KR20220033396A - Piezoelectric device and method for manufacturing the same - Google Patents

Abstract

A piezoelectric element according to an embodiment of the present invention includes: a first structure that includes a first substrate, a first electrode positioned on the first substrate, and a first piezoelectric layer positioned on the first electrode and including a ceramic piezoelectric material; and a second structure facing the first structure, a second electrode positioned on one surface of the second substrate facing the first structure, and a second piezoelectric material positioned on the second electrode and including a semiconductor piezoelectric material.

Description

Piezoelectric element and manufacturing method thereof

The present invention relates to a piezoelectric element and a method for manufacturing the same, and more particularly, to a piezoelectric element having an improved structure and a method for manufacturing the same.

Recently, the depletion of existing energy resources, such as oil and coal, is expected, raising the issue of environmental pollution. Accordingly, interest in eco-friendly and renewable energy sources is increasing. In order to meet these demands, energy harvesting, which converts energy generated from natural energy sources into electrical energy and harvests it, has been proposed.

As an example of such energy harvesting, a piezoelectric element that converts kinetic energy such as a movement of a human body, a movement of a machine, a minute operation, etc. into electrical energy may be mentioned. Energy sources such as movement of the human body and operation of machines used in the piezoelectric element are easy to control and sufficient harvesting is possible even indoors. In addition, the piezoelectric element may collect and recycle wasted energy, such as vibration generated when a person walks or runs, or an object passes, or pressure generated when a machine moves.

After the discovery of the piezoelectric effect of zinc oxide, a piezoelectric device in which a piezoelectric material in the form of nano-rods was grown on a substrate was developed for the first time. Such a piezoelectric element had low durability to withstand mechanical kinetic energy, pressure, and the like. Accordingly, a flexible piezoelectric element with improved durability by embedding a piezoelectric material in the form of nanoparticles into a polymer thin film has been developed. As such, when the durability problem was solved, research to increase the power output efficiency was conducted for commercialization. The power output efficiency was improved by controlling and optimizing the ratio of embedding the piezoelectric material into the polymer thin film.

After that, a technology for improving power output efficiency with a mixed structure in which a piezoelectric material is doped with a material having high electrical conductivity has been developed. This is because, when a material having high electrical conductivity is added, electron movement is activated by high electrical conductivity inside the thin film when polarization occurs in the piezoelectric material, so that piezoelectric potential can be increased. The first attempt was a carbon nano tube (CNT), in addition to copper (Cu) particles, graphene, etc. were used.

In addition, techniques such as patterning by etching or surface treatment of the surface of a thin film made of a piezoelectric material, or patterning a substrate, an electrode, etc. have been proposed. Even when the same pressure is applied to such a piezoelectric element, stress may be concentrated to amplify local polarization.

However, although the piezoelectric element having various structures as described above has been proposed, there is a limit to sufficiently improving durability and power output efficiency of the piezoelectric element.

Patent Document 1: Korean Patent Publication No. 10-2012-0058710 (Title of the Invention: Flexible Nano Generator Manufacturing Method and Flexible Nano Generator Manufactured thereby) Patent Document 2: Korean Patent Publication No. 10-2016-0146104 (Title of the Invention: Energy Harvesting System) Patent Document 3: Domestic Patent Publication No. 10-2017-0106099 (Title of the invention: piezoelectric pulse system using flexible piezoelectric pulsation element)

An embodiment of the present invention is to provide a piezoelectric element capable of improving durability and power output efficiency and a method of manufacturing the same.

In particular, an embodiment of the present invention is to provide a piezoelectric element capable of improving durability and power output efficiency using a lead-free piezoelectric material and a method for manufacturing the same.

On the other hand, an embodiment of the present invention is to provide a piezoelectric device and a method of manufacturing the same that can be applied to various fields such as wireless charging system construction, bio-electronic devices, wearable electronic devices, micro-electro-mechanical systems, etc. by utilizing permanent power generation. .

A piezoelectric element according to an embodiment of the present invention includes a first substrate, a first electrode positioned on the first substrate, and a first piezoelectric layer positioned on the first electrode and including a ceramic piezoelectric material. 1 structure; and a second substrate facing the first structure, a second electrode located on one surface of the second substrate facing the first structure, and a second piezoelectric material located on the second electrode and including a semiconductor piezoelectric material and a second structure comprising a layer.

A piezoelectric element according to another embodiment of the present invention includes a first piezoelectric element including a first substrate, a first electrode positioned on the first substrate, and a cluster positioned on the first electrode and made of a first piezoelectric material. a first structure comprising a layer; and a second substrate facing the first structure, a second electrode located on one surface of the second substrate facing the first structure, and a second electrode located on the second electrode and made of a spherical or and a second structure including a second piezoelectric layer having a pressure concentrating member having a shape constituting a part thereof.

A method of manufacturing a piezoelectric element according to an embodiment of the present invention includes: forming a first electrode on a first substrate and forming a second electrode on a second substrate; placing a first piezoelectric layer comprising a ceramic piezoelectric material over the first electrode to form a first structure and placing a second piezoelectric layer comprising a semiconductor piezoelectric material over the second electrode to form a second structure; and overlapping the first structure and the second structure so that the first piezoelectric layer and the second piezoelectric layer face each other.

In the piezoelectric element according to the present embodiment, various characteristics may be improved by including the first piezoelectric layer and the second piezoelectric layer having different materials and shapes. In this case, the first piezoelectric layer may include a ceramic piezoelectric material having excellent piezoelectric efficiency, and the second piezoelectric layer may include a semiconductor piezoelectric material having piezoelectric properties and a low bandgap and excellent electrical conductivity. Such a piezoelectric element may have very good durability and power output efficiency. For example, since the first and second piezoelectric layers are made of a lead-free piezoelectric material, it is possible to improve durability and power output efficiency while being eco-friendly. In particular, the first piezoelectric layer is composed of a cluster having an irregular shape or arrangement, and the second piezoelectric layer is composed of a pressure concentrating member having a uniform shape and a regular arrangement, thereby greatly improving the pressure concentration characteristics when pressure is applied. can do.

Such a piezoelectric device may be applied to various fields such as a wireless charging system construction, a bioelectronic device, a wearable electronic device, and a microelectromechanical system by utilizing permanent power generation.

