A three-terminal electrochemical device for simulating biological signals

Abstract

The present invention relates to the technical field of electrochemical devices, and provides a three-terminal electrochemical device for simulating biological signals. The device includes a gate, a source, and a drain electrode. There is an electrolyte between the source and drain electrodes and the gate electrode, and there is a channel between the source and drain electrodes. The device materials satisfy the following conditions: (1) The channel material can reversibly adsorb and desorb ions, and embed and extract ions, accompanied by a change in the energy band structure of the channel material; (2) When the regulation signal is greater than the threshold corresponding to the signal, the channel resistance decreases; when the regulation signal is less than the threshold, the channel resistance increases; such that two electrochemical processes with different time synchronization and asymmetric intensities occur between the source and drain electrodes, thereby realizing the simulation of electrical signals in living organisms (especially within neurons and between neurons).

Description

Technical Field

[0001] The present invention relates to the technical field of electrochemical devices, and particularly to a three-terminal electrochemical device for simulating biological signals. Background Art

[0002] Modern computers are largely based on field effect transistor (FET) technology. The basic components of a computer mainly include computing chips (such as CPU / GPU), dynamic random access memory (DRAM), flash memory (such as NAND flash), etc., all of which are composed of large-scale integrated FETs. The FET structure includes a source electrode, a drain electrode, a gate electrode, and a channel, and is a three-terminal semiconductor device that uses the field effect to control the density of majority carriers in the current path to control the channel current. In the FET, the gate electrode is equivalent to the control electrode (base), the source electrode is equivalent to the emitter, and the drain electrode is equivalent to the collector. The gate voltage will regulate the channel between the source and drain electrodes to switch between two resistance states, high and low, so as to achieve the binary state switching of "on / off" or "1 / 0". Different from this, the human brain shows the characteristics of analog signals with multi-level continuous state switching during the decision-making or learning process, that is, it has multiple quasi-continuous states, and it is relatively difficult to simulate this with traditional binary switching devices. For example, assuming that a neuron can switch between 256 distinguishable states, 8 independent devices are required to simulate such a neuron with binary switching devices.

[0003] In order to obtain a stronger and more intelligent computing system, neural network algorithms have gradually attracted attention and begun to play an increasingly important role in fields such as big data processing and artificial intelligence. Performing brain-like simulation or neural network computing through traditional transistor devices with binary switching is a very difficult and low-energy-efficient solution. Therefore, more and more recent research has focused on neuromorphic devices, that is, a class of devices that can simulate electrical signals in living organisms (especially neurons). The electrical signal characteristics of such devices have a high degree of compatibility with neural network algorithms and can switch between multiple continuous resistance states, so they can be used for more energy-efficient neural network computing. Some existing literature has reported devices with a three-terminal structure similar to that of FETs, which can simulate electrical signals in living organisms (especially neurons) through electrochemical processes.

[0004] In the prior art, some devices with a three-terminal structure similar to FETs have emerged, which can simulate electrical signals in living organisms (especially neurons) through an electrochemical process. In a living organism, when a stimulation signal reaches a nerve cell, the cell first generates a graded potential as a response to the signal. The graded potential is a local response potential that rapidly decays over time and distance, and thus is a potential located locally at the synapse. The generation of the graded potential includes two types of processes: depolarization and hyperpolarization, corresponding to whether the graded potential is higher or lower than the resting membrane potential of the cell membrane, respectively reflecting local excitation or inhibition of the nerve cell. However, these two types of processes do not occur simultaneously, that is, the graded potential generated by a stimulation signal is either depolarized or hyperpolarized. After the graded potential continues to increase, the cell will generate an action potential, and the generation of the action potential represents the excitation of the cell. Different from the graded potential, a complete action potential always includes both depolarization and hyperpolarization processes: the cell first rapidly depolarizes, making the membrane potential higher than the resting potential, and then enters hyperpolarization, where the membrane potential is lower than the resting potential, and finally slowly returns to the resting potential.

