Metal single crystal substrate with surface having hatp-cu network and preparation method and application thereof

Abstract

This application relates to the field of surface chemistry and the controllable preparation technology of two-dimensional metal-organic networks, specifically to a metal single-crystal substrate with an HATP-Cu network on its surface, its preparation method, and its applications. The HATP-Cu two-dimensional network is constructed on the surface of the metal single-crystal substrate, and includes HATP ligand molecules and copper metal coordination nodes. The copper metal coordination nodes are arranged in a predetermined periodic pattern at the connection sites between adjacent HATP ligands, forming a continuous HATP-Cu network on the surface of the metal single-crystal substrate. This HATP-Cu network has a large lateral size, good continuity, and stable two-dimensional periodic arrangement, and exhibits high thermal stability, maintaining a basically intact two-dimensional ordered structure even under high-temperature processing conditions.

Description

Technical Field

[0001] This invention relates to the field of surface chemistry and controllable preparation technology of two-dimensional metal-organic networks, specifically to a metal single crystal substrate with a surface HATP (2,3,6,7,10,11-hexaaminotriphenyl)-Cu network, its preparation method, and its application. Background Technology

[0002] Two-dimensional metal-organic networks (2D-MONs) are important model systems for studying surface confined coordination assembly, interfacial reaction processes, and intermolecular interactions. Existing research shows that the formation of surface 2D-MONs is influenced by multiple factors, including precursor configuration, metal nodes, lattice matching, and external atmosphere. Within the same system, different network structures often exhibit competition, selection, and transformation relationships, making network structure controllability a key challenge in fabrication. Current methods for constructing surface 2D-MONs mainly rely on precursor molecule deposition, metal atom participation, and annealing induction. However, several technical bottlenecks remain in practical applications: insufficient network structure selectivity, difficulty in achieving large-area growth of target structures, numerous defects, and limited thermal stability. Due to the high coupling between precursor activation, metal node participation, and network evolution, existing fabrication routes struggle to achieve precise decoupling and independent control of each step. Specifically, three typical routes commonly found in existing technologies are as follows: Route 1 involves direct deposition of the precursor followed by annealing. This preparation route is simple, but it is difficult to precisely control the degree of amino activation. For example, in the HATP / Cu(111) system reported in the literature (DOI:10.1002 / chem.201803908), van der Waals and coordination structures coexist at 100℃, while topologically diverse coordination networks are formed at 200℃, showing problems of poor structural selectivity and high diversity.

[0003] Route two involves adjusting parameters such as coverage and temperature. This preparation route allows for adjustment of the network structure within a certain range, but it is difficult to simultaneously achieve both structural selectivity and integrity. For example, the literature (DOI:10.1039 / D3CC00185G) shows that different networks can be obtained simply by changing the deposition and heating methods; the literature (DOI:10.1002 / chem.201803908) shows that low coverage leads to the coexistence of multiple structures, while high coverage induces clustering. This indicates that relying solely on traditional process parameters often fails to achieve the simultaneous acquisition of high selectivity and large-area, low-defect networks.

[0004] Route 3 involves co-deposition of the precursor and exogenous metal followed by heat treatment. While this can form a coordination network, the resulting network area is small, and it contains a significant amount of unreacted precursor and exogenous metal, making it difficult to obtain a large-area, low-defect network.

[0005] Furthermore, in the aforementioned typical routes, oxygen is considered a background factor that triggers side reactions and is not used as an active process control variable. Those skilled in the art would not naturally combine "oxygen-induced construction of HATP-Ag template networks" with "copper substitution to convert to HATP-Cu networks" as a continuous process route.

[0006] Therefore, there is a need to provide a surface two-dimensional metal-organic network that can simultaneously achieve structural controllability and high thermal stability, as well as a method for its preparation. Summary of the Invention

[0007] The purpose of this invention is to provide a metal single crystal substrate with an HATP-Cu network on its surface and a method for preparing the same. By causing Cu metal coordination nodes to be distributed at the connection sites of adjacent HATP ligands, a HATP-Cu network structure with controllable structure is formed on the surface of the metal single crystal substrate. The HATP-Cu network has a large lateral size, good continuity and high thermal stability.

[0008] To achieve the above objectives, the present invention provides the following technical solution: a metal single-crystal substrate with an HATP-Cu network on its surface, comprising: Metal single crystal substrate; An HATP-Cu network is constructed on the surface of the metal single crystal substrate. The HATP-Cu network includes HATP ligands and copper metal coordination nodes. Adjacent HATP ligands are coordinated and connected through the copper metal coordination nodes. The copper metal coordination nodes are arranged in a preset periodic pattern at the connection positions between adjacent HATP ligands, so that the HATP ligands and the copper metal coordination nodes form a continuous HATP-Cu network on the surface of the metal single crystal substrate.

[0009] Furthermore, the HATP-Cu network exhibits a two-dimensional periodic coordination structure, and the HATP-Cu network maintains its two-dimensional periodic coordination structure even under heat treatment conditions of 320℃-370℃. The lateral dimension of the HATP-Cu network is not less than 50 nm.