1 is an exploded perspective view schematically illustrating a piezoelectric element according to an embodiment of the present invention.
FIG. 2 is a schematic cross-sectional view taken along line II-II of FIG. 1 .
3 is a plan view schematically illustrating a first piezoelectric layer included in the piezoelectric element shown in FIG. 1 .
4 is a diagram schematically illustrating a process of forming a first piezoelectric layer included in a piezoelectric element according to an embodiment of the present invention.
5 is a diagram schematically illustrating a process of forming a second piezoelectric layer included in a piezoelectric element according to an embodiment of the present invention.
6 is a scanning electron microscope photograph of ceramic nanoparticles according to Preparation Example 1 of the present invention.
7 is a scanning electron microscope photograph and X-ray diffraction analysis photograph of semiconductor particles according to Preparation Example 1 of the present invention.
8 is a scanning electron microscope photograph of a first structure including a first piezoelectric layer according to Preparation Example 1 of the present invention.
9 is a scanning electron microscope photograph of a second piezoelectric layer according to Preparation Example 1 of the present invention.
10 is a graph showing the results of voltage-current measured while applying pressure to the piezoelectric element according to Preparation Example 1 of the present invention with a finger.
11 is a graph showing the results of voltage-current measured while mechanically applying pressure to the piezoelectric element according to Preparation Example 1 and Comparative Example 1 of the present invention.
12 is a photograph showing a state in which the piezoelectric element according to Preparation Example 1 is connected to 200 blue light emitting diodes (LEDs), (a) is a photograph of a state in which the piezoelectric element is not pressed by hand pressure, (b) is This is a picture of the piezoelectric element being pressed with the pressure of the hand.
FIG. 13 is a picture of charging the piezoelectric element according to Preparation Example 1 by connecting a capacitor, and driving an electronic watch using the capacitor.
14 is a photograph of a process of measuring voltage characteristics in a state in which the piezoelectric element according to Preparation Example 1 is bent by hand and in a state in which it is not bent by hand.
15 is a photograph when the piezoelectric element according to Preparation Example 1 is attached to the wrist.
16 is a photograph when the piezoelectric element according to Preparation Example 1 is attached to the neck.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, it goes without saying that the present invention is not limited to these embodiments and may be modified in various forms.

In the drawings, in order to clearly and briefly describe the present invention, the illustration of parts irrelevant to the description is omitted, and the same reference numerals are used for the same or extremely similar parts throughout the specification. In addition, in the drawings, the thickness, width, etc. are enlarged or reduced in order to make the description more clear, and the thickness, width, etc. of the present invention are not limited to the bars shown in the drawings.

And, when a certain part "includes" another part throughout the specification, other parts are not excluded unless otherwise stated, and other parts may be further included. In addition, when a part of a layer, film, region, plate, etc. is said to be "on" another part, this includes not only the case where the other part is "directly on" but also the case where another part is located in the middle. When a part, such as a layer, film, region, or plate, is "directly above" another part, it means that no other part is located in the middle.

Hereinafter, a piezoelectric element and a method of manufacturing the same according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. In the present specification, the expression “first” or “second” is used to distinguish from each other, and the present invention is not limited thereto.

1 is an exploded perspective view schematically illustrating a piezoelectric element according to an embodiment of the present invention, and FIG. 2 is a schematic cross-sectional view taken along line II-II of FIG. 1 . 3 is a plan view schematically illustrating a first piezoelectric layer included in the piezoelectric element shown in FIG. 1 .

1 to 3 , the piezoelectric element 100 according to the present embodiment includes a first piezoelectric element including a first substrate 12 , a first electrode 14 , and a first piezoelectric material (ceramic piezoelectric material). a first structure 10 comprising a layer 16 , a second piezoelectric layer 26 comprising a second substrate 22 , a second electrode 24 and a second piezoelectric material (semiconductor piezoelectric material); It may include a second structure 20 that does. More specifically, the first electrode 14 may be positioned on the first substrate 12 , and the first piezoelectric layer 16 may be positioned on the first electrode 14 . In addition, the second electrode 24 may be positioned on one surface of the second substrate 22 facing the first structure 10 , and the second piezoelectric layer 26 may be positioned on the second electrode 24 . . This will be described in more detail.

In this embodiment, the first substrate 12 or the second substrate 22 may be composed of a flexible substrate having a flexible characteristic. For example, the first substrate 12 or the second substrate 22 may be made of polyethylene terephthalate (PET), polyimide (PI), polyethylene naphthalate (PEN), or the like. Here, the first substrate 12 and the second substrate 22 may be made of the same material or different materials. In this case, the thickness of the first substrate 12 or the second substrate 22 may be 50 μm to 125 μm. In this thickness range, the first substrate 12 or the second substrate 22 may have sufficient durability and flexibility. Here, the first substrate 12 and the second substrate 22 may have the same thickness or different thicknesses. However, the present invention is not limited thereto, and the material and thickness of the first substrate 12 or the second substrate 22 may be variously modified.

The first electrode 14 formed on the first substrate 12 or the second electrode 24 formed on the second substrate 22 may be made of a material having electrical conductivity, for example, a metal or a transparent conductive oxide. can For example, the first electrode 14 or the second electrode 24 may be formed of aluminum (Al), copper (Cu), indium-tin oxide (ITO), or the like. Here, the first electrode 14 and the second electrode 24 may be made of the same material or different materials. The first electrode 14 or the second electrode 24 may be manufactured by various methods, for example, by vapor deposition. For example, the first electrode 14 or the second electrode 24 may be formed by thermal evaporation. In this case, the first electrode 14 or the second electrode 24 may have a thickness of 100 nm to 300 nm. This is because, at such a thickness, the first electrode 14 or the second electrode 24 may have excellent electrical conductivity while maintaining flexible properties. Here, the first electrode 14 and the second electrode 24 may have the same thickness or different thicknesses. However, the present invention is not limited thereto, and the material and thickness of the first electrode 14 or the second electrode 24 may be variously modified.

For example, on the first electrode 14 or the second electrode 24 , between the first electrode 14 and the first piezoelectric layer 16 or between the second electrode 24 and the second piezoelectric layer 16 . A first buffer layer 18 or a second buffer layer 28 may be positioned. This first or second buffer layer 18 , 28 may serve as a buffer and packaging between the first or second electrode 14 , 24 and the first or second piezoelectric layer 16 , 26 , and is an insulating material can function as an insulating layer. As the first or second buffer layers 18 and 28 , polydimethylsiloxane (PDMS), polyvinylalcohol (PVA), polyvinylidene fluoride (PVDF), or the like may be used. For example, a thickness (eg, an average thickness) of the first or second buffer layers 18 and 28 may be 30 μm to 80 μm. Within this range, the buffering, packaging, and insulating properties of the first or second buffer layers 18 and 28 may be improved. However, the present invention is not limited thereto, and various modifications are possible for the material and thickness of the first or second buffer layers 18 and 28 .

