CN111799361B - Liquid crystal carbon nano tube composite thermoelectric material and preparation method thereof - Google Patents
Liquid crystal carbon nano tube composite thermoelectric material and preparation method thereof Download PDFInfo
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- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N10/00—Thermoelectric devices comprising a junction of dissimilar materials, i.e. devices exhibiting Seebeck or Peltier effects
- H10N10/80—Constructional details
- H10N10/85—Thermoelectric active materials
- H10N10/856—Thermoelectric active materials comprising organic compositions
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y40/00—Manufacture or treatment of nanostructures
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- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N10/00—Thermoelectric devices comprising a junction of dissimilar materials, i.e. devices exhibiting Seebeck or Peltier effects
- H10N10/01—Manufacture or treatment
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- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N10/00—Thermoelectric devices comprising a junction of dissimilar materials, i.e. devices exhibiting Seebeck or Peltier effects
- H10N10/80—Constructional details
- H10N10/85—Thermoelectric active materials
- H10N10/851—Thermoelectric active materials comprising inorganic compositions
- H10N10/855—Thermoelectric active materials comprising inorganic compositions comprising compounds containing boron, carbon, oxygen or nitrogen
Abstract
The invention discloses a liquid crystal carbon nano tube composite thermoelectric material and a preparation method thereof, wherein the composite thermoelectric material comprises the following components: the liquid crystal display comprises discotic liquid crystal molecules and single-arm carbon nanotubes, wherein the discotic liquid crystal molecules are attached to the single-arm carbon nanotubes; the discotic liquid crystal molecules consist of discotic cores and a plurality of side chains connected with the peripheries of the discotic cores, and the structural general formula of the discotic liquid crystal molecules is shown as follows:wherein the disc-shaped nucleus is polycyclic aromatic hydrocarbon, and the side chain is an alkyl side chain. The composite thermoelectric material provided by the invention has high Seebeck coefficient, conductivity and power factor, good flexibility and certain mechanical property, so that the novel liquid crystal/carbon nano tube composite thermoelectric material is expected to be applied to flexible wearable thermoelectric equipment. Compared with the traditional inorganic thermoelectric material, the preparation method is simple and easy to realize, low in cost and easy to process and form.
Description
Technical Field
The invention relates to the technical field of thermoelectric materials, in particular to a composite thermoelectric material and a preparation method thereof.
Background
Currently, about two thirds of energy is dissipated in the form of waste heat during actual use of fossil fuel as a main energy source, and the utilization efficiency of the energy source can be improved by the secondary utilization of the waste heat. The thermoelectric device can realize direct conversion of heat energy and electric energy, has the advantages of less pollution, no noise, no mechanical loss and the like, and is an ideal environment-friendly energy conversion device. Thermoelectric materials are semiconductor functional materials that utilize the movement of solid internal carriers to achieve the interconversion between thermal and electrical energy, and mainly include three basic physical phenomena: the Seebeck effect (temperature difference creates an electric field), the Peltier effect (electric field drives carriers to wick/release heat through the heterojunction interface), and the Thomson effect (describing the heating and cooling process of a current carrying conductor with a temperature gradient). These three effects constitute a complete system describing the direct conversion of thermoelectric energy to physical effects. The energy source material has the advantages of small volume, light weight, quiet running, no need of converting medium and mechanical movable parts and the like, and is widely paid attention to as a novel energy source material.
The performance of the thermoelectric material is determined by the dimensionless thermoelectric figure of merit zt=s 2 Sigma T/kappa, where S is the Seebeck coefficient of the material, sigma is the electrical conductivity, T is the absolute temperature of thermodynamics, and kappa is the thermal conductivity. The larger the ZT value, the higher the thermoelectric conversion efficiency, and the more excellent the performance of the thermoelectric material, so that an excellent thermoelectric material must have a high Seebeck coefficient and a high electrical conductivity (S is generally 2 σ is called a Power Factor (PF)), and low thermal conductivity. The three important parameters S, sigma and k for determining the thermoelectric performance of the material are closely related, and the pursuing of the increase or decrease of one parameter alone often leads to the non-synergistic change of the other parameter, which is the root cause of the difficulty in continuously improving the thermoelectric performance ZT. Therefore, realizing independent or cooperative regulation and control of electric and thermal transport is a long-sought goal in the field of thermoelectric material science.
