High-efficiency silicon-based water-volte device and preparation method thereof
By introducing a hole-selective transport layer into a silicon nanostructured water-voltaic device, the problems of interface recombination loss and contact resistance are solved, the charge collection efficiency and output power are improved, and efficient charge transport and collection are realized, which can be applied to drive diode lamp arrays.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SUZHOU UNIV
- Filing Date
- 2022-10-31
- Publication Date
- 2026-05-19
AI Technical Summary
Existing silicon nanostructured water-voltaic devices suffer from severe interfacial recombination losses during charge transport and collection, resulting in insufficient output power and high contact resistance, which affects charge collection efficiency.
A hole-selective transport layer is introduced between the positive electrode and the silicon nanostructure. A built-in electric field is formed using a high work function material to prevent electron migration and promote hole transport. The surface contact increases the contact area and reduces interfacial recombination loss.
It significantly improves the efficiency of charge separation and collection, enhances the output power density of silicon-based water-voltaic devices, realizes efficient charge transport and collection, and the fabricated devices can drive multiple diode lamp arrays.
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Figure CN115765522B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of water-based photovoltaic devices, specifically to a high-efficiency silicon-based water-based photovoltaic device and its fabrication method. Background Technology
[0002] The evaporation-driven photovoltaic effect is an emerging technology that generates electricity through the direct interaction between nanomaterials and various forms of water (raindrops, waves, flow, and natural evaporation). This spontaneous and ubiquitous process directly converts thermal energy from the surrounding environment into electrical energy without requiring additional mechanical work, demonstrating unique advantages compared to other effects and thus holding broad application prospects in the field of new energy conversion. In recent years, evaporation-driven photovoltaic technology has received widespread attention and research, with ongoing studies leading to its application in self-powered systems and low-power devices. However, its poor output power and energy conversion efficiency still limit its use in other areas.
[0003] Among them, silicon nanostructure-based water-voltaic devices possess advantages such as large charged specific surface area, excellent charge carrier transport characteristics, and regularly oriented nanochannel structures, enabling them to continuously output power densities three orders of magnitude higher than similar devices. Therefore, they have potential advantages in constructing water-voltaic devices. Currently, the structure of silicon nanowire array water-voltaic devices mainly consists of a positive electrode / silicon nanowire array / negative electrode. Their output power is fundamentally determined by two factors: one is the charge generation process, which depends on the interaction between silicon nanostructures and water molecules. This is usually achieved by changing the hydrophilicity and zeta potential of the material to enhance capillary force and water evaporation rate, thereby accelerating water flow in the nanochannels and thus increasing output power. The other factor is the charge transport and collection process, which depends on the interface characteristics of the device. However, most current research focuses on active materials that directly interact with water, with less attention paid to charge transfer at the cross-section between the electrode and the active material. Summary of the Invention
[0004] The technical problem to be solved by this invention is to provide a high-efficiency silicon-based photovoltaic device and its fabrication method. By introducing a hole-selective transport layer at the silicon nanostructure / positive electrode interface, the internal electric field formed by the high work function hole-selective transport layer at the interface prevents electrons from migrating to the positive electrode, thereby achieving selective hole transport, reducing interface recombination losses, and improving charge separation and collection efficiency. At the same time, the introduced hole-selective transport layer transforms the point contact between the silicon nanostructure and the positive electrode into a surface contact, reducing the contact resistance at the positive electrode interface and further promoting efficient hole transport at the interface, thereby increasing the electrode's hole collection efficiency. Under the above synergistic effect, the electrical performance of the silicon-based photovoltaic device is effectively improved.
[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution:
[0006] The first aspect of the present invention provides a high-efficiency silicon-based water-voltaic device, which is composed of a positive electrode, a hole-selective transport layer, a silicon nanostructure, a silicon substrate, and a negative electrode in sequence from top to bottom. The top part of the silicon nanostructure is embedded in the hole-selective transport layer. The hole-selective transport layer is made of one or more of cobalt oxide, tungsten oxide, vanadium oxide, and nickel oxide.