[0010] Furthermore, the metal single crystal substrate is an Ag(111) single crystal substrate.

[0011] This application provides a method for preparing a metal single-crystal substrate with an HATP-Cu network on its surface, comprising the following steps: S1. Obtain a metal single crystal substrate and pre-treat the metal single crystal substrate. The pre-treatment includes surface cleaning of the metal single crystal substrate to remove contaminants on the surface of the metal single crystal substrate and obtain an atomically flat metal single crystal surface. S2. Under ultra-high vacuum conditions, HATP ligand molecules are deposited on the surface of the pretreated metal single crystal substrate, so that the HATP ligand molecules are adsorbed on the surface of the metal single crystal substrate according to a preset coverage. S3. Expose the metal single crystal substrate with HATP ligand molecules adsorbed on its surface to an oxygen atmosphere, so that the HATP ligand molecules and the metal single crystal substrate undergo an interfacial coordination reaction, promoting the formation of metal coordination nodes between adjacent HATP ligand molecules, and forming a continuous HATP-metal template network with a periodic network structure. S4. Deposit copper atoms on the surface of the HATP-metal template network, so that the copper atoms are distributed near the metal coordination nodes of the HATP-metal template network; S5. Anneal the HATP-metal template network on which the copper atoms are deposited, so that the copper atoms migrate to the surface during the annealing process and replace the original metal coordination nodes in the HATP-metal template network, and re-coordinate with the HATP ligand molecules to form copper metal coordination nodes, thereby causing the coordination nodes of the HATP-metal template network to be reconstructed, and a metal single crystal substrate with an HATP-Cu network on the surface is obtained.

[0012] Further, in step S5, the copper metal coordination node is formed by the copper atom coordinating with the nitrogen atom in the adjacent HATP ligand molecule to connect the adjacent HATP ligand molecule, and replacing the original metal coordination node in the HATP-metal template network.

[0013] Furthermore, in step S2, the preset coverage is a sub-monolayer. In step S3, the oxygen is introduced into the oxygen atmosphere either continuously or in stages.

[0014] Furthermore, in step S3, the structure of the HATP-metal template network is adjusted by regulating the oxygen concentration or the exposure time and number of times the metal single crystal substrate is exposed to an oxygen atmosphere; The oxygen concentration is 1×10⁻⁶ -9 mbar~1×10 -5 Any value in mbar; The exposure duration is any value between 3 min and 15 min; The number of exposures is 1 to 3 times.

[0015] Furthermore, the HATP-metal template network includes: an HATP-Ag template network formed on the surface of an Ag(111) single crystal substrate; the HATP-Ag template network has a two-dimensional periodic network structure; The HATP-Ag template network is any one or more of the HATP-Ag-α template network, HATP-Ag-β template network, and HATP-Ag-γ template network.

[0016] Further, in step S4, the copper atoms are deposited on the surface of the HATP-metal template network by thermal evaporation, electron beam evaporation or molecular beam epitaxy; In step S5, the annealing temperature is 200℃~400℃.

[0017] This application also provides the application of the above-mentioned metal single crystal substrate with HATP-Cu network on the surface in the preparation of two-dimensional electronic devices, molecular sensors, catalytic materials, and surface reaction template materials.

[0018] The beneficial effects of the present invention are as follows: The metal single crystal substrate with HATP-Cu network on the surface provided by this application, by causing Cu metal coordination nodes to be distributed at the connection positions of adjacent HATP ligands, constructs a periodically coordinated and ordered two-dimensional HATP-Cu network structure on the surface of the metal single crystal substrate. The resulting HATP-Cu network has a large lateral size, good continuity and stable two-dimensional periodic arrangement characteristics, and exhibits high thermal stability. It can still maintain a basically complete two-dimensional ordered structure under high temperature processing conditions.

[0019] This application provides a method for preparing a metal single-crystal substrate with an HATP-Cu network on its surface. This method employs a sequential approach, including oxygen-induced construction of an HATP-metal template network and copper substitution to form the HATP-Cu network. This decouples the precursor alignment process from the metal node regulation process, resulting in a controllable structure, large area, fewer defects, and high thermal stability in the HATP-Cu two-dimensional metal-organic network. Specifically, this method utilizes oxygen as an actively controlled process variable. By exposing a metal single-crystal substrate with HATP molecules adsorbed on its surface to an oxygen atmosphere, HATP molecules undergo coordination reactions with the surface atoms of the metal single-crystal substrate, forming a periodic HATP-metal template network. A copper substitution reaction is then performed to prepare the HATP-Cu two-dimensional metal-organic network structure. This template-guided substitution path effectively avoids the reaction path competition problem caused by the simultaneous occurrence of precursor activation, metal coordination, and network self-assembly processes in existing technologies, thereby improving the controllability of the structure formation process and the selectivity of the network structure.

