Nanoparticulate noble metal structures, methods for their production and use

Abstract

This invention discloses a nanostructure of noble metals, its preparation method, and its applications. The nanostructure of noble metals includes a block copolymer template and a noble metal loaded on the block copolymer template. The block copolymer template is assembled from at least one of PS-P2VP and PS-P4VP, and the noble metal is at least one of Au, Ag, Pt, and Pd. The morphology of the block copolymer template is a horizontal columnar structure, and the morphology of the nanostructure of noble metals is a linear array; alternatively, the morphology of the block copolymer template is a vertical columnar structure, and the morphology of the nanostructure of noble metals is a lattice structure. The nanostructure of noble metals in this invention has an order degree ≥90%, a periodic fluctuation error ≤5%, and excellent adhesion to the substrate. The template morphology can be flexibly switched between linear and lattice structures by adjusting the solvent ratio. It is compatible with multiple noble metals, and the prepared metal structure has high purity and stable performance, and can be widely used in nanocircuits, sensors, surface-enhanced Raman spectroscopy substrates, and other fields.

Description

Technical Field

[0001] This invention belongs to the field of nanostructure technology, specifically relating to a nanostructure of noble metals, its preparation method and application. Background Technology

[0002] Nanoscale noble metal linear and dot arrays possess unique optoelectronic properties, making them irreplaceable in applications such as nanocircuits, sensors, and surface-enhanced Raman spectroscopy (SERS) substrates. Existing fabrication methods, such as electron beam lithography and nanoimprinting, suffer from problems such as expensive equipment, complex processes, and difficulties in large-scale production. In contrast, block copolymer directional self-assembly (DSA) technology, with its advantages of low cost, high order, and scalability, has become the preferred solution for preparing nanotemplates.

[0003] While existing technologies have explored the composite of block copolymer templates and metals, they suffer from bottlenecks such as uneven metal grafting, difficulty in achieving structural sizes exceeding 20 nm, and poor controllability in switching between linear and dot arrays. Furthermore, the lack of a clear correspondence between the DSA template morphology and the final metal structure limits their application in high-precision nanodevices. In addition, the bonding force between the metal and the template is weak in existing processes, leading to easy detachment, and the orderliness of the metal structure at the nanoscale is difficult to guarantee.

[0004] Therefore, the process for preparing nano-noble metal structures by combining block copolymer templates with metals still needs further improvement. Summary of the Invention

[0005] The purpose of this invention is to provide a nano-noble metal structure, its preparation method and application. The nano-noble metal structure has an order degree of ≥90%, a periodic fluctuation error of ≤5%, and excellent bonding force with the substrate.

[0006] To achieve the above objectives, a specific embodiment of the present invention provides the following technical solution:

[0007] A nanostructure of noble metal, comprising a block copolymer template and a noble metal loaded on the block copolymer template, wherein the block copolymer template is assembled from at least one of PS-P2VP and PS-P4VP, and the noble metal is at least one of Au, Ag, Pt, and Pd;

[0008] The block copolymer template has a flat columnar morphology, and the nano-noble metal structure has a linear array morphology.

[0009] Alternatively, the block copolymer template may have a vertical columnar morphology, and the nano-noble metal structure may have a lattice-like morphology.

[0010] In one or more embodiments of the present invention, the morphology of the nano-noble metal structure is a linear array with a linewidth of 10 nm-18 nm; or,

[0011] The morphology of the nano-noble metal structure is lattice-like, with a particle size of 10nm-18nm.

[0012] In one or more embodiments of the present invention, the degree of order of the nano-noble metal structure is ≥90%, and the periodic fluctuation error is ≤5%.

[0013] Another specific embodiment of the present invention provides the following technical solution:

[0014] A method for preparing a nanostructured noble metal, the method comprising the following steps:

[0015] Take a solvent and mix at least one of PS-P2VP and PS-P4VP with the solvent to obtain a mixed solution;

[0016] The mixed solution was coated onto a substrate and then annealed to obtain a block copolymer template.

[0017] The block copolymer template was placed in a noble metal salt solution, soaked, washed, and dried to obtain a block copolymer template adsorbed with noble metal ions.

[0018] The block copolymer template adsorbed with noble metal ions was reduced to obtain a nano-noble metal structure.