[0007] Furthermore, the positive electrode is a carbon nanotube fabric electrode, a graphite fabric electrode, a grid electrode, a gold grid electrode, or a graphite / PEDOT:PSS / fabric electrode.
[0008] Furthermore, the material of the hole-selective transport layer is cobalt oxide and / or nickel oxide.
[0009] When protons continuously flow downwards within silicon nanochannels, the Coulomb attraction induces electrons to migrate downwards within the silicon nanostructure, creating a potential difference between the upper and lower ends of the structure. In existing positive / silicon nanowire array / negative electrode structures, the silicon nanowire array is in direct contact with the positive electrode, causing electrons to migrate from the nanowires to the electrode, resulting in severe electron-hole recombination at the interface. This affects the hole collection efficiency of the positive electrode and consequently, the output power. To address this issue, this invention introduces a hole-selective transport layer with a high work function between the positive electrode and the silicon nanostructure. This generates an enhanced built-in electric field at the silicon nanowire / hole-selective transport layer interface, inducing a significant upward bending of the silicon nanowire bands. This prevents electrons from drifting towards the positive electrode, thereby promoting selective hole transport, significantly suppressing electron-hole recombination, and enhancing the hole collection efficiency of the positive electrode.
[0010] Furthermore, in existing positive electrode / silicon nanowire array / negative electrode structures, when the silicon nanowire array is in direct contact with the positive electrode, the contact is point-to-point with a small contact area. This leads to hole accumulation at the tips of the silicon nanowires, preventing effective transport to and collection of holes at the positive electrode. Consequently, severe electron-hole recombination occurs at the interface, resulting in low charge transport and collection efficiency. In contrast, the high-efficiency silicon-based water-voltaic device fabricated in this invention embeds the top portion of the silicon nanostructure into the hole-selective transport layer. This hole-selective transport layer forms a surface contact with the top of the silicon nanostructure, significantly increasing the contact area and facilitating hole transport to the positive electrode, thereby significantly enhancing hole transport and collection efficiency at the interface.
[0011] Furthermore, the thickness of the hole-selective transport layer is 50–800 nm.
[0012] Furthermore, the thickness of the hole-selective transport layer is preferably 100–500 nm.
[0013] The thickness of the hole selective transport layer should not be too thick. An excessively thick hole selective transport layer has a large resistance, which reduces the hole transport rate. Moreover, it reduces the porosity of the silicon nanowire array, hindering the penetration and evaporation of water, which in turn reduces the output power of the water-voltaic device.
[0014] Furthermore, the silicon nanostructure is a silicon nanowire, silicon nanopore, silicon nanocone, silicon nanopillar, or silicon pyramid.
[0015] Furthermore, the high-efficiency silicon-based water-voltaic device also includes an electron-selective transport layer disposed between the silicon substrate and the negative electrode; the material of the electron-selective transport layer is one or more of magnesium oxide, titanium oxide, niobium oxide, barium oxide, tin oxide, and tantalum oxide.
[0016] Furthermore, the negative electrode is a gold electrode, a silver electrode, or an aluminum electrode.
[0017] A second aspect of the present invention provides a method for fabricating the aforementioned high-efficiency silicon-based water-voltaic device, comprising the following steps:
[0018] (1) The surface of the silicon wafer is treated to remove organic matter and oxides from the surface of the silicon wafer to obtain the treated silicon wafer;
[0019] (2) The silicon wafer processed in step (1) is used to prepare silicon nanostructures by metal-assisted chemical etching or photolithography;
[0020] (3) Place the silicon nanostructure prepared in step (2) in dilute nitric acid and let it stand for 5 to 10 minutes to remove the unreacted silver particles. Then rinse with ultrapure water to remove impurities and obtain the pretreated silicon nanostructure.