[0005] However, existing biological signal simulation devices (such as neuromorphic devices) mainly simulate graded potential signals in living organisms, and there are no devices that can simulate action potentials yet. Moreover, since neuromorphic devices mainly use one phenomenon to regulate electrical signals on the channel, in the "non-electrical signal - sensor - neuromorphic device" data stream, for the same non-electrical signal, if one wants to achieve an effect opposite to the regulation effect corresponding to this electrical signal, at least one of the sensor or the neuromorphic device needs to be replaced. This makes the integration of such neuromorphic devices lack flexibility in application fields such as edge computing and robotics, and their applications are limited.

[0006] Therefore, there is an urgent need to develop an electrochemical device that can flexibly and simply simulate the action potential signals of living organisms. Summary of the Invention

[0007] In view of the above problems, a three-terminal electrochemical device for simulating biological signals is proposed to overcome the above problems or at least partially solve the above problems.

[0008] One object of the present invention is to provide a three-terminal electrochemical device for simulating biological signals that can simulate the action potential signals of living organisms.

[0009] A further object of the present invention is to enhance the high integration performance and voltage control stability of the three-terminal electrochemical device.

[0010] Another further object of the present invention is to achieve the output of multiple different response signals under the same regulation signal.

[0011] In particular, according to one aspect of the embodiments of the present invention, a three-terminal electrochemical device for simulating biological signals is provided, comprising:

[0012] a source electrode, a drain electrode, and a gate electrode;

[0013] a channel disposed between the source electrode and the drain electrode; and

[0014] an electrolyte disposed between the source electrode, the drain electrode, and the gate electrode;

[0015] wherein the materials of the channel and the gate electrode are selected such that:

[0016] the material of the channel can reversibly adsorb and desorb ions in the electrolyte, and can reversibly embed and extract ions in the electrolyte accompanied by a change in the energy band structure of the channel material;

[0017] the electrode potential difference x between the gate electrode and the channel is less than 0, and when the control signal applied between the gate electrode and the source electrode is greater than the specified signal threshold, the resistance change ΔR of the channel caused by the embedding or extraction of ions in the electrolyte is less than 0; when the control signal is less than the specified signal threshold, the ΔR is greater than 0; wherein, when the control signal is a voltage control signal, the specified signal threshold is x; when the control signal is a current control signal, the specified signal threshold is 0; so that

[0018] a single control signal causes the following two asynchronous and opposite-phenomenon processes to occur in the channel: the charging and discharging processes of the asymmetric double layer caused by the adsorption and desorption of the ions and the metal-insulator transition process of the channel material caused by the embedding and extraction of the ions, thereby achieving asynchronous channel electrical signal enhancement and suppression effects through a single control signal to simulate biological signals.

[0019] Optionally, the material of the channel includes Li 4+k Ti5O 12 (0 ≤ k ≤ 3).

[0020] Optionally, the material of the gate electrode includes Li + source material or Na + source material.

[0021] Optionally, the Li + source material includes one or more of metallic lithium, pre-lithiated graphite, Li-Si alloy, Li-Al alloy, Li-Au alloy, and the positive electrode material of a lithium-ion battery;

[0022] the Na +The source material includes one or more of metallic sodium, sodium alloy, and the cathode material of a sodium-ion battery.

[0023] Optionally, the material of the channel includes a conductive additive.

[0024] Optionally, the conductive additive includes one or more of carbon nanotubes, graphene, reduced graphene oxide, carbon black, graphite, and titanium particles.

[0025] Optionally, the materials of the source electrode and the drain electrode are conductive materials that do not react with the ions in the electrolyte under the regulation signal.

[0026] Optionally, the electrolyte is a conductor of the ions that can cause a metal-insulator transition of the channel material, but not a conductor of electrons.

[0027] Optionally, the electrolyte is a gel electrolyte, a liquid electrolyte, or a solid electrolyte.

[0028] Optionally, the three-terminal electrochemical device further includes:

[0029] a substrate, on which other structures of the device are directly or indirectly formed; and

[0030] the substrate is made of an insulating material and does not undergo a redox reaction with the electrolyte and / or the gate electrode within the range of the regulation signal.

