TWI793913B - Self-powered gas sensors with ag modified zno nanorods - Google Patents

Abstract

The present invention provides a self-powered gas sensors with Ag modified ZnO nanorods comprising an Ag modified lower electrode with an ITO substrate which formed a ZnO nanorods array on thereof, wherein, a surface of the ZnO nanorods array is sputtered with an Ag nano particle; and an upper electrode that comprises the ITO substrate which carved an electrode pattern on its surface, and a metal particle electrode is sputtered on the surface of the electrode pattern. Combined the Ag modified lower electrode and the upper electrode to form the Self-powered gas sensors.

Description

Silver-modified ZnO nanopillars for self-powered gas sensors

A self-powered gas sensor, in particular a self-powered gas sensor with silver-modified zinc oxide nanocolumns.

With the rise of environmental protection awareness and the rapid development of science and technology in recent years, a self-generating technology formed by combining photoelectric technology and semiconductor technology on the same chip has gradually become a trend. This self-generating technology can use a naturally occurring mechanical energy (such as: motion, percussion, vibration, flow, sound wave, etc.) into an electric energy, not only has the advantages of small size, light weight and low cost, but also can save the application of the external power supply, effectively achieve the purpose of environmental protection, and can overcome For example, solar cells cannot be charged at night and have low conversion efficiency.

In addition, in the field of semiconductor research, it is also provided that a metal oxide semiconductor can be modified by doping a noble metal nanoparticle (such as platinum, palladium, gold, silver, etc.) to improve the performance of the metal oxide semiconductor.

However, a gas sensor that is currently used in medicine to detect an asthma through the concentration of nitric oxide gas needs to be connected to an external power supply before it can be driven. If the self-generating technology can be applied to the gas sensor It is a very leading progress in self-generation and medical-related fields to achieve size reduction, auxiliary medical application, and improvement of convenience and application range at the same time.

In order to develop a technology capable of applying self-power generation to the gas sensor, the present invention provides a self-powered gas sensor of silver-modified zinc oxide nanocolumns, which includes a silver-modified lower electrode, and the silver-modified lower electrode Including an indium tin oxide polyester substrate and a zinc oxide nanocolumn array formed on the indium tin oxide polyester substrate from bottom to top, and a silver nanoparticle is sputtered on the surface of the zinc oxide nanocolumn array and an upper electrode, the upper electrode includes the indium tin oxide polyester substrate with an electrode pattern engraved on the surface from bottom to top, a metal particle electrode is sputtered on the surface of the electrode pattern, and the silver modified lower electrode and the upper electrode are mutually Correspondingly bonded, the self-powered gas sensor is formed.

Wherein, a mechanical force is given to the self-powered gas sensor, so that at least a part of the ZnO nanorod array is bent due to the vibration of the mechanical force, and when it is in contact with the upper electrode, according to the nitrogen monoxide flow environment generate a voltage.

Wherein, the ITO polyester substrate includes a substrate and an ITO film on the surface of the substrate from bottom to top, wherein the substrate is a flexible substrate.

Wherein, a radio frequency magnetron sputtering system is used to sputter the zinc oxide seed crystal layer on the surface of the indium tin oxide film.

Wherein, the zinc oxide seed layer has a thickness of 100 nm.

Further, the hot water method step includes: immersing the indium tin oxide polyester substrate sputtered with the zinc oxide seed layer in a culture solution, wherein the culture solution contains zinc mononitrate and hexamethylene and placing the indium tin oxide polyester substrate in the oven at 95° C. for 3 hours to form the zinc oxide nanocolumn array.

Further, a radio frequency sputtering system is used to sputter the silver nanoparticles on the surface of the zinc oxide nanocolumn array, wherein the sputtering conditions of the radio frequency sputtering system are: an argon gas and a flow rate of 20 milliliters per minute (sccm), a pressure value of 0.0075 Torr (Torr), an incident power of 50 watts (W), and a time of 20 seconds.