[0021] (4) Dissolve the hole selective transport layer precursor in water to obtain a hole selective transport layer precursor solution, and spin-coat, drop-coat or inkjet print it onto the surface of the pretreated silicon nanostructure. After annealing, place it under ultraviolet ozone for oxidation treatment to form the hole selective transport layer on top of the silicon nanostructure. The top part of the silicon nanostructure is embedded with the hole selective transport layer.
[0022] Furthermore, the preparation method also includes preparing an electron selective transport layer on the surface of a silicon substrate by methods such as spin coating, spray coating, blade coating, inkjet printing or vacuum thermal evaporation.
[0023] Furthermore, the preparation method also includes preparing a negative electrode on the surface of the electron selective transport layer by methods such as spin coating, spray coating, blade coating, inkjet printing or vacuum thermal evaporation.
[0024] Furthermore, the preparation method also includes preparing a positive electrode on the surface of the hole selective transport layer by methods such as spin coating, spraying, scraping, inkjet printing, vacuum thermal evaporation, or adhesion.
[0025] Furthermore, the hole-selective transport layer precursor solution is cobalt acetate tetrahydrate; the concentration of the hole-selective transport layer precursor solution is 3–8 mg·mL. -1 .
[0026] The beneficial effects of this invention are as follows:
[0027] 1. This invention provides a high-efficiency silicon-based photovoltaic device, comprising a hole-selective transport layer disposed between a positive electrode and a silicon nanostructure. The hole-selective transport layer partially penetrates into the silicon nanostructure, forming a surface contact with it, effectively reducing the contact resistance at the positive electrode interface, promoting efficient hole transport at the interface, and thus improving the hole collection efficiency of the positive electrode. Furthermore, this application introduces a high work function hole-selective transport layer between the positive electrode and the silicon nanostructure, forming a built-in electric field at the interface, which effectively prevents electron migration to the positive electrode, thereby achieving selective hole transport, effectively reducing interface recombination losses, and thus improving charge separation and collection. Under the synergistic effect of reducing interface contact resistance and reducing interface recombination losses, the output power of the silicon-based photovoltaic device is effectively improved.
[0028] 2. The high-efficiency silicon-based photovoltaic device of the present invention has a simple fabrication process and low cost. When the introduced hole-selective transport layer is cobalt oxide, the fabricated silicon-based photovoltaic device can continuously generate an open-circuit voltage of 0.82V and a current of 36.0μA·cm⁻¹. -2 The short-circuit current density and the peak output power density under a 10KΩ load are 17.0 μW·cm². -2 The four tandem silicon nanowire arrays of the water-voltaic device successfully drove an array of 25 red, white, green, and purple diode bulbs, demonstrating excellent electrical performance. Attached Figure Description
[0029] Figure 1 This is a schematic diagram of the structure of a high-efficiency silicon-based water-voltaic device;
[0030] Figure 2 A schematic diagram of the process of preparing a cobalt oxide thin film on the top of a silicon nanowire array;
[0031] Figure 3 Scanning electron microscope (SEM) images of the side (a) and top (b) surfaces of a silicon nanowire array based on a cobalt oxide interface layer;
[0032] Figure 4 Scanning electron microscope (SEM) images of the side surface and different positions of a silicon nanowire array based on a cobalt oxide interface layer;
[0033] Figure 5 This is a schematic diagram of the cross-sectional structure of silicon nanowires and cobalt oxide, where 1 is the positive electrode, 2 is cobalt oxide, and 3 is silicon nanowires.
[0034] Figure 6 Electrical performance of silicon-based water-voltaic devices prepared in Examples 1-3 and Comparative Examples 1-2: (a) curves showing the change of open-circuit voltage over time for different silicon-based water-voltaic devices; (b) curves showing the change of short-circuit current density over time for different silicon-based water-voltaic devices.
