An artificial synapse device with color / electric dual weight regulation

Abstract

The application discloses a kind of artificial synapse devices with color / electric dual weight regulation.The composition of the device includes: the surface edge of substrate, source electrode and drain electrode are respectively distributed with interval, and the surface of substrate between source electrode and drain electrode is covered with nanowire film;Nafion film and ion glue are sequentially covered on nanowire film.The device obtained by the application can realize the dual regulation of color weight and conductance weight under electric stimulation, and make the two weights have extremely short synaptic plasticity, and after removing stimulation for only 1 second, excitatory chroma is completely reduced to 0, and residual excitatory post-synaptic current is reduced to 1 / 3000 of initial value.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electronic devices, and in particular to a preparation method of an artificial synapse device with color / electric dual weight regulation. BACKGROUND

[0002] The computing system of the human brain mode will become an important direction of future information technology development, which will be possible to surpass the binary computing system used in the past von Neumann type memory. And building this system needs millions of neural bionic electronic devices to form a neural network. Therefore, simulating a large number of neural synapses becomes a crucial step to build artificial neural networks, and is an important foundation for the development of neuro-morphological technology and the realization of artificial brain. In the central nervous system, synapses connect neurons into a network and are responsible for signal transmission. The reconfiguration of synaptic weight is the most basic function of brain learning and memory.

[0003] Recently, artificial synapse devices exhibit similar functions and behaviors to neural synapses, which can add up the received electrical pulse signals and conduct, and have very promising prospects. However, the regulation of electrical conductance weight is the only form of synaptic weight update for these artificial synapse devices. Compared with real biological nerves, the synaptic weight simulated by a single electrical conductance weight contains insufficient information. It is a difficult point to develop more types of output information (such as color information) as a supplement to synaptic weight. In addition, due to the complexity and uncertainty of the doping and dedoping of various ions under electrical pulse stimulation, the relaxation time limit of synaptic weight update of artificial synapse devices is ambiguous, which will cause information aliasing or loss when processing time sequence signals.

[0004] In the prior art, the device structure of the document "Tunable Synaptic Plasticity in Crystallized Conjugated Polymer Nanowire Artificial Synapses" (doi: 10.1002 / aisy.201900176, hereinafter referred to as document 1) is composed of a SiO2 substrate, a P3HT nanowire film, Au (source / drain) and [PVDF-HFP][EMIM-TFSI] ionic gel (gate), and the P3HT material is used as a P-type conductive channel to realize the regulation of the weight of the electric conductance under the action of negative pulse electrical stimulation; 1) However, due to the design defects of the non-transparent substrate material and the position of the Au source / drain electrode (the Au source / drain electrode is located between the P3HT nanowire film and the ionic gel, which blocks the injection of protons from the ionic gel to the P3HT nanowire film, and the color change of the P3HT nanowire film is hindered), the device can only observe the change of the electric conductance under the action of electrical stimulation, and the color change cannot be observed near the Au source / drain electrode; 2) In addition, since the P3HT nanowire film channel is in direct contact with the ionic gel, all ions in the ionic gel will be injected into the P3HT channel under the action of electrical stimulation and will be captured for a long time, so that the ions cannot return to the initial position in a short time after the stimulation is removed, thereby causing the electric conductance of the device to be unable to quickly recover, and the residual excitatory postsynaptic current is still greater than 40% of the initial value after the stimulation is removed for 1 minute (document 1 Figure 4 )。 SUMMARY

[0005] The purpose of the present application is to provide an artificial synapse device with color / electric dual weight regulation to solve the problems existing in the prior art artificial synapse device. The device inserts a Nafion film with a film thickness of 5-10 nm between the P3HT nanowire film and the [PVDF-HFP][EMIM-TFSI] ionic gel, and the Au source / drain electrode is located below the P3HT nanowire film and is completely covered. The device obtained by the present application can simultaneously realize the dual regulation of the color weight and the electric conductance weight under the action of electrical stimulation, and both of the two weights have extremely short synaptic plasticity, and the residual excitatory chroma is completely reduced to 0 and the residual excitatory postsynaptic current is reduced to 1 / 3000 of the initial value after the stimulation is removed for only 1 second.

