CN111471196B

CN111471196B - Preparation method of PEDOT (polymer stabilized alumina)/PSS (copper sulfide)/Cu-doped silver selenide flexible composite film with high thermoelectric property

Info

Publication number: CN111471196B
Application number: CN201910064294.7A
Authority: CN
Inventors: 蔡克峰; 逯瑶
Original assignee: Tongji University
Current assignee: Tongji University
Priority date: 2019-01-23
Filing date: 2019-01-23
Publication date: 2021-10-08
Anticipated expiration: 2039-01-23
Also published as: CN111471196A

Abstract

The invention relates to a preparation method of a PEDOT/PSS/Cu doped silver selenide flexible composite film with high thermoelectric property, which comprises the following steps: (1): adding a selenium source and a reducing agent into a PEDOT PSS aqueous solution for reaction to synthesize a PEDOT PSS-coated selenium nanowire which is marked as PC-Se; (2): dispersing the PC-Se synthesized in the step (1) into an ethylene glycol solvent by taking the PC-Se as a template, adding a silver source and a copper source, reacting, and synthesizing the PC-Cu doped Ag with the core-shell structure₂A Se nanowire; (3): then doping the PC-Cu synthesized in the step (2) with Ag₂Dispersing the Se nanowire in absolute ethyl alcohol, performing suction filtration and drying to obtain a film, and performing cold pressing and hot pressing treatment in sequence to obtain a target product. Compared with the prior art, the preparation method is simple and feasible, and the prepared composite film has excellent thermoelectric property and the like.

Description

Preparation method of PEDOT (polymer stabilized alumina)/PSS (copper sulfide)/Cu-doped silver selenide flexible composite film with high thermoelectric property

Technical Field

The invention belongs to the technical field of thermoelectric materials, and relates to a preparation method of a PEDOT (Poly ethylene glycol Ether-butyl ether)/PSS (copper) doped silver selenide flexible composite film with high thermoelectric performance.

Background

Thermoelectric materials are a class of functional materials that can directly achieve interconversion between thermal energy and electrical energy. The thermoelectric power generation and refrigeration device prepared from the thermoelectric material has the advantages of simple structure, small volume, no need of moving parts, no abrasion, no noise, no pollution and the like. The thermoelectric material is used as an environment-friendly material and has wide application prospect.

The performance index of the thermoelectric material is generally measured by a dimensionless figure of merit ZT, and the expression is as follows:

ZT＝α2σT/κ

wherein: alpha is a Seebeck coefficient; σ is the conductivity; kappa is the thermal conductivity; t is the thermodynamic temperature.

Ag₂Se is a common thermoelectric material and belongs to a narrow bandgap semiconductor(0 ℃ C., energy gap 0.07eV), there was a phase transition at 133 ℃. Low temperature phase Ag₂Se has an orthorhombic structure and belongs to the semiconductor characteristic, high-temperature phase Ag₂Se has a cubic structure and belongs to a super ion conductor. Wherein, low temperature phase Ag₂Se has high electrical conductivity, high Seebeck coefficient and low thermal conductivity, and has excellent thermoelectric properties near room temperature. But the Ag currently prepared₂Se materials are inflexible and have a high thermal conductivity, which limits their application in flexible thermoelectric materials.

PSS aqueous solution has attracted great interest in the field of scientific research due to excellent conductivity and water solubility of PEDOT formed by doping conductive polymers such as Poly-3, 4-ethylene-dioxythiophene (PEDOT) and polystyrene sulfonic acid (PSS). The polymer-inorganic nano composite material is a novel composite material, the area of a two-phase interface is greatly increased due to nano-scale dispersion, and meanwhile, the small-size effect of the polymer-inorganic nano composite material also plays an important role in promoting the interaction between the two interfaces. The physical and chemical properties of the nano composite material are changed due to the fact that the dispersed phase size of the nano composite material is located in the boundary area of a macroscopic object and an atomic cluster, and the special change enables the nano composite material to become a hotspot of current research. At present, PEDOT, PSS and Ag are not found yet₂The technology research of Se compounding to prepare thermoelectric material film.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a preparation method of a PEDOT/PSS/Cu doped silver selenide flexible composite film with high thermoelectric property.

The purpose of the invention can be realized by the following technical scheme:

a preparation method of a PEDOT/PSS/Cu doped silver selenide flexible composite film with high thermoelectric property comprises the following steps:

(1): adding a selenium source and a reducing agent into a PEDOT PSS aqueous solution for reaction to synthesize a PEDOT PSS-coated selenium nanowire which is marked as PC-Se;

(2): dispersing the PC-Se synthesized in the step (1) into an ethylene glycol solvent by taking the PC-Se as a template, adding a silver source and a copper source, reacting, and synthesizing the PC-Cu doped Ag with the core-shell structure₂A Se nanowire;

(3): then doping the PC-Cu synthesized in the step (2) with Ag₂Dispersing the Se nanowire in absolute ethyl alcohol, performing suction filtration and drying to obtain a film, and performing cold pressing and hot pressing treatment in sequence to obtain a target product.

