Flexible photoelectric double-control memristor and preparation method and application thereof

Abstract

The invention relates to a flexible photoelectric double-control memristor and a preparation method and application thereof.The flexible photoelectric double-control memristor comprises a flexible substrate, a bottom electrode, a composite function film and a top electrode which are sequentially arranged in a stacked mode, the bottom electrode and the top electrode are both made of silver, and the composite function film is made of silicon. The composite functional film comprises a copper-based perovskite layer and a first hydrophobic polymer layer which are laminated, the top electrode is laminated on the first hydrophobic polymer layer, and the top electrode does not completely cover the first hydrophobic polymer layer. The flexible photoelectric double-control memristor shows various typical photoelectric synaptic plasticity under the stimulation of optical signals, is hardly influenced by the bending curvature, the bending cycle index and the environment, and can be well applied to flexible electronic products.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic materials, and particularly to a flexible optoelectronic dual-control memristor and its preparation method and application. Background Art

[0002] In recent years, flexible electronic products have shown great research potential in the fields of wireless sensors, bendable mobile phones, wearable electronic devices, etc. As one of the crucial components in such devices, the construction of flexible optoelectronic dual-control memristors has become a current research hotspot. Traditional flexible optoelectronic dual-control memristors are mainly two-dimensional layered organic-inorganic lead halide perovskite-based memristors. Although such flexible optoelectronic dual-control memristors exhibit excellent memristive properties, the toxicity of the lead they contain cannot be ignored. To reduce toxicity, researchers have tried to use elements such as bismuth (III), antimony (III), or tin (II) to replace lead (II). However, trivalent cations including antimony (III) and bismuth (III) elements are difficult to form a two-dimensional layered structure, and tin (II) elements are easily oxidized to the more stable tin (IV). Therefore, there is an urgent need to develop a stable and reliable flexible optoelectronic dual-control memristor suitable for flexible scenarios. Summary of the Invention

[0003] Based on this, in view of the above problems, it is necessary to provide a flexible optoelectronic dual-control memristor and its preparation method and application. This flexible optoelectronic dual-control memristor exhibits various typical optoelectronic synaptic plasticities under light signal stimulation, and is almost unaffected by the bending curvature, the number of bending cycles, and the environment, and can be well applied to flexible electronic products.

[0004] The present invention discloses a flexible optoelectronic dual-control memristor, which includes a flexible substrate, a bottom electrode, a composite functional thin film, and a top electrode stacked in sequence. Among them, the materials of the bottom electrode and the top electrode are both selected from silver. The composite functional thin film includes a copper-based perovskite layer and a first hydrophobic polymer layer stacked. The top electrode is stacked on the first hydrophobic polymer layer, and the top electrode does not completely cover the first hydrophobic polymer layer.

[0005] In one embodiment, the composite functional thin film further includes a second hydrophobic polymer layer. The second hydrophobic polymer layer is stacked between the copper-based perovskite layer and the bottom electrode. The thickness ratio of the copper-based perovskite layer to the second hydrophobic polymer layer is 1:1.4 - 1:2.1.

[0006] In one embodiment, the copper-based perovskite layer is selected from (C 6 H 5 CH 2 NH 3 ) 2 CuBr 4Layer, (CH 3 NH 3 )CuBr 3 layer or (CH(NH 2 ) 2 ) 2 CuI 4 layer.

[0007] In one embodiment, the thickness ratio of the copper-based perovskite layer to the first hydrophobic polymer layer is 1:1.4 - 1:2.1.

[0008] In one embodiment, the thickness of the copper-based perovskite layer is less than or equal to 50 nm.

[0009] In one embodiment, the flexible optoelectronic dual-control memristor satisfies at least one of the following conditions: (1) The flexible substrate is selected from a flexible mica substrate, a polyimide substrate, or a polyethylene terephthalate substrate; (2) The first hydrophobic polymer layer is selected from a polymethyl methacrylate layer, a parylene layer, or a polyurethane layer; (3) The thickness of the top electrode is 90 nm - 110 nm; (4) The thickness of the bottom electrode is 90 nm - 110 nm.

