KR102467561B1 - Triboelectric nanogenerator and the manufacturing method thereof - Google Patents

Abstract

The present invention discloses triboelectric nanogenerators and methods of making triboelectric nanogenerators. A triboelectric nanogenerator according to an embodiment of the present invention includes a lower electrode formed on a first substrate; a negative friction layer formed on the lower electrode; a positive friction layer formed on the second substrate and used as an upper electrode; and at least one spacer formed between the first substrate and the second substrate and maintaining a distance between the first and second substrates, wherein the negative friction layer includes a polymer material and a nano material; , The nanomaterial is characterized in that recombination between electrons generated in the negative friction layer and positive ions absorbed by the surface of the negative friction layer due to friction between the negative friction layer and the positive friction layer is improved.

Description

Triboelectric nanogenerator and its manufacturing method

The present invention relates to a triboelectric nanogenerator and a method for manufacturing the same, and more particularly, to a highly efficient triboelectric nanogenerator capable of preventing spontaneous loss of electrons generated by friction and a method for manufacturing the same.

Triboelectric nanogenerator (TENG), which converts mechanical energy into electrical energy, has been actively researched and developed for its high energy conversion efficiency, low manufacturing cost, simple and bendable structure, and its ability to be manufactured with various materials. are losing The performance of TENG is greatly influenced by the amount of charge generated through friction and the efficiency of the process of separating positive and negative charges.

In general, two methods are applied to improve the performance of TENGs. First, there is a method of increasing the amount of electric charge generated in the friction process by using an appropriate friction material having a significantly different polarity, and the second method is to make the friction layer a surface with a micro or nano structure or to modify the surface on a nano scale. (surface modification).

In particular, in the second method, since it is important to effectively separate generated positive and negative charges, it has a great influence on determining the device structure. Therefore, the performance of the TENG has been improved through new structures such as a linear grating structure, a rolling structure, and a planar structure.

Furthermore, a method of increasing the surface charge density by injecting ionized air has been applied to improve the performance of TENG.

As such, although various improvements have been proposed to improve the performance of TENG, TENG is still a promising technology in the future, such as large-area integration, integration of mature and solid technologies, and development of cutting edge structures (cutting edge design). effort is required.

In addition, inside the TENG, a vertical electric field exists between the negative friction layer and the positive friction layer, and there are two mechanisms by which electrons move in the negative friction layer: the drifting process by the electric field and the diffusion by the concentration difference. It is a process.

Both methods result in the loss of electrons generated by friction because they recombine with positive ions from the electrodes. In addition, electrons on the surface part generated by friction adsorb positive charges or are annihilated by combining with particles in the air and the amount of absorbed positive charge.

Therefore, the amount of electrons generated by friction decreases, resulting in deterioration of the performance of the TENG.

Korean Patent Registration No. 10-1788733, "Friction Power Generation Element and Manufacturing Method Thereof" Korean Patent Registration No. 10-1714122, "Composite for triboelectric generator element, manufacturing method thereof, and triboelectric generator element comprising the same"

An object of the embodiments of the present invention is to include nanomaterials in the negative friction layer so that electrons generated in the negative friction layer and positive ions absorbed on the surface of the negative friction layer by friction between the negative friction layer and the positive friction layer are connected. It is to manufacture a triboelectric nanogenerator capable of preventing spontaneous loss of electrons generated by preventing recombination.

An object of the embodiments of the present invention is to trap electrons generated in the negative friction layer by friction between the negative friction layer and the positive friction layer by including nanomaterials in the negative friction layer, and the generated electrons are spontaneously lost. It is to prevent this and improve power efficiency to manufacture a high-efficiency triboelectric nanogenerator.

An object of the embodiments of the present invention is to include a single-layer crystal nanomaterial in the negative friction layer, so that the specific surface area of the region to which electrons generated in the negative friction layer are attached by friction between the negative friction layer and the positive friction layer (Specific Surface Area) is improved to manufacture a high-efficiency triboelectric nanogenerator in which the number of electrons trapped in the negative friction layer is maximized by friction between the negative friction layer and the positive friction layer.

A triboelectric nanogenerator according to an embodiment of the present invention includes a lower electrode formed on a first substrate; a negative friction layer formed on the lower electrode; a positive friction layer formed on the second substrate and used as an upper electrode; and at least one spacer formed between the first substrate and the second substrate and maintaining a distance between the first and second substrates, wherein the negative friction layer includes a polymer material and a nano material; , The nanomaterial improves recombination between electrons generated in the negative friction layer and positive ions absorbed by the surface of the negative friction layer due to friction between the negative friction layer and the positive friction layer.

The generated electrons may be trapped in the nanomaterial.

The number of trapped electrons can be controlled by the thickness of the negative friction layer and the concentration of the nanomaterial.

The negative friction layer may be dispersed on the surface of the polymer thin film including the polymer material.

The negative friction layer may include a first layer including the polymer material, a second layer including the polymer material and nanomaterial, and a third layer including the polymer material.

The nanomaterial may include at least one of nanoparticles, single-layer crystals, multilayer crystals, quantum dots, core-shell quantum dots, nanowires, nanoripples, nanotubes, nanorods, nanosheets, nanofibers, aerogels, and nanoforms. can

The nanoparticles are Au, Al, In, Ga, Ag, AuCl ₃ , reduced graphene oxide, graphene, single-wall CNT, double-wall carbon nanotube wall CNT) and at least one of Ni _x Fe ₁ - _x .

The single-layer crystal and the multi-layer crystal are molybdenum disulfide (MoS ₂ ), molybdenum diselenide (MoSe ₂ ), boron nitride (BN), graphene (grapheme), molybdenum telluride (MoTe), mica (Mica), and itelurium. It may include at least one of molybdenum (MoTe ₂ ) and black phosphorus (black phosphorus).

The quantum dots are Si, Ge, GaAs, InP, InAs, AlAs, InSb, AlGa _x As _{1 -x} , InGaxAs1-x, CdSe, CdTe, ZnSe, ZnTe, CdTe _x Se _{1 -x} , HgTe, HgCd _x Te _{1 - x} , ZnO, GaN, Al _x Ga _{1 - x} N, SnO ₂ , CuO, Cu2O, C ₆ 0, Cu ₂ ZnSnS ₄ , CuInS ₂ , SrTiO ₃ , BaTiO ₃ , (Ga _{1 - x} Mn _x )N, ( In _{1 - x} Mn _x ) N, CsPbCl ₃ , CdTe/ZnTe, may include at least one of.

The core-shell quantum dots are CdSe / CdTe, CdSe / CdS, InP / GaAs, CuInS / ZnTe, CuInS / CdS, CdSe / ZnS, Cd _{1 - x} ZnxTe / ZnTe, GaAs / Si, ZnSe / GaAs, CuInS / ZnS, At least one of Si/Si _x Ge _1-x , Au/SiO ₂ , InAs/GaAs, InP/GaAs/InAs, and CdSe/CdS/ZnS may be included.

The nanowire may include at least one of CeO ₂ , CdTe, ZnTe, SiO ₂ , Al ₂ O ₃ , ZnO, GaN, TiO ₂ , SnO ₂ , CuO, CuO ₂ , and CH ₃ NH ₃ PbI ₃ .

The nanorod may include at least one of CeO ₂ , CdTe, ZnTe, ZnO, GaN, TiO ₂ , SnO ₂ , CuxO, and CuO ₂ .

The nanoripple may include at least one of CeO ₂ , CdTe, ZnTe, ZnO, GaN, TiO ₂ , SnO ₂ , CuxO, and CuO ₂ .

The nanotube may include at least one of CeO ₂ , CdTe, ZnTe, ZnO, GaN, TiO ₂ , SnO ₂ , CuxO, and CuO ₂ .

The polymer material may include at least one of polytetrafluoroethylene, polydimethylsiloxane, polyvinyl chloride, polyimide, polypropylene, and polystyrene.

A method for manufacturing a triboelectric nanogenerator according to an embodiment of the present invention includes forming a lower electrode on a first substrate; forming a negative friction layer formed on the lower electrode; forming a positive friction layer used as an upper electrode on a second substrate; and forming at least one spacer formed between the first substrate and the second substrate and maintaining a distance between the first and second substrates, wherein the negative friction layer comprises a polymer material and nano The nanomaterial improves recombination between electrons generated in the negative friction layer and positive ions absorbed by the surface of the negative friction layer due to friction between the negative friction layer and the positive friction layer.

Forming the negative friction layer may include forming a first layer including the polymer material on the lower electrode; forming a second layer including the polymer material and the nano material on the first layer; A step of forming a third layer including the polymer material on the second layer may be included.

