Perovskite / silicon tandem solar cell and preparation method thereof

Abstract

The application provides a perovskite / silicon laminated solar cell and a preparation method thereof. The perovskite / silicon laminated solar cell comprises, in sequence along a first direction, a silicon substrate, a second conductive oxide layer, a nanoparticle layer, a first conductive oxide layer, a hole transport layer and a perovskite layer. The nanoparticle layer comprises nanoparticles, and the particle size of the nanoparticles ranges from 50 nm to 300 nm. The side of the nanoparticle layer away from the silicon substrate has nano-sized protrusions formed by accumulation of the nanoparticles. The height of the protrusions is 50-300 nm, and the distance between adjacent two protrusions is 50-300 nm. The thickness of the second conductive oxide layer is greater than that of the first conductive oxide layer. The perovskite / silicon laminated solar cell has excellent short-circuit current density, open-circuit voltage, fill factor and photoelectric conversion efficiency.

Description

Technical Field

[0001] This invention belongs to the field of solar cell technology, specifically relating to a perovskite / silicon tandem solar cell and its preparation method. Background Technology

[0002] Perovskite / silicon tandem solar cells are a novel type of photovoltaic device based on a vertically stacked structure of perovskite material and monocrystalline silicon cells, and are widely used in the field of high-efficiency photovoltaic power generation. However, in existing technologies, it is difficult to achieve conformal coverage of the perovskite layer on the silicon substrate, which easily leads to local exposure or void defects. Furthermore, the interface impedance between the perovskite layer and the hole transport layer (HTL) is high, resulting in low carrier transport efficiency. Consequently, perovskite / silicon tandem solar cells generally suffer from performance degradation issues such as short-circuit current density, open-circuit voltage, fill factor, and photoelectric conversion efficiency. Summary of the Invention

[0003] This invention provides a perovskite / silicon tandem solar cell and its fabrication method, which is beneficial for improving the short-circuit current density, open-circuit voltage, fill factor, and photoelectric conversion efficiency of perovskite / silicon tandem solar cells.

[0004] In a first aspect, the present invention provides a perovskite / silicon tandem solar cell, comprising a silicon substrate, a second conductive oxide layer, a nanoparticle layer, a first conductive oxide layer, a hole transport layer, and a perovskite layer sequentially stacked along a first direction; the nanoparticle layer comprises nanoparticles with a particle size ranging from 50 to 300 nm; the nanoparticle layer has nanoscale protrusions on the side opposite to the silicon substrate, the protrusions being formed by the accumulation of the nanoparticles, the height of the protrusions being 50 to 300 nm, and the spacing between two adjacent protrusions being 50 to 300 nm; the thickness of the second conductive oxide layer is greater than the thickness of the first conductive oxide layer.

[0005] According to one embodiment of the present invention, the thickness of the first conductive oxide layer is x, where 0 < x ≤ 20 nm.

[0006] According to one embodiment of the present invention, the first conductive oxide layer comprises one or more of indium tin oxide, indium zinc oxide, aluminum-doped zinc oxide, and indium gallium zinc oxide; and / or, the second conductive oxide layer comprises one or more of indium tin oxide, indium zinc oxide, aluminum-doped zinc oxide, and indium gallium zinc oxide.

[0007] According to one embodiment of the present invention, the silicon substrate has a micron-sized pyramidal textured surface on the side near the second conductive oxide layer; and / or, the nanoparticles include metal nanoparticles and / or non-metal nanoparticles.

[0008] According to one embodiment of the present invention, the metal nanoparticles include one or more of gold, silver, and copper; and / or, the non-metal nanoparticles include one or more of aluminum oxide, zinc oxide, and silicon dioxide.

[0009] According to one embodiment of the present invention, the perovskite / silicon tandem solar cell includes a silicon substrate, a first passivation layer, a doped layer, a second conductive oxide layer, a nanoparticle layer, a first conductive oxide layer, a hole transport layer, a perovskite layer, a second passivation layer, an electron transport layer, a buffer layer, a protective layer, a third conductive oxide layer, and an electrode, which are sequentially stacked along a first direction.

[0010] Secondly, embodiments of the present invention also provide a method for preparing the above-mentioned perovskite / silicon tandem solar cell, comprising the following steps:

[0011] S1. A silicon substrate is provided, the silicon substrate having opposing first and second surfaces;

[0012] S2. A second conductive oxide layer is formed on the first surface of the silicon substrate;

[0013] S3. A nanoparticle layer is formed on the side of the second conductive oxide layer opposite to the silicon substrate;

[0014] S4. A first conductive oxide layer is formed on the side of the nanoparticle layer opposite to the silicon substrate;

[0015] S5. A hole transport layer is formed on the side of the first conductive oxide layer opposite to the silicon substrate;

[0016] S6. A perovskite layer is formed on the side of the hole transport layer away from the silicon substrate to obtain the perovskite / silicon tandem solar cell.

[0017] According to one embodiment of the present invention, the process of forming a first conductive oxide layer on the side of the nanoparticle layer opposite to the silicon substrate includes: forming a first conductive oxide layer on the side of the nanoparticle layer opposite to the silicon substrate using an atomic layer deposition process.

[0018] According to one embodiment of the present invention, before the step of forming a hole transport layer on the side of the first conductive oxide layer opposite to the silicon substrate, the method further includes: performing plasma cleaning on the first conductive oxide layer using plasma gas.

[0019] According to one embodiment of the present invention, the plasma cleaning time is 5-10 min; and / or, the plasma gas includes helium; and / or, the plasma cleaning pressure is 30 Pa-40 Pa.

[0020] This invention provides a perovskite / silicon tandem solar cell and its fabrication method. The perovskite / silicon tandem solar cell comprises a silicon substrate, a second conductive oxide layer, a nanoparticle layer, a first conductive oxide layer, a hole transport layer, and a perovskite layer, sequentially stacked along a first direction. The nanoparticle layer comprises nanoparticles with a particle size ranging from 50 to 300 nm. On the side of the nanoparticle layer facing away from the silicon substrate, there are nanoscale protrusions formed by the accumulation of nanoparticles. The height of the protrusions is 50-300 nm, and the spacing between adjacent protrusions is 50-300 nm. The thickness of the second conductive oxide layer is greater than the thickness of the first conductive oxide layer. In the above-described perovskite / silicon tandem solar cell system, the protrusions formed by the nanoparticles effectively enhance the anchoring ability of the perovskite solution, enabling the perovskite layer to achieve conformal coverage, thereby significantly improving the coverage uniformity of the perovskite layer. Simultaneously, the first conductive oxide layer facilitates the uniform adsorption of the hole transport layer, improving the carrier transport efficiency. This improves the short-circuit current density, open-circuit voltage, fill factor, and photoelectric conversion efficiency of perovskite / silicon tandem solar cells. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of a perovskite / silicon tandem solar cell according to an embodiment of the present invention;

[0022] Figure 2 The current density-voltage characteristic curves of the perovskite / silicon tandem solar cells in Example 1 and Comparative Example 1 of this invention are shown.