[0019] In one or more embodiments of the present invention, the solvent includes a first solvent and a second solvent in a volume ratio of 1:9 to 9:1, wherein the first solvent is at least one of toluene, styrene, chloroform, and tetrahydrofuran, and the second solvent is at least one of ethanol, methanol, N,N-dimethylformamide, and water.

[0020] In one or more embodiments of the present invention, the concentration of the mixed solution is 0.5wt%-3wt%; and / or,

[0021] The concentration of the noble metal salt solution is 0.01 mol / L to 0.1 mol / L; and / or,

[0022] The noble metal salt solution is an aqueous solution of at least one of HAuCl4, AgNO3, H2PtCl6, and PdCl2; and / or,

[0023] The number-average molecular weight of the PS-P2VP is 10kDa-80kDa, and the molar ratio of PS blocks to P2VP is 1:1-3:1; and / or,

[0024] The number-average molecular weight of the PS-P4VP is 10kDa-80kDa, and the molar ratio of PS blocks to P4VP is 1:1-3:1.

[0025] In one or more embodiments of the present invention, the mixed solution is spin-coated at a rotation speed of 2500 rpm to 5000 rpm, and the coating thickness is 50 nm to 180 nm; and / or,

[0026] The annealing treatment is carried out in a saturated vapor atmosphere of solvent at a temperature of 25℃-40℃ for 1h-4h; and / or,

[0027] In the soaking step, the soaking time is 2-6 hours, followed by rinsing with deionized water and drying with nitrogen gas; and / or,

[0028] After the reduction step is completed, oxygen plasma etching, toluene immersion for 10s-30s, or vacuum drying at 40℃-60℃ for 1h-2h are performed; wherein, the oxygen plasma etching conditions are: power 20w-200w, oxygen flow rate 10sccm-200sccm, time 1s-600s.

[0029] In one or more embodiments of the present invention, the reduction step employs chemical reduction, photoreduction, or plasma reduction.

[0030] In the chemical reduction method, the reducing agent used is sodium borohydride solution or ascorbic acid solution, with a concentration of 0.05 mol / L-0.2 mol / L, and the reduction is carried out at room temperature for 1-3 hours.

[0031] The photoreduction method uses ultraviolet light irradiation for reduction, with an irradiation time of 15-40 minutes.

[0032] The conditions for plasma reduction are as follows: first, oxygen treatment for 30-120 seconds, with an oxygen flow rate of 20-100 sccm, a power of 20-200 W, and a pressure of 10-120 Pa; then, hydrogen treatment for 30-120 seconds, with a hydrogen flow rate of 20-100 sccm, a power of 20-200 W, and a pressure of 10-120 Pa.

[0033] In one or more embodiments of the present invention, the substrate is a silicon wafer, a quartz wafer, or glass, and the substrate is pretreated using any of the following methods:

[0034] The sample was cleaned sequentially with acetone, ethanol, and deionized water, then dried with nitrogen, and finally subjected to oxygen plasma treatment. The oxygen plasma treatment conditions were: power 20w-200w, oxygen flow rate 10sccm-200sccm, and time 1s-600s.

[0035] The material is sequentially cleaned with acetone, ethanol, and deionized water, then dried with nitrogen, followed by oxygen plasma treatment, and finally coated with poly(styrene-r-2-vinylpyridine-r-hydroxyethyl methacrylate) with a thickness of 1nm-50nm. The oxygen plasma treatment conditions are: power 20W-200W, oxygen flow rate 10sccm-200sccm, and time 1s-600s.

[0036] Another specific embodiment of the present invention provides the following technical solution:

[0037] Applications of a nano-noble metal structure or a nano-noble metal structure prepared by the above-mentioned method in nanocircuits, sensors, and surface-enhanced Raman spectroscopy substrates.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] 1. Strong structural controllability and precise dimensions: By simply adjusting the shape of the DSA template (flat column / vertical column), the nano-noble metal linear array and dot array can be flexibly switched. The metal structure size can be controlled within the range of 10nm-18nm, meeting the requirements of high-precision nano-devices and solving the problem of complex structure switching in traditional processes.

