WO2018064893A1

WO2018064893A1 - Light enhanced vibration energy harvesting device and array

Info

Publication number: WO2018064893A1
Application number: PCT/CN2017/086546
Authority: WO
Inventors: 王凯; 伊朗麦内什艾麦德
Original assignee: 中山大学
Priority date: 2016-10-09
Filing date: 2017-05-31
Publication date: 2018-04-12
Also published as: CN106373977A; CN106373977B

Abstract

A light enhanced vibration energy harvesting device and an array are disclosed in the present disclosure, the light enhanced vibration energy harvesting device comprising a thin film transistor and a piezoelectric unit. The piezoelectric unit, as a top gate of the thin film transistor, is in contact with the top of the thin film transistor. The piezoelectric film is a transparent piezoelectric film, and the electrodes provided on the top and bottom of the piezoelectric film are all transparent conductive materials. The thin film transistor is a photosensitive thin film transistor. With respect to the related art, the light enhanced vibration energy harvesting device of the present invention harvests energy using the piezoelectric unit and rectifies using the thin film transistor so as to convert pressure into direct current for outputting, achieving the energy harvesting function and rectifying function in one device. The use of the photosensitive thin film transistor allows the device to have a light enhancement effect, namely, under the action of light, the output current is increased, improving the energy harvesting efficiency of the device.

Description

Light-enhanced vibration energy harvesting device and array

Technical field

The present invention relates to the field of energy harvesting, and more particularly to a light-enhanced vibration energy harvesting device and array.

Background technique

The emergence of wearable electronics will revolutionize the way people live. However, the power supply problem is the main bottleneck that restricts its development and widespread application. Current batteries are the primary means of powering wearable electronics. Battery life is limited and needs to be replaced or recharged on a regular basis, which not only adds cost, but is also extremely inconvenient. While people are actively developing various "throttle" technologies such as low-power (microwatt or even nanowatt) integrated circuits, there is an urgent need to find various "open source" ways (such as extracting energy from the environment) to get rid of the right Battery dependence.

Photovoltaic power generation, thermoelectric power generation, RF energy transmission and piezoelectric energy harvesting are several environmental energy harvesting technologies that are currently concentrated in research. These technologies convert light, thermal, electromagnetic, and mechanical energy into electrical energy in the environment. These technologies have their own advantages and disadvantages, such as photovoltaic technology is relatively mature and energy density is relatively large, but with time-varying and space limitations. Although the thermoelectric power generation is simple and durable, it is not easy to miniaturize and integrate. The energy transmitted by electromagnetic waves emitted by radio frequency transmitters is generally low in density and the transmission distance is very limited. Piezoelectric energy harvesting has the advantages of simple structure, high energy density, long life, no electromagnetic interference, and easy miniaturization and integration. It is receiving more and more attention and is considered to be the most promising technology to replace batteries. Therefore, in recent years, energy harvesting based on piezoelectric effect has become a research hotspot. Since the piezoelectric effect is an AC voltage signal, the rectifier circuit is usually required to perform matching to achieve DC output. Therefore, the existing piezoelectric energy harvesting technology needs to further include energy conversion, storage, and power management.

Summary of the invention

The object of the present invention is to overcome the shortcomings and deficiencies in the prior art, and to provide a light-enhanced piezoelectric gated thin film transistor by integrating a piezoelectric thin film device and a photosensitive thin film transistor to realize light enhancement of energy harvesting and rectifying functions. The vibration energy harvesting device forms an energy harvesting array based thereon.

The present invention is achieved by the following technical solution: a light-enhanced vibration energy harvesting device comprising a thin film transistor and a piezoelectric unit, which serves as a top gate of the thin film transistor in contact with the top of the thin film transistor.

Compared with the prior art, the light-enhanced vibration energy collecting device of the invention uses the piezoelectric unit to collect energy, the thin film transistor rectifies, converts the pressure into a direct current output, and realizes the energy collecting and rectifying functions.

Further, the thin film transistor includes a substrate, a bottom gate on the upper portion of the substrate, a bottom dielectric layer on the upper portion of the bottom gate, and a channel on the upper portion of the bottom dielectric layer, respectively on the source sides of the channel and Drain, and located in the channel, source And a top dielectric layer on the top of the drain.

Further, the light-enhanced vibration energy harvesting device further includes an energy storage unit and a load, and the energy storage unit and the load are respectively connected to the source of the thin film transistor.