[0010] A method for preparing a flexible optoelectronic dual-control memristor as described above, comprising the following steps: Form a bottom electrode on the surface of the flexible substrate, and the material of the bottom electrode is selected from silver; First, form a copper-based perovskite layer on the surface of the bottom electrode, and then form a first hydrophobic polymer layer on the surface of the copper-based perovskite layer away from the bottom electrode, and the copper-based perovskite layer and the first hydrophobic polymer layer form a composite functional thin film; and Form a top electrode on the surface of the composite functional thin film, and the material of the top electrode is selected from silver, to obtain a flexible optoelectronic dual-control memristor.

[0011] In one embodiment, when the copper-based perovskite layer is selected from (C 6 H 5 CH 2 NH 3 ) 2 CuBr 4 layer, the step of forming the copper-based perovskite layer on the surface of the bottom electrode includes: Dissolve C 6 H 5 CH 2 NH 3 Br and CuBr 2 in a solvent to obtain a precursor solution; Form the precursor solution on the surface of the bottom electrode, and form a copper-based perovskite layer after heat annealing.

[0012] In one embodiment, in the precursor solution, the 6 H 5 CH 2 NH 3 molar ratio of Br to CuBr 2 is 1.8:1 - 2.2:1, and the mass fraction of 6 H 5 CH 2 NH 3 Br is 60% - 68%; and / or, the heat annealing temperature is 70°C - 80°C, and the time is 30 min - 50 min.

[0013] Application of a flexible optoelectronic dual-control memristor of copper-based perovskite as described above in a neuromorphic circuit system.

[0014] In the flexible optoelectronic dual-control memristor provided by the present invention, the materials of the bottom electrode and the top electrode are both selected from silver, and the bottom electrode, the composite functional thin film, and the top electrode are sequentially stacked. Among them, an Ag conductive filament can be formed between the bottom electrode and the top electrode, and the copper-based perovskite layer in the composite functional thin film can generate additional electron-hole pairs under ultraviolet irradiation; under the action of an external voltage, the photo-induced electron-hole pairs split and move in opposite directions, forming an internal electric field in the same direction as the applied electric field, which helps the formation and breakage of the Ag conductive filament. Therefore, under ultraviolet irradiation, the on-off ratio of the flexible optoelectronic dual-control memristor can be increased to more than 60, which is more than 6 times that under non-ultraviolet irradiation conditions. Thus, after continuous ultraviolet stimulation, the flexible optoelectronic dual-control memristor provided by the present invention can effectively regulate the conductivity of the flexible optoelectronic dual-control memristor, realizing a process similar to the "learning-forgetting-relearning" of the brain, and exhibiting various typical optoelectronic synaptic plasticities under optical signal stimulation.

[0015] In addition, in the flexible optoelectronic dual-control memristor based on copper-based perovskite materials provided by the present invention, the bottom electrode, the composite functional thin film, and the top electrode all have excellent bending resistance. At the same time, the first hydrophobic polymer layer in the composite functional thin film can reduce the direct contact between the copper-based perovskite layer and water, thereby improving the humidity stability of the copper-based perovskite layer. Therefore, the flexible optoelectronic dual-control memristor is hardly affected by the bending curvature, the number of bending cycles, and the environment, and can be well applied to flexible electronic products. Description of the Drawings

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0017] Figure 1 Schematic structural diagram of a flexible optoelectronic dual - controlled memristor according to an embodiment provided by the present invention; Figure 2 Schematic structural diagram of a flexible optoelectronic dual - controlled memristor according to another embodiment provided by the present invention; Figure 3 XRD spectrum of the copper - based perovskite layer in Example 1; Figure 4 Test results of the influence of mechanical bending on the electrical properties of the flexible optoelectronic dual - controlled memristor provided in Example 1 in Test Example 1; Figure 5 Test results of the ultraviolet radiation response characteristics of the flexible optoelectronic dual - controlled memristor provided in Example 1 in Test Example 2; Figure 6 Test results of the ultraviolet radiation response characteristics of the flexible optoelectronic dual - controlled memristor provided in Example 1 in different forms of ultraviolet radiation in Test Example 3; Figure 7 Test results of the ultraviolet radiation response characteristics of the flexible optoelectronic dual - controlled memristor provided in Comparative Example 1 in Test Example 4; Figure 8 Test results of the ultraviolet radiation response characteristics of the flexible optoelectronic dual - controlled memristor provided in Example 1 in Test Example 4.

