In other embodiments, the coefficient of thermal expansion of the bandgap control layer is smaller than that of the first photoelectric conversion layer. When the optoelectronic device is working, its temperature continuously rises due to stimulation from light, electricity, and heat. Because the coefficient of thermal expansion of the bandgap control layer is smaller than that of the first photoelectric conversion layer, the bandgap control layer applies compressive stress to the first photoelectric conversion layer through interfacial shear force during temperature changes, thereby increasing the bandgap of the first photoelectric conversion layer. This stress is released when the temperature recovers, thus increasing the bandgap during operation without needing to adjust the composition of the first photoelectric conversion layer. Specifically, the coefficient of thermal expansion of the bandgap control layer is 1 × 10⁻⁶. -7 1 / K ~1×10 -6 1 / K.

[0069] Optionally, the material of the bandgap tuning layer includes SiO2 and SiN. x One or more of Al2O3, TiO2, and SnO2. The aforementioned bandgap modulation layer can introduce compressive stress into the first photoelectric conversion layer when the optoelectronic device is working, thereby increasing the bandgap of the first photoelectric conversion layer.

[0070] In some embodiments, the thickness of the bandgap modulation layer is 10 nm to 30 nm. For example, the thickness of the bandgap modulation layer can be, but is not limited to, 10 nm, 12 nm, 15 nm, 18 nm, 20 nm, 22 nm, 25 nm, 28 nm, 30 nm, or any combination of these values. A thinner bandgap modulation layer, for example, less than 10 nm, results in less stress applied to the first photoelectric conversion layer during operation of the optoelectronic device, leading to a smaller bandgap change in the first photoelectric conversion layer. Conversely, a thicker bandgap modulation layer, for example, greater than 30 nm, reduces the amount of sunlight received by the first photoelectric conversion layer, affecting photoelectric performance. Furthermore, the conductivity of the bandgap modulation layer is relatively poor, and excessive thickness increases the series resistance. Therefore, in some embodiments of this application, the thickness of the bandgap modulation layer is 10 nm to 30 nm. Optionally, the thickness of the bandgap modulation layer is 10 nm to 20 nm.

[0071] In some embodiments, the first photoelectric conversion layer is a perovskite layer with a bandgap of 1.4 eV to 1.6 eV, and the thermal expansion coefficient of the bandgap modulation layer is at least 5 times that of the first photoelectric conversion layer. This configuration helps to reduce the bandgap of the perovskite layer, improving current matching and thus enhancing the photoelectric performance of the cell when applied in a perovskite / perovskite / silicon triple-junction tandem solar cell.

[0072] Specifically, the thickness of the first photoelectric conversion layer is 600nm to 1000nm. For example, the thickness of the first photoelectric conversion layer may be, but is not limited to, 600nm, 650nm, 700nm, 750nm, 800nm, 850nm, 900nm, 950nm, 1000nm, or any combination of these values.

[0073] In some embodiments, the material of the first photoelectric conversion layer is ABX3, wherein A includes FA. + MA + Cs + and Rb + One or more of them, B including Pb 2+ and Sn 2+ One or two of them, X includes I - ,Br - Cl - SCN - and OCN - One or more of them.

[0074] It is understood that in other embodiments, the first photoelectric conversion layer is not limited to a perovskite layer, but may also be other photoelectric conversion layers that require bandgap adjustment.

[0075] In some embodiments, the optoelectronic device has a single-junction structure, the substrate layer includes a first electrode, and the optoelectronic device further includes a second electrode disposed on the side of the bandgap modulation layer away from the first photoelectric conversion layer.

[0076] Specifically, the materials of the first electrode and the second electrode each independently include one or more of transparent conductive oxides, conductive polymers, and metal electrodes. Specifically, the transparent conductive oxide includes one or more of indium tin oxide (ITO), fluorine-doped tin oxide (FTO), and indium zinc oxide (IZO). The metal electrode includes one or both of Ag and Au.

[0077] Specifically, the thickness of the first electrode and the second electrode are each independently between 100 nm and 1000 nm. For example, the thickness of the first electrode and the second electrode can be, but is not limited to, 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1000 nm, or any combination of these values.

[0078] In some embodiments, a first carrier transport layer and a second carrier transport layer are further provided between the first electrode and the first photoelectric conversion layer, and between the bandgap modulation layer and the second electrode, respectively. One of the first carrier transport layer and the second carrier transport layer is a hole transport layer, and the other is an electron transport layer. In this case, the optoelectronic device includes a first electrode, a first carrier transport layer, a first photoelectric conversion layer, a bandgap modulation layer, a second carrier transport layer, and a second electrode, which are sequentially stacked.

[0079] Specifically, the material of the hole transport layer includes, but is not limited to, one or more of organic small molecule materials and inorganic materials. Specifically, the organic small molecule materials include one or more of poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), cyclopentadithiophene derivatives (HTM-1), and cyclopentadithiophene methoxy derivatives (HTM-2), and the inorganic materials include NiO. x And one or two of CuO.

