Compression type DC triboelectric sensor and preparation method and application thereof

Abstract

The invention relates to a compression type direct current triboelectric sensor and a preparation method and application thereof, the sensor comprises a main body and an insulating part for packaging the main body, the main body comprises two metal electrodes arranged oppositely and a dielectric material layer located between the two metal electrodes, the dielectric material layer is formed by laying a granular dielectric material between two metal electrodes, charges lost by electrostatic breakdown are greatly inhibited through an interface Schottky barrier formed by layer-by-layer assembly, and quick response to static pressure and dynamic pressure is realized.

Description

Technical Field

[0001] The present invention relates to the technical fields of DC self - power supply and sensors, and particularly relates to a compression - type DC triboelectric sensor, a preparation method thereof, and an application thereof. Background Art

[0002] Flexible sensors play an important role in the fields of biomedicine, robotics, and human - machine interaction. Such sensors need to have functions of dynamic force detection (such as pulse, movement), high - frequency vibration perception (such as speech recognition), and self - power supply. As an emerging technology, the triboelectric nanogenerator (TENG) converts mechanical energy into electrical signals through triboelectrification and electrostatic induction. With advantages such as low cost, flexibility, and environmental friendliness, it has become an ideal solution for self - powered sensors. However, existing TENGs still face problems such as limited output performance, triboelectric noise interference, air breakdown caused by electrostatic fields, and charge dissipation. Although performance has been improved through strategies such as material modification, structure optimization, and polarization charge injection, problems such as signal attenuation, insufficient sensitivity, and interface wear, as well as the need for a rectification device for self - power supply, restrict their practical applications.

[0003] In triboelectric - based nanogenerators and sensors, during the friction process, a large amount of charge accumulates in the TENG, thus forming a strong electrostatic field, which greatly affects the performance of triboelectric sensors. If this electric field becomes strong enough, it may exceed the dielectric breakdown strength of air, resulting in ionization and unwanted charge loss. Although researchers have made great efforts and achieved great results, for example, the charge collection electrode (CCE) can capture energy and generate a DC output, the defects of sliding wear and insufficient static force detection accuracy have not been effectively solved, and it is urgent to further break through the technical bottleneck to achieve a wider range of application scenarios. Summary of the Invention

[0004] The first technical problem to be solved by the present invention is to provide a compression - type DC triboelectric sensor for the above - mentioned existing technology. This compression - type DC triboelectric sensor solves the problems that existing triboelectric sensors cannot detect static pressure, it is difficult to achieve DC output under static pressure, the response time and recovery time are slow, and the low - pressure detection limit is high.

[0005] The second technical problem to be solved by the present invention is to provide a preparation method of the above - mentioned compression - type DC triboelectric sensor for the above - mentioned existing technology.

[0006] The third technical problem to be solved by the present invention is to provide an application of the above - mentioned compression - type DC triboelectric sensor for the above - mentioned existing technology.

[0007] The technical solution adopted by the present invention to solve the above first technical problem is as follows: A compression-type DC triboelectric sensor, characterized in that it includes a main body and an insulating member encapsulating the main body. The main body includes two relatively arranged metal electrodes and a dielectric material layer located between the two metal electrodes. The dielectric material layer is formed by spreading particulate dielectric material between the two metal electrodes. Both metal electrodes are flexible electrodes.

[0008] In the above solution, the material of one of the metal electrodes is copper (Cu), or gold, or silver, or platinum, or aluminum; the material of the other metal electrode is aluminum (Al).

[0009] In the above solution, the dielectric material is aluminum oxide particles, or soil particles, or silicon dioxide particles.

[0010] Preferably, the main body further includes a graphene oxide film and / or a reduced graphene oxide film located between the metal electrode and the dielectric material layer.

[0011] In this way, two Schottky barriers are formed through the interface between Al / Al2O3 / GO / rGO (GO is graphene oxide, rGO is reduced graphene oxide), which can effectively reduce charge dissipation. Continuously pressing the sensor will generate an open-circuit voltage of about 2V and a DC current of 100 μA, realizing the detection of physiological signals and acoustic phenomena (such as wrist pulse and heartbeat), as well as improving resolution and sensitivity (voice letter recognition and speech recognition), with an ultra-low pressure limit and fast response. At a pressure of 265 kPa, the response time is 0.152 ms, and it has an extremely low pressure detection limit of 1.6 mPa, capable of detecting pulse and heartbeat beats, detecting the vibration of tuning forks at different frequencies and performing speech recognition, generating an open-circuit voltage of about 2V and a DC current of 100 μA through simple compression, and being able to stably output.

