Perovskite solar cell, preparation method thereof and photovoltaic module

Abstract

The invention relates to a perovskite solar cell, a preparation method thereof and a photovoltaic module. The perovskite solar cell comprises a hole transport layer, the hole transport layer comprises a metal oxide layer, and the grain size of the metal oxide layer is 5-10 nm; the self-assembly molecular layer is arranged on the first surface of the metal oxide layer, and the hydroxyl coverage rate of the first surface is 7%-25%. According to the perovskite solar cell, the defects of the hole transport layer and the defects of the self-assembly molecular layer can be improved at the same time, and the film layer binding force between the hole transport layer and the self-assembly molecular layer is enhanced, so that the carrier transport efficiency in the perovskite solar cell is effectively improved, and the photoelectric property is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of solar cells, in particular to a perovskite solar cell, a preparation method thereof and a photovoltaic module. BACKGROUND

[0002] In the perovskite solar cell, the hole transport layer and the self-assembled molecular layer are often arranged in combination. However, the hole transport layer and the self-assembled molecular layer each have some defect problems, which causes the carrier transport to be blocked, and affects the photoelectric performance of the perovskite solar cell. SUMMARY

[0003] The present application discloses a perovskite solar cell, a preparation method thereof and a photovoltaic module, so as to solve the problem that the defects in the hole transport layer and the self-assembled molecular layer cause the carrier transport to be blocked.

[0004] In order to achieve the above-mentioned purpose, in a first aspect, the present application discloses a perovskite solar cell, comprising: a hole transport layer, the hole transport layer comprising a metal oxide layer, the metal oxide layer having a grain size of 5 nm to 10 nm; a self-assembled molecular layer, the self-assembled molecular layer being arranged on a first surface of the metal oxide layer, the first surface having a hydroxyl coverage of 7% to 25%.

[0005] Further, the first surface has a roughness of 4 nm to 8 nm; and / or, the metal oxide layer has a carrier concentration of 2.14×10 19 / cm 3 to 4.50×10 19 / cm 3 ; and / or, the metal oxide layer has a carrier mobility of 0.366 cm 2 / v.s to 0.731 cm 2 / v.s.

[0006] Further, the material of the metal oxide layer comprises at least one of nickel oxide, cobalt oxide, copper oxide, cuprous oxide or tungsten oxide; the perovskite solar cell further comprises a perovskite layer, the perovskite layer being arranged on a surface of the self-assembled molecular layer away from the hole transport layer, the perovskite layer having a structural formula of ABX3, wherein the A is an A-site cation, the B is a B-site cation, and the X is an X-site anion, the A-site cation comprising FA + , MA + , Cs + , K + , Ca 2+ , Zn 2+Na + 、Rb + DMA + BA + PA + AA + BMIM + EA + or EDA 2+ At least one of the following, wherein the B-site cation includes Pb 2+ Ga 2+ and Sn 2+ At least one of the following, wherein the X-position anion includes I - F - ,Br - Cl - SCN - OCN - BF4 - TFSI - CF3 - CF3CO2 - COO - or SO3 - At least one of them; and / or, The material of the self-assembled molecular layer includes one or more of 4PACz, 4PADCB, MeO-2PACz, 2PACz or Me-4PACz.

[0007] Furthermore, the material of the metal oxide layer is nickel oxide, and the nickel oxide includes Ni. 2+ and Ni 3 + ; The perovskite layer includes the FA. + The MA + The I - The F - The Br - The Cl - The Pb 2+ At least one of them.

[0008] Furthermore, the perovskite solar cell also includes a hole-electron recombination layer, which and the self-assembled molecular layer are located on opposite sides of the hole transport layer.

[0009] Furthermore, the perovskite solar cell is a perovskite tandem solar cell, comprising: a base cell, and a hole-electron recombination layer, a hole transport layer, a self-assembled molecular layer, a perovskite layer, an electron transport layer, and a first electrode sequentially stacked on the surface of the base cell; a second electrode, disposed on the base cell, wherein one of the first electrode and the second electrode is a positive electrode and the other is a negative electrode; or, The perovskite solar cell is a perovskite single-junction cell, which includes: a substrate, and a transparent conductive substrate, a hole transport layer, a self-assembled molecular layer, a perovskite layer, an electron transport layer, a transparent conductive layer, and a first electrode sequentially stacked on the surface of the substrate; and a second electrode, wherein the second electrode and the hole transport layer are disposed on different regions of the same side surface of the transparent conductive substrate, and one of the first electrode and the other of the second electrode is a positive electrode and the other is a negative electrode.

[0010] Furthermore, the bottom battery includes any one of a heterojunction battery, a passivated contact battery, a copper indium gallium selenide battery, and an organic battery; and / or, The thickness of the hole transport layer is 10 nm to 25 nm.

[0011] Secondly, this application provides a method for preparing a perovskite solar cell, wherein the perovskite solar cell is the perovskite solar cell described in the first aspect, and the preparation method includes the following steps: Preparation of a metal oxide layer for hole transport: Ammonia is coated onto a metal oxide precursor and annealed to obtain the metal oxide layer. The grain size of the metal oxide layer is 5 nm to 10 nm. The metal oxide layer has a first surface with a hydroxyl coverage of 7% to 25%. The metal oxide layer and the metal oxide precursor are made of the same material but have different hydroxyl coverage.

[0012] Furthermore, in the annealing step: the annealing temperature is 50℃~200℃, and the annealing time is 3 min~20 min.

[0013] Furthermore, in the step of coating the metal oxide precursor with ammonia, the pH of the ammonia is 8-12, and the addition volume is 8 μL / cm. 2 ~32 μL / cm 2 The roughness of the first surface is 4 nm to 8 nm.

[0014] Furthermore, in the step of coating the metal oxide precursor with ammonia, the amount of ammonia added is 8 μL / cm. 2 ~32 μL / cm 2The spin coating speed is 500 r / s-4000 r / s, and the spin coating time is 5 s-30 s.