[0080] Specifically, the thickness of the hole transport layer is 1 nm to 50 nm. For example, the thickness of the hole transport layer may be, but is not limited to, 1 nm, 5 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, or any combination of these values.

[0081] Specifically, the materials of the electron transport layer include, but are not limited to, one or more of TiO2, SnO2 and ZnO.

[0082] Specifically, the thickness of the electron transport layer is 5 nm to 50 nm. For example, the thickness of the electron transport layer may be, but is not limited to, 5 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, or any combination of these values.

[0083] In other embodiments, the optoelectronic device is a stacked structure. Specifically, the optoelectronic device is a triple-junction stacked solar cell, including a first sub-cell and a second and third sub-cell disposed on both sides of the first sub-cell. The first sub-cell includes a first photoelectric conversion layer and a bandgap modulation layer, and the second sub-cell includes a substrate layer.

[0084] Specifically, the band gap of the first sub-cell is larger than that of the second sub-cell, and the band gap of the first sub-cell is smaller than that of the third sub-cell.

[0085] Specifically, the band gap of the second sub-cell is 1.12eV~1.3eV, and the band gap of the third sub-cell is 1.7eV~2.1eV.

[0086] Although tandem solar cells present greater research and manufacturing challenges than single-junction solar cells, higher conversion efficiency remains the future direction for solar cell development. Tandem solar cell technology is particularly popular in space applications because it can provide higher power output within a given area, which is crucial for satellites and other space-based equipment. Furthermore, with future technological advancements, tandem solar cells will see wider application in terrestrial photovoltaics and other fields. The optoelectronic devices employing some embodiments of this application can improve the bandgap of the photoelectric conversion layer during operation, thereby improving the current matching of the optoelectronic device, enhancing the conversion efficiency of the tandem solar cell, and increasing the repeatability of the device, laying a foundation for the research and application of tandem devices.

[0087] Specifically, the second sub-cell is a crystalline silicon cell. Optionally, the second sub-cell includes one of a tunneling oxide passivated contact cell (TOPCon cell), a heterojunction cell (HJT cell), and an interdigitated back contact cell (IBC cell).

[0088] In some embodiments, the second sub-cell includes a substrate layer, a second electron transport layer disposed on the side of the substrate layer facing the first sub-cell, a second hole transport layer disposed on the side of the substrate layer away from the first sub-cell, and a first electrode. Specifically, the substrate layer is a silicon substrate.

[0089] Specifically, the thickness of the silicon substrate in the crystalline silicon bottom cell is 80μm to 180μm. For example, the thickness of the silicon substrate may be, but is not limited to, 80μm, 90μm, 100μm, 120μm, 140μm, 150μm, 160μm, 180μm or any combination of these values.

[0090] Specifically, the third sub-cell is a perovskite cell.

[0091] Specifically, the first sub-cell includes a first hole transport layer, a first photoelectric conversion layer, a bandgap modulation layer and a first electron transport layer that are sequentially stacked on the second sub-cell;

[0092] The third sub-cell includes a second hole transport layer, a third photoelectric conversion layer, a third electron transport layer, and a second electrode, which are sequentially stacked on the first sub-cell.

[0093] Optionally, a first composite layer is provided between the first sub-cell and the second sub-cell, and a second composite layer is provided between the first sub-cell and the third sub-cell.

[0094] In some embodiments, the band gap of the third photoelectric conversion layer is 1.7 eV to 2.1 eV. For example, the band gap of the third photoelectric conversion layer may be, but is not limited to, 1.7 eV, 1.8 eV, 1.9 eV, 2 eV, 2.1 eV, or any combination of these values.

[0095] In some embodiments, the thickness of the third photoelectric conversion layer is 300 nm to 600 nm. For example, the thickness of the third photoelectric conversion layer may be, but is not limited to, 300 nm, 350 nm, 400 nm, 450 nm, 500 nm, 550 nm, 600 nm, or any combination of these values.

[0096] In some embodiments, the material of the third photoelectric conversion layer is ABX3, where A is FA. + MA + Cs + and Rb + One or more of them, where B is Pb 2+ and Sn 2+ One or two of them, X is I - ,Br - Cl - SCN - and OCN - One or more of them.

[0097] In some embodiments, the materials of the first electrode and the second electrode each independently include one or more of a transparent conductive oxide, a conductive polymer, and a metal electrode. Specifically, the transparent conductive oxide includes one or more of ITO, FTO, and IZO. The metal electrode includes one or both of Ag and Au.

[0098] In some embodiments, the thickness of the first electrode and the second electrode are each independently between 100 nm and 1000 nm. For example, the thickness of the first electrode and the second electrode may be, but is not limited to, 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1000 nm, or any combination of these values.

[0099] In some embodiments, the materials of the first hole transport layer, the second hole transport layer, and the third hole transport layer independently include, but are not limited to, one or more of organic small molecule materials and inorganic materials. Specifically, the organic small molecule materials include one or more of PTAA, HTM-1, and HTM-2, and the inorganic materials include one or two of NiOx and CuO.

