Thermoelectric film with micro-crack structure constructed based on PEDOT: PSS and polyaniline and preparation method thereof

Abstract

The invention relates to the technical field of thermoelectric materials, in particular to a micro-crack structure thermoelectric thin film constructed based on PEDOT: PSS and polyaniline and a preparation method thereof.The preparation method comprises the following steps that a PEDOT: PSS raw material is selected, filtered and then dispersed in absolute ethyl alcohol, and uniform PEDOT: PSS dispersion liquid is obtained; the preparation method comprises the following steps: selecting a polyaniline raw material, and dispersing in absolute ethyl alcohol to obtain a stable and uniform polyaniline suspension; a vacuum suction filtration device is adopted, the specific vacuum degree is controlled, PEDOT: PSS dispersion liquid, polyaniline suspension liquid and PEDOT: PSS dispersion liquid are sequentially added, and a sandwich structure composite film precursor is formed through layered suction filtration. The method can be realized by adopting conventional vacuum filtration equipment, the microcrack structure is controllable, the thermoelectric performance can be optimized by adjusting the number of layers and the concentration, the prepared film has good flexibility and environmental stability, and the thermoelectric performance of the PEDOT: PSS-based composite material is improved.

Description

A thermoelectric thin film with microcrack structure based on PEDOT:PSS and polyaniline and its preparation method Technical Field

[0001] This invention relates to the field of thermoelectric materials technology, specifically to a thermoelectric thin film with a microcrack structure based on PEDOT:PSS and polyaniline, and its preparation method. Background Technology

[0002] Thermoelectric materials enable the direct conversion between thermal and electrical energy, and have broad application prospects in fields such as building curtain walls and waste heat recovery. Conductive polymers such as PEDOT:PSS (poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate) have become a research hotspot for flexible thermoelectric materials due to their excellent flexibility, solution processability, and thermoelectric properties. However, the thermoelectric properties of PEDOT:PSS itself (such as Seebeck coefficient and power factor) still need to be improved.

[0003] Polyaniline (PANI), as another conductive polymer, has a high Seebeck coefficient and good environmental stability. Studies have shown that by constructing microcrack structures, carrier transport paths can be effectively controlled and thermoelectric performance can be improved. However, there is currently a lack of a simple and controllable method to construct composite microcrack structures of PEDOT:PSS and polyaniline.

[0004] In summary, it is necessary to propose a thermoelectric thin film with a microcrack structure based on PEDOT:PSS and polyaniline and its preparation method to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a thermoelectric thin film with a microcrack structure based on PEDOT:PSS and polyaniline and its preparation method, so as to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: The present invention proposes a method for preparing a thermoelectric thin film with a microcrack structure based on PEDOT:PSS and polyaniline, comprising the following steps: S1. Selecting PEDOT:PSS raw material, dispersing it in anhydrous ethanol after filtration to obtain a uniform PEDOT:PSS dispersion; S2. Selecting polyaniline raw material, dispersing it in anhydrous ethanol to obtain a stable and uniform polyaniline suspension; S3. Using a vacuum filtration device, controlling a specific vacuum degree, sequentially adding the materials from step S1 to the device. The prepared PEDOT:PSS dispersion, the polyaniline suspension prepared in S2, and the PEDOT:PSS dispersion prepared in S1 were subjected to layered filtration to form a "PEDOT:PSS / polyaniline / PEDOT:PSS" sandwich structure composite membrane precursor; S4. The composite membrane precursor obtained in S3 and the carrier filter membrane were placed together on a heating stage, and the drying temperature and time were controlled to remove the solvent; S5. After the composite membrane dried in S4 was cooled to room temperature, the carrier filter membrane was peeled off using a special tool to obtain a thermoelectric thin film with a microcrack structure.

[0007] Preferably, the specific implementation process of S1 is as follows: S1.1. Select PEDOT:PSS, with a volume of 1.5mL; S1.2. Use a 0.22μm needle filter and a 5mL disposable sterile dispenser to pressurize and filter PEDOT:PSS to remove solid impurities; S1.3. Transfer the filtered PEDOT:PSS to a 50mL sterile test tube, add 10mL of anhydrous ethanol with a purity ≥99.7%, place it at room temperature of 20-25℃, and use an ultrasonic cell disruptor at 80W power to ultrasonically disperse it for 30 minutes to obtain a uniform PEDOT:PSS dispersion.