[0035] Figure 7 The peak power density of the silicon-based water-voltaic devices prepared in Examples 1-3 and Comparative Examples 1-2 under a 10KΩ load;
[0036] Figure 8 Scanning electron microscopy images of silicon nanowire arrays at different cobalt oxide concentrations: 3 mg·mL -1 (a) Top surface, (b) Side surface, 8 mg·mL -1 (c) Upper surface, (d) Side surface, 10 mg·mL -1 (e) upper surface, (f) side surface;
[0037] Figure 9 Comparison of electrical performance of silicon-based water-volt devices prepared in Example 3: (a) is the curve of open-circuit voltage of different silicon-based water-volt devices over time, and (b) is the curve of short-circuit current density of different silicon-based water-volt devices over time.
[0038] Figure 10 X-ray diffraction pattern of the hole-selective transport layer prepared for Comparative Example 3;
[0039] Figure 11 Comparison of the electrical performance of silicon-based water-volt devices prepared in Comparative Example 2 and Comparative Example 3: (a) is the curve of open-circuit voltage of different silicon-based water-volt devices over time, and (b) is the curve of short-circuit current density of different silicon-based water-volt devices over time.
[0040] Figure 12 The application of silicon-based water-voltaic devices in driving diode bulbs: (a) Voltage values of different numbers of silicon-based water-voltaic devices connected in series; (b) Image of an array of four silicon-based water-voltaic devices connected in series to drive a diode bulb. Detailed Implementation
[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.
[0042] The present invention will be further described below with reference to specific embodiments, so that those skilled in the art can better understand and implement the present invention, but the embodiments are not intended to limit the present invention.
[0043] Example 1
[0044] This embodiment provides a method for fabricating a high-efficiency silicon-based water-voltaic device. A schematic diagram of the silicon-based water-voltaic device is shown below. Figure 1 As shown, from top to bottom, it consists of a positive electrode, a hole-selective transport layer, a silicon nanostructure, a silicon substrate, and a negative electrode; the hole-selective transport layer is made of cobalt oxide; the specific preparation method is as follows:
[0045] (1) Cut the single-sided polished commercial silicon wafer into a square with an area of 2cm×2cm, and clean it in an ultrasonic cleaner with ultrapure water, acetone and ethanol in sequence for 15min each.
[0046] (2) Place the cleaned silicon wafer in a 5% HF aqueous solution for 10 minutes to remove the naturally grown silicon oxide film on the silicon surface.
[0047] (3) Immerse the silicon wafer in the silver plating solution (4.80 mol·L⁻¹). -1 HF, 0.01 mol·L -1 The silicon wafer was kept in AgNO3 for 40-60 seconds until it turned golden yellow. Then it was removed. At this point, a uniform layer of silver nanoparticles had been successfully deposited on the silicon surface.
[0048] (4) Quickly immerse the silver-plated silicon wafer in the etching solution (4.80 mol·L⁻¹). -1 HF, 0.03 mol·L -1 A silicon nanowire array with a length of 30 μm can be prepared by stirring with a magnetic stirrer and controlling the temperature to 40 °C for 50 min.
[0049] (5) Place the freshly prepared silicon nanowire array in a dilute nitric acid solution for 5 to 10 minutes to remove unreacted silver particles; rinse the silicon nanowire array repeatedly with ultrapure water to remove impurities.
[0050] (6) Figure 2As shown, cobalt acetate tetrahydrate (Co(OAc)₂·4H₂O) was dissolved in deionized water to prepare a solution with a mass concentration of 6 mg·mL⁻¹. -1 The solution was prepared by dropping 200 μL of acetic acid tetrahydrate precursor solution onto the surface of silicon nanowires using a pipette and letting it stand for 2 min. The substrate was then annealed at 150 °C for 30 min and treated with ultraviolet ozone for 30 min, thereby preparing a cobalt oxide film on the top of the silicon nanowire array.
[0051] (7) A 100nm aluminum film is deposited on the back of the silicon substrate using vacuum thermal evaporation as the negative electrode. Graphite / PEDOT:PSS / fabric is adhered to the cobalt oxide film with conductive adhesive as the positive electrode. Copper wires are then drawn out from the positive and negative electrodes with silver paste for easy testing. The silicon-based water-voltaic device is thus prepared.