[0100] In some embodiments, the thicknesses of the first hole transport layer, the second hole transport layer, and the third hole transport layer are independently 1 nm to 50 nm. For example, the thicknesses of the first hole transport layer, the second hole transport layer, and the third hole transport layer may each be independently, but not limited to, 1 nm, 5 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, or any combination of these values.

[0101] In some embodiments, the materials of the first electron transport layer, the second electron transport layer, and the third electron transport layer are independently including, but not limited to, one or more of TiO2, SnO2, and ZnO.

[0102] In some embodiments, the thicknesses of the first electron transport layer, the second electron transport layer, and the third electron transport layer are independently 5 nm to 50 nm. For example, the thicknesses of the first electron transport layer, the second electron transport layer, and the third electron transport layer may be, but are not limited to, 5 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, or any combination of these values.

[0103] In some embodiments, the materials of the first composite layer and the second composite layer independently comprise transparent conductive oxides. Specifically, the materials of the first composite layer and the second composite layer independently comprise one or more of ITO, FTO, and IZO.

[0104] Specifically, the thickness of the first composite layer and the second composite layer is independently between 10 nm and 50 nm. For example, the thickness of the first composite layer and the second composite layer can be independently, but is not limited to, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, or any combination of these values.

[0105] As the number of sub-cells increases, the theoretical conversion efficiency of tandem solar cells gradually rises. However, the fabrication difficulty and process complexity of the devices also increase significantly. Triple-junction tandem solar cells offer a good balance between process complexity and conversion efficiency, highlighting the importance of researching them. The most common type of triple-junction tandem solar cell is the perovskite / perovskite / silicon triple-junction tandem cell. For perovskite / perovskite / silicon triple-junction tandem cells, since the bandgap of silicon cells is fixed at approximately 1.12 eV, achieving current matching requires a bandgap of approximately 1.4 eV for the middle perovskite layer and approximately 1.9 eV for the top perovskite layer. However, to achieve a bandgap of around 1.4 eV for the middle bandgap perovskite layer, Sn needs to be introduced into the perovskite composition. 2+ This will severely affect the crystallization and stability of perovskite. For wide-bandgap perovskite layers, to achieve a bandgap of around 1.9 eV, a large amount of Br needs to be introduced into the perovskite composition. - However, the iodine / bromine mixed perovskite composition undergoes significant phase separation under conditions such as illumination, which severely affects device performance. For perovskite / perovskite / silicon triple-junction tandem solar cells, current research mainly focuses on suppressing phase separation in the wide-bandgap perovskite layer, primarily by adjusting the perovskite layer composition, for example, using OCN... - Partially replaces Br in wide-bandgap perovskites - This suppresses phase separation while reducing nonradiative recombination. Alternatively, introducing rubidium ions into wide-bandgap perovskites can increase lattice distortion, thereby suppressing phase separation. However, this introduces new stability issues.

[0106] In some embodiments of this application, by introducing a bandgap control layer on top of the intermediate perovskite layer, the bandgap control layer introduces tensile stress on the intermediate perovskite layer when the temperature rises during the operation of the optoelectronic device. The tensile stress can effectively reduce the bandgap, thereby reducing the bandgap of the intermediate perovskite layer during operation, thus matching the current and improving the photoelectric conversion efficiency of the optoelectronic device. This provides a new way to adjust the bandgap without adjusting the composition of the perovskite layer and can maintain stability.

[0107] Furthermore, in perovskite / perovskite / silicon triple-junction tandem solar cells, since the sub-cells are fabricated sequentially, the bottom cell is used as the substrate when fabricating the top cell. Therefore, various solutions and annealing processes may damage the bottom cell during the fabrication of the top cell. In some embodiments of this application, by setting a bandgap control layer on top of the first photoelectric conversion layer, the damage to the first photoelectric conversion layer during the fabrication of the top cell can be reduced to a certain extent.

[0108] In some embodiments, please refer to Figure 2The optoelectronic device includes a first electrode 01, a second hole transport layer 02, a silicon substrate 03, a second electron transport layer 04, a first composite layer 05, a first hole transport layer 06, a first perovskite layer 07, a bandgap modulation layer 14, a first electron transport layer 08, a second composite layer 09, a third hole transport layer 10, a second perovskite layer 11, a third electron transport layer 12, and a second electrode 13, stacked sequentially. The first electrode 01, the second hole transport layer 02, the silicon substrate 03, and the second electron transport layer 04 constitute the second sub-cell, i.e., the bottom cell. The first hole transport layer 06, the first perovskite layer 07, the bandgap modulation layer 14, and the first electron transport layer 08 constitute the first sub-cell, i.e., the middle cell. The third hole transport layer 10, the second perovskite layer 11, and the third electron transport layer 12 constitute the third sub-cell, i.e., the top cell.