[0023] Explanation of reference numerals in the attached figures:

[0024] 1-First passivation layer; 2-Doped layer; 3-Second conductive oxide layer; 4-Nanoparticle layer; 5-First conductive oxide layer; 6-Hole transport layer; 7-Perovskite layer; 8-Second passivation layer; 9-Electron transport layer; 10-Buffer layer; 11-Protective layer; 12-Third conductive oxide layer; 13-Electrode; 14-Silicon substrate. Detailed Implementation

[0025] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below. The specific embodiments listed below are merely descriptions of the principles and features of the present invention, and the examples are only for explaining the present invention and are not intended to limit the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] In related technologies, it is difficult to achieve conformal coverage of the perovskite layer on the silicon substrate in the existing technology, and the interface impedance between the perovskite layer and the hole transport layer (HTL) is high, resulting in low carrier transport efficiency. This leads to the general performance degradation of perovskite / silicon tandem solar cells in terms of short-circuit current density, open-circuit voltage, fill factor, and photoelectric conversion efficiency, which urgently needs to be solved.

[0027] Specifically, the textured pyramid size of traditional monocrystalline silicon solar cells is typically 3-10 μm, while the thickness of the perovskite film is only 0.5-1 μm. When fabricating perovskite-silicon tandem solar cells using traditional solution methods, the textured pyramid makes it difficult to achieve conformal coverage of the perovskite film. Under standard processes, the pyramid tips are easily exposed, and voids can form at the bottom under high concentration and low rotation speed conditions, making process balancing difficult. While vapor deposition can achieve conformal coverage, its perovskite crystallinity is poor, and both time and economic costs are higher.

[0028] To achieve better coverage of perovskite films on silicon-based solar cells, existing solutions mainly include reducing the height of the textured pyramids and using submicron, planar, or nanostructures. However, these methods all reduce the light-trapping effect of the silicon-based solar cell, leading to severe current mismatch and affecting the overall short-circuit current. Another solution is to fill the base of the pyramid with perovskite or other semiconductor materials to reduce the exposed pyramid height, followed by spin-coating of the perovskite film.

[0029] According to the inventors' long-term research, anchoring of perovskite solutions requires imperfections on the solid surface, which create a relatively large energy barrier. During the spin coating process of perovskite precursors, if the surface of the microporous pyramid lacks any imperfections, the precursor solution will be difficult to retain at the tip under the influence of centrifugal and gravitational forces. Island-like nanoparticles, however, can act as typical imperfection areas, giving them higher wettability.

[0030] In view of this, embodiments of the present invention provide a perovskite / silicon tandem solar cell, comprising a silicon substrate, a second conductive oxide layer, a nanoparticle layer, a first conductive oxide layer, a hole transport layer, and a perovskite layer stacked sequentially along a first direction; the nanoparticle layer comprises nanoparticles with a particle size range of 50-300 nm; the nanoparticle layer has nanoscale protrusions on the side opposite to the silicon substrate, the protrusions being formed by the accumulation of nanoparticles, the height of the protrusions being 50-300 nm, the spacing between two adjacent protrusions being 50-300 nm, and the thickness of the second conductive oxide layer being greater than the thickness of the first conductive oxide layer.

[0031] In the aforementioned perovskite / silicon tandem solar cell system, the perovskite / silicon tandem solar cell exhibits excellent short-circuit current density, open-circuit voltage, fill factor, and photoelectric conversion efficiency. The reason for this is that: 1) "Surface defects" are created by introducing nanoparticles (particle size range of 50-300 nm) onto the surface of the second conductive oxide layer away from the silicon substrate. Specifically, nanoscale protrusions are formed on the side of the nanoparticle layer away from the silicon substrate, with a height of 50-300 nm and a spacing of 50-300 nm between adjacent protrusions. The presence of the first conductive oxide layer enhances the wettability of the second conductive oxide layer, facilitating conformal coverage of the perovskite layer on the hole transport layer and thus significantly improving the uniformity of the perovskite layer's coverage. 2) By depositing the first conductive oxide layer on the surface of the nanoparticle layer, on the one hand, the first conductive oxide layer can hydroxylate the nanoparticle surface, providing more -OH groups to promote the anchoring of the hole transport layer, forming covalent and coordination bonds, which is beneficial for the uniform adsorption of the hole transport layer. On the other hand, the first conductive oxide layer provides a low-impedance transport channel for charge carriers, improving the carrier transport efficiency. Therefore, the aforementioned perovskite / silicon tandem solar cell possesses excellent short-circuit current density, open-circuit voltage, fill factor, and photoelectric conversion efficiency.

[0032] In the embodiments of the present invention, the particle size range of the nanoparticles can be measured by conventional methods in the art, such as observing the cross-section of the nanoparticles using a scanning electron microscope.

[0033] In the embodiments of the present invention, the height and spacing of the protrusions can be observed on the surface and cross-section of the thin film using an atomic force microscope and a scanning electron microscope, respectively, and then the height and distance of the protrusions can be calculated.

[0034] For example, the particle size of the nanoparticles can be 50nm, 60nm, 80nm, 100nm, 150nm, 200nm, 230nm, 260nm or 300nm, etc.

[0035] For example, the height of the protrusion can be 50nm, 60nm, 80nm, 100nm, 150nm, 200nm, 230nm, 260nm or 300nm, etc.

[0036] For example, the spacing between two adjacent protrusions can be 50nm, 60nm, 80nm, 100nm, 150nm, 200nm, 230nm, 260nm or 300nm, etc.

[0037] In some embodiments, in addition to depositing nanoparticles on the second conductive oxide layer, columnar nanoarrays or bandgap-matched semiconductor nanoparticles can also be deposited on the second conductive oxide layer, which increases light transmittance while retaining light scattering.

[0038] In some embodiments, the thickness of the first conductive oxide layer is x, where 0 < x ≤ 20 nm, which helps to further improve the coverage uniformity and carrier transport efficiency of the perovskite layer.

[0039] For example, the thickness x of the first conductive oxide layer can be 0.5nm, 1nm, 5nm, 10nm, 12nm, 14nm, 16nm, 18nm or 20nm, etc.

[0040] In some embodiments, the first conductive oxide layer includes one or more of indium tin oxide, indium zinc oxide, aluminum-doped zinc oxide, and indium gallium zinc oxide, which is beneficial to further improve light absorption efficiency and carrier transport efficiency.

[0041] In some embodiments, the second conductive oxide includes one or more of indium tin oxide, indium zinc oxide, aluminum-doped zinc oxide, and indium gallium zinc oxide, which is beneficial for further improving light absorption efficiency and carrier transport efficiency.

[0042] In this embodiment of the invention, the silicon substrate has a micron-sized pyramidal textured surface structure on the side near the nanoparticle layer.

[0043] In some embodiments, the height of the pyramidal velvet structure is 3-10 μm.

[0044] In some embodiments, the nanoparticles include metallic nanoparticles and / or non-metallic nanoparticles.

[0045] In some embodiments, the metal nanoparticles include one or more of gold, silver, and copper.

[0046] In some embodiments, the non-metallic nanoparticles include one or more of aluminum oxide, zinc oxide, and silicon dioxide.

[0047] In some embodiments, the perovskite / silicon tandem solar cell includes a silicon substrate, a first passivation layer, a doped layer, a second conductive oxide layer, a nanoparticle layer, a first conductive oxide layer, a hole transport layer, a perovskite layer, a second passivation layer, an electron transport layer, a buffer layer, a protective layer, a third conductive oxide layer, and an electrode, which are sequentially stacked along a first direction.

[0048] In some embodiments, the first passivation layer includes an intrinsic hydrogenated amorphous silicon layer, which can provide effective electric field enhancement and interface passivation without affecting optical performance, thereby further improving the photoelectric conversion efficiency and long-term stability of perovskite / silicon tandem solar cells.

