A layered ternary selenide, a layered ternary selenide single crystal material and a preparation method thereof

Abstract

The invention discloses a layered ternary selenide, a layered ternary selenide single crystal material and a preparation method thereof, and belongs to the technical field of crystal materials. The chemical formula of the layered ternary selenide is In2Ge2Se6, and indium powder, germanium powder and selenium powder with a specific ratio are used as raw materials. The synthesis of the layered ternary selenide In2Ge2Se6 single-phase material is achieved through high-temperature melting, insulation in a specific temperature range and quenching process. The material has a narrow band gap and low thermal conductivity, and its millimeter-level thin-layer nanosheet single crystal material can be prepared by mechanical stripping, which can be applied to semiconductor optoelectronic devices, solar cells, thermoelectric devices and other fields.

Description

Technical Field

[0001] The present invention relates to the technical field of crystal materials, and in particular to a layered ternary selenide, a layered ternary selenide single crystal material and a preparation method thereof. Background Art

[0002] There are many types of layered chalcogenides and they are widely used. These compounds are formed by stacking two-dimensional or quasi-two-dimensional layered units in a certain direction. There are van der Waals interactions between the layers of the units, which makes these materials exhibit unique physical and chemical properties and show great potential for application in the fields of field effect transistors, photodetectors, gas sensors, spin electronics and thermoelectric devices.

[0003] Among them, the layered structure A2M2Q6 (A = In, Sb, Bi, Al, Sc, V, Cr; M = Si, Ge; Q = S, Se, Te) is a new type of material system, and its structure and properties are predicted by theoretical calculations. This type of material has unique Fermi energy state density, low lattice thermal conductivity, low carrier concentration, good kinetic and thermodynamic stability, good ferromagnetic stability, excellent photocatalytic activity and other characteristics. It is worth noting that some of the predicted material systems have been experimentally confirmed, such as Sc2Si2Te6, V2Si2Se6, Cr2Ge2Te6 and In2Ge2Te6. In addition, thin layer nanosheets of this type of material exhibit exotic properties, such as Cr2Ge2Te6 nanosheets showing two-dimensional material properties of the ferromagnetic ground state. For the layered structure In2Ge2Se6 (space group: R ), theoretical calculations predict that it is a semiconductor material with a band gap of about 1.9 eV, and the single-layer In2Ge2Se6 has a low thermal conductivity of about 7.68 Wm at 300 K. -1 .K -1 , which is expected to be used in semiconductor optoelectronic devices, solar cells, thermoelectric devices and other fields, but there is no report on the experimental synthesis of this material.

[0004] It can be seen that the existing technology still needs to be improved and enhanced. Summary of the invention

[0005] The purpose of the present invention is to provide a layered ternary selenide, a layered ternary selenide single crystal material and a preparation method thereof, aiming to solve the problem that there is no technical means to synthesize layered structure In2Ge2Se6 materials in the prior art.

[0006] To achieve the above object, the solution provided by the present invention is:

[0007] The present invention provides a layered ternary selenide, wherein its chemical formula is In2Ge2Se6 and its space group is R .

[0008] A method for preparing a layered ternary selenide single-phase material, wherein the layered ternary selenide is the layered ternary selenide as described above, and the preparation method comprises the following steps:

[0009] S001. Using indium powder, germanium powder and selenium powder in a molar ratio of 2:2:6 as raw materials, heating to 950-1000°C under vacuum conditions, and keeping at this temperature for 12-24h;

[0010] S002. After the insulation is completed, the temperature is lowered to 650-665°C at a cooling rate of 2-5°C / min, and the temperature is kept at 650-665°C for 96-240h. After the insulation is completed, the material is quenched and cooled to room temperature to obtain a layered ternary selenide single-phase material with a chemical formula of In2Ge2Se6.

[0011] In the method for preparing the layered ternary selenide single-phase material, in step S001, the purity of indium powder, germanium powder and selenium powder are all ≥99.99%.

[0012] In the method for preparing the layered ternary selenide single-phase material, in step S001, the vacuum degree of the vacuum condition is ≤1Pa.

[0013] In the method for preparing the layered ternary selenide single-phase material, in step S001, the heating rate is 2-5°C / min.

[0014] The present invention also provides a layered selenium compound single crystal material, wherein the layered ternary selenium compound single crystal material is an In2Ge2Se6 thin layer nanosheet, wherein the In2Ge2Se6 thin layer nanosheet is prepared by mechanical exfoliation of a layered ternary selenide single phase material, and wherein the layered ternary selenide single phase material is prepared by the preparation method of the layered ternary selenide single phase material as described above.