Thermoelectric materials are largely classified into inorganic thermoelectric materials and organic thermoelectric materials. In recent years, inorganic thermoelectric materials have been rapidly developed, such as PbTe, geTe, bi 2 Te 3 Sb 2 Te 3 And the like, a certain research result is obtained. However, these materials have the problems of extremely high manufacturing cost, less resources and difficult processingThe disadvantages of toxicity, etc., thus greatly limiting the large-scale commercial application of the catalyst in thermoelectric energy conversion. Compared with inorganic thermoelectric materials, the organic thermoelectric materials have the outstanding advantages of abundant resources, low price, easy synthesis, easy processing, low heat conductivity and the like, and have good development potential in the field of thermoelectric materials. In addition, the thermoelectric device made of the organic thermoelectric material has the advantages of portability, flexibility, no toxicity, wearable performance and the like, and has great potential in applications such as power generation in remote areas (such as military field deployment) and power supply of small mobile wireless devices requiring low power consumption (such as health sensors of athletes or emergency response personnel). However, the thermoelectric performance of the eigenstate is too poor, which severely limits the further development of organic thermoelectric materials. The single-arm carbon nanotube (SWCNT) has larger specific surface area and conjugated pi-pi structure, excellent electrical conductivity and good mechanical property, and is mixed with an organic thermoelectric material (polymer or small molecule) to form a composite material, so that the composite material has the double advantages of low thermal conductivity of an organic phase and high electrical conductivity of an inorganic phase, and is a novel thermoelectric material which has more researches and has faster development in recent years. However, the thermoelectric performance is further improved compared to the conventional inorganic thermoelectric material.
Thus, the development of new organic materials in composite materials is one of the most straightforward and effective ways to address their lower thermoelectric performance.
Disclosure of Invention
In view of the above-mentioned shortcomings of the prior art, the present invention aims to provide a composite thermoelectric material and a preparation method thereof, which aims to solve the problem of low thermoelectric performance of the existing composite thermoelectric material based on carbon nanotubes.
The technical scheme of the invention is as follows:
a composite thermoelectric material, wherein the composite thermoelectric material comprises: the liquid crystal display comprises discotic liquid crystal molecules and single-arm carbon nanotubes, wherein the discotic liquid crystal molecules are attached to the single-arm carbon nanotubes;
the discotic liquid crystal molecules consist of discotic cores and a plurality of side chains connected with the peripheries of the discotic cores, and the structural general formula of the discotic liquid crystal molecules is shown as follows:
wherein the disc-shaped nucleus is polycyclic aromatic hydrocarbon, and the side chain is an alkyl side chain.
Optionally, the polycyclic aromatic hydrocarbon is selected from one of the following structural formulas:
alternatively, the alkyl side chain has the general molecular formula-C n H 2n+1 Wherein n has a value of 6-20;
the alkyl side chain is directly connected with the disc-shaped core; alternatively, the alkyl side chain is linked to the discotic core with an ether linkage, thioether linkage, ester linkage, amide linkage.
Optionally, in the composite thermoelectric material, the mass ratio of the discotic liquid crystal molecules to the single-arm carbon nanotubes is (1-9): 10.
the preparation method of the composite thermoelectric material comprises the following steps:
dispersing the single-arm carbon nano tube in an organic solvent, and uniformly stirring to obtain a single-arm carbon nano tube solution;
adding discotic liquid crystal molecules into the single-arm carbon nanotube solution, and uniformly stirring to obtain a mixed solution;
and (3) taking the mixed solution on a substrate, and naturally airing to obtain the composite thermoelectric material.
Optionally, the organic solvent is one or more of chlorobenzene, dichlorobenzene, toluene, tetrahydrofuran and chloroform.
Optionally, in the step of dispersing the single-arm carbon nanotubes in the organic solvent and uniformly stirring, the stirring is ultrasonic stirring, and the time of ultrasonic stirring is 3-12 hours.
Optionally, in the mixed solution, the mass of the discotic liquid crystal molecules is 10-90% of the mass of the single-arm carbon nanotubes.
Optionally, the step of taking the mixed solution on the substrate includes: taking 100-500 mu L of the mixed solution with the area of 1 multiplied by 1cm 2 Or 1.5X1.5 cm 2 Is provided.
Optionally, the substrate is a glass substrate.