[0109] It is understood that the optoelectronic devices in some embodiments of this application are not limited to perovskite / perovskite / silicon triple junction tandem cells, and are also applicable to other situations where bandgap adjustment is required.

[0110] In addition, in this application, the optoelectronic device is not limited to a solar cell, but can also be other optoelectronic devices that require bandgap adjustment, such as light-emitting diodes.

[0111] The second aspect of this application provides a method for fabricating an optoelectronic device; please refer to [link to relevant documentation]. Figure 3 It includes the following steps:

[0112] Step S110: Form a first photoelectric conversion layer on the substrate layer.

[0113] Step S120: A bandgap modulation layer is formed on the side of the first photoelectric conversion layer away from the substrate layer.

[0114] The thermal expansion coefficient of the bandgap control layer is at least 4.5 times that of the thermal expansion coefficient of the first photoelectric conversion layer; or the thermal expansion coefficient of the bandgap control layer is less than that of the first photoelectric conversion layer.

[0115] In some embodiments, the bandgap control layer is prepared using a solution method.

[0116] Specifically, a solution containing a bandgap control material is coated onto the first photoelectric conversion layer and then annealed to prepare the bandgap control layer.

[0117] Specifically, a solution containing a bandgap control material is spin-coated onto the first photoelectric conversion layer. In one example, the spin-coating is first performed at a speed of 1000 rpm to 2000 rpm for 10 to 25 seconds, followed by spin-coating at a speed of 3000 rpm to 5000 rpm for 30 to 50 seconds. This method facilitates uniform coating of the solution onto the surface of the first photoelectric conversion layer.

[0118] Specifically, the bandgap control materials are as described in the first aspect above, and will not be repeated here.

[0119] Specifically, the annealing temperature is 80℃~100℃, and the time is 20min~40min.

[0120] Specifically, the preparation steps of the first photoelectric conversion layer can be those commonly used in the field, such as solution preparation. There are no particular limitations here, and they will not be elaborated further.

[0121] In some embodiments, the optoelectronic device is a stacked battery, including a first sub-cell and a second and a third sub-cell disposed on both sides of the first sub-cell. The first sub-cell includes a first photoelectric conversion layer and a bandgap control layer. The second sub-cell includes a substrate layer. The bandgap of the second photoelectric conversion layer is 1.12 eV to 1.3 eV. The third sub-cell includes a third photoelectric conversion layer. The bandgap of the third photoelectric conversion layer is 1.7 eV to 2.1 eV.

[0122] Specifically, the second sub-cell is a crystalline silicon cell. Optionally, the second sub-cell includes one of a tunneling oxide passivated contact cell (TOPCon cell), a heterojunction cell (HJT cell), and an interdigitated back contact cell (IBC cell).

[0123] Specifically, the third sub-cell is a perovskite cell.

[0124] Specifically, the first sub-cell includes a first hole transport layer, a first photoelectric conversion layer, a bandgap modulation layer and a first electron transport layer that are sequentially stacked on the second sub-cell;

[0125] The third sub-cell includes a second hole transport layer, a third photoelectric conversion layer, a third electron transport layer, and a second electrode, which are sequentially stacked on the first sub-cell.

[0126] Optionally, a first composite layer is provided between the first sub-cell and the second sub-cell, and a second composite layer is provided between the first sub-cell and the third sub-cell.

[0127] Specifically, the fabrication steps for each layer can be those commonly used in the field, and there are no particular limitations here. For example, each hole transport layer can be fabricated using solution methods or magnetron sputtering. Each electron transport layer can be fabricated using vapor deposition or atomic layer deposition. Each composite layer can be fabricated using magnetron sputtering. Each electrode can be fabricated using vapor deposition, etc.

[0128] A third aspect of this application provides a photovoltaic module, including the optoelectronic device described in the first aspect or the optoelectronic device prepared by the preparation method described in the second aspect.

[0129] In some embodiments, the photovoltaic module further includes an encapsulation structure for encapsulating optoelectronic devices. Specifically, the encapsulation structure includes an encapsulating film and a cover plate. The encapsulating film covers the surface of the optoelectronic device, and the cover plate covers the surface of the encapsulating film away from the optoelectronic device.

[0130] In one embodiment, the photovoltaic module includes: a first cover plate, a first encapsulating film, a photoelectric device, a second encapsulating film, and a second cover plate, which are stacked sequentially.

[0131] It is understood that the encapsulation films and covers can be those commonly used in the field, and no special limitations are made here.

[0132] To make the objectives and advantages of this application clearer, the optoelectronic device and its effects are further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are only for explaining this application and should not be used to limit this application. Unless otherwise specified, the following embodiments do not include components other than unavoidable impurities. Unless otherwise specified, the drugs and instruments used in the embodiments are conventional choices in the art. Experimental methods in the embodiments that do not specify specific conditions are implemented according to conventional conditions, such as those described in literature, books, or methods recommended by the manufacturer.

