Flexible stretchable terahertz device based on single-walled carbon nanotubes and preparation method

Abstract

The invention discloses a flexible stretchable terahertz device based on a single-walled carbon nanotube, which is composed of an upper part and a lower part, the upper layer is a single-walled carbon nanotube metasurface layer etched with a periodic unit structure, and the lower layer is a flexible substrate layer. The invention further discloses a preparation method of the flexible stretchable terahertz device based on the single-walled carbon nanotubes. The preparation method comprises the following steps: firstly, adding single-walled carbon nanotube powder into concentrated sulfuric acid, and stirring to obtain a mixed solution of carbon nanotubes and concentrated sulfuric acid; and standing the mixed solution, pouring out the concentrated sulfuric acid on the upper layer after the carbon nanotube powder is precipitated, diluting the residual solution with water, standing again, repeating the operation for 3-5 times, drying the residual solution to obtain the carbon nanotube powder subjected to acid treatment and the like, and finally etching the periodic unit structure on the carbon nanotube film on the upper layer by using laser. According to the invention, the problem that the same sensing device in the prior art cannot perform high-sensitivity detection on various substances is solved.

Description

Technical Field

[0001] This invention belongs to the field of terahertz metamaterial device technology, specifically relating to flexible and stretchable terahertz devices based on single-walled carbon nanotubes. This invention also relates to a method for preparing flexible and stretchable terahertz devices based on single-walled carbon nanotubes. Background Technology

[0002] Terahertz waves are electromagnetic waves with a frequency range of 0.1-10 THz. They possess advantages such as high penetration and low photon energy. Furthermore, the vibrational and rotational modes of many biochemical molecules are distributed within the terahertz band. These characteristics make terahertz waves widely used in sensing and detection. In practical detection, the size of many biomolecules does not match the wavelength of terahertz waves, resulting in very weak interactions between the analyte and the terahertz waves. To address this issue, researchers utilize metasurfaces to modulate the phase, amplitude, and polarization properties of terahertz waves, enhancing the interaction between terahertz waves and molecules. A metasurface is a two-dimensional metamaterial composed of periodically or aperiodically arranged subwavelength scattering structures. By designing different structures on the material surface, the intrinsic frequency of surface plasmon resonance can be adjusted, and the interaction between terahertz waves and matter can be enhanced using the surface plasmon resonance effect, thereby improving the sensitivity of terahertz spectroscopy. Traditional metasurfaces have fixed structures after fabrication and can only operate within a very narrow frequency range. However, different substances possess their own unique fingerprint spectra, requiring different operating frequencies for detection devices. This makes it difficult to achieve high-sensitivity measurements of multiple substances using the same device. To broaden the operating range of terahertz metasurfaces, methods for real-time modulation of terahertz waves are needed. Among existing methods, utilizing reconfigurable metasurfaces for active modulation of terahertz waves is highly feasible. This method primarily involves altering the metasurface's geometry, structure, and bending the substrate. Carbon nanotubes, a carbon material with a unique structure, exhibit excellent thermal and electrical conductivity, as well as outstanding electrochemical performance. Metasurfaces fabricated using carbon nanotubes can enhance the interaction between the analyte molecule and the terahertz wave. Furthermore, carbon nanotubes possess good tensile strength and flexibility, allowing for high-intensity stretching and bending. Metasurfaces fabricated using these properties can alter their periodic structure through stretching or bending, thereby changing the resonant frequency. During detection, the resonant frequency and amplitude of the terahertz wave can be rapidly changed through simple mechanical modulation, selectively enhancing the detection signal for the target chemical substance, eliminating interference from other substances, and achieving rapid and accurate detection. Summary of the Invention

[0003] The purpose of this invention is to provide a flexible and stretchable terahertz device based on single-walled carbon nanotubes, which solves the problem in the prior art that the same sensor device cannot perform high-sensitivity detection of multiple substances.

[0004] Another object of the present invention is to provide a method for fabricating flexible and stretchable terahertz devices based on single-walled carbon nanotubes.

