An artificial synapse based on layered multi-metal oxide and its preparation method

Abstract

The application discloses a kind of artificial synapses based on layered multi-metal oxide and preparation method thereof, the artificial synapses with aluminum foil as bottom electrode, with layered multi-metal oxide Na 0.66 Mg 0.28 Mn 0.72 O2 As functional layer, with pectin composite film as solid-state electrolyte, with Au as top electrode.The artificial synapses disclosed in the application has simple structure, simple and easy-to-operate preparation method, uses green and non-toxic pectin composite film as solid-state electrolyte, has good biological compatibility, absolute short-range plasticity and high synaptic plasticity, high current response, and fast current reset speed.In the pectin composite film used as solid-state electrolyte of artificial synapse, NaCl is doped, which can further improve the current response and speed up the current reset speed.The application has wide application prospect in the fields of artificial intelligence, big data processing, pattern recognition, neural engineering and brain-computer interface.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electronic devices, and more particularly, to an artificial synapse based on layered multi-metal oxide and a preparation method thereof. BACKGROUND

[0002] The development of future information technology will focus on the computing system of the human brain mode, which is expected to surpass the traditional binary computing system based on the Von Neumann structure (also known as the Princeton structure). In order to build such a computing system of the human brain mode, it will be necessary to use millions of neural bionic electronic devices to form a neural network. Therefore, simulating such a large number of neural synapses is crucial for building an artificial neural network. The development of neuromorphic technology and the realization of artificial brains both depend on this step. Research has found that artificial synapse devices with transistor structures can exhibit similar functions and behaviors to neural synapses. These devices can perform additive processing and conduction on received electrical pulse signals, and have broad application prospects in the fields of artificial intelligence, big data processing, pattern recognition, neural engineering, and brain-computer interfaces.

[0003] At present, one of the traditional methods for manufacturing artificial synapses is to combine layered multi-metal oxide and liquid electrolyte together. When the top electrode of the artificial synapse manufactured by this manufacturing method is repeatedly stimulated by pulses, ions will migrate from the liquid electrolyte to the layered multi-metal oxide and be captured by the layered multi-metal oxide. However, when the stimulation stops, the excited excitatory postsynaptic current cannot quickly recover to below 10% of the initial value. Usually, the reset time is much longer than 10 seconds. Although this solution has high synaptic plasticity, it is not suitable for processing time-frequency signals because it lacks short-term plasticity.

[0004] Therefore, there is an urgent need in the art to develop an artificial synapse that has both absolute short-term plasticity and high synaptic plasticity. SUMMARY

[0005] The purpose of the present application is to overcome the shortcomings of the prior art and provide an artificial synapse based on layered multi-metal oxide and a preparation method thereof.

[0006] The first purpose of the present application is to provide a preparation method of a pectin composite film of a solid-state electrolyte for an artificial synapse.

[0007] The second purpose of the present application is to provide an artificial synapse based on layered multi-metal oxide.

[0008] The third purpose of the present application is to provide an application of an artificial synapse based on layered multi-metal oxide.

[0009] In order to achieve the above purposes, the present application is implemented by the following technical solutions:

[0010] A preparation method of a pectin composite film of a solid electrolyte for artificial synapse, comprising the following steps:

[0011] S11. Dissolve the water-soluble pectin and water in glycerol after mixing them uniformly to obtain a mixed solution, wherein the ratio of the water-soluble pectin, water and glycerol is 40-70 mg of water-soluble pectin: 2-3.5 ml of water: 100-200 μl of glycerol;

[0012] S12. Inject the mixed solution prepared in step S11 into a mold, drop 40-70 μl of the mixed solution per square centimeter of the mold, and dry at 50-70°C for 1-4 h to obtain a pectin composite film.

[0013] Preferably, in step S11, the water-soluble pectin has a molecular weight of not more than 150.

[0014] Preferably, in step S11, the water-soluble pectin and water are mixed uniformly, and then glycerol is added, and the mixed solution is obtained after heating and stirring until complete dissolution.

[0015] More preferably, in step S11, the heating temperature is 20-70°C.

[0016] More preferably, in step S11, the stirring speed is 500-1000 rpm.

[0017] More preferably, in step S11, the stirring time is 20-40 h.

[0018] Most preferably, in step S11, the mixed solution is obtained by stirring at 600 rpm for 24 h at 70°C after adding glycerol.

