A method for preparing germanium diselenide

Abstract

The application discloses a preparation method of germanium diselenide and belongs to the technical field of compound preparation. The preparation method of germanium diselenide provided by the application comprises the following steps: mixing germanium powder screened and selenium powder screened and ball milling, then heating and reacting in an inert gas environment, crushing after removing the surface attachments of the heating and reaction product, and heat-insulating and reacting in the inert gas environment, so that golden yellow crystalline germanium diselenide can be obtained. The obtained germanium diselenide is high in purity, free of segregation, and low in loss, namely, high in yield. Moreover, the preparation method provided by the application is simple in operation, does not need special equipment, and is beneficial to practical production and application.

Description

Technical Field

[0001] This invention belongs to the field of compound preparation technology, and particularly relates to a method for preparing germanium diselenide. Background Technology

[0002] Germanium diselenide, as a semiconductor material, has a small bandgap and responds to both visible and infrared light. It typically exhibits a layered structure and is widely used in infrared photoelectric detection. Germanium diselenide is generally synthesized from germanium powder and selenium powder in a solid-state process. However, while the melting point of germanium diselenide is 707℃, it actually begins to sublimate significantly at 530℃. Therefore, currently available germanium diselenide is prone to loss during actual synthesis, resulting in waste. Furthermore, germanium, as a rare metal, is becoming increasingly expensive. The patent "A Method for Preparing Germanium Diselenide Powder" discloses a method for synthesizing germanium diselenide in a vacuum furnace for 10 hours, but this method suffers from a high loss rate, is prone to segregation, and is both costly and time-consuming. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for preparing germanium diselenide that is free from segregation, has a high synthesis yield, and high purity.

[0004] To achieve the above objectives, the technical solution provided by the present invention is as follows: The present invention provides a method for preparing germanium diselenide, the preparation method comprising the following steps:

[0005] (1) Mix the sieved germanium powder and the sieved selenium powder and ball mill them to obtain the ball-milled mixture;

[0006] (2) The ball-milled mixture is heated in an inert gas environment to react and obtain the heating reaction product;

[0007] (3) After removing the surface deposits of the heated reaction product, crush it and keep the crushed material in an inert gas environment for a heat-preserving reaction. After the heat-preserving reaction is completed, germanium diselenide is obtained.

[0008] In the preparation method of germanium diselenide provided by the present invention, sieved germanium powder and sieved selenium powder are mixed and ball-milled, then heated and reacted in an inert gas environment. After removing the surface adhering substances of the heated reaction product, the product is crushed and the crushed product is kept at a constant temperature in an inert gas environment to obtain golden yellow crystalline germanium diselenide. The obtained germanium diselenide has high purity and no segregation, and the loss of germanium diselenide is small, that is, the yield is high.

[0009] As a preferred embodiment of the preparation method of the present invention, the sieving of germanium powder in step (1) includes the following steps: first, the germanium powder is passed through a 55-70 mesh sieve and the sieve material is collected; then, the sieve material is passed through a 150-200 mesh sieve and the sieve material is collected to obtain the sieved germanium powder.

[0010] The sieving of selenium powder includes the following steps: passing the selenium powder through a 150-200 mesh sieve, collecting the sieved material, and obtaining the sieved selenium powder.

[0011] This invention has discovered that, during the reaction process using selenium powder and germanium powder as raw materials, the particle size ratio of selenium powder and germanium powder can control the local proportion of selenium powder and germanium powder during the reaction at the microscopic level. The selenium powder and germanium powder obtained under the sieving conditions given in this invention can reduce the voids during the reaction, thereby allowing the reaction to proceed toward the theoretically synthesized product germanium diselenide, which in turn can reduce segregation and improve the yield.

[0012] In a preferred embodiment of the preparation method of the present invention, in step (1), the mass percentage of the sieved selenium powder is 68-70% based on the total mass of the sieved germanium powder and the sieved selenium powder.

[0013] The present invention has found that controlling the mass ratio of sieved selenium powder in the reactants to 68-70% ensures that the appropriate excess of selenium powder can compensate for the selenium content lost during the preparation process, ensuring that the reaction proceeds according to the stoichiometric ratio, thereby reducing segregation and increasing the yield.

[0014] As a preferred embodiment of the preparation method of the present invention, in step (1), the ball milling process is as follows: zirconium balls are added to sieved germanium powder and sieved selenium powder, then inert gas is introduced and sealed, and then ball milling is performed at a speed of 50-70 r / min for 4-6 h. After the ball milling is completed, the zirconium balls are removed to obtain the ball-milled mixture.