According to embodiments of the present invention, by including nanomaterials in the negative friction layer, friction between the negative friction layer and the positive friction layer causes electrons generated in the negative friction layer and positive ions absorbed on the surface of the negative friction layer to be separated. By preventing recombination, it is possible to manufacture a triboelectric nanogenerator capable of preventing spontaneous loss of generated electrons.

According to embodiments of the present invention, nanomaterials are included in the negative friction layer to trap electrons generated in the negative friction layer by friction between the negative friction layer and the positive friction layer, and the generated electrons are spontaneously lost. By preventing this, the power efficiency is improved, and a high-efficiency triboelectric nanogenerator can be manufactured.

According to embodiments of the present invention, the negative friction layer includes nanomaterials of single-layer crystals, and the specific surface area of the region to which electrons generated in the negative friction layer are attached by friction between the negative friction layer and the positive friction layer It is possible to manufacture a highly efficient triboelectric nanogenerator in which the number of electrons trapped in the negative friction layer is maximized by friction between the negative friction layer and the positive friction layer by improving the specific surface area.

Referring to FIG. 1 , it is a cross-sectional view showing a triboelectric nanogenerator according to embodiments of the present invention.
2a is a diagram showing a three-dimensional view of a triboelectric nanogenerator according to an embodiment of the present invention.
FIG. 2b shows a second layer of the negative friction layer of a triboelectric nanogenerator according to an embodiment of the present invention.
3 shows an optical image of a triboelectric nanogenerator according to an embodiment of the present invention.
4 shows a scanning electron microscope (SEM) measurement image of a cross section of a negative friction layer included in a triboelectric nanogenerator according to an embodiment of the present invention.
5A to 5D are graphs showing open-circuit voltages of triboelectric nanogenerators according to an embodiment of the present invention.
6A to 6F show graphs and energy bands illustrating electron trap mechanisms.
7A is a graph showing an open circuit voltage according to a thickness of a second layer (PI:rGO) included in a triboelectric nanogenerator according to an embodiment of the present invention.
FIG. 7B is a graph showing the open circuit voltage according to the rGO concentration of the second layer (PI:rGO) included in the triboelectric nanogenerator according to an embodiment of the present invention.
8 is a graph showing output voltage and current density according to external loading resistance of a triboelectric nanogenerator according to an embodiment of the present invention.
9 is a graph showing the output power density according to the external loading resistance of the triboelectric nanogenerator according to an embodiment of the present invention.
10 is a graph showing the open circuit voltage of a triboelectric nanogenerator according to an embodiment of the present invention optimized with PI:rGO.
11 is a graph showing electrical characteristics of a charging process of a triboelectric nanogenerator according to an embodiment of the present invention.
12A and 12B are enlarged graphs of electrical characteristics of a charging process using a triboelectric nanogenerator according to an embodiment of the present invention shown in FIG. 11 .
13A to 13D are images showing a red LED and a green LED driven by a triboelectric nanogenerator according to an embodiment of the present invention.
14a to 14f are graphs illustrating electrical characteristics during a sliding process of a triboelectric nanogenerator according to an embodiment of the present invention.
15 is a three-dimensional view of a triboelectric nanogenerator according to another embodiment of the present invention.
Figure 16a is a view showing a single layer manufacturing process of molybdenum disulfide (MOS ₂ ).
16B shows a scanning electron microscope measurement image of a monolayer of molybdenum disulfide.
16C shows an atomic force microscope (AFM) measurement image of a cross-section of a molybdenum disulfide monolayer formed on a silicon substrate.
16D shows a transmission electron microscopy (TEM) measurement image of a cross-section of a molybdenum disulfide monolayer.
16E shows a high-magnification transmission electron microscopy (TEM) measurement image of a monolayer of molybdenum disulfide.
FIG. 17 shows a scanning electron microscope measurement image of a cross section of a second layer (PI:MoS2) of a negative friction layer included in a triboelectric nanogenerator according to another embodiment of the present invention.
18A is a graph showing the open-circuit voltage of a triboelectric nanogenerator that does not contain PI:MoS2, and FIG. 18B is a graph showing the open-circuit voltage of a triboelectric nanogenerator according to another embodiment of the present invention.
FIG. 18C is an image showing the amount of charge and short-circuit current density generated during the friction-separation period of a triboelectric nanogenerator according to another embodiment of the present invention.
18D is a graph showing electrical characteristics of a charging process of a triboelectric nanogenerator according to another embodiment of the present invention.
18E is a graph showing output peak current versus output peak voltage of a triboelectric nanogenerator according to another embodiment of the present invention.
18F is an image showing an LCD and a green LED operated using a triboelectric nanogenerator according to another embodiment of the invention.
19A is a three-dimensional view illustrating a floating gate MIS including PI:MoS ₂ .
19B is a graph showing the capacitance of a floating gate MIS including PI:MoS ₂ .
19C is a graph showing a voltage-capacitance curve of a floating gate MIS including PI:MoS2 at a dual voltage sweep from -3V to 3V.
19D to 19G are diagrams illustrating energy bands of a floating gate MIS including PI:MoS ₂ .
20A is a cross-sectional view showing an operating mechanism of a triboelectric nanogenerator according to another embodiment of the present invention.
FIG. 20B is a graph showing the open circuit output voltage before and after charging of a triboelectric nanogenerator that does not contain PI:MoS ₂ , and FIG. It is a graph showing the open circuit output voltage.
FIG. 20D is a graph showing the short-circuit current of a triboelectric nanogenerator without PI:MoS ₂ and a triboelectric nanogenerator according to another embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings and the contents described in the accompanying drawings, but the present invention is not limited or limited by the embodiments.

Terminology used herein is for describing the embodiments and is not intended to limit the present invention. In this specification, singular forms also include plural forms unless specifically stated otherwise in a phrase. As used herein, "comprises" and/or "comprising" means that a stated component, step, operation, and/or element is present in the presence of one or more other components, steps, operations, and/or elements. or do not rule out additions.

As used herein, “embodiments,” “examples,” “aspects,” “examples,” and the like should not be construed as indicating that any aspect or design described is preferred or advantageous over other aspects or designs. It is not.

Also, the term 'or' means 'inclusive or' rather than 'exclusive or'. That is, unless otherwise stated or clear from the context, the expression 'x employs a or b' means any one of the natural inclusive permutations.

Also, the singular expressions “a” or “an” used in this specification and claims generally mean “one or more,” unless indicated otherwise or clear from context to refer to the singular form. should be interpreted as

The terms used in the description below have been selected as general and universal in the related technical field, but there may be other terms depending on the development and / or change of technology, convention, preference of technicians, etc. Therefore, terms used in the following description should not be understood as limiting technical ideas, but should be understood as exemplary terms for describing the embodiments.

In addition, in certain cases, there are also terms arbitrarily selected by the applicant, and in this case, their meanings will be described in detail in the corresponding description section. Therefore, terms used in the following description should be understood based on the meaning of the term and the contents throughout the specification, not simply the name of the term.

Meanwhile, terms such as first and second may be used to describe various components, but the components are not limited by the terms. Terms are used only to distinguish one component from another.

In addition, when a part of a film, layer, region, composition request, etc. is said to be "on" or "on" another part, not only when it is directly above the other part, but also when another act, layer, region, component in the middle thereof The case where the etc. are interposed is also included.

Unless otherwise defined, all terms (including technical and scientific terms) used in this specification may be used in a meaning commonly understood by those of ordinary skill in the art to which the present invention belongs. In addition, terms defined in commonly used dictionaries are not interpreted ideally or excessively unless explicitly specifically defined.

Meanwhile, in describing the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the gist of the present invention, the detailed description will be omitted. In addition, the terminology used in this specification is a term used to appropriately express the embodiment of the present invention, which may vary according to the intention of a user or operator or customs in the field to which the present invention belongs. Therefore, definitions of these terms will have to be made based on the content throughout this specification.

Hereinafter, a triboelectric nanogenerator according to embodiments of the present invention will be described with reference to FIG. 1 .

Referring to FIG. 1 , it is a cross-sectional view showing a triboelectric nanogenerator according to embodiments of the present invention.

The triboelectric nanogenerator according to embodiments of the present invention includes a lower electrode 120 formed on a first substrate 111, a negative friction layer 130 formed on the lower electrode 120, and a second substrate ( 112) and formed between the positive friction layer 140 used as an upper electrode and the first substrate 111 and the second substrate 1112, the first substrate 111 and the second substrate 112 ) includes at least one spacer maintaining a gap between

In addition, the negative friction layer 130 includes a polymer material and a nanomaterial, and the nanomaterial includes electrons and negative friction layer 130 generated in the negative friction layer by friction between the negative friction layer and the positive friction layer. ) to prevent recombination between adsorbed cations on the surface.

