A high-entropy sulfide, its preparation method and application

Abstract

This invention provides a high-entropy sulfide, its preparation method, and its applications, relating to the field of high-entropy materials technology. The invention uses a mixture of molybdenum trioxide, tantalum pentoxide, vanadium dioxide, tungsten trioxide, and titanium dioxide as the metal source and sulfur powder as the sulfur source. By preheating the second and third temperature zones to 850-950℃ and 1050-1100℃ respectively, and then placing the metal source and reaction substrate in the second and third temperature zones respectively, rapid heating of the metal source and reaction substrate can be achieved. After the reaction, the reaction product is rapidly cooled with liquid nitrogen, which can prevent elemental segregation in the prepared high-entropy sulfide. Furthermore, the two-dimensional high-entropy sulfide provided by this invention exhibits excellent photoelectric response performance and has broad application prospects in the field of optoelectronic technology.

Description

Technical Field

[0001] This invention relates to the field of high-entropy materials technology, and more specifically, to a high-entropy sulfide, its preparation method, and its application. Background Technology

[0002] The controllable preparation of large-area, high-quality two-dimensional crystal materials is a crucial foundation for their application in optoelectronics, flexible devices, and other fields. Among them, two-dimensional high-entropy sulfide materials, as an emerging nanomaterial system, combine the advantages of two-dimensional nanomaterials and high-entropy alloys, possessing unique metallic compositions and tunable band structures, exhibiting excellent performance in optoelectronic detection. Currently, high-entropy sulfides can generally be prepared by high-temperature solid-state methods and solvothermal methods. However, due to the presence of multiple elements in high-entropy sulfides, each with different physical properties, elemental segregation is prone to occur during nucleation and growth. Summary of the Invention

[0003] The problem solved by this invention is that high-entropy sulfides prepared by existing methods are prone to elemental segregation.

[0004] To address the above problems, this invention provides a method for preparing high-entropy sulfides, based on a high-temperature tube furnace having a first temperature zone, a second temperature zone, and a third temperature zone, comprising:

[0005] Step S1: Introduce carrier gas into the high-temperature tubular furnace, place sulfur powder in the first temperature zone, and raise the temperature of the first temperature zone, the second temperature zone, and the third temperature zone to the first temperature, the second temperature, and the third temperature, respectively.

[0006] Step S2: Place the metal source and the reaction substrate in the second temperature zone and the third temperature zone respectively, maintain for a preset time, and cool the obtained reaction product in liquid nitrogen to obtain a high-entropy sulfide.

[0007] The metal source is composed of a mixture of molybdenum trioxide, tantalum pentoxide, vanadium dioxide, tungsten trioxide, and titanium dioxide; the first temperature zone, the second temperature zone, and the third temperature zone are arranged sequentially along the flow direction of the carrier gas, the first temperature is 300-350℃, the second temperature is 850-950℃, and the third temperature is 1050-1100℃.

[0008] Optionally, in the metal source, the mass ratio of molybdenum trioxide, tantalum pentoxide, vanadium dioxide, tungsten trioxide and titanium dioxide is (4-6):(0.9-1.1):(0.9-1.1):(4-6):1.

[0009] Optionally, the mass ratio of the sulfur powder to the metal source is (4-6):1.

[0010] Optionally, in step S2, the preset time is 15-30 minutes.

[0011] Optionally, in step S1, the carrier gas is nitrogen.

[0012] Optionally, the flow rate of the carrier gas is 35-55 sccm.

[0013] Optionally, in step S2, the material of the reaction substrate includes one of sapphire, silicon, and aluminum nitride.

[0014] Optionally, the reaction substrate is made of sapphire.

[0015] The present invention also provides a high-entropy sulfide, which is prepared by the high-entropy sulfide preparation method described above.

[0016] The present invention also provides an application of the high-entropy sulfide described above in the field of optoelectronic technology.

[0017] Compared with existing technologies, this invention uses a mixture of molybdenum trioxide, tantalum pentoxide, vanadium dioxide, tungsten trioxide, and titanium dioxide as the metal source and sulfur powder as the sulfur source. By preheating the second and third temperature zones to 850-950℃ and 1050-1100℃ respectively, and then placing the metal source and reaction substrate in the second and third temperature zones respectively, rapid heating of the metal source and reaction substrate can be achieved. After the reaction, the reaction product is rapidly cooled with liquid nitrogen, which can prevent elemental segregation in the obtained high-entropy sulfide. In addition, the two-dimensional high-entropy sulfide provided by this invention has excellent photoelectric response performance and has broad application prospects in the field of optoelectronic technology. Attached Figure Description

[0018] Figure 1 This is a schematic flowchart of the method for preparing high-entropy sulfides in an embodiment of the present invention;

[0019] Figure 2 XRD images of the high-entropy sulfides prepared in Comparative Example 1;

[0020] Figure 3 An optical microscope image of the high-entropy sulfide prepared in Example 1;

[0021] Figure 4 The images show the scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) analysis of the high-entropy sulfide prepared in Example 1.

