CN115560886A - Passive pressure sensor based on piezoelectric potential enhanced triboelectric effect and preparation method thereof - Google Patents
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- G01L1/00—Measuring force or stress, in general
- G01L1/16—Measuring force or stress, in general using properties of piezoelectric devices
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Abstract
The invention discloses a passive pressure sensor based on piezoelectric potential enhanced triboelectric effect, which comprises: the flexible high polymer material layer is arranged on the electrode layer; the thickness of ZnO deposited when the ZnO wrinkled layer is manufactured is 10 nm-1 mu m, the thermal expansion coefficients of the flexible high polymer material for manufacturing the flexible high polymer material layer and the ZnO are not matched, and the top crystal face of the ZnO in the ZnO nanowire layer is a (0001) crystal face. The pressure sensor provided by the invention has higher sensitivity.
Description
Technical Field
The invention belongs to the field of pressure sensors, and particularly relates to a passive pressure sensor based on piezoelectric potential enhanced triboelectric effect and a preparation method thereof.
Background
In recent years, with the rapid development of the internet of things (IoT) and Artificial Intelligence (AI), pressure sensing electronics with precise mechanical sensing capabilities have drawn more and more attention in the fields of human-machine interface systems, artificial skin and prosthetics, and robotics. Although various pressure sensors based on transistor, piezoresistive and capacitive effects have been developed, these electronic devices rely heavily on external power sources, such as batteries and solar cells. Due to limited battery capacity and short life, solar cells are subject to environmental constraints, which inevitably affects the long-term stable operation of the pressure sensor.
In order to overcome the problem, the emerging technology of the triboelectric nano-generator (TENG) is widely used for developing a passive pressure sensing system capable of self-driving, and the TENG-based passive pressure sensor (TPS for short) has wide application prospect due to the advantages of excellent electromechanical response performance, simple structure, low cost, easiness in transplantation and the like.
In the prior art, the micro/nano structure is constructed on the surface of the friction layer to increase the surface charge density; for example, a surface structure, such as a monotonous micro-nano cone, a cylinder, a pyramid, a porous structure, or a fine hierarchical micro-nano structure, is introduced on the surface of the friction material, so that the sensitivity of the TPS can be improved by increasing the interface roughness and the stress concentration effect.
However, the sensitivity of the existing TPS is still low, which severely limits its wide application in the fields of human interface systems, artificial skin and prosthetics.
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides a passive pressure sensor based on piezoelectric potential enhanced triboelectric effect and a preparation method thereof.
The technical problem to be solved by the invention is realized by the following technical scheme:
a passive pressure sensor based on piezoelectric potential enhanced triboelectric effect, comprising:
an electrode layer;
a flexible polymer material layer; the flexible high polymer material layer is positioned on the electrode layer;
a ZnO wrinkled layer; the ZnO wrinkled layer is positioned on the flexible high polymer material layer;
a ZnO nanowire layer; the ZnO nanowire layer is positioned on the ZnO wrinkle layer;
a negative friction layer; the negative friction layer is positioned above the ZnO nanowire layer;
the thickness of ZnO deposited when the ZnO wrinkled layer is manufactured is 10 nm-1 mu m, the thermal expansion coefficients of the flexible high polymer material for manufacturing the flexible high polymer material layer and the ZnO are not matched, and the top crystal face of the ZnO in the ZnO nanowire layer is a (0001) crystal face.
Optionally, the method further comprises: a spacer;
the spacer is positioned between the negative friction layer and the ZnO nanowire layer, and the occupied area of the spacer is smaller than that of the ZnO nanowire layer.
Optionally, the flexible polymer material includes: polydimethylsiloxane PDMS.
Optionally, the material of the negative friction layer includes: fluorinated ethylene propylene copolymer FEP.
Optionally, the electrode layer comprises: a substrate and a conductive layer over the substrate;
the material of the conducting layer includes: indium Tin Oxide (ITO);
the material of the substrate comprises: polyethylene terephthalate PET.