[0015] The In2Ge2Se6 thin layer nanosheet has c Axial layered structure.

[0016] The thickness direction of the In2Ge2Se6 thin-layer nanosheet is the crystallographic direction of the In2Ge2Se6 structure. c Axis orientation.

[0017] Beneficial effects:

[0018] The first aspect of the present invention provides a layered ternary selenide, the chemical formula of which is In2Ge2Se6, by using indium powder, germanium powder and selenium powder in a specific ratio as raw materials, and by high-temperature firing, the indium powder, germanium powder and selenium powder are fully reacted, and then the temperature is cooled to a certain temperature for heat preservation, and finally quenching treatment is performed to obtain a layered ternary selenide single-phase material with a chemical formula of In2Ge2Se6. It has a narrow band gap and low thermal conductivity, and can be applied to the fields of semiconductor optoelectronic devices, solar cells and thermoelectric devices.

[0019] The present invention also provides a layered ternary selenide single crystal material. By mechanically exfoliating the In2Ge2Se6 single-phase material, a large-area single crystal thin layer nanosheet is prepared, providing material for the study of the intrinsic properties of the material and its application in the fields of flexible semiconductor optoelectronic devices and the like. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a photograph of the layered ternary In2Ge2Se6 selenide single-phase material provided in Example 1 taken through an optical microscope.

[0021] Figure 2 This is the X-ray powder diffraction pattern of the layered ternary In2Ge2Se6 selenide single-phase material provided in Example 1.

[0022] Figure 3 This is a scanning electron microscope image of the cross-sectional microstructure of the layered ternary In2Ge2Se6 selenide single-phase material provided in Example 1.

[0023] Figure 4 This is the X-ray energy spectrum of the layered ternary In2Ge2Se6 selenide single-phase material provided in Example 1.

[0024] Figure 5 This is an atomic resolution structure diagram of the layered ternary In2Ge2Se6 selenide single-phase material provided in Example 1 in the [1-100] projection direction.

[0025] Figure 6 This is the UV-visible absorption spectrum of the ternary In2Ge2Se6 selenide single-phase material provided in Example 1.

[0026] Figure 7 It is the thermal conductivity of the ternary In2Ge2Se6 selenide single-phase material provided in Example 1 at different temperatures.

[0027] Figure 8 This is a photograph of the ternary In2Ge2Se6 thin layer nanosheet provided in Example 1 taken through an optical microscope.

[0028] Fig. 9This is the X-ray diffraction pattern of the ternary In2Ge2Se6 thin layer nanosheet provided in Example 1.

[0029] Fig.10 This is the X-ray powder diffraction pattern of the layered ternary In2Ge2Se6 selenide single-phase material provided in Example 2.

[0030] Fig.11 This is the X-ray powder diffraction pattern of the selenide provided in Comparative Examples 1-3.

[0031] Fig.12 This is the X-ray powder diffraction pattern of the selenide provided in Comparative Examples 4 and 5. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] The first aspect of the present invention provides a layered ternary selenide having a chemical formula of In2Ge2Se6 and a space group of R ， The test results show that the band gap of the layered ternary selenide is 1.43 eV and the thermal conductivity is 2.42 Wm at 300 K. -1 .K -1 , has a narrow band gap and low thermal conductivity, therefore, it can be used in semiconductor optoelectronic devices, solar cells, thermoelectric devices and other fields, and has good application prospects.

[0034] A second aspect of the present invention provides a method for preparing a layered ternary selenide single-phase material, the preparation method comprising the following steps:

[0035] S001. Using indium powder, germanium powder and selenium powder in a molar ratio of 2:2:6 as raw materials, the indium powder, germanium powder and selenium powder are evenly mixed and placed in a quartz tube. Under vacuum conditions, the quartz tube containing the raw materials is sealed using a flame sealing device; the sealed quartz tube is vertically placed in a single-temperature zone pit furnace, the temperature is raised to 950-1000°C, and the temperature is kept at this temperature for 12-24 hours to allow the raw materials in the quartz tube to fully react;

[0036] S002. After the insulation is completed, the temperature is lowered from 950-1000°C to 650-665°C at a cooling rate of 2-5°C / min, and the temperature is kept at 650-665°C for 96-240h. After the insulation is completed, quench and cool to room temperature to obtain a layered ternary In2Ge2Se6 single-phase material.

