A flexible piezoelectric-optoelectric composite energy harvester and a manufacturing method thereof

Abstract

The present application relates to the technical field of energy collection, and discloses a flexible composite energy collector based on piezoelectric and photovoltaic and a manufacturing method thereof. The flexible energy collector comprises a conductive substrate, a piezoelectric module and a photovoltaic module arranged on the conductive substrate respectively. The piezoelectric module comprises a zinc oxide nanorod array and a first metal electrode arranged in sequence from bottom to top. The photovoltaic module comprises a zinc oxide nanorod array, a cuprous oxide film and a second metal electrode arranged in sequence from bottom to top. When the zinc oxide nanorod array is in the piezoelectric module, it functions as a piezoelectric film. When the zinc oxide nanorod array is in the photovoltaic module, it functions as an N-type semiconductor. The flexible energy collector can convert mechanical energy and / or solar energy into electrical energy when subjected to vibration, pressure or light respectively or subjected to vibration, pressure and light simultaneously. The flexible energy collector solves the environmental constraint problem of traditional single power generation form and realizes the complementary advantages of two power generation methods. The flexible energy collector is suitable for multi-scene application, has self-adjusting working mode, can significantly improve the collection capacity of the energy collector and can be used in human wearable devices.

Description

Technical Field

[0001] This invention relates to the field of energy harvesting technology, specifically to a flexible composite energy harvester based on piezoelectric photoelectric technology and its manufacturing method. Background Technology

[0002] With the development of the times, the trend towards cleaner and more efficient energy has gradually gained attention. Simultaneously, with the continuous development of microelectronics technology, various low-power micro-devices have been widely used, making energy supply for these devices a major research issue. However, using traditional chemical batteries for power supply is problematic due to their limited lifespan, requiring regular battery replacements and frequently causing environmental pollution. Currently, there are still many challenges in converting other forms of energy into electrical energy.

[0003] (1) If mechanical energy is converted into electrical energy for power supply, people usually use energy harvesting devices with single characteristics such as piezoelectric effect. However, energy harvesting devices with single characteristics are subject to different constraints and limitations. For example, energy harvesters based on piezoelectric effect only have a high output when the resonant frequency is reached, and there will be no output when there is no vibration.

[0004] (2) If solar energy is converted into electrical energy, people usually use energy harvesting devices with single characteristics such as photovoltaic effect. However, this is subject to constraints and limitations. For example, the output of energy harvesters based on photovoltaic effect is only high when there is sunlight, and it is greatly affected by the weather.

[0005] In addition, most current energy harvesters use rigid materials as their substrates, which have poor biocompatibility and are not easily applied to wearable devices. Therefore, designing a composite energy harvester that can be used in an environment that is not restricted, is easy to wear, and can better contact the skin, while simultaneously or separately harvesting vibration energy and solar energy, remains an urgent problem to be solved. Summary of the Invention

[0006] This invention discloses a flexible composite energy harvester based on piezoelectric photoelectric and its manufacturing method, which solves the environmental constraints of traditional single power generation methods. It can generate electricity by converting external mechanical energy into electrical energy and solar energy into electrical energy, either alone or simultaneously, thus solving the problem of long-term power supply for micro-devices.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A flexible composite energy harvester based on piezoelectric photoelectric technology includes: a conductive substrate and a piezoelectric module and a photoelectric module respectively disposed on the conductive substrate;

[0009] The piezoelectric module includes an array of zinc oxide nanorods arranged sequentially from bottom to top and a first metal electrode;

[0010] The optoelectronic module includes the zinc oxide nanorod array, the cuprous oxide thin film, and the second metal electrode arranged sequentially from bottom to top.

[0011] When the zinc oxide nanorod array is in the piezoelectric module, it functions as a piezoelectric thin film.

[0012] When the zinc oxide nanorod array is in the optoelectronic module, it functions as an N-type semiconductor.

[0013] Optionally, there is a certain distance between the first metal electrode and the cuprous oxide thin film.

[0014] Optionally, the conductive substrate is made of PET-ITO.

[0015] Optionally, the first metal electrode and the second metal electrode are made of aluminum.

[0016] Optionally, wires for testing performance are also provided at the conductive substrate, the first metal electrode, and the second metal electrode.

[0017] A method for fabricating a flexible composite energy harvester based on piezoelectric photoelectric technology includes the following steps:

[0018] A zinc oxide seed layer was sputtered onto the conductive substrate by magnetron sputtering.

