Piezoelectric sensor

Abstract

The invention provides a piezoelectric sensor. The piezoelectric sensor includes: a first substrate; a first conductive layer adjacent to the first substrate; a second substrate; a second conductive layer adjacent to the second substrate; and a first structure between the first conductive layer and the second conductive layer, where the first structure includes: a first layer having a first carbon-based material; a plurality of second structures having piezoelectricity, each of the plurality of second structures including: a second layer having a second carbon-based material; a third layer adjacent to the second layer wherein the third layer comprises a two-dimensional anomalous stoichiometric crystalline material, such as Na2Cl crystals.

Description

Technical Field

[0001] The present disclosure generally relates to a piezoelectric sensor, and more particularly to a piezoelectric sensor using a carbon-based material (e.g., graphene oxide) and also using a two-dimensional anomalous stoichiometric crystal such as Na 2 Piezoelectric sensor made of Cl crystal. Background Art

[0002] A piezoelectric sensor is a device that uses the piezoelectric effect to convert a mechanical (or pressure) signal into an electrical signal to measure its changes.

[0003] Some common and widely used piezoelectric materials include lead zirconate titanate (PZT), barium titanate (BTO), zinc oxide (ZnO) and polyvinylidene fluoride (PVDF). In practical applications, piezoelectric sensors or pressure sensors based on piezoelectric mechanism made using these piezoelectric materials can usually provide good sensitivity and / or fast response speed. However, in order to meet the requirements of the next generation of pressure sensors, the performance of piezoelectric sensors still needs to be further improved.

[0004] It would therefore be desirable to produce a piezoelectric sensor that takes into account at least some of the above-mentioned issues as well as other possible issues. Summary of the invention

[0005] Exemplary embodiments of the present disclosure relate to using carbon-based materials and two-dimensional Na 2 Piezoelectric sensor of Cl crystal. Compared with traditional and existing pressure sensors, exemplary embodiments can provide piezoelectric sensors or pressure sensors based on piezoelectric mechanism with higher sensitivity, lower pressure detection limit and / or faster response speed. In addition, exemplary embodiments can provide piezoelectric sensors or pressure sensors based on piezoelectric mechanism with flexibility, self-powered capability and repeatable electromechanical conversion.

[0006] Therefore, the present disclosure includes, but is not limited to, the following exemplary embodiments.

[0007] Some exemplary embodiments provide a piezoelectric sensor. The piezoelectric sensor includes a first substrate, a first conductive layer adjacent to the first substrate, a second substrate, a second conductive layer adjacent to the second substrate; and a first structure between the first conductive layer and the second conductive layer. The first structure includes a first layer having a first carbon-based material and a plurality of second structures having piezoelectricity. Each of the plurality of second structures includes a second layer having a second carbon-based material and a third layer adjacent to the second layer. The third layer includes a two-dimensional anomalous stoichiometric crystalline material.

[0008] In some embodiments, the first substrate and the second substrate include a first insulating film and a second insulating film, respectively.

[0009] In some embodiments, the first insulating film is made of a material selected from any one of the following material groups: polyimide (PI), ethylene-vinyl acetate copolymer (EVA), polyvinyl chloride (PVC), polydimethylsiloxane (PDMS), polyvinyl alcohol (PVA), polypropylene (PP) and polyethylene terephthalate (PET), and the second insulating film is made of a material selected from any one of the following material groups: polyimide (PI), ethylene-vinyl acetate copolymer (EVA), polyvinyl chloride (PVC), polydimethylsiloxane (PDMS), polyvinyl alcohol (PVA), polypropylene (PP) and polyethylene terephthalate (PET).

[0010] In some embodiments, the first conductive layer and the second conductive layer include a first electrode and a second electrode, respectively.

[0011] In some embodiments, the first electrode is made of a material selected from any one of the following material groups: gold (Au), silver (Ag), platinum (Pt), titanium (Ti), chromium (Cr), copper (Cu), nickel (Ni), aluminum (Al), graphene and MXene, and the second electrode is made of a material selected from any one of the following material groups: gold (Au), silver (Ag), platinum (Pt), titanium (Ti), chromium (Cr), copper (Cu), nickel (Ni), aluminum (Al), graphene and MXene.