[0040] 2. Strong metal bonding and high degree of order: Directional grafting is achieved by relying on the Lewis base coordination between the pyridine group and the noble metal ion, resulting in strong metal-template bonding and resistance to detachment; combined with the high order of the DSA template, the metal structure has an order of ≥90% and excellent periodicity.

[0041] 3. Simple and low-cost process, scalable: No expensive photolithography equipment is required. Metal grafting is achieved by adjusting the template through solvent ratio and coordination-reduction. The operation is simple and the process is short. It is suitable for large-area substrate processing and is easy to industrialize.

[0042] 4. Wide applicability and flexible adaptation of reduction processes: It is compatible with a variety of precious metals such as Au, Ag, Pt, and Pd, and can prepare nano-metal structures with different compositions; at the same time, it provides multiple solutions such as chemical reduction, photoreduction, and plasma reduction, which are adapted to the needs of large-scale mass production and high-precision cleanliness, further expanding the application range in multiple scenarios such as nano-circuits, SERS substrates, and nano-sensors.

[0043] 5. High structural purity and stable performance: Directional adsorption is achieved through coordination, reducing metal ion aggregation. Combined with targeted reduction processes, impurity residue can be effectively reduced, resulting in high metal structural purity. Vacuum drying and shaping further strengthen the bonding force, ensuring that the structure remains stable and does not fall off during subsequent processing and use, thus extending the service life of the device. Attached Figure Description

[0044] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0045] Figure 1 This is a flowchart of a method for preparing a nano-noble metal structure according to an embodiment of the present invention;

[0046] Figure 2 This is a SEM image of the nano-noble metal structure in Embodiment 1 of the present invention;

[0047] Figure 3 This is a SEM image of the nano-noble metal structure in Embodiment 2 of the present invention;

[0048] Figure 4 This is a SEM image of the nano-noble metal structure in Embodiment 3 of the present invention;

[0049] Figure 5 This is a SEM image of the nano-noble metal structure in Example 4 of the present invention. Detailed Implementation

[0050] To enable those skilled in the art to better understand the technical solutions in this disclosure, the technical solutions in the embodiments of this disclosure are described clearly and completely below. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments in this disclosure, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this disclosure.

[0051] One specific embodiment of the present invention provides a nanostructure of noble metal, comprising a block copolymer template and a noble metal loaded on the block copolymer template. The block copolymer template is assembled from at least one of PS-P2VP and PS-P4VP, and the noble metal is at least one of Au, Ag, Pt, and Pd. The morphology of the block copolymer template is a horizontal columnar structure, and the morphology of the nanostructure of noble metal is a linear array; or, the morphology of the block copolymer template is a vertical columnar structure, and the morphology of the nanostructure of noble metal is a lattice structure.

[0052] Specifically, in PS-P2VP and PS-P4VP block copolymers, the pyridine groups in the P2VP / P4VP blocks can act as Lewis bases, reacting with Au. 3+ Ag + Pt 4+ Pd 2+The formation of stable coordination bonds between noble metal ions provides a site basis for precise metal grafting.

[0053] This invention precisely prepares nano-noble metal linear arrays and lattices by adjusting the DSA assembly templates of PS-P2VP and PS-P4VP, thereby improving the orderliness, bonding force and size controllability of the metal structure and meeting the application requirements of high-precision nanodevices.

[0054] Furthermore, the morphology of the nano-noble metal structure is linear array with a linewidth of 10 nm to 18 nm; the morphology of the nano-noble metal structure is dot array with a dot size of 10 nm to 18 nm.

[0055] Furthermore, the degree of order of the nano-noble metal structure is ≥90%, and the periodic fluctuation error is ≤5%.

[0056] Another specific embodiment of the present invention provides a method for preparing nano-noble metal structures, such as... Figure 1 As shown, the specific steps include the following:

[0057] Step 1: Prepare block copolymer solution.