[0052] The side and top surfaces of the silicon nanowire array with cobalt oxide thin film deposited in step (6) above were characterized by scanning electron microscopy (SEM), and the results are as follows: Figure 3 As shown in (a) and 3(b), cobalt oxide was successfully prepared at the top of the silicon nanowire array. The microstructure at three different locations perpendicular to the silicon nanowire array was further observed using scanning electron microscopy, as shown in... Figure 4 As shown, Figure 4 In the figure, A, B, and C correspond to the upper, middle, and lower positions of the silicon nanowire array, respectively. As shown, cobalt oxide is mainly distributed at the top of the silicon nanowire array, forming a radial heterojunction structure that is more conducive to charge transport and collection. Furthermore, the top portions of the silicon nanowires are embedded in the cobalt oxide, such as... Figure 5 As shown, the silicon nanowires and cobalt oxide form a surface contact, which is beneficial for improving the transport of holes at the interface.
[0053] Example 2
[0054] This embodiment provides a method for preparing a high-efficiency silicon-based water-voltaic device. The difference from Example 1 is that the mass concentration of the prepared cobalt acetate tetrahydrate (Co(OAc)2·4H2O) aqueous solution is 3 mg·mL. -1 All other operations are the same.
[0055] Example 3
[0056] This embodiment provides a method for preparing a high-efficiency silicon-based water-voltaic device. The difference from Example 1 is that the mass concentration of the prepared cobalt acetate tetrahydrate (Co(OAc)2·4H2O) aqueous solution is 8 mg·mL. -1 All other operations are the same.
[0057] Example 4
[0058] This embodiment provides a method for fabricating a high-efficiency silicon-based water-voltaic device. The difference from Embodiment 1 is that the hole-selective transport layer precursor solution prepared has a mass concentration of 8 mg·mL⁻¹. -1 The aqueous solution of nickel acetate tetrahydrate (Ni(CH3COO)2·4H2O) was prepared, and all other operations were the same.
[0059] Comparative Example 1
[0060] This comparative example provides a method for preparing a silicon-based water-voltaic device. The difference from Example 1 is that the mass concentration of the prepared cobalt acetate tetrahydrate (Co(OAc)2·4H2O) aqueous solution is 10 mg·mL. -1 All other operations are the same.
[0061] Comparative Example 2
[0062] This comparative example provides a method for fabricating a silicon-based water-voltaic device, in which a hole-selective transport layer is not prepared on the surface of silicon nanowires, but all other operations are the same.
[0063] Comparative Example 3
[0064] This comparative example provides a method for preparing a silicon-based water-based photovoltaic device. The difference from Example 1 is that the hole-selective transport layer precursor solution prepared has a mass concentration of 8 mg / mL. -1 The titanium tetrachloride aqueous solution was prepared, and all other operations were the same.
[0065] Performance Characterization and Application
[0066] 1. The effect of introducing cobalt oxide hole-selective transport layers of different thicknesses on the performance of silicon-based water-voltaic devices.
[0067] Different concentrations (3 mg·mL) were measured using scanning electron microscopy. -1 6 mg·mL -1 8 mg·mL -1 10 mg·mL -1 The thicknesses of the hole-selective transport layers prepared from the precursor solutions were ~100 nm, ~300 nm, ~500 nm, and ~1 μm, respectively.
[0068] The electrical performance of the silicon-based water-voltaic devices prepared in Examples 1-3 and Comparative Examples 1-2 was tested, and the results are as follows: Figure 6 As shown, Figure 6 (a) shows the open-circuit voltage of different silicon-based water-volt devices as a function of time. Figure 6 (b) shows the curves of short-circuit current density versus time for different silicon-based water-volt devices.