[0019] Preferably, in step S11, the ratio of the water-soluble pectin, water and glycerol is 60 mg of water-soluble pectin: 3 ml of water: 150 μl of glycerol.

[0020] Preferably, in step S11, the water-soluble pectin, water and water-soluble sodium salt are mixed uniformly, and then glycerol is added, and the mixed solution is obtained after mixing, wherein the mass fraction of the water-soluble sodium salt in the mixed solution is 0.4-0.6%.

[0021] More preferably, the water-soluble sodium salt is NaCl.

[0022] Further more preferably, the NaCl is NaCl powder.

[0023] Most preferably, in step S11, the ratio of the water-soluble pectin, water, NaCl and glycerol is 60 mg of water-soluble pectin: 3 ml of water: 15 mg of NaCl: 150 μl of glycerol.

[0024] More preferably, in step S11, the water-soluble pectin, water and water-soluble sodium salt are mixed uniformly at 20-70°C, and then glycerol is added.

[0025] Most preferably, in step S11, the water-soluble pectin, water and NaCl powder are mixed uniformly at 70°C.

[0026] Preferably, in step S12, the mixture is dried at 60°C for 1-3.5h to obtain the pectin composite film.

[0027] The pectin composite film prepared by the method should also be within the protection scope of the present application.

[0028] Preferably, the pectin composite film is one containing 0.4-0.6% water-soluble sodium salt by mass fraction.

[0029] More preferably, the water-soluble sodium salt is NaCl.

[0030] A layered multi-metal oxide-based artificial synapse, comprising, from bottom to top, a bottom electrode, a functional layer, a solid-state electrolyte layer and a top electrode layer, wherein the functional layer is a layered multi-metal oxide, and the solid-state electrolyte layer is the pectin composite film.

[0031] Preferably, the material of the bottom electrode is an electrically good conductor.

[0032] More preferably, the bottom electrode is one metal or a composite of two or more metals selected from copper, aluminum, gold and silver, or indium tin oxide or zinc aluminum oxide.

[0033] Further more preferably, the material of the bottom electrode is aluminum foil or copper foil.

[0034] Most preferably, the material of the bottom electrode is aluminum foil.

[0035] Further most preferably, the bottom electrode is double-sided carbon-coated aluminum foil.

[0036] Preferably, the thickness of the functional layer is 5-10μm.

[0037] Preferably, the layered multi-metal oxide has the general formula Na x TMO2.

[0038] More preferably, the layered multi-metal oxide has the general formula Na x TMO2, wherein 0.5≦x≦0.8.

[0039] Most preferably, the layered multi-metal oxide is Na 0.66 Mg 0.28 Mn 0.72 O2.

[0040] Preferably, the solid electrolyte layer is the pectin composite membrane containing 0.4-0.6% by mass of water-soluble sodium salt.

[0041] More preferably, the water-soluble sodium salt is NaCl.

[0042] Preferably, the solid electrolyte layer has a thickness of 5 to 30 μm.

[0043] More preferably, the solid electrolyte layer has a thickness of 7 to 30 μm.

[0044] Most preferably, the solid electrolyte layer has a thickness of 15 μm.

[0045] Preferably, the top electrode layer contains a plurality of top electrodes, and the top electrodes are arranged in an array on the solid electrolyte layer.

[0046] More preferably, the top electrode has a thickness of 30 to 80 nm.

[0047] Most preferably, the top electrode has a thickness of 60 nm.

[0048] Preferably, the top electrode layer is obtained by evaporating a good electrical conductor onto the solid electrolyte layer using a thermal evaporation method.

[0049] More preferably, the top electrode is one metal selected from copper, aluminum, gold, and silver, or a composite metal of two or more metals, or indium tin oxide or zinc aluminum oxide.

[0050] Most preferably, the top electrode is gold or copper.

[0051] More preferably, the top electrode is gold.

[0052] The application of the artificial synapse based on layered multi-metal oxides in large-scale artificial synapse array integration and system design should also be within the scope of protection of the present invention.

