CN116782740A - Piezoelectric film, preparation method thereof, piezoelectric device and display device - Google Patents

Abstract

The embodiment of the disclosure provides a piezoelectric film, a preparation method of the piezoelectric film, a piezoelectric device, a preparation method of the piezoelectric device and a display device. Specifically, embodiments of the present disclosure provide a method of preparing a piezoelectric thin film, including: mixing piezoelectric material particles with a carrier gas to form an aerosol; spraying the aerosol on a substrate to form a prefabricated layer; heating the prefabricated layer to form the piezoelectric film, wherein the particle size of the piezoelectric material particles is 0.2-1 mu m; the temperature of the heating treatment is not higher than 500 ℃. Therefore, the method directly takes the piezoelectric material particles as raw materials to form the piezoelectric film, can obtain the piezoelectric film with excellent performance without high-temperature heat treatment, and is particularly suitable for forming the piezoelectric film on the glass substrate; the method has the advantages of large deposition film thickness range, high deposition speed, small film stress, low process temperature, large-area deposition and the like.

Description

Piezoelectric film, preparation method thereof, piezoelectric device and display device

Technical Field

The disclosure relates to the technical field of display, in particular to a piezoelectric film, a preparation method, a piezoelectric device and a display device.

Background

The piezoelectric material is a crystal material which generates voltage between two end surfaces when being subjected to pressure, and the piezoelectric material can realize the interconversion of mechanical vibration (sound wave) and alternating current. Lead zirconate titanate (PZT) ceramic material has high dielectric constant and spontaneous polarization intensity, and is an important piezoelectric material, and is commonly used for preparing sensors and drivers. PZT piezoelectric films are widely used, including but not limited to tactile sensing and driving elements, miniature microphones and speakers, inkjet printheads, and the like using PZT films.

However, the existing piezoelectric thin film, the preparation method, the piezoelectric device and the display device still need to be improved.

Disclosure of Invention

The embodiment of the disclosure provides a piezoelectric film, a preparation method of the piezoelectric film, a piezoelectric device, a preparation method of the piezoelectric device and electronic equipment, and aims to solve or alleviate one or more technical problems in the related art.

As a first aspect of embodiments of the present disclosure, embodiments of the present disclosure provide a method of preparing a piezoelectric film, the method comprising: mixing piezoelectric material particles with a carrier gas to form an aerosol; spraying the aerosol on a substrate to form a prefabricated layer; heating the prefabricated layer to form the piezoelectric film, wherein the particle size of the piezoelectric material particles is 0.2-1 mu m; the temperature of the heating treatment is not higher than 500 ℃.

In one embodiment, the material forming the piezoelectric material particles comprises: lead zirconate titanate.

In one embodiment, the forming the aerosol further comprises: mixing the piezoelectric material particles, additives, and the carrier gas; the material forming the additive comprises lead oxide, and the content of the additive in the aerosol is 5mol at% to 15mol at%.

In one embodiment, the method further comprises: placing the piezoelectric material particles into a first vibrating cavity to suspend the piezoelectric material particles; introducing the carrier gas into the first cavity, and mixing the piezoelectric material particles with the carrier gas to form the aerosol; the aerosol is sprayed into a second cavity communicated with the first cavity and deposited on the substrate in the second cavity to form the prefabricated layer.

In one embodiment, there is a pressure difference between the first and second chambers, the pressure difference being 50-101kPa.

In one embodiment, the spraying is achieved by means of a nozzle, the opening of which has a diameter of 0.5-1mm.

In one embodiment, the substrate is configured to be movable in at least one of a first direction and a second direction, the substrate moving at a rate of 2-10mm/sec in the first and second directions, respectively, independently;

the first direction and the second direction are perpendicular to each other.

In one embodiment, the rate of movement is controlled such that the aerosol is deposited on the substrate at a deposition rate of 5-50 μm/min.

As a second aspect of the present disclosure, a piezoelectric film prepared by the method described above is proposed.

