Preparation method of nano thermoelectric material

Abstract

The invention relates to the technical field of electric materials, in particular to a preparation method of a nano thermoelectric material, which enhances local surface plasma resonance of a copper chalcogenide nano thermoelectric material through laser induction at normal temperature, and has the characteristics of simple process and high process efficiency. The material synthesized by the method not only has the original advantages of being used as a thermoelectric material, but also combines the LSPR characteristics. The problems that in the prior art, a nano thermoelectric material is low in optical performance, difficult to meet the application requirement of light-operated micro-nano particles, difficult to prepare, tedious in preparation process and the like are solved.

Description

[Technical field]

[0001] The invention belongs to the technical field of electric materials, and in particular relates to a method for preparing a nano thermoelectric material. [Background technology]

[0002] Localized surface plasmon resonance (LSPR) is a collective free-carrier oscillation behavior originally discovered in noble metals, which has led to hot fields such as plasmonics. It is often used in metal nanomaterials and inorganic non-metallic materials.

[0003] Copper chalcogenides have attracted increasing attention as promising thermoelectric materials due to their high efficiency, tunable transport properties, high element abundance and low toxicity. Thermoelectric materials can achieve direct conversion of thermal energy and electrical energy, and have attracted widespread attention in the context of the increasingly severe environmental and energy crisis. The performance of thermoelectric materials is usually evaluated by the dimensionless performance coefficient (zT), which is defined as zT = S2σT / κ, where S is the Seebeck coefficient, σ is the electrical conductivity, κ is the thermal conductivity, and T is the absolute temperature. There is a strong correlation between these transport parameters, and improving electrical conductivity and reducing thermal conductivity are the keys to obtaining a better zT.

[0004] Currently these technologies have the following problems:

[0005] (1) Currently, thermoelectric materials are only focused on improving thermoelectric performance, and the carrier concentration requirement range of the best thermoelectric materials just coincides with the carrier concentration range required by the near-infrared LSPR. However, under the premise of further ensuring the thermoelectric performance of semiconductor materials, there are still technical difficulties in how to improve the light absorption of materials in the near-infrared region and link the LSPR optical performance with the thermoelectric performance.

[0006] (2) Copper chalcogenide nanomaterials can regulate the LSPR characteristics by changing the size and shape, or by doping, temperature and phase change. However, the steps required are cumbersome and the process is difficult. In addition, the corresponding improvement of LSPR performance often damages its thermoelectric performance. Currently, copper chalcogenide nanomaterials lack a way to stably regulate the LSPR characteristics while ensuring thermoelectric performance.

[0007] (3) Currently, most studies focus on the preparation of bulk thermoelectric materials by high-temperature (>1000K) solid-phase reactions. There is an urgent need for a good method to synthesize and control nano-thermoelectric materials at room temperature.

[0008] (4) Currently, the application of nano-thermoelectric materials has attracted widespread attention. However, there are still technical difficulties in the development and research of related materials to regulate their thermoelectric effect through optical means. It is necessary to integrate the photothermal effect and thermoelectric effect to develop light-controlled nano-thermoelectric materials.

[0009] Based on this, the present application proposes a method for laser-induced enhancement of local surface plasmon resonance of copper-chalcogenide nano-thermoelectric materials to solve the above problems. [Summary of the invention]

[0010] In view of the above, it is necessary to provide a method for preparing nano thermoelectric materials, which can synthesize nano thermoelectric materials at room temperature and has the characteristics of simple process and high process efficiency.

[0011] In order to achieve the above object, the technical solution adopted by the present invention is:

[0012] A method for preparing a nano thermoelectric material, the method comprising the following steps:

[0013] (1) Synthesis of CuAgSe: CuAgSe was synthesized in a round-bottom flask, stirred for 1-3 hours, dialyzed through a dialysis membrane to remove small molecules, and then centrifuged to remove large molecules. The synthesized CuAgSe was then stored at low temperature for future use;

[0014] (2) preparing a solution: taking out the synthesized CuAgSe and dissolving it in water to form a solution;

[0015] (3) Laser smelting: Take the solution obtained in step (2), place it in a centrifuge tube, and irradiate the solution in the centrifuge tube with a high-power continuous laser. When the temperature reaches above 60° C., turn off the laser, remove the centrifuge tube and cool it, and the nano thermoelectric material can be obtained.

[0016] In the present invention, further, in step (1), the molecular weight cutoff of the dialysis membrane is 10 kDa, and the purification time is 24 h.

[0017] In the present invention, further, the step (1) storing at low temperature is specifically storing in a refrigerator at 4°C.

[0018] In the present invention, further, the wavelength of the continuous laser in step (3) is 532nm to 1064nm.

[0019] The present invention also provides an application of nano thermoelectric materials in the field of life science treatment, overcoming the limitations of traditional photothermal therapy and thermoelectric therapy.

[0020] The present invention has the following beneficial effects:

[0021] 1. The present invention proposes a novel method for preparing nano thermoelectric materials. By laser-induced regulation of the LSPR characteristics of copper chalcogenide thermoelectric materials, good photothermal effect and efficient thermoelectric effect of copper chalcogenide nano thermoelectric materials in the near-infrared region II are achieved, thus breaking through the bottleneck of weak optical properties of copper chalcogenide nano thermoelectric materials and proposing a new solution to solve the problem of weak optical properties of thermoelectric materials.

