A PEDOT:PSS thermoelectric composite thin film, its preparation method and application

Abstract

This invention discloses a PEDOT:PSS thermoelectric composite film, its preparation method, and its application, belonging to the field of flexible thermoelectric material preparation technology. SnCl2·H2O particles are dissolved in distilled water and stirred. Flake NaOH is then added and stirred again. The mixture is then subjected to a hydrothermal reaction. The hydrothermal product is centrifuged, washed, and dried to obtain SnO2 nanosheets. A polar solvent, SnO2 nanosheets, and distilled water are sequentially added to a PEDOT:PSS aqueous solution, stirred, and shaken to obtain a PEDOT:PSS mixture. This mixture is then dropped onto a glass substrate and dried to obtain a PEDOT:PSS thermoelectric composite film. The film is then placed on a hot plate, with metal wires placed at both ends. Conductive silver paste is dropped at the contact points between the metal wires and the film. Heating solidifies the conductive silver paste, thus connecting the metal wires and the PEDOT:PSS thermoelectric composite film. After simulated sunlight irradiation… S Increase, s The decline was less than 2%, and the result was... s and S Decoupled PEDOT:PSS thermoelectric composite films realize the thermoelectric composite film s and S Decoupling.

Description

Technical Field

[0001] This invention belongs to the field of flexible thermoelectric thin film material preparation technology, specifically relating to a PEDOT:PSS thermoelectric composite thin film, its preparation method, and its application. Background Technology

[0002] Thermoelectric materials are semiconductor materials capable of directly converting heat energy into electrical energy. Polymer semiconductor materials such as poly(3,4-ethylenedioxythiophene) and poly(styrene sulfonic acid) (PEDOT:PSS) possess advantages such as intrinsically low thermal conductivity, low cost, and high mechanical flexibility, and are therefore widely studied in the field of flexible thermoelectric materials. Because polymers have low intrinsic thermal conductivity, their thermoelectric properties are typically expressed using the power factor (…). PF To evaluate: PF = σS 2 , s and S These are electrical conductivity and Seebeck coefficient, respectively. Due to the intrinsic low conductivity of PEDOT:PSS... s and low S The problem leads to the intrinsic properties of PEDOT:PSS semiconductor thermoelectric thin films. PF Lower.

[0003] Composite inorganic second phases are a common strategy for improving the thermoelectric performance of PEDOT:PSS. The energy filtering effect generated at the two-phase interface can usually improve the power factor, that is, filtering low-energy carriers at the interface while allowing high-energy carriers to pass through the two-phase interface. Therefore, the power factor can be controlled by selecting an inorganic composite phase with a suitable work function. s and S This allows for the optimization of thermoelectric performance. However, the energy filtering effect in thermoelectric composite materials still cannot be decoupled. s and S In other words, improving one parameter comes at the cost of decreasing another parameter to varying degrees. Through balancing and optimizing these two parameters, a higher power factor is ultimately achieved. Illumination is frequently used to improve the electronic properties of semiconductor materials, but currently, neither visible nor ultraviolet light irradiation can effectively decouple thermoelectric composite materials. s and S Two parameters (J. Appl. Phys. 114(17) (2013), Nano Energy 49 (2018), J. Mater. Chem. A 10(2) (2022), J. Mater. Chem. A 9(31) (2021)), and the above literature also has problems such as the high content of the composite phase leading to difficulty in dispersion, complex preparation methods, and limited light band (visible light or ultraviolet light) leading to limitations in practical applications.

[0004] Regarding the conductivity of PEDOT:PSS thermoelectric composite films ( s ) and Seebeck coefficient ( S The strong coupling problem of PEDOT:PSS thermoelectric composite films requires finding a new preparation method to decouple the conductivity and Seebeck coefficient. Summary of the Invention

[0005] In order to overcome the shortcomings of the prior art, the present invention aims to provide a PEDOT:PSS thermoelectric composite film, its preparation method and application, so as to solve the problem of strong coupling between conductivity and Seebeck coefficient in PEDOT:PSS thermoelectric composite film, that is, to improve the Seebeck coefficient without affecting conductivity.

[0006] To achieve the above objectives, the present invention employs the following technical solution:

[0007] This invention discloses a method for preparing a PEDOT:PSS thermoelectric composite thin film, comprising the following steps:

[0008] 1) Dissolve SnCl2·H2O particles in the first portion of distilled water, stir for the first time, then add flake NaOH, stir for the second time, perform hydrothermal reaction, centrifuge and wash, and dry for the first time to obtain SnO2 nanosheets;

[0009] 2) Polar solvent, SnO2 nanosheets and second part of distilled water are added to PEDOT:PSS aqueous solution in sequence. After a third stirring and shaking, PEDOT:PSS mixture is obtained. PEDOT:PSS mixture is dropped onto substrate and dried for a second time to obtain PEDOT:PSS composite film.

[0010] 3) Place the PEDOT:PSS composite film on a hot plate, place metal wires at both ends of the PEDOT:PSS composite film, and drop conductive silver paste at the contact point between the metal wires and the PEDOT:PSS composite film. After heating, the conductive silver paste will solidify, and the metal wires and the PEDOT:PSS composite film will be connected. After being irradiated with simulated sunlight, the PEDOT:PSS thermoelectric composite film is obtained.

[0011] PEDOT: PSS thermoelectric composite film s and S Decoupling, S Increase and s The decrease was less than 2%.

[0012] Preferably, in step 1), the ratio of SnCl2·H2O particles, the first portion of distilled water, and flake NaOH is (0.1~1) g: (10~100) mL: (0.02~1) g.

[0013] Preferably, in step 1), the first stirring speed is 500~1000 rpm and the first stirring time is 10~60 min; the second stirring speed is 500~1000 rpm and the second stirring time is 20~60 min.