[0020] Since the copper substitution process is based on an existing two-dimensional ordered network structure, compared to the method of directly depositing HATP molecules and copper atoms followed by annealing to form an HATP-Cu network, the preparation method provided in this application can reduce the random diffusion and disordered clustering of unreacted HATP molecules and copper atoms, resulting in a HATP-Cu network with a larger coverage area and lower structural defects, thus improving the integrity of the network structure. Furthermore, this preparation method is applicable to different types of HATP-metal template networks as precursor structures, demonstrating good applicability and scalability.

[0021] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0022] Figure 1 This is a scanning tunneling microscope (STM) image of an Ag(111) single crystal substrate exposed to an oxygen atmosphere, as shown in Example 1 of this invention. Figure 2 This is an STM scan of the Au(111) single crystal substrate of Comparative Example 1 of the present invention after being exposed to an oxygen atmosphere; Figure 3 This is an STM scan of the Ag(111) single crystal substrate after being exposed to oxygen atmospheres with different oxygen partial pressures, as shown in Example 2 of the present invention. Figure 4 This is an STM image of the Ag(111) single crystal substrate that has been exposed to an oxygen atmosphere again, as shown in Example 3 of this invention. Figure 5 This is an STM image of an Ag(111) single crystal substrate with an HATP-Cu network structure formed on its surface, as shown in Example 4 of this invention. Figure 6 This is an STM image of the Ag(111) single crystal substrate with an HATP-Cu network structure formed on its surface, as shown in Comparative Example 2 of the present invention. Figure 7 The image shows the STM plot of the thermal stability test results of the Ag(111) single crystal substrate with an HATP-Cu network structure formed on its surface, as shown in Example 4 of this invention. Detailed Implementation

[0023] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0025] A preferred embodiment of this application discloses a metal single-crystal substrate with an HATP-Cu network on its surface, comprising a metal single-crystal substrate and an HATP-Cu network, wherein the HATP-Cu network is constructed on the surface of the metal single-crystal substrate. The HATP-Cu network includes HATP ligands and copper metal coordination nodes. The copper metal coordination nodes are arranged in a predetermined periodic pattern at the connection sites between adjacent HATP ligands, allowing adjacent HATP ligands to be coordinated and connected through the copper metal coordination nodes, thereby forming a continuous and periodic two-dimensional network structure, i.e., the HATP-Cu network, on the surface of the metal single-crystal substrate. Because the Cu metal coordination nodes are confined to the connection sites of the organic ligands, this HATP-Cu two-dimensional metal-organic network possesses a well-defined periodic coordination structure and a continuous two-dimensional topology. This avoids the structural competition problem caused by the high coupling of precursor molecule adsorption, metal participation, and network formation process in traditional direct annealing methods, and overcomes the defects of random distribution of coordination nodes and coexistence of multiple topologies, achieving deterministic control and highly consistent construction of the two-dimensional metal-organic network structure. In this embodiment or other embodiments, copper metal coordination nodes form coordination bonds between copper atoms and nitrogen atoms in adjacent HATP ligand molecules, thereby connecting adjacent HATP ligand molecules through the copper metal coordination nodes and forming a continuous two-dimensional coordination network on the surface of the metal single-crystal substrate. The copper metal coordination nodes serve both as coordination connection sites between adjacent HATP ligands and as periodic metal nodes in the two-dimensional network structure, maintaining the continuity and order of the HATP-Cu network.

[0026] In one embodiment, the HATP-Cu network possesses a periodic coordination structure, and this HATP-Cu network retains its periodic coordination structure even under heat treatment conditions of 320℃-370℃. That is, this HATP-Cu network significantly outperforms networks prepared by direct annealing methods in terms of structural integrity and thermal stability, maintaining a stable two-dimensional periodic structure even at temperatures of 320℃-370℃. Furthermore, as... Figure 5 As shown, the lateral dimension of the HATP-Cu network is not less than 50 nm; that is, the lateral dimension of the continuous region of the HATP-Cu network is ≥50 nm, and can even reach hundreds of nanometers.

[0027] In one embodiment, the metal single crystal substrate is selected from Ag(111) single crystal substrates. Under oxygen treatment conditions, the Ag(111) surface can effectively induce HATP molecules to undergo dehydrogenation activation and form an ordered HATP-Ag template network, thereby providing a structured precursor framework for subsequent copper replacement.