[0133] Example 1

[0134] This embodiment provides a solar cell; please refer to [link / reference]. Figure 2 The battery comprises, in sequence, a first electrode 01, a second hole transport layer 02, a silicon substrate 03, a second electron transport layer 04, a first composite layer 05, a first hole transport layer 06, a first perovskite layer 07, a bandgap control layer 14, a first electron transport layer 08, a second composite layer 09, a third hole transport layer 10, a second perovskite layer 11, a third electron transport layer 12, and a second electrode 13. The first electrode 01, the second hole transport layer 02, the silicon substrate 03, and the second electron transport layer 04 constitute the second sub-cell, i.e., the bottom cell. The first hole transport layer 06, the first perovskite layer 07, the bandgap control layer 14, and the first electron transport layer 08 constitute the first sub-cell, i.e., the middle cell. The third hole transport layer 10, the second perovskite layer 11, and the third electron transport layer 12 constitute the third sub-cell, i.e., the top cell.

[0135] The method for fabricating the solar cell in this embodiment includes the following steps:

[0136] (1) An n-type c-Si wafer with a bulk resistivity of 1.5 ± 0.5 Ω·cm was used as the silicon substrate O3. First, the silicon substrate O3 was processed in a dilute KOH solution, then subjected to standard RCA cleaning, and then etched with dilute hydrofluoric acid (HF) to remove the oxide layer formed on the wafer surface. Then, PECVD (plasma chemical vapor deposition) was used to deposit (i)a-Si:H / (n)μc-SiOx:H (intrinsic hydrogenated amorphous silicon layer / n-type hydrogenated microcrystalline silicon oxide layer) with thicknesses of 80 nm and 150 nm on the front side as the second electron transport layer O4, and (i)a-Si:H / (p)μc-Si:H (intrinsic hydrogenated amorphous silicon layer / p-type hydrogenated microcrystalline silicon layer) with thicknesses of 50 nm and 120 nm on the other side as the second hole transport layer O2. Subsequently, 15 nm and 30 nm thick ITO conductive layers were deposited on the front and back sides of the silicon wafer, respectively, using radio frequency magnetron sputtering. The ITO conductive layer on the front side served as the first composite layer 05. Finally, a layer of silver paste was printed on the back side of the wafer, and the resulting cell was cured in an oven at 165°C. The ITO conductive layer on the back side and the silver electrode together constituted the first electrode 01.

[0137] (2) The SAM solution (MeO-2PACz:2PACz mass ratio of 3:1, solvent of ethanol, total concentration of 0.5mg / mL) was spin-coated at 4000 rpm for 30s, and then annealed at 100℃ for 10 minutes to obtain the first hole transport layer 06 with a thickness of 2nm.

[0138] (3) Mid-band gap perovskite (FA) 0.98 MA 0.02 ) 0.95 Cs 0.05 Pb(I 0.98 Br 0.02 )3 was dissolved in a mixed solution of DMF:DMSO = 4:1 (volume ratio) to obtain a concentration of 1.7 mol / L. Then, spin-coating was performed with the following parameters: first, spin-coating at 2000 rpm for 25 s, then at 5000 rpm for 30 s. 200 μL of chlorobenzene was added dropwise 10 s before the end of spin-coating. After spin-coating, the mixture was annealed at 100℃ for 20 minutes to obtain the first perovskite layer 07, with a thickness of 1 μm and a coefficient of thermal expansion of 4 × 10⁻⁶. -5 1 / K.

[0139] (4) The Ag NWs dispersion (concentration of 0.5 mg / mL, solvent of ethanol) and PDMS prepolymer (PDMS:toluene = 1:3, volume ratio) were thoroughly mixed, wherein the mass percentage of Ag NWs was 5%. The mixed solution was spin-coated onto the first perovskite layer 07. The spin-coating parameters were set to spin-coat at 1000 rpm for 10 s and then at 3000 rpm for 30 s. After spin-coating, the layer was annealed at 80 °C for 20 minutes to obtain a bandgap control layer 14 with a thickness of 20 nm and a coefficient of thermal expansion of 2 × 10⁻⁶. -4 1 / K.

[0140] (5) A 10 nm thick C layer is deposited on the bandgap control layer 14 by vacuum thermal evaporation. 60 Then, a 30 nm thick SnO2 layer was prepared using ALD. 60 Together with SnO2, they form the first electron transport layer 08. Then, a layer of IZO with a thickness of 20 nm is prepared by magnetron sputtering as the second composite layer 09.

[0141] (6) A NiO layer with a thickness of 15 nm was prepared on the second composite layer 09 by magnetron sputtering. x Then, the SAM solution (Meo-2PACz:2PACz = 3:1, solvent: ethanol, total concentration: 0.5 mg / mL) was spin-coated at 4000 rpm for 30 seconds, followed by annealing at 100°C for 10 minutes. NiO x Together with the SAM layer, it forms the third hole transport layer 10.