Further, the metal particle electrode is a silver particle electrode.

Further, the metal particle electrode is the silver particle electrode with a thickness of 100 nm.

The self-powered gas sensor of silver-modified zinc oxide nanocolumns provided by the present invention has the following advantages:

1. The ZnO nanopillar array 13 can be grown by hydrothermal method, which can be completed at low temperature. The simple manufacturing process not only has high success rate and quality, but also reduces pollution due to low overall cost.

2. By giving the mechanical force, the self-powered gas sensor of the silver-modified zinc oxide nanocolumn can convert a mechanical energy into an electrical energy output, realizing the nanoscale power generation function and achieving the effect of reducing the volume.

3. Through the combination of a self-generating system and a gas sensor, the silver nanoparticle modification is introduced on the surface of the zinc oxide nanopillar to improve the gas sensing ability of the nitric oxide.

The self-powered gas sensor of the silver-modified zinc oxide nanocolumn provided by the present invention has greatly improved the nitric oxide gas sensing ability and can not only be effectively used in medical treatment to detect an asthma disease through the concentration of nitric oxide gas , also because the self-powered gas sensor of silver-modified zinc oxide nanopillars has the effect of vibration power generation and volume reduction, it can also be modularized in the future as a portable instrument for measuring the concentration of nitric oxide gas exhaled by humans, Contribute to the practical application of clinical and research aspects of medicine.

The silver-modified zinc oxide nanocolumn self-powered gas sensor provided by the present invention can be further combined with an Internet of Things system because it has the ability of self-power generation. For example, in a medical application, the self-powered gas sensor of the silver-modified zinc oxide nanopillar is used for the measurement of nitric oxide gas. The self-powered gas sensor modified with ZnO nanopillars can send an abnormal signal to the IoT system, so that a corresponding medical team can receive the abnormal signal immediately to achieve better tracking and care functions.

As another example, when the self-powered gas sensor of the silver-modified zinc oxide nanocolumn is applied to a chemical industry, it can monitor whether a harmful gas in a chemical environment is leaked at any time, and utilizes the energy of self-power generation Lida sends out an emergency signal such as an instant ringing bell or flashing lights, and combines with the IoT system to respond to the emergency signal to the relevant units to achieve timely rescue and prevent major disasters.

10: Substrate

11: Indium tin oxide film

12: Zinc oxide seed layer

13: ZnO nanopillar array

131: ZnO nanopillars

14:Silver nanoparticles

15: Metal particle electrode

16: Sensing area

A: Silver modified lower electrode

B: Upper electrode

Fig. 1 is the step diagram of the preferred embodiment provided by the present invention

Fig. 2 is the three-dimensional schematic diagram of the preferred embodiment of the first part provided by the present invention

Figure 3A is a top view of the zinc oxide nanopillar array provided by the present invention

Figure 3B is a side view of the zinc oxide nanopillar array provided by the present invention

Figure 4A is a top view of the silver-modified zinc oxide nanopillar array provided by the present invention

Figure 4B is a side view of the silver-modified zinc oxide nanopillar array provided by the present invention

Fig. 5 is the X-ray diffraction analysis spectrum provided by the present invention

Fig. 6A is the non-annealed light-excited fluorescence spectrum provided by the present invention

Fig. 6B is an annealed photoexcited fluorescence spectrum provided by the present invention

Fig. 7 is the three-dimensional schematic view of the preferred embodiment of the second part provided by the present invention

Figure 8 is a perspective view of a preferred embodiment provided by the present invention

Please refer to FIG. 1 and FIG. 2, which are the self-powered gas sensor manufacturing method of the silver-modified zinc oxide nanocolumn provided by the present invention. The steps include: step S1, prepare a substrate 10: first immerse the substrate 10 In an acetone (Acetone) solution, and in an ultrasonic shock washing machine for 10 minutes, remove an oil and an impurity on the surface of the substrate 10, improve the adhesion of the substrate 10, and prevent it from affecting the subsequent process. Growth efficiency and quality of a nanopillar.

