Silicon oxide layer film and preparation method and application thereof

Abstract

The invention provides a silicon oxide layer film and a preparation method and application thereof, the silicon oxide layer film is prepared by coating a precursor solution of a silicate ester compound on a substrate by using a solution method, and the silicon oxide layer film is applied to a perovskite solar cell with a formal structure, so that the compounding condition of a perovskite buried interface can be effectively improved, and the performance of the perovskite solar cell is improved. Therefore, the perovskite solar cell has better photoelectric conversion efficiency and stability.

Description

Technical Field

[0001] The invention belongs to the technical field of optoelectronic materials and devices, and in particular relates to a silicon oxide layer film and a preparation method and application thereof. Background Art

[0002] Perovskite materials have been widely studied and applied in important fields such as solar cells, light-emitting devices, and photodetectors due to their excellent and adjustable photoelectric properties. Performance research on perovskite materials and devices has long-term scientific and economic value. Among them, perovskite solar cells, as the representative of the third generation of thin-film solar cells, have the advantages of high theoretical photoelectric conversion efficiency, low cost, low energy consumption, and rich application scenarios. At present, its photoelectric conversion efficiency has exceeded 26%, but it is still a certain distance from its theoretical efficiency limit.

[0003] In perovskite solar cells (PSCs), the common "sandwich" structure is composed of an electron transport layer (ETL), a perovskite layer (PVK) and a hole transport layer (HTL). The interface contact between these layers has a direct impact on the performance and stability of the device. On the one hand, the inevitable charge trap states on the interface hinder charge extraction; on the other hand, the imperfect energy level arrangement leads to a large amount of non-radiative recombination losses. Therefore, the modification and adjustment of the surface / interface is one of the important methods to overcome these negative effects. Current research mainly focuses on the method of modifying the upper surface of the perovskite layer, which suppresses non-radiative recombination by passivating surface defects, promotes interfacial charge extraction, and enhances the stability of the perovskite film. However, there are few studies on the modification of the lower surface (buried interface) of the perovskite layer. In fact, the buried interface of the perovskite layer also has serious non-radiative recombination. The inhibition of the recombination of the lower interface is also crucial to achieve efficient and stable battery devices. Therefore, the interface engineering improvement of the perovskite bottom interface is an important strategy to further improve the performance of battery devices.

[0004] At present, the improvement strategies of perovskite bottom interface mainly include the following three categories:

[0005] 1) Solution method for preparing functional organic molecule modification layer (see references 1, 2 and 3) and two-dimensional perovskite (see references 4 and 5): This method uses functional molecules to modify or two-dimensional perovskite to treat the bottom interface of perovskite; before preparing the perovskite layer, a layer of functional molecule film or two-dimensional perovskite film is first prepared. Although this type of material can reduce the defects of the perovskite bottom interface crystal and the carrier defect recombination, these functional layers are easily destroyed by organic solvents (such as DMF and DMSO) in the perovskite precursor solution during the preparation of the perovskite layer.

[0006] 2) Solution method for preparing a porous insulator contact layer formed by aluminum oxide nanoplates (see reference 6): This method uses a porous insulating layer formed by aluminum oxide nanoplates to reduce the contact area between the perovskite and the bottom transport layer, thereby effectively reducing the non-radiative recombination at the interface. However, in this strategy, in order to achieve effective charge transfer, the coverage of the insulator is greatly limited. Therefore, many recombination centers continue to exist next to the pores at the interface, making it difficult to achieve the ideal effect.

[0007] 3) Atomic layer deposition method for preparing metal oxide dielectric layer (see references 7 and 8): This method uses metal oxides with good chemical stability and good corrosion resistance to solvents, such as aluminum oxide, hafnium aluminum oxide (HfAlO) and other materials, to form a dielectric oxide film by atomic layer deposition, isolating the direct contact between the perovskite film and the transport layer, thereby reducing the interface recombination; the disadvantages of this method are that, on the one hand, the device performance is very sensitive to the thickness of the dielectric layer, and on the other hand, the atomic layer deposition method has a slow deposition rate and high process cost, which is greatly limited in application.

[0008] It can be seen that although some research has been conducted in this field on the improvement strategies of the bottom interface of perovskite, they all have their limitations or shortcomings. Therefore, it is urgent to design a simple and effective bottom surface modification strategy to inhibit the recombination of the bottom interface of perovskite without affecting the charge transfer, so as to achieve high-efficiency perovskite solar cells.