[0015] Furthermore, prior to the step of coating the metal oxide precursor with ammonia, the step of preparing the hole transport layer further includes preparing the metal oxide precursor: an RF sputtering target, wherein the process conditions of the RF sputtering target are: sputtering pressure of 0.3 Pa to 1.0 Pa, sputtering temperature of 23°C to 100°C, and sputtering power of 100 W to 1100 W, and the target includes at least one of nickel oxide, cobalt oxide, copper oxide, cuprous oxide, or tungsten oxide.

[0016] Thirdly, embodiments of this application provide a photovoltaic module, the photovoltaic module comprising the perovskite solar cell as described in the first aspect, or the photovoltaic module comprising the perovskite solar cell prepared by the preparation method of the second aspect.

[0017] Compared with the prior art, the beneficial effects of this application are as follows: In the perovskite solar cell of this application, the grain size of the metal oxide layer is controlled to be 5 nm to 10 nm, and the hydroxyl coverage of the interface between the metal oxide layer and the self-assembled molecular layer is controlled to be 7% to 25%. This allows the perovskite solar cell of this application to simultaneously improve the defects of the hole transport layer, the defects of the self-assembled molecular layer, and the film bonding force between the hole transport layer and the self-assembled molecular layer, thereby effectively improving the carrier transport efficiency in the perovskite solar cell and enhancing the photoelectric performance.

[0018] The perovskite solar cell of this application features a metal oxide layer with a grain size of 5 nm to 10 nm and a surface hydroxyl coverage of 7% to 25%. This allows for the mitigation of defects caused by excessively small or large grain sizes in the metal oxide layer. By controlling the hydroxyl coverage, the number of anchoring points in the self-assembled molecular layer and the metal oxide layer is increased, ensuring carrier transport performance without increasing carrier transport paths. This strengthens the interaction between the two layers, improving the stability and uniformity of the self-assembled molecular layer, reducing defects in the self-assembled molecular layer, and improving the contact performance between the two layers. Therefore, in the perovskite solar cell of this application, the carrier transport efficiency is improved within the hole transport layer, within the self-assembled molecular layer, and at the interface between the hole transport layer and adjacent self-assembled molecular layers, resulting in enhanced photoelectric performance of the perovskite solar cell. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the 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.

[0020] Figure 1 This is a schematic diagram of a metal oxide layer and a self-assembled molecular layer provided in an embodiment of this application; Figure 2 This is a schematic diagram of the structure of the first perovskite solar cell provided in the embodiments of this application; Figure 3 This is a schematic diagram of the structure of the second type of perovskite solar cell provided in the embodiments of this application; Figure 4 This is a schematic diagram of the structure of the third type of perovskite solar cell provided in the embodiments of this application.

[0021] Explanation of reference numerals in the attached figures: 1. Hole transport layer; 10. Metal oxide precursor; 11. Metal oxide layer; 111. Main layer; 112. Surface layer; 2. Self-assembled molecular layer; 3. Perovskite layer; 31. Passivation layer; 4. Hole-electron recombination layer; 5. Bottom cell; 6. Electron transport layer; 61. Buffer layer; 71. First electrode; 72. Second electrode; 8. Transparent conductive layer; 81. Antireflection layer; 9. Substrate; 91. Transparent conductive substrate. Detailed Implementation

[0022] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0023] In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0024] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0025] Furthermore, the terms "installation," "setup," "equipped with," "connection," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0026] Furthermore, the terms "first," "second," etc., are primarily used to distinguish different devices, components, or parts (which may be the same or different in specific type and construction), and are not intended to indicate or imply the relative importance or quantity of the indicated devices, components, or parts. Unless otherwise stated, "a plurality of" means two or more.

[0027] In perovskite solar cells, hole transport layers and self-assembled molecular layers are often paired together for synergistic effects. The two layers are primarily connected through coordination bonds formed by the anchoring of self-assembled molecules in the self-assembled molecular layer to hydroxyl groups on the surface of the hole transport layer, thus creating a self-assembled molecular layer on the hole transport layer surface. However, both the hole transport layer and the self-assembled molecular layer contain defects that can hinder carrier transport and affect the photoelectric performance of the perovskite solar cell.

[0028] Defects in the hole transport layer include surface and internal defects, which are related to the grain size in the film. When the grain size is too small, unsaturated coordinated metal ions (e.g., Ni²⁺) on the surface of the hole transport layer... + / Ni³ + Increased dangling bonds, oxygen vacancies, and hydroxyl agglomeration create more carrier trapping centers. Furthermore, increased grain boundary density in the hole transport layer intensifies carrier scattering and hinders transport. When grain size is too large, on the one hand, intensified grain boundary dislocations and lattice distortions in the hole transport layer exacerbate carrier recombination; on the other hand, the uneven surface of large-grain films results in discontinuous surface potential distribution, further intensifying carrier recombination.

[0029] The defects in the self-assembled molecular layer mainly stem from the uneven distribution of self-assembled molecules within the film. These defects cause carrier transport mismatch and exacerbate carrier recombination. The uniformity of the self-assembled molecular layer distribution depends on the coverage of hydroxyl groups on the hole transport layer surface: when the hydroxyl coverage is too low, the coverage of the self-assembled molecular layer on the hole transport layer becomes discontinuous, and the empty regions become carrier recombination centers, reducing carrier transport efficiency; when the hydroxyl coverage is too high, the spacing between adjacent self-assembled molecules is too small, creating steric hindrance, increasing the carrier transport path, and reducing transport efficiency. In addition, the possibility of side reactions between hydroxyl groups and self-assembled molecules increases, further reducing the carrier transport performance of the self-assembled molecules.

[0030] Based on an in-depth analysis of the causes of the above-mentioned technical problems, this application provides a perovskite solar cell and its preparation method, as well as a photovoltaic module. By optimizing the grain size of the hole transport layer and the hydroxyl coverage of the surface, the above-mentioned technical problems are solved, reducing film defects while improving the uniformity of self-assembled molecular layer distribution, improving carrier transport efficiency, and ultimately improving the photoelectric performance of perovskite solar cells.

[0031] The technical solutions provided in this application will be further described below with reference to the embodiments and accompanying drawings.

