Bio-piezoelectric layer manufacturing method, bio-piezoelectric layer manufactured thereby, piezoelectric power generation device manufacturing method, and piezoelectric power generation device manufactured thereby

Abstract

Disclosed are a bio-piezoelectric layer manufacturing method, a bio-piezoelectric layer manufactured thereby, a piezoelectric power generation device manufacturing method, and a piezoelectric power generation device manufactured thereby. The present invention comprises the steps of: preparing a glycine solution by mixing a glycine powder and a second solvent into a first solvent; immersing a substrate in the glycine solution; and producing glycine crystals by pulling the substrate from the glycine solution.

Description

Method for manufacturing a bio-piezoelectric layer, a bio-piezoelectric layer manufactured using the same, a method for manufacturing a piezoelectric power generation element, and a piezoelectric power generation element manufactured using the same

[0001] The present invention relates to a method for manufacturing a bio-piezoelectric layer, a bio-piezoelectric layer manufactured using the same, a method for manufacturing a piezoelectric power generation device, and a piezoelectric power generation device manufactured using the same. More specifically, the present invention relates to a method for manufacturing a bio-piezoelectric layer capable of selectively growing only crystal structures with excellent piezoelectric properties by controlling the thermodynamic properties of glycine crystals, a bio-piezoelectric layer manufactured using the same, a method for manufacturing a piezoelectric power generation device, and a piezoelectric power generation device manufactured using the same.

[0002] Recently, the development of telecommunications technology has led to the emergence of various types of electronic devices. For instance, the demand for electronic devices such as portable devices is exploding as they enable user-centric ubiquitous computing. Portable devices may include portable power sources like batteries, but battery technology has limitations as it is disposable or requires periodic charging. Consequently, the need for energy harvesting in electronic devices is emerging.

[0003] Energy harvesting refers to a technology capable of converting wasted mechanical energy—such as vibrations from trains, vacuum pumps, mechanical motors, automobile engines, and human movements—into electrical energy.

[0004] Conventionally, poly-D-lactic acid and poly-L-lactic acid-based piezoelectric materials with a stereocomplex crystal structure exhibiting thermal stability and piezoelectric properties were realized through electrospinning and annealing processes.

[0005] However, biocompatible piezoelectric materials based on PLA have a problem in that high voltage and heat are required during the manufacturing process to enhance the piezoelectric performance of the material itself.

[0006] Embodiments of the present invention aim to provide a method for manufacturing a bio-piezoelectric layer capable of producing a high-efficiency bio-piezoelectric material using a simple and decisive process method of attracting a substrate, a bio-piezoelectric layer manufactured using the same, a method for manufacturing a piezoelectric power generation device, and a piezoelectric power generation device manufactured using the same.

[0007] The embodiments of the present invention aim to provide a method for manufacturing a bio-piezoelectric layer that can selectively and uniformly synthesize alpha and beta crystals of glycine by controlling process parameters, and in particular, secure uniform beta glycine crystals, a bio-piezoelectric layer manufactured using the same, a method for manufacturing a piezoelectric power generation device, and a piezoelectric power generation device manufactured using the same.

[0008] A method for manufacturing a bio-piezoelectric layer according to an embodiment of the present invention comprises the steps of: preparing a glycine solution by mixing glycine powder and a second solvent in a first solvent; immersing a substrate in the glycine solution; and pulling the substrate upward from the glycine solution to produce glycine crystals.

[0009] The step of manufacturing the glycine crystal above can control the crystal structure of the glycine crystal by controlling the pulling speed of the substrate.

[0010] The pulling speed of the above substrate may be 30 μm / min to 900 μm / min.

[0011] The above glycine crystal may have a beta structure.

[0012] The concentration of the above glycine solution may be 0.5M to 2M.

[0013] The above substrate may include at least one of aluminum (Al), gold (Au), chromium (Cr), silver (Ag), platinum (Pt) and copper (Cu).

[0014] The second solvent may include at least one of ethanol, methanol, and dimethyl ether (DME).

[0015] A bio-piezoelectric layer according to an embodiment of the present invention is manufactured according to a method for manufacturing a bio-piezoelectric layer according to an embodiment of the present invention and comprises a substrate; and a glycine crystal layer formed on the substrate and comprising glycine crystals.

[0016] The above glycine crystal may have a beta structure.

[0017] A method for manufacturing a piezoelectric power generation element according to an embodiment of the present invention comprises: a step of forming a lower electrode on a lower substrate; a step of forming a glycine crystal layer on the lower electrode; a step of forming a protective layer on the glycine crystal layer; and a step of forming an upper substrate coated with an upper electrode on the protective layer; wherein the step of forming the glycine crystal layer comprises: a step of preparing a glycine solution by mixing glycine powder and a second solvent in a first solvent; a step of immersing a substrate having a lower electrode formed thereon in the glycine solution; and a step of producing a glycine crystal by pulling the substrate having the lower electrode formed thereon upward from the glycine solution.