[0142] (7) Wide-bandgap perovskite FA 0.7 Cs 0.3 Pb(I 0.333 Br 0.667 3 was dissolved in a mixed solution of DMF:DMSO = 4:1, with a concentration of 1.0 mol / L. The spin-coating parameters were set as follows: spin-coating at 1000 rpm for 10 s, then spin-coating at 4000 rpm for 40 s. 160 μL of anisole was added dropwise 10 s before the end of spin-coating. The spin-coated sample was annealed at 100 °C for 20 min to obtain the second perovskite layer 11 with a thickness of 400 nm.

[0143] (8) A 10 nm thick C layer was deposited by vacuum thermal evaporation. 60 Then, a 30 nm thick SnO2 layer was prepared using ALD. 60 Together with SnO2, they form the third electron transport layer 12. A 20 nm thick layer of IZO is prepared by magnetron sputtering, and then a 400 nm thick layer of Ag is deposited by vacuum thermal evaporation. IZO and Ag together form the second electrode 13.

[0144] Example 2

[0145] This embodiment provides a perovskite solar cell, similar to the solar cell in Embodiment 1, except that the bandgap control layer is different. The fabrication steps of the bandgap control layer in this embodiment are as follows:

[0146] (4) The Ag NWs dispersion (concentration of 0.5 mg / mL, solvent of ethanol) and PDMS prepolymer (PDMS:toluene = 1:3, volume ratio) were thoroughly mixed, wherein the mass percentage of Ag NWs was 2%. The mixed solution was spin-coated onto the first perovskite layer 07. The spin-coating parameters were set to spin-coat at 1000 rpm for 10 s, then at 3000 rpm for 30 s. After spin-coating, the layer was annealed at 80 °C for 20 minutes to obtain a bandgap control layer 14 with a thickness of 20 nm and a coefficient of thermal expansion of 2.2 × 10⁻⁶. -4 1 / K.

[0147] Example 3

[0148] This embodiment provides a perovskite solar cell, similar to the solar cell in Embodiment 1, except that the bandgap control layer is different. The fabrication steps of the bandgap control layer in this embodiment are as follows:

[0149] (4) Ag NWs dispersion (concentration 0.5 mg / mL, solvent ethanol) and PDMS prepolymer (PDMS:toluene = 1:3, volume ratio) were thoroughly mixed, with Ag NWs mass percentage being 3.5%. The mixed solution was spin-coated onto the first perovskite layer 07. The spin-coating parameters were set to spin-coat at 1000 rpm for 10 s, then at 3000 rpm for 30 s. After spin-coating, the layer was annealed at 80 °C for 20 minutes to obtain a bandgap control layer 14 with a thickness of 20 nm and a coefficient of thermal expansion of 2.1 × 10⁻⁶. -4 1 / K.

[0150] Example 4

[0151] This embodiment provides a perovskite solar cell, similar to the solar cell in Embodiment 1, except that the bandgap control layer is different. The fabrication steps of the bandgap control layer in this embodiment are as follows:

[0152] (4) The Ag NWs dispersion (concentration of 0.5 mg / mL, solvent of ethanol) and PDMS prepolymer (PDMS:toluene = 1:3, volume ratio) were thoroughly mixed, wherein the mass percentage of Ag NWs was 7%. The mixed solution was spin-coated onto the first perovskite layer 07. The spin-coating parameters were set to spin-coat at 1000 rpm for 10 s and then at 3000 rpm for 30 s. After spin-coating, the layer was annealed at 80 °C for 20 minutes to obtain a bandgap control layer 14 with a thickness of 20 nm and a coefficient of thermal expansion of 1.8 × 10⁻⁶. -4 1 / K.

[0153] Example 5

[0154] This embodiment provides a perovskite solar cell, similar to the solar cell in Embodiment 1, except that the thickness of the bandgap control layer is different. The fabrication steps of the bandgap control layer in this embodiment are as follows:

[0155] (4) The Ag NWs dispersion (concentration of 0.5 mg / mL, solvent of ethanol) and PDMS prepolymer (PDMS:toluene = 1:3, volume ratio) were thoroughly mixed, wherein the mass percentage of Ag NWs was 5%. The mixed solution was spin-coated onto the first perovskite layer 07. The spin-coating parameters were set to spin-coat at 1000 rpm for 10 s and then at 2000 rpm for 30 s. After spin-coating, the layer was annealed at 80 °C for 20 minutes to obtain a bandgap control layer 14 with a thickness of 30 nm and a coefficient of thermal expansion of 2 × 10⁻⁶. -4 1 / K.

[0156] Comparative Example 1

[0157] Comparative Example 1 provides a solar cell similar to that of Example 1, except that it does not contain a bandgap modulation layer. The other layer structures are the same as those of Example 1 and will not be described again.

[0158] The preparation method of the solar cell in Comparative Example 1 is similar to that in Example 1, except that it does not contain step (4). The other steps are the same as in Example 1 and will not be repeated here.

[0159] Comparative Example 2

[0160] Comparative Example 2 provides a solar cell similar to that of Example 1, except that the bandgap control layer is different. The other layers are the same as in Example 1 and will not be described again.