[0032] like Figures 1-4 As shown, this application provides a perovskite solar cell, which includes: Hole transport layer 1, the hole transport layer 1 includes a metal oxide layer 11, the grain size of the metal oxide layer 11 is 5nm~10nm; Self-assembled molecular layer 2 is disposed on the first surface of metal oxide layer 11, and the hydroxyl coverage of the first surface is 7%~25%.

[0033] The hole transport layer 1 may be only the metal oxide layer 11, or it may include other film layers with hole transport properties on the side of the metal oxide layer 11 facing away from the self-assembled molecular layer 2. This application does not limit other film layers.

[0034] In this process, the self-assembled molecules in the self-assembled molecular layer 2 are combined with the hydroxyl groups on the first surface of the metal oxide layer 11 through an anchoring effect. After the anchoring effect, the self-assembled molecules form coordination bonds with the metal ions in the metal oxide layer 11.

[0035] The grain size was measured using an X-ray diffractometer, and the hydroxyl coverage was measured using an X-ray photoelectron spectroscopy (XPS). Taking nickel oxide as the material of the metal oxide layer as an example, the XPS measured the number of nickel atoms and the number of hydroxyl oxygen atoms. Since hydroxyl atoms are bonded to nickel atoms, the ratio of the number of hydroxyl oxygen atoms to the number of nickel atoms is the hydroxyl coverage on the first surface of the nickel oxide layer.

[0036] Exemplarily, the grain size of the metal oxide layer 11 is 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, or 10 nm. Preferably, the grain size of the metal oxide layer 11 is 8 nm. Exemplarily, the hydroxyl group coverage of the first surface is 7%, 10%, 13%, 16%, 20%, 22%, 24%, or 25%. Preferably, the hydroxyl group coverage of the first surface is 19%.

[0037] In this embodiment, the grain size of the metal oxide layer 11 is controlled to be 5 nm to 10 nm, and the hydroxyl coverage of the interface between the metal oxide layer 11 and the self-assembled molecular layer 2 is controlled to be 7% to 25%. This allows the perovskite solar cell of this application to simultaneously improve the defects of the hole transport layer 1, the defects of the self-assembled molecular layer 2, and the film bonding force between the hole transport layer 1 and the self-assembled molecular layer 2, thereby effectively improving the carrier transport efficiency in the perovskite solar cell and enhancing its photoelectric performance.

[0038] In this application, the metal oxide layer 11 of the perovskite solar cell simultaneously possesses a grain size of 5 nm to 10 nm and a surface hydroxyl coverage of 7% to 25%. This allows for the mitigation of defects caused by excessively small or large grain sizes in the metal oxide layer 11. Furthermore, by controlling the hydroxyl coverage, the number of anchoring points between the self-assembled molecular layer 2 and the metal oxide layer 11 is increased without altering carrier transport performance or increasing the number of transport paths. This strengthens the interaction between the two layers, improving the stability and uniformity of the self-assembled molecular layer 2, reducing defects in the self-assembled molecular layer 2, and improving the contact performance between the two layers. Therefore, in this application's perovskite solar cell, the carrier transport efficiency is improved within the hole transport layer 1, within the self-assembled molecular layer 2, and at the adjacent interfaces between the hole transport layer 1 and the self-assembled molecular layer 2, thereby enhancing the photoelectric performance of the perovskite solar cell.

[0039] Furthermore, the roughness of the first surface is 4 nm to 8 nm.

[0040] The roughness is obtained by atomic force microscopy. For example, the roughness of the first surface is 4 nm, 5 nm, 6 nm, 7 nm, or 8 nm. Preferably, the roughness of the first surface is 5 nm. In this embodiment, when the roughness of the first surface is within the above range, it can improve the uniformity of the self-assembled molecular layer 2 covering the hole transport layer 1, while ensuring the bonding force between the two film layers, thereby improving the uniformity and stability of the self-assembled molecular layer 2.

[0041] Furthermore, the carrier concentration of the metal oxide layer 11 is 2.14 × 10⁻⁶. 19 / cm 3 ~4.50×10 19 / cm 3 The carrier mobility of the metal oxide layer 11 is 0.366 cm⁻¹. 2 / vs~0.731 cm 2 / vs.

[0042] The carrier concentration and carrier mobility were obtained using a Hall effect tester. For example, the carrier concentration of the metal oxide layer 11 was 2.14 × 10⁻⁶. 19 / cm 3 2.49×10 19 / cm 3 2.79×10 19 / cm 3 3.39×10 19 / cm 3 3.62×10 19 / cm 3 3.87×10 19 / cm 3 4.36×10 19 / cm 3 Or 4.50×10 19 / cm 3 In this embodiment, under this carrier concentration condition, the carrier mobility increases, indicating that the carrier transport performance is improved. Preferably, the carrier concentration of the metal oxide layer 11 is 2.19 × 10⁻⁶. 19 / cm 3 For example, the carrier mobility of the metal oxide layer 11 is 0.366 cm⁻¹. 2 / vs、0.463 cm 2 / vs、0.562 cm 2 / vs、0.674 cm 2 / vs or 0.731 cm 2 / vs. Preferably, the carrier mobility of the metal oxide layer 11 is 0.562 cm⁻¹.2 / vs.

[0043] Optionally, the material of the self-assembled molecular layer 2 includes one or more of 4PACz, 4PADCB, MeO-2PACz, 2PACz, or Me-4PACz. Among them, 4PACz, MeO-2PACz, 4PACz, or MeO-2PACz are all derivatives of carbazole phosphonic acid (PACz).

[0044] Optionally, the material of the metal oxide layer 11 includes at least one of nickel oxide, cobalt oxide, copper oxide, cuprous oxide, or tungsten oxide.