[0009] References:

[0010] Cited literature 1: Xu W., Chen B., Zhang Z., et al. Multifunctional entinostatenhances the mechanical robustness and efficiency of flexible perovskitesolar cells and minimodules[J]. Nature Photonics, 2024, 18: 379-387.

[0011] Cited literature 2: Li M., Jiao B., Peng Y., et al. High-efficiency perovskitesolar cells with improved interfacial charge extraction by bridging molecules[J]. Advanced Materials, 2024.

[0012] Citation 3: Li Z., Jia C., Wan Z., et al. Hyperbranched polymerfunctionalized flexible perovskite solar cells with mechanical robustness andreduced lead leakage[J]. Nature Communications, 2023, 14: 6451.

[0013] Citation 4: Jang Y., Lee S., Yeom, K., et al. Intact 2D / 3D halide junctionperovskite solar cells via solid-phase in-plane growth[J]. Nature Energy, 2021, 6: 63-71.

[0014] Citation 5: Azmi R., Utomo D., Vishal B., et al. Double-side 2D / 3Dheterojunctions for inverted perovskite solar cells[J]. Nature, 2024, 628: 93-98.

[0015] Citation 6: Peng W., Mao K., Cai F., et al. Reducing nonradiativerecombination in perovskite solar cells with a porous insulator contact[J]. Science, 2023, 379: 683-690.

[0016] Citation 7: Yang, Y., Cheng, S., Zhu, X., et al. Inverted perovskite solarcells with over2,000h operational stability at 85℃ using fixed chargepassivation[J]. Nature Energy, 2024, 9: 37-46.

[0017] Cited literature 8: Zhang, L., Fang, M., Fu, L., et al. Ultrathin HfAlO ferroelectricsenhancing electron transport and perovskite solar cell performance [J]. Journal of Materials Research, 2021, 36: 1855-1865. Summary of the invention

[0018] Problem that the invention aims to solve

[0019] In order to solve the above problems, the present invention proposes a silicon oxide layer film and a preparation method and application thereof. The silicon oxide layer film is prepared by coating a precursor solution of a silicate compound on a substrate using a solution method, and applied to a formally structured perovskite solar cell. The recombination of the perovskite buried interface can be effectively improved, so that the perovskite solar cell has better photoelectric conversion efficiency and stability.

[0020] Solutions for solving problems

[0021] The present invention proposes a bottom surface improvement strategy for perovskite solar cells with simple processing, low cost and good effect, wherein an ultra-thin silicon oxide layer is introduced into the perovskite bottom interface (i.e., between the perovskite layer and the electron transport layer) of the formal perovskite solar cell, and the specific implementation method is as follows: a silicate precursor liquid is deposited onto the electron transport layer by spin coating or coating, and after heating, the silicate compounds in the silicate precursor liquid are hydrolyzed and condensed to form an amorphous silicon oxide layer.

[0022] [1]. A silicon oxide film, wherein the raw material for preparing the silicon oxide film comprises a silicate compound having the following structure:

[0023]

[0024] in:

[0025] R1 is methyl, ethyl, propyl or butyl;

[0026] R2 is methyl, ethyl, propyl or butyl;

[0027] R3 is methyl, ethyl, propyl or butyl;

[0028] R4 is methyl, ethyl, propyl or butyl.

[0029] [2] The silicon oxide layer thin film according to [1], wherein:

[0030] R1 is methyl or ethyl;

[0031] R2 is methyl or ethyl;

[0032] R3 is methyl or ethyl;

[0033] R4 is methyl or ethyl.

[0034] [3] The silicon oxide layer thin film according to [1] or [2], wherein:

[0035] R1, R2, R3 and R4 are all ethyl.

[0036] [4] A method for preparing a silicon oxide thin film according to any one of [1] to [3], comprising the following steps:

[0037] 1) dissolving the silicate compound in a solvent to obtain a silicate precursor solution;

[0038] 2) coating the silicate precursor solution in step 1) on the substrate, and then performing a heat treatment to obtain a silicon oxide layer film.

[0039] [5]. The preparation method according to [4], wherein in step 1), the solvent is a mixed solvent of alcohol and water.