[0037] The preparation method of the above-mentioned layered ternary selenide single-phase material uses indium powder, germanium powder and selenium powder in a specific ratio as raw materials, and performs high-temperature firing to allow the indium powder, germanium powder and selenium powder to fully react, and performs quenching treatment, especially selecting a heat preservation treatment at 650-665°C and a suitable cooling rate, which can promote the formation of In2Ge2Se6 seed crystals and allow the nucleation to grow, thereby obtaining a layered ternary selenide single-phase material with a larger size.

[0038] In the aforementioned preparation method, since the purity of indium powder, germanium powder and selenium powder will affect the formation of layered ternary selenide single-phase material, in a preferred embodiment, in step S001, the purity of indium powder, germanium powder and selenium powder are all ≥99.99%. By using high-purity raw materials, the influence of impurities in the raw materials on the growth of In2Ge2Se6 seed crystals can be reduced, so that the product will not contain other non-In2Ge2Se6 crystal phases.

[0039] Furthermore, in the aforementioned preparation method, during the firing process, the vacuum degree will also affect the formation of the single-phase material. The higher the vacuum degree, the smaller the influence of air on the crystal, and the smaller the possibility of the formation of impurities in the single-phase body. In this regard, in a preferred embodiment, in the step S001, the vacuum degree is controlled to be ≤1Pa to reduce the influence of air on the high-temperature firing, so as to obtain a layered In2Ge2Se6 single-phase material.

[0040] In addition, in the above-mentioned preparation method, the heating rate in step S001 will also affect the purity of the material. When the heating rate is too fast, the phenomenon of component segregation is likely to occur. In this regard, in a preferred embodiment, in step S001, the heating rate is controlled to be 2-5°C / min, so that each raw material is heated evenly, avoiding the phenomenon of component segregation, and then obtaining a layered In2Ge2Se6 single-phase material.

[0041] The third aspect of the present invention also provides a layered ternary selenium compound single crystal material, the single crystal material is an In2Ge2Se6 thin layer nanosheet, which has c The layered structure in the axial direction of the crystal cThe axial direction is the thickness direction of the In2Ge2Se6 thin layer nanosheet, which can be prepared by mechanical stripping of the layered ternary selenide single-phase material prepared by the aforementioned method, such as by tape pasting or repeated pasting to obtain In2Ge2Se6 thin layer nanosheets or few-layer two-dimensional materials. These In2Ge2Se6 thin layer nanosheets or few-layer two-dimensional materials are single crystal materials, which provide materials for subsequent research on the intrinsic properties of the In2Ge2Se6 selenide and in the fields of semiconductor flexible optoelectronic devices, solar cells and thermoelectric devices.

[0042] In order to further illustrate the preparation methods of the layered ternary selenide and its single-phase material and single-crystalline material provided by the present invention, the following examples and comparative examples are provided.

[0043] Example 1

[0044] This embodiment provides a method for preparing a layered ternary selenide single-phase material, comprising the following steps:

[0045] S001. Using indium powder with a purity of 99.99%, germanium powder with a purity of 99.99%, and selenium powder with a molar ratio of 2:2:6 as raw materials, the indium powder, germanium powder, and selenium powder are evenly mixed and placed in a quartz tube. Under the condition of vacuum degree ≤1Pa, the quartz tube containing the raw materials is sealed using a flame sealing device; then the vacuum-sealed quartz tube is vertically placed in a single-temperature zone pit furnace, the quartz tube is close to the thermocouple, and the temperature is raised from room temperature to 950°C at 5°C / min, and kept at this temperature for 12 hours to allow the raw materials in the quartz tube to fully react;

[0046] S002. After the insulation is completed, the material in the quartz tube is quenched. Specifically, the temperature is cooled from 950°C to 665°C at a cooling rate of 2°C / min and kept at this temperature for 96h; then quenched and cooled to room temperature to obtain a layered ternary In2Ge2Se6 single-phase material;

[0047] S003. Mechanically exfoliate the layered ternary In2Ge2Se6 single-phase material, and repeatedly stick the layered ternary In2Ge2Se6 single-phase material with tape to obtain In2Ge2Se6 thin single crystal nanosheets.

[0048] The morphology, chemical composition and structure of the layered ternary In2Ge2Se6 single-phase material prepared in Example 1 were analyzed and characterized by optical microscope, X-ray diffractometer, scanning electron microscope, X-ray energy spectrometer and transmission electron microscope. The specific characterization results are as follows: Figures 1 to 5As shown. Among them, the A2M2Q6 structural model is given based on theoretical prediction (Journal of Semiconductors, 44 (2023) 042101.), and by analyzing the X-ray energy spectrum ( Figure 4 ) and X-ray powder diffraction patterns ( Figure 2 ), it is determined that the layered ternary In2Ge2Se6 single-phase material obtained in Example 1 is a single-phase material, and its chemical composition is In2Ge2Se6.

