A signal-enhanced triboelectric nanogenerator and its applications

Abstract

The present invention discloses a triboelectric nanogenerator with enhanced signal and its applications. The triboelectric nanogenerator includes a bottom support material at the bottommost layer, a lower electrode closely attached to the upper surface of the bottom support material, a solid friction material located on the upper surface of the lower electrode. There is a cavity with an open upper end on the solid friction material, forming a hydrophobic solid friction layer with a fluid channel. A metal wire is embedded along the curved surface of the cavity wall on one side of the cavity, and both ends of the metal wire extend out of the cavity to form an upper electrode. The upper electrode and the lower electrode constitute an electrode layer. By embedding the upper electrode in the hydrophobic solid friction layer, the present invention can effectively utilize frictional charges and enhance the output signal of the triboelectric nanogenerator. At the same time, the present invention realizes the detection of target molecules based on the change in the output signal intensity caused by the influence of target molecules on the charged state of the friction material surface, so it can be used as a fluid biochemical sensor.

Description

Technical Field

[0001] The present invention relates to the field of friction nanogenerators, and in particular to a signal-enhanced friction nanogenerator and applications thereof. Background Art

[0002] At present, self-powered sensor systems without external power sources play an irreplaceable role in environmental protection, biochemical detection, medical care and health monitoring due to their small size, stable performance, fast response speed and low energy consumption. In 2012, Professor Wang Zhonglin of Georgia Institute of Technology and his colleagues jointly invented the triboelectric nanogenerator (TENG), a novel energy harvesting technology that converts mechanical energy into electrical energy by using friction electricity. The rise of this technology has also brought hope to self-powered sensor systems. This technology mainly uses nanomaterials and nano-power generation technology to obtain energy from the environment and convert it into electrical energy. It is a self-sufficient and sustainable energy source, which constitutes the emerging field of nano energy.

[0003] In 2014, Professor Wang Zhonglin used a solid-liquid nano-friction generator to collect vibration energy in water droplets and systematically explained the working mechanism of the water droplet friction nano-generator. However, in this working mode, the friction charge mainly comes from the electrostatic induction process between the lower electrode and the friction layer. This interface effect is very unfavorable for the transfer of friction charge, which in turn causes a decrease in output performance.

[0004] Therefore, improving the output signal of the friction nanogenerator is a technical problem that needs to be solved urgently. Summary of the invention

[0005] In view of this, the present invention provides a device with fast response speed, simple device structure, low cost, and no need for energy supply module. It can not only enhance the output signal of the friction nanogenerator, but also be used as a fluid biochemical sensor to detect the presence and concentration of target molecules in the fluid.

[0006] The technical solution adopted by the present invention is as follows: a signal-enhanced friction nanogenerator is provided, comprising: a bottom support material located at the bottom layer, a lower electrode closely attached to the upper surface of the bottom support material, and a solid friction material located on the upper surface of the lower electrode, wherein a cavity with an open upper end is provided on the solid friction material to form a hydrophobic solid friction layer with a fluid channel, a metal wire is embedded in one side of the cavity along the curved surface of the cavity wall, and both ends of the metal wire extend out of the cavity to form an upper electrode, and the upper electrode and the lower electrode constitute an electrode layer.

[0007] Preferably, the lower electrode is located at a midline position of the bottom supporting material.

[0008] Preferably, the cavity is in the shape of a semi-cylinder, a cylinder or a cuboid.

[0009] Optionally, the bottom support material includes a glass slide, ITO, or a plastic sheet with a certain structural strength.

[0010] Preferably, the solid friction material is in the shape of a cuboid, and its lower surface coincides with the upper surface of the bottom support material.

[0011] Optionally, the solid friction material includes polydimethylsiloxane, polytetrafluoroethylene, polystyrene, or polyimide.

[0012] Preferably, the diameter of the upper electrode ranges from 0.1 to 0.6 mm.

[0013] Optionally, the material of the electrode layer includes copper, aluminum, gold, or silver.

