Solar cell and preparation method thereof

Abstract

The invention provides a solar cell and a preparation method thereof. The solar cell includes: a conductive substrate; the mesoporous electron transport layer is arranged on the conductive substrate; the mesoporous spacer layer is arranged on the mesoporous electron transport layer; the porous counter electrode layer is arranged on the mesoporous spacing layer; the perovskite layer is arranged in pore structures of the mesoporous electron transport layer, the mesoporous spacing layer and the porous counter electrode layer; wherein the mesoporous electron transport layer comprises a mesoporous electron transport skeleton and an interface modification layer, the interface modification layer is coated on the mesoporous surface of the mesoporous electron transport skeleton, and the material of the interface modification layer is an insulating oxide material. The interface modification layer is formed by the insulating oxide material and coats the mesoporous surface of the mesoporous electron transport skeleton, so that electrons can pass successfully, the effect of reducing charge recombination is achieved, and the effect of improving the efficiency of the device is achieved.

Description

Technical Field

[0001] The present invention relates to the field of solar cells, and in particular to a solar cell and a preparation method thereof. Background Art

[0002] Printable mesoscopic perovskite solar cells are based on a three-porous membrane structure, including mesoporous titanium dioxide (mp-TiO2), mesoporous zirconium dioxide (mp-ZrO2) and a porous carbon layer. The three-layer porous membrane structure is prepared by screen printing. The advantage of this device structure is that the perovskite has good contact with the carbon electrode, and the carriers can be better extracted, so the short-circuit current density of the device is guaranteed. The perovskite has good hole transport ability, and the structure without a hole transport layer avoids the device cost and stability problems caused by the hole transport layer, so that the device can be prepared and filled in the air. Mesoporous titanium dioxide acts as an electron transport layer to extract electrons, and the role of the interlayer zirconium dioxide is to prevent the mesoporous titanium dioxide layer from directly contacting the carbon electrode, resulting in carrier recombination.

[0003] Printable mesoscopic perovskite solar cells have broad commercial prospects due to their advantages such as easy large-scale manufacturing and low cost. However, compared with traditional planar perovskite solar cells, there is a large performance loss. Unlike planar perovskite solar cells, the separation of carriers in printable mesoscopic perovskite solar cells only occurs at the interface between perovskite and electron transport layer. Therefore, reducing the carrier interface recombination between perovskite and electron transport layer is crucial to improving the performance of printable mesoscopic perovskite solar cells. Summary of the invention

[0004] The present invention aims to solve the problem of carrier recombination at the interface between perovskite and electron transport layer to a certain extent, and improve the performance of solar cell devices. Printable mesoscopic perovskite solar cell devices usually need to be prepared by high-temperature sintering. The electron transport layer titanium oxide will produce a large number of oxygen vacancy defects during the sintering process under the influence of the sintering environment and sintering atmosphere. These oxygen defects easily capture electrons and non-radiatively recombine with holes in the perovskite, causing performance loss of the device. The present invention aims to wrap a layer of insulating oxide on the surface of titanium oxide, reduce the recombination loss caused by surface defects of titanium oxide, and improve the performance of printable mesoscopic perovskite solar cells.

[0005] Specifically, the present invention provides the following technical solutions:

[0006] In a first aspect of the present invention, a solar cell is provided, the solar cell comprising:

[0007] Conductive substrate;

[0008] A mesoporous electron transport layer, wherein the mesoporous electron transport layer is disposed on the conductive substrate;

[0009] A mesoporous spacer layer, wherein the mesoporous spacer layer is disposed on the mesoporous electron transport layer;

[0010] A porous counter electrode layer, wherein the porous counter electrode layer is disposed on the mesoporous spacer layer;

[0011] A perovskite layer, wherein the perovskite layer is disposed in the pore structure of the mesoporous electron transport layer, the mesoporous spacer layer and the porous counter electrode layer;

[0012] The mesoporous electron transport layer comprises a mesoporous electron transport skeleton and an interface modification layer, wherein the interface modification layer is coated on the mesoporous surface of the mesoporous electron transport skeleton, and the material of the interface modification layer is an insulating oxide material.

[0013] The provided solar cell can passivate the defects of the mesoporous electron transport skeleton, reduce recombination centers, reduce performance losses, and reduce charge recombination, thereby improving the efficiency of the device by coating the mesoporous surface of the mesoporous electron transport skeleton with an interface modification layer formed by an insulating oxide material.