In addition, electrons generated in the negative friction layer 130 due to friction between the negative friction layer 130 and the positive friction layer 140 may be trapped in the nanomaterial.

Therefore, in the triboelectric nanogenerator according to embodiments of the present invention, electrons generated in the negative friction layer 130 due to friction between the negative friction layer 130 and the positive friction layer 140 are trapped in nanomaterials. As a result, generated electrons are prevented from recombination with cations absorbed on the surface of the negative friction layer 130, and electrons are prevented from being spontaneously lost by combining with particles in the air or absorbed charges, thereby forming a triboelectric nanogenerator. of power efficiency can be improved.

A triboelectric nanogenerator according to embodiments of the present invention includes a lower electrode 120 formed on a first substrate 111 .

The first substrate 111 may be formed to be spaced apart from the second substrate 112 at regular intervals, the first substrate 111 is a lower substrate, and the material of the first substrate 111 is not particularly limited, A commonly used substrate material may be used.

Preferably, the first substrate 111 may be a metal substrate or a polymer substrate, for example, the first substrate 111 may include a hard material such as a silicon wafer or glass, but is not necessarily limited thereto However, the first substrate 111 may include a flexible material such as polyethylene terephthalate (PET), polyester (PE), polyester sulfone (PES), polyethylene naphthalate (PEN), or Kapton. .

Depending on the embodiment, the first substrate 111 may be used as the lower electrode 120 .

The lower electrode 120 may be formed on the upper surface of the first substrate 111 , and the lower electrode 120 may include a material having excellent electrical conductivity.

For example, the lower electrode 120 may include at least one of graphene, carbon nanotube (CNT), indium tin oxide (ITO), a metal, and a conductive polymer, and the metal is, for example, For example, it may include at least one of Ag, Al, Cu, Au, Ni, Cr, and Pt, but is not limited thereto.

Also, the lower electrode 120 may have a single-layer structure or a multi-layer structure.

A triboelectric nanogenerator according to embodiments of the present invention includes a negative friction layer 130 formed on the lower electrode 120 .

The negative friction layer 130 may rub against the positive friction layer 140 of a different kind by an external force to induce triboelectricity. Here, the negative friction layer 130 is interposed between the lower electrode 120 and the upper electrode 140 and may include a polymer material or a nano material.

The nanomaterial can prevent recombination between electrons generated in the negative friction layer 130 by friction between the negative friction layer 130 and the positive friction layer 140 and positive ions absorbed on the surface of the negative friction layer. .

In addition, electrons generated in the negative friction layer 130 due to friction between the negative friction layer 130 and the positive friction layer 140 may be trapped in the nanomaterial.

Therefore, in the triboelectric nanogenerator according to embodiments of the present invention, electrons generated in the negative friction layer 130 due to friction between the negative friction layer 130 and the positive friction layer 140 are trapped in nanomaterials. As a result, generated electrons are prevented from recombination with cations absorbed on the surface of the negative friction layer 130, and electrons are prevented from being spontaneously lost by combining with particles in the air or absorbed charges, thereby forming a triboelectric nanogenerator. of power efficiency can be improved.

The negative friction layer 130 is a sandwich including a first layer 121 including a polymer material, a second layer 122 including a polymer material and a nanomaterial, and a third layer 123 including a polymer material. structure can be formed.

Therefore, the triboelectric nanogenerator according to embodiments of the present invention includes the negative friction layer 130 having a sandwich structure, so that the nanomaterial included in the second layer 122 of the negative friction layer is mixed with the polymer material. The performance of the triboelectric nanogenerator can be further improved by reducing the contact area between the electrodes to avoid the problem of reducing the electron density.

Also, according to an embodiment, the negative friction layer 130 includes a first layer 121 including a polymer material, a second layer 122 including a nano material, and a third layer 123 including a polymer material. can include

In addition, the negative friction layer 130 may be dispersed on the surface of a polymer thin film containing a polymer material. Thus, nanomaterials may have a form scattered on the polymer thin film.

In addition, the number of electrons trapped in the negative friction layer 130 can be controlled by the thickness of the negative friction layer 130 and the concentration of the nanomaterial.

More specifically, as the thickness of the negative friction layer 130 increases, more electrons can be trapped, so the number of electrons trapped in the negative friction layer 130 can increase.

In addition, as the concentration of the nanomaterial in the negative friction layer 130 increases, more electrons can be trapped, so the number of electrons trapped in the negative friction layer 130 can increase.

In addition, the nanomaterial included in the negative friction layer 130 traps electrons even in the process of moving electrons from the upper electrode 140 to the lower electrode 120 due to strong electron trapping properties and a large surface area. It is possible to improve the efficiency of triboelectric nanogenerators according to them.

The polymer material may include at least one of polytetrafluoroethylene, polydimethylsiloxane, polyvinyl chloride, polyimide, polypropylene, and polystyrene, and preferably, Kapton may be used as the polymer material.

The nanomaterial may include at least one of nanoparticles, single-layer crystals, multi-layer crystals, quantum dots, core-shell quantum dots, nanowires, nanoripples, nanotubes, nanorods, nanosheets, nanofibers, aerogels, and nanofoams. have.

Nanoparticles are Au, Al, In, Ga, Ag, AuCl ₃ , reduced graphene oxide (rGO), graphene, single-wall CNT, double-wall carbon nanotube -wall CNT) and at least one of Ni _x Fe _1-x .

Single-layer and multi-layer crystals are composed of molybdenum disulfide (MoS ₂ ), molybdenum diselenide (MoSe ₂ ), boron nitride (BN), graphene (grapheme), molybdenum telluride (MoTe), mica (Mica), and iteluride. At least one of molybdenum (MoTe ₂ ) and black phosphorus may be included.

Quantum dots are Si, Ge, GaAs, InP, InAs, AlAs, InSb, AlGa _x As _{1 -x} , InGaxAs1-x, CdSe, CdTe, ZnSe, ZnTe, CdTe _x Se _{1 -x} , HgTe, HgCd _x Te _{1 -x} , ZnO, GaN, Al _x Ga _{1 - x} N, SnO ₂ , CuO, Cu2O, C ₆ 0, Cu ₂ ZnSnS ₄ , CuInS ₂ , SrTiO ₃ , BaTiO ₃ , (Ga _{1 - x} Mn _x )N, (In _{1 - x} Mn _x ) N, CsPbCl ₃ , CdTe/ZnTe, may include at least one of.

Core-shell quantum dots are CdSe/CdTe, CdSe/CdS, InP/GaAs, CuInS4/ZnTe, CuInS2/CdS, CdSe/ZnS, Cd _{1 - x} ZnTe/ZnTe, GaAs/Si, ZnSe/GaAs, CuInS2/ZnS, Si / Si _x Ge _1-x , Au/SiO ₂ , InAs/GaAs, InP/GaAs/InAs, and CdSe/CdS/ZnS may include at least one.

The nanowire may include at least one of CeO ₂ , CdTe, ZnTe, SiO ₂ , Al ₂ O ₃ , ZnO, GaN, TiO ₂ , SnO ₂ , CuO, CuO ₂ , and CH ₃ NH ₃ PbI ₃ .

The nanorod may include at least one of CeO ₂ , CdTe, ZnTe, ZnO, GaN, TiO ₂ , SnO ₂ , CuxO, and CuO ₂ .

The nanoripple may include at least one of CeO ₂ , CdTe, ZnTe, ZnO, GaN, TiO ₂ , SnO ₂ , CuxO, and CuO ₂ .

The nanotube may include at least one of CeO ₂ , CdTe, ZnTe, ZnO, GaN, TiO ₂ , SnO ₂ , CuxO, and CuO ₂ .

Preferably, reduced graphene oxide or molybdenum disulfide may be used as the nanomaterial.

A technique in which graphene oxide or molybdenum disulfide reduced as a nanomaterial is used in a triboelectric nanogenerator according to an embodiment of the present invention will be described in detail with reference to FIGS. 2A to 20D.

Therefore, the nanomaterial included in the negative friction layer 130 of the triboelectric nanogenerator according to embodiments of the present invention generates negative friction by friction between the negative friction layer 130 and the positive friction layer 140. Electrons generated in the layer 130 are prevented from recombination with positive ions absorbed on the surface of the negative friction layer 130, thereby improving the power density and output voltage of the triboelectric nanogenerator.

