Wearable thermoelectric generator based on flexible corrugated tellurium film and preparation method thereof

Abstract

The invention provides a wearable thermoelectric generator based on a flexible corrugated tellurium film and a preparation method thereof, and the method comprises the steps: achieving a flexible tellurium-based film with p-type and n-type thermoelectric units alternately arranged on a single-layer tellurium film, and carrying out the bending, folding and packaging of the film; the exposed end of the pn junction of the wave-shaped tellurium film thermoelectric generator is arranged at the hot end, the other end of the pn junction is arranged in air, and it is guaranteed that the cold end and the hot end of the device generate temperature difference, so that multiple carriers of p-type and n-type semiconductors migrate from the hot end to the cold end, and thermoelectric force in the same direction is formed; at least pn pairs of thermoelectric units are arranged alternately, and when a plurality of pairs of thermoelectric units are connected in series, the stretchability of the device is remarkably enhanced. The power generation device can generate power in different common living heat sources such as human wrists, hot water cups and computer radiators, is low in cost, is simple and easy to reproduce, and is made of replaceable materials.

Description

Technical Field

[0001] The present invention belongs to the field of nano biosensors, and in particular relates to a wearable thermoelectric generator based on a flexible corrugated tellurium film and a preparation method thereof. Background Art

[0002] Wearable electronic devices have become a research hotspot in recent years due to their application prospects in the fields of communications, healthcare, motion detection, etc. Currently, wearable electronic products on the market mainly rely on electrochemical energy storage batteries for power supply, but are limited by battery life. Self-powered wearable electronic devices driven by human body heat through the thermoelectric effect are a promising solution that can directly convert waste heat into useful electrical energy. The principle of this Seebeck effect is that when there is a temperature difference between the two ends of the conductor, the majority carriers of both p-type and n-type semiconductors migrate from the hot end to the cold end, forming a current in the same direction. Therefore, thermoelectric generators based on the Seebeck effect have the advantages of high reliability, long life and maintenance-free, and have broad application prospects in the aerospace field, waste heat collection, and human body thermal energy collection.

[0003] However, current thermoelectric generators are limited by output voltage and power density, and their commercial applications are very limited. How to reasonably design the device structure to achieve high output performance while having high stretchability so that it is suitable for a variety of application scenarios has become an urgent problem for researchers to solve. Usually, people consider the design optimization of thermoelectric materials and device structures to achieve thermoelectric devices with high output performance and high stretchability. In terms of materials, the main focus is on improving the dimensionless thermoelectric figure of merit of thermoelectric materials. In terms of device structure, researchers have proposed the idea of ​​converting two-dimensional planar structures into three-dimensional structures. In recent years, studies have reported a variety of three-dimensional thermoelectric generators that utilize the vertical temperature difference on the skin surface, including wavy structures, spring structures, spiral structures, etc.

[0004] In the existing thin-film-based three-dimensional thermoelectric generator, a power of 10.02 W m - ², but it also uses complex processes and expensive equipment. In many cases, p-type and n-type tellurium-based films need to be prepared separately, and then the p-type and n-type thermoelectric films are combined through a bonding step, and finally folded to form a device. The preparation process is cumbersome. However, the key to market competitiveness lies in the cost-effectiveness and scalable manufacturing capabilities of thermoelectric generators. Therefore, in order to meet actual needs, it is necessary to efficiently utilize the temperature difference of the heat source while being able to be integrated on a large scale and meet a certain level of wearable comfort. Summary of the invention

[0005] In view of the above situation, the main purpose of the present invention is to propose a wearable thermoelectric generator based on a flexible corrugated tellurium film and a preparation method to solve the above technical problems.

[0006] The present invention proposes a wearable thermoelectric generator based on a flexible corrugated tellurium film, comprising a p-type tellurium film and an n-type tellurium-based film, wherein the p-type tellurium film and the n-type tellurium-based film are both made of a single-layer tellurium film, and the p-type tellurium-based thermoelectric unit and the n-type tellurium-based thermoelectric unit are alternately arranged to form a p-type tellurium film and an n-type tellurium-based film; A flexible film having p-type tellurium-based thermoelectric units and n-type tellurium-based thermoelectric units arranged alternately is bent, folded and packaged to obtain a wavy tellurium-based film; The exposed end of the pn junction of the thermoelectric generator in the wavy tellurium-based film is placed at the hot end, and the other end is placed in the air, so that the carriers of the p-type semiconductor and the carriers of the n-type semiconductor migrate from the hot end to the cold end to generate a thermoelectric potential in a uniform direction; The thermoelectric units that generate thermoelectric potential are connected in series to obtain a wearable thermoelectric generator.

[0007] The present invention also proposes a method for preparing a wearable thermoelectric generator based on a flexible corrugated tellurium film, the method being used to prepare the wearable thermoelectric generator based on the flexible corrugated tellurium film as described above, the method comprising: dissolving tellurium nanowire powder and polyvinylidene fluoride powder in an N,N-dimethylformamide solution to obtain a solution, and stirring the solution to form a mixed solution; subjecting the mixed solution to ultrasonic treatment to obtain a treated solution; The treatment liquid is transferred onto a glass sheet, and the glass sheet is placed on a heating plate for drying to obtain a dried p-type tellurium thin film; Using a single-sided polyimide tape as a substrate, the dried p-type tellurium film is transferred from a glass sheet to the polyimide tape to obtain a flexible, undoped p-type tellurium film with the polyimide tape as a substrate; The single-sidedly adhered polyimide tape is adhered to the p-type tellurium thin film as a substrate to obtain a fully adhered hoof film; Silver nitrate and ethylene glycol are uniformly mixed to obtain a solution of silver nitrate and ethylene glycol uniformly mixed, the hoof membrane that has been attached is immersed in the solution of silver nitrate and ethylene glycol uniformly mixed to perform in-situ reaction doping modification, and the membrane is left to stand overnight to obtain a silver-doped film; After sufficient reaction, the silver-doped film is taken out and rinsed to remove excess raw materials and by-products on the surface of the film to obtain a cleaned film; The cleaned film is dried to obtain a flexible film having p-type and n-type tellurium-based thermoelectric units arranged alternately; The flexible film having p-type tellurium-based thermoelectric units and n-type tellurium-based thermoelectric units arranged alternately is bent, folded and packaged to obtain a wavy tellurium-based film; The exposed end of the pn junction of the thermoelectric generator in the wavy tellurium-based film is placed at the hot end, and the other end is placed in the air, so that the carriers of the p-type semiconductor and the carriers of the n-type semiconductor migrate from the hot end to the cold end to generate a thermoelectric potential in a uniform direction; The thermoelectric units that generate thermoelectric potential are connected in series to obtain a wearable thermoelectric generator.