[0006] The technical scheme of the present application is as follows:

[0007] An artificial synapse device with color / electric dual weight regulation, the composition of the device comprises: the surface edge of the substrate is separately distributed with a source electrode and a drain electrode, and the source electrode, the drain electrode and the surface of the substrate between the two are covered with a nanowire film; the nanowire film is sequentially covered with a Nafion film and an ionic gel;

[0008] The material of the substrate is a transparent substrate such as PEN or PET;

[0009] The material of the source electrode and the drain electrode is gold or copper, and the thickness is 30-60 nm.

[0010] The material of the nanowire film is P3HT, and the thickness is 10-20 nm.

[0011] The thickness of the Nafion film is 5-10 nm.

[0012] The material of the ionic gel is [PVDF-HFP][EMIM-TFSI], and the thickness is 5-20 μm.

[0013] The preparation method of the artificial synapse device with color / electricity dual-weight regulation comprises the following steps:

[0014] Step 1: evaporating a source electrode and a drain electrode on both ends of the surface of a substrate;

[0015] Step 2: preparing a P3HT nanowire film:

[0016] The P3HT nanowire solution is spin-coated on the substrate with the evaporated source electrode and drain electrode at a rotation speed of 2000-4000 rpm / min for 25-40 s, and then annealed at 110-130 °C under a nitrogen atmosphere for 10-60 min to obtain the P3HT nanowire film.

[0017] The concentration of the P3HT solution is 1-5 mg / mL, and the solvents are dichloromethane and chlorobenzene with a volume ratio of 1:1.

[0018] The P3HT solution is heated at 50-70 °C for 1-3 h and then slowly cooled to room temperature to form the P3HT nanowire solution.

[0019] Before spin-coating, the substrate with the evaporated source electrode and drain electrode obtained in the above step is preheated at 110-130 °C for 10-120 min.

[0020] Step 3: preparing a Nafion film on the P3HT nanowire film:

[0021] The Nafion solution is spin-coated on the P3HT nanowire film at a rotation speed of 2000-4000 rpm / min for 20-40 s to obtain the Nafion film.

[0022] The concentration of the Nafion solution is 0.5-1 wt%, and the solvents are water and ethanol with a volume ratio of 1:1.

[0023] Step 4: Covering [PVDF-HFP][EMIM-TFSI] ionogel on Nafion film:

[0024] The artificial synapse device is prepared by covering 1-2 mm thick ionogel on the Nafion film.

[0025] The artificial synapse device with color / electric dual weight regulation can simultaneously increase the color weight and the conductance weight as two different excitatory synaptic weights under negative electric stimulation, and can simultaneously reduce the two different excitatory synaptic weights after the negative electric stimulation is removed.

[0026] Specifically, when an electric pulse stimulation with a duration of 0-1.5 s and an amplitude of 0--4 V is applied, the excitatory gray color gain can reach 5-28, and the excitatory postsynaptic current gain can reach-4.7 mA at the highest; after the stimulation is removed for only 1 s, the residual excitatory gray color weight can be completely reduced from 5-28 to 0, and the residual excitatory postsynaptic current can be reduced from-4.7 mA to-1.5 mu A, which is 1 / 3000 of the initial value.

[0027] The substantial features of the present application are:

[0028] All the devices reported in the previous literatures and patents (including the most similar document 1) can only observe the change of conductance under the action of electric stimulation, and the synaptic weight simulated by the single conductance weight contains insufficient information. Moreover, the recovery time of the conductance weight is long. For example, in document 1, after the stimulation is removed, the conductance of the device cannot be quickly recovered, and the residual excitatory postsynaptic current is still greater than 40% of the initial value after the stimulation is removed for 1 minute (document 1, Figure 4 f), the reason is that the Au source-drain electrode is above the P3HT nanowire film, which blocks the discoloring area of the P3HT nanowire film and cannot be observed, and since the P3HT nanowire film is directly in contact with the ionogel, a large amount of TFSI anions in the ionogel will be captured by the P3HT interface state, and when the negative electric pulse signal is removed, the captured TFSI anions cannot be doped in a short time, and the conductance weight cannot be quickly recovered.

