One-dimensional silicon-doped black phosphorus fiber, preparation method thereof, and ultraviolet photoelectric device

Abstract

The present invention provides a one-dimensional silicon-doped black phosphorus fiber, a preparation method thereof, and an ultraviolet photoelectric device, comprising: (1) mixing iodine and silicon powder and placing them in a quartz tube, vacuum-sealing the quartz tube, burying the quartz tube in glass powder, heating to 700-900°C, and keeping the temperature, to obtain a silicon-iodine compound; (2) mixing amorphous red phosphorus, tin powder, and a silicon-iodine compound and placing them in a quartz tube, vacuum-sealing the quartz tube, burying the quartz tube in glass powder, heating to 620-650°C, and keeping the temperature; then cooling to 450-500°C and keeping the temperature, to obtain a one-dimensional BP-Si fiber. This method can effectively introduce silicon and realize the controllable growth of one-dimensional BP fiber, on this basis forming a Schottky junction with Ag to improve its photoelectric detection performance, which is conducive to the large-scale production and industrial application of BP-based photoelectric devices.

Description

Technical Field

[0001] The present invention belongs to the technical field of one-dimensional black phosphorus preparation, and in particular relates to a one-dimensional silicon-doped black phosphorus (BP-Si) fiber, a preparation method thereof, and an ultraviolet photoelectric device. Background Art

[0002] Photodetectors are important optoelectronic components that can convert received optical signals into electrical signals. They are widely used in optoelectronic imaging, optical communications, optical detection, and other fields. Among them, black phosphorus (BP) is an emerging layered semiconductor material with an adjustable direct band gap (0.3eV to 2.0eV), high carrier mobility (1000cm 2 V -1 S -1 ), high light conversion efficiency, and other excellent properties, which can significantly enhance the photoelectric coupling efficiency. Compared with bulk and two-dimensional BP materials, one-dimensional BP structure has advantages such as higher specific surface area, quantum confinement effect, higher carrier mobility and faster carrier response speed, making it an ideal material for the preparation of high-performance photodetectors.

[0003] Although BP materials have unique advantages, there are some problems that need to be solved in practical applications. First, there are lone pairs of electrons on the P atoms on the surface and edges of BP, and the electron activity is very high, which is prone to oxidative degradation. It is necessary to find effective methods to improve the stability of BP and extend its service life in practical photoelectric detection applications. Secondly, the preparation methods of BP materials mainly include mechanical exfoliation and solution ultrasonic methods. The morphology obtained is generally bulk and two-dimensional BP materials. There is a lack of effective preparation methods for long-sized, highly stable one-dimensional BP materials. These problems hinder the application and development of BP-based photodetectors. In the currently published patent reports, such as CN116675192A, a method for preparing silicon-doped black phosphorus is disclosed. Black phosphorus is placed in a plasma vapor deposition device, and a radio frequency power supply is used to continuously ionize the silicon- and phosphorus-containing gases in the device, and then the black phosphorus surface is treated to obtain Si-doped BP material. However, since BP and doping are not prepared in one step, and Si doping is not introduced in situ during the growth of BP, this method has the disadvantages of low doping efficiency and uneven doping. In addition, this method has strict requirements on vacuum and high temperature, which is not conducive to the large-scale industrial production of BP-doped materials. A patent document discloses a method for preparing black phosphorus and doping black phosphorus by vapor phase transport. Red phosphorus, tin powder and a transfer agent are mixed and placed at the high-temperature end of a sealed chamber. After heating and heat preservation, black phosphorus crystals are obtained at the low-temperature end. Since this vapor phase doping method is carried out in an open tubular furnace, in addition to the problem of uneven temperature, there are safety hazards and it is not suitable for silicon doping at higher temperatures. Based on the above technical problems, how to prepare one-dimensional BP and its in-situ doping more stably, efficiently and at low cost, and prepare a complex fiber composite structure - a black phosphorus fiber composite material supported by a silicon doping source through a one-step method, realize the controllable doping of high melting point doping sources and uniform Si doping at low temperature to improve BP stability, and realize the support of nano-sized silicon on the fiber structure, has important academic significance and practical application value for improving the performance of BP-based optoelectronic devices. Summary of the Invention

[0004] Based on the technical problems existing in the above-mentioned prior art, the present invention provides a one-dimensional silicon-doped black phosphorus fiber, a preparation method thereof, and an ultraviolet photoelectric device. This method can effectively introduce silicon elements and realize the controllable growth of one-dimensional BP fibers. On this basis, a Schottky junction is formed with Ag to improve its photoelectric detection performance, which is conducive to the large-scale production and industrial application of BP-based photoelectric devices.

