Lithium fluoride nanowire as well as preparation method and application thereof

Abstract

The invention provides a lithium fluoride nanowire as well as a preparation method and application thereof. The lithium fluoride nanowire is prepared by adopting a high-temperature solid gas phase method, specifically, a tubular furnace is heated to evaporate lithium fluoride powder and zinc telluride powder and convey the evaporated lithium fluoride powder and zinc telluride powder to the downstream through flowing argon, after the reaction time is over, cooling is carried out, introduction of argon is stopped, and after the high-temperature furnace is naturally cooled, the lithium fluoride nanowire is obtained on a base material; in the heating process, the zinc telluride powder is decomposed to generate zinc steam, then the zinc steam is condensed to form zinc liquid drops, under the condition that the zinc liquid drops serve as a catalyst, saturated fluorine and lithium are continuously separated out, and the lithium fluoride square column-shaped nanowire is formed. Continuously conveyed new zinc liquid drips on the surface of the nanowire to form new growing points, so that a lithium fluoride nanowire three-dimensional structure with a vertical relation grows; the preparation method disclosed by the invention is simple in process, the lithium fluoride nanowire is regular in structure, and the obtained nanowire has a specific crystal orientation and a three-dimensional structure and can be used for researching a room-temperature color center laser.

Description

Technical Field

[0001] This invention belongs to the field of nanomaterial preparation, and particularly relates to a lithium fluoride nanowire, its preparation method and application. Background Technology

[0002] Color center lasers are a new type of laser, attracting increasing attention and experiencing rapid development in recent years due to their superior characteristics such as high efficiency, high output power, low pump threshold, narrow linewidth, and tunable wavelength. Among them, lithium fluoride crystals have been the most studied material for color center lasers because they have the highest photothermal stability of color centers among alkali halide crystals and can easily achieve laser operation at room temperature.

[0003] Currently available lithium fluoride nanomaterials are mostly prepared by liquid-phase methods and template methods, but they have the following drawbacks: The products are mostly one-dimensional nanowires or amorphous powders, making it difficult to form three-dimensional controllable structures. Summary of the Invention

[0004] To address the shortcomings of the prior art, this invention provides lithium fluoride nanowires, their preparation method, and applications. The preparation method of this invention is simple, produces lithium fluoride nanowires with a regular structure, and the resulting nanowires possess specific crystal orientations and three-dimensional structures, making them suitable for research on room-temperature color center lasers.

[0005] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a method for preparing lithium fluoride nanowires, comprising the following steps: Lithium fluoride powder and zinc telluride powder are mixed and placed in a tube furnace; The substrate is placed inside a tube furnace and downstream of lithium fluoride powder and zinc telluride powder; Argon gas is introduced into a tube furnace and the furnace is heated so that lithium fluoride powder and zinc telluride powder are evaporated and transported downstream by flowing argon gas to form lithium fluoride nanowires on a substrate.

[0006] Preferably, argon gas is introduced into the tube furnace, and the tube furnace is heated to 850~860°C so that lithium fluoride powder and zinc telluride powder are evaporated and transported downstream by flowing argon gas to form lithium fluoride nanowires on the substrate.

[0007] Preferably, after evacuating the tubular furnace, argon gas with a flow rate of 150~160 sccm is introduced into the tubular furnace to make the pressure inside the tubular furnace 500~520 Torr. The tubular furnace is then heated to 850~860℃, the pressure is adjusted to 300~320 Torr, and maintained for 2~3 hours to generate lithium fluoride nanowires on the substrate.

[0008] Preferably, the tubular furnace is heated to 850-860°C at a rate of 20-22°C / min.

[0009] Preferably, the mass ratio of lithium fluoride powder to zinc telluride powder is (1~2):(1~2).

[0010] Preferably, the method for preparing the zinc telluride powder includes the following steps: Zinc powder and tellurium powder are mixed and calcined under an inert atmosphere to obtain zinc telluride powder.

[0011] Preferably, in the step of calcining the zinc powder and tellurium powder under an inert atmosphere, the calcination temperature is 500~520℃ and the time is 20~30min.

[0012] Secondly, the present invention also provides a lithium fluoride nanowire, which is prepared by the aforementioned preparation method.

[0013] Preferably, the lithium fluoride nanowires have a diameter of 100~500nm and a length of <10μm.

[0014] Thirdly, the present invention also provides the application of the aforementioned lithium fluoride nanoparticles in the preparation of color center lasers.