[0049] In some implementations, the second passivation layer, including an intrinsic hydrogenated amorphous silicon layer, can provide effective electric field enhancement and interface passivation without affecting optical performance, thereby further improving the photoelectric conversion efficiency and long-term stability of perovskite / silicon tandem solar cells.

[0050] In some implementations, the doped layer includes an N-type doped layer and / or a P-type doped layer.

[0051] In some embodiments, the third conductive oxide includes one or more of indium tin oxide, indium zinc oxide, aluminum-doped zinc oxide, and indium gallium zinc oxide, which is beneficial for further improving light absorption efficiency and carrier transport efficiency.

[0052] In some implementations, the core function of the hole transport layer (HTL layer) is to efficiently extract holes generated in the perovskite layer and directionally transport them to the electrode. The hole transport layer includes 4-methylphenyl-2-phenyl-5-phenyloxazole (Me-4PACz) and 4-methoxyphenyl-2-phenyl-5-phenyloxazole (MeO-2PACz).

[0053] In some implementations, the mass ratio of Me-4PACz to MeO-2PACz is 3:(1~1.5). This helps to balance the energy level matching and mobility of the two materials. Compared with single materials, blending can reduce the "trapped states" of hole transport and improve carrier transport efficiency.

[0054] In some embodiments, the perovskite layer has a three-dimensional perovskite structure of the general formula ABX3, wherein A is selected from... One or more of them, B is selected from X includes .

[0055] In some embodiments, the electron transport layer includes one or more of fullerene, methyl [6,6]-phenyl-C61-butyrate, carbon nanotubes, and graphene.

[0056] In some embodiments, the buffer layer comprises 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP).

[0057] In some implementations, the protective layer includes SnO. x It is beneficial for physical barrier protection, carrier regulation, and interface optimization.

[0058] In some embodiments, the electrode includes a metal electrode, which may be one or more of silver, copper, and gold, and can effectively reduce the electrode resistance, thereby improving the current collection efficiency and the electrical performance of the perovskite / silicon tandem solar cell.

[0059] In some embodiments, the thickness of the silicon substrate is 100-200 μm, the thickness of the first passivation layer is 15-50 nm, the thickness of the doped layer is 5-20 nm, the thickness of the second conductive oxide layer is 10-30 nm, the thickness of the hole transport layer is 1-5 nm, the thickness of the perovskite layer is 500-1000 nm, the thickness of the second passivation layer is 10-20 nm, the thickness of the electron transport layer is 10-30 nm, the thickness of the buffer layer is 5-8 nm, the thickness of the protective layer is 10-20 nm, the thickness of the third conductive oxide layer is 50-150 nm, and the thickness of the electrode is 200-350 nm.

[0060] For example, the thickness of the silicon substrate can be 100μm, 120μm, 140μm, 160μm, 180μm or 200μm, etc.

[0061] For example, the thickness of the first passivation layer can be 15nm, 20nm, 25nm, 35nm, 40nm or 50nm, etc.

[0062] For example, the thickness of the doped layer can be 5 nm, 10 nm, 15 nm or 20 nm, etc.

[0063] For example, the thickness of the second conductive oxide layer can be 10 nm, 15 nm, 20 nm, 25 nm or 30 nm, etc.

[0064] For example, the thickness of the hole transport layer can be 1nm, 2nm, 3nm, 4nm or 5nm, etc.

[0065] For example, the thickness of the perovskite layer can be 500 nm, 600 nm, 700 nm, 900 nm or 1000 nm, etc.

[0066] For example, the thickness of the second passivation layer can be 10nm, 13nm, 15nm or 20nm, etc.

[0067] For example, the thickness of the electron transport layer can be 10nm, 15nm, 20nm, 25nm or 30nm, etc.

[0068] For example, the thickness of the buffer layer can be 5nm, 6nm, 7nm or 8nm, etc.

[0069] For example, the thickness of the protective layer can be 10nm, 12nm, 14nm, 16nm, 18nm or 20nm, etc.

[0070] For example, the thickness of the third conductive oxide layer can be 50nm, 60nm, 80nm, 100nm, 120nm or 150nm, etc.

[0071] For example, the thickness of the electrode can be 200nm, 250nm, 300nm or 350nm, etc.

[0072] This invention also provides a method for fabricating the above-mentioned perovskite / silicon tandem solar cell, comprising the following steps:

[0073] S1. A silicon substrate is provided, the silicon substrate having opposing first and second surfaces;

[0074] S2. A second conductive oxide layer is formed on the first surface of the silicon substrate;

[0075] S3. A nanoparticle layer is formed on the side of the second conductive oxide layer away from the silicon substrate.

[0076] S4. A first conductive oxide layer is formed on the side of the nanoparticle layer away from the silicon substrate.

[0077] S5. A hole transport layer is formed on the side of the first conductive oxide layer away from the silicon substrate.

[0078] S6. A perovskite layer is formed on the side of the hole transport layer away from the silicon substrate to obtain a perovskite / silicon tandem solar cell.

[0079] In some embodiments, the process of forming a nanoparticle layer on the side of the second conductive oxide layer away from the silicon substrate includes: forming a nanoparticle layer on the side of the second conductive oxide layer away from the silicon substrate using a first deposition process; preferably, the first deposition process includes one or more of sputtering, thermal evaporation, and sol-gel methods.

[0080] In some embodiments, the process of forming a second conductive oxide layer on a first surface of a silicon substrate includes: A1, forming a first passivation layer on the first surface of the silicon substrate; A2, forming a doped layer on the side of the first passivation layer opposite to the silicon substrate; A3, forming a second conductive oxide layer on the side of the doped layer opposite to the silicon substrate.

[0081] In some embodiments, when the nanoparticles comprise Al2O3 and / or ZnO, they can be prepared by spin coating, and the spacing between the nanoparticles can be controlled by adjusting the solution concentration. When the nanoparticles comprise SiO2, they are prepared by spray coating.

[0082] In some embodiments, the process of forming a first passivation layer on a first surface of a silicon substrate includes: using silane ( )and A first passivation layer is formed on the first surface of a silicon substrate using a third deposition process.

[0083] In some implementations, silane and The volume ratio is 1:(1-100).

[0084] In some implementations, the third deposition process includes plasma-enhanced chemical vapor deposition (PECVD).

[0085] In some embodiments, the process of forming a doped layer on the side of the first passivation layer away from the silicon substrate includes: forming a doped layer on the side of the first passivation layer away from the silicon substrate using B2H6 and silane gas through a fourth deposition process.

[0086] In some implementations, the volume ratio of B2H6 to silane is 1:(100-1000).

[0087] In some implementations, the fourth deposition process includes plasma-enhanced chemical vapor deposition (PECVD).

[0088] In some embodiments, the process of forming a second conductive oxide layer on the side of the doped layer away from the silicon substrate includes: forming a second conductive oxide layer on the side of the doped layer away from the silicon substrate using argon gas through a fifth deposition process.

[0089] In some implementations, the fifth deposition process includes plasma-enhanced chemical vapor deposition (PECVD).

[0090] In some embodiments, before forming the first passivation layer on the first surface of the silicon substrate, the method further includes the following steps: cleaning the silicon substrate with a solvent to remove organic impurities, particulate contaminants, and oil stains from the surface of the silicon substrate. Subsequently, the cleaned silicon substrate is subjected to plasma cleaning to obtain a clean silicon substrate.