[0012] In some embodiments, the first lead is connected to the first electrode and the second lead is connected to the second electrode.

[0013] In some embodiments, the first conductive layer contacts the first layer, and the second conductive layer contacts the second layer of one of the plurality of second structures.

[0014] In some embodiments, the first structure is a film.

[0015] In some embodiments, the first carbon-based material includes graphene oxide, reduced graphene oxide, carbon nanotubes, or fullerenes, and the second carbon-based material includes graphene oxide, reduced graphene oxide, carbon nanotubes, or fullerenes.

[0016] In some embodiments, the piezoelectric sensor further includes a tape for packaging the piezoelectric sensor.

[0017] In some embodiments, the third layer includes Na 2 Cl crystal material.

[0018] These and other features, aspects and advantages of the present disclosure will become apparent by reading the following detailed description and the accompanying drawings, which are briefly described below. The present disclosure includes any combination of two, three, four or more features or elements set forth in the present disclosure, whether or not such features or elements are explicitly combined or otherwise stated in the specific exemplary embodiments described herein. The present disclosure is intended to be read as a whole, such that any separable features or elements of the present disclosure should be considered combinable in any aspect and exemplary embodiment thereof, unless the context of the present disclosure clearly provides otherwise.

[0019] Therefore, it should be understood that the description of the content of the present invention is provided only for the purpose of summarizing some exemplary embodiments in order to provide a basic understanding of some aspects of the present disclosure. Therefore, it should be understood that the above exemplary embodiments are only examples and should not be interpreted as narrowing the scope or spirit of the present disclosure in any way. Other exemplary embodiments, aspects and advantages will become apparent from the following detailed description in conjunction with the accompanying drawings, which illustrate the principles of some of the exemplary embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Having described exemplary embodiments of the present disclosure in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and in which:

[0021] Figure 1A and 1B The structure of a piezoelectric sensor according to some embodiments of the present disclosure is shown;

[0022] Figure 2 Figure 2 shows Na adsorbed on a graphene sheet according to some embodiments of the present disclosure. 2 The structure of a Cl crystal, which is represented by Na 2 Cl@graphene;

[0023] Figure 3 shows a piezoelectric sensor encapsulated with tape according to some embodiments of the present disclosure; and

[0024] Figure 4 A piezoelectric sensor array according to some embodiments of the present disclosure is shown. DETAILED DESCRIPTION

[0025] Some embodiments of the present disclosure will now be described more fully below with reference to the accompanying drawings, in which some but not all embodiments of the present disclosure are shown. In fact, the various embodiments of the present disclosure can be implemented in a variety of different forms and should not be construed as limited to the embodiments set forth herein; on the contrary, these exemplary embodiments are provided to make the present disclosure thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art. For example, unless otherwise stated, references to first, second, etc. should not be construed as implying a particular order. The same reference numerals always refer to the same elements.

[0026] Figure 1A A piezoelectric sensor 100 according to some embodiments of the present disclosure is shown. As shown, the piezoelectric sensor 100 includes a first substrate 101 and a first conductive layer 102 adjacent to the first substrate 101. The piezoelectric sensor 100 also includes a second substrate 109 and a second conductive layer 110 adjacent to the second substrate 109.

[0027] In some embodiments, the first substrate 101 and the second substrate 109 include a first insulating film and a second insulating film, respectively. In some embodiments, the first insulating film is made of a material selected from any one of the following material groups: polyimide (PI), ethylene-vinyl acetate copolymer (EVA), polyvinyl chloride (PVC), polydimethylsiloxane (PDMS), polyvinyl alcohol (PVA), polypropylene (PP) and polyethylene terephthalate (PET), and the second insulating film is made of a material selected from any one of the following material groups: polyimide (PI), ethylene-vinyl acetate copolymer (EVA), polyvinyl chloride (PVC), polydimethylsiloxane (PDMS), polyvinyl alcohol (PVA), polypropylene (PP) and polyethylene terephthalate (PET).