[0045] Optionally, the perovskite solar cell further includes a perovskite layer 3, which is disposed on the surface of the self-assembled molecular layer 2 away from the hole transport layer 1. The structural formula of the perovskite layer 3 is: ABX3, where A is an A-site cation, B is a B-site cation, and X is an X-site anion. The A-site cation includes FA. + MA + Cs + K + Ca 2+ Zn 2+ Na + 、Rb + DMA + BA + PA + AA + BMIM + EA + or EDA 2+ At least one of them, the B-site cation includes Pb 2+ Ga 2+ and Sn 2+ At least one of them, the X-position anion includes I - F - ,Br - Cl - SCN - OCN - BF4 - TFSI - CF3 - CF3CO2 - COO - or SO3 - At least one of them. In the embodiments of this application, the self-assembled molecular layer 2 with improved stability and uniformity is located between the metal oxide layer 11 and the perovskite layer 3, avoiding direct contact between the metal oxide layer 11 and the perovskite layer 3, and improving the problem of energy level mismatch between the metal oxide layer 11 and the perovskite.

[0046] Furthermore, the metal oxide layer 11 is made of nickel oxide, which includes Ni. 2+ and Ni 3+ The perovskite layer 3 includes FA + MA + I - F - ,Br - Cl - At least one of them.

[0047] Among them, FA + It is a formamidinium cation, MA + It is a methylamine cation, FA + with Ni 3+ The reaction produces small molecules such as CO2 and NH3, MA + with Ni 3+ The reaction generates small molecules such as HCN and urea, causing the ABX3 octahedral structure in perovskite layer 3 to collapse. Among them, I... - F - ,Br - Cl - with Ni 3+ A redox reaction occurs, generating the corresponding elemental substance, causing the ABX3 octahedral structure in perovskite layer 3 to collapse.

[0048] In this embodiment, the self-assembled molecular layer 2, which improves stability and uniformity, is located between the metal oxide layer 11 and the perovskite layer 3. This reduces the contact between the perovskite layer 3 and the metal oxide layer 11, and the perovskite layer 3 is less susceptible to oxidation by Ni. 3+ The possibility of decomposition increases the stability of perovskite solar cells.

[0049] Furthermore, the perovskite solar cell also includes a hole-electron recombination layer 4, which and the self-assembled molecular layer 2 are located on opposite sides of the hole transport layer 1. The hole-electron recombination layer 4 is made of at least one of indium tin oxide, indium zinc oxide, or indium tungsten oxide. In this embodiment, the hole transport layer 1, with a grain size of 5 nm to 10 nm, has few defects. These defects include those located at the interface between the hole-electron recombination layer 4 and the hole transport layer 1. Reducing these defects at the interface decreases carrier recombination at the interface between the hole-electron recombination layer 4 and the hole transport layer 1, thereby improving carrier transport efficiency.

[0050] Optionally, such as Figure 2As shown, the perovskite solar cell is a perovskite tandem solar cell, which includes: a base cell 5, and a hole-electron recombination layer 4, a hole transport layer 1, a self-assembled molecular layer 2, a perovskite layer 3, an electron transport layer 6, and a first electrode 71 sequentially stacked on the surface of the base cell 5; a second electrode 72, which is disposed on the base cell 5, with the first electrode 71 being a positive electrode and the second electrode 72 being a negative electrode.

[0051] Among them, the bottom battery 5 includes any one of heterojunction battery, passivated contact battery, copper indium gallium selenide battery, and organic battery.

[0052] The electron transport layer 6 is made of either C60 or tin oxide.

[0053] The hole transport layer 1 has a thickness of 10 nm to 25 nm, the electron transport layer 6 has a thickness of 10 nm to 25 nm, and the perovskite layer 3 has a thickness of 450 nm to 500 nm.

[0054] Exemplarily, the thickness of hole transport layer 1 is 10 nm, 14 nm, 18 nm, 21 nm, 23 nm, or 25 nm. Preferably, the thickness of hole transport layer 1 is 18 nm. Exemplarily, the thickness of electron transport layer 6 is 10 nm, 14 nm, 18 nm, 21 nm, 23 nm, or 25 nm. Preferably, the thickness of electron transport layer 6 is 15 nm. Exemplarily, the thickness of perovskite layer 3 is 450 nm, 460 nm, 470 nm, 480 nm, 490 nm, or 500 nm. Preferably, the thickness of perovskite layer 3 is 460 nm.

[0055] The first electrode 71 and the second electrode 72 are made of silver, and their thicknesses range from 100 nm to 550 nm. For example, the thicknesses of the first electrode 71 and the second electrode 72 are 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, 350 nm, 400 nm, 450 nm, 500 nm, or 550 nm, respectively. Preferably, the thickness of the first electrode 71 and the second electrode 72 is 350 nm.

[0056] Furthermore, such as Figure 3 As shown, in addition to the structure described above, perovskite solar cells may also include other functional films, including: A passivation layer 51 is disposed between the perovskite layer 3 and the electron transport layer 6. The material of the passivation layer 51 includes LiF or a two-dimensional perovskite material, and the thickness of the passivation layer 51 is 0.5 nm to 5 nm. Exemplarily, the thickness of the passivation layer 51 is 0.5 nm, 1 nm, 2 nm, 3 nm, 4 nm, or 5 nm. Preferably, the thickness of the passivation layer 51 is 1 nm.

[0057] A buffer layer 61 is disposed on the surface of the electron transport layer 6 away from the bottom cell 5. The material of the buffer layer 61 is LiF or a two-dimensional perovskite material, and the thickness of the buffer layer 61 is 5 nm to 30 nm. Exemplarily, the thickness of the buffer layer 61 is 5 nm, 8 nm, 14 nm, 19 nm, 23 nm, 26 nm, or 30 nm. Preferably, the thickness of the buffer layer 61 is 20 nm.

[0058] A transparent conductive layer 8 is disposed on the surface of the buffer layer 61 facing away from the bottom battery 5. The material of the transparent conductive layer 8 is one or a combination of indium tin oxide, indium zinc oxide, and indium tungsten oxide. The thickness of the transparent conductive layer 8 is 30 nm to 150 nm. Exemplarily, the thickness of the transparent conductive layer 8 is 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, 130 nm, 140 nm, or 150 nm. Preferably, the thickness of the transparent conductive layer 8 is 100 nm.

[0059] An antireflection layer 81 is disposed on the surface of the transparent conductive layer 8 facing away from the bottom cell 5. The material of the antireflection layer 81 is LiF or MgF2, and the thickness of the antireflection layer 81 is 80 nm to 150 nm. Exemplarily, the thickness of the antireflection layer 81 is 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, 130 nm, 140 nm, or 150 nm. Preferably, the thickness of the antireflection layer 81 is 100 nm.