[0049] from Figure 3 It can be seen from the scanning electron microscope morphology that the macrostructure of the layered ternary In2Ge2Se6 single-phase material obtained in Example 1 has a layered morphology. The high-angle annular dark field image obtained by transmission electron microscopy further shows that the crystal structure of the obtained layered ternary In2Ge2Se6 material is consistent with the A2M2Q6 structural model (Journal of Semiconductors, 44(2023) 042101.) and has a c Axial layered structure.

[0050] The optical band gap of the layered ternary selenide single-phase material prepared in Example 1 was obtained by testing the UV-Vis absorption spectrum and thermal diffusion coefficient. Figure 6 ) and thermal conductivity ( Figure 7 The material has an optical band gap of 1.43 eV and a thermal conductivity of 2.42 Wm at 300 K. -1 .K -1 .

[0051] In addition, the morphology and structure of the In2Ge2Se6 thin-layer nanosheets obtained in Example 1 were characterized by light microscopy and X-ray diffractometer. Figure 8 and Fig. 9 As shown, from Figure 8 It can be seen that by using the mechanical stripping method of repeated tape pasting, In2Ge2Se6 thin layer nanosheets can be obtained; and by indexing its X-ray powder diffraction spectrum ( Fig. 9 ), it is determined that the crystal plane corresponding to the diffraction peak is the In2Ge2Se6 structure (000 l )( l = 3, 6, 9) crystal planes, indicating that the obtained In2Ge2Se6 thin layer nanosheet is a single crystal material and its sheet thickness direction is the crystallographic direction of the In2Ge2Se6 structure. c Axis orientation.

[0052] Example 2

[0053] This embodiment provides a method for preparing a layered ternary selenide single-phase material, comprising the following steps:

[0054] S001. Using indium powder with a purity of 99.99%, germanium powder with a purity of 99.99%, and selenium powder with a molar ratio of 2:2:6 as raw materials, the indium powder, germanium powder, and selenium powder are uniformly mixed and placed in a quartz tube, and the quartz tube containing the raw materials is sealed using a flame sealing device under the condition of a vacuum degree of ≤1Pa; then the vacuum-sealed quartz tube is vertically placed in a single-temperature zone pit furnace, with the quartz tube close to the thermocouple, and then the temperature is raised from room temperature to 1000°C at 5°C / min, and kept at this temperature for 12 hours to melt the raw materials in the quartz tube;

[0055] S002. After the insulation is completed, the material in the quartz tube is quenched. Specifically, the temperature is reduced from 1000°C to 650°C at a cooling rate of 5°C / min and kept at this temperature for 240 hours; then quenched and cooled to room temperature to obtain a layered ternary In2Ge2Se6 single-phase material.

[0056] The morphology, chemical composition and structure of the obtained material were analyzed and characterized by optical microscope, X-ray diffractometer, scanning electron microscope and X-ray energy spectrometer. Fig.10 As shown by Figure 8 It can be seen that the X-ray powder diffraction spectrum does not show characteristic diffraction peaks of other phases, indicating that the layered ternary In2Ge2Se6 single-phase material prepared in Example 2 is a single-phase material. In addition, it should be noted that since its surface morphology and structure are the same as those in Example 1, the relevant drawings are not displayed.

[0057] Comparative Example 1

[0058] This comparative example provides a method for preparing a selenide, comprising the following steps:

[0059] S001. Using indium powder with a purity of 99.99%, germanium powder with a purity of 99.99%, and selenium powder with a molar ratio of 2:2:6 as raw materials, the indium powder, germanium powder, and selenium powder are uniformly mixed and placed in a quartz tube. Under the condition of vacuum degree ≤1Pa, the quartz tube containing the raw materials is sealed using a flame sealing device; then the vacuum-sealed quartz tube is vertically placed in a single-temperature zone pit furnace, with the quartz tube close to the thermocouple, and then the temperature is raised from room temperature to 950°C at 5°C / min, and kept at this temperature for 12 hours to allow the raw materials in the quartz tube to fully react;

[0060] S002. After the insulation is completed, the material in the quartz tube is directly quenched (water-cooled to room temperature), and then the material is taken out of the quartz tube.