[0018] In the figure, 10 is a flexible substrate; 20 is a bottom electrode; 30 is a composite functional film; 301 is a copper - based perovskite layer; 302 is a first hydrophobic polymer layer; 303 is a second hydrophobic polymer layer; 40 is a top electrode. Detailed implementation manners

[0019] To facilitate the understanding of the present invention, the following will describe the present invention in more detail. However, it should be understood that the present invention can be implemented in many different forms and is not limited to the embodiments or examples described herein. On the contrary, the purpose of providing these embodiments or examples is to make the understanding of the disclosed content of the present invention more thorough and comprehensive.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field of the present invention. The terms used herein in the specification of the present invention are for the purpose of describing specific embodiments or examples only and are not intended to limit the present invention.

[0021] In the first aspect of the present invention, as Figure 1 shown, a flexible optoelectronic dual-controlled memristor is provided, which includes a flexible substrate 10, a bottom electrode 20, a composite functional thin film 30, and a top electrode 40 that are sequentially stacked. Among them, the materials of the bottom electrode 20 and the top electrode 40 are both selected from silver. The composite functional thin film 30 includes a copper-based perovskite layer 301 and a first hydrophobic polymer layer 302 that are stacked. The first hydrophobic polymer layer 302 is attached to the top electrode 40, and the top electrode 40 does not completely cover the first hydrophobic polymer layer 302.

[0022] In the flexible optoelectronic dual-controlled memristor provided by the present invention, the materials of the bottom electrode 20 and the top electrode 40 are both selected from silver, and the bottom electrode 20, the composite functional thin film 30, and the top electrode 40 are sequentially stacked. Among them, an Ag conductive filament can be formed between the bottom electrode 20 and the top electrode 40, and the copper-based perovskite layer 301 in the composite functional thin film 30 can generate additional electron-hole pairs under ultraviolet irradiation; under the action of an external voltage, the photo-induced electron-hole pairs split and move in opposite directions to form an internal electric field in the same direction as the applied electric field, which helps the formation and breakage of the Ag conductive filament. Therefore, under ultraviolet irradiation, the on-off ratio of the flexible optoelectronic dual-controlled memristor can be increased to more than 60, which is more than 6 times that under non-ultraviolet irradiation conditions. Thus, the flexible optoelectronic dual-controlled memristor provided by the present invention can effectively regulate the conductivity of the flexible optoelectronic dual-controlled memristor after continuous ultraviolet stimulation, realizing a "learning-forgetting-relearning" process similar to that of the brain, and exhibiting various typical optoelectronic synaptic plasticities under optical signal stimulation.

[0023] In one embodiment, the copper-based perovskite layer 301 is selected from (C 6 H 5 CH 2 NH 3 ) 2 CuBr 4 layer, (CH 3 NH 3 )CuBr 3 layer or (CH(NH 2 ) 2 ) 2 CuI 4Layer; preferably, the thickness of the copper-based perovskite layer 301 is less than or equal to 50 nm, including but not limited to 5 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm or 50 nm. Within the above range, the thickness of the copper-based perovskite layer 301 affects the turn-on voltage of the flexible optoelectronic dual-control memristor. The smaller the thickness of the copper-based perovskite layer 301, the smaller the turn-on voltage.

[0024] In one embodiment, the thickness of the top electrode 40 is 90 nm - 110 nm; the thickness of the bottom electrode 20 is 90 nm - 110 nm. Within the above range, the thicknesses of the top electrode 40 and the bottom electrode 20 affect the ohmic contact effect between them and the composite functional thin film 30. The greater the thicknesses of the top electrode 40 and the bottom electrode 20, the better the ohmic contact effect between the top electrode 40 and the bottom electrode 20 and the composite functional thin film 30.

[0025] In addition, in the flexible optoelectronic dual-control memristor based on the copper-based perovskite material provided by the present invention, the bottom electrode 20, the composite functional thin film 30 and the top electrode 40 all have excellent bending resistance. At the same time, the hydrophobic polymer layer in the composite functional thin film 30 can reduce the direct contact between the copper-based perovskite layer 301 and water, thereby improving the humidity stability of the copper-based perovskite layer 301. Therefore, the flexible optoelectronic dual-control memristor is hardly affected by the bending curvature, the number of bending cycles and the environment, and can be well applied to flexible electronic products.