A first piezoelectric layer 16 including a ceramic piezoelectric material and having flexible characteristics may be formed on the first electrode 14 (more specifically, on the first buffer layer 18 ). Here, the first piezoelectric layer 16 may include a resin and ceramic nanoparticles 16b made of a ceramic piezoelectric material. More specifically, the resin constitutes the resin layer 16a having a substantially uniform thickness, and a plurality of ceramic nanoparticles 16b are agglomerated to protrude or expose over the surface of the resin layer 16a (cluster) ( 16c) may be provided. In the present specification, having a substantially uniform thickness may mean having a difference between a large thickness and a small thickness of the corresponding layer within 20% (eg, within 10%) based on the large thickness. The clusters 16c may have an irregular shape, an irregular shape, or an irregular shape, have an irregular size, and may be distributed to have an irregular arrangement in a plan view. This is because the cluster 16c is generated by irregularly aggregating a plurality of ceramic nanoparticles 16b. At this time, having an irregular shape, an irregular shape, or an irregular shape means that the shape of the plurality of clusters 16c does not have a specific regularity and does not have a shape defined as a polygon, a circle, an oval, or a sphere. there is. And, having an irregular size may mean that the plurality of clusters 16c have different sizes. And, irregularly arranged may mean that the clusters 16c do not have a constant directionality, a regular interval, and a regular arrangement so that the cluster 16c does not have regularity. The cluster 16c may be formed by a certain manufacturing method, which will be described in detail later in the manufacturing method.

In this embodiment, the cluster 16c has a shape that protrudes from the surface of the resin layer 16a toward the second structure 20 as shown in FIG. 2(a), or in FIG. 2(b) As shown in , the resin layer 16a may have a shape protruding toward the second structure 20 in a state in which it is partially charged. As another example, the cluster 16c may have a shape in which it penetrates the entire resin layer 16a and protrudes toward the second structure 20 while in contact with the surface of the first electrode 14 . Although the cluster 16c is mainly illustrated in (a) and (b) of FIG. 2 , the ceramic nanoparticles 16b may be located inside or on the surface of the resin layer 16a, and the ceramic nanoparticles 16b may be It may be positioned in contact with the first electrode 14 or spaced apart from the first electrode 14 .

As such, since the cluster 16c has a shape in which a plurality of ceramic nanoparticles 16b are irregularly aggregated and protrude above the resin layer 16a, when the cluster 16c comes into contact with the second piezoelectric layer 26 by pressure, the pressure is locally applied. Concentrated pressure can be effectively increased. Accordingly, the piezoelectric properties can be effectively improved even if the thickness of the first piezoelectric layer 16 is not increased too much.

For example, the ceramic nanoparticles 16b may have a size of a nanometer level (ie, 1 nm or more, less than 1 μm), and the cluster 16c may have a size of a micrometer level (ie, 1 μm or more, less than 1 mm) or It may be a micro cluster having a thickness. Here, the size of the ceramic nanoparticles 16b may mean the average particle diameter of the plurality of ceramic nanoparticles 16b, and the size of the cluster 16c is the average of the long axes of the plurality of clusters 16c in a plan view. , and the thickness of the cluster 16c may mean an average of the maximum thickness of the cluster 16c when viewed from the side.

For example, the ceramic nanoparticles 16b may have a size of 100 nm to 500 nm, and may have a tetragonal crystal structure. It can be easily manufactured within this size range, and can be easily aggregated to form the cluster 16c to have a sufficient surface area. And as an example, the cluster 16c may have a size of 10um to 25um and a thickness of 10um or less (eg, 1um to 10um, for example, 3um to 8um). This is because, within this range, the effect of concentrating the pressure on the cluster 16c without damaging the second structure 20 can be maximized. However, the present invention is not limited thereto, and various modifications are possible.

For example, the thickness of the resin layer 16a may be, for example, 30 μm to 80 μm. Here, the thickness of the resin layer 16a may be defined as an average thickness. Although the first piezoelectric layer 16 may be stably formed within the thickness range of the resin layer 16a described above, the present invention is not limited thereto, and various modifications are possible.

In this embodiment, the ceramic nanoparticles 16b or the ceramic piezoelectric material may be formed of a material having excellent piezoelectric properties. For example, the ceramic nanoparticles 16b or the ceramic piezoelectric material may be barium titanate (BaTiO ₃ ), lead zirconate titanate (PZT), lead titanate (PbTiO ₃ ), lead zirconate (PbTiO ₃ ), or the like. In this embodiment, the ceramic nanoparticles 16b or ceramic piezoelectric material are used as the first piezoelectric material, but as the first piezoelectric material, nanoparticles or piezoelectric materials other than the ceramic nanoparticles 16b or the ceramic piezoelectric material are used. may be As an example, zinc oxide (ZnO) or the like may be used.

Here, when the ceramic nanoparticles 16b or the ceramic piezoelectric material is made of barium titanate, it is a lead-free material that does not contain lead, which is advantageous in terms of environment and may have excellent piezoelectric properties.

In addition, the resin layer 16a may be formed of various resins that stably fix or adhere the ceramic nanoparticles 16b while maintaining the flexible characteristics. For example, the resin layer 16a may include polydimethylsiloxane, polyvinyl alcohol, polyvinylidene fluoride, or the like. Here, when the resin layer 16a contains polydimethylsiloxane, the curing time is short, the manufacturing process time can be shortened, the surface durability can be improved, and it can have excellent flexible characteristics. However, the present invention is not limited thereto, and various modifications are possible.

In the present embodiment, the resin layer 16a in the first piezoelectric layer 16 may be included in an amount equal to or greater than that of the ceramic nanoparticles 16b. For example, in the first piezoelectric layer 16 , the resin layer 16a may be included in a content greater than that of the ceramic nanoparticles 16b. Since the ceramic nanoparticles 16b are provided in the form of clusters 16c, the content of the ceramic nanoparticles 16b does not need to be large. This is because the fixing or adhesive properties of 16c) can be improved.

For example, based on 100 parts by weight of the total first piezoelectric layer 16, the ceramic nanoparticles 16b may be included in 5 to 25 parts by weight, and the remainder may be composed of a resin or the resin layer 16a. Within this range, while sufficiently realizing the piezoelectric properties of the ceramic nanoparticles 16b, it is possible to improve the fixing or adhesion properties by the resin layer 16a. However, the present invention is not limited thereto.

A second piezoelectric layer 26 is formed on the second electrode 24 (more specifically, on the second buffer layer 28 ) to face the first piezoelectric layer 16 and includes a semiconductor piezoelectric material. can be The second piezoelectric layer 26 is formed of a base layer 26a having a uniform thickness as a whole, and a semiconductor piezoelectric material, and is arranged in rows and columns on the base layer 26a or on the base layer 26b. It may include a pressure concentrating member (26c) composed of a plurality of semiconductor particles (26b) arranged as. For example, the plurality of semiconductor particles 26b are provided singly in the thickness direction and have one row that is repeated at regular intervals along one direction as a whole on a plane, and a plurality of semiconductor particles 26b in a direction crossing the one direction. Columns may be provided and may be arranged to have a matrix shape.

