Memristor, method of making a memristor, and artificial synapse device

Abstract

The application discloses a memristor, a method for preparing the same and an artificial synapse device, and the memristor comprises a glass cone and a polyelectrolyte structure on the inner wall of the glass cone; the glass cone has a first end opening and a second end opening arranged oppositely, the diameter of the first end opening is smaller than that of the second end opening, and the polyelectrolyte structure is located on the inner wall of the first end opening. Thus, the memristor has low power consumption of a picojoule level, a low working potential and high efficiency. When a pulse potential stimulus is applied, the memristor can generate a double-pulse facilitation and a double-pulse inhibition effect similar to a neuron synapse, and due to the existence of an ion effect, the effective regulation of the plasticity of the system can be realized. Further, the signal transduction function based on ions can be realized by being combined with a micro-injection system. In addition, the memristor has excellent stability and designability and the like.

Description

Technical Field

[0001] This invention belongs to the field of electronic device fabrication, specifically relating to memristors, methods for fabricating memristors, and artificial synaptic devices. Background Technology

[0002] Memristors are the fourth type of basic component, following capacitors, resistors, and inductors. Their fundamental characteristic is that the charge on the device is modulated by magnetic flux, giving memristors a history-dependent impedance, thus exhibiting memory-like properties. With the continuous development of big data technology, the speed and efficiency limitations of traditional computing architectures are becoming increasingly apparent. Addressing this von Neumann bottleneck, researchers hope to utilize these devices to simulate the brain's computing patterns, achieving a series of brain-like computing functions in hardware, such as parallel computing, pattern recognition, and artificial neural network construction. While researchers have developed a series of neuromorphic functions based on solid-state memristors such as conductive bridge memristors and metal-oxide-semiconductor memristors, the efficiency and functionality of memristor devices have not yet reached the power consumption and efficiency of neurons.

[0003] Therefore, it is necessary to improve existing memristors. Summary of the Invention

[0004] The present invention aims to improve at least one of the above-mentioned technical problems to at least some extent.

[0005] This invention provides a memristor comprising a glass cone and a polyelectrolyte structure located on the inner wall of the glass cone. The glass cone has a first end opening and a second end opening disposed opposite to each other, the diameter of the first end opening being smaller than the diameter of the second end opening. The polyelectrolyte structure is located on the inner wall of the first end opening. Therefore, based on the ion-based action mechanism, the memristor of this invention exhibits low power consumption at the picojoule level, a low operating potential, and high efficiency. When stimulated with a pulse potential, the memristor of this invention can generate a double-pulse facilitator and a double-pulse inhibition effect similar to that of a neuronal synapse. Simultaneously, due to the presence of ion effects, the plasticity of the system can be effectively controlled by adjusting the solution composition within the device. Furthermore, by combining it with a microinjection system, ion-based signal transduction functions can be achieved. In addition, the memristor of this invention also possesses advantages such as excellent stability and designability.

[0006] According to an embodiment of the present invention, the material forming the polyelectrolyte structure includes a polyvinyl imidazole salt.

[0007] According to an embodiment of the present invention, the diameter of the first end opening is 0.1 to 15 micrometers.

[0008] According to an embodiment of the present invention, the thickness of the polyelectrolyte structure is 100-500 nm; if the thickness of the polyelectrolyte structure is too small, it will weaken the device's memory capability, while an excessively thick polyelectrolyte structure will hinder transmission behavior.

[0009] According to an embodiment of the present invention, in the extending direction of the glass cone sidewall, the ratio of the extension length of the polyelectrolyte structure to the diameter of the first end opening is greater than or equal to 10; if the extension length of the polyelectrolyte structure is too small, the memory function of the device will be weakened.

[0010] The present invention also provides a method for preparing the memristor described above, the method comprising: providing a glass cone having a first end opening and a second end opening disposed opposite to each other, the diameter of the first end opening being smaller than the diameter of the second end opening; and forming a polyelectrolyte structure on the inner wall of the first end opening of the glass cone. Thus, this method possesses all the features and advantages of the memristor described above, which will not be repeated here.

[0011] According to an embodiment of the present invention, forming a polyelectrolyte structure includes: immersing the first end opening of the glass cone in an initiator solution for impregnation, then adding a catalyst and a vinylimidazole monomer to carry out a reaction, thereby forming a polyelectrolyte structure on the inner wall of the glass cone.

[0012] According to an embodiment of the present invention, the initiator is 2-bromo-2-methyl-N-[3-(triethoxysilyl)propyl]propionamide; the impregnation treatment time is 8-15 h; optionally, the initiator solution is an acetonitrile solution containing the initiator; the mass fraction of the initiator in the initiator solution is 3-7%; the reaction further includes: after the impregnation treatment, washing the glass cone sequentially with acetonitrile, ethanol, and water, and then adding a catalyst and a vinylimidazole monomer.