[0029] The present application uses the structure that the Au source-drain electrode is below the P3HT nanowire film and a layer of Nafion film is inserted between the P3HT nanowire film and the ionogel, and for the first time, the device can simultaneously observe the changes of conductance and color under the action of electric stimulation. The color can serve as a second additional synaptic weight, greatly increasing the signal amount of the output weight. In addition, the device can simultaneously realize the double regulation and quick reset of the two types of weights, and after the stimulation is removed for only 1 s, the residual excitatory color is completely reduced to 0, and the residual excitatory postsynaptic current is reduced to 1 / 3000 of the initial value, which has ultra-short-term synaptic plasticity.

[0030] The beneficial effects of the present application are:

[0031] The present application designs an artificial synapse device with color / electric dual weight regulation. Through the color and electrical characterization of the designed artificial synapse device, it is proved that the device obtained by the experiment can realize the dual regulation of color weight and conductance weight under electrical stimulation, and both weights have extremely short synaptic plasticity. In this experiment, a PEN transparent substrate is selected, and the Au source and drain electrodes are below and completely covered by the P3HT nanowire film, which ensures that the color weight change of the P3HT nanowire film near the source electrode can be observed. The important reason for selecting P3HT material as the conductive channel is that the color change and fading can be realized by proton doping and dedoping, thereby realizing the stable regulation of the color weight. A low-dimensional P3HT nanowire film with a thickness of less than 20 nm is prepared by a low-temperature solvent process, which ensures the efficient transmission of hole carriers in the P3HT channel, thereby realizing efficient regulation of the conductance weight. A Nafion film with a film thickness of 5-10 nm is inserted between the P3HT nanowire film and the [PVDF-HFP][EMIM-TFSI] ionic gel. Under the action of negative voltage to the Au drain electrode, the hydrophilic and positively charged protons in the ionic gel will accumulate in the P3HT nanowire film near the Au drain electrode through the Nafion film, while the hydrophobic EMIM cation and TFSI anion in the ionic gel cannot pass through the Nafion film. The Nafion film is the key to realizing that the device has extremely short synaptic plasticity for both color / electric dual weight.

[0032] The color weight regulation mechanism is that when a negative electrical pulse signal acts on the ionic gel layer, the protons accumulated near the drain electrode diffuse to the P3HT nanowire film near the source electrode. This doping process causes the color weight of the P3HT nanowire film near the source electrode to change. When the negative electrical pulse signal ends, the protons near the source electrode can return to the drain electrode in a very short time. This dedoping process restores the color weight of the P3HT nanowire film near the source electrode.

[0033] The conductance weight regulation mechanism is that when a negative electrical pulse signal acts on the ionic gel layer, the nerve impulse generated by the simulation of the presynaptic neuron is transmitted in the form of action potential and reaches the presynaptic membrane through the branching of the axon. The TFSI anions in the ionic gel accumulate at the ionic gel / Nafion film interface, inducing the lower p-type P3HT nanowire film to produce more holes, and the conductance weight at the P3HT channel is enhanced. When the negative electrical pulse signal ends, the TFSI anions accumulated at the ionic gel / Nafion film interface can return to the original position in a very short time, and the conductance weight at the P3HT channel is restored.

[0034] If the device is not inserted into the nafion film, a large number of TFSI anions in the ion gel will be captured by the P3HT interface state, and after the negative pulse signal ends, this part of the captured TFSI anions cannot be doped in a short time, and the conductance weight cannot quickly recover; the captured TFSI anions also affect the built-in electric field of the ion gel / P3HT double electric layer, and the proton return process to the drain is blocked, and the color weight cannot quickly recover.