[0053] The method for preparing the artificial synapse based on layered multi-metal oxides comprises the following steps:

[0054] S21. will meet Na x Mixing the mixed metal oxide powder in a TMO2 ratio with a polymer adhesive to obtain a slurry, placing the slurry on the bottom electrode, applying it evenly, and then drying it to a constant weight to obtain a bottom electrode covered with a functional layer of uniform thickness;

[0055] S22. Laminating the pectin composite film onto the functional layer on the bottom electrode after drying in step S21, and thermally evaporating the top electrode on the pectin composite film to obtain an artificial synapse based on layered multi-metal oxides.

[0056] Preferably, in step S21, the x The preparation method of mixed metal oxide powder with TMO2 ratio is as follows:

[0057] According to Na x The metal oxide raw materials are weighed according to the stoichiometric ratio of TMO2, one of the metal oxide raw materials needs to be weighed in excess, the weighed metal oxide raw materials are mixed evenly, and then ground to obtain a ground material body;

[0058] The ground material body is pressed into tablets and then sintered under the sintering conditions of 750-900° C. for 12-20 hours at a heating rate of 5-20° C. / min to obtain a sintered material body;

[0059] The sintered material was ground for 30 to 40 minutes to obtain a x Mixed metal oxide powder with TMO2 ratio.

[0060] More preferably, one of the metal oxide raw materials is weighed in an excess of 3 to 8%.

[0061] Most preferably, one of the metal oxide raw materials is weighed in a 5% excess.

[0062] Preferably, in step S21, the polymer adhesive is an N-methylpyrrolidone solution containing polyvinylidene fluoride, polyacrylic acid, sodium polyacrylate, sodium carboxymethyl cellulose or polyimide.

[0063] More preferably, in step S21, the polymer adhesive is an N-methylpyrrolidone solution containing 2-5% polyvinylidene fluoride.

[0064] Most preferably, in step S21, the polymer adhesive is an N-methylpyrrolidone solution containing 4% polyvinylidene fluoride.

[0065] Specifically, the polyvinylidene fluoride is polyvinylidene fluoride with a molecular weight of 1 million.

[0066] Preferably, in step S21, the slurry humidity is controlled to be no more than 10% to 20%.

[0067] More preferably, in step S21, the slurry humidity is controlled not to exceed 15%.

[0068] Preferably, in step S21, the drying conditions are: 70-100° C., 30-60 min.

[0069] More preferably, in step S21, the drying condition is: 80°C.

[0070] Preferably, in step S21 , the slurry is placed on the bottom electrode, evenly coated using a 5-10 μm coater, and then dried to a constant weight.

[0071] Preferably, in step S22, the top electrode is thermally evaporated on the pectin composite film in an array shape.

[0072] More preferably, the array shape is a dot array.

[0073] Further more preferably, the radius of the top electrode is 1 to 10,000 μm, and the center distance between the top electrodes is 20 to 10,000 μm.

[0074] As a reference for a specific implementation, the radius of the top electrode is 250 μm, and the center distance between the top electrodes is 1500 μm.

[0075] Preferably, in step S22, the pectin composite film is the pectin composite film containing 0.4-0.6% by mass of water-soluble sodium salt.

[0076] More preferably, the water-soluble sodium salt is NaCl.

[0077] Compared with the prior art, the present invention has the following beneficial effects:

[0078] (1) In the preparation process of the artificial synapse based on layered multi-metal oxide disclosed in the present invention, the traditional liquid electrolyte is replaced by a degradable solid electrolyte (pectin composite membrane), which not only helps to protect the environment, but also can be further doped with NaCl. The NaCl-doped pectin composite membrane is used as the solid electrolyte layer of the artificial synapse. In addition to the H + In addition to ions, doped Na + Ion energy with Na metal sites x The TMO2 layered multi-metal oxide is compatible, thereby further enhancing synaptic plasticity and improving the current responsiveness of the prepared artificial synapse. In addition, the inventors further discovered that by using the pectin composite membrane as a solid electrolyte, the migrating cations can only be captured by the shallow traps on the surface of the multi-metal layered multi-metal oxide, ensuring rapid dedoping. Therefore, after the stimulus disappears, the current can be quickly reset, and the reset time does not vary with the doping of Na. + The number of ions increases and the length increases, so the artificial synapse prepared can quickly respond and adapt to different input signals;

[0079] (2) The artificial synapse based on layered multi-metal oxides proposed in the present invention can enhance the release of excitatory neurotransmitters after continuous application of positive pulses, maintain its transmission efficiency under continuous stimulation, and its transmission efficiency and intensity can change to a large extent when stimulated, possessing absolute short-range plasticity and high synaptic plasticity;