[0015] Preferably, the inert gas is argon; the inert gas is introduced for 10-20 minutes.

[0016] Preferably, the amount of zirconium balls added is 40-60% based on the sieved selenium powder and sieved germanium powder.

[0017] Preferably, the diameter of the zirconium sphere is 4-6 mm.

[0018] Adding sieved germanium powder and sieved selenium powder to zirconium balls for mixing and ball milling can achieve better homogenization, thereby helping to improve the yield of subsequent reactions and reduce segregation.

[0019] As a preferred embodiment of the preparation method of the present invention, in step (2), the heating reaction process is as follows: in an inert gas environment, the temperature is first raised to 150-220℃ at a heating rate of 5-10℃ / min and held for 1-2 hours, then the temperature is raised to 480-550℃ at a heating rate of 5-10℃ / min and held for 2-4 hours, and then the temperature is lowered to room temperature to obtain the heating reaction product.

[0020] This invention has discovered that the heating process and holding temperature during the reaction of selenium powder and germanium powder affect the purity and yield of the product. Previous studies have shown that different reaction temperatures produce products of different colors. For example, synthesis temperatures of 450℃, 500℃, 550℃, and 600℃ produce black germanium selenide, orange-yellow crystalline germanium diselenide, red-yellow loose powder germanium diselenide, and a mixture of black germanium selenide and germanium diselenide, respectively. The heating rate also affects the segregation phenomenon of the product. Within the further optimized heating degree, holding temperature, and time range of this invention, it is possible to ensure that the obtained product has less segregation, higher purity, and higher yield. If the temperature of the first heating in step (2) is too high, segregation will occur, leading to a decrease in yield and purity. If the temperature of the first heating in step (2) is too low, the chemical reaction cannot be carried out effectively, which will reduce the yield to a certain extent. If the temperature of the second heating in step (2) is too high, the product will have too many impurities, and even germanium diselenide may not be synthesized. If the temperature of the second heating in step (2) is too low, segregation will also occur, leading to a decrease in the purity and yield of the product.

[0021] As a preferred embodiment of the preparation method of the present invention, in step (3), the heat preservation reaction process is as follows: in an inert gas environment, the temperature is raised to 430-530℃ at a heating rate of 5-10℃ / min and kept at that temperature for 3-5h, and then cooled to room temperature to obtain germanium diselenide.

[0022] This invention has revealed that, due to the melting point of selenium (220℃), some free selenium or elemental selenium may volatilize at 480℃ during the initial synthesis process. Furthermore, the synthesized germanium diselenide also experiences mass loss at 530℃ (this point is derived from...). Figure 1 The TGA spectrum of germanium diselenide also shows that in an argon atmosphere, the TGA of germanium diselenide shows weight loss starting at 500-600℃. Inevitably, free selenium will remain in the early synthesis process. Therefore, this invention selects a specific heating rate, holding temperature and holding time to remove free selenium from the product as much as possible, thereby improving the purity of the product. If the holding temperature in step (3) is too low, although it will not have a significant impact on the yield and purity, the free selenium content in the product will show an increasing trend, exceeding 100ppm, thereby reducing the quality of the product. If the holding temperature in step (3) is too high, the synthesized germanium diselenide will be lost, resulting in a decrease in yield.

[0023] In a preferred embodiment of the preparation method of the present invention, in step (2), an inert gas is introduced during the heating reaction, and the flow rate of the inert gas is 0.6-2 L / min.

[0024] In a preferred embodiment of the preparation method of the present invention, in step (3), an inert gas is introduced during the heat preservation reaction, and the flow rate of the inert gas is 3-5 L / min.

[0025] This invention has found that controlling the flow rate of inert gas during the heating or heat preservation reaction within the aforementioned range can help achieve excellent product purity.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] This invention provides a method for preparing germanium diselenide, in which sieved germanium powder and sieved selenium powder are mixed and ball-milled, then heated and reacted in an inert gas environment. After removing the surface deposits of the heated reaction product, it is crushed, and the crushed material is kept at a constant temperature in an inert gas environment to obtain golden-yellow crystalline germanium diselenide. The obtained germanium diselenide has high purity, no segregation, and minimal loss, i.e., high yield. Specifically, the purity of the obtained germanium diselenide is above 4.5N, the yield is above 98.66%, and the free selenium content is below 100ppm. Furthermore, the preparation method provided by this invention is simple to operate, requires no special equipment, and is beneficial for practical production applications. Attached Figure Description

[0028] Figure 1 TGA image of germanium diselenide;

[0029] Figure 2 The XRD pattern of the product prepared in Example 1;

[0030] Figure 3 The XRD pattern of the product prepared in Example 2;

[0031] Figure 4 The XRD pattern of the product prepared in Example 3;

[0032] Figure 5 The XRD pattern of the product prepared in Comparative Example 1 is shown.