[0028] One embodiment provides a method for preparing a metal single-crystal substrate with an HATP-Cu network on its surface, comprising the following steps: S1. Obtain a metal single crystal substrate and pre-treat the metal single crystal substrate. The pre-treatment includes surface cleaning of the metal single crystal substrate to remove contaminants on the surface of the metal single crystal substrate and obtain an atomically flat metal single crystal surface. S2. Under ultra-high vacuum conditions, HATP ligand molecules are deposited on the surface of the pretreated metal single crystal substrate, so that the HATP ligand molecules are adsorbed on the surface of the metal single crystal substrate according to the preset coverage. S3. Expose the metal single crystal substrate with HATP ligand molecules adsorbed on its surface to an oxygen atmosphere, so that the HATP ligand molecules and the metal single crystal substrate undergo an interfacial coordination reaction, promoting the formation of metal coordination nodes between adjacent HATP ligand molecules, and forming a continuous HATP-metal template network with a periodic network structure. S4. Deposit copper atoms on the surface of the HATP-metal template network so that the copper atoms are distributed near the metal coordination nodes of the HATP-metal template network; S5. Annealing is performed on the HATP-metal template network with deposited copper atoms, which causes the copper atoms to migrate to the surface during the annealing process and replace the original metal coordination nodes in the HATP-metal template network. The copper atoms then re-coordinate with the HATP ligand molecules to form copper metal coordination nodes, thereby causing the coordination nodes of the HATP-metal template network to be reconstructed, resulting in a metal single crystal substrate with an HATP-Cu network on the surface.

[0029] This preparation method employs a two-step process route of "oxygen-induced template network construction - copper replacement," rather than the one-step route of direct co-annealing of HATP and copper atoms in existing technologies. This allows HATP molecules to first undergo dehydrogenation activation under the influence of oxygen, forming an ordered HATP-metal template network, followed by coordination node reconstruction through copper replacement. This ensures that the resulting HATP-Cu network exhibits significantly superior structural integrity and thermal stability compared to networks prepared by direct annealing methods. It maintains a stable two-dimensional periodic structure at 320℃-370℃, with lateral dimensions exceeding 50 nm, and even reaching hundreds of nanometers. This achieves the synergistic acquisition of a controllable template network structure, tunable coordination centers, and a highly thermally stable two-dimensional HATP-Cu network, avoiding the structural competition and randomness issues caused by the high coupling of precursor activation, metal participation, and network formation processes in the direct annealing route. Therefore, it significantly improves the controllability and consistency of the network structure.

[0030] In one embodiment, in step S5, the copper metal coordination node is formed by the coordination bonding between a copper atom and the nitrogen atom in the adjacent HATP ligand molecule, connecting the adjacent HATP ligand molecule and replacing the original metal coordination node in the HATP-metal template network.

[0031] In one embodiment, in step S2, the preset coverage is preferably sub-monolayer, and more preferably, the HATP coverage is limited to the range of 0.2 monolayers to 1 monolayer. When the HATP coverage is less than 0.2 monolayers, the intermolecular spacing on the surface is too large, making it difficult for molecules to interact effectively and form an interface, which is not conducive to the formation of a continuous two-dimensional network structure. When the coverage is greater than 1 monolayer, molecules are prone to multilayer stacking and local clustering on the surface, resulting in disordered adsorption configuration, which in turn reduces the uniformity and integrity of the subsequent template network formation. Limiting the HATP coverage to the range of 0.2 monolayers to 1 monolayer allows HATP molecules to be uniformly adsorbed on the surface of single crystals such as Ag(111) in a monolayer or sub-monolayer form, forming an ordered precursor layer structure, providing a uniform and stable initial structural basis for the subsequent oxygen-induced interfacial coordination reaction, thereby effectively reducing network defects and improving the consistency of template network formation.

[0032] In one embodiment, oxygen is introduced into the oxygen atmosphere either continuously or in stages. The staged oxygen introduction method allows for step-by-step control of the dehydrogenation activation process of HATP molecules, progressively advancing the interfacial reaction and thus improving the structural selectivity of the HATP-metal template network formation. It also promotes, to some extent, the controllable transformation between different template networks. The continuous oxygen introduction method, on the other hand, has a simpler process path, reducing operational complexity and improving experimental reproducibility. In this embodiment or other embodiments, the structure of the HATP-metal template network can be adjusted by regulating the oxygen concentration or the exposure time and number of exposures of the metal single-crystal substrate in the oxygen atmosphere. The oxygen concentration, exposure time, and number of exposures directly affect the degree of dehydrogenation activation of the amino groups in the HATP molecules and their coordination behavior on the metal single-crystal surface. By adjusting these parameters, any one of the following structures—HATP-Ag-α template network, HATP-Ag-β template network, or HATP-Ag-γ template network—can be selectively formed, and under specific conditions, directional transformation between different template networks can be induced. This allows oxygen to function not merely as a reaction environment factor, but as a key process variable for precisely controlling the degree of molecular activation and the evolution of the template network structure, thereby enabling the controllable construction of the template network structure type and its transformation pathway. In some embodiments, the oxygen concentration is preferably 1 × 10⁻⁶. -9 mbar~1×10 -5 Any value in mbar. Exposure duration any value between 3 min and 15 min. Number of exposures between 1 and 3.