[0005] The first technical solution adopted in this invention is a flexible and stretchable terahertz device based on single-walled carbon nanotubes, which consists of two parts: the upper layer is a single-walled carbon nanotube metasurface layer with etched periodic unit structures, and the lower layer is a flexible substrate layer.

[0006] The second technical solution adopted in this invention is a method for fabricating flexible and stretchable terahertz devices based on single-walled carbon nanotubes. The method involves preparing a single-walled carbon nanotube metasurface layer using a vacuum filtration method, specifically implemented according to the following steps: Step 1: Add single-walled carbon nanotube powder to concentrated sulfuric acid and stir to obtain a mixed solution of carbon nanotubes and concentrated sulfuric acid; Step 2: Let the mixed solution obtained in Step 1 stand and wait for the carbon nanotube powder to precipitate. Then pour off the upper layer of concentrated sulfuric acid. Dilute the remaining solution with water and let it stand again. Repeat this operation 3-5 times. Dry the remaining solution to obtain acid-treated carbon nanotube powder. Step 3: Dissolve the carbon nanotube powder obtained in Step 2 in deionized water, add a dispersant, and stir until homogeneous to obtain a carbon nanotube dispersion. Step 4: The carbon nanotube dispersion obtained in Step 3 is subjected to water bath sonication, tip sonication, and centrifugation in sequence, and the supernatant is then collected. Step 5: Dilute the supernatant obtained in step 4 at a ratio of 1:10, then perform vacuum filtration to obtain a carbon nanotube film, and then dry it. Step 6: Immerse the dried carbon nanotube film in acetone solution to remove the filter membrane, and then transfer the immersed carbon nanotube film onto a flexible substrate.

[0007] Step 7: Process the metasurface by using a laser to etch periodic unit structures on the upper carbon nanotube film. The invention is further characterized in that, In step 1, the mass fraction of single-walled carbon nanotube powder is 0.0015%-0.0025%, and the temperature for stirring the single-walled carbon nanotube powder in concentrated sulfuric acid is 70-100℃, and the stirring time is 60-90 minutes.

[0008] In step 2, the remaining solution is dried at a temperature of 150-200℃.

[0009] In step 3, the dispersant is sodium dodecyl sulfonate (SDS), the carbon nanotube solution concentration is 0.02-0.05 mg / ml, and the dispersant concentration is 1-2% wt. / vol.

[0010] In step 4, the water bath ultrasonic power is 600-700W, the water bath ultrasonic time is 10-30 minutes, the tip ultrasonic power is 500-700W, the tip ultrasonic time is 60-120 minutes, the centrifugation speed is 15000-20000rpm, and the centrifugation time is 1-2 hours.

[0011] In step 5, the carbon nanotube film is dried at 50-80℃.

[0012] In step 6, the concentration of the acetone solution is 75%-99%.

[0013] In step 6, the flexible substrate is made of polydimethylsiloxane or rubber flexible dielectric material, and the thickness of the flexible substrate is 15-30 μm.

[0014] In step 7, the periodic unit structure has a period Px of 140-160 μm along the x-axis and a period Py of 100-120 μm along the y-axis. The structure consists of two nested open rings with the same structural parameters: the ring radius r is 35-45 μm, the ring line width w is 4-6 μm, the center distance d between the two rings is 8-14 μm, the opening is located outside the nested rings, the distance g1 from the upper end of the opening to the center line is 1-6 μm, the distance g2 from the lower end of the opening to the center line is (g1+5) μm, and the opening size g1+g2 is 7-17 μm.

[0015] The beneficial effects of this invention are that the flexible and stretchable terahertz device based on single-walled carbon nanotubes and its preparation method are made of a single-walled carbon nanotube metasurface layer with good tensile strength and flexibility and a polydimethylsiloxane (PDMS) or rubber substrate layer. The resonant frequency of the device can be changed by stretching or bending the device, thereby realizing dynamic modulation of terahertz waves and solving the problem that the same sensor device cannot perform high-sensitivity detection of multiple substances. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the unit structure of the flexible and stretchable terahertz device based on single-walled carbon nanotubes of the present invention. Figure 2 This is a schematic diagram of the stretching of the flexible and stretchable terahertz device based on single-walled carbon nanotubes of the present invention. Figure 3 The terahertz transmission spectra of the flexible and stretchable terahertz device based on single-walled carbon nanotubes of the present invention under different stretching degrees. Figure 4 This is a schematic diagram of the bending of the flexible and stretchable terahertz device based on single-walled carbon nanotubes according to the present invention. Figure 5 The terahertz transmission spectra of the flexible and stretchable terahertz device based on single-walled carbon nanotubes of this invention under different degrees of bending are shown.