[0018] The above glycine crystal layer includes glycine crystals, and the glycine crystals may have a beta structure.

[0019] A piezoelectric power generation element according to an embodiment of the present invention is manufactured according to a method for manufacturing a piezoelectric power generation element according to an embodiment of the present invention and comprises: a lower electrode formed on a lower substrate; a glycine crystal layer formed on the lower electrode; a protective layer formed on the glycine crystal layer; an upper electrode formed on the protective layer; and an upper substrate formed on the upper electrode.

[0020] The above glycine crystal layer includes glycine crystals, and the glycine crystals may have a beta structure.

[0021] According to an embodiment of the present invention, a piezoelectric layer capable of manufacturing a high-efficiency bio-piezoelectric material using a simple and decisive process method of attracting a substrate, a method for manufacturing a piezoelectric power generation element, and a piezoelectric power generation element manufactured using the same can be provided.

[0022] According to an embodiment of the present invention, a piezoelectric layer capable of selectively and uniformly synthesizing alpha crystals and beta crystals of glycine by controlling process parameters, a method for manufacturing a piezoelectric power generation device, and a piezoelectric power generation device manufactured using the same can be provided.

[0023] FIG. 1 is a schematic diagram illustrating a method for manufacturing a bio-piezoelectric layer according to an embodiment of the present invention.

[0024] FIG. 2 is a schematic diagram illustrating the change in crystal structure according to the pulling speed in the method for manufacturing a bio-piezoelectric layer according to an embodiment of the present invention.

[0025] FIG. 3 is a schematic diagram illustrating a piezoelectric power generation element according to an embodiment of the present invention.

[0026] Figure 4 is an optical microscope (OM) image showing the shape of glycine crystals according to pulling speed and glycine concentration.

[0027] Figure 5 is a scanning electron microscope (SEM) image showing the shape of glycine crystals according to pulling speed and glycine concentration.

[0028] Figures 6 and 7 are graphs showing the results of X-ray diffraction (XRD) analysis of glycine crystals according to pulling speed and glycine concentration.

[0029] Figure 8 is a graph showing the phase diagram of glycine crystals according to pulling speed and glycine concentration.

[0030] Figure 9 is an image showing the piezoelectric microscopy (PFM) measurement results of beta-glycine crystals and alpha-glycine crystals.

[0031] Figure 10 is a graph showing the piezoelectric coefficients of beta-glycine crystals and alpha-glycine crystals.

[0032] Figures 11 and 12 are graphs showing the voltage and current characteristics of a beta-glycine piezoelectric element and an alpha-glycine piezoelectric element.

[0033] Figure 13 is a graph showing the output voltage and current density according to the resistance of a beta-glycine piezoelectric element.

[0034] Figure 14 is a graph showing the power density according to the resistance of a beta-glycine piezoelectric element.

[0035] Figure 15 is a graph showing the output stability of a beta-glycine piezoelectric element.

[0036] Embodiments of the present invention will be described in detail below with reference to the attached drawings and the contents described therein, but the present invention is not limited or restricted by the embodiments.

[0037] The terms used herein are for describing the embodiments and are not intended to limit the invention. In this specification, the singular form includes the plural form unless specifically stated otherwise in the text. As used herein, "comprises" and / or "comprising" do not exclude the presence or addition of one or more other components or steps mentioned in the description.

[0038] As used herein, terms such as “examples,” “examples,” “aspects,” “examples,” etc., are not to be interpreted as implying that any described aspect or design is superior or advantageous to other aspects or designs.

[0039] Furthermore, the term 'or' refers to an inclusive or rather an exclusive or. That is, unless otherwise noted or is clear from the context, the expression 'x uses a or b' refers to any one of the natural inclusive permutations.

[0040] Additionally, singular expressions (“a” or “an”) used in this specification and claims should generally be interpreted to mean “one or more” unless otherwise stated or it is clear from the context that they relate to the singular form.

[0041] The terms used in the following description have been selected as common and universal in the relevant technical field, but other terms may exist depending on technological development and / or changes, conventions, preferences of the skilled technician, etc. Therefore, the terms used in the following description should not be understood as limiting the technical concept, but as illustrative terms to explain the embodiments.

[0042] In addition, in specific cases, there are terms arbitrarily selected by the applicant, and in such cases, their detailed meanings will be described in the relevant explanatory section. Therefore, the terms used in the description below must be understood not merely as their names, but based on their meanings and the content throughout the specification.