[0033] In one embodiment, the HATP-metal template network is an HATP-Ag template network formed on the surface of an Ag(111) single-crystal substrate. This HATP-Ag template network exhibits a two-dimensional periodic network structure. In this embodiment or other embodiments, HATP-Ag template networks with different periodic arrangement characteristics can be obtained by changing the oxygen treatment conditions. For ease of distinction, the three different periodic HATP-Ag template networks observed in this application are respectively designated as HATP-Ag-α template network, HATP-Ag-β template network, and HATP-Ag-γ template network. The three template networks exhibit different periodic arrangement characteristics in STM characterization and can all serve as precursor templates for subsequent copper atom participation in metal coordination node reconstruction. Furthermore, although these three HATP-Ag template networks differ in structural morphology and amino activation levels, they can all be transformed into the same HATP-Cu two-dimensional metal-organic network during subsequent copper replacement processes. This also demonstrates that the preparation method has good process tolerance and structural adaptability to the initial template structure. It not only reduces the requirements for precise control of a single template network, but also improves the robustness, repeatability and operability of the entire preparation process, thereby enhancing the applicability and process universality of the method under different experimental conditions.

[0034] In one embodiment, in step S4, copper atoms are deposited on the surface of the HATP-metal template network via thermal evaporation, electron beam evaporation, or molecular beam epitaxy. The various deposition methods for copper atoms can be selected according to the conditions of different surface science experimental equipment, thus giving the preparation method good equipment adaptability and process compatibility. In this embodiment or other embodiments, in step S5, the annealing temperature is preferably 200℃~400℃. Setting the annealing temperature in the range of 200℃~400℃ is based on a balance between the copper substitution reaction kinetics and the stability of the template network. This ensures that the copper substitution reaction proceeds fully while maintaining the structural order of the template network, thereby obtaining an HATP-Cu two-dimensional metal-organic network with high structural integrity and good continuity.

[0035] One embodiment provides the application of the aforementioned metal single-crystal substrate with an HATP-Cu network on its surface in the fabrication of two-dimensional electronic devices, molecular sensors, catalytic materials, surface reaction template materials, or separation membrane materials. Because the HATP-Cu network on the surface of this metal single-crystal substrate possesses characteristics of large area, high thermal stability, and high structural integrity, it overcomes the bottlenecks of existing networks that are small in area, have many defects, and poor thermal stability, making them difficult to apply in practical scenarios. It demonstrates feasibility for application in functional layers of electronic devices, catalytic active layers, and molecular detection sensors, expanding the path from basic research to application for surface two-dimensional metal-organic networks. Specifically, the metal single-crystal substrate with an HATP-Cu network can be used as a surface catalytic active layer to promote the adsorption, activation, or catalytic reaction of small molecules; it can be used to construct detection sensors for gas molecules, biomolecules, or chemical molecules; or it can be used as a two-dimensional conductive coordination material in the functional layer of electronic devices.

[0036] Example 1 S1. Obtain an Ag(111) single crystal substrate and pretreat the metal single crystal substrate. Specifically, the Ag(111) single crystal substrate is cleaned by argon ion beam sputtering to remove surface contaminants and adsorption layers. At the same time, thermal annealing is performed to obtain an atomically flat and clean Ag(111) surface, which is suitable for molecular deposition and subsequent interface reactions.

[0037] S2. Place the surface-cleaned Ag(111) single crystal substrate in a sealed chamber and run it under ultra-high vacuum conditions (vacuum degree better than 1e). -9 HATP molecules were deposited on the surface of an Ag(111) single crystal substrate. The deposition reaction was stopped when the HATP molecules were adsorbed on the surface of the Ag(111) single crystal substrate with a coverage of about 0.3 monolayers.

[0038] S3. Introduce oxygen into the chamber to maintain the oxygen concentration in the chamber at 5 × 10⁻⁶. -9 The Ag(111) single-crystal substrate with HATP molecules adsorbed on its surface was exposed to an oxygen atmosphere at a pressure of mbar. Under this atmosphere, the amino groups in the HATP molecules underwent dehydrogenation activation and further interfacial coordination reactions with the metal atoms on the Ag(111) surface, thereby inducing the formation of an ordered molecular-metal template structure. After 5 minutes of exposure, the Ag(111) single-crystal substrate was removed for characterization, and its STM scan results are as follows: Figure 1 As shown.

[0039] Depend on Figure 1It can be seen that an HATP-Ag template network structure was successfully formed on the surface of the Ag(111) single crystal substrate, and the formed HATP-Ag template network exhibits a periodic two-dimensional arrangement structure.

[0040] Comparative Example 1 S1. Obtain an Au(111) single crystal substrate and perform surface cleaning treatment on the Au(111) single crystal substrate by ion beam sputtering to obtain an atomically flat and clean Au(111) single crystal substrate surface, which is suitable for molecular deposition and subsequent interface reactions.

[0041] S2. Place the surface-cleaned Au(111) single crystal substrate in a sealed chamber and deposit HATP molecules on the surface of the Au(111) single crystal substrate under ultra-high vacuum conditions. Stop the deposition reaction when the HATP molecules are adsorbed on the surface of the Au(111) single crystal substrate with a coverage of about 0.3 monolayers.