[0008] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention can generate thermoelectric potential in different common heat sources in life, such as human wrist, hot water cup or computer radiator, etc., and when the device is placed on the surface of the heat source, the higher the temperature difference between the hot and cold ends of the device, the greater the thermoelectric potential generated.

[0009] 2. The present invention has low preparation cost and simple preparation process and can be used for large-scale manufacturing. The p-type tellurium film is prepared by low-cost solvent thermal method and drop casting method. By cleverly using a single-sided adhesive polyimide tape, the conversion of alternating arrangement of p-type and n-type tellurium-based thermoelectric units can be achieved on a single-layer flexible p-type tellurium film. The thermoelectric power factor (PF=S 2 σ, S is the Seebeck coefficient, σ is the conductivity) can reach 19.07 μW m -1 K -2 and 25.99 μW m -1 K -2 .

[0010] 3. The thermoelectric generator of the present invention has a three-dimensional wavy structure configuration, which can effectively utilize the temperature difference perpendicular to the heat source surface. The designed wavy structure TEG with three pn pairs (TEG-3pn) achieves an open circuit voltage output of 50.46 mV at a temperature difference of 60 K. In addition, the scalability of the design is achieved by utilizing the characteristics of the wavy structure, and the output performance can be further improved by adjusting the geometric parameters of the device (such as height and area). At the same time, the configuration of the wavy structure and the encapsulation of polydimethylsiloxane achieve an ultra-high stretchability of 300% for the device.

[0011] 4. The present invention is low-cost, simple and easy to reproduce, and the materials used are replaceable.

[0012] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description or learned through embodiments of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 A schematic diagram of a thermoelectric generator of the present invention worn on a human wrist; Figure 2 The schematic diagram of the process of preparing p-type tellurium thin film by the solvothermal method and drop casting method of the present invention; Figure 3 A schematic diagram of the process of preparing a silver-doped thin film having p-type and n-type tellurium-based thermoelectric units alternately arranged by the in-situ reaction method of the present invention; Figure 4 A schematic diagram of the process of realizing a wearable thermoelectric generator with high stretchability by using bending, folding and packaging technology in the present invention; Figure 5 The thermoelectric performance diagram of the p-type and n-type tellurium-based thin films of the present invention; Figure 6 The voltage-current-power curve of the wavy structure TEG-3pn under different ΔT of the present invention; Figure 7 The open circuit voltage and output power diagram of the wavy structure TEG-3pn under different ΔT of the present invention; Figure 8 This is a graph showing the relationship between the open circuit voltage of the wavy structure TEG of the present invention and the number of pn pairs connected in series; Fig. 9 This is a graph showing the relationship between the voltage of the TEG and the height of the device under different ΔT of the present invention; Fig.10 The diagram is a relationship diagram of the voltage of the TEG under different ΔTs as the device area changes; Fig.11 The relative resistance and relative voltage changes of the TEG of the present invention when the bending radius r=15 mm is bent for 1000 times; Fig.12 The relative resistance and relative voltage changes of the TEG of the present invention after 1000 stretching cycles when the tensile strength is 80%; Fig.13 The relative resistance of the TEG of the present invention changes with tensile strain; Fig.14 This is a physical demonstration diagram of the wavy structure TEG of the present invention being stretched to 300%; Fig.15 The output voltage diagram of the TEG-4pn of the present invention when sitting and walking, wherein the illustration is the stable voltage output diagram when the TEG-4pn is worn on the human wrist; Fig.16 The output voltage diagram of the TEG-8pn of the present invention when sitting and walking, wherein the illustration is the stable voltage output diagram when the TEG-8pn is worn on the human wrist; Fig.17 The output voltages of the TEG-4pn and TEG-8pn of the present invention when placed on a hot water cup at 70°C. DETAILED DESCRIPTION

[0014] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0015] These and other aspects of the embodiments of the present invention will be apparent with reference to the following description and accompanying drawings. In these descriptions and accompanying drawings, some specific implementations of the embodiments of the present invention are specifically disclosed to represent some ways of implementing the principles of the embodiments of the present invention, but it should be understood that the scope of the embodiments of the present invention is not limited thereto.

[0016] Example 1 This embodiment proposes a wearable thermoelectric generator based on a flexible corrugated tellurium film, comprising a p-type tellurium film and an n-type tellurium-based film, wherein the p-type tellurium film and the n-type tellurium-based film are both made of a single-layer tellurium film, and the p-type tellurium-based thermoelectric unit and the n-type tellurium-based thermoelectric unit are alternately arranged to form a p-type tellurium film and an n-type tellurium-based film; The flexible film having p-type tellurium-based thermoelectric units and n-type tellurium-based thermoelectric units arranged alternately is bent, folded and packaged to obtain a wavy tellurium-based film; The exposed end of the pn junction of the thermoelectric generator in the wavy tellurium-based film is placed at the hot end, and the other end is placed in the air, so that the carriers of the p-type semiconductor and the carriers of the n-type semiconductor migrate from the hot end to the cold end to generate a thermoelectric potential in a uniform direction; The thermoelectric units that generate thermoelectric potential are connected in series to obtain a wearable thermoelectric generator.