In one embodiment, the piezoelectric film has a thickness of 500nm to 1mm.

As a third aspect of the present disclosure, there is provided a piezoelectric device including: a substrate; a first electrode disposed at one side of the substrate; a piezoelectric film disposed on a side of the first electrode remote from the substrate, the piezoelectric film being as described above; and the second electrode is arranged on one side of the piezoelectric film away from the first electrode.

In one embodiment, the piezoelectric device satisfies at least one of the following conditions: the material forming the substrate comprises glass, and the material forming at least one of the first electrode and the second electrode comprises a transparent conductive material; the thickness of the first electrode and the second electrode is 200-600nm.

In one embodiment, the piezoelectric device further comprises a seed layer disposed between the first electrode and the piezoelectric film, the seed layer satisfying at least one of the following conditions: the material forming the seed layer comprises PbTiO ₃ 、PbZrO ₃ The seed layer has a thickness of 5nm to 20nm.

As a fourth aspect of the present disclosure, there is provided a method of manufacturing a piezoelectric device, the method comprising: providing a substrate; forming a first electrode on the substrate; forming a piezoelectric film on a side of the first electrode away from the substrate, the piezoelectric film being prepared by the method described above; a second electrode is formed on a side of the piezoelectric film away from the first electrode.

In one embodiment, after forming the first electrode, before forming the piezoelectric film, the method further comprises: a seed layer is formed on a side of the first electrode remote from the substrate.

As a fifth aspect of the present disclosure, there is provided a display apparatus including the piezoelectric device described above.

Drawings

In the drawings, the same reference numerals refer to the same or similar parts or elements throughout the several views unless otherwise specified. The figures are not necessarily drawn to scale. It is appreciated that these drawings depict only some embodiments according to the disclosure and are not to be considered limiting of its scope.

FIG. 1 is a schematic diagram of a method of preparing a piezoelectric film according to one embodiment of the present disclosure;

FIG. 2 is a schematic diagram of a method of fabricating a piezoelectric film according to another embodiment of the present disclosure;

FIG. 3 is a schematic diagram of a method of fabricating a piezoelectric film according to another embodiment of the present disclosure;

FIG. 4 is a schematic diagram of a piezoelectric device according to one embodiment of the present disclosure;

fig. 5 is a schematic structural view of a piezoelectric device according to another embodiment of the present disclosure;

FIG. 6 is a schematic diagram of a method of fabricating a piezoelectric device according to one embodiment of the present disclosure;

fig. 7 is a schematic diagram of a method of fabricating a piezoelectric device according to another embodiment of the present disclosure.

Reference numerals illustrate:

100: a first cavity; 200: a second cavity; 10: particles of piezoelectric material; 20: a carrier gas; 30: a nozzle; 40: a substrate; 1000: a piezoelectric device; 1100: a substrate; 1200: a first electrode; 1300: a piezoelectric film; 1400: a second electrode; 1500: a seed layer.

Detailed Description

Hereinafter, only certain exemplary embodiments are briefly described. As will be recognized by those of skill in the pertinent art, the described embodiments may be modified in various different ways, and the different embodiments may be combined arbitrarily without conflict, without departing from the spirit or scope of the present disclosure. Accordingly, the drawings and description are to be regarded as illustrative in nature and not as restrictive.