[0031] The three-terminal electrochemical device for simulating biological signals provided by the present invention has the following advantages compared with the prior art:

[0032] (1) In the three-terminal electrochemical device of the present invention, two mutually independent regulation processes can coexist in a single regulation, namely, the reversible adsorption-desorption of ions (hereinafter referred to as phenomenon A) and the reversible insertion-extraction of ions (hereinafter referred to as phenomenon B), and the regulation effects of the two are opposite and the effect maintenance times are different. That is to say, the three-terminal electrochemical device of the present invention can induce two coexisting, temporally asynchronous, and opposite-effect phenomena through a single regulation signal. This enables the device to obtain signal characteristics that evolve over time. For example, under appropriate measurement conditions, phenomena A and B appear successively in chronological order and the effects compete with each other. This regulation mechanism is very similar to the physical basis for generating action potentials in living organisms. Therefore, this device can successively exhibit enhanced and inhibitory regulation results in a single regulation, and thus can simulate complex bioelectric signals, especially action potential signals in living organisms. However, the performance of existing devices (such as electrochemical nerve-mimicking devices) is always unidirectional, that is, for a single regulation, either an enhanced effect or an inhibitory effect appears, so they are only limited to the simulation of graded potentials and are powerless to simulate complex bioelectric signals.

[0033] (2) For a specific regulatory signal (such as the gate voltage V GS ), the three-terminal electrochemical device of the present invention can give opposite regulatory results: either the enhancement effect dominates or the inhibition effect dominates. This is because the device of the present invention can change the influence ratio of phenomena A and B on the channel electrical signal through measurement conditions: when the measurement current is large enough, the device shows a regulatory result dominated by phenomenon B; when the measurement current is small enough, the device shows a regulatory result dominated by phenomenon A; and the regulatory results of A and B are opposite, thus giving opposite regulatory results. This property enables the device of the present invention, when applied to in-situ analysis of sensor signals, intelligent robots, etc., to change the regulatory direction of the environmental signal on the device without replacing the device in the circuit only by adjusting the reading parameters, which has great flexibility. For existing electrochemical neuromorphic devices, especially those using materials such as LiCoO2, only by changing the regulatory signal V GS can the signal be enhanced or inhibited. This is because the regulatory results of phenomena A and B existing in these existing devices are in the same direction, so the direction of the regulatory result cannot be changed by changing the ratio between the two. In practical applications of these existing devices, especially when applied to in-situ analysis of sensor signals, intelligent robots, etc., since the upstream regulatory signal (such as the output end of a photoelectric sensor, a thermoelectric sensor, a pressure-electric sensor, etc.) is often given, the regulatory effect is also given and cannot be changed. If the effect is to be changed, at least one of the sensor and the neuromorphic device needs to be replaced, which greatly limits their applications.

[0034] (3) Due to the existence of advantage (1), a time dimension can be introduced into the system where the three-terminal electrochemical device of the present invention is located, that is, when the device is applied, the result it gives (if applied in a computing system, it gives a computing result; if applied in a sensing system, it gives a response result to the signal to be measured) can change with time. Specifically, when the obtained result is quantified as Res, the sign (such as positive or negative) and the absolute value of ΔRes are both functions of time t, and the function here is not a constant function.

[0035] (4) Compared with common two-terminal devices (such as memristors), the three-terminal electrochemical device of the present invention can achieve decoupling of the regulatory signal (such as the gate voltage V GS , the gate current I GS ) and the read signal between the source and the drain, which is beneficial to improving the accuracy and linearity of phenomenon B in regulation. In two-terminal devices, the regulatory signal and the read signal are in the same circuit and are prone to interference with each other. For example, although in some applications of LiCoO2 or Li4Ti5O 12In the two-terminal devices made of the material, there also exists a physical mechanism of metal-insulator transition (also known as conductor-insulator transition). However, the specific process relied on by the two-terminal devices is metal-insulator phase separation, which is different from the phase transition of the uniform channel material in the three-terminal devices. At the same time, the metal-insulator phase separation process will be interfered by the read signal and even regulated by the read signal itself (especially the read signal of current type), which will reduce the controllability of the device. More importantly, the two-terminal devices cannot form the asymmetric electric double layer effect between the source and the drain, so there is no A phenomenon as a regulation means, and it is even more impossible to achieve the performance of mixed regulation of A and B phenomena of the device of the present invention.