[0091] In this embodiment of the invention, plasma cleaning refers to cleaning using high-energy plasma (such as Ar, etc.) under vacuum or normal pressure. Plasma is used to perform "microscopic cleaning and activation" on the surface of silicon substrates, solving problems such as tiny residues, surface oxide layers, and low activity that cannot be handled by solvent cleaning.

[0092] In some embodiments, the process of forming a first conductive oxide layer on the side of the nanoparticle layer away from the silicon substrate includes: forming the first conductive oxide layer on the side of the nanoparticle layer away from the silicon substrate using a second deposition process.

[0093] In some implementations, the second deposition process includes sputtering and / or atomic layer deposition.

[0094] In some embodiments, before the step of forming a hole transport layer on the side of the first conductive oxide layer away from the silicon substrate, the method further includes: plasma cleaning the first conductive oxide layer using plasma gas.

[0095] In some implementations, the plasma cleaning time is 5-10 minutes.

[0096] In some implementations, the plasma gas includes helium.

[0097] In some implementations, the plasma cleaning pressure is 30 Pa to 40 Pa.

[0098] In some embodiments, the process of forming a hole transport layer on the side of the first conductive oxide layer away from the silicon substrate includes: dissolving a hole transport material in a first solvent to obtain a first mixed solution; using a spin coater to spin coat the first mixed solution onto the surface of the first conductive oxide layer away from the silicon substrate to form a first wet film; and performing a first annealing treatment on the spin-coated sample to form a hole transport layer on the side of the first conductive oxide layer away from the silicon substrate.

[0099] In some embodiments, the hole transport material includes 4-methylphenyl-2-phenyl-5-phenyloxazole (Me-4PACz) and / or 4-methoxyphenyl-2-phenyl-5-phenyloxazole (MeO-2PACz).

[0100] In some implementations, the first solvent includes anhydrous ethanol.

[0101] In some embodiments, the concentration of the hole transport material in the first mixed solution is 0.3-1.5 mg / ml.

[0102] In some embodiments, the rotation speed of the first spin coat is 1000-5000 rpm, and the spin coat time is 20-40 s.

[0103] In some implementations, the temperature of the first annealing treatment is 50-150°C.

[0104] In some implementations, the first annealing process takes 5-15 minutes.

[0105] In some embodiments, the process of forming a perovskite layer on the side of the hole transport layer away from the silicon substrate includes: dissolving the perovskite material in a second solvent to obtain a second mixed solution; using a spin coater to spin coat the second mixed solution onto the side of the hole transport layer away from the silicon substrate to form a second wet film; and performing a second annealing treatment on the spin-coated sample to form a perovskite layer on the side of the hole transport layer away from the silicon substrate.

[0106] In some embodiments, the perovskite material includes Cs 0.05 (FA 0.77 MA 0.23 ) 0.95 Pb(I 0.77 Br 0.23 3.

[0107] In some embodiments, the second solvent includes one or more of N,N-dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone.

[0108] In some embodiments, the concentration of the hole transport material in the second mixed solution is 1-2M.

[0109] In some implementations, the temperature of the second annealing treatment is 50-150°C.

[0110] In some implementations, the second annealing process takes 10-40 minutes.

[0111] In some embodiments, the process of forming a second wet film on the side of the hole transport layer away from the silicon substrate by spin coating the second mixed solution includes: coating the second mixed solution on the side of the hole transport layer away from the silicon substrate, performing a third spin coating at 500-1500 rpm, and then performing a fourth spin coating at 2000-4000 rpm. When there are 15 seconds remaining before the end of the fourth spin coating, an anti-solvent is added to form a second wet film on the side of the hole transport layer away from the silicon substrate.

[0112] In some implementations, the third spin coating time is 5-15 seconds.

[0113] In some implementations, the fourth spin coating time is 25-40 seconds.

[0114] In some embodiments, the process of forming a perovskite layer on the side of the hole transport layer away from the silicon substrate to obtain a perovskite / silicon tandem solar cell further includes: B1, forming a perovskite layer on the side of the hole transport layer away from the silicon substrate; B2, forming a second passivation layer on the side of the perovskite layer away from the silicon substrate; B3, forming an electron transport layer on the side of the second passivation layer away from the silicon substrate; B4, forming a buffer layer on the side of the electron transport layer away from the silicon substrate; B5, forming a protective layer on the side of the buffer layer away from the silicon substrate; B6, forming a third conductive oxide layer on the side of the protective layer away from the silicon substrate; and B7, forming an electrode on the side of the third conductive oxide layer away from the silicon substrate to obtain a perovskite / silicon tandem solar cell.

[0115] In some embodiments, the process of forming a second passivation layer on the side of the perovskite layer away from the silicon substrate includes: dissolving an organic ammonium salt in a third solvent to obtain a third mixed solution, then coating the third mixed solution onto the side of the perovskite layer away from the silicon substrate, forming a third wet film of the third mixed solution on the side of the perovskite layer away from the silicon substrate by a fifth spin coating, and drying to form a second passivation layer on the side of the perovskite layer away from the silicon substrate.

[0116] In some embodiments, the concentration of the organic ammonium salt in the third mixed solution is 0.5-1.5 mg / mL.

[0117] In some embodiments, the third solvent includes isopropanol (IPA).

[0118] In some implementations, the rotation speed of the fifth spin coat is 3000-5000 rpm.

[0119] In some implementations, the fifth spin coating time is 20-40 seconds.

[0120] In some embodiments, the process of forming an electron transport layer on the side of the second passivation layer away from the silicon substrate includes: using a vacuum evaporation apparatus to form an electron transport layer on the side of the second passivation layer away from the silicon substrate by evaporation from an evaporation source.

[0121] In some implementations, the evaporation source includes fullerenes.

[0122] In some implementations, the evaporation temperature control rate is adjusted to 0.15-0.25 Å / s.

[0123] In some implementations, the thickness of the electron transport layer is 10-30 nm.

[0124] In some implementations, a vacuum evaporation device is used to reduce the vacuum level to <4×10⁻⁶. -4 Pa.

[0125] In some embodiments, the process of forming a buffer layer on the side of the electron transport layer away from the silicon substrate includes: dissolving a buffer material in a fourth solvent to obtain a fourth mixed solution, forming a fourth wet film on the side of the electron transport layer away from the silicon substrate by a sixth spin coating, and then forming a buffer layer on the side of the electron transport layer away from the silicon substrate by a third annealing.

[0126] In some embodiments, the buffer material comprises an organic aromatic heterocyclic compound, preferably comprising 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP).

[0127] In some embodiments, the fourth solvent includes isopropanol (IPA).

[0128] In some embodiments, the concentration of the buffer material in the fourth mixed solution is 0.1-1 mg / mL.

[0129] In some implementations, the spin coating speed for the sixth spin is 3000-5000 rpm, and the spin coating time for the sixth spin is 20-40 seconds.

[0130] In some implementations, the temperature of the third annealing treatment is 50-150°C.

[0131] In some implementations, the third annealing process takes 1-10 minutes.

[0132] In some implementations, the process of forming a protective layer on the side of the buffer layer away from the silicon substrate includes: using a sixth deposition process to form a protective layer on the side of the buffer layer away from the silicon substrate.

[0133] In some implementations, the sixth deposition process includes atomic layer deposition (ALD).

[0134] In some implementations, the thickness of the protective layer is 10-20 nm.

[0135] In some implementations, the tin source includes tetra(dimethylamino)tin (TDMASn).