[0014] Preferably, in step 1), the hydrothermal reaction temperature is 100~200 °C and the hydrothermal reaction time is 12~36 h;

[0015] The conditions for centrifugal washing are as follows: several centrifugal washes are performed using distilled water and anhydrous ethanol, respectively.

[0016] The temperature for the first drying is 30~60 °C, and the drying time is 12~24 h.

[0017] Preferably, in step 2), the volume ratio of PEDOT:PSS aqueous solution to the second part of distilled water is 1:(1~5); the volume fraction of polar solvent is 1~6 vol%; the polar solvent is DMSO, ethanol, methanol or ethylene glycol; and the mass fraction of SnO2 nanosheets is 0~1 wt%.

[0018] Preferably, in step 2), the third stirring rate is 500~1000 rpm, and the third stirring time is 10~36 h;

[0019] The oscillation rate is 800~4000 rpm, and the oscillation time is 1~3 h.

[0020] Preferably, in step 2), the substrate is a glass slide. After the glass slide is pre-cleaned, it is soaked in acetone and isopropanol in sequence and then sonicated for 15 min. The content of the PEDOT:PSS mixture added to the glass slide is 200-1000 μL.

[0021] The second drying temperature is 30~80 °C, and the second drying time is 5~24 h.

[0022] Preferably, in step 3), the metal wire is copper wire, silver wire, or iron wire;

[0023] The curing temperature of conductive silver paste is 80~150 °C;

[0024] The power of simulated sunlight exposure is 100~600 W, and the duration is 100~500 s.

[0025] This invention also discloses a PEDOT:PSS thermoelectric composite film, prepared using the above-described method; when the mass percentage of SnO2 nanosheets is 0-1 wt%, the Seebeck coefficient of the PEDOT:PSS thermoelectric composite film is 13.3-65.30 μV·K.-1 Its electrical conductivity is 379.5~428 S·cm -1 The power factor is 7~182.5 μW·m. -1 ·K -2 .

[0026] The present invention also discloses the application of the PEDOT:PSS thermoelectric composite thin film prepared by the above preparation method in semiconductor thermoelectric devices, temperature sensors and wearable electronic devices.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] This invention discloses a PEDOT:PSS thermoelectric composite film, its preparation method, and its applications. The invention employs an ultra-low content of nano-sized SnO2 combined with PEDOT:PSS. The ultra-low content of the inorganic composite phase ensures uniform dispersion. Compared to micron-sized SnO2, nano-sized SnO2 has a smaller band gap, allowing electrons to more easily transition from the valence band to the conductivity band under simulated sunlight irradiation. Furthermore, the conduction band of nano-sized SnO2 is higher than the Fermi level of PEDOT:PSS, allowing electrons in the SnO2 nanosheets to rapidly transfer to PEDOT:PSS, leading to electron gain and dedoping in PEDOT:PSS. This significantly increases the Seebeck coefficient, while the conductivity of the composite film decreases by less than 2% during this process. Therefore, the decoupling of conductivity and Seebeck coefficient is achieved, greatly optimizing the power factor of the PEDOT:PSS thermoelectric composite film. Specifically, the desired SnO2 nanosheets are first prepared via a hydrothermal method. The better dispersion of nano-sized SnO2 in the PEDOT:PSS solution facilitates the preparation of a more uniform and stable composite film. A method for directly compositing PEDOT:PSS with ultra-low content nano-sized SnO2 was employed. The SnO2 nanosheets were well dispersed in the PEDOT:PSS solution, forming a monolayer PEDOT:PSS thermoelectric composite film. This preparation method is simple, and the PEDOT:PSS thermoelectric composite film exhibited good dispersion under simulated sunlight irradiation. S Increase, and s The decline was less than 2%, which truly achieved s and S Decoupling. This invention improves the Seebeck coefficient of organic thermoelectric thin films without affecting electrical conductivity. Under simulated sunlight irradiation, the Seebeck coefficient of the composite film increases significantly, while the electrical conductivity... s It remains unchanged. In fact, due to... s and S There is a strong coupling relationship between them, and during the optimization process, there is always a trend of one parameter decreasing while another parameter increases, leading to the PEDOT:PSS thermoelectric composite film... PF Optimization is quite difficult. However, this invention successfully overcomes this challenge and achieves... s and S Effective decoupling is a characteristic that is particularly important for the application of thermoelectric materials.

[0029] Furthermore, compared to other works, this invention preferably uses ultra-low content nanoscale SnO2 nanosheets, with a content between 0.1 and 1 wt%, which can be well dispersed in PEDOT:PSS solution. The SnO2 nanosheets can be replaced with other nanoscale oxides or other compounds with similar band structures or band gaps to SnO2.

[0030] Furthermore, stirring and vigorous shaking of the mixed solution is beneficial for the thorough mixing of SnO2 nanosheets and PEDOT:PSS solution.

[0031] Furthermore, drying at a low temperature of 30~80 °C is beneficial for film formation and increases the adhesion between the film and the glass sheet.

[0032] Furthermore, the light source used is a simulated sunlight source, which has a wider range of adaptability.

[0033] This invention also discloses the PEDOT:PSS thermoelectric composite film prepared by the above method; when the mass percentage of SnO2 nanosheets is 0~1 wt%, the Seebeck coefficient of the PEDOT:PSS thermoelectric composite film is 13.3~65.30 μV·K. -1 Its electrical conductivity is 379.5~428 S·cm -1 The power factor is 7~182.5 μW·m. -1 ·K -2 When the SnO2 nanosheet content is 0.25 wt%, the Seebeck coefficient of the PEDOT:PSS thermoelectric composite film can reach a maximum of 65.30 μV·K when placed under simulated sunlight. -1 The power factor is 182.5 μW·m. -1 ·K -2 By irradiating the PEDOT:PSS thermoelectric composite film with simulated sunlight, S Increase and s A decrease of less than 2% achieved s and S The decoupling of these components is of great theoretical and practical significance for improving and controlling the power factor of thermoelectric materials by utilizing illumination. Attached Figure Description

[0034] Figure 1 The Seebeck coefficient of PEDOT:PSS thermoelectric composite films with different SnO2 contents in this invention varies under light and darkness.