[0036] (5) The three-terminal electrochemical device of the present invention can not only simulate action potential, but also simulate graded potential. When the measured current or voltage between the channels is large, the aforementioned A phenomenon can disappear within a very short time (for example, less than 3 times the duration of the regulation signal). At this time, the device of the present invention almost only exhibits the B phenomenon: electrochemically induced metal-insulator transition, so that the electrical signal of the channel simply increases or decreases, representing excitatory or inhibitory graded potential.

[0037] (6) The three-terminal electrochemical device of the present invention can simulate both volatile processes and non-volatile processes. When the measured current or voltage between the channels is small, the influence of the A process will be much greater than that of the B process (for example, the amplitude difference of the regulation of the channel electrical signal between the A and B processes can be greater than 1000%). And the A process is a volatile process. At this time, the device as a whole presents a volatile process (for example, the maintenance time of the regulation result is less than 50 times the regulation time). When the measured current or voltage between the channels is large, the regulation effect of the A process quickly disappears, while the B process is an electrochemically induced metal-insulator transition process, and its maintenance ability is longer than that of the A process: for example, it can be greater than 100 times the regulation time, and in a protective atmosphere (or when the device is in a non-protective atmosphere, but the device package can effectively block the penetration of reactive gases in the atmosphere), it can be greater than 1000 times the regulation time. At this time, it can be considered that the device as a whole presents a non-volatile process.

[0038] (7) The three-terminal electrochemical devices of some embodiments of the present invention further adopt Li 4+k Ti5O 12 as the channel material. Li 4+ k Ti5O 12 The material has the following advantages: (a) When the conductor-insulator transition occurs during the insertion and extraction of lithium, the lattice parameter changes by 0.2%, so the strain is extremely small; (b) In the material, Ti 4+ / Ti 3+The redox potential is relatively low; (c) The reversibility of the conductor-insulator transition of the material is very good, and during the cycling process of the phase transition, the crystal stability is much better than the relevant channel materials used in other devices; (d) Since the electrochemical reaction of lithium deintercalation / insertion is a two-phase reaction, the chemical potential difference is a constant, and the reaction occurs on a voltage plateau. Thus, the device of the present invention has the following corresponding advantages: (i) The device can be highly integrated, especially 3D integration, because the extremely small volume expansion will not generate stress on the surrounding devices; (ii) The regulation potential of the device is relatively low, so it has an advantage in terms of regulation power consumption among devices of the same type; (iii) Compared with devices using other channel materials, it has a long service life and a low failure rate; (iv) Compared with devices using other channel materials, the regulation voltage of this device is fixed and easy to control.

[0039] (8) The three-terminal electrochemical device of the present invention does not necessarily need to be fabricated by microfabrication means and has a certain cost advantage in non-large-scale integration application scenarios.

[0040] (9) The three-terminal electrochemical device of the present invention can be flexible and has a wider range of application scenarios.

[0041] (10) The three-terminal electrochemical device of the present invention can form a parallel structure, that is, N (an integer of N≥2) three-terminal electrochemical devices are connected in parallel by sharing a gate electrode or by connecting their respective gate electrodes through wires. In particular, the read signals of multiple parallel devices can be made different. Since the read signal has a significant influence on the proportion of phenomena A and B in the channel signal, when multiple devices in the parallel structure receive exactly the same regulation signal, they will produce different responses, thereby realizing the output of multiple different response signals under the same regulation signal. However, the devices in the parallel structure composed of existing devices can only make exactly the same response when receiving exactly the same regulation signal.

[0042] The above description is only an overview of the technical solution of the present invention. In order to be able to understand the technical means of the present invention more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features and advantages of the present invention more obvious and understandable, the specific embodiments of the present invention are hereinafter specifically exemplified.