[0014] According to an embodiment of the present invention, the solar cell described above may further include the following additional technical features:

[0015] According to an embodiment of the present invention, the material of the interface modification layer is selected from at least one of MgO, Al2O3, SiO2, and La2O3. These materials can be used as insulating oxide materials to form an interface modification layer, thereby reducing the effect of charge recombination and improving the efficiency of the device. According to a specific embodiment, the material of the interface modification layer is SiO2.

[0016] According to an embodiment of the present invention, the thickness of the interface modification layer is 0.1-15 nm. The thickness of the interface modification layer is maintained at a certain thickness, which can take into account both device efficiency and barrier effect. When the thickness of the interface modification layer is relatively thick, due to the effect of insulation, the interface resistance will be large, and the carriers cannot be effectively separated, thereby causing serious interface recombination and decreased device efficiency. However, if the thickness is too low, the barrier effect is poor, and it cannot be effectively blocked, and the modification effect is not obvious.

[0017] According to an embodiment of the present invention, the mesoporous electron transport skeleton is a mesoporous TiO2 layer.

[0018] According to an embodiment of the present invention, the mesoporous spacer layer is a zirconium oxide layer.

[0019] The porous counter electrode layer is a porous carbon electrode layer.

[0020] A second aspect of the present invention provides a method for preparing a solar cell, the method comprising the following steps:

[0021] Providing a conductive substrate, the conductive substrate comprising a substrate and a conductive layer disposed on the substrate;

[0022] forming a mesoporous electron transport layer on the conductive substrate, wherein the mesoporous electron transport layer comprises a mesoporous electron transport skeleton and an interface modification layer, wherein the interface modification layer is coated on the mesoporous surface of the mesoporous electron transport skeleton, and the material of the interface modification layer is an insulating oxide material;

[0023] forming a mesoporous spacer layer on the mesoporous electron transport layer;

[0024] forming a porous counter electrode layer on the mesoporous spacer layer;

[0025] A perovskite layer is formed in the pore structures of the mesoporous electron transport layer, the mesoporous spacer layer and the porous counter electrode layer.

[0026] According to an embodiment of the present invention, the above-mentioned preparation method may further include the following technical features:

[0027] According to an embodiment of the present invention, the step of forming the mesoporous electron transport layer includes: forming a mesoporous electron transport skeleton on the conductive substrate; placing the substrate formed with the mesoporous electron transport skeleton in a precursor solution, taking it out after soaking for a predetermined time, and curing it under predetermined conditions to obtain the interface modification layer. By soaking in the solution, the mesoporous electron transport skeleton, such as mesoporous titanium oxide, can be soaked in the precursor solution, and the interface modification layer can be obtained after curing.

[0028] According to an embodiment of the present invention, a mesoporous electron transport skeleton (such as mesoporous titanium oxide) is immersed in the precursor solution at 20-90° C. and then cured at 300-450° C. to form the interface modification layer.

[0029] According to an embodiment of the present invention, the precursor solution comprises:

[0030] A precursor, wherein the precursor is selected from at least one of magnesium isopropoxide, magnesium acetate, magnesium nitrate, aluminum isopropoxide, organic silicon salt, and lanthanum nitrate;

[0031] The solvent is selected from at least one of acetylacetone, isopropanol, ethanol, methanol and butanol.

[0032] The precursor is dispersed by a suitable solvent, so as to achieve the purpose of controlling the concentration of the precursor solution; the formed precursor solution can be used to soak the mesoporous electron transport skeleton, and after soaking for a certain period of time, the interface modification layer can be obtained by curing.

[0033] According to an embodiment of the present invention, the material of the interface modification layer is selected from at least one of MgO, Al2O3, SiO2, and La2O3, and the thickness of the interface modification layer is 0.1 to 15 nm;

[0034] The mesoporous electron transport skeleton is a mesoporous TiO2 layer;

[0035] The mesoporous spacer layer is a ZrO2 layer;

[0036] The porous counter electrode layer is a porous carbon electrode layer.

[0037] The beneficial effects achieved by the present invention are:

[0038] The provided solar cell is prepared by immersing a mesoporous electron transport skeleton, such as mesoporous titanium oxide, in a precursor solution (such as a solution of an organic silicon salt), and subjecting the resulting structure to a high-temperature heat treatment, so that a thin insulating oxide layer (such as a silicon oxide layer) is coated on the mesoporous surface of the skeleton. The oxide layer does not affect the extraction of electrons by the mesoporous electron transport skeleton, and at the same time, passivates titanium dioxide defects, reduces recombination centers, reduces performance losses, and thereby reduces charge recombination and improves device efficiency. DETAILED DESCRIPTION

[0039] Embodiments of the present invention are described in detail below. The embodiments described below are exemplary and intended to be used to explain the present invention, but should not be construed as limiting the present invention.

