A flexible pressure sensor
By designing a flexible pressure sensor combining organic and inorganic piezoelectric materials and preparing concave and convex structures at the thin film interface, the problem of insufficient output voltage and sensitivity to slight deformation in the prior art is solved, and more efficient energy conversion and more sensitive pressure response are achieved.
Patent Information
- Application Number
- CN202411664308.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-20
- Publication Date
- 2025-04-04
AI Technical Summary
Existing nanogenerator-based pressure sensors have limitations in output voltage and sensitivity to slight deformation.
A flexible pressure sensor is designed, a first flexible piezoelectric film and a second flexible piezoelectric film made of homemade polydimethylsiloxane (PDMS) or silicone grease and resin polymer solution mixed with piezoelectric powder, combining organic and inorganic piezoelectric materials, and a concave and convex structure is prepared at the film interface to enhance pressure response.
By combining two different piezoelectric materials and introducing friction mechanisms, the energy conversion efficiency is improved; the piezoelectric material selection range is expanded through organic/inorganic combination method; and by introducing micro-nano structures at the interface, the response to slight deformation is enhanced.
Smart Images
Figure CN119756637A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of pressure sensors, and in particular relates to a flexible pressure sensor. Background Art
[0002] Traditional nanogenerator pressure sensors are mainly based on friction, piezoelectric or friction + piezoelectric principles. These sensors have limitations in energy conversion efficiency and material selection range. As a new energy technology, nanogenerators (NG) have been used to develop self-powered pressure sensors. These sensors can convert mechanical energy into electrical energy to achieve real-time monitoring of pressure signals. However, existing pressure sensors based on nanogenerators have certain limitations in output voltage and sensitivity to small deformations. At the same time, pressure sensors based on nanogenerators have shortcomings in output voltage. Summary of the invention
[0003] To achieve the above object, the technical solution of the present invention is as follows: a flexible pressure sensor, the pressure sensor comprising a metal bottom electrode, a flexible piezoelectric film group and a metal top electrode, wherein: A metal bottom electrode for providing stable electrical contact and support; The first flexible piezoelectric film is connected to the metal bottom electrode and is made of self-made polydimethylsiloxane (PDMS) or silicone grease, resin polymer solution mixed with piezoelectric powder and then cured, and has a designable piezoelectric response characteristic. Preferably, when the thickness is in the range of 10 μm-2 mm, the performance is better; The second flexible piezoelectric film is located on the first flexible piezoelectric film. A polymer film different from the first flexible piezoelectric film can be used to have intrinsic piezoelectric properties, or piezoelectric powder can be mixed into a non-piezoelectric material. A layer of inorganic piezoelectric material can also be coated on the first flexible piezoelectric film to enhance the piezoelectric effect. A metal top electrode, covering the second flexible piezoelectric film and connected to the second flexible piezoelectric film, for collecting and transmitting piezoelectric signals; Preferably, a concave-convex nano-micro structure is provided between the first flexible piezoelectric film and the second flexible piezoelectric film to enhance pressure response.
[0004] Based on the above technical features, the film is made of homemade PDMS solution mixed with piezoelectric powder, and the piezoelectric response of the film can be independently designed to meet different application requirements.
[0005] As an improvement of the invention, the concave-convex structure between the first flexible piezoelectric film and the second flexible piezoelectric film is prepared by a thin film deposition micro-nano processing step.
[0006] Based on the above technical features, a concave-convex structure is prepared at the interface of the first flexible piezoelectric film and the second flexible piezoelectric film by thin film deposition micro-nano processing and other methods to enhance the response of the sensor to tiny deformations.
[0007] As an improvement of the invention, the second flexible piezoelectric film is made of PVDF organic piezoelectric material.
[0008] Based on the above technical features, organic piezoelectric materials, such as PVDF, can be used.
[0009] As an improvement of the invention, a layer of PZT, BTO or PMNPT inorganic piezoelectric material is coated on the first flexible piezoelectric film.