[0008] Preferably, the specific implementation process of S2 is as follows: S2.1. Select polyaniline with a weight average molecular weight of 5000-10000 and a dosage of 2mg; S2.2. Place the polyaniline in a 20mL sterile test tube, add 10mL of anhydrous ethanol with a purity ≥99.7%, place it at room temperature of 20-25℃, and use an ultrasonic cell disruptor with a power of 60W to ultrasonically disperse it for 40 minutes to form a stable and uniform polyaniline suspension with a concentration of 0.2mg / mL.

[0009] Preferably, the specific implementation process of S3 is as follows: S3.1. Construct a vacuum filtration device consisting of a vacuum pump, a 50mm diameter Buchner funnel, a 250mL filtration flask, a rubber stopper, and a gas delivery tube; S3.2. Lay a layer of nylon filter membrane with a pore size of 0.45μm and a diameter of 50mm at the bottom of the Buchner funnel; S3.3. Start the vacuum pump, adjust the system vacuum to 0.095MPa and maintain it stable; S3.4. First add the PEDOT:PSS dispersion prepared in S1 to the funnel, maintain a vacuum of 0.095MPa and filter for 20 minutes to form the bottom layer PE. DOT:PSS film; S3.5. Turn off the vacuum pump, slowly add the polyaniline suspension prepared in S2, restart the vacuum pump and maintain a vacuum degree of 0.095MPa, filter for 15 minutes to form the middle layer polyaniline film; S3.6. Turn off the vacuum pump again, add the PEDOT:PSS dispersion prepared in S1, start the vacuum pump and maintain a vacuum degree of 0.095MPa to filter for 20 minutes to form the top layer PEDOT:PSS film, and finally obtain the "PEDOT:PSS / polyaniline / PEDOT:PSS" sandwich structure composite membrane precursor.

[0010] Preferably, the specific implementation process of S4 is as follows: the nylon filter membrane carrying the composite membrane precursor is placed flat on the heating table, the heating temperature is set to 120°C, and it is kept warm and dried for 10 minutes to completely remove the anhydrous ethanol solvent in the composite membrane precursor.

[0011] Preferably, the specific implementation process of S5 is as follows: after the temperature of the heating table in S4 drops to room temperature of 20-25℃, a 12cm sterile stainless steel tweezer with passivated tip is used to apply a slight pulling force perpendicular to the surface of the nylon filter membrane at a 30° angle from the edge of the nylon filter membrane, peeling the composite membrane off the nylon filter membrane to obtain a thermoelectric thin film with a microcrack structure attached to the nylon membrane. During the peeling process, the film should be protected from damage.

[0012] Preferably, the microcrack structure obtained in step S5 forms a network distribution on the surface and cross-section of the thermoelectric thin film, with the width of the network microcracks being 50-200 nm and the spacing between adjacent microcracks being 1-5 μm.

[0013] The present invention also proposes a method for preparing a thermoelectric thin film with a microcrack structure based on PEDOT:PSS and polyaniline, wherein the thickness of the thermoelectric thin film is 20-50 μm.

[0014] Compared with the prior art, the beneficial effects of the present invention are: the preparation process of the present invention is simple and can be achieved using conventional vacuum filtration equipment; the microcrack structure is controllable; the thermoelectric performance can be optimized by adjusting the number of layers and concentration; the prepared film has good flexibility and environmental stability; the thermoelectric performance of PEDOT:PSS-based composite material is improved; and it has good application prospects. Detailed Implementation

[0015] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0016] In this embodiment, the present invention proposes a method for preparing a thermoelectric thin film with a microcrack structure based on PEDOT:PSS and polyaniline, comprising the following steps: S1. Selecting PEDOT:PSS raw material, dispersing it in anhydrous ethanol after filtration to obtain a uniform PEDOT:PSS dispersion; In a specific embodiment, the specific implementation process of S1 is as follows: S1.1. Selecting Heraeus Clevios PH1000 PEDOT:PSS, with a dosage of 1.5 mL; S1.2. Using a 0.22 μm needle filter and a 5 mL disposable sterile dispenser to pressurize and filter PEDOT:PSS to remove solid impurities; S1.3. Transferring the filtered PEDOT:PSS to a 50 mL sterile test tube, adding 10 mL of anhydrous ethanol with a purity ≥99.7%, placing it at room temperature of 20-25℃, and ultrasonically dispersing it for 30 minutes at 80 W using a SCIENTZ-IID ultrasonic cell disruptor to obtain a uniform PEDOT:PSS dispersion.