[0028] In some embodiments, the first conductive layer 102 and the second conductive layer 110 include a first electrode and a second electrode, respectively. In some embodiments, the first electrode is made of a material selected from any one of the following material groups: gold (Au), silver (Ag), platinum (Pt), titanium (Ti), chromium (Cr), copper (Cu), nickel (Ni), aluminum (Al), graphene, and MXene, and the second electrode is made of a material selected from any one of the following material groups: gold (Au), silver (Ag), platinum (Pt), titanium (Ti), chromium (Cr), copper (Cu), nickel (Ni), aluminum (Al), graphene, and MXene. The first electrode may be a positive electrode, and the second electrode may be a negative electrode.

[0029] In some embodiments, the first wire 103 is connected to the first electrode and is led out from the first conductive layer 102. The second wire 111 is connected to the second electrode and is led out from the second conductive layer 110.

[0030] In some embodiments, the piezoelectric sensor 100 includes a first structure 112 located between the first conductive layer 102 and the second conductive layer 110. The first structure 112 includes a first layer 104 having a first carbon-based material and a plurality of second structures. In some embodiments, the first layer 104 may be a layer having graphene oxide (GO), and thus the first layer may be denoted as GO layer 104.

[0031] In some embodiments, each of the plurality of second structures may have the same structure: including a second layer 106 having a second carbon-based material and a third layer 105 adjacent to the second layer. In some embodiments, the second layer 106 may be a layer having graphene oxide (GO), and thus the second layer may be referred to as a GO layer 106. In some embodiments, the third layer 105 includes a two-dimensional anomalous stoichiometric crystalline material such as Na 2 Cl crystal, so the third layer 105 can be represented as Na 2 Cl layer 105. The second structure as a whole has piezoelectricity. The piezoelectricity is mainly attributed to the Na 2 Cl crystals, they can produce relatively large deformation under small pressure, resulting in strong electrostatic polarization. In some embodiments, the preparation of piezoelectric sensors uses carbon-based materials such as graphene oxide, and also uses two-dimensional anomalous stoichiometric crystal materials such as K 2 Cl, CaCl, MgCl, NaCl 2 Compared with known stable crystals under normal temperature and pressure conditions, such as NaCl with a stoichiometric ratio of 1:1 and CaCl with a stoichiometric ratio of 1:2, 2 , MgCl with a stoichiometric ratio of 1:2 2 , NaCl with a stoichiometric ratio of 1:2 2 etc. The stoichiometric ratios of these two-dimensional anomalous stoichiometric crystals are unconventional.

[0032] In some embodiments, in the first structure 112, the second structure is repeated multiple times (e.g., hundreds to thousands of times) and stacked. Figure 1A As shown, the second structure includes GO layer 106 and Na 2 Cl layer 105. And the second structure is repeated multiple times and stacked, such as Figure 1A The last repeated second structure in the first structure 112 includes a GO layer 108 and a Na 2 Cl layer 107. In some examples, the second structure can be represented by Na 2 Cl@GO.

[0033] In some embodiments, the first carbon-based material in layer 104 includes graphene oxide, reduced graphene oxide, carbon nanotubes, or fullerenes, and the second carbon-based material in layer 106 or 108 includes graphene oxide, reduced graphene oxide, carbon nanotubes, or fullerenes.

[0034] In some embodiments, the first conductive layer 102 is in direct contact with a first layer having a first carbon-based material (eg, GO layer 104 ), and the second conductive layer 110 is in direct contact with a second layer of one of the plurality of second structures (eg, GO layer 108 ).

[0035] In some embodiments, the first structure 112 includes or forms a thin film.

[0036] Figure 1B The second structure 120 according to some embodiments of the present disclosure is shown. As shown, for example, the second structure 120 may include a GO layer 106 and a Na 2 Cl layer 105. The second structure 120 is repeated multiple times and is as mentioned above Figure 1A Stacked together as described.