Further, in the step (1), the selenium source is SeO₂The reducing agent is ascorbic acid;

the adding amount ratio of the selenium source, the reducing agent and the PEDOT/PSS aqueous solution is 9 mmol: 36 mmol: 4 mL.

Further, in the step (2), the concentration of PC-Se in the glycol solvent is 2-50 mmol/L.

Further, in the step (2), the molar ratio of the total molar amount of the silver source and the copper source to the PC-Se is 1:2-5: 1;

the molar ratio of the silver source to the copper source is 1: 2-8: 1.

Further, in the step (2), the silver source is silver nitrate, and the copper source is copper sulfate.

Further, in the step (2), the reaction conditions are as follows: the reaction was continued with stirring at room temperature for 2-8 h.

Further, in the step (3), the drying process conditions are as follows: drying at 40-80 deg.C for 4-12 h.

Further, in the step (3), the cold pressing conditions are as follows: and cold pressing the dried film at room temperature under 10-20MPa for 1-5 min.

Further, in the step (3), the hot pressing conditions are as follows: the film after cold pressing is hot pressed for 30min at the temperature of 180 ℃ and 250 ℃ and under the pressure of 1-4 MPa.

Further, in the invention, in the step (2), the black precipitate obtained by the reaction is centrifuged for 1-5min at the rotating speed of 4000r/min, the supernatant is removed, then ethanol and deionized water are respectively and alternately added into the centrifuge tube, and the centrifugation and cleaning are continued for 1-5min at the rotating speed of 4000r/min to remove impurities, namely the PC-Cu doped Ag₂And (3) Se nanowire.

The filtration is to carry out vacuum filtration on the dispersion liquid by using a filter membrane (such as nylon, polyvinylidene fluoride and the like) as a substrate to form a membrane.

The reaction equation involved in the solution reaction process is as follows:

SeO₂+2C₆H₈O₆→Se+2C₆H₆O₆+2H₂O (1)

Cu²⁺+C₆H₈O₆→Cu+C₆H₆O₆+2H⁺ (2)

Ag⁺+C₆H₈O₆→Ag+C₆H₆O₆+2H⁺ (3)

2Ag+Se→Ag₂Se (4)

2Cu+Se→Cu₂Se (5)

Cu₂Se+Ag⁺→Cu²⁺+CuAgSe (6)

firstly, selenium dioxide is reduced into a nanowire-shaped selenium simple substance containing Cu under the action of a reducing agent (ascorbic acid)²⁺And Ag⁺The solution is reduced into copper and silver simple substances under the action of a reducing agent (ascorbic acid), and the copper and silver simple substances and the selenium simple substance form Ag respectively₂Se and Cu₂Se, and Cu₂Se in excess AgNO₃CuAgSe is easy to form in solution, so Ag exists in the generated nanowire₂Se and CuAgSe compounds. PSS serves as a polymer to coat the outer layer of the nanowire, so that the energy filtering effect and phonon scattering are enhanced. Thereby improving the power factor of the whole material and reducing the thermal conductivity.

Addition amount of ascorbic acid as reducing agent and SeO₂、Cu²⁺And Ag⁺The three raw materials are required to be completely reduced; PSS is added in the amount of ensuring that each nanowire can be completely coated, and the power factor is reduced if the consumption is excessive; a series of chemical reactions can be carried out at room temperature, and the complete reaction can be ensured within 4 hours; the pressure and temperature of the hot pressing are set to ensure that the sample is not stuck by the die, the higher the temperature is, the better the crystallinity of the sample is, and the higher the conductivity is, so that the thermoelectric property is better, but due to the limitation of equipment, the sample can be damaged if the temperature is too high.

Compared with the prior art, the invention has the following advantages:

(1) the preparation process is simple and easy to implement, low-temperature and short-time heat treatment is adopted, and energy is saved;

(2) the prepared composite film has strong binding force between the inorganic phase and the flexible substrate, has strong oxidation resistance and excellent flexibility, and is beneficial to use on flexible devices;

(3) the thermoelectric performance is excellent, and the highest power factor is achieved in the n-type materials.

Drawings

FIG. 1 shows a hot-pressed PEDOT-PSS/Cu doped Ag prepared according to the present invention₂XRD pattern of Se flexible composite film.

