Flexible composite thin film ferroelectric memory and sensors under flexo-photovoltaic effect

Abstract

Flexible composite film ferroelectric memory and sensor under flexoelectric photovoltaic effect. The application relates to the application of a flexoelectric photovoltaic device in a ferroelectric memory, in particular to a flexible composite film with flexoelectric photovoltaic effect and the application in a memory and a sensor. The flexible composite film comprises an organic support film, at least one group of inorganic nanometer arrays is inlaid in the organic support film, and the inorganic nanometer arrays have a flexoelectric effect; any of the inorganic nanometer arrays comprises a plurality of inorganic nanometer tubes or inorganic nanometer fibers arranged in a direction, and the length direction of the inorganic nanometer tubes or inorganic nanometer fibers is less than 30 degrees with the thickness direction of the organic support film. The flexible composite film has the characteristics of high flexoelectric coefficient, large photovoltaic current, good flexibility and no easy failure after repeated bending.

Description

TECHNICAL FIELD

[0001] The present application relates to a polymer thin film under flexoelectric photovoltaic effect and application of a sensor in ferroelectric memory. BACKGROUND

[0002] With the development of electronic technology, the demand for data storage is becoming more and more intense. In addition to the common semiconductor memory device, the ferroelectric material as a memory device has also made great progress. However, the traditional ferroelectric memory needs to be powered on for reading, and repeated reading will cause irreversible damage to the device, and also increase the energy consumption of the ferroelectric memory, which limits the further promotion and application of the ferroelectric memory. To solve this problem, the use of abnormal photovoltaic effect of ferroelectric material for non-destructive storage device has attracted widespread attention in recent research. How to realize the influence on the ferroelectric photovoltaic current by modulating the polarization field in the ferroelectric material is the key to the construction of non-destructive ferroelectric memory device. The common method is to realize the change of the internal polarization field of the ferroelectric material by reversing the electric field. In recent years, the method of adjusting the internal polarization field of the ferroelectric material based on stress has become a new research focus. Flexoelectric photovoltaic effect, that is, using flexoelectric effect to regulate the built-in potential field of ferroelectric semiconductor thin film material, through this scheme, non-destructive reading in ferroelectric storage can be realized. At present, the research on flexoelectric photovoltaic performance materials is mostly based on ceramic thin films, and the flexoelectric coefficient of ceramic thin film is high, the photovoltaic current is large, but the flexibility is poor, and repeated bending is easy to fail. At present, the thin film under flexoelectric photovoltaic effect cannot be used in ferroelectric memory. SUMMARY

[0003] The present application discloses a flexible composite thin film under flexoelectric photovoltaic effect. In the application of ferroelectric memory and sensor, a flexible photoelectric thin film material with high flexoelectric coefficient, large photovoltaic current, good flexibility and not easy to fail after repeated bending is provided.

[0004] In order to achieve the above purpose, the present application provides the following technical scheme:

[0005] The present application provides a flexible composite thin film, which comprises an organic support film, at least one group of inorganic nanometer arrays is embedded in the organic support film, and the inorganic nanometer arrays have flexoelectric effect; any of the inorganic nanometer arrays comprises a plurality of inorganic nanotubes or inorganic nanofibers arranged in a direction, and the length direction of the inorganic nanotubes or inorganic nanofibers is less than 30° with the thickness direction of the organic support film.

[0006] Further, the material of the inorganic nanotube or the inorganic nanofiber is a ferroelectric material.

[0007] Further, the material of the inorganic nanotube or the inorganic nanofiber comprises at least one of lead zirconate titanate, barium titanate or silver niobate.

[0008] Further, the inorganic ceramic nanotube is PbZr 1-x TixO3 nanotube, wherein x is in the range of 0.4-0.5.

[0009] Further, the length direction of the inorganic nanotube or the inorganic nanofiber is consistent with the thickness direction of the organic support film.

[0010] Further, the diameter of the inorganic nanotube or the inorganic nanofiber is 50-500 nm, and the length of the inorganic nanotube or the inorganic nanofiber is 40-150 μm.

[0011] Further, the volume percentage of the inorganic nanotube in the flexible composite film is greater than 0.1% by volume percentage.