[0017] S2. Select polyaniline raw material and disperse it in anhydrous ethanol to obtain a stable and uniform polyaniline suspension. In a specific embodiment, the specific implementation process of S2 is as follows: S2.1. Select Aldrich 428157 polyaniline with a weight average molecular weight of 5000-10000 and a dosage of 2mg; S2.2. Place the polyaniline in a 20mL sterile test tube, add 10mL of anhydrous ethanol with a purity ≥99.7%, place it at room temperature of 20-25℃, and use a SCIENTZ-IID ultrasonic cell disruptor with a power of 60W to ultrasonically disperse it for 40 minutes to form a stable and uniform polyaniline suspension with a concentration of 0.2mg / mL.

[0018] S3. Using a vacuum filtration device, controlling a specific vacuum level, the PEDOT:PSS dispersion prepared in S1, the polyaniline suspension prepared in S2, and the PEDOT:PSS dispersion prepared in S1 are sequentially added to the device. Through layered filtration, a "PEDOT:PSS / polyaniline / PEDOT:PSS" sandwich-structured composite membrane precursor is formed. In a specific embodiment, the specific implementation process of S3 is as follows: S3.1. Construct a vacuum filtration device consisting of an SHB-III type circulating water multi-purpose vacuum pump, a 50mm diameter Buchner funnel, a 250mL filtration flask, a rubber stopper, and a gas delivery tube; S3.2. Lay a nylon filter membrane with a pore size of 0.45μm and a diameter of 50mm at the bottom of the Buchner funnel; S3.3. Start the vacuum pump and adjust the system vacuum level to... S3.4. First, add the PEDOT:PSS dispersion prepared in S1 to the funnel, maintain a vacuum of 0.095MPa and filter for 20 minutes to form the bottom layer PEDOT:PSS film; S3.5. Turn off the vacuum pump, slowly add the polyaniline suspension prepared in S2, restart the vacuum pump and maintain a vacuum of 0.095MPa, filter for 15 minutes to form the middle layer polyaniline film; S3.6. Turn off the vacuum pump again, add the PEDOT:PSS dispersion prepared in S1, start the vacuum pump and maintain a vacuum of 0.095MPa to filter for 20 minutes to form the top layer PEDOT:PSS film, and finally obtain the "PEDOT:PSS / polyaniline / PEDOT:PSS" sandwich structure composite membrane precursor.

[0019] S4. Place the composite membrane precursor obtained in S3 together with the carrier filter membrane on a heating table, control the drying temperature and time, and remove the solvent; in a specific embodiment, the specific implementation process of S4 is as follows: place the nylon filter membrane carrying the composite membrane precursor flat on the C-MAGHS7 heating table of Chengdu Huaheng Instrument Co., Ltd., set the heating temperature to 120℃, keep it warm and dry for 10 minutes to completely remove the anhydrous ethanol solvent in the composite membrane precursor.

[0020] S5. After the composite membrane in S4 has dried and cooled to room temperature, the carrier filter membrane is peeled off using a special tool to obtain a thermoelectric thin film with a microcrack structure.

[0021] In a specific embodiment, the specific implementation process of S5 is as follows: after the temperature of the heating table in S4 drops to room temperature of 20-25°C, a 12cm sterile stainless steel tweezer with passivated tip is used to apply a slight pulling force perpendicular to the surface of the nylon filter membrane at a 30° angle from the edge of the nylon filter membrane, peeling the composite membrane off the nylon filter membrane to obtain a thermoelectric thin film with microcrack structure attached to the nylon membrane. During the peeling process, the film should be protected from damage.

[0022] In a specific embodiment, the microcrack structure obtained in step S5 forms a network distribution on the surface and cross-section of the thermoelectric thin film. The width of the network microcracks is 50-200 nm, and the spacing between adjacent microcracks is 1-5 μm. This structure can regulate the carrier transport path and improve the Seebeck coefficient and power factor of the thermoelectric thin film.