[0017] In the figure, 1. Single-walled carbon nanotube metasurface layer, 2. Flexible substrate. Detailed Implementation

[0018] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0019] This invention is based on a flexible and stretchable terahertz device using single-walled carbon nanotubes, combined with Figure 1 It consists of two parts: the upper layer is a single-walled carbon nanotube metasurface layer 1 with etched periodic unit structure, and the lower layer is a flexible substrate layer 2.

[0020] The single-walled carbon nanotube metasurface layer 1 was prepared by vacuum filtration, specifically according to the following steps: Step 1: Add single-walled carbon nanotube powder to concentrated sulfuric acid and stir to obtain a mixed solution of carbon nanotubes and concentrated sulfuric acid; In step 1, the mass fraction of single-walled carbon nanotube powder is 0.0015%-0.0025%, and the temperature for stirring the single-walled carbon nanotube powder in concentrated sulfuric acid is 70-100℃, and the stirring time is 60-90 minutes.

[0021] Step 2: Let the mixed solution obtained in Step 1 stand and wait for the carbon nanotube powder to precipitate. Then pour off the upper layer of concentrated sulfuric acid. Dilute the remaining solution with water and let it stand again. Repeat this operation 3-5 times. Dry the remaining solution to obtain acid-treated carbon nanotube powder. In step 2, the remaining solution is dried at a temperature of 150-200℃.

[0022] Step 3: Dissolve the carbon nanotube powder obtained in Step 2 in deionized water, add a dispersant, and stir until homogeneous to obtain a carbon nanotube dispersion. In step 3, the dispersant is sodium dodecyl sulfonate (SDS), the carbon nanotube solution concentration is 0.02-0.05 mg / ml, and the dispersant concentration is 1-2% wt. / vol.

[0023] Step 4: The carbon nanotube dispersion obtained in Step 3 is subjected to water bath sonication, tip sonication, and centrifugation in sequence, and the supernatant is then collected. In step 4, the water bath ultrasonic power is 600-700W, the water bath ultrasonic time is 10-30 minutes, the tip ultrasonic power is 500-700W, the tip ultrasonic time is 60-120 minutes, the centrifugation speed is 15000-20000rpm, and the centrifugation time is 1-2 hours.

[0024] Step 5: Dilute the supernatant obtained in step 4 at a ratio of 1:10, then perform vacuum filtration to obtain a carbon nanotube film, and then dry it. In step 5, the carbon nanotube film is dried at 50-80℃.

[0025] Step 6: Immerse the dried carbon nanotube film in acetone solution, remove the filter membrane, and then transfer the immersed carbon nanotube film onto the flexible substrate 2.

[0026] In step 6, the acetone solution concentration is 75%-99%. The flexible substrate 2 is made of polydimethylsiloxane (PDMS) or rubber flexible dielectric material, which has the characteristics of tear resistance, electrical insulation, low electrical loss and good ductility in the terahertz frequency range. The thickness of the flexible substrate 2 is 15-30μm.

[0027] Step 7: Process the metasurface by using a laser to etch periodic unit structures on the upper carbon nanotube film. In step 7, the periodic unit structure has a period Px of 140-160 μm along the x-axis and a period Py of 100-120 μm along the y-axis. The structure consists of two nested open rings with the same structural parameters: the ring radius r is 35-45 μm, the ring line width w is 4-6 μm, the center distance d between the two rings is 8-14 μm, the opening is located outside the nested rings, the distance g1 from the upper end of the opening to the center line is 1-6 μm, the distance g2 from the lower end of the opening to the center line is (g1+5) μm, and the opening size g1+g2 is 7-17 μm.

