阅读说明：本技术 三元原子晶体剥离制备二维层状材料的方法 (Method for preparing two-dimensional layered material by stripping ternary atomic crystal ) 是由 封伟 张鑫 王宇 赵付来 冯奕钰 李瑀 于 2018-07-10 设计创作，主要内容包括：本发明公开三元原子晶体剥离制备二维层状材料的方法,以GaGeLi晶体为前驱体,分散于乙醇中,用氩气脱气后以Teflon胶带密封,超声处理并避免浴缸和液体过热,水冷维持在20—25℃,再离心分离即可得到二维层状半导体材料2D-GaGeLi。其光学带隙与剥离所得层数有关,层数越少,带隙越大。在光电器件、光催化等方面应用有具有较大的潜在性。(The invention discloses a method for preparing a two-dimensional layered material by stripping a ternary atomic crystal, which comprises the steps of taking a GaGeLi crystal as a precursor, dispersing the GaGeLi crystal in ethanol, degassing by argon, sealing by a Teflon adhesive tape, carrying out ultrasonic treatment, avoiding overheating of a bathtub and liquid, carrying out water cooling at 20-25 ℃, and carrying out centrifugal separation to obtain the two-dimensional layered semiconductor material 2D-GaGeLi. The optical band gap is related to the number of layers obtained by the exfoliation, and the smaller the number of layers, the larger the band gap. The method has great potential in the aspects of photoelectric devices, photocatalysis and the like.)

1. The method for preparing the two-dimensional layered material by stripping the ternary atomic crystal is characterized by comprising the following steps of: vacuum packaging and processing three metals of Ga, Ge and Li according to an equal molar ratio to obtain a GaGeLi crystal, raising the temperature to 1000-1100 ℃ within 350-450 min from 20-25 ℃, maintaining the temperature for 1000-1200 min, and then reducing the temperature to 20-25 ℃ at the speed of 0.5-3 ℃/min; dispersing the GaGeLi crystals in ethanol, degassing by using an inert protective atmosphere, sealing, continuously performing ultrasonic treatment, simultaneously maintaining the temperature at 20-25 ℃ by adopting water cooling to avoid overheating in the ultrasonic treatment process, and finally performing centrifugal separation to obtain the two-dimensional layered semiconductor material 2D-GaGeLi.

2. The method for preparing the two-dimensional layered material by stripping the ternary atomic crystal as in claim 1, wherein the vacuum degree is below 0.1MPa when the three metals of Ga, Ge and Li are subjected to vacuum packaging and treatment.

3. The method for preparing two-dimensional layered material by stripping ternary atomic crystal as claimed in claim 1, wherein the temperature is raised to 1000-1050 ℃ from 20-25 ℃ within 380-400 min, maintained for 1100-1200 min, and then lowered to 20-25 ℃ at 0.5-1 ℃/min.

4. The method for preparing two-dimensional layered material by peeling ternary atomic crystal according to claim 1, wherein the inert protective atmosphere is nitrogen, helium or argon.

5. The method for preparing a two-dimensional layered material by ternary atomic crystal exfoliation according to claim 1, characterized in that degassing is performed using an inert protective atmosphere and then sealing with Teflon tape.

6. The method for preparing a two-dimensional layered material by peeling the ternary atomic crystal as claimed in claim 1, wherein the centrifugation rate is 3000 to 5000 rmp.

7. The method for preparing a two-dimensional layered material by exfoliation of a ternary atomic crystal as claimed in claim 1, wherein the ultrasonication time is 5-20 hours, preferably 10-15 hours.

8. The method for preparing a two-dimensional layered material by ternary atomic crystal exfoliation according to claim 1, wherein the GaGeLi crystals are dispersed in ethanol in a ratio of the mass (mg) of the GaGeLi crystals to the volume (ml) of ethanol of (1 to 5): 1, preferably (2-4): 1.

Technical Field

The invention belongs to the preparation of novel two-dimensional materials, and particularly relates to a simple preparation method for obtaining a two-dimensional material from a ternary crystal.

Background

Two-dimensional layered metal material, especiallyIt is a chalcogenide compound (2DLMCs) that brings about an electronic structure and optical properties different from those of bulk materials based on its ultra-thin structure, and has a special phenomenon such as quantum effect, energy valley effect, and the like. After the graphene is found, the two-dimensional material is rapidly explored and researched, wherein the two-dimensional layered transition metal sulfur compound (TMDCs: MoS) with the similar graphene structure and the adjustable band gap₂、WS₂Etc.), group iii-iv compounds (GeS, InSe, etc.) and their associated heterojunctions have become one of the research focuses in recent years. Compared with binary metal crystals, the preparation of ternary crystals is relatively more difficult, and the problems of difficult uniform eutectic melting, difficult determination of eutectic point and the like are solved, and the ternary crystals are unstable in air and easy to oxidize, so that related reports are few. In 2008, UlrichHausssermann et al prepared a ternary metal precursor by arc remelting and stabilized it by hydrogenation on the basis of the work of the predecessors, to obtain a quaternary crystal AeGaEH (Ae: Ca, Sr, Ba; E: Si, Ge, Sn), in which BaGaSiH, the bulk material, had a band gap of 0.6 eV.