[0012] The technical solution adopted by the present invention to solve the above second technical problem is as follows: A preparation method of the above compression-type DC triboelectric sensor, characterized by including the following steps:

[0013] 1. Spread particulate dielectric material over one of the metal electrodes to form a dielectric material layer;

[0014] 2. Adhere the other metal electrode to the dielectric material layer to form a main body, and then encapsulate the main body with an insulating member to make the compression-type DC triboelectric sensor.

[0015] The technical solution adopted by the present invention to solve the above second technical problem is as follows: A preparation method of the above compression-type DC triboelectric sensor, characterized by including the following steps:

[0016] (1) Prepare a graphene oxide suspension:

[0017] (2) Coat the graphene oxide suspension prepared in step (1) on one of the metal electrodes and dry it to obtain a graphene oxide film, and a reduced graphene oxide film is also formed between the graphene oxide film and the metal electrode;

[0018] Alternatively, coat the graphene oxide suspension prepared in step (1) on the oil-proof paper, dry it to obtain a graphene oxide film, then tear off the oil-proof paper, and dry the graphene oxide film in an oven at 180 °C for 1 hour to form a reduced graphene oxide film, and attach one of the metal electrodes;

[0019] (3) Cover the graphene oxide film or reduced graphene oxide film obtained in step (2) with granular dielectric materials to form a dielectric material layer;

[0020] (4) Adhere another metal electrode (Al) to the dielectric material layer to form a main body, and then encapsulate the main body in an insulating part, thus obtaining the compression-type DC triboelectric sensor.

[0021] Preferably, in step (1), the suspended graphene sheets have a single-atom layer thickness, the thickness is between 0.5 and 1.0 nm, and the diameter of the sheet size is 1 to 50 μm.

[0022] Preferably, in step (1), the concentration of the graphene oxide suspension is 1 to 6 mg / mL.

[0023] In the above solution, in step (1), the graphene oxide suspension is prepared by an oxidative exfoliation method of graphite.

[0024] In step (2), the graphene oxide suspension is coated on the metal electrode by a drop-coating method, a suction filtration method or a spin-coating method. The drop-coating method is to drop the graphene oxide suspension on the metal electrode substrate; the spin-coating method is to smear the graphene oxide suspension on the rotating metal electrode so that the graphene oxide suspension is evenly dispersed on the surface of the metal electrode.

[0025] In step (2), the drying process is: drying for 1 to 24 h under the condition that the temperature is 50 to 70 °C.

[0026] The technical solution adopted by the present invention to solve the above third technical problem is: an application of the above compression-type DC triboelectric sensor, characterized in that it can be used for detecting human physiological signals, DC self-power supply and voice recognition.

[0027] Compared with the prior art, the advantages of the present invention are as follows: The compression-type DC triboelectric sensor of the present invention has a sandwich structure, and an interfacial Schottky barrier is formed through layer-by-layer assembly, which greatly inhibits the charge loss caused by electrostatic breakdown, realizes rapid response to static pressure and dynamic pressure, has an extremely low pressure detection limit, can detect pulse and heartbeat, detect the vibration of tuning forks with different frequencies and perform speech recognition, can generate open-circuit voltage and DC current through simple compression, and can stably output.

[0028] In addition, the preparation method of the present invention is simple and easy to operate. The prepared device can simultaneously detect static pressure and dynamic pressure, can be self-powered, has high sensitivity, fast response to pressure, and has good application prospects in the fields of biomedicine, health management, and speech recognition. Brief Description of the Drawings

[0029] Figure 1 is a schematic diagram of a physical photo of the compression-type DC triboelectric sensor prepared in Example 1 of the present invention;

[0030] Figure 2 is a schematic diagram of the cross-sectional morphology of the graphene oxide / reduced graphene oxide characterized by scanning electron microscopy prepared in Example 1 of the present invention;

[0031] Figure 3 is a schematic diagram of the morphology of graphene oxide prepared in Example 1 of the present invention by SEM-eds;