[0010] Based on the above technical features, a layer of inorganic piezoelectric material, such as PZT, BTO, PMNPT, etc., may also be coated on the first flexible piezoelectric film to improve the performance of the sensor.
[0011] As an improvement of the invention, the steps of preparing the homemade PDMS solution include: The PDMS prepolymer, the cross-linking agent and the organic solvent are mixed to prepare a PDMS solution, wherein the mass ratio of the PDMS prepolymer to the cross-linking agent is 15:1 to 5:1, and the mass ratio of the PDMS prepolymer to the organic solvent is 1:2 to 1:10.
[0012] As an improvement of the invention, the steps of preparing the first flexible piezoelectric film include: The homemade PDMS solution was mixed with piezoelectric powder in a specific ratio to form a uniform mixture; forming the mixture into a thin film by spin coating, spray coating or other thin film preparation techniques; The ratio of PDMS solution to piezoelectric powder, as well as the thickness and shape of the film are adjusted according to the desired piezoelectric response characteristics.
[0013] Based on the above technical features, the shape of the film can be achieved by adjusting the rotation speed of the substrate and the viscosity of the coating during spin coating; the preparation of the film also includes using a rotating fixture or a planetary rotating fixture to improve the uniformity of the film thickness.
[0014] As an improvement of the invention, the piezoelectric powder is selected from barium titanate, potassium sodium niobate or lead zirconate titanate nanoparticles, the ratio of the homemade PDMS solution to the piezoelectric powder is 1:1 to 1:10, the thickness of the first flexible piezoelectric film is 10 to 100 μm, and the film thickness is controlled by adjusting the rotation speed and coating viscosity during spin coating.
[0015] As an improvement of the invention, the preparation steps of the second flexible piezoelectric film include: Select suitable organic piezoelectric materials, or select suitable inorganic piezoelectric materials; If an inorganic piezoelectric material is used, a uniform piezoelectric material layer is formed on the first flexible piezoelectric film by physical vapor deposition, chemical vapor deposition or other coating techniques; The thickness of the film is adjusted to optimize the piezoelectric performance and the overall sensitivity of the sensor.
[0016] Based on the above technical features, the shape of the film can be achieved by adjusting the rotation speed of the substrate and the viscosity of the coating during spin coating, or by inducing a self-assembled microstructure on the surface of the double-layer film through mechanical manipulation or heat treatment; the film has good piezoelectric response characteristics and adjustability, as well as optimized sensor sensitivity.
[0017] As an improvement of the invention, the organic piezoelectric material is PVDF and its copolymers poly(vinylidene fluoride-trifluoroethylene) and poly(vinylidene fluoride-hexafluoropropylene), the physical vapor deposition technology includes vacuum evaporation, wherein the evaporation method includes resistance heating, high-frequency induction heating, electron beam, laser beam, ion beam high-energy bombardment of the plating material, and the thickness adjustment of the film is achieved by controlling the deposition rate and time to obtain a film thickness of 10 to 100 μm.
[0018] As an improvement of the invention, the steps of preparing the concave-convex structure between the first flexible piezoelectric film and the second flexible piezoelectric film include: Using nanoimprinting or optical exposure to define the surface pattern, combined with plasma etching technology, to prepare a micrometer or nanometer-scale concave-convex structure on the interface between the first flexible piezoelectric film and the second flexible piezoelectric film; Alternatively: a thin film deposition technique is used to deposit and grow a piezoelectric film on the interface between the first flexible piezoelectric film and the second flexible piezoelectric film, and an uneven island-shaped microstructure is prepared by a rapid thermal annealing process.
[0019] By precisely controlling the size and distribution of the concave and convex structures, the response speed and sensitivity of the sensor to pressure changes can be optimized.