The invention also provides a preparation method of the passive pressure sensor based on the piezoelectric potential enhanced triboelectric effect, which comprises the following steps:
coating a flexible high polymer material on the electrode layer in a spinning mode to form a flexible high polymer material layer; the thermal expansion coefficients of the flexible high polymer material layer and ZnO are not matched;
depositing a layer of ZnO with the thickness of 10 nm-1 mu m on the flexible polymer material layer, and then cooling to form a ZnO wrinkle layer on the flexible polymer material layer;
growing ZnO nanowires on the ZnO wrinkled layer to form a ZnO nanowire layer;
sticking a negative friction layer on the ZnO nanowire layer to obtain a passive pressure sensor based on the piezoelectric potential enhanced triboelectric effect;
and the top crystal face of ZnO in the ZnO nanowire layer is a (0001) crystal face.
Optionally, the method further comprises:
before the negative friction layer is pasted on the ZnO nanowire layer, a spacer is placed on the ZnO nanowire layer, and the occupied area of the spacer is smaller than that of the ZnO nanowire layer.
Optionally, depositing a layer of ZnO with a thickness of 10nm to 1 μm on the flexible polymer material layer, including:
and depositing a layer of ZnO with the thickness of 10 nm-1 mu m on the flexible polymer material layer by adopting a magnetron sputtering process.
Optionally, growing ZnO nanowires on the ZnO wrinkled layer, comprising:
and growing the ZnO nanowire on the ZnO wrinkled layer by adopting a room-temperature hydrothermal method.
Optionally, the height of the ZnO nanowires in the ZnO nanowire layer is 10nm to 50 μm.
According to the passive pressure sensor based on the piezoelectric potential enhanced triboelectric effect, the layered fold structure formed by the ZnO fold layer and the ZnO nanowire layer is arranged, the layered fold structure with the piezoelectric effect can generate a macroscopic piezoelectric potential under the action of external pressure, and the barrier height (electric effect) of an interface between the layered fold structure and a negative friction layer is effectively regulated and controlled, so that the separation of frictional charges is effectively promoted, the surface frictional charge density is improved, the electric effect enhancement strategy is matched with the negative friction layer for use, the pressure detection sensitivity of the TPS can be well improved, and the TPS can be widely applied to the fields of human-computer interface systems, artificial skins, artificial limbs and the like.
The present invention will be described in further detail with reference to the accompanying drawings.
Drawings
Fig. 1 (a) is a schematic cross-sectional structure diagram of a passive pressure sensor based on piezoelectric potential enhanced triboelectric effect according to an embodiment of the present invention;
FIG. 1 (b) is a perspective view of the passive pressure sensor shown in FIG. 1 (a);
FIG. 2 is a schematic diagram of a passive pressure sensor based on piezoelectric potential enhanced triboelectric effect provided by an embodiment of the invention;
FIG. 3 is a schematic diagram of the working principle of a passive pressure sensor based on piezoelectric potential enhanced triboelectric effect according to an embodiment of the present invention;
FIG. 4 is a schematic diagram of an operating mechanism of a passive pressure sensor based on piezoelectric potential enhanced triboelectric effect according to an embodiment of the present invention;
FIG. 5 is a schematic structural diagram of another passive pressure sensor based on piezoelectric potential enhanced triboelectric effect according to an embodiment of the present invention;
fig. 6 and 7 respectively show experimental results of experiment 1 developed to verify the advantageous effects of the passive pressure sensor provided by the embodiment of the present invention;
fig. 8 (a) -8 (d) show experimental results of experiment 2, respectively, developed to verify the beneficial effects of the passive pressure sensor provided by the embodiment of the present invention;
FIG. 9 is a flowchart of a method for manufacturing a passive pressure sensor based on piezoelectric potential enhanced triboelectric effect according to an embodiment of the present invention;
FIG. 10 is a flow chart of a graphical representation of the method shown in FIG. 9;
fig. 11 (a) to 11 (c) respectively show scanning electron micrographs of the respective layer structures prepared in the method shown in fig. 9.
Detailed Description
The present invention will be described in further detail with reference to specific examples, but the embodiments of the present invention are not limited thereto.
In order to further improve the sensitivity of the TPS, an embodiment of the present invention provides a passive pressure sensor based on a piezoelectric potential enhanced triboelectric effect, as shown in fig. 1 (a), the pressure sensor includes: the flexible high polymer material layer is arranged on the surface of the substrate and comprises an electrode layer, a flexible high polymer material layer, a ZnO wrinkle layer, a ZnO nanowire layer and a negative friction layer.
Fig. 1 (b) shows a perspective view of the passive pressure sensor in fig. 1 (a), and as can be seen from fig. 1 (a) and fig. 1 (b), the passive pressure sensor based on piezoelectric potential enhanced triboelectric effect provided by the embodiment of the present invention is a TPS of a single electrode operation mode.