[0032] Figure 4 is a schematic diagram of the morphology of reduced graphene oxide prepared in Example 1 of the present invention by SEM-eds;

[0033] Figure 5 is the Tauc diagram of the ultraviolet-visible absorption spectrum of graphene oxide prepared in Example 1 of the present invention;

[0034] Figure 6 is the Tauc diagram of the ultraviolet-visible absorption spectrum of reduced graphene oxide prepared in Example 1 of the present invention;

[0035] Figure 7 is the ultraviolet photoelectron spectroscopy diagram of the graphene oxide film prepared in Example 1 of the present invention;

[0036] Figure 8 is the ultraviolet photoelectron spectroscopy diagram of the reduced graphene oxide film prepared in Example 1 of the present invention;

[0037] Figure 9 is the current-voltage curve of the compression-type DC triboelectric sensors of Al / Al2O3 / GO / rGO prepared in Example 1 of the present invention, Al / Al2O3 / rGO prepared in Example 2, and Al / Al2O3 / Al prepared in Example 3;

[0038] Figure 10 It is a comparison data graph of the current output of the compressive DC triboelectric sensor of Al / Al2O3 / GO / rGO prepared in Example 1 of the present invention, Al / Al2O3 / rGO prepared in Example 2, and Al / Al2O3 / Al prepared in Example 3 under the same pressure (265 kPa);

[0039] Figure 11 It is a data graph of the voltage response of the compressive DC triboelectric sensor prepared in Example 1 of the present invention under different pressures;

[0040] Figure 12 It is a response data graph of the compressive DC triboelectric sensor prepared in Example 1 of the present invention under a pressure of 265 kPa;

[0041] Figure 13 It is a data graph of the current response of the compressive DC triboelectric sensor prepared in Example 1 of the present invention under different pressures;

[0042] Figure 14 It is a cyclic stability data graph of the compressive DC triboelectric sensor prepared in Example 1 of the present invention under a pressure of 80 kPa;

[0043] Figure 15 It is a data graph of the compressive DC triboelectric sensor prepared in Example 1 of the present invention for detecting pulse;

[0044] Figure 16 It is a data graph of the compressive DC triboelectric sensor prepared in Example 1 of the present invention for detecting the heartbeat at different frequencies without breathing;

[0045] Figure 17 It is a data graph of the compressive DC triboelectric sensor prepared in Example 1 of the present invention for detecting the heartbeat during breathing;

[0046] Figure 18 It is a data graph of the response of the compressive DC triboelectric sensor prepared in Example 1 of the present invention when the experimenter says the letter "N";

[0047] Figure 19 It is a data graph of the response of the compressive DC triboelectric sensor prepared in Example 1 of the present invention when the experimenter says the letter "B";

[0048] Figure 20 It is a data graph of the response of the compressive DC triboelectric sensor prepared in Example 1 of the present invention when the experimenter says the letter "U";

[0049] Figure 21 It is a data graph of the response of the compressive DC triboelectric sensor prepared in Example 1 of the present invention when the experimenter says the letters "NBU";

[0050] Figure 22 It is a data graph of the response of the compression-type DC triboelectric sensor prepared in Example 1 of the present invention to a 256 Hz tuning fork;

[0051] Figure 23 It is a data graph of the response of the compression-type DC triboelectric sensor prepared in Example 1 of the present invention to a mobile phone ringtone;

[0052] Figure 24 It is a data graph of the current response of the compression-type DC triboelectric sensor prepared in Example 2 of the present invention under different pressures;

[0053] Figure 25 It is a data graph of the current response of the compression-type DC triboelectric sensor prepared in Example 3 of the present invention under different pressures;

[0054] Figure 26 It is a data graph of the current response of the compression-type DC triboelectric sensor prepared in Example 4 of the present invention under different pressures;

[0055] Figure 27 It is a data graph of the current response of the compression-type DC triboelectric sensor prepared in Example 5 of the present invention under different pressures;

[0056] Figure 28 It is a data graph of the current response of the compression-type DC triboelectric sensor prepared in Example 6 of the present invention under different pressures. Detailed implementation manners

[0057] The various exemplary implementation manners of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, characteristics, and implementation schemes of the present invention.