[0033] Figure 6 The XRD pattern of the product prepared in Comparative Example 2 is shown.

[0034] Figure 7 The XRD pattern of the product prepared in Comparative Example 5 is shown.

[0035] Figure 8 The XRD pattern of the product prepared in Comparative Example 6 is shown.

[0036] Figure 9 The image shows the XRD pattern of the product prepared in Comparative Example 9. Detailed Implementation

[0037] To better illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0038] Unless otherwise specified, the raw materials used in this invention are conventional commercially available raw materials, and the raw materials used in the parallel embodiments or comparative examples of this invention are the same.

[0039] Example 1

[0040] This invention provides germanium diselenide, the preparation method of which includes the following steps:

[0041] (1) Crush germanium particles with a diameter of 3-6 mm (purity of 4N), pass them through a 60-mesh sieve, collect the sieve material, then pass the sieve material through a 150-mesh sieve, collect the sieve material, and obtain the sieved germanium powder.

[0042] (2) Pass the selenium powder through a 150-mesh sieve, collect the sieved material, and obtain the sieved selenium powder.

[0043] (3) Weigh 667g of sieved selenium powder, 300g of sieved germanium powder and 450g of zirconium balls with a diameter of 5mm and put them into a ball mill (based on the sieved selenium powder and sieved germanium powder, the mass percentage of sieved selenium powder is 69.0% and the amount of zirconium balls added is 46.5%), pass argon gas into the ball mill for 15min, then seal it, and then ball mill at a speed of 50r / min for 4h. Then remove the zirconium balls to obtain the ball-milled mixture.

[0044] (4) After ball milling, the mixture is placed into a quartz crucible, covered, and sent into a tube furnace. Nitrogen gas is turned on and the flow rate is set to 0.6 L / min. Then the temperature is raised. First, the temperature is raised to 200℃ at a rate of 5℃ / min and held for 1 h. Then, the temperature is raised to 480℃ at a rate of 5℃ / min and held for 2 h. Then the temperature is lowered to 300℃. Then the furnace is opened to dissipate heat and cool down to room temperature. The product of the heated reaction is then taken out.

[0045] (5) Use a molybdenum sheet to scrape off the orange-yellow powdery material around the heated reaction product, and at the same time use a molybdenum sheet to remove the honeycomb-shaped black, red, and orange-yellow adhering material on the top surface. Then crush it with a tungsten carbide hammer to obtain the crushed material.

[0046] (6) The crushed material is loaded into a quartz boat and sent into a tubular furnace. Nitrogen gas is turned on and the nitrogen flow rate is set to 5L / min. Then the temperature is raised to 480℃ at a rate of 5℃ / min and held for 4h. Then the temperature is lowered to room temperature and taken out to obtain germanium diselenide.

[0047] Example 2

[0048] This invention provides germanium diselenide, the preparation method of which includes the following steps:

[0049] (1) Crush germanium particles with a diameter of 3-6 mm (purity of 4N), pass them through a 70-mesh sieve, collect the sieve material, then pass the sieve material through a 200-mesh sieve, collect the sieve material, and obtain the sieved germanium powder.

[0050] (2) Pass the selenium powder through a 200-mesh sieve, collect the sieved material, and obtain the sieved selenium powder;

[0051] (3) Weigh 822g of sieved selenium powder, 378g of sieved germanium powder and 600g of zirconium balls with a diameter of 5mm and put them into a ball mill (based on the sieved selenium powder and sieved germanium powder, the mass percentage of sieved selenium powder is 68.5% and the amount of zirconium balls added is 50.0%), pass argon gas into the ball mill for 15min, then seal it, and then ball mill at a speed of 50r / min for 4h. Then remove the zirconium balls to obtain the ball-milled mixture.