[0012] Further, the organic support film comprises polydimethylsiloxane, epoxy resin or polyvinylidene fluoride.

[0013] Further, the bending curvature of the flexible composite film is greater than 34.7 m -1 , and the flexoelectric photovoltaic current is greater than 0.224 nA.

[0014] In a second aspect, the present application provides a memory, comprising at least one storage unit, any of which comprises the flexible composite film of the first aspect of the present application.

[0015] In a third aspect, the present application further provides a sensor, comprising at least one sensing unit, any of which comprises the flexible composite film of the first aspect of the present application.

[0016] The technical solutions of the present application have the following beneficial effects:

[0017] The flexible composite film provided by the present application combines an organic support layer with an inorganic nanotube array for the first time, and develops a film with good flexibility, high flexoelectric coefficient and large photovoltaic current, to meet the application of a new generation of ferroelectric memory. Specifically, the flexible composite film of the present application has the following advantages:

[0018] 1) The inorganic nanometer array in the present application comprises a plurality of inorganic nanometer tubes or inorganic nanometer fibers arranged in a direction, and the included angle between the length direction of the inorganic nanometer tube or inorganic nanometer fiber and the thickness direction of the organic supporting film is less than 30°. When a bending force is applied to the organic supporting film to bend the flexible composite film, the bending force will generate a pressing force on the inorganic nanometer tube or inorganic nanometer fiber, so that the inorganic nanometer tube or inorganic nanometer fiber is bent, thereby causing the inorganic nanometer array to generate a flexoelectric effect, thereby obtaining high flexoelectric performance. Therefore, the flexible composite film provided by the present application can significantly improve the photocurrent generated by the abnormal photovoltaic effect by using the flexoelectric effect.

[0019] 2) The flexible composite material provided by the present application has good flexibility due to the existence of the organic supporting layer. Compared with the traditional ceramic film, the flexible composite film of the present application can maintain high stability under different bending conditions.

[0020] 3) The photovoltaic current of the flexible composite film prepared in the present application has good stability and can still maintain a stable output signal after 1000 cycles.

[0021] 4) The material used in the present application is simple to prepare, has good repeatability and performance stability. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 The structure schematic diagram of the flexible composite film of one embodiment of the present application;

[0023] Figure 2 The structure schematic diagram of the memory of one embodiment of the present application;

[0024] Figure 3 The front view structure schematic diagram of the memory cell of one embodiment of the present application;

[0025] Figure 4 The side view structure schematic diagram of the memory cell of one embodiment of the present application;

[0026] Figure 5 The structure schematic diagram of the memory cell of another embodiment of the present application;

[0027] Figure 6 The PbZrTiO3 inorganic nanometer tube array of one embodiment of the present application; 0.52 Ti 0.48 SEM picture of the PbZrTiO3 inorganic nanometer tube array before packaging;

[0028] Figure 7 The PbZrTiO3 inorganic nanometer tube array of one embodiment of the present application; 0.52 Ti 0.48 SEM picture of the PbZrTiO3 inorganic nanometer tube array after packaging by PDMS;

[0029] Figure 8 A physical photograph of a flexible composite film of an embodiment;

[0030] Figure 9 A structural schematic diagram of a flexoelectric coefficient measuring device;

[0031] Figure 10 A structural schematic diagram of a photoelectric current testing system in a flexoelectric effect;

[0032] Figure 11 A photoelectric current signal testing diagram of corresponding component samples under different curvatures;

[0033] Figure 12 A 1000-cycle stability testing diagram of a flexible composite film of Embodiment 1;

[0034] Figure 13 A structural schematic diagram of a storage unit of an embodiment of the present application;

[0035] Figure 14 A schematic diagram of a data reading mode of a memory.