[0136] In some embodiments, the process of forming a third conductive oxide layer on the side of the protective layer away from the silicon substrate includes sputtering the third conductive oxide layer on the side of the protective layer away from the silicon substrate at room temperature.

[0137] In some embodiments, the thickness of the third conductive oxide layer is 50-150 nm.

[0138] In some embodiments, the process of forming an electrode on the side of the third conductive oxide layer away from the silicon substrate to obtain a perovskite / silicon tandem solar cell includes: forming an electrode on the side of the third conductive oxide layer away from the silicon substrate using a vacuum evaporation method.

[0139] In some implementations, the thickness of the metal electrode is 200-350 nm.

[0140] The present invention will be further described below through specific embodiments.

[0141] Example 1

[0142] like Figure 1 As shown, the perovskite / silicon tandem solar cell of this embodiment includes a silicon substrate 14, a first passivation layer 1, a doped layer 2, a second conductive oxide layer 3, a nanoparticle layer 4, a first conductive oxide layer 5, a hole transport layer 6, a perovskite layer 7, a second passivation layer 8, an electron transport layer 9, a buffer layer 10, a protective layer 11, a third conductive oxide layer 12, and an electrode 13, which are stacked sequentially along a first direction (i.e., the direction indicated by the arrow X).

[0143] The fabrication method of perovskite / silicon tandem solar cells includes the following steps:

[0144] 1) Providing a silicon substrate: Clean the silicon substrate by using ethanol to remove impurities and dirt from the surface of the silicon substrate, followed by plasma cleaning to obtain a clean silicon substrate;

[0145] 2) First passivation layer: using H2 and Ar were deposited on the first surface of a silicon substrate using PECVD to obtain a first passivation layer at a temperature of 180°C. The volume ratio of H2 to SiH4 is 1:10, the volume ratio of SiH4 to Ar is 1:1, the deposition gas pressure is 100 Pa, and the power density is 100 mW / cm³. 2 The thickness of the first passivation layer is 8 nm;

[0146] 3) Doped layer: using B2H6 and silane ( A doped layer, B2H6, is formed by depositing a gas, B2H6, on the side of the first passivation layer away from the silicon substrate via PECVD. The volume ratio is 1:200, the PECVD deposition temperature is 180℃, the RF power is 30W, the cavity pressure is 200Pa, the growth rate of the doped layer is 0.5nm / s, and the thickness of the doped layer is 10nm.

[0147] 4) Second conductive oxide layer (ITO transparent conductive layer): The second conductive oxide layer is formed on the side of the doped layer away from the silicon substrate using O2 and Ar via PECVD. The RF power is 100W, and the working pressure of the reaction chamber is 6×10⁻⁶. -1 The volume ratio of Pa, O2 and Ar is 0.1:1;

[0148] 5) Nanoparticle layer: Prepared by spin coating. The spacing between nanoparticles can be controlled by adjusting the solution concentration. The average particle size of Al2O3 nanoparticles is 100 nm. They are dissolved in isopropanol at a concentration of 0.5 mg / ml. A nanoparticle layer is formed on the surface of the second conductive oxide layer away from the silicon substrate using spin coating (spin coating speed of 4000 rpm / min, spin coating time of 30 s). The spacing between two adjacent nanoparticles is 100 nm. The nanoparticles are stacked on the side away from the silicon substrate to form nano-sized protrusions with a height of 100 nm.

[0149] 6) First conductive oxide layer: The first conductive oxide layer (ITO) is deposited on the side of the nanoparticle layer away from the silicon substrate using an atomic layer deposition process with O2 and Ar. The thickness of the first conductive oxide layer is 4 nm. The conditions of the atomic layer deposition process are: 37 cycles, 2 minutes, and a growth rate of 1.1 Å / cycle.

[0150] 7) Surface treatment: He gas is used to perform plasma treatment on the surface of the first conductive oxide layer away from the nanoparticle layer for 5 minutes to introduce active functional groups such as hydroxyl and carboxyl groups to increase interfacial wettability.

[0151] 8) Hole transport layer (HTL layer): 4-methylphenyl-2-phenyl-5-phenyloxazole (Me-4PACz) and 4-methoxyphenyl-2-phenyl-5-phenyloxazole (MeO-2PACz) were dissolved in anhydrous ethanol at a mass ratio of 3:1 to prepare a mixed solution of 0.5 mg / ml. The mixed solution was then spin-coated onto the surface of the first conductive oxide layer away from the silicon substrate using a spin coater at a speed of 3000 rpm and a spin coating time of 30 s. After spin coating, the sample was subjected to a first annealing treatment at a temperature of 100℃ and a first annealing time of 10 min, thus forming an HTL layer on the side of the first conductive oxide layer away from the silicon substrate.

[0152] 9) Preparation of the perovskite layer: Cs with a concentration of 1.5 M was used... 0.05 (FA 0.77 MA 0.23 ) 0.95 Pb(I 0.77 Br 0.23 )3 The solution was dropped onto the surface of the HTL layer away from the silicon substrate. First, it was spin-coated at 500 rpm for 10 s, and then at 4000 rpm for 35 s. When there were 15 s left before the end of spin-coating, 150 μL of antisolvent (ethyl acetate) was added and a second annealing treatment was performed. The temperature of the second annealing treatment was 120 °C and the time of the second annealing treatment was 10 min. A perovskite layer was formed on the side of the HTL layer away from the silicon substrate.

[0153] 10) Second passivation layer: Phenethyl ammonium iodide (PEAI) is dissolved in isopropanol (IPA) to prepare a PEAI solution with a concentration of 0.5 mg / mL. Then, the PEAI solution is dropped onto the side of the perovskite layer away from the silicon substrate. Spin-coating is performed at 4000 rpm for 20 s. After drying, a second passivation layer is formed on the side of the perovskite layer away from the silicon substrate.

[0154] 11) Preparation of electron transport layer: using fullerene ( Using powder as the evaporation source, an electron transport layer was prepared on the side of the second passivation layer away from the silicon substrate using a vacuum evaporation device, with the vacuum level reduced to <4×10⁻⁶. -4 Pa, the evaporation temperature was adjusted to control the rate at 0.2 Å / s, and a 25 nm thick electron transport layer was deposited;

[0155] 12) Buffer layer: 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) was dissolved in isopropanol (IPA) to prepare a BCP solution with a concentration of 0.5 mg / mL. 80 μL of BCP solution was dynamically spin-coated at 4000 rpm for 30 s on the side of the electron transport layer away from the silicon substrate, and then annealed at 80 °C for 10 min to form a buffer layer on the side of the electron transport layer away from the silicon substrate.

[0156] 13) SnO x Protective layer: Using tetratetra(dimethylamino)tin (TDMASn) as the raw material, a 15nm thick SnO layer is deposited on the side of the buffer layer away from the silicon substrate using atomic layer deposition (ALD). x Protective layer;

[0157] 14) Third conductive oxide layer: fabricated using PECVD equipment, with an RF power of 100W and an operating voltage of 6×10⁻⁶. -1 The volume ratio of Pa, O2, and Ar is 0.1:1, and the mixture is prepared at room temperature in SnO. x A third conductive oxide layer with a thickness of 100 nm is sputtered on the side of the protective layer away from the silicon substrate;

[0158] 15) Electrode: A metal electrode (Ag) with a thickness of 250 nm is formed on the side of the third conductive oxide layer away from the silicon substrate by vacuum evaporation.