The beneficial effects are that: the invention provides a novel composite thermoelectric material based on the composition of discotic liquid crystal molecules and single-arm carbon nanotubes. Besides higher power factor, the composite thermoelectric material has good flexibility and certain mechanical properties, so that the organic thermoelectric film material is expected to be applied to flexible wearable thermoelectric equipment. Compared with the traditional inorganic thermoelectric material, the preparation method of the composite thermoelectric material is simple, easy to realize, low in cost and easy to process and form.
Drawings
FIG. 1 is a schematic diagram showing the structure of a discotic liquid crystal molecule HAT6 according to an embodiment of the present invention;
FIG. 2 is a POM (polarizing microscope) diagram of a discotic liquid crystal molecule HAT6 according to an embodiment of the present invention;
FIG. 3 is a DSC (differential thermal analyzer) diagram of a discotic liquid crystal molecule HAT6 in an embodiment of the present invention;
FIG. 4 is a graph showing the Raman spectra of films made of different recombination ratios (SWCNT/HAT6=1:0.25, 1:0.5,1:1, 1:4) and pure carbon nanotube films of a composite thermoelectric material composited with single-arm carbon nanotubes according to an embodiment of the present invention;
FIG. 5 is an XRD (X-ray diffraction) chart of films made of different recombination ratios (SWCNT/HAT6=1:0.25, 1:0.5,1:1, 1:4) and pure carbon nanotube films of composite thermoelectric materials composited with single-arm carbon nanotubes in an embodiment of the present invention;
FIGS. 6 a-6 d are SEM (scanning electron microscope) images of the surfaces of films made of composite thermoelectric materials having a single-arm carbon nanotube to discotic liquid crystal molecule composite ratio of 1:0.25,1:0.5,1:1,1:4, respectively, in specific embodiments of the present invention;
FIG. 7 is a graph showing Seebeck coefficients of films made of composite thermoelectric materials with different composite ratios (SWCNT/HAT6=1:0.25, 1:0.5,1:1, 1:4) and pure carbon nanotube films at room temperature (300 k) for a composite thermoelectric material with a single-arm carbon nanotube composite in an embodiment of the present invention;
FIG. 8 is a graph showing the conductivity of films made of different recombination ratios (SWCNT/HAT6=1:0.25, 1:0.5,1:1, 1:4) and pure carbon nanotube films at room temperature (300 k) of a composite thermoelectric material composited with single-arm carbon nanotubes in an embodiment of the present invention;
fig. 9 is a graph showing power factor at room temperature (300 k) for films made of different recombination ratios (SWCNT/HAT 6=1:0.25, 1:0.5,1:1, 1:4) and pure carbon nanotube films of composite thermoelectric materials composited with single-arm carbon nanotubes in an embodiment of the present invention.
Detailed Description
The invention provides a composite thermoelectric material and a preparation method thereof, and the invention is further described in detail below in order to make the purposes, technical schemes and effects of the invention clearer and more definite. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.
In particular, thermoelectric materials having excellent properties need to have a large Seebeck coefficient and high electrical conductivity as well as low thermal conductivity, whereas organic thermoelectric materials have low electrical conductivity due to the high thermal conductivity of existing inorganic thermoelectric materials, resulting in poor thermoelectric properties of their pure inorganic or organic thermoelectric materials. The organic/inorganic composite thermoelectric material can combine the dual advantages of high conductivity of inorganic materials, high Seebeck coefficient and low thermal conductivity of organic materials to obtain excellent thermoelectric performance.
The inventors have found that discotic liquid crystal molecules are generally composed of a planar rigid aromatic core with peripheral alkyl side chains. The strong pi-pi interaction between the aromatic central cores is self-assembled and stacked into a column shape, so that a rapid channel is provided for the transmission of carriers. The peripheral alkyl side chains can increase the molecular solubility and provide an external insulating environment for the carrier transport channels. The discotic liquid crystal molecules have strong self-assembly performance, stable structure and order, excellent photoelectric performance and remarkable low-cost processability, so that the discotic liquid crystal molecules become an ideal organic semiconductor material, and have wide application prospects in Organic Field Effect Transistors (OFETs), organic Light Emitting Diodes (OLEDs) and organic photovoltaic devices (OPVs). To date, no document or patent reports the application of discotic liquid crystal small molecule/carbon nano tube composite materials in the thermoelectric field.