[0161] The preparation method of the solar cell in Comparative Example 2 is similar to that in Example 1, except that step (4) is different. Step (4) of Comparative Example 2 is as follows:

[0162] Ag NWs dispersion (concentration 0.5 mg / mL, solvent: ethanol) was thoroughly mixed with PDMS prepolymer (PDMS:toluene = 1:3, volume ratio), wherein the mass percentage of Ag NWs was 30%. The mixed solution was spin-coated onto the first perovskite layer 07. The spin-coating parameters were set to spin-coat at 1000 rpm for 10 s, then at 3000 rpm for 30 s. After spin-coating, the layer was annealed at 80 °C for 20 minutes to obtain a bandgap control layer 14 with a thickness of 20 nm and a coefficient of thermal expansion of 9 × 10⁻⁶. -5 1 / K.

[0163] Comparative Example 3

[0164] Comparative Example 3 provides a solar cell similar to that of Example 1, except that the bandgap modulation layer is disposed at the bottom of the first perovskite layer. The other layers are the same as in Example 1 and will not be described further.

[0165] The preparation method of the solar cell in Comparative Example 3 is similar to that in Example 1, except that steps (3) and (4) are different. Steps (3) and (4) of Comparative Example 3 are as follows:

[0166] (3) Ag NWs dispersion (concentration 0.5 mg / mL, solvent ethanol) and PDMS prepolymer (PDMS:toluene = 1:3, volume ratio) were thoroughly mixed, wherein the mass percentage of Ag NWs was 5%. The mixed solution was spin-coated onto the first hole transport layer. The spin-coating parameters were set to spin-coat at 1000 rpm for 10 s and then at 3000 rpm for 30 s. After spin-coating, the layer was annealed at 80 °C for 20 minutes to obtain a bandgap control layer with a thickness of 20 nm and a coefficient of thermal expansion of 2 × 10⁻⁶. -4 1 / K.

[0167] (4) Mid-band gap perovskite (FA) 0.98 MA 0.02 ) 0.95 Cs 0.05 Pb(I 0.98 Br 0.02 3 was dissolved in a mixed solution of DMF:DMSO = 4:1 (volume ratio) to obtain a concentration of 1.7 mol / L. Then, it was spin-coated onto the bandgap control layer. The spin-coating parameters were set as follows: first, spin-coating at 2000 rpm for 25 s, then at 5000 rpm for 30 s. 200 μL of chlorobenzene was added dropwise 10 s before the end of the spin-coating. After spin-coating, the layer was annealed at 100℃ for 20 minutes to obtain the first perovskite layer with a thickness of 1 μm and a coefficient of thermal expansion of 4 × 10⁻⁶. -5 1 / K.

[0168] The performance of the batteries in the above embodiments and comparative examples was tested, and the results are shown in Table 1 below. Figure 4 and Figure 5 The experimental data shown. Figure 4 This is a graph showing the relationship between current density and voltage of the solar cells in Embodiment 1 and Comparative Example 1 of this application. Figure 4 In the diagram, the horizontal axis represents Voltage (V), with the unit being V, and the vertical axis represents Current density (mA / cm²). 2 () represents current density, unit mA / cm². 2 . Figure 5 This is a graph showing the relationship between the external quantum efficiency and wavelength of the solar cells in Embodiment 1 and Comparative Example 1 of this application. Figure 5 In the figure, the horizontal axis Wavelength (nm) represents the wavelength in nm, and the vertical axis EQE (%) represents the external quantum efficiency in %.

[0169] Table 1

[0170]

[0171] As can be seen from the comparison between Examples 1 to 5 and Comparative Example 1, the short-circuit current of Examples 1 to 5 is significantly higher than that of Comparative Example 1. This is a result of the decrease in the band gap of the mid-bandgap perovskite. In addition, the open-circuit voltage and fill factor of Examples 1 to 5 are also improved, and the photoelectric conversion efficiency is significantly improved compared with Comparative Example 1.

[0172] from Figure 5 As can be seen, the light absorption range of Example 1 is significantly wider, which indicates that the band gap of the perovskite solar cell is lower than that of Comparative Example 1. This is a result of the stress sandwich layer.

[0173] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0174] The embodiments described above are merely illustrative of several implementation methods of this application, intended to facilitate a detailed understanding of the technical solutions of this application, but should not be construed as limiting the scope of protection of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. It should be understood that technical solutions obtained by those skilled in the art based on the technical solutions provided in this application through logical analysis, reasoning, or limited experimentation are all within the scope of protection of the appended claims. Therefore, the scope of protection of this patent application should be determined by the content of the appended claims, and the specification and drawings can be used to interpret the content of the claims.