Wherein, the electrode layer includes: a substrate and a conductive layer on the substrate. The material of the conductive layer may include: ITO (indium tin oxide), or may be a common metal electrode material such as copper, aluminum, and the like. The thickness of the electrode layer is 30 μm to 1mm, for example 50 μm. The material of the substrate may include: PET (polyethylene terephthalate); or other rigid substrates such as silicon wafers, glass, polystyrene, etc.
The flexible high polymer material layer is positioned on the electrode layer; the flexible polymer material for making the flexible polymer material layer may include PDMS (polydimethylsiloxane), PU (polyurethane), ecoflex (copolyester), etc., and any flexible polymer material with a thermal expansion coefficient not matched with that of ZnO may be used to make the flexible polymer material layer. The thickness of the flexible polymer material layer is 1 μm to 3mm, for example, 50 μm.
The ZnO wrinkled layer is positioned on the flexible high polymer material layer, and the thickness of ZnO deposited when the ZnO wrinkled layer is prepared is 10 nm-1 μm.
The inventor finds through experiments that the thickness of the deposited ZnO is less than 10nm, the wrinkle is not formed enough, and when the thickness of the deposited ZnO is more than 1 μm, the better local shrinkage effect can not be achieved due to the excessive thickness of the ZnO, so the wrinkle is not obvious enough. Therefore, depositing ZnO of 10nm to 1 μm can produce better ZnO wrinkled layers.
The ZnO nanowire layer is positioned on the ZnO wrinkle layer; the height of the ZnO nanowire is 10 nm-50 mu m.
In the embodiment of the invention, the ZnO wrinkled layer simulates the wrinkles of human fingers and can sense external mechanical stimulation with high precision, so that the ZnO layered wrinkled structure formed after the ZnO nanowire layer is grown by taking the wrinkled structure as a seed layer has higher sensing sensitivity to the external mechanical stimulation.
In the embodiment of the invention, znO is a wurtzite ZnO material, and the top crystal plane of ZnO in the ZnO nanowire layer is a (0001) crystal plane.
The negative friction layer is positioned on the ZnO nanowire layer; the negative friction layer may be made of: FEP (fluorinated ethylene propylene copolymer), PTFE (fluorinated ethylene propylene copolymer), PI (polyimide), PET (polyethylene terephthalate), or the like. The thickness of the negative friction layer is 1-300 μm.
In practical applications, an external pressure is applied to the pressure sensor through the negative friction layer (as shown in fig. 2), and the electrode layer of the pressure sensor outputs the pressure sensed by the pressure sensor in the form of an electrical signal.
The working mechanism of the passive pressure sensor based on the piezoelectric potential enhanced triboelectric effect provided by the embodiment of the invention is as follows:
as shown in fig. 3, the ZnO layered pleat structure is in contact with a negative friction layer (represented by FEP in fig. 3). According to the triboelectric sequence, electrons are transferred from the ZnO to the negative-polarity rubbing layer, leaving an equal number of positive charges on top of the ZnO layered wrinkle structure, as shown in sub-diagram I in fig. 3. Due to the layered corrugated structure, only a small amount of ZnO nanowires was initially in contact with the negative friction layer. Thus, all pressure is concentrated in a small area, thereby providing the TPS with high sensitivity. When the layered wrinkled structure of ZnO is compressed, a piezoelectric potential is generated along the length direction of the ZnO nanowire, so that the triboelectric effect between the negative friction layer and the ZnO is enhanced, as shown in sub-diagram II in fig. 3. When a higher external force is applied to the ZnO layered corrugated structure, large deformation and high voltage potential are achieved. Meanwhile, more ZnO nanowires located on different height wavy folds are in contact with the negative friction layer, and more electrons are transferred from ZnO to the negative friction layer, as shown in sub-diagram III in fig. 3. After the pressure was removed, the potential distribution between the negative friction layer and the ZnO was as shown in sub-graph IV in fig. 3.