[0014] The present invention also provides an application of a friction nanogenerator with enhanced signal, including:

[0015] Inject the fluid to be tested into the hydrophobic solid friction layer with a fluid channel. The friction nanogenerator swings periodically under the action of an external mechanical force, causing the fluid to be tested to roll back and forth. The friction nanogenerator exports and utilizes the electrostatic energy after the fluid to be tested comes into contact with the solid friction layer, and realizes the detection of target molecules based on the change in the output signal intensity caused by the influence of the target molecules in the fluid to be tested on the charged state of the friction material surface.

[0016] Preferably, the fluid to be tested is a mixed fluid containing urea and urease. The hydroxide ions generated by the catalytic decomposition of urea by urease increase the number of negatively charged surfaces of the solid friction material, thereby causing a regular increase in the output signal intensity of the friction nanogenerator to achieve urea detection.

[0017] The technical solution provided by the present invention has the following beneficial effects:

[0018] The present invention provides a device with a fast response speed, a simple structure, a low cost, and no need for an energy supply module. By embedding an upper electrode in the solid friction layer, the frictional charges can be effectively utilized to enhance the output signal of the friction nanogenerator. At the same time, the present invention realizes the detection of target molecules based on the change in the output signal intensity caused by the influence of the target molecules on the charged state of the friction material surface. Description of the Drawings

[0019] The present invention will be further described below in conjunction with the drawings and embodiments. In the drawings:

[0020] Figure 1 is a schematic structural diagram of the friction nanogenerator with enhanced signal in the present invention.

[0021] Figure 2It is the output performance result diagram of the single electrode of the triboelectric nanogenerator in the present invention.

[0022] Figure 3 It is the output performance result diagram of the triboelectric nanogenerator when the diameters of the upper electrode copper wires are 0.1, 0.2, 0.3, 0.4, 0.5, and 0.6 mm in the present invention.

[0023] Figure 4 It is the output performance result diagram of the triboelectric nanogenerator with different concentrations of NaOH solution in the present invention.

[0024] Figure 5 It is the output performance result diagram of the triboelectric nanogenerator after adding urease to artificial urine in the present invention.

[0025] Figure 6 It is the output performance result diagram of the triboelectric nanogenerator after adding urease to different urea solutions in the present invention.

[0026] Figure 7 It is the output performance result diagram and the high performance liquid chromatography test result diagram of the triboelectric nanogenerator after adding urease to 50 μM urea solution after cultivating peas for different days in the present invention.

[0027] Figure 8 It is the correlation diagram between the urea concentration measured by high performance liquid chromatography and the measured voltage change value in the present invention. Detailed implementation manners

[0028] For a clearer understanding of the technical features, objectives, and effects of the present invention, the detailed implementation manners of the present invention will now be described in detail with reference to the accompanying drawings.

[0029] Please refer to Figure 1 , an embodiment of the present invention provides a triboelectric nanogenerator with signal enhancement, including: a bottom support material 3 located at the bottom layer, a lower electrode 11 closely attached to the upper surface of the bottom support material 3, a solid friction material located on the upper surface of the lower electrode 11, a cavity with an open upper end is provided on the solid friction material to form a hydrophobic solid friction layer 2 with a fluid channel, a metal wire is embedded along the curved surface of the cavity wall on one side of the cavity, and both ends of the metal wire extend out of the cavity to form an upper electrode 12, and the upper electrode 12 and the lower electrode 11 constitute an electrode layer 1.

[0030] The preparation process of this triboelectric nanogenerator is as follows:

[0031] 1) Select the bottom support material 3;

[0032] 2) Prepare the lower electrode 11;

[0033] 3) Prepare the hydrophobic solid friction layer 2 with a fluid channel and the upper electrode 12;

[0034] 4) Fabricate a triboelectric nanogenerator.

[0035] Specifically, in this embodiment, a glass slide is selected as the bottom support material 3. The surface of the glass slide is wiped clean and placed in a petri dish. A copper tape is attached to the upper surface of the glass slide, and the position is at the midline of the glass slide. The lower electrode 11 is fabricated on the upper surface of the glass slide. In other embodiments, the copper tape can also be replaced with an aluminum tape or other metal tapes with good electrical conductivity, or metals such as gold, silver, aluminum, and copper can be fabricated as the lower electrode 11 by sputtering method;

[0036] A copper wire (or a conductive metal wire such as a nickel wire or an aluminum wire) is bundled on an acrylic rod with a length of 5 cm and a diameter of 1 cm (or a rod-shaped structure made of other plastic materials or a glass rod) and placed in the middle of the glass slide. Subsequently, the solid friction material PDMS is poured into the petri dish. After the PDMS is dried, the acrylic rod (or a rod-shaped structure made of other plastic materials or a glass rod) is taken out, and a hydrophobic solid friction layer 2 with a fluid channel is fabricated, and the copper wire is embedded on the surface of the hydrophobic solid friction layer 2, and the upper electrode 12 is fabricated.