[0017] Example 2 See also Figure 2 This embodiment provides a preparation process of a p-type thin film based on the embodiment 1. In this embodiment, a solvothermal method and a drop casting method are used to prepare the p-type thin film. In this embodiment, the method of preparing tellurium nanowire powder by the solvothermal method includes method 1, method 2, method 3 or method 4; The specific steps of method one are as follows: 1.5 g of sodium tellurite and 7.5 g of ascorbic acid powder were mixed in 120 mL of ethylene glycol solution and stirred for 0.3 h. After the solute was completely dissolved, a mixed solution was obtained. The mixed solution was transferred to a polytetrafluoroethylene autoclave at 90 ° C at a speed of 450 rpm and stirred for reaction for 20 h. After the reaction is complete, the reaction product is obtained, cooled to room temperature, and centrifuged and washed three times in a centrifuge at 5000 rpm, each time for 5 minutes, to remove by-products and excess raw materials, and ultrasonically cleaned for 4 minutes after the centrifugation; After ultrasonic cleaning, clean tellurium powder is obtained, and the clean tellurium powder is placed in a 60° C. oven and baked for 12 h to obtain tellurium nanowire powder.

[0018] The specific steps of method 2 are as follows: Dissolve 1 g of ascorbic acid and 0.1 g of hexadecyltrimethylammonium bromide in 40 ml of distilled water to obtain a clear solution; 0.052 g of sodium tellurite powder was added to the solution, and the mixture was stirred vigorously for 0.2 h to form a white suspension, and the suspension was heated to 90° C. for 20 h to obtain a reaction mixture; After the reaction mixture was cooled to room temperature, 50 ml of ethanol was added to the reaction mixture for precipitation to obtain tellurium nanowires; The tellurium nanowires were centrifuged at 5000 rpm for 4 min to recover the precipitate, and washed with distilled water and anhydrous ethanol to remove by-products and excess hexadecyltrimethylammonium bromide to obtain washed tellurium nanowire powder, and the washed tellurium nanowire powder was placed in a 50° C. vacuum drying oven for 10 h to obtain tellurium nanowire powder.

[0019] It should be noted that ascorbic acid is a reducing agent, sodium tellurite is a tellurium source, and hexadecyltrimethylammonium bromide is an anionic surfactant.

[0020] The specific steps of method three are as follows: Dissolve 3 mmol of sodium tellurite in 30 ml of ethylene glycol and stir vigorously at 120°C to obtain a colorless solution. 0.3 g of sodium borohydride was dissolved in 30 ml of ethylene glycol to obtain a solution, and the solution was added dropwise to the colorless solution of sodium tellurite to obtain a mixture; The mixture was refluxed at 280°C for 19 h to obtain tellurium nanorods; The tellurium nanorods were precipitated with isopropanol to obtain a precipitate, which was centrifuged at 5000 rpm for 4 minutes to collect the precipitate, and then washed with acetone to obtain a clean tellurium powder; The washed tellurium powder was placed in a 50°C oven and baked for 11 hours to obtain tellurium nanowire powder.

[0021] The specific steps of method 4 are as follows: Dissolve 0.1884 g of sodium tellurite and 0.942 g of polyvinyl pyrrolidone in 66 ml of deionized water and obtain a uniform solution under strong magnetic stirring at room temperature; Add 3.3 ml of hydrazine hydrate and 6.7 ml of aqueous ammonia to the homogeneous solution and stir to obtain a stirred solution; The stirred solution was poured into a sealed reactor and reacted at 170 °C for 3 h; After the reaction is complete, a reaction product is obtained, the reaction product is cooled to room temperature, and centrifuged for 6 minutes using a 5000 rpm centrifuge to recover the precipitate to obtain a recovered precipitate, the recovered precipitate is washed three times with deionized water and ethanol to remove by-products and excess raw materials, and after centrifugation, ultrasonic cleaning is performed for 4 minutes to obtain a washed tellurium powder; The washed tellurium powder was placed in a 50°C oven and baked for 11 hours to obtain tellurium nanowire powder.

[0022] Example 3 See also Figure 2 This embodiment provides a preparation process of a p-type thin film based on the embodiment 1. In this embodiment, a solvothermal method and a drop casting method are used to prepare the p-type thin film. In this embodiment, the method of preparing tellurium nanowire powder by the solvothermal method includes method 1, method 2, method 3 or method 4; The specific steps of method one are as follows: 1.75 g of sodium tellurite and 8.5 g of ascorbic acid powder were mixed in 160 mL of ethylene glycol solution and stirred for 0.5 h. After the solute was completely dissolved, a mixed solution was obtained. The mixed solution was transferred to a polytetrafluoroethylene autoclave at 95 ° C at a speed of 475 rpm and stirred for reaction for 22 h. After the reaction is complete, the reaction product is obtained, cooled to room temperature, and centrifuged and washed three times in a centrifuge at 6000 rpm, each time for 5 minutes, to remove by-products and excess raw materials, and ultrasonically cleaned for 6 minutes after the centrifugation; After ultrasonic cleaning, clean tellurium powder was obtained, and the clean tellurium powder was placed in a 60° C. oven and baked for 11 h to obtain tellurium nanowire powder, which was recorded as A1.

[0023] The specific steps of method 2 are as follows: Dissolve 5.5 g of ascorbic acid and 0.63 g of hexadecyltrimethylammonium bromide in 200 ml of distilled water to obtain a clear solution; 0.32 g of sodium tellurite powder was added to the solution, and the mixture was stirred vigorously for 0.4 h to form a white suspension, and the suspension was heated to 95° C. for 22 h to obtain a reaction mixture; After the reaction mixture was cooled to room temperature, 125 ml of ethanol was added to the reaction mixture for precipitation to obtain tellurium nanowires; The tellurium nanowires were centrifuged at 6000 rpm for 5 min to recover the precipitate, and washed with distilled water and anhydrous ethanol to remove by-products and excess hexadecyltrimethylammonium bromide to obtain a clean tellurium nanowire powder. The clean tellurium nanowire powder was placed in a vacuum drying oven at 60° C. for 11 h to obtain a tellurium nanowire powder, which was recorded as A2.

[0024] The specific steps of method three are as follows: Dissolve 3.5 mmol of sodium tellurite in 45 ml of ethylene glycol and stir vigorously at 130°C to obtain a colorless solution. 0.45 g of sodium borohydride was dissolved in 30 ml of ethylene glycol to obtain a solution, and the solution was added dropwise to the colorless solution of sodium tellurite to obtain a mixture; The mixture was refluxed at 290°C for 20 h to obtain tellurium nanorods; The tellurium nanorods were precipitated with isopropanol to obtain a precipitate, which was collected by centrifugation at 6000 rpm for 5 min, and then washed with acetone to obtain a clean tellurium powder; The washed tellurium powder was placed in a 60°C oven and baked for 12 h to obtain tellurium nanowire powder, which was recorded as A3.