More specifically, see the charge distribution and corresponding charge transfer process in the electron cloud potential well model shown in fig. 4: when the negative friction layer (represented by FEP in figure 4) rubs with the ZnO layered wrinkle structure, the contact electrification is carried outDuring the process, the piezoelectric potential generated by the deformation of the ZnO layered pleat structure will couple into the triboelectric charge separation process. Initially, the negative friction layer and ZnO are close to each other, but there is still a distance between them, hindering the transfer of triboelectric charges between them. When the negative friction layer is just contacted with ZnO, due to the shielding effect between the two materials in physical contact, the electron clouds are partially overlapped, and the initial single potential well is changed into an asymmetric double potential well. Electrons occupying specific atomic orbitals in ZnO tend to move to empty orbitals lower in the negative-polarity frictional layer, and the number of transferred electrons is proportional to the difference in the depth of potential well (surface potential difference) between the two materials. Then, when pressure is applied to the negative-polarity friction layer and the ZnO layered wrinkle structure, a pressure potential V is generated in a direction (denoted by 0001 in fig. 3) from the negative-polarity friction layer toward a crystal plane of ZnO piezo And the potential well of ZnO rises upward. As a result, more electrons will be transferred from the ZnO to the negative friction layer until a new equilibrium is reached.
Theoretically, based on the above working mechanism, the unique layered pleat structure in the present embodiment is effective in combination with the piezoelectric enhanced triboelectric effect to improve the sensitivity and extend the working range of the TPS.
According to the passive pressure sensor based on the piezoelectric potential enhanced triboelectric effect, the layered fold structure formed by the ZnO fold layer and the ZnO nanowire layer is arranged, the layered fold structure with the piezoelectric effect can generate a macroscopic piezoelectric potential under the action of external pressure, and the barrier height (electric effect) of an interface between the layered fold structure and a negative friction layer is effectively regulated and controlled, so that the separation of frictional charge is effectively promoted, and the surface frictional charge density is improved.
In an embodiment, as shown in fig. 5, a passive pressure sensor based on a piezoelectric potential enhanced triboelectric effect according to an embodiment of the present invention may further include: a spacer; the spacer is positioned between the negative friction layer and the ZnO nanowire layer, and the occupied area of the spacer is smaller than that of the ZnO nanowire layer.
It can be understood that the spacer acts to isolate the negative friction layer from the ZnO nanowire layer by a distance, thereby reducing the noise floor of the pressure sensor without the application of external pressure. Therefore, in practice, the occupied area of the spacer is far smaller than that of the ZnO nanowire layer, and a certain spacing effect is achieved.
In practical applications, the spacer may be a polyurethane foam, but is not limited thereto.
Preferably, the spacers can be respectively attached to four corners of the ZnO nanowire layer, and the height of the spacers is about 5 mm; of course, it is not limited thereto.
The advantageous effects of the embodiments of the present invention are explained below by experimental data.
Experiment 1: preparing TPS with an electrode layer of ITO film, a flexible polymer material layer of PDMS and a negative friction layer of FEP film, and placing a polyurethane foam spacer between the ZnO nanowire layer and the negative friction layer.
According to the non-centrosymmetric structure and piezoelectric property of the wurtzite ZnO material, the positive voltage potentials of the wurtzite ZnO material are respectively analyzed by a Kelvin probe force microscope
(the crystal face of ZnO is (0001) crystal face), negative voltage potential
(the crystal plane of ZnO is (000-1) crystal plane) and zero piezoelectric potential
(the crystal plane of ZnO is a (10-10) crystal plane), the surface potential of the FEP film at the time of rubbing against the layered wrinkle structure of ZnO changes.
Specifically, as shown in FIGS. 6 and 7, at negative voltage potential
In the case of (1), at different pressures (0 kPa, 10kPa, 20kPa, 1)00 kPa) against the surface of the ZnO layered pleat structure, the surface potential of the FEP film sharply decreases from-360 mV (0 kPa) to-6.34V (100 kPa). At zero voltage potential
In the case of (2), the surface potential of the FEP film was lowered only from-360 mV (0 Pa) to-4.84V (100 kPa), respectively. At a positive voltage potential
In the case of (2), the surface potentials of the FEP films were lowered from-360 mV (0 Pa) to-3.29V (100 kPa), respectively.
Wherein the negative voltage potential generated by the ZnO enhances the triboelectric effect between the FEP and ZnO, whereas the positive voltage potential is reduced, since a lower negative surface potential means that more electrons are captured from the ZnO by the FEP. Therefore, using negative voltage potential
Adjusting the triboelectric effect is an effective way to improve the sensitivity of TPS, especially in high pressure areas where the piezoelectric potential can be more efficiently regulated.
