Molecular bridge organic matter, hole transport material, photovoltaic device and preparation method thereof, and photovoltaic system

Abstract

The embodiment of the invention provides a molecular bridge organic matter, a hole transport material, a photovoltaic device, a preparation method and a photovoltaic system. Amino groups or cyano groups in the molecular bridge organic matter can be combined with lead iodine octahedrons in the perovskite light absorption layer, phosphate groups, carboxylic acid groups, sulfonic acid groups, thiol groups or hydroxamic acid groups contained in the molecules serve as anchoring groups and can be combined with metal oxides of the first electronic layer, the perovskite light absorption layer and the metal oxides are bridged, and the perovskite light absorption layer is formed. And the hole transmission capability is improved.

Description

Technical Field

[0001] The present application relates to the technical field of solar cells, and in particular to a molecular bridge organic substance, a hole transport material, a photovoltaic device and a preparation method, and a photovoltaic system. Background Art

[0002] Perovskite solar cells (PSCs) have high photoelectric conversion efficiency, abundant material sources, and simple preparation processes. Currently, most high-efficiency single-cell and stacked solar cells use self-assembled monolayer (SAM) materials as hole transport materials. The bonding strength and contact density of the end groups of the SAM molecules with the upper and lower interfaces determine the device performance and stability of the prepared PSCs. However, the currently used SAM materials still have problems with poor wettability and low bonding strength. In addition, the perovskite light-absorbing layer is prone to produce a large number of charged defects at the lower interface and grain boundaries during the preparation process. These defects will become the center of non-radiative recombination, reducing the device performance and stability of PSCs.

[0003] It should be noted that the above content is not necessarily prior art, nor is it intended to limit the scope of patent protection of this application. Summary of the invention

[0004] The embodiments of the present application provide a molecular bridge organic substance, a hole transport material, a photovoltaic device and a preparation method, and a photovoltaic system to solve or alleviate one or more of the technical problems raised above.

[0005] The first aspect of the embodiment of the present application provides a molecular bridge organic compound, characterized in that the structure of the molecular bridge organic compound is as shown in formula (I):

[0006]

[0007] Among them, R1 is selected from phosphate, carboxylic acid, sulfonic acid, thiol, and hydroxamic acid; R2 and R3 are independently selected from non-existent or an alkyl chain with 1-8 carbon atoms; R4 is selected from amine or cyano; R5 is selected from non-existent, an oxygen atom, a sulfur atom, or a secondary methyl group.

[0008] Optionally, the structural formula of formula (1) is:

[0009]

[0010]

[0011] A second aspect of the embodiments of the present application provides a hole transport material, comprising at least one molecular bridge organic compound provided in the first aspect of the embodiments of the present application.

[0012] A third aspect of an embodiment of the present application provides a photovoltaic device, comprising at least a first electrode layer, a hole transport layer, a perovskite light absorption layer, an electron transport layer and a second electrode layer arranged in a stacked manner, wherein the material of the hole transport layer is selected from at least one of the hole transport materials provided in the second aspect of the embodiment of the present application.

[0013] Optionally, the first electrode layer and the second electrode layer are independently selected from at least one of indium tin oxide, indium zinc oxide, zinc aluminum oxide, silver nanowires, gold, silver, copper, aluminum, and carbon.

[0014] Optionally, the perovskite light-absorbing layer material is an ABX3 type perovskite material, wherein the A ion is at least one of cesium ion, rubidium ion, potassium ion, methylamine ion, formamidine ion, methylenediamine ion, benzamidine cation, and guanidinium cation, the B ion is at least one of divalent lead ion or divalent tin ion, and X is at least one of fluoride ion, chloride ion, bromide ion, iodide ion, thiocyanate ion, tetrafluoroborate ion, hexafluorophosphate ion, formate ion, or acetate ion.

[0015] A fourth aspect of the embodiments of the present application provides a method for preparing a photovoltaic device, comprising the following steps:

[0016] preparing a hole transport material solution;

[0017] Preparing a hole transport layer on the first electrode layer, wherein the hole transport layer is prepared from the hole transport material solution;

[0018] Preparing a perovskite light absorbing layer on the hole transport layer;

[0019] preparing an electron transport layer on the perovskite light absorbing layer;

[0020] A second electrode layer is formed on the electron transport layer.

[0021] Optionally, the solute of the hole transport material solution is at least one of the molecular bridge organic substances, and the solvent of the hole transport material solution is one of ethanol, isopropanol, chlorobenzene, toluene, ethyl acetate, chloroform, tetrahydrofuran, N,N-dimethylformamide or a mixed solvent.