In a first aspect of the present disclosure, the present disclosure proposes a method of preparing a piezoelectric thin film by an aerosol method directly using piezoelectric material particles (e.g., PZT particles) as a raw material. The components of the piezoelectric material particles are near a quasi-type phase boundary (MPB) phase region by controlling the piezoelectric material particles, so that the piezoelectric material particles have good piezoelectric performance, and aerosol is formed by using the piezoelectric material particles to prepare the piezoelectric film. In the process of preparing the piezoelectric film by the aerosol method, the particles of the piezoelectric material are deposited on the substrate in the form of a whole single crystal, so that the piezoelectric film with good performance can be obtained without a high-temperature heat treatment process. In the conventional piezoelectric film obtained by sol-gel method, the material used for forming PTZ in the raw material is in an ionic form, and the PTZ is formed by chemical reaction of sol-gel slurry during the forming process, and thus annealing treatment is required. Compared with the traditional sol-gel method for preparing the piezoelectric film, the aerosol method has no ion diffusion process when preparing the piezoelectric film, avoids the piezoelectric performance reduction caused by component deviation, and the temperature of heating treatment is usually lower than the softening point temperature of glass, thus being particularly suitable for forming the piezoelectric film on a glass substrate; the method has the advantages of large deposition film thickness range, high deposition speed, small film stress, low process temperature, large-area deposition and the like.

Specifically, referring to fig. 1, the method may include the steps of:

s100, mixing piezoelectric material particles with carrier gas to form aerosol

In this step, the piezoelectric material particles and the carrier gas are mixed to form an aerosol. In some embodiments of the application, the material forming the piezoelectric material particles may include lead zirconate titanate (PZT), and the carrier gas may be an inert gas such as nitrogen, argon, helium, or the like.

When the aerosol method is adopted to prepare the piezoelectric film, the PZT piezoelectric material particles are directly taken as raw materials, and the PZT piezoelectric material particles are directly deposited on a substrate in a molecular form, such as a whole single crystal form, in the preparation process, so that an ion diffusion process is avoided. The piezoelectric film obtained by the method does not need a high-temperature annealing process, and the temperature required in the whole processing process is far lower than the softening point temperature of materials such as glass and the like, so that the piezoelectric film can be directly formed on the substrate such as glass and the like. The piezoelectric film has the characteristics of small film stress, large-area deposition and the like, and the prepared piezoelectric film has good performance.

In some embodiments of the application, the particles of piezoelectric material may have a particle size of 0.2-1 μm, for example, 0.3 μm,0.35 μm,0.4 μm,0.45 μm,0.5 μm,0.55 μm,0.6 μm,0.7 μm,0.8 μm,0.9 μm,0.99 μm, etc. When the particle diameter of the piezoelectric material particles is in the above range, the particles themselves are easily polarized, and the piezoelectric material particles have good ferroelectric properties. In turn, the particles of piezoelectric material may be deposited on the substrate in the form of a single crystal throughout the subsequent fabrication process. Only small lattice distortion can be caused in the deposition process, the lattice distortion can be recovered at lower energy and temperature, namely, an ordered crystal structure can be recovered through low-temperature annealing, and a piezoelectric film with good ferroelectric property is formed. The method does not need to form new crystal phase during heating treatment, so the energy is small and the heating temperature is low. Specifically, when the particle size of the piezoelectric material particles is smaller than 0.2 μm, the kinetic energy of the piezoelectric material particles is lower, and the piezoelectric material particles directly bounce after striking the substrate and cannot adhere to the substrate; when the particle diameter of the piezoelectric material particles is larger than 1 μm, the particles are hardly broken, a thin film of a porous structure is formed, and the density and quality of the film layer are poor.

As described above, in the case of the conventional sol-gel method for producing a piezoelectric thin film, the raw material is decomposed into molecular ions and recrystallized on the substrate. Thus, to achieve good piezoelectric constant characteristics, the PZT piezoelectric thin film needs to undergo PZT grain growth in an air environment of more than 650 ℃. It is apparent that the above temperature is higher than the softening temperature of the substrate such as glass on the one hand, and thus cannot be directly achieved when the PZT piezoelectric film needs to be grown on the substrate such as glass, and the means for transferring the film is not mature and causes damage to the flatness of the film. In addition, the boundary defects among grains in the PZT thin film obtained by forming a thin film and then performing grain growth are difficult to effectively control, and the obtained film has larger stress.

