0-3 type piezoelectric thin film, method for preparing the same, and use thereof

Abstract

The application relates to a 0-3 type piezoelectric film and a preparation method and application thereof, the 0-3 type piezoelectric film at least comprising a 0-3 type piezoelectric material layer, the 0-3 type piezoelectric material layer comprising lead indium niobate-lead niobium magnesiumate-lead titanate nanoparticles and polyvinylidene fluoride-trifluoroethylene at a volume ratio of 3:7-8:2; in the lead indium niobate-lead niobium magnesiumate-lead titanate nanoparticles, the proportion of lead indium niobate is 24wt.%-28wt.%, the proportion of lead niobium magnesiumate is 42wt.%-48wt.%, and the proportion of lead titanate is 26wt.%-32wt.%. The prepared 0-3 type piezoelectric film can simultaneously have high piezoelectricity and good mechanical flexibility under high-temperature working conditions, thereby meeting the application requirements of a new generation of electronic devices such as high-frequency flexible ultrasonic transducers and high-sensitivity tactile sensors in the stable working of high-temperature fields.

Description

Technical Field

[0001] This invention relates to the field of piezoelectric materials technology, and in particular to 0-3 type piezoelectric thin films, their preparation methods, and applications. Background Technology

[0002] With the rapid development of cutting-edge technologies such as embody intelligence, virtual reality / augmented reality, and electronic skin, higher requirements are placed on piezoelectric devices, the core sensing and driving components, creating an urgent need for piezoelectric materials that combine high energy conversion efficiency, excellent mechanical flexibility, and good environmental stability.

[0003] However, traditional single-component piezoelectric materials all have inherent limitations that are difficult to overcome. For example, although piezoelectric ceramics, represented by lead zirconate titanate (PZT), have a high piezoelectric strain constant, their intrinsic brittleness and high Young's modulus make them unsuitable for applications in bending, stretching, or conformal bonding scenarios. On the other hand, piezoelectric polymers such as polyvinylidene fluoride-trifluoroethylene (P(VDF-TrFE)) have good flexibility and processability, but their low piezoelectric constants result in serious deficiencies in energy conversion efficiency and signal sensitivity in devices fabricated based on them. Although traditional PZT / P(VDF-TrFE) composite films attempt to integrate the advantages of both, their piezoelectric properties and flexibility significantly degrade under high-temperature operating conditions, making it difficult to meet the high requirements of next-generation high-frequency, high-precision ultrasonic transducers or micro-force sensors for weak signal transmission and reception. This greatly limits their application in high-temperature, high-end flexible electronics. Summary of the Invention

[0004] Based on this, it is necessary to provide a 0-3 type piezoelectric thin film, its preparation method, and its application to address the above problems. The 0-3 type piezoelectric thin film can simultaneously possess high piezoelectricity and good mechanical flexibility under high-temperature working conditions, thereby meeting the application requirements of next-generation electronic devices such as high-frequency flexible ultrasonic transducers and high-sensitivity tactile sensors for stable operation in high-temperature fields.

[0005] A type 0-3 piezoelectric thin film, wherein the type 0-3 piezoelectric thin film comprises at least a type 0-3 piezoelectric material layer, wherein the type 0-3 piezoelectric material layer comprises lead indium niobate-lead magnesium niobate-lead titanate nanoparticles and polyvinylidene fluoride-trifluoroethylene in a volume ratio of 3:7 to 8:2;

[0006] In the aforementioned lead indium niobate-lead magnesium niobate-lead titanate nanoparticles, lead indium niobate accounts for 24 wt.%~28 wt.%, lead magnesium niobate accounts for 42 wt.%~48 wt.%, and lead titanate accounts for 26 wt.%~32 wt.%.

[0007] In one embodiment, the 0-3 type piezoelectric thin film further includes a first metal layer, a flexible substrate, and a second metal layer sequentially stacked on the 0-3 type piezoelectric material layer, wherein the first metal layer and the second metal layer are electrically connected.

[0008] In one embodiment, the average particle size of the lead indium niobate-lead magnesium niobate-lead titanate nanoparticles is 200 nm to 800 nm;

[0009] And / or, the thickness of the 0-3 type piezoelectric material layer is 10μm~100μm;

[0010] And / or, the thicknesses of the first metal layer and the second metal layer are each independently selected from 50 nm to 200 nm;

[0011] And / or, the thickness of the flexible substrate is 20μm~200μm;

[0012] And / or, the first metal layer and the second metal layer are each independently selected from at least one of a gold layer, an aluminum layer, or a platinum layer;

[0013] And / or, the flexible substrate is selected from at least one of polyimide substrate, polyetheretherketone substrate or polyetherimide substrate.

[0014] In one embodiment, the difference between the maximum and minimum particle size of the lead indium niobate-lead magnesium niobate-lead titanate nanoparticles is 100 nm to 300 nm.

[0015] In one embodiment, the lead indium niobate-lead magnesium niobate-lead titanate nanoparticles are modified with a coupling agent, and the mass ratio of the lead indium niobate-lead magnesium niobate-lead titanate nanoparticles to the coupling agent is 100:1~2.

[0016] In one embodiment, the coupling agent is selected from at least one of polyvinylpyrrolidone, dopamine, organic acid, aminosilane, or epoxysilane.