FIG. 2 shows a hot-pressed PEDOT-PSS/Cu doped Ag prepared according to the present invention₂SEM image of Se flexible composite film.

FIG. 3 shows a hot-pressed PEDOT-PSS/Cu doped Ag prepared according to the present invention₂Digital photo picture of Se flexible composite film.

Detailed Description

The invention is described in detail below with reference to the figures and specific embodiments. The present embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation manner and a specific operation process are given, but the scope of the present invention is not limited to the following embodiments.

In the following examples, the PC-Se nanowires used were prepared by the following method: get SeO₂And ascorbic acid in aqueous PEDOT PSS solution, SeO₂And the addition ratio of the ascorbic acid to the PEDOT/PSS aqueous solution is 9 mmol: 36 mmol: 4mL, reacting for 4h at room temperature, and synthesizing PEDOT, namely the selenium nanowire coated by PSS, namely the PC-Se nanowire. PEDOT PSS aqueous solution (pH1000) was purchased from Wuhan Xin science and technology, Inc. Others, unless otherwise specified, are indicated to be conventional commercial products or common processing techniques in the art.

Example 1

Preparation of PEDOT with high thermoelectric performance, PSS/Cu doped Ag₂The method of Se flexible composite film comprises the steps of dispersing 20ml of PC-Se nanowire in Ethylene Glycol (EG) (45mmol/L) and 0.9mmol of AgNO₃And 0.45mmol of CuSO₄Adding intoStirring in a beaker at room temperature for 2h, centrifuging at 4000r/min, extracting the obtained black precipitate, alternately adding deionized water and absolute ethyl alcohol, centrifuging at 4000r/min for 5min, cleaning to remove impurities, dispersing the carefully cleaned black target product in 15ml absolute ethyl alcohol, ultrasonically dispersing for 30min, and vacuum filtering with nylon filter membrane as substrate to obtain PEDOT, PSS/Cu doped Ag₂Se/nylon flexible film, and drying the obtained film in a vacuum drying oven at the temperature of 60 ℃ for 12 h. Cold pressing at 20MPa for 1min, hot pressing at 200 deg.C and 1MPa for 30min to obtain power factor of 3000 μ W m^-1K^-2PEDOT PSS/Cu doped Ag₂And (3) forming a Se flexible N-type composite film. FIG. 1 shows the hot-pressed PEDOT PSS/Cu doped Ag produced₂XRD pattern, Ag of Se flexible composite film₂The peaks of Se and CuAgSe correspond well to standard cards and show the orientation of (00 l). FIG. 2 shows the hot-pressed PEDOT prepared by PSS/Cu doping Ag₂In the SEM image of the Se flexible composite film, the prepared film has holes with sizes from nano-scale to micron-scale, which is beneficial to improving the flexibility and reducing the thermal conductivity. FIG. 3 shows the hot-pressed PEDOT PSS/Cu doped Ag produced₂Digital photo picture of Se flexible composite film, showing that it is flexible.

Table 1 shows the hot pressed PEDOT prepared under different Cu, Ag and Se source ratios in the invention, PSS/Cu doped Ag₂Thermoelectric property of the Se flexible composite film.

Example 2:

a method for preparing a silver selenide/nylon flexible composite film with high thermoelectric performance comprises the steps of dispersing 20ml of a PC-Se nanowire in Ethylene Glycol (EG) dispersion liquid (45mmol/L) and 1.2mmol of AgNO₃And 0.3mmol copper sulfate was added to the beakerStirring for 4 hours at room temperature, centrifuging at the rotating speed of 4000r/min, extracting the obtained black precipitate, alternately adding deionized water and absolute ethyl alcohol, centrifuging at the rotating speed of 4000r/min for 5min, cleaning to remove impurities, dispersing the carefully cleaned black target product in 15ml of absolute ethyl alcohol for ultrasonic dispersion for 30min after centrifugation, then taking a nylon filter membrane as a substrate, carrying out vacuum filtration to obtain a silver selenide/nylon flexible membrane, and drying the obtained membrane in a vacuum drying oven at the temperature of 60 ℃ for 12 hours. Cold pressing at 15MPa for 2min, hot pressing at 200 deg.C and 4MPa for 30min to obtain power factor of 2000 μ W m^-1K^-2PEDOT PSS/Cu doped Ag₂And the Se flexible N-type flexible composite film.

Example 3

Compared to example 1, most of them are the same except that in this example: the concentration of PC-Se in the ethylene glycol solvent is 2mmol/L, the molar ratio of the total molar amount of the silver source and the copper source to the PC-Se is 1:2, and the molar ratio of the silver source to the copper source is 1: 2.