[0013] According to embodiments of the present invention, the vinylimidazole monomer is composed of a cation and an anion, wherein the cation includes at least one of 1-vinyl-3-ethylimidazole cation, 1-vinyl-3-butylimidazole cation, and 1-vinyl-3-octylimidazole cation, and the anion includes Cl... - ,Br - BF4 - PF6 - At least one of them.

[0014] According to an embodiment of the present invention, the vinylimidazole monomer is added in the form of a vinylimidazole monomer solution, wherein the solvent of the vinylimidazole monomer solution includes at least one of water, ethanol, and DMF; and the mass ratio of the vinylimidazole monomer to the solvent in the vinylimidazole monomer solution is 1:(15-25).

[0015] According to an embodiment of the present invention, the catalyst comprises cuprous bromide and pentamethyldiethylenetriamine.

[0016] According to an embodiment of the present invention, the molar ratio of the vinylimidazole monomer, the cuprous bromide and the pentamethyldiethylenetriamine is (95-105):(3-7):(13-17).

[0017] According to an embodiment of the present invention, the reaction is carried out under oxygen-free and nitrogen-protected conditions; the reaction temperature is 65–75°C, and the reaction time is 20–30 h.

[0018] The present invention also provides an artificial synaptic device, comprising the memristor described above or the memristor prepared by the method described above. Thus, the artificial synaptic device possesses all the features and advantages of the memristor described above or the method described above, which will not be repeated here.

[0019] According to an embodiment of the present invention, the artificial synapse device further includes: an internal filling fluid, an external solution, a working electrode, and a reference electrode; the internal filling fluid fills a glass cone in the memristor, the first end opening of the glass cone is immersed in the external solution, at least a portion of the working electrode is in contact with the internal filling fluid, and at least a portion of the reference electrode is in contact with the external solution.

[0020] According to an embodiment of the present invention, the internal filling solution and the external solution are independently selected from at least one of NaCl, NaBF4, NaClO4, KCl, KBF4, and KClO4; the concentrations of the internal filling solution and the external solution are independently selected from 0.1 mmol / L to 1 mol / L. Attached Figure Description

[0021] Figure 1A This is a flowchart illustrating the fabrication process of a memristor in one embodiment of the present invention;

[0022] Figure 1B This is a scanning electron microscope image of a memristor in one embodiment of the present invention. The device shown in the image has a diameter of 10 μm.

[0023] Figure 1C This is a schematic diagram of a device for characterizing the properties of a memristor in one embodiment of the present invention;

[0024] Figure 2 These are the current-voltage response images of the artificial synaptic devices obtained in the embodiments and comparative examples of the present invention under a triangular wave.

[0025] Figure 3A This is the current response curve of the artificial synaptic device under a continuous positive pulse voltage in a 10mM potassium chloride solution, as described in this embodiment of the invention.

[0026] Figure 3B This is the current response curve of the artificial synaptic device under continuous negative pulse voltage in a 10mM potassium chloride solution in an embodiment of the present invention;

[0027] Figure 3C In this embodiment of the invention, the current response curves of the artificial synaptic device under continuous negative pulse voltage and continuous positive pulse voltage in 10mM potassium chloride solution are shown as changes with pulse interval.

[0028] Figure 4A This is a graph showing the trend of device power consumption and ionic conductivity of an artificial synaptic device as a function of size, according to an embodiment of the present invention.

[0029] Figure 4B This is a graph showing the trend of device power consumption and ionic conductance of an artificial synaptic device as a function of pulse amplitude, according to an embodiment of the present invention.

[0030] Figure 5A This is a current-voltage response diagram of an artificial synaptic device in different internal filling fluids in an embodiment of the present invention;

[0031] Figure 5B This is the current response curve of the artificial synapse device under continuous positive pulse voltage stimulation in different internal filling fluids in an embodiment of the present invention;

[0032] Figure 5C This is the current response curve of the artificial synaptic device under continuous negative pulse voltage stimulation in different internal filling fluids in an embodiment of the present invention;

[0033] Figure 5D This is a curve showing the variation of the difference in positive current response of the artificial synapse device with the pulse interval in different internal filling fluids in an embodiment of the present invention.

[0034] Figure 5E This is a curve showing the variation of the negative current response difference of the artificial synapse device with the pulse interval in different internal filling fluids in an embodiment of the present invention.

[0035] Figure 6A This is an embodiment of the invention, showing the curves of the difference in current response under continuous positive pulse voltage stimulation in artificial synaptic devices filled with liquid at different concentrations, as a function of pulse intervals.