[0080] (3) The artificial synapse disclosed by the application uses green and non-toxic pectin as a solid-state electrolyte, and is compatible with organisms. The artificial synapse has a simple structure, a simple and easy-to-implement preparation method and low cost, is very suitable for large-scale application, and has very important significance for promoting the wide application of artificial synapses in the fields of artificial intelligence, big data processing, pattern recognition, neural engineering and brain-computer interface. BRIEF DESCRIPTION OF DRAWINGS

[0081] Figure 1 It is a schematic diagram of a structure of an artificial synapse based on layered multi-element metal oxides.

[0082] Figure 2 It is an excitatory postsynaptic current graph of the artificial synapse prepared in Example 1 under the stimulation of a single 0.05s positive pulse.

[0083] Figure 3 It is an excitatory postsynaptic current graph of the artificial synapse prepared in Example 2 under the stimulation of a single 0.05s positive pulse.

[0084] Figure 4 It is an excitatory postsynaptic current graph of the artificial synapse prepared in Example 1 under the stimulation of 50 0.05s positive pulses.

[0085] Figure 5 It is a postsynaptic current decay graph of the artificial synapse prepared in Example 1 after the stimulation of 50 0.05s positive pulses.

[0086] Figure 6 It is an excitatory postsynaptic current graph of the artificial synapse prepared in Example 2 under the stimulation of 50 0.05s positive pulses.

[0087] Figure 7 It is a postsynaptic current decay graph of the artificial synapse prepared in Example 2 after the stimulation of 50 0.05s positive pulses.

[0088] Figure 8 It is an excitatory postsynaptic current graph of the artificial synapse prepared in Example 1 under the stimulation of a Morse code system electric pulse signal representing four letters A, B, C and D. DETAILED DESCRIPTION

[0089] The application will be further described in detail below in combination with the drawings and specific examples in the specification. The examples are only used to explain the application and are not used to limit the scope of the application. The test methods used in the following examples are conventional methods unless otherwise specified. The materials, reagents and the like used in the following examples are commercially available reagents and materials unless otherwise specified.

[0090] Example 1 An artificial synapse based on layered multi-metal oxides and its preparation method

[0091] An artificial synapse based on layered multi-metal oxides, the structural diagram of which is shown in the figure Figure 1 As shown, it uses aluminum foil as the bottom electrode and multi-metal oxide Na 0.66 Mg 0.28 Mn 0.72 O2 was used as the functional layer, NaCl-doped pectin composite film was used as the solid electrolyte layer, and gold (Au) was used as the top electrode.

[0092] The preparation method of the above-mentioned artificial synapse based on layered multi-metal oxides:

[0093] S1. Customize a stainless steel mask with holes of 500 μm in diameter and a distance of 1500 μm between the centers of the holes.

[0094] S2. Configure multi-metal oxide Na 0.66 Mg 0.28 Mn 0.72 O2 material:

[0095] According to Na 0.66 Mg 0.28 Mn 0.72 To ensure the complete reaction, the molar amount of Na2CO3 is 5% higher than the theoretical value. The weighed materials are placed in an agate mortar and roughly mixed, and ground for 1 hour to obtain a ground metal oxide material. Specifically, the molar ratio of Na2CO3, MgO and Mn2O3 in the weighed materials is 346.5:28:36;

[0096] S3. Tableting and firing:

[0097] The ground metal oxide material obtained in step S2 is pressed into a tablet shape, then placed in an alumina crucible and sintered in a muffle furnace. The sintering reaction conditions are: 800° C., 15 h, and a heating rate of 5° C. / min to obtain a sintered material.

[0098] S4. Grinding:

[0099] The sintered material obtained in step S3 was placed in an agate mortar and ground for 40 min to obtain the ground Na 0.66 Mg 0.28 Mn 0.72 O2 material;

[0100] S5. Adhesive:

[0101] Polyvinylidene fluoride (PVDF) with a molecular weight of 1 million was dissolved in N-methylpyrrolidone (NMP) at a concentration of 4% by mass and stirred at 40°C for 24 hours to obtain an adhesive;

[0102] S6. Preparation of functional layer:

[0103] Take 0.07g of the ground Na obtained in step S4 0.66 Mg 0.28 Mn 0.72 The O2 material and about 250 μL of the adhesive prepared in step S5 were placed in an agate mortar and evenly mixed to prepare a slurry. The slurry humidity was controlled to be no more than 15%. The slurry was evenly coated on one side of a double-sided carbon-coated aluminum foil using a 10 μm applicator and dried at 80°C to constant weight to prepare a carbon-coated aluminum foil covered with a functional layer. The functional layer had a thickness of 10 μm.