[0037] The upper electrode 12, the lower electrode 11, and the hydrophobic solid friction layer 2 with a fluid channel constitute a triboelectric nanogenerator.

[0038] Connect the copper wires led out from the upper electrode 12 and the lower electrode 11 to the positive and negative poles of an oscilloscope for measuring the output voltage of the triboelectric nanogenerator.

[0039] In this embodiment, the output voltage of the triboelectric nanogenerator can be changed by adjusting the diameter of the copper wire of the upper electrode 12 and the type of fluid in the fluid channel.

[0040] To measure the output performance of copper wires with different diameters of the upper electrode 12, the diameters of the copper wires are set to be 0.1, 0.2, 0.3, 0.4, 0.5, and 0.6 mm respectively, and the fluid in the fluid channel is controlled to be deionized water, and the output voltage is displayed by an oscilloscope. From Figure 2 and Figure 3 It can be seen that the presence of the upper electrode 12 can significantly enhance the output signal of the triboelectric nanogenerator, and when the diameter of the copper wire of the upper electrode 12 is 0.4 mm, the output signal reaches the highest at 16 V. Therefore, compared with the single-electrode triboelectric nanogenerator, the presence of the upper electrode 12 can more effectively transfer charges and greatly enhance the output signal.

[0041] To further explore the actual application performance of the fabricated triboelectric nanogenerator and investigate the output performance of the triboelectric nanogenerator in different solutions, NaOH solutions with concentrations of 0, 0.1, 1, 2, 5, and 10 mM, artificial urine, urea solutions with different concentrations, and urea solutions after cultivating peas for different days were selected for experiments. From Figure 4 the results, it can be seen that the output voltage of NaOH solutions with different concentrations shows a trend of first increasing and then decreasing. When the concentration of the NaOH solution is 1 mM, the output signal reaches the maximum value of 25.8 V. The reason may be that at low concentrations, OH - will react with the Si-O-Si bonds on the surface of polydimethylsiloxane, thereby generating Si-O bonds with stronger polarity, increasing the number of negative charges on the surface of the friction material, and thus enhancing the output performance of the device. When the concentration continues to increase, Na + in the solution will adsorb on the surface of the solid friction layer, resulting in the shielding of some negative charges on the surface of the friction material and reducing the output performance. From this result, it can be seen that when the pH of the fluid to be measured increases, the output electrical signal can be increased. In addition, the decomposition reaction of urea catalyzed by urease to generate OH - can also increase the pH of the solution. In view of the fact that the reaction of urea and urease can increase the pH value of the solution, thereby increasing the number of negative charges on the surface of the friction material and enhancing the output signal of the device, this feature can be used to detect urea in the fluid to be tested. As Figure 5 shown, artificial urine was selected as the fluid to be measured and urease was added. The test results show that the fabricated triboelectric nanogenerator can detect the enhancement of the voltage signal within 30 s, indicating that the triboelectric nanogenerator has the characteristic of fast response speed. To further determine the urea content in the solution, a series of urea solutions with different concentrations were tested. From Figure 6 the results, it can be seen that the output signal continuously increases with the increase of the urea content. The above results demonstrate the ability of the triboelectric nanogenerator as a urea sensor. Using a 50 μM urea solution as the experimental material, peas were cultivated, and the urea content in the urea solution after cultivating peas for different days was monitored. To ensure the accuracy of the test, high-performance liquid chromatography was used to analyze the results at the same time. From Figure 7As can be seen from the results, as the number of days passed, the output voltage signal gradually decreased, indicating that the urea content in the urea solution gradually decreased, which was consistent with the change law of high performance liquid chromatography. In addition, it can be seen that the urea concentration in the solution after 7 days of cultivation measured by high performance liquid chromatography was about 4 μM, and the self-powered biochemical sensor also responded to such a low-concentration urea solution. The high performance liquid chromatography test showed that after 9 days of cultivation, the urea concentration in the culture medium decreased to nearly 3 μM. At this time, the output voltage of the biochemical sensor hardly changed. Even so, the detection sensitivity could still meet the actual needs. Moreover, there was a very good correlation between the urea concentration measured by high performance liquid chromatography and the measured voltage change value, and the correlation coefficient was 0.988, as Figure 8 shown. It shows that the self-powered fluid biochemical sensor has good sensitivity and specificity, demonstrating its potential application value for urea concentration monitoring in smart agriculture.