[0036] Figure 6B This is an embodiment of the invention, showing the curves of the difference in current response under continuous negative pulse voltage stimulation in artificial synaptic devices filled with liquid at different concentrations, as a function of pulse intervals.

[0037] Figure 7 This is a schematic diagram of a device for realizing chemical signal-to-electrical signal transduction based on the artificial synaptic device of the present invention in an embodiment of the present invention;

[0038] Figure 8 According to an embodiment of the present invention, the chemical signal-to-electrical signal transduction function enables the artificial synaptic device to generate a peak-shaped electrical signal response under continuous neurotransmitter stimulation. Detailed Implementation

[0039] The embodiments of this application are described in detail below. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they are performed in accordance with the techniques or conditions described in the literature in this field or according to the product instructions. Reagents used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0040] This invention provides a memristor comprising a glass cone and a polyelectrolyte structure located on the inner wall of the glass cone. The glass cone has a first end opening and a second end opening disposed opposite to each other, the diameter of the first end opening being smaller than the diameter of the second end opening. The polyelectrolyte structure is located on the inner wall of the first end opening. The inventors have discovered that, compared with traditional electrochemical memristors, phase-change memristors, and other memory devices, the memristor of this invention can achieve basic short-term plasticity functions such as double-pulse facilitation, double-pulse suppression, and dynamic filtering. The memristor of this invention has advantages such as low power consumption and designability. Specifically, due to its ion-based mechanism, the memristor of this invention can achieve picojoule-level substrate power consumption and operate at low operating potentials below 1V, making it widely applicable in complex environments such as in-situ implanted devices. Compared with traditional solid-state devices, the plasticity of the memristor of this invention stems from the time dependence of the confined ion migration process, thus exhibiting many characteristics such as low power consumption, designability, and ease of control. Meanwhile, the combination of the memristor and microinjection device of the present invention can realize the simulation of chemical signal-electric signal transduction behavior.

[0041] According to an embodiment of the present invention, the material forming the polyelectrolyte structure includes a polyvinyl imidazole salt.

[0042] According to an embodiment of the present invention, the diameter of the first end opening is 0.1 to 15 micrometers, for example, 0.1 micrometer, 1 micrometer, 3 micrometer, 5 micrometer, 7 micrometer, 10 micrometer, or 15 micrometer. If the diameter of the first end opening is too small, it will be difficult to modify the polyelectrolyte structure; while if the diameter of the first end opening is too large, the memory behavior of the device will tend to disappear.

[0043] According to an embodiment of the present invention, the thickness of the polyelectrolyte structure is 100-500 nm; if the thickness of the polyelectrolyte structure is too small, it will weaken the device's memory capability, while an excessively thick polyelectrolyte structure will hinder transmission behavior.

[0044] According to an embodiment of the present invention, in the extending direction of the glass cone sidewall, the ratio of the extension length of the polyelectrolyte structure to the diameter of the first end opening is greater than or equal to 10; if the extension length of the polyelectrolyte structure is too small, the memory function of the device will be weakened.

[0045] According to a practical example of the present invention, the neuromorphic function of the memristor can be characterized by the device's volt-ampere characteristics and continuous pulse stimulation response. When a triangular wave potential is applied to the device, the device exhibits a "figure-eight" crossover characteristic in its current-voltage response under the triangular wave. The presence of a crossover point between the pre-scan and post-scan volt-ampere curves confirms the existence of its neuromorphic function. The triangular wave range can be ±(1~5V), such as -1V to 1V, and the scan rate can be (0.01~10)V / s, such as 0.05V / s, 0.1V / s, and 1V / s. According to a practical example of the present invention, the neuromorphic function of the device can also be verified by applying continuous pulse waveforms to the device. The pulse potential can be ±0.1~2V, such as 0.1V, 1V, 2V, -0.1V, -1V, -2V, etc.; the pulse width can be 5~100ms, such as 5ms, 10ms, 20ms; and the pulse interval can be 1~1000ms, such as 10ms, 20ms, 50ms, etc. If the device's current response to pulsed voltage gradually increases or decreases with each consecutive pulse, and the degree of change gradually decreases with increasing pulse interval, then the device exhibits neuromorphic functionality. Furthermore, the degree of change in the device's current response under the same conditions characterizes the strength of its neuromorphic function.

[0046] According to a practical example of the present invention, the power consumption of the memristor of the present invention can be controlled by adjusting the device size, applying waveforms, etc. Reducing the device size and lowering the pulse voltage amplitude can reduce the power consumption of the device to the pJ level per pulse signal.

[0047] The present invention also provides a method for preparing the memristor described above, the method comprising: providing a glass cone having a first end opening and a second end opening disposed opposite to each other, the diameter of the first end opening being smaller than the diameter of the second end opening; and forming a polyelectrolyte structure on the inner wall of the first end opening of the glass cone. Thus, this method possesses all the features and advantages of the memristor described above, which will not be repeated here.