[0104] S7. Preparation of NaCl-doped pectin composite film:

[0105] 60 mg of water-soluble pectin with a molecular weight not higher than 150 and 15 mg of NaCl powder were dissolved in 3 ml of water and stirred at 70°C and 600 rpm for 40 min to obtain a solution. 150 μL of glycerol was added dropwise to the solution to obtain a pectin solution containing glycerol and NaCl. The pectin solution containing glycerol and NaCl was stirred at 70°C and 600 rpm for 24 h and then completely injected into an area of ​​55 cm 2 The mixture was placed in a plastic surface dish and dried at 60℃ for 2h to prepare a NaCl-doped pectin composite film with a thickness of 15μm.

[0106] S8. Evaporation electrode:

[0107] Utilizing the adhesive properties of the NaCl-doped pectin composite film prepared in step S7, the NaCl-doped pectin composite film was directly bonded to the functional layer of the carbon-coated aluminum foil covering the functional layer prepared in step S6. The mask prepared in step S1 was bonded to the surface of the NaCl-doped pectin composite film, and Au with a thickness of 60 nm was thermally evaporated as the top electrode to prepare an artificial synapse based on a layered multi-metal oxide. Specifically, the evaporation apparatus used was an evaporation coating device. When the pressure in the vacuum chamber dropped to 5×10 -4 Pa vacuum environment, Au was evaporated at a speed of 0.01 nm / s.

[0108] Example 2 An artificial synapse based on layered multi-metal oxides and its preparation method

[0109] An artificial synapse based on layered multi-metal oxides, which uses aluminum foil as the bottom electrode and Na 0.66 Mg 0.28 Mn 0.72O2 is used as the functional layer, pectin composite membrane is used as the solid electrolyte, and Au is used as the top electrode.

[0110] The preparation method of the above-mentioned artificial synapse based on layered multi-metal oxides:

[0111] The preparation method of Example 1 was followed, except that in step S7, 60 mg of water-soluble pectin with a molecular weight of not more than 150 was dissolved in 3 ml of water, and stirred at 70°C and 600 rpm for 40 min to obtain a solution, 150 μL of glycerol was added dropwise to the solution to obtain a glycerol-containing pectin solution, and the glycerol-containing pectin solution was stirred at 70°C and 600 rpm for 24 h. The complete injection area was 55 cm 2 The pectin composite film was prepared by placing it in a plastic surface dish and drying it at 60℃ for 2h to obtain a pectin composite film with a thickness of 15μm.

[0112] Example 3 An artificial synapse based on layered multi-metal oxides and its preparation method

[0113] An artificial synapse based on layered multi-metal oxides, which uses aluminum foil as the bottom electrode and Na 0.66 Mg 0.28 Mn 0.72 O2 was used as the functional layer, NaCl-doped pectin composite film was used as the solid electrolyte layer, and Au was used as the top electrode.

[0114] The preparation method of the above-mentioned artificial synapse based on layered multi-metal oxides:

[0115] The preparation method of Example 1 was followed, except that in step S7, drying was performed at 60° C. for 3 h to prepare a NaCl-doped pectin composite film with a thickness of 7 μm.

[0116] Example 4 An artificial synapse based on layered multi-metal oxides and its preparation method

[0117] An artificial synapse based on layered multi-metal oxides, which uses aluminum foil as the bottom electrode and Na 0.66 Mg 0.28 Mn 0.72 O2 was used as the functional layer, NaCl-doped pectin composite film was used as the solid electrolyte layer, and Au was used as the top electrode.

[0118] The preparation method of the above-mentioned artificial synapse based on layered multi-metal oxides:

[0119] The preparation method of Example 1 was followed, except that in step S7, drying was performed at 60° C. for 1 h to prepare a NaCl-doped pectin composite film with a thickness of 30 μm.