The inventors have further studied and found that the large aromatic condensed nucleus in the discotic liquid crystal molecules is sp 2 Hybridization, likewise, the carbon atoms in the single-arm carbon nanotubes are sp 2 The same hybridization orbit is more favorable for pi-pi interaction between discotic liquid crystal molecules and single-arm carbon nanotubes, and meanwhile, the discotic liquid crystal molecules have strong self-assembly and charge transmission capacity, so that the composite material based on the discotic liquid crystal molecules and the single-arm carbon nanotubes shows higher electric conductivity and Seebeck coefficient, and further a high Power Factor (PF) is obtained, and meanwhile, the thermal conductivity of the composite thermoelectric material after the composition is reduced, so that excellent thermoelectric performance is obtained.
Specifically, an embodiment of the present invention provides a composite thermoelectric material, wherein the composite thermoelectric material includes: the liquid crystal display comprises discotic liquid crystal molecules and single-arm carbon nanotubes, wherein the discotic liquid crystal molecules are attached to the single-arm carbon nanotubes;
the discotic liquid crystal molecules consist of discotic cores and a plurality of side chains connected with the peripheries of the discotic cores, and the structural general formula of the discotic liquid crystal molecules is shown as follows:
wherein the disc-shaped nucleus is polycyclic aromatic hydrocarbon, and the side chain is an alkyl side chain.
The embodiment of the invention provides a novel composite thermoelectric material obtained by compositing discotic liquid crystal molecules and single-arm carbon nanotubes, wherein the discotic liquid crystal molecules are attached to the single-wall carbon nanotubes. Besides higher power factor, the composite thermoelectric material has good flexibility and certain mechanical properties, so that the organic thermoelectric film material is expected to be applied to flexible wearable thermoelectric equipment. Compared with the traditional inorganic thermoelectric material, the preparation method of the composite thermoelectric material is simple, easy to realize, low in cost and easy to process and form.
The discotic liquid crystal molecule provided by the embodiment of the invention has a planar or approximately planar discotic core at the molecular center, and a plurality of flexible side chains are connected to the periphery of the core, wherein the side chains are alkyl side chains, the side chains can be the same or different, and the number of the side chains can be 4, 6 or 8. The discotic liquid crystal molecules have a distinct ordered state between liquid and crystalline states, i.e. the liquid crystalline state, which has both liquid-like mobility and crystal-like anisotropy.
In one embodiment, the polycyclic aromatic hydrocarbon is selected from one of the following structural formulas:
namely, the polycyclic aromatic hydrocarbon is one of the polycyclic aromatic hydrocarbons such as benzophenanthrene, azabenzophenanthrene, dibenzoperylene, hexabenzocoronene and the like.
In one embodiment, the alkyl side chain has the general molecular formula-C n H 2n+1 Wherein n has a value of 6-20;
the alkyl side chain is directly connected with the disc-shaped core; alternatively, the alkyl side chain is linked to the discotic core with an ether linkage, thioether linkage, ester linkage, amide linkage.
In one embodiment, in the composite thermoelectric material, the mass ratio of the discotic liquid crystal molecules to the single-arm carbon nanotubes is (1-9): 10.
the embodiment of the invention provides a preparation method of a composite thermoelectric material, which comprises the following steps:
s10, dispersing the single-arm carbon nanotubes in an organic solvent, and uniformly stirring to obtain a single-arm carbon nanotube solution;
s20, adding discotic liquid crystal molecules into the single-arm carbon nanotube solution, and uniformly stirring to obtain a mixed solution;
s30, taking the mixed solution on a substrate, and naturally airing to obtain the composite thermoelectric material.
In step S10, the single-arm carbon nanotubes are dispersed in an organic solvent, and stirred until the single-arm carbon nanotubes are pasty and uniformly dispersed, thereby obtaining a single-arm carbon nanotube solution.
In one embodiment, the organic solvent is one or more of chlorobenzene, dichlorobenzene, toluene, tetrahydrofuran, chloroform, and the like.
In one embodiment, the stirring is ultrasonic stirring for a period of 3 to 12 hours.
In step S20, in one embodiment, ultrasonic agitation is used until discotic liquid crystal molecules are uniformly dispersed.
In one embodiment, in the mixed solution, the mass of the discotic liquid crystal molecules is 10-90% of the mass of the single-arm carbon nanotubes.