A triboelectric nanogenerator according to an embodiment of the present invention includes a positive friction layer 140 formed on a second substrate and used as an upper electrode.

The second substrate 112 may be formed to be spaced apart from the first substrate 111 at regular intervals, the second substrate 112 is an upper substrate, and the material of the second substrate 112 is not particularly limited, A commonly used substrate material may be used.

Preferably, the second substrate 112 may be a metal substrate or a polymer substrate, and for example, the second substrate 112 may include a silicon wafer or a hard material such as glass, but is not necessarily limited thereto Alternatively, the second substrate may include a flexible material such as polyethylene terephthalate (PET), polyester (PE), polyester sulfone (PES), polyethylene naphthalate (PEN), or Kapton.

Depending on the embodiment, the second substrate 112 may be used as a positive friction layer (upper electrode) 140 .

A positive friction layer (upper electrode) 140 may be formed on the upper surface of the first substrate 112 , and the upper electrode 140 may include a material having excellent electrical conductivity.

For example, the positive friction layer (upper electrode, 140) may include at least one of graphene, carbon nanotube (CNT), indium tin oxide (ITO), metal, and conductive polymer. And, the metal may include, for example, at least one of Ag, Al, Cu, Au, Ni, Cr, and Pt, but is not limited thereto.

Also, the positive friction layer (upper electrode, 140) may have a single-layer structure or a multi-layer structure.

The triboelectric nanogenerator according to embodiments of the present invention includes at least one spacer formed between the first substrate 1111 and the second substrate 112 and maintaining a distance between the first substrate and the second substrate. do.

The spacer may be formed of a spring or a polymer material, and may be formed with an appropriate thickness to space the negative friction layer 130 and the positive friction layer 140 apart.

Preferably, a spring may be used as the spacer, and at least one spacer may be included at an edge portion between the first substrate 111 and the second substrate 112 .

In the triboelectric nanogenerator according to an embodiment of the present invention, since there is no potential difference between the lower electrode 120 and the upper electrode 140 in the basic state, the negative friction layer 130 and the positive friction layer 140 respectively It is possible to maintain a state in which there is no charge on the surface.

However, when an external force is applied to the triboelectric nanogenerator according to an embodiment of the present invention and the negative friction layer 130 and the positive friction layer 140 rub against each other, the negative friction layer ( 130) and the positive friction layer 140, charges may be transferred to each surface.

According to the triboelectric series, the negative friction layer 130 has a strong frictional polarity, and negative and positive charges can be induced on the surfaces of the negative friction layer 130 and the positive friction layer 140, respectively.

In addition, in the triboelectric nanogenerator according to an embodiment of the present invention, when the negative friction layer 130 and the positive friction layer 140 are separated again, the dipole moment becomes stronger, and the lower electrode 120 and the upper electrode A strong potential difference may be generated between (140). Thus, electrons flow from a negative potential to a positive potential, resulting in a triboelectric generator.

Triboelectric nanogenerators according to embodiments of the present invention may be used in generators, self-powered electronic devices, or wearable devices.

A method for manufacturing a triboelectric nanogenerator according to embodiments of the present invention includes forming a lower electrode on a first substrate, forming a negative friction layer on the lower electrode, and forming an upper electrode on a second substrate. and forming at least one spacer formed between the first substrate and the second substrate and maintaining a distance between the first substrate and the second substrate.

Since the method of manufacturing a triboelectric nanogenerator according to embodiments of the present invention includes the same components as the triboelectric nanogenerator according to embodiments of the present disclosure shown in FIG. 1 , the same components will be omitted.

In the method for manufacturing a triboelectric nanogenerator according to embodiments of the present invention, a lower electrode is formed on a first substrate.

The lower electrode is formed on the first substrate, and the lower electrode is formed by thermal deposition, vacuum deposition, chemical vapor deposition, physical vapor deposition, atomic layer deposition ( atomic layer deposition), Metal Organic Chemical Vapor Deposition, Plasma-Enhanced Chemical Vapor Deposition, Molecular Beam Epitaxy, Hydride Vapor Phase Epitaxy, It may be formed using at least one of sputtering, spin coating, dip coating, and zone casting.

A method for manufacturing a triboelectric nanogenerator according to embodiments of the present invention forms a negative friction layer on a lower electrode.

Also, depending on embodiments, a negative friction layer may be separately formed and attached to the lower electrode.

The negative friction layer includes a polymer material and a nano material, and the nano material is used between electrons generated in the negative friction layer and positive ions absorbed by the surface of the negative friction layer due to friction between the negative friction layer and the positive friction layer. prevent recombination.

Forming the negative friction layer may include forming a first layer including a polymer material on the lower electrode, forming a second layer including a polymer material and a nano material on the first layer, and A step of forming a third layer including a polymeric material on the layer may be included.

In particular, the step of forming a second layer including a polymer material and a nanomaterial is performed by adding a nanomaterial to a polymer material solution containing a polymer precursor and a solvent to form a nanomaterial uniformly dispersed in the polymer material, A layer solution may be prepared and then coated onto the first layer.

In addition, when a single-layer crystal is used as the negative friction layer, an exfoliation process is performed to exfoliate the multi-layer crystal into a single-layer crystal to prepare a single-layer crystal, and then the polymer precursor and the solvent are added into a polymer material solution. to prepare a second layer solution, which can then be coated on the first layer.

The negative friction layer can be applied by dip coating, drop-casting, spin-coating, bar coating, spray coating, spin coating, brush It may be formed by at least one method of brush coating, dip coating, and gravure coating.

In the method for manufacturing a triboelectric nanogenerator according to embodiments of the present invention, a positive friction layer used as an upper electrode is formed on a second substrate.

The positive friction layer can be formed by deep thermal deposition, vacuum deposition, chemical vapor deposition, physical vapor deposition, atomic layer deposition, or organometallic chemical vapor deposition. Metal Organic Chemical Vapor Deposition, Plasma-Enhanced Chemical Vapor Deposition, Molecular Beam Epitaxy, Hydride Vapor Phase Epitaxy, Sputtering, Spin Coating ( spin coating), dip coating, and zone casting.

In the method of manufacturing a triboelectric nanogenerator according to embodiments of the present invention, at least one spacer maintaining a distance between a first substrate and a second substrate is formed.

A spring may be used as the spacer, a spring wire having elasticity may be used as the spring, and the spring may be at least one of carbon steel, low-alloy steel, and spring steel. can include

Hereinafter, a triboelectric nanogenerator using reduced graphene oxide as a nanomaterial according to an embodiment of the present invention will be described with reference to FIGS. 2A to 14E.

2a is a diagram showing a three-dimensional view of a triboelectric nanogenerator according to an embodiment of the present invention.

Since FIG. 2A includes the same components as those in FIG. 1 , the same components will be omitted.

A triboelectric nanogenerator according to an embodiment of the present invention includes a lower electrode 210 formed on a first substrate, a negative friction layer 220 formed on the lower electrode 210, and a second substrate. , a positive friction layer 230 used as an upper electrode, and at least one spacer formed between the first substrate and the second substrate and maintaining a distance between the first substrate and the second substrate.

Preferably, aluminum (Al) may be used as the lower electrode 210 and the upper electrode 230, and polyimide (PI) may be used as a polymer material included in the negative friction layer 220, As the nanomaterial, reduced graphene oxide (rGO) may be used.

In particular, as the negative friction layer 220 of the triboelectric nanogenerator according to an embodiment of the present invention, the first layer 221 including polyimide and the second layer including polyimide and reduced graphene oxide ( 223) and the third layer 223 including polyimide may be sequentially stacked.

In addition, the negative friction layer 220 is prepared by combining functionalized graphene oxide (GO) sheets in a solution containing polyacrylamide (PAA) so that reduced graphene oxide can be uniformly dispersed in polyimide. It can be.

Therefore, the second layer 223 can be easily prepared by spin-coating a second layer solution containing graphene oxide functionalized with polyacrylamide and subsequent imidation.

In addition, the triboelectric nanogenerator according to an embodiment of the present invention does not affect the chemical structure of polyimide at all even if the second layer includes the reduced graphene oxide sheet.

The second layer 223 will be described in detail with reference to FIG. 2B.

FIG. 2b shows a second layer of the negative friction layer of a triboelectric nanogenerator according to an embodiment of the present invention.

Referring to FIG. 2B, the second layer of the negative friction layer includes polyimide and reduced graphene oxide, and more preferably, a reduced graphene oxide (rGO) sheet in a polyimide matrix (PI matrix) can be evenly distributed.