In some embodiments of the application, forming the aerosol may further comprise: the piezoelectric material particles, additives and carrier gas are mixed. Specifically, the material forming the additive may include lead oxide (PbO), whereby the addition of PbO may increase adhesion between PZT piezoelectric material particles during subsequent ejection and deposition of the piezoelectric material particles, and may compensate for reduction in Pb volatilization and O vacancies generated by subsequent heat treatment, so that the prepared piezoelectric thin film has excellent piezoelectric properties. Specifically, the content of the additive in the formed aerosol may be 5mol at% to 15mol at% (mol at% i.e. mole mass fraction), specifically may be 7mol at%, 8mol at%, 9mol at%, 10mol at%, 12mol at%, 14mol at%, etc. Thus, when the content of the additive is within the above range, it is possible to better increase the adhesiveness between PZT piezoelectric material particles and to compensate for the reduction of Pb volatilization and O vacancies generated by the subsequent heat treatment. Specifically, when the content of the additive is more than 15mol at%, the adhesion is excessive and the non-PZT active ingredient is small, affecting the piezoelectric performance. While an excessively small content of the additive cannot exert an effect of increasing the adhesiveness.

In some embodiments of the application, referring to fig. 2, the method further comprises:

s110, placing the piezoelectric material particles into a first vibrating cavity to suspend the piezoelectric material particles

In this step, the piezoelectric material particles are placed in a vibrating first cavity, and the piezoelectric material particles are suspended. Specifically, the first cavity can vibrate continuously, so that the particles of the piezoelectric material in the first cavity can be suspended uniformly, and subsequent mixing with carrier gas to form uniform aerosol is facilitated.

S120, introducing carrier gas into the first cavity, mixing the piezoelectric material particles with the carrier gas to form aerosol

In this step, a carrier gas is passed into the first cavity, and the piezoelectric material particles and the carrier gas are mixed to form an aerosol. Specifically, the rate of introducing the carrier gas may be 4-10L/min, whereby the piezoelectric material particles may be sufficiently mixed with the carrier gas uniformly, and by controlling the rate of introducing the carrier gas, the rate of aerosol deposition may be controlled, and further the film thickness, roughness, etc. of the formed piezoelectric film may be controlled.

S200, spraying aerosol on the substrate to form a prefabricated layer

In this step, the aerosol formed in the above step is sprayed on the substrate to form a preformed layer. In some embodiments of the application, referring to fig. 3, particles of piezoelectric material 10 are suspended in a first cavity 100 and mixed with a carrier gas 20 to form an aerosol, which may be ejected through a nozzle 30 into a second cavity 200 in communication with the first cavity 100 and deposited on a substrate 40 positioned in the second cavity 200 to form a preformed layer.

In some embodiments of the present application, there is a pressure differential between the first chamber 100 and the second chamber 200, whereby the pressure differential between the first chamber 100 and the second chamber 200 may accelerate the piezoelectric material particles 10, forcing the piezoelectric material particles 10 to be ejected from the second chamber 200, such as through the nozzle 30 of the second chamber 200, and deposited onto the substrate 40 at a high rate. Specifically, the pressure in the second chamber may be greater than the pressure in the first chamber, for example, the pressure in the second chamber may be 500to 2000 times the pressure in the first chamber, more specifically, the pressure in the first chamber where the aerosol is formed is 100 to 500Torr, and the pressure in the second chamber where the PZT thin film is deposited may be 0.2 to 2Torr. Thus, when the pressure difference between the first chamber 100 and the second chamber 200 is within the above range, the ejection and deposition of the piezoelectric material particles 10 can be better promoted, further improving the performance of the prepared piezoelectric thin film. Specifically, the first cavity 100 may be in a conventional atmospheric pressure state, and the vacuum pump may be used to decompress the second cavity 200, so that a large pressure difference may be simply provided between the first cavity 100 and the second cavity 200, so as to facilitate the injection and deposition of the piezoelectric material particles 10, and further improve the performance of the prepared piezoelectric film. As mentioned above, since the method of the present application uses aerosol as raw material to deposit PZT, the high temperature annealing process is not involved, and the heat treatment temperature in the whole process can be controlled below the softening point temperature of glass and other materials. Therefore, when it is necessary to form a PZT thin film on a conductive electrode, the method proposed by the present application can be formed directly on an electrode having a substrate of a relatively high rigidity such as glass or the like thereunder. For example, a film layer such as ITO may be formed on the surface of glass as an electrode, and the film may be formed directly on the electrode surface by aerosol spraying. Unlike the technology of rigid support substrate such as glass, the method provided by the application can ignore the impact of aerosol spraying process to the conductive film layer, so that the negative effect of controlling aerosol spraying rate to the substrate or the electrode is not needed.