In step S30, in one embodiment, a pipette is used to take the mixed solution on a substrate with a certain area, and the mixed solution is naturally dried to obtain the composite thermoelectric material of the discotic liquid crystal molecules and the single-arm carbon nanotubes.
In one embodiment, the step of taking the mixed solution on a substrate includes: taking 100-500 mu L of the mixed solution with the area of 1 multiplied by 1cm 2 Or 1.5X1.5 cm 2 Is provided.
In one embodiment, the substrate is a glass substrate or the like, but is not limited thereto.
The invention is further illustrated by the following specific examples.
Example 1
The discotic liquid crystal molecule is HAT6, the structural formula is shown in figure 1, which is purchased in Synthon ChemicalsGmbH & Co.KG, and the characterization method comprises the following steps:
(1) Carrying out a polarizing microscope test on discotic liquid crystal molecules HAT6 to obtain a liquid crystal phase texture thereof;
(2) And performing differential scanning calorimetric test on discotic liquid crystal molecules HAT6 to obtain the liquid crystal phase range.
Example 2
The preparation method of the SWCNT/HAT6 composite thermoelectric material comprises the following steps:
5mg of single-arm carbon nanotubes and 5mL of chlorobenzene were placed in a 10mL glass bottle, and the glass bottle was placed in an ultrasonic machine for about 3 hours under ultrasound, and finally the single-arm carbon nanotubes were uniformly dispersed in a paste form. Then, the discotic liquid crystal molecules HAT6 in example 1 were weighed according to the mass ratio of single-walled carbon nanotubes (SWCNT) to discotic liquid crystal molecules HAT6 of 1:0.25,1:0.5,1:1,1:4, namely, the weighed compounds HAT6 were 1.25mg, 2.5mg, 5mg and 20mg, respectively, and added into glass bottles of uniformly dispersed single-walled carbon nanotube solutions. And (5) putting the glass bottle into an ultrasonic machine again, continuing ultrasonic until the discoid liquid crystal molecules are uniformly dispersed, and obtaining a mixed solution. Finally, 250. Mu.L of the uniformly dispersed mixed solution was applied to the washed glass sheet (1.5X1.5 cm) 2 ) And naturally airing to obtain the tube composite thermoelectric material for thermoelectric test.
Example 3
Performance characterization of discotic liquid crystal molecules HAT6, performance characterization of SWCNT/HAT6 composite thermoelectric material and p-type pure single-walled carbon nanotube material and thermoelectric performance test:
1. the discotic liquid crystal molecule HAT6 passed the zeiss polarization microscope test, and as shown in fig. 2, the apparent liquid crystal texture was seen.
2. The discotic liquid crystal molecule HAT6 was tested by a differential thermal analyzer (model DSC-Q200, manufactured by TA corporation in united states), and the liquid crystal phase range was 67.72-98.82 ℃ as shown in fig. 3.
3. Four different proportions of SWCNT/HAT6 composite thermoelectric materials and pure single-arm carbon nanotube films were tested by laser confocal Raman spectroscopy (model provia, manufactured by Renidhaw Inc. of England). The laser source for detection was 514.5nm. The raman spectra of four different ratios of SWCNT/HAT6 composite thermoelectric materials and pure single-arm carbon nanotube films are shown in fig. 4. The G peak and the D peak of the composite thermoelectric material added with the discotic liquid crystal molecule HAT6 have almost no displacement change, which indicates that the added HAT6 does not damage the structure of the original SWCNT. The decrease in intensity in the RBM (radial respiration mode) band of the SWCNT/HAT6 composite thermoelectric material suggests that the discotic liquid crystal molecules HAT6 and SWCNTs are well composited. The raman spectral characteristics of the composite thermoelectric material are consistent with the thermoelectric data results at normal temperature.
4. Four different proportions of SWCNT/HAT6 composite thermoelectric materials and pure single-arm carbon nanotube films were tested by Bruker D8 advanced X-ray diffractometer, and XRD results are shown in FIG. 5. The SWCNT/HAT6 composite thermoelectric material shows a diffraction peak profile similar to that of a discotic liquid crystal molecule HAT6, and the peak value of the diffraction peak profile is slightly shifted towards a large angle direction, so that stronger interaction occurs between the diffraction peak profile and the discotic liquid crystal molecule HAT6, the enhancement of the Seebeck coefficient of the composite thermoelectric material is facilitated, but the interpenetrating network structure of a pure carbon tube is broken by excessive HAT6, and the conductivity of the composite thermoelectric material is reduced. This is consistent with the thermoelectric results of the observed SWCNT/HAT6 composite thermoelectric materials.