Also, the reduced graphene oxide (rGO) sheet included in the second layer of the negative friction layer can trap electrons.

manufacturing example

Preparation of PAA:GO solution

Graphene oxide (GO) sheets were prepared by purifying native graphite by using a modified Hummers method. A PAA precursor solution made by dissolving polyamic acid (PAA) in dimethylformamide (DMF) was obtained by dissolving 287.5 mg of p-phenylenediamine (PDA) and 781.25 mg of biphenyldianhydride (BPDA) in a DMF solution. did

A PAA:GO mixture was obtained by adding the GO sheet to the PAA precursor solution and ultrasonicating for 1 hour, and preparing a PAA and PAA:GO solution in which the GO sheet was uniformly dispersed in the PAA precursor solution.

TENG device manufacturing

To fabricate the negative friction layer of TENG, an Al film was deposited on a glass substrate using a thermal evaporation method to form a lower electrode. Thereafter, a PAA precursor solution was coated to form a first layer of a negative friction layer of a PI (Kapton) film, and a PAA:GO film was coated on the PI (Kapton) film by a spin coating method, and heat treatment was performed at 135 ° C. for 30 minutes. The solvent was evaporated to form a second layer of negative friction layer, and a PAA precursor solution was coated on the second layer of negative friction layer to form a third layer of negative friction layer of PI (Kapton) film.

Thereafter, heat treatment was performed at 400° C. for 2 hours to form a negative friction layer in which PI (Kapton)/Pi:rGO/PI were sequentially stacked and attached to the lower electrode. Finally, an aluminum (Al) foil-attached glass substrate was prepared as a positive friction layer, and the positive friction layer was supported by a 10 mm thick spring used as a TENG space layer and attached to the negative friction layer.

3 shows an optical image of a triboelectric nanogenerator according to an embodiment of the present invention.

Referring to FIG. 3 , it can be seen that the triboelectric nanogenerator according to an embodiment of the present invention has an active size of 1.5 cm×2.5 cm.

4 shows a scanning electron microscope (SEM) measurement image of a cross section of a negative friction layer included in a triboelectric nanogenerator according to an embodiment of the present invention.

Referring to FIG. 4 , the negative friction layer of the triboelectric nanogenerator according to an embodiment of the present invention is composed of polyimide (PI), polyimide and reduced graphene oxide (PI:rGO), and polyimide (PI). It can be seen that they are sequentially stacked well.

In addition, it can be seen that the reduced graphene oxide (rGO) is uniformly dispersed in the polyimide (PI) in the second layer (PI:rGO) of the negative friction layer of the triboelectric nanogenerator according to an embodiment of the present invention. can

5A to 5D are graphs showing open-circuit voltages of triboelectric nanogenerators according to an embodiment of the present invention.

FIG. 5A is an open-circuit voltage in a triboelectric nanogenerator including only the first layer as a negative friction layer, and FIG. 5B is only the first layer (Kapton) and the polymer material (PI) as the second layer. Figure 5c is a triboelectric according to an embodiment of the present invention including a first layer (Kapton) and a second layer (PI: rGO) as negative friction layers. Open-circuit voltage in the nanogenerator, Figure 5d is an open-circuit voltage in the triboelectric nanogenerator according to an embodiment of the present invention including the first layer (Kapton) to the third layer (PI) as the negative friction layer. is the circuit voltage.

In addition, FIGS. 5A and 5B sequentially show the open-circuit voltage at an activation process, an operating frequency of 0.2 Hz, an operating frequency of 1 Hz, and an operating frequency of 7 Hz.

5A to 5D show that the triboelectric nanogenerator according to an embodiment of the present invention including first to third layers as negative friction layers undergoes 40 friction-separation cycles to obtain a stable voltage output. , it can be seen that the friction-separation period to have a stable contact pressure output is reduced compared to the triboelectric nanogenerator containing only a polymer material in the negative friction layer.

In addition, the triboelectric nanogenerator according to an embodiment of the present invention including the first to third layers as negative friction layers at an operating frequency of 7 Hz has a lower friction than the triboelectric nanogenerator including only polymer materials in the negative friction layer. It can be seen that it represents an output voltage of 90V, which is about three times higher.

In addition, the output voltage of the triboelectric nanogenerator including only polymer materials in the negative friction layer increases as the operating frequency increases, but the negative friction layer includes the first to third layers according to an embodiment of the present invention. The triboelectric nanogenerator according to has an output voltage that does not depend on the operating frequency and exhibits a high output voltage, indicating that the triboelectric nanogenerator according to an embodiment of the present invention exhibits stable operating characteristics.

6A to 6F show graphs and energy bands illustrating electron trap mechanisms.

FIG. 6a is an excitation spectrum (left) and an emission spectrum (right) of a polyimide (hereinafter referred to as PI) and a polyimide:reduced graphene oxide (hereinafter referred to as PI:rGO) nanocomposite. ) is a graph showing.

Referring to FIG. 6a, it can be seen that fluorescence excitation occurs at a wavelength of around 361 nm in the PI:rGO nanocomposite.

Therefore, as the fluorescence excitation of the PI:rGO nanocomposite is higher than that of PI, rGO (more preferably rGO sheet) can promote the charge transfer process, through which rGO can trap charges. know what can be

6B is a graph showing absorption spectra of PI and PI:rGO nanocomposites, respectively.

Referring to FIG. 6B, it can be seen that the absorption peak in the visible light region of the PI:rGO nanocomposite is shifted from 544 nm to 572 nm by rGO.

6C is a graph showing capacitance of a floating-gate metal-insulator-semiconductor (MIS) including a PI:rGO nanocomposite.

6c shows the electron transfer and trapping effect of the PI:rGO nanocomposite by introducing the PI:rGO nanocomposite as the charge storage layer of the floating gate MIS, and the voltage-capacitance (C-V) curve was measured at 5 MHz.

Referring to FIG. 6C , as the maximum negative bias increases in the voltage-capacitance hysteresis window (C-V hysteresis windows), it can be seen that the rGO dispersed in the PI traps electrons to increase the charge capture.

6D is a graph showing flat-band voltage shifts (ΔVfb) of the floating gate MIS according to various applied voltages.

Referring to FIG. 6D , the average density of electrons trapped at negative bias is 3.8×10 ^-3 C/m ² to 2.8×10 ^-2 C/m ² when the negative applied voltage is increased from -1V to -8V. It can be seen that increases up to

6E shows an energy band diagram of the floating gate MIS at zero bias, and FIG. 6F shows an energy band diagram of the floating gate MIS at a negative bias.

Referring to FIG. 6E , it can be seen that when the voltage applied to the upper electrode is 0V, charges are not trapped in the PI:rGO charge storage layer.

However, referring to FIG. 6F, when a negative voltage is applied to the upper electrode, electrons are injected from the Fermi level of the upper electrode to the lowest unoccupied molecular orbital (LUMO) level, and then rCO of the PI:rGO charge storage layer. It can be seen that it is trapped in .

When electrons are trapped in the PI:rGO charge storage layer, holes are accumulated at the PI/p-Si interface, increasing the capacitance value, which is similar to the operating principle of triboelectric nanogenerators.

7A is a graph showing an open circuit voltage according to a thickness of a second layer (PI:rGO) included in a triboelectric nanogenerator according to an embodiment of the present invention.

Referring to FIG. 7A , as the thickness of the second layer (PI:rGO) included in the triboelectric nanogenerator according to an embodiment of the present invention increases, the open circuit voltage increases, and in particular, the second layer (PI:rGO) increases. It can be seen that the open circuit voltage increases to 150V when the thickness of ) is increased to 6.5 μm.

FIG. 7B is a graph showing the open circuit voltage according to the rGO concentration of the second layer (PI:rGO) included in the triboelectric nanogenerator according to an embodiment of the present invention.

Referring to FIG. 7B , as the rGO concentration of the second layer (PI: rGO) included in the triboelectric nanogenerator according to an embodiment of the present invention increases, the open circuit voltage increases, and in particular, the second layer (PI: rGO) increases. When the concentration of rGO in :rGO) is about 20.0 wt%, the maximum open-circuit output voltage increases to 190 V, which is about 7 times higher than that of the triboelectric nanogenerator without rGO.

However, in the triboelectric nanogenerator according to an embodiment of the present invention, when the concentration of rGO in the second layer (PI:rGO) increases to about 28.9 wt%, the rGO is connected to each other by the high concentration of rGO. It can be seen that the lower part of the second layer (PI:rGO) has an effect of shielding the internal electric field, and thus the open circuit voltage is reduced to 50V.

