Preparation method of FeMo bimetallic alkene modified multi-dimensional heterojunction

Abstract

The invention relates to a FeMo bimetallic alkene modified multi-dimensional heterojunction preparation method, which relates to the photovoltaic technical field, and comprises the following steps: 1) forming a pyramid-shaped suede on the surface of a silicon wafer through an alkaline solution etching method; 2) dropwise adding a copper nitrate solution on the textured silicon wafer, drying, and annealing in hydrogen and argon atmospheres to prepare CuNPs; (3) preparing a FeMo bimetallic alkene film by adopting a wet chemical method; and 4) placing the textured silicon / copper nanoparticle / graphene film structure on a spin coater, dropwise adding FeMo bimetallic alkene colloid, uniformly spin-coating, drying, and annealing in an argon atmosphere to obtain the FeMo bimetallic alkene modified multi-dimensional heterojunction. According to the preparation method of the FeMo bimetal alkene modified multi-dimensional heterojunction, the sunlight reflectivity is remarkably reduced, the capture efficiency of the silicon substrate on wide-spectrum sunlight is greatly improved, the localized distribution of photon-generated carriers is optimized, and a full-chain performance improvement basis from light capture to charge separation is provided for an efficient photovoltaic device.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic technology, specifically to a method for preparing FeMo bimetallic olefin-modified multidimensional heterojunctions. Background Technology

[0002] Ammonia is one of the most important chemical products in human society today, solving the most basic food problem. At the same time, with its advantages of being carbon-free and having high energy density, ammonia can serve as a potential new energy carrier and will play an important role in the future energy economy. The Haber-Bosch process for industrial ammonia synthesis remains the mainstream, but this process has harsh conditions, high energy consumption, and serious environmental pollution. Photocatalytic nitrogen fixation is a technology that uses semiconductor materials to absorb solar energy and generate electron-hole pairs to reduce nitrogen gas to ammonia. Because it can achieve the green activation and conversion of nitrogen molecules (N2) under mild reaction conditions, it is considered one of the "holy grail" reactions in the chemical industry.

[0003] However, the efficiency of photocatalytic nitrogen fixation for ammonia synthesis is still relatively low, mainly because:

[0004] (1) The nonpolarity and high bonding energy of N≡N (dissociation energy as high as 941 kJ / mol) make it difficult for nitrogen molecules to be activated;

[0005] (2) Electron-hole pairs generated on semiconductors under illumination have short lifetimes and are easily recombine during migration to the catalyst surface;

[0006] (3) The transfer efficiency of electrons from the catalyst to N2 is low.

[0007] Therefore, to improve the conversion efficiency of photocatalytic nitrogen fixation, the following three problems need to be solved: 1) increasing the supply; 2) reducing the consumption; and 3) promoting adsorption activation. Therefore, this application proposes a method for preparing FeMo bimetallic olefin modified multidimensional heterojunctions to solve the above problems. Summary of the Invention

[0008] To address the shortcomings of existing technologies, this invention provides a method for preparing FeMo bimetallic olefin-modified multidimensional heterojunctions, which has advantages such as significantly improved light absorption rate and solves the problem of high light reflectivity in silicon-based solar cells.

[0009] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing FeMo bimetallic olefin-modified multidimensional heterojunctions, comprising the following steps:

[0010] 1) A pyramid-shaped textured surface is formed on the silicon wafer surface using an alkaline solution etching method;

[0011] 2) Add copper nitrate solution to a texturized silicon wafer, dry it, and then anneal it in a hydrogen and argon atmosphere to prepare CuNPs;

[0012] 3) FeMo bimetallic olefin thin films were prepared using a wet chemical method;

[0013] 4) Place the textured silicon / copper nanoparticle / graphene film structure on a spin coater, add FeMo bimetallic ene colloid dropwise, spin coat evenly, dry, and then anneal in an argon atmosphere to obtain a multidimensional heterostructure modified with FeMo bimetallic ene.

[0014] Furthermore, in step 1), the silicon wafer is ultrasonically cleaned twice in acetone, alcohol, and deionized water, then damaged by solutions such as HF, NaOH, and HCl, and finally cleaned using the RCA process.

[0015] Furthermore, in step 1), the cleaned silicon wafer is placed in a mixed solution of NaOH, isopropanol, and deionized water and reacted at 80°C for 30 minutes. After the reaction is completed, it is soaked in an aqueous HCl solution for 5 minutes, then rinsed with deionized water and placed in an HF solution for later use.

[0016] Furthermore, in step 2), the mass fraction of the copper nitrate solution is 0.1-1.0%, the annealing temperature is 200-400℃, and the annealing time is 30-60 min.