[0069] A water evaporation-induced power generation device based on a blank silicon nanowire array can continuously output an open-circuit voltage of 0.62V and an A·cm⁻¹. -2 The short-circuit current density (current density is calculated based on the effective area of the entire device); using a concentration of 3 mg·mL⁻¹ -1 Cobalt oxide films obtained by drop-coating cobalt acetate tetrahydrate (Co(OAc)₂·4H₂O) aqueous solution onto silicon nanowires followed by annealing and oxidation improved the open-circuit voltage and short-circuit current density of the corresponding silicon-based water-voltaic devices; and the effect of increasing cobalt acetate tetrahydrate aqueous solution concentration to 6 mg·mL⁻¹ further enhanced the open-circuit voltage and short-circuit current density. -1 The output performance of the water-based photovoltaic device is significantly improved, continuously generating an open-circuit voltage of 0.82V and a current of 36.0μA·cm⁻¹. -2 Short-circuit current density; however, with the continued increase of the concentration of cobalt acetate tetrahydrate aqueous solution, it increases to 10 mg·mL⁻¹. -1 At that time, the output performance of the water-voltaic device actually decreased, approaching the output performance without the introduction of a hole selective transport layer.
[0070] The peak power density of the above-mentioned different silicon-based water-voltaic devices under a 10KΩ load is as follows: Figure 7 As shown, with the increase of cobalt acetate tetrahydrate concentration, i.e. the increase of the thickness of the formed cobalt oxide film, the peak power density of the water-voltaic device first increases and then decreases.
[0071] Figure 8 To use different concentrations (3 mg·mL) -1 8 mg·mL -1 10 mg·mL -1 The cobalt oxide film prepared on silicon nanowire array by cobalt acetate tetrahydrate aqueous solution shows that the cobalt oxide film formed on the surface becomes denser with increasing concentration, which has a certain impact on water vapor evaporation.
[0072] 2. The impact of introducing a nickel oxide hole-selective transport layer on the performance of silicon-based water-voltaic devices
[0073] Example 4 shows the electrical performance of a silicon-based water-voltaic device fabricated using nickel oxide as the hole-selective transport layer. Figure 9 As shown, Figure 9 (a) shows the curve of the open-circuit voltage of the water-volt device changing over time. Figure 9 (b) shows the short-circuit current density of the water-evaporized device as a function of time. As can be seen from the figure, the water evaporation-induced power generation device containing a nickel oxide hole-selective transport layer can continuously output an open-circuit voltage of 0.80V and a current density of 35.0 μA·cm⁻¹. -2 The short-circuit current density is significantly higher than that of a blank silicon nanowire array water evaporation induced power generation device. The introduction of a nickel oxide hole selective transport layer significantly improves the output power of the water photovoltaic device.
[0074] 3. The impact of introducing an amorphous titanium dioxide hole-selective transport layer on the performance of silicon-based water-voltaic devices
[0075] The hole-selective transport layer prepared in Comparative Example 3 was characterized by X-ray diffraction, and the results are as follows: Figure 10 As shown, no diffraction peaks were observed, indicating that the titanium dioxide prepared in Comparative Example 3 was amorphous.
[0076] Comparison of the electrical performance of the silicon-based water-voltaic device fabricated using titanium dioxide as a hole-selective transport layer in Comparative Example 3 and the silicon-based water-voltaic device without a hole-selective transport layer in Comparative Example 2. Figure 11 As shown, Figure 11 (a) shows the open-circuit voltage of different silicon-based water-volt devices as a function of time. Figure 11 (b) shows the curves of short-circuit current density versus time for different silicon-based water-volt devices.
[0077] Furthermore, this invention prepared titanium oxide hole-selective transport layers of different thicknesses (100 nm, 300 nm, 500 nm, 800 nm) by adjusting the concentration of titanium tetrachloride. The electrical performance of the corresponding silicon-based water-voltaic devices is shown in Table 1 below:
[0078] Table 1
[0079] Titanium oxide thickness (nm) Open circuit voltage (V) <![CDATA[Short-circuit current density (μA·cm -2 )]]> 0 0.62 29.0 100 0.53 23.8 300 0.45 22.1 500 0.31 20.9 800 0.22 18.8
[0080] As shown in Table 1, the open-circuit voltage and short-circuit current density of silicon-based water-voltaic devices containing different thicknesses of titanium dioxide hole-selective transport layers are much smaller than those of the silicon-based water-voltaic device without a hole-selective transport layer in Comparative Example 2.