[0052] (4) After ball milling, the mixture is placed into a quartz crucible, covered, and sent into a tube furnace. Nitrogen gas is turned on and the flow rate is set to 0.6 L / min. Then the temperature is raised. First, the temperature is raised to 200℃ at a rate of 10℃ / min and held for 1 hour. Then, the temperature is raised to 500℃ at a rate of 10℃ / min and held for 2 hours. Then, the temperature is lowered to 300℃. Then, the furnace is opened to dissipate heat and cool down to room temperature. The product of the heated reaction is then taken out.

[0053] (5) Use a molybdenum sheet to scrape off the orange-yellow powdery material around the heated reaction product, and at the same time use a molybdenum sheet to remove the honeycomb-shaped black, red, and orange-yellow adhering material on the top surface. Then crush it with a tungsten carbide hammer to obtain the crushed material.

[0054] (6) The crushed material is loaded into a quartz boat and sent into a tubular furnace. Nitrogen gas is turned on and the nitrogen flow rate is set to 5L / min. Then the temperature is raised to 480℃ at a rate of 10℃ / min and held for 4h. Then the temperature is lowered to room temperature and taken out to obtain germanium diselenide.

[0055] Example 3

[0056] This invention provides germanium diselenide, the preparation method of which includes the following steps:

[0057] (1) Crush germanium particles with a diameter of 3-6 mm (purity of 4N), pass them through a 55-mesh sieve, collect the sieve material, then pass the sieve material through a 180-mesh sieve, collect the sieve material, and obtain the sieved germanium powder.

[0058] (2) Pass the selenium powder through a 180-mesh sieve, collect the sieved material, and obtain the sieved selenium powder.

[0059] (3) Weigh 560g of sieved selenium powder, 240g of sieved germanium powder and 400g of zirconium balls with a diameter of 5mm and put them into a ball mill (based on the sieved selenium powder and sieved germanium powder, the mass percentage of sieved selenium powder is 70.0% and the amount of zirconium balls added is 50.0%), pass argon gas into the ball mill for 15min, then seal it, and then ball mill at a speed of 50r / min for 4h. Then remove the zirconium balls to obtain the ball-milled mixture.

[0060] (4) After ball milling, the mixture is placed into a quartz crucible, covered, and sent into a tube furnace. Nitrogen gas is turned on and the flow rate is set to 0.6 L / min. Then the temperature is raised. First, the temperature is raised to 200℃ at a rate of 8℃ / min and held for 1 h. Then, the temperature is raised to 550℃ at a rate of 8℃ / min and held for 3 h. Then the temperature is lowered to 300℃. Then the furnace is opened to dissipate heat and cool down to room temperature. The product of the heated reaction is then taken out.

[0061] (5) Use a molybdenum sheet to scrape off the orange-yellow powdery material around the heated reaction product, and at the same time use a molybdenum sheet to remove the honeycomb-shaped black, red, and orange-yellow adhering material on the top surface. Then crush it with a tungsten carbide hammer to obtain the crushed material.

[0062] (6) The crushed material is loaded into a quartz boat and sent into a tubular furnace. Nitrogen gas is turned on and the nitrogen flow rate is set to 5L / min. Then the temperature is raised to 480℃ at a rate of 8℃ / min and held for 4h. Then the temperature is lowered to room temperature and taken out to obtain germanium diselenide.

[0063] Example 4

[0064] This embodiment of the invention provides germanium diselenide, the only difference between the preparation method of germanium diselenide and that of Embodiment 1 is step (6), which is as follows:

[0065] The crushed material was loaded into a quartz boat and sent into a tubular furnace. Nitrogen gas was turned on and the flow rate was set to 5 L / min. Then the temperature was raised to 430°C at a rate of 5°C / min and held for 4 hours. The temperature was then lowered to room temperature and removed to obtain germanium diselenide.

[0066] Example 5

[0067] This invention provides a germanium diselenide preparation method, the only difference between this method and that of Example 1 is step (4). Step (4) in this embodiment is as follows:

[0068] The ball-milled mixture was placed into a quartz crucible, covered, and sent into a tube furnace. Nitrogen gas was turned on and the flow rate was set to 0.6 L / min. The temperature was then raised to 150 °C at a rate of 5 °C / min and held for 1 hour. Then the temperature was raised to 480 °C at a rate of 5 °C / min and held for 2 hours. The temperature was then lowered to 300 °C. The furnace was then opened to allow the mixture to cool down to room temperature. The product was then removed and the heated reaction product was obtained.