[0035] Figure 2 The change in conductivity of PEDOT:PSS thermoelectric composite films with different SnO2 contents under light and darkness in this invention;

[0036] Figure 3 This refers to the variation of the power factor of PEDOT:PSS thermoelectric composite films with different SnO2 contents under light and darkness in this invention. Detailed Implementation

[0037] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] Unless otherwise specified, all embodiments and preferred embodiments mentioned herein can be combined to form new technical solutions.

[0039] Unless otherwise specified, all the technical features and preferred features mentioned herein can be combined to form new technical solutions.

[0040] In this invention, unless otherwise specified, percentage (%) or parts refer to weight percentage or parts relative to the composition.

[0041] In this invention, unless otherwise specified, the components involved or their preferred components can be combined to form new technical solutions.

[0042] In this invention, unless otherwise specified, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are both real numbers. For example, the numerical range "6~22" indicates that all real numbers between "6~22" have been listed in this document, and "6~22" is simply a shortened representation of these numerical combinations.

[0043] The "scope" disclosed in this invention can be in the form of a lower limit and an upper limit, and can be one or more lower limits and one or more upper limits, respectively.

[0044] In this invention, the term "and / or" as used herein refers to any combination of one or more of the associated listed items, as well as all possible combinations, and includes such combinations.

[0045] In this invention, unless otherwise stated, the various reactions or operation steps may be performed sequentially or in a particular order. Preferably, the reaction methods described herein are performed sequentially.

[0046] Unless otherwise stated, the technical and scientific terms used herein have the same meanings as those familiar to those skilled in the art. Furthermore, any methods or materials similar to or equivalent to those described herein may also be used in this invention.

[0047] This invention discloses a method for preparing a PEDOT:PSS thermoelectric composite thin film, and the specific experimental steps are as follows:

[0048] 1) Weigh 0.1–1 g of SnCl₂·H₂O granules into a beaker and add 10–100 mL of distilled water. Stir for the first time at a speed of 500–1000 rpm for 10–60 min. Then add 0.02–1 g of flake NaOH and stir a second time at a speed of 500–1000 rpm for 20–60 min to obtain mixture A.

[0049] 2) Place 10-50 mL of mixture A in a hydrothermal reactor and carry out a hydrothermal reaction at 100-200 °C for 12-36 h to obtain mixture B. Wash mixture B several times by centrifugation with distilled water and anhydrous ethanol, and then dry to obtain the desired SnO2 nanosheets. The drying temperature of the centrifuged sample is 30-60 °C, and the drying time is 12-24 h.

[0050] 3) Add a polar solvent, SnO2 nanosheets, and distilled water sequentially to a PEDOT:PSS aqueous solution and stir to obtain mixture C. Vigorously agitate mixture C to ensure complete homogeneity, obtaining PEDOT:PSS mixture D. The volume ratio of PEDOT:PSS aqueous solution to distilled water is 1:(1~5), the volume fraction of the added polar solvent is 1~6 vol%, and the polar solvent can be DMSO, ethanol, methanol, or ethylene glycol, etc.; the mass fraction of the added SnO2 nanosheets is 0~1 wt%. The stirring rate is 500~1000 rpm, the stirring time is 10~36 h, and the oscillation rate is 800~4000 rpm, the oscillation time is 1~3 h.

[0051] 4) The PEDOT:PSS mixture D was dropped onto a pre-prepared glass slide and dried at low temperature to obtain a PEDOT:PSS composite film. The content of the PEDOT:PSS mixture D dropped onto the glass slide was 200-1000 μL. The low-temperature drying temperature was 30-80 °C, and the drying time was 5-24 h.

[0052] 5) The prepared PEDOT:PSS composite film was placed on a hot plate, and metal wires were placed at both ends of the film. Conductive silver paste was dripped at the contact points between the metal wires and the film. Heating was used to cure the silver paste, thus connecting the metal wires and the film, ultimately forming a simple device. The device was then irradiated with simulated sunlight, and tests revealed… S Increase and s The decline was less than 2%. ， get s and S Decoupled PEDOT:PSS thermoelectric composite film.

[0053] The metal wires used are copper, silver, or iron wires. The temperature for curing the silver paste is 80-150 °C, the light power is 100-600 W, and the light exposure time is 100-500 s.

[0054] SnCl2·H2O granules are a commercial product, with specifications of AR and 98%. Specific information is shown in Table 1.

[0055] Table 1 Product Specifications of SnCl2·H2O Granules

[0056]

[0057] Among them, the flake NaOH is a commercial product, with specifications of AR, 96% flakes. Specific information is shown in Table 2:

[0058] Table 2 Product Specifications of Flake NaOH

[0059]

[0060] Among them, PEDOT:PSS aqueous solution is a commercial product with the specification Clevious PH1000. Specific information is shown in Table 3.

[0061] Table 3 Product Specifications of PEDOT:PSS Aqueous Solution

[0062]

[0063] The DMSO solution is a commercial product, specification AR, and details are shown in Table 4.

[0064] Table 4 Product Specifications of DMSO Solution

[0065]

[0066] The PEDOT:PSS thermoelectric composite film prepared by the above method of the present invention exhibits a Seebeck coefficient of up to 65.30 μV·K under simulated sunlight irradiation when the SnO2 mass fraction is 0.25 wt%. -1 The conductivity of the composite film changed by less than 2% before and after illumination, and the conductivity after illumination was 428 S·cm. -1 The final power factor is 182.5 μW·m. -1 ·K -2 Under simulated sunlight irradiation, the Seebeck coefficient of the composite film was significantly improved, while the electrical conductivity changed by less than 2% before and after irradiation, thus achieving decoupling of electrical conductivity and Seebeck coefficient. This has important theoretical and practical significance for using light irradiation to improve and control the power factor of thermoelectric materials.

