A single-layer Cu 2 / 3 Na 1 / 3 Se materials and their preparation methods

Abstract

This invention relates to a single-layer Cu 2 / 3 Na 1 / 3 This paper describes a method for preparing copper (Se) materials, belonging to the field of nanomaterials technology. The method involves preparing a copper single-crystal substrate; evaporating and depositing selenium powder onto the copper single-crystal substrate to obtain the substrate and a copper-selenium compound deposited on it, controlling the temperature of the copper-selenium compound and the copper single-crystal substrate at 25–30°C during the deposition process; heating the substrate and the deposited copper-selenium compound to the growth temperature and holding them thereafter; then evaporating and depositing elemental sodium onto the substrate and the copper-selenium deposit to obtain a sodium-doped copper selenide deposit and the substrate, controlling the temperature of the substrate and the deposit at 25–30°C during the deposition process; and finally, holding the obtained sodium-doped copper selenide deposit and the substrate at room temperature to obtain a large-area monolayer of Cu. 2 / 3 Na 1 / 3Se material. The large-area monolayer Cu prepared by this invention... 2 / 3Na 1 / 3 Se materials have a two-dimensional network structure with an area greater than 250 square nanometers and uniformly oriented atoms.

Description

Technical Field

[0001] This invention relates to the field of nanomaterials technology, specifically to a method for forming a single-layer Cu substrate by pre-depositing selenium powder to form a copper-selenium compound, followed by the addition of a small amount of elemental sodium to create a specific elemental ratio. 2 / 3 Na 1 / 3 Preparation method of Se materials. Background Technology

[0002] In recent decades, the rapid depletion of fossil fuels and the increasingly severe energy crisis have led to a growing demand for high-energy / power-density and low-cost rechargeable batteries. Consequently, the development of alternatives to traditional electrochemical energy storage systems has attracted increasing attention. In recent years, alkali metal chalcogenides have been extensively studied in the energy field as electrodes and electrolytes, especially with the participation of sodium ions, exhibiting high energy density and low cost, making them an attractive candidate material for next-generation energy storage systems. However, the large volumetric properties of most polyselenides result in unsatisfactory cycle performance. Therefore, finding an unconventional, stoichiometric sodium-doped copper selenide might offer a new option.

[0003] Two-dimensional materials have become a hot topic in the scientific community recently due to their rich physicochemical properties and potential for enormous applications, which also provides new opportunities for the development of novel electronic devices. Among all two-dimensional transition metal monochalcogenide materials with graphene-like structures, monolayer copper selenide materials have attracted widespread attention.

[0004] Naturally patterned monolayer copper selenide materials can serve as templates for the adsorption and doping of specific atoms and molecules at specific sites. If surface physicochemical methods are used, with monolayer copper selenide as a template, materials with specific elemental ratios can be prepared. This allows for the understanding and design of subsequent experimental methods based on the morphology, thus providing a meaningful strategy for its practical applications. Summary of the Invention

[0005] To address the problems and shortcomings of the existing technology, this invention provides a single-layer Cu with a specific elemental ratio. 2 / 3Na 1 / 3 Se materials and their preparation methods. Specifically, this invention utilizes the strategy that selenium powder reacts chemically with a copper substrate to form a compound. Selenium powder is deposited onto the surface of a copper substrate to obtain a sample with copper-selenium compounds and selenium atoms on the substrate. The sample is then heated to a growth temperature and annealed. Sodium is then deposited onto the sample surface, and the sample is heated to room temperature and annealed again, ultimately yielding a monolayer Cu with a specific elemental ratio. 2 / 3 Na1 / 3 Samples with a network structure composed of Se.

[0006] A single-layer Cu 2 / 3 Na 1 / 3 Se materials and their preparation methods, characterized by specifically including:

[0007] Step 1: Prepare a copper single-crystal substrate;

[0008] Step 2: Selenium powder is evaporated and deposited onto the copper single crystal substrate of Step 1 to obtain the substrate and the copper selenium compound deposited on the substrate. The temperature of the copper selenium compound on the substrate and the copper single crystal substrate is controlled at 25-30℃ during the deposition process.

[0009] Step 3: The substrate from Step 2 and the copper selenium compound deposited on the substrate are subjected to a first heating and holding treatment to the growth temperature.