[0048] According to an embodiment of the present invention, forming a polyelectrolyte structure includes: immersing the first end opening of the glass cone in an initiator solution for impregnation, then adding a catalyst and a vinylimidazole monomer to carry out a reaction, thereby forming a polyelectrolyte structure on the inner wall of the glass cone.

[0049] According to an embodiment of the present invention, the initiator is 2-bromo-2-methyl-N-[3-(triethoxysilyl)propyl]propionamide; the impregnation treatment time is 8-15 hours, thereby obtaining a glass cone with an inner wall modified with an initiator through the impregnation treatment.

[0050] According to some embodiments of the present invention, the initiator solution is an acetonitrile solution containing an initiator; the mass fraction of the initiator in the initiator solution is 3-7%, for example 3%, 4%, 5%, 6%, or 7%.

[0051] According to some embodiments of the present invention, the reaction further includes: after the impregnation treatment, washing the glass cone sequentially with acetonitrile, ethanol, and water, followed by adding a catalyst and vinylimidazole monomer. This removes initiator and other impurities that have not effectively adhered to the inner wall of the first end opening of the glass cone.

[0052] According to embodiments of the present invention, the vinylimidazole monomer is composed of a cation and an anion, wherein the cation includes at least one of 1-vinyl-3-ethylimidazole cation, 1-vinyl-3-butylimidazole cation, and 1-vinyl-3-octylimidazole cation, and the anion includes Cl... - ,Br - BF4 - PF6 - At least one of them.

[0053] According to some embodiments of the present invention, the vinylimidazole monomer is added in the form of a vinylimidazole monomer solution, wherein the solvent of the vinylimidazole monomer solution includes at least one of water, ethanol, and DMF; in the vinylimidazole monomer solution, the mass ratio of the vinylimidazole monomer to the solvent is 1:(15-25), for example, it can be 1:15, 1:17, 1:20, 1:22, or 1:25.

[0054] According to some embodiments of the present invention, the catalyst comprises cuprous bromide and pentamethyldiethylenetriamine. Thus, the initiating groups on the inner wall of the glass cone, under the action of the catalyst, can undergo a polymerization reaction with a vinylimidazolium monomer solution, and polyvinylimidazolium salt is grown in situ via surface-initiated atom transfer radical polymerization to obtain a polyelectrolyte-confined fluid device, wherein the polyelectrolyte confinement modification is a polyimidazolium cationic brush.

[0055] According to an embodiment of the present invention, the molar ratio of the vinylimidazole monomer, the cuprous bromide, and the pentamethyldiethylenetriamine is (95-105):(3-7):(13-17), for example, it can be 96:(3-7):(13-17), 97:(3-7):(13-17), 98:(3-7):(13-17), 99:(3-7):(13-17), 100:(3-7):(13-17), 101:(3-7):(13-17). ~17), 102:(3~7):(13~17), 103:(3~7):(13~17), 104:(3~7):(13~17), (95~105):4:(13~17), (95~105):5:(13~17), (95~105):6:(13~17), (95~105):(3~7):14, (95~105):(3~7):15 or (95~105):(3~7):16. The inventors found that when the content of each component is within the above range, the resulting ion-based memristor has lower noise and better memory effect. Excessive vinylimidazolium monomer content or excessive catalyst content will make the current-voltage characteristics of the memristor unstable; excessively low vinylimidazolium monomer content or excessively low catalyst content will result in a weak memory effect or even almost no neuromorphic function of the device.

[0056] According to some embodiments of the present invention, the reaction is carried out under oxygen-free and nitrogen-protected conditions.

[0057] According to some embodiments of the present invention, the reaction temperature is 65-75°C, for example, 65°C, 67°C, 69°C, 70°C, 72°C, or 75°C; the reaction time is 20-30 hours, for example, 20 hours, 22 hours, 24 hours, 26 hours, 28 hours, or 30 hours.

[0058] The present invention also provides an artificial synaptic device, comprising the memristor described above or the memristor prepared by the method described above. Thus, the artificial synaptic device possesses all the features and advantages of the memristor described above or the method described above, which will not be repeated here.

[0059] According to an embodiment of the present invention, the artificial synapse device further includes: an internal filling fluid, an external solution, a working electrode, and a reference electrode; the internal filling fluid fills a glass cone within the memristor, the first end opening of the glass cone is immersed in the external solution, at least a portion of the working electrode is in contact with the internal filling fluid to achieve circuit conduction, and at least a portion of the reference electrode is in contact with the external solution to achieve circuit connection. It should be noted that further performance testing of the device can be performed by connecting it to instruments such as a patch-clamp amplifier.