[0061] The physical structure of the material obtained in Comparative Example 1 was analyzed and characterized by an X-ray diffractometer. The characterization results are as follows: Fig. 9 As shown, from Fig.11 It can be seen that the X-ray powder diffraction pattern of the material obtained in Comparative Example 1 shows characteristic diffraction peaks of other phases. The material obtained in Comparative Example 1 includes In2Ge2Se6 phase and a small amount of In2Se3 phase (characteristic diffraction peaks are shown by arrows) and GeSe2 phase (characteristic diffraction peaks are shown by solid circles), and no In2Ge2Se6 single-phase material is obtained.

[0062] Comparative Example 2

[0063] This comparative example provides a method for preparing a selenide, comprising the following steps:

[0064] S001. Using indium powder with a purity of 99.99%, germanium powder with a purity of 99.99%, and selenium powder with a molar ratio of 2:2:6 as raw materials, the indium powder, germanium powder, and selenium powder are uniformly mixed and placed in a quartz tube. Under the condition of vacuum degree ≤1Pa, the quartz tube containing the raw materials is sealed using a flame sealing device; then the vacuum-sealed quartz tube is vertically placed in a single-temperature zone pit furnace, with the quartz tube close to the thermocouple, and then the temperature is raised from room temperature to 950°C at 5°C / min, and kept at this temperature for 12 hours to allow the raw materials in the quartz tube to fully react;

[0065] S002. After the insulation is completed, the material in the quartz tube is quenched. Specifically, the temperature is reduced from 950°C to 680°C at a cooling rate of 2°C / min and maintained at this temperature for 96 hours; then the material is quenched and cooled to room temperature, and then the material is taken out of the quartz tube.

[0066] The physical structure of the material obtained in Comparative Example 2 was analyzed and characterized by an X-ray diffractometer. The characterization results are as follows: Fig.11 As shown, from Fig. 9 It can be seen that the X-ray powder diffraction pattern of the material obtained in Comparative Example 2 shows characteristic diffraction peaks of other phases. The material obtained in Comparative Example 2 includes In2Ge2Se6 phase and In2Se3 phase (characteristic diffraction peaks are shown by arrows), and no In2Ge2Se6 single-phase material is obtained.

[0067] Comparative Example 3

[0068] This comparative example provides a method for preparing a selenide, comprising the following steps:

[0069] S001. Using indium powder with a purity of 99.99%, germanium powder with a purity of 99.99%, and selenium powder with a molar ratio of 2:2:6 as raw materials, the indium powder, germanium powder, and selenium powder are evenly mixed and placed in a quartz tube. Under the condition of vacuum degree ≤1Pa, the quartz tube containing the raw materials is sealed using a flame sealing device; then the vacuum-sealed quartz tube is vertically placed in a single-temperature zone pit furnace, with the quartz tube close to the thermocouple, and then the temperature is raised from room temperature to 950°C at 5°C / min, and kept at this temperature for 24 hours to allow the raw materials in the quartz tube to fully react;

[0070] S002. After the insulation is completed, the material in the quartz tube is quenched. Specifically, the temperature is reduced from 950°C to 640°C at a cooling rate of 2°C / min and maintained at this temperature for 240 hours; then the material is quenched and cooled to room temperature, and then the material is taken out of the quartz tube.

[0071] The physical structure of the material obtained in Comparative Example 3 was analyzed and characterized by X-ray diffractometer. The characterization results are as follows: Fig. 9 As shown, from Fig.11 It can be seen that the X-ray powder diffraction pattern of the material obtained in Comparative Example 3 shows characteristic diffraction peaks of other phases. The material obtained in Comparative Example 3 includes In2Ge2Se6 phase and a small amount of In2Se3 phase (characteristic diffraction peaks are shown by arrows), and no In2Ge2Se6 single-phase material is obtained.

[0072] It can be seen from Comparative Examples 1, 2 and 3 that, during quenching treatment, only by keeping the temperature within a specific range and for a specific time can the In2Ge2Se6 single-phase material be obtained.