[0010] Step 4: Then, elemental sodium is evaporated and deposited onto the substrate and copper-selenium deposit treated in Step 3 to obtain sodium-doped copper selenide deposit and substrate. The temperature of the substrate and deposit is controlled at 25-30℃ during the deposition process.

[0011] Step 5: The sodium-doped copper selenide deposit obtained in Step 4 and the substrate are subjected to a room temperature incubation treatment to obtain a large-area monolayer Cu. 2 / 3 Na 1 / 3 Se materials.

[0012] The preparation process of the copper single crystal substrate is as follows:

[0013] Step 1.1: In an ultra-high vacuum chamber, an argon ion sputtering process is performed on a copper substrate to obtain a copper substrate;

[0014] Step 1.2: Heat the copper substrate obtained in Step 1.1 to 450℃ and hold for 10-30 minutes to obtain a copper single crystal substrate.

[0015] In step 2, the deposition temperature of the selenium powder is 120℃~125℃; the deposition time of the selenium powder is 15min~20min.

[0016] In step 3, the growth temperature is 100–400℃, and the temperature is maintained for 30 minutes.

[0017] In step 4, the deposition temperature of elemental sodium is 700℃~710℃, and the deposition time of elemental sodium is 5min~10min.

[0018] The stoichiometric ratio of the above-mentioned selenium powder to copper substrate to form copper selenium compound is including but not limited to 1:1, and the stoichiometric ratio of sodium element to substrate and copper selenium deposit is including but not limited to 1:5.

[0019] The beneficial effects of this invention are:

[0020] (1) This invention can prepare large-area monolayer Cu 2 / 3 Na 1 / 3 SE network products, this Cu 2 / 3 Na 1 / 3 The internal structure of SE network products is two-dimensional, regular, and orderly, and has a large area.

[0021] (2) The large-area monolayer Cu prepared by this invention 2 / 3 Na 1 / 3 Se network products are composed of a planar hexagonal honeycomb structure made of copper atoms, selenium atoms, and sodium atoms;

[0022] (3) The large-area two-dimensional monolayer Cu prepared by this invention 2 / 3 Na 1 / 3 The Se network area is greater than 250 square nanometers, and the ratio of sodium atoms, copper atoms and selenium atoms is 1:2:3. Attached Figure Description

[0023] Figure 1 A monolayer Cu with a specific elemental ratio is shown according to an embodiment of the present invention. 2 / 3 Na 1 / 3 Scanning tunneling microscope images of Se material;

[0024] Figure 2 A monolayer Cu with a specific elemental ratio is shown according to an embodiment of the present invention. 2 / 3 Na 1 / 3 Scanning tunneling microscopy atomic resolution images of Se materials, cell structure and periodicity;

[0025] Figure 3 A monolayer Cu with a specific elemental ratio is shown according to an embodiment of the present invention. 2 / 3 Na 1 / 3 Scanning tunneling microscope images of Se material and a computationally simulated monolayer Cu with specific elemental ratios. 2 / 3 Na 1 / 3 Scanning tunneling microscope image of Se material and corresponding monolayer Cu 2 / 3 Na 1 / 3 Optimized atomic configuration of Se materials. Detailed Implementation

[0026] The present invention will be further described in detail below with reference to specific embodiments. The embodiments given are only for illustrating the present invention and are not intended to limit the scope of the present invention.

[0027] Test instruments and equipment:

[0028] Cryogenic scanning tunneling microscope: purchased from Omicron GmbH, Germany.

[0029] K-cell molecular evaporation source: purchased from Omicron, Germany.

[0030] Argon ion gun: purchased from Omicron, Germany.

[0031] Alkali metal evaporation source: designed and assembled in-house.

[0032] raw material:

[0033] Selenium powder: purchased from Sigma-Aldrich, purity 99.99%.

[0034] Copper single crystal: purchased from MaTecK, purity 99.999%.

[0035] Sodium: purchased from SAES, purity 99.99%.

[0036] Copper single crystal: purchased from MaTecK, purity 99.999%.

[0037] Example 1

[0038] This large-area two-dimensional monolayer Cu 2 / 3 Na 1 / 3 The preparation method of Se network includes the following specific steps:

[0039] Step 1: Preparation of copper single crystal substrate; The preparation process of copper single crystal substrate is as follows:

[0040] Step 1.1: In an ultra-high vacuum chamber, an argon ion sputtering process is performed on a copper substrate to obtain a copper substrate;

[0041] Step 1.2: Heat the copper substrate obtained in Step 1.1 to 450℃ and hold for 10-30 minutes to obtain a copper single crystal substrate.