[0022] Optionally, the concentration of the hole transport material solution is 0.1 mg-10 mg / mL.

[0023] A fifth aspect of the embodiments of the present application provides a photovoltaic system, which includes the photovoltaic device provided in the third aspect of the embodiments of the present application.

[0024] The above technical solution adopted in the embodiment of the present application may have the following advantages:

[0025] In the embodiment of the present application, a molecular bridge organic compound is provided as a new self-assembled monolayer material, and the material is used to prepare a hole transport layer, such as Figure 1 As shown, the amine group or cyanide group in the molecular bridge organic matter can combine with the lead iodine octahedron in the perovskite light-absorbing layer, and the phosphate group, carboxylic acid group, sulfonic acid group, thiol group or hydroxamic acid group contained in the molecule can act as an anchoring group, which can combine with the metal oxide of the first electron layer, bridge the perovskite and the metal oxide, and improve the hole transport capacity; at the same time, the amine group or cyanide group can passivate the defects on the lower interface of the perovskite, improve the crystallization quality of the perovskite, enhance the interface stability, and improve the working stability of the device; secondly, the introduction of the amine group or cyanide group enhances the interaction between the perovskite and the hole transport material, reduces the contact angle, and improves the wettability of the perovskite layer to the hole transport layer, which is beneficial to the preparation of large-area perovskite components. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the multiple drawings represent the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings only depict some embodiments disclosed in the present application and should not be regarded as limiting the scope of the present application.

[0027] Figure 1 It is a mechanism diagram of the present invention;

[0028] Figure 2 is a schematic structural diagram of a photovoltaic device provided by an embodiment of the present invention;

[0029] Figure 3 A schematic diagram of the process of preparing a photovoltaic device provided in an embodiment of the present application.

[0030] Description of reference numerals:

[0031] 101, first electrode layer; 102, hole transport layer; 103, perovskite light absorption layer; 104, electron transport layer; 105, second electrode layer. DETAILED DESCRIPTION

[0032] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings. In the accompanying drawings, for clarity, the sizes of layers, regions, elements and their relative sizes may be exaggerated. Wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limitations on the present application. It should be noted that, in the absence of conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

[0033] It should be understood that when an element or layer is referred to as "on ...", "adjacent to ...", "connected to" or "coupled to" other elements or layers, it can be directly on, adjacent to, connected to or coupled to other elements or layers, or there can be intervening elements or layers. On the contrary, when an element is referred to as "directly on ...", "directly adjacent to ...", "directly connected to" or "directly coupled to" other elements or layers, there is no intervening element or layer. It should be understood that although the terms first, second, third, etc. can be used to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or part from another element, component, region, layer or part. Therefore, without departing from the teachings of the present disclosure, the first element, component, region, layer or part discussed below can be represented as the second element, component, region, layer or part. And when the second element, component, region, layer or part is discussed, it does not mean that the present disclosure necessarily has the first element, component, region, layer or part.

[0034] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0035] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein, for example. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0036] To facilitate those skilled in the art to understand the technical solutions provided in the embodiments of the present application, the relevant technologies are described below:

[0037] The inventors have learned that using SAM materials as hole transport materials still has the problems of poor wettability and low bonding strength. In addition, the perovskite film layer is prone to generate a large number of charged defects at the lower interface and grain boundary during the preparation process. These defects will become the center of non-radiative recombination, reducing the device performance and stability of PSCs.

[0038] To this end, the embodiments of the present application provide a molecular bridge organic matter, a hole transport material, a photovoltaic device and a preparation method, and a technical solution for a photovoltaic system. Based on this, it is possible to improve the hole transport capability, improve the performance of optical devices, enhance interface stability, improve the working stability of devices, improve the wettability of the perovskite layer to the hole transport layer, and facilitate the preparation of large-area perovskite components. See below for details.

[0039] Hereinafter, exemplary embodiments according to the present application will be described in more detail with reference to the accompanying drawings. It should be noted that these exemplary embodiments can be implemented in many different forms and should not be construed as being limited to the embodiments described herein.

[0040] The first aspect of the present application provides a molecular bridge organic compound. The structure of the molecular bridge organic compound is shown in formula (I):

[0041]

[0042] Wherein, R1 is selected from phosphate, carboxylic acid, sulfonic acid, thiol, hydroxamic acid; R2 and R3 are independently selected from non-existent or alkyl chains with 1-8 carbon atoms; R4 is selected from amine or cyano; R5 is selected from non-existent, oxygen, sulfur or secondary methyl. Specifically, R2 is non-existent or R2 is selected from alkyl chains with 1-8 carbon atoms, and similarly, R3 is non-existent or R3 is selected from alkyl chains with 1-8 carbon atoms.