[0043] Unless otherwise defined, all terms used in this specification (including technical and scientific terms) may be used in a meaning that is commonly understood by those skilled in the art to which the present invention pertains. Additionally, terms defined in commonly used dictionaries are not to be interpreted ideally or excessively unless explicitly and specifically defined otherwise.

[0044] Meanwhile, in describing the present invention, if it is determined that a detailed description of related known functions or configurations could unnecessarily obscure the essence of the invention, such detailed description will be omitted. Furthermore, the terminology used in this specification is used to appropriately express embodiments of the present invention, and such terminology may vary depending on the intent of the user or operator, or the conventions of the field to which the invention belongs. Accordingly, the definitions of these terms should be based on the content throughout this specification.

[0045]

[0046] FIG. 1 is a schematic diagram illustrating a method for manufacturing a bio-piezoelectric layer according to an embodiment of the present invention, and FIG. 2 is a schematic diagram illustrating a change in crystal structure according to the pulling speed in a method for manufacturing a bio-piezoelectric layer according to an embodiment of the present invention.

[0047] A method for manufacturing a bio-piezoelectric layer according to an embodiment of the present invention comprises the steps of: preparing a glycine solution by mixing glycine powder (120) and a second solvent (112) in a first solvent (111) (S110); immersing a substrate (130) in the glycine solution (S120); and pulling the substrate (130) upward from the glycine solution to produce a glycine crystal (140) (S130).

[0048] Accordingly, the method for manufacturing a bio-piezoelectric layer according to an embodiment of the present invention can manufacture a high-efficiency bio-piezoelectric material by using a simple and decisive process method of pulling a substrate (130).

[0049] First, the method for manufacturing a bio-piezoelectric layer according to an embodiment of the present invention proceeds with the step (S110) of preparing a glycine solution by mixing glycine powder (120) and a second solvent (112) in a first solvent (111).

[0050] Glycine is the simplest amino acid with a non-chiral structure that can be used as a natural piezoelectric biomaterial. Beta-glycine, which corresponds to the central asymmetric space group P21 among glycine polymorphs (alpha, beta, gamma), possesses high shear piezoelectric properties comparable to those of the existing piezoelectric ceramic material BaTiO3; therefore, using beta-glycine as a piezoelectric material can secure biocompatible, high-efficiency energy conversion technology that complements the low piezoelectric properties of existing natural piezoelectric materials.

[0051] Accordingly, the method for manufacturing a bio-piezoelectric layer according to an embodiment of the present invention enables the securing of uniform beta-glycine crystals and the control of crystal size by controlling the thermodynamic instability of beta-glycine through the adjustment of process parameters such as the ratio of the glycine solution, immersion, and substrate pulling.

[0052] The size of the glycine powder can be tens of nanometers to tens of micrometers.

[0053] The first solvent (111) is a solvent capable of dissolving glycine powder, and the second solvent (112) may be a solvent that promotes crystal formation by breaking the hydrogen bond between the amphoteric ions of glycine and the first solvent (111).

[0054] Accordingly, the method for manufacturing a bio-piezoelectric layer according to an embodiment of the present invention can control the crystal precipitation rate according to the weight ratio of the first solvent (111) and the second solvent (112), and can control whether crystals are formed and the type of glycine crystal phase according to the crystal precipitation rate.

[0055] For example, the weight ratio of the first solvent (111) and the second solvent (112) may be 5:1 to 1:0, and if the weight ratio of the first solvent (111) and the second solvent (112) exceeds 5:1, the solubility of the solution is lowered, and undissolved glycine crystals in the solution may hinder the growth of crystals formed on the substrate. Additionally, as the ratio of the second solvent (112) approaches 0, the volatility of the solution decreases, and alpha-glycine may be formed instead of beta-glycine.

[0056] The first solvent (111) may contain water.

[0057] The second solvent (112) may include at least one of ethanol, methanol, and dimethyl ether (DME).

[0058] In particular, glycine can be precipitated from a solution with low biotoxicity, including ethanol as the second solvent (112).

[0059] Therefore, the method for manufacturing a bio-piezoelectric layer according to an embodiment of the present invention is a simple, economical, and environmentally friendly process by using water and ethanol as solvents.

[0060] The method for manufacturing a bio-piezoelectric layer according to an embodiment of the present invention can control the volatilization rate of the solution by controlling the temperature of the glycine solution. Accordingly, the method for manufacturing a bio-piezoelectric layer according to an embodiment of the present invention can form beta-glycine crystals at an appropriate volatilization rate of the solution.

[0061] The temperature of the glycine solution can be 30°C to 35°C. If the temperature of the glycine solution is below 30°C, there is a problem that beta-glycine does not precipitate, and if it exceeds 35°C, there is a problem that the crystal size and amount of beta-glycine decrease.