[0040] Printable mesoscopic perovskite solar cell devices usually require high-temperature sintering to prepare. During the sintering process, the electron transport layer titanium oxide will produce a large number of oxygen vacancy defects due to the influence of the sintering environment and sintering atmosphere. These oxygen defects easily capture electrons and undergo non-radiative recombination with holes in the perovskite, resulting in performance loss of the device.

[0041] To this end, the present invention provides a solar cell, the solar cell comprising:

[0042] Conductive substrate;

[0043] A mesoporous electron transport layer, wherein the mesoporous electron transport layer is disposed on the conductive substrate;

[0044] A mesoporous spacer layer, wherein the mesoporous spacer layer is disposed on the mesoporous electron transport layer;

[0045] A porous counter electrode layer, wherein the porous counter electrode layer is disposed on the mesoporous spacer layer;

[0046] A perovskite layer, wherein the perovskite layer is disposed in the pore structure of the mesoporous electron transport layer, the mesoporous spacer layer and the porous counter electrode layer;

[0047] The mesoporous electron transport layer comprises a mesoporous electron transport skeleton and an interface modification layer, wherein the interface modification layer is coated on the mesoporous surface of the mesoporous electron transport skeleton, and the material of the interface modification layer is an insulating oxide material.

[0048] The provided solar cell can passivate the defects of the mesoporous electron transport skeleton, reduce the recombination center, reduce the performance loss, and play the effect of reducing charge recombination, thereby improving the efficiency of the device by coating the interface modification layer formed by the insulating oxide material on the mesoporous surface of the mesoporous electron transport skeleton. According to a specific embodiment, the material of the interface modification layer is selected from at least one of MgO, Al2O3, SiO2, and La2O3. These materials can be used as insulating oxide materials to form an interface modification layer, thereby reducing the effect of charge recombination and improving the efficiency of the device. According to a specific embodiment, the interface modification layer material is SiO2.

[0049] According to a specific embodiment, the thickness of the interface modification layer is 0.1-15nm. According to a preferred embodiment, the thickness of the interface modification layer is 3-13nm, especially 6-10nm. The thickness of the interface modification layer can be 2nm, 3nm, 4nm, 5nm, 6nm, 7nm, 8nm, 9nm, 10nm, 11nm, 12nm, 13nm, 14nm, 15nm. The thickness of the interface modification layer is maintained at a certain thickness, which can take into account both device efficiency and barrier effect. When the thickness of the interface modification layer is thicker, due to the effect of insulation, the interface resistance will be large, and the carriers cannot be effectively separated, thereby causing serious interface recombination and device efficiency decline, but the thickness is too low, the barrier effect is poor, and it is impossible to effectively block, and the modification effect is not obvious.

[0050] According to a specific embodiment, the mesoporous electron transport skeleton is a mesoporous TiO2 layer.

[0051] According to a specific embodiment, the mesoporous spacer layer is a mesoporous ZrO2 layer.

[0052] The porous counter electrode layer is a porous carbon electrode layer.

[0053] The present invention also provides a method for preparing the above solar cell, the method comprising the following steps:

[0054] Providing a conductive substrate, the conductive substrate comprising a substrate and a conductive layer disposed on the substrate;

[0055] forming a mesoporous electron transport layer on the conductive substrate, wherein the mesoporous electron transport layer comprises a mesoporous electron transport skeleton and an interface modification layer, wherein the interface modification layer is coated on the mesoporous surface of the mesoporous electron transport skeleton, and the material of the interface modification layer is an insulating oxide material;

[0056] forming a mesoporous spacer layer on the mesoporous electron transport layer;

[0057] forming a porous counter electrode layer on the mesoporous spacer layer;

[0058] A perovskite layer is formed in the pore structures of the mesoporous electron transport layer, the mesoporous spacer layer and the porous counter electrode layer.

[0059] According to a specific embodiment, the step of forming the mesoporous electron transport layer includes: forming a mesoporous electron transport skeleton on the conductive substrate; placing the substrate formed with the mesoporous electron transport skeleton in a precursor solution, taking it out after soaking for a predetermined time, and curing it under predetermined conditions to obtain the interface modification layer. By soaking in the solution, the mesoporous electron transport skeleton, such as mesoporous titanium oxide, can be soaked in the precursor solution, and the interface modification layer can be obtained after curing.