[0005] The present invention is achieved through the following technical solutions:

[0006] A method for preparing one-dimensional silicon-doped black phosphorus fibers comprises the following steps:

[0007] (1) Iodine and silicon powder are mixed in a mass ratio of 20 mg: (1-3) mg and placed in a quartz tube. After the quartz tube is vacuum-sealed, the quartz tube is buried in glass powder and heated to 700-900° C., kept warm, and the product is washed and dried to obtain a silicon-iodine compound;

[0008] (2) Amorphous red phosphorus, tin powder, and silicon iodine compound are mixed and placed in a quartz tube, and the quartz tube is vacuum-sealed, wherein the mass ratio of amorphous red phosphorus to silicon iodine compound is 400 mg:(21-23) mg; the quartz tube is buried in glass powder and heated to 620-650°C and kept warm; then the temperature is lowered to 450-500°C and kept warm; the product is washed and dried to obtain a one-dimensional BP-Si fiber.

[0009] Preferably, in step (1), the holding time is 300 to 360 minutes.

[0010] Preferably, in step (1), the average size of the silicon powder is 20 to 50 nm.

[0011] Furthermore, in step (1), the silicon powder is prepared by wet ball milling silicon powder with a particle size of 100 to 300 mesh, wherein the grinding balls used in the ball milling are zirconium oxide with a diameter of 5 to 10 mm, and the ball milling solvent is anhydrous ethanol.

[0012] Preferably, in step (2), the temperature is kept at 620-650° C. for 300-360 minutes; and the temperature is kept at 450-500° C. for 240-300 minutes.

[0013] Preferably, in step (1) and step (2), the melting point of the glass powder is 500-550°C.

[0014] The invention provides one-dimensional silicon-doped black phosphorus fiber obtained by adopting the preparation method.

[0015] The present invention provides an ultraviolet photoelectric device, comprising a substrate, on which the above-mentioned one-dimensional silicon-doped black phosphorus fibers and Ag interdigital electrodes are sequentially deposited.

[0016] Preferably, the substrate is a Si / SiO2 substrate.

[0017] The method for preparing the ultraviolet photoelectric device of the present invention comprises: adding one-dimensional BP-Si fibers to an isopropyl alcohol solution, ultrasonically obtaining a BP-Si fiber dispersion; applying droplets of the BP-Si fiber dispersion on a substrate, and drying; and then vacuum evaporating Ag interdigital electrodes to obtain the ultraviolet photoelectric device.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The main advantage of the present invention is the invention of a highly stable black phosphorus preparation method. Using amorphous red phosphorus as the phosphorus source, iodine silicon compounds as the silicon and iodine sources, tin as the catalyst, and iodine as the transport agent, the controllable preparation of one-dimensional BP-Si fibers of millimeter size is successfully achieved. Furthermore, in-situ doping of Si is successfully achieved, which improves the stability of the BP lattice structure and allows BP to exist stably in an air environment for a long time. This method ensures uniform temperature and good insulation within the quartz tube, which is conducive to the uniform growth of long-length BP-Si fibers. After heating, the silicon-iodine compound slowly decomposes into gaseous silicon and iodine atoms under the action of the catalyst tin. These gaseous atoms will react with the vaporized red phosphorus and tin, thus effectively overcoming the problem of silicon and iodine source consumption in the precursor I-Si-P-Sn during the reaction. This ensures the continued growth of one-dimensional BP-Si fibers from the source, ultimately achieving the controlled growth of ultra-long fibers and the controlled loading of silicon nanoparticles. Therefore, compared to the direct addition of silicon and iodine powders, the silicon-iodine compound not only achieves controlled silicon doping at low temperatures and efficient and uniform loading of silicon nanoparticles onto the fibers, but also avoids the high pressures associated with the vaporization of excess iodine vapor at high temperatures, resulting in a more controllable reaction, more uniform doping, and the successful loading of silicon nanoparticles onto fibrous black phosphorus. Si doping effectively modulates the electronic structure of BP, improving its charge transport properties, carrier mobility, chemical stability, and structural stability. In addition to Si atomic doping within the lattice, Si nanoparticles can also be stably loaded onto the BP fiber surface, forming a BP / Si heterojunction. This heterojunction utilizes its built-in electric field to effectively separate photogenerated carriers and facilitate carrier transport, thereby enhancing the performance of BP-based photodetectors. Scanning electron microscopy (SEM) images, transmission electron microscopy (TEM) images, and XRD spectra reveal that the one-dimensional BP-Si fibers reach millimeter-scale dimensions and exhibit excellent crystallinity, facilitating the integrated application of BP-based optoelectronic devices. This preparation method, with its simple structure and low process threshold, is highly suitable for large-scale production and provides a reliable solution for the development of high-performance BP-Si optoelectronic devices.