[0067] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0068] Example 1

[0069] A method for preparing a PEDOT:PSS thermoelectric composite thin film, the specific steps of which are as follows:

[0070] 1) Weigh 0.113 g of SnCl2·H2O granules into a beaker and add 40 mL of distilled water. Stir for the first time at 840 rpm for 10 min. Then add 0.024 g of flake NaOH and stir a second time at 840 rpm for 20 min. The final mixture is solution A.

[0071] 2) 40 mL of mixture A was placed in a hydrothermal reactor and subjected to a hydrothermal reaction at 190 °C for 30 h, resulting in mixture B. Mixture B was washed several times by centrifugation with distilled water and anhydrous ethanol, and then dried to obtain the desired SnO2 nanosheets. The centrifuged sample was dried at 60 °C for 24 h.

[0072] 3) DMSO solution and distilled water were added sequentially to the PEDOT:PSS aqueous solution and stirred to obtain mixture C. Mixture C was then vigorously shaken to ensure complete homogenization, resulting in PEDOT:PSS mixture D. The volume ratio of PEDOT:PSS aqueous solution to distilled water was 1:1, the volume fraction of added DMSO was 5 vol%, the stirring speed was 840 rpm, the stirring time was 24 h, and the shaking speed was 3000 rpm for 1 h.

[0073] 4) The PEDOT:PSS mixture D was dropped onto a pre-prepared glass slide and dried at low temperature to obtain a PEDOT:PSS composite film. The content of the PEDOT:PSS mixture D dropped onto the glass slide was 1000 μL. The low-temperature drying temperature was 40°C, and the drying time was 5 h.

[0074] 5) The prepared PEDOT:PSS composite film was placed on a hot plate, and metal wires were placed at both ends of the film. Conductive silver paste was dripped at the contact points between the metal wires and the film. Heating was used to cure the silver paste, thus connecting the metal wires and the film to form a simple device. The device was then irradiated with simulated sunlight. The metal wires were copper wires, the silver paste curing temperature was 100 °C, the light power was 500 W, and the irradiation time was 200 s.

[0075] The Seebeck coefficient of the PEDOT:PSS thermoelectric composite film prepared by the method in Example 1 is 13.3 μV·K. -1 The conductivity is 394.2 S·cm. -1 The power factor is 7 μW·m -1 ·K -2 .

[0076] Example 2

[0077] A method for preparing a PEDOT:PSS thermoelectric composite thin film, the specific steps of which are as follows:

[0078] 1) Weigh 0.113 g of SnCl2·H2O granules into a beaker and add 40 mL of distilled water. Stir for the first time at 840 rpm for 10 min. Then add 0.024 g of flake NaOH and stir a second time at 840 rpm for 20 min. The final mixture is solution A.

[0079] 2) 40 mL of mixture A was placed in a hydrothermal reactor and subjected to a hydrothermal reaction at 190 °C for 30 h, resulting in mixture B. Mixture B was washed several times by centrifugation with distilled water and anhydrous ethanol, and then dried to obtain the desired SnO2 nanosheets. The centrifuged sample was dried at 60 °C for 24 h.

[0080] 3) DMSO solution, SnO2 nanosheets, and distilled water were added sequentially to a PEDOT:PSS aqueous solution and stirred to obtain mixture C. Mixture C was then vigorously agitated to ensure complete homogenization, yielding PEDOT:PSS mixture D. The volume ratio of PEDOT:PSS aqueous solution to distilled water was 1:1, the volume fraction of added DMSO was 5 vol%, and the mass fraction of added SnO2 nanosheets was 0.1 wt%. The stirring rate was 840 rpm for 24 h, and the agitation rate was 3000 rpm for 1 h.

[0081] 4) The PEDOT:PSS mixture D was dropped onto a pre-prepared glass slide and dried at low temperature to obtain a PEDOT:PSS composite film. The content of the PEDOT:PSS mixture D dropped onto the glass slide was 1000 μL. The low-temperature drying temperature was 40°C, and the drying time was 5 h.

[0082] 5) Place the prepared PEDOT:PSS composite film on a hot plate, and place metal wires at both ends of the PEDOT:PSS composite film. Apply conductive silver paste to the contact points between the metal wires and the PEDOT:PSS composite film, and heat to cure the conductive silver paste, thus connecting the metal wires and the PEDOT:PSS composite film to form a simple device. Irradiate the resulting device with simulated sunlight for testing. s and S Finally obtained s and S Decoupled PEDOT:PSS thermoelectric composite film. The metal wire is copper wire, the silver paste is cured at 100 °C, the light power is 500 W, and the light exposure time is 200 s.

[0083] The Seebeck coefficient of the PEDOT:PSS thermoelectric composite film prepared by the method in Example 2 is 22.4 μV·K. -1 The conductivity is 402.3 S·cm -1 The power factor is 20.2 μW·m. -1 ·K -2 .

[0084] Example 3

[0085] A method for preparing a PEDOT:PSS thermoelectric composite thin film, the specific steps of which are as follows:

[0086] 1) Weigh 0.113 g of SnCl2·H2O granules into a beaker and add 40 mL of distilled water. Stir for the first time at 840 rpm for 10 min. Then add 0.024 g of flake NaOH and stir a second time at 840 rpm for 20 min. The final mixture is solution A.