8 is a graph showing output voltage and current density according to external loading resistance of a triboelectric nanogenerator according to an embodiment of the present invention.

Referring to FIG. 8 , it can be seen that the output voltage of the triboelectric nanogenerator according to an embodiment of the present invention decreases as the external load resistance increases.

In addition, it can be seen that the triboelectric nanogenerator according to an embodiment of the present invention has improved output characteristics and improved current density than the triboelectric nanogenerator that does not contain PI:rGO.

9 is a graph showing output power density according to external load resistance of a triboelectric nanogenerator according to an embodiment of the present invention.

Referring to FIG. 9 , it is seen that the output power density of the triboelectric nanogenerator according to an embodiment of the present invention reaches a maximum value of 6.3 W/m ² at a resistance of about 5 MΩ. It can be seen that the triboelectric nanogenerator according to this method has a 300-fold increase in output power density compared to the triboelectric nanogenerator without PI:rGO.

Therefore, it can be seen that the output characteristics of the triboelectric nanogenerator according to an embodiment of the present invention are improved compared to the triboelectric nanogenerator that does not contain PI:rGO.

10 is a graph showing the open circuit voltage of a triboelectric nanogenerator according to an embodiment of the present invention optimized with PI:rGO.

When an energy storage device is charged using a triboelectric nanogenerator according to an embodiment of the present invention optimized with PI:rGO, the AC signal is rectified before connecting to a load.

As shown in FIG. 10, the output voltage of the triboelectric nanogenerator according to an embodiment of the present invention optimized with PI:rGO can be rectified by a rectifier bridge circuit.

11 is a graph showing electrical characteristics of a charging process of a triboelectric nanogenerator according to an embodiment of the present invention.

As shown in FIG. 11, a capacitor was charged using a triboelectric nanogenerator according to an embodiment of the present invention, and a 0.22 μF capacitor was charged using a triboelectric nanogenerator according to an embodiment of the present invention at an operating frequency of 7 Hz. has been charged

12A and 12B are enlarged graphs of electrical characteristics of a charging process using a triboelectric nanogenerator according to an embodiment of the present invention shown in FIG. 11 .

Referring to FIG. 12A, the triboelectric nanogenerator according to an embodiment of the present invention is charged in a shorter time than the triboelectric nanogenerator that does not contain PI:rGO, indicating that the charging performance is improved.

In particular, the triboelectric nanogenerator according to an embodiment of the present invention charged the capacitor to 6V in just 7 seconds.

In addition, the triboelectric nanogenerator according to an embodiment of the present invention can charge the capacitor in both press and release operations because the signal is rectified.

During the friction operation of the triboelectric nanogenerator according to an embodiment of the present invention, the voltage of the charged capacitor increased to 0.32 V, which was almost the same as the separation operation. However, the triboelectric nanogenerator without PI:rGO only increased the voltage by about 0.1 V.

Referring to FIG. 12B, the triboelectric nanogenerator according to an embodiment of the present invention has a total accumulation amount of about 0.16 μC during the triboelectric nanogenerator, and the triboelectric nanogenerator that does not contain PI:rGO has a triboelectric nanogenerator that does not contain PI:rGO during the triboelectric separation period. It can be seen that the charging characteristics of the triboelectric nanogenerator according to an embodiment of the present invention are remarkably improved, considering that the total accumulation amount during the period is about 0.05 μC.

13A to 13D are images showing a red LED and a green LED driven by a triboelectric nanogenerator according to an embodiment of the present invention.

Referring to FIGS. 13A to 13D , it can be seen that 100 red LEDs and 100 green LEDs can be instantaneously turned on and off using the triboelectric nanogenerator according to an embodiment of the present invention.

14a to 14f are graphs illustrating electrical characteristics during a sliding process of a triboelectric nanogenerator according to an embodiment of the present invention.

14A is a three-dimensional view illustrating a horizontal sliding process of a triboelectric nanogenerator according to an embodiment of the present invention.

Referring to FIG. 14A, the triboelectric nanogenerator according to an embodiment of the present invention can be operated even when the negative friction layer and the positive friction layer slide, overcoming the limitation in vertical friction to obtain a triboelectric nanogenerator. efficiency can be maximized.

FIG. 14B is a graph showing the open circuit voltage during sliding of a triboelectric nanogenerator according to an embodiment of the present invention, and FIG. 14C is an open circuit during sliding of a triboelectric nanogenerator not containing PI:rGO. It is a graph showing voltage.

Referring to FIGS. 14b and 14c, it can be seen that the open-circuit voltage during the sliding process of the triboelectric nanogenerator according to an embodiment of the present invention increases by about 3 times compared to that of the triboelectric nanogenerator without PI:rGO. can

14D is a graph showing power density in a sliding process of a triboelectric nanogenerator according to an embodiment of the present invention.

Referring to FIG. 14D , it can be seen that the power density in the sliding process of the triboelectric nanogenerator according to an embodiment of the present invention reaches a maximum value of 0.3 W/M ² at a resistance of about 10 MΩ.

Therefore, it can be seen that the maximum power density in the sliding process of the triboelectric nanogenerator according to an embodiment of the present invention increases by about 9 times compared to that of the triboelectric nanogenerator without PI:rGO.

14E is a graph showing a charging process of a triboelectric nanogenerator according to an embodiment of the present invention using sliding.

Referring to FIG. 14E, the triboelectric nanogenerator according to an embodiment of the present invention using sliding at an operating frequency of 8 Hz charged the capacitor to 4.5 V in just 5 seconds.

14F is a graph showing accumulated charge of a triboelectric nanogenerator according to an embodiment of the present invention using sliding.

Referring to FIG. 14f , the triboelectric nanogenerator according to an embodiment of the present invention has PI: It can be seen that the efficiency is improved compared to the triboelectric nanogenerator without rGO.

Hereinafter, a triboelectric nanogenerator using molybdenum disulfide as a nanomaterial according to another embodiment of the present invention will be described with reference to FIGS. 15 to 20D.

15 is a three-dimensional view of a triboelectric nanogenerator according to another embodiment of the present invention.

Since FIG. 15 includes the same components as those of FIG. 1 and the triboelectric nanogenerator according to an embodiment of the present invention, the same components will be omitted.

A triboelectric nanogenerator according to another embodiment of the present invention includes a lower electrode 320 formed on a first substrate 311, a negative friction layer 330 formed on the lower electrode 320, and a second substrate ( 312) and formed between the positive friction layer 340 used as an upper electrode and the first substrate 311 and the second substrate 312, the first substrate 311 and the second substrate 312 ) includes at least one spacer maintaining a gap between

Preferably, aluminum (Al) may be used as the lower electrode 320 and the upper electrode 340, and polyimide (PI) may be used as a polymer material included in the negative friction layer 220, As the nanomaterial, molybdenum disulfide (MoS ₂ ) may be used. More preferably, the molybdenum disulfide may be a monolayer crystal.

Molybdenum disulfide monolayer crystal used as a nanomaterial has a very large specific surface area to which electrons are attached, so it can further improve the electron trap efficiency and further improve the performance of triboelectric nanogenerators. can

In particular, as the negative friction layer 330 of the triboelectric nanogenerator according to another embodiment of the present invention, the first layer 331 including polyimide, the second layer 332 including polyimide and molybdenum disulfide, and A sandwich structure in which the third layer 333 including polyimide is sequentially stacked may be formed.

In addition, the negative friction layer 340 is a single layer of molybdenum disulfide (MoS ₂ ) functionalized in a solution containing polyacrylamide (PAA) so that molybdenum disulfide (MoS ₂ ) can be uniformly dispersed in polyimide (PI). It can be made by combining layers.

In addition, the triboelectric nanogenerator according to another embodiment of the present invention does not affect the chemical structure of polyimide even if molybdenum disulfide (MoS ₂ ) is included in the negative friction layer 340 .

The second layer 332 of the negative friction layer includes polyimide and molybdenum disulfide, and more preferably, a monolayer MoS ₂ of molybdenum disulfide may be uniformly dispersed in a polyimide matrix (PI matrix).

Also, molybdenum disulfide included in the second layer 332 of the negative friction layer can trap electrons from the electrode.

manufacturing example

MoS ₂ monolayer manufacturing

A MoS ₂ monolayer was obtained by exfoliating the pieces of MoS ₂ using the same method as in FIG. 16a.