[0028] Example 1 This invention is based on a flexible and stretchable terahertz device using single-walled carbon nanotubes, combined with Figure 1 It consists of two parts: the upper layer is a single-walled carbon nanotube metasurface layer 1 with etched periodic unit structure, and the lower layer is a flexible substrate layer 2.

[0029] The single-walled carbon nanotube metasurface layer 1 was prepared by vacuum filtration, specifically according to the following steps: Step 1: Add single-walled carbon nanotube powder to concentrated sulfuric acid and stir to obtain a mixed solution of carbon nanotubes and concentrated sulfuric acid; Step 2: Let the mixed solution obtained in Step 1 stand and wait for the carbon nanotube powder to precipitate. Then pour off the upper layer of concentrated sulfuric acid. Dilute the remaining solution with water and let it stand again. Repeat this operation 3-5 times. Dry the remaining solution to obtain acid-treated carbon nanotube powder. Step 3: Dissolve the carbon nanotube powder obtained in Step 2 in deionized water, add a dispersant, and stir until homogeneous to obtain a carbon nanotube dispersion. Step 4: The carbon nanotube dispersion obtained in Step 3 is subjected to water bath sonication, tip sonication, and centrifugation in sequence, and the supernatant is then collected. Step 5: Dilute the supernatant obtained in step 4 at a ratio of 1:10, then perform vacuum filtration to obtain a carbon nanotube film, and then dry it. Step 6: Immerse the dried carbon nanotube film in acetone solution, remove the filter membrane, and then transfer the immersed carbon nanotube film onto the flexible substrate 2.

[0030] Step 7: Process the metasurface by using a laser to etch periodic unit structures on the upper carbon nanotube film.

[0031] Example 2 This invention is based on a flexible and stretchable terahertz device using single-walled carbon nanotubes, combined with Figure 1 It consists of two parts: the upper layer is a single-walled carbon nanotube metasurface layer 1 with etched periodic unit structure, and the lower layer is a flexible substrate layer 2.

[0032] The single-walled carbon nanotube metasurface layer 1 was prepared by vacuum filtration, specifically according to the following steps: Step 1: Add single-walled carbon nanotube powder to concentrated sulfuric acid and stir to obtain a mixed solution of carbon nanotubes and concentrated sulfuric acid; In step 1, the mass fraction of single-walled carbon nanotube powder is 0.0015%-0.0025%, and the temperature for stirring the single-walled carbon nanotube powder in concentrated sulfuric acid is 70-100℃, and the stirring time is 60-90 minutes.

[0033] Step 2: Let the mixed solution obtained in Step 1 stand and wait for the carbon nanotube powder to precipitate. Then pour off the upper layer of concentrated sulfuric acid. Dilute the remaining solution with water and let it stand again. Repeat this operation 3-5 times. Dry the remaining solution to obtain acid-treated carbon nanotube powder. In step 2, the remaining solution is dried at a temperature of 150-200℃.

[0034] Step 3: Dissolve the carbon nanotube powder obtained in Step 2 in deionized water, add a dispersant, and stir until homogeneous to obtain a carbon nanotube dispersion. Step 4: The carbon nanotube dispersion obtained in Step 3 is subjected to water bath sonication, tip sonication, and centrifugation in sequence, and the supernatant is then collected. Step 5: Dilute the supernatant obtained in step 4 at a ratio of 1:10, then perform vacuum filtration to obtain a carbon nanotube film, and then dry it. Step 6: Immerse the dried carbon nanotube film in acetone solution, remove the filter membrane, and then transfer the immersed carbon nanotube film onto the flexible substrate 2.

[0035] Step 7: Process the metasurface by using a laser to etch periodic unit structures on the upper carbon nanotube film.

[0036] Example 3 This invention is based on a flexible and stretchable terahertz device using single-walled carbon nanotubes, combined with Figure 1 It consists of two parts: the upper layer is a single-walled carbon nanotube metasurface layer 1 with etched periodic unit structure, and the lower layer is a flexible substrate layer 2.