[0035] The present patent can achieve: 1) The device can not only observe the change of conductance under the action of electrical stimulation, but also observe the change of color; 2) After the stimulation ends, the conductance and color of the device can quickly recover, and the residual excitatory color is completely reduced to 0 after the stimulation is removed for only 1 second, and the residual excitatory postsynaptic current is reduced to 1 / 3000 of the initial value. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 It is a structural schematic diagram of an artificial synapse device with color / electric dual weight regulation;

[0037] Figure 2 It is an excitatory gray scale color curve of an artificial synapse device with color / electric dual weight regulation under electrical pulse stimulation;

[0038] Figure 3 It is an excitatory gray scale color degradation curve of an artificial synapse device with color / electric dual weight regulation after the electrical pulse stimulation is removed;

[0039] Figure 4 It is an excitatory postsynaptic current curve of an artificial synapse device with color / electric dual weight regulation under electrical pulse stimulation;

[0040] Figure 5 It is an excitatory postsynaptic current degradation curve of an artificial synapse device with color / electric dual weight regulation after the electrical pulse stimulation is removed; DETAILED DESCRIPTION

[0041] The specific embodiments of the present application will be further described in detail below in combination with the drawings.

[0042] As Figure 1As shown, the application provides an artificial synapse device with color / electric dual weight regulation. In the experiment, a PEN transparent substrate is selected, and the Au source and drain electrodes are located below and completely covered by the P3HT nanowire film, so that the color weight change of the P3HT nanowire film near the source electrode can be observed. The important reason for selecting P3HT material as the conductive channel is that the color change and fading can be realized by proton doping and dedoping, so as to realize the stable regulation of the color weight. A low-dimensional P3HT nanowire film with a thickness of less than 20 nm is prepared by a low-temperature solvent process, so that the hole carriers can be efficiently transmitted in the P3HT channel, thereby realizing efficient regulation of the electric conductance weight. A Nafion film with a film thickness of 5-10 nm is inserted between the P3HT nanowire film and the [PVDF-HFP][EMIM-TFSI] ionic gel. Under the action of negative voltage to the Au drain electrode, the hydrophilic and positively charged protons in the ionic gel can accumulate in the P3HT nanowire film near the Au drain electrode through the Nafion film, while the hydrophobic EMIM cations and TFSI anions in the ionic gel cannot pass through the Nafion film. The Nafion film is the key to realizing that the device has extremely short synaptic plasticity in color / electric dual weight.

[0043] The color weight regulation mechanism is that when a negative electric pulse signal acts on the ionic gel layer, the protons accumulated near the drain electrode diffuse to the P3HT nanowire film near the source electrode, and the doping process causes the color weight of the P3HT nanowire film near the source electrode to change; after the negative electric pulse signal ends, the protons near the source electrode can return to the drain electrode in a very short time, and the dedoping process restores the color weight of the P3HT nanowire film near the source electrode.

[0044] The conductance weight regulation mechanism is that when a negative electric pulse signal acts on the ionic gel layer, the nerve impulse generated by the presynaptic neuron is transmitted in the form of action potential and reaches the presynaptic membrane through the branching of the axon, and the TFSI anions in the ionic gel accumulate at the ionic gel / Nafion film interface, inducing the lower p-type P3HT nanowire film to generate more holes, and the conductance weight of the P3HT channel is enhanced; after the negative electric pulse signal ends, the TFSI anions accumulated at the ionic gel / Nafion film interface can return to the original position in a very short time, and the conductance weight of the P3HT channel is restored.

[0045] Example 1

[0046] The application designs an artificial synapse device with color / electric dual weight regulation, comprising the following steps:

[0047] Step 1, Au source-drain electrode was deposited on the PEN transparent substrate (2 cm in length and width, 0.1 mm in thickness): a 50 μm thick mask plate was taken out and was flatly pasted on the surface of the PEN transparent substrate. The PI heat-resistant tape was cut into small pieces and was pasted on the interface between the interdigital electrode mask plate (the width of the interdigital electrode was 1500 μm, the length was 40 μm, and the interdigital distance was 40 μm) and the substrate. The mask plate was arranged on the surface of the glass flat plate with the substrate pasted on the mask plate, and was fixed with the PI heat-resistant tape. The glass plate was placed upside down in the gold evaporation equipment for physical vapor deposition to deposit 60 nm Au source-drain electrode.