After the substrate 10 is shaken by the acetone (Acetone) solution, the substrate 10 is immersed in an isopropyl alcohol (Isopropyl Alcohol) solution, and shaken in the ultrasonic shaker for 10 minutes to remove the acetone (Acetone) and The remaining oil and impurities.

After the substrate 10 is shaken by the isopropyl alcohol (Isopropyl Alcohol) solution, the substrate 10 is immersed in a deionized water (De-ionized water), and shaken for 10 minutes in an ultrasonic shock washer to remove the isopropyl alcohol. Propanol (Isopropyl Alcohol) solution.

Then, the surface of the substrate 10 is blown dry in a drying procedure. In this embodiment, a nitrogen gun is used to blow the surface of the substrate 10, and in this procedure, it can be observed whether the substrate 10 still has the oil or impurities. If the substrate 10 has not been cleaned completely, the acetone can be reused (Acetone) solution, the isopropyl alcohol (Isopropyl Alcohol) and the deionized water (De-ionized water) shock washing procedure. Finally, put the substrate 10 after confirming that the oil quality or the impurity has been removed, into an oven at 65° C. to dry the remaining moisture.

Wherein, the substrate 10 is a flexible substrate that is light, thin, flexible and can effectively save space. In terms of manufacturing process, the selection of the flexible substrate can achieve the effect of low cost and high production capacity by using the continuous production method (Roll to Roll). Further, the material of the substrate 10 can be a polyester (Polyester, PET) substrate or a polyimide (Polyimide, PI) substrate. In this embodiment, the substrate 10 is coated with an indium oxide on one side. Tin (ITO) film 11 on an indium tin oxide polyester (ITO-PET) substrate.

Step S2, making a silver-modified lower electrode A: using a radio frequency magnetron sputtering system to sputter a zinc oxide seed layer 12 on the substrate 10 and on the surface of the indium tin oxide (ITO) film 11, wherein the The zinc oxide seed layer 12 has a thickness of 100 nm. Using the radio frequency magnetron sputtering system can achieve fast sputtering rate and relatively uniform formation of the zinc oxide seed layer, improving overall precision and adhesion of the zinc oxide seed layer.

Using a hot water method, the substrate 10 sputtered with the zinc oxide seed layer 12 is soaked in a culture solution, wherein the culture solution contains zinc nitrate and hexamethylenetetramine. In this embodiment , The ratio of the zinc nitrate and the hexamethylenetetramine is 2:1. Then place the substrate 10 soaked in the culture solution in the oven at 95° C. for 3 hours, so that a plurality of zinc oxide nanopillars 131 grow on the zinc oxide seed layer 12 to form a zinc oxide nanopillar array 13. The hydrothermal method has the characteristics of low temperature, convenience, simple manufacturing process, and good product quality, and the zinc oxide nanopillars 131 grown by the hydrothermal method can achieve the advantage of scaling up.

Next, after the growth of the zinc oxide nanopillar array 13 is completed, a silver nanoparticle 14 is sputtered on the surface of each zinc oxide nanopillar 131 by using the radio frequency sputtering system to form a silver-modified zinc oxide nanopillar array , and complete the silver-modified lower electrode A. Wherein, the RF sputtering system utilizes an argon gas with a gas flow rate of 20 ml/min (sccm), a pressure value of 0.0075 Torr (Torr), an incident power of 50 watts (W) and a time of 20 seconds to sputter the Silver nanoparticles14.

Please refer to FIG. 3A to FIG. 7B , the present invention further uses a field-emission scanning electron microscope (Field-Emission Scanning Electron Microscope, FE-SEM), a penetration Electron Microscope (TEM), X-ray Diffraction (X-Ray Diffraction, XRD), and Photoluminescence-PL (Photoluminescence-PL) are used to measure surface optics and surface structure.