[0060] In this embodiment, the passivation layer 51, the buffer layer 61, and the antireflection layer 81 further improve the photoelectric conversion efficiency of the perovskite solar cell.

[0061] Optionally, such as Figure 4As shown, the perovskite solar cell is a perovskite single-junction cell, comprising: a substrate 9, and a transparent conductive substrate 91, a hole transport layer 1, a self-assembled molecular layer 2, a perovskite layer 3, an electron transport layer 6, a transparent conductive layer 8, and a first electrode 71 sequentially stacked on the surface of the substrate 9; and a second electrode 72. The second electrode 72 and the hole transport layer 1 are disposed on different regions of the same side surface of the transparent conductive substrate 91, with the first electrode 71 being a positive electrode and the second electrode 72 being a negative electrode. The thickness of the hole transport layer 1 is 10 nm to 25 nm. Exemplarily, the thickness of the hole transport layer 1 is 10 nm, 14 nm, 18 nm, 21 nm, 23 nm, or 25 nm. Preferably, the thickness of the hole transport layer 1 is 18 nm.

[0062] Secondly, this application also provides a method for preparing the above-mentioned perovskite solar cell. It is understood that this preparation method is one way to obtain the embodiments of this application, but is not limited to the only method. That is, the perovskite solar cell of the embodiments of this application can also be prepared by other methods, and this application does not impose any limitations on this. Therefore, it should not be construed as a limitation on the perovskite solar cell provided in the embodiments of this application.

[0063] The preparation method includes the following steps: Preparation of the metal oxide layer 11 of hole transport layer 1: Ammonia water is coated on the metal oxide precursor 10 and annealed to obtain the metal oxide layer 11. The grain size of the metal oxide layer 11 is 5 nm to 10 nm. The metal oxide layer 11 has a first surface with a hydroxyl coverage of 7% to 25%. The metal oxide layer 11 and the metal oxide precursor 10 are films of the same material but with different hydroxyl coverage and different grain sizes.

[0064] The phrase "the metal oxide layer 11 and the metal oxide precursor 10 are made of the same material but have different hydroxyl coverage and grain size" means that the metal oxide layer 11 is obtained by coating the metal oxide precursor 10 with ammonia and then annealing it. This process changes the hydroxyl coverage and grain size of the metal oxide precursor 10. The material of the metal oxide layer 11 is the same as that of the metal oxide precursor 10. Taking a nickel oxide layer as an example, both the metal oxide precursor 10 and the metal oxide layer 11 are made of nickel oxide; the only difference is that the nickel oxide used as the metal oxide precursor 10 and the nickel oxide used as the metal oxide layer 11 have different hydroxyl coverage and grain size.

[0065] In this process, after coating the metal oxide precursor 10 with ammonia, the hydroxyl groups in the ammonia can be directly adsorbed onto the surface of the metal oxide precursor 10 and coordinate with the metal ions on the surface. The ammonia can also react with the metal oxide to form corresponding metal hydroxides, thereby increasing the number of hydroxyl groups. At the same time, the ammonia can etch the metal oxide, giving its surface sites that can react with H2O and hydroxyl groups to generate new hydroxyl groups.

[0066] In this process, ammonia dissolves metal ions on the surface of the metal oxide precursor 10, forming a metal complex. Annealing causes the dissolved metal ions to diffuse inward. Due to the high metal concentration inside the film, the metal complex decomposes and reforms into metal oxide crystals, increasing the grain size of the metal oxide. Taking nickel oxide as an example, the reaction equation for this process is: .

[0067] In this embodiment, the grain size of the metal oxide layer 11 in the perovskite solar cell is controlled to be 5 nm to 10 nm, and the hydroxyl coverage of the interface between the metal oxide layer 11 and the self-assembled molecular layer 2 is controlled to be 7% to 25%. This allows the perovskite solar cell of this application to simultaneously improve the defects of the hole transport layer 1, the defects of the self-assembled molecular layer 2, and the film bonding force between the hole transport layer 1 and the self-assembled molecular layer 2, thereby effectively improving the carrier transport efficiency in the perovskite solar cell and enhancing its photoelectric performance.

[0068] Further, in the annealing step: the annealing temperature is 50℃~200℃, and the annealing time is 3 min~20 min. Exemplarily, the annealing temperature is 50℃, 70℃, 100℃, 120℃, 150℃, 180℃, or 200℃. Preferably, the annealing temperature is 150℃. Exemplarily, the annealing time is 3 min, 7 min, 11 min, 13 min, 15 min, 18 min, or 20 min. Preferably, the annealing time is 15 min. In the embodiments of this application, when the annealing temperature and annealing time are within the above ranges, a metal oxide layer 11 with a grain size of 5 nm~10 nm and a surface hydroxyl coverage of 7%~25% can be obtained more efficiently.

[0069] Furthermore, in the step of coating the metal oxide precursor 10 with ammonia, the pH of the ammonia is 8-12, and the addition volume is 8 μL / cm. 2 ~32 μL / cm 2 The roughness of the first surface is 4 nm to 8 nm. Exemplarily, the pH of the ammonia solution is 8, 9, 10, 11, or 12. Preferably, the pH of the ammonia solution is 11. Exemplarily, the amount of ammonia solution added is 8 μL / cm³. 2 11 μL / cm2 14 μL / cm 2 17μL / cm 2 22 μL / cm 2 26 μL / cm 2 29 μL / cm 2 Or 32 μL / cm 2 Preferably, the ammonia solution is added at a rate of 20 μL / cm³. 2 For example, the roughness of the first surface is 4 nm, 5 nm, 6 nm, 7 nm, or 8 nm. Preferably, the roughness of the first surface is 5 nm.