[0058] For the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0059] Example 1

[0060] The compression-type DC triboelectric sensor of this example includes a main body and an insulating member encapsulating the main body. The insulating member is made of polyimide. The main body includes two metal electrodes arranged oppositely and a dielectric material layer located between the two metal electrodes. The dielectric material layer is formed by laying granular dielectric material between the two metal electrodes. There are also graphene oxide film and reduced graphene oxide film between the metal electrodes and the dielectric material layer.

[0061] One of the metal electrodes is made of copper, and the other metal electrode is made of aluminum. The dielectric material is aluminum oxide particles.

[0062] The preparation method of the compression-type DC triboelectric sensor in this embodiment includes the following steps:

[0063] (1) Prepare a graphene oxide suspension: The graphene oxide suspension is prepared by the method of oxidative exfoliation of graphite, with a concentration of 5 mg / mL. The method of oxidative exfoliation of graphite is a prior art and is disclosed, for example, in the paper J. Am. Chem. Soc. 1958, 80, 1339, and will not be elaborated here.

[0064] The finally prepared suspended graphene sheets have a single-atom layer thickness of about 0.5 - 1.0 nm, and the sheet size diameter is 1 - 50 μm.

[0065] (2) Coat the graphene oxide suspension prepared in step (1) on one of the metal electrodes by the drop-casting method and dry it to obtain a graphene oxide film. Due to the reduction effect of the metal electrode, a layer of reduced graphene oxide film is also formed between the graphene oxide film and the metal electrode;

[0066] In this step, the metal electrode is a copper electrode. 0.5 mL of the graphene oxide suspension with a concentration of 5 mg / mL prepared in step (1) is dropped on the copper electrode and dried in an oven at 60 °C for 12 h to obtain an independent graphene oxide / reduced graphene oxide / reduced graphene oxide film. The thickness of the obtained graphene oxide / reduced graphene oxide film is about 10 μm;

[0067] (3) Cover the graphene oxide of the graphene oxide / reduced graphene oxide film prepared in step (2) with granular dielectric material to form a dielectric material layer;

[0068] (4) Adhere the other metal electrode (Al) to the dielectric material layer to form a main body, and then encapsulate the main body in an insulating part, thus obtaining the compression-type DC triboelectric sensor.

[0069] Characterization and performance test experiments of the graphene oxide / reduced graphene oxide film and the sensor prepared in this embodiment:

[0070] 1. Characterization by scanning electron microscopy (SEM), ultraviolet-visible absorption spectra (UV-Vis absorption spectra) and ultraviolet photoelectron spectroscopy (UPS):

[0071] The graphene oxide / reduced graphene oxide film prepared in Example 1 was characterized by SEM. The SEM detection was carried out using Hitachi, S-4800.

[0072] Among them, the physical photo morphology diagram of the compression-type DC triboelectric sensor is as Figure 1 shown.

[0073] The SEM electron microscope photo is as Figure 2 shown, Figure 2 which is a schematic cross-sectional morphology diagram of the scanning electron microscope characterization of the graphene oxide / reduced graphene oxide film prepared by the method of this embodiment, and the thickness is about 10 μm.

[0074] Figure 3 is a schematic diagram of the surface morphology and element ratio of the SEM-eds of the graphene oxide prepared in this embodiment, and the ratio of C:O is about 1.5:1.

[0075] Figure 4 is a schematic diagram of the surface morphology and element ratio of the SEM-eds of the reduced graphene oxide prepared in this embodiment, and the ratio of C:O is about 4:1.

[0076] Figure 5 is the Tauc diagram of the ultraviolet-visible absorption spectrum of the graphene oxide prepared in this embodiment. By calculating, the band gap of the graphene oxide is about 2.06 eV.

[0077] Figure 6 is the Tauc diagram of the ultraviolet-visible absorption spectrum of the reduced graphene oxide prepared in this embodiment. By calculating, the band gap of the graphene oxide is about 1.82 eV.

[0078] Figure 7 , 8 are the ultraviolet photoelectron spectroscopy characterizations of the graphene oxide / reduced graphene oxide film of this embodiment, respectively calculating its work function and valence band. The work function of the graphene oxide is 5 eV, and the valence band is 0.83 eV; the work function of the reduced graphene oxide is 4.7 eV, and the valence band is 1.73 eV. Through ultraviolet absorption and ultraviolet photoelectron spectroscopy, the energy level structure of Al / Al2O3 / GO / rGO is obtained, which has two-level Schottky energy barriers.