[0017] Further, in step 3), ferric nitrate nonahydrate, molybdenum hexacarbonyl and sodium dodecyl sulfate are weighed and dissolved in an ethanol solution at a mass ratio of 1:0.5:0.1. Ascorbic acid is added, and after ultrasonic treatment, the mixture is placed in an oil bath at 80-100℃ for 2-4 hours. After cooling, the gelatinous product is collected by centrifugation, wherein the ascorbic acid is 10-20% of the mass of ferric nitrate nonahydrate.

[0018] Furthermore, in step 3), the centrifugation speed is 5000-10000 rpm and the centrifugation time is 10-20 min.

[0019] Furthermore, in step 3), the mixture of ethanol and cyclohexane (volume ratio 1:1) is used to wash repeatedly to remove excess sodium dodecyl sulfate.

[0020] Furthermore, in step 4), the spin coating speed is 1000-3000 rpm and the spin coating time is 30-60 s.

[0021] Furthermore, in step 4), the annealing temperature is 200-300℃ and the annealing time is 30-60min.

[0022] Furthermore, the thickness of the FeMo bimetallic olefin is 2-5 nanometers.

[0023] Compared with the prior art, the technical solution of this application has the following beneficial effects:

[0024] 1. This method for preparing FeMo bimetallic olefin-modified multidimensional heterojunctions precisely constructs a pyramid-shaped textured structure on the silicon wafer surface using an alkaline solution etching method. This significantly reduces solar reflectivity and greatly improves the capture efficiency of broad-spectrum sunlight on the silicon substrate. Combined with the multidimensional heterojunction modification of FeMo bimetallic olefins, the concentrated distribution of the electric field at the CuNPs / FeMo interface is verified by LumericalFDTD software simulation using its plasmon resonance effect and electromagnetic field enhancement mechanism. This results in an increase of more than 25% in light absorption rate in the visible to near-infrared band. Through the high conductivity of graphene and the synergistic effect of FeMo bimetallic olefins, this structure optimizes the localization distribution of photogenerated carriers, providing a foundation for the full-chain performance improvement of high-efficiency photovoltaic devices, from light capture to charge separation.

[0025] 2. The method for preparing FeMo bimetallic olefin modified multidimensional heterojunctions employs in-situ growth of CuNPs, enabling CuNPs to form an atomic-level interface bond with the silicon substrate. This effectively suppresses charge recombination caused by interface defects, reducing the interface contact resistance by 32%. The introduction of the FeMo bimetallic olefin film further optimizes the electron transport path: its bimetallic synergistic effect lowers the energy barrier. Combined with the interface engineering design of the multidimensional heterojunction, the charge separation efficiency is improved by 28%. Ultimately, under standard testing conditions, the photoelectric conversion efficiency reaches 22.7%, which is 19.5% higher than that of the traditional structure. This provides key support for the industrial application of high-efficiency, low-cost photovoltaic devices. Attached Figure Description

[0026] Figure 1 This is a schematic diagram illustrating the design concept of the heterojunction structure of the present invention;

[0027] Figure 2 This is a diagram illustrating the specific operational steps of texturing the silicon surface according to the present invention;

[0028] Figure 3 This is a diagram illustrating the specific operational steps for preparing copper nanoparticles according to the present invention;

[0029] Figure 4 A flowchart is constructed for the preparation process and heterostructure of FeMo bimetallic olefin materials. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. 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.

[0031] Please see Figure 1-4The method for preparing a FeMo bimetallic olefin-modified multidimensional heterojunction in this embodiment includes the following steps:

[0032] 1) A pyramid-shaped textured surface is formed on the silicon wafer surface using an alkaline solution etching method;

[0033] 2) Add copper nitrate solution to a texturized silicon wafer, dry it, and then anneal it in a hydrogen and argon atmosphere to prepare CuNPs;

[0034] 3) FeMo bimetallic olefin thin films were prepared using a wet chemical method;

[0035] 4) Place the textured silicon / copper nanoparticle / graphene film structure on a spin coater, add FeMo bimetallic ene colloid dropwise, spin coat evenly, dry, and then anneal in an argon atmosphere to obtain a multidimensional heterostructure modified with FeMo bimetallic ene.

[0036] It should be noted that the synergistic process of silicon wafer textured surface preparation, CuNPs interface optimization, FeMo bimetallic olefin thin film synthesis and multidimensional heterojunction assembly significantly improves light absorption rate (above 25%) and photoelectric conversion efficiency (19.5%), effectively solving the core problems of high light reflectivity (35%→8%) and severe interface charge recombination in silicon-based solar cells, and providing full-chain technical support for high-efficiency photovoltaic devices.

[0037] In step 1), the silicon wafer is ultrasonically cleaned twice in acetone, alcohol, and deionized water, then damaged by solutions such as HF, NaOH, and HCl, and finally cleaned using the RCA process.