MoS ₂ Monolayer and PAA suspension solution preparation

A PAA precursor solution made by dissolving polyamic acid (PAA) in dimethylformamide (DMF) was obtained by dissolving 287.5 mg of p-phenylenediamine (PDA) and 781.25 mg of biphenyldianhydride (BPDA) in a DMF solution. did

10 mg of MoS ₂ powder was added to 20 ml of a PAA precursor solution and sonicated for 9 hours to prepare a MoS ₂ single layer PAA suspension. The resulting MoS ₂ monolayer PAA suspension was left alone for 7 days to remove residual particles, and then the supernatant on the surface was collected by centrifugation at 4000 rpm for 30 minutes, and the MoS ₂ monolayer was uniformly dispersed in the PAA precursor solution. A MoS ₂ monolayer PAA suspension solution was prepared.

TENG device manufacturing

To fabricate the negative friction layer of TENG, an Al film was deposited on a glass substrate using a thermal evaporation method to form a lower electrode. Thereafter, a PAA precursor solution was coated to form a first layer of a negative friction layer of a PI (Kapton) film, and a PAA;MoS ₂ film was coated on the PI (Kapton) film by a spin coating method, and heat treatment was performed at 135 ° C. for 30 minutes. The solvent was evaporated to form a second layer of negative friction layer, and a PAA precursor solution was coated on the second layer of negative friction layer to form a third layer of negative friction layer of PI (Kapton) film.

Thereafter, heat treatment was performed at 400° C. for 2 hours to form a negative friction layer in which PI (Kapton)/Pi:rGO/PI were sequentially stacked and attached to the lower electrode. Finally, an aluminum (Al) foil-attached glass substrate was prepared as a positive friction layer, and the positive friction layer was attached to the negative friction layer by supporting it with a 10 mm thick spring used as a TENG space layer.

Figure 16a is a view showing a single layer manufacturing process of molybdenum disulfide (MoS ₂ ).

Referring to FIG. 16A, a single layer of molybdenum disulfide (MoS ₂ ) was prepared by liquid phase exfoliation of bulk molybdenum disulfide powder contained in an organic solvent by ultrasonic waves.

In addition, a polyamic acid (PAA) precursor solution containing polyamic acid (PAA), which is a precursor of polyimide, was used.

A polyimide:molybdenum disulfide (PI:MoS ₂ ) layer was prepared by spin-coating and imidizing the solution prepared by adding a single layer of molybdenum disulfide (MoS ₂ ) to a polyamic acid (PAA) precursor solution.

16B shows a scanning electron microscope measurement image of a monolayer of molybdenum disulfide.

16b shows that the molybdenum monolayer is well separated from the molybdenum disulfide powder.

16C shows an atomic force microscope (AFM) measurement image of a cross-section of a molybdenum disulfide monolayer formed on a silicon substrate.

Referring to FIG. 16C , it can be seen that the molybdenum disulfide nanosheet having a length of several hundred nanometers has a thickness of about 1 nm.

16D shows a transmission electron microscopy (TEM) measurement image of a cross-section of a molybdenum disulfide monolayer.

Referring to FIG. 16D , it can be seen that the molybdenum disulfide single layer is a single crystal domain, as the selected area electron diffraction (SAED) pattern has hexagonal symmetry.

16E shows a high-magnification transmission electron microscopy (TEM) measurement image of a monolayer of molybdenum disulfide.

Referring to FIG. 16E, since the molybdenum disulfide single layer has a honeycomb structure, it can be seen that the release sheet of molybdenum disulfide is a single layer.

17 shows a scanning electron microscope measurement image of a cross section of a second layer of a negative friction layer included in a triboelectric nanogenerator according to another embodiment of the present invention.

Referring to FIG. 17 , it can be seen that in the triboelectric nanogenerator according to another embodiment of the present invention, the second layer of the negative friction layer (hereinafter referred to as PI: MoS ₂ ) is uniformly formed.

18A is a graph showing the open-circuit voltage of a triboelectric nanogenerator that does not contain PI:MoS ₂ , and FIG. 18B is a graph showing the open-circuit voltage of a triboelectric nanogenerator according to another embodiment of the present invention.

18a and 18b, the open circuit voltage of the triboelectric nanogenerator not containing PI:MoS ₂ is about 30V, but the open circuit voltage of the triboelectric nanogenerator according to another embodiment of the present invention is 400V, It can be seen that the open circuit voltage is greatly improved.

FIG. 18C is an image showing the amount of charge and short-circuit current density generated during the friction-separation period of a triboelectric nanogenerator according to another embodiment of the present invention.

Referring to FIG. 18C , it can be seen that the short-circuit current density of the triboelectric nanogenerator according to another embodiment of the present invention is improved compared to that of the triboelectric nanogenerator without PI:MoS ₂ .

In addition, the amount of charge generated during the friction-separation cycle of the triboelectric nanogenerator according to another embodiment of the present invention is improved by 0.05 μC, which is the amount of charge generated during the friction-separation cycle of the triboelectric nanogenerator not containing PI:MoS ₂ . represents 0.2 μC.

18D is a graph showing electrical characteristics of a charging process of a triboelectric nanogenerator according to another embodiment of the present invention.

18d shows that a capacitor was charged using a triboelectric nanogenerator according to another embodiment of the present invention, and a 0.22 μF capacitor was charged using a triboelectric nanogenerator according to another embodiment of the present invention at an operating frequency of 7 Hz.

Referring to FIG. 18D , it can be seen that the triboelectric nanogenerator according to another embodiment of the present invention is charged in a shorter time than the triboelectric nanogenerator that does not contain PI:MoS ₂ .

In particular, the triboelectric nanogenerator according to another embodiment of the present invention charged the capacitor up to 10V in just 15 seconds.

In addition, the triboelectric nanogenerator according to another embodiment of the present invention can charge the capacitor in both press and release operations because the signal is rectified.

During the friction operation of the triboelectric nanogenerator according to another embodiment of the present invention, the voltage of the charged capacitor increased to 0.5 V, which was almost the same as the separation operation. However, the triboelectric nanogenerator without PI:MoS ₂ increased the voltage by only about 0.1V.

18E is a graph showing output peak current versus output peak voltage of a triboelectric nanogenerator according to another embodiment of the present invention.

Referring to FIG. 18E, the rectangular area defined by the current-voltage curve determines the maximum peak power density, and the triboelectric nanogenerator according to another embodiment of the present invention has a resistance of about 5 MΩ of 25.7 W/M ² . The maximum peak power density is reached, which is a 120-fold increase over triboelectric nanogenerators without PI:rGO.

18F is an image showing an LCD and a green LED operated using a triboelectric nanogenerator according to another embodiment of the invention.

Referring to FIG. 18F , it can be seen that the triboelectric nanogenerator according to another embodiment of the present invention can be used as a direct power source for LCDs and green LEDs.

19A is a three-dimensional view illustrating a floating gate MIS including PI:MoS ₂ .

Referring to FIG. 19A, the floating gate MIS has a structure of Al/p-Si/PI/MoS ₂ :PI/PI/Al, and PI:MoS ₂ is introduced as a charge storage layer to transfer electrons of PI:MoS ₂ and The trapping effect was confirmed, and the electrical characteristics of the voltage-capacitance (CV) curve were measured at 5 MHz.

In addition, C-V measurements were performed by applying a dual voltage sweep from −3 V to 3 V.

19B is a graph showing the capacitance of a floating gate MIS including PI:MoS ₂ .

Referring to FIG. 19B , clockwise hysteresis is confirmed, indicating that PI:MoS ₂ is used as the charge trapping region.

In addition, it can be seen that the capacitance tendency of the floating gate MIS including PI:MoS ₂ is similar to that of the floating gate MIS including PI:rGO.

FIG. 19C is a graph showing a voltage-capacitance curve of a floating gate MIS including PI:MoS ₂ at a dual voltage sweep from -3V to 3V.

Referring to FIG. 19C , it can be seen that the number of electrons trapped in PI:MoS ₂ increases as the number of voltage sweeps increases.

19D to 19G are diagrams illustrating energy bands of a floating gate MIS including PI:MoS ₂ .

Referring to FIG. 19D , when a negative voltage is applied to the upper electrode, the floating gate MIS including PI:MoS ₂ maintains a flat band state so that electrons are not trapped in the PI:MoS ₂ charge storage layer.

Referring to FIG. 19E, when a higher negative voltage than that of FIG. 19D is applied to the upper electrode, electrons move to the lowest LUMO at the electrode and are trapped in the PI:MoS ₂ charge storage layer.

When the PI:MoS ₂ charge storage layer traps electrons, holes are accumulated at the PI/p-Si interface to increase the capacitance value, which is similar to the operating principle of a triboelectric nanogenerator.