[0037] The single-walled carbon nanotube metasurface layer 1 was prepared by vacuum filtration, specifically according to the following steps: Step 1: Add single-walled carbon nanotube powder to concentrated sulfuric acid and stir to obtain a mixed solution of carbon nanotubes and concentrated sulfuric acid; In step 1, the mass fraction of single-walled carbon nanotube powder is 0.0015%-0.0025%, and the temperature for stirring the single-walled carbon nanotube powder in concentrated sulfuric acid is 70-100℃, and the stirring time is 60-90 minutes.

[0038] Step 2: Let the mixed solution obtained in Step 1 stand and wait for the carbon nanotube powder to precipitate. Then pour off the upper layer of concentrated sulfuric acid. Dilute the remaining solution with water and let it stand again. Repeat this operation 3-5 times. Dry the remaining solution to obtain acid-treated carbon nanotube powder. In step 2, the remaining solution is dried at a temperature of 150-200℃.

[0039] Step 3: Dissolve the carbon nanotube powder obtained in Step 2 in deionized water, add a dispersant, and stir until homogeneous to obtain a carbon nanotube dispersion. In step 3, the dispersant is sodium dodecyl sulfonate (SDS), the carbon nanotube solution concentration is 0.02-0.05 mg / ml, and the dispersant concentration is 1-2% wt. / vol.

[0040] Step 4: The carbon nanotube dispersion obtained in Step 3 is subjected to water bath sonication, tip sonication, and centrifugation in sequence, and the supernatant is then collected. In step 4, the water bath ultrasonic power is 600-700W, the water bath ultrasonic time is 10-30 minutes, the tip ultrasonic power is 500-700W, the tip ultrasonic time is 60-120 minutes, the centrifugation speed is 15000-20000rpm, and the centrifugation time is 1-2 hours.

[0041] Step 5: Dilute the supernatant obtained in step 4 at a ratio of 1:10, then perform vacuum filtration to obtain a carbon nanotube film, and then dry it. Step 6: Immerse the dried carbon nanotube film in acetone solution, remove the filter membrane, and then transfer the immersed carbon nanotube film onto the flexible substrate 2.

[0042] Step 7: Process the metasurface by using a laser to etch periodic unit structures on the upper carbon nanotube film.

[0043] Example 4 This invention is based on a flexible and stretchable terahertz device using single-walled carbon nanotubes, combined with Figure 1 It consists of two parts: the upper layer is a single-walled carbon nanotube metasurface layer 1 with etched periodic unit structure, and the lower layer is a flexible substrate layer 2.

[0044] The single-walled carbon nanotube metasurface layer 1 was prepared by vacuum filtration, specifically according to the following steps: Step 1: Add single-walled carbon nanotube powder to concentrated sulfuric acid and stir to obtain a mixed solution of carbon nanotubes and concentrated sulfuric acid; In step 1, the mass fraction of single-walled carbon nanotube powder is 0.0015%-0.0025%, and the temperature for stirring the single-walled carbon nanotube powder in concentrated sulfuric acid is 70-100℃, and the stirring time is 60-90 minutes.

[0045] Step 2: Let the mixed solution obtained in Step 1 stand and wait for the carbon nanotube powder to precipitate. Then pour off the upper layer of concentrated sulfuric acid. Dilute the remaining solution with water and let it stand again. Repeat this operation 3-5 times. Dry the remaining solution to obtain acid-treated carbon nanotube powder. In step 2, the remaining solution is dried at a temperature of 150-200℃.

[0046] Step 3: Dissolve the carbon nanotube powder obtained in Step 2 in deionized water, add a dispersant, and stir until homogeneous to obtain a carbon nanotube dispersion. In step 3, the dispersant is sodium dodecyl sulfonate (SDS), the carbon nanotube solution concentration is 0.02-0.05 mg / ml, and the dispersant concentration is 1-2% wt. / vol.

[0047] Step 4: The carbon nanotube dispersion obtained in Step 3 is subjected to water bath sonication, tip sonication, and centrifugation in sequence, and the supernatant is then collected. In step 4, the water bath ultrasonic power is 600-700W, the water bath ultrasonic time is 10-30 minutes, the tip ultrasonic power is 500-700W, the tip ultrasonic time is 60-120 minutes, the centrifugation speed is 15000-20000rpm, and the centrifugation time is 1-2 hours.