[0069] Comparative Example 1

[0070] The present invention provides a comparative example of germanium diselenide, the only difference between the preparation method of germanium diselenide and that of Example 1 is step (4). Step (4) of this comparative example is as follows:

[0071] The ball-milled mixture was placed into a quartz crucible, covered, and sent into a tube furnace. Nitrogen gas was turned on and the flow rate was set to 0.6 L / min. The temperature was then raised to 200 °C at a rate of 5 °C / min and held for 1 hour. Then the temperature was raised to 450 °C at a rate of 5 °C / min and held for 2 hours. The temperature was then lowered to 300 °C. The furnace was then opened to allow the mixture to cool down to room temperature. The product was then removed and the heated reaction product was obtained.

[0072] Comparative Example 2

[0073] The present invention provides a comparative example of germanium diselenide, the only difference between the preparation method of germanium diselenide and that of Example 1 is step (4). Step (4) of this comparative example is as follows:

[0074] The ball-milled mixture was placed into a quartz crucible, covered, and sent into a tube furnace. Nitrogen gas was turned on and the flow rate was set to 0.6 L / min. The temperature was then raised to 200°C at a rate of 5°C / min and held for 1 hour. Then the temperature was raised to 600°C at a rate of 5°C / min and held for 2 hours. The temperature was then lowered to 300°C. The furnace was then opened to allow the mixture to cool down to room temperature. The product was then removed and the heated reaction product was obtained.

[0075] Comparative Example 3

[0076] The present invention provides a comparative example of germanium diselenide, the only difference between the preparation method of germanium diselenide and that of Example 1 is step (4). Step (4) of this comparative example is as follows:

[0077] The ball-milled mixture was placed into a quartz crucible, covered, and sent into a tube furnace. Nitrogen gas was turned on and the flow rate was set to 0.6 L / min. The temperature was then raised to 250 °C at a rate of 5 °C / min and held for 1 hour. Then the temperature was raised to 480 °C at a rate of 5 °C / min and held for 2 hours. The temperature was then lowered to 300 °C. The furnace was then opened to allow the mixture to cool down to room temperature. The product was then removed and the heated reaction product was obtained.

[0078] Comparative Example 4

[0079] The present invention provides a comparative example of germanium diselenide, the only difference between the preparation method of germanium diselenide and that of Example 1 being step (6). Step (6) of this comparative example is as follows:

[0080] The crushed material was loaded into a quartz boat and sent into a tubular furnace. Nitrogen gas was turned on and the flow rate was set to 5 L / min. Then the temperature was raised to 550°C at a rate of 5°C / min and held for 4 hours. The temperature was then lowered to room temperature and removed to obtain germanium diselenide.

[0081] Comparative Example 5

[0082] The present invention provides a germanium diselenide comparative example. The only difference between the preparation method of the germanium diselenide and that of Example 1 is step (3). In step (3) of this comparative example, the mass percentage of the sieved selenium powder is 60% based on the sieved selenium powder and the sieved germanium powder.

[0083] Comparative Example 6

[0084] The present invention provides a germanium diselenide comparative example. The only difference between the preparation method of the germanium diselenide and that of Example 1 is step (3). In step (3) of this comparative example, the mass percentage of the sieved selenium powder is 73%, based on the sieved selenium powder and the sieved germanium powder.

[0085] Comparative Example 7

[0086] The present invention provides a comparative example of germanium diselenide, the only difference between the preparation method of germanium diselenide and that of Example 1 being step (1). Step (1) of this comparative example is as follows:

[0087] Germanium particles with a diameter of 3-6 mm (purity of 4N) are crushed and passed through a 20-mesh sieve. The undersize material is collected, and then the undersize material is passed through a 150-mesh sieve. The oversize material is collected to obtain sieved germanium powder.

[0088] Comparative Example 8

[0089] The present invention provides a comparative example of germanium diselenide, the only difference between the preparation method of germanium diselenide and that of Example 1 being step (1). Step (1) of this comparative example is as follows:

[0090] Germanium particles with a diameter of 3-6 mm (purity of 4N) are crushed, passed through a 60-mesh sieve, and the undersize is collected. Then, the undersize is passed through a 300-mesh sieve, and the oversize is collected to obtain sieved germanium powder.