[0036] Reference signs: 1-memory; 10-storage unit; 100-flexible composite film; 101-organic support film; 102-inorganic nano array; 201-front electrode; 202-back electrode; 30-flexoelectric coefficient measuring device; 301-vibration table; 302-cantilever beam; 303-laser sensor; 304-lock-in amplifier; 305-power amplifier; 40-photoelectric current testing system; 401-laser. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0038] It should be noted that all the embodiments and preferred embodiments mentioned in the present application can be combined to form new technical solutions, unless otherwise specified. All the technical features and preferred features mentioned in the present application can be combined to form new technical solutions, unless otherwise specified. In the present application, unless otherwise specified, the percentage (%) or part refers to the percentage by weight or weight of the composition. In the present application, unless otherwise specified, each component or its preferred component can be combined to form a new technical solution. In the present application, unless otherwise specified, the numerical range "a ~ b" represents a shortcut of any real number combination between a and b, where a and b are real numbers. For example, the numerical range "6 ~ 22" represents that all real numbers between "6 ~ 22" have been listed in this article, and "6 ~ 22" is only a shortcut of these numerical combinations. The lower limit and upper limit of the range disclosed in the present application can be one or more lower limits and one or more upper limits, respectively. In the present application, unless otherwise specified, each reaction or operation step can be performed sequentially or according to the sequence. Preferably, the reaction method in this article is performed sequentially.

[0039] Unless otherwise specified, the professional and scientific terms used in this article have the same meaning as those familiar to those skilled in the art. In addition, any method or material similar or equivalent to the described content can also be applied in the present application.

[0040] The present application provides a flexible composite film. Figure 1 The structure diagram of the flexible composite film of an embodiment of the present application is shown in Figure 1 The flexible composite film 100 includes an organic support film 101, at least one set of inorganic nano arrays 102 is embedded in the organic support film 101, the inorganic nano arrays 102 have flexoelectric effect; any of the inorganic nano arrays 102 includes a plurality of oriented inorganic nanotubes or inorganic nanofibers, the length direction of the inorganic nanotubes or inorganic nanofibers is less than 30° with the thickness direction of the organic support film 101.

[0041] The flexible composite film provided by the present application combines the organic support layer with the inorganic nano array for the first time, develops a film with good flexibility, high flexoelectric coefficient and large photovoltaic current, to meet the application of the new generation of ferroelectric memory. Specifically, the flexible composite film of the present application has the following advantages:

[0042] 1) The inorganic nanometer array in the present application comprises a plurality of inorganic nanometer tubes or inorganic nanometer fibers arranged in a direction, and the angle between the length direction of the inorganic nanometer tubes or inorganic nanometer fibers and the thickness direction of the organic supporting film is less than 30°. When a bending force is applied to the organic supporting film to bend the flexible composite film, the bending force will generate a pressing force on the inorganic nanometer tubes or inorganic nanometer fibers, so that the inorganic nanometer tubes or inorganic nanometer fibers are bent, thereby causing the inorganic nanometer array to generate a flexoelectric effect, thereby obtaining high flexoelectric performance. Thus, the flexible composite film provided by the present application can significantly improve the photocurrent generated by the abnormal photovoltaic effect by using the flexoelectric effect.

[0043] 2) The flexible composite material provided by the present application has good flexibility due to the presence of the organic supporting layer. Compared with the traditional ceramic film, the flexible composite film of the present application can maintain high stability under different bending conditions.

[0044] 3) The photovoltaic current of the flexible composite film prepared in the present application has good stability, and can still maintain a stable output signal after 1000 cycles.

[0045] 4) The material used in the present application is simple to prepare, has good repeatability and performance stability.

[0046] The inorganic nanometer array can be multiple, and the multiple inorganic nanometer arrays are separated by the organic supporting layer. It should be noted that in the present application, the surface of the inorganic nanometer array can be flush with the surface of the organic supporting layer in the thickness direction of the organic supporting layer.

[0047] The inorganic nanometer array can comprise a plurality of inorganic nanometer tubes or inorganic nanometer fibers, and the number of inorganic nanometer tubes or inorganic nanometer fibers can be several, tens, hundreds, thousands, ten thousands, hundreds of thousands or more, which is not specifically limited here.

[0048] In addition, in the flexible composite film of the present application, the angle between the length direction of the inorganic nanometer tubes or inorganic nanometer fibers and the thickness direction of the organic supporting layer is less than 30°, so that the inorganic nanometer array can generate a higher flexoelectric effect when subjected to bending compression.