[0022] Figure 5 The Raman spectrum of the high-entropy sulfide prepared in Example 1;

[0023] Figure 6 This is a comparison chart of the output characteristics of the field-effect transistor in the application example under conditions of no light and laser irradiation with a wavelength of 405nm. Detailed Implementation

[0024] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Although some embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the accompanying drawings and embodiments of the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0025] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit this application.

[0026] The term "comprising" and its variations as used herein are open-ended, meaning "including but not limited to"; the term "based on" means "at least partially based on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments"; and the term "optionally" means "optional embodiments". Definitions of other terms will be given in the description below. It should be noted that the concepts of "first," "second," etc., mentioned in this invention are used to distinguish different objects, not to describe a specific order or hierarchy. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0027] like Figure 1 As shown, an embodiment of the present invention provides a method for preparing high-entropy sulfides, based on a high-temperature tube furnace having a first temperature zone, a second temperature zone, and a third temperature zone, comprising:

[0028] Step S1: Introduce carrier gas into the high-temperature tubular furnace, place sulfur powder in the first temperature zone, and raise the temperature of the first temperature zone, the second temperature zone, and the third temperature zone to the first temperature, the second temperature, and the third temperature, respectively.

[0029] Step S2: Place the metal source and the reaction substrate in the second temperature zone and the third temperature zone respectively, maintain for a preset time, and cool the obtained reaction product in liquid nitrogen to obtain a high-entropy sulfide.

[0030] The metal source is composed of a mixture of molybdenum trioxide, tantalum pentoxide, vanadium dioxide, tungsten trioxide, and titanium dioxide; the first temperature zone, the second temperature zone, and the third temperature zone are arranged sequentially along the flow direction of the carrier gas, the first temperature is 300-350℃, the second temperature is 850-950℃, and the third temperature is 1050-1100℃.

[0031] It should be noted that, in this invention, raising the first temperature zone, the second temperature zone, and the third temperature zone to the first temperature, the second temperature, and the third temperature respectively should be understood as: raising the first temperature zone to the first temperature, raising the second temperature zone to the second temperature, and raising the third temperature zone to the third temperature. Similarly, placing the metal source and the reaction substrate in the second temperature zone and the third temperature zone respectively should be understood as: placing the metal source in the second temperature zone and the reaction substrate in the third temperature zone.

[0032] High-entropy sulfides are generally prepared by high-temperature solid-state methods and solvothermal methods. Currently, there are no reports on the preparation of high-entropy sulfides by CVD. Moreover, in existing CVD preparation methods, the reactants are generally placed in a tube furnace, and then the reactants are heated from room temperature to a specified temperature to react. After the reaction, the reaction product is air-cooled or cooled to room temperature with the furnace.

[0033] This invention improves upon existing CVD methods by using a mixture of molybdenum trioxide, tantalum pentoxide, vanadium dioxide, tungsten trioxide, and titanium dioxide as the metal source and sulfur powder as the sulfur source. By preheating the second and third temperature zones to 850-950°C and 1050-1100°C, respectively, and then placing the metal source and reaction substrate in the second and third temperature zones, rapid heating of the metal source and reaction substrate can be achieved. After the reaction, the reaction products are rapidly cooled with liquid nitrogen, which can prevent elemental segregation of the obtained high-entropy sulfides.

[0034] In some embodiments of the present invention, the mass ratio of the molybdenum trioxide, the tantalum pentoxide, the vanadium dioxide, the tungsten trioxide and the titanium dioxide in the metal source is (4-6):(0.9-1.1):(0.9-1.1):(4-6):1.

[0035] In some embodiments of the present invention, the mass ratio of the sulfur powder to the metal source is (4-6):1.

[0036] In some embodiments of the present invention, the preset time in step S2 is 15-30 minutes.

[0037] In some embodiments of the present invention, in step S1, the carrier gas is nitrogen, and the flow rate of the carrier gas is 35-55 sccm.

[0038] In some embodiments of the present invention, in step S2, the reaction substrate is made of one of sapphire, silicon, and aluminum nitride. Preferably, the reaction substrate is made of sapphire.

[0039] This invention also provides a high-entropy sulfide, which is prepared using the high-entropy sulfide preparation method described above.

[0040] The present invention also provides an application of the high-entropy sulfide described above in the field of optoelectronic technology.