In the present embodiment, the semiconductor particles 26b may have a shape that protrudes toward the first structure 10 in a state in which a portion is charged in the base layer 26a. That is, a portion of the semiconductor particle 26b may be located inside the surface of the base layer 26a and another portion of the semiconductor particle 26b may have a shape protruding from the surface of the base layer 26a.

As described above, the second piezoelectric layer 26 may include a semiconductor piezoelectric material to improve piezoelectric efficiency while effectively concentrating and providing pressure to the first piezoelectric layer 26 . The semiconductor particles 26b constituting the pressure concentrating member 26c may each have a spherical shape or a shape constituting a part of the spherical shape, and may be disposed to convexly protrude toward the first piezoelectric layer 16 . As described above, the semiconductor particles 26b having a spherical shape or a shape constituting a part of the spherical shape may be arranged on the base layer 26a to induce a stress concentration phenomenon to have an advantageous structure for activating piezoelectric properties.

In this embodiment, the semiconductor particles 26b may have a size of 100 nm to 5 μm (eg, 500 nm to 1 μm). For example, the semiconductor particles 26b may have a larger size than the ceramic nanoparticles 16b and have a smaller size than the cluster 16c. Here, the size of the semiconductor particles 26b may mean the average of particle diameters or long axes of the plurality of semiconductor particles 26b.

In this embodiment, the thickness of the second piezoelectric layer 26 is equal to or greater than that of the first piezoelectric layer 16, or the thickness of the base layer 26a is equal to or greater than the thickness of the resin layer 16a. can be large For example, the thickness of the second piezoelectric layer 26 may be greater than the thickness of the first piezoelectric layer 16 or the thickness of the base layer 26a may be greater than the thickness of the resin layer 16a, which is This is because the base layer 26a preferably has a relatively large thickness in order to stably fix the semiconductor particles 26c. For example, the thickness of the second piezoelectric layer 26 or the base layer 26a may be, for example, 50 μm to 150 μm. Here, the thickness of the second piezoelectric layer 26 or the base layer 26a may be defined as an average thickness.

In this embodiment, the semiconductor particles 26b or the semiconductor piezoelectric material may be zinc stenate (ZnSnO ₃ ) having excellent piezoelectric properties, and the like. The semiconductor particles 26b or the semiconductor piezoelectric material may have excellent electrical conductivity while having intrinsic piezoelectric properties to effectively improve piezoelectric efficiency. For example, the semiconductor particles 26b may have higher electrical conductivity than the ceramic nanoparticles 16b. And zinc stenate may have a stable spherical shape, so it is suitable to act as the pressure concentrating member 26c. As such, it may be difficult to expect the properties of zinc stenate having a spherical shape and piezoelectric properties from other materials.

In this embodiment, the semiconductor particles 26b may have an amorphous structure. When the semiconductor particle 26b has an amorphous structure, for example, if the semiconductor particle 26b is made of zinc stenate and has an amorphous structure, it can be easily and variously synthesized and piezoelectric even when the same pressure is applied to the piezoelectric element 100 . characteristics are better.

In addition, the base layer 26a may be formed of various resins that stably fix or adhere the semiconductor particles 26b while maintaining the flexible characteristics. For example, the base layer 26a may include polyvinyl alcohol or the like. When the base layer 26a contains polyvinyl alcohol, it has a solution form having adhesive properties before curing or drying, so that it is easy to apply as a whole. 262) while being easily separated, the semiconductor particles 26b can be stably fixed. The aggregation and fixing properties of polyvinyl alcohol may be difficult to expect from other materials. However, the present invention is not limited thereto, and various modifications are possible.

In the present embodiment, in the second piezoelectric layer 26, the base layer 26a may be included in an amount equal to or greater than that of the semiconductor particles 26b. For example, in the second piezoelectric layer 26 , the base layer 26a may be included in an amount greater than that of the semiconductor particles 26b. This is because it is preferable that the semiconductor particles 26b be provided as a single layer and the base layer 26a is preferably included in a large amount so as to improve the fixing or adhesion properties of the semiconductor particles 26b.

For example, based on 100 parts by weight of the total second piezoelectric layer 26 , 3 to 15 parts by weight of the semiconductor particles 26b may be included and the remainder may be composed of the base layer 26a. Within this range, while sufficiently realizing the piezoelectric properties of the semiconductor particles 26b, the fixing or adhesion properties of the base layer 26a can be improved. However, the present invention is not limited thereto.

A portion exposed without forming the first buffer layer 18, the first piezoelectric layer 16, etc. may be provided on a portion of one end (the left side of FIG. 2) on the first electrode 14, A first pad 19 for connection to an external circuit or the like may be provided in the exposed portion. And on the first electrode 14, the second buffer layer 28, the second piezoelectric layer 26, etc. are not formed on the portion of the other end (the right side of Fig. 2), the exposed portion may be provided. and a second pad 29 for connection to an external circuit or the like may be provided in the exposed portion. The first or second pads 19 and 29 may be made of a metal material having excellent electrical conductivity, or the like, and may have various shapes. For example, a metal paste (eg, silver paste) may be used as the first or second pads 19 and 29 . However, the present invention is not limited thereto.

The piezoelectric element 100 is manufactured by overlapping the first structure 10 and the second structure 20 so that the above-described first piezoelectric layer 16 and the second piezoelectric layer 26 face each other. In this case, the first piezoelectric layer 16 and the second piezoelectric layer 26 may overlap to provide a space (spacer) according to the surface shape. The first structure 10 and the second structure 20 may constitute the piezoelectric element 100 by being superimposed to have a space (spacer) without separate adhesion or fixation. The resin included in the first buffer layer 18 , the second buffer layer 28 , the first piezoelectric layer 16 and/or the second piezoelectric layer 26 has adhesive properties, so that the first and second structures 10 and 20 ) can be stably fixed to the piezoelectric element 100 including the. However, the present invention is not limited thereto, and the piezoelectric element 100 may be configured by bonding or fixing at least a portion of the first structure 10 and the second structure 20 using an adhesive or a fixing member. Various other modifications are possible.

The piezoelectric element 100 according to the present embodiment includes a first piezoelectric layer 16 and a second piezoelectric layer 26 having a sandwich structure facing each other. In this case, the first piezoelectric layer 16 may include a ceramic piezoelectric material having excellent piezoelectric efficiency, and the second piezoelectric layer 26 may include a semiconductor piezoelectric material having piezoelectric properties and a low bandgap and excellent electrical conductivity. there is. Such a piezoelectric element 100 may have very excellent durability and power output efficiency. For example, the first and second piezoelectric layers 16 and 26 may include a lead-free piezoelectric material to improve eco-friendly properties. In particular, in this embodiment, the first piezoelectric layer 16 is composed of clusters 16c having an irregular shape or arrangement, and the second piezoelectric layer 26 is a pressure concentrating member 26c having a uniform shape and regular arrangement. ) to greatly improve the pressure concentration characteristics when pressure is applied.