[0042] Similarly, based on the change in the output signal intensity of the triboelectric nanogenerator caused by the specific effect of other types of target molecules on the charged state of the solid friction material surface, different types of target molecule detection can be achieved.

[0043] It should be noted that in this article, the terms "including", "comprising" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or system including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such a process, method, article or system. Without further limitations, an element defined by the statement "including one..." does not exclude the existence of another identical element in the process, method, article or system including that element.

[0044] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments. Among the several device unit claims listing several devices, several of these devices can be specifically embodied by the same hardware item. The use of the words first, second, and third, etc. does not indicate any order and these words can be interpreted as identifiers.

[0045] The above are only the preferred embodiments of the present invention and do not limit the patent scope of the present invention accordingly. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, shall be equally included in the patent protection scope of the present invention.

Claims

1. A triboelectric nanogenerator with signal enhancement, characterized in that, Comprising: A bottom support material (3) located at the bottommost layer, a lower electrode (11) closely attached to the upper surface of the bottom support material (3), and a solid friction material located on the upper surface of the lower electrode (11). A cavity with an open upper end is provided in the solid friction material to form a hydrophobic solid friction layer (2) having a fluid channel. A metal wire is embedded along the curved surface of the cavity wall on one side of the cavity, and both ends of the metal wire extend out of the cavity to form an upper electrode (12). The upper electrode (12) and the lower electrode (11) constitute an electrode layer (1).

2. The signal-enhanced triboelectric nanogenerator according to claim 1, wherein The lower electrode (11) is located at the midline position of the bottom support material (3).

3. The signal-enhanced triboelectric nanogenerator according to claim 1, wherein The cavity is in the shape of a semi-cylinder, a cylinder or a cuboid.

4. The signal-enhanced triboelectric nanogenerator according to claim 1, wherein The bottom support material (3) is a glass slide, ITO or a plastic sheet.

5. The signal-enhanced triboelectric nanogenerator according to claim 1, wherein The solid friction material is in the shape of a cuboid, and its lower surface coincides with the upper surface of the bottom support material (3).

6. The signal-enhanced triboelectric nanogenerator according to claim 1, wherein The solid friction material includes polydimethylsiloxane, polytetrafluoroethylene, polystyrene or polyimide.

7. The signal-enhanced triboelectric nanogenerator according to claim 1, wherein The diameter of the upper electrode (12) ranges from 0.1 to 0.6 mm.

8. The signal-enhanced triboelectric nanogenerator according to claim 1, wherein The material of the electrode layer (1) includes copper, aluminum, gold or silver.

9. Application of the signal-enhanced triboelectric nanogenerator according to any one of claims 1-8, characterized in that, Comprising: Inject a fluid to be tested into the hydrophobic solid friction layer (2) having a fluid channel. The triboelectric nanogenerator swings periodically under the action of an external mechanical force, causing the fluid to be tested to roll back and forth. The triboelectric nanogenerator derives and utilizes the electrostatic energy after the fluid to be tested comes into contact with the solid friction layer (2), and realizes the detection of target molecules based on the change in the output signal intensity caused by the influence of the target molecules in the fluid to be tested on the charged state of the friction material surface.

10. The application of the triboelectric nanogenerator with enhanced signal according to claim 9, wherein The fluid to be tested is a mixed fluid containing urea and urease. The hydroxide ions generated by the catalytic decomposition of urea by urease increase the number of negatively charged surfaces of the solid friction material, thereby causing a regular increase in the output signal intensity of the triboelectric nanogenerator to achieve urea detection.

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