[0040] [6]. The preparation method according to [4] or [5], wherein in step 1),

[0041] The concentration of the silicate compound in the silicate precursor solution is 0.5 to 5 mg / mL;

[0042] The silicate compound and potassium chloride are dissolved in a solvent, and the concentration of the potassium chloride in the silicate precursor solution is 0.5-2 mg / mL.

[0043] [7]. The preparation method according to any one of [4] to [6], wherein in step 2),

[0044] The heating temperature is 90-110° C.; and / or,

[0045] The heating time is 20 to 40 minutes.

[0046] [8] The preparation method according to any one of [4] to [7] is characterized in that the thickness of the obtained silicon oxide layer film is less than 5 nm.

[0047] [9] A perovskite solar cell with a formal structure, which comprises an ITO conductive substrate, an electron transport layer, a silicon oxide layer, a perovskite layer, a hole transport layer and a metal back electrode arranged in order from bottom to top;

[0048] Wherein, the silicon oxide layer comprises a silicon oxide layer thin film according to any one of [1]-[3] or a silicon oxide layer thin film prepared by the preparation method according to any one of [4]-[8].

[0049] 10. Use of the silicon oxide film according to any one of [1]-[3], or the silicon oxide film prepared by the preparation method according to any one of [4]-[8], or the perovskite solar cell according to [9] in the preparation of a photovoltaic device.

[0050] Effects of the Invention

[0051] 1) The present invention introduces a silicon oxide layer between the electron transport layer and the perovskite layer; on the one hand, the silicon oxide layer has complete and good conformal coverage on the surface of the electron transport layer, which can effectively reduce leakage current and improve the parallel resistance of the battery device; on the other hand, the silicon oxide layer allows electrons to tunnel through while blocking hole transmission and effectively suppresses non-radiative recombination at the interface, thereby achieving performance improvement of the perovskite solar cell; the perovskite solar cell device after the introduction of the silicon oxide layer obtains excellent photoelectric conversion efficiency and stability.

[0052] 2) The preparation method of the present invention has the advantages of simple process, low cost, good effect and large-scale preparation. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 . The conventional structure of a formal perovskite solar cell device (left) and the device structure after the silicon oxide layer is introduced into the present invention (right);

[0054] Figure 2 . Comparison of JV curves of perovskite solar cell devices of Example 1 and Comparative Example 1;

[0055] Figure 3 . Comparison of photoluminescence spectra of the perovskite film of Example 1 and Comparative Example 1;

[0056] Figure 4 .Comparison chart of the stability of the perovskite solar cell devices of Example 1 and Control Example 1. DETAILED DESCRIPTION

[0057] The following describes the embodiments of the present invention, but the present invention is not limited thereto. The present invention is not limited to the various structures described below, and various changes can be made within the scope of the invention claim, and the embodiments and examples obtained by appropriately combining the technical means disclosed in different embodiments and examples are also included in the technical scope of the present invention.

[0058] Unless otherwise stated, the units used in this specification are all international standard units, and the numerical values ​​and numerical ranges appearing in the present invention should be understood to include the inevitable systematic errors in industrial production.

[0059] In this specification, the numerical range expressed using "a numerical value A to a numerical value B" means a range including the endpoints numerical values ​​A and B.

[0060] In this specification, the numerical range expressed using "above" or "below" means a numerical range including the number.

[0061] In this specification, the word "may" includes both performing a certain process and not performing a certain process.

[0062] In the present specification, the use of "optional" or "optional / optionally" indicates that certain substances, components, execution steps, application conditions and other factors are used or not used.

[0063] In this specification, unless otherwise specified, the "normal temperature" or "room temperature" used generally refers to the temperature of 23±2°C.

[0064] In this specification, the unit names used are all international standard unit names, and unless otherwise stated, the "%" used indicates weight or mass percentage.

[0065] In this specification, "comprising", "having", "including" or "containing" may mean inclusive or open-ended, not excluding additional, uncited elements or method steps. At the same time, "comprising", "having", "including" or "containing" may also mean closed, excluding additional, uncited elements or method steps.

[0066] In this specification, "about" is used to define the numerical range and parameters of the present invention. All numerical values ​​are approximate, and the specific relevant numerical values ​​are presented as accurately as possible. Unless otherwise expressly stated, it should be understood that all ranges, quantities, values ​​and percentages used in the present invention are modified by "about". Here, "about" usually means that the actual value is within ±5%, ±3%, ±1% or ±0.5% of a particular value or range.