[0015] The method for preparing lithium fluoride nanowires of the present invention has the following advantages over the prior art: This invention employs a high-temperature solid-state vapor phase method to prepare lithium fluoride nanowires. Specifically, a tube furnace is heated to evaporate lithium fluoride powder and zinc telluride powder, which are then transported downstream by flowing argon gas. After the reaction time is complete, the temperature is lowered and the argon gas supply is stopped. After the high-temperature furnace cools naturally, lithium fluoride nanowires are obtained on a substrate. During heating, zinc telluride powder decomposes to generate zinc vapor, which then condenses to form zinc droplets. Under the condition that the zinc droplets act as a catalyst, saturated fluorine and lithium continuously precipitate, forming lithium fluoride prismatic nanowires. Simultaneously, new zinc droplets continuously flow onto the nanowire surface, forming new growth points, thereby growing a three-dimensional lithium fluoride nanowire structure with a perpendicular relationship. The lithium fluoride nanowires have a diameter of 100 to 500 nanometers and a length slightly less than 10 micrometers, and their growth direction is cubic. <001> The direction and growth mechanism conform to the vapor-liquid-solid (VLS) growth model with zinc droplets as catalysts. The preparation method of this invention is simple, the lithium fluoride nanowires have regular structures, and the obtained nanowires have specific crystal orientations and three-dimensional structures, which can be used for the research of room temperature color center lasers. Attached Figure Description

[0016] The above and other objects, features, and advantages of exemplary embodiments of the present disclosure will become readily apparent upon reading the following detailed description with reference to the accompanying drawings. In the drawings, several embodiments of the present disclosure are illustrated by way of example and not limitation, and like or corresponding reference numerals denote like or corresponding parts, wherein: Figure 1 This is a scanning electron microscope image of the lithium fluoride nanowires prepared in Example 1 of this invention; Figure 2 This is a schematic diagram of the lithium fluoride nanowire growth process of the present invention. Detailed Implementation

[0017] The technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0018] The specific embodiments of this disclosure will now be described in detail with reference to the accompanying drawings.

[0019] It should be noted that the order of description of the following embodiments is not intended to limit the preferred order of embodiments. Furthermore, in the description of this application, the term "comprising" means "including but not limited to". Various embodiments of the present invention may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a rigid limitation on the scope of the invention; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single digits within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Additionally, whenever a numerical range is indicated herein, it means including any referenced number (fraction or integer) within the indicated range.

[0020] While various embodiments of the invention have been shown and described herein, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. Many modifications, alterations, and alternatives will occur to those skilled in the art without departing from the spirit and essence of the invention. It should be understood that various alternatives to the embodiments of the invention described herein may be employed in the practice of the invention. The appended claims are intended to define the scope of protection of the invention and therefore cover modular compositions, equivalents, or alternatives within the scope of these claims.

[0021] This invention provides a method for preparing lithium fluoride nanowires, comprising the following steps: S1. Mix lithium fluoride powder and zinc telluride powder and place them in a tube furnace. S2. The substrate is placed in a tube furnace downstream of the lithium fluoride powder and zinc telluride powder. S3. Argon gas is introduced into the tube furnace and the tube furnace is heated so that lithium fluoride powder and zinc telluride powder are evaporated and transported downstream by the flowing argon gas to form lithium fluoride nanowires on the substrate.

[0022] This invention utilizes a high-temperature solid-gas phase method to prepare lithium fluoride nanowires under the action of a catalyst. Specifically, a tube furnace is heated to evaporate lithium fluoride powder and zinc telluride powder, which are then transported downstream by flowing argon gas (downstream refers to the area behind the lithium fluoride and zinc telluride powders along the argon gas flow direction). After the reaction time is complete, the temperature is lowered and the argon gas flow is stopped. After the high-temperature furnace cools naturally, lithium fluoride nanowires are obtained on a substrate. During heating, zinc telluride (ZnTe) powder decomposes to generate zinc vapor, and the following reaction occurs: ZnTe → Zn + Te. The zinc vapor mixes with the evaporated lithium fluoride during its transport downstream with the argon gas flow, forming zinc droplets at the alumina substrate in the low-temperature region of the downstream end. Saturated lithium fluoride continuously precipitates from the droplets, growing into lithium fluoride prismatic nanowires. The zinc droplets act as a catalyst. Simultaneously, new zinc droplets fall onto the surface of the already grown nanowire prismatic columns, forming new growth points, thereby growing a three-dimensional lithium fluoride nanowire structure with a vertical relationship. Lithium fluoride nanowires have a diameter of 100 to 500 nanometers and a length of slightly less than 10 micrometers, and their growth direction is cubic. <001> The direction and growth mechanism conform to the vapor-liquid-solid (VLS) growth model with zinc droplets as catalysts.

[0023] This invention produces lithium fluoride nanowires using a high-temperature solid-state vapor phase method. The process is simple, and the resulting nanowires have specific crystal orientations and three-dimensional structures, which can be directly used in the research of room-temperature color center lasers.