Experiment 2: referring to the TPS prepared in experiment 1, TPS having only a single ZnO wrinkled layer was prepared and the performance thereof was verified. The results of the experiment showed that the charge densities thereof were 5.56nC/cm at pressures of 10kPa, 20kPa and 100kPa, respectively 2 (nanocavity/square centimeter) and 6.15nC/cm 2 And 6.64nC/cm 2 . Comparing the performance of the TPS with the ZnO layered pleat structure in experiment 1, it can be seen that when the pressure is increased from 10kPa to 20kPa and 100kPa, the charge density of the TPS with the ZnO layered pleat structure is increased by 50.9% and 151%, respectively, 4.8 times and 7.8 times, respectively, of the TPS with the single ZnO pleat layer, which is significantly greater than that of the TPS with the single ZnO pleat layer, which proves the effective charge separation and transfer capability of the ZnO layered pleat structure in the embodiment of the present invention, and illustrates that the TPS with the ZnO layered pleat structure in the embodiment of the present invention has higher sensitivity.
Experiment 2: the TPS prepared in experiment 1 and experiment 2, respectively, was tested for sensitivity.
Specifically, the TPS sensitivity is calculated from the applied force/pressure and the output voltage measured from the electrode layer. As shown in fig. 8 (a), the pressure sensitivity of TPS can be divided into two regions: low pressure zones (< 25 kPa) and high pressure zones (25-476 kPa); wherein, the TPS with a single ZnO wrinkled layer has the pressure sensitivity K of only 1.06V/kPa and 0.06V/kPa in two areas. In contrast, the sensitivity K of TPS with layered fold structure in two areas is 4.14V/kPa and 0.25V/kPa, which are respectively improved by 2.91 times and 3 times compared with the former. It can be seen that the embodiments of the present invention hardly decrease the modulus of the sensing layer on the premise of effectively improving the sensitivity of the TPS, and thus show a good balance between high sensitivity and a wide detection range (up to 476 kPa).
The TPS with a layered pleat structure is shown in fig. 8 (b) as being able to generate an electrical response to external mechanical stimuli in real time, and the response time of the TPS is shown in fig. 8 (c), and it can be seen that the response time is only about 28 ms.
In addition, a plurality of existing TPS and TPS with a layered fold structure provided by the embodiment of the invention are selected, and the relation curve of pressure and sensitivity of the TPS and the TPS is analyzed; as shown in fig. 8 (d), it can be seen that the TPS with a layered wrinkle structure provided in the embodiment of the present invention has a significant advantage in terms of both sensitivity and detection range, which illustrates that the design concept of compatibility between the piezo-potential-enhanced triboelectric effect (electric effect) and the layered wrinkle structure (mechanical effect), and the combination of the electric effect and the mechanical effect in the embodiment of the present invention is very beneficial to improving the sensitivity of the TPS and endowing the TPS with a wider detection range.
Based on the same inventive concept, the embodiment of the present invention further provides a method for manufacturing the passive pressure sensor based on the piezoelectric potential enhanced triboelectric effect, as shown in fig. 9, the method includes the following steps:
s10: coating a flexible high polymer material on the electrode layer in a spinning mode to form a flexible high polymer material layer; the thermal expansion coefficients of the flexible high polymer material and ZnO of the flexible high polymer material layer are not matched.
For example, 10 parts by mass of PDMS prepolymer may be weighed, then 1 part by mass of curing agent may be added, stirred and mixed uniformly for 10 minutes, and subjected to ultrasound for 5min to remove air bubbles, so as to obtain a PDMS prepolymer solution (mass ratio of substrate to crosslinking curing agent is 10. Then, a PDMS film with a thickness of 50 μm was spin-coated on the ITO or PET film with a thickness of 50 μm by a spin coating method, and cured at 80 ℃ for 30 minutes to form a flexible polymer material layer.
Or weighing the A and B components of the ecoflex in equal mass, stirring for 5min until the components are fully and uniformly mixed, ultrasonically treating for 5min to remove bubbles, preparing an ecoflex film by spin coating, and curing for 20min at 80 ℃ to obtain the flexible polymer material layer.