[0023] It should also be noted that the density and distribution of the microcrack structure can be optimized by adjusting the concentration of the PEDOT:PSS dispersion in S1, the concentration of the polyaniline suspension in S2, or the number of times each layer is filtered in S3, so that the Seebeck coefficient of the thermoelectric film can reach ≥65μV / K and the power factor can reach ≥18μW / (m・K²).

[0024] A thermoelectric thin film with a thickness of 20-50 μm was prepared by a method for fabricating a microcrack structure based on PEDOT:PSS and polyaniline. The thermoelectric thin film was prepared according to the method of this invention, and repeatability verification experiments were conducted on multiple independent batches and multiple parallel samples per batch based on the method of this invention: a. Flexibility (180° bending) testing was performed with optimized film characteristic parameters, referring to the flexible electronic device bending test standard (IEC62890 series): Sample size: approximately 20 mm × 5 mm × 30 μm; Bending condition: 180° Reciprocating bending (1 time / second), bending radius 1mm; Test points: before bending, and after 100 bends, measuring Seebeck coefficient and power factor; Record the performance parameters of each sample, see Table 1: Table 1: Flexibility (180° bending) test data Batch Initial power factor (μW / (m・K²)) Power factor after 100 bends (μW / (m・K²)) Performance retention rate (%) Batch 1 18.4 16.9 9 1.9 Batch 2 18.5 17.0 9 1.9 Batch 3 18.3 16.8 9 1.8 Average 18.4 16.9 9 1.9 Table b. Environmental stability tests were conducted in accordance with the standards for damp heat exposure testing of polymer materials (ISO 8725 series), simulating normal temperature operating conditions: Environment: 25℃, relative humidity 50% (no light); Test points: initial state, thermoelectric performance was measured after 30 days of storage; Performance parameters for each sample were recorded, see Table 2: Table 2: Environmental Stability Test Data Batch Initial Power Factor (μW / (m・K²)) Power Factor after 30 Days (μW / (m・K²)) Performance Degradation Rate (%) Batch 1 18.4 17.7 3.8 Batch 2 18.5 17.8 3.8 Batch 3 18.3 17.6 3.8 Average 18.4 17.7 3.8 As can be seen from the data in Tables 1 and 2, the thermoelectric thin film prepared according to the preparation method of the present invention has good flexibility. After being bent 100 times at 180°, the thermoelectric performance retention rate is ≥90%. It also has excellent environmental stability. After being placed at 25°C and 50% relative humidity for 30 days, the thermoelectric performance decay is ≤5%.

[0025] In summary, the preparation process of this invention is simple and can be achieved using conventional vacuum filtration equipment. The microcrack structure is controllable, and the thermoelectric performance can be optimized by adjusting the number of layers and concentration. The prepared film has good flexibility and environmental stability, improves the thermoelectric performance of PEDOT:PSS-based composite materials, and has good application prospects.

[0026] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. This invention proposes a method for preparing a thermoelectric thin film with a microcrack structure based on PEDOT:PSS and polyaniline, characterized in that, Includes the following steps: S1. Select PEDOT:PSS raw material, filter it, and disperse it in anhydrous ethanol to obtain a uniform PEDOT:PSS dispersion; S2. Select polyaniline raw material, disperse it in anhydrous ethanol to obtain a stable and uniform polyaniline suspension; S3. Using a vacuum filtration device, control a specific vacuum degree, and sequentially add the PEDOT:PSS dispersion prepared in S1, the polyaniline suspension prepared in S2, and the PEDOT:PSS dispersion prepared in S1 to the device. After layered filtration, a "PEDOT:PSS / polyaniline / PEDOT:PSS" sandwich structure composite membrane precursor is formed. S4. Place the composite membrane precursor obtained in S3 together with the carrier filter membrane on a heating stage, control the drying temperature and time, and remove the solvent; S5. After the composite membrane dried in S4 has cooled to room temperature, peel off the carrier filter membrane using a special tool to obtain a thermoelectric thin film with a microcrack structure.

2. The method for preparing a thermoelectric thin film with a microcrack structure based on PEDOT:PSS and polyaniline according to claim 1, characterized in that, The specific implementation process of S1 is as follows: S1.