[0070] In this embodiment, when the pH and amount of ammonia added are within the aforementioned range, a first surface with a roughness of 4 nm to 8 nm is obtained. When the roughness of the first surface is within this range, the uniformity of the self-assembled molecular layer 2 covering the hole transport layer 1 can be improved, while ensuring the bonding force between the two film layers, thereby improving the uniformity and stability of the self-assembled molecular layer 2. Furthermore, when the pH of ammonia is within the aforementioned range, it can induce the recombination of hydroxyl groups on the first surface of the metal oxide layer 11 to form a hydrogen bond network, making the distribution of hydroxyl groups on the first surface of the metal oxide layer 11 more uniform. This further improves the uniformity of the self-assembled molecular layer 2 formed by the anchoring effect with hydroxyl groups, thereby reducing carrier recombination and increasing the carrier transport rate.

[0071] Further, in the step of coating the metal oxide precursor 10 with ammonia, the spin coating speed is 500 r / s-4000 r / s, and the spin coating time is 5 s-30 s. Exemplarily, the spin coating speed is 500 r / s, 800 r / s, 1300 r / s, 1900 r / s, 2200 r / s, 2700 r / s, 3400 r / s, 3800 r / s, or 4000 r / s. Preferably, the spin coating speed is 3000 r / s. Exemplarily, the spin coating time is 5 s, 7 s, 12 s, 17 s, 23 s, 28 s, or 30 s. Preferably, the spin coating time is 20 s.

[0072] In the embodiments of this application, when the spin coating speed and time are within the above range, a metal oxide layer 11 with a grain size of 5 nm to 10 nm, a surface hydroxyl coverage of 7% to 25%, and a roughness of 4 nm to 8 nm can be obtained more efficiently.

[0073] Furthermore, prior to the step of coating the metal oxide precursor 10 with ammonia, the step of preparing the hole transport layer 1 further includes preparing the metal oxide precursor 10: an RF sputtering target, wherein the process conditions of the RF sputtering target are: sputtering pressure of 0.3 Pa to 1.0 Pa, sputtering temperature of 23°C to 100°C, sputtering power of 100 W to 1100 W, and the target includes at least one of nickel oxide, cobalt oxide, copper oxide, cuprous oxide, or tungsten oxide.

[0074] Exemplary sputtering pressures are 0.3 Pa, 0.5 Pa, 0.7 Pa, 0.9 Pa, or 1.0 Pa. Preferably, the sputtering pressure is 0.5 Pa. Exemplary sputtering temperatures are 23°C, 36°C, 46°C, 54°C, 61°C, 76°C, 83°C, 95°C, or 100°C. Preferably, the sputtering temperature is 70°C. Exemplary sputtering power is 100 W, 300 W, 500 W, 700 W, 900 W, or 1100 W. Preferably, the sputtering power is 700 W.

[0075] This application also provides a photovoltaic module. The photovoltaic module includes the aforementioned solar cell, and also includes a method for preparing the aforementioned solar cell.

[0076] The technical solution of this application will be further explained below with reference to more specific embodiments and experimental test results.

[0077] Example 1 This embodiment provides a perovskite tandem solar cell, the fabrication method of which includes the following steps: Preparation of hole-electron recombination layer: Hole-electron recombination layer was prepared on HJT bottom cell by magnetron sputtering. The material of hole-electron recombination layer is indium tin oxide and the thickness is 20 nm. Preparation of metal oxide precursor: Nickel oxide precursor with a thickness of 20 nm was obtained by radio frequency sputtering of nickel oxide target on electron-hole recombination layer at 0.5 Pa, 70 °C and 700 W. Preparation of the metal oxide layer: Ammonia solution with pH 8 was coated onto the metal oxide precursor, with an ammonia solution added at a rate of 20 μL / cm. 2 The nickel oxide layer was obtained by spin coating at 3000 r / s for 20 s and annealing at 50℃ for 6 min. Preparation of self-assembled monolayer: A solution containing 2PACz was spin-coated onto a nickel oxide layer and annealed to form a self-assembled monolayer; Preparation of perovskite layer: CsBr and PbI2 were co-evaporated on a self-assembled monolayer to prepare a lead framework; FAI, FABr and MABr were dissolved in ethanol to obtain a cationic solution, which was spin-coated onto the lead framework and annealed to obtain a perovskite layer with a thickness of 460 nm. Preparation of passivation layer and electron transport layer: LiF and C60 were weighed into metal evaporation boat 1 and metal evaporation boat 2, and evaporated and deposited in sequence to obtain a LiF layer with a thickness of 1 nm and a C60 film layer with a thickness of 20 nm. Preparation of buffer layer: A 25 nm tin oxide layer was deposited on a C60 film; Preparation of a transparent conductive layer: Magnetron sputtering was performed on a tin oxide layer to obtain an ITO layer with a thickness of 100 nm; Electrode preparation: A first electrode and a second electrode were obtained by vapor deposition. The thickness of the first electrode was 350 nm, and the thickness of the second electrode was 350 nm. Preparation of antireflection layer: A LiF layer with a thickness of 100 nm was obtained by vapor deposition.

[0078] Example 2 The only difference between this embodiment and Embodiment 1 is that the annealing temperature in the step of preparing the metal oxide layer is 150°C and the annealing time is 15 min.

[0079] Example 3 The only difference between this embodiment and Embodiment 1 is that the annealing temperature in the step of preparing the metal oxide layer is 200°C and the annealing time is 3 min.

[0080] Example 4 The only difference between this embodiment and Embodiment 1 is that the annealing temperature in the step of preparing the metal oxide layer is 200°C and the annealing time is 20 min.

[0081] Example 5 The only difference between this embodiment and Embodiment 1 is that the pH of the ammonia water is 11, the annealing temperature is 200°C, and the annealing time is 20 min in the step of preparing the metal oxide layer.

[0082] Example 6 The only difference between this embodiment and Embodiment 2 is that the pH of the ammonia water in the step of preparing the metal oxide layer is 11.

[0083] Example 7 The only difference between this embodiment and Embodiment 2 is that the annealing time in the step of preparing the metal oxide layer is 20 minutes.

[0084] Example 8 The only difference between this embodiment and Embodiment 1 is that the pH of the ammonia water in the step of preparing the metal oxide layer is 12.

[0085] Example 9 The only difference between this embodiment and Embodiment 2 is that the pH of the ammonia water in the step of preparing the metal oxide layer is 12.