[0025] The specific steps of method 4 are as follows: Dissolve 0.55 g of sodium tellurite and 3 g of polyvinyl pyrrolidone in 180 ml of deionized water and obtain a uniform solution under strong magnetic stirring at room temperature; Add 9.5 ml of hydrazine hydrate and 22 ml of aqueous ammonia to the homogeneous solution and stir to obtain a stirred solution; The stirred solution was poured into a sealed reactor and reacted at 185 °C for 4 h; After the reaction is complete, a reaction product is obtained, the reaction product is cooled to room temperature, and centrifuged for 5 minutes using a 6000 rpm centrifuge to recover the precipitate to obtain a recovered precipitate, the recovered precipitate is washed three times with deionized water and ethanol to remove by-products and excess raw materials, and after centrifugation, ultrasonic cleaning is performed for 6 minutes to obtain a washed tellurium powder; The washed tellurium powder was placed in a 60°C oven and baked for 12 hours to obtain tellurium nanowire powder, which was recorded as A4.

[0026] Example 4 See also Figure 2 This embodiment provides a preparation process of a p-type thin film based on the embodiment 1. In this embodiment, a solvothermal method and a drop casting method are used to prepare the p-type thin film. In this embodiment, the method of preparing tellurium nanowire powder by the solvothermal method includes method 1, method 2, method 3 or method 4; The specific steps of method one are as follows: 2 g of sodium tellurite and 10 g of ascorbic acid powder were mixed in 200 mL of ethylene glycol solution and stirred for 0.8 h. After the solute was completely dissolved, a mixed solution was obtained. The mixed solution was transferred to a 100°C tetrafluoroethylene autoclave at a rate of 500 rpm and stirred for reaction for 24 h. After the reaction is complete, the reaction product is obtained, cooled to room temperature, and centrifuged and washed three times in a centrifuge at 7000 rpm, each time for 6 minutes, to remove by-products and excess raw materials, and then ultrasonically cleaned for 8 minutes; After ultrasonic cleaning, clean tellurium powder was obtained, and the clean tellurium powder was placed in a 70° C. oven and baked for 12 h to obtain tellurium nanowire powder, which was recorded as B1.

[0027] The specific steps of method 2 are as follows: Dissolve 10 g of ascorbic acid and 1 g of hexadecyltrimethylammonium bromide in 400 ml of distilled water to obtain a clear solution; 0.52 g of sodium tellurite powder was added to the solution, and the mixture was stirred vigorously for 0.5 h to form a white suspension, and the suspension was heated to 100° C. for 24 h to obtain a reaction mixture; After the reaction mixture was cooled to room temperature, 200 ml of ethanol was added to the reaction mixture for precipitation to obtain tellurium nanowires; The tellurium nanowires were centrifuged at 7000 rpm for 6 min to recover the precipitate, and washed with distilled water and anhydrous ethanol to remove by-products and excess hexadecyltrimethylammonium bromide to obtain a washed tellurium nanowire powder. The washed tellurium nanowire powder was placed in a vacuum drying oven at 70°C for 12 h to obtain a tellurium nanowire powder, which was recorded as B2.

[0028] The specific steps of method three are as follows: Dissolve 4 mmol of sodium tellurite in 60 ml of ethylene glycol and stir vigorously at 140°C to obtain a colorless solution. 0.6 g of sodium borohydride was dissolved in 40 ml of ethylene glycol to obtain a solution, and the solution was added dropwise to the colorless solution of sodium tellurite to obtain a mixture; The mixture was refluxed at 300 °C for 21 h to obtain tellurium nanorods; The tellurium nanorods were precipitated with isopropanol to obtain a precipitate, which was centrifuged at 7000 rpm for 6 min to collect the precipitate, and then washed with acetone to obtain a clean tellurium powder; The washed tellurium powder was placed in a 70°C oven and baked for 13 h to obtain tellurium nanowire powder, which was recorded as B3.

[0029] The specific steps of method 4 are as follows: Dissolve 0.942 g of sodium tellurite and 5 g of polyvinyl pyrrolidone in 330 ml of deionized water and obtain a uniform solution under strong magnetic stirring at room temperature; Add 16.5 ml of hydrazine hydrate and 33.5 ml of aqueous ammonia to the homogeneous solution and stir to obtain a stirred solution; The stirred solution was poured into a sealed reactor and reacted at 190 °C for 5 h; After the reaction is complete, a reaction product is obtained, the reaction product is cooled to room temperature, and centrifuged for 6 minutes using a 7000 rpm centrifuge to recover the precipitate to obtain a recovered precipitate, the recovered precipitate is washed three times with deionized water and ethanol to remove by-products and excess raw materials, and after the centrifugation is completed, ultrasonic cleaning is performed for 8 minutes to obtain a washed tellurium powder; The washed tellurium powder was placed in a 70°C oven and baked for 13 h to obtain tellurium nanowire powder, which was recorded as B4.

[0030] Example 5 See also Figure 3 This embodiment provides a preparation process of a p-type tellurium thin film based on the embodiment 1. In this embodiment, the p-type tellurium thin film is prepared by a solvothermal method and a drop casting method. The specific steps of preparing the p-type tellurium thin film by drop casting using the tellurium nanowire powder prepared in the embodiment 3 are as follows: 0.26 g of dried tellurium nanowire powder and 0.13 g of polyvinylidene fluoride powder were dissolved in 6 mL of N,N-dimethylformamide and stirred for 20 min to obtain a mixed solution; The mixed solution was placed in an ultrasonic cell disruptor at 18% power for 30 min of ultrasonic treatment with an ultrasonic interval of 1.6 s to obtain a treated solution; The treatment solution was transferred onto a glass sheet, and the glass sheet was placed on a hot plate at 60° C. and baked for 1 h to obtain a p-type tellurium thin film.