[0043] Those skilled in the art will understand the above and other purposes, advantages and features of the present invention more clearly according to the following detailed description of the specific embodiments of the present invention in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the following detailed description of the preferred embodiments. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present invention. Also, throughout the drawings, the same reference numerals are used to represent the same components. In the drawings:

[0045] Figure 1 FIG. is a schematic structural diagram of a three-terminal electrochemical device for simulating biological signals according to an embodiment of the present invention;

[0046] Figure 2 FIG. is a top view structural diagram of a three-terminal electrochemical device for simulating biological signals according to another embodiment of the present invention;

[0047] Figure 3 FIG. is a schematic diagram of a substrate and a mask structure in a three-terminal electrochemical device for simulating biological signals according to Embodiment 1 of the present invention;

[0048] Figure 4 FIG. is a schematic diagram of a substrate and an electrode structure in a three-terminal electrochemical device for simulating biological signals according to Embodiment 1 of the present invention;

[0049] Figure 5 FIG. shows the test results of a three-terminal electrochemical device for simulating biological signals according to Embodiment 1 of the present invention simulating an action potential signal, where the inset is a schematic diagram of an action potential in a living body;

[0050] Figure 6 FIG. shows the regulation test results of a three-terminal electrochemical device for simulating biological signals according to Embodiment 1 of the present invention under the action of two opposite stimulation signals, where one stimulation signal is -0.6 V and lasts for 1 second, and the other stimulation signal is -3.0 V and lasts for 1 second;

[0051] Figure 7 FIG. shows the regulation test results of a three-terminal electrochemical device for simulating biological signals according to Embodiment 1 of the present invention under two different working modes, where the regulation signals are the same in both modes and the regulation effects are opposite;

[0052] Figure 8 FIG. is a schematic diagram of a substrate and an electrode structure in a three-terminal electrochemical device for simulating biological signals according to Embodiment 2 of the present invention;

[0053] Figure 9 FIG. is a comparison diagram of the regulation test results of two devices according to Embodiment 7 of the present invention under the action of exactly the same stimulation signals;

[0054] Figure 10 FIG. shows the regulation test results of the device according to Embodiment 8 of the present invention under the action of a stimulation signal. Detailed Embodiments

[0055] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided so that the present disclosure can be more thoroughly understood and the scope of the present disclosure can be fully conveyed to those skilled in the art.

[0056] In a living organism, when a stimulus signal reaches a nerve cell, the cell first generates a graded potential in response to the signal. This is a local response potential that rapidly decays over time and distance, and is thus a potential located locally at the synapse. The generation of the graded potential includes two types of processes: depolarization and hyperpolarization, corresponding to whether the graded potential is higher or lower than the resting membrane potential of the cell membrane, respectively reflecting local excitation or inhibition of the nerve cell. It should be noted that the two types of processes in the graded potential do not occur simultaneously, that is, the graded potential generated by a single stimulus signal is either depolarized or hyperpolarized.

[0057] However, the graded potential is only the cell's initial response to the signal, and its physiological significance is mainly to induce the generation of an action potential. After the graded potential continues to increase, the cell will generate an action potential, and the generation of the action potential represents the excitation of the cell. Different from the graded potential, a complete action potential always includes two processes: depolarization and hyperpolarization: the cell first rapidly depolarizes, making the membrane potential higher than the resting potential, and then enters hyperpolarization, where the membrane potential is lower than the resting potential, and finally slowly returns to the resting potential. Moreover, the action potential can propagate without attenuation within the cell, thereby spreading excitability throughout the cell membrane and further affecting the behavior of the entire cell in the excited state, and thus can serve as a switch for the relevant physiological activities of the entire cell.