[0159] Example 2

[0160] The fabrication method of the perovskite / silicon tandem solar cell in this embodiment is basically the same as that in Example 1. The difference is that in step 5), during the preparation of the nanoparticle layer, a layer of SiO2 nanoparticles is deposited on the side of the second conductive oxide layer away from the silicon substrate using a spraying process. The average particle size of the SiO2 nanoparticles is 120 nm, and the spacing between two adjacent nanoparticles is 100 nm. The nanoparticles are stacked on the side of the second conductive oxide layer away from the silicon substrate to form nano-sized protrusions with a height of 120 nm. The remaining steps and conditions are the same as in Example 1.

[0161] Example 3

[0162] The fabrication method of the perovskite / silicon tandem solar cell in this embodiment is basically the same as that in Example 1. The difference is that in step 5), during the preparation of the nanoparticle layer, a ZnO nanoparticle layer is deposited on the side of the second conductive oxide layer away from the silicon substrate using a spin coating process. ZnO is dissolved in isopropanol at a concentration of 0.5 mg / ml. A nanoparticle layer is formed on the surface of the second conductive oxide layer away from the silicon substrate using a spin coating method (spin coating speed of 4000 rpm / min, spin coating time of 30 s). The average particle size of the ZnO nanoparticles is 120 nm, and the spacing between two adjacent nanoparticles is 100 nm. The nanoparticles are stacked on the side away from the silicon substrate to form nano-sized protrusions with a height of 120 nm. The remaining steps and conditions are the same as in Example 1.

[0163] Example 4

[0164] The fabrication method of the perovskite / silicon tandem solar cell in this embodiment is basically the same as that in Example 1, except that in step 5), during the preparation of the nanoparticle layer, a nanoparticle layer is deposited on the side of the second conductive oxide layer away from the silicon substrate using spin coating. Au nanoparticles with an average particle size of 100 nm are dispersed in ethanol to form a dispersion with a concentration of 0.5 mg / ml. The spin coating speed is 2000 rpm / min. After spin coating, annealing is performed at 100°C for 10 min. The spacing between two adjacent nanoparticles is 100 nm. The nanoparticles accumulate on the side away from the silicon substrate to form nanoscale protrusions with a height of 100 nm. The remaining steps and conditions are the same as in Example 1.

[0165] Example 5

[0166] The fabrication method of the perovskite / silicon tandem solar cell in this embodiment is basically the same as that in Example 1, except that in step 5), during the deposition of the nanoparticle layer, a nanoparticle layer is deposited on the side of the second conductive oxide layer away from the silicon substrate using spin coating. Ag nanoparticles with an average particle size of 100 nm are dispersed in ethanol to form a dispersion with a concentration of 5 mg / ml. The spin coating speed is 2000 rpm / min, and after spin coating, annealing is performed at a temperature of 200°C for 10 min. The spacing between two adjacent nanoparticles is 100 nm. The nanoparticles accumulate on the side away from the silicon substrate to form nanoscale protrusions with a height of 100 nm. The remaining steps and conditions are the same as in Example 1.

[0167] Example 6

[0168] The fabrication method of the perovskite / silicon tandem solar cell in this embodiment is basically the same as that in Example 1, except that in step 5), during the preparation of the nanoparticle layer deposition, a spraying method is used. An ethanol solution of copper salt (copper nitrate) is prepared (the concentration of copper salt in the dispersion is 0.1 mol / L), and a dispersant (polyvinylpyrrolidone, based on the concentration of the dispersion, is 0.5 mg / ml) is added and ultrasonically dispersed to obtain a dispersion. The dispersion is then sprayed onto the surface of the second conductive oxide layer away from the silicon substrate, followed by annealing at 200°C for 20 min in a nitrogen atmosphere. A Cu nanoparticle layer is deposited on the side of the second conductive oxide layer away from the silicon substrate. The average particle size of the nanoparticles is 120 nm, and the spacing between two adjacent nanoparticles is 100 nm. The nanoparticles accumulate on the side away from the silicon substrate to form nanoscale protrusions with a height of 120 nm. The remaining steps and conditions are the same as in Example 1.

[0169] Example 7

[0170] The fabrication method of the perovskite / silicon tandem solar cell in this embodiment is basically the same as that in Example 1. The difference is that in step 6), during the deposition of the first conductive oxide layer, an atomic layer deposition process is used to deposit the first conductive oxide layer (indium zinc oxide, IZO in this embodiment) on the side of the nanoparticle layer away from the silicon substrate. The thickness of the first conductive oxide layer is 4 nm. The conditions of the atomic layer deposition process are: 37 cycles, 2 minutes, and a growth rate of 1.1 Å / cycle. The remaining steps and conditions are the same as those in Example 1.

[0171] Example 8

[0172] The fabrication method of the perovskite / silicon tandem solar cell in this embodiment is basically the same as that in Example 1. The difference is that in step 6), during the deposition of the first conductive oxide layer, an atomic layer deposition process is used to deposit the first conductive oxide layer (aluminum-doped zinc oxide AZO in this embodiment) on the side of the nanoparticle layer away from the silicon substrate. The thickness of the first conductive oxide layer is 4 nm. The conditions of the atomic layer deposition process are: 37 cycles, 2 minutes, and a growth rate of 1.1 Å / cycle.

[0173] Example 9

[0174] The fabrication method of the perovskite / silicon tandem solar cell in this embodiment is basically the same as that in Example 1. The difference is that in step 6), during the deposition of the first conductive oxide layer, an atomic layer deposition process is used to deposit the first conductive oxide layer (IZO in this embodiment) on the side of the nanoparticle layer away from the silicon substrate. The thickness of the first conductive oxide layer is 30 nm. The conditions of the atomic layer deposition process are: 230 cycles, 10 minutes, and a growth rate of 1.3 Å / cycle.

[0175] Comparative Example 1

[0176] The fabrication method of the perovskite / silicon tandem solar cell in this comparative example is basically the same as that in Example 1, except that steps 5) and 6) are not performed, that is, the nanoparticle layer and the first conductive oxide layer are not sequentially stacked on the surface of the second conductive oxide layer. Specifically, the following steps are included:

[0177] 1) Providing a silicon substrate: Clean the silicon substrate by using ethanol to remove impurities and dirt from the surface of the silicon substrate, followed by plasma cleaning to obtain a clean silicon substrate;

[0178] 2) First passivation layer: using H2 and Ar were deposited on the first surface of a silicon substrate using PECVD to obtain a first passivation layer at a temperature of 180°C. The volume ratio of H2 to SiH4 is 1:10, the volume ratio of SiH4 to Ar is 1:1, and the deposition pressure is 100 Pa. The power density is 100 mW / cm³. 2 The thickness of the first passivation layer is 8 nm;

[0179] 3) Doped layer: using B2H6 and silane ( ) gas (B2H6 and The volume ratio of the two materials is 1:200. A doped layer is deposited on the side of the first passivation layer away from the silicon substrate by PECVD. The PECVD deposition temperature is 180℃, the RF power is 30W, the cavity pressure is 200Pa, the growth rate of the doped layer is 0.5nm / s, and the thickness of the doped layer is 10nm.

[0180] 4) Second conductive oxide layer (ITO transparent conductive layer): The second conductive oxide layer is formed on the side of the doped layer away from the silicon substrate using O2 and Ar via PECVD. The RF power is selected as 100W, and the operating voltage is 6×10⁻⁶. -1 The volume ratio of Pa, O2 and Ar is 0.1:1;

[0181] 5) Surface treatment: He gas is used to perform plasma treatment on the surface of the second conductive oxide layer away from the nanoparticle layer for 5 minutes to introduce active functional groups such as hydroxyl and carboxyl groups and increase the interfacial wettability.