[0020] The present invention deposits silver interdigital electrodes on BP-Si fibers to prepare Ag / BP-Si single fiber ultraviolet photoelectric devices. The Schottky junction formed by Ag and BP-Si inhibits the recombination of photogenerated carriers, thereby improving the light response speed and photoelectric performance. The present invention conducts IV characteristic curves of the Ag / BP-Si fiber photoelectric device under dark conditions and under 365nm ultraviolet light irradiation (see attached). Figure 5 ), and IT curve test under 5V bias under UV conditions (see Appendix Figure 6 The results show that the Ag / BP-Si fiber device has a low dark current, which is 2.6×10 -9 A, and the photocurrent after UV irradiation was 1.6×10 -6 A, the on-off ratio is 615. This shows that the Ag / BP-Si fiber device can effectively suppress the dark current and significantly improve the photocurrent, on-off ratio and cycle stability after UV illumination, confirming that the Ag / BP-Si fiber device has good application prospects in the field of UV optoelectronic devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 This is a physical picture of the BP-Si fiber samples prepared from silicon powder of different qualities in the present invention.

[0023] Figure 2 This is the SEM image of the one-dimensional BP-Si fiber in the present invention.

[0024] Figure 3 This is the TEM image of the one-dimensional BP-Si fiber in the present invention.

[0025] Figure 4 This is the XRD pattern of the one-dimensional BP-Si fiber in the present invention.

[0026] Figure 5 1 is the IV characteristic curve of the fiber device in the present invention in the dark state and under 365nm ultraviolet light.

[0027] Figure 6 This is the IT curve of the fiber device in the present invention under 365nm ultraviolet light and 5V bias. DETAILED DESCRIPTION

[0028] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention.

[0029] It should be noted that the process equipment or devices not specifically specified in the following embodiments are all conventional equipment or devices in the art.

[0030] It should be noted that the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products, or apparatuses. Furthermore, unless otherwise specified, the numbering of each method step is merely a convenient tool for identifying each method step, and is not intended to limit the order of arrangement of each method step or to define the scope of the invention. Changes or adjustments to their relative relationships, without substantially changing the technical content, should also be considered within the scope of the invention.

[0031] The method for preparing the one-dimensional silicon-doped black phosphorus fiber of the present invention comprises the following steps:

[0032] (1) Preparation of silicon-iodine compound: Iodine and silicon powder are evenly mixed in a ratio of 20 mg: (1-3) mg and placed in a quartz tube. After the quartz tube is vacuum-sealed, the quartz tube is buried in glass powder and heated to 700-900°C, kept warm for 300-360 minutes, and finally cooled naturally to room temperature; the product is washed and dried to obtain a silicon-iodine compound.

[0033] (2) Preparation of BP-Si fiber: Amorphous red phosphorus, tin powder, and silicon iodine compound are mixed in a ratio of 400 mg: 40 mg: (21-23) mg and placed in a quartz tube. The quartz tube is vacuum-sealed and buried in glass powder. The tube is heated to 620-650°C and kept warm for 300-360 minutes to promote the vaporization of red phosphorus, iodine, silicon, tin and other substances and to fully react at the atomic scale to form a P-Si-I-Sn fibrous precursor; the temperature is then lowered to 450-500°C and kept warm for 240-300 minutes to promote the fibrous precursor to stably grow ultra-long BP-Si fibers, and finally naturally cooled to room temperature; the product is washed and dried to obtain a one-dimensional BP-Si fiber.