[0048] Step 5: Dilute the supernatant obtained in step 4 at a ratio of 1:10, then perform vacuum filtration to obtain a carbon nanotube film, and then dry it. In step 5, the carbon nanotube film is dried at 50-80℃.

[0049] Step 6: Immerse the dried carbon nanotube film in acetone solution, remove the filter membrane, and then transfer the immersed carbon nanotube film onto the flexible substrate 2.

[0050] In step 6, the acetone solution concentration is 75%-99%. The flexible substrate 2 is made of polydimethylsiloxane (PDMS) or rubber flexible dielectric material, which has the characteristics of tear resistance, electrical insulation, low electrical loss and good ductility in the terahertz frequency range. The thickness of the flexible substrate 2 is 15-30μm.

[0051] Step 7: Process the metasurface by using a laser to etch periodic unit structures on the upper carbon nanotube film. Example 5 The upper layer of the device of the present invention is a carbon nanotube metasurface layer with a periodic structure etched on it. The resonant frequency of the device is in the terahertz band. When it resonates with the terahertz wave, its electric field strength is mainly concentrated at the opening position of the two nested rings. When the size of the opening changes, its resonant frequency will also change. Therefore, the modulation of the terahertz wave can be achieved by changing the size of the opening position of the structure.

[0052] The flexible and stretchable terahertz device based on single-walled carbon nanotubes of this invention utilizes materials with good flexibility and tensile properties for both the upper metasurface layer and the lower substrate layer. When detecting different substances, the device can be stretched or bent as needed to change the structural parameters of the metasurface and adjust the phase and amplitude of the resonance frequency in the device's transmission spectrum. This allows the device's resonance frequency to better match the analyte, improving the accuracy of the detection. The flexible and stretchable terahertz device based on single-walled carbon nanotubes of the present invention can change the device structure by stretching or bending to achieve the control of terahertz waves. The implementation steps are as follows: Modulation of terahertz waves is achieved through stretching. As attached Figure 2 As shown, when stress is applied to the device along the y-axis, the unit structure of the upper metasurface deforms, the distance between the openings of the two elliptical rings increases, and the resonance weakens. (See attached image) Figure 3 This paper presents the terahertz transmission spectra of a flexible, stretchable terahertz device based on single-walled carbon nanotubes under different stretching degrees. Different stretching degrees alter the size of the device opening; therefore, g1 represents different stretching degrees. It can be seen that as the stretching degree increases, the resonant frequency near 1.25 THz undergoes a blue shift, and the resonance peak amplitude gradually decreases. Therefore, this method can be used to mechanically modulate the terahertz wave, thereby improving detection sensitivity.

[0053] Example 6 Modulation of terahertz waves is achieved by bending. like Figure 4 , Figure 5As shown, bending the device along the y-axis alters the unit structure of the upper metasurface as the degree of bending increases, enhancing resonance and further changing the device's transmission spectrum. Here, c (unit: cm⁻¹) is used. -1 The curvature (c) represents the curvature at different degrees of bending, and its relationship with the bending radius r is c = 1 / r. Figure 5 This figure shows the terahertz transmission spectra of the flexible, stretchable terahertz device based on single-walled carbon nanotubes under different degrees of bending. As can be seen from the figure, when the device is bent, the amplitude of the resonance peak near 1.2 THz increases continuously with the increase of the bending degree. The resonance frequency first redshifts, and then gradually blueshifts when the curvature exceeds 2.38. Therefore, this method can be used to modulate terahertz waves.

[0054] In summary, the flexible and stretchable terahertz device based on single-walled carbon nanotubes of this invention consists of a single-walled carbon nanotube metasurface layer and a flexible substrate. This device exhibits good flexibility and stretchability, and its resonant frequency and amplitude can be changed through simple stretching or bending, achieving mechanical modulation of terahertz waves. When detecting different biochemical molecules, the frequency parameters of the terahertz waves can be rapidly changed through mechanical modulation, enabling highly sensitive detection of a variety of substances.