[0087] 2) 40 mL of mixture A was placed in a hydrothermal reactor and subjected to a hydrothermal reaction at 190 °C for 30 h, resulting in mixture B. Mixture B was washed several times by centrifugation with distilled water and anhydrous ethanol, and then dried to obtain the desired SnO2 nanosheets. The centrifuged sample was dried at 60 °C for 24 h.

[0088] 3) DMSO solution, SnO2 nanosheets, and distilled water were added sequentially to a PEDOT:PSS aqueous solution and stirred to obtain mixture C. Mixture C was then vigorously agitated to ensure complete homogenization, yielding PEDOT:PSS mixture D. The volume ratio of PEDOT:PSS aqueous solution to distilled water was 1:1, the volume fraction of added DMSO was 5 vol%, and the mass fraction of added SnO2 nanosheets was 0.25 wt%. The stirring rate was 840 rpm for 24 h, and the agitation rate was 3000 rpm for 1 h.

[0089] 4) The PEDOT:PSS mixture D was dropped onto a pre-prepared glass slide and dried at low temperature to obtain a PEDOT:PSS composite film. The content of the PEDOT:PSS mixture D dropped onto the glass slide was 1000 μL. The low-temperature drying temperature was 40°C, and the drying time was 5 h.

[0090] 5) Place the prepared PEDOT:PSS composite film on a hot plate, and place metal wires at both ends of the PEDOT:PSS composite film. Apply conductive silver paste to the contact points between the metal wires and the PEDOT:PSS composite film, and heat to cure the conductive silver paste, thus connecting the metal wires and the PEDOT:PSS composite film to form a simple device. Irradiate the resulting device with simulated sunlight for testing. s and S Finally obtained s and SDecoupled PEDOT:PSS thermoelectric composite film. The metal wire is copper wire, the silver paste is cured at 100 °C, the light power is 500 W, and the light exposure time is 200 s.

[0091] The Seebeck coefficient of the PEDOT:PSS thermoelectric composite film prepared by the method in Example 3 is 65.3 μV·K. -1 The electrical conductivity is 428 S·cm -1 The power factor is 182.5 μW·m. -1 ·K -2 .

[0092] Example 4

[0093] A method for preparing a PEDOT:PSS thermoelectric composite thin film, the specific steps of which are as follows:

[0094] 1) Weigh 0.113 g of SnCl2·H2O granules into a beaker and add 40 mL of distilled water. Stir for the first time at 840 rpm for 10 min. Then add 0.024 g of flake NaOH and stir a second time at 840 rpm for 20 min. The final mixture is solution A.

[0095] 2) 40 mL of mixture A was placed in a hydrothermal reactor and subjected to a hydrothermal reaction at 190 °C for 30 h, resulting in mixture B. Mixture B was washed several times by centrifugation with distilled water and anhydrous ethanol, and then dried to obtain the desired SnO2 nanosheets. The centrifuged sample was dried at 60 °C for 24 h.

[0096] 3) DMSO solution, SnO2 nanosheets, and distilled water were added sequentially to a PEDOT:PSS aqueous solution and stirred to obtain mixture C. Mixture C was then vigorously agitated to ensure complete homogenization, yielding PEDOT:PSS mixture D. The volume ratio of PEDOT:PSS aqueous solution to distilled water was 1:1, the volume fraction of added DMSO was 5 vol%, and the mass fraction of added SnO2 nanosheets was 0.5 wt%. The stirring rate was 840 rpm for 24 h, and the agitation rate was 3000 rpm for 1 h.

[0097] 4) The PEDOT:PSS mixture D was dropped onto a pre-prepared glass slide and dried at low temperature to obtain a PEDOT:PSS composite film. The content of the PEDOT:PSS mixture D dropped onto the glass slide was 1000 μL. The low-temperature drying temperature was 40°C, and the drying time was 5 h.

[0098] 5) Place the prepared PEDOT:PSS composite film on a hot plate, and place metal wires at both ends of the PEDOT:PSS composite film. Apply conductive silver paste to the contact points between the metal wires and the PEDOT:PSS composite film, and heat to cure the conductive silver paste, thus connecting the metal wires and the PEDOT:PSS composite film to form a simple device. Irradiate the resulting device with simulated sunlight for testing. s and S Finally obtained s and S Decoupled PEDOT:PSS thermoelectric composite film. The metal wire is copper wire, the silver paste is cured at 100 °C, the light power is 500 W, and the light exposure time is 200 s.

[0099] The Seebeck coefficient of the PEDOT:PSS thermoelectric composite film prepared by the method in Example 4 is 37.9 μV·K. -1 The electrical conductivity is 379.5 S·cm. -1 The power factor is 54.5 μW·m. -1 ·K -2 .

[0100] Example 5

[0101] A method for preparing a PEDOT:PSS thermoelectric composite thin film, the specific steps of which are as follows:

[0102] 1) Weigh 0.113 g of SnCl2·H2O granules into a beaker and add 40 mL of distilled water. Stir for the first time at 840 rpm for 10 min. Then add 0.024 g of flake NaOH and stir a second time at 840 rpm for 20 min. The final mixture is solution A.

[0103] 2) 40 mL of mixture A was placed in a hydrothermal reactor and subjected to a hydrothermal reaction at 190 °C for 30 h, resulting in mixture B. Mixture B was washed several times by centrifugation with distilled water and anhydrous ethanol, and then dried to obtain the desired SnO2 nanosheets. The centrifuged sample was dried at 60 °C for 24 h.

[0104] 3) DMSO solution, SnO2 nanosheets, and distilled water were added sequentially to a PEDOT:PSS aqueous solution and stirred to obtain mixture C. Mixture C was then vigorously shaken to ensure complete homogenization, yielding PEDOT:PSS mixture D. The volume ratio of PEDOT:PSS aqueous solution to distilled water was 1:1, the volume fraction of added DMSO was 5 vol%, and the mass fraction of added SnO2 nanosheets was 1 wt%. The stirring rate was 840 rpm for 24 h, and the shaking rate was 3000 rpm for 1 h.