Disclosure of Invention

The invention aims to overcome the defects of the prior art, provides a method for preparing a two-dimensional layered material by stripping a ternary atomic crystal, and starts with a ternary crystal precursor to further simply prepare a novel two-dimensional material.

The technical purpose of the invention is realized by the following technical scheme:

the method for preparing the two-dimensional layered material by stripping the ternary atomic crystal comprises the following steps: vacuum packaging and processing three metals of Ga, Ge and Li according to an equal molar ratio to obtain a GaGeLi crystal, raising the temperature to 1000-1100 ℃ within 350-450 min from 20-25 ℃, maintaining the temperature for 1000-1200 min, and then reducing the temperature to 20-25 ℃ at the speed of 0.5-3 ℃/min; dispersing the GaGeLi crystals in ethanol, degassing by using an inert protective atmosphere, sealing, continuously performing ultrasonic treatment, simultaneously maintaining the temperature at 20-25 ℃ by using water cooling to avoid overheating (such as bathtub and liquid overheating) in the ultrasonic treatment process, and finally performing centrifugal separation to obtain the two-dimensional layered semiconductor material 2D-GaGeLi.

In the technical scheme, when the three metals of Ga, Ge and Li are subjected to vacuum packaging and processing, the vacuum degree is below 0.1 MPa.

In the technical scheme, the temperature is increased to 1000-1050 ℃ within 380-400 min from 20-25 ℃, is maintained for 1100-1200 min, and is reduced to 20-25 ℃ at the speed of 0.5-1 ℃/min.

In the technical scheme, the inert protective atmosphere is nitrogen, helium or argon.

In the above technical scheme, degassing is performed by using an inert protective atmosphere, and then sealing is performed by using a Teflon tape.

In the technical scheme, the centrifugal rate is 3000-5000 rmp during centrifugal separation.

In the above technical scheme, the ultrasonic treatment time is 5 to 20 hours, preferably 10 to 15 hours.

In the above technical scheme, the GaGeLi crystals are dispersed in ethanol, and the ratio of the mass (mg) of the GaGeLi crystals to the volume (ml) of the ethanol is (1-5): 1, preferably (2-4): 1.

compared with a binary precursor material for preparing a two-dimensional material, in the technical scheme of the invention, the GaGeLi is used as the precursor, the precursor is directly dispersed in an ethanol solvent, and centrifugal treatment (stripping) is carried out after ultrasonic treatment to obtain the ternary crystal two-dimensional material (namely, the ternary precursor is prepared firstly, and the two-dimensional material is prepared by a solution method). Ternary crystals are selected in the preparation process, and the obtained novel two-dimensional material has good electrical property and optical property.

Drawings

FIG. 1 is a scanning electron microscope image of a GaGeLi bulk material obtained by the technical scheme of the invention.

Fig. 2 is an XRD pattern of the GaGeLi crystal obtained according to the technical scheme of the present invention.

FIG. 3 is a diagram of UV-VIS absorption spectra for different numbers of layers obtained by the present invention.

Detailed Description

The present invention will be further described with reference to the following embodiments. The following examples of the present invention are given to further illustrate the present invention, but not to limit the scope of the present invention.

Example 1

Weighing 10mmol Ga, 10mmol Ge and 10mmol Li (powder) in a glove box in sequence, adding the powder into a quartz tube in sequence, sealing by using a vacuum sealing device, sintering in a vacuum tube furnace, raising the temperature from normal temperature (20-25 ℃) to 1000 ℃ within 400min, maintaining the temperature for 1200min, and then cooling to the normal temperature (20-25 ℃) at the speed of 0.5 ℃/min. And (3) dispersing 60mg of the precursor (namely the treated ternary GaGeLi) into a 20ml transparent glass bottle filled with 15ml of water, degassing by argon, sealing by a Teflon adhesive tape, carrying out ultrasonic treatment for 12h while avoiding overheating of a bathtub and liquid, and centrifuging for 20min in a desktop centrifuge of 3000rmp at room temperature by adopting water cooling to maintain the temperature at 20 ℃ to obtain the 2D-GaGeLi layered material.