[0020] Compared with the prior art, the beneficial effects of the present invention are: 1) Different from the traditional nanogenerator which is based on friction or piezoelectricity or friction plus piezoelectricity, the present invention combines two different piezoelectric materials, introduces two piezoelectric mechanisms and one friction mechanism, and has higher energy conversion efficiency; 2) Different from the traditional design based on stacking two flexible organic materials, the present invention proposes an organic / inorganic combination method, which expands the selection range of piezoelectric materials; 3) Different from the traditional optimization scheme of directly engraving the concave-convex structure on the interface, the present invention introduces additional micro-nano structure on the interface to reduce the damage to the material surface. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 Schematic diagram of the overall structure of the pressure sensor in this embodiment; Figure 2 This is a flow chart for preparing the homemade PDMS solution in this embodiment; Figure 3 This is a flow chart for preparing the first flexible piezoelectric film in this embodiment; Figure 4 This is a flow chart for preparing the second flexible piezoelectric film in this embodiment.
[0022] List of figure symbols: 100 - metal bottom electrode, 101 - metal top electrode, 102 - first flexible piezoelectric film, 103 - second flexible piezoelectric film, 104 - concave-convex structure. DETAILED DESCRIPTION
[0023] The present invention will be further explained below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.
[0024] Example: Figure 1 As shown, this embodiment provides a flexible pressure sensor, the pressure sensor comprising a metal bottom electrode 100, a flexible piezoelectric film group and a metal top electrode 101, wherein: A metal bottom electrode 100 for providing stable electrical contact and support; The first flexible piezoelectric film 102 is connected to the metal bottom electrode 100 and is made of self-made polydimethylsiloxane (PDMS) or silicone grease, resin polymer solution mixed with piezoelectric powder and then cured, and has a designable piezoelectric response characteristic. Preferably, when the thickness is in the range of 10 μm-2 mm, the performance is better.
[0025] The second flexible piezoelectric film 103 is located on the first flexible piezoelectric film 102, or a layer of inorganic piezoelectric material is coated on the first flexible piezoelectric film 102 to enhance the piezoelectric effect; A metal top electrode 101, covering the second flexible piezoelectric film 103, connected to the second flexible piezoelectric film 103, and used for collecting and transmitting piezoelectric signals; A concave-convex nano-micro structure is disposed between the first flexible piezoelectric film 102 and the second flexible piezoelectric film 103 .
[0026] Made of homemade PDMS solution mixed with piezoelectric powder, the piezoelectric response of the film can be independently designed to suit different application requirements.
[0027] Furthermore, the concavo-convex structure 104 between the first flexible piezoelectric film 102 and the second flexible piezoelectric film 103 is manufactured by a thin film deposition micro-nano processing step.
[0028] A concave-convex structure 104 is prepared at the interface of the first flexible piezoelectric film 102 and the second flexible piezoelectric film 103 by thin film deposition micro-nano processing and other methods to enhance the response of the sensor to slight deformation.
[0029] Furthermore, the second flexible piezoelectric film 103 is made of PVDF organic piezoelectric material.
[0030] Organic piezoelectric materials such as PVDF can be used.
[0031] Furthermore, a layer of PZT, BTO or PMNPT inorganic piezoelectric material is deposited on the first flexible piezoelectric film 102 .
[0032] A layer of inorganic piezoelectric material, such as PZT, BTO, PMNPT, etc., may also be coated on the first flexible piezoelectric film 102 to improve the performance of the sensor.
[0033] Furthermore, if Figure 2 As shown, the preparation steps of the homemade PDMS solution include: The PDMS prepolymer, the cross-linking agent and the organic solvent are mixed to prepare a PDMS solution, wherein the mass ratio of the PDMS prepolymer to the cross-linking agent is 15:1 to 5:1, and the mass ratio of the PDMS prepolymer to the organic solvent is 1:2 to 1:10.
[0034] Furthermore, if Figure 3 As shown, the preparation steps of the first flexible piezoelectric film 102 include: The homemade PDMS solution was mixed with piezoelectric powder in a specific ratio to form a uniform mixture; forming the mixture into a thin film by spin coating, spray coating or other thin film preparation techniques; The ratio of PDMS solution to piezoelectric powder, as well as the thickness and shape of the film are adjusted according to the desired piezoelectric response characteristics.