[0042] S3. Introduce oxygen into the chamber to maintain the oxygen concentration at 1.33 × 10⁻⁶. -6 An oxygen atmosphere was applied to an Au(111) single crystal substrate with HATP molecules adsorbed on its surface. After 5 minutes of exposure, the Au(111) single crystal substrate was removed and characterized. The STM scan results are shown below. Figure 2 As shown.

[0043] Depend on Figure 2 It can be seen that no HATP-Au ordered template network structure was observed on the surface of the Au(111) single crystal substrate.

[0044] Comparing Example 1 and Comparative Example 1, it can be seen that under the same HATP molecule deposition conditions, the Ag(111) single crystal substrate can induce HATP molecules to undergo amino dehydrogenation activation with the participation of a small amount of oxygen, and further coordinate and assemble with Ag atoms on the surface, thereby forming an ordered two-dimensional HATP-Ag template network structure. However, on the Au(111) single crystal substrate surface, no corresponding ordered network structure was observed to form even under higher oxygen concentrations. Therefore, it can be seen that exposing the Au(111) single crystal substrate with HATP molecules adsorbed on the surface to an oxygen atmosphere is not an active process control step in the commonly used preparation route of this HATP-Au network. In addition, combined with the interfacial chemical reaction characteristics, it can be seen that the Ag(111) surface is more conducive to the formation of stable molecular-metal coordination structures under oxygen-assisted conditions, while the Au(111) surface is more inert and not conducive to amino activation and interfacial coordination reactions, thus preventing the spontaneous construction of the template structure. Compared to Au(111) single crystal substrates, Ag(111) single crystal substrates play a key role in oxygen-assisted interface self-assembly systems and are suitable substrates for the controllable fabrication of HATP-metal ordered template networks.

[0045] Example 2 S1. Obtain three sets of Ag(111) single crystal substrates with the same specifications. Perform surface cleaning treatment on the three sets of Ag(111) single crystal substrates using conventional single crystal surface cleaning methods to obtain clean Ag(111) single crystal substrates suitable for molecular deposition and subsequent reactions.

[0046] S2. Place the three groups of Ag(111) single crystal substrates in a sealed chamber and deposit HATP molecules under the same ultra-high vacuum conditions so that the HATP molecules are adsorbed on the surface of the Ag(111) single crystal substrates, and the HATP molecule coverage on the surface of the three groups of Ag(111) single crystal substrates is about 0.3 monolayers.

[0047] S3. Oxygen is introduced into the sealed chambers corresponding to the three groups of Ag(111) single crystal substrates, respectively, so that the oxygen partial pressure in the chamber is maintained at 1.0 × 10⁻⁶. -8 mbar, 2.8×10 -8 mbar and 5×10 -7 The three Ag(111) single crystal substrates with HATP molecules adsorbed on their surfaces were exposed to an oxygen atmosphere at a pressure of mbar, which induced an interfacial coordination reaction between the HATP molecules and the metal atoms on the Ag(111) single crystal substrate surface. After 5 minutes of exposure, the three Ag(111) single crystal substrates were removed and characterized. The STM scan results are shown below. Figure 3 As shown.

[0048] Depend on Figure 3 It can be seen that under different oxygen concentrations, all three groups of Ag(111) single crystal substrates formed periodically arranged two-dimensional HATP-metal template network structures on their surfaces, but their specific structural types differed significantly, corresponding to the formation of... Figure 3 The HATP-Ag-α template network shown in (a) and (d) is as follows: Figure 3 The HATP-Ag-β template network shown in (b) and (e) and as shown in the figure Figure 3 The HATP-Ag-γ template networks are shown in (c) and (f). This result demonstrates that by controlling the oxygen partial pressure, the activation level of the amino groups in the HATP molecule and the interfacial coordination assembly pathway can be adjusted, thereby inducing the formation of HATP-Ag template networks with different structural types. This further illustrates that oxygen not only participates in the interfacial reaction process as a reaction atmosphere but also plays a controllable role as a key process variable in the formation mode and final periodic arrangement of molecular-metal self-assembly structures.

[0049] Example 3 The HATP-Ag-α template network structure obtained in Example 2 was exposed to an oxygen atmosphere again for treatment, with the oxygen partial pressure maintained at 2.8 × 10⁻⁶. -8 An exposure of mbar for 5 minutes induced an interfacial coordination reaction between HATP molecules and metal atoms on the surface of the Ag(111) single-crystal substrate. After 5 minutes of exposure, the single-crystal substrate was removed and characterized. The STM scan results are shown below. Figure 4 As shown.

[0050] Depend on Figure 4 It was observed that the HATP-Ag-α template network structure transformed into the HATP-Ag-γ template network structure. This result indicates that by controlling oxygen treatment methods, such as adjusting oxygen partial pressure and stepwise oxygen introduction, it is possible to selectively obtain different types of HATP-Ag template networks and further achieve controllable transformation between different template network structures. This result also further confirms that oxygen not only participates in the interfacial coordination reaction process as a reaction atmosphere but also serves as a key process variable for regulating the degree of amino dehydrogenation activation of HATP molecules and the interfacial self-assembly pathway, thereby affecting the structural selectivity and dynamic evolution behavior of the template network.