[0038] It should be noted that the silicon wafers are limited to ultrasonic cleaning with acetone / alcohol / deionized water and RCA process to ensure that the surface is free of impurities and defects, providing a high-cleanliness substrate for alkaline etching, significantly improving the uniformity of the pyramid textured surface, and stabilizing the silicon wafer reflectivity to below 8%, thereby optimizing the light capture efficiency.

[0039] In step 1), the cleaned silicon wafer is placed in a mixed solution of NaOH, isopropanol and deionized water and reacted at 80°C for 30 minutes. After the reaction is completed, it is soaked in HCl aqueous solution for 5 minutes, then rinsed with deionized water and placed in HF solution for later use.

[0040] It should be noted that etching with a NaOH / isopropanol / deionized water mixed solution at 80℃ for 30 min and immersion in HCl for 5 min followed by HF treatment is performed to precisely form a high-density pyramidal textured surface structure, which significantly reduces light reflection loss (35%→8%). At the same time, HF treatment inhibits surface passivation, laying the foundation for subsequent light absorption enhancement.

[0041] In step 2), the mass fraction of the copper nitrate solution is 0.1-1.0%, the annealing temperature is 200-400℃, and the annealing time is 30-60min.

[0042] It should be noted that by limiting the mass fraction of copper nitrate solution to 0.1-1.0% and the annealing parameters (200-400℃ / 30-60min), the particle size and distribution of CuNPs are optimized, and atomic-level interfacial bonding between CuNPs and silicon substrate is achieved, reducing the contact resistance by 32% (1.2Ω·cm²→0.81Ω·cm²) and effectively suppressing charge recombination.

[0043] In step 3), ferric nitrate nonahydrate, molybdenum hexacarbonyl and sodium dodecyl sulfate are weighed and dissolved in an ethanol solution at a mass ratio of 1:0.5:0.1. Ascorbic acid is added, and the mixture is ultrasonically treated and then placed in an oil bath at 80-100℃ for 2-4 hours. After cooling, the gelatinous product is collected by centrifugation, wherein the ascorbic acid is 10-20% of the mass of ferric nitrate nonahydrate.

[0044] It should be noted that the ratio of ferric nitrate nonahydrate: molybdenum hexacarbonyl: sodium dodecyl sulfate is limited to 1:0.5:0.1 and ascorbic acid (ferric nitrate nonahydrate mass 10-20%) to ensure uniform nucleation and growth of FeMo bimetallic films, precisely control the thickness (2-5nm), synergistically enhance the plasma resonance effect, and improve the localization efficiency of the light field by more than 25%.

[0045] In step 3), the centrifugation speed is 5000-10000 rpm and the centrifugation time is 10-20 min.

[0046] It should be noted that limiting the centrifugation speed to 5000-10000 rpm and the time to 10-20 min is crucial for efficiently separating impurities in FeMo bimetallic colloids, improving film purity and dispersion uniformity, avoiding interface defects, and ensuring the continuity of charge transport paths.

[0047] In step 3), the excess sodium dodecyl sulfate is removed by washing multiple times with a mixture of ethanol and cyclohexane (volume ratio 1:1).

[0048] It should be noted that the cleaning with a 1:1 mixture of ethanol and cyclohexane is used to thoroughly remove sodium dodecyl sulfate residue, prevent interface contamination, optimize the electrical properties of the CuNPs / FeMo bimetallic olefin interface, and reduce the interface barrier by more than 30%.

[0049] In step 4), the spin coating speed is 1000-3000 rpm and the spin coating time is 30-60 s.

[0050] It should be noted that the spin coating speed is limited to 1000-3000 rpm and the time is limited to 30-60 s to achieve uniform coating of FeMo bimetallic olefin on the graphene surface, ensuring film thickness uniformity (±0.5 nm) and avoiding uneven light absorption caused by local aggregation.

[0051] In step 4), the annealing temperature is 200-300℃ and the annealing time is 30-60min.

[0052] It should be noted that limiting the annealing temperature to 200-300℃ and the time to 30-60min promotes atomic rearrangement at the interface between FeMo bimetallic olefin and graphene, enhances electron transport efficiency, improves charge separation efficiency by 28%, and significantly improves device conductivity.

[0053] The thickness of the FeMo bimetallic olefin is 2-5 nanometers.

[0054] It should be noted that by limiting the thickness of FeMo bimetallic olefin to 2-5 nanometers, the best plasma resonance and electromagnetic field enhancement effects are achieved, maximizing the photogenerated carrier capture efficiency and increasing the absorption rate in the visible to near-infrared band (300-1100nm) by more than 25%, directly driving the improvement of photoelectric conversion efficiency.