[0048] Step 2, P3HT nanowire film was prepared on the Au source-drain electrode: P3HT was fully dissolved in the mixed solvent of dichloromethane and chlorobenzene (volume ratio 1:1) (concentration 2 mg / mL). After the P3HT solution was heated at 60°C for 2 h and slowly cooled to room temperature, a nanowire solution containing crystalline nanowires was formed. After the PEN transparent substrate with Au source-drain electrode was preheated at 120°C for 10 min, the P3HT nanowire solution was spin-coated on the substrate at a speed of 2000 rpm / min for 30 s, and was annealed in a nitrogen environment at 120°C for 10 min to obtain a P3HT nanowire film with a thickness of 15 nm.

[0049] Step 3, Nafion film was prepared on the P3HT nanowire film: Nafion was dispersed in the mixed solvent of water and ethanol (volume ratio 1:1) to obtain a 0.5 wt% Nafion solution. The Nafion solution was spin-coated on the P3HT nanowire film at a speed of 2000 rpm / min for 30 s to obtain a Nafion film with a thickness of 5 nm.

[0050] Step 4, drop-coating of [PVDF-HFP][EMIM-TFSI] ionic gel on Nafion film: after mixing the polymer PVDF-HFP (i.e. poly(vinylidene fluoride-co-hexafluoropropylene) solution and ionic liquid EMIM-TFSI (i.e. 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide salt) solution, stirring for 5h, [PVDF-HFP][EMIM-TFSI] ionic gel solution was obtained (wherein the mass ratio of polymer PVDF-HFP to ionic liquid EMIM-TFSI was 1:4; the solvents were both acetone; 0.25g polymer PVDF-HFP was dissolved in 1g acetone, and 1g ionic liquid EMIM-TFSI was dissolved in 1g acetone). 800μL of ionic gel solution was dropped on a 2cm×2cm square glass mold, and then transferred into a vacuum oven with a pressure of 6Pa and a temperature of 60℃ for 12h. After drying, the ionic gel was peeled off from the glass mold, and an ionic gel with a thickness of 2mm was obtained. The peeled [PVDF-HFP][EMIM-TFSI] ionic gel was covered on the Nafion film, and the prepared device was placed in a nitrogen glove box for testing.

[0051] The artificial synapse device obtained above consists of a transparent substrate, Au (source / drain), P3HT nanowire film, Nafion film and [PVDF-HFP][EMIM-TFSI] ionic gel (gate). The synapse device can realize the dual regulation of color weight and conductance weight under electrical stimulation, and both weights have extremely short synaptic plasticity, which can simulate the different types of synaptic weight change processes when the presynaptic membrane releases neurotransmitters in biology.

[0052] In order to embody the beneficial effects, the following tests were carried out:

[0053] As shown in Figure 2 Fig. 6, under the condition that the source electrode is grounded, the drain electrode voltage is -1V, and an electrical pulse with an intensity of -4V and a duration of 1.5s is applied, the excitatory gray chromaticity change of the color weight sampling area of the source electrode. The negative voltage acts on the Au drain electrode, and the hydrophilic and positively charged protons in the ionic gel accumulate near the P3HT nanowire film of the Au drain electrode through the Nafion film, while the hydrophobic EMIM cations and TFSI anions in the ionic gel cannot pass through the Nafion film. The negative pulse signal acts on the ionic gel layer, and the protons accumulated near the drain electrode diffuse to the P3HT nanowire film near the source electrode. This doping process causes the color weight of the P3HT nanowire film near the source electrode to change. Under this test condition, the device shows obvious color weight change, and the excitatory gray chromaticity change reaches 28. Literature 1 does not report relevant data. Therefore, the artificial synapse device can effectively regulate the color weight.