[0022] 2. Most existing studies focus on the preparation of bulk thermoelectric materials by high-temperature solid-phase reaction, while the method of the present invention can change the local surface plasmon resonance characteristics of copper-sulfur nano-thermoelectric materials at room temperature. This method regulates the LSPR performance of copper-sulfur nano-thermoelectric materials. The laser-induced material has both high ZT value and high light absorption, combining the advantages of thermoelectricity and LSPR, and becomes a good photothermoelectric material. It is used in the field of life science treatment to overcome the limitations of traditional photothermal therapy and thermoelectric therapy and improve the effect of single treatment.

Brief Description of the Drawings

[0023] Figure 1 This is the temperature change spectrum of CuAgSe after laser irradiation;

[0024] Figure 2 The UV spectrum of CuAgSe before and after laser treatment;

[0025] Figure 3 This is the crystal structure change of XRD before and after laser. [Specific implementation method]

[0026] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific implementation disclosed below.

[0027] Embodiment 1:

[0028] This embodiment provides a method for preparing a nano thermoelectric material, the method comprising the following steps:

[0029] (1) Synthesis of CuAgSe: CuAgSe was synthesized in a round-bottom flask and stirred for 1-3 h. It was dialyzed through a 10 kDa dialysis membrane to remove small molecules, and then centrifuged to remove large molecules. The synthesized CuAgSe was then stored in a refrigerator at 4°C for future use.

[0030] (2) preparing a solution: taking out the synthesized CuAgSe and dissolving it in water to form a solution;

[0031] (3) Laser smelting: Take the solution obtained in step (2), place it in a centrifuge tube, and irradiate the solution in the centrifuge tube with a high-power continuous laser (wavelength of 532nm-2800nm). When the temperature reaches above 60°C (due to changes in local surface plasma resonance, a sudden change in temperature will be observed), turn off the laser, remove the centrifuge tube for cooling, and the nano thermoelectric material can be obtained. Analysis shows that when a strong laser interacts with the surface of a non-metallic nano thermoelectric material, the laser energy stored in the semiconductor material due to carrier absorption will heat the hot carriers in the thermoelectric material to a higher temperature within tens of seconds, and through the rapid collision of electrons and electrons, electrons and holes, lattice defects will appear.

[0032] Embodiment 2:

[0033] This embodiment uses an ultraviolet spectrophotometer to test the spectrum of the material after laser irradiation from ultraviolet to near infrared:

[0034] The ultraviolet-near infrared spectrum of CuAgSe before and after laser irradiation was tested by ultraviolet spectrophotometer. The results are as follows: Figure 1 As shown, obvious changes in the position and intensity of the absorption peak were observed, proving that continuous laser irradiation changes the local surface plasmon resonance of CuAgSe.

[0035] Embodiment 3:

[0036] This example uses an X-ray diffractometer to further test the copper-based non-metallic nano-thermoelectric material before and after laser treatment:

[0037] X-ray diffractometer was used to further test CuAgSe before and after laser treatment for comparison. The results are as follows: Figure 3 As shown, it was found that the CuAgSe crystal structure did not change before and after the laser, but the diffraction peak intensity changed, proving that continuous laser irradiation destroyed the CuAgSe atomic structure and created more atomic vacancies and defects.

[0038] Embodiment 4:

[0039] This example tests the carrier concentration of the nano thermoelectric material before and after the laser:

[0040] The carrier concentration of CuAgSe before and after the laser was tested and compared. The results are shown in Table 1:

[0041] Table 1 Changes in material impedance and carrier density before and after laser

[0042] Material CuAgSe before laser CuAgSe after laser impedance 87.5 67.1 <![CDATA[Carrier density (cm -3 )]]> <![CDATA[7.17×10 19 ]]> <![CDATA[5.15×10 20 ]]>

[0043] Observing the results in Table 1, it is found that the carrier concentration is significantly increased after laser irradiation, which proves that continuous laser irradiation changes the local surface plasmon resonance characteristics of CuAgSe by changing the hot carrier concentration.

[0044] Embodiment 5:

[0045] In this example, the performance of the obtained nano thermoelectric material was tested, and the photothermal effect showed changes such as Figure 2 shown.

[0046] The above-mentioned embodiments merely express several implementation modes of the present invention, and the description thereof is relatively specific and detailed, but it should not be understood as limiting the scope of the present invention.

Claims

1. A method for preparing a nano thermoelectric material, characterized in that: The method comprises the following steps: (1) Synthesis of CuAgSe: CuAgSe was synthesized in a round-bottom flask, stirred for 1-3 hours, dialyzed through a dialysis membrane to remove small molecules, and then centrifuged to remove large molecules. The synthesized CuAgSe was then stored at low temperature for future use; (2) preparing a solution: taking out the synthesized CuAgSe and dissolving it in water to form a solution; (3) Laser smelting: Take the solution obtained in step (2), place it in a centrifuge tube, and irradiate the solution in the centrifuge tube with a high-power continuous laser. When the temperature reaches above 60° C., turn off the laser, remove the centrifuge tube and cool it, and the nano thermoelectric material can be obtained.

2. The method according to claim 1, characterized in that In the step (1), the molecular weight cutoff of the dialysis membrane is 10 kDa, and the purification time is 24 h.

3. The method according to claim 1, characterized in that: The step (1) of storing at low temperature specifically means storing in a refrigerator at 4°C.

4. The method according to claim 1, characterized in that: The wavelength of the continuous laser in step (3) is 532nm to 2800nm.

5. Application of the nano thermoelectric material according to any one of claims 1 to 4 in the field of life science treatment.

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