[0105] 4) The PEDOT:PSS mixture D was dropped onto a pre-prepared glass slide and dried at low temperature to obtain a PEDOT:PSS composite film. The content of the PEDOT:PSS mixture D dropped onto the glass slide was 1000 μL. The low-temperature drying temperature was 40°C, and the drying time was 5 h.

[0106] 5) Place the prepared PEDOT:PSS composite film on a hot plate, place metal wires at both ends of the PEDOT:PSS composite film, and drop conductive silver paste at the contact points between the metal wires and the PEDOT:PSS composite film. Heat the film to cure the conductive silver paste, thus connecting the metal wires and the PEDOT:PSS composite film. Simulate sunlight irradiation and test the film. s and S Finally obtained s and S Decoupled PEDOT:PSS thermoelectric composite film. The metal wire is copper wire, the silver paste is cured at 100 °C, the light power is 500 W, and the light exposure time is 200 s.

[0107] The Seebeck coefficient of the PEDOT:PSS thermoelectric composite film prepared by the method in Example 5 is 28.6 μV·K. -1 The conductivity is 427.3 S·cm. -1 The power factor is 35 μW·m -1 ·K -2 .

[0108] Example 6

[0109] A method for preparing a PEDOT:PSS thermoelectric composite thin film, the specific steps of which are as follows:

[0110] 1) Weigh 0.1 g of SnCl2·H2O granules into a beaker and add 10 mL of distilled water. Stir for the first time at 500 rpm for 60 min. Then add 0.02 g of flake NaOH and stir a second time at 500 rpm for 60 min. The final mixture is solution A.

[0111] 2) Place 10 mL of mixture A in a hydrothermal reactor and carry out a hydrothermal reaction at 100 °C for 12 h to obtain mixture B. Wash mixture B several times by centrifugation with distilled water and anhydrous ethanol, and then dry to obtain the desired SnO2 nanosheets. The centrifuged sample was dried at 30 °C for 12 h.

[0112] 3) Ethylene glycol solution, SnO2 nanosheets, and distilled water were added sequentially to a PEDOT:PSS aqueous solution and stirred to obtain mixture C. Mixture C was then vigorously agitated to ensure complete homogenization, yielding PEDOT:PSS mixture D. The volume ratio of PEDOT:PSS aqueous solution to distilled water was 1:2, the volume fraction of added ethylene glycol was 1 vol%, and the mass fraction of added SnO2 nanosheets was 0.8 wt%. The stirring rate was 500 rpm for 10 h, and the agitation rate was 800 rpm for 3 h.

[0113] 4) The PEDOT:PSS mixture D was dropped onto a pre-prepared glass slide and dried to obtain a PEDOT:PSS thermoelectric composite film. The content of the PEDOT:PSS mixture D dropped onto the glass was 200 μL. The low-temperature drying temperature was 30 °C, and the drying time was 24 h.

[0114] 5) Place the prepared PEDOT:PSS composite film on a hot plate, and place metal wires at both ends of the PEDOT:PSS composite film. Apply conductive silver paste to the contact points between the metal wires and the PEDOT:PSS composite film, and heat to cure the conductive silver paste, thus connecting the metal wires and the PEDOT:PSS composite film to form a simple device. Irradiate the resulting device with simulated sunlight for testing. s and S Finally obtained s and S Decoupled PEDOT:PSS thermoelectric composite film. The metal wire is silver wire, the silver paste is cured at 80 °C, the light power is 100 W, and the light exposure time is 100 s.

[0115] Example 7

[0116] A method for preparing a PEDOT:PSS thermoelectric composite thin film, the specific steps of which are as follows:

[0117] 1) Weigh 1 g of SnCl2·H2O granules into a beaker and add 100 mL of distilled water. Stir for the first time at 1000 rpm for 20 min. Then add 1 g of flake NaOH and stir a second time at 1000 rpm for 40 min. The final mixture is solution A.

[0118] 2) 50 mL of mixture A was placed in a hydrothermal reactor and subjected to a hydrothermal reaction at 200 °C for 36 h, resulting in mixture B. Mixture B was washed several times by centrifugation with distilled water and anhydrous ethanol, and then dried to obtain the desired SnO2 nanosheets. The centrifuged sample was dried at 50 °C for 20 h.

[0119] 3) Methanol solution, SnO2 nanosheets, and distilled water were added sequentially to a PEDOT:PSS aqueous solution and stirred to obtain mixture C. Mixture C was then vigorously shaken to ensure complete homogenization, yielding PEDOT:PSS mixture D. The volume ratio of PEDOT:PSS aqueous solution to distilled water was 1:5, the volume fraction of added methanol was 6 vol%, and the mass fraction of added SnO2 nanosheets was 0.9 wt%. The stirring rate was 1000 rpm for 36 h, and the shaking rate was 4000 rpm for 2 h.

[0120] 4) The PEDOT:PSS mixture D was dropped onto a pre-prepared glass slide and dried to obtain a PEDOT:PSS thermoelectric composite film. The content of the PEDOT:PSS mixture D dropped onto the glass was 800 μL. The low-temperature drying temperature was 80 °C, and the drying time was 20 h.

[0121] 5) Place the prepared PEDOT:PSS composite film on a hot plate, and place metal wires at both ends of the PEDOT:PSS composite film. Apply conductive silver paste to the contact points between the metal wires and the PEDOT:PSS composite film, and heat to cure the conductive silver paste, thus connecting the metal wires and the PEDOT:PSS composite film to form a simple device. Irradiate the resulting device with simulated sunlight for testing. s and S Finally obtained s and S Decoupled PEDOT:PSS thermoelectric composite film. The metal wire is iron wire, the silver paste is cured at 150 °C, the light power is 600 W, and the light exposure time is 500 s.