In some embodiments of the present application, the specific shape and size of the nozzle 30 are not particularly limited, and may be selected as desired by those skilled in the art. For example, the shape, size of the nozzle may be configured to advantageously accelerate the aerosol. Specifically, the nozzle 30 may be slit-shaped, and the opening diameter of the nozzle 30 may be 0.5 to 1mm, for example, may be 0.6mm, may be 0.7mm, may be 0.8mm, may be 0.9mm, etc., whereby, when the diameter of the nozzle 30 is in the above-described range, acceleration and ejection of the piezoelectric material fine particles 10 are facilitated, the piezoelectric material fine particles 10 conveyed by the carrier gas are easily accelerated to several hundred m/sec, the deposition rate of the piezoelectric material fine particles 10 is improved, and the preparation rate of the piezoelectric thin film is further improved.

In some embodiments of the application, the substrate 40 may be moved within the second chamber. Thereby, the area of the PZT film layer formed can be further increased. For example, the substrate 40 may be moved in at least one of the first direction and the second direction. In some examples, the first direction may be an x-direction and the second direction may be a y-direction. That is, the substrate 40 may be moved in two directions perpendicular to each other, for example, by being carried through an X-Y movement stage. Typically, the substrate 40 is a planar rectangular sheet, so that both X-Y directions may define a deposition surface of the substrate 40. Thereby, the piezoelectric thin film can be conveniently deposited on the entire substrate 40. And, the deposition rate and roughness of the deposited PZT layer can be easily controlled using the flow rate of the carrier gas and the scanning speed of the X-Y movement stage.

The deposition rate of the aerosol on the substrate may be controlled by a variety of means, such as by controlling the rate of aerosol ejection at the nozzle, and the rate of movement of the substrate 40 in the first and second directions described above. In some embodiments, the deposition rate may be controlled by adjusting the rate of movement of the substrate 40. The movement rate of the substrate in the first and second directions may be 2to 10mm/sec, for example, 2.5mm/sec,3mm/sec,3.5mm/sec,4mm/sec,4.5mm/sec,5mm/sec,5.5mm/sec,6mm/sec,7mm/sec,8mm/sec,9mm/sec, 10mm/sec, or the like, independently. The aerosol deposition rate may be 5-50 μm/min, for example, 10 μm/min, 15 μm/min, 20 μm/min, 25 μm/min, 30 μm/min, 32 μm/min, 35 μm/min, 37 μm/min, 40 μm/min, 42 μm/min, 45 μm/min, 47 μm/min, etc. Thus, according to the method of the embodiment of the application, the aerosol deposition rate is high, and the piezoelectric film is prepared efficiently. The film forming time of the traditional magnetron sputtering method is 0.01-0.07 mu m/min, and the deposition rate of the method provided by the application is obviously higher than that of the traditional sputtering method.