Claims

1. An optoelectronic device, characterized in that, It includes a substrate layer, a first photoelectric conversion layer disposed on the substrate layer, and a bandgap modulation layer disposed on the side of the first photoelectric conversion layer away from the substrate layer; Wherein, the thermal expansion coefficient of the bandgap control layer is at least 4.5 times that of the thermal expansion coefficient of the first photoelectric conversion layer; or, the thermal expansion coefficient of the bandgap control layer is less than that of the first photoelectric conversion layer.

2. The optoelectronic device according to claim 1, characterized in that, The thermal expansion coefficient of the bandgap control layer is at least 5 times that of the thermal expansion coefficient of the first photoelectric conversion layer; optionally, the thermal expansion coefficient of the bandgap control layer is 5 to 10 times that of the thermal expansion coefficient of the first photoelectric conversion layer. Optionally, the coefficient of thermal expansion of the bandgap control layer is 1×10⁻⁶. -5 1 / K~3.5×10 -4 1 / K.

3. The optoelectronic device according to claim 2, characterized in that, The bandgap control layer includes a polymer substrate and a conductive material dispersed in the polymer substrate. The polymer substrate includes one or two of polydimethylsiloxane and polyurethane. The conductive material includes one or more of silver nanowires, poly(3,4-ethylenedioxythiophene-polystyrene sulfonate), polypyrrole, zinc oxide, titanium oxide, and carbon nanotubes.

4. The optoelectronic device according to claim 3, characterized in that, The bandgap control layer comprises polydimethylsiloxane and silver nanowires, polypyrrole, titanium dioxide, or carbon nanotubes dispersed in the polydimethylsiloxane; or, the bandgap control layer comprises polyurethane and poly(3,4-ethylenedioxythiophene-polystyrene sulfonate) or zinc oxide dispersed in the polyurethane. And / or, The conductive material accounts for 2% to 7% of the total mass of the conductive material and the polymer substrate.

5. The optoelectronic device according to claim 1, characterized in that, The thermal expansion coefficient of the bandgap modulation layer is less than that of the first photoelectric conversion layer, and the thermal expansion coefficient of the bandgap modulation layer is 1×10⁻⁶. -7 1 / K~1×10 -6 1 / K; Optionally, the material of the bandgap modulation layer includes SiO2 and SiN. x One or more of Al2O3, TiO2 and SnO2.

6. The optoelectronic device according to any one of claims 1 to 5, characterized in that, The thickness of the bandgap control layer is 10nm~30nm.

7. The optoelectronic device according to any one of claims 1 to 4, characterized in that, The first photoelectric conversion layer is a perovskite layer with a band gap of 1.4 eV to 1.6 eV.

8. The optoelectronic device according to claim 7, characterized in that, The thickness of the first photoelectric conversion layer is 600nm~1000nm; and / or, The material of the first photoelectric conversion layer is ABX3, where A includes FA. + MA + Cs + and Rb + One or more of them, B including Pb 2+ and Sn 2+ One or two of them, X includes I - ,Br - Cl - SCN - and OCN - One or more of them.

9. The optoelectronic device according to claim 7, characterized in that, The optoelectronic device includes a first sub-cell, a second sub-cell and a third sub-cell disposed on both sides of the first sub-cell. The first sub-cell includes a first photoelectric conversion layer and the bandgap control layer. The second sub-cell includes the substrate layer. Optionally, the band gap of the second sub-cell is 1.12eV~1.3eV, and the band gap of the third sub-cell is 1.7eV~2.1eV.

10. The optoelectronic device according to claim 9, characterized in that, The second sub-cell is a crystalline silicon cell. Optionally, the second sub-cell includes one of a tunneling oxide passivated contact cell, a heterojunction cell, and an interdigitated back contact cell; and / or, The third sub-cell is a perovskite cell.

11. A method for fabricating an optoelectronic device, characterized in that, Includes the following steps: A first photoelectric conversion layer is formed on the substrate layer; A bandgap modulation layer is formed on the side of the first photoelectric conversion layer away from the substrate layer; Wherein, the thermal expansion coefficient of the bandgap control layer is at least 4.5 times that of the thermal expansion coefficient of the first photoelectric conversion layer; or, the thermal expansion coefficient of the bandgap control layer is less than that of the first photoelectric conversion layer.

12. The method for fabricating the optoelectronic device according to claim 11, characterized in that, The bandgap control layer was prepared using a solution method. Optionally, a solution containing a bandgap control material is coated onto the first photoelectric conversion layer and annealed to prepare the bandgap control layer.

13. The method for fabricating the optoelectronic device according to claim 12, characterized in that, The solution containing bandgap modulation is applied to the first photoelectric conversion layer by spin coating; optionally, spin coating is first performed at a speed of 1000 rpm to 2000 rpm for 10 s to 25 s, and then at a speed of 3000 rpm to 5000 rpm for 30 s to 50 s; and / or, The annealing temperature is 80℃~100℃, and the time is 20min~40min.

14. A photovoltaic module, characterized in that, It includes the optoelectronic device according to any one of claims 1 to 10 or the optoelectronic device prepared by the preparation method according to any one of claims 11 to 13.

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