[0017] A method for preparing a 0-3 type piezoelectric thin film as described above includes the following steps:

[0018] A first metal layer and a second metal layer are deposited on the upper and lower surfaces of a flexible substrate, respectively, and the first metal layer and the second metal layer are electrically connected.

[0019] The first metal layer is subjected to surface activation treatment;

[0020] A type 0-3 piezoelectric material layer is prepared on the activated first metal layer;

[0021] Hot pressing is performed, followed by simultaneous polarization and annealing.

[0022] In one embodiment, the preparation method further satisfies at least one of the following conditions:

[0023] (1) The surface activation treatment is plasma treatment, which is carried out in a reaction chamber. The process parameters are: vacuum degree of 10Pa~100Pa, power of 50W~500W, and air is introduced into the reaction chamber for activation for 5min~10min.

[0024] (2) A type 0-3 piezoelectric material layer is prepared on the activated first metal layer using a type 0-3 piezoelectric material sol, wherein the coating amount of the type 0-3 piezoelectric material sol is 0.25 mL / cm. 2 ~0.40mL / cm 2 The 0-3 type piezoelectric material sol includes lead indium niobate-lead magnesium niobate-lead titanate nanoparticles, polyvinylidene fluoride-trifluoroethylene and solvent;

[0025] (3) The process parameters of the hot pressing treatment include: heating to 140℃~160℃ at a rate of 5℃ / min~10℃ / min, then applying a pressure of 20MPa~60MPa and holding the pressure and temperature for 30min~60min;

[0026] (4) The polarization and annealing treatment is carried out by gate-controlled corona polarization, applying an electric field of 1.0MV / m to 2.0MV / m at a temperature of 140℃ to 160℃ for 90min to 120min.

[0027] In one embodiment, the lead indium niobate-lead magnesium niobate-lead titanate nanoparticles are modified with a coupling agent, and the preparation steps include:

[0028] S1, lead indium niobate-lead magnesium niobate-lead titanate nanoparticles are activated in H2O2 solution;

[0029] S2, the activated lead indium niobate-lead magnesium niobate-lead titanate nanoparticles, coupling agent and solvent are mixed and stirred;

[0030] Repeat steps S1 and S2 3 to 7 times, and then dry and grind the final product.

[0031] An application of a type 0-3 piezoelectric thin film as described above in piezoelectric devices.

[0032] This invention uniformly disperses the inorganic phase of lead indium niobate-lead magnesium niobate-lead titanate nanoparticles in a 0-dimensional form within a three-dimensionally connected polyvinylidene fluoride-trifluoroethylene organic phase, successfully constructing a highly efficient stress transfer and charge transport network. This structural optimization exhibits significant performance improvements: by optimizing the two-phase ratio, the piezoelectric strain constant of the 0-3 type piezoelectric film is more than twice that of a single polyvinylidene fluoride-trifluoroethylene film, further endowing the 0-3 type piezoelectric film with mechanical flexibility and conformal adhesion to curved surfaces far superior to piezoelectric ceramics. Simultaneously, by optimizing the composition of the lead indium niobate-lead magnesium niobate-lead titanate nanoparticles, they possess a high Curie temperature and a high piezoelectric voltage constant. Ultimately, the piezoelectric film prepared by this invention integrates high piezoelectricity, high flexibility, and high-temperature stability, meeting the application requirements of high-frequency flexible ultrasonic transducers and high-sensitivity tactile sensors in high-temperature fields and complex scenarios. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a physical image of the 0-3 type piezoelectric thin film obtained in Embodiment 1 of the present invention;

[0035] Figure 2 This is an electron microscope image of the 0-3 type piezoelectric thin film obtained in Embodiment 1 of the present invention. Detailed Implementation

[0036] To facilitate understanding of the present invention, it will be described in more detail below. However, it should be understood that the present invention can be implemented in many different forms and is not limited to the embodiments or examples described herein. Rather, these embodiments or examples are provided to make the disclosure of the present invention more thorough and complete.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments or examples only and is not intended to limit the invention.

[0038] To address the shortcomings of traditional piezoelectric films, such as difficulty in simultaneously achieving high piezoelectricity and high flexibility, and unstable performance under high-temperature environments, this invention provides a 0-3 type piezoelectric film. The 0-3 type piezoelectric film includes at least a 0-3 type piezoelectric material layer, which comprises lead indium niobate-lead magnesium niobate-lead titanate nanoparticles and polyvinylidene fluoride-trifluoroethylene in a volume ratio of 3:7 to 8:2.

[0039] In the aforementioned lead indium niobate-lead magnesium niobate-lead titanate nanoparticles, lead indium niobate accounts for 24 wt.%~28 wt.%, lead magnesium niobate accounts for 42 wt.%~48 wt.%, and lead titanate accounts for 26 wt.%~32 wt.%.

[0040] This invention successfully constructs an efficient stress transfer and charge transport network by uniformly dispersing inorganic phases of lead indium niobate-lead magnesium niobate-lead titanate nanoparticles in a 0-dimensional form within a three-dimensionally connected organic phase of polyvinylidene fluoride-trifluoroethylene.