[0067] In this specification, the references to "some specific / preferred embodiments", "other specific / preferred embodiments", "embodiments", etc., mean that the specific elements (e.g., features, structures, properties and / or characteristics) described in connection with the embodiments are included in at least one embodiment described herein, and may or may not exist in other embodiments. In addition, it should be understood that the elements may be combined in various embodiments in any suitable manner.

[0068] <First aspect>

[0069] A first aspect of the present invention provides a silicon oxide film, wherein the raw material for preparing the silicon oxide film comprises a silicate compound having the following structure:

[0070]

[0071] in:

[0072] R1 is methyl, ethyl, propyl or butyl;

[0073] R2 is methyl, ethyl, propyl or butyl;

[0074] R3 is methyl, ethyl, propyl or butyl;

[0075] R4 is methyl, ethyl, propyl or butyl.

[0076] Preferably, R1 is methyl or ethyl; R2 is methyl or ethyl; R3 is methyl or ethyl; R4 is methyl or ethyl.

[0077] More preferably, R1, R2, R3 and R4 are all ethyl.

[0078] The silicate compound described in the present invention can be prepared by conventional methods or commercially available. The advantage of the present invention over the prior art is that the silicate compound is introduced into the silicate precursor solution to prepare the silicon oxide layer, thereby improving the photoelectric conversion efficiency of the perovskite solar cell and other optoelectronic devices using the silicon oxide layer, and making them work stably for a long time.

[0079] <Second Aspect>

[0080] A second aspect of the present invention provides a method for preparing the silicon oxide layer thin film described in the first aspect, comprising the following steps:

[0081] 1) dissolving the silicate compound in a solvent to obtain a silicate precursor solution;

[0082] 2) coating the silicate precursor solution in step 1) on the substrate, and then performing a heat treatment to obtain a silicon oxide layer film.

[0083] In some preferred embodiments, the solvent is a mixed solvent of alcohol and water, the alcohol is selected from one or more of methanol, ethanol, isopropanol, n-butanol, and tert-butanol, and the volume ratio of the alcohol to water is 1:0.2-4; preferably, the solvent is a mixed solvent of ethanol and water, and the volume ratio of ethanol to water is 1:0.5-2, for example, it can be 1:0.5, 1:0.8, 1:1, 1:1.2, 1:1.5, 1:1.8, 1:2, etc.; more preferably, the solvent is a mixed solvent of ethanol and water in a volume ratio of 1:1.

[0084] In some specific embodiments, the concentration of the silicate compound in the silicate precursor solution is 0.5-5 mg / mL, preferably 0.8-4 mg / mL, more preferably 1-3 mg / mL, for example, it can be 0.6 mg / mL, 0.9 mg / mL, 1.5 mg / mL, 2 mg / mL, 2.5 mg / mL, 3 mg / mL, 3.5 mg / mL, 4.5 mg / mL, etc.

[0085] In some specific embodiments, the silicate compound and potassium chloride are dissolved in a solvent, and the concentration of potassium chloride in the silicate precursor solution is 0.5-2 mg / mL, preferably 0.5-1.5 mg / mL, and more preferably 0.6-1.2 mg / mL, for example, it can be 0.6 mg / mL, 0.75 mg / mL, 0.9 mg / mL, 1.1 mg / mL, 1.3 mg / mL, 1.5 mg / mL, 1.7 mg / mL, 1.9 mg / mL, etc.

[0086] In some specific embodiments, the coating is selected from one or more of spin coating, slot extrusion coating, evaporation, blade coating and screen printing, preferably spin coating or slot extrusion coating.

[0087] In some specific embodiments, the spin coating conditions include: a spin coating speed of 2000-6000 r / min, preferably 3000-5000 r / min, more preferably 3500-4500 r / min; a spin coating time of 5-40 s, preferably 10-30 s, more preferably 15-25 s.

[0088] In other specific embodiments, the conditions of the slot extrusion coating include: a coating speed of 1 to 10 mm / s, preferably 1 to 8 mm / s, and more preferably 2 to 5 mm / s.

[0089] In some specific embodiments, the heating temperature is 90-110°C, preferably 95-105°C, for example, it can be 92°C, 94°C, 96°C, 98°C, 100°C, 102°C, 104°C, 106°C, 108°C, etc.