[0034] In the method described in the present invention, the average size of the silicon powder used is 20 to 50 nm, and the preparation method is as follows: silicon powder with a particle size of 100 to 300 meshes and zirconium oxide grinding balls with a diameter of 5 to 10 mm (ball-to-material ratio of 10 to 20:1) are placed in a ball mill, and anhydrous ethanol is added to completely immerse the silicon powder, and ball milling is carried out at a speed of 400 to 700 r / min for 30 to 50 hours; the ball-milled silicon powder is ultrasonically cleaned with anhydrous ethanol and deionized water for 3 to 5 times respectively, and dried after centrifugal solid-liquid separation to obtain silicon powder with an average size of 20 to 50 nm.

[0035] After heating, the silicon-iodine compound will slowly decompose into gaseous silicon and iodine atoms under the action of a catalyst. These gaseous atoms will react with vaporized red phosphorus and tin, thus effectively overcoming the problem of silicon and iodine source consumption in the precursor I-Si-P-Sn during the reaction. This ensures the continued growth of one-dimensional BP-Si fibers from the source, ultimately achieving controlled growth of ultra-long fibers and controlled loading of silicon nanoparticles. Therefore, compared to directly adding silicon powder and iodine powder, the silicon-iodine compound not only achieves controlled silicon doping at low temperatures and effective and uniform loading of silicon nanoparticles on the fibers, but also avoids the dangers of high pressure caused by the vaporization of excess iodine vapor at high temperatures, making the reaction more controllable, the doping more uniform, and achieving the loading of silicon nanoparticles on the fiber black phosphorus.

[0036] The quartz tube heating process is achieved using a chemical vapor transport (CVT) liquid bath constant temperature method. Specifically, the quartz tube is completely immersed in a stainless steel device filled with glass powder. The glass powder (in the ratio of ZnO:Bi2O3:SiO2:PbO:Na2O:Al2O3:B2O3 = 2% to 15%:5% to 10%:12% to 14%:40% to 50%:15% to 20%:6% to 7%:1% to 3%) becomes liquid when heated to 500 to 550°C. This liquid bath environment ensures uniform temperature distribution within the quartz tube and provides excellent thermal insulation, which is conducive to the uniform growth of long BP-Si fibers. It also provides a good buffering effect on the outside of the quartz tube, effectively absorbing and alleviating some of the stress generated during the reaction and preventing the risk of explosion.

[0037] Based on the one-dimensional BP-Si fiber obtained in the present invention, an Ag / BP-Si fiber optoelectronic device is prepared, specifically as follows:

[0038] A one-dimensional BP-Si fiber sample was added to an isopropyl alcohol solution and ultrasonicated for 20 to 30 minutes to obtain a BP-Si fiber dispersion. The BP-Si fiber dispersion was dropwise coated on a Si / SiO2 substrate and dried. Ag interdigital electrodes were then vacuum evaporated to obtain an Ag / BP-Si fiber optoelectronic device.

[0039] Cleaning the Si / SiO2 substrate is a crucial step in the fabrication of Ag / BP-Si optoelectronic devices. Organic wet cleaning is primarily used to remove organic solvents and adhesive protective layers from the substrate surface, which can affect the device's optoelectronic performance. Specifically, the Si / SiO2 substrate is ultrasonically cleaned with acetone, ethanol, and deionized water for 10-15 minutes each, then dried in an oven at 60°C for 180-240 minutes.

[0040] Example 1:

[0041] (1) Preparation of silicon powder: 200-mesh silicon powder and 7-mm-diameter zirconium oxide grinding balls (ball-to-material ratio 15:1) were placed in a ball mill. Anhydrous ethanol was added to completely submerge the silicon powder. The powder was ball milled at 500 r / min for 45 hours. The milled silicon powder was ultrasonically cleaned five times with anhydrous ethanol and five times with deionized water, respectively. After centrifugal solid-liquid separation, the powder was dried to obtain silicon powder with an average size of 20 to 50 nm.