[0041] By optimizing the two-phase ratio, for example, selecting any value or range between 3:7, 4:6, 5:5, 6:4, 7:3, or 8:2 for the volume ratio of lead indium niobate-lead magnesium niobate-lead titanate (PIN-PMN-PT) to P(VDF-TrFE), the 0-3 type piezoelectric film is endowed with mechanical flexibility and conformal adhesion to curved surfaces far superior to piezoelectric ceramics. Furthermore, the piezoelectric strain constant of the 0-3 type piezoelectric film is optimized to more than twice that of a single P(VDF-TrFE). Specifically, when the volume ratio of PIN-PMN-PT nanoparticles to P(VDF-TrFE) is 4:6 to 6:4, the piezoelectric strain constant d of the 0-3 type piezoelectric film is significantly higher. 33 The dielectric constant ε ranges from 65 pC / N to 95 pC / N. r <100@1kHz; when the volume ratio of PIN-PMN-PT nanoparticles to P(VDF-TrFE) is 6:4~8:2, the piezoelectric strain constant d of the 0-3 type piezoelectric thin film is... 33 The dielectric constant ε ranges from 95 pC / N to 122 pC / N. r The piezoelectric strain constant d of the 0-3 type piezoelectric thin film can be controlled within the range of 100~400@1kHz. Furthermore, when the volume ratio of PIN-PMN-PT nanoparticles to P(VDF-TrFE) is 6:4~7:3, the piezoelectric strain constant d... 33 The dielectric constant ε ranges from 95 pC / N to 112 pC / N. r The temperature can be controlled within 100~250 kHz. Therefore, by adjusting the composite ratio of PIN-PMN-PT nanoparticles and P(VDF-TrFE), piezoelectric films with different performance focuses can be obtained to meet diverse application requirements.

[0042] Meanwhile, by adjusting the composition ratio of lead indium niobate (PIN), lead magnesium niobate (PMN), and lead titanate (PT) in PIN-PMN-PT nanoparticles, the Curie temperature and piezoelectric voltage constant of PIN-PMN-PT can be better synergistically optimized. The proportion of PIN can be selected from any point or range between 24wt.%, 25wt.%, 26wt.%, 27wt.%, or 28wt.%; the proportion of PMN can be selected from any point or range between 42wt.%, 43wt.%, 44wt.%, 45wt.%, 46wt.%, 47wt.%, or 48wt.%; and the proportion of PT can be selected from any point or range between 26wt.%, 27wt.%, 28wt.%, 29wt.%, 30wt.%, 31wt.%, or 32wt.%.

[0043] Ultimately, the piezoelectric thin film provided by this invention successfully integrates high voltage, high flexibility, and high temperature stability, which can meet the application requirements of high-frequency flexible ultrasonic transducers and high-sensitivity tactile sensors in high-temperature fields and complex scenarios.

[0044] Optionally, the 0-3 type piezoelectric thin film can be configured with different structures according to the application scenario. First, the 0-3 type piezoelectric material layer can be used alone as the 0-3 type piezoelectric thin film, and metal can be deposited on its surface as the electrode of the piezoelectric device. Second, a 0-3 type piezoelectric thin film can be used, comprising a first metal layer, a flexible substrate, and a second metal layer sequentially stacked on the 0-3 type piezoelectric material layer, wherein the first metal layer and the second metal layer are electrically conductive, and the first metal layer and the second metal layer are used together as the lower electrode layer.

[0045] To improve the interfacial compatibility between the inorganic phase and the P(VDF-TrFE) organic phase of PIN-PMN-PT nanoparticles, inhibit the aggregation of PIN-PMN-PT nanoparticles, and thus optimize interfacial breakdown tolerance and stress transfer efficiency, a coupling agent can be used to modify the PIN-PMN-PT nanoparticles. The mass ratio of the PIN-PMN-PT nanoparticles to the coupling agent is 100:1~2. The coupling agent is preferably at least one of polyvinylpyrrolidone, dopamine, organic acid, aminosilane, or epoxysilane. Further, the coupling agent is preferably at least one of 3-aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, oxypyrophosphate titanate, dopamine hydrochloride, oleic acid, or stearic acid.

[0046] Optionally, the average particle size of the PIN-PMN-PT nanoparticles is preferably 200nm~800nm, and can be any value or a range between 200nm, 250nm, 300nm, 350nm, 400nm, 450nm, 500nm, 550nm, 600nm, 650nm, 700nm, 750nm or 800nm. Controlling the particle size of the PIN-PMN-PT nanoparticles in this way can make the PIN-PMN-PT nanoparticles better dispersed in the P(VDF-TrFE) matrix, forming an effective interconnected structure at the microscopic level, and achieving a balance between piezoelectric and mechanical properties at the macroscopic level.

[0047] Optionally, the difference between the maximum and minimum particle size of PIN-PMN-PT nanoparticles is 100nm~300nm. By controlling the difference in particle size of PIN-PMN-PT nanoparticles within this range, in the polarization step of preparing the 0-3 type piezoelectric film, it is possible to ensure that all PIN-PMN-PT nanoparticles are polarized, while avoiding breakdown of the 0-3 type piezoelectric material layer or the generation of a large amount of leakage current. At the same time, by combining PIN-PMN-PT nanoparticles of different sizes, the density of the 0-3 type piezoelectric film can be further improved and the porosity of the P(VDF-TrFE) matrix can be reduced.