[0079] 2. Electrical analysis of the current-voltage curve:

[0080] Figure 9 are the current-voltage curves of Al / Al2O3 / Al, Al / Al2O3 / rGO, and Al / Al2O3 / GO / rGO. The Schottky barrier formed by Al-rGO-GO / rGO gradually has rectifying characteristics, which is beneficial to the collection of triboelectric charges.

[0081] 3. Performance test of compression-type DC triboelectric sensors with different structures under the same pressure:

[0082] Figure 10It is the current output of Al / Al2O3 / Al, Al / Al2O3 / rGO and Al / Al2O3 / GO / rGO under the same pressure conditions. Due to the existence of two Schottky barriers at the interface of the Al / Al2O3 / GO / rGO structure, the loss of friction charge is effectively suppressed, and the output DC current is increased by more than 6300 times.

[0083] 4. Performance test of Al / Al2O3 / GO / rGO compressed DC triboelectric sensor:

[0084] Figure 11 This is a response data diagram of the compressed DC triboelectric sensor prepared in this embodiment under different pressures. The pressure response range is 1.6mPa-265kPa, with an extremely low pressure limit, and can be used to detect tiny pressures, such as sound.

[0085] Figure 12 This is a voltage response data graph of the compressed DC triboelectric sensor prepared in this embodiment under a pressure of 265 kPa, which has a fast response of 0.152 ms and a voltage close to 2 V, allowing it to quickly identify changes in pressure.

[0086] Figure 13 This is a current response data diagram of the compressed DC triboelectric sensor prepared in this embodiment under different pressures. It can generate a DC current of 100 μA, which is beneficial for applications in the fields of DC power generation.

[0087] Figure 14 This is a cyclic stability data graph of the compressed DC triboelectric sensor prepared in this embodiment, which can withstand 8200 pressure cycles and has good stability.

[0088] 5. Application of Al / Al2O3 / GO / rGO compression DC triboelectric sensor:

[0089] Figure 15 This is a data graph of the pulse detected by the compressed DC triboelectric sensor prepared in this embodiment. The device is attached to the wrist pulse and can identify the three characteristic peaks of the pulse with high resolution.

[0090] Figure 16 This is a data graph of the compressed DC triboelectric sensor prepared in this embodiment detecting heartbeats of different frequencies without breathing.

[0091] Figure 17 This is a data graph of the compressed DC triboelectric sensor prepared in this embodiment detecting breathing and heartbeat, which can detect the human heartbeat signal and different frequencies through the skin.

[0092] Figure 18It is a data graph of the response of the compression-type DC triboelectric sensor prepared in this embodiment to the voice letter "N".

[0093] Figure 19 It is a data graph of the response of the compression-type DC triboelectric sensor prepared in this embodiment to the voice letter "B".

[0094] Figure 20 It is a data graph of the response of the compression-type DC triboelectric sensor prepared in this embodiment to the voice letter "U".

[0095] Figure 21 It is a data graph of the response of the compression-type DC triboelectric sensor prepared in this embodiment to the voice letters "NBU". When the tester speaks to the device, the airflow differences for different letters of human speech are also well recognized and distinguished.

[0096] Figure 22 It is a data graph of the response of the compression-type DC triboelectric sensor prepared in this embodiment to a 256 Hz tuning fork. The device can also recognize the vibration of the tuning fork in the air at different frequencies.

[0097] Figure 23 It is a data graph of the response of the compression-type DC triboelectric sensor prepared in this embodiment to the ringtone of a mobile phone. When the mobile phone is not playing and is close to the device, there is no response. When we play music beside it, it can recognize it.

[0098] The above-mentioned human pulse / heartbeat detection is to attach the compression-type DC triboelectric sensor to the wrist and the epidermis of the heart, and perform large-scale DC self-power supply through the series connection of the compression-type DC triboelectric sensors. At a certain distance from the compression-type DC triboelectric sensor, speaking to it realizes voice recognition.

[0099] Example 2

[0100] The difference between this embodiment and Embodiment 1 is that step (2) is different, and the others are the same as Embodiment 1.