In the present invention, the field emission scanning electron microscope (JEOLJSM-7800F) is used to analyze the structure, film thickness and surface morphology of the silver nanoparticles 14 modifying the ZnO nanopillars 131 . The principle of the field emission scanning electron microscope is to use an electron gun to generate a high-energy electron beam through the principle of thermal ionization or field emission, and focus the high-energy electron beam on the silver-modified lower electrode A. At this time, the silver-modified lower electrode The electrons on the surface of A will be released by the impact of the high-energy electron beam, which are called secondary electrons. Then, the field emission scanning electron microscope uses a scanning coil to deflect the electron beam, scans on the surface of the silver-modified lower electrode A, detects an electronic signal of the secondary electron, and amplifies it through an amplifier to analyze the secondary electron signal. A state of sub-electrons forms an electron image with a material surface, a substance type and a potential.

Among them, Figure 3A is a top view of the zinc oxide nanopillar array after growing at 95°C for 3 hours, and Figure 3B is a side view of the zinc oxide nanopillar array; Figure 4A is growing at 95°C for 3 hours A top view of a silver-modified ZnO nanocolumn array followed by sputtering of the silver nanoparticles 14 on the surface, and FIG. 4B is a side view of the silver-modified ZnO nanocolumn array.

The morphology of the ZnO nanocolumns modified by the silver nanoparticles 14 can be studied through the field emission scanning electron microscope. After comparing Fig. 3A and Fig. 3B with Fig. 4A and Fig. 4B, it can be clearly observed that each of the zinc oxide nanopillars has an asymmetric hexagonal structure and the growth direction is perpendicular to the growth of the substrate 10, and through the The modification of the silver nanoparticles 14 will not affect the overall diameter and height of the ZnO nanopillars. Further observing the enlarged view in the upper right corner of FIG. 4A, it can be observed that each of the zinc oxide nanopillars 131 is attached with a plurality of the silver nanoparticles 14, and it can be confirmed that the silver nanoparticles 14 are successfully sputtered on each of the zinc oxide nanopillars. ZnO nanopillars 131 on the surface.

As shown in Figure 5, the present invention detects the crystal structure of the silver-modified lower electrode A in a non-destructive manner through the X-ray diffraction analyzer, measures the intensity of a diffraction peak of the silver-modified lower electrode A and corresponds to a A diffraction pattern (Diffraction Pattern) is obtained by plotting the radiation angle. By comparing the diffraction pattern with a JCPDS database, it can be judged whether the intensity of each diffraction peak conforms to the structure of the zinc oxide nanocolumn 131 . Figure 5 shows the ZnO nanocolumn diffraction pattern (Pure) of the ZnO nanocolumn array 13 located below and a silver modified ZnO diffraction pattern of the silver modified ZnO nanocolumn array located above. Nanopillar pattern (Ag). It can be seen that the ZnO nanopillar diffraction pattern (Pure) and the silver-modified ZnO diffraction nanopillar pattern (Ag) both have peaks of 002, 102, and 103, of which the 002 peak (34.552°) can correspond to To the diffraction peak intensity of ZnO nanocolumnar structures in the JCPDS database. Also because the height of the 002 (34.552°) peak is significantly higher than the other two peaks, it means that both the ZnO nanopillar array 13 and the silver-modified ZnO nanopillar array grow in a direction perpendicular to the substrate 10 .

As shown in Figures 6A and 6B, in the present invention, a light-excited fluorescence spectrometer whose model is He-Cd Laser, CW325nm, Max200Mw is used to analyze the silver nanoparticles 14 modified zinc oxide nanocolumns 131 structure. The light-excited fluorescence spectrometer uses a helium-cadmium laser light to hit the silver-modified lower electrode A. When the energy of the helium-cadmium laser light is higher than a surface material of the silver-modified lower electrode A, the surface material is originally in the valence band One of the electrons will be excited and emit a photon to achieve the effect of light-excited fluorescence. By analyzing the photo-excited fluorescence spectrum formed by the photo-excited fluorescence, the structural characteristics of the surface material can be known.