[0058] Specifically, PS-P2VP and PS-P4VP with a number average molecular weight of 10kDa-80kDa are selected. The molar ratio of PS blocks to P2VP in PS-P2VP is 1:1-3:1, and the molar ratio of PS blocks to P4VP in PS-P4VP is 1:1-3:1. The solvent includes a first solvent and a second solvent with a volume ratio of 1:9-9:1. The first solvent is at least one of toluene, styrene, chloroform, and tetrahydrofuran, and the second solvent is at least one of ethanol, methanol, N,N-dimethylformamide, and water. The volume ratio of the first solvent to the second solvent can specifically be 8:2-2:8, and exemplary ratios can be 5:5, 6:4, 7:3, 8:2, and 9:1. The PS-P2VP and PS-P4VP used in this invention are commercially available from manufacturers such as Aladdin, McLean, Sigma-Aldrich, Ron, Heinz, and Leyan.

[0059] Dissolve PS-P2VP or PS-P4VP in a solvent, ultrasonically disperse for 10-30 minutes, and allow to stand for 2-4 hours to degas, to obtain a homogeneous solution with a concentration of 0.5wt%-3wt%.

[0060] Step 2, substrate pretreatment.

[0061] Specifically, the substrate is a silicon wafer, quartz wafer, or glass. The substrate is ultrasonically cleaned sequentially with acetone, ethanol, and deionized water for 10-15 minutes, dried with nitrogen, and then treated with oxygen plasma (power 20W-200W, oxygen flow rate 10sccm-200sccm, time 1s-600s). Optionally, poly(r-2-vinylpyridine-r-hydroxyethyl methacrylate) is coated with a neutral brush (spin-coated at 6000rpm-10000rpm, thickness 1nm-50nm) to eliminate the specific interaction between the substrate and the blocks and ensure the orderliness of the template.

[0062] Step 3: Prepare the DSA template.

[0063] Specifically, the block copolymer solution is spin-coated onto the substrate at a speed of 2500 rpm to 5000 rpm to form a thin film with a thickness of 50 nm to 180 nm. Then, it is placed in a sealed device with solvent vapor of the same ratio as the solution, i.e., the saturated vapor of the solvent used to prepare the block copolymer solution, and annealed at 25℃ to 40℃ for 1 h to 4 h. The solvent is naturally removed to complete the self-assembly, and the block copolymer template, i.e., the DSA template, is obtained.

[0064] In this step, the morphology of the block copolymer template is controlled by adjusting the solvent assembly. When the volume ratio of the first solvent to the second solvent is 7:3 or 8:2, an ordered, flat-lying column template is formed. The columns are parallel to the substrate, with a width of 8 nm-18 nm and a spacing of 30 nm-50 nm between adjacent columns, providing guidance for the metal linear array. When the solvent is a single-component first solvent or the volume ratio of the first solvent to the second solvent is 5:5, 6:4, or 9:1, a vertical column template is formed. The columns are perpendicular to the substrate, with a diameter of 10 nm-18 nm and a spacing of 30 nm-50 nm, used for metal lattice positioning. The orderliness of both templates is ≥90%, and the periodic fluctuation error is ≤5%.

[0065] Step 4: Coordination grafting of noble metal ions.

[0066] The DSA template was immersed in an aqueous solution containing noble metal ions at room temperature for 2-6 hours. Utilizing the Lewis base properties of the pyridine groups in the P2VP / P4VP block, it reacted with Au... 3+ Ag + Pt 4+ Pd 2+ Stable coordination bonds are formed, allowing ions to be adsorbed uniformly and directionally onto the P2VP / P4VP phase. After soaking, uncoordinated free ions are rinsed with deionized water and dried with nitrogen to avoid the generation of impurity particles during the reduction process.

[0067] The aqueous solution containing noble metal ions is prepared by dissolving noble metal salts in water, with a concentration of 0.01 mol / L to 0.1 mol / L. The noble metal salts are HAuCl4, AgNO3, H2PtCl6, or PdCl2.

[0068] Step 5, reduce and cure.

[0069] Specifically, reduction methods include chemical reduction, photoreduction, or plasma reduction to suit different application requirements. Chemical reduction uses 0.05 mol / L-0.2 mol / L sodium borohydride or ascorbic acid aqueous solution, with reduction at room temperature for 1-3 hours. This method offers high efficiency, mild conditions, and is suitable for large-scale production. Photoreduction involves irradiation with ultraviolet ozone for 15-40 minutes. Plasma treatment involves first treating with oxygen for 30-120 seconds to solidify the shape, using an oxygen flow rate of 20-100 sccm, a power of 20-200 W, and a pressure of 10-120 Pa; then treating with hydrogen for 30-120 seconds for reduction, using a hydrogen flow rate of 20-100 sccm, a power of 20-200 W, and a pressure of 10-120 Pa. Both photoreduction and plasma reduction methods eliminate the need for chemical reagents, avoiding residues and meeting high-precision cleanliness requirements. Through reduction treatment, noble metal ions are reduced to elemental metals, forming a metal structure that matches the morphology of the template.