[0049] In an embodiment of the present application, the length direction of the inorganic nanotube or the inorganic nanofiber is parallel to the thickness direction of the organic supporting film. In this embodiment, the inorganic nanotube or the inorganic nanofiber is perpendicular to the surface of the organic supporting film, and the inorganic nanotube or the inorganic nanofiber distributed perpendicularly has the maximum strain gradient in the bending process. Based on this, in the embodiment of the present application, by adding the inorganic nanotube array structure having the flexoelectric property in the flexible organic supporting layer, the mechanical property of the inorganic nanotube array is increased, and the strain gradient of the inorganic nanotube array coated in the organic supporting layer is improved, thereby significantly increasing the flexoelectric property of the flexible composite film. Thus, the flexoelectric effect of the flexible composite film can be maximally improved.

[0050] In an embodiment of the present application, the material of the inorganic nanotube or the inorganic nanofiber is a material having a ferroelectric property. Specifically, as an exemplary illustration, the material of the inorganic nanotube or the inorganic nanofiber includes, but is not limited to, at least one of lead zirconate titanate, barium titanate or silver niobate.

[0051] The material having the ferroelectric property can separate the electron and hole pairs in the interior of the material under the action of the built-in potential field in the material under the action of the laser of a proper wavelength, thereby forming a stable photocurrent in the external circuit.

[0052] In an embodiment of the present application, the diameter of the inorganic nanotube or the inorganic nanofiber is 50-500 nm, preferably 50-200 nm, and further preferably 100-200 nm; and the length of the inorganic nanotube or the inorganic nanofiber is 40-150 μm, preferably 40-120 μm, and further preferably 40-100 μm. Thus, the flexoelectric effect of the flexible composite film can be maximally improved.

[0053] In an embodiment of the present application, the diameter of the inorganic nanotube or the inorganic nanofiber is 50 nm, 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, 350 nm, 400 nm, 450 nm or 500 nm. The length of the inorganic nanotube or the inorganic nanofiber is 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm or 150 μm.

[0054] In an embodiment of the present application, the volume percentage of the inorganic nanotube array in the flexible composite film is greater than 0.1%, for example, 0.1%-5% by volume.

[0055] In an embodiment of the present application, the organic supporting film can be polydimethylsiloxane, epoxy resin or polyvinylidene fluoride.

[0056] The advantages of combining inorganic nanoarrays with organic support layers are illustrated below using lead zirconate titanate as an example.

[0057] Lead zirconate titanate, such as PbZr 0.52 Ti 0.48 O3 is a common high-performance piezoelectric ceramic material with strong ferroelectric properties. When prepared into nanoscale PbZr... 0.52 Ti 0.48 Following the integration of O3 inorganic nanotubes, the flexural electrical properties of these nanotubes are significantly enhanced due to their small size effect. Furthermore, encapsulating these inorganic nanotubes with polydimethylsiloxane (PDMS) significantly improves their resistance to bending, preventing damage. When one-dimensional inorganic nanotubes are combined with a three-dimensional organic support layer, a 1-3 structure flexible composite film is formed, exhibiting both high flexural electrical properties and significantly enhanced flexural photovoltaic performance under bending conditions.

[0058] In one embodiment of this application, PbZr is encapsulated using PDMS. 1-x Ti x O3 nanotubes (x ranges from 0.4 to 0.5), with only a small amount of PbZr. 1-x Ti x O3 nanotubes (diameter range 180–200 nm, length range 40–60 μm) are encapsulated within a flexible PDMS polymer (content 0.1–5 vol%) to obtain a flexible composite film. The PDMS polymer forms an organic support layer. The resulting flexible composite film exhibits significantly improved flexural electrical properties. The photocurrent of the flexible composite film can be controlled by adjusting its curvature; for example, when the curvature of the flexible composite film is 34.7 μm... -1 At that time, the flexural photovoltaic current can reach 0.224nA.

[0059] Based on the same technical concept, this application also provides a memory. Figure 2 This is a schematic diagram of the structure of a memory according to an embodiment of this application, as shown below. Figure 2 As shown, the memory 1 includes at least one storage unit 10. Any of the storage units 10 may include a flexible composite film 100 from the embodiments of the present application above.