[0031] Example 6 This embodiment provides a preparation process of a p-type tellurium thin film based on the embodiment 1. In this embodiment, the p-type tellurium thin film is prepared by a solvothermal method and a drop casting method. The specific steps of the process of preparing the p-type tellurium thin film by the drop casting method using the tellurium nanowire powder prepared in the embodiment 4 are as follows: 0.39 g of dried tellurium nanowire powder and 0.195 g of polyvinylidene fluoride powder were dissolved in 9 mL of N,N-dimethylformamide and stirred for 30 min to obtain a mixed solution; The mixed solution was placed in an ultrasonic cell disruptor at 20% power for 35 min of ultrasonic treatment with an ultrasonic interval of 1.95 s to obtain a treated solution; The treatment solution was transferred to a glass sheet, and the glass sheet was placed on a hot plate at 70°C and baked for 1.3 h to obtain a p-type tellurium thin film.

[0032] Example 7 This embodiment provides a preparation process of a p-type tellurium thin film based on the embodiment 1. In this embodiment, the p-type tellurium thin film is prepared by a solvothermal method and a drop casting method. The specific steps of preparing the p-type tellurium thin film by drop casting using the tellurium nanowire powder prepared in the embodiment 5 are as follows: 0.52 g of dried tellurium nanowire powder and 0.26 g of polyvinylidene fluoride powder were dissolved in 12 mL of N,N-dimethylformamide and stirred for 40 min to obtain a mixed solution; The mixed solution was placed in an ultrasonic cell disruptor at 22% power for 40 min of ultrasonic treatment with an ultrasonic interval of 2.3 s to obtain a treated solution; The treatment solution was transferred to a glass sheet, and the glass sheet was placed on a hot plate at 80°C and baked for 1.6 h to obtain a p-type tellurium thin film.

[0033] Example 8 See also Figure 3 This embodiment provides a preparation process of an n-type tellurium-based thin film on the basis of Embodiment 1, thereby realizing a flexible tellurium-based thin film with p-type tellurium-based thermoelectric units and n-type tellurium-based thermoelectric units arranged alternately on a single-layer p-type tellurium thin film; in this embodiment, an in-situ reaction method is used to prepare an n-type tellurium-based thin film, and the specific steps of the process of preparing an n-type tellurium-based thin film with p-type tellurium-based thermoelectric units and n-type tellurium-based thermoelectric units arranged alternately on a single-layer p-type tellurium thin film are as follows: The surface size of the single-sided adhesive is 25×75 mm 2 The polyimide tape is used as a substrate, and the dried tellurium film is transferred from the glass sheet to the polyimide tape to obtain a flexible p-type tellurium film with the undoped polyimide tape as a substrate; The single-sided adhesive surface size is 25×10 mm 2 The polyimide tape has a plane size of 25×75 mm 2 The p-type tellurium film as a substrate is adhered at equal intervals to obtain a fully adhered hoof film; It should be noted that the plane size here is 25×10 mm 2 The function of the polyimide tape is to protect the surface of the adhered tellurium film from being corroded by dopants; 30 mL of 0.1 mol / L silver nitrate and 60 mL of 98% ethylene glycol were uniformly mixed to obtain a solution of silver nitrate and ethylene glycol uniformly mixed; the hoof membrane that had been attached was immersed in the solution of silver nitrate and ethylene glycol uniformly mixed to perform in-situ reaction doping modification, and the solution was allowed to stand for 12 hours to obtain a silver-doped film; It should be noted that the volume ratio of silver nitrate to ethylene glycol is 2:1.

[0034] After sufficient reaction, the film was taken out and ethanol was used to wash the film in a cycle for 15 minutes by an ultrasonic machine. The number of cycles was three to remove excess raw materials and by-products on the surface of the film to obtain a cleaned film. The cleaned film was placed in a vacuum drying oven at 55° C. and dried for 1 h to obtain a flexible tellurium-based film having p-type tellurium-based thermoelectric units and n-type tellurium-based thermoelectric units arranged alternately.

[0035] Example 9 See also Figure 1 and Figure 4 This embodiment provides a preparation process of a wearable thermoelectric generator based on the embodiment 1. In this embodiment, the bending, folding and packaging technology is used to prepare the wearable thermoelectric generator with high stretchability. The specific steps are as follows: Silver paste is applied to both ends of the thin film in which the p-type tellurium-based thermoelectric units and the n-type tellurium-based thermoelectric units are alternately arranged after drying, and silver wires are used as electrodes to obtain a thin film in which electrodes are connected to the p-type and n-type tellurium-based thermoelectric units alternately arranged; The polydimethylsiloxane main agent and the curing agent are completely mixed in a mass ratio of 10:1 to prepare a polydimethylsiloxane precursor; The film with electrodes connecting the p-type tellurium-based thermoelectric unit and the n-type tellurium-based thermoelectric unit is bent into a wavy structure along the pn junction. After the bending is completed, it is placed in a 3D printed mold, a polydimethylsiloxane precursor is poured into it, and then placed in an oven at 65°C for 4 hours to cure, thereby fixing the shape of the device and encapsulating it; The shape-fixed and encapsulated device is removed from the 3D printed mold to obtain a wearable wavy structure thermoelectric generator with high stretchability.

[0036] The heat source of the wearable thermoelectric generator is the human wrist, a hot water cup or a computer radiator.

[0037] In order to verify the effectiveness of the present invention, Example 8 uses a flexible film with alternating arrangement of p-type and n-type tellurium-based thermoelectric units on a single-layer tellurium film, wherein the p-type is an undoped tellurium film and the n-type is a silver-doped tellurium-based film, referred to as a tellurium-silver film. The thermoelectric properties of the p-type and n-type tellurium-based thermoelectric films were tested at room temperature. The results are as follows: Figure 5 As shown in Figure 2, it can be seen that the Seebeck coefficient of the p-type tellurium film reaches 334 μV K -1 However, due to the inherent Seebeck coefficient of the thermoelectric figure of merit, the strong coupling between electrical conductivity and thermal conductivity, the electrical conductivity of p-type tellurium thin film is relatively low. When the p-type tellurium thin film is transformed into a tellurium-silver thin film through an in-situ reaction (mainly the reaction generates silver telluride), its Seebeck coefficient changes from positive to negative (-106 μV K-1 ) was modified, and its conductivity was greatly improved. Finally, the power factors of p-type and n-type tellurium-based films reached 19.07 μW m -1 K -2 and 25.99 μW m -1 K -2 .