[0026] In another embodiment, as Figure 2 shown, the composite functional thin film 30 further includes a second hydrophobic polymer layer 303. The second hydrophobic polymer layer 303 is attached to the copper-based perovskite layer 301 and the bottom electrode 20, thereby further reducing the direct contact between the copper-based perovskite layer 301 and water, and further improving the humidity stability of the copper-based perovskite layer 301.

[0027] In one embodiment, the first hydrophobic polymer layer 302 is selected from a polymethyl methacrylate layer, a polyimide layer or a polyethylene terephthalate layer; preferably, the first hydrophobic polymer layer 302 is selected from a polymethyl methacrylate layer.

[0028] In one embodiment, the thickness ratio of the copper-based perovskite layer 301 to the first hydrophobic polymer layer 302 is from 1:1.4 to 1:2.1, including but not limited to 1:1.4, 1:1.45, 1:1.5, 1:1.55, 1:1.6, 1:1.7, 1:1.8, 1:1.9, 1:1.2, 1:2.1. Within the above range, the thickness ratio affects the switching voltage and thermal stability of the flexible optoelectronic dual-control memristor. The smaller the thickness ratio, the smaller the switching voltage. The larger the thickness ratio, the better the thermal stability. In one embodiment, the thickness of the first hydrophobic polymer layer is 70 nm - 90 nm, including but not limited to 70 nm, 72 nm, 74 nm, 76 nm, 78 nm, 80 nm, 82 nm, 84 nm, 86 nm, 88 nm, or 90 nm.

[0029] In one embodiment, the selection of the thickness and type of the second hydrophobic polymer layer 303 can refer to the thickness and type of the first hydrophobic polymer layer 302.

[0030] In one embodiment, the material of the flexible substrate 10 is selected from a flexible mica substrate; the thickness is 40 μm - 60 μm, including but not limited to 40 μm, 45 μm, 50 μm, 55 μm, or 60 μm.

[0031] In a second aspect of the present invention, there is provided a method for manufacturing a flexible optoelectronic dual-control memristor as described above, including the following steps: S10, forming a bottom electrode 20 on the surface of the flexible substrate 10, and the material of the bottom electrode 20 is selected from silver; S20, first forming a copper-based perovskite layer 301 on the surface of the bottom electrode 20, and then forming a first hydrophobic polymer layer 302 on the surface of the copper-based perovskite layer 301 away from the bottom electrode 20. The copper-based perovskite layer 301 and the first hydrophobic polymer layer 302 form a composite functional thin film 30; and S30, forming a top electrode 40 on the surface of the composite functional thin film 30, and the material of the top electrode 40 is selected from silver, to obtain a flexible optoelectronic dual-control memristor.

[0032] In step S10, there is no limitation on the method of forming the bottom electrode 20 on the surface of the flexible substrate 10. In one embodiment, the bottom electrode 20 is formed on the surface of the flexible substrate 10 by means of magnetron sputtering. Preferably, the process parameters of magnetron sputtering are: the sputtering power is 75 W - 85 W, the sputtering time is 35 min - 45 min, the sputtering temperature is 95 °C - 105 °C, and the process pressure is 0.8 Pa - 1.2 Pa.

[0033] In one embodiment, before the step of forming the bottom electrode 20 on the surface of the flexible substrate 10, the flexible substrate 10 is cleaned to remove the contaminants on the surface of the flexible substrate 10. The cleaning process depends on the type of the flexible substrate 10. When the flexible substrate 10 is selected from flexible mica substrates, the flexible mica substrate is cleaned successively with ethanol and water.

[0034] In step S20, there is no limitation on the method of forming the copper-based perovskite layer 301 on the surface of the bottom silver electrode and forming the first hydrophobic polymer layer 302 on the surface of the copper-based perovskite layer 301 away from the bottom electrode 20. In one embodiment, when the molecular formula of the copper-based perovskite is (C 6 H 5 CH 2 NH 3 ) 2 CuBr 4 ), the step of forming the copper-based perovskite layer 301 on the surface of the second silver electrode includes: S201, dissolving C 6 H 5 CH 2 NH 3 Br and CuBr 2 in a solvent to obtain a precursor solution; S202, forming the precursor solution on the surface of the second electrode and forming the copper-based perovskite layer 301 after heat annealing.