Or, the polyurethane can be weighed and dissolved in DMF (N, N-dimethylformamide) (for example, 1g of PU and 3g of DMF), stirred for 30min until the polyurethane is completely dissolved, a PU film is prepared by spin coating, and the solvent is dried at 60 ℃ for 1h to obtain the flexible polymer material layer.
Fig. 10, diagram II, shows a schematic diagram of a flexible polymer material layer; fig. 11 (a) shows a scanning electron micrograph of the prepared flexible polymer material layer.
S20: depositing a layer of ZnO with the thickness of 10 nm-1 mu m on the flexible polymer material layer, and then cooling to form a ZnO wrinkled layer on the flexible polymer material layer.
Specifically, the step can adopt a magnetron sputtering process to deposit ZnO on the flexible high polymer material layer. The sputtering power may be 100W, and the gas pressure may be 0.5Pa, but is not limited thereto. And cooling after the sputtering of the ZnO is finished, wherein the cooling time can be calculated according to the thickness of the specific sputtered ZnO, and the cooling time can be estimated according to the thickness of 2nm per minute during specific calculation. After cooling is finished according to the estimated time, because the thermal expansion coefficients of the flexible high polymer material and the ZnO of the high polymer material layer are not matched, the top surface of the hybrid structure formed by the flexible high polymer material layer and the ZnO tends to shrink locally, and a wrinkle structure, namely a ZnO wrinkle layer, can be formed on the flexible high polymer material layer spontaneously.
Fig. 10, sub-diagram II, shows a schematic diagram of the preparation of the ZnO wrinkled layer, and sub-diagram III shows a schematic diagram of the prepared ZnO wrinkled layer; fig. 11 (b) shows a scanning electron micrograph of the ZnO wrinkle layer after preparation, and it can be seen that the ZnO wrinkles are in the micrometer scale.
S30: growing ZnO nanowires on the ZnO wrinkled layer to form a ZnO nanowire layer; the top crystal face of ZnO in the ZnO nanowire layer is a (0001) crystal face.
Specifically, a room-temperature hydrothermal method is adopted to grow the ZnO nanowire on the ZnO wrinkled layer.
Illustratively, 0.08g of NaOH and 0.0325g of ZnO can be dissolved in 40mL of deionized water and stirred continuously for 10 minutes to give a clear precursor solution. And then, completely immersing the grown flexible polymer material layer and the ZnO wrinkled layer into the solution, and growing the ZnO nanowire at room temperature. Then, the substrate was taken out and washed with deionized water, and dried at 65 ℃ for 30 minutes to form a ZnO nanowire layer.
A schematic diagram for preparing a ZnO nanowire layer is shown in sub-diagram IV in fig. 10; fig. 11 (c) shows a scanning electron micrograph after the ZnO nanowire layer is prepared, and it can be seen that the ZnO nanowires grow with the wrinkles prepared in step S20 as a seed layer, forming a special structure having two different levels of undulations, a micro level and a nano level.
S40: and sticking a negative friction layer on the ZnO nanowire layer to obtain the passive pressure sensor based on the piezoelectric potential enhanced triboelectric effect.
Optionally, in an implementation manner, the method for manufacturing a passive pressure sensor based on a piezoelectric potential enhanced triboelectric effect according to the embodiment of the present invention may further include:
before the negative friction layer is pasted on the ZnO nanowire layer, a spacer is placed on the ZnO nanowire layer, and the occupied area of the spacer is smaller than that of the ZnO nanowire layer.
Illustratively, polyurethane foam having a height of 5mm may be attached to four corners of the ZnO nanowire layer. The FEP film is then applied over the polyurethane foam.
The size of the passive pressure sensor is not limited, and the passive pressure sensor can be designed according to a use scene in practice.
It should be noted that, for the embodiment of the preparation method, since the dimensions and material parameters of the structures of the layers prepared by the embodiment of the passive pressure sensor have been described in detail in the embodiment of the passive pressure sensor, the description in the embodiment of the preparation method is relatively simple, and the relevant points can be referred to the description in the embodiment of the passive pressure sensor.
In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like, indicate orientations and positional relationships based on those shown in the drawings, and are used only for convenience of description and simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be considered as limiting the present invention.
In the present invention, unless expressly stated or limited otherwise, the recitation of a first feature "on" or "under" a second feature may include the recitation of the first and second features being in direct contact, and may also include the recitation that the first and second features are not in direct contact, but are in contact via another feature between them. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.