The power output efficiency of the piezoelectric element 100 according to the present embodiment is the sum of the power output efficiency of the piezoelectric element including the first piezoelectric layer 16 and the piezoelectric element having the second piezoelectric layer 26 alone. It has a value that is very, very much greater than the value. Therefore, it can be seen that the power output efficiency is not improved by simply including a plurality of piezoelectric layers in the piezoelectric element 100 according to the present embodiment.

In this case, as the ceramic piezoelectric material and the semiconductor piezoelectric material, materials that may have the same or similar structures and may be formed by the same or similar synthesis method may be used. For example, if barium titanate is used as the ceramic piezoelectric material and zinc stenate is used as the semiconductor piezoelectric material, it has the same perovskite structure and can be formed by the same hydrothermal method, resulting in a stable structure. can be formed and the manufacturing process can be simplified. For reference, zinc stenate can be easily synthesized in nano or micro particle form by hydrothermal synthesis, whereas zinc oxide or the like is difficult to synthesize in nano or micro particle form.

The piezoelectric element 100 can be applied to various fields such as a wireless charging system such as an auxiliary battery, a bio-electronic device, a wearable electronic device, and a micro-electro mechanical system (MEMS) by utilizing permanent power generation. there is.

That is, according to the piezoelectric element 100 according to the present embodiment, by applying pressure to the piezoelectric element 100 using the body, charging the battery, driving a desired operation of the electronic device, charging the battery, etc. It can be applied to various devices. For example, various operations, such as turning on a light or charging a battery, may be performed by using pressure by a finger, a pressure by a palm, a wrist movement, a neck movement, or the like. As an example, when pressure is applied to the piezoelectric element 100 according to the present embodiment according to the vocal cord ringing, the vocal cord ringing can be recognized, and it operates as a voice recognition device and/or user recognition device according to this by interlocking it with a door opening device, etc. can be used Alternatively, the piezoelectric element 100 according to the present embodiment may be included in the portable defibrillator to operate the defibrillator using body pressure when an emergency occurs. The piezoelectric element 100 according to the present embodiment may be used in various other fields.

Hereinafter, a method of manufacturing the piezoelectric element 100 according to an embodiment of the present invention will be described in detail with reference to FIGS. 4 and 5 along with FIGS. 1 to 3 . A detailed description of the same or extremely similar parts to the above description will be omitted and only different parts will be described in detail.

4 is a diagram schematically illustrating a process of forming the first piezoelectric layer 16 included in the piezoelectric element 100 according to an embodiment of the present invention, and FIG. 5 is a piezoelectric element ( It is a view schematically illustrating a process of forming the second piezoelectric layer 26 included in 100 .

First, the first electrode 14 may be formed on the first substrate 12 , and the second electrode 24 may be formed on the second substrate 22 . The first electrode 14 or the second electrode 24 may be formed by a vapor deposition method, for example, a thermal vapor deposition method.

Then, as shown in FIG. 4 , the first piezoelectric layer 16 may be formed, and as shown in FIG. 5 , the second piezoelectric layer 26 may be formed. More specifically, the first piezoelectric layer 16 and the second piezoelectric layer 26 may be formed by preparing the ceramic nanoparticles 16b and the semiconductor particles 26b, respectively, and using them. Hereinafter, the process of forming the ceramic nanoparticles 16b and the semiconductor particle 26b will be described first, and the process of forming the first piezoelectric layer 16 and the second piezoelectric layer 26 using these will be described, respectively.

The ceramic nanoparticles 16b may include barium titanate, lead zirconate titanate, lead titanate, or lead zirconate, and the semiconductor particles 26b may include zinc stenate. However, the present invention is not limited thereto. Accordingly, various materials may be used as the first piezoelectric material included in the first piezoelectric layer 16 , and various materials may be used as the second piezoelectric material included in the second piezoelectric layer 26 .

In the present embodiment, the ceramic nanoparticles 16b and the semiconductor particles 26b may be formed by various methods. For example, they may be formed by a hydrothermal synthesis method. In the hydrothermal synthesis method, the heat treatment temperature and time may be variously modified. In this case, the heat treatment temperature and time of the ceramic nanoparticles 16b may be smaller than the heat treatment temperature and time of the semiconductor particles 26 , respectively. For example, in the hydrothermal synthesis method for forming the ceramic nanoparticles 16b, heat treatment may be performed at 50 to 120 degrees for 10 minutes to 1 hour, and in the hydrothermal synthesis method for forming the semiconductor particles 26b, 100 to 150 The heat treatment can be performed for 1 hour to 5 hours in the figure. However, the present invention is not limited thereto, and various modifications are possible.

In this case, the semiconductor particles 26b may be added with ethanol serving as a reaction catalyst enzyme in order to form a spherical shape. The semiconductor particles 26b manufactured as described above may have an amorphous structure.

And, as shown in FIG. 4 , the first piezoelectric layer 16 may be formed using the ceramic nanoparticles 16b.

More specifically, as shown in FIGS. 4A and 4B , a mixed solution 162 is prepared by mixing the ceramic nanoparticles 16b with the resin solution 160a made of resin. The resin solution 160a may include polydimethylsiloxane, polyvinyl alcohol, polyvinylidene fluoride, or the like. For example, in the case of using polydimethylsiloxane as the resin solution 160a, the resin solution 160a itself is transparent, but the mixed solution 162 in which the ceramic nanoparticles 16b are sufficiently mixed with the resin solution 160a is opaque. It can have one color. Accordingly, it can be easily checked whether the mixed solution 162 is formed by sufficiently mixing the ceramic nanoparticles 16b with the resin solution 160a with the naked eye.

Here, in the mixed solution 162 , the weight part of the resin solution 160a may be greater than the weight part of the ceramic nanoparticles 16b . For example, with respect to 100 parts by weight of the total mixed solution 162 , 5 to 25 parts by weight of the ceramic nanoparticles 16b may be included and the remainder may be composed of the resin solution 160a. However, the present invention is not limited thereto, and the weight parts of the resin and the ceramic nanoparticles may be variously modified.

As shown in FIGS. 4C and 4D , the first piezoelectric layer 16 may be formed by locating the clusters 16c on the resin layer 16a or on the resin layer 16a. This process may be performed in a vacuum bar coater equipment, for example, may be performed by a blading method using a vacuum bar coater (blading method for vacuum-barcoater).