[0042] (2) Preparation of silicon-iodine compound: Iodine and ball-milled silicon powder were mixed in a ratio of 20 mg:3 mg and placed in a quartz tube. The quartz tube was vacuum-sealed using a hydrogen flame tube sealer and then embedded in glass powder. The quartz tube was heated to 800°C over 300 minutes, kept at this temperature for 330 minutes, and finally cooled naturally to room temperature. The removed compound was ultrasonically cleaned five times with deionized water, centrifuged for solid-liquid separation, and then dried to obtain the silicon-iodine compound.

[0043] (3) Preparation of BP-Si fiber: Amorphous red phosphorus, tin powder, and silicon iodine compound are mixed evenly in a ratio of 400mg:40mg:23mg and placed in a quartz tube. The quartz tube is vacuum sealed with a hydrogen flame tube sealing machine, and then buried in low-melting-point glass powder (the ratio is ZnO:Bi2O3:SiO2:PbO:Na2O:Al2O3:B2O3=2%:10%:14%:50%:15%:6%:3%, melting point is 550℃). Place the quartz tube flat in the center of the muffle furnace, heat to 630℃ within 200 minutes, and keep warm for 300 minutes. Then cool to 485℃ after 480 minutes, keep warm for 240 minutes, and finally cool naturally to room temperature. After the muffle furnace cools down, take out the quartz tube, such as Figure 1 As shown, when the amount of silicon powder was 3 mg, clustered BP fibers were formed. The BP-Si fiber sample was thoroughly washed with hot toluene (~60°C) and dried in a N2 atmosphere to obtain BP-Si fibers, which were then stored in a glove box for future use.

[0044] (4) Preparation of Ag / BP-Si optoelectronic devices: The Si / SiO2 substrate was ultrasonically cleaned with acetone, ethanol, and deionized water for 10 minutes, respectively, and dried in an oven at 60°C for 2-10 minutes. The BP-Si fiber sample was added to 5 ml of isopropanol solution and ultrasonicated for 25 minutes to obtain a BP-Si fiber dispersion. The BP-Si fiber dispersion was dropwise applied to the Si / SiO2 substrate using a pipette and dried in an oven at 60°C. The substrate was then placed in a vacuum evaporator and an interdigitated electrode mask with a horizontal spacing of 40 μm was used for electrode preparation to obtain an Ag / BP-Si fiber optoelectronic device.

[0045] Figure 2(a), (b), and (c) show scanning electron microscope (SEM) images at different scales. It can be seen that the morphology of the BP-Si sample is fiber-like, with a size of up to millimeter level, and a small amount of particles are attached to the fiber. The energy spectrum characterization of a single fiber is performed, such as Figure 2 In (d), (e), and (f), it was found that the main constituent element of the fiber was phosphorus, and the main constituent element of the particles loaded on the fiber surface was silicon, indicating that the BP fiber was loaded with silicon particles. In order to further verify the quality of the generated sample crystals, transmission electron microscopy (TEM) characterization was performed. Figure 3 As shown in (a), (b) and (c), most of the fibers have good crystallinity during TEM characterization, and the generated BP-Si material crystals are of good quality. High-resolution transmission electron microscopy (HRTEM) images show obvious lattice fringes. Figure 3 (d) and (e) show the (040) and (020) crystal planes of phosphorus in BP-Si material. The lattice spacing of the (040) crystal plane is The lattice spacing of the (020) crystal plane is like Figure 3 In (d), the (111) crystal plane of silicon is also clearly found, and the lattice spacing is The XRD data of BP-Si fiber is shown in Figure 4 The results show that the overall crystallinity is good. The (020) crystal plane of BP can be observed at 16.8° in the XRD pattern with high intensity, and the characteristic peak of silicon can also be observed.

[0046] In order to test the photoelectric performance of Ag / BP-Si fiber photoelectric devices, IV characteristic curves were obtained under dark conditions and 365 nm UV irradiation (see Appendix Figure 5 ), and IT curve test under 5V bias under UV conditions (see Appendix Figure 6 The results show that the Ag / BP-Si fiber device has a low dark current, which is 2.6×10 -9 A, and the photocurrent after UV irradiation was 1.6×10 -6 A, the on-off ratio is 615, indicating that the Ag / BP-Si fiber device can effectively suppress the dark current and significantly improve the photocurrent, on-off ratio and cycle stability after ultraviolet light irradiation. The Ag / BP-Si fiber device has good photoelectric performance.