[0091] Comparative Example 9

[0092] The present invention provides a comparative example of germanium diselenide, the only difference between the preparation method of germanium diselenide and that of Example 1 being step (1). Step (1) of this comparative example is as follows:

[0093] Germanium particles with a diameter of 3-6 mm (purity of 4N) are crushed and passed through a 10-mesh sieve. The undersize material is collected, and then the undersize material is passed through a 325-mesh sieve. The oversize material is collected to obtain sieved germanium powder.

[0094] Example of effect

[0095] The effectiveness examples of this invention verify the performance and yield of germanium diselenide prepared in Examples 1-5 and Comparative Examples 1-9, including the following aspects:

[0096] 1. Segregation phenomenon: The prepared germanium diselenide was subjected to XRD detection and compared with the standard card. If there were no other impurity diffraction peaks, it was recorded as no segregation; if there were other diffraction peaks, it was recorded as segregation.

[0097] 2. Purity: The product prepared by XRD is tested, and the content of germanium diselenide is calculated based on the peak values ​​of germanium diselenide and germanium selenide. The content of heteroatoms in the product is tested by ICP-OES. Finally, the content of germanium diselenide in the whole product is calculated, which is the purity.

[0098] 3. Yield: The yield is calculated as the percentage of the actual mass of germanium diselenide obtained to the theoretical mass of the input raw materials.

[0099] The results are shown in Table 1; in Table 1, if the purity obtained from the actual test is above 99.995%, it is recorded as 100% purity.

[0100] Table 1

[0101] Segregation purity / % Yield / % Segregation purity / % Yield / % Example 1 none 100 98.66 Comparative Example 3 have 60.46 48.23 Example 2 none 100 99.01 Comparative Example 4 none 100 70.13 Example 3 none 100 99.84 Comparative Example 5 have 0 0 Example 4 none 100 99.69 Comparative Example 6 have 0 0 Example 5 none 100 98.43 Comparative Example 7 have 6.56 1.83 Comparative Example 1 have 98.21 96.14 Comparative Example 8 have 10.21 2.18 Comparative Example 2 have 0 0 Comparative Example 9 have 90.15 81.12

[0102] The elemental contents of germanium diselenide prepared in Examples 1 and 5 were further recorded, and the results are shown in Tables 2 and 3, respectively.

[0103] Table 2. Element content of the product prepared in Example 1 (unit: ppm)

[0104]

[0105]

[0106] Table 3. Element content of the product prepared in Example 5 (unit: ppm)

[0107] element Na Mg Al Ca Cr Mn Pb content ＜1 ＜1 ＜1 ＜3 ＜1 2 ＜1 element Fe Co Ni Cu Zn As Bi content 9 ＜1 ＜1 2 1 ＜3 ＜1 element Ag Sn Sb Te Hg Ti Si content ＜1 ＜1 ＜1 3 ＜1 ＜1 ＜3

[0108] As can be seen from Table 1, when the technical solution of the present invention is adopted, the obtained germanium diselenide has no segregation, high purity, and high yield. Specifically, the purity is above 99.5%, specifically above 4.5N, and the yield is above 98.43%. Furthermore, the content of impurities in the prepared product is below 9 ppm. Meanwhile, the products prepared in Examples 1-5 are crystalline, and the free selenium in them meets the product requirements, being below 100 ppm.

[0109] In addition, the XRD patterns of germanium diselenide prepared in Examples 1-3 are as follows: Figure 2-4 As stated, from Figure 2-4 As can be seen from the XRD pattern, the germanium diselenide prepared in Examples 1-2 corresponds only to diffraction peaks #42-1104 in the standard card, with no other impurity peaks; the germanium diselenide prepared in Example 3 corresponds only to diffraction peaks #71-01174 in the standard card, with no other impurity peaks; while the XRD pattern of the product prepared in Comparative Example 1 ( Figure 5 As can be seen from the image, the product corresponds to the diffraction peaks in both sets of standard cards, namely #48-1226 and #42-1104. The XRD pattern of the product prepared in Comparative Example 2 is shown in the image. Figure 6 Although it only corresponds to one diffraction peak, it corresponds to the standard card diffraction peak #48-1226 of germanium selenide. The XRD pattern of the product prepared in Comparative Example 5 is shown in the figure. Figure 7 Although it only corresponds to one diffraction peak, it corresponds to the standard card diffraction peak #48-1226 of germanium selenide. The XRD pattern of the product prepared in Comparative Example 6 is shown in the figure. Figure 8 In the example 9, due to excessive selenium powder addition, the XRD pattern of the obtained product had many impurity peaks, and the diffraction peak corresponding to germanium diselenide could not be found in the spectrum. Figure 9 The peaks in the image correspond to diffraction peaks in two sets of standard cards, namely germanium selenide #48-1226 and germanium diselenide #30-595; that is, from... Figure 2-9 It can also be seen that the technical solution of the present invention can obtain the target product germanium diselenide, and the prepared germanium diselenide has no segregation.