[0060] Figure 3 This is a front view structural diagram of a storage cell according to an embodiment of this application. Figure 4 This is a side view of a storage cell according to an embodiment of this application. Figure 3 and Figure 4As shown, any storage unit 10 of the memory 1 of an embodiment of the present application comprises, in addition to the flexible composite film 100 of the embodiment of the present application, a front electrode 201 and a back electrode 202 arranged on the surface of the flexible composite film 100, and the front electrode 201 and the back electrode 202 are arranged on the two surfaces of the flexible composite film 100 respectively. The front electrode 201 can be an ITO electrode, and the back electrode 202 can be a gold electrode. It should be noted that the ITO electrode can only cover the surface of the inorganic nano array 102. When the flexible composite film 100 comprises a plurality of inorganic nano arrays 102, for example, 5, 10 or more inorganic nano arrays 102, any two inorganic nano arrays 102 are arranged with a spacing, and the ITO electrode for connecting the inorganic nano array 102 can also be arranged with a spacing.

[0061] With reference to the foregoing Figure 3 and Figure 4 In an embodiment of the present application, the back electrode 202 can be arranged on the entire surface of the flexible composite film 100 opposite to the front electrode 201.

[0062] Figure 5 The structure of the storage unit of another embodiment of the present application is shown in the figure. Figure 5 As shown, in an embodiment of the present application, the back electrode 202 can cover the surface of the inorganic nano array 102.

[0063] The memory of the embodiment of the present application mainly comprises a transparent ITO electrode, a back electrode and a flexible composite film. This memory can write data information by polarizing the flexible composite film, and realize information reading by reading photoelectric current under the action of laser. In the reading process, in order to increase the generated photoelectric current, the memory can be bent at a certain angle, so as to increase the generated photoelectric current.

[0064] The memory of the embodiment of the present application can use laser to excite the electrons in the interior of the flexible composite film when reading data information. Since the electron-hole pairs are separated under different polarization fields due to different polarization states, different intensity of photoelectric current signals can be generated, so that the information in the memory can be read without damage.

[0065] In addition, in order to further improve the photoelectric current of the memory and expand the use range of the memory, the flexoelectric effect is used in the present application to improve the photoelectric current of the memory, and the strain information is added to the storage information of the memory. That is, by using the flexoelectric effect, on the one hand, the photoelectric current of the ferroelectric memory can be improved; on the other hand, the information of the change of the photoelectric current due to the strain can be added to the information stored in the conventional ferroelectric memory.

[0066] With reference to the foregoing Figure 2The memory 1 can include a plurality of storage units 10, and the number of the storage units 10 can be one, two, three, five, ten, twenty or more. Any storage unit 10 corresponds to at least one inorganic nano array.

[0067] The memory can determine the information written in the inorganic nano array in different polarization states according to the photocurrent generated by each storage unit under the action of laser. Since the flexoelectric effect can significantly enhance the photocurrent signal, after stress is applied to the memory, the stress applied to the memory can also be detected by detecting the change of the photocurrent.

[0068] Based on the same technical concept, the application also provides a sensor which can also include a flexible composite film in any of the embodiments of the application. Similar to the memory provided in the embodiments of the application, the memory in the embodiments of the application, in addition to including the flexible composite film in the embodiments of the application, also includes a front electrode and a back electrode arranged on the surface of the flexible composite film, and the front electrode and the back electrode are arranged on the two side surfaces of the flexible composite film, respectively.

[0069] In detection, for the polarized inorganic nano array in the same structural unit, the photocurrent under different bending curvatures can reflect the stress suffered by the structural unit. The structure of the sensor in this embodiment can be described in the same way as the structure of the memory in the embodiments of the application, and will not be described here.