[0054] As shown in Figure 3 , the residual excitatory gray color of the source color weight sampling area changes over time after a negative electrical pulse stimulus with an intensity of -4 V and a duration of 1.5 s is applied and removed. After the end of the negative electrical pulse signal, the protons near the source can return to the drain in a very short time (within 1 s), and this de-doping process restores the color weight of the P3HT nanowire film near the source. Under the test conditions, the residual excitatory gray color of the device decreases to 0 only 1 s after the stimulus is removed. Literature 1 does not report relevant data. Therefore, the artificial synapse device has very short color weight short-range plasticity.

[0055] As shown in Figure 4 , the excitatory post-synaptic current output by the drain of an artificial synapse device with dual color / conductance weight regulation under the condition of source grounding, drain voltage of -1 V, and application of an electrical pulse stimulus with an intensity of -4 V and a duration of 1.5 s. The negative voltage is applied to the Au drain, and the negative electrical pulse signal is applied to the ion gel layer, simulating the process of action potential transmission by the axon branch to the presynaptic membrane. The TFSI anions in the ion gel accumulate at the ion gel / Nafion film interface, inducing the underlying p-type P3HT nanowire film to generate more holes, and the conductance weight at the P3HT channel is enhanced. Under the test conditions, the device exhibits a significant change in conductance weight, and the excitatory post-synaptic current reaches -4.7 mA. Therefore, the artificial synapse device can effectively regulate the conductance weight.

[0056] As shown in Figure 5 , the residual excitatory post-synaptic current output by the drain of an artificial synapse device with dual color / conductance weight regulation changes over time after a negative electrical pulse stimulus with an intensity of -4 V and a duration of 1.5 s is applied and removed. After the end of the negative electrical pulse signal, the TFSI anions accumulated at the ion gel / Nafion film interface can return to the initial position in a very short time (within 1 s), and the conductance weight at the P3HT channel is restored. Under the test conditions, the residual excitatory post-synaptic current of the device decreases to 1 / 3000 of the initial value only 1 s after the stimulus is removed; Literature 1, the conductance of the device cannot quickly recover after the stimulus is removed, and the residual excitatory post-synaptic current is still greater than 40% of the initial value 1 minute after the stimulus is removed (Literature 1, Figure 4 f). Therefore, the artificial synapse device has very short conductance weight short-range plasticity.

[0057] The value range of the chroma is 0-255, wherein 0 is pure black and 255 is pure white.

[0058] Example 2

[0059] The other steps are the same as those in Example 1, except that the Nafion (1wt%) is dispersed in a mixed solvent of water and ethanol (volume ratio 1:1) instead of the Nafion (0.5wt%) being dispersed in a mixed solvent of water and ethanol (volume ratio 1:1).

[0060] Example 3

[0061] The other steps are the same as those in Example 1, except that the mass ratio of the polymer PVDF-HFP to the ionic liquid EMIM-TFSI is 1:4; the solvents are all acetone; 0.25 grams of the polymer PVDF-HFP is dissolved in 1 gram of acetone, and 1 gram of the ionic liquid EMIM-TFSI is dissolved in 1 gram of acetone, which is changed to the mass ratio of the polymer PVDF-HFP to the ionic liquid EMIM-TFSI being 1:2; the solvents are all acetone; 0.25 grams of the polymer PVDF-HFP is dissolved in 1 gram of acetone, and 0.5 grams of the ionic liquid EMIM-TFSI is dissolved in 1 gram of acetone.

[0062] It can be seen from the above examples that, in order to realize the dual regulation and rapid reset of the conductance and chroma weights of the device under the action of electrical stimulation, the following improvements are made in the present application:

[0063] 1) In document 1, a dark and opaque SiO2 substrate is selected, and the background color is too dark to observe the color weight change; in the present patent, a transparent PEN substrate is selected to ensure that the color weight change of the P3HT nanowire film near the source electrode can be observed.