[0042] Step 2: 500mg selenium powder is evaporated and deposited on the 50g copper single crystal substrate from Step 1 using a thermally resistive K-cell molecular evaporation source at an evaporation temperature of 120℃ to obtain the substrate and the copper selenium compound deposited on the substrate. The temperature of the copper selenium compound on the substrate and the copper single crystal substrate is controlled at 30℃ during the deposition process, and the deposition time is 30min.

[0043] Step 3: The substrate from Step 2 and the copper selenium compound deposited on the substrate are subjected to a first heating and holding treatment at the growth temperature of 200℃ for 30 minutes.

[0044] Step 4: Then, 1 mg of sodium elemental was evaporated and deposited on 50 g of substrate and copper selenide deposit treated in step 3 at a DC evaporation source at an evaporation temperature of 700 °C to obtain sodium-doped copper selenide deposit and substrate. The temperature of the substrate and deposit was controlled at 30 °C during the deposition process and the deposition time was 10 min.

[0045] Step 5: The sodium-doped copper selenide deposit obtained in Step 4 and the substrate are subjected to a room temperature incubation treatment to obtain a large-area monolayer Cu. 2 / 3 Na 1 / 3 Se materials.

[0046] The large-area two-dimensional monolayer Cu prepared in this embodiment 2 / 3 Na 1 / 3 The image is a network scanning tunneling microscope image. Figure 1 As shown, from Figure 1 It can be seen that the product of this invention is a large-area two-dimensional monolayer Cu. 2 / 3 Na 1 / 3 Se network.

[0047] The large-area two-dimensional monolayer Cu prepared in this embodiment 2 / 3 Na 1 / 3 Se network scanning tunneling microscope atomic resolution image and unit cell structure diagram ( Figure 2 It can be seen that a large-area two-dimensional monolayer Cu 2 / 3 Na 1 / 3 The unit cell length of the Se network is 0.76 nm.

[0048] The large-area two-dimensional monolayer Cu prepared in Example 1 2 / 3 Na 1 / 3 Scanning tunneling microscope images, computational simulation diagrams, and atomic model diagrams of Se networks are shown below. Figure 3 As shown, from Figure 3 This directly and effectively demonstrates that the large-area two-dimensional regular ordered monolayer Cu prepared by the preparation method according to the embodiments of the present invention can be used to prepare the product. 2 / 3 Na 1 / 3 Se network is a hexagonal honeycomb lattice structure composed of copper atoms, selenium atoms, and sodium atoms, with the ratio of sodium atoms, copper atoms, and selenium atoms being 1:2:3.

[0049] Example 2

[0050] This large-area two-dimensional monolayer Cu 2 / 3 Na 1 / 3 The preparation method of Se network includes the following specific steps:

[0051] Step 1: Preparation of copper single crystal substrate; The preparation process of copper single crystal substrate is as follows:

[0052] Step 1.1: In an ultra-high vacuum chamber, an argon ion sputtering process is performed on a copper substrate to obtain a copper substrate;

[0053] Step 1.2: Heat the copper substrate obtained in Step 1.1 to 450℃ and hold for 10-30 minutes to obtain a copper single crystal substrate.

[0054] Step 2: 500mg selenium powder was evaporated and deposited on the 50g copper single crystal substrate from Step 1 using a thermally resistive K-cell molecular evaporation source at an evaporation temperature of 125℃ to obtain the substrate and the copper selenium compound deposited on the substrate. During the deposition process, the temperature of the copper selenium compound on the substrate and the copper single crystal substrate was controlled at 30℃, and the deposition time was 25min.

[0055] Step 3: The substrate from Step 2 and the copper selenium compound deposited on the substrate are subjected to a first heating and holding treatment at the growth temperature of 300℃ for 30 minutes.

[0056] Step 4: Then, 1 mg of sodium elemental was evaporated and deposited on 50 g of substrate and copper selenide deposit treated in step 3 using a DC evaporation source at an evaporation temperature of 710 °C to obtain sodium-doped copper selenide deposit and substrate. The temperature of the substrate and deposit was controlled at 30 °C during the deposition process, and the deposition time was 5 min.