[0060] According to an embodiment of the present invention, the internal filling liquid and the external solution are independently selected from at least one of NaCl, NaBF4, NaClO4, KCl, KBF4, and KClO4; those skilled in the art can adjust the plasticity function of the device by adjusting the composition of the internal filling liquid.

[0061] According to some embodiments of the present invention, the concentrations of the internal filling solution and the external solution are independently selected from 0.1 mmol / L to 1 mol / L, for example, 1 mmol / L, 10 mmol / L, 100 mmol / L, or 1 mol / L.

[0062] In some embodiments of the present invention, multiple solutions can be mixed in a certain proportion, and the mixed solution can be used as the internal filling solution. For example, the internal filling solution can be a mixture of 1 mmol / L NaClO4 solution and 9 mmol / L NaCl solution.

[0063] It should be noted that the internal filling fluid needs to be filtered beforehand to remove particulate impurities.

[0064] It should be noted that the memory capacity of the artificial synaptic device is also modulated by the type and properties of the salt solution within the device. The anion-selective effect of this device results in a strong memory effect in hydrochloric acid solutions such as NaCl and KCl; while in tetrafluoroborate and perchlorate solutions, the memory effect is relatively weaker due to the presence of ion-selective effects. These variations in the strength of the simulated neural function can be characterized by the device's current-voltage characteristics or its response to continuous pulse stimulation.

[0065] According to an embodiment of the present invention, at least one of the working electrode and the reference electrode is an Ag / AgCl wire, which is connected to the solution for further testing.

[0066] The neuronal plasticity simulation mechanism of the device of the present invention is as follows:

[0067] The model provided by this invention is based on the ion transport behavior confined within an electrolyte brush. The strong electrostatic force provided by the polyelectrolyte chains greatly enhances the ability of the confined space to regulate ions, resulting in a history-dependent characteristic of ion transport behavior within the confined space, thus generating neuromorphic capabilities. When a certain electric field is applied, the gradual increase or decrease in ion concentration over time causes changes in the ion conductivity of the system. Figure 2As shown, the current-voltage characteristic curves of this type of neural synaptic device under a triangular wave exhibit a figure-eight cross-shaped feature, proving the existence of its memristor characteristics; while for the unmodified bare substrate, its negligible modulation capability results in a resistive linear current-voltage response. Simultaneously, when the driving electric field is removed, the limitation of the ion diffusion rate allows its ionic conductivity to be maintained for a certain period, thereby giving the device history-dependent characteristics and related synaptic plasticity. Figure 3A , Figure 3B , Figure 3C As shown, with stimulation from two consecutive potential pulses with a 10ms interval and a pulse width of 10ms, the ionic conductance of the device changes, exhibiting both double-pulse facilitation and double-pulse suppression functions. Simultaneously, as the interval gradually increases, this enhanced ionic conductance effect gradually weakens and disappears with a double exponential function trend.

[0068] Due to the aforementioned mechanisms, the plasticity of this type of neural synaptic device does not depend on a strong electric field, thus enabling it to perform its functions with relatively low energy consumption. For example... Figure 4A , Figure 4B As shown, as device size continues to shrink, the power consumption required for the same bit drive gradually decreases. In a 150nm device, under negative potential drive, as the applied potential decreases, a potential pulse of -0.1V and 10ms can still drive the plasticity function. At this time, the device power consumption can reach an extremely low level of 0.7pJ / spike.

[0069] The aforementioned ion-based device structure, while exhibiting short-term plasticity, also possesses synaptic plasticity that can be modulated through ion-surface interactions because its functions are based on the interaction of ions in the solution phase. Stronger ion-surface interactions lead to the formation of ion-pair structures within the device, altering the total amount of freely moving ions and thus changing the device's plasticity. For example... Figure 5A As shown, when the internal filling solution of the synaptic device changes from 10 mmol / L NaCl to 10 mmol / L NaBF4 or 10 mmol / L NaClO4, the device's volt-ampere response shows that the range of its ionic conductivity changes with the type of ion; the resistive switching range decreases in NaClO4 and increases in NaBF4. Meanwhile, as... Figure 5B , Figure 5D This effect further alters the device's dual-pulse facilitation capability, changing the degree of change in ion conductivity under continuous positive pulse stimulation; simultaneously, the pulse interval (i.e., retention time) required for the dual-pulse facilitation effect to disappear is also reduced. Meanwhile, as... Figure 5C , Figure 5E As shown, this effect also alters the changes in ionic conductivity and retention time of the device under negative pulse stimulation. In other words, the synaptic plasticity of the device is modulated by the properties of the internal filling fluid.