[0120] Example 5 Performance Testing of Artificial Synapses Based on Layered Multi-element Metal Oxides

[0121] In the nervous system, neurons communicate through synapses. When the membrane potential of the presynaptic neuron changes, it will cause the occurrence of presynaptic spikes and release neurotransmitters. These neurotransmitter substances will be transmitted to the postsynaptic neuron through the synapse, thereby affecting the membrane potential and activity state of the postsynaptic neuron. This embodiment simulates the release of an excitatory neurotransmitter with absolute short-range plasticity. The release of an excitatory neurotransmitter with absolute short-range plasticity means that in certain neuronal synapses, the release of excitatory neurotransmitters only affects the postsynaptic neurons near the presynaptic spike, while having no obvious effect on the postsynaptic neurons farther away.

[0122] 1. Semiconductor Characteristic Analysis and Testing

[0123] (1) Experimental methods

[0124] The artificial synapse based on layered multi-metal oxide prepared in Example 1 was used as a test sample. The probe of electrode SUM1 was connected to aluminum foil as the bottom electrode, and the probe of electrode SUM2 was connected to Au as the top electrode.

[0125] A Keithley 4200-SCS semiconductor characteristic analyzer was used to continuously apply a 0.5V reading voltage to electrode SUM1, and a single signal with a duration of 0.05s and an amplitude of 5V was applied to electrode SUM2 as a presynaptic spike. The excitatory postsynaptic current diagram under a single 0.05s positive pulse stimulation was obtained ( Figure 2 ).

[0126] The artificial synapse based on layered multi-metal oxide prepared in Example 2 was used as a test sample. The probe of electrode SUM1 was connected to aluminum foil as the bottom electrode, and the probe of electrode SUM2 was connected to Au as the top electrode.

[0127] A Keithley 4200-SCS semiconductor characteristic analyzer was used to continuously apply a 0.5V reading voltage to electrode SUM1, and a single signal with a duration of 0.05s and an amplitude of 5V was applied to electrode SUM2 as a presynaptic spike. The excitatory postsynaptic current diagram under a single 0.05s positive pulse stimulation was obtained ( Figure 3 ).

[0128] (2) Experimental results

[0129] like Figure 2 As shown, the artificial synapse prepared in Example 1 uses NaCl-doped pectin composite membrane as solid electrolyte, and the H + and Na +Migrate to the layered multi-metal oxide and dope it, inducing the transmission of electron carriers, and outputting an excitatory postsynaptic current gain of 0.42μA. Figure 3 As shown, the solid electrolyte of the artificial synapse prepared in Example 2 is a pectin composite membrane without NaCl doping, and the output excitatory postsynaptic current gain is 0.0168 μA. This shows that the artificial synapse prepared in Example 1 has an excitatory postsynaptic current intensity that is approximately 25 times higher than that of Example 2.

[0130] The artificial synapses based on layered multinary metal oxides reported in the prior art (Liu Qiang, Ni Yao, Liu Lu, et al. Artificial synapses based on layered multinary metal oxides [J]. Acta Physica Sinica, 2022, 71(14): 313-320.) have a current response gain of nA level. The artificial synapses based on layered multinary metal oxides prepared in Examples 1 and 2 of the present invention have a current response gain of up to μA level. Therefore, using the pectin composite membrane as the solid electrolyte of the artificial synapse can improve the current responsiveness of the artificial synapse, and the artificial synapse prepared using the NaCl-doped pectin composite membrane as the solid electrolyte has a higher current responsiveness.

[0131] After the electrical stimulation is removed, the artificial synapse based on layered multi-metal oxide prepared in Example 1 stores H in the shallow trap on the layered multi-metal oxide. + and Na + The dedoping process is very short. Compared with the artificial synapse prepared in Example 2, the postsynaptic current reset time is not significantly increased, and it degrades to 0.3% of the initial value within 3 seconds. The semiconductor properties of the artificial synapses based on layered multi-metal oxides prepared in Examples 3 and 4 are the same as those in Example 1.

[0132] 2. Semiconductor Characteristics Analysis and Testing

[0133] (1) Experimental methods

[0134] The artificial synapse based on layered multi-metal oxide prepared in Example 1 was used as a test sample. The probe of electrode SUM1 was connected to aluminum foil as the bottom electrode, and the probe of electrode SUM2 was connected to Au as the top electrode.