[0019] A mixed solution of zinc acetate and hexamethylenetetramine was prepared and mixed in a 1:1 ratio. The zinc oxide nanorod array was then grown on the conductive substrate with the zinc oxide seed layer grown thereon using a hydrothermal method.

[0020] The cuprous oxide film is sputtered onto one side surface of the zinc oxide nanorod array by magnetron sputtering.

[0021] The first metal electrode is deposited on the zinc oxide nanorod array at a certain distance from the cuprous oxide film by vacuum evaporation, and the second metal electrode is deposited on the cuprous oxide film. The wire is led out from the conductive substrate, the first metal electrode, and the second metal electrode.

[0022] Optionally, the process also includes preparing the conductive substrate, the preparation including:

[0023] The samples were ultrasonically cleaned with acetone, anhydrous ethanol, and deionized water, respectively, and then dried in a drying oven.

[0024] Optionally, it also includes a packaging method after fabrication, the packaging method comprising:

[0025] Prepare a PDMS solution and encapsulate it by spin coating the PDMS solution onto the fabricated device.

[0026] The beneficial effects of this invention are:

[0027] (1) The flexible energy harvester in this application includes piezoelectric and photoelectric coupling methods, which realize the complementary advantages of the two power generation methods. The two methods can generate electricity individually or simultaneously. It has an autonomous adjustment working mode, which can significantly improve the harvesting capability of the energy harvester. It has a high output electrical signal and also solves the problem of sustainable power supply for micro devices by the composite energy harvester.

[0028] (2) This application solves the environmental constraints of traditional single power generation methods and can meet the conditions for data collection in both sunny and vibrating or stressed environments, making it suitable for multi-scenario applications;

[0029] (3) This application solves the problem that general energy harvesters are not suitable for wearable devices. The conductive substrate is a transparent and flexible conductive substrate, which makes the bottom of the device soft and fits the skin well.

[0030] (4) The structure of this application is simple, unlike the mechanical stacking of traditional composite energy harvesters. Zinc oxide nanorod arrays are used in both the piezoelectric module and the photoelectric module, and the zinc oxide nanorod arrays play different roles in different modules, which solves the problem of complex structure of existing composite energy harvesters.

[0031] (5) The method of manufacturing the composite energy harvester in this application is easy and miniaturized, which solves the problems of complex manufacturing and large size of traditional composite energy harvesters. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the structure of a flexible energy harvester provided in an embodiment of the present invention;

[0033] Figure 2A This is a schematic diagram illustrating the electrical signal generated by the flexible energy harvester when it is subjected to pressure, as provided in an embodiment of the present invention.

[0034] Figure 2B This is a schematic diagram illustrating the electrical signals generated by the flexible energy harvester when it undergoes bending deformation due to vibration, as provided in an embodiment of the present invention.

[0035] Figure 3 This is a schematic diagram showing the electrical signal generated by the flexible energy harvester when it is exposed to light, as provided in an embodiment of the present invention.

[0036] Figure 4A A schematic diagram illustrating the electrical signals generated by the flexible energy harvester when it is simultaneously subjected to pressure and light, as provided in an embodiment of the present invention.

[0037] Figure 4B This is a schematic diagram illustrating the electrical signals generated by the flexible energy harvester when it is simultaneously subjected to vibration and bending deformation, as well as illumination, according to an embodiment of the present invention.

[0038] Figure 5 A flowchart illustrating the manufacturing method of a flexible energy harvester provided in an embodiment of the present invention.

[0039] Figure label:

[0040] 1-Conductive substrate; 2-Zinc oxide nanorod array; 3-First metal electrode; 4-Cuprous oxide thin film;

[0041] 5-Second metal electrode. Detailed Implementation

[0042] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] This application proposes a flexible composite energy harvester based on piezoelectric photoelectric technology, such as... Figure 1 As shown, the device includes a conductive substrate 1 and a piezoelectric module and a photoelectric module respectively disposed on the conductive substrate. When the flexible energy harvester is exposed to light, the photoelectric module activates, converting solar energy into electrical energy. When the flexible energy harvester is subjected to vibration or pressure, the piezoelectric module activates, converting mechanical energy into electrical energy. When the flexible energy harvester is simultaneously exposed to light and vibration or pressure, the piezoelectric module and the photoelectric module activate simultaneously, converting both solar and mechanical energy into electrical energy. This allows optical and mechanical signals to be converted individually or simultaneously into electrical signals, which is not constrained by the environment and increases the output of the electrical signal of the flexible energy harvester, thereby improving its energy harvesting capability.