[0041] The present invention will be further described below with reference to specific embodiments.

[0042] Example 1: This example is implemented using a high-temperature tube furnace with a first temperature zone, a second temperature zone, and a third temperature zone. The first temperature zone, the second temperature zone, and the third temperature zone of the high-temperature tube furnace are arranged sequentially along the flow direction of the carrier gas.

[0043] A1. Introduce carrier gas into a high-temperature tubular furnace, place 5g of sulfur powder in the first temperature zone, raise the temperature of the first zone to 325℃, raise the temperature of the second zone to 900℃, and raise the temperature of the third zone to 1075℃; the carrier gas is nitrogen, and its flow rate is 45 sccm.

[0044] A2. Place 1g of metal source in the second temperature zone, place the reaction substrate in the third temperature zone, maintain for 20min, and cool the reaction product obtained on the reaction substrate in liquid nitrogen to obtain a high-entropy sulfide; wherein, the metal source is a mixture of molybdenum trioxide powder, tantalum pentoxide powder, vanadium dioxide powder, tungsten trioxide powder and titanium dioxide powder in a mass ratio of 5:1:1:5:1; the reaction substrate is a sapphire substrate.

[0045] Example 2: This example is implemented using a high-temperature tube furnace with a first temperature zone, a second temperature zone, and a third temperature zone. The first temperature zone, the second temperature zone, and the third temperature zone of the high-temperature tube furnace are arranged sequentially along the flow direction of the carrier gas.

[0046] A1. Introduce carrier gas into a high-temperature tubular furnace, place 5g of sulfur powder in the first temperature zone, raise the temperature of the first temperature zone to 300℃, raise the temperature of the second temperature zone to 850℃, and raise the temperature of the third temperature zone to 1050℃; the carrier gas is nitrogen, and its flow rate is 35sccm.

[0047] A2. Place 1g of metal source in the second temperature zone, place the reaction substrate in the third temperature zone, maintain for 20min, and cool the reaction product obtained on the reaction substrate in liquid nitrogen to obtain a high-entropy sulfide; wherein, the metal source is a mixture of molybdenum trioxide powder, tantalum pentoxide powder, vanadium dioxide powder, tungsten trioxide powder and titanium dioxide powder in a mass ratio of 4:1:1:4:1; the reaction substrate is a sapphire substrate.

[0048] Example 3: This example is implemented using a high-temperature tube furnace with a first temperature zone, a second temperature zone, and a third temperature zone. The first temperature zone, the second temperature zone, and the third temperature zone of the high-temperature tube furnace are arranged sequentially along the flow direction of the carrier gas.

[0049] A1. Introduce carrier gas into a high-temperature tubular furnace, place 5g of sulfur powder in the first temperature zone, raise the temperature of the first temperature zone to 350℃, raise the temperature of the second temperature zone to 950℃, and raise the temperature of the third temperature zone to 1100℃; the carrier gas is nitrogen, and its flow rate is 55sccm.

[0050] A2. Place 1g of metal source in the second temperature zone, place the reaction substrate in the third temperature zone, maintain for 20min, and cool the reaction product obtained on the reaction substrate in liquid nitrogen to obtain a high-entropy sulfide; wherein, the metal source is a mixture of molybdenum trioxide powder, tantalum pentoxide powder, vanadium dioxide powder, tungsten trioxide powder and titanium dioxide powder in a mass ratio of 6:1:1:6:1; the reaction substrate is a sapphire substrate.

[0051] Comparative Example 1: Synthesis of High-Entropy Sulfides via High-Temperature Solid-State Method

[0052] Mix and grind 3g of molybdenum powder, 6g of tantalum powder, 2g of vanadium powder, 6g of tungsten powder, 2g of titanium powder and 1g of sulfur powder evenly, and press the powder into tablets using a ring-shaped mold to obtain powder tablets.

[0053] The powder tablets were placed in a quartz tube and a vacuum was drawn. When the air pressure inside the quartz tube was 1.0 × 10⁻⁶, the pressure was increased to 1.0 × 10⁻⁶. -3 At Pa, the quartz tube was encapsulated using a flame torch. The encapsulated quartz tube was placed in a muffle furnace and heated to 1000℃ at a heating rate of 1℃ / min. After holding at this temperature for 100h, it was cooled with the furnace to obtain MoWTiTaVS2 high-entropy sulfide.

[0054] Application examples

[0055] The high-entropy sulfide obtained in Example 1 was used as a conductive channel to fabricate a field-effect transistor.