Claims

1. A flexible and stretchable terahertz device based on single-walled carbon nanotubes, characterized in that, It consists of two parts: the upper layer is a single-walled carbon nanotube metasurface layer with etched periodic unit structure (1), and the lower layer is a flexible substrate layer (2).

2. A method for fabricating flexible and stretchable terahertz devices based on single-walled carbon nanotubes, characterized in that, The specific steps are as follows: Step 1: Add single-walled carbon nanotube powder to concentrated sulfuric acid and stir to obtain a mixed solution of carbon nanotubes and concentrated sulfuric acid; Step 2: Let the mixed solution stand, after precipitation, pour off the upper layer of concentrated sulfuric acid, dilute the remaining solution with water, let it stand again, and dry it to obtain acid-treated carbon nanotube powder. Step 3: Dissolve carbon nanotube powder in deionized water, add dispersant, and stir to obtain carbon nanotube dispersion; Step 4: The carbon nanotube dispersion is subjected to water bath sonication, tip sonication, and centrifugation in sequence, and the supernatant is collected. Step 5: Dilute the supernatant at a ratio of 1:10, then perform vacuum filtration to obtain a carbon nanotube film, and then dry it. Step 6: Immerse the dried carbon nanotube film in acetone solution, remove the filter membrane, and then transfer the immersed carbon nanotube film onto the flexible substrate (2). Step 7: Process the metasurface by using a laser to etch periodic unit structures on the upper carbon nanotube film.

3. The method for fabricating a flexible and stretchable terahertz device based on single-walled carbon nanotubes according to claim 2, characterized in that, In step 1, the mass fraction of the single-walled carbon nanotube powder is 0.0015%-0.0025%, and the temperature for stirring the single-walled carbon nanotube powder in concentrated sulfuric acid is 70-100℃, and the stirring time is 60-90 minutes.

4. The method for fabricating a flexible and stretchable terahertz device based on single-walled carbon nanotubes according to claim 3, characterized in that, In step 2, the remaining solution is dried at a temperature of 150-200°C.

5. The method for fabricating a flexible and stretchable terahertz device based on single-walled carbon nanotubes according to claim 4, characterized in that, In step 3, the dispersant is sodium dodecyl sulfonate (SDS), the carbon nanotube solution concentration is 0.02-0.05 mg / ml, and the dispersant concentration is 1-2% wt. / vol.

6. The method for fabricating a flexible and stretchable terahertz device based on single-walled carbon nanotubes according to claim 5, characterized in that, In step 4, the water bath ultrasonic power is 600-700W, the water bath ultrasonic time is 10-30 minutes, the tip ultrasonic power is 500-700W, the tip ultrasonic time is 60-120 minutes, the centrifugation speed is 15000-20000rpm, and the centrifugation time is 1-2 hours.

7. The method for fabricating a flexible and stretchable terahertz device based on single-walled carbon nanotubes according to claim 6, characterized in that, In step 5, the carbon nanotube film is dried at 50-80°C.

8. The method for fabricating a flexible and stretchable terahertz device based on single-walled carbon nanotubes according to claim 7, characterized in that, In step 6, the concentration of the acetone solution is 75%-99%.

9. The method for fabricating a flexible and stretchable terahertz device based on single-walled carbon nanotubes according to claim 8, characterized in that, In step 6, the flexible substrate (2) is made of polydimethylsiloxane or rubber flexible dielectric material, and the thickness of the flexible substrate (2) is 15-30 μm.

10. The method for fabricating a flexible and stretchable terahertz device based on single-walled carbon nanotubes according to claim 9, characterized in that, In step 7, the periodic unit structure has a period Px of 140-160 μm along the x-axis and a period Py of 100-120 μm along the y-axis. The structure consists of two nested open rings with identical structural parameters: a ring radius r of 35-45 μm, a ring line width w of 4-6 μm, a center-to-center distance d of 8-14 μm, and an opening located outside the nested rings. The distance g1 from the upper end of the opening to the center line is 1-6 μm, the distance g2 from the lower end of the opening to the center line is (g1+5) μm, and the opening size g1+g2 is 7-17 μm.

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