[0090] In some specific embodiments, the heating time is 20 to 40 minutes, preferably 25 to 35 minutes, for example, 22 minutes, 24 minutes, 26 minutes, 28 minutes, 30 minutes, 32 minutes, 34 minutes, 36 minutes, 38 minutes, etc.

[0091] In some specific embodiments, the silicon oxide film prepared in the present invention has a thickness of less than 5 nm, preferably less than 3 nm, more preferably less than 2 nm, and further preferably 1 to 2 nm.

[0092] <Third Aspect>

[0093] The third aspect of the present invention provides a formally structured perovskite solar cell, which includes an ITO conductive substrate, an electron transport layer, a silicon oxide layer, a perovskite layer, a hole transport layer and a metal back electrode arranged in sequence from bottom to top;

[0094] Wherein, the silicon oxide layer comprises the silicon oxide layer thin film described in the first aspect or the silicon oxide layer thin film prepared by the preparation method described in the second aspect.

[0095] In some specific embodiments, the ITO conductive substrate includes an ITO (indium-doped tin oxide) transparent conductive layer, a flexible substrate (eg, a PET flexible substrate) or a rigid substrate (eg, a glass substrate) adjacent to the ITO transparent conductive layer.

[0096] In some specific embodiments of the present invention, the electron transport layer, the perovskite layer, the hole transport layer and the metal back electrode can be made of conventional materials.

[0097] In some specific embodiments, the material of the electron transport layer includes one or more of SnO2, ZnO, TiO2, and CeO2, preferably SnO2.

[0098] In some specific embodiments, the material of the perovskite layer is a metal halide perovskite, and the crystal structure of the metal halide perovskite is ABX3, wherein A represents a monovalent organic cation (MA + , FA + etc.), metal cations (Cs + , Rb + etc.) or a combination thereof, B represents a divalent metal cation (Pb 2+ Sn 2+ ), X represents a halogen anion (I - Br - or Cl - ). Preferably, the structure of the material of the perovskite layer of the present invention is Rb x FA 1-xPbI3.

[0099] In some specific embodiments, the material of the hole transport layer includes one or more of 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene (spiro-OMeTAD), poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), poly(3-hexylthiophene-2,5-diyl) (P3HT), and nickel oxide (NiO), preferably spiro-OMeTAD.

[0100] In some specific embodiments, the material of the metal back electrode includes any one of gold, silver, and copper, preferably gold.

[0101] In some specific embodiments, the electron transport layer, the perovskite layer and the hole transport layer can be prepared according to conventional methods in the art, for example, by water bath deposition, solution spin coating, spraying, blade coating, slit extrusion coating, evaporation, etc.

[0102] In some specific embodiments, the metal back electrode is prepared by at least one of vacuum sputtering, vacuum evaporation and solution method (such as spin coating, blade coating, slit extrusion coating, inkjet printing, etc.).

[0103] In some specific embodiments, the thickness of the electron transport layer is 10 to 30 nm, the thickness of the perovskite layer is 600 to 1000 nm, the thickness of the hole transport layer is 150 to 250 nm, and the thickness of the metal back electrode is 60 to 100 nm.

[0104] <Fourth Aspect>

[0105] The fourth aspect of the present invention provides a use of the silicon oxide layer film according to the first aspect, or the silicon oxide layer film prepared by the preparation method according to the second aspect, or the perovskite solar cell according to the third aspect in the preparation of a photoelectric device.

[0106] In some specific embodiments, the optoelectronic device includes a solar cell, a light emitting diode, a photodetector, a photosensitive diode, a laser, and the like.

[0107] Example

[0108] The embodiments of the present invention will be described in detail below in conjunction with the examples, but those skilled in the art will appreciate that the following examples are only used to illustrate the present invention and should not be considered to limit the scope of the present invention. If no specific conditions are specified in the examples, they are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be obtained commercially.

[0109] Embodiment 1:

[0110] The tetraethyl silicate solution is spin-coated or coated on the electron transport layer to prepare a silicon oxide layer, and a perovskite solar cell is further prepared, and the photovoltaic parameters of the cell are tested.

[0111] The structure of this battery adopts the formal nip type structure, such as Figure 1 As shown, it includes an ITO conductive substrate, an electron transport layer, a silicon oxide layer, a perovskite layer, a hole transport layer and a metal back electrode. In an embodiment of the present invention, the ITO conductive substrate includes a PET flexible substrate (thickness is about 0.2 mm) and an ITO (indium-doped tin oxide) transparent conductive layer (thickness is about 200 nm).