[0070] Similarly, the device's plasticity also changes when the ionic strength of the internal filling liquid is altered. For example... Figure 6A , Figure 6B As shown, when the internal filling solution is changed from 100 mmol / L KCl to 10 mmol / L or 1 mmol / L KCl solution, the retention time of the system gradually increases due to the changes in the system's capacitance and surface effect. This indicates that the device is a type of synaptic-like device with adjustable and malleable characteristics.

[0071] Furthermore, based on the fluid-filled structure's fluidity and malleability, the artificial synapse device of this invention, combined with a microinjection pump, can achieve the function of transducing chemical signals into electrical signals. For example... Figure 7 As shown, a microinjection pump can be used to control the fluid filling within the device in real time, simulating the transduction of neuronal chemical signals to electrical signals under complex electrolyte conditions. An artificial synapse device is inserted into the solution and connected to a circuit via a working electrode and a reference electrode. A heated and drawn capillary is inserted into the conical end of the device, and the capillary is connected to the microinjection pump to control the release rate. When a certain background potential is applied, the neurotransmitter-like solution released by the microinjection pump can stimulate signal transduction. The heated and drawn capillary can be obtained by heating and melting a plastic tube, and its size can be 50–200 micrometers, such as 75 micrometers, and it is sealed to the microinjection pump. The neurotransmitter-like solution can be a mixture of NaClO4 or NaBF4 and NaCl, with a total concentration of 1–1000 mmol / L. The concentration ratio of NaClO4 or NaBF4 to NaCl can be 1:(1–19), such as 0.5 mmol / L NaClO4:9.5 mmol / L NaCl. The internal filling solution and external solution are both NaCl solutions, with the same ionic strength as the neurotransmitter solution. The release rate and time of the neurotransmitter solution are 1–10 mL / s and 1–20 ms, respectively, such as a release rate of 5 mL / s for 1 ms. The applied background potential is -0.1 to -3 V, such as -1 V, -2 V, or -3 V. When the background potential is applied, the neurotransmitter release will cause a peak-like pulsed ion current signal, and there is a neuron-like hysteresis response behavior between the neurotransmitter release and the pulsed current. During the pulsed neurotransmitter release process, the device's ionic conductivity experiences a pulsed surge and then recovers, and there is a time lag between the pulse application and the response generation, i.e., this signal transduction process occurs. Exceeding this concentration ratio range or pulse range will cause irreversible changes in the device, causing this chemical signal-to-electrical signal transduction function to fail. In summary, by implanting a capillary into the front end of the artificial synapse device, the release of trace amounts of neurotransmitter solution under the control of a microinjection pump can be achieved. Simultaneously, when a negative voltage is applied to the artificial synaptic device to monitor changes in the system's ionic conductivity, such as Figure 8As shown, the artificial synaptic device generates a peak-shaped pulse current signal response under neurotransmitter stimulation, thereby realizing the simulation of the conversion from chemical signal to electrical signal.

[0072] The present invention will be further explained below with reference to specific embodiments. Unless otherwise specified, the experimental methods used in the following embodiments and comparative examples are conventional methods. Unless otherwise specified, the materials and reagents used in the following embodiments are commercially available.

[0073] Example 1

[0074] 1. Preparation of the glass nanotubes used

[0075] According to such Figure 1A The process shown can be used to fabricate synaptic-like devices based on polyelectrolyte confinement: First, a clean and dry borosilicate glass tube (outer diameter 1.50 mm, inner diameter 0.86 mm) is stretched using a CO2 laser with the following procedure to obtain a glass cone with a diameter of 3 micrometers at the first open end:

[0076] (Cycle 1) heat=420, filament=5, velocity=30, delay=128, pull=0;

[0077] (Cycle 2) heat=400, filament=4, velocity=20, delay=128, pull=0.

[0078] The drawn capillary tube was polished to enlarge its size, resulting in an unmodified glass cone with a diameter of 10 μm.

[0079] Then, a 5% acetonitrile solution of 2-bromo-2-methyl-N-[3-(triethoxysilyl)propyl]propionamide was injected into the tip of the glass cone and allowed to stand for 8-15 hours. Excess unreacted initiator was then removed by washing with acetonitrile, ethanol, and water sequentially to obtain an initiator-functionalized glass cone. Next, 1 g of 1-vinyl-3-butylimidazolium chloride monomer was added to 20 mL of deionized water and placed in a flask for deoxygenation for 30 minutes. Cuprous bromide, N,N,N′,N″,N″-pentamethyldiethylenetriamine (PMEDTA), and the initiator-functionalized glass substrate were placed in the flask and reacted for 24 hours under nitrogen protection and an oil bath at 70°C. The molar ratio of imidazole monomer / cuprous bromide / PMEDTA was 100:5:15. After the reaction, the device was cooled to room temperature and cleaned with deionized water to obtain a synaptic-like device based on a polyelectrolyte confined structure. Figure 1B To create a scanning electron microscope image of the completed device structure, the diameter of the opening at the first end of the glass cone shown in the image is 10 μm.