[0038] The present invention adopts Example 9, and uses a thin film with alternately arranged p-type (tellurium thin film) and n-type (tellurium-silver thin film) tellurium-based thermoelectric units as a substrate to prepare a wearable wavy structure thermoelectric generator (TEG), and characterizes the power generation performance of the TEG. The output characteristic measurement results are shown in Figure 6 and Figure 7 In the following, a TEG consisting of N pn pairs is denoted as TEG-Npn, and a TEG consisting of 3 pn pairs is denoted as TEG-3pn. Figure 6 The power generation characteristic curve of TEG-3pn is shown, depicting the temperature difference (ΔT) range between the upper and lower surfaces of the wavy structure TEG from 10 K to 60 K. It is obvious that both the output voltage and output power of the device are greatly enhanced with the increase of ΔT. Figure 7 The open circuit voltage ( ), and use the formula The output power is calculated, where the internal resistance ( ) was tested to be about 4.5 kΩ. It can be seen that the prepared wavy structure TEG-3pn has an open circuit voltage of 50.46 mV at a temperature difference of 60 K and a maximum output power of 140 nW. There is a linear correlation between the open circuit voltage and the temperature difference, and the output power changes quadratically with the increase in the temperature difference. In addition, the scalable integration of generators is crucial to increase the energy output of the device. Here, the simple device preparation process facilitates the scalable manufacturing of TEG. The open circuit voltage of TEG can be significantly increased with the increase in the number of pn pairs in series, especially when the temperature difference is high. See Figure 8 When the number of pn pairs in series is 5, the open circuit voltage value at a temperature difference of 60 K is further increased to 78.1 mV.

[0039] In addition, regulating the geometric parameters of the device is a simple method to improve the performance output of the thermoelectric generator, thereby further improving the scalability of the thermoelectric generator design of the present invention. By changing the height and area of ​​the device's wavy structure, the voltage change measurement results under different temperature differences are as follows: Fig. 9 and Fig.10 As shown in Figure 2, it can be seen that when the device area remains unchanged, the output voltage of TEG increases with the increase of device height, especially when the temperature difference is 60 K ( Fig. 9The reason for the significant change should be attributed to the internal resistance of the device and the actual temperature difference between the hot and cold ends of the device, which is determined by the thermoelectric characteristics and the geometric parameters of the thermoelectric unit. When the device height is constant, when the area of ​​the device is changed (the length of the thermoelectric unit is a variable), the output voltage of the TEG remains basically unchanged at the same temperature difference. This means that the voltage output of the TEG is only related to the temperature difference between the hot and cold ends of the device ( Fig.10 ).

[0040] In order to improve the comfort and flexibility between wearable electronic devices and human tissue, TEG also needs to have good flexibility and stretchability to adapt to complex movements (such as joint rotation) while minimizing the high thermal impedance or discomfort caused by the air gap between the wearable TEG and the skin. The curing and encapsulation of the device with polydimethylsiloxane improves the flexibility and comfort of the device. The fatigue resistance and stability of the TEG were verified by measuring the relative performance changes of the wavy structure TEG during bending and stretching. When the bending radius was 15 mm, the relative resistance change (ΔR / R0) and relative voltage change (ΔU / U0) of the TEG remained relatively stable when it underwent 1000 bending tests, and the change range was less than 6%, indicating that the designed wavy structure TEG has good reliability and fatigue resistance ( Fig.11 ). The tensile cycle shows that after the TEG of the present invention is repeated 1000 times under 80% strain, the ΔR / R0 and ΔU / U0 of the device remain relatively stable ( Fig.12 ). It is worth noting that the wavy structure TEG of the present invention can be easily stretched to more than 300% ( Fig.13 and Fig.14 ), showing ultra-high stretchability.

[0041] In order to verify the practical application potential of the present invention, the actual electrical output performance of TEG was tested under different wearing conditions. When the ambient temperature was 22°C, the maximum open circuit voltage measured by the multimeter was 9.5 mV when the TEG-4pn was directly worn. At the same time, the actual electrical output performance of the device is related to the wearer's motion state. When the wearer is sitting and walking, the maximum output voltage reaches 11.82 mV and 13.17 mV respectively ( Fig.15 In addition, in order to maximize the wearing comfort and output performance of the human body, the present invention uses the same length and width (25×128 mm 2 ) with alternating arrangement of p-type and n-type tellurium-based thermoelectric units, the width of the thermoelectric unit is shortened from 10 mm to 6 mm, and the number of pn pairs in series is increased from 4 to 8 (TEG-8pn). The results are shown in Fig.16As shown in the illustration, under the same ambient temperature, the maximum open circuit voltage of TEG-8pn measured by a multimeter is 12.5 mV, which is about 3 mV higher than that of TEG-4pn. Similarly, under the same environment, its maximum open circuit voltage when sitting and walking is about 4mV and 5mV higher than that of TEG-4pn ( Fig.16 ).

[0042] The present invention can also collect energy from household heat sources (such as hot water cups). TEG-4pn and TEG-8pn are installed on hot water cups at 70°C. The voltage test results are as follows: Fig.17 As shown. Obviously, compared with TEG-4pn, the maximum open circuit voltage of TEG-8pn under high temperature difference is significantly increased, reaching 90.7 mV. However, it should be noted that for TEG-8pn, its voltage also decays faster after rising to the maximum value. This is because the height of TEG-8pn is shorter. After about 20 s, the voltage of TEG-8pn reaches thermal equilibrium and tends to stabilize. In summary, the present invention can effectively collect thermal energy in various scenarios, demonstrating its great potential in the field of wearable electronic devices.