[0037] In some examples, fabrication of piezoelectric sensor 100 can be performed as follows.

[0038] First, prepare a graphene oxide (GO) suspension. Graphite powder can be placed in concentrated sulfuric acid H 2 SO 4 , K 2 S 2 O 8 and P 2 O 5 The mixed solution was stirred continuously for 12 to 24 hours. The mixture was then diluted with deionized water, centrifuged, and washed with deionized water. After drying, the pre-oxidized graphite flakes were obtained and placed in a high concentration of H 2 SO 4 and potassium permanganate, diluted with deionized water, followed by the addition of 30% H 2 O 2 . These further oxidized graphite sheets are centrifuged and washed with 1:10 HCl aqueous solution and deionized water in turn to remove various ions. Then, a few layers of graphene oxide (GO) are separated by centrifugation at a speed of 4000 rpm. The concentration of the GO suspension prepared in this way is about 5 mg / mL. The GO suspension is dialyzed with a dialysis bag (e.g., a molecular weight cutoff of 14,000) for 7 days to remove adsorbed metal ions.

[0039] Then, a GO film was prepared by spraying a GO suspension (20 μL, 5 mg / mL) on a polyimide (PI) substrate, followed by drying at 60 °C for 6 h. The prepared GO film was then drop-casted with a diluted NaCl solution (0.01 mol / L) and kept in air for 2 h. Next, the GO suspension was sprayed on the film again and dried at 60 °C for another 6 h to form NaCl in the GO film. 2 Cl crystals, which are expressed as Na 2 Cl@GO.Na 2 The thickness of the Cl@GO film is adjustable, and its thickness can range from about ~100 nm to ~μm depending on the number of spraying times of the GO suspension and the diluted sodium chloride solution.

[0040] In some embodiments, a Pt electrode with a thickness of 100 nm and a size of 0.5 cm×0.5 cm is prepared on a PI substrate with a thickness of 10 μm by using a magnetron sputtering method, that is, an electrode with PI as a substrate (such as substrate 101) and Pt as a conductive channel (such as conductive layer 102), that is, a Pt / PI electrode. 2 The Cl@GO film is sandwiched between two Pt / PI electrodes or between two composite films of 100 nanometers of Pt and 10 μm of PI. And the wires 103 and 111 are drawn out from the two Pt / PI electrodes. The wires 103 and 111 are soldered to the Pt surface by silver paste. Then, the piezoelectric sensor 100 can be edge-encapsulated using 3M Kapton tape 301.

[0041] In some examples, Na 2 The size of the Cl@GO film can be adjusted according to application requirements.

[0042] Figure 2 The Na according to some embodiments of the present disclosure is shown. 2 The structure of Cl@graphene 200. 2 The formation of Cl crystals is attributed to Na + Na between the cation and the π-conjugated benzene ring + -π interaction, in Figure 2 In FIG. 2 , structure 200 only shows the graphene portion of the graphene oxide that does not contain an oxidized functional group. Structure 200 may correspond to Figure 1B In some examples, the structure 200 includes two parts, namely, Na 2 Cl layer 201 and a carbon-based material or graphene layer 202. Layer 201 may correspond to Na 2 Cl layer 105, and the carbon-based material or graphene layer 202 may correspond to Figure 1B GO layer 106 in.

[0043] Figure 3 FIG. 3 shows a piezoelectric sensor 300 packaged with tape 301 according to some embodiments of the present disclosure. The piezoelectric sensor 300 may correspond to Figure 1A 1. The piezoelectric sensor 100 in FIG. As shown in the figure, the piezoelectric sensor 300 includes a package with a tape 301 to protect the piezoelectric sensor 300. The piezoelectric sensor 300 also includes wires 103 and 111 for measuring the change of the electrical signal to determine the change of the pressure signal. For example, the wires 103 and 111 can be connected to an oscilloscope or a voltmeter to measure the change.