[0048] Optionally, the thickness of the 0-3 type piezoelectric material layer is preferably 10μm to 100μm. Within this thickness range, its breakdown voltage withstand capability and mechanical flexibility can be better balanced.

[0049] Optionally, the thicknesses of the first metal layer and the second metal layer are independently selected from 50nm to 200nm, and can be any value or a range between 50nm, 70nm, 100nm, 120nm, 150nm, 170nm or 200nm. The first metal layer and the second metal layer are independently selected from at least one of gold, aluminum or platinum. Such selection can make the first metal layer and the second metal layer have better conductivity.

[0050] Optionally, the thickness of the flexible substrate is preferably 20μm to 200μm, and can be any value or a range between 20μm, 40μm, 60μm, 80μm, 100μm, 120μm, 140μm, 160μm, 180μm or 200μm. The flexible substrate is preferably at least one of polyimide substrate, polyetheretherketone substrate or polyetherimide substrate.

[0051] A method for preparing a 0-3 type piezoelectric thin film as described above includes the following steps: depositing a first metal layer and a second metal layer on the upper and lower surfaces of a flexible substrate, respectively, and making the first metal layer and the second metal layer electrically conductive; performing surface activation treatment on the first metal layer; coating the activated first metal layer to form a 0-3 type piezoelectric material layer; performing hot pressing treatment, and then simultaneously performing polarization and annealing treatment.

[0052] To improve the adhesion between the 0-3 type piezoelectric material layer and the first metal layer, the surface activation treatment is preferably plasma treatment. The plasma treatment is carried out in a reaction chamber, and the process parameters include: vacuum degree of 10Pa~100Pa, power of 50W~500W, and air is introduced into the reaction chamber for activation for 5min~10min.

[0053] Optionally, a type 0-3 piezoelectric material layer is formed by coating the activated first metal layer with a type 0-3 piezoelectric material sol, preferably with a coating amount of 0.25 mL / cm². 2 ~0.40mL / cm 2 The coating method is not limited and spin coating can be used. The specific process of spin coating is as follows: First, spin coating is performed at 250 rpm to 500 rpm for 5 to 10 seconds to form a preliminary liquid film; then spin coating is performed at 800 rpm to 1000 rpm for 10 to 20 seconds to form a uniform thin film; finally, the obtained film is dried at 60℃ to 80℃ for 60 to 120 minutes to ensure that the solvent is completely evaporated. A circular 0-3 type piezoelectric material layer can be obtained by spin coating, and its diameter is preferably 2 inches, 4 inches, 6 inches or 8 inches.

[0054] The preparation method of the 0-3 type piezoelectric material sol is as follows: P(VDF-TrFE) powder is mixed with acetone or N,N-dimethylformamide (DMF) solvent at 60℃~80℃ for 60min~120min. After ultrasonic dispersion, PIN-PMN-PT nanoparticles are added, with a volume ratio of PIN-PMN-PT nanoparticles to P(VDF-TrFE) of 3:7~8:2. The mixture is then stirred at 60℃~80℃ for 60min~120min. Finally, ultrasonic dispersion is performed at 40W~60W power for 40min~60min to obtain a uniform 0-3 type piezoelectric material sol. This method effectively promotes the uniform distribution of PIN-PMN-PT nanoparticles in the P(VDF-TrFE) matrix, thereby reducing particle agglomeration and pore defects in the final 0-3 type piezoelectric material layer.

[0055] Furthermore, the PIN-PMN-PT nanoparticles can be modified using a coupling agent. The preparation steps include: S1, placing the PIN-PMN-PT nanoparticles in a 20 vol.% to 60 vol.% H2O2 solution at a concentration of 0.5 g / mL at 60℃ to 80℃, and activating them by stirring for 4 to 6 hours; after activation, separating, washing, drying, and grinding are performed sequentially to obtain activated PIN-PMN-PT nanoparticles; S2, dissolving the activated PIN-PMN-PT nanoparticles in an ethanol solvent at a concentration of 0.5 g / mL, ultrasonically dispersing them for 60 to 120 minutes, then adding a coupling agent and stirring at 40℃ to 60℃ for 2 to 4 hours, centrifuging, and ultrasonically washing with ethanol for 30 to 60 minutes; repeating steps S1 and S2 3 to 7 times, and finally drying the product at 80℃ to 100℃ and grinding it to a particle size of 200 nm to 800 nm to obtain modified PIN-PMN-PT nanoparticles.

[0056] To improve the density and uniformity of the 0-3 type piezoelectric film, the hot pressing process can optionally be as follows: heating to 140℃~160℃ at a rate of 5℃ / min~10℃ / min, then applying a pressure of 20MPa~60MPa, holding the pressure and temperature for 30min~60min, and then holding the pressure and cooling naturally to room temperature.