[0062] The method for manufacturing a bio-piezoelectric layer according to an embodiment of the present invention can control the precipitation rate of the solution by controlling the process humidity.

[0063] The process humidity can be 10% to 30%, and if the humidity of the glycine solution exceeds 30%, there is a problem that glycine crystals are not formed uniformly and only alpha-glycine is produced instead of beta-glycine, and if the process humidity is less than 10%, it is difficult to create an environment where the air flow rate can be ignored, so glycine precipitation does not occur properly.

[0064] According to the example, the temperature and process humidity of the glyphine solution can be maintained the same from S110 to S130.

[0065] Afterwards, the method for manufacturing a bio-piezoelectric layer according to an embodiment of the present invention proceeds with the step (S120) of immersing a substrate (130) in a glycine solution.

[0066] The step (S120) of immersing the substrate (130) in a glycine solution allows nuclei to be formed on the substrate (130) as the substrate (130) is immersed in the glycine solution.

[0067] The method for manufacturing a bio-piezoelectric layer according to an embodiment of the present invention can control the crystal structure of glycine crystals by controlling the concentration of the glycine solution.

[0068] Specifically, as the concentration of the glycine solution increases, the density and size of the glycine crystals may increase, and as the concentration of the glycine solution decreases, the density and size of the crystals may decrease.

[0069] Accordingly, the method for manufacturing a bio-piezoelectric layer according to an embodiment of the present invention can produce glycine crystals having a desired crystal structure by controlling the concentration of the glycine solution.

[0070] The concentration of the glycine solution can be 0.5M to 2M. If the concentration of the glycine solution is less than 0.5M, there is a problem that the glycine concentration in the solution is insufficient and crystals do not precipitate on the substrate, and if it exceeds 2M, the glycine concentration in the solution exceeds the saturation level, and the undissolved glycine interferes with crystal precipitation on the substrate.

[0071] The step (S120) of immersing the substrate (130) in a glycine solution allows for the nucleation of glycine crystals (140) and the uniformity of glycine crystals (140) on the substrate (130) to be controlled according to the immersion time of the substrate (130).

[0072] Specifically, if the immersion time of the substrate (130) is prolonged, alpha glycine may be formed, and if the immersion time of the substrate (130) is shortened, nucleation of glycine may not occur sufficiently, so glycine crystals (140) may not be formed or non-uniform glycine crystals (140) may be formed.

[0073] For example, the immersion time of the substrate (130) may be 2 to 3 hours, and if the immersion time of the substrate (130) is less than 2 hours, beta-glycine or alpha-glycine may be formed unevenly, and if it exceeds 3 hours, the glycine process time may be prolonged and alpha-glycine may be synthesized.

[0074] The substrate (130) may include at least one of an organic substrate and an inorganic substrate.

[0075] The inorganic substrate may include at least one of metal, glass, quartz, Al2O3, Si, and SiO2.

[0076] The metal may include at least one of aluminum (Al), gold (Au), chromium (Cr), silver (Ag), platinum (Pt), and copper (Cu).

[0077] The organic substrate may include at least one of Kapton foil, polyimide (PI), polyethersulfone (PES), polyacrylate (PAR), polyetherimide (PEI), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polyarylate, polycarbonate (PC), cellulose triacetate (CTA), and cellulose acetate propionate (CAP).

[0078] Preferably, the substrate (130) may include a metal, and more preferably, the substrate (130) may include aluminum.

[0079] According to the embodiment, the substrate (130) serves to support glycine crystals and, when applied to a piezoelectric power generation element, can be used as a lower substrate / lower electrode or lower electrode.

[0080] For example, when the substrate (130) serves as a lower substrate / lower electrode, the substrate (130) may include a stacked structure of an organic substrate / inorganic substrate or an inorganic / substrate / inorganic substrate.

[0081] For example, if a metal such as aluminum is used as the substrate (130), the metal such as aluminum can subsequently be used as the lower electrode of the piezoelectric element, so that a piezoelectric power generation element can be manufactured without an additional adhesion process between the glycine crystal (140) and the lower electrode.

[0082] Finally, the step (S130) of pulling the substrate (130) upward from the glycine solution to produce a glycine crystal (140) is carried out.

[0083] In the step (S130) of manufacturing the glycine crystal (140), the substrate (130) on which the nucleus was generated in S130 is pulled out of the glycine solution, and at the same time, the second solvent volatilizes, allowing the glycine crystal (140) to grow.

[0084] The step (S130) of manufacturing the glycine crystal (140) can control the uniformity of the glycine crystal (140) by adjusting the pulling angle of the substrate (130).

[0085] The pulling angle of the substrate (130) may be +15 degrees to -15 degrees, and if the pulling angle of the substrate (130) exceeds ±15 degrees, there is a problem that the glycine crystals (140) on the substrate (130) are not formed uniformly.