[0057] Step 5: The sodium-doped copper selenide deposit obtained in Step 4 and the substrate are subjected to a room temperature incubation treatment to obtain a large-area monolayer Cu. 2 / 3 Na 1 / 3 Se materials.

[0058] Example 3

[0059] The specific steps of preparing this large-area two-dimensional sodium-doped copper selenide network include:

[0060] Step 1: Preparation of copper single crystal substrate; The preparation process of copper single crystal substrate is as follows:

[0061] Step 1.1: In an ultra-high vacuum chamber, an argon ion sputtering process is performed on a copper substrate to obtain a copper substrate;

[0062] Step 1.2: Heat the copper substrate obtained in Step 1.1 to 450℃ and hold for 10-30 minutes to obtain a copper single crystal substrate.

[0063] Step 2: 500mg selenium powder was evaporated and deposited on the 50g copper single crystal substrate from Step 1 using a thermally resistive K-cell molecular evaporation source at an evaporation temperature of 125℃ to obtain the substrate and the copper selenium compound deposited on the substrate. During the deposition process, the temperature of the copper selenium compound on the substrate and the copper single crystal substrate was controlled at 30℃, and the deposition time was 25min.

[0064] Step 3: The substrate from Step 2 and the copper selenium compound deposited on the substrate are subjected to a first heating and holding treatment at the growth temperature of 400℃ for 30 minutes.

[0065] Step 4: Then, 1 mg of sodium elemental was evaporated and deposited on 50 g of substrate and copper selenide deposit treated in step 3 at an evaporation temperature of 705 °C using a DC evaporation source to obtain sodium-doped copper selenide deposit and substrate. The temperature of the substrate and deposit was controlled at 30 °C during the deposition process, and the deposition time was 7 min.

[0066] Step 5: The sodium-doped copper selenide deposit obtained in Step 4 and the substrate are subjected to a room temperature incubation treatment to obtain a large-area monolayer Cu. 2 / 3 Na 1 / 3 Se materials.

[0067] The specific embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A single-layer Cu 2 / 3 Na 1 / 3 Se material, characterized in that: The single-layer Cu 2 / 3 Na 1 / 3 Se material, whose structural area is greater than 250 square nanometers, and all sodium-doped copper selenide compounds form a network structure in a hexagonal honeycomb shape, with the ratio of sodium, copper and selenium elements being 1:2:3; The single-layer Cu 2 / 3 Na 1 / 3 Methods for preparing Se materials include: Step 1: Prepare a copper single-crystal substrate; Step 2: Selenium powder is evaporated and deposited onto the copper single crystal substrate of Step 1 to obtain the substrate and the copper selenium compound deposited on the substrate. The temperature of the copper selenium compound on the substrate and the copper single crystal substrate is controlled at 25-30℃ during the deposition process. Step 3: The substrate from Step 2 and the copper selenium compound deposited on the substrate are subjected to a first heating and holding treatment to the growth temperature. Step 4: Then, elemental sodium is evaporated and deposited onto the substrate and copper-selenium deposit treated in Step 3 to obtain sodium-doped copper selenide deposit and substrate. The temperature of the substrate and deposit is controlled at 25-30℃ during the deposition process. Step 5: The sodium-doped copper selenide deposit obtained in Step 4 and the substrate are subjected to a room temperature incubation treatment to obtain a large-area monolayer Cu. 2 / 3 Na 1 / 3 SE materials; The deposition time of the selenium powder is 15 to 20 minutes, and the deposition time of the sodium element is 5 to 10 minutes.

2. The single-layer Cu according to claim 1 2 / 3 Na 1 / 3 Se material, characterized in that: The preparation process of the copper single crystal substrate is as follows: Step 1.1: In an ultra-high vacuum chamber, an argon ion sputtering process is performed on a copper substrate to obtain a copper substrate; Step 1.2: Heat the copper substrate obtained in Step 1.1 to 450℃ and hold for 10-30 minutes to obtain a copper single crystal substrate.

3. The single-layer Cu according to claim 1 2 / 3 Na 1 / 3 Se material, characterized in that: The deposition temperature of the selenium powder is 120℃~125℃, and the deposition temperature of elemental sodium is 700℃~710℃.

4. The single-layer Cu according to claim 1 2 / 3 Na 1 / 3 Se material, characterized in that: The growth temperature is 100–400℃, and the temperature is maintained for 30 minutes.

Images