[0057] Optionally, the simultaneous polarization and annealing treatment can be carried out using a non-contact gated corona polarization method. This process is performed at 140℃~160℃, at which point the P(VDF-TrFE) matrix is ​​in a molten state, while the PIN-PMN-PT nanoparticles remain solid. In this state, an electric field of 1.0MV / m~2.0MV / m is applied and maintained for 90min~120min. Under the drive of the electric field, the dipole moment of the PIN-PMN-PT nanoparticles is more easily aligned along the direction of the electric field. After cooling, the electric field is turned off, and the PIN-PMN-PT nanoparticles form a stable orientation structure.

[0058] Compared with the traditional two-step process of "annealing first and then polarization", the polarization and annealing synchronous processing technology adopted in this invention achieves synergistic simplification of process and performance improvement through the coupling effect of external electric field and temperature field. The specific advantages are as follows: (1) The polarization efficiency and quality are significantly improved. During the application of polarization electric field, thermodynamic driving force is provided simultaneously, which promotes the in-situ and preferential arrangement of electric domains along the direction of electric field; (2) The uniformity and stability of 0-3 type piezoelectric film are improved, avoiding the Joule heating and breakdown risk caused by local high current density in traditional polarization; (3) The process integration and energy consumption are reduced. The two independent processes of annealing and polarization are combined into one, which simplifies the process flow, shortens the production cycle, and effectively reduces the energy consumption per unit product by avoiding the secondary heating and cooling process.

[0059] The present invention also provides an application of the 0-3 type piezoelectric film in piezoelectric devices.

[0060] The technical solution of the present invention will be further described below through specific embodiments. However, those skilled in the art will understand that the following embodiments are only for illustrating the present invention and should not be regarded as limiting the scope of the present invention. Unless otherwise specified, specific conditions in the embodiments are performed under conventional conditions or conditions recommended by the manufacturer. Reagents or instruments used without specified manufacturers are all commercially available conventional products.

[0061] Example 1

[0062] Preparation of modified PIN-PMN-PT nanoparticles: S1, 50g of PIN-PMN-PT nanoparticles with PIN, PMN and PT ratios of 25wt.%, 45wt.%, and 30wt.% respectively were dispersed in 100mL of 20vol.% H2O2 solution at 60℃ and magnetically stirred for 4h. Then, the nanoparticles were separated, washed, dried and ground sequentially to obtain activated PIN-PMN-PT nanoparticles. S2, 50g of activated PIN-PMN-PT nanoparticles were dissolved in 100mL of ethanol and ultrasonically dispersed for 60min. Then, 0.8g of 3-aminopropyltriethoxysilane coupling agent was added and stirred at 40℃ for 2h. After centrifugation, the nanoparticles were ultrasonically washed with ethanol for 30min. Steps S1 and S2 were repeated three times. Finally, the product was dried at 80℃ and ground to a maximum particle size of 900nm and a minimum particle size of 100nm to obtain modified PIN-PMN-PT nanoparticles with an average particle size of 500nm.

[0063] Preparation of 0-3 type piezoelectric material sol: P(VDF-TrFE) powder was added to DMF at a mass ratio of 1:8, and the mixture was stirred at 60℃ for 60 min. After ultrasonic dispersion, PIN-PMN-PT nanoparticles were added at a volume ratio of 5:5 to P(VDF-TrFE), and the mixture was stirred at 60℃ for 60 min. Finally, the mixture was further dispersed by ultrasonic disruption at 40W power for 60 min to obtain 0-3 type piezoelectric material sol.

[0064] Prepare a polyimide substrate with a thickness of 100 μm and a diameter of 2 inches, and then deposit a first gold layer and a second gold layer of 200 nm on the upper and lower surfaces of the polyimide substrate, respectively.

[0065] First metal layer surface activation treatment: The polyimide substrate covering the first gold layer and the second gold layer is placed in the reaction chamber. Under the conditions of vacuum degree of 100Pa and power of 50W, air is introduced into the reaction chamber for 5 minutes to activate the first gold layer by plasma surface activation treatment.

[0066] Preparation of the 0-3 type piezoelectric material layer: A 0-3 type piezoelectric material sol was uniformly dropped onto the central area of ​​the activated first metal layer surface. The spin coater speed was increased to 250 rpm and maintained for 5 seconds to form a preliminary liquid film. Subsequently, the spin coater speed was increased to 800 rpm and maintained for 10 seconds to form a uniform thin film with a coating amount of 0.35 mL / cm². 2 Then, it was dried at 60°C for 60 min to obtain a 50 μm thick circular 0-3 type piezoelectric material layer on the surface of the first gold layer.

[0067] Hot pressing treatment: Place the above film on the surface of the lower platen, heat the upper and lower plates to 140°C at a rate of 5°C / min, then apply a pressure of 20MPa, hold the pressure and temperature for 30min, and then let it cool naturally to room temperature.

[0068] Synchronous polarization and annealing: The thin film was polarized by gated corona polarization. An electric field of 1.0 MV / m was applied at 140℃ and held for 90 min. After cooling, the electric field was turned off to obtain a 0-3 type piezoelectric thin film.

[0069] Figure 1 The image shows the actual 0-3 type piezoelectric film, which exhibits good flexibility. The 0-3 type piezoelectric film was characterized by electron microscopy, as shown below. Figure 2 As shown, PIN-PMN-PT nanoparticles are uniformly dispersed in P(VDF-TrFE).