[0110] As can be seen from Example 1 and Comparative Example 1, when the holding temperature in the later stage of the synthesis process is too low, the obtained product will exhibit segregation, and the purity and yield of the obtained product show a significant downward trend. As can be seen from Example 1 and Comparative Example 2, when the holding temperature in the later stage of the synthesis process is too high, the obtained product is germanium selenide, not germanium diselenide, and therefore the yield is 0. As can be seen from Example 1, Example 5 and Comparative Example 3, the holding temperature in the early stage of the synthesis process also has a certain impact on the purity and yield of the product. When the holding temperature in the early stage of the synthesis process is not within the range given in this invention, the purity and yield decrease significantly compared with Example 1. Specifically, the purity in Comparative Example 3 decreased by 39.51% and the yield decreased by 50.43%.

[0111] As can be seen from Examples 1, 4 and Comparative Example 4, the temperature during the crushing and selenium removal process after the synthesis reaction also affects the yield and purity of the product. When the temperature is too high during the crushing and selenium removal process after the synthesis reaction in Comparative Example 4, the yield will decrease. Compared with Example 1, the yield in Comparative Example 4 decreased by 28.53%.

[0112] As can be seen from Example 1 and Comparative Examples 5-6, when the mass percentage of selenium powder during the reaction is not within the range of the present invention, the corresponding germanium diselenide product cannot be synthesized.

[0113] As can be seen from Example 1 and Comparative Examples 7-9, when the mesh size of the germanium powder is not within the range given in this invention, it will not only affect the segregation phenomenon of the product, but also affect the purity and yield of the product.

[0114] Finally, it should be noted that the above embodiments are used to illustrate the technical solutions of the present invention and not to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for preparing germanium diselenide, characterized in that, The preparation method includes the following steps: (1) Mix the sieved germanium powder and the sieved selenium powder and ball mill them to obtain the ball-milled mixture; (2) The ball-milled mixture is heated in an inert gas environment to react and obtain the heating reaction product; (3) After removing the surface residue of the heated reaction product, crush it and keep the crushed product in an inert gas environment for heat preservation reaction. After the heat preservation reaction is completed, germanium diselenide is obtained. In step (1), the sieving of germanium powder includes the following steps: first, pass the germanium powder through a 55-70 mesh sieve and collect the sieve material; then, pass the sieve material through a 150-200 mesh sieve and collect the sieve material to obtain sieved germanium powder. The sieving of selenium powder includes the following steps: passing the selenium powder through a 150-200 mesh sieve, collecting the sieved material, and obtaining the sieved selenium powder. In step (1), the total mass of the sieved germanium powder and the sieved selenium powder is 68-70% by mass. In step (2), the heating reaction process is as follows: in an inert gas environment, the temperature is first raised to 150-220℃ at a heating rate of 5-10℃ / min and held for 1-2 hours, then the temperature is raised to 480-550℃ at a heating rate of 5-10℃ / min and held for 2-4 hours, and then the temperature is lowered to room temperature to obtain the heating reaction product. In step (3), the heat preservation reaction process is as follows: in an inert gas environment, the temperature is raised to 430-530℃ at a heating rate of 5-10℃ / min and kept at that temperature for 3-5 hours, and then cooled to room temperature to obtain germanium diselenide.

2. The preparation method according to claim 1, characterized in that, In step (1), the ball milling process is as follows: zirconium balls are added to sieved germanium powder and sieved selenium powder, then inert gas is introduced and sealed, and then ball milling is carried out at a speed of 50-70 r / min for 4-6 hours. After the ball milling is completed, the zirconium balls are removed to obtain the ball-milled mixture.

3. The preparation method according to claim 1, characterized in that, In step (2), an inert gas is introduced during the heating reaction, and the flow rate of the inert gas is 0.6-2 L / min.

4. The preparation method according to claim 1, characterized in that, In step (3), an inert gas is introduced during the heat preservation reaction, and the flow rate of the inert gas is 3-5 L / min.

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