[0024] In some embodiments, argon gas is introduced into a tube furnace, and the tube furnace is heated to 850~860°C to evaporate lithium fluoride powder and zinc telluride powder and transport them downstream by flowing argon gas to form lithium fluoride nanowires on a substrate. Since the substrate is located on the lithium fluoride powder and zinc telluride powder, its temperature is lower than 850~860°C, and the substrate temperature is 400~500°C, so the lithium fluoride nanowires are formed on the substrate at 400~500°C.

[0025] In some embodiments, after evacuating the tubular furnace, argon gas with a flow rate of 150-160 sccm is introduced into the tubular furnace to make the pressure inside the tubular furnace 500-520 Torr (1 Torr = 133.322 Pa). The tubular furnace is then heated to 850-860°C, the pressure is adjusted to 300-320 Torr, and maintained for 2-3 hours to deposit lithium fluoride nanowires on the substrate.

[0026] In some embodiments, the tubular furnace is heated from room temperature (20-25°C) to 850-860°C at a rate of 20-22°C / min.

[0027] In some embodiments, the mass ratio of lithium fluoride powder to zinc telluride powder is (1~2):(1~2).

[0028] In some embodiments, the substrate is an alumina substrate.

[0029] In some embodiments, lithium fluoride powder and zinc telluride powder are mixed and placed in an alumina boat-shaped crucible. The alumina boat-shaped crucible is then placed in the middle of a tube furnace. The tube furnace is evacuated to a pressure below 5 Pa. Argon gas with a flow rate of 150-160 sccm is introduced into the tube furnace to make the pressure inside the tube furnace 500-520 Torr. The tube furnace is heated to 850-860°C, and the pressure is adjusted to 300-320 Torr. This is maintained for 2-3 hours to generate lithium fluoride nanowires on a substrate.

[0030] In some embodiments, the substrate is further treated before deposition, specifically by polishing the surface of the substrate, then immersing it in ethanol for ultrasonic cleaning for 10-20 minutes, and then taking it out to air dry naturally.

[0031] In some embodiments, the method for preparing zinc telluride powder includes the following steps: In some embodiments, before deposition, the inner wall of a tubular furnace with a length of 1 meter and a diameter of 60 centimeters is wiped with ethanol three times and then allowed to air dry naturally.

[0032] Zinc powder and tellurium powder are mixed and calcined under an inert atmosphere to obtain zinc telluride powder.

[0033] In some embodiments, after mixing zinc powder and tellurium powder, the step of calcining under an inert atmosphere involves a calcination temperature of 500-520°C and a time of 20-30 minutes.

[0034] In some embodiments, the inert atmosphere includes at least one of nitrogen, helium, neon, and argon.

[0035] In some embodiments, the molar ratio of zinc powder to tellurium powder is 1:1.

[0036] Further reference Figure 2 As shown, Figure 2 In section i, LiF nanowires are grown first. Figure 2 In section ii, liquid zinc catalyst is dripped onto the surface of a LiF nanowire prism; Figure 2 In section iii, under the condition of zinc droplets acting as a catalyst, saturated lithium fluoride is continuously deposited and flows along... <001> Lithium fluoride prismatic nanowires were grown in the crystal direction (i.e., LiF nanowires were grown in the vertical direction). Figure 2 In step iv, new zinc liquid droplets are continuously transported and fall onto the surface of the secondary LiF nanowire (i.e., vertically grown LiF nanowire) square pillars, forming new growth points, and thus growing a three-dimensional structure of lithium fluoride nanowires with a vertical relationship.

[0037] Based on the same inventive concept, the present invention also provides a lithium fluoride nanowire, which is prepared by the aforementioned preparation method.

[0038] In some embodiments, the lithium fluoride nanowires have a diameter of 100~500nm and a length of <10μm.

[0039] Based on the same inventive concept, this invention also provides the application of the aforementioned lithium fluoride nanowires in the fabrication of color center lasers. The lithium fluoride nanowires of this invention have a regular structure, and the resulting nanowires possess specific crystal orientations and three-dimensional structures, making them suitable for research on room-temperature color center lasers.