[0070] Step 6: Structural finalization.

[0071] Specifically, depending on the specific requirements, when an exposed metal structure is needed, oxygen plasma etching (power 20W-200W, oxygen flow rate 10sccm-200sccm, time 1s-600s) or immersion in toluene for 10s-30s is used to dissolve and remove the PS blocks. When a composite structure is required, vacuum drying at 40℃-60℃ for 1h-2h is performed directly to strengthen the adhesion between the metal and the substrate and prevent detachment.

[0072] This invention utilizes a horizontally lying column template with a column width of 8nm-18nm to prepare nanoscale metal linear arrays with a linewidth of 10nm-18nm; and utilizes a vertical column template with a diameter of 10nm-18nm to prepare nanoscale metal dot arrays with a particle size of 10nm-18nm. The periodic fluctuation error of both structures is ≤5%, and the degree of order is ≥90%.

[0073] Another specific embodiment of the present invention provides the application of a nano-noble metal structure or a nano-noble metal structure prepared by the above-described method in nanocircuits, sensors, and surface-enhanced Raman spectroscopy substrates.

[0074] The present invention will be further described in detail below with reference to specific embodiments. Unless otherwise specified, the reagents and instruments used in the present invention are all commercially available.

[0075] Example 1

[0076] The preparation method of the nano-noble metal structure in this embodiment is as follows:

[0077] 1. DSA flat column template preparation

[0078] A PS-P2VP block copolymer with a number average molecular weight of 50 kDa and a PS block to P2VP block molar ratio of 2:1 was selected and dissolved in a toluene-ethanol mixed solvent (toluene and ethanol volume ratio of 7:3) to prepare a block copolymer solution with a concentration of 2 wt%. The solution was ultrasonically dispersed for 20 min and allowed to stand for 3 h to remove bubbles.

[0079] A silicon wafer was selected as the substrate and ultrasonically cleaned with acetone, ethanol and deionized water for 15 min in sequence. After being dried with nitrogen, it was treated with oxygen plasma for 8 min (power 100 W, oxygen flow rate 100 sccm). A poly(styrene-r-2-vinylpyridine-r-hydroxyethyl methacrylate) neutral brush was then coated with the coating, with a thickness of 20 nm.

[0080] The block copolymer solution was spin-coated onto the surface of a pretreated silicon wafer at 3000 rpm for 45 s to form a 100 nm thick film. The spin-coated silicon wafer was then placed in a sealed device, and toluene-ethanol mixed solvent (volume ratio 7:3) vapor was introduced. The wafer was annealed at 30 °C for 2 h to obtain a flat-lying column template with a column width of 15 nm, a column spacing of 40 nm, and an order degree of 92%.

[0081] 2. Silver ion coordination grafting

[0082] The above-mentioned flat-lying column template was immersed in a 0.05 mol / L AgNO3 aqueous solution and soaked at room temperature for 4 hours to allow the pyridine groups to react with AgNO3. + Forming stable coordination bonds, Ag + The Ag is uniformly adsorbed onto the P2VP phase region of the template. After soaking, the template surface is repeatedly rinsed with deionized water and dried with nitrogen to remove free Ag. + .

[0083] 3. Restoration and Post-processing

[0084] A chemical reduction method was selected (to meet the needs of large-scale preparation). The template was immersed in a 0.1 mol / L ascorbic acid aqueous solution and slowly reduced by stirring at room temperature for 2 hours, allowing the Ag to be coordinated and adsorbed. + It is completely reduced to elemental Ag. Then, it is soaked in toluene for 20 seconds to dissolve and remove the PS blocks, and then vacuum dried at 60°C for 1.5 hours to fix it and strengthen the adhesion between the silver wire and the substrate.