[0047] Example 2:

[0048] (1) Preparation of silicon powder: 100-mesh silicon powder and 5-mm-diameter zirconium oxide grinding balls (ball-to-material ratio 10:1) were placed in a ball mill. Anhydrous ethanol was added to completely submerge the silicon powder. The powder was ball milled at 400 rpm for 30 hours. The milled silicon powder was ultrasonically cleaned three times with anhydrous ethanol and three times with deionized water, respectively. After centrifugal solid-liquid separation, the powder was dried to obtain silicon powder with an average size of 20 to 50 nm.

[0049] (2) Preparation of silicon-iodine compound: Iodine and ball-milled silicon powder were mixed in a ratio of 20 mg:1 mg and placed in a quartz tube. The quartz tube was vacuum-sealed using a hydrogen flame tube sealer and then embedded in the glass powder. The quartz tube was heated to 700°C over 300 minutes, kept at this temperature for 300 minutes, and finally cooled naturally to room temperature. The removed compound was ultrasonically cleaned three times with deionized water, centrifuged for solid-liquid separation, and then dried to obtain the silicon-iodine compound.

[0050] (3) Preparation of BP-Si fiber: Amorphous red phosphorus, tin powder, and silicon iodine compound are mixed evenly in a ratio of 400 mg: 40 mg: 21 mg and placed in a quartz tube. The quartz tube is vacuum sealed with a hydrogen flame tube sealing machine, and then buried in low-melting-point glass powder (the ratio is ZnO: Bi2O3: SiO2: PbO: Na2O: Al2O3: B2O3 = 15%: 5%: 12%: 40%: 20%: 7%: 1%, with a melting point of 500°C). The quartz tube is placed flat in the center of the muffle furnace, heated to 620°C within 200 minutes, and kept warm for 360 minutes. Then, it is cooled to 450°C after 480 minutes, kept warm for 270 minutes, and finally cooled naturally to room temperature. After the muffle furnace cools down, take out the quartz tube, such as Figure 1 As shown, when the amount of silicon powder was 1 mg, BP crystals were formed without significant effects. The sample was thoroughly washed with hot toluene (~60°C) and dried in a N2 atmosphere to obtain BP-Si fibers, which were then stored in a glove box for future use.

[0051] (4) Preparation of Ag / BP-Si optoelectronic devices: The Si / SiO2 substrate was ultrasonically cleaned with acetone, ethanol, and deionized water for 10 minutes, respectively, and dried in an oven at 60°C for 180 minutes. The BP-Si fiber sample was added to 5 ml of isopropanol solution and ultrasonicated for 20 minutes to obtain a BP-Si fiber dispersion. The BP-Si fiber dispersion was dropwise applied to the Si / SiO2 substrate using a pipette and dried in an oven at 60°C. The substrate was then placed in a vacuum evaporator and an interdigitated electrode mask with a horizontal spacing of 40 μm was used for electrode preparation to obtain an Ag / BP-Si fiber optoelectronic device.

[0052] Example 3:

[0053] (1) Preparation of silicon powder: 100-mesh silicon powder and 5-mm-diameter zirconium oxide grinding balls (ball-to-material ratio 10:1) were placed in a ball mill. Anhydrous ethanol was added to completely submerge the silicon powder. The powder was ball milled at 400 rpm for 30 hours. The milled silicon powder was ultrasonically cleaned three times with anhydrous ethanol and three times with deionized water, respectively. After centrifugal solid-liquid separation, the powder was dried to obtain silicon powder with an average size of 20 to 50 nm.

[0054] (2) Preparation of silicon-iodine compound: Iodine and ball-milled silicon powder were mixed in a ratio of 20 mg:3 mg and placed in a quartz tube. The quartz tube was vacuum-sealed using a hydrogen flame tube sealer and then embedded in the glass powder. The quartz tube was heated to 900°C over 300 minutes, kept at this temperature for 300 minutes, and finally cooled naturally to room temperature. The removed compound was ultrasonically cleaned three times with deionized water, centrifuged for solid-liquid separation, and then dried to obtain the silicon-iodine compound.