Referring to FIG. 19F, when a positive voltage is applied to the upper electrode, electrons in a conduction band bottom energy state are emitted to the upper electrode, and electrons within the band gap are trapped at the interface.

Accordingly, referring to FIG. 19G , it can be seen that a smaller negative voltage is required in the flat-band condition.

Referring to FIGS. 19D to 19G , it can be seen that as the number of voltage sweeps increases, the number of electrons trapped in the PI:MoS ₂ charge storage layer increases and the voltage-capacitance curve also shifts.

20A is a cross-sectional view showing an operating mechanism of a triboelectric nanogenerator according to another embodiment of the present invention.

20a shows that the triboelectric nanogenerator according to another embodiment of the present invention has an active area of 1.5 cm × 2.5 cm.

Referring to FIG. 20A , in a triboelectric nanogenerator according to another embodiment of the present invention, some of the electrons on the surface of the negative friction layer are initially transferred to the second layer of the negative friction layer including PI:MoS ₂ .

When the positive friction layer gradually moves to the negative friction layer of the triboelectric nanogenerator according to another embodiment of the present invention, the positive charge of the lower electrode gradually moves to the upper electrode.

When the positive friction layer rubs against the negative friction layer of the triboelectric nanogenerator according to another embodiment of the present invention, electrons in the lower part move to the upper part because the electron-gaining ability is the same. .

However, the lower part of the triboelectric nanogenerator according to another embodiment of the present invention traps electrons by MoS ₂ and contains a larger number of electrons.

When the positive friction layer of the triboelectric nanogenerator according to another embodiment of the present invention is spaced apart again, the positive charge of the upper electrode is gradually transferred to the lower electrode during the separation process.

In addition, electrons present in the lower part of the triboelectric nanogenerator according to another embodiment of the present invention are moved to the positive friction layer and the negative friction layer.

Therefore, in the triboelectric nanogenerator according to another embodiment of the present invention, the open circuit voltage of the triboelectric nanogenerator is increased by trapping electrons by the negative friction layer including PI:MoS ₂ .

FIG. 20B is a graph showing the open circuit output voltage before and after charging of a triboelectric nanogenerator that does not contain PI:MoS ₂ , and FIG. It is a graph showing the open circuit output voltage.

Referring to FIGS. 20B and 20C, a triboelectric nanogenerator according to another embodiment of the present invention exhibits an open circuit voltage of about 120V, which is a significantly higher value than that of a triboelectric nanogenerator that does not contain PI:MoS ₂ . to be.

FIG. 20D is a graph showing the short-circuit current of a triboelectric nanogenerator without PI:MoS ₂ and a triboelectric nanogenerator according to another embodiment of the present invention.

Figure 20d measures the short-circuit current as a function of time at a frequency of 5 Hz.

Referring to FIG. 20D, the output current of the triboelectric nanogenerator (upper graph) not containing PI:MoS ₂ decreases as electrons are lost over time, whereas the triboelectric nanogenerator according to another embodiment of the present invention The output current in (lower graph) shows that MoS ₂ prevents electrons from being lost, indicating high stability of triboelectric nanogeneration.

On the other hand, the embodiments of the present invention disclosed in this specification and drawings are only presented as specific examples to aid understanding, and are not intended to limit the scope of the present invention. In addition to the embodiments disclosed herein, it is obvious to those skilled in the art that other modified examples based on the technical idea of the present invention can be implemented.

111, 311: first substrate 112, 312: second substrate
120, 210, 320: lower electrode 130, 220, 330: negative friction layer
131, 221, 331: first layer 132, 222, 332: second layer
133, 223, 333 third layer 140, 230, 340 positive friction layer, upper electrode

Claims (17)

a lower electrode formed on the first substrate;
a negative friction layer formed on the lower electrode;
a positive friction layer formed on the second substrate and used as an upper electrode; and
at least one spacer formed between the first substrate and the second substrate and maintaining a distance between the first substrate and the second substrate;
including,
the negative friction layer includes a first layer comprising polyimide, a second layer comprising the polyimide and a nanomaterial, and a third layer comprising the polyimide;
The nanomaterial prevents recombination between electrons generated in the negative friction layer and positive ions absorbed on the surface of the negative friction layer by friction between the negative friction layer and the positive friction layer. .
According to claim 1,
The triboelectric nanogenerator, characterized in that the generated electrons are trapped in the nanomaterial.
According to claim 2,
The triboelectric nanogenerator, characterized in that the number of electrons trapped is controlled by the thickness of the negative friction layer and the concentration of the nanomaterial.
According to claim 1,
The triboelectric nanogenerator, characterized in that the negative friction layer is dispersed on the surface of the polymer thin film containing the polyimide.
delete According to claim 1,
The nanomaterial includes at least one of nanoparticles, single-layer crystals, multi-layer crystals, quantum dots, core-shell quantum dots, nanowires, nanoripples, nanotubes, nanorods, nanosheets, nanofibers, aerogels, and nanofoams. A triboelectric nanogenerator, characterized in that.
According to claim 6,
The nanoparticles are Au, Al, In, Ga, Ag, AuCl ₃ , reduced graphene oxide, graphene, single-wall CNT, double-wall carbon nanotube wall CNT) and Ni _x Fe ₁ - _x triboelectric nanogenerator comprising at least one of.
According to claim 6,
The single-layer crystal and the multi-layer crystal are molybdenum disulfide (MoS ₂ ), molybdenum diselenide (MoSe ₂ ), boron nitride (BN), graphene, molybdenum telluride (MoTe), mica (Mica), and itelurium. A triboelectric nanogenerator comprising at least one of molybdenum (MoTe ₂ ) and black phosphorus.
According to claim 6,
The quantum dots are Si, Ge, GaAs, InP, InAs, AlAs, InSb, AlGa _x As _{1 -x} , InGaxAs1-x, CdSe, CdTe, ZnSe, ZnTe, CdTe _x Se _{1 -x} , HgTe, HgCd _x Te _{1 - x} , ZnO, GaN, Al _x Ga _{1 - x} N, SnO ₂ , CuO, Cu2O, C ₆ 0, Cu ₂ ZnSnS ₄ , CuInS ₂ , SrTiO ₃ , BaTiO ₃ , (Ga _{1 - x} Mn _x )N, ( A triboelectric nanogenerator comprising at least one of In _{1 - x} Mn _x )N, CsPbCl ₃ , and CdTe/ZnTe.
According to claim 6,
The core-shell quantum dots are CdSe / CdTe, CdSe / CdS, InP / GaAs, CuInS / ZnTe, CuInS / CdS, CdSe / ZnS, Cd _{1 - x} ZnxTe / ZnTe, GaAs / Si, ZnSe / GaAs, CuInS / ZnS, A triboelectric nanogenerator comprising at least one of Si/Si _x Ge _1-x , Au/SiO ₂ , InAs/GaAs, InP/GaAs/InAs, and CdSe/CdS/ZnS.
According to claim 6,
The nanowires include at least one of CeO ₂ , CdTe, ZnTe, SiO ₂ , Al ₂ O ₃ , ZnO, GaN, TiO ₂ , SnO ₂ , CuO, CuO ₂ and CH ₃ NH ₃ PbI ₃ triboelectric nanogenerators.
According to claim 6,
The triboelectric nanogenerator, characterized in that the nanorod includes at least one of CeO ₂ , CdTe, ZnTe, ZnO, GaN, TiO ₂ , SnO ₂ , CuxO and CuO ₂ .
According to claim 6,
The nanoripples include at least one of CeO ₂ , CdTe, ZnTe, ZnO, GaN, TiO ₂ , SnO ₂ , CuxO and CuO ₂ Triboelectric nanogenerator.
According to claim 6,
The nanotube triboelectric nanogenerator, characterized in that it contains at least one of CeO ₂ , CdTe, ZnTe, ZnO, GaN, TiO ₂ , SnO ₂ , CuxO and CuO ₂ .
delete forming a lower electrode on the first substrate;
forming a negative friction layer formed on the lower electrode;
forming a positive friction layer used as an upper electrode on a second substrate; and
Forming at least one spacer formed between the first substrate and the second substrate and maintaining a distance between the first substrate and the second substrate.
including,
The negative friction layer includes polyimide and nanomaterials,
The nanomaterial prevents recombination between electrons generated in the negative friction layer and positive ions absorbed by the surface of the negative friction layer due to friction between the negative friction layer and the positive friction layer,
forming a first layer including the polyimide on the lower electrode;
forming a second layer including the polyimide and nanomaterials on the first layer;
Forming a third layer comprising the polyimide on the second layer
A method for producing a triboelectric nanogenerator comprising a. delete

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