[0122] Example 8

[0123] A method for preparing a PEDOT:PSS thermoelectric composite thin film, the specific steps of which are as follows:

[0124] 1) Weigh 0.5 g of SnCl2·H2O granules into a beaker and add 50 mL of distilled water. Stir for the first time at 600 rpm for 40 min. Then add 0.8 g of flake NaOH and stir a second time at 800 rpm for 50 min. The final mixture is solution A.

[0125] 2) 30 mL of mixture A was placed in a hydrothermal reactor and subjected to a hydrothermal reaction at 150 °C for 20 h, resulting in mixture B. Mixture B was washed several times by centrifugation with distilled water and anhydrous ethanol, and then dried to obtain the desired SnO2 nanosheets. The centrifuged sample was dried at 40 °C for 15 h.

[0126] 3) Ethanol solution, SnO2 nanosheets, and distilled water were added sequentially to a PEDOT:PSS aqueous solution and stirred to obtain mixture C. Mixture C was then vigorously shaken to ensure complete homogenization, yielding PEDOT:PSS mixture D. The volume ratio of PEDOT:PSS aqueous solution to distilled water was 1:3, the volume fraction of added ethanol was 4 vol%, and the mass fraction of added SnO2 nanosheets was 0.7 wt%. The stirring rate was 900 rpm for 20 h, and the shaking rate was 1000 rpm for 1.5 h.

[0127] 4) The PEDOT:PSS mixture D was dropped onto a pre-prepared glass slide and dried to obtain a PEDOT:PSS thermoelectric composite film. The content of the PEDOT:PSS mixture D dropped onto the glass was 500 μL. The low-temperature drying temperature was 60 °C, and the drying time was 15 h.

[0128] 5) Place the prepared PEDOT:PSS composite film on a hot plate, and place metal wires at both ends of the PEDOT:PSS composite film. Apply conductive silver paste to the contact points between the metal wires and the PEDOT:PSS composite film, and heat to cure the conductive silver paste, thus connecting the metal wires and the PEDOT:PSS composite film to form a simple device. Irradiate the resulting device with simulated sunlight for testing. s and S Finally obtained s and SDecoupled PEDOT:PSS thermoelectric composite film. The metal wire is silver wire, the silver paste is cured at 120 °C, the light power is 400 W, and the light exposure time is 300 s.

[0129] See Figure 1 The figure shows the Seebeck coefficient of PEDOT:PSS thermoelectric composite films with different SnO2 contents under light and darkness in this invention. As can be seen from the figure, as the SnO2 content increases from 0 wt% to 1 wt%, the Seebeck coefficient of the composite film ranges from 13.3 to 65.30 μV·K. -1 The variation between these values; for the prepared PEDOT:PSS thermoelectric composite film, in Example 1, when the SnO2 content was 0 wt%, the Seebeck coefficient under illumination was 13.3 μV·K. -1 The Seebeck coefficient in darkness is 12.5 μV·K. -1 In Example 2, when the SnO2 content was 0.1 wt%, the Seebeck coefficient under illumination was 22.4 μV·K. -1 The Seebeck coefficient in darkness is 10.0 μV·K. -1 In Example 3, when the SnO2 content was 0.25 wt%, the Seebeck coefficient under illumination was 65.3 μV·K. -1 The Seebeck coefficient under darkness is 14.6 μV·K. -1 In Example 4, when the SnO2 content was 0.5 wt%, the Seebeck coefficient under illumination was 37.9 μV·K. -1 The Seebeck coefficient in darkness is 18.6 μV·K. -1 In Example 5, when the SnO2 content was 1 wt%, the Seebeck coefficient under illumination was 28.6 μV·K. -1 The Seebeck coefficient in darkness is 16.0 μV·K. -1 .

[0130] See Figure 2 The figure shows the change in conductivity of PEDOT:PSS thermoelectric composite films with different SnO2 contents under light and darkness in this invention. As can be seen from the figure, as the SnO2 content increases from 0 wt% to 1 wt%, the conductivity of the composite film ranges from 379.5 to 428 S·cm. -1 The conductivity varies between these values; for the prepared PEDOT:PSS thermoelectric composite film, in Example 1, when the SnO2 content is 0 wt%, the conductivity under illumination is 394.2 S·cm. -1 The conductivity in darkness is 395.0 S·cm. -1 In Example 2, when the SnO2 content was 0.1 wt%, the conductivity under illumination was 402.3 S·cm.-1 The conductivity in darkness is 402.6 S·cm. -1 In Example 3, when the SnO2 content was 0.25 wt%, the conductivity under illumination was 428.0 S·cm. -1 The conductivity in darkness is 430.2 S·cm. -1 In Example 4, when the SnO2 content was 0.5 wt%, the conductivity under illumination was 379.5 S·cm. -1 The conductivity in darkness is 382.0 S·cm. -1 In Example 5, when the SnO2 content was 1 wt%, the conductivity under illumination was 427.3 S·cm. -1 The conductivity in darkness is 433.0 S·cm. -1 .

[0131] See Figure 3 The figure shows the power factor variation of PEDOT:PSS thermoelectric composite films with different SnO2 contents under light and darkness in this invention. As can be seen from the figure, as the SnO2 content increases from 0 wt% to 1 wt%, the power factor of the composite film ranges from 7 to 182.5 μW·m. -1 ·K -2 The variation between these values; for the prepared PEDOT:PSS thermoelectric composite film, in Example 1, when the SnO2 content was 0 wt%, the power factor under illumination was 7 μW·m. -1 ·K -2 The power factor in darkness is 6.2 μW·m. -1 ·K -2 In Example 2, when the SnO2 content was 0.1 wt%, the power factor under illumination was 20.2 μW·m. -1 ·K -2 The power factor in darkness is 4.0 μW·m. -1 ·K -2 In Example 3, when the SnO2 content was 0.25 wt%, the power factor under illumination was 182.5 μW·m. -1 ·K -2 The power factor in darkness is 9.2 μW·m. -1 ·K -2 In Example 4, when the SnO2 content was 0.5 wt%, the power factor under illumination was 54.5 μW·m. -1 ·K -2 The power factor in darkness is 13.2 μW·m. -1 ·K -2 In Example 5, when the SnO2 content was 1 wt%, the power factor under illumination was 35.0 μW·m.-1 ·K -2 The power factor in darkness is 11.1 μW·m. -1 ·K -2 .