[0043] For example, the molecular bridge organic compound may be F1, F2, F3, F4, F5 or F6.

[0044]

[0045] When the molecular bridge organic compound is used as a new self-assembled monolayer material for preparing a hole transport layer, the amine group or cyano group in the molecular bridge organic compound can combine with the lead iodine octahedron in the perovskite light-absorbing layer, and the phosphate group, carboxylic acid group, sulfonic acid group, thiol group or hydroxamic acid group contained in the molecule can serve as an anchoring group and can combine with the metal oxide of the first electron layer to bridge the perovskite and the metal oxide, thereby improving the hole transport capacity; at the same time, the amine group or cyano group can passivate the defects on the lower interface of the perovskite, improve the crystallization quality of the perovskite, and enhance the interface stability; secondly, the introduction of the amine group or cyano group enhances the interaction between the perovskite and the hole transport material, reduces the contact angle, and improves the wettability of the perovskite layer to the hole transport layer.

[0046] The second aspect of the embodiment of the present application further provides a hole transport material, which includes at least one molecular bridge organic compound provided in the first aspect of the embodiment of the present application. Specifically, the hole transport material can be a molecular bridge organic compound, such as F1, or a mixture of two or more molecular bridge organic compounds, such as a mixture of F1 and F2.

[0047] The third aspect of the embodiments of the present application also provides a photovoltaic device, which includes at least a first electrode layer, a hole transport layer, a perovskite light absorption layer, an electron transport layer and a second electrode layer arranged in a stacked manner, and the material of the hole transport layer is selected from at least one of the hole transport materials provided in the second aspect of the embodiments of the present application.

[0048] Optionally, the first electrode layer and the second electrode layer are independently selected from at least one of indium tin oxide, indium zinc oxide, aluminum zinc oxide, silver nanowires, gold, silver, copper, aluminum, and carbon.

[0049] Optionally, the perovskite light-absorbing layer material is an ABX3 type perovskite material, wherein the A ion is at least one of cesium ion, rubidium ion, potassium ion, methylamine ion, formamidine ion, methylenediamine ion, benzamidine cation, and guanidinium cation, the B ion is at least one of divalent lead ion or divalent tin ion, and X is at least one of fluoride ion, chloride ion, bromide ion, iodide ion, thiocyanate ion, tetrafluoroborate ion, hexafluorophosphate ion, formate ion, or acetate ion.

[0050] Optionally, the electron transport layer is at least one of tin dioxide, titanium dioxide, [6,6]-phenyl-C71-butyric acid isomethyl ester, C60 or a C60 derivative.

[0051] A fourth aspect of the application embodiment provides a Figure 2 The method for preparing the photovoltaic device shown in Figure 3 As shown, the following steps are included:

[0052] Step 100: preparing a hole transport material solution;

[0053] Step 200: preparing a hole transport layer on the first electrode layer, wherein the hole transport layer is prepared from the hole transport material solution;

[0054] Step 300: preparing a perovskite light absorbing layer on the hole transport layer;

[0055] Step 400: preparing an electron transport layer on the perovskite light absorbing layer;

[0056] Step 500: preparing a second electrode layer on the electron transport layer.

[0057] Optionally, the solute of the hole transport material solution is at least one of the molecular bridge organic substances, and the solvent of the hole transport material solution is one of ethanol, isopropanol, chlorobenzene, toluene, ethyl acetate, chloroform, tetrahydrofuran, N,N-dimethylformamide or a mixed solvent.

[0058] Optionally, the concentration of the hole transport material solution is 0.1-10 mg / mL. For example, the concentration of the hole transport layer solution can be 0.1 mg / mL, 0.5 mg / mL, 1 mg / mL, 2 mg / mL, 4 mg / mL, 6 mg / mL, 8 mg / mL, 10 mg / mL. In some embodiments, the photovoltaic device includes a perovskite cell. The perovskite cell is a single-layer cell or a stacked cell; when it is a stacked cell, it is preferably any one of a perovskite / crystalline silicon stacked cell, a full perovskite stacked cell, a perovskite / organic stacked cell, and a perovskite / copper indium gallium selenide (CIGS) stacked cell.

[0059] In the following examples and comparative examples, raw materials not otherwise specified are all commercially available products; operating steps and operating parameters not otherwise specified are all reasonably selectable by those skilled in the art based on experiments.