[0086] Example 10 The only difference between this embodiment and Embodiment 3 is that the pH of the ammonia water in the step of preparing the metal oxide layer is 12.

[0087] Example 11 The only difference between this embodiment and Example 10 is that the annealing time in the step of preparing the metal oxide layer is 20 min.

[0088] Comparative Example 1 The only difference between this comparative example and Example 1 is that the step of preparing the metal oxide layer is omitted.

[0089] Comparative Example 2 The only difference between this comparative example and Example 2 is that ammonia is replaced with hydrogen peroxide, and the pH is 4.5.

[0090] Comparative Example 3 The only difference between this comparative example and Example 3 is that the annealing temperature is replaced with 250°C.

[0091] Performance testing 1. Hydroxyl group coverage on the surface of the metal oxide layer X-ray photoelectron spectroscopy was used to test the surface of the metal oxide layer near the self-assembled molecular layer in the perovskite tandem solar cells of Examples 1 to 11 and Comparative Examples 1 to 3. The test results are shown in Table 1.

[0092] 2. Grain size of metal oxide layer The metal oxide layers in the perovskite tandem solar cells of Examples 1 to 11 and Comparative Examples 1 to 3 were tested using an X-ray diffractometer, and the test results are shown in Table 1.

[0093] 3. Surface roughness of the metal oxide layer The surfaces of the metal oxide layers near the self-assembled molecular layers in the perovskite tandem solar cells of Examples 1 to 11 and Comparative Examples 1 to 3 were tested using atomic force microscopy. The test results are shown in Table 1.

[0094] 4. Resistivity The metal oxide layers in the perovskite tandem solar cells of Examples 1 to 11 and Comparative Examples 1 to 3 were tested using a resistivity meter, and the test results are shown in Table 2.

[0095] 5. Carrier concentration and carrier mobility The metal oxide layers in the perovskite tandem solar cells of Examples 1 to 11 and Comparative Examples 1 to 3 were tested using a Hall effect tester, and the test results are shown in Table 2.

[0096] 6. Photoelectric properties The perovskite tandem solar cells of Examples 1-11 and Comparative Examples 1-3 were subjected to performance tests using the Halm testing and sorting equipment, including open-circuit voltage, fill factor, and photoelectric conversion efficiency. The Halm equipment, which simulates sunlight, is equipped with an electronic load, data acquisition, and calculation devices to test the electrical performance of photovoltaic devices (including solar cells). The calibrated light intensity of the tested solar cells was controlled at 1000 ± 5 W / m². The test results are shown in Table 3.

[0097] Table 1. Test results of hydroxyl coverage, roughness, and grain size of the first surface of the metal oxide layer in Examples 1-11 and Comparative Examples 1-3.

[0098] Table 2. Test results of resistivity and carrier mobility of metal oxide layers in Examples 1-11 and Comparative Examples 1-3

[0099] Table 3. Photoelectric performance test results of Examples 1 to 11 and Comparative Examples 1 to 3

[0100] As can be seen from the preparation method of Comparative Example 1, the hole transport layer of Comparative Example 1 is a nickel oxide layer with less hydroxyl coverage and smaller grain size, while the hole transport layers of Examples 1 to 11 of this application are nickel oxide layers with hydroxyl coverage of 7% to 25% and grain size of 5 nm to 10 nm. Compared with Comparative Example 1, the metal oxide layer (i.e., nickel oxide layer) of Examples 1 to 11 has a larger grain size and a higher hydroxyl coverage on its first surface, which is in the range of 7% to 25%. Therefore, the metal oxide layer improves the defects caused by the small grain size in the metal oxide precursor. At the same time, the metal oxide layer improves the stability and uniformity of the self-assembled molecular layer caused by the low hydroxyl coverage on the contact surface between the metal oxide precursor and the self-assembled molecular layer, thereby reducing defects in the self-assembled molecular layer and improving the contact performance between the two film layers. As can be seen from the data in Tables 2 and 3, the carrier mobility in the metal oxide layer of Examples 1 to 11 is improved, the resistivity is reduced, and the photoelectric performance of the perovskite solar cell is more excellent.

[0101] As shown in Table 1, the first surface of the metal oxide layer in both Example 11 and Comparative Example 2 has the same roughness, and the hydroxyl coverage of the first surface of the metal oxide layer is in the range of 7% to 25%. However, the grain size of their metal oxide layers is not in the range of 5 nm to 10 nm and is less than 5 nm. The 7 nm grain size of the metal oxide layer in Example 11 results in unsaturated coordinated metal ions (e.g., Ni²⁺) on the surface of the metal oxide layer. + / Ni³ + With fewer defects such as dangling bonds, oxygen vacancies, and hydroxyl agglomerations, there is less carrier recombination. Simultaneously, the lower grain boundary density in the metal oxide layer reduces carrier scattering and increases carrier transport efficiency. Data from Tables 2 and 3 show that the metal oxide layer in Example 11 exhibits improved carrier mobility and reduced resistivity, resulting in superior photoelectric performance of the perovskite solar cell.

[0102] As shown in Table 1, the first surface of the metal oxide layer in both Example 11 and Comparative Example 3 has the same roughness, and the grain size of the metal oxide layer is in the range of 5 nm to 10 nm. However, the hydroxyl coverage of the first surface of the metal oxide layer is not in the range of 7% to 25%, and is less than 7%. The 14% hydroxyl coverage of Example 11 is higher, therefore, Example 11 has more anchoring points in the self-assembled molecular layer and the metal oxide layer, making the interaction between the two layers stronger, improving the stability and uniformity of the self-assembled molecular layer, reducing defects in the self-assembled molecular layer and improving the contact performance between the two layers. As shown in Tables 2 and 3, the carrier mobility in the metal oxide layer of Example 11 is improved, the resistivity is reduced, and the photoelectric performance of the perovskite solar cell is superior.