[0055] (3) Preparation of BP-Si fiber: Amorphous red phosphorus, tin powder, and silicon iodine compound were mixed in a ratio of 400 mg: 40 mg: 23 mg and placed in a quartz tube. The quartz tube was vacuum sealed with a hydrogen flame tube sealer and then buried in low-melting-point glass powder (the ratio of ZnO: Bi2O3: SiO2: PbO: Na2O: Al2O3: B2O3 = 15%: 5%: 12%: 40%: 20%: 7%: 1%, melting point 500°C). The quartz tube was placed flat in the center of a muffle furnace, heated to 650°C within 200 minutes, and kept at this temperature for 330 minutes. Then, the temperature was lowered to 500°C over 480 minutes, kept at this temperature for 300 minutes, and finally cooled naturally to room temperature. After the muffle furnace cooled, the quartz tube was removed. The sample was washed thoroughly with hot toluene (~60°C) and dried in a N2 atmosphere to obtain BP-Si fiber, which was then placed in a glove box for future use.

[0056] (4) Preparation of Ag / BP-Si optoelectronic devices: The Si / SiO2 substrate was ultrasonically cleaned with acetone, ethanol, and deionized water for 10 minutes, respectively, and dried in an oven at 60°C for 180 minutes. The BP-Si fiber sample was added to 5 ml of isopropanol solution and ultrasonicated for 20 minutes to obtain a BP-Si fiber dispersion. The BP-Si fiber dispersion was dropwise applied to the Si / SiO2 substrate using a pipette and dried in an oven at 60°C. The substrate was then placed in a vacuum evaporator and an interdigitated electrode mask with a horizontal spacing of 40 μm was used for electrode preparation to obtain an Ag / BP-Si fiber optoelectronic device.

[0057] Comparative Example 1:

[0058] (1) Preparation of silicon powder: The same as step (1) in Example 1.

[0059] (2) Preparation of silicon-iodine compound: Iodine and ball-milled silicon powder were mixed in a ratio of 20 mg:5 mg and placed in a quartz tube. The quartz tube was vacuum-sealed using a hydrogen flame tube sealer and then embedded in the glass powder. The quartz tube was heated to 800°C over 300 minutes, kept at this temperature for 330 minutes, and finally cooled naturally to room temperature. The removed compound was ultrasonically cleaned five times with deionized water, centrifuged for solid-liquid separation, and then dried to obtain the silicon-iodine compound.

[0060] (3) Preparation of BP-Si fiber: Amorphous red phosphorus, tin powder, and silicon iodine compound are mixed in a ratio of 400 mg: 40 mg: 25 mg and placed in a quartz tube. The quartz tube is vacuum sealed with a hydrogen flame tube sealing machine, and then buried in low-melting-point glass powder (the ratio is ZnO: Bi2O3: SiO2: PbO: Na2O: Al2O3: B2O3 = 2%: 10%: 14%: 50%: 15%: 6%: 3%, with a melting point of 550°C). The quartz tube is placed flat in the center of the muffle furnace, heated to 630°C within 200 minutes, and kept warm for 300 minutes. The quartz tube is then cooled to 485°C after 480 minutes, kept warm for 240 minutes, and finally cooled naturally to room temperature. After the muffle furnace cools down, take out the quartz tube, as shown in the attached Figure 1 As shown, when the amount of silicon powder was 5 mg, no BP was formed.

[0061] Compared to Example 1, Comparative Example 1 differs only in the amount of silicon powder used. The amount of silicon powder used in Example 1 is 3 mg, while that in Comparative Example 1 is 5 mg. Consequently, BP cannot be formed in Comparative Example 1. Therefore, excessive silicon powder usage is detrimental to BP preparation.

[0062] Comparative Example 2:

[0063] (1) Preparation of silicon powder: The same as step (1) in Example 1.

[0064] (2) Preparation of silicon iodine compound: the same as step (2) in Example 1.