[0035] In step S201, in order to better dissolve C 6 H 5 CH 2 NH 3 Br and CuBr 2 , preferably, the solvent is selected from at least one of N,N-dimethylformamide, dimethyl sulfoxide or dimethylacetamide.

[0036] In one embodiment, in the precursor solution, the molar ratio of C 6 H 5 CH 2 NH 3 Br to CuBr 2 is 1.8:1 - 2.2:1, so as to avoid the residue of C 6 H 5 CH 2 NH 3 Br or CuBr 2 in the copper-based perovskite layer 301, which affects the optoelectronic performance of the flexible optoelectronic dual-control memristor.

[0037] In one embodiment, C 6 H 5 CH 2 NH3 The mass fraction of Br in the precursor solution is 60% - 68%, including but not limited to 60%, 61%, 62%, 63%, 64%, 64.33%, 65%, 66%, 67% or 68%.

[0038] In step S202, before the step of forming the precursor solution on the surface of the second electrode, the precursor solution is filtered, preferably using a filter with a pore size of 0.20 µm - 0.4 µm to filter the precursor solution.

[0039] In one embodiment, the temperature of the heat annealing is preferably 70°C - 80°C, and the time is preferably 30 min - 50 min.

[0040] In one embodiment, the step of forming the hydrophobic polymer layer on the surface of the copper-based perovskite layer 301 includes: first forming the polymer solution on the surface of the copper-based perovskite layer 301, and then annealing the hydrophobic polymer layer.

[0041] In step S30, there is no limitation on the method of forming the first silver electrode on the surface of the hydrophobic polymer layer. In one embodiment, the first silver electrode is formed on the surface of the hydrophobic polymer layer by magnetron sputtering; preferably, the process parameters of magnetron sputtering are: the sputtering power is 75 W - 85 W, the sputtering time is 35 min - 45 min, the sputtering temperature is 95°C - 105°C, and the process pressure is 0.8 Pa - 1.2 Pa.

[0042] In the third aspect of the present invention, there is provided an application of the flexible optoelectronic dual-control memristor of the copper-based perovskite as described above in a neuromorphic circuit system.

[0043] Hereinafter, the flexible optoelectronic dual-control memristor, its preparation method and application will be further described through the following specific examples.

[0044] Example 1 A flexible mica substrate with a thickness of 50 µm is used as the flexible substrate 10. The flexible mica substrate is ultrasonically cleaned with ethanol and deionized water in sequence to remove surface stains. A silver electrode with a thickness of 100 nm is formed on the flexible mica substrate by magnetron sputtering as the bottom electrode 20 to obtain a silver-plated mica substrate. The silver-plated mica substrate is further cleaned by ultraviolet ozone for 30 minutes.

[0045] Mix HBr and C 6 H 5 CH 2 NH 3 Mix them in a molar ratio of 1:1 and put them into 10 mL of ethanol, and then put the mixture into an ice bath and stir for 3 hours to synthesize C 6 H 5 CH2 NH 3 Br solution. The obtained C 6 H 5 CH 2 NH 3 Br solution was placed on an evaporation platform at 60 °C for evaporation. The white precipitate was collected and washed six times with ether. The obtained white precipitate was dried in an oven at 60 °C for 60 hours. The synthesized C 6 H 5 CH 2 NH 3 Br and CuBr 2 were dissolved in 0.2 mL of N,N-dimethylformamide according to a molar ratio of 2:1 to prepare a 0.5 mol / L precursor solution. The prepared precursor solution was filtered through a filter with a pore size of 0.20 µm and spin-coated on a silver-plated mica substrate, and then annealed on a heating platform at 75 °C for 40 minutes to form a copper-based perovskite layer 301 with a thickness of 40 nm. The XRD spectrum of the copper-based perovskite layer 301 is as Figure 3 shown. It can be seen from Figure 3 that the XRD characteristic peaks of (C 6 H 5 CH 2 NH 3 ) 2 CuBr 4 do not overlap with the peaks of the original C 6 H 5 CH 2 NH 3 Br and CuBr 2 , indicating that no raw material residues were detected in the copper-based perovskite layer 301.