[0101] The preparation method of the compression-type DC triboelectric sensor in this embodiment includes the following steps:

[0102] (1) Prepare graphene oxide suspension: The graphene oxide suspension is prepared by the method of oxidative exfoliation of graphite, with a concentration of 5 mg / mL. The method of oxidative exfoliation of graphite is a prior art and is disclosed, for example, in the paper J. Am. Chem. Soc. 1958, 80, 1339, and will not be elaborated here.

[0103] The finally prepared suspended graphene sheets are of single atomic layer thickness, about 0.5 - 1.0 nm, and the sheet size diameter is 1 - 50 μm.

[0104] (2) Coat the graphene oxide suspension prepared in step (1) on oil-repellent paper, dry it to obtain a graphene oxide film, then tear off the oil-repellent paper, and place the graphene oxide film in an oven at 180 °C for 1 hour to dry to form a reduced graphene oxide film, and attach one of the metal electrodes.

[0105] In this step, the metal electrode is a copper electrode. Drop 0.5 mL of the graphene oxide suspension with a concentration of 5 mg / mL prepared in step (1) on the copper electrode, and dry it in an oven at 60 °C for 12 h to obtain an independent reduced graphene oxide film. The thickness of the obtained reduced graphene oxide film is about 10 μm.

[0106] (3) Cover the reduced graphene oxide film prepared in step (2) with granular dielectric material to form a dielectric material layer.

[0107] (4) Attach another metal electrode (Al) to the dielectric material layer to form a main body, and then encapsulate the main body in an insulating part, thus obtaining a compressive DC triboelectric sensor.

[0108] This embodiment is mainly to verify the effect brought by the Schottky barrier formed by the reduced graphene oxide as the electrode. Through experimental verification, the compressive DC triboelectric sensor prepared by the preparation method of Example 1 has better performance than that of Example 2.

[0109] Example 3

[0110] The compressive DC triboelectric sensor of this embodiment includes a main body and an insulating part for encapsulating the main body. The main body includes two relatively arranged metal electrodes and a dielectric material layer located between the two metal electrodes. The dielectric material layer is formed by spreading granular dielectric material between the two metal electrodes. The dielectric material is Al2O3 particles. The material of one of the metal electrodes is aluminum, and of course, it can also be copper, gold, silver, or platinum; the material of the other metal electrode is aluminum.

[0111] The preparation method of the compressive DC triboelectric sensor of this embodiment includes the following steps:

[0112] I. Spread the granular dielectric material on one of the metal electrodes (Al) to form a dielectric material layer.

[0113] II. Attach the other metal electrode (Al) to the dielectric material layer to form a main body, and then encapsulate the main body with an insulating part, thus making a compressive DC triboelectric sensor.

[0114] Example 4

[0115] The difference between this embodiment and Example 3 is that the granular dielectric material is spread on Cu, and the others are the same as Example 3, that is, one of the metal electrodes is Al and the other metal electrode is Cu.

[0116] Example 5

[0117] The difference between this example and Example 4 is that the dielectric material is silicon dioxide particles, and the others are the same as in Example 4.

[0118] Example 6

[0119] The difference between this example and Example 4 is that the dielectric material is soil particles, and the others are the same as in Example 4.

[0120] Through Figure 5 , the material characterizations of 6, 7, and 8 show that for the work functions of Al, GO, and rGO, the work function of Al is 4.28 eV, that of GO is 5 eV, and that of rGO is 4.7 eV. The Al / Al2O3 / GO / rGO structure will gradually form Schottky barriers. From Figure 9 the current-voltage curves, it can be seen that for the structure of Example 3: Al / Al2O3 / Al, it has a certain interfacial Schottky barrier; when rGO is used to replace Al to form the structure of Example 2: Al / Al2O3 / rGO, the barrier is enhanced; further adding a layer of GO inside to form the structure of Example 1: Al / Al2O3 / GO / rGO, it has an obvious rectifying Schottky barrier. Therefore, due to the presence of two Schottky barriers at the interface of the structure of Example 1 (Al / Al2O3 / GO / rGO), the rectifying effect is enhanced, which can effectively suppress the loss of frictional charges and greatly improve the output DC current. Figure 24 is the current response data graph of the compression-type DC triboelectric sensor prepared in Example 2 of the present invention under different pressures. It can be seen that at a pressure of 265 kPa, the DC output current is about 50 μA; Figure 25 is the current response data graph of the compression-type DC triboelectric sensor prepared in Example 3 of the present invention under different pressures. Its DC output current is about 16 nA; Figure 26 is the current response data graph of the compression-type DC triboelectric sensor prepared in Example 4 of the present invention under different pressures. Its DC output current is about 1 μA; Figure 27 is the current response data graph of the compression-type DC triboelectric sensor prepared in Example 5 of the present invention under different pressures. Its DC output current is about 500 nA; Figure 28It is the current response data graph of the compression-type DC triboelectric sensor prepared in Example 6 of the present invention under different pressures, and its DC output current is about 50 nA. The performance of the device in Example 1 is more than 6,300 times higher than that of the device in Example 3 and about twice that of the device in Example 2, indicating that the existence of the two Schottky barriers at the interface of the structure in Example 1 (Al / Al2O3 / GO / rGO) effectively inhibits the loss of triboelectric charges and greatly increases the DC current. The performance of the device in Example 4 is 200 times and 2,000 times higher than that in Examples 5 and 6, respectively.