Example 2

Weighing 10mmol Ga, 10mmol Ge and 10mmol Li in a glove box in sequence, adding into a quartz tube in sequence, sealing by using a vacuum sealing device, sintering in a vacuum tube furnace, raising the temperature from normal temperature to 1000 ℃ in 400min, maintaining for 1200min, and then cooling to normal temperature at 0.5 ℃/min. And (3) dispersing 60mg of the precursor into a 20ml transparent glass bottle filled with 15ml of water, degassing by argon, sealing by a Teflon adhesive tape, carrying out ultrasonic treatment for 12h to avoid overheating of a bathtub and liquid, and centrifuging for 20min in a 4000rmp bench centrifuge at room temperature by water cooling at 20 ℃ to obtain the 2D-GaGeLi layered material.

Example 3

Weighing 10mmol Ga, 10mmol Ge and 10mmol Li in a glove box in sequence, adding into a quartz tube in sequence, sealing by using a vacuum sealing device, sintering in a vacuum tube furnace, raising the temperature from normal temperature to 1000 ℃ in 400min, maintaining for 1200min, and then cooling to normal temperature at 0.5 ℃/min. And (3) dispersing 60mg of the precursor into a 20ml transparent glass bottle filled with 15ml of water, degassing by argon, sealing by a Teflon adhesive tape, carrying out ultrasonic treatment for 12h to avoid overheating of a bathtub and liquid, and centrifuging for 20min in a 5000rmp desktop centrifuge at room temperature by water cooling at 20 ℃ to obtain the 2D-GaGeLi layered material.

Example 4

Weighing 10mmol Ga, 10mmol Ge and 10mmol Li in a glove box in sequence, adding into a quartz tube in sequence, sealing by using a vacuum sealing device, sintering in a vacuum tube furnace, raising the temperature from normal temperature to 1000 ℃ in 400min, maintaining for 1200min, and then cooling to normal temperature at 0.5 ℃/min. And (3) dispersing 60mg of the precursor into a 20ml transparent glass bottle filled with 15ml of NMP, degassing by argon, sealing by a Teflon adhesive tape, carrying out ultrasonic treatment for 12h to avoid overheating of a bathtub and liquid, carrying out water cooling, maintaining the temperature at 20 ℃, and centrifuging for 20min in a desktop centrifuge of 3000rmp at room temperature to obtain the 2D-GaGeLi layered material.

Example 5

Weighing 10mmol Ga, 10mmol Ge and 10mmol Li in a glove box in sequence, adding into a quartz tube in sequence, sealing by using a vacuum sealing device, sintering in a vacuum tube furnace, raising the temperature from normal temperature to 1000 ℃ in 400min, maintaining for 1200min, and then cooling to normal temperature at 0.5 ℃/min. And (3) dispersing 60mg of the precursor into a 20ml transparent glass bottle filled with 15ml of DMF, degassing by argon, sealing by a Teflon adhesive tape, carrying out ultrasonic treatment for 12h to avoid overheating of a bathtub and liquid, and centrifuging for 20min in a desktop centrifuge of 3000rmp at room temperature by water cooling at 20 ℃ to obtain the 2D-GaGeLi layered material.

Example 6

Weighing 10mmol Ga, 10mmol Ge and 10mmol Li in a glove box in sequence, adding into a quartz tube in sequence, sealing by using a vacuum sealing device, sintering in a vacuum tube furnace, raising the temperature from normal temperature to 1000 ℃ in 400min, maintaining for 1200min, and then cooling to normal temperature at 0.5 ℃/min. And (3) dispersing 60mg of the precursor into a 20ml transparent glass bottle filled with 15ml of ethanol, degassing by argon, sealing by a Teflon adhesive tape, carrying out ultrasonic treatment for 12h to avoid overheating of a bathtub and liquid, and centrifuging for 20min in a desktop centrifuge of 3000rmp at room temperature by water cooling at 20 ℃ to obtain the 2D-GaGeLi layered material.

Taking the example of the material preparation in example 6 as an example, as shown in the attached figures 1 to 3, the 2D-GaGeLi layered material successfully prepared by the technical scheme of the present invention is subjected to optical band gap measurement on different numbers of layers in an ultraviolet-visible absorption spectrum, GaGeLi without any treatment (i.e., ultrasonic centrifugal peeling) almost has no band gap, and the band gap gradually increases as the number of layers gradually decreases, and the centrifugal rate is increased to obtain a single layer of GaGeLi with a band gap of 0.48 eV.

The preparation of the two-dimensional material can be realized by adopting the process parameters of the invention, and the basically consistent performance is shown. The invention has been described in an illustrative manner, and it is to be understood that any simple variations, modifications or other equivalent changes which can be made by one skilled in the art without departing from the spirit of the invention fall within the scope of the invention.