[0044] Figure 4 A piezoelectric sensor array 400 according to some embodiments of the present disclosure is shown. As shown, the piezoelectric sensor array 400 includes a plurality of piezoelectric sensors 100 connected in series. One piezoelectric sensor 100 in the array 400 may include a wire 103, and another piezoelectric sensor 100 in the array 400 may include a wire 111 for measuring pressure changes by observing voltage changes. The piezoelectric sensor array 400 can increase the output voltage and thus the output power, and can be used for energy collection and storage.

[0045] Benefiting from the teachings proposed in the foregoing description and the related drawings, those skilled in the art to which the present disclosure belongs will think of many modifications and other embodiments of the present disclosure. Therefore, it should be understood that the present disclosure is not limited to the specific embodiments disclosed, and modifications and other embodiments are intended to be included within the scope of the appended claims. In addition, although the foregoing description and the related drawings describe the exemplary embodiments in the context of specific example combinations of elements and / or functions, it should be understood that alternative embodiments can provide different combinations of elements and / or functions without departing from the scope of the appended claims. In this regard, for example, a combination of elements and / or functions different from the elements and / or functions explicitly described above is also contemplated, as described in some of the appended claims. Although specific terms are used herein, they are only used for general and descriptive meanings, not for limiting purposes.

Claims

1. A piezoelectric sensor comprising: first base; a first conductive layer adjacent to the first substrate; Second base; a second conductive layer adjacent to the second substrate; and A first structure between the first conductive layer and the second conductive layer, wherein the first structure comprises: a first layer having a first carbon-based material; A plurality of second structures having piezoelectricity, each of the plurality of second structures comprising: a second layer having a second carbon-based material; and A third layer is adjacent to the second layer, wherein the third layer comprises a two-dimensional anomalous stoichiometric crystalline material.

2. The piezoelectric sensor according to claim 1, wherein: The first substrate and the second substrate include a first insulating film and a second insulating film, respectively.

3. The piezoelectric sensor according to claim 2, wherein: The first insulating film is made of a material selected from the following material group: polyimide (PI), ethylene-vinyl acetate copolymer (EVA), polyvinyl chloride (PVC), polydimethylsiloxane (PDMS), polyvinyl alcohol (PVA), polypropylene (PP) and polyethylene terephthalate (PET), and the second insulating film is made of a material selected from the following material group: polyimide (PI), ethylene-vinyl acetate copolymer (EVA), polyvinyl chloride (PVC), polydimethylsiloxane (PDMS), polyvinyl alcohol (PVA), polypropylene (PP) and polyethylene terephthalate (PET).

4. The piezoelectric sensor according to claim 1, wherein: The first conductive layer and the second conductive layer include a first electrode and a second electrode, respectively.

5. The piezoelectric sensor according to claim 4, wherein: The first electrode is made of a material selected from any one of the following material groups: gold (Au), silver (Ag), platinum (Pt), titanium (Ti), chromium (Cr), copper (Cu), nickel (Ni), aluminum (Al), graphene and MXene, and the second electrode is made of a material selected from any one of the following material groups: gold (Au), silver (Ag), platinum (Pt), titanium (Ti), chromium (Cr), copper (Cu), nickel (Ni), aluminum (Al), graphene and MXene.

6. The piezoelectric sensor according to claim 4, wherein: The first lead is connected to the first electrode, and the second lead is connected to the second electrode.

7. The piezoelectric sensor according to claim 1, wherein: The first conductive layer contacts the first layer, and the second conductive layer contacts a second layer of one of the plurality of second structures.

8. The piezoelectric sensor according to claim 1, wherein: The first structure is a thin film.

9. The piezoelectric sensor according to claim 1, wherein: The first carbon-based material includes graphene oxide, reduced graphene oxide, carbon nanotube or fullerene, and the second carbon-based material includes graphene oxide, reduced graphene oxide, carbon nanotube or fullerene.

10. The piezoelectric sensor according to claim 1, wherein: The piezoelectric sensor further comprises an adhesive tape for packaging the piezoelectric sensor.

11. The piezoelectric sensor according to claim 1, wherein: The third layer includes Na2Cl crystalline material.

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