Further, the piezoelectric unit includes a piezoelectric film and electrodes respectively disposed on the top and bottom of the piezoelectric film, and the bottom electrode of the piezoelectric unit is bonded to the top of the thin film transistor or directly prepared on the top of the thin film transistor.

Further, the bottom electrode of the piezoelectric unit and the top dielectric layer of the thin film transistor are bonded by an anisotropic conductive film or the piezoelectric unit is prepared on the top of the thin film transistor.

Further, the drain and the bottom gate of the thin film transistor are connected to the bottom electrode of the piezoelectric unit.

Further, the piezoelectric film is a transparent piezoelectric film, and electrodes respectively disposed on the top and bottom of the piezoelectric film are transparent electrodes, and the thin film transistor is a photosensitive thin film transistor. The use of a photosensitive thin film transistor enables the device to have a light enhancement effect, that is, an increase in output current under illumination, thereby improving the energy collection efficiency of the device.

Further, the thin film transistor is an amorphous silicon thin film transistor, a polycrystalline silicon thin film transistor or an organic semiconductor thin film transistor; and the piezoelectric thin film is a PVDF piezoelectric plastic film.

The present invention also provides a light-enhanced vibration energy harvesting array comprising a plurality of light-enhanced vibration energy harvesting devices, the plurality of light-enhanced vibration energy harvesting devices being arranged in an array, the adjacent vibration energy collecting The devices are connected by metal and connected to the bus. The light-enhanced vibration energy harvesting device is one of the aforementioned light-enhanced vibration energy harvesting devices.

Compared with the prior art, the light-enhanced vibration energy harvesting array of the present invention collects energy through the piezoelectric unit in the device, and the thin film transistor rectifies and converts the pressure into a direct current output, thereby realizing the energy collecting and rectifying functions. In addition, the light-enhanced vibration energy harvesting array of the invention has simple preparation process, is favorable for low-cost large-area preparation, and can meet the requirements of wearable electronics.

Further, the metal is coupled to a current output pole of the light-enhanced vibration energy harvesting device.

For a better understanding and implementation, the invention will be described in detail below with reference to the drawings.

DRAWINGS

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic view showing the structure of a light-enhanced vibration energy harvesting device of the present invention.

2 is a schematic diagram of an equivalent circuit of the vibration energy harvesting device of the present invention.

3 is a schematic view showing the structure of a light-enhanced vibration energy harvesting array of the present invention.

4 is a schematic diagram showing the preparation process of a light-enhanced vibration energy harvesting array.

Figure 5 is a graph of the voltage generated by the device of the present invention for finger bending.

Figure 6 is a graph showing changes in peak power density due to bending of a piezoelectric film of the device of the present invention as a function of bending angle.

Figure 7 is a graph showing the change in voltage across the load of the device with or without illumination.

Figure 8 is a graph showing the voltage variation across the load of the device at different illumination intensities.

detailed description

Please refer to FIG. 1, which is a schematic structural view of a light-enhanced vibration energy harvesting device of the present invention. The light-enhanced vibration energy harvesting device includes a thin film transistor, a piezoelectric unit, an energy storage unit, and a load. The thin film transistor and the piezoelectric unit are bonded by an anisotropic conductive film. The piezoelectric unit is used to collect energy, the thin film transistor is rectified, and the pressure is converted into a direct current output, thereby realizing energy harvesting and rectifying functions. The basic structure of the thin film transistor includes a substrate, a bottom gate, a bottom dielectric layer, a channel, and a top dielectric layer which are stacked from bottom to top. A source and a drain are disposed on both sides of the channel. The energy storage unit and the load are respectively connected to a source of the thin film transistor. In this embodiment, the energy storage unit is a super capacitor.

In this embodiment, the thin film transistor includes a substrate 11, a bottom gate 12 on the upper portion of the substrate 11, a bottom dielectric layer 13 on the upper portion of the bottom gate 12, and a channel 14 on the upper portion of the bottom dielectric layer 13. The source 15 and the drain 16 are respectively located on both sides of the channel 14, and the top dielectric layer 17 and the top gate are located on the upper portion of the channel 14, the source 15 and the drain 16.

The piezoelectric unit includes a piezoelectric film 21 and electrodes 22, 23 which are respectively laminated on the top and bottom of the piezoelectric film 21. In the embodiment, the piezoelectric film 21 is a transparent piezoelectric film, and the electrodes 22 and 23 are transparent conductive materials. The transparent electrode allows light to pass smoothly and reaches the thin film transistor, which receives illumination to enhance the output current.