[0065] (3) Preparation of BP-Si fiber: Amorphous red phosphorus, tin powder, and silicon iodine compound were mixed in a ratio of 400 mg: 40 mg: 23 mg and placed in a quartz tube. The quartz tube was vacuum-sealed using a hydrogen flame tube sealer and then buried in low-melting-point glass powder (ratio of ZnO: Bi2O3: SiO2: PbO: Na2O: Al2O3: B2O3 = 2%: 10%: 14%: 50%: 15%: 6%: 3%, melting point 550°C). The quartz tube was placed flat in the center of a muffle furnace and heated to 630°C within 200 minutes. The temperature was maintained for 300 minutes, and the quartz tube was then naturally cooled to room temperature. After the muffle furnace cooled, the quartz tube was removed and no BP was found to have formed.

[0066] Steps (1) and (2) of Comparative Example 2 are the same as the corresponding steps of Example 1, and only step (3) is different. Step (3) of Comparative Example 2 only has the first stage, which is to heat to 630°C and keep warm for 300 minutes to promote the vaporization of substances such as red phosphorus, iodine, silicon, and tin and fully react at the atomic scale to form a P-Si-I-Sn fibrous precursor. There is no second stage, which is to cool to 485°C and keep warm for 240 minutes to promote the fibrous precursor to stably grow ultra-long BP-Si fibers. Therefore, the second stage of step three is very important for the growth of BP-Si fibers and is an indispensable preparation step.

[0067] Finally, a few points should be explained: Although the present invention has been described in detail above with general descriptions and specific embodiments, on the basis of the present invention, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for preparing one-dimensional silicon-doped black phosphorus fibers, characterized in that: The steps include: (1) Iodine and silicon powder are mixed in a mass ratio of 20 mg: (1-3) mg and placed in a quartz tube. After the quartz tube is vacuum-sealed, the quartz tube is buried in glass powder with a melting point of 500-550 °C and heated to 700-900 °C. The mixture is kept warm, and the product is washed and dried to obtain a silicon-iodine compound. (2) Amorphous red phosphorus, tin powder, and silicon iodine compound were mixed and placed in a quartz tube, which was vacuum-sealed. The mass ratio of amorphous red phosphorus to silicon iodine compound was 400 mg:(21~23) mg. The quartz tube was buried in glass powder with a melting point of 500~550℃, heated to 620~650℃, and kept warm. The temperature was then lowered to 450~500℃ and kept warm. The product was washed and dried to obtain a one-dimensional BP-Si fiber.

2. The method for preparing one-dimensional silicon-doped black phosphorus fiber according to claim 1, characterized in that: In step (1), the holding time is 300 to 360 minutes.

3. The method for preparing one-dimensional silicon-doped black phosphorus fiber according to claim 1, characterized in that: In step (1), the average size of the silicon powder is 20-50 nm.

4. The method for preparing one-dimensional silicon-doped black phosphorus fiber according to claim 3, characterized in that: In step (1), the silicon powder is prepared by wet ball milling silicon powder with a particle size of 100-300 mesh, wherein the grinding balls used in the ball milling are zirconium oxide with a diameter of 5-10 mm, and the ball milling solvent is anhydrous ethanol.

5. The method for preparing one-dimensional silicon-doped black phosphorus fiber according to claim 1, characterized in that: In step (2), the temperature is kept at 620-650°C for 300-360 minutes; and the temperature is kept at 450-500°C for 240-300 minutes.

6. One-dimensional silicon-doped black phosphorus fiber obtained by the preparation method according to any one of claims 1 to 5.

7. An ultraviolet photoelectric device, characterized in that: The method comprises a substrate, on which the one-dimensional silicon-doped black phosphorus fiber and Ag interdigital electrodes according to claim 6 are sequentially deposited.

8. The ultraviolet photoelectric device according to claim 7, characterized in that: The substrate is a Si / SiO2 substrate.

9. The method for preparing the ultraviolet photoelectric device according to claim 7, characterized in that: include: One-dimensional BP-Si fibers were added into isopropyl alcohol solution and ultrasonicated to obtain BP-Si fiber dispersion; The BP-Si fiber dispersion droplets are applied on the substrate and dried; Then, Ag interdigital electrodes are vacuum evaporated to obtain a UV photoelectric device.

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