5. The surface of the composite thermoelectric material with different composite ratios was scanned in magnification by a Hitachi SU-70 field emission scanning electron microscope, and the results are shown in FIGS. 6 a-6 d. It is apparent that the compound HAT6 is attached to the network of single-walled carbon nanotubes as white granular crystals and its number and size increase with increasing composite ratio.
6. Thermoelectric performance tests of SWCNT/HAT6 composite thermoelectric materials with different composite ratios were performed by a Jia instrument through an MRS-3 thin film thermoelectric test system, and the results are shown in FIGS. 7-9. Compared with pure carbon tubes, the Seebeck coefficient of the composite thermoelectric material at room temperature is doubled, and the variation along with the HAT6 content is not great; whereas the conductivity decreases significantly with increasing HAT6 content. Therefore, the power factor of the composite thermoelectric material reaches the highest value at the mass ratio of SWCNT/HAT6 of 1:0.25, which is 408 mu Wm -1 K -2 。
In summary, compared with the traditional inorganic thermoelectric material, the novel liquid crystal/carbon nano tube composite thermoelectric material provided by the invention has high Seebeck coefficient, conductivity and power factor, good flexibility and certain mechanical property, so that the novel liquid crystal/carbon nano tube composite thermoelectric material is expected to be applied to flexible wearable thermoelectric equipment. Compared with the traditional inorganic thermoelectric material, the preparation method is simple and easy to realize, low in cost and easy to process and form.
It is to be understood that the invention is not limited in its application to the examples described above, but is capable of modification and variation in light of the above teachings by those skilled in the art, and that all such modifications and variations are intended to be included within the scope of the appended claims.
Claims (7)
1. A composite thermoelectric material, the composite thermoelectric material comprising: the liquid crystal display comprises discotic liquid crystal molecules and single-arm carbon nanotubes, wherein the discotic liquid crystal molecules are attached to the single-arm carbon nanotubes;
the discotic liquid crystal molecules consist of discotic cores and a plurality of side chains connected with the peripheries of the discotic cores, and the structural general formula of the discotic liquid crystal molecules is shown as follows:
；
wherein the disc-shaped nucleus is polycyclic aromatic hydrocarbon, and the side chain is an alkyl side chain;
the polycyclic aromatic hydrocarbon is selected from one of the following structural formulas:
；
the mass ratio of the discotic liquid crystal molecules to the single-arm carbon nanotubes is (1-9): 10;
the molecular general formula of the alkyl side chain is-C n H 2n+1 Wherein n has a value of 6-20;
the alkyl side chain is directly connected with the disc-shaped core; alternatively, the alkyl side chain is linked to the discotic core with an ether linkage, thioether linkage, ester linkage, amide linkage.
2. A method of preparing the composite thermoelectric material of claim 1, comprising the steps of:
dispersing the single-arm carbon nano tube in an organic solvent, and uniformly stirring to obtain a single-arm carbon nano tube solution;
adding discotic liquid crystal molecules into the single-arm carbon nanotube solution, and uniformly stirring to obtain a mixed solution;
and (3) taking the mixed solution on a substrate, and naturally airing to obtain the composite thermoelectric material.
3. The method for preparing a composite thermoelectric material according to claim 2, wherein the organic solvent is one or more of chlorobenzene, dichlorobenzene, toluene, tetrahydrofuran, and chloroform.
4. The method of preparing a composite thermoelectric material according to claim 2, wherein in the step of dispersing the single-arm carbon nanotubes in the organic solvent and stirring uniformly, the stirring is ultrasonic stirring, and the time of ultrasonic stirring is 3-12 hours.
5. The method for preparing a composite thermoelectric material according to claim 2, wherein the mass of the discotic liquid crystal molecules in the mixed solution is 10-90% of the mass of the single-arm carbon nanotubes.
6. The method of claim 2, wherein the step of disposing the mixed solution on a substrate comprises: taking 100-500 mu L of the mixed solution with the area of 1 multiplied by 1cm 2 Or 1.5X1.5 cm 2 Is provided.
7. The method of manufacturing a composite thermoelectric material according to claim 2, wherein the substrate is a glass substrate.
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