The bottom electrode 23 of the piezoelectric unit and the top dielectric layer 17 of the thin film transistor are correspondingly bonded by an anisotropic conductive film, so that the piezoelectric unit generates a charge under pressure as a top gate of the thin film transistor. . The bottom electrode of the piezoelectric unit can also be directly fabricated with the top of the thin film transistor. The drain electrode 16 and the bottom gate electrode 12 of the thin film transistor are connected to the bottom electrode 23 of the piezoelectric unit, and the piezoelectric film 21 generates a charge under pressure to act on the top gate, the bottom gate 12 and the drain of the thin film transistor. 16, the transistor produces a current output, and can only be unidirectional, achieving the function of rectification.

In this embodiment, the thin film transistor is a light sensitive amorphous silicon thin film transistor or an organic semiconductor thin film transistor, specifically an amorphous silicon double gate thin film transistor. The piezoelectric film 21 is a PVDF piezoelectric plastic film.

Please refer to FIG. 2, which is an equivalent circuit diagram of the vibration energy harvesting device of the present invention. The equivalent circuit includes a pulse power source S1 formed by a piezoelectric unit, a capacitor C1, a thin film transistor Q1, and a resistive load R. The pulse power source S1 is connected in parallel with the capacitor C1, and one end of the pulse power source S1 is grounded. The other end of the pulse power source S1 is connected to the drain D and the bottom gate G of the thin film transistor Q1. The source S of the thin film transistor Q1 is connected to the resistive load R, and the other end of the resistive load R is connected to one end of the pulsed power source S1 to be grounded. The capacitor C1 is a self-capacitance of the piezoelectric unit. Under the action of pressure, the piezoelectric unit generates a voltage, which acts on the source S, the gate and the drain D of the thin film transistor. When the three electrodes are connected, the thin film transistor is equivalent. In a rectifier diode, the rectification function is realized, and the internal resistance of the thin film transistor is reduced in illumination Low, increasing the output of the current.

Please refer to FIG. 3, which is a schematic structural diagram of a light-enhanced vibration energy harvesting array of the present invention. The light-enhanced vibration energy harvesting array includes a plurality of light-enhanced vibration energy harvesting devices 10, the plurality of light-enhanced vibrations. The energy harvesting devices 10 are arranged in an array, and the adjacent vibrational energy harvesting devices 10 are connected by a metal 20 and connected to the bus 30, thereby reducing the size of the connection resistance. The metal is coupled to a current output pole of the light enhanced vibration energy harvesting device. In this embodiment, the current output is extremely the source of the thin film transistor. The light-enhanced vibration energy harvesting array of the invention collects energy through the piezoelectric unit in the device, rectifies the thin film transistor, converts the pressure into a direct current output, and realizes the energy collecting and rectifying functions. In addition, the light-enhanced vibration energy harvesting array of the invention has simple preparation process, is favorable for low-cost large-area preparation, and can meet the requirements of wearable electronics.

Please refer to FIG. 4 , which is a schematic diagram of a preparation process of a light-enhanced vibration energy harvesting array. The method for preparing the light-enhanced vibration energy harvesting array includes the following steps:

(1) arranging a plurality of thin film transistors in an array to form a thin film transistor array;

(2) attaching an anisotropic conductive film to the thin film transistor array;

(3) forming a plurality of piezoelectric units corresponding to the thin film transistors in an array to form a piezoelectric unit array;

(4) Aligning the piezoelectric unit array with the thin film transistor array electrodes, and then bonding them to obtain a light-enhanced vibration energy harvesting array.

Wherein the anisotropic conductive adhesive film is in contact with the metal electrode under a certain temperature and pressure, so that the thin film transistor and the electrode of the piezoelectric unit are turned on in the vertical direction, and the adjacent thin film transistor and the piezoelectric The electrodes of the unit remain insulated in parallel.

The working process and principle of the light-enhanced vibration energy harvesting device of the present invention are briefly described below:

The piezoelectric film 21 of the piezoelectric unit generates a charge gate to form a top gate of the thin film transistor, and the drain electrode 16 and the bottom gate electrode 12 of the thin film transistor are connected to the bottom electrode 23 of the piezoelectric unit, and the piezoelectric film 21 is Under the action of the pressure, charge is formed on the top gate, the bottom gate 12 and the drain 16 of the thin film transistor, and a current output is generated, and only a single conduction can be performed, thereby realizing the rectification function. Due to the use of the three-dimensional channel structure, the light absorption capability of the channel is enhanced, and under the action of light, the internal resistance of the channel 14 is greatly reduced, and the output current is increased, thereby realizing the effect of light enhancement.