The mixed solution 162 is applied entirely on the first manufacturing substrate 164 and waiting until it is sufficiently diffused on the surface of the first manufacturing substrate 164 to form a layered shape. For example, it may wait for 5 to 30 minutes after applying the mixed solution 162 . This is limited so that the process time is not too long while implementing sufficient diffusion, but the present invention is not limited thereto. In addition, a blading process may be performed on the layered mixed solution 162 using a bar coater. For example, when the bar 166 is etched while passing over the surface of the mixed solution 162 at a bar-shifting speed of 3 cm/s to 10 cm/s, the ceramic nanoparticles 16b and the resin solution Aggregation of the ceramic nanoparticles 16b may occur due to a difference in surface tension of the resin included in 160b. The moving speed (surface etching rate) of the bar 166 is appropriately limited to form the cluster 16c, but the present invention is not limited thereto. When the ceramic nanoparticles 16b are aggregated in this way, the aggregated ceramic nanoparticles 16b are again deposited as patterning on the surface of the layered mixed solution 162 (more precisely, the resin layer 16a made of resin). Thus, a cluster 16c can be formed. When cured in this state, the first piezoelectric layer 16 in which the clusters 16c are exposed or protrude on the surface of the resin layer 16a can be manufactured. For example, the curing process may be performed by a soft bake, and may be performed at a temperature of 60°C to 80°C for 1 hour to 5 hours. These process conditions are limited to simplify the manufacturing process while the curing process is stably performed, but the present invention is not limited thereto.

And as shown in FIG. 4E, the first piezoelectric layer 16 is separated from the first manufacturing substrate 164 and fixed on the first electrode 14 to manufacture the first structure 10 can complete For example, the first structure 10 may be formed by sequentially positioning and fixing the first buffer layer 18 and the first piezoelectric layer 16 on the first electrode 14 . At this time, the first buffer layer 18 may serve as a kind of adhesive layer.

And, as shown in FIG. 5 , the second piezoelectric layer 26 may be formed using the semiconductor particles 26b. This process may be performed by a substrate transfer method.

More specifically, as shown in FIGS. 5A and 5B , the semiconductor particles 26b are placed on the second manufacturing substrate 262 made of resin and rubbed using the transfer member 264 to obtain the second It is uniformly transferred onto the manufacturing substrate 262 . Accordingly, the semiconductor particles 26b may be aligned in a uni-directional manner to form columns and rows in a direction crossing each other. Here, the second manufacturing substrate 262 or the transfer member 264 may be made of polydimethylsiloxane, but the present invention is not limited thereto.

Subsequently, as shown in FIG. 5C , an aqueous resin solution 260a including a resin may be coated on the semiconductor particles 26b aligned on the second manufacturing substrate 262 . The aqueous resin solution 260a including the resin serves to bond and fix the semiconductor particles 26b and may include various materials that can be easily peeled off from the second manufacturing substrate 262 after curing. For example, the aqueous resin solution 260a may include polyvinyl alcohol or the like.

In this embodiment, the aqueous resin solution 260a contains 3 to 15 parts by weight of the semiconductor particles 26b based on 100 parts by weight of the total second piezoelectric layer 26 after curing or drying, and the remainder is used as the base layer 26a. It may be included in an amount to be constituted.

Subsequently, as shown in FIG. 5D , the aqueous resin solution 260a applied to the semiconductor particles 26b aligned on the second manufacturing substrate 262 may be dried or cured. In this case, since an air layer may be formed when the aqueous resin solution 260a containing the resin is applied, the curing process or the drying process may be performed in a vacuum state. For example, it may be cured by drying in a vacuum oven at room temperature for 6 to 15 hours. These process conditions are limited to simplify the manufacturing process while the curing process or the drying process is stably performed, but the present invention is not limited thereto. Accordingly, the second piezoelectric layer 26 to which the semiconductor particles 26b are uniformly transferred to the surface may be manufactured.

Next, as shown in FIG. 5E , the second piezoelectric layer 26 is separated from the second manufacturing substrate 262 , and this is fixed on the second electrode 24 to form the second structure 20 . manufacturing can be completed. For example, the second structure 20 may be formed by sequentially positioning and fixing the second buffer layer 28 and the second piezoelectric layer 26 on the second electrode 24 . At this time, the second buffer layer 28 may serve as a kind of adhesive layer.

Subsequently, the piezoelectric element 100 may be manufactured by overlapping the first structure 10 and the second structure 20 so that the first piezoelectric layer 16 and the second piezoelectric layer 26 face each other.

Hereinafter, a piezoelectric element according to this embodiment will be described in detail by way of a manufacturing example of the present invention. This preparation example is merely presented as an example, and the present invention is not limited thereto.

Preparation Example 1

A first electrode with a thickness of 100 nm made of aluminum was formed by thermal evaporation on a first substrate made of polyethylene terephthalate. Similarly, a 100 nm thick second electrode made of aluminum was formed by thermal evaporation on a second substrate made of polyethylene terephthalate.

Ceramic nanoparticles and semiconductor particles were respectively formed by hydrothermal synthesis. More specifically, ceramic nanoparticles composed of barium titanate were formed by hydrothermal synthesis, annealed at 70°C for 30 minutes, and dried. Then, using a hydrothermal synthesis method, semiconductor particles composed of zinc stenate were formed and annealed at 120°C for 90 minutes. In the hydrothermal synthesis method for forming zinc stenate, ethanol serving as a catalytic enzyme was added to make the crystal structure into a spherical shape. A scanning electron microscope (SEM) photograph of the ceramic nanoparticles thus formed is attached to FIG. 6 , and a scanning electron microscope photograph and an X-ray diffraction analysis (XRD) photograph of the semiconductor particles are attached to FIG. 7 .

A mixed solution was prepared by mixing ceramic nanoparticles in a resin solution containing polydimethylsiloxane in a weight ratio of 100:20. After pouring the mixed solution on the first manufacturing substrate of the vacuum bar coater equipment, wait for about 10 minutes until it diffuses, and then etch using a bar at a rate of 6 cm/s to form a cluster composed of ceramic nanoparticles, which is again a mixed solution It was deposited by scattering and patterning on the surface of This was cured in an oven at 700° C. for 2 hours to form a first piezoelectric layer. A scanning electron microscope photograph of the first structure in which the first piezoelectric layer is formed is attached to FIG. 8 . 8 is a photograph in which the surface of the first piezoelectric layer is analyzed in a tilt-view mode.

Then, after placing the semiconductor particles on the second manufacturing substrate made of polydimethylsiloxane, it was transferred evenly by rubbing using a transfer member made of polydimethylsiloxane. Then, an aqueous resin solution containing polyvinyl alcohol was applied on the semiconductor particles aligned on the second manufacturing substrate. The weight ratio of the aqueous resin solution to the semiconductor particles was 100:10. The second piezoelectric layer including semiconductor particles was formed on the base layer including polyvinyl alcohol by drying and curing the mixture at room temperature for 12 hours in a vacuum oven. As described above, a scanning electron microscope photograph of the second piezoelectric layer including the base layer and the semiconductor particles is attached to FIG. 9 . 9 is a photograph obtained by analyzing the surface of the second piezoelectric layer in a tilt-view mode.