[0064] 2) In document 1, the Au source and drain electrodes are above the P3HT nanowire film, which blocks the color-changing area of the P3HT nanowire film and makes it impossible to be observed; in the present patent, the Au source and drain electrodes are below the P3HT nanowire film and are completely covered, which ensures that the color weight change of the P3HT nanowire film near the source electrode can be observed.

[0065] 3) In document 1, P3HT material is selected as the conductive channel only because P3HT is a kind of hole transport material with good performance and stability, and this material can be replaced; in the present patent, P3HT material is selected as the conductive channel not only because of its good hole transport performance, but also because of the important reason that proton doping and dedoping can realize color change and fading, thereby realizing stable regulation of the color weight. Moreover, a low-dimensional P3HT nanowire film with a thickness of less than 20 nm is prepared through a low-temperature solvent process, which ensures efficient transport of hole carriers in the P3HT channel, thereby realizing efficient regulation of the conductance weight, and the output excitatory postsynaptic current is as high as -4.7 mA Figure 4). Meanwhile, the p-type organic semiconductor satisfying both the milliamperes level of postsynaptic current output and stable proton doping / de-doping induced electrochromic characteristics is only P3HT.

[0066] 4) The patent selects [PVDF-HFP][EMIM-TFSI] ionic glue, which contains protons that can cause P3HT nanowire film to change color and TFSI anions that can induce P3HT nanowire film to produce a large number of hole carriers.

[0067] 5) In document 1, no nafion layer is added, so all ions in the [PVDF-HFP][EMIM-TFSI] ionic glue will be injected into P3HT under electrical stimulation and captured for a long time, so that after the stimulus is removed, the ions cannot return to the original position in a short time, resulting in that the residual excitatory postsynaptic current is maintained at a large value for a long time; The patent inserts a 5-10 nm thick nafion film between the P3HT nanowire film and the [PVDF-HFP][EMIM-TFSI] ionic glue (if nafion is less than 5 nm, it cannot block the injection of ions, and if nafion is greater than 10 nm, it will weaken the induction of TFSI anions to P3HT channel hole carriers) only at this thickness can ensure: 1. When a negative voltage is applied to the Au drain, the hydrophilic and positively charged protons in the ionic glue will accumulate in the P3HT nanowire film near the Au drain through the nafion film, while the hydrophobic EMIM cation and TFSI anion in the ionic glue cannot pass through the nafion film; 2. When a negative stimulus is applied to the ionic glue, TFSI anions can gather at the interface between the ionic glue and nafion, and effectively induce the generation of excitatory postsynaptic current in the P3HT channel, but due to the shielding of nafion, anions cannot be injected into P3HT, so once the stimulus is removed, the ions can return to the original position in a short time, and the residual excitatory postsynaptic current decays in a very short time.

[0068] The Nafion film is suitable for a synaptic device in a transistor structure to realize color / electric dual weight regulation, and the specific mechanism is as follows: 1. The negative voltage acts on the Au drain, and the hydrophilic and positively charged protons in the ion glue can accumulate in the P3HT nanowire film close to the Au drain through the Nafion film, while the hydrophobic EMIM cation and TFSI anion in the ion glue cannot pass through the Nafion film; 2. On the basis of the negative voltage acting on the Au drain, when the negative pulse signal acts on the ion glue layer, the protons accumulated near the drain diffuse to the P3HT nanowire film near the source, and this doping process changes the color weight of the P3HT nanowire film near the source; the TFSI anion in the ion glue can accumulate at the ion glue / Nafion film interface, induce more holes in the lower p-type P3HT nanowire film, and enhance the conductance weight of the P3HT channel; 3. When the negative pulse signal ends, the protons near the source can return to the drain in a very short time, and the de-doping process restores the color weight of the P3HT nanowire film near the source; the TFSI anion accumulated at the ion glue / Nafion film interface can return to the original position in a very short time, and the conductance weight of the P3HT channel is restored.