S300, heating the prefabricated layer to form the piezoelectric film

In this step, the prefabricated layer prepared in the previous step is subjected to a heat treatment to form a piezoelectric thin film. Specifically, as described above, according to the method of the embodiment of the present application, the piezoelectric material particles are deposited on the substrate in the form of a single crystal through plastic deformation in a high-speed impact, and thus only a minute lattice distortion is caused during the deposition, and therefore, the ordered crystal structure can be recovered only by a low-temperature heat treatment in the subsequent process, that is, the piezoelectric thin film excellent in performance can be obtained without a high-temperature heat treatment in the subsequent process. Specifically, the temperature of the heat treatment may be not higher than 500 ℃, for example, 350 to 500 ℃, 400 ℃, 420 ℃, 430 ℃, 450 ℃, 470 ℃, etc., and thus, a piezoelectric film excellent in performance can be produced at a relatively low temperature, and the above temperature is usually lower than the softening point temperature of glass, and is particularly suitable for forming a piezoelectric film on a glass substrate.

In a second aspect of the present disclosure, the present disclosure provides a piezoelectric film that may be prepared by the method described previously. Thus, the piezoelectric film has all the features and advantages of the piezoelectric film prepared by the method described above, and will not be described herein.

In some embodiments of the application, the piezoelectric film may have a thickness of 500nm-1mm, for example, 1 μm, 10 μm, 100 μm, 500 μm, 800 μm, or the like. As described above, the piezoelectric film is formed by aerosol, and the PZT material is contained in the aerosol stage, so that the thickness of the film can be realized by aerosol deposition, and the better film quality can be ensured. Thus, the piezoelectric film prepared according to the method has wide thickness range, high preparation efficiency and good performance.

In a third aspect of the present disclosure, the present disclosure proposes a piezoelectric device, referring to fig. 4, the piezoelectric device 1000 may include: the piezoelectric thin film 1300 is prepared by the method described above, and therefore, the piezoelectric thin film 1300 in the piezoelectric device 1000 has all the features and advantages of the piezoelectric thin film prepared by the method described above, and the details are not repeated here. The piezoelectric device has good performance and simple preparation process.

In some embodiments of the present application, the material forming the substrate 1100 may include glass, and the material forming the first electrode 1200 and the second electrode 1400 may include a transparent conductive material, such as Indium Tin Oxide (ITO), indium Zinc Oxide (IZO), or the like. As described above, when the piezoelectric film is prepared by the method according to the embodiment of the application, the temperature of the heating treatment is lower, usually lower than the softening temperature of glass, and the method is particularly suitable for preparing the piezoelectric film on a glass substrate, so that the piezoelectric device can be simply and conveniently made into a full-transparent device, and further can be integrated with a display product, and the service performance of the product is further improved. In addition, compared with the traditional metal electrode, the electrode film layer formed by the method has the advantages that the material cost is low, such as Indium Tin Oxide (ITO) and Indium Zinc Oxide (IZO), is firm, and the problems of electrode deformation and the like caused by high-speed particle injection when the piezoelectric film is prepared by the aerosol method can be effectively avoided.

In some embodiments of the present application, the thickness of the first electrode 1200 and the second electrode 1400 may be 200-600nm, for example, 300nm, 350nm, 400nm, 450nm, 500nm, 550nm, etc., and thus, when the thickness of the first electrode 1200 and the second electrode 1400 is in the above range, the electrode conductivity is good and warp deformation is not easily generated. When the thickness of the first electrode 1200 and the second electrode 1400 is less than 200nm, the electrodes are thinner and the conductivity is poor; when the thicknesses of the first electrode 1200 and the second electrode 1400 are greater than 600nm, too thick stress of the electrodes is large, and the electrode film is easily deformed by warpage.