A measurement wavelength range of the light-excited fluorescence spectrum is 350nm to 700nm, and an excitation wavelength is 325nm as an excited state. FIG. 6A is the light-excited fluorescence spectrum of the ZnO nanocolumn array 13 (Pure) and the silver-modified ZnO nanocolumn array (Ag) without annealing; FIG. 6B is the ZnO nanocolumn array 13 and the light-excited fluorescence spectrum of the silver-modified ZnO nanopillar array when it has been annealed. It can be found from FIG. 6A that when there is no annealing, the main peaks of the zinc oxide nanopillar array 13 (Pure) and the silver-modified zinc oxide nanopillar array (Ag) are at a wavelength of about 380nm, while at a wavelength of about 450nm Between to 650nm is the oxygen vacancy peak of the zinc oxide nanopillar array 13 (Pure) and the silver-modified zinc oxide nanopillar array (Ag); and it can be seen in FIG. 6B that the annealed The zinc oxide nanopillar array 13 (Pure) and the silver-modified zinc oxide nanopillar array (Ag) have a significant decrease in the oxygen vacancy value band in the region of 450nm to 650nm, and it is known that the zinc oxide nanopillar array after annealing 13 (Pure) and the silver-modified ZnO nanopillar array (Ag) have a better response to oxygen vacancies.

Step S3, making an upper electrode B: Please refer to FIG. 7, using a laser engraving technique to engrave an electrode pattern on the surface of the indium tin oxide (ITO) film 11 of the indium tin oxide polyester (ITO-PET) substrate , and then use the radio frequency magnetron sputtering system to sputter a metal particle electrode 15 on the electrode pattern, and the metal particle electrode 15 has good electrical conductivity. Preferably, the metal particle electrode 15 is a silver particle electrode, more preferably, the metal particle electrode 15 is the silver particle electrode with a thickness of 100 nm.

Step S4, forming the self-powered gas sensor provided by the present invention: Please refer to FIG. 8 , at least a part of the silver-modified zinc oxide nanopillar array 13 of the silver-modified lower electrode A is connected with the upper electrode B. The indium tin oxide (ITO) thin films 11 are correspondingly bonded to each other, completing the self-powered gas sensor assembly. Wherein, another part of the silver-modified zinc oxide nanopillar array 13 that is not connected with the upper electrode B is exposed to an air middle. Further, each of the zinc oxide nanopillars 131 exposed to the air forms a sensing region 16, so that each of the zinc oxide nanopillars 131 of the sensing region 16 is in contact with nitrogen monoxide (NO) in the air At this time, the silver-modified zinc oxide nano-column array 13 will further generate an output voltage corresponding to the concentration of the nitric oxide (NO) in the air, through which the silver-modified zinc oxide nano-column array 13 corresponds to the NO concentration. The concentration of nitrogen (NO) produces the output of the output voltage difference, and then the corresponding data and ratio between the concentration of nitric oxide (NO) and the output voltage can be obtained.

In the present invention, a pure zinc oxide self-powered gas sensor made by the zinc oxide nano-column array 13 and a silver-modified zinc oxide self-powered gas sensor made by the silver-modified zinc oxide nano-column array are respectively The device is placed in a vacuum chamber carrier, and a nitrogen monoxide flow environment with a flow rate of 5 sccm is provided in the vacuum chamber carrier. And compare the output voltages generated by the pure ZnO self-powered gas sensor and the silver-modified ZnO self-powered gas sensor.