[0070] Embodiment 1

[0071] This embodiment is a flexible composite film, which encapsulates PbZr 0.52 Ti 0.48 O3 nanotubes with PDMS as the matrix, and the preparation method thereof includes the following steps:

[0072] Step S11), PbZr 0.52 Ti 0.48 O3 nanotubes are prepared by using a template method:

[0073] First, lead acetate trihydrate, zirconyl nitrate, tetrabutyl titanate, acetylacetone and formamide are dissolved in ethylene glycol monomethyl ether, and refluxed and cooled at 80°C for 2h to synthesize PbZr 0.52 Ti 0.48 O3 nanotube gel precursor (0.3mol / L). Among them, acetylacetone is used as a titanium stabilizer, and formamide is used as a chemical modifier. Then, in a negative pressure environment, PbZr 0.52 Ti 0.48The O3 nanotube gel precursor solution was dropped into a commercial alumina (AAO) template (pore size 200 nm, pore depth 50 μm). The dried template was annealed in a muffle furnace (625-725 °C) for 1-6 h in air to form the perovskite structure. In this embodiment, a controlled ramping rate, i.e. 1 °C / min for heating and 3 °C / min for cooling, was used to remove the residual organic material and to protect the as-formed crystalline inorganic nanotube array. The ceramic coating on the surface of the AAO template was removed by ionized etching (ICP) for 5 min. The AAO template with the inorganic nanotube array was then immersed in a 2 mol / L NaOH solution to dissolve the AAO template and obtain the inorganic nanotube array. The sample surface was then cleaned with deionized water to remove the residual solution.

[0074] Step S12), 100 μl of PDMS solution (5:1, PDMS: silane coupling agent) was prepared, and then the PbZr 0.52 Ti 0.48 The inorganic nanotube array of PbZr -1 TiO3 was fixed on a spin coater, and the prepared PDMS solution was spin-coated at a rotation speed of 3500 r / min. The obtained thin film was dried at 65 °C for 4 h to ensure the solidification of the PDMS. Then the sample was reversed, and the other side of the sample was spin-coated. After the spin-coating, the sample was placed under negative pressure to allow the PDMS to fully penetrate between the inorganic nanotube array. Then the sample was dried at the same temperature for 4 h to obtain the flexible composite thin film. In the obtained flexible composite thin film, the volume percentage of PZT was 0.96 vol.%.

[0075] Step S13), the prepared flexible composite thin film was used to sputter a circular electrode with a diameter of 13 mm on the surface of the flexible composite thin film by a magnetron sputtering process to form a test sample. In this embodiment, indium tin oxide (ITO) and gold were used as the electrode as the front electrode and the back electrode, respectively, to perform the photoelectric current test of the flexoelectric effect and the measurement of the flexoelectric coefficient.

[0076] Figure 6 The SEM image of the inorganic nanotube array of PbZr 0.52 Ti 0.48 O3 before packaging. Figure 7 The SEM image of the inorganic nanotube array of PbZr 0.52 Ti 0.48 O3 after packaging by PDMS. Figure 8 A photograph of a flexible composite thin film. As shown in Figure 6 and Figure 7 , in the inorganic nanotube array obtained in Embodiment 1 of the present application, a plurality of inorganic nanotubes grow in one direction, wherein Figure 6 andFigure 7 The direction shown in the figure is the direction of growth of the inorganic nanotube, Figure 6 In the figure, the growth direction of the inorganic nanotube is perpendicular to the direction of the paper, Figure 7 In the figure, the growth direction of the inorganic nanotube is the vertical direction. It has been tested that the length of a single inorganic nanotube is 40-60 μm, and the diameter is 200 nm.

[0077] Example 2-3

[0078] Examples 2-3 are all flexible composite films, which are different from Example 1 in that the volume percentage of PZT in the obtained flexible composite film is different. In Example 2, the volume percentage of PZT is 1.4 vol.%, and in Example 3, the volume percentage of PZT is 1.9 vol.%. The specific preparation method can refer to Example 1.

[0079] Comparative Example 1

[0080] This comparative example is a PDMS film, and ITO electrodes and gold electrodes are respectively arranged on the two surfaces of the PDMS film.

[0081] The flexoelectric coefficient, the photovoltage of the flexoelectric photoelectric effect, the photovoltage signal of the corresponding component sample under different curvatures of Example 1, and the 1000-cycle stability test of the flexible composite film of Example 1 are tested respectively. The specific test data are shown in Table 1.

[0082] Figure 9 It is a flexoelectric coefficient measuring device, which is composed of a vibration table (Shaker), a cantilever beam (Cantilever beam), a photonic sensor (Photonic sensor), a lock-in amplifier (Lock-in amplifier) and a power amplifier (Power amplifier).