In one embodiment, referring to fig. 5, the piezoelectric device 1000 may further include: a seed layer 1500, the seed layer 1500 being disposed between the first electrode 1200 and the piezoelectric film 1300; in particular, the material forming the seed layer may include PbTiO ₃ 、PbZrO ₃ At least one of the (c) and (d),thus, the seed layer 1500 can reduce the mismatch between the lattice of the piezoelectric film 1300 (e.g., PZT piezoelectric film) and the lattice of the first electrode 1200 (e.g., ITO), reduce the mismatch of thermal expansion coefficients due to local temperature, and further improve the piezoelectric performance and the usability of the piezoelectric device. Specifically, the thickness of the seed layer 1500 may be between 5nm and 20nm, for example, may be 8nm, may be 10nm, may be 12nm, may be 15nm, may be 17nm, etc., and thus, when the thickness of the seed layer 1500 is in the above range, the mismatch between the lattice of the piezoelectric film 1300 (e.g., PZT piezoelectric film) and the lattice of the first electrode 1200 (e.g., ITO) may be preferably reduced, further improving the piezoelectric performance and the usability of the piezoelectric device.

In a fourth aspect of the present disclosure, a method for manufacturing a piezoelectric device is provided, where the piezoelectric device manufactured by the method may be the piezoelectric device described above, and thus, the piezoelectric device manufactured by the method has all the features and advantages of the piezoelectric device described above, which are not described herein.

In some embodiments of the application, referring to fig. 6, the method may include:

s1000 providing a substrate

In this step, a substrate, specifically, a glass substrate is provided.

S2000 formation of first electrode

In this step, the first electrode is formed on the aforementioned substrate, and specifically, the first electrode may be formed by a magnetron sputtering method or a sol-gel method. The material forming the first electrode may include transparent conductive material, such as Indium Tin Oxide (ITO), indium Zinc Oxide (IZO), etc., and the electrode film layer formed by the electrode material is relatively firm, so that the problem of electrode deformation caused by high-speed particle spraying when the piezoelectric film is prepared by an aerosol method in the following process can be effectively avoided. Specifically, the temperature at which the first electrode is formed is lower than the softening point temperature of the glass substrate.

S3000 formation of piezoelectric film

In this step, a piezoelectric film, which may be prepared by the method described above, that is, a piezoelectric film may be formed by an aerosol method, is formed on the side of the first electrode remote from the substrate. The method directly takes the piezoelectric material particles as raw materials to form the piezoelectric film, can obtain the piezoelectric film with excellent performance without high-temperature heat treatment, and is particularly suitable for forming the piezoelectric film on a glass substrate; the method has the advantages of large deposition film thickness range, high deposition speed, small film stress, low process temperature, large-area deposition and the like.

S4000 forming a second electrode

In this step, the second electrode is formed on the side of the piezoelectric film away from the first electrode, and in particular, the second electrode may be formed by a magnetron sputtering method or a sol-gel method. The material forming the second electrode may include a transparent conductive material, such as Indium Tin Oxide (ITO), indium Zinc Oxide (IZO), or the like. Specifically, the temperature at which the second electrode is formed is lower than the softening point temperature of the glass substrate.

In some embodiments of the present application, referring to fig. 7, after forming the first electrode, before forming the piezoelectric film, the method further includes:

s5000 formation of seed layer

In this step, a seed layer is formed on the side of the first electrode remote from the substrate. In particular, the material forming the seed layer may include PbTiO ₃ 、PbZrO ₃ The seed layer can thereby reduce the mismatch between the crystal lattice of the piezoelectric film (e.g., PZT piezoelectric film) and the crystal lattice of the first electrode (e.g., ITO), reduce the mismatch in thermal expansion coefficient due to local temperature, and further improve the piezoelectric performance and the usability of the fabricated piezoelectric device.

In a fifth aspect of the present disclosure, the present disclosure proposes a display device that includes the piezoelectric device described above, and thus, the display device has all the features and advantages of the piezoelectric device described above, which are not described herein. In the display device, the piezoelectric device can be used in a touch pad to realize the detection function of the pressing force and the driving function of the tactile feedback.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present disclosure, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.

In the present disclosure, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; the device can be mechanically connected, electrically connected and communicated; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the terms in this disclosure will be understood by those of ordinary skill in the art as the case may be.