[0058] On the one hand, current biological signal simulation devices (such as neuromorphic devices) can only simulate the graded potential in a living organism. As a simulation of the graded potential, after such a device receives a regulatory signal (corresponding to the stimulus signal) from the gate electrode (functioning the same as in an FET), it causes an increase or decrease in the corresponding electrical signal (corresponding to the graded signal) in the channel to simulate local excitation or inhibition of a nerve cell. Devices and corresponding mechanisms for simulating the graded potential show preliminary neural network computing capabilities, but currently there are no neuromorphic devices that can simulate action potentials. Because a complete action potential always includes two opposite processes: depolarization and hyperpolarization, and this requires the neuromorphic device to be able to achieve two processes with opposite phenomena and asynchronous timing through a single regulation, which poses a huge challenge to the design and preparation of the device.

[0059] On the other hand, current neuromorphic devices mainly use one phenomenon to regulate the electrical signal on the channel, making the integration of such devices in application fields such as edge computing and robotics lack flexibility and the application is limited.

[0060] In view of the above problems, an embodiment of the present invention provides a three-terminal electrochemical device for simulating biological signals. It has a three-terminal structure similar to that of a FET and can simulate a complete action potential, thus providing new possibilities for the development and application of neural mimicking devices.

[0061] Figure 1 FIG. shows a schematic structural diagram of a three-terminal electrochemical device for simulating biological signals according to an embodiment of the present invention. Figure 2 FIG. shows a top view structural diagram of a three-terminal electrochemical device for simulating biological signals according to another embodiment of the present invention, where the dashed line indicates the components covered by the upper components when viewed from above. Refer to Figure 1 and Figure 2 As shown in and, the three-terminal electrochemical device provided by the embodiment of the present invention generally includes a source electrode 2, a drain electrode 3, a gate electrode 6, a channel 4 disposed between the source electrode 2 and the drain electrode 3, and an electrolyte 5 disposed between the source electrode 2 and the drain electrode 3 and the gate electrode 6 (specifically, between the source electrode and the gate electrode and between the drain electrode and the gate electrode).

[0062] In the three-terminal electrochemical device of the embodiment of the present invention, the materials of the channel 4 and the gate electrode 6 are selected as follows: the material of the channel can reversibly adsorb and desorb ions in the electrolyte, and can reversibly embed and extract ions in the electrolyte while accompanied by a change in the energy band structure of the channel material; and, the electrode potential difference between the gate electrode and the channel (i.e., the equilibrium potential of the electrochemical reaction between the gate electrode and the channel material, specifically the difference between the gate potential and the channel material potential) x is less than 0, and when the control signal applied between the gate electrode and the source electrode is greater than the specified signal threshold, the resistance change ΔR (i.e., the difference between the changed resistance and the pre-changed resistance) of the channel caused by the embedding or extraction of ions in the electrolyte is less than 0; when the control signal is less than the specified signal threshold, ΔR is greater than 0, where, when the control signal is a voltage control signal (i.e., the gate voltage V GS ), the specified signal threshold is x, and when the control signal is a current control signal (i.e., the gate current I GS ), the specified signal threshold is 0. When the channel material and the gate electrode material meet the above conditions, a single control signal can cause the following two asynchronous and opposite-phenomenon processes to occur in the channel 4: the charging and discharging processes of the asymmetric double layer caused by the adsorption and desorption of ions and the metal-insulator transition process of the channel material caused by the embedding and extraction of ions, thereby realizing asynchronous channel electrical signal enhancement and suppression effects through a single control signal to simulate biological signals. The biological signals here may include the graded potential signals, action potential signals, etc. mentioned above.

[0063] In other words, in the embodiments of the present invention, the channel material, gate electrode material, and device design in the three-terminal electrochemical device for simulating biological signals need to meet the following conditions (1) and (2).

[0064] (1) The channel material can reversibly adsorb and desorb ions in the electrolyte, and this process is simply referred to as the A process (which can also be called the A phenomenon); at the same time, the channel material can reversibly embed and extract ions in the electrolyte, and this is accompanied by a change in the energy band structure of the channel material, and this process is simply referred to as the B process (which can also be called the B phenomenon).

[0065] Here, the A process is the first electrochemical process on which device regulation depends, corresponding to the regulation of the channel electrical signal by the asymmetric double layer. The B process is the second electrochemical process on which device regulation depends, corresponding to the regulation of the channel electrical signal by the metal-insulator transition of the channel material. The A and B processes always occur simultaneously during the device regulation process, but the proportion of their contributions to the change in the channel electrical signal can vary.