[0056] Experimental Example

[0057] The high-entropy sulfide obtained in Comparative Example 1 was characterized by XRD, and the results are shown in the figure. Figure 2 ,from Figure 2 It can be seen that the high-entropy sulfide prepared in Comparative Example 1 contains V5S8 phase (PDF#04-008-3925) precipitated in the 2H phase (PDF#04-002-9908) of MoS2, indicating that elemental segregation exists in the high-entropy sulfide prepared in Comparative Example 1.

[0058] The high-entropy sulfide prepared in Example 1 was characterized by optical microscopy, and the results are shown in the figure. Figure 3 ,from Figure 3As can be seen, the high-entropy sulfide prepared in Example 1 has a plate-like structure and belongs to two-dimensional high-entropy sulfides. Raman spectroscopy analysis of the high-entropy sulfide prepared in Example 1 is shown in the results. Figure 4 The high-entropy sulfide prepared in Example 1 was analyzed by scanning electron microscopy and energy dispersive spectroscopy. The results are shown in the figure. Figure 5 ,from Figure 4 It can be seen that the characteristic peak of the product obtained in Example 1 is 382.5 cm⁻¹. -1 and 408.5cm -1 The corresponding 2H phase crystal structure indicates that the high-entropy sulfide obtained in Example 1 is a single phase. Figure 5 It can be seen that the molybdenum, tantalum, vanadium, tungsten, titanium and sulfur elements are evenly distributed in the high-entropy sulfide prepared in Example 1, and no element segregation phenomenon is observed.

[0059] It should be noted that the high-entropy sulfide prepared in this invention is a two-dimensional thin film material, which has a weak signal when XRD is performed, and therefore cannot be characterized by XRD.

[0060] The field-effect transistors (FETs) in the corresponding use cases were tested for their output characteristics under both dark conditions and under 405nm laser irradiation conditions. The results are shown in [reference needed]. Figure 6 ,from Figure 6 It can be seen that the high-entropy sulfide prepared in Example 1 forms a good ohmic contact with the electrode, and the carrier mobility of the high-entropy sulfide is calculated to be as high as 1200 cm⁻¹. 2 / V·s, the high-entropy sulfide prepared in Example 1 exhibits excellent photoelectric response performance to 405nm wavelength laser.

[0061] It should be noted that, Figure 6 Dark (V) BC The data for the series corresponds to the conditions without light, 405nm (V) BC The data for the series corresponds to laser irradiation conditions with a wavelength of 405nm.

[0062] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and all such changes and modifications will fall within the scope of protection of the present invention.

Claims

1. A method for preparing a high-entropy sulfide, characterized in that, Based on a high-temperature tubular furnace having a first temperature zone, a second temperature zone, and a third temperature zone, including: Step S1: Introduce carrier gas into the high-temperature tubular furnace, place sulfur powder in the first temperature zone, and raise the temperature of the first temperature zone, the second temperature zone, and the third temperature zone to the first temperature, the second temperature, and the third temperature, respectively. Step S2: Place the metal source and the reaction substrate in the second temperature zone and the third temperature zone respectively, maintain for a preset time, and cool the obtained reaction product in liquid nitrogen to obtain a high-entropy sulfide. The metal source is composed of a mixture of molybdenum trioxide, tantalum pentoxide, vanadium dioxide, tungsten trioxide, and titanium dioxide. The first temperature zone, the second temperature zone, and the third temperature zone are arranged sequentially along the flow direction of the carrier gas. The first temperature is 300-350℃, the second temperature is 850-950℃, and the third temperature is 1050-1100℃. In the metal source, the mass ratio of molybdenum trioxide, tantalum pentoxide, vanadium dioxide, tungsten trioxide, and titanium dioxide is (4-6):(0.9-1.1):(0.9-1.1):(4-6):

1.

2. The method for preparing high-entropy sulfides according to claim 1, characterized in that, The mass ratio of the sulfur powder to the metal source is (4-6):

1.

3. The method for preparing high-entropy sulfides according to claim 1, characterized in that, In step S2, the preset time is 15-30 minutes.

4. The method for preparing high-entropy sulfides according to claim 1, characterized in that, In step S1, the carrier gas is nitrogen.

5. The method for preparing high-entropy sulfides according to claim 1, characterized in that, The flow rate of the carrier gas is 35-55 sccm.

6. The method for preparing high-entropy sulfides according to claim 1, characterized in that, In step S2, the material of the reaction substrate includes one of sapphire, silicon, and aluminum nitride.

7. The method for preparing high-entropy sulfides according to claim 6, characterized in that, The reaction substrate is made of sapphire.

8. A high-entropy sulfide, characterized in that, It is prepared by the method for preparing high-entropy sulfides as described in any one of claims 1-7.

9. An application of the high-entropy sulfide as described in claim 8 in the field of optoelectronic technology.

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