[0085] Characterized by SEM (e.g.) Figure 2The silver wire array has a linewidth of 15 nm, which is a typical nanostructure. The silver wires are arranged in a hexagonal order along the template guide, with an order degree of 91%. When the obtained nano-noble metal structure is directly pulled using blue film release tape or PMMA photoresist, the silver wires cannot be peeled off, demonstrating excellent adhesion to the silicon substrate and no detachment.

[0086] Example 2

[0087] The preparation method of the nano-noble metal structure in this embodiment is as follows:

[0088] 1. DSA flat column template preparation

[0089] PS-P4VP (number average molecular weight 40 kDa, molar ratio of PS block to P4VP block 1.5:1) was selected, dissolved in a toluene-ethanol mixed solvent (toluene and ethanol volume ratio 8:2), and a block copolymer solution with a concentration of 1.5 wt% was prepared. After sonication for 15 min, the solution was allowed to stand for degassing for 2.5 h.

[0090] Take a quartz plate and ultrasonically clean it sequentially with acetone, ethanol and deionized water for 15 minutes. After drying with nitrogen, treat it with oxygen plasma for 6 minutes (power 100w, oxygen flow rate 100sccm).

[0091] The block copolymer solution was spin-coated onto a quartz sheet at 4000 rpm for 30 s to form an 80 nm thick film. Then, toluene-ethanol mixed solvent (volume ratio 8:2) vapor was introduced and annealed at 35 °C for 3 h to obtain a flat column template with a column width of 12 nm, a spacing of 35 nm, and an order degree of 91%.

[0092] 2. Gold ion coordination grafting

[0093] The above-mentioned flat column template was immersed in a 0.03 mol / L HAuCl4 aqueous solution for 3 hours at room temperature, rinsed with deionized water, and dried with nitrogen gas to allow the pyridine groups to react with Au. 3+ Directed coordination adsorption.

[0094] 3. Restoration and Post-processing

[0095] Because the preparation of SERS substrates requires high structural cleanliness, the photoreduction method was selected, using 254nm ultraviolet light irradiation for 30 minutes to reduce Au content. 3+ Completely reduced to elemental Au, with no chemical reagent residue. Subsequently, oxygen plasma etching (power 150W, oxygen flow rate 150sccm, etching time 200s) was used to remove PS blocks, followed by vacuum drying at 50℃ for 2 hours for shaping.

[0096] SEM characterization shows (e.g.) Figure 3 The gold line is 12nm wide, with an ordered linear array distribution, a periodic fluctuation error of 4%, and high purity, making it suitable for SERS detection requirements.

[0097] Example 3

[0098] The preparation method of the nano-noble metal structure in this embodiment is as follows:

[0099] 1. DSA Vertical Column Template Preparation

[0100] A PS-P2VP block copolymer with a number-average molecular weight of 60 kDa and a PS block to P2VP block molar ratio of 2.5:1 was selected and dissolved in a single-component toluene solvent to prepare a 3 wt% block copolymer solution. The solution was ultrasonically dispersed for 25 min and allowed to stand for degassing for 4 h.

[0101] Silicon wafers were selected as the substrate and ultrasonically cleaned sequentially with acetone, ethanol, and deionized water for 15 minutes. After being dried with nitrogen, they were treated with oxygen plasma for 10 minutes (power 100W, oxygen flow rate 100sccm).

[0102] The block copolymer solution was spin-coated onto the surface of a pretreated silicon wafer at 2500 rpm for 50 s to form a thin film with a thickness of 120 nm. The spin-coated silicon wafer was placed in a sealed device, toluene vapor was introduced, and the wafer was annealed with solvent vapor at 28 °C for 2.5 h to obtain a vertical column template with a column diameter of 16 nm, a column spacing of 38 nm, and an order degree of 93%.

[0103] 2. Platinum ion coordination grafting

[0104] The above-mentioned vertical column template was immersed in a 0.08 mol / L H2PtCl6 aqueous solution for 5 hours at room temperature, allowing the pyridine groups to react with the Pt group. 4+ Forming stable coordination bonds, Pt 4+ The P2VP phase region of the template is uniformly adsorbed; after soaking, the template surface is repeatedly rinsed with deionized water and dried with nitrogen to remove free Pt. 4+ .