1. Select PEDOT:PSS with a volume of 1.5mL; S1.

2. Use a 0.22μm needle filter and a 5mL disposable sterile dispenser to pressurize and filter PEDOT:PSS to remove solid impurities. S1.

3. Transfer the filtered PEDOT:PSS to a 50mL sterile test tube, add 10mL of anhydrous ethanol with a purity ≥99.7%, place at room temperature of 20-25℃, and use an ultrasonic cell disruptor at 80W power to ultrasonically disperse for 30 minutes to obtain a uniform PEDOT:PSS dispersion.

3. The method for preparing a thermoelectric thin film with a microcrack structure based on PEDOT:PSS and polyaniline according to claim 2, characterized in that, The specific implementation process of S2 is as follows: S2.

1. Select polyaniline with a weight average molecular weight of 5000-10000 and a dosage of 2mg; S2.

2. Place the polyaniline in a 20mL sterile test tube, add 10mL of anhydrous ethanol with a purity ≥99.7%, place it at room temperature of 20-25℃, and use an ultrasonic cell disruptor with a power of 60W to ultrasonically disperse it for 40 minutes to form a stable and uniform polyaniline suspension with a concentration of 0.2mg / mL.

4. The method for preparing a thermoelectric thin film with a microcrack structure based on PEDOT:PSS and polyaniline according to claim 3, characterized in that, The specific implementation process of S3 is as follows: S3.

1. Construct a vacuum filtration device consisting of a vacuum pump, a 50mm diameter Buchner funnel, a 250mL filtration flask, a rubber stopper, and a gas delivery tube; S3.

2. Lay a nylon filter membrane with a pore size of 0.45μm and a diameter of 50mm at the bottom of the Buchner funnel; S3.

3. Start the vacuum pump, adjust the system vacuum to 0.095MPa and maintain it stable; S3.

4. First add the PEDOT:PSS dispersion prepared in S1 to the funnel, maintain a vacuum of 0.095MPa and filter for 20 minutes to form the bottom layer of PEDO. T: PSS film; S3.

5. Turn off the vacuum pump, slowly add the polyaniline suspension prepared in S2, restart the vacuum pump and maintain a vacuum degree of 0.095MPa, filter for 15 minutes to form the intermediate polyaniline film; S3.

6. Turn off the vacuum pump again, add the PEDOT:PSS dispersion prepared in S1, start the vacuum pump and maintain a vacuum degree of 0.095MPa to filter for 20 minutes to form the top PEDOT:PSS film, and finally obtain the "PEDOT:PSS / polyaniline / PEDOT:PSS" sandwich structure composite membrane precursor.

5. The method for preparing a thermoelectric thin film with a microcrack structure based on PEDOT:PSS and polyaniline according to claim 4, characterized in that, The specific implementation process of S4 is as follows: the nylon filter membrane carrying the composite membrane precursor is placed flat on the heating table, the heating temperature is set to 120°C, and it is kept warm and dried for 10 minutes to completely remove the anhydrous ethanol solvent in the composite membrane precursor.

6. The method for preparing a thermoelectric thin film with a microcrack structure based on PEDOT:PSS and polyaniline according to claim 5, characterized in that, The specific implementation process of S5 is as follows: After the temperature of the heating table in S4 drops to room temperature of 20-25℃, use 12cm sterile stainless steel tweezers with passivated tips to apply a slight pulling force perpendicular to the surface of the nylon filter membrane at a 30° angle from the edge of the nylon filter membrane, peel the composite membrane off the nylon filter membrane, and obtain a thermoelectric film with microcrack structure attached to the nylon membrane. Avoid damaging the film during the peeling process.

7. The method for preparing a thermoelectric thin film with a microcrack structure based on PEDOT:PSS and polyaniline according to claim 6, characterized in that, The microcrack structure obtained in step S5 forms a network distribution on the surface and cross-section of the thermoelectric thin film. The width of the network microcrack is 50-200 nm, and the spacing between adjacent microcracks is 1-5 μm.

8. The thermoelectric thin film prepared by the preparation method according to any one of claims 1-7, characterized in that, The thickness of the thermoelectric thin film is 20-50 μm.