[0046] A polymethyl methacrylate solution was spin-coated on the surface of the copper-based perovskite layer 301 and annealed at 50 °C for 5 minutes to form a polymethyl methacrylate layer with a thickness of 80 nm as the first hydrophobic polymer layer 302.

[0047] A circular silver electrode with a thickness of 100 nm and a diameter of 100 µm was deposited on the surface of the polymethyl methacrylate layer by magnetron sputtering as the top electrode 40, and a flexible optoelectronic dual-control memristor was obtained.

[0048] Test Example 1 Test the effect of mechanical bending on the electrical properties of the flexible optoelectronic dual-control memristor prepared in Example 1. The test results are as Figure 4 shown. Figure 4 In (a) of [], a schematic structural diagram of the flexible optoelectronic dual-control memristor in the bent state is shown. The bending degree of the flexible optoelectronic dual-control memristor can be adjusted by changing the length of L. The shorter L is, the greater the bending degree of the flexible optoelectronic dual-control memristor is.Figure 4 In (b), when L is 16 mm, 12 mm, and 8 mm respectively, the I-V (current-voltage) characteristic curves under continuous negative and positive voltage scans are shown. These I-V characteristic curves indicate that the flexible optoelectronic dual-control memristor can still exhibit gradual memristive behavior under different bending conditions. Figure 4 In (c), when L is 16 mm, the current fluctuations of the flexible optoelectronic dual-control memristor in two different resistance states with the number of bending cycles are shown. From Figure 4 As can be seen from (c), after 500 bending cycles, the high resistance state (HRS) and low resistance state (LRS) of the flexible optoelectronic dual-control memristor remain relatively stable. This result indicates that the flexible optoelectronic dual-control memristor has good mechanical flexibility.

[0049] Test Example 2 The response characteristics of the flexible optoelectronic dual-control memristor prepared in Test Example 1 to ultraviolet (UV) radiation were tested. The test results are as Figure 5 shown. Figure 5 In (a), the I-V characteristic curve of the flexible optoelectronic dual-control memristor under no illumination conditions and the schematic diagram of the test circuit are shown. As can be seen from Figure 5 In (a), all bias voltages are applied to the top electrode 40, while the bottom electrode 20 is grounded. Under the positive voltage scan, the flexible optoelectronic dual-control memristor switches from the high resistance state (HRS) to the low resistance state (LRS), and the set (SET) voltage is 0.25 V. Under the negative voltage scan, the flexible optoelectronic dual-control memristor returns to the low resistance state, and the reset (RESET) voltage is -0.24 V. The I-V characteristic curve of the flexible optoelectronic dual-control memristor under ultraviolet illumination is as Figure 5 shown in (b). Compared with the I-V characteristic curve of the flexible optoelectronic dual-control memristor under no illumination conditions, the SET voltage and RESET voltage of the flexible optoelectronic dual-control memristor under ultraviolet illumination are significantly reduced to 0.19 V and -0.2 V respectively; compared with the I-V characteristic curve of the flexible optoelectronic dual-control memristor under no illumination conditions, the operating voltage of the flexible optoelectronic dual-control memristor under ultraviolet illumination is lower.

[0050] Figure 5 (c) and (d) in show the fatigue characteristics and retention characteristics of the flexible optoelectronic dual-control memristor with and without ultraviolet illumination respectively. From Figure 5As can be seen from (c) in the figure, after 1000 resistance switching cycles with or without ultraviolet irradiation, the high resistance state and low resistance state of the flexible optoelectronic dual-control memristor do not show significant changes. It can be seen that the flexible optoelectronic dual-control memristor provided by the present invention has excellent storage stability under ultraviolet irradiation. In addition, when the flexible optoelectronic dual-control memristor performs resistance switching without ultraviolet irradiation, its switching ratio is only 10. Under ultraviolet irradiation, the switching ratio increases significantly to 60, which is 6 times that under non-ultraviolet irradiation conditions. As can be seen from Figure 5 in (d), the resistances of the flexible optoelectronic dual-control memristor in the LRS and HRS show excellent retention characteristics of up to 1×10 4 s under both with and without ultraviolet irradiation.