[0086] The step (S130) of manufacturing the glycine crystal (140) can control the crystal structure of the glycine crystal (140) by controlling the pulling speed of the substrate (130).

[0087] Specifically, when the pulling speed of the substrate (130) increases, the glycine crystal (140) can grow rapidly on the substrate (130) to form a beta-glycine structure, and when the pulling speed of the substrate (140) decreases, an alpha-glycine structure can be formed. Additionally, as the pulling speed of the substrate (130) increases, the aspect ratio of the crystal structure of the generated beta-glycine can increase.

[0088] Accordingly, the method for manufacturing a bio-piezoelectric layer according to an embodiment of the present invention can produce glycine crystals having a desired crystal structure by controlling the pulling speed of the substrate (130).

[0089] The pulling speed of the substrate (130) may be 30 μm / min to 900 μm / min. If the pulling speed of the substrate (130) is less than 30 μm / min, there is a problem that the time to obtain sufficient glycine crystals becomes long. If it exceeds 900 μm / min, there is no significant change in the volatilization rate of the solution due to the low volatility of water, and there may be no change in the crystal structure formed. However, when the pulling speed is very fast, the glycine crystals may not be formed uniformly due to reasons such as the cohesive force of water.

[0090] For example, the crystal structure of glycine is a polymorph that can have alpha, beta, and gamma structures, and the method for manufacturing a bio-piezoelectric layer according to an embodiment of the present invention can selectively and uniformly synthesize alpha and beta crystals of glycine by controlling process parameters, and in particular, can secure uniform beta glycine crystals over a large area.

[0091] Thermodynamically unstable beta-glycine can be formed before other crystal structures and then changed into stable alpha-glycine.

[0092] Specifically, the method for manufacturing a bio-piezoelectric layer according to an embodiment of the present invention can stably manufacture an unstable beta structure by controlling at least one of the volatilization rate of the substrate material and the glycine solution.

[0093] For example, if the pulling speed of the substrate (130) increases, the volatilization rate of the glycine solution increases, and the growth of the glycine crystal occurs rapidly, so a glycine crystal with a beta structure can be produced, and if the pulling speed of the substrate (130) decreases, the volatilization rate of the glycine solution decreases, and the beta glycine structure formed first is converted into alpha glycine, so an alpha glycine crystal can be produced.

[0094] Glycine crystals may have an alpha structure or a beta structure, and preferably, glycine crystals may have a beta structure.

[0095] Beta-glycine is a material that is highly sensitive to the type of substrate (130), the time required for nucleation, temperature, humidity, and the evaporation rate of the solvent because it has poor thermodynamic stability. However, the method for manufacturing a bio-piezoelectric layer according to an embodiment of the present invention can selectively and uniformly synthesize alpha crystals and beta crystals of glycine, and in particular, by controlling the thermodynamic properties of the glycine crystals, it is possible to selectively grow only beta-glycine crystals with excellent piezoelectric properties, and based on the manufactured beta-glycine crystals, a piezoelectric power generation device with excellent biocompatibility and high piezoelectric performance can be realized.

[0096] In addition, the method for manufacturing a bio-piezoelectric layer according to an embodiment of the present invention can be usefully utilized in the pharmaceutical, food, medical, and chemical industries by using process technology for controlling the polymorphic crystal structure of glycine.

[0097] A bio-piezoelectric layer according to an embodiment of the present invention can be manufactured using a method for manufacturing a bio-piezoelectric layer according to an embodiment of the present invention.

[0098] The bio-piezoelectric layer according to an embodiment of the present invention comprises a substrate (130) and a glycine crystal layer formed on the substrate (130) and including a glycine crystal (140).

[0099] Glycine crystals may have an alpha structure or a beta structure, and preferably, glycine crystals may have a beta structure.

[0100] The shape of the glycine crystal layer can be a nanofiber or a membrane.

[0101] In the case of the beta-glycine structure, the aspect ratio of the crystal is large and it is not formed with a high density enough to cover the entire substrate (130), so it can have a shape like a nanofiber, and in the case of alpha-glycine, it is formed with a high density and thickness enough to cover the entire substrate (130), so it can have a shape like a film.

[0102] Glycine is the simplest unit of amino acids and can be utilized as a piezoelectric material to achieve excellent biocompatibility and improved piezoelectric performance compared to existing bio-derived bio-piezoelectric devices.

[0103] Accordingly, the bio-piezoelectric layer according to the embodiment of the present invention can be utilized in various fields as well as in the biomedical field, such as as a bio-implantable material and device, a self-driving sensor, and an energy source.

[0104] Hereinafter, with reference to FIG. 3, a method for manufacturing a piezoelectric power generation element according to an embodiment of the present invention and a piezoelectric power generation element according to an embodiment of the present invention will be described.