In the description of the specification, references to descriptions of the terms "one embodiment," "some embodiments," "an example," "a specific example," or "some examples" or the like are intended to mean that a particular feature or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples described in this specification can be combined and combined by those skilled in the art.
While the invention has been described in connection with various embodiments, other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a review of the drawings and the disclosure.
The foregoing is a more detailed description of the invention in connection with specific preferred embodiments and it is not intended that the invention be limited to these specific details. For those skilled in the art to which the invention pertains, several simple deductions or substitutions can be made without departing from the spirit of the invention, and all shall be considered as belonging to the protection scope of the invention.
Claims (10)
1. A passive pressure sensor based on piezoelectric potential enhanced triboelectric effect, comprising:
an electrode layer;
a flexible polymer material layer; the flexible high polymer material layer is positioned on the electrode layer;
a ZnO wrinkled layer; the ZnO wrinkled layer is positioned on the flexible high polymer material layer;
a ZnO nanowire layer; the ZnO nanowire layer is positioned on the ZnO wrinkle layer;
a negative friction layer; the negative friction layer is positioned above the ZnO nanowire layer;
the thickness of ZnO deposited when the ZnO wrinkled layer is manufactured is 10 nm-1 mu m, the thermal expansion coefficients of the flexible high polymer material for manufacturing the flexible high polymer material layer and the ZnO are not matched, and the top crystal face of the ZnO in the ZnO nanowire layer is a (0001) crystal face.
2. The passive pressure sensor based on piezoelectric potential enhanced triboelectric effect according to claim 1, further comprising: a spacer;
the spacer is positioned between the negative friction layer and the ZnO nanowire layer, and the occupied area of the spacer is smaller than that of the ZnO nanowire layer.
3. The passive pressure sensor according to claim 1 based on piezoelectric potential enhanced triboelectric effect, wherein the flexible polymeric material comprises: polydimethylsiloxane PDMS.
4. The passive pressure sensor based on piezoelectric potential enhanced triboelectric effect according to claim 1, wherein the material of the negative friction layer comprises: fluorinated ethylene propylene copolymer FEP.
5. A passive pressure sensor based on a piezoelectric potential enhanced triboelectric effect according to claim 1, characterized in that the electrode layer comprises: a substrate and a conductive layer over the substrate;
the material of the conducting layer includes: indium Tin Oxide (ITO);
the material of the substrate comprises: polyethylene terephthalate PET.
6. A preparation method of a passive pressure sensor based on piezoelectric potential enhanced triboelectric effect is characterized by comprising the following steps:
coating a flexible high polymer material on the electrode layer in a spinning mode to form a flexible high polymer material layer; the thermal expansion coefficients of the flexible high polymer material layer and ZnO are not matched;
depositing a layer of ZnO with the thickness of 10 nm-1 mu m on the flexible polymer material layer, and then cooling to form a ZnO wrinkle layer on the flexible polymer material layer;
growing ZnO nanowires on the ZnO wrinkled layer to form a ZnO nanowire layer;
sticking a negative friction layer on the ZnO nanowire layer to obtain a passive pressure sensor based on piezoelectric potential enhanced triboelectric effect;
and the top crystal face of ZnO in the ZnO nanowire layer is a (0001) crystal face.
7. The method of claim 6, further comprising:
before the negative friction layer is pasted on the ZnO nanowire layer, a spacer is placed on the ZnO nanowire layer, and the occupied area of the spacer is smaller than that of the ZnO nanowire layer.
8. The method for preparing the passive pressure sensor based on the piezoelectric potential enhanced triboelectric effect according to claim 6, wherein the step of depositing a layer of ZnO with the thickness of 10 nm-1 μm on the flexible polymer material layer comprises the following steps:
and depositing a layer of ZnO with the thickness of 10 nm-1 mu m on the flexible polymer material layer by adopting a magnetron sputtering process.
9. The method for preparing the passive pressure sensor based on the piezoelectric potential enhanced triboelectric effect according to claim 6, wherein growing ZnO nanowires on the ZnO wrinkled layer comprises:
and growing the ZnO nanowire on the ZnO wrinkled layer by adopting a room-temperature hydrothermal method.
10. The method for preparing the passive pressure sensor based on the piezoelectric potential enhanced triboelectric effect according to claim 6, wherein the height of the ZnO nanowire in the ZnO nanowire layer is 10 nm-50 μm.
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