[0083] Figure 10 It is a photovoltage test system in the flexoelectric photoelectric effect, which is composed of a laser (Laser, 405 nm), a chopper (Chopper), a filter (Filter), and an amplifier (Amplifier) and a lock-in amplifier (Lock-in amplifier).

[0084] Figure 11 It is the photovoltage signal of the corresponding component sample under different curvatures. Figure 12 It is the 1000-cycle stability test of the flexible composite film of Example 1.

[0085] Table 1

[0086]

[0087] From the data in Table 1, it can be seen that by compounding the organic supporting layer with the inorganic nanotube array, the flexoelectric coefficient and the flexoelectric photovoltaic current of the flexible composite film can be significantly improved.

[0088] In addition, as shown in Figure 12 After 1000 cycles of testing, the flexible composite film of the embodiment of the present application still has stable current output, indicating that the flexible composite film of the present application has good stability.

[0089] Using the above material, an integrated flexoelectric photovoltaic ferroelectric memory device is designed in the present application.

[0090] Figure 13 The device unit is a single structure memory cell for the memory, which has a PDMS-PZT film as a functional layer, an ITO transparent electrode as an upper electrode, and a gold electrode as a lower electrode. The specific parameters of the memory cell are as follows: the ITO electrode layer of the upper electrode has a thickness of 100 nm, a length of 1 mm, a width of 1 mm, and a pin of 0.25*0.25 mm; the gold electrode of the lower electrode has a thickness of 100 nm, a length of 1 mm, a width of 1 mm, and a pin of 0.25*0.25 mm; and the performance layer in the middle is a PDMS-PZT nanocomposite film with a length of 1.5 mm, a width of 1.5 mm, and a thickness of 200 μm. The flexoelectric photovoltaic memory integrated with the memory cell is as shown in Figure 13 Figure 2 Figure 14 A schematic diagram of a data reading mode for the memory. In the reading mode, a laser with a spot smaller than the electrode area is used to irradiate the surface of the PDMS-PZT flexoelectric photovoltaic memory cell. The obtained photocurrent signal is read by a current amplifier, and the corresponding strain information can also be detected due to the influence of different bending curvatures on the photocurrent.

[0091] Obviously, those skilled in the art can make various modifications and variations to the embodiments of the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application also intends to include these modifications and variations.​​

Claims

1. A flexible composite film, characterized in that, The organic support film includes at least one set of inorganic nanoarrays embedded therein, the inorganic nanoarrays having flexural electrical effects; Each of the inorganic nanoarrays includes multiple oriented inorganic nanotubes or inorganic nanofibers, wherein the angle between the length direction of the inorganic nanotubes or inorganic nanofibers and the thickness direction of the organic support film is less than 30°.

2. The flexible composite film according to claim 1, characterized in that, The inorganic nanotubes or inorganic nanofibers are made of materials with ferroelectric properties.

3. The flexible composite film according to claim 2, characterized in that, The inorganic nanotubes or inorganic nanofibers are made of at least one of lead zirconate titanate, barium titanate, or silver niobate.

4. The flexible composite film according to any one of claims 1-3, characterized in that, The length direction of the inorganic nanotube or the inorganic nanofiber is parallel to the thickness direction of the organic support film.

5. The flexible composite film according to any one of claims 1-3, characterized in that, The inorganic nanotubes or inorganic nanofibers have a diameter of 50–500 nm and a length of 40–150 μm.

6. The flexible composite film according to any one of claims 1-3, characterized in that, The inorganic nanoarray accounts for more than 0.1% of the volume of the flexible composite film by volume percentage.

7. The flexible composite film according to any one of claims 1-3, characterized in that, The organic support membrane includes polydimethylsiloxane, epoxy resin, or polyvinylidene fluoride.

8. The flexible composite film according to any one of claims 1-3, characterized in that, The flexible composite film has a bending curvature greater than 34.7 m. -1 At that time, the flexural photovoltaic current is greater than 0.224nA.

9. A memory, characterized in that, It includes at least one storage unit, and any one of the storage units includes the flexible composite film according to any one of claims 1-8.

10. A sensor, characterized in that, It includes at least one sensing unit, and any one of the sensing units includes the flexible composite film according to any one of claims 1-8.

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