[0081] 3. Application
[0082] The silicon-based water-voltaic device prepared in Example 1 was used to drive a diode light bulb, such as... Figure 12 As shown in (a), the voltage of the four silicon-based water-voltaic devices prepared in Example 1, when connected in series, increases linearly to nearly 3V, successfully driving an array of 25 red, white, green, and purple diode bulbs. Figure 12 (b)).
[0083] In summary, the hole-selective transport layer prepared by introducing cobalt oxide between the positive electrode and the silicon nanostructure can effectively improve the output power of silicon-based water-voltaic devices. However, the introduction of an excessively thick cobalt oxide hole-selective transport layer will reduce the output power of silicon-based water-voltaic devices.
[0084] The above-described embodiments are merely preferred embodiments provided to fully illustrate the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention. The scope of protection of the present invention is defined by the claims.
Claims
1. A high-efficiency silicon-based water-voltaic device, characterized in that, The silicon-based water-voltaic device is composed of a positive electrode, a hole-selective transport layer, a silicon nanostructure, a silicon substrate, and a negative electrode from top to bottom. The top part of the silicon nanostructure is embedded in the hole-selective transport layer. The hole-selective transport layer is made of one or more of cobalt oxide, tungsten oxide, vanadium oxide, and nickel oxide; the thickness of the hole-selective transport layer is 50 nm to 800 nm; and the silicon nanostructure is a silicon nanowire, silicon nanopore, silicon nanocone, silicon nanopillar, or silicon pyramid.
2. The high-efficiency silicon-based water-voltaic device according to claim 1, characterized in that, The hole-selective transport layer is made of cobalt oxide and / or nickel oxide.
3. The high-efficiency silicon-based water-voltaic device according to claim 1, characterized in that, The thickness of the hole-selective transport layer is 100 nm to 500 nm.
4. The high-efficiency silicon-based water-voltaic device according to claim 1, characterized in that, The high-efficiency silicon-based water-voltaic device further includes an electron-selective transport layer disposed between the silicon substrate and the negative electrode; the material of the electron-selective transport layer is one or more of magnesium oxide, titanium oxide, niobium oxide, barium oxide, tin oxide, and tantalum oxide.
5. The high-efficiency silicon-based water-voltaic device according to claim 1, characterized in that, The positive electrode is a carbon nanotube fabric electrode, a graphite fabric electrode, a grid electrode, a gold grid electrode, or a graphite / PEDOT:PSS / fabric electrode; the negative electrode is a gold electrode, a silver electrode, or an aluminum electrode.
6. A method for fabricating a high-efficiency silicon-based photovoltaic device according to any one of claims 1 to 5, characterized in that, The process includes the following steps: a hole-selective transport layer precursor solution is spin-coated, drop-coated or inkjet-printed onto the surface of a pretreated silicon nanostructure, annealed and then oxidized under ultraviolet ozone to form the hole-selective transport layer on top of the silicon nanostructure. The top portion of the silicon nanostructure is embedded in the hole-selective transport layer.
7. The preparation method according to claim 6, characterized in that, The hole-selective transport layer precursor solution is cobalt acetate tetrahydrate; the concentration of the hole-selective transport layer precursor solution is 3~8 mg·mL. -1 .
8. The preparation method according to claim 7, characterized in that, The pretreatment specifically involves placing the prepared silicon nanostructure in dilute nitric acid and letting it stand for 5-10 minutes to remove unreacted silver particles, followed by rinsing with ultrapure water to remove impurities, thus obtaining the pretreated silicon nanostructure.