[0105]

[0106] FIG. 3 is a schematic diagram illustrating a piezoelectric power generation element according to an embodiment of the present invention.

[0107] Since the method for manufacturing a piezoelectric power generation element according to an embodiment of the present invention includes the same components as the method for manufacturing a bio-piezoelectric layer according to an embodiment of the present invention, the description of the same components will be omitted.

[0108] A method for manufacturing a piezoelectric power generation element according to an embodiment of the present invention comprises the steps of forming a lower electrode (220) on a lower substrate (210) (S210), forming a glycine crystal layer (230) on the lower electrode (210) (S220), forming a protective layer (240) on the glycine crystal layer (230) (S230), and forming an upper substrate (260) coated with an upper electrode (250) on the protective layer (240) (S240).

[0109] A method for manufacturing a piezoelectric power generation element according to an embodiment of the present invention proceeds with the step (S210) of forming a lower electrode (220) on a substrate (210).

[0110] The lower substrate (210) may include at least one of an organic substrate and an inorganic substrate.

[0111] The inorganic substrate may include at least one of glass, quartz, Al2O3, Si, and SiO2.

[0112] The organic material substrate may include at least one of Kapton foil, polyimide (PI), polyethersulfone (PES), polyacrylate (PAR), polyetherimide (PEI), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polyarylate, polycarbonate (PC), cellulose triacetate (CTA), and cellulose acetate propionate (CAP).

[0113] The lower electrode (210) may include at least one of aluminum (Al), gold (Au), chromium (Cr), silver (Ag), platinum (Pt) and copper (Cu).

[0114] The lower electrode (220) can be formed on the lower substrate (210) by any one of the following methods: thermal evaporation, electron beam evaporation, radio frequency sputtering, magnetron sputtering, vacuum deposition, or chemical vapor deposition.

[0115] Afterwards, the method for manufacturing a piezoelectric power generation element according to an embodiment of the present invention proceeds to the step (S220) of forming a piezoelectric layer (230) on a lower electrode (210).

[0116] The step (S220) of forming a glycine crystal layer (230) includes the step (S221) of preparing a glycine solution by mixing glycine powder and a second solvent in a first solvent, the step (S222) of immersing a substrate (210) having a lower electrode (220) formed thereon in the glycine solution, and the step (S223) of preparing a glycine crystal by pulling the substrate (210) having the lower electrode (220) formed thereon up from the glycine solution.

[0117] The glycine crystal layer (230) may include the same components as the bio-piezoelectric layer according to an embodiment of the present invention.

[0118] The glycine crystal layer (230) may include glycine crystals, and the glycine crystals may have an alpha structure or a beta structure, and preferably, the glycine crystals may have a beta structure.

[0119] Afterwards, the method for manufacturing a piezoelectric power generation element according to an embodiment of the present invention proceeds to the step (S230) of forming a protective layer (240) on a glycine crystal layer (230).

[0120] The protective layer (240) protects the glycine crystals and forms an insulating film, thereby preventing a short circuit that may occur from the upper and lower electrodes.

[0121] The protective layer (240) can be formed by any one of the following methods: spin coating, spray coating, ultra-spray coating, electrospinning coating, slot die coating, gravure coating, bar coating, roll coating, dip coating, shear coating, screen printing, inkjet printing, or nozzle printing.

[0122] The protective layer (240) may include at least one of polylactic acid (PLA), polymethyl methacrylate (PMMA), polycaprolactone (PCL), and PHBV (Poly(3-hydroxybutyrate-co-3-hydroxyvalerate)).

[0123] Finally, the method for manufacturing a piezoelectric power generation element according to an embodiment of the present invention proceeds with the step (S240) of forming an upper substrate (260) coated with an upper electrode (250) on a protective layer (240).

[0124] The upper substrate (260) may include at least one of an organic substrate and an inorganic substrate.

[0125] The inorganic substrate may include at least one of glass, quartz, Al2O3, Si, and SiO2.

[0126] The organic material substrate may include at least one of Kapton foil, polyimide (PI), polyethersulfone (PES), polyacrylate (PAR), polyetherimide (PEI), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polyarylate, polycarbonate (PC), cellulose triacetate (CTA), and cellulose acetate propionate (CAP).

[0127] The upper electrode (250) may include at least one of aluminum (Al), gold (Au), chromium (Cr), silver (Ag), platinum (Pt) and copper (Cu).

[0128] The upper electrode (250) can be formed on the upper substrate (260) by any one of the following methods: tape adhesion, thermal evaporation, electron beam evaporation, radio frequency sputtering, magnetron sputtering, vacuum deposition, or chemical vapor deposition.