[0035] The shape of the film can be achieved by adjusting the rotation speed of the substrate and the viscosity of the coating during spin coating; the preparation of the film also includes using a rotating fixture or a planetary rotating fixture to improve the uniformity of the film thickness.
[0036] Furthermore, the piezoelectric powder is selected from barium titanate, potassium sodium niobate or lead zirconate titanate nanoparticles, the ratio of the homemade PDMS solution to the piezoelectric powder is 1:1 to 1:10, the thickness of the first flexible piezoelectric film 102 is 10 to 100 μm, and the film thickness is controlled by adjusting the rotation speed and coating viscosity during spin coating.
[0037] Furthermore, if Figure 4 As shown, the preparation steps of the second flexible piezoelectric film 103 include: Select suitable organic piezoelectric materials, or select suitable inorganic piezoelectric materials; If an inorganic piezoelectric material is used, a uniform piezoelectric material layer is formed on the first flexible piezoelectric film 102 by physical vapor deposition, chemical vapor deposition or other coating techniques; The thickness of the film is adjusted to optimize the piezoelectric performance and the overall sensitivity of the sensor.
[0038] The shape of the film can be achieved by adjusting the rotation speed of the substrate and the viscosity of the coating during spin coating, or by inducing a self-assembled microstructure on the surface of the double-layer film through mechanical manipulation or heat treatment; the film has good piezoelectric response characteristics and adjustability, as well as optimized sensor sensitivity.
[0039] Furthermore, the organic piezoelectric material is PVDF and its copolymers poly(vinylidene fluoride-trifluoroethylene) and poly(vinylidene fluoride-hexafluoropropylene), the physical vapor deposition technology includes vacuum evaporation, wherein the evaporation method includes resistance heating, high-frequency induction heating, electron beam, laser beam, ion beam high-energy bombardment of the plating material, and the thickness adjustment of the film is achieved by controlling the deposition rate and time to obtain a film thickness of 10 to 100 μm.
[0040] Furthermore, the steps of preparing the concavo-convex structure 104 between the first flexible piezoelectric film 102 and the second flexible piezoelectric film 103 include: A nanoimprint or optical exposure method is used to define the surface pattern, and a concave-convex structure 104 at a micrometer or nanometer level is prepared on the interface between the first flexible piezoelectric film 102 and the second flexible piezoelectric film 103 in combination with a plasma etching technique; Alternatively, a thin film deposition technique is used to deposit and grow a piezoelectric film on the interface between the first flexible piezoelectric film 102 and the second flexible piezoelectric film 103, and a rough island-shaped microstructure is prepared by a rapid thermal annealing process.
[0041] By precisely controlling the size and distribution of the concave-convex structure 104 , the response speed and sensitivity of the sensor to pressure changes are optimized.
[0042] It should be noted that the above content only illustrates the technical idea of the present invention and cannot be used to limit the protection scope of the present invention. For ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications all fall within the protection scope of the claims of the present invention.
Claims
1. A flexible pressure sensor, characterized in that: The pressure sensor comprises a metal bottom electrode (100), a flexible piezoelectric film group and a metal top electrode (101), wherein: A metal bottom electrode (100) for providing stable electrical contact and support; The first flexible piezoelectric film (102) is connected to the metal bottom electrode (100), is made of a self-made polydimethylsiloxane or silicone grease, a resin polymer solution mixed with piezoelectric powder and then solidified, and has a designable piezoelectric response characteristic; A second flexible piezoelectric film (103) is located on the first flexible piezoelectric film (102), or a layer of inorganic piezoelectric material is coated on the first flexible piezoelectric film (102) to enhance the piezoelectric effect; A metal top electrode (101), covering the second flexible piezoelectric film (103), connected to the second flexible piezoelectric film (103), and used for collecting and transmitting piezoelectric signals; A concave-convex structure (104) is provided between the first flexible piezoelectric film (102) and the second flexible piezoelectric film (103).