[0182] 6) Hole transport layer (HTL layer): 4-methylphenyl-2-phenyl-5-phenyloxazole (Me-4PACz) and 4-methoxyphenyl-2-phenyl-5-phenyloxazole (MeO-2PACz) were dissolved in anhydrous ethanol at a mass ratio of 3:1 to prepare a mixed solution of 0.5 mg / ml. The mixed solution was then spin-coated onto the surface of the second conductive oxide layer away from the silicon substrate using a spin coater at a speed of 3000 rpm and a spin-coating time of 30 s. After spin-coating, the sample was subjected to a first annealing treatment at a temperature of 100℃ and a first annealing time of 10 min, thus forming an HTL layer on the side of the second conductive oxide layer away from the silicon substrate.

[0183] 7) Preparation of the perovskite layer: Cs with a concentration of 1.5 M was used... 0.05 (FA 0.77 MA 0.23 ) 0.95 Pb(I 0.77 Br 0.23)3 The solution was dropped onto the surface of the HTL layer away from the silicon substrate. First, it was spin-coated at 500 rpm for 10 s, and then at 4000 rpm for 35 s. When there were 15 s left before the end of spin-coating, 150 μL of antisolvent (ethyl acetate) was added and a second annealing treatment was performed. The temperature of the second annealing treatment was 120 °C and the time of the second annealing treatment was 10 min. A perovskite layer was formed on the side of the HTL layer away from the silicon substrate.

[0184] 8) Second passivation layer: Phenethyl ammonium iodide (PEAI) is dissolved in isopropanol (IPA) to prepare a PEAI solution with a concentration of 0.5 mg / mL. Then, the PEAI solution is dropped onto the side of the perovskite layer away from the silicon substrate. Spin-coating is performed at 4000 rpm for 20 seconds. After drying, a second passivation layer is formed on the side of the perovskite layer away from the silicon substrate.

[0185] 9) Preparation of electron transport layer: using fullerene ( Using powder as the evaporation source, an electron transport layer was prepared on the side of the second passivation layer away from the silicon substrate using a vacuum evaporation device, with the vacuum level reduced to <4×10⁻⁶. -4 Pa, the evaporation temperature was adjusted to control the rate at 0.2 Å / s, and an electron transport layer with a thickness of 25 nm was deposited;

[0186] 10) Buffer layer: Dissolve 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) in isopropanol (IPA) to prepare a BCP solution with a concentration of 0.5 mg / mL. Take 80 μL of BCP solution and spin-coat it dynamically at 4000 rpm for 30 s on the side of the electron transport layer away from the silicon substrate. Then anneal at 80 °C for 10 min to form a buffer layer on the side of the electron transport layer away from the silicon substrate.

[0187] 11) SnO x Protective layer: Using tetratetra(dimethylamino)tin (TDMASn) as the raw material, a 15nm thick SnO layer is deposited on the side of the buffer layer away from the silicon substrate using atomic layer deposition (ALD). x Protective layer;

[0188] 12) Third conductive oxide layer: fabricated using PECVD equipment, with an RF power of 100W and an operating voltage of 6×10⁻⁶. -1 The volume ratio of Pa, O2, and Ar is 0.1:1, and the mixture is prepared at room temperature in SnO. x A third conductive oxide layer with a thickness of 100 nm is sputtered on the side of the protective layer away from the silicon substrate;

[0189] 13) Electrode: The third conductive oxide layer is deposited using vacuum evaporation, away from SnO. x A 250nm metal electrode (Ag) is formed on one side of the protective layer.

[0190] Comparative Example 2

[0191] The fabrication method of this comparative perovskite / silicon tandem solar cell is basically the same as that of Example 1, except that step 6) was not performed, i.e., the first conductive oxide layer was not formed on the side of the nanoparticle layer facing away from the silicon substrate. Specifically, the following steps are included:

[0192] The fabrication method of perovskite / silicon tandem solar cells includes the following steps:

[0193] 1) Providing a silicon substrate: Clean the silicon substrate by using ethanol to remove impurities and dirt from the surface of the silicon substrate, followed by plasma cleaning to obtain a clean silicon substrate;

[0194] 2) First passivation layer: using H2 and Ar were deposited on the first surface of a silicon substrate using PECVD to obtain a first passivation layer at a temperature of 180°C. The volume ratio of H2 to SiH4 is 1:10, the volume ratio of SiH4 to Ar is 1:1, the deposition gas pressure is 100 Pa, and the power density is 100 mW / cm³. 2 The thickness of the first passivation layer is 8 nm;

[0195] 3) Doped layer: using B2H6 and silane ( ) gas (B2H6 and The volume ratio of the two materials is 1:200. A doped layer is deposited on the side of the first passivation layer away from the silicon substrate by PECVD. The PECVD deposition temperature is 180℃, the RF power is 30W, the cavity pressure is 200Pa, the growth rate of the doped layer is 0.5nm / s, and the thickness of the doped layer is 10nm.

[0196] 4) Second conductive oxide layer (ITO transparent conductive layer): The second conductive oxide layer is formed on the side of the doped layer away from the silicon substrate using O2 and Ar via PECVD. The RF power is selected as 100W, and the operating voltage is 6×10⁻⁶. -1 The volume ratio of Pa, O2 and Ar is 0.1:1;

[0197] 5) Nanoparticle layer: Prepared by spin coating. The spacing between nanoparticles can be controlled by adjusting the solution concentration. The average particle size of Al2O3 nanoparticles is 100 nm. They are dissolved in isopropanol at a concentration of 0.5 mg / ml. A nanoparticle layer is formed on the surface of the second conductive oxide layer away from the silicon substrate using spin coating (spin coating speed of 4000 rpm / min, spin coating time of 30 s). The spacing between two adjacent nanoparticles is 100 nm. The nanoparticles are stacked on the side away from the silicon substrate to form nano-sized protrusions with a height of 100 nm.

[0198] 6) Surface treatment: He gas is used to perform plasma treatment on the surface of the nanoparticle layer away from the silicon substrate for 5 minutes to introduce active functional groups such as hydroxyl and carboxyl groups to increase interfacial wettability;

[0199] 7) Hole transport layer (HTL layer): 4-methylphenyl-2-phenyl-5-phenyloxazole (Me-4PACz) and 4-methoxyphenyl-2-phenyl-5-phenyloxazole (MeO-2PACz) were dissolved in anhydrous ethanol at a mass ratio of 3:1 to prepare a mixed solution of 0.5 mg / ml. The mixed solution was spin-coated onto the surface of the nanoparticle layer away from the silicon substrate using a spin coater at a speed of 3000 rpm and a spin coating time of 30 s. After spin coating, the sample was subjected to a first annealing treatment at a temperature of 100℃ and a first annealing time of 10 min, forming an HTL layer on the side of the nanoparticle layer away from the silicon substrate.

[0200] 8) Preparation of the perovskite layer: Cs with a concentration of 1.5 M was used... 0.05 (FA 0.77 MA 0.23 ) 0.95 Pb(I 0.77 Br 0.23 )3 The solution was dropped onto the surface of the HTL layer away from the silicon substrate. First, it was spin-coated at 500 rpm for 10 s, and then at 4000 rpm for 35 s. When there were 15 s left before the end of spin-coating, 150 μL of antisolvent (ethyl acetate) was added and a second annealing treatment was performed. The temperature of the second annealing treatment was 120 °C and the time of the second annealing treatment was 10 min. A perovskite layer was formed on the side of the HTL layer away from the silicon substrate.