[0080] 2. I-V characteristic test of a single device

[0081] like Figure 1C The device was internally filled with 10 mM KCl solution and immersed in the same solution. Two Ag / AgCl electrodes were placed in the inner and outer solutions respectively and connected to the external circuit to apply voltage. A Heka ELP3 patch-clamp amplifier was used to apply potential and record current. The triangular wave scan range was -1V to 1V, the scan rate was 50mV / s, and the number of revolutions was set to 20. The volt-ampere characteristics of the device after stabilization are as follows: Figure 2 As shown, it is not difficult to see that compared with the bare glass substrate with linear current-voltage response, the current-voltage response of this synaptic-like device exhibits hysteresis characteristics, and there is an intersection point between the forward scan and the backward scan process, proving the existence of its synaptic-like performance.

[0082] 3. Short-term plasticity test

[0083] An artificial synaptic device is connected to an external test circuit. At least a portion of the working electrode and at least a portion of the reference electrode are in contact with the external solution. The working and reference electrodes are connected to the external circuit, and the internal filling liquid fills a glass cone. The tip of the glass cone is immersed in the external solution. The short-term plasticity of the artificial synaptic device is determined based on the electrical signal value output by the electrical signal detector. Specifically, the short-term plasticity of the device is determined by its retention time. The device retention time can be obtained by fitting the decay trend of the device ion current change with the pulse interval under continuous potential pulses.

[0084] The continuous potential pulse waveform parameters include: the potential remains at the resting potential Vr when there is no pulse, which is the crossover potential on the device's triangular wave volt-ampere response; the pulse potential Vp = ±0.1~2V; the pulse width tp = 5~100ms; and the pulse interval Δt = 1~1000ms.

[0085] like Figure 3A , Figure 3B The device's applied pulse potential setting includes the following parameters: pulse potential V p =2V or -2V, and resting potential V r Settings Figure 2 At the crossover potential (V) r =V cp This ensures the system remains in a steady state during this resting phase. Pulse width t p =10ms and pulse interval Δt = 10ms, sampling frequency set to 50kHz. Further adjust the value of pulse interval Δt, such as Figure 3C As shown, the response change ΔI to the ion current generated under continuous pulses PSCBy plotting the decay process Δt with the pulse interval, the retention time of the system can be obtained by fitting a double exponential function, thus quantitatively describing the short-term malleability of the device. Furthermore, by adjusting the CO2 laser pulling instrument program and functionalizing it using the aforementioned method, devices with diameters of 3 μm and 150 nm can be obtained in the same internal filling solution. Figure 3A The waveform can be obtained as follows Figure 4A The diagram shows the trends in power consumption and ionic conductance of the device as the size decreases. Furthermore, based on the above, by using a negative pulse and reducing the pulse potential amplitude, the following can be obtained: Figure 4B The power consumption of the device shown is a trend that varies with the applied pulse intensity.

[0086] 4. Short-term plasticity regulation

[0087] Building upon the previous findings, the device's plasticity can be modulated by the type and concentration of ions in the internal filling solution and external electrolyte solution. First, a triangular wave was applied to the device under different salt solution environments to obtain its volt-ampere characteristics. Specific parameters were set as follows: scan range -1V to 1V, scan rate 50mV / s. After the scan stabilized, the trend of the device's volt-ampere response with ion type and concentration was obtained. Furthermore, experiments on the modulation of the device's short-term plasticity were conducted based on the previous findings, with parameters set to V... p =2V or -2V, V r =V cp , t p =10ms, and by fitting the ion current response decay change of the system under two consecutive stimuli according to the double exponential decay trend, the retention time can be obtained as follows. Figure 5D , Figure 5E , Figure 6A , Figure 6B The decay trend curves shown illustrate the device's ability to be controlled by different types and concentrations of salt solutions.

[0088] As can be seen from the above discussion, artificial synaptic devices exhibit different short-term plasticity in different internal filling fluids and external solutions. The short-term plasticity of artificial synaptic devices can be controlled by the composition and concentration of the internal filling fluid and external solution.

[0089] 5. Chemical signal to electrical signal transduction function

[0090] like Figure 7As shown, a 150 μm diameter capillary tube, heated and melted, was sealed to a syringe with epoxy resin and filled with a mixed solution of 9 mmol / L NaCl and 1 mmol / L NaClO4. After thoroughly removing air bubbles from the device, it was inserted into the front end of the device, and its release behavior was manipulated using a microinjection pump. Both the internal filling solution and the external electrolyte were 10 mmol / L NaCl solution, and a -1 V potential was introduced to monitor changes in the system's ionic conductivity. During simulated neurotransmitter release, the microinjection pump was used to release the stimulus with parameters of a flow rate of 10 mL / min and a stimulation duration of 1 ms, as shown below. Figure 8 The device shown exhibits a hysteresis peak-shaped ion current signal response, i.e., chemical signal to electrical signal conversion behavior.