[0135] A Keithley 4200-SCS semiconductor characteristic analyzer was used to continuously apply a 0.5V reading voltage to electrode SUM1, and 50 signals with a duration of 0.05s, a frequency of 10Hz, and an amplitude of 5V were applied to electrode SUM2 as presynaptic spikes. The excitatory postsynaptic current diagram under 50 0.05s positive pulse stimulations was obtained ( Figure 4 ).

[0136] After the stimulation of electrode SUM2 was removed, the postsynaptic current decay diagram after 50 0.05s positive pulse stimulations was obtained as shown in the figure below. Figure 5 shown.

[0137] The artificial synapse based on layered multi-metal oxide prepared in Example 2 was used as a test sample. The probe of electrode SUM1 was connected to aluminum foil as the bottom electrode, and the probe of electrode SUM2 was connected to Au as the top electrode.

[0138] A Keithley 4200-SCS semiconductor characteristic analyzer was used to continuously apply a 0.5V reading voltage to electrode SUM1, and 50 signals with a duration of 0.05s, a frequency of 10Hz, and an amplitude of 5V were applied to electrode SUM2 as presynaptic spikes. The excitatory postsynaptic current diagram under 50 0.05s positive pulse stimulations was obtained ( Figure 6 ).

[0139] After the stimulation of electrode SUM2 was removed, the postsynaptic current decay diagram after 50 0.05s positive pulse stimulations was obtained as shown in the figure below. Figure 7 shown.

[0140] (2) Experimental results

[0141] like Figure 4 As shown in the figure, when 50 presynaptic spikes with an amplitude of 5V and a duration of 0.05s were continuously applied to the top electrode of the artificial synapse prepared in Example 1, and a reading voltage of 0.5V was applied to the bottom electrode at the same time, the output excitatory postsynaptic current gain was further increased to 1.47μA, indicating that the continuous application of positive pulses can enhance the release of excitatory neurotransmitters.

[0142] like Figure 6 As shown, when 50 presynaptic spikes with an amplitude of 5V and a duration of 0.05s are continuously applied to the top electrode of the artificial synapse prepared in Example 2, and a reading voltage of 0.5V is applied to the bottom electrode at the same time, the continuous application of positive pulses can also enhance the release of excitatory neurotransmitters, and the output excitatory postsynaptic current gain is increased to 0.079μA.

[0143] Compared with the artificial synapse prepared in Example 2, the gain of the output excitatory postsynaptic current after continuous application of positive pulses in Example 1 is increased by about 18 times.

[0144] according to Figure 5 and Figure 7 It can be seen that after the stimulation of electrode SUM2 is removed, the H stored in the layered multi-metal oxide shallow trap by the artificial synapse prepared in Example 1 is + and Na +The dedoping process is very short. Compared with the artificial synapse prepared in Example 2, the postsynaptic current reset time does not increase significantly, degenerating to 10% of the initial value within 3 seconds. The fitted carrier lifetime is 342 ms, that is, the time required from the end of stimulation to the recovery of the postsynaptic current to the initial level is approximately 342 milliseconds, while the fitted carrier lifetime of the artificial synapse prepared in Example 2 is 977 ms. Therefore, it can be seen that the artificial synapse prepared in Example 1 has a faster current reset speed than the artificial synapse prepared in Example 2.

[0145] As can be seen, the artificial synapses prepared in Examples 1 and 2 both have fast current reset rates. The artificial synapse prepared in Example 1, using a NaCl-doped pectin composite membrane as a solid electrolyte, has a higher current response speed than the artificial synapse prepared in Example 2, using a non-NaCl-doped pectin composite membrane as a solid electrolyte, while maintaining a fast current reset rate. The artificial synapses based on layered multinary metal oxides prepared in Examples 3 and 4 have the same semiconductor properties as those in Example 1.

[0146] That is, the artificial synapses prepared in Examples 1, 3 and 4 of the present invention can quickly respond to and adapt to different input signals, which is of great significance for realizing efficient brain-like computing and artificial intelligence systems.

[0147] 3. Semiconductor Characteristics Analysis and Testing

[0148] (1) Experimental methods

[0149] The artificial synapse based on layered multi-metal oxide prepared in Example 1 was used as a test sample. A reading voltage of 0.5 V was continuously applied to electrode SUM1 using a Keithley 4200-SCS semiconductor characteristic analyzer. A single signal with a duration of 0.05 s and an amplitude of 5 V was applied to electrode SUM2 to represent a short signal in Morse code; a single signal with a duration of 0.15 s and an amplitude of 5 V was applied to represent a long signal in Morse code. The test obtained excitatory postsynaptic current graphs representing the four letters A (short / long), B (long / short / short / short), C (long / short / long / short), and D (long / short / short) ( Figure 8 ).