[0129] For example, the method for manufacturing a piezoelectric power generation element according to an embodiment of the present invention can be fixed by attaching tape to the outer surface of the upper and lower electrodes.

[0130] Accordingly, a piezoelectric power generation element according to an embodiment of the present invention can be manufactured according to the method for manufacturing a piezoelectric power generation element according to an embodiment of the present invention.

[0131] A piezoelectric power generation element according to an embodiment of the present invention includes a lower electrode (220) formed on a lower substrate (210), a glycine crystal layer (230) formed on the lower electrode (220), a protective layer (240) formed on the glycine crystal layer (230), an upper electrode (250) formed on the protective layer (240), and an upper substrate (260) formed on the upper electrode (250).

[0132] The glycine crystal layer (230) may include the same components as the bio-piezoelectric layer according to an embodiment of the present invention.

[0133] The glycine crystal layer (230) may include glycine crystals, and the glycine crystals may have an alpha structure or a beta structure, and preferably, the glycine crystals may have a beta structure.

[0134] The piezoelectric power generation device according to an embodiment of the present invention uses beta-glycine crystals with excellent piezoelectric performance as a piezoelectric material, so it can be utilized as an energy source, sensor, new material for bio-implantation, therapeutic agent, etc. in various fields including the medical field.

[0135]

[0136] Experimental Example 1: Shape of glycine crystals according to substrate pulling speed and glycine solution concentration

[0137] Example 1

[0138] Add glycine powder to water to achieve glycine solution concentrations of 0.5M, 1M, 1.5M, and 2M, and mix using a vortex cleaner and an ultrasonic cleaner. Add ethanol to achieve a water-to-ethanol ratio of 13:1 and mix thoroughly in the same manner as above. Transfer the solution into a 2 mL tube. Cut the aluminum-coated substrate, an Al / Si wafer or Al / PEN, into a size of 0.5 cm x 2.5 cm. Secure the substrate to a syringe pump and immerse it in the solution contained in the 2 mL tube. Set the syringe pump program to maintain a pulling speed of 3.0 nm / min for 3 hours, and then set the pulling speed to 30 / 50 / 100 / 300 / 500 / 700 / 900 µm / min after 3 hours. Use a humidity desiccator, a hot plate, and a heater to maintain the humidity inside the desiccator at 15–30% and the temperature at 30–35 ℃. Once the substrate is completely separated from the solution, collect and store the sample.

[0139]

[0140] Figure 4 is an optical microscope (OM) image showing the shape of glycine crystals according to pulling speed and glycine concentration, and Figure 5 is a scanning electron microscope (SEM) image showing the shape of glycine crystals according to pulling speed and glycine concentration.

[0141] Referring to Figures 4 and 5, it can be seen that as the pulling speed of the substrate increases and the concentration of glycine decreases, the aspect ratio increases and the ratio of the area of ​​the glycine crystal to the area of ​​the substrate decreases.

[0142]

[0143] Figures 6 and 7 are graphs showing the results of X-ray diffraction (XRD) analysis of glycine crystals according to pulling speed and glycine concentration.

[0144] Referring to FIGS. 6 to 8, it can be seen that when the pulling speed of the substrate is 50 μm / min or less, glycine crystals with an alpha structure are formed, and as the speed increases, glycine crystals with a distinct beta structure are formed.

[0145] In particular, when the glycine concentration is 2M, it can be seen that only beta crystals are formed when the substrate pulling speed is 500 μm / min or higher.

[0146]

[0147] Experimental Example 2: Changes in Properties of Beta-Glycine and Alpha-Glycine

[0148] Comparative Example 1: Quartz

[0149] Quartz manufactured by MTIKorea was used (Product names: X Cut single crystal quartz, Y Cut single crystal quartz)

[0150]

[0151] Example 2-1: β Glycine

[0152] It was prepared in the same manner as in Example 1 by applying a pulling speed of 500 μm / min and a 2M glycine solution.

[0153]

[0154]

[0155] Example 2-2: α Glycine

[0156] It was prepared in the same manner as in Example 1 by applying a pulling speed of 30 μm / min and a 1M glycine solution.

[0157]

[0158] Figure 9 is an image showing the piezoelectric force microscopy (PFM) measurement results of beta-glycine crystals and alpha-glycine crystals, and Figure 10 is a graph showing the piezoelectric coefficients of beta-glycine crystals and alpha-glycine crystals.

[0159] Referring to Figures 9 and 10, when an electric field was applied perpendicular to beta-glycine and the piezoelectric properties were measured in the perpendicular direction or in a direction parallel to the substrate, the piezoelectric coefficient was found to be 90 pm / V or higher.

[0160]

[0161] Experimental Example 3: Changes in Characteristics of Glycine Piezoelectric Irradiation

[0162] Example 3-1: β Glycine

[0163] It was prepared in the same manner as in Example 1 by applying a 2M glycine solution at a pulling speed of 700 μm / min to an Al / PEN substrate.