[0091] Comparative Example 1

[0092] Comparative Example 1 uses only laser drawing and polishing processes without surface functionalization. That is, the surface of the glass cone in Comparative Example 1 does not have a polyelectrolyte structure. The current-voltage characteristics of related devices were tested on the bare glass substrate (10 μm in diameter) prepared in Comparative Example 1.

[0093] Experiments showed that when the bare glass substrate prepared in Comparative Example 1 was used to test the current-voltage characteristics of the device, the reference... Figure 2 The bare glass substrate exhibits a linear current-voltage response, proving that it only has resistive characteristics and no synaptic-like ability.

[0094] In the description of this specification, the references to terms such as "one embodiment," "another embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0095] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A memristor, characterized in that, The memristor includes a glass cone and a polyelectrolyte structure located on the inner wall of the glass cone; The glass cone has a first end opening and a second end opening arranged opposite to each other, the diameter of the first end opening being smaller than the diameter of the second end opening, and the polyelectrolyte structure being located on the inner wall of the first end opening.

2. The memristor according to claim 1, characterized in that, The materials forming the polyelectrolyte structure include polyvinyl imidazole salts.

3. The memristor according to claim 1, characterized in that, The memristor satisfies at least one of the following conditions: The diameter of the first end opening is 0.1~15 micrometers; The thickness of the polyelectrolyte structure is 100~500 nm; In the extending direction of the glass cone sidewall, the ratio of the extension length of the polyelectrolyte structure to the diameter of the first end opening is greater than or equal to 10.

4. A method for preparing the memristor according to any one of claims 1-3, characterized in that, The method includes: A glass cone is provided, the glass cone having a first end opening and a second end opening disposed opposite to each other, the diameter of the first end opening being smaller than the diameter of the second end opening; A polyelectrolyte structure is formed on the inner wall of the first end opening of the glass cone.

5. The method according to claim 4, characterized in that, The formation of the polyelectrolyte structure includes: immersing the first end opening of the glass cone in an initiator solution for impregnation, then adding a catalyst and vinylimidazole monomer to carry out a reaction, thereby forming a polyelectrolyte structure on the inner wall of the glass cone.

6. The method according to claim 5, characterized in that, The initiator is 2-bromo-2-methyl-N-[3-(triethoxysilyl)propyl]propionamide; The immersion treatment time is 8-15 hours; The initiator solution is an acetonitrile solution containing an initiator; In the initiator solution, the mass fraction of the initiator is 3-7%; The reaction further includes: after the impregnation treatment, washing the glass cone sequentially with acetonitrile, ethanol and water, and then adding a catalyst and vinylimidazole monomer.

7. The method according to claim 5, characterized in that, The vinylimidazole monomer is composed of a cation and an anion, wherein the cation includes at least one of 1-vinyl-3-ethylimidazole cation, 1-vinyl-3-butylimidazole cation, and 1-vinyl-3-octylimidazole cation, and the anion includes Cl... - ,Br - BF4 - PF6 - At least one of; The vinylimidazole monomer is added in the form of a vinylimidazole monomer solution, wherein the solvent of the vinylimidazole monomer solution includes at least one of water, ethanol, and DMF; and the mass ratio of the vinylimidazole monomer to the solvent in the vinylimidazole monomer solution is 1:(15~25). The catalyst comprises cuprous bromide and pentamethyldiethylenetriamine.

8. The method according to claim 7, characterized in that, The molar ratio of the vinylimidazole monomer, the cuprous bromide and the pentamethyldiethylenetriamine is (95~105):(3~7):(13~17). The reaction was carried out under oxygen-free and nitrogen-protected conditions; The reaction temperature is 65~75℃, and the reaction time is 20~30h.

9. An artificial synaptic device, characterized in that, include: The memristor according to any one of claims 1 to 3 or the memristor prepared by the method according to any one of claims 4 to 8.

10. The artificial synaptic device according to claim 9, characterized in that, The artificial synapse device further includes: an internal filling fluid, an external solution, a working electrode, and a reference electrode; The internal filling fluid fills the glass cone in the memristor, the first end opening of the glass cone is immersed in the external solution, at least a portion of the working electrode is in contact with the internal filling fluid, and at least a portion of the reference electrode is in contact with the external solution. The internal filling fluid and the external solution are independently selected from at least one of NaCl, NaBF4, NaClO4, KCl, KBF4, and KClO4; The concentrations of the internal filling solution and the external solution are independently selected from 0.1 mmol / L to 1 mol / L.

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