[0070] Example 2

[0071] Preparation of modified PIN-PMN-PT nanoparticles: S1, 50g of PIN-PMN-PT nanoparticles with PIN, PMN and PT ratios of 28wt.%, 40wt.%, and 32wt.% respectively were dispersed in 100mL of 20vol.% H2O2 solution at 60℃ and magnetically stirred for 4h. Then, the nanoparticles were separated, washed, dried and ground sequentially to obtain activated PIN-PMN-PT nanoparticles. S2, 50g of activated PIN-PMN-PT nanoparticles were dissolved in 100mL of ethanol and ultrasonically dispersed for 60min. Then, 1.0g of stearic acid coupling agent was added and stirred at 40℃ for 2h. After centrifugation, the nanoparticles were ultrasonically washed with ethanol for 30min. Steps S1 and S2 were repeated three times. Finally, the product was dried at 80℃ and ground to a maximum particle size of 1200nm and a minimum particle size of 400nm to obtain modified PIN-PMN-PT nanoparticles with an average particle size of 800nm.

[0072] Preparation of 0-3 type piezoelectric material sol: P(VDF-TrFE) powder was added to DMF at a mass ratio of 1:8, and the mixture was stirred at 60℃ for 60 min. After ultrasonic dispersion, PIN-PMN-PT nanoparticles were added at a volume ratio of 8:2 to P(VDF-TrFE), and the mixture was stirred at 60℃ for 60 min. Finally, the mixture was further dispersed by ultrasonic disruption at 40W power for 60 min to obtain 0-3 type piezoelectric material sol.

[0073] Prepare a polyimide substrate with a thickness of 100 μm and a diameter of 2 inches, and then deposit a first gold layer and a second gold layer of 200 nm on the upper and lower surfaces of the polyimide substrate, respectively.

[0074] First metal layer surface activation treatment: The polyimide substrate covering the first gold layer and the second gold layer is placed in the reaction chamber. Under the conditions of vacuum degree of 100Pa and power of 50W, air is introduced into the reaction chamber for 5 minutes to activate the first gold layer by plasma surface activation treatment.

[0075] Preparation of the 0-3 type piezoelectric material layer: A 0-3 type piezoelectric material sol was uniformly dropped onto the central area of ​​the activated first metal layer surface. The spin coater speed was increased to 250 rpm and maintained for 5 seconds to form a preliminary liquid film. Subsequently, the spin coater speed was increased to 800 rpm and maintained for 10 seconds to form a uniform thin film with a coating amount of 0.35 mL / cm². 2 Then, it was dried at 60°C for 60 min to obtain a 100 μm thick circular 0-3 type piezoelectric material layer on the surface of the first gold layer.

[0076] Hot pressing treatment: Place the above film on the surface of the lower platen, heat the upper and lower plates to 140°C at a rate of 5°C / min, then apply a pressure of 20MPa, hold the pressure and temperature for 30min, and then let it cool naturally to room temperature.

[0077] Synchronous polarization and annealing: The thin film was polarized by gated corona polarization. An electric field of 1.0 MV / m was applied at 140℃ and held for 90 min. After cooling, the electric field was turned off to obtain a 0-3 type piezoelectric thin film.

[0078] Example 3

[0079] Preparation of modified PIN-PMN-PT nanoparticles: S1, 50g of PIN-PMN-PT nanoparticles with PIN, PMN and PT ratios of 24wt.%, 42wt.%, and 34wt.% respectively were dispersed in 100mL of 20vol.% H2O2 solution at 60℃ and magnetically stirred for 4h. Then, the nanoparticles were separated, washed, dried and ground sequentially to obtain activated PIN-PMN-PT nanoparticles. S2, 50g of activated PIN-PMN-PT nanoparticles were dissolved in 100mL of ethanol and ultrasonically dispersed for 60min. Then, 0.5g of pyrophosphate oxytitanate coupling agent was added and stirred at 40℃ for 2h. After centrifugation, the nanoparticles were ultrasonically washed with ethanol for 30min. Steps S1 and S2 were repeated three times. Finally, the product was dried at 80℃ and ground to a maximum particle size of 900nm and a minimum particle size of 100nm to obtain modified PIN-PMN-PT nanoparticles with an average particle size of 200nm.

[0080] Preparation of 0-3 type piezoelectric material sol: P(VDF-TrFE) powder was added to DMF at a mass ratio of 1:8, and the mixture was stirred at 60℃ for 60 min. After ultrasonic dispersion, PIN-PMN-PT nanoparticles were added at a volume ratio of 3:7 to P(VDF-TrFE), and the mixture was stirred at 60℃ for 60 min. Finally, the mixture was further dispersed by ultrasonic crushing at 40W power for 60 min to obtain 0-3 type piezoelectric material sol.

[0081] Prepare a polyimide substrate with a thickness of 100 μm and a diameter of 2 inches, and then deposit a first gold layer and a second gold layer of 200 nm on the upper and lower surfaces of the polyimide substrate, respectively.

[0082] First metal layer surface activation treatment: The polyimide substrate covering the first gold layer and the second gold layer is placed in the reaction chamber. Under the conditions of vacuum degree of 100Pa and power of 50W, air is introduced into the reaction chamber for 5 minutes to activate the first gold layer by plasma surface activation treatment.