[0043] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0044] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A wearable thermoelectric generator based on a flexible corrugated tellurium film, characterized in that: It includes a p-type tellurium film and an n-type tellurium-based film, both of which are made of a single-layer tellurium film, and the p-type tellurium-based thermoelectric units and the n-type tellurium-based thermoelectric units are alternately arranged to form the p-type tellurium film and the n-type tellurium-based film; A flexible film having p-type tellurium-based thermoelectric units and n-type tellurium-based thermoelectric units arranged alternately is bent, folded and packaged to obtain a wavy tellurium-based film; The exposed end of the pn junction of the thermoelectric generator in the wavy tellurium-based film is placed at the hot end, and the other end is placed in the air, so that the carriers of the p-type semiconductor and the carriers of the n-type semiconductor migrate from the hot end to the cold end to generate a thermoelectric potential in a uniform direction; The thermoelectric units that generate thermoelectric potential are connected in series to obtain a wearable thermoelectric generator.

2. A method for preparing a wearable thermoelectric generator based on a flexible corrugated tellurium film, the method being used to prepare the wearable thermoelectric generator based on a flexible corrugated tellurium film according to claim 1, characterized in that: The method comprises: dissolving tellurium nanowire powder and polyvinylidene fluoride powder in an N,N-dimethylformamide solution to obtain a solution, and stirring the solution to form a mixed solution; subjecting the mixed solution to ultrasonic treatment to obtain a treated solution; The treatment liquid is transferred onto a glass sheet, and the glass sheet is placed on a heating plate for drying to obtain a dried p-type tellurium thin film; Using a single-sided polyimide tape as a substrate, the dried p-type tellurium film is transferred from a glass sheet to the polyimide tape to obtain a flexible, undoped p-type tellurium film with the polyimide tape as a substrate; The single-sidedly adhered polyimide tape is adhered to the p-type tellurium thin film as a substrate to obtain a fully adhered hoof film; Silver nitrate and ethylene glycol are uniformly mixed to obtain a solution of silver nitrate and ethylene glycol uniformly mixed, the hoof membrane that has been attached is immersed in the solution of silver nitrate and ethylene glycol uniformly mixed to perform in-situ reaction doping modification, and the membrane is left to stand overnight to obtain a silver-doped film; After sufficient reaction, the silver-doped film is taken out and rinsed to remove excess raw materials and by-products on the surface of the film to obtain a cleaned film; The cleaned film is dried to obtain a flexible film having p-type and n-type tellurium-based thermoelectric units arranged alternately; The flexible film having p-type tellurium-based thermoelectric units and n-type tellurium-based thermoelectric units arranged alternately is bent, folded and packaged to obtain a wavy tellurium-based film; The exposed end of the pn junction of the thermoelectric generator in the wavy tellurium-based film is placed at the hot end, and the other end is placed in the air, so that the carriers of the p-type semiconductor and the carriers of the n-type semiconductor migrate from the hot end to the cold end to generate a thermoelectric potential in a uniform direction; The thermoelectric units that generate thermoelectric potential are connected in series to obtain a wearable thermoelectric generator.

3. The method for preparing a wearable thermoelectric generator based on a flexible corrugated tellurium film according to claim 2, characterized in that: The tellurium nanowire powder is prepared by method one, method two, method three or method four; The specific steps of preparing tellurium nanowire powder using method 1 are as follows: Sodium tellurite and ascorbic acid powder are mixed in ethylene glycol solution and stirred to obtain a mixed solution after the solute is completely dissolved, and the mixed solution is transferred to a polytetrafluoroethylene high-pressure reactor for stirring and reaction; After the reaction is complete, a reaction product is obtained, the reaction product is cooled to room temperature, centrifuged in a centrifuge to recover the precipitate, washed three times with deionized water and ethanol to remove by-products and excess raw materials, and ultrasonically cleaned after centrifugation; After ultrasonic cleaning, clean tellurium powder is obtained, and the clean tellurium powder is placed in an oven for baking to obtain tellurium nanowire powder; The specific steps of preparing tellurium nanowire powder using method 2 are as follows: Dissolve ascorbic acid and cetyltrimethylammonium bromide in distilled water to obtain a clear solution; Sodium tellurite is added to the solution, and the mixture is stirred vigorously to form a white suspension, and the suspension is heated to react to obtain a reaction mixture; After the reaction mixture is cooled to room temperature, ethanol is added to the reaction mixture for precipitation to obtain tellurium nanowires; The tellurium nanowires are centrifuged in a centrifuge to recover the precipitate, and are washed with distilled water and anhydrous ethanol to remove byproducts and excess hexadecyltrimethylammonium bromide to obtain washed tellurium nanowire powder, and the washed tellurium nanowire powder is placed in a vacuum drying oven for drying to obtain tellurium nanowire powder; The specific steps of preparing tellurium nanowire powder using method three are as follows: Dissolve sodium tellurite in ethylene glycol and stir vigorously to obtain a colorless solution; Sodium borohydride is dissolved in ethylene glycol to obtain a solution, and the solution is added dropwise to a colorless solution of sodium tellurite to obtain a mixture; The mixture is refluxed to obtain tellurium nanorods; Using isopropanol to precipitate the tellurium nanorods to obtain a precipitate, and centrifuging the precipitate to collect the precipitate, and washing the collected precipitate with acetone to obtain a clean tellurium powder; The washed tellurium powder is placed in an oven and baked overnight to obtain tellurium nanowire powder; The specific steps of preparing tellurium nanowire powder using method 4 are as follows: Dissolve sodium tellurite and polyvinyl pyrrolidone in deionized water and obtain a uniform solution under strong magnetic stirring at room temperature; Adding hydrazine hydrate and aqueous ammonia to the homogeneous solution and stirring to obtain a stirred solution; The stirred solution is poured into a sealed reactor to carry out the reaction; After the reaction is complete, a reaction product is obtained, the reaction product is cooled to room temperature, and centrifuged using a centrifuge to recover the precipitate to obtain a recovered precipitate, the recovered precipitate is washed three times with deionized water and ethanol to remove by-products and excess raw materials, and ultrasonic cleaning is performed after centrifugation to obtain a washed tellurium powder; The washed tellurium powder is placed in an oven and baked overnight to obtain tellurium nanowire powder.