[0044] Specifically, the piezoelectric module includes a zinc oxide nanorod array 2 and a first metal electrode 3 arranged sequentially from bottom to top. The first metal electrode 3 is made of aluminum. When the flexible energy harvester is subjected to external vibration or pressure and undergoes bending or other deformations, as shown in Figure 2, the zinc oxide nanorod array 2, which serves as a piezoelectric film, deforms under the action of external force. Due to its positive piezoelectric effect, polarization occurs inside, and opposite charges are formed on its surface. When the direction of the external force changes, the polarity of its surface charge also changes, thereby enabling the flexible energy harvester to generate an alternating current signal between the conductive substrate 1 and the first metal electrode 3, realizing the energy harvesting by converting the mechanical signal into an electrical signal.

[0045] The optoelectronic module includes, from bottom to top, a zinc oxide nanorod array 2, a cuprous oxide thin film 4, and a second metal electrode 5. When the flexible energy harvester is exposed to light, such as Figure 3 As shown, the optoelectronic module performs energy harvesting. The zinc oxide nanorod array 2, which is an N-type semiconductor, and the cuprous oxide thin film 4, which is a P-type semiconductor, form a PN junction. When the PN junction is illuminated, new hole-electron pairs are formed due to the photovoltaic effect. Under the action of the electric field of the PN junction, holes flow from the N pole to the P pole, and electrons flow from the P pole to the N pole. Therefore, the principle of the device under illumination is to generate a DC signal between the conductive substrate 1 and the second metal electrode 5, realizing the energy harvesting of the conversion from optical signal to electrical signal.

[0046] When the flexible energy harvester is subjected to vibration or pressure and light simultaneously, as shown in Figure 4, the piezoelectric module and the photoelectric module work together to realize the energy harvesting by converting mechanical signals and optical signals into electrical signals.

[0047] It should be noted that the zinc oxide nanorod array 2 in the piezoelectric module and the zinc oxide nanorod array 2 in the optoelectronic module are the same zinc oxide nanorod array, but they play different roles during the operation of different modules. For example, when the piezoelectric module is working, the zinc oxide nanorod array 2 acts as a piezoelectric thin film; when the optoelectronic module is working, it acts as an N-type semiconductor; when both the piezoelectric and optoelectronic modules are working simultaneously, the zinc oxide nanorod array 2 acts as both a piezoelectric thin film and an N-type semiconductor. It should also be noted that there should be a certain distance between the first metal electrode 3 and the cuprous oxide thin film 4 of the piezoelectric module. Furthermore, to facilitate performance testing, conductive wires for performance testing are provided at the conductive substrate 1, the first metal electrode 3, and the second metal electrode 5.

[0048] Specifically, the conductive substrate 1 is made of PET-ITO, a transparent flexible conductive substrate, which enables the flexible energy harvester to adhere well to the skin, making it more suitable for wearable devices. Specifically, in this application, the thickness of the conductive substrate 1 ranges from 100 to 175 μm, the thickness of the zinc oxide nanorod array 2 ranges from 1 to 4 μm, the thickness of the cuprous oxide thin film 4 ranges from 0.4 to 1 μm, the thickness of the first metal electrode 3 and the second metal electrode 5 ranges from 0.8 to 1 μm, and the overall planar dimensions of the energy harvester are 2 cm * 1 cm.

[0049] Furthermore, this application also proposes a method for fabricating a flexible composite energy harvester based on piezoelectric photoelectric technology, such as... Figure 5 As shown, the method includes the following steps:

[0050] S1: A zinc oxide seed layer is sputtered onto the conductive substrate 1 by magnetron sputtering;

[0051] S2: Prepare 0.04 mol / L zinc acetate and 0.04 mol / L hexamethylenetetramine respectively, mix them in a 1:1 ratio, and grow zinc oxide nanorod array 2 on conductive substrate 1 with zinc oxide seed crystal layer by hydrothermal method;

[0052] S3: A cuprous oxide thin film 4 is sputtered on one side surface of the zinc oxide nanorod array 2 by magnetron sputtering.

[0053] S4: A first metal electrode 3 is deposited on the other side of the zinc oxide nanorod array 2 by vacuum evaporation, a second metal electrode 5 is deposited on the cuprous oxide thin film 4, and wires are led out from the conductive substrate 1, the first metal electrode 3 and the second metal electrode 5.