Then give the pure zinc oxide self-powered gas sensor and the silver-modified zinc oxide self-powered gas sensor a mechanical force, so that the silver-modified lower electrode A and the zinc oxide nanocolumn 131 are bent due to the vibration of the mechanical force , and make contact with the upper electrode B to conduct electricity generation. Wherein, the lower electrode of the pure zinc oxide self-powered gas sensor and the silver-modified zinc oxide self-powered gas sensor (a pure zinc oxide lower electrode and the silver-modified lower electrode A) and the upper electrode B respectively pass through a The wire is connected to a detector (Keithly 2400), so that the output voltages generated by the pure ZnO self-powered gas sensor and the silver-modified ZnO self-powered gas sensor can be measured and analyzed.

Referring to Table 1, it can be found that the output voltage of the silver-modified zinc oxide self-powered gas sensor in the nitrogen monoxide gas flow environment with an air flow of 5 sccm is significantly higher than that of the pure zinc oxide self-powered gas sensor It was confirmed that the silver-modified ZnO nanopillar array formed after the modification of the silver nanoparticles 14 has a more sensitive nitric oxide gas sensing capability.

Please refer to Table 2 and Table 3. The present invention further provides the nitrogen oxide gas flow environments of 0 sccm, 5 sccm, 10 sccm, 15 sccm, and 20 sccm respectively for the silver-modified zinc oxide self-powered gas sensor, and measures the silver-modified Zinc oxide self-powered gas sensor produces this output voltage variation. It should be noted that the present invention does not provide any input current during the process of providing the nitrogen oxide flow environment and measuring the output voltage.

S為電壓上升比率；Va為該氧化氮氣流環境0sccm之電壓；Vg為該氧化氮氣流環境5sccm、10sccm、15sccmc或20sccm之該輸出電壓。可以明顯的觀察到，隨著一氧化氮氣流的增加，該銀修飾氧化鋅自供電氣體感測器所產生的該輸出電壓也隨之上升。 Table 2 is the output voltage produced by the silver-modified zinc oxide self-powered gas sensor in different nitrogen monoxide flow environments; Table 3 is the silver-modified zinc oxide self-powered gas in different nitrogen monoxide flow environments A voltage rise ratio of the sensor, the conversion method of the voltage rise ratio is as follows:

S is the voltage increase ratio; Va is the voltage of 0 sccm in the nitrogen oxide gas flow environment; Vg is the output voltage of 5 sccm, 10 sccm, 15 sccmc or 20 sccm in the nitrogen oxide gas flow environment. It can be clearly observed that as the nitrogen monoxide flow increases, the output voltage generated by the silver-modified ZnO self-powered gas sensor also increases.

table 3

The self-powered gas sensor of silver-modified zinc oxide nanocolumns provided by the present invention has the following advantages:

1. The ZnO nanopillar array 13 can be grown by hydrothermal method, which can be completed at low temperature. The simple manufacturing process not only has high success rate and quality, but also reduces pollution due to low overall cost.

2. By giving the mechanical force, the self-powered gas sensor of the silver-modified zinc oxide nanocolumn can convert a mechanical energy into an electrical energy output, realizing the nanoscale power generation function and achieving the effect of reducing the volume.

3. Through the combination of a self-generating system and a gas sensor, the modification of the silver nanoparticles 14 is introduced on the surface of the zinc oxide nanopillars to improve the gas sensing capability of the nitric oxide.

The self-powered gas sensor of the silver-modified zinc oxide nanocolumn provided by the present invention has greatly improved the nitric oxide gas sensing ability and can not only be effectively used in medical treatment to detect an asthma disease through the concentration of nitric oxide gas , also because the self-powered gas sensor of silver-modified zinc oxide nanopillars has the effect of vibration power generation and volume reduction, it can also be modularized in the future as a portable instrument for measuring the concentration of nitric oxide gas exhaled by humans, Contribute to the practical application of clinical and research aspects of medicine.