The first and second piezoelectric layers were separated from the first and second production substrates, respectively. A first structure is formed by sequentially positioning and fixing a first buffer layer and a first piezoelectric layer made of polydimethylsiloxane on the first electrode, and a second buffer layer and a second piezoelectric layer made of polydimethylsiloxane on the second electrode A second structure was formed by sequentially positioning and fixing. A piezoelectric element was manufactured by fixing the first structure and the second structure in a state where the first piezoelectric layer and the second piezoelectric layer were opposed to each other.

Referring to FIG. 6 , the size of the ceramic nanoparticles was 100 nm to 500 nm and had a crystalline structure of a tetragonal electric field. Referring to FIG. 7 , it can be seen that the average size of the semiconductor particles is about 800 nm and has a spherical shape. And it can be seen that the semiconductor particles have an amorphous shape through the X-ray diffraction analysis result.

Referring to FIG. 8 , in the first piezoelectric layer, it can be seen that a cluster in which ceramic nanoparticles are aggregated is formed on the surface of the resin layer. In addition, it can be seen that the thickness of the first piezoelectric layer is also uniform at 50 μm. Referring to FIG. 9 , in the second piezoelectric layer, it can be seen that spherical semiconductor particles are uniformly patterned on the surface of the base layer.

In the state linked to the oscilloscope, the voltage-current characteristics were measured while simultaneously applying pressure to the piezoelectric element according to Preparation Example 1 of the present invention with two fingers of the index and middle fingers and pressing it with a pressure of 0.27 MPa, and the results are shown in FIG. (a) and (b) are attached. The result of the open-circuit voltage according to time is attached to FIG. 10(a), and the result of the short-circuit current according to time is attached to FIG. 10(b). In each of (a) and (b) of FIG. 10 , the result of the state connected in the forward direction is shown on the left side, and the result of the state connected in the reverse direction is shown on the right side.

As shown in (a) and (b) of Fig. 10, the peak output voltage was 206V, and the peak output current was 27uA. It can be seen that substantially the same output voltage and current can be obtained even when connected in the forward direction and when connected in the reverse direction, and only the directions are opposite. As described above, it can be seen that in the piezoelectric element according to the present embodiment, voltage and current output are sufficiently generated by the pressure of the finger.

And in the state linked to the oscilloscope, the voltage-current characteristics were measured by pressing the piezoelectric element according to Preparation Example 1 of the present invention with a machine of 0.13 MPa, and the results are attached to the right side of each of FIGS. 11 (a) and (b) did At this time, the machine providing pressure to the piezoelectric element moved a square rod having the size of the piezoelectric element and having an interval of 10 cm at a speed of 17 m/s to apply pressure with constant kinetic energy (constant mechanical kinetic energy). The result of the open-circuit voltage according to time is attached to FIG. 11(a), and the result of the short-circuit current according to time is attached to FIG. 11(b). The voltage-current characteristics of Comparative Example 1 having the first piezoelectric layer but not including the second piezoelectric layer are shown on the left side in each of FIGS. 11A and 11B .

Referring to FIGS. 11A and 11B , it can be seen that the average voltage and average current of the piezoelectric element according to Preparation Example 1 are very large compared to Comparative Example 1. Accordingly, it can be seen that the average power output efficiency is greatly increased to about 9.5 times.

Preparation 2

The piezoelectric element according to Preparation Example 1 was linked to a rectifier circuit and connected to 200 blue light emitting diodes (LEDs) connected in parallel. Pictures of the state in which the piezoelectric element is not pressed and the state in which the piezoelectric element is pressed by hand pressure (0.27 MPa) are attached to FIGS. 12 (a) and (b), respectively.

As shown in (a) of FIG. 12, the blue light emitting diode does not turn on when no pressure is applied to the piezoelectric element, but when pressure is applied to the piezoelectric element as shown in FIG. 12 (b), 200 blue light emitting diodes are You can see that all are turned on. As described above, it can be seen that sufficient power is generated using the piezoelectric element according to Preparation Example 1. Accordingly, the piezoelectric element according to the present embodiment can be applied to a wireless charging device, a wearable electronic device, a biomedical device, and the like.

Preparation 3

Three piezoelectric elements according to Preparation Example 1 were connected in parallel, and five 250uF capacitors were connected in parallel at the end of the rectifier circuit, and the capacitor was charged by pressing the piezoelectric element with the pressure of the palm of the hand (0.27 MPa). Then, by separating the capacitor from the piezoelectric element, the electronic watch was driven in conjunction with the electronic watch having a rated voltage of 3V. A photograph of this process is attached to FIG. 13 .

As shown in FIG. 13 , the power of the electronic watch could be turned on using a capacitor charged using a piezoelectric element. More specifically, the electronic clock could be driven for about 5 minutes using the capacitor charged by pressing the piezoelectric element for 2 minutes. As described above, it can be seen that sufficient power is generated using the piezoelectric element according to Preparation Example 1. Accordingly, the piezoelectric element according to the present embodiment can be applied to a wireless charging device, a wearable electronic device, a biomedical device, and the like.

Preparation 4

Voltage characteristics of the piezoelectric element according to Preparation Example 1 in a bent state and an unbent state were measured. A photograph of this process is attached to FIG. 14 .

Referring to FIG. 14 , voltage characteristics in a bent state of the piezoelectric element according to Preparation Example 1 are similar to those in an unbent state. As described above, when the piezoelectric element according to the present embodiment is used, desired piezoelectric characteristics can be realized even in a bent state, so that the piezoelectric element according to the present embodiment can be applied to a wearable electronic element, a biomedical device, and the like.

Preparation 5

The piezoelectric element according to Preparation Example 1 was attached to a body part (ie, wrist and neck), respectively, and the voltage was measured in conjunction with an oscilloscope. Here, the piezoelectric element according to Preparation Example 1 was attached to a body part using an insulating tape (polyimide tape, Kapton tape), and the voltage was measured for 1 minute in 3 cycles based on the oscilloscope. A photograph when the piezoelectric element according to Preparation Example 1 was attached to the wrist is shown in FIG. 15 , and a photograph when the piezoelectric element according to Preparation Example 1 is attached to the neck is shown in FIG. 16 .

As shown in FIG. 15, when the piezoelectric element is attached to the wrist, a voltage similar to that when the piezoelectric element is directly bent with a finger is measured, and when the piezoelectric element is attached to the neck as shown in FIG. The voltage was measured according to the vocal cord ringing. As described above, the piezoelectric element according to the present embodiment has high sensitivity and thus can be applied to a wearable electronic element, a biomedical device, and the like. For example, the vocal cord ringing may be recognized and used in conjunction with a door opening device or the like through voice recognition and user recognition.