[0201] 9) Second passivation layer: Phenethyl ammonium iodide (PEAI) is dissolved in isopropanol (IPA) to prepare a PEAI solution with a concentration of 0.5 mg / mL. Then, the PEAI solution is dropped onto the side of the perovskite layer away from the silicon substrate. Spin-coating is performed at 4000 rpm for 20 s. After drying, a second passivation layer is formed on the side of the perovskite layer away from the silicon substrate.

[0202] 10) Preparation of electron transport layer: using fullerene ( Using powder as the evaporation source, an electron transport layer was prepared on the side of the second passivation layer away from the silicon substrate using a vacuum evaporation device, with the vacuum level reduced to <4×10⁻⁶. -4 Pa, the evaporation temperature was adjusted to control the rate at 0.2 Å / s, and a 25 nm thick electron transport layer was deposited;

[0203] 11) Buffer layer: Dissolve 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) in isopropanol (IPA) to prepare a BCP solution with a concentration of 0.5 mg / mL. Take 80 μL of BCP solution and spin-coat it dynamically at 4000 rpm for 30 s on the side of the electron transport layer away from the silicon substrate. Then anneal at 80 °C for 10 min to form a buffer layer on the side of the electron transport layer away from the silicon substrate.

[0204] 12) SnO x Protective layer: Using tetratetra(dimethylamino)tin (TDMASn) as the raw material, a 15nm thick SnO layer is deposited on the side of the buffer layer away from the silicon substrate using atomic layer deposition (ALD). x Protective layer;

[0205] 13) Third conductive oxide layer: fabricated using PECVD equipment, with an RF power of 100W and an operating voltage of 6×10⁻⁶. -1 The volume ratio of Pa, O2, and Ar is 0.1:1, and the mixture is prepared at room temperature in SnO. x A third conductive oxide layer with a thickness of 100 nm is sputtered on the side of the protective layer away from the silicon substrate;

[0206] 14) Electrode: The third conductive oxide layer is deposited using vacuum evaporation, away from SnO. x A 250nm metal electrode (Ag) is formed on one side of the protective layer.

[0207] The perovskite / silicon tandem solar cells in the above embodiments and comparative examples were subjected to JV (current-voltage) characteristic tests. The short-circuit current density, open-circuit voltage, fill factor, and photoelectric conversion efficiency of the perovskite / silicon tandem solar cells were measured. The JV (current-voltage) characteristic test conditions were ambient air (standard atmospheric pressure, temperature 20℃-30℃, relative humidity 40%±10%), and the illumination condition was AM1.5G (1 sun). The results are shown in Table 1 and [Table data missing]. Figure 2 .

[0208] like Figure 2 As shown, compared to Comparative Example 1, the perovskite / silicon tandem solar cell in Example 1 has a higher short-circuit current density and open-circuit voltage.

[0209] Table 1

[0210]

[0211] Analysis of Table 1 shows that, through a comparison of Examples 1-9 and Comparative Examples 1-2, the perovskite / silicon tandem solar cells in Examples 1-9 exhibit superior short-circuit current density, open-circuit voltage, fill factor, and photoelectric conversion efficiency. This indicates that in the perovskite / silicon tandem solar cell system of the present invention, the perovskite layer can be conformally covered on the silicon substrate, significantly improving the uniformity of the perovskite layer coverage; the hole transport layer can be uniformly adsorbed on the first conductive oxide layer, while the first conductive oxide layer provides a low-impedance transport channel for charge carriers, improving the carrier transport efficiency, thereby enhancing the short-circuit current density, open-circuit voltage, fill factor, and photoelectric conversion efficiency of the perovskite / silicon tandem solar cell.

[0212] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A perovskite / silicon tandem solar cell, characterized by, It includes a silicon substrate, a second conductive oxide layer, a nanoparticle layer, a first conductive oxide layer, a hole transport layer, and a perovskite layer, which are stacked sequentially along a first direction. The nanoparticle layer includes nanoparticles with a particle size range of 50-300 nm; the nanoparticle layer has nano-sized protrusions on the side opposite to the silicon substrate, the protrusions are formed by the accumulation of the nanoparticles, the height of the protrusions is 50-300 nm, and the spacing between two adjacent protrusions is 50-300 nm. The thickness of the second conductive oxide layer is greater than the thickness of the first conductive oxide layer. 2.The perovskite / silicon tandem solar cell of claim 1, wherein, The thickness of the first conductive oxide layer is x, where 0 < x ≤ 20 nm. 3.The perovskite / silicon tandem solar cell according to claim 1 or 2, characterized in that, The first conductive oxide layer includes one or more of indium tin oxide, indium zinc oxide, aluminum-doped zinc oxide, and indium gallium zinc oxide; And / or, the second conductive oxide layer comprises one or more of indium tin oxide, indium zinc oxide, aluminum-doped zinc oxide, and indium gallium zinc oxide.

4. The perovskite / silicon tandem solar cell according to any one of claims 1-3, characterized in that, The silicon substrate has a pyramidal textured surface with micron-sized edges on the side closest to the second conductive oxide layer; And / or, the nanoparticles include metallic nanoparticles and / or non-metallic nanoparticles.

5. The perovskite / silicon tandem solar cell according to claim 4, characterized in that, The metal nanoparticles include one or more of gold, silver, and copper; And / or, the non-metallic nanoparticles include one or more of aluminum oxide, zinc oxide, and silicon dioxide.

6. The perovskite / silicon tandem solar cell according to any one of claims 1-5, characterized in that, The perovskite / silicon tandem solar cell comprises, sequentially stacked along a first direction, a silicon substrate, a first passivation layer, a doped layer, a second conductive oxide layer, a nanoparticle layer, a first conductive oxide layer, a hole transport layer, a perovskite layer, a second passivation layer, an electron transport layer, a buffer layer, a protective layer, a third conductive oxide layer, and an electrode.

7. A method for fabricating a perovskite / silicon tandem solar cell according to any one of claims 1-6, characterized in that, Includes the following steps: S1. A silicon substrate is provided, the silicon substrate having opposing first and second surfaces; S2. A second conductive oxide layer is formed on the first surface of the silicon substrate; S3. A nanoparticle layer is formed on the side of the second conductive oxide layer opposite to the silicon substrate; S4. A first conductive oxide layer is formed on the side of the nanoparticle layer opposite to the silicon substrate; S5. A hole transport layer is formed on the side of the first conductive oxide layer opposite to the silicon substrate; S6. A perovskite layer is formed on the side of the hole transport layer away from the silicon substrate to obtain the perovskite / silicon tandem solar cell.

8. The preparation method according to claim 7, characterized in that, The process of forming a first conductive oxide layer on the side of the nanoparticle layer away from the silicon substrate includes: forming a first conductive oxide layer on the side of the nanoparticle layer away from the silicon substrate using an atomic layer deposition process.

9. The preparation method according to claim 7 or 8, characterized in that, Before the step of forming a hole transport layer on the side of the first conductive oxide layer away from the silicon substrate, the method further includes: performing plasma cleaning on the first conductive oxide layer using plasma gas.

10. The preparation method according to claim 9, characterized in that, The plasma cleaning time is 5-10 minutes; And / or, the plasma gas includes helium; And / or, the pressure of the plasma cleaning is 30Pa-40Pa.

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