[0083] Preparation of the 0-3 type piezoelectric material layer: A 0-3 type piezoelectric material sol was uniformly dropped onto the central area of ​​the activated first metal layer surface. The spin coater speed was increased to 250 rpm and maintained for 5 seconds to form a preliminary liquid film. Subsequently, the spin coater speed was increased to 1000 rpm and maintained for 10 seconds to form a uniform thin film with a coating amount of 0.35 mL / cm². 2 Then, it was dried at 60°C for 60 min to obtain a 10 μm thick circular 0-3 type piezoelectric material layer on the surface of the first gold layer.

[0084] Hot pressing treatment: Place the above film on the surface of the lower platen, heat the upper and lower plates to 140°C at a rate of 5°C / min, then apply a pressure of 20MPa, hold the pressure and temperature for 30min, and then let it cool naturally to room temperature.

[0085] Synchronous polarization and annealing: The thin film was polarized by gated corona polarization. An electric field of 1.0 MV / m was applied at 140℃ and held for 90 min. After cooling, the electric field was turned off to obtain a 0-3 type piezoelectric thin film.

[0086] Example 4

[0087] The only difference between Example 4 and Example 1 is that the modified PIN-PMN-PT nanoparticles obtained have a maximum particle size of 550 nm, a minimum particle size of 450 nm, and an average particle size of 500 nm.

[0088] Example 5

[0089] The only difference between Example 5 and Example 1 is that the modified PIN-PMN-PT nanoparticles obtained have a maximum particle size of 650 nm, a minimum particle size of 350 nm, and an average particle size of 500 nm.

[0090] Example 6

[0091] The only difference between Example 6 and Example 1 is that the proportions of PIN, PMN, and PT in the PIN-PMN-PT nanoparticles are 26 wt.%, 48 wt.%, and 26 wt.%, respectively, and the volume ratio of PIN-PMN-PT nanoparticles to P(VDF-TrFE) is 7:3. In the simultaneous polarization and annealing process, the thin film is polarized using a gated corona polarization method. An electric field of 1.5 MV / m is applied at 160°C and maintained for 120 min. After cooling, the electric field is turned off, and the circular 0-3 type piezoelectric material layer is peeled off from the first gold layer to obtain the 0-3 type piezoelectric thin film.

[0092] Comparative Example 1

[0093] The only difference between Comparative Example 1 and Example 1 is that PZT-5H nanoparticles were used instead of PIN-PMN-PT nanoparticles to prepare the 0-3 type piezoelectric film.

[0094] Comparative Example 2

[0095] The only difference between Comparative Example 2 and Example 1 is that PMN-PT nanoparticles were used instead of PIN-PMN-PT nanoparticles to prepare the 0-3 type piezoelectric film.

[0096] Comparative Example 3

[0097] The only difference between Comparative Example 3 and Example 1 is that PDMS was used instead of P(VDF-TrFE) to prepare the 0-3 type piezoelectric film.

[0098] Comparative Example 4

[0099] The only difference between Comparative Example 4 and Example 1 is that the volume ratio of PIN-PMN-PT nanoparticles to P(VDF-TrFE) is 9:1.

[0100] Comparative Example 5

[0101] The only difference between Comparative Example 5 and Example 1 is that the volume ratio of PIN-PMN-PT nanoparticles to P(VDF-TrFE) is 2:8.

[0102] Comparative Example 6

[0103] The only difference between Comparative Example 6 and Example 1 is that the proportions of PIN, PMN and PT in the PIN-PMN-PT nanoparticles are 40 wt.%, 10 wt.%, and 50 wt.%, respectively.

[0104] The 0-3 type piezoelectric thin films prepared in Examples 1 to 5 and Comparative Examples 1 to 6 were directly tested for piezoelectric performance at 80°C. The gold layer deposited on the surface of the 0-3 type piezoelectric thin film prepared in Example 6 was used as an electrode and tested for piezoelectric performance at 80°C. The results are shown in Table 1.

[0105] Table 1

[0106]

[0107] As can be seen from Table 1, compared with Comparative Examples 1 to 6, the 0-3 type piezoelectric films prepared in Examples 1 to 6 exhibit a high piezoelectric strain constant d under high temperature conditions. 33 and low dielectric constant ε rThat is, the 0-3 type piezoelectric thin film prepared by the present invention achieves synergistic optimization of high voltage strain constant and low dielectric constant; as can be seen from the comparison of Examples 1, 4 and 5, when the difference between the maximum and minimum particle size of PIN-PMN-PT nanoparticles is controlled in the range of 100nm~300nm, its piezoelectric performance is better.

[0108] The piezoelectric thin films of type 0-3 prepared in Example 1 and Comparative Examples 1 to 6 were subjected to piezoelectric thermal stability tests at 110°C. The results are shown in Table 2.

[0109] Table 2

[0110]

[0111] As can be seen from Table 2, by comparing Example 1 with Comparative Examples 1 to 6, the 0-3 type piezoelectric film of the present invention still has good piezoelectric properties under extreme high temperature conditions.

[0112] The 0-3 type piezoelectric films prepared in Example 1 and Comparative Example 3 were subjected to dynamic thermomechanical analysis (DMA), i.e., flexibility test, at 110°C. The results are shown in Table 3.