[0164]

[0165] Example 3-2: α Glycine

[0166] It was prepared in the same manner as in Example 1 by applying a 2M glycine solution at a pulling speed of 50 μm / min to an Al / PEN substrate.

[0167]

[0168] Figures 11 and 12 are graphs showing the voltage and current characteristics of a beta-glycine piezoelectric element and an alpha-glycine piezoelectric element.

[0169] Referring to Figures 11 and 12, it can be seen that when 20 N is applied to the beta-glycine piezoelectric element, the output voltage and current are 4 V and 0.5 μA, respectively.

[0170]

[0171] Figure 13 is a graph showing the output voltage and current density according to the resistance of a beta-glycine piezoelectric element, and Figure 14 is a graph showing the power density according to the resistance of a beta-glycine piezoelectric element.

[0172] Referring to FIGS. 13 and 14, the maximum power density is 20 μVA / cm² at a resistance of 10 megaohms. 2 It can be seen that it is.

[0173]

[0174] Figure 15 is a graph showing the output stability of a beta-glycine piezoelectric element.

[0175] Referring to Fig. 15, it can be seen that the output remains stable even when pressure is applied 10,000 times.

[0176]

[0177] As described above, although the present invention has been explained by limited embodiments and drawings, the present invention is not limited to the above embodiments, and various modifications and variations are possible from this description by those skilled in the art to which the present invention belongs. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined by the claims set forth below as well as equivalents thereof.

Claims

1. A step of preparing a glycine solution by mixing glycine powder and a second solvent in a first solvent; A step of immersing a substrate in the above glycine solution; and A step of preparing glycine crystals by pulling the substrate upward from the glycine solution; A method for manufacturing a bio-piezoelectric layer characterized by including 2. In Paragraph 1, The step of manufacturing the above glycine crystals is, A method for manufacturing a bio-piezoelectric layer characterized by controlling the crystal structure of the glycine crystal by adjusting the pulling speed of the substrate.

3. In Paragraph 2, A method for manufacturing a bio-piezoelectric layer characterized by the pulling speed of the substrate being 30 μm / min to 900 μm / min.

4. In Paragraph 2, A method for manufacturing a bio-piezoelectric layer characterized in that the above-mentioned glycine crystal has a beta structure.

5. In Paragraph 1, A method for manufacturing a bio-piezoelectric layer characterized by the concentration of the glycine solution being 0.5M to 2M.

6. In Paragraph 1, A method for manufacturing a bio-piezoelectric layer, characterized in that the substrate comprises at least one of aluminum (Al), gold (Au), chromium (Cr), silver (Ag), platinum (Pt), and copper (Cu).

7. In Paragraph 1, A method for manufacturing a bio-piezoelectric layer characterized in that the first solvent comprises water.

8. In Paragraph 1, A method for manufacturing a bio-piezoelectric layer, characterized in that the second solvent comprises at least one of ethanol, methanol, and dimethyl ether (DME).

9. Manufactured according to the method for manufacturing a bio-piezoelectric layer pursuant to Paragraph 1, and Substrate; and A glycine crystal layer formed on the above substrate and comprising glycine crystals; A bio-piezoelectric layer characterized by including 10. In Paragraph 9, A bio-piezoelectric layer characterized by the above-mentioned glycine crystal having a beta structure.

11. A step of forming a lower electrode on a lower substrate; A step of forming a glycine crystal layer on the lower electrode; A step of forming a protective layer on the glycine crystal layer; and A step of forming an upper substrate coated with an upper electrode on the above protective layer; Includes, The step of forming the above glycine crystal layer is, A step of preparing a glycine solution by mixing glycine powder and a second solvent in a first solvent; A step of immersing a substrate having a lower electrode formed thereon in the above glycine solution; and A step of producing glycine crystals by pulling the substrate having the lower electrode formed thereon upward from the glycine solution; A method for manufacturing a piezoelectric power generation element characterized by including 12. In Paragraph 11, A method for manufacturing a piezoelectric power generation element characterized in that the glycine crystal layer comprises glycine crystals, and the glycine crystals have a beta structure.

13. Manufactured according to the method for manufacturing a piezoelectric power generation element pursuant to Paragraph 11, and A lower electrode formed on a lower substrate; A glycine crystal layer formed on the lower electrode above; A protective layer formed on the above glycine crystal layer; An upper electrode formed on the above protective layer; and An upper substrate formed on the upper electrode; A piezoelectric power generation element characterized by including 14. In Paragraph 13, A piezoelectric power generation element characterized in that the glycine crystal layer comprises glycine crystals, and the glycine crystals have a beta structure.

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