[0051] Test Example 3 The optical properties of the flexible optoelectronic dual-control memristor were studied by irradiating it with ultraviolet light in different forms, and the test results are as shown in Figure 6 . As shown in Figure 6 in (a), when the flexible optoelectronic dual-control memristor is exposed to ultraviolet light with an intensity of 4.01 mW / cm 2 and a wavelength of 375 nm for 10 seconds, the photocurrent response increases rapidly. After removing the ultraviolet light source irradiation, the photocurrent gradually decreases, which confirms that the synaptic weight of the flexible optoelectronic dual-control memristor can be improved by ultraviolet stimulation. To further verify the photoinduced plasticity induced by ultraviolet stimulation, the paired-pulse facilitation (PPF) of photoexcitation was studied, and the test results are as shown in Figure 6 in (b). Different from the PPF behavior of electrical excitation, when the flexible optoelectronic dual-control memristor is irradiated with two consecutive ultraviolet pulses with a width of 2 s and an intensity of 4.01 mW / cm 2 , the amplitude of the photocurrent response generated during the second ultraviolet pulse irradiation is larger than that during the first ultraviolet pulse irradiation. As the interval between the two consecutive ultraviolet pulses increases, the coefficient of photoexcited PPF gradually decreases and approaches 0%. Figure 6 As shown in (c), when the fixed ultraviolet irradiation time is 10 seconds and the light intensity gradually increases from 2.01 mW / cm 2 to 4.01 mW / cm 2 , the change in the photocurrent response is shown. As can be seen from Figure 6 in (c), there is a positive correlation between the intensity of ultraviolet light and the intensity of the current response of the flexible optoelectronic dual-control memristor. This result indicates that ultraviolet stimulation with different parameters will cause changes in synaptic weight, thus verifying the feasibility of photoinduced synaptic plasticity in the flexible optoelectronic dual-control memristor. To study the memristive behavior excited by ultraviolet light, continuous ultraviolet stimulation was applied to the flexible optoelectronic dual-control memristor to induce the transition of the flexible optoelectronic dual-control memristor from short-term memory to long-term memory.Figure 6 As shown in (d) therein, the photocurrent response of the flexible optoelectronic dual-control memristor under four consecutive ultraviolet stimulations with a duration of 5 seconds and an intensity of 4.01 mW / cm 2 is presented. It can be seen from Figure 6 (d) therein that after four consecutive ultraviolet stimulations, the conductivity of the flexible optoelectronic dual-control memristor increases to a certain value, which simulates the physiological behavior of the brain gradually deepening memory through subsequent stimulations. This process is similar to the brain's "learning-forgetting-relearning" process.

[0052] Comparative Example 1 Comparative Example 1 was carried out with reference to Example 1, except that the top electrode was replaced with a platinum electrode.

[0053] Test Example 4 The response characteristics of the flexible optoelectronic dual-control memristors provided by Test Example 1 and Comparative Example 1 to ultraviolet radiation are as follows. The response characteristics of the flexible optoelectronic dual-control memristor provided by Comparative Example 1 to ultraviolet radiation are as Figure 7 shown, and the response characteristics of the flexible optoelectronic dual-control memristor provided by Example 1 to ultraviolet radiation are as Figure 8 shown.

[0054] As Figure 7 shown, the flexible optoelectronic dual-control memristor provided by Comparative Example 1 has only two resistance states, namely the low-resistance state and the high-resistance state. In contrast, the I-V characteristic curve of the flexible optoelectronic dual-control memristor provided by Example 1 also changes. As can be seen from Figure 8 (a) therein, under positive and negative voltage sweeps, the current of the flexible optoelectronic dual-control memristor changes continuously and slowly. This slow regulation is an important basis for realizing bidirectional conductivity regulation in synaptic bionics. To further demonstrate the continuously adjustable electrical properties of the flexible optoelectronic dual-control memristor provided by Example 1 in the DC sweep mode, four consecutive sweeps were performed in the positive and negative voltage directions, and the test results are as Figure 8 (b) therein and Figure 8 (c) therein; among them, Figure 8 (b) therein shows the I-V characteristic curve of the flexible optoelectronic dual-control memristor after applying four consecutive positive sweep voltages. As can be seen from Figure 8 (b) therein, the current of the flexible optoelectronic dual-control memristor gradually increases with the increase in the number of sweeps. Figure 8 (c) therein shows the I-V characteristic curve of the flexible optoelectronic dual-control memristor after applying four consecutive negative sweep voltages. As can be seen from Figure 8 (c) therein, under the action of the negative sweep voltage, the current of the flexible optoelectronic dual-control memristor decreases with the increase in the number of sweeps. The above results indicate that the conductance of the flexible optoelectronic dual-control memristor can be bidirectionally regulated under DC voltage sweeps. Figure 8Among them, (d) shows the durability of the flexible optoelectronic dual-control memristor provided in Embodiment 1. From Figure 8 As can be seen from (d) in

[0055] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0056] The above-described embodiments only express several implementation manners of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the invention patent should be subject to the appended claims.