[0040] The following further describes the preparation method of lithium fluoride nanowires of the present invention. This section further illustrates the content of the present invention with reference to specific embodiments, but should not be construed as limiting the present invention. Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0041] Example 1 This embodiment provides a method for preparing lithium fluoride nanowires, including the following steps: S1. Synthesis of zinc telluride powder: 10g of zinc powder and 19.69g of telluride powder were ground and mixed in an agate mortar at a molar ratio of 1:1. The mixture was then placed in an alumina boat-shaped crucible and placed in a tube furnace. The mixture was reacted at 500℃ for 20min under an argon atmosphere to produce reddish-brown zinc telluride powder. S2. Grind and mix 5g of lithium fluoride powder and 5g of zinc telluride powder in an agate mortar, and then place them in an alumina boat-shaped crucible. S3. Wipe the inner wall of the tubular furnace, which is 1 meter long and 60 centimeters in diameter, with ethanol three times and let it air dry. Polish the surface of the alumina substrate, then immerse it in ethanol for ultrasonic cleaning for 10 minutes and let it air dry. An alumina boat-shaped crucible containing lithium fluoride powder and zinc telluride powder in S2 was placed in the middle of a tube furnace. An alumina substrate was placed in the tube furnace downstream of the crucible. The tube furnace was evacuated to a pressure of 3 Pa. Argon gas was introduced into the tube furnace at a flow rate of 150 sccm to bring the pressure inside the tube furnace to 500 Torr. The tube furnace was heated from room temperature (25 °C) to 850 °C at a rate of 20 °C / min. The pressure was adjusted to 300 Torr and maintained for 2 hours. Under these conditions, the lithium fluoride and zinc telluride powders were evaporated and transported downstream of the vacuum furnace tube by the flowing argon gas. Lithium fluoride nanowires were generated on the alumina substrate.

[0042] Figure 1 This is a scanning electron microscope image of the lithium fluoride nanowires prepared in Example 1.

[0043] from Figure 1 As can be seen, lithium fluoride nanowires are prismatic nanowires with diameters of approximately 100–500 nm and lengths <10 μm. The nanowires exhibit a three-dimensional morphology, with some nanowires growing perpendicularly to the surfaces of others. The small particles attached to the tips of the nanowires are identified as zinc catalysts. The prismatic morphology of the lithium fluoride nanowires indicates that their growth direction is cubic. <001> direction.

[0044] It is understood that the technical features of the above embodiments can be combined arbitrarily. 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.

[0045] The above are merely preferred embodiments of this application, and only specifically describe the technical principles of this application. These descriptions are only for explaining the principles of this application and should not be construed as limiting the scope of protection of this application in any way. Based on this explanation, any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application, as well as other specific embodiments of this application that can be conceived by those skilled in the art without creative effort, should be included within the scope of protection of this application.

Claims

1. A method for preparing lithium fluoride nanowires, characterized in that, Includes the following steps: Lithium fluoride powder and zinc telluride powder are mixed and placed in a tube furnace; The substrate is placed inside a tube furnace and downstream of lithium fluoride powder and zinc telluride powder; Argon gas is introduced into a tube furnace and the furnace is heated so that lithium fluoride powder and zinc telluride powder are evaporated and transported downstream by flowing argon gas to form lithium fluoride nanowires on a substrate.

2. The method for preparing lithium fluoride nanowires as described in claim 1, characterized in that, Argon gas is introduced into a tube furnace, and the furnace is heated to 850~860℃ to evaporate lithium fluoride powder and zinc telluride powder and transport them downstream by flowing argon gas to form lithium fluoride nanowires on a substrate.

3. The method for preparing lithium fluoride nanowires as described in claim 2, characterized in that, After evacuating the tubular furnace, argon gas with a flow rate of 150-160 sccm is introduced into the tubular furnace to make the pressure inside the furnace 500-520 Torr. The tubular furnace is then heated to 850-860℃, and the pressure is adjusted to 300-320 Torr. This pressure is maintained for 2-3 hours to generate lithium fluoride nanowires on the substrate.

4. The method for preparing lithium fluoride nanowires as described in claim 2, characterized in that, The tubular furnace is heated to 850-860℃ at a rate of 20-22℃ / min.

5. The method for preparing lithium fluoride nanowires as described in claim 1, characterized in that, The mass ratio of lithium fluoride powder to zinc telluride powder is (1~2):(1~2).

6. The method for preparing lithium fluoride nanowires as described in claim 1, characterized in that, The method for preparing the zinc telluride powder includes the following steps: Zinc powder and tellurium powder are mixed and calcined under an inert atmosphere to obtain zinc telluride powder.

7. The method for preparing lithium fluoride nanowires as described in claim 6, characterized in that, In the step of calcining the mixture of zinc powder and tellurium powder under an inert atmosphere, the calcination temperature is 500~520℃ and the time is 20~30min.

8. A lithium fluoride nanowire, characterized in that, It is prepared by any one of the preparation methods described in claims 1 to 7.

9. The lithium fluoride nanowire as described in claim 8, characterized in that, The lithium fluoride nanowires have a diameter of 100~500nm and a length of <10μm.

10. The application of lithium fluoride nanowires as described in any one of claims 8 to 9 in the preparation of color center lasers.

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