The light-enhanced vibration energy harvesting device is attached to the finger to test the voltage generated by the bending of the finger. Please refer to FIG. 5, which is a voltage generated by the device of the present invention for finger bending. As can be seen from the figure, after the device is attached to the finger, the finger bends to produce a unipolar voltage output, indicating that the current is rectified and passed through the load resistor. Please refer to FIG. 6 , which is a graph showing the peak power density caused by the bending of the piezoelectric film of the device of the present invention as a function of the bending angle, and the rate of change of the peak power density increases gradually as the bending angle increases.

In order to confirm that the vibration energy harvesting device of the present invention does have a light enhancement effect, the device is negative in the presence/absence of light. The voltage at both ends is tested. Please refer to FIG. 7, which is a variation of the voltage across the load of the device with or without illumination. It can be seen from the figure that under the condition of illumination, the voltage across the load increases significantly, indicating that the device is enhanced in output under the action of light. Please refer to FIG. 8, which is a variation of the voltage across the load of the device under different illumination intensities. As can be seen from the figure, as the light intensity increases, the voltage across the load increases significantly, indicating that the device's output increases as the light intensity increases.

Compared with the prior art, the light-enhanced vibration energy harvesting device of the present invention utilizes a piezoelectric unit to collect energy, a thin film transistor rectifies, converts pressure into a direct current output, and the device has a light enhancement effect, that is, a light effect. The output current is increased to increase the energy harvesting efficiency of the device. The preparation process is simple, and the energy harvesting array is prepared at a low cost and large area to meet the requirements of the wearable electron.

The present invention is not limited to the above-described embodiments, and various modifications and variations of the present invention are possible without departing from the spirit and scope of the present invention. Intended to include these changes and modifications.

Claims

A light-enhanced vibration energy harvesting device comprising: a thin film transistor and a piezoelectric unit, the piezoelectric unit being in contact with a top of a thin film transistor as a top gate of the thin film transistor.
The light-enhanced vibration energy harvesting device according to claim 1, wherein said thin film transistor comprises a substrate, a bottom gate located at an upper portion of the substrate, a bottom dielectric layer at an upper portion of the bottom gate, and a bottom dielectric layer. The upper channel of the electrical layer is located at the source and drain on both sides of the channel, and the top dielectric layer on the upper portion of the channel, source and drain.
The light-enhanced vibration energy harvesting device according to claim 2, wherein said light-enhanced vibration energy harvesting device further comprises an energy storage unit and a load, said energy storage unit and said load and said thin film transistor, respectively The source is connected.
A light-enhanced vibration energy harvesting device according to claim 2, wherein said piezoelectric unit comprises a piezoelectric film and electrodes respectively disposed on the top and bottom of the piezoelectric film, and a bottom electrode of said piezoelectric unit Bonded to the top of the thin film transistor or directly on top of the thin film transistor.
The light-enhanced vibration energy harvesting device according to claim 4, wherein the bottom electrode of the piezoelectric unit and the top dielectric layer of the thin film transistor are bonded by an anisotropic conductive film or the piezoelectric unit Prepared on top of the thin film transistor.
The light-enhanced vibration energy harvesting device according to claim 4, wherein the drain electrode and the bottom gate of the thin film transistor are connected to the bottom electrode of the piezoelectric unit.
The light-enhanced vibration energy harvesting device according to claim 4, wherein the piezoelectric film is a transparent piezoelectric film, and the electrodes respectively disposed on the top and bottom of the piezoelectric film are transparent electrodes, and the film The transistor is a photosensitive thin film transistor.
The light-enhanced vibration energy harvesting device according to claim 1, wherein the thin film transistor is an amorphous silicon thin film transistor, a polysilicon thin film transistor or an organic semiconductor thin film transistor; and the piezoelectric film is a PVDF piezoelectric plastic film. .
A light-enhanced vibration energy harvesting array, comprising: a plurality of light-enhanced vibration energy harvesting devices according to any one of claims 1-8, wherein said plurality of light-enhanced vibration energy harvesting devices are arranged in an array Arranged in a manner, the adjacent vibration energy harvesting devices are connected by metal and connected to the bus.
The light-enhanced vibration energy harvesting array of claim 9 wherein said metal is coupled to a current output pole of said light-enhanced vibrational energy harvesting device.