Claims

1. A flexible photoelectric dual-control memristor, characterized in that: It includes a flexible substrate, a bottom electrode, a composite functional film and a top electrode which are stacked in sequence, wherein the materials of the bottom electrode and the top electrode are both selected from silver, the composite functional film includes a stacked copper-based perovskite layer and a first hydrophobic polymer layer, the top electrode is stacked on the first hydrophobic polymer layer, and the top electrode does not completely cover the first hydrophobic polymer layer.

2. The flexible photoelectric dual-control memristor according to claim 1, characterized in that: The composite functional film also includes a second hydrophobic polymer layer, which is stacked between the copper-based perovskite layer and the bottom electrode, and the thickness ratio of the copper-based perovskite layer to the second hydrophobic polymer layer is 1:1.4-1:2.

1.

3. The flexible photoelectric dual-control memristor according to claim 1, characterized in that: The copper-based perovskite layer is selected from a (C6H5CH2NH3)2CuBr4 layer, a (CH3NH3)CuBr3 layer or a (CH(NH2)2)2CuI4 layer.

4. The flexible photoelectric dual-control memristor according to claim 1, characterized in that: The thickness ratio of the copper-based perovskite layer to the first hydrophobic polymer layer is 1:1.4-1:2.

1.

5. The flexible photoelectric dual-control memristor according to any one of claims 1 to 4, characterized in that: The thickness of the copper-based perovskite layer is less than or equal to 50 nm.

6. The flexible photoelectric dual-control memristor according to any one of claims 1 to 4, characterized in that: The flexible photoelectric dual-control memristor satisfies at least one of the following conditions: (1) The flexible substrate is selected from a flexible mica substrate, a polyimide substrate or a polyethylene terephthalate substrate; (2) the first hydrophobic polymer layer is selected from a polymethyl methacrylate layer, a polyparaxylene layer or a polyurethane layer; (3) The thickness of the top electrode is 90nm-110nm; (4) The thickness of the bottom electrode is 90nm-110nm.

7. A method for preparing a flexible photoelectric dual-control memristor according to any one of claims 1 to 6, characterized in that: The following steps are involved: Forming a bottom electrode on the surface of the flexible substrate, wherein the material of the bottom electrode is selected from silver; Firstly forming a copper-based perovskite layer on the surface of the bottom electrode, and then forming a first hydrophobic polymer layer on the surface of the copper-based perovskite layer away from the bottom electrode, wherein the copper-based perovskite layer and the first hydrophobic polymer layer form a composite functional film; and A top electrode is formed on the surface of the composite functional film, and the material of the top electrode is selected from silver, so as to obtain a flexible photoelectric dual-control memristor.

8. The method for preparing a flexible photoelectric dual-control memristor according to claim 7, characterized in that: When the copper-based perovskite layer is selected from a (C6H5CH2NH3)2CuBr4 layer, the step of forming the copper-based perovskite layer on the surface of the bottom electrode comprises: Dissolving C6H5CH2NH3Br and CuBr2 in a solvent to obtain a precursor solution; The precursor solution is formed on the surface of the bottom electrode, and a copper-based perovskite layer is formed after heating and annealing.

9. The method for preparing a flexible photoelectric dual-control memristor according to claim 8, characterized in that: In the precursor solution, the molar ratio of the C6H5CH2NH3Br to the CuBr2 is 1.8:1-2.2:1, and the mass fraction of the C6H5CH2NH3Br is 60%-68%; And / or, the heating annealing temperature is 70° C.-80° C., and the time is 30 min-50 min.

10. Application of the copper-based perovskite flexible photoelectric dual-control memristor according to any one of claims 1 to 6 in a neuromorphic circuit system.

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