[0103] As shown in Tables 1-3, in Examples 1-11, when the lattice size increases, there are fewer defects and less carrier recombination in the metal oxide layer. Simultaneously, the grain boundary density in the metal oxide layer is lower, resulting in reduced carrier scattering, higher carrier mobility, lower resistivity, and improved carrier transport efficiency in the metal oxide layer. However, when the grain size is too large, the hydroxyl coverage on the first surface of the metal oxide layer decreases. When the combined indicators of the lattice size and the hydroxyl coverage on the first surface of the metal oxide layer are better (Example 6), with fewer defects in the metal oxide layer, the higher hydroxyl coverage on the first surface leads to higher uniformity of the self-assembled molecular layer, reduces carrier recombination at the interface between the metal oxide layer and the self-assembled molecular layer, and results in higher photoelectric conversion efficiency of the perovskite solar cell.

[0104] The technical solutions disclosed in the embodiments of this application have been described in detail above. Specific examples have been used in this article to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the technical solutions and core inventive points of the embodiments of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A perovskite solar cell, characterized in that, The perovskite solar cell includes: A hole transport layer, wherein the hole transport layer includes a metal oxide layer, and the grain size of the metal oxide layer is 5 nm to 10 nm; A self-assembled molecular layer is disposed on a first surface of the metal oxide layer, wherein the hydroxyl group coverage of the first surface is 7% to 25%.

2. The perovskite solar cell according to claim 1, characterized in that, The roughness of the first surface is 4 nm to 8 nm; and / or, The carrier concentration of the metal oxide layer is 2.14 × 10⁻⁶. 19 / cm 3 ~4.50×10 19 / cm 3 The carrier mobility of the metal oxide layer is 0.366 cm⁻¹. 2 / vs~0.731 cm 2 / vs.

3. The perovskite solar cell according to claim 1, characterized in that, The metal oxide layer is made of at least one of nickel oxide, cobalt oxide, copper oxide, cuprous oxide, or tungsten oxide. The perovskite solar cell further includes a perovskite layer disposed on the surface of the self-assembled molecular layer away from the hole transport layer. The perovskite layer has the structural formula ABX3, where A is an A-site cation, B is a B-site cation, and X is an X-site anion. The A-site cation includes FA. + MA + Cs + K + Ca 2+ Zn 2+ Na + 、Rb + DMA + BA + PA + AA + BMIM + EA + or EDA 2+ At least one of the following, wherein the B-site cation includes Pb 2+ Ga 2+ and Sn 2+ At least one of the following, wherein the X-position anion includes I - F - ,Br - Cl - SCN - OCN - BF4 - TFSI - CF3 - CF3CO2 - COO - or SO3 - At least one of them; and / or, The material of the self-assembled molecular layer includes one or more of 4PACz, 4PADCB, MeO-2PACz, 2PACz or Me-4PACz.

4. The perovskite solar cell according to claim 3, characterized in that, The metal oxide layer is made of nickel oxide, which includes Ni. 2+ and Ni 3+ ; The perovskite layer includes the FA. + The MA + The I - The F - The Br - The Cl - The Pb 2+ At least one of them.

5. The perovskite solar cell according to claim 1, characterized in that, The perovskite solar cell also includes a hole-electron recombination layer, which and the self-assembled molecular layer are located on opposite sides of the hole transport layer.

6. The perovskite solar cell according to any one of claims 1-5, characterized in that, The perovskite solar cell is a perovskite tandem solar cell, comprising: a base cell, and a hole-electron recombination layer, a hole transport layer, a self-assembled molecular layer, a perovskite layer, an electron transport layer, and a first electrode sequentially stacked on the surface of the base cell; a second electrode, disposed on the base cell, wherein one of the first electrode and the second electrode is a positive electrode and the other is a negative electrode; or, The perovskite solar cell is a perovskite single-junction cell, which includes: a substrate, and a transparent conductive substrate, a hole transport layer, a self-assembled molecular layer, a perovskite layer, an electron transport layer, a transparent conductive layer, and a first electrode sequentially stacked on the surface of the substrate; and a second electrode, wherein the second electrode and the hole transport layer are disposed on different regions of the same side surface of the transparent conductive substrate, and one of the first electrode and the other of the second electrode is a positive electrode and the other is a negative electrode.

7. The perovskite solar cell according to claim 6, characterized in that, The bottom battery includes any one of the following: heterojunction battery, passivated contact battery, copper indium gallium selenide battery, and organic battery; and / or, The thickness of the hole transport layer is 10 nm to 25 nm.

8. A method for preparing a perovskite solar cell, characterized in that, The preparation method includes: Preparation of a metal oxide layer for hole transport: Ammonia is coated onto a metal oxide precursor and annealed to obtain the metal oxide layer. The grain size of the metal oxide layer is 5 nm to 10 nm. The metal oxide layer has a first surface with a hydroxyl coverage of 7% to 25%. The metal oxide layer and the metal oxide precursor are made of the same material but have different hydroxyl coverage and different grain sizes.

9. The preparation method according to claim 8, characterized in that, In the annealing step, the annealing temperature is 50℃~200℃, and the annealing time is 3 min~20 min.

10. The preparation method according to claim 9, characterized in that, In the step of coating the metal oxide precursor with ammonia, the pH of the ammonia is 8-12, and the addition volume is 8 μL / cm. 2 ~32 μL / cm 2 The roughness of the first surface is 4 nm to 8 nm.

11. The preparation method according to claim 10, characterized in that, In the step of coating the metal oxide precursor with ammonia, the spin coating speed is 500 r / s to 4000 r / s, and the spin coating time is 5 s to 30 s.

12. The preparation method according to claim 8, characterized in that, Before the step of coating the metal oxide precursor with ammonia, the step of preparing the hole transport layer further includes preparing the metal oxide precursor: an RF sputtering target, wherein the process conditions of the RF sputtering target are: sputtering pressure of 0.3 Pa to 1.0 Pa, sputtering temperature of 23°C to 100°C, and sputtering power of 100 W to 1100 W, and the target includes at least one of nickel oxide, cobalt oxide, copper oxide, cuprous oxide, or tungsten oxide.

13. A photovoltaic module, characterized in that, The photovoltaic module includes the perovskite solar cell as described in any one of claims 1-7 and the perovskite solar cell prepared by the preparation method described in any one of claims 8-12.

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