In this disclosure, unless expressly stated or limited otherwise, a first feature being "above" or "below" a second feature may include both the first and second features being in direct contact, as well as the first and second features not being in direct contact but being in contact with each other by way of additional features therebetween. Moreover, a first feature being "above," "over" and "on" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is higher in level than the second feature. The first feature being "under", "below" and "beneath" the second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is less level than the second feature.

The above disclosure provides many different embodiments or examples for implementing different structures of the disclosure. The components and arrangements of specific examples are described above in order to simplify the present disclosure. Of course, they are merely examples and are not intended to limit the present disclosure. Furthermore, the present disclosure may repeat reference numerals and/or letters in the various examples, which are for the purpose of brevity and clarity, and which do not themselves indicate the relationship between the various embodiments and/or arrangements discussed.

The above is merely a specific embodiment of the disclosure, but the protection scope of the disclosure is not limited thereto, and any person skilled in the art can easily think of various changes or substitutions within the technical scope of the disclosure, which should be covered in the protection scope of the disclosure. Therefore, the protection scope of the present disclosure shall be subject to the protection scope of the claims.

Claims (14)

1. A method of preparing a piezoelectric film, comprising:

mixing piezoelectric material particles with a carrier gas to form an aerosol;

spraying the aerosol on a substrate to form a prefabricated layer;

heating the prefabricated layer to form the piezoelectric film, wherein,

the particle size of the piezoelectric material particles is 0.2-1 mu m;

the temperature of the heating treatment is not higher than 500 ℃.

2. The method of claim 1, wherein the material forming the piezoelectric material particles comprises lead zirconate titanate.

3. The method of claim 2, wherein the forming an aerosol further comprises:

mixing the piezoelectric material particles, additives, and the carrier gas;

the material forming the additive comprises lead oxide, and the content of the additive in the aerosol is 5mol at% to 15mol at%.

4. The method as recited in claim 1, further comprising:

placing the piezoelectric material particles into a first vibrating cavity to suspend the piezoelectric material particles;

introducing the carrier gas into the first cavity, and mixing the piezoelectric material particles with the carrier gas to form the aerosol;

the aerosol is sprayed into a second cavity communicated with the first cavity and deposited on the substrate in the second cavity to form the prefabricated layer.

5. The method of claim 4, wherein there is a pressure differential between the first chamber and the second chamber, the pressure in the second chamber being 500-2000 times the pressure in the first chamber.

6. The method according to claim 4, wherein the spraying is achieved by means of a nozzle, the opening diameter of which is 0.5-1mm.

7. The method of claim 4, wherein the substrate is configured to move in at least one of a first direction and a second direction, the substrate moving at a rate of 2-10mm/sec in the first and second directions, respectively, independently;

the first direction and the second direction are perpendicular to each other.

8. The method of claim 7, wherein the rate of movement is controlled such that the aerosol is deposited on the substrate at a deposition rate of 5-50 μm/min.

9. A piezoelectric film prepared by the method of any one of claims 1-8.

10. The piezoelectric film according to claim 9, wherein the thickness of the piezoelectric film is 500nm to 1mm.

11. A piezoelectric device, comprising:

a substrate;

a first electrode disposed at one side of the substrate;

a piezoelectric film provided on a side of the first electrode remote from the substrate, the piezoelectric film being as claimed in any one of claims 1 to 10;

and the second electrode is arranged on one side of the piezoelectric film away from the first electrode.

12. The piezoelectric device of claim 11, wherein at least one of the following conditions is satisfied:

the material forming the substrate comprises glass;

the material forming at least one of the first electrode and the second electrode comprises a transparent conductive material;

the thickness of the first electrode and the second electrode is 200-600nm.

13. The piezoelectric device of claim 11, further comprising a seed layer disposed between the first electrode and the piezoelectric film, the seed layer satisfying at least one of:

the material forming the seed layer comprises PbTiO ₃ 、PbZrO ₃ At least one of (2);

the thickness of the seed layer is 5nm-20nm.

14. A display device comprising the piezoelectric device according to any one of claims 11 to 13.