[0069] Through the above examples and analysis, it can be concluded that the present application designs a systematic study of an artificial synaptic device with color / electric dual weight regulation. The conclusions with scientific guiding significance have regularity, which has important guiding significance for device material selection and structure design in the field. The synaptic device can realize the dual regulation of color weight and conductance weight under electrical stimulation, and make both weights have very short synaptic plasticity, which can simulate different types of synaptic weight change processes when the presynaptic membrane releases neurotransmitters in biology. Compared with the traditional artificial synapse which only has the regulation ability of conductance weight, the present application expands the diversity of artificial synaptic device weight regulation, provides a new technical route for the realization of synaptic short-range plasticity, and has wide application value in the field of neural bionic electronic devices.

[0070] The remaining matters of the present application are well-known technologies.

Claims

1. An artificial synaptic device with color / electric dual-weighted modulation, characterized in that: The device consists of: source and drain electrodes distributed at intervals on the surface edge of a substrate; nanowire thin films covering the source, drain, and the substrate surface between them; and Nafion thin films and ionomer gels sequentially covering the nanowire thin films. The thickness of the Nafion film is 5~10 nm; The artificial synaptic device with color / electricity dual weighting control can simultaneously increase color weight and electrical conductance weight as two different excitatory synaptic weights under negative electrical stimulation; and simultaneously decrease the two different excitatory synaptic weights after the negative electrical stimulation is removed. When an electrical pulse with a duration of 0–1.5 s and an amplitude of 0–-4 V is applied, the excitatory grayscale and chromaticity gain reaches 5–28, and the excitatory postsynaptic current gain reaches -4.7 mA. After the above stimulation is removed for 1 second, the excitatory grayscale and chromaticity weight drops completely from 5–28 to 0, while the residual excitatory postsynaptic current drops from -4.7 mA to -1.5 μA, which is less than 1 / 3000 of the initial value.

2. The artificial synaptic device with color / electric dual weighting as described in claim 1, characterized in that the substrate is made of a transparent substrate such as PEN or PET; The source and drain electrodes are made of the same material, gold or copper, with a thickness of 30~60 nm. The nanowire thin film is made of P3HT and has a thickness of 10~20 nm. The ionomer adhesive is made of [PVDF-HFP][EMIM-TFSI] material and has a thickness of 5~20 μm.

3. The method for fabricating an artificial synaptic device with color / electric dual-weighted modulation as described in claim 1, characterized in that the method comprises the following steps: Step 1: Deposit the source and drain electrodes at both ends of the substrate surface, respectively; Step 2: Preparation of P3HT nanowire thin films: P3HT nanowire solution was spin-coated onto the substrate with vapor-deposited active and drain electrodes at a speed of 2000~4000 rpm / min for 25~40 s, and then annealed at 110~130℃ in a nitrogen atmosphere for 10~60 min to obtain P3HT nanowire thin film. in, The concentration of P3HT solution is 1~5 mg / mL, and the solvent is dichloromethane and chlorobenzene in a volume ratio of 1:

1. Step 3: Prepare Nafion films on P3HT nanowire films: Nafion solution was spin-coated onto P3HT nanowire films at a speed of 2000~4000 rpm / min for 20~40 s to obtain Nafion films; The concentration of the Nafion solution is 0.5~1 wt%, and the solvents are water and ethanol in a volume ratio of 1:

1. Step 4: Cover the Nafion film with [PVDF-HFP] and [EMIM-TFSI] ionomer adhesives: Artificial synaptic devices are fabricated by coating Nafion films with 1-2 mm thick ionomer glue.

4. The method for fabricating an artificial synaptic device with color / electric dual-weighted modulation as described in claim 3, characterized in that: In step 2, the P3HT solution is heated at 50~70℃ for 1~3 h and then slowly cooled to room temperature to form a P3HT nanowire solution.

5. The method for fabricating an artificial synaptic device with color / electric dual-weighted modulation as described in claim 3, characterized in that: In step 2, before spin coating, the substrates for the vapor-deposited active and drain electrodes obtained in the previous step are preheated at 110~130℃ for 10~120 min.

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