The silver-modified zinc oxide nanocolumn self-powered gas sensor provided by the present invention can be further combined with an Internet of Things system because it has the ability of self-power generation. For example in a medical In use, the self-powered gas sensor of the silver-modified zinc oxide nano-column is used to measure nitric oxide gas. Mizhu's self-powered gas sensor can send an abnormal signal to the IoT system, so that a corresponding medical team can receive the abnormal signal immediately to achieve better tracking and care functions.

For another example, when the self-powered gas sensor of the silver-modified zinc oxide nanocolumn is applied to a chemical industry, it can monitor whether a harmful gas in a chemical environment is leaked at any time, and uses the ability of self-power generation to achieve an instant response. An emergency signal of a bell or flashing light, and combined with the IoT system to respond to the emergency signal to the relevant units, to achieve timely rescue and prevent major disasters.

Claims (7)

A self-powered gas sensor of silver-modified zinc oxide nanocolumns, which includes: a silver-modified lower electrode, the silver-modified lower electrode includes from bottom to top: an indium tin oxide polyester substrate, the indium tin oxide polyester The surface of the substrate includes an indium tin oxide film; a zinc oxide seed layer, the zinc oxide seed layer is formed on the surface of the indium tin oxide film; a zinc oxide nano column array, the zinc oxide nano column array passes through A hot water method is grown on the surface of the zinc oxide seed layer; and a silver nanoparticle, the silver nanoparticle is sputtered on the surface of the zinc oxide nanopillar array; and an upper electrode, the upper electrode The electrodes include from bottom to top: an indium tin oxide polyester substrate with an indium tin oxide film on the surface, an electrode pattern is engraved on the surface of the indium tin oxide polyester substrate; and a metal particle electrode, which is sputtered on the metal particle electrode The electrode is patterned and has conductive properties; wherein at least a part of the silver-modified zinc oxide nanocolumn array of the silver-modified lower electrode and at least a part of the indium tin oxide film of the upper electrode are joined to each other correspondingly, and the At least a part of the silver-modified zinc oxide nano-column array is exposed to the air to form a sensing area, and the silver-modified zinc oxide nano-column array corresponds to the concentration of nitric oxide in the air to generate an output voltage. The self-powered gas sensor of silver-modified zinc oxide nanocolumns as described in claim 1, using a radio frequency magnetron sputtering system to sputter the zinc oxide seed layer on the surface of the indium tin oxide film, wherein, The zinc oxide seed layer has a thickness of 100 nm. The self-powered gas sensor of silver-modified zinc oxide nanocolumns as described in claim 2, the hot water method step includes: immersing the indium tin oxide polyester substrate sputtered with the zinc oxide seed layer in In a culture solution, wherein the culture solution contains zinc nitrate and hexamethylenetetramine; and The ITO polyester substrate was placed in the oven at 95° C. for 3 hours to form the ZnO nanocolumn array. The self-powered gas sensor of silver-modified zinc oxide nanocolumns as described in claim 3, using a radio frequency sputtering system to sputter the silver nanoparticles on the surface of the zinc oxide nanocolumn array, wherein, the The sputtering conditions of the RF sputtering system are: an argon gas with a flow rate of 20 ml/min (sccm), a pressure of 0.0075 Torr (Torr), an incident power of 50 watts (W) and a time of 20 seconds. In the self-powered gas sensor of silver-modified zinc oxide nanocolumns as described in Claim 4, the metal particle electrode is a silver particle electrode. In the self-powered gas sensor of silver-modified zinc oxide nanocolumns as described in claim 5, the metal particle electrode is the silver particle electrode with a thickness of 100 nm. The self-powered gas sensor of silver-modified zinc oxide nanocolumns as described in claim 6, a mechanical force is given to the self-powered gas sensor, so that at least a part of the zinc oxide nanocolumn array is affected by the mechanical force The silver-modified ZnO nanorod array generates a voltage according to the nitric oxide concentration.

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