[0054] In step S1, the magnetron sputtering method for fabricating the zinc oxide seed layer requires an oxygen-argon ratio of 7.5:20, a sputtering power of 120W, a working pressure of 1Pa, and a sputtering time of 90 minutes. In step S2, the growth time for the zinc oxide nanorod array 2 is specified as 9 hours, the growth temperature as 80℃, and the concentration of the mixed solution as 0.04 mol / L. It should be noted that after the reaction, the zinc oxide nanorod array 2 must be repeatedly rinsed with deionized water and dried for later use. In step S3, the sputtering method for the cuprous oxide thin film 4 requires an oxygen-argon ratio of 1:20, a sputtering power of 60W, a working pressure of 1Pa, and a sputtering time of 20 minutes.

[0055] In addition, the preparation of the conductive substrate includes ultrasonic cleaning with acetone, anhydrous ethanol, and deionized water for a specified time, followed by drying in a drying oven. The conductive substrate 1 can be cut to a size corresponding to the planar dimensions of the flexible energy harvester. For example, in this embodiment, the conductive substrate 1 has dimensions of 2cm x 1cm, and the cleaning time is 10 minutes.

[0056] In addition, the method includes a post-fabrication encapsulation method, which involves preparing a PDMS (Polydimethylsiloxane) solution and spin-coating it onto the fabricated device. Specifically, the PDMS solution is prepared by mixing PDMS prepolymer A (e.g., vinyl polydimethylsiloxane) and crosslinking agent B (e.g., polydimethylhydrosiloxane) at a ratio of 10:1. After preparation, the solution is applied to the surface at a speed of 500 rpm for 30 seconds, thus completing the encapsulation process.

[0057] It is obvious that those skilled in the art can make various modifications and variations to the embodiments of the present invention without departing from the spirit and scope of the invention. Therefore, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention also intends to include these modifications and variations.

Claims

1. A flexible composite energy harvester based on piezoelectric photoelectric technology, characterized in that, include: A conductive substrate and a piezoelectric module and a photoelectric module respectively disposed on the conductive substrate; The piezoelectric module includes an array of zinc oxide nanorods arranged sequentially from bottom to top and a first metal electrode; The optoelectronic module includes the zinc oxide nanorod array, the cuprous oxide thin film, and the second metal electrode arranged sequentially from bottom to top, and there is a certain distance between the first metal electrode and the cuprous oxide thin film; When the zinc oxide nanorod array is in the piezoelectric module, it functions as a piezoelectric thin film. When the zinc oxide nanorod array is in the optoelectronic module, it functions as an N-type semiconductor.

2. The flexible composite energy harvester based on piezoelectric photoelectric technology according to claim 1, characterized in that, The conductive substrate is made of PET-ITO.

3. The flexible composite energy harvester based on piezoelectric photoelectric technology according to claim 1, characterized in that, The first metal electrode and the second metal electrode are made of aluminum.

4. The flexible composite energy harvester based on piezoelectric photoelectric technology according to claim 1, characterized in that, Conductors for testing performance are also provided at the conductive substrate, the first metal electrode, and the second metal electrode.

5. A method for fabricating a flexible composite energy harvester based on piezoelectric photoelectric technology as described in any one of claims 1-4, characterized in that, Includes the following steps: A zinc oxide seed layer was sputtered onto the conductive substrate by magnetron sputtering. A mixed solution of zinc acetate and hexamethylenetetramine was prepared and mixed in a 1:1 ratio. The zinc oxide nanorod array was then grown on the conductive substrate with the zinc oxide seed layer using a hydrothermal method. The cuprous oxide film is sputtered onto one side surface of the zinc oxide nanorod array by magnetron sputtering. The first metal electrode is deposited on the zinc oxide nanorod array at a certain distance from the cuprous oxide film by vacuum evaporation, and the second metal electrode is deposited on the cuprous oxide film. Wires are led out from the conductive substrate, the first metal electrode, and the second metal electrode.

6. The manufacturing method according to claim 5, characterized in that, It also includes preparation work for the conductive substrate, the preparation work including: The samples were ultrasonically cleaned with acetone, anhydrous ethanol, and deionized water, respectively, and then dried in a drying oven.

7. The manufacturing method according to claim 5, characterized in that, It also includes a packaging method after fabrication, the packaging method comprising: Prepare a PDMS solution and encapsulate it by spin coating the PDMS solution onto the fabricated device.

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