2. A flexible pressure sensor according to claim 1, characterized in that: The concave-convex structure (104) between the first flexible piezoelectric film (102) and the second flexible piezoelectric film (103) is prepared by a thin film deposition micro-nano processing step.
3. The flexible pressure sensor according to claim 1, characterized in that: The second flexible piezoelectric film (103) is made of PVDF organic piezoelectric material.
4. The flexible pressure sensor according to claim 1, characterized in that: A layer of PZT, BTO or PMNPT inorganic piezoelectric material is coated on the first flexible piezoelectric film (102).
5. The flexible pressure sensor according to claim 1, characterized in that: The preparation steps of the homemade PDMS solution include: The PDMS prepolymer, the cross-linking agent and the organic solvent are mixed to prepare a PDMS solution, wherein the mass ratio of the PDMS prepolymer to the cross-linking agent is 15:1 to 5:1, and the mass ratio of the PDMS prepolymer to the organic solvent is 1:2 to 1:
10.
6. The flexible pressure sensor according to claim 1, characterized in that: The steps of preparing the first flexible piezoelectric film (102) include: The homemade PDMS solution was mixed with piezoelectric powder in a specific ratio to form a uniform mixture; forming the mixture into a thin film by spin coating, spray coating or other thin film preparation techniques; The ratio of PDMS solution to piezoelectric powder, as well as the thickness and shape of the film are adjusted according to the desired piezoelectric response characteristics.
7. The flexible pressure sensor according to claim 6, characterized in that: The piezoelectric powder is selected from barium titanate, potassium sodium niobate or lead zirconate titanate nanoparticles, the ratio of the self-made PDMS solution to the piezoelectric powder is 1:1 to 1:10, the thickness of the first flexible piezoelectric film (102) is 10 to 100 μm, and the film thickness is controlled by adjusting the rotation speed and coating viscosity during spin coating.
8. The flexible pressure sensor according to claim 1, characterized in that: The preparation steps of the second flexible piezoelectric film (103) include: Select suitable organic piezoelectric materials, or select suitable inorganic piezoelectric materials; If an inorganic piezoelectric material is used, a uniform piezoelectric material layer is formed on the first flexible piezoelectric film (102) by physical vapor deposition, chemical vapor deposition or other coating techniques; The thickness of the film is adjusted to optimize the piezoelectric performance and the overall sensitivity of the sensor.
9. The flexible pressure sensor according to claim 8, characterized in that: The organic piezoelectric material is PVDF and its copolymers poly(vinylidene fluoride-trifluoroethylene) and poly(vinylidene fluoride-hexafluoropropylene), the physical vapor deposition technology includes vacuum evaporation, wherein the evaporation method includes resistance heating, high-frequency induction heating, electron beam, laser beam, ion beam high-energy bombardment of the plating material, and the thickness adjustment of the film is achieved by controlling the deposition rate and time to obtain a film thickness of 10 to 100 μm.
10. The flexible pressure sensor according to claim 1, characterized in that: The steps of preparing the concavo-convex structure (104) between the first flexible piezoelectric film (102) and the second flexible piezoelectric film (103) include: A nanoimprint or optical exposure method is used to define a surface pattern, and a plasma etching technique is used to prepare a micrometer or nanometer-level concave-convex structure (104) on the interface between the first flexible piezoelectric film (102) and the second flexible piezoelectric film (103); or a thin film deposition technique is used to deposit and grow a piezoelectric film on the interface between the first flexible piezoelectric film (102) and the second flexible piezoelectric film (103), and a concave-convex island microstructure is prepared by a rapid thermal annealing process; By precisely controlling the size and distribution of the concave-convex structure (104), the response speed and sensitivity of the sensor to pressure changes are optimized.