The features, structures, effects, etc. as described above are included in at least one embodiment of the present invention, and are not necessarily limited to only one embodiment. Furthermore, the features, structures, effects, etc. illustrated in each embodiment can be combined or modified for other embodiments by those of ordinary skill in the art to which the embodiments belong. Accordingly, the contents related to such combinations and modifications should be interpreted as being included in the scope of the present invention.

100: piezoelectric element
10: first structure
12: first substrate
14: first electrode
16: first piezoelectric layer
18: first buffer layer
20: second structure
22: second substrate
24: second electrode
26: second piezoelectric layer
28: second buffer layer

Claims (21)

a first structure including a first substrate, a first electrode positioned on the first substrate, and a first piezoelectric layer positioned on the first electrode and including a ceramic piezoelectric material; and
A second substrate facing the first structure, a second electrode located on one surface of the second substrate facing the first structure, and a second piezoelectric layer located on the second electrode and including a semiconductor piezoelectric material A second structure comprising
A piezoelectric element comprising a. According to claim 1,
The piezoelectric element wherein the first piezoelectric layer includes a resin and ceramic nanoparticles composed of the ceramic piezoelectric material. 3. The method of claim 2,
In the first piezoelectric layer, the resin constitutes a resin layer, and a plurality of ceramic nanoparticles are agglomerated and are provided in the form of a cluster protruding or exposed above the surface of the resin layer. 4. The method of claim 3,
A piezoelectric element in which the clusters have an irregular shape and are irregularly arranged. 4. The method of claim 3,
The size of the ceramic nanoparticles is 100nm to 500nm,
The size of the cluster is 10um to 25um,
A piezoelectric element having a thickness of the resin layer of 30 μm to 80 μm. 3. The method of claim 2,
The resin comprises at least one of polydimethylsiloxane (PDMS), polyvinyl alcohol (PVA), and polyvinylidene fluoride (PVF),
The ceramic nanoparticles are barium titanate (BaTiO ₃ ), lead zirconate titanate (PZT), lead titanate (PbTiO ₃ ), and a piezoelectric element comprising at least one of lead zirconate (PbTiO ₃ ). According to claim 1,
The second piezoelectric layer includes a base layer and a piezoelectric element comprising a pressure concentrating member made of the semiconductor piezoelectric material and comprising a plurality of semiconductor particles regularly arranged in rows and columns at or on the base layer. device. 8. The method of claim 7,
A piezoelectric element in which the semiconductor particles are spherical or form a part of a sphere and convexly protrude toward the first piezoelectric layer. 8. The method of claim 7,
The semiconductor particles have a size of 100nm to 5um,
A piezoelectric element having a thickness of 50 μm to 150 μm of the second piezoelectric layer or the base layer. 8. The method of claim 7,
The base layer contains polyvinyl alcohol,
A piezoelectric element in which the semiconductor particles include zinc stenate. 8. The method of claim 7,
The first piezoelectric layer includes a resin layer composed of a resin, and ceramic nanoparticles composed of the ceramic piezoelectric material and forming a cluster shape that is agglomerated and protruded or exposed above the surface of the resin layer,
The thickness of the second piezoelectric layer is equal to or greater than the thickness of the first piezoelectric layer, or the thickness of the base layer is equal to or greater than the thickness of the resin layer,
A piezoelectric element in which the semiconductor particles have a larger size than the ceramic nanoparticles and have a smaller size than the cluster. a first structure including a first substrate, a first electrode positioned on the first substrate, and a first piezoelectric layer positioned on the first electrode and having a cluster formed of a first piezoelectric material; and
A second substrate facing the first structure, a second electrode located on one surface of the second substrate facing the first structure, and a second electrode located on the second electrode and composed of a second piezoelectric material, spherical or its A second structure including a second piezoelectric layer including a pressure concentration member of a shape constituting a part
A piezoelectric element comprising a. 13. The method according to any one of claims 1 to 12,
The piezoelectric element is a piezoelectric element used as a wireless charging system, a bioelectronic element, a wearable electronic element, a microelectromechanical system, a defibrillator, a voice recognition device, or a user recognition device. forming a first electrode on the first substrate and forming a second electrode on the second substrate;
forming a first structure by placing a first piezoelectric layer including a ceramic piezoelectric material on the first electrode and forming a second structure by placing a second piezoelectric layer including a semiconductor piezoelectric material on the second electrode; and
overlapping the first structure and the second structure so that the first piezoelectric layer and the second piezoelectric layer face each other
A method of manufacturing a piezoelectric element comprising a. 15. The method of claim 14,
The method of manufacturing a piezoelectric element wherein the first piezoelectric layer is formed by a blading method using a vacuum bar coater. 16. The method of claim 15,
The first piezoelectric layer,
forming a layered shape by applying a mixed solution in which a resin and ceramic nanoparticles composed of the ceramic piezoelectric material are mixed;
performing a blading process using a bar on the layered mixed solution so that the ceramic nanoparticles are agglomerated; and
Positioning the agglomerated ceramic nanoparticles on a resin layer made of the resin to form a cluster composed of the ceramic nanoparticles that protrudes or is exposed above the surface of the resin layer
A method of manufacturing a piezoelectric element formed including a. 17. The method of claim 16,
The resin comprises at least one of polydimethylsiloxane, polyvinyl alcohol, and polyvinylidene fluoride,
The method of manufacturing a piezoelectric element wherein the ceramic nanoparticles include at least one of barium titanate, lead zirconate titanate, lead titanate, and lead zirconate. 15. The method of claim 14,
The method of manufacturing a piezoelectric element wherein the second piezoelectric layer is formed by a substrate transfer method. 19. The method of claim 18,
The second piezoelectric layer,
placing semiconductor particles on a second manufacturing substrate and rubbing them using the transfer member to align and transfer the semiconductor particles on the second manufacturing substrate;
applying an aqueous resin solution including a resin on the semiconductor particles aligned on the second manufacturing substrate; and
Drying or curing the aqueous resin solution to prepare a base layer composed of the resin included in the aqueous resin solution and a second piezoelectric layer in which the semiconductor particles are aligned on a surface of the base layer
is formed, including
The method of manufacturing a piezoelectric element, wherein the second piezoelectric layer is separated from the second manufacturing substrate and fixed on the second electrode to form the second structure. 20. The method of claim 19,
The method of manufacturing a piezoelectric element in which the semiconductor particles constitute a spherical shape or a part of a sphere and convexly protrude toward the first piezoelectric layer. 20. The method of claim 19,
The base layer contains polyvinyl alcohol,
A method of manufacturing a piezoelectric element wherein the semiconductor particles include zinc stenate.

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