[0150] (2) Experimental results

[0151] according to Figure 8It can be seen that in an experiment using the artificial synapse prepared in Example 1 and using a NaCl-doped pectin composite membrane as a solid electrolyte to perform Morse coding on the four letters A, B, C, or D, the excitatory postsynaptic current representing a short signal ranged from 0.44 to 0.67 μA; the excitatory postsynaptic current representing a long signal ranged from 0.84 to 0.94 μA. The fault tolerance current between short and long signals was greater than 0.17 μA, meaning that the output signal can be classified and encoded using only a single comparator. This has important implications for applications in large-scale artificial synapse array integration and system design. The semiconductor properties of the artificial synapses based on layered multi-metal oxides prepared in Examples 3 and 4 were the same as those in Example 1.

[0152] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. An artificial synapse based on layered multi-metal oxides, characterized in that: The artificial synapse comprises a bottom electrode, a functional layer, a solid electrolyte layer and a top electrode layer arranged from bottom to top, wherein the functional layer is a layered multi-metal oxide, the solid electrolyte layer is a pectin composite film or a pectin composite film containing 0.4-0.6% NaCl by mass, and the general formula of the layered multi-metal oxide is Na 0.66 Mg 0.28 Mn 0.72 O2.

2. The artificial synapse according to claim 1, wherein The material of the bottom electrode is a good electrical conductor.

3. The artificial synapse according to claim 1, wherein The bottom electrode is made of one metal selected from copper, aluminum, gold, and silver, or a composite of two or more metals, or indium tin oxide or zinc aluminum oxide.

4. The artificial synapse according to claim 1, wherein The thickness of the solid electrolyte layer is 5 to 30 μm.

5. The artificial synapse according to claim 1, wherein The thickness of the functional layer is 5 to 10 μm.

6. The method for preparing an artificial synapse according to claim 1, wherein: The following steps are involved: S21. will meet Na 0.66 Mg 0.28 Mn 0.72 Mixing mixed metal oxide powders with an O2 ratio and a polymer adhesive to obtain a slurry, placing the slurry on a bottom electrode, applying it evenly, and then drying it to a constant weight to obtain a bottom electrode covered with a functional layer of uniform thickness; S22. Laminating the solid electrolyte layer onto the functional layer on the bottom electrode after drying in step S21, and thermally evaporating a top electrode on the solid electrolyte layer to obtain an artificial synapse based on a layered multi-metal oxide.

7. A method for preparing a pectin composite membrane for a solid electrolyte of an artificial synapse, characterized in that: The following steps are involved: S11. The water-soluble pectin and water are mixed uniformly and then completely dissolved in glycerol to obtain a mixed solution, wherein the ratio of the water-soluble pectin, water and glycerol is 40 to 70 mg water-soluble pectin: 2 to 3.5 ml water: 100 to 200 μl glycerol; S12. The mixed solution prepared in step S11 was injected into the mold, 40 to 70 μl of the mixed solution was added dropwise per square centimeter of the mold, and dried at 50 to 70 ° C for 1 to 4 h to obtain a pectin composite film; The artificial synapse is the artificial synapse according to any one of claims 1 to 6.

8. A method for preparing a pectin composite film containing 0.4-0.6% NaCl by mass as a solid electrolyte for artificial synapses, characterized in that: The following steps are involved: S11. Mix water-soluble pectin, water, and NaCl, then add glycerol and mix thoroughly to obtain a mixed solution. The ratio of water-soluble pectin, water, and glycerol is 40-70 mg water-soluble pectin: 2-3.5 ml water: 100-200 μl glycerol. The mass fraction of NaCl in the mixed solution is 0.4-0.6%. S12. The mixed solution prepared in step S11 was injected into the mold, 40 to 70 μl of the mixed solution was added dropwise per square centimeter of the mold, and dried at 50 to 70 ° C for 1 to 4 h to obtain a pectin composite film; The artificial synapse is the artificial synapse according to any one of claims 1 to 6.

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