[0121] In summary, the sensor prepared by the present invention can detect static and high-frequency dynamic forces, physiological signals and acoustic phenomena, such as wrist pulse and heartbeat, and improve the resolution and sensitivity to recognize speech letters, expanding the application of wearable, high-performance DC triboelectric sensors in the Internet of Things system, bringing great prospects, especially in healthcare, personalized monitoring and speech recognition.

Claims

1. A compression-type DC triboelectric sensor, characterized in that, It includes a main body and an insulating member encapsulating the main body. The main body includes two oppositely arranged metal electrodes and a dielectric material layer located between the two metal electrodes. The dielectric material layer is formed by laying granular dielectric material between the two metal electrodes.

2. The compressive DC triboelectric sensor according to claim 1, characterized in that: The material of one of the metal electrodes is copper, gold, silver, platinum or aluminum; the material of the other metal electrode is aluminum.

3. The compression-type DC triboelectric sensor according to claim 1, wherein: The dielectric material is aluminum oxide particles, soil particles or silicon dioxide particles.

4. The compressive DC triboelectric sensor according to any one of claims 1 to 3, characterized in that: The main body further includes a graphene oxide film and / or a reduced graphene oxide film located between the metal electrode and the dielectric material layer.

5. A method for preparing the compression-type DC triboelectric sensor according to any one of claims 1 to 3, characterized in that, It includes the following steps:

1. Cover one of the metal electrodes with granular dielectric material to form a dielectric material layer.

2. Adhere the other metal electrode to the dielectric material layer to form a main body, and then encapsulate the main body with an insulating member, thus manufacturing the compression type DC triboelectric sensor.

6. A method for preparing the compression-type DC triboelectric sensor according to claim 4, characterized in that, It includes the following steps: (1) Prepare a graphene oxide suspension: (2) Coat the graphene oxide suspension prepared in step (1) on one of the metal electrodes and dry it to obtain a graphene oxide film. There is also a layer of reduced graphene oxide film formed between the graphene oxide film and the metal electrode. Or, coat the graphene oxide suspension prepared in step (1) on oil-proof paper, dry it to obtain a graphene oxide film, then tear off the oil-proof paper, place the graphene oxide film in an oven to dry to form a reduced graphene oxide film, and then attach one of the metal electrodes. (3) Cover the graphene oxide film or reduced graphene oxide film obtained in step (2) with granular dielectric material to form a dielectric material layer. (4) Adhere the other metal electrode to the dielectric material layer to form a main body, and then encapsulate the main body in an insulating member, thus manufacturing the compression type DC triboelectric sensor.

7. The preparation method according to claim 6, characterized in that: In step (1), the suspended graphene sheet layer has a single-atom layer thickness, with a thickness between 0.5 and 1.0 nm and a sheet size diameter of 1 to 50 μm.

8. The preparation method according to claim 6, characterized in that: In step (1), the concentration of the graphene oxide suspension is 1 to 6 mg / mL.

9. The preparation method according to claim 6, wherein: In step (1), the graphene oxide suspension is prepared by an oxidative exfoliation method of graphite.

10. Application of the compression-type DC triboelectric sensor according to any one of claims 1 to 4, characterized in that It can be used for detecting human physiological signals, DC self-power supply and voice recognition.

Images