[0060] [Example 1]

[0061] The present invention provides a method for preparing a solar cell, comprising the following steps:

[0062] S1, spin-coat 0.5 mg / mL F1 solution on a clean indium tin oxide (ITO) transparent conductive substrate at 4000 rpm for 30 seconds, and place the ITO glass with the F1 solution on a hot stage for annealing at 100 °C for 10 minutes to form a hole transport layer;

[0063] S2, dissolving 622.36 mg of lead iodide, 10.73 mg of iodomethylamine, 17.53 mg of cesium iodide, and 208.94 mg of iodomethylamine perovskite material in 1 mL of a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide (4:1 v:v), and stirring at room temperature until completely dissolved to obtain a perovskite precursor solution;

[0064] S3, in a nitrogen glove box, take 70uL of perovskite precursor solution and drop it onto the clean ITO conductive glass, spin-coat at 500rpm and 4000rpm for 2s and 40s respectively, slowly drop 400uL of anisole at 25s, then place the ITO glass on a hot stage and heat and anneal at 150℃ for 15min to form a perovskite light-absorbing layer;

[0065] S4, transfer the ITO conductive glass with the perovskite light absorbing layer to the vacuum coating instrument, and wait until the vacuum degree is 3*10 -4 C60 was evaporated at 1.5 Pa with a thickness of 30 nm to obtain an electron transport layer;

[0066] S5, transfer the ITO conductive glass with the hole transport layer, perovskite layer and electron transport layer to the glove box, scrape out the negative electrode area, and then transfer it to the vacuum coating instrument, and wait until the vacuum degree is 6*10 -4 A silver electrode was evaporated at 100 nm to form a silver electrode with a thickness of 100 nm, thereby obtaining a second electrode layer.

[0067] [Example 2]

[0068] The preparation method of Example 2 is substantially the same as that of Example 1, except that F1 is replaced by F2.

[0069] [Example 3]

[0070] The preparation method of Example 3 is substantially the same as that of Example 1, except that F1 is replaced by F3.

[0071] [Example 4]

[0072] The preparation method of Example 4 is substantially the same as that of Example 1, except that F1 is replaced by F4.

[0073] [Example 5]

[0074] The preparation method of Example 5 is substantially the same as that of Example 1, except that F1 is replaced by F5.

[0075] [Example 6]

[0076] The preparation method of Example 6 is substantially the same as that of Example 1, except that F1 is replaced by F6.

[0077] [Comparative Example]

[0078] The preparation method of the comparative example is substantially the same as that of Example 1, except that F1 is replaced by [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphoric acid.

[0079] The perovskite solar cells obtained in Examples 1 to 6 and the comparative example were tested using a simulated light source system, and the relevant performance test results are shown in Table 1.

[0080]

[0081] Table 1

[0082] As shown in Table 1, the open circuit voltage (V OC ), current density (J SC ), filling factor (FF) and photoelectric conversion efficiency (PCE) are significantly higher than those of the perovskite solar cell control group not prepared by the method provided by the present invention. By comparing the test results of Example 1 and Example 2, it can be concluded that the molecular bridge organic compound contains a cyano group, which can significantly improve the filling factor of the perovskite solar cell. By comparing the results of Example 1, Example 3 and Example 4, it can be seen that the filling factor of the solar cell prepared by the perovskite bridge organic compound containing a carboxyl group or a sulfonic acid group is improved relative to the solar cell prepared by the molecular bridge organic compound containing a phosphate group. By comparing Examples 1 to 6, the solar cell prepared by the molecular bridge organic compound (F6) in which R1 is a phosphate group, R4 is a cyano group; and R5 is a sulfur atom has the most obvious improvement effect, thanks to the amino group or The cyanide group can combine with the lead iodine octahedron in the perovskite light-absorbing layer. The phosphate group, carboxylic acid group, sulfonic acid group, thiol group or hydroxamic acid group contained in the molecule can act as an anchoring group and can combine with the metal oxide of the first electron layer, bridge the perovskite and the metal oxide, and improve the hole transport capacity; at the same time, the amine group or cyanide group can passivate the defects on the lower interface of the perovskite, improve the crystallization quality of the perovskite, enhance the interface stability, and improve the working stability of the device; secondly, the introduction of the amine group or cyanide group enhances the interaction between the perovskite and the hole transport material, reduces the contact angle, and improves the wettability of the perovskite layer to the hole transport layer, which is beneficial to the preparation of large-area perovskite components.