[0060] According to a specific embodiment, the mesoporous electron transport skeleton (such as mesoporous titanium oxide) is immersed in the precursor solution at 20-90° C., and then cured at 300-450° C. to form the interface modification layer.

[0061] According to a specific embodiment, the precursor solution comprises:

[0062] A precursor, wherein the precursor is selected from at least one of magnesium isopropoxide, magnesium acetate, magnesium nitrate, aluminum isopropoxide, organic silicon salt, and lanthanum nitrate;

[0063] The solvent is selected from at least one of acetylacetone, isopropanol, ethanol, methanol and butanol. The precursor is dispersed by the solvent to obtain a precursor solution for soaking the mesoporous electron transport skeleton. According to a specific embodiment, the solvent is acetylacetone and isopropanol. For example, the precursor and acetylacetone can be dissolved in isopropanol to obtain a corresponding precursor solution.

[0064] According to a specific embodiment, the material of the interface modification layer is selected from at least one of MgO, Al2O3, SiO2, and La2O3, and the thickness of the interface modification layer is 0.1 to 15 nm;

[0065] The mesoporous electron transport framework is mesoporous TiO2;

[0066] The mesoporous spacer layer is mesoporous ZrO2;

[0067] The porous counter electrode layer is a porous carbon electrode layer.

[0068] The present invention also provides a mesoporous electron transport layer, which includes a mesoporous electron transport skeleton and an interface modification layer, wherein the interface modification layer is coated on the mesoporous surface of the mesoporous electron transport skeleton, and the material of the interface modification layer is an insulating oxide material, and the thickness of the interface modification layer is 0.1 to 15 nm. The provided mesoporous electron transport layer is formed by depositing an insulating oxide material on the surface of the mesoporous electron transport skeleton to form an interface modification layer, and the thickness of the interface modification layer is 0.1 to 15 nm. The thin interface modification layer formed does not affect the extraction of charge by mesoporous titanium dioxide, and at the same time, passivates titanium dioxide defects, reduces recombination centers, reduces performance losses, reduces charge recombination, and improves device efficiency.

[0069] According to an embodiment of the present invention, the material of the interface modification layer is selected from at least one of MgO, Al2O3, SiO2, and La2O3. According to a preferred embodiment of the present invention, the material of the interface modification layer is SiO2.

[0070] The scheme of the present invention is described below by specific examples. It should be noted that these specific examples are only used to explain the present invention and should not be regarded as limiting the scope of protection of the present invention. The reagents or materials used in the examples are all commonly used materials in the art and can be obtained commercially.

[0071] Example 1

[0072] Example 1 A solar cell was prepared.

[0073] 1. Preparation of three-layer porous membrane:

[0074] An insulating oxide layer containing SiO2 is deposited on the surface of TiO2 by immersion method. The specific process is as follows:

[0075] The titanium precursor solution is sprayed on the FTO glass at 450°C to obtain a compact TiO2 dense layer. After cooling to room temperature, the m-TiO2 mesoporous layer is screen-printed and sintered to remove the organic components. After cooling, the mesoporous titanium dioxide is immersed in the organosilicon precursor solution at 40°C for 2min, 5min, and 10min respectively. After the immersion is completed, it is treated at 400°C to obtain SiO2 films with film thicknesses of 3nm, 8nm, and 13nm, respectively. The ZrO2 mesoporous layer and carbon layer are then screen-printed on the device.

[0076] Among them, the screen printing of the ZrO2 mesoporous layer and the carbon layer on the device can refer to the commonly used methods in the art.

[0077] 2. Perovskite filling

[0078] (1) Preparation of perovskite solution;

[0079] Lead iodide and potassium iodide powders were weighed according to the stoichiometric ratio, and the powders were dissolved in DMF, DMSO and NMF solutions at a certain concentration of 1.6 mol / L, and stirred on a hot plate at 50-70° C. for 1-2 h to obtain a perovskite solution.

[0080] (2) Filling of perovskite solution and crystal growth:

[0081] First, cover the non-filled area with tape, then transfer the prepared perovskite solution and use a one-step drop coating method to fill 3 to 5 μL into each small battery. After the solution diffuses over the scribed position, let it stand for a certain period of time and then anneal it on a hot plate at 58 to 65°C.

[0082] The performance of the prepared electronic device was characterized, and the results are shown in Table 1.