Example 4

Compared to example 1, most of them are the same except that in this example: the concentration of the PC-Se in the glycol solvent is 2-50mmol/L, the molar ratio of the total molar amount of the silver source and the copper source to the PC-Se is 5:1, and the molar ratio of the silver source to the copper source is 8: 1.

Example 5

Compared with the embodiment 1, the method is mostly the same, except that in the embodiment, the conditions of the reaction of the PC-Se nanowire with the copper source and the silver source are as follows: the reaction was stirred continuously at room temperature for 2 h.

Example 6

Compared with the embodiment 1, the method is mostly the same, except that in the embodiment, the conditions of the reaction of the PC-Se nanowire with the copper source and the silver source are as follows: the reaction was stirred continuously at room temperature for 8 h.

Example 7

Compared with example 1, most of them are the same, except that in this example, the drying process conditions are as follows: drying at 40 deg.C for 12 h.

Example 8

Compared with example 1, most of them are the same, except that in this example, the drying process conditions are as follows: drying at 80 deg.C for 4 h.

Example 9

Most of the same is true compared to example 1, except that in this example, the cold pressing conditions are: the dried film was cold pressed at room temperature at 10MPa for 5 min.

Example 10

Most of the same is true compared to example 1, except that in this example, the cold pressing conditions are: the dried film was cold pressed at room temperature at 20MPa for 1 min.

Example 11

Most of the same is true compared to example 1, except that in this example, the hot pressing conditions are: and hot-pressing the cold-pressed film at 180 ℃ and 4MPa for 30 min.

Example 12

Most of the same is true compared to example 1, except that in this example, the hot pressing conditions are: and hot-pressing the cold-pressed film for 30min at 250 ℃ and under the pressure of 1 MPa.

The embodiments described above are described to facilitate an understanding and use of the invention by those skilled in the art. It will be readily apparent to those skilled in the art that various modifications to these embodiments may be made, and the generic principles described herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present invention is not limited to the above embodiments, and those skilled in the art should make improvements and modifications within the scope of the present invention based on the disclosure of the present invention.

Claims

1. A preparation method of a PEDOT/PSS/Cu doped silver selenide flexible composite film with high thermoelectric property is characterized by comprising the following steps:

(2): dispersing the PC-Se synthesized in the step (1) as a template in an ethylene glycol solvent, adding a silver source and a copper source, reacting, and synthesizingForm PC-Cu doped Ag with core-shell structure₂A Se nanowire;

(3): then doping the PC-Cu synthesized in the step (2) with Ag₂Dispersing Se nanowires in absolute ethyl alcohol, performing suction filtration and drying to obtain a film, and performing cold pressing and hot pressing treatment in sequence to obtain a target product;

in the step (1), the selenium source is SeO₂The reducing agent is ascorbic acid;

the adding amount ratio of the selenium source, the reducing agent and the PEDOT/PSS aqueous solution is 9 mmol: 36 mmol: 4 mL;

in the step (2), the silver source is silver nitrate, and the copper source is copper sulfate.

2. The preparation method of the PEDOT/PSS/Cu doped silver selenide flexible composite film with high thermoelectric performance according to claim 1, wherein the concentration of PC-Se in the glycol solvent in the step (2) is 2-50 mmol/L.

3. The preparation method of the PEDOT/PSS/Cu doped silver selenide flexible composite film with high thermoelectric property according to claim 1, wherein in the step (2), the molar ratio of the total molar amount of the silver source and the copper source to the PC-Se is 1:2-5: 1;

the molar ratio of the silver source to the copper source is 1: 2-8: 1.

4. The preparation method of the PEDOT/PSS/Cu doped silver selenide flexible composite film with high thermoelectric performance according to claim 1, wherein in the step (2), the reaction conditions are as follows: the reaction was continued with stirring at room temperature for 2-8 h.

5. The preparation method of the PEDOT/PSS/Cu doped silver selenide flexible composite film with high thermoelectric performance according to claim 1, wherein in the step (3), the drying process conditions are as follows: drying at 40-80 deg.C for 4-12 h.

6. The preparation method of the PEDOT/PSS/Cu doped silver selenide flexible composite film with high thermoelectric performance according to claim 1, wherein in the step (3), the cold pressing condition is as follows: and cold pressing the dried film at room temperature under 10-20MPa for 1-5 min.

7. The preparation method of the PEDOT/PSS/Cu doped silver selenide flexible composite film with high thermoelectric performance according to claim 1, wherein in the step (3), the hot pressing conditions are as follows: the film after cold pressing is hot pressed for 30min at the temperature of 180 ℃ and 250 ℃ and under the pressure of 1-4 MPa.