[0083] The fifth aspect of the embodiment of the present application provides a photovoltaic system, including the photovoltaic device in any of the above embodiments. The advantages of the above photovoltaic devices are also possessed by the photovoltaic system, which will not be repeated here. The above photovoltaic system has a wide range of applications, not only limited to photovoltaic power stations, such as ground power stations, rooftop power stations and water power stations, but also includes various equipment and devices that use solar energy to generate electricity, such as user solar power supplies, solar street lights, solar cars and solar buildings. Of course, it can be understood that the application scenarios of the photovoltaic system are not limited to this, that is to say, the photovoltaic system can be used in all fields where solar energy is required for power generation. Taking the photovoltaic power generation system network as an example, the photovoltaic system may include a photovoltaic array, a junction box and an inverter. The photovoltaic array may be an array combination of multiple photovoltaic devices. For example, multiple photovoltaic devices can form multiple photovoltaic arrays. The photovoltaic array is connected to the junction box. The junction box can converge the current generated by the photovoltaic array. The converged current flows through the inverter and is converted into the alternating current required by the mains power grid and then connected to the mains network to realize solar power supply.

[0084] It should be noted that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. The orientation words "inside" and "outside" refer to the inside and outside relative to the outline of each component itself. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Therefore, the exemplary term "above..." can include both "above..." and "below..." orientations. The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used here are interpreted accordingly.

[0085] It should also be noted that "one embodiment", "another embodiment", "embodiment", etc. mentioned in this application refer to the specific features, structures or characteristics described in conjunction with the embodiment included in at least one embodiment generally described in this application. The same expression appearing in multiple places in the specification does not necessarily refer to the same embodiment. Further, when a specific feature, structure or characteristic is described in conjunction with any embodiment, it is claimed that the realization of such feature, structure or characteristic in conjunction with other embodiments also falls within the scope of this application.

[0086] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0087] It should also be noted that the above are only preferred embodiments of the present application, and the patent protection scope of the present application is not limited thereto. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A molecular bridge organic compound, characterized in that: The structure of the molecular bridge organic compound is shown in formula (I): Among them, R1 is selected from phosphate, carboxylic acid, sulfonic acid, thiol, and hydroxamic acid; R2 and R3 are independently selected from non-existent or an alkyl chain with 1-8 carbon atoms; R4 is selected from amine or cyano; R5 is selected from non-existent, an oxygen atom, a sulfur atom, or a secondary methyl group.

2. The molecular bridge organic compound according to claim 1, characterized in that: The structural formula of formula (1) includes:

3. A hole transport material, characterized in that: The method comprises at least one molecular bridge organic compound as claimed in claim 1 or 2.

4. A photovoltaic device, characterized in that: The method comprises at least a first electrode layer, a hole transport layer, a perovskite light absorbing layer, an electron transport layer and a second electrode layer which are stacked, wherein the material of the hole transport layer is selected from at least one of the hole transport materials described in claim 3.

5. The photovoltaic device according to claim 4, characterized in that: The first electrode layer and the second electrode layer are independently selected from at least one of indium tin oxide, indium zinc oxide, zinc aluminum oxide, silver nanowires, gold, silver, copper, aluminum, and carbon.

6. The photovoltaic device according to claim 4, characterized in that: The perovskite light-absorbing layer material is an ABX3 type perovskite material, wherein the A ion is at least one of cesium ion, rubidium ion, potassium ion, methylamine ion, formamidine ion, methylenediamine ion, benzamidine cation, and guanidinium cation, the B ion is at least one of divalent lead ion or divalent tin ion, and X is at least one of fluoride ion, chloride ion, bromide ion, iodide ion, thiocyanate ion, tetrafluoroborate ion, hexafluorophosphate ion, formate ion, or acetate ion.

7. The photovoltaic device according to claim 4, characterized in that: The electron transport layer is at least one of tin dioxide, titanium dioxide, [6,6]-phenyl-C71-butyric acid isomethyl ester, C60 or a C60 derivative.

8. A method for preparing a photovoltaic device according to any one of claims 4 to 7, characterized in that: The following steps are involved: Preparing a hole transport material solution from the hole transport material according to claim 3; Preparing a hole transport layer on the first electrode layer, wherein the hole transport layer is prepared from the hole transport material solution; Preparing a perovskite light absorbing layer on the hole transport layer; preparing an electron transport layer on the perovskite light absorbing layer; A second electrode layer is formed on the electron transport layer.

9. The preparation method according to claim 8, characterized in that: The solute of the hole transport material solution is at least one of the molecular bridge organic substances, and the solvent of the hole transport material solution is one of ethanol, isopropanol, chlorobenzene, toluene, ethyl acetate, chloroform, tetrahydrofuran, N,N-dimethylformamide or a mixed solvent.

10. The preparation method according to claim 9, characterized in that: The concentration of the hole transport material solution is 0.1-10 mg / mL.

11. A photovoltaic system, characterized in that: The photovoltaic system comprises the photovoltaic device according to any one of claims 4 to 7.

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