[0132] In summary, this invention provides a method for preparing a PEDOT:PSS thermoelectric composite film. The method involves sequentially adding a polar solvent, ultra-low content SnO2 nanosheets, and distilled water to a PEDOT:PSS aqueous solution, followed by stirring and vigorous agitation of the mixture. The uniformly mixed solution is then dropped onto a glass slide, and after drying, a PEDOT:PSS thermoelectric composite film is obtained. Under simulated sunlight irradiation, this composite film exhibits a power factor as high as 182.5 μW·m. -1 ·K -2 SnO2 nanosheets were prepared by hydrothermal method and then composited with PEDOT:PSS. The resulting PEDOT:PSS thermoelectric composite film exhibited [significant improvement] under simulated sunlight irradiation. S A significant increase, and its s A decrease of less than 2% achieved s and S This decoupling is of significant theoretical and practical importance for improving and controlling the power factor of thermoelectric materials using illumination, and it is beneficial for their application in semiconductor thermoelectric devices, temperature sensors, and wearable electronic devices.

[0133] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a PEDOT:PSS thermoelectric composite film, characterized by, Comprising the following steps: 1) SnCl2·H2O particles are dissolved in a first portion of distilled water, first stirring is performed, then flaky NaOH is added, second stirring is performed, after hydrothermal reaction, centrifugal washing is performed, after first drying, SnO2 nanosheets are prepared; the amount ratio of the SnCl2·H2O particles, the first portion of distilled water and the flaky NaOH is (0.1-1) g:(10-100) mL:(0.02-1) g; the temperature of the hydrothermal reaction is 100-200 °C, and the time of the hydrothermal reaction is 12-36 h; 2) A polar solvent, SnO2 nanosheets and a second portion of distilled water are sequentially added to a PEDOT:PSS aqueous solution, after third stirring and oscillation, a PEDOT:PSS mixed solution is obtained, the PEDOT:PSS mixed solution is dropped on a substrate, after second drying, a PEDOT:PSS composite thin film is obtained; the volume fraction of the polar solvent is 1-6 vol%; the polar solvent is DMSO, ethanol, methanol or ethylene glycol; the mass fraction of the SnO2 nanosheets is 0-1 wt%; 3) The PEDOT:PSS composite thin film is placed on a hot plate, metal wires are respectively placed at both ends of the PEDOT:PSS composite thin film, conductive silver paste is dropped at the contact position between the metal wires and the PEDOT:PSS composite thin film, after heating, the conductive silver paste is solidified, the metal wires and the PEDOT:PSS composite thin film are connected, after simulated sunlight irradiation, a PEDOT:PSS thermoelectric composite thin film is obtained; The PEDOT:PSS thermoelectric composite film has σ and S decoupled, S increased while σ decreases less than 2%.

2. The method for preparing the PEDOT:PSS thermoelectric composite thin film according to claim 1, characterized in that, In step 1), the first stirring rate is 500-1000 rpm, and the first stirring time is 10-60 min; the second stirring rate is 500-1000 rpm, and the second stirring time is 20-60 min.

3. The method for preparing the PEDOT:PSS thermoelectric composite thin film according to claim 1, characterized in that, In step 1), the centrifugal washing condition is that distilled water and anhydrous ethanol are used for several times of centrifugal washing, respectively; The first drying temperature is 30-60 °C, and the first drying time is 12-24 h.

4. The method for preparing the PEDOT:PSS thermoelectric composite thin film according to claim 1, characterized in that, In step 2), the volume ratio of the PEDOT:PSS aqueous solution to the second portion of distilled water is 1:(1-5).

5. The method for preparing the PEDOT:PSS thermoelectric composite thin film according to claim 1, characterized in that, In step 2), the third stirring rate is 500-1000 rpm, and the third stirring time is 10-36 h; The oscillation rate is 800-4000 rpm, and the oscillation time is 1-3 h.

6. The method for preparing the PEDOT:PSS thermoelectric composite thin film according to claim 1, characterized in that, In step 2), the substrate is a glass sheet, the glass sheet is prewashed, then soaked in acetone and isopropanol successively, and then ultrasonic treated for 15 min; the PEDOT:PSS mixed solution dropped on the glass sheet contains 200-1000 μL; The second drying temperature is 30-80 °C, and the second drying time is 5-24 h.

7. The method for preparing the PEDOT:PSS thermoelectric composite thin film according to claim 1, characterized in that, In step 3), the metal wire is a copper wire, a silver wire or an iron wire; The conductive silver paste solidification temperature is 80-150 °C; The simulated sunlight irradiation power is 100-600 W, and the time is 100-500 s.

8. A PEDOT:PSS thermoelectric composite film, characterized by, The PEDOT:PSS thermoelectric composite film has a Seebeck coefficient of 13.3-65.30 muV·K, an electrical conductivity of 379.5-428 S·cm, and a power factor of 7-182.5 muW·m·K when the mass percentage of the SnO2 nanosheet is 0-1 wt%. -1 -1 -1 -2 .​​​ 9. Use of the PEDOT:PSS thermoelectric composite film prepared by the method of any one of claims 1-7 in a semiconductor thermoelectric device, a temperature sensor, or a wearable electronic device.

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