4. The method for preparing a wearable thermoelectric generator based on a flexible corrugated tellurium film according to claim 3, characterized in that: In the process of preparing tellurium nanowire powder by method 1, sodium tellurite is a tellurium source, ascorbic acid is a reducing agent, and ethylene glycol is a reaction solvent and a weak reducing agent; The masses of sodium tellurite and ascorbic acid powders are 1.5 g to 2.0 g and 7.5 g to 10 g, the volume of ethylene glycol is 120 mL to 200 mL, and the magnetic stirring time is 0.3 h to 0.8 h; The reaction temperature set in the polytetrafluoroethylene high-pressure reactor is 90°C to 100°C, the reaction time is 20h to 24h, and the stirring rate is 450rpm to 500rpm; The speed of the centrifuge is 5000 rpm to 7000 rpm, the centrifugation time is 4 min to 6 min, and the cleaning time in the ultrasonic cleaning machine is 4 min to 8 min; The oven temperature is set to 50℃~70℃, and the baking time is set to 10h~12h; In the process of preparing tellurium nanowire powder by method 2, ascorbic acid is a reducing agent, sodium tellurite is a tellurium source, and hexadecyltrimethylammonium bromide is an anionic surfactant; The mass of ascorbic acid is 1g to 10g, the mass of hexadecyltrimethylammonium bromide is 0.1g to 1g, the mass of sodium tellurite is 0.052g to 0.52g, the volume of distilled water is 40mL to 400mL, and the vigorous stirring time is 0.2h to 0.5h; The suspension heating temperature is 90°C to 100°C, and the reaction time is 20h to 24h; The volume of ethanol added for precipitation is 50 mL to 200 mL, the speed of the centrifuge is 5000 rpm to 7000 rpm, and the centrifugation time is 4 min to 6 min; The oven temperature is 50℃~70℃, and the baking time is 10h~12h; In the process of preparing tellurium nanowire powder by method 3, the molar mass of sodium tellurite is 3 mmol to 4 mmol, and the temperature at which sodium tellurite is dissolved in ethylene glycol and vigorously stirred is 120° C. to 140° C.; The mass of sodium borohydride is 0.3 g to 0.6 g, and the volume of ethylene glycol dissolved in ethylene glycol is 20 mL to 40 mL; The mixture is refluxed at a temperature of 280°C to 300°C, and the reflux time is 19h to 21h; The speed of the centrifuge is set to 5000 rpm to 7000 rpm, and the centrifugation time is 4 min to 6 min; The oven temperature is 50℃~70℃, and the baking time is 11h~13h; In the process of preparing tellurium nanowire powder by method 4, hydrazine hydrate is used as a reducing agent and polyvinyl pyrrolidone is used as a surfactant; The mass of sodium tellurite is 0.1884 g to 0.942 g, the mass of polyvinyl pyrrolidone is 1 g to 5 g, and the volume of deionized water is 66 mL to 330 mL; Add hydrazine hydrate and ammonia water to the homogeneous solution. The volume of hydrazine hydrate added is 3.3mL~16.5mL, and the volume of ammonia water added is 6.7mL~33.5mL; The stirred solution is poured into a sealed reactor, the reaction temperature is 170°C to 190°C, and the reaction time is 3h to 5h; The speed of the centrifuge is 5000 rpm to 7000 rpm, the centrifugation time is 4 min to 6 min, and the cleaning time in the ultrasonic cleaning machine is 4 min to 8 min; The oven temperature is 50℃~70℃, and the baking time is 11h~13h.

5. The method for preparing a wearable thermoelectric generator based on a flexible corrugated tellurium film according to claim 4, characterized in that: In the process of preparing the p-type tellurium thin film, the masses of tellurium powder and polyvinylidene fluoride are 0.26 g to 0.52 g and 0.13 g to 0.26 g, respectively, the volume of N,N-dimethylformamide is 6 mL to 12 mL, and the magnetic stirring time is 20 min to 40 min; The power of the ultrasonic cell pulverizer is 18% to 22%, the ultrasonic interval is 1.6s to 2.3s, and the ultrasonic time is 30min to 40min; The setting temperature of the heating plate is 60°C to 80°C, and the baking time is 1h to 1.6h.

6. The method for preparing a wearable thermoelectric generator based on a flexible corrugated tellurium film according to claim 5, characterized in that: In the process of using a single-sided polyimide tape as a substrate, the polyimide tape has the same size as the glass sheet, with a plane size of 25×75 mm. 2 ; The single-sided polyimide tape is adhered to the p-type tellurium film as a substrate at equal intervals. The plane size of the polyimide tape is 25×10 mm 2 ; In the process of preparing the p-type tellurium thin film, the volume ratio of the silver nitrate solution to the ethylene glycol solution is 2 to 5:1, the reaction temperature is room temperature, and the reaction time is 11 to 14 hours; The ultrasonic cleaning time is 10 min to 20 min, the set temperature of the vacuum drying oven is 50°C to 60°C, and the drying time is 1 h to 3 h.

7. The method for preparing a wearable thermoelectric generator based on a flexible corrugated tellurium film according to claim 6, characterized in that: The flexible film having p-type tellurium-based thermoelectric units and n-type tellurium-based thermoelectric units arranged alternately is bent, folded and packaged to obtain a wavy tellurium-based film, which specifically includes the following steps: Silver paste is applied to both ends of the thin film in which the p-type tellurium-based thermoelectric units and the n-type tellurium-based thermoelectric units are alternately arranged after drying, and silver wires are used as electrodes to obtain a thin film in which electrodes are connected to the p-type tellurium-based thermoelectric units and the n-type tellurium-based thermoelectric units are alternately arranged; The polydimethylsiloxane main agent and the curing agent are completely mixed in a mass ratio of 10:1 to prepare a polydimethylsiloxane precursor; The thin film in which electrodes are connected to alternately arranged p-type tellurium-based thermoelectric units and n-type tellurium-based thermoelectric units is bent into a wavy structure along the pn junction, and after the bending is completed, it is placed in a 3D printed mold, and a polydimethylsiloxane precursor is poured into the mold for shape fixing and encapsulation to obtain a shape-fixed and encapsulated device; The shape-fixed and encapsulated device is removed from the 3D printed mold to obtain a wearable wavy structure thermoelectric generator with high stretchability.

8. The method for preparing a wearable thermoelectric generator based on a flexible corrugated tellurium film according to claim 7, characterized in that: The heat source of the wearable thermoelectric generator is the human wrist, a hot water cup or a computer radiator.

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