[0083] As shown in Table 1, a sample with a SiO2 layer thickness of 3 nm was prepared by immersing for 2 min, which was recorded as sample 1;

[0084] The sample with a SiO2 layer thickness of 8 nm was prepared by soaking for 5 min, and was recorded as sample 2;

[0085] A sample with a SiO2 layer thickness of 13 nm was prepared by soaking for 10 minutes and was recorded as Sample 3.

[0086] The control sample was not coated with silicon oxide.

[0087] Table 1 Performance of electronic devices

[0088]

[0089]

[0090] It is not difficult to see from the results given in Table 1 above that the successful coating of SiO2 does not affect the extraction of charge by mesoporous titanium dioxide. At the same time, it can effectively passivate titanium dioxide defects, reduce recombination centers, reduce performance losses, and reduce charge recombination, thereby improving the photoelectric conversion efficiency of the device. It is not difficult to see from the results given in Table 1 that compared with the control sample, the photoelectric conversion efficiency of samples 1 to 3 has been improved, especially when the thickness of the silicon oxide layer is 8nm, the efficiency of photoelectric conversion is improved even more.

[0091] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0092] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A solar cell, characterized in that: The solar cell comprises: Conductive substrate; A mesoporous electron transport layer, wherein the mesoporous electron transport layer is disposed on the conductive substrate; A mesoporous spacer layer, wherein the mesoporous spacer layer is disposed on the mesoporous electron transport layer; A porous counter electrode layer, wherein the porous counter electrode layer is disposed on the mesoporous spacer layer; A perovskite layer, wherein the perovskite layer is disposed in the pore structure of the mesoporous electron transport layer, the mesoporous spacer layer and the porous counter electrode layer; The mesoporous electron transport layer comprises a mesoporous electron transport skeleton and an interface modification layer, wherein the interface modification layer is coated on the mesoporous surface of the mesoporous electron transport skeleton, and the material of the interface modification layer is an insulating oxide material.

2. The solar cell according to claim 1, characterized in that The material of the interface modification layer is selected from at least one of MgO, Al2O3, SiO2, and La2O3.

3. The solar cell according to claim 1, characterized in that The thickness of the interface modification layer is 0.1-15 nm.

4. The solar cell according to claim 1, characterized in that The mesoporous electron transport skeleton is a mesoporous TiO2 layer.

5. The solar cell according to claim 1, characterized in that: The mesoporous spacer layer is a ZrO2 or Al2O3 layer; The porous counter electrode layer is a porous carbon electrode layer.

6. A method for preparing a solar cell, characterized in that: The preparation method comprises the following steps: Providing a conductive substrate, the conductive substrate comprising a substrate and a conductive layer disposed on the substrate; forming a mesoporous electron transport layer on the conductive substrate, wherein the mesoporous electron transport layer comprises a mesoporous electron transport skeleton and an interface modification layer, wherein the interface modification layer is coated on the mesoporous surface of the mesoporous electron transport skeleton, and the material of the interface modification layer is an insulating oxide material; forming a mesoporous spacer layer on the mesoporous electron transport layer; forming a porous counter electrode layer on the mesoporous spacer layer; A perovskite layer is formed in the pore structures of the mesoporous electron transport layer, the mesoporous spacer layer and the porous counter electrode layer.

7. The preparation method according to claim 6, characterized in that: The steps of forming the mesoporous electron transport layer include: forming a mesoporous electron transport skeleton on the conductive substrate; The substrate formed with the mesoporous electron transport skeleton is placed in a precursor solution, taken out after being immersed for a predetermined time, and cured under predetermined conditions to obtain the interface modification layer.

8. The preparation method according to claim 7, characterized in that: The mesoporous electron transport skeleton is immersed in the precursor solution at 20-90° C., and then cured at 300-450° C. to form the interface modification layer.

9. The preparation method according to claim 7 or 8, characterized in that: The precursor solution comprises: A precursor, wherein the precursor is selected from at least one of magnesium isopropoxide, magnesium acetate, magnesium nitrate, aluminum isopropoxide, organic silicon salt, and lanthanum nitrate; The solvent is selected from at least one of acetylacetone, isopropanol, ethanol, methanol and butanol.

10. The preparation method according to claim 6, characterized in that: The material of the interface modification layer is selected from at least one of MgO, Al2O3, SiO2, and La2O3, and the thickness of the interface modification layer is 0.1 to 15 nm; The mesoporous electron transport skeleton is a mesoporous TiO2 layer; The mesoporous spacer layer is a ZrO2 layer; The porous counter electrode layer is a porous carbon electrode layer.

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