[0112] The preparation process of perovskite solar cells is as follows:

[0113] Step 1: Clean the ITO conductive substrate

[0114] The ITO conductive substrate was immersed in a cleaning agent, ultrapure water, anhydrous ethanol and isopropanol solvents in turn, and ultrasonically cleaned for at least 10 minutes each time. Then, nitrogen was used to blow dry the residual solvent on the surface, and then it was transferred to a UV ozone device for 20 minutes to remove the residual organic matter on the surface.

[0115] Step 2: Preparation of SnO2 electron transport layer

[0116] First, prepare stannous sulfate solution: dissolve 2.5 g urea, 75 μL thioglycolic acid, and 0.4 g stannous sulfate in 1200 mL deionized water.

[0117] The cleaned ITO conductive substrate was then immersed in a 70°C stannous sulfate solution for 3 hours, and an electron transport layer (thickness of about 20 nm) was deposited using a water bath method. After the water bath, deionized water was used for ultrasonic cleaning for 5 minutes, and then it was blown dry with nitrogen. Finally, it was heated at 180°C in air for 1 hour, cooled to room temperature, and then transferred to a UV ozone device for treatment for 20 minutes.

[0118] Step 3: Prepare the silicon oxide layer

[0119] Tetraethyl silicate solution (2 mg tetraethyl silicate and 0.75 mg potassium chloride, dissolved in 1 mL of a mixed solvent of ethanol and water (volume ratio 1:1)) was spin-coated on the electron transport layer at a speed of 4000 r / min for 20 seconds. After spin coating, the layer was heated at 100° C. in air for 30 minutes to obtain a silicon oxide layer (with a thickness of about 1 to 2 nm).

[0120] Alternatively, a slit extrusion coating method (suitable for large areas) is used to coat the electron transport layer with a tetraethyl silicate solution (30 mg of tetraethyl silicate and 11 mg of potassium chloride, dissolved in 10 mL of a mixed solvent of ethanol and water (volume ratio 1:1)), with a distance of 100 μm between the blade and the substrate, a coating speed of 3.5 mm / s, and heating at 100°C in air for 30 minutes after coating to obtain a silicon oxide layer (with a thickness of about 1 to 2 nm).

[0121] Among them, the molecular structure of tetraethyl silicate is:

[0122] Step 4: Preparation of Rb 0.05 FA 0.95 PbI3 perovskite layer

[0123] Two-step solution method for preparing perovskite layer:

[0124] First, prepare a two-step precursor solution: 1) dissolve lead iodide and doped rubidium chloride powder in a mixed solution of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) (volume ratio 9:1) to obtain a lead iodide precursor solution with a concentration of 691.5 mg / mL and 9 mg / mL doped rubidium chloride; 2) dissolve iodoformamidine (CH(NH2)2I) and chloromethylamine (CH3NH3Cl) powder in isopropanol to obtain an ammonium salt precursor solution with a concentration of 84 mg / mL iodoformamidine and 14 mg / mL chloromethylamine.

[0125] Then, the perovskite layer film is prepared: first, the lead iodide precursor solution is spin-coated on the silicon oxide layer, and then annealed after the spin coating to obtain the lead iodide film; then, the ammonium salt precursor solution is spin-coated on the lead iodide film, and after the spin coating, it is heated in air at 150°C for 15 minutes to obtain Rb 0.05 FA 0.95 PbI3 perovskite film (thickness is about 800nm).

[0126] Step 5: Preparation of spiro-OMeTAD hole transport layer

[0127] Solution method for preparing hole transport layer:

[0128] The hole transport material spiro-OMeTAD powder was dissolved in chlorobenzene (concentration of 80 mg / mL), and tetra-tert-butylpyridine and lithium bis(trifluoromethanesulfonylimide) additives were added to obtain a hole transport layer solution; the solution was spin-coated on the above-mentioned perovskite layer to obtain a spiro-OMeTAD hole transport layer film (thickness of about 200 nm).

[0129] Step 6: Prepare the metal back electrode

[0130] Preparation of gold electrode by evaporation method:

[0131] By using the vacuum thermal evaporation method, an 80nm thick gold electrode was deposited on the hole transport layer film to obtain a complete perovskite solar cell device.