[0105] 3. Restoration and Post-processing

[0106] The sodium borohydride chemical reduction method was selected (high reduction efficiency, suitable for batch preparation of nanosensor electrodes). The template was immersed in a 0.15 mol / L sodium borohydride aqueous solution and reduced at room temperature for 1.5 h to ensure Pt 4+ Complete reduction. Then soak in toluene for 20 seconds to dissolve and remove the PS blocks, and vacuum dry at 55°C for 1 hour to set.

[0107] SEM characterization shows (e.g.) Figure 4 The platinum lattice particles have a diameter of 16 nm, are periodically arrayed, and have excellent bonding strength, making them stable for use as sensor electrodes.

[0108] Example 4

[0109] The preparation method of the nano-noble metal structure in this embodiment is as follows:

[0110] 1. DSA Vertical Column Template Preparation

[0111] PS-P4VP (number average molecular weight of 30 kDa, molar ratio of PS block to P4VP block of 1:1) was selected, dissolved in toluene-ethanol mixed solvent (toluene to ethanol volume ratio of 6:4), and a block copolymer solution with a concentration of 2.5 wt% was prepared. After sonication for 20 min, the solution was allowed to stand for 3 h to degas.

[0112] The glass substrate was ultrasonically cleaned with acetone, ethanol and deionized water for 15 minutes in sequence, dried with nitrogen and then treated with oxygen plasma for 7 minutes (power 90w, oxygen flow rate 90sccm).

[0113] The block copolymer solution was spin-coated onto a glass substrate at 3500 rpm for 40 s to form a 90 nm thick film. Then, toluene-ethanol mixed solvent (volume ratio 6:4) vapor was introduced and annealed at 32 °C for 1.5 h to obtain a vertical column template with a column diameter of 10 nm, a spacing of 30 nm, and an order degree of 92%.

[0114] 2. Palladium ion coordination grafting

[0115] The template was immersed in a 0.06 mol / L PdCl2 aqueous solution for 3.5 h at room temperature, rinsed with deionized water, and dried under nitrogen. The pyridine groups and Pd... 2+ Complete directional coordination adsorption.

[0116] 3. Restoration and Post-processing

[0117] The ascorbic acid chemical reduction method (mild conditions, avoiding metal particle agglomeration) was selected. The template was immersed in 0.1 mol / L ascorbic acid aqueous solution and reduced at room temperature for 2 hours. Then, oxygen plasma etching (power 100 W, oxygen flow rate 100 sccm, etching time 300 s) was performed to remove PS blocks, and the template was vacuum dried at 50℃ for 1.5 hours for shaping.

[0118] SEM characterization shows (e.g.) Figure 5 The palladium lattice has a particle size of 10 nm, which is a typical nanostructure with good periodicity, and can be used stably as a nano-circuit interconnect node.

[0119] It will be apparent to those skilled in the art that this disclosure is not limited to the details of the exemplary embodiments described above, and that this disclosure can be implemented in other specific forms without departing from the spirit or essential characteristics of this disclosure. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of this disclosure is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this disclosure.

[0120] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A nanostructure of noble metals, characterized in that, The nano-noble metal structure includes a block copolymer template and a noble metal loaded on the block copolymer template. The block copolymer template is assembled from at least one of PS-P2VP and PS-P4VP, and the noble metal is at least one of Au, Ag, Pt, and Pd. The block copolymer template has a flat columnar morphology, and the nano-noble metal structure has a linear array morphology. Alternatively, the block copolymer template may have a vertical columnar morphology, and the nano-noble metal structure may have a lattice-like morphology.

2. The nanostructure of noble metals according to claim 1, characterized in that, The morphology of the nano-noble metal structure is linear array-like, with a linewidth of 10 nm-18 nm; or, The morphology of the nano-noble metal structure is lattice-like, with a particle size of 10nm-18nm.

3. The nanostructure of noble metals according to claim 1, characterized in that, The degree of order of the nano-noble metal structure is ≥90%, and the periodic fluctuation error is ≤5%.