[0051] Example 4 Subsequent experiments were conducted using the HATP-Ag-α template network, HATP-Ag-β template network, and HATP-Ag-γ template network obtained in Example 2, respectively, involving subsequent copper atom deposition and annealing. Specifically: S4. Copper atoms are formed by evaporating a copper metal evaporation source using a thermal evaporation process and deposited on the surfaces of the HATP-Ag-α template network, HATP-Ag-β template network, and HATP-Ag-γ template network. The deposition amount is controlled to form copper clusters with a diameter of 15 nm in the HATP-Ag-α template network, HATP-Ag-β template network, and HATP-Ag-γ template network.

[0052] S5. At 300℃, HATP-Ag-α, HATP-Ag-β, and HATP-Ag-γ template networks deposited with copper atoms were annealed to induce a substitution reaction between copper atoms and the Ag metal coordination nodes in the HATP-metal template network. After annealing for 15 min, the substrates were allowed to cool naturally, yielding three sets of metal single-crystal substrates with HATP-Cu networks on their surfaces. The STM scan results of these three sets of metal single-crystal substrates with HATP-Cu networks are shown below. Figure 5 As shown.

[0053] Depend on Figure 5It can be seen that after copper atom deposition and annealing, the three HATP-Ag-α template networks, HATP-Ag-β template networks, and HATP-Ag-γ template networks with different initial structures can all be transformed into a structurally consistent HATP-Cu two-dimensional metal-organic network. Among them, Figure 5 (b) shows the HATP-Cu two-dimensional metal-organic network formed by copper atom deposition and annealing of the HATP-Ag-α template network. Figure 5 (a) shows the HATP-Cu two-dimensional metal-organic network formed after copper atom deposition and annealing of the HATP-Ag-γ template network. This indicates that although the three initial template networks differ in structural arrangement and local coordination environment, they can all undergo Ag–Cu node substitution under copper atom participation and specific annealing conditions, thus forming a stable HATP-Cu network structure. This result suggests that the HATP-Ag template network can serve as a precursor template structure for copper substitution reactions, enabling the transformation of different initial template structures into a unified HATP-Cu target network. Among them, compared with the HATP-Ag-β and HATP-Ag-γ template networks, the HATP-Ag-α template network has a relatively low degree of amino activation, which may exhibit a certain degree of network expansion limitation during subsequent copper substitution, but it can still achieve complete transformation into the HATP-Cu structure.

[0054] Comparative Example 2 An Ag(111) single-crystal substrate was obtained and subjected to routine surface cleaning. Subsequently, HATP molecules and copper atoms were sequentially deposited on the Ag(111) surface. After deposition, the sample was annealed at 300℃ for 15 minutes. After annealing, it was allowed to cool naturally to room temperature before being removed and characterized. The STM scan results are shown below. Figure 6 As shown.

[0055] Depend on Figure 6 It can be seen that a partial HATP-Cu two-dimensional network structure can be formed on the surface of the Ag(111) single crystal substrate, but this network structure exhibits local discontinuities, limited lateral expansion, and obvious copper cluster residues and incompletely reacted HATP molecules. Compared with the HATP-Cu network obtained by guiding the copper substitution reaction with the HATP-Ag template network in Example 4, the HATP-Cu network obtained by the direct sequential deposition-annealing path in Comparative Example 2 is significantly deficient in terms of structural integrity, long-range order, and coverage continuity. This result indicates that in the absence of the HATP-Ag template network pre-assembled structure for guidance, the interfacial reaction process between copper atoms and HATP molecules is more prone to local disordered aggregation and incomplete coordination reactions, thus limiting the uniform construction and large-area continuous growth of the HATP-Cu two-dimensional network.

[0056] The thermal stability of the HATP-Cu network on the surface of the metal single-crystal substrate obtained in Example 4 was tested. Specifically, the metal single-crystal substrate with the HATP-Cu network was heat-treated at 350°C and 400°C for a certain period of time, then removed and its surface structure was characterized using a scanning tunneling microscope (STM). The results are as follows. Figure 7 As shown.

[0057] Depend on Figure 7 As shown in (a), after heat treatment at 350℃ for 10 min, the HATP-Cu network still maintains a good periodic arrangement and continuous two-dimensional topology, indicating that the HATP-Cu network has good structural stability under heat treatment at 350℃. Figure 7 As shown in (b), when the heat treatment temperature rises to 400℃, the HATP-Cu network begins to exhibit significant structural reconstruction, and the degree of periodic order decreases. These results indicate that the HATP-Cu two-dimensional network constructed in this application can still maintain a good two-dimensional ordered structure after heat treatment at 350℃, demonstrating high thermal stability.