[0073] Comparative Example 4

[0074] This comparative example provides a method for preparing a selenide, comprising the following steps:

[0075] S001. Using indium powder with a purity of 99.99%, germanium powder with a purity of 99.99%, and selenium powder with a molar ratio of 2:2.05:6 as raw materials, the indium powder, germanium powder, and selenium powder are evenly mixed and placed in a quartz tube. Under the condition of vacuum degree ≤1Pa, the quartz tube containing the raw materials is sealed using a flame sealing device; then the vacuum-sealed quartz tube is vertically placed in a single-temperature zone pit furnace, with the quartz tube close to the thermocouple, and then the temperature is raised from room temperature to 950℃ at 5℃ / min, and kept at this temperature for 24h to allow the raw materials in the quartz tube to fully react;

[0076] S002. After the insulation is completed, the material in the quartz tube is quenched. Specifically, the temperature is reduced from 950°C to 665°C at a cooling rate of 2°C / min and maintained at this temperature for 96 hours; then the material is quenched and cooled to room temperature, and then the material is taken out of the quartz tube.

[0077] The physical structure of the material obtained in Comparative Example 4 was analyzed and characterized by X-ray diffractometer. The characterization results are as follows: Fig.10 As shown, from Fig.12 It can be seen that the X-ray powder diffraction pattern of the material obtained in Comparative Example 4 shows characteristic diffraction peaks of other phases. The material obtained in Comparative Example 4 includes not only the In2Ge2Se6 phase, but also the In2Se3 phase (the characteristic diffraction peak is shown by the arrow) and other unknown phases (the characteristic diffraction peak is shown by the triangle symbol). No In2Ge2Se6 single-phase material is obtained.

[0078] Comparative Example 5

[0079] This comparative example provides a method for preparing a selenide, comprising the following steps:

[0080] S001. Using indium powder with a purity of 99.99%, germanium powder with a purity of 99.99%, and selenium powder with a molar ratio of 2:1.95:6 as raw materials, the indium powder, germanium powder, and selenium powder are evenly mixed and placed in a quartz tube. Under the condition of vacuum degree ≤1Pa, the quartz tube containing the raw materials is sealed using a flame sealing device; then the vacuum-sealed quartz tube is vertically placed in a single-temperature zone pit furnace, the quartz tube is close to the thermocouple, and the temperature is raised from room temperature to 950°C at 5°C / min, and kept at this temperature for 24 hours to allow the raw materials in the quartz tube to fully react;

[0081] S002. After the insulation is completed, the material in the quartz tube is quenched. Specifically, the temperature is reduced from 950°C to 665°C at a cooling rate of 2.5°C / min and maintained at this temperature for 96 hours; then the material is quenched and cooled to room temperature, and then the material is taken out of the quartz tube.

[0082] The physical structure of the material obtained in Comparative Example 5 was analyzed and characterized by X-ray diffractometer. The characterization results are as follows: Fig.12 As shown, from Fig.12 It can be seen that the X-ray powder diffraction pattern of the material obtained in Comparative Example 5 shows characteristic diffraction peaks of other phases. The material obtained in Comparative Example 5 includes In2Ge2Se6 phase and a small amount of In2Se3 phase (characteristic diffraction peaks are shown by arrows), and no In2Ge2Se6 single-phase material is obtained.

[0083] From Comparative Examples 4 and 5, it can be seen that layered ternary In2Ge2Se6 single-phase material can be obtained only by precisely controlling the dosage ratio of indium powder, germanium powder and selenium powder.

[0084] In summary, the layered ternary selenide single-phase material with the chemical formula In2Ge2Se6 can be prepared by the layered ternary selenide single-phase material preparation method of the present invention. The preparation method expands the material system that can be synthesized by the layered structure A2M2Q6, and provides material support for further physical property research and device development and application of the layered structure A2M2Q6 material system. In the layered ternary In2Ge2Se6 single-phase material prepared by this method, In2Ge2Se6 thin nanosheets or few-layer two-dimensional single crystal materials with an area of ​​millimeters can be obtained by mechanical peeling, which provides materials for the intrinsic property research of such materials in the case of few-layer two-dimensional and their application in the fields of flexible semiconductor optoelectronic devices, solar cells and thermoelectric devices.

[0085] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for preparing a layered ternary selenide single-phase material, characterized in that: The preparation method comprises the following steps: S001. Using indium powder, germanium powder and selenium powder in a molar ratio of 2:2:6 as raw materials, the purity of the indium powder, germanium powder and selenium powder is ≥99.99%, under a vacuum condition of ≤1Pa, heating to 950-1000°C, heating rate of 2-5°C / min, and keeping at this temperature for 12-24h; S002. After the heat preservation is completed, the temperature is lowered to 650-665°C at a cooling rate of 2-5°C / min, and the temperature is kept at 650-665°C for 96-240h; after the heat preservation is completed, the material is quenched and cooled to room temperature to obtain a layered ternary selenide single-phase material with a chemical formula of In2Ge2Se6, and its space group is R .

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