[0113] Table 3

[0114]

[0115] As can be seen from Table 3, the 0-3 type piezoelectric film prepared in Example 1 has a high storage modulus and a low loss factor under high temperature conditions, while the 0-3 type piezoelectric film prepared in Comparative Example 3 has a lower storage modulus and a higher loss factor under high temperature conditions, making it extremely prone to irreversible deformation and functional failure. That is, the 0-3 type piezoelectric film prepared in this invention exhibits more stable and superior mechanical properties under high temperature working conditions.

[0116] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0117] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A type 0-3 piezoelectric thin film, characterized in that, The 0-3 type piezoelectric film includes at least a 0-3 type piezoelectric material layer, which comprises lead indium niobate-lead magnesium niobate-lead titanate nanoparticles and polyvinylidene fluoride-trifluoroethylene in a volume ratio of 3:7 to 8:

2. The average particle size of the lead indium niobate-lead magnesium niobate-lead titanate nanoparticles is 200nm~800nm, and the difference between the maximum and minimum particle size of the lead indium niobate-lead magnesium niobate-lead titanate nanoparticles is 100nm~300nm. In the aforementioned lead indium niobate-lead magnesium niobate-lead titanate nanoparticles, lead indium niobate accounts for 24 wt.%~28 wt.%, lead magnesium niobate accounts for 42 wt.%~48 wt.%, and lead titanate accounts for 26 wt.%~32 wt.%.

2. The 0-3 type piezoelectric thin film according to claim 1, characterized in that, The 0-3 type piezoelectric thin film further includes a first metal layer, a flexible substrate, and a second metal layer sequentially stacked on the 0-3 type piezoelectric material layer, wherein the first metal layer and the second metal layer are electrically connected.

3. The O-3 type piezoelectric thin film according to claim 2, characterized in that, The thickness of the 0-3 type piezoelectric material layer is 10μm~100μm; And / or, the thicknesses of the first metal layer and the second metal layer are each independently selected from 50 nm to 200 nm; And / or, the thickness of the flexible substrate is 20μm~200μm; And / or, the first metal layer and the second metal layer are each independently selected from at least one of a gold layer, an aluminum layer, or a platinum layer; And / or, the flexible substrate is selected from at least one of polyimide substrate, polyetheretherketone substrate or polyetherimide substrate.

4. The 0-3 type piezoelectric thin film according to claim 1, characterized in that, The lead indium niobate-lead magnesium niobate-lead titanate nanoparticles are modified with a coupling agent, and the mass ratio of the lead indium niobate-lead magnesium niobate-lead titanate nanoparticles to the coupling agent is 100:1~2.

5. The O-3 type piezoelectric thin film according to claim 4, characterized in that, The coupling agent is selected from at least one of polyvinylpyrrolidone, dopamine, organic acid, aminosilane, or epoxysilane.

6. A method for preparing a 0-3 type piezoelectric thin film as described in any one of claims 1 to 5, characterized in that, Includes the following steps: A first metal layer and a second metal layer are deposited on the upper and lower surfaces of a flexible substrate, respectively, and the first metal layer and the second metal layer are electrically connected. The first metal layer is subjected to surface activation treatment; A type 0-3 piezoelectric material layer is prepared on the activated first metal layer; Hot pressing is performed, followed by simultaneous polarization and annealing.

7. The method for preparing a 0-3 type piezoelectric thin film according to claim 6, characterized in that, The preparation method also satisfies at least one of the following conditions: (1) The surface activation treatment is plasma treatment, which is carried out in a reaction chamber. The process parameters are: vacuum degree of 10Pa~100Pa, power of 50W~500W, and air is introduced into the reaction chamber for activation for 5min~10min. (2) A type 0-3 piezoelectric material layer is prepared on the activated first metal layer using a type 0-3 piezoelectric material sol, wherein the coating amount of the type 0-3 piezoelectric material sol is 0.25 mL / cm. 2 ~0.40mL / cm 2 The 0-3 type piezoelectric material sol includes lead indium niobate-lead magnesium niobate-lead titanate nanoparticles, polyvinylidene fluoride-trifluoroethylene and solvent; (3) The process parameters of the hot pressing treatment include: heating to 140℃~160℃ at a rate of 5℃ / min~10℃ / min, then applying a pressure of 20MPa~60MPa and holding the pressure and temperature for 30min~60min; (4) The polarization and annealing treatment is carried out by gate-controlled corona polarization, with an electric field of 1.0MV / m to 2.0MV / m applied at a temperature of 140℃ to 160℃ for 90min to 120min.

8. The method for preparing a type 0-3 piezoelectric thin film according to claim 7, characterized in that, The lead indium niobate-lead magnesium niobate-lead titanate nanoparticles are modified with a coupling agent, and the preparation steps include: S1, lead indium niobate-lead magnesium niobate-lead titanate nanoparticles are activated in H2O2 solution; S2, the activated lead indium niobate-lead magnesium niobate-lead titanate nanoparticles, coupling agent and solvent are mixed and stirred; Repeat steps S1 and S2 3 to 7 times, and then dry and grind the final product.

9. The application of a 0-3 type piezoelectric thin film as described in any one of claims 1 to 5 in a piezoelectric device.

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