[0058] Without pre-constructing an HATP-Ag template network, directly depositing HATP molecules and copper atoms on the surface of an Ag(111) single-crystal substrate followed by annealing only results in a locally limited HATP-Cu network structure, accompanied by significant copper cluster residues and unreacted HATP molecules. In contrast, the HATP-Cu network obtained using the "oxygen-induced preparation of HATP-Ag template network construction - copper atom replacement" technique provided in this application can extend its lateral size to hundreds of nanometers and maintain good structural integrity and periodic ordered arrangement characteristics after heat treatment at 350℃. Compared to the traditional direct deposition-annealing method, the preparation method provided in this application shows significant improvements in the lateral expansion capability, structural integrity, assembly order, and thermal stability of the two-dimensional network.

[0059] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0060] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A single-crystal metal substrate with an HATP-Cu network on its surface, characterized in that, include: Metal single crystal substrate; An HATP-Cu network is constructed on the surface of the metal single crystal substrate. The HATP-Cu network includes HATP ligands and copper metal coordination nodes. Adjacent HATP ligands are coordinated and connected through the copper metal coordination nodes. The copper metal coordination nodes are arranged in a preset periodic pattern at the connection positions between adjacent HATP ligands, so that the HATP ligands and the copper metal coordination nodes form a continuous HATP-Cu network on the surface of the metal single crystal substrate.

2. The metal single-crystal substrate as described in claim 1, characterized in that, The HATP-Cu network exhibits a two-dimensional periodic coordination structure, and the HATP-Cu network retains its two-dimensional periodic coordination structure even under heat treatment conditions of 320℃-370℃. The lateral dimension of the HATP-Cu network is not less than 50 nm.

3. The metal single-crystal substrate as described in claim 1 or 2, characterized in that, The metal single crystal substrate is an Ag(111) single crystal substrate.

4. A method for preparing a single-crystal metal substrate with an HATP-Cu network on its surface as described in any one of claims 1-3, characterized in that, Includes the following steps: S1. Obtain a metal single crystal substrate and pre-treat the metal single crystal substrate. The pre-treatment includes surface cleaning of the metal single crystal substrate to remove contaminants on the surface of the metal single crystal substrate and obtain an atomically flat metal single crystal surface. S2. Under ultra-high vacuum conditions, HATP ligand molecules are deposited on the surface of the pretreated metal single crystal substrate, so that the HATP ligand molecules are adsorbed on the surface of the metal single crystal substrate according to a preset coverage. S3. Expose the metal single crystal substrate with HATP ligand molecules adsorbed on its surface to an oxygen atmosphere, so that the HATP ligand molecules and the metal single crystal substrate undergo an interfacial coordination reaction, promoting the formation of metal coordination nodes between adjacent HATP ligand molecules, and forming a continuous HATP-metal template network with a periodic network structure. S4. Deposit copper atoms on the surface of the HATP-metal template network, so that the copper atoms are distributed near the metal coordination nodes of the HATP-metal template network; S5. Anneal the HATP-metal template network on which the copper atoms are deposited, so that the copper atoms migrate to the surface during the annealing process and replace the original metal coordination nodes in the HATP-metal template network, and re-coordinate with the HATP ligand molecules to form copper metal coordination nodes, thereby causing the coordination nodes of the HATP-metal template network to be reconstructed, and a metal single crystal substrate with an HATP-Cu network on the surface is obtained.

5. The preparation method according to claim 4, characterized in that, In step S5, the copper metal coordination node is formed by the copper atom coordinating with the nitrogen atom in the adjacent HATP ligand molecule to connect the adjacent HATP ligand molecule and replacing the original metal coordination node in the HATP-metal template network.

6. The preparation method according to claim 4, characterized in that, In step S2, the preset coverage is a sub-monolayer. In step S3, the oxygen is introduced into the oxygen atmosphere either continuously or in stages.

7. The preparation method according to claim 4, characterized in that, In step S3, the structure of the HATP-metal template network is adjusted by regulating the oxygen concentration or the exposure time and number of times the metal single crystal substrate is exposed to an oxygen atmosphere. The oxygen concentration is 1×10⁻⁶ -9 mbar~1×10 -5 Any value in mbar; The exposure duration is any value between 3 min and 15 min; The number of exposures is 1 to 3 times.

8. The preparation method according to claim 4, characterized in that, The HATP-metal template network is an HATP-Ag template network formed on the surface of an Ag(111) single crystal substrate; the HATP-Ag template network has a two-dimensional periodic network structure; The HATP-Ag template network is any one or more of the HATP-Ag-α template network, HATP-Ag-β template network, and HATP-Ag-γ template network.

9. The preparation method according to claim 4, characterized in that, In step S4, the copper atoms are deposited on the surface of the HATP-metal template network by thermal evaporation, electron beam evaporation or molecular beam epitaxy. In step S5, the annealing temperature is 200℃~400℃.

10. The application of the metal single crystal substrate with HATP-Cu network on the surface as described in any one of claims 1-3 or the metal single crystal substrate with HATP-Cu network on the surface prepared by the preparation method as described in any one of claims 4-9 in the preparation of two-dimensional electronic devices, molecular sensors, catalytic materials, and surface reaction template materials.

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