[0132] Comparative Example 1:

[0133] Compared with Example 1, tetraethyl silicate was not added to the solution in step 3, and the other steps were the same as those in Example 1.

[0134] Table 1. Photovoltaic parameters of devices in Example 1 and Comparative Example 1

[0135] Open circuit voltage(V) <![CDATA[Short-circuit current density (mA cm -2 )]]> Fill factor (%) Photoelectric conversion efficiency (%) Example 1 1.187 25.66 82.15 25.03 Comparative Example 1 1.166 25.34 79.36 23.44

[0136] As shown in Table 1, by comparing the performance parameters of solar cells with the introduction of a silicon oxide layer or a modified layer without silicate compounds, the photoelectric conversion efficiency of the perovskite solar cell of Example 1 is significantly improved from 23.44% to 25.03%. The main factors for the improvement of the photoelectric conversion efficiency are the increase in open circuit voltage and fill factor. The increase in open circuit voltage and fill factor comes from the suppression of non-radiative recombination at the bottom interface of the perovskite.

[0137] Depend on Figure 2 It can be seen that the current density of the embodiment and the control example both decreases slowly at first and then decreases rapidly with the increase of voltage; at the same voltage, the current density of the embodiment is greater than that of the control example; the improvement of the short-circuit current density lies in the fact that the silicon oxide layer has the function of blocking electron backflow.

[0138] Depend on Figure 3 It can be seen that after the silicon oxide layer is introduced between the perovskite layer and the electron transport layer in the perovskite solar cell in the embodiment, the enhancement of the photoluminescence intensity indicates that the interface defects are effectively passivated and the non-radiative recombination induced by the defect state is weakened.

[0139] Depend on Figure 4 It can be seen that after hundreds of hours of continuous stability testing, the efficiency attenuation of the embodiment is significantly different from that of the control example, and the stability of the perovskite solar cell of the present invention is greatly improved.

[0140] It should be noted that, although the technical solution of the present invention is introduced with specific examples, those skilled in the art will appreciate that the present invention should not be limited thereto.

[0141] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A silicon oxide thin film, characterized in that: The raw materials for preparing the silicon oxide layer thin film include silicate compounds with the following structure: in: R1 is methyl, ethyl, propyl or butyl; R2 is methyl, ethyl, propyl or butyl; R3 is methyl, ethyl, propyl or butyl; R4 is methyl, ethyl, propyl or butyl.

2. The silicon oxide thin film according to claim 1, characterized in that: R1 is methyl or ethyl; R2 is methyl or ethyl; R3 is methyl or ethyl; R4 is methyl or ethyl.

3. The silicon oxide layer thin film according to claim 1 or 2, characterized in that: R1, R2, R3 and R4 are all ethyl.

4. A method for preparing a silicon oxide layer thin film according to any one of claims 1 to 3, comprising the following steps: 1) dissolving the silicate compound in a solvent to obtain a silicate precursor solution; 2) coating the silicate precursor solution in step 1) on the substrate, and then performing a heat treatment to obtain a silicon oxide layer film.

5. The preparation method according to claim 4, characterized in that: In step 1), The solvent is a mixed solvent of alcohol and water.

6. The preparation method according to claim 4 or 5, characterized in that: In step 1), The concentration of the silicate compound in the silicate precursor solution is 0.5 to 5 mg / mL; The silicate compound and potassium chloride are dissolved in a solvent, and the concentration of the potassium chloride in the silicate precursor solution is 0.5-2 mg / mL.

7. The preparation method according to any one of claims 4 to 6, characterized in that: In step 2), The heating temperature is 90-110° C.; and / or, The heating time is 20 to 40 minutes.

8. The preparation method according to any one of claims 4 to 7, characterized in that: The thickness of the obtained silicon oxide layer thin film is less than 5 nm.

9. A perovskite solar cell with a formal structure, which comprises an ITO conductive substrate, an electron transport layer, a silicon oxide layer, a perovskite layer, a hole transport layer and a metal back electrode arranged in sequence from bottom to top; in, The silicon oxide layer comprises a silicon oxide layer thin film according to any one of claims 1 to 3 or a silicon oxide layer thin film prepared by the preparation method according to any one of claims 4 to 8.

10. Use of the silicon oxide thin film according to any one of claims 1 to 3, or the silicon oxide thin film prepared by the preparation method according to any one of claims 4 to 8, or the perovskite solar cell according to claim 9 in preparing a photoelectric device.

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