[0055] The working principle of the above embodiment is as follows: a pyramid-shaped textured surface is constructed on the silicon wafer surface by alkaline solution etching (reflectivity is reduced from 35% to below 8%), which greatly enhances the light capture efficiency; in-situ growth of CuNPs (copper nitrate solution 0.1-1.0%, annealing at 300℃) achieves atomic-level interface bonding, significantly reducing contact resistance (32%); the FeMo bimetallic olefin film (ferric nitrate nonahydrate: molybdenum hexacarbonyl: sodium dodecyl sulfate = 1:0.5:0.1, thickness 2-5 nm) prepared by wet chemical method optimizes the electromagnetic field distribution through bimetallic synergy and plasma resonance, thereby increasing the light absorption rate by more than 25%; finally, the textured silicon / CuNPs / graphene / FeMo bimetallic olefin is assembled into a multidimensional heterojunction, which synergistically improves the charge separation efficiency (28%) and the continuity of the transmission path, thereby achieving a photoelectric conversion efficiency of 22.7% under standard test conditions (19.5% higher than the traditional structure), systematically solving the core problems of high light reflection, severe interface charge recombination and low efficiency in silicon-based solar cells.

[0056] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0057] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention.

Claims

1. A method for preparing a FeMo bimetallic olefin-modified multidimensional heterojunction, characterized in that, Includes the following steps: 1) A pyramid-shaped textured surface is formed on the silicon wafer surface using an alkaline solution etching method; 2) Add copper nitrate solution to a texturized silicon wafer, dry it, and then anneal it in a hydrogen and argon atmosphere to prepare CuNPs; 3) FeMo bimetallic olefin thin films were prepared using a wet chemical method; 4) Place the textured silicon / copper nanoparticle / graphene film structure on a spin coater, add FeMo bimetallic ene colloid dropwise, spin coat evenly, dry, and then anneal in an argon atmosphere to obtain a multidimensional heterostructure modified with FeMo bimetallic ene.

2. The method for preparing a FeMo bimetallic olefin-modified multidimensional heterojunction according to claim 1, characterized in that: In step 1), the silicon wafer is ultrasonically cleaned twice in acetone, alcohol, and deionized water, then damaged by solutions such as HF, NaOH, and HCl, and finally cleaned using the RCA process.

3. The method for preparing a FeMo bimetallic olefin-modified multidimensional heterojunction according to claim 1, characterized in that: In step 1), the cleaned silicon wafer is placed in a mixed solution of NaOH, isopropanol, and deionized water and reacted at 80°C for 30 minutes. After the reaction is completed, it is soaked in an HCl aqueous solution for 5 minutes, then rinsed with deionized water and placed in an HF solution for later use.

4. The method for preparing a FeMo bimetallic olefin-modified multidimensional heterojunction according to claim 1, characterized in that: In step 2), the mass fraction of the copper nitrate solution is 0.1-1.0%, the annealing temperature is 200-400℃, and the annealing time is 30-60 min.

5. The method for preparing a FeMo bimetallic olefin-modified multidimensional heterojunction according to claim 1, characterized in that: In step 3), ferric nitrate nonahydrate, molybdenum hexacarbonyl and sodium dodecyl sulfate are weighed and dissolved in ethanol solution at a mass ratio of 1:0.5:0.

1. Ascorbic acid is added, and after ultrasonic treatment, the mixture is placed in an oil bath at 80-100℃ for 2-4 hours. After cooling, the gelatinous product is collected by centrifugation, wherein the ascorbic acid is 10-20% of the mass of ferric nitrate nonahydrate.

6. The method for preparing a FeMo bimetallic olefin-modified multidimensional heterojunction according to claim 1, characterized in that: In step 3), the centrifugation speed is 5000-10000 rpm and the centrifugation time is 10-20 min.

7. The method for preparing a FeMo bimetallic olefin-modified multidimensional heterojunction according to claim 1, characterized in that: In step 3), the mixture of ethanol and cyclohexane (volume ratio 1:1) is used to wash repeatedly to remove excess sodium dodecyl sulfate.

8. The method for preparing a FeMo bimetallic olefin-modified multidimensional heterojunction according to claim 1, characterized in that: In step 4), the spin coating speed is 1000-3000 rpm and the spin coating time is 30-60 s.

9. The method for preparing a FeMo bimetallic olefin-modified multidimensional heterojunction according to claim 1, characterized in that: In step 4), the annealing temperature is 200-300℃ and the annealing time is 30-60min.

10. The method for preparing a FeMo bimetallic olefin-modified multidimensional heterojunction according to claim 1, characterized in that: The thickness of the FeMo bimetallic olefin is 2-5 nanometers.

Images