4. A method for preparing the nano-noble metal structure according to claim 1, characterized in that, The preparation method includes the following steps: Take a solvent and mix at least one of PS-P2VP and PS-P4VP with the solvent to obtain a mixed solution; The mixed solution was coated onto a substrate and then annealed to obtain a block copolymer template. The block copolymer template was placed in a noble metal salt solution, soaked, washed, and dried to obtain a block copolymer template adsorbed with noble metal ions. The block copolymer template adsorbed with noble metal ions was reduced to obtain a nano-noble metal structure.

5. The method for preparing nano-noble metal structures according to claim 4, characterized in that, The solvent includes a first solvent and a second solvent in a volume ratio of 1:9 to 9:1, wherein the first solvent is at least one of toluene, styrene, chloroform, and tetrahydrofuran, and the second solvent is at least one of ethanol, methanol, N,N-dimethylformamide, and water.

6. The method for preparing nano-noble metal structures according to claim 4, characterized in that, The concentration of the mixed solution is 0.5wt%-3wt%; and / or, The concentration of the noble metal salt solution is 0.01 mol / L to 0.1 mol / L; and / or, The noble metal salt solution is an aqueous solution of at least one of HAuCl4, AgNO3, H2PtCl6, and PdCl2; and / or, The number-average molecular weight of the PS-P2VP is 10kDa-80kDa, and the molar ratio of PS blocks to P2VP is 1:1-3:1; and / or, The number-average molecular weight of the PS-P4VP is 10kDa-80kDa, and the molar ratio of PS blocks to P4VP is 1:1-3:

1.

7. The method for preparing nano-noble metal structures according to claim 4, characterized in that, The mixed solution is spin-coated at a speed of 2500 rpm-5000 rpm to achieve a coating thickness of 50 nm-180 nm; and / or, The annealing treatment is carried out in a saturated vapor atmosphere of solvent at a temperature of 25℃-40℃ for 1h-4h; and / or, In the soaking step, the soaking time is 2-6 hours, followed by rinsing with deionized water and drying with nitrogen gas; and / or, After the reduction step is completed, oxygen plasma etching, toluene immersion for 10s-30s, or vacuum drying at 40℃-60℃ for 1h-2h are performed; wherein, the oxygen plasma etching conditions are: power 20w-200w, oxygen flow rate 10sccm-200sccm, time 1s-600s.

8. The method for preparing nano-noble metal structures according to claim 4, characterized in that, The reduction step employs chemical reduction, photoreduction, or plasma reduction. In the chemical reduction method, the reducing agent used is sodium borohydride solution or ascorbic acid solution, with a concentration of 0.05 mol / L-0.2 mol / L, and the reduction is carried out at room temperature for 1-3 hours. The photoreduction method uses ultraviolet light irradiation for reduction, with an irradiation time of 15-40 minutes. The conditions for plasma reduction are as follows: first, oxygen treatment for 30-120 seconds, with an oxygen flow rate of 20-100 sccm, a power of 20-200 W, and a pressure of 10-120 Pa; then, hydrogen treatment for 30-120 seconds, with a hydrogen flow rate of 20-100 sccm, a power of 20-200 W, and a pressure of 10-120 Pa.

9. The method for preparing nano-noble metal structures according to claim 4, characterized in that, The substrate is a silicon wafer, a quartz wafer, or glass, and the substrate is pretreated using any of the following methods: The sample was cleaned sequentially with acetone, ethanol, and deionized water, then dried with nitrogen, and finally subjected to oxygen plasma treatment. The oxygen plasma treatment conditions were: power 20w-200w, oxygen flow rate 10sccm-200sccm, and time 1s-600s. The material is sequentially cleaned with acetone, ethanol, and deionized water, then dried with nitrogen, followed by oxygen plasma treatment, and finally coated with poly(styrene-r-2-vinylpyridine-r-hydroxyethyl methacrylate) with a thickness of 1nm-50nm. The oxygen plasma treatment conditions are: power 20W-200W, oxygen flow rate 10sccm-200sccm, and time 1s-600s.

10. The application of a nano-noble metal structure according to any one of claims 1-3 or a nano-noble metal structure prepared by the preparation method of the nano-noble metal structure according to any one of claims 4-9 in nanocircuits, sensors, and surface-enhanced Raman spectroscopy substrates.

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