[0066] (2) Let the electrode potential difference between the gate electrode material and the channel material be x, and it is required that x < 0. And if the resistance change of the channel material due to the embedding and extraction of ions in the electrolyte is ΔR, then the channel material must satisfy: when the regulation signal is greater than the threshold of the corresponding signal, ΔR < 0; when the regulation signal is less than the threshold, ΔR > 0.

[0067] For example, when the regulation signal is the gate voltage (V GS ), if V GS > x, then ΔR < 0; if V GS < x, then ΔR > 0.

[0068] For another example, when the regulation signal is the gate current (I GS ), if I GS > 0, then ΔR < 0; if I GS < 0, then ΔR > 0.

[0069] Of course, conversely, if y is defined as the electrode potential difference between the channel material and the gate electrode material (that is, the difference between the channel material potential minus the gate potential), then it is required that y > 0. And when the regulation signal is the gate voltage (V GS ), if V GS > -y, then ΔR < 0; if V GS < -y, then ΔR > 0.

[0070] The above conditions (1) and (2) actually mean that the regulation effects caused by the two electrochemical processes A and B will be reversed, and the following will specifically explain this.

[0071] First, the state of the three-terminal electrochemical device for simulating biological signals in the embodiments of the present invention at rest is examined as follows:

[0072] On the one hand, the channel material is in the initial resistance state, denoted as R0. The instrument for measuring the channel is in the constant current mode, and the output is I SD , and obviously its reading is V SD = R0×I SD = V SD-B-0 , where V SD-B corresponds to the voltage between S-D (i.e., source-drain) caused by phenomenon B, and the subscript 0 represents the initial state / quiescent state.

[0073] On the other hand, the potential difference between the gate electrode and the drain electrode is z; the potential difference between the gate electrode and the source electrode is less than z, which is z-V SD-B-0 . Due to the existence of voltages z and z-V SD-B-0 , at this time, two electric double layers will be formed on the source electrode, the channel surface near the source electrode, the drain electrode, and the channel surface near the drain electrode due to the adsorption of anions and holes. Let the amount of adsorbed holes be Vac 源 and Vac 漏 , then Vac 漏 , Vac 源 are respectively positively correlated with the absolute values of voltages z and z-V SD . Note that Vac 源 ≠Vac 漏 , so there is a set of asymmetric electric double layers between the source and the drain, and this set of asymmetric electric double layers is in the equilibrium state EDL0. It should be noted that EDL0 only marks the charged state of the above-mentioned asymmetric electric double layer of the device, which is completely described by Vac 源 , Vac 漏 , and is completely determined by z and z-V SD .

[0074] Next, consider the state of the three-terminal electrochemical device for simulating biological signals in the embodiment of the present invention at the next moment after the regulation signal V GS ends. Let's assume that V GS > x.

[0075] Due to the regulation of V GS , ions are embedded or extracted from the channel material, changing its energy band. At this time, the resistance R1 of the channel material is lower than the initial state. The voltage generated due to the existence of the measurement constant current source is V SD-B-1 = R1×I SD < V SD-B-0 . At this time, the embedding or extraction of ions causes the channel electrical signal V SD to decrease, which is called the inhibitory regulation of V SD . Since the potential barriers for the embedding and extraction of ions into the solid phase are relatively high and the spontaneous reaction rate is extremely low, this regulation can be maintained for a long time without relaxing to the initial state.

[0076] Meanwhile, due to the regulation of V GS , the two electric double layers in the asymmetric electric double layer are discharged. At this time, the phenomena of ion intercalation and deintercalation in the channel material are not considered. Let's assume that V SD-B remains unchanged. After discharging, the potential difference between the gate electrode and the drain electrode is z + a, and the potential difference between the gate electrode and the source electrode is z - V SD-B + b. Due to the asymmetry of the measurement circuit, it can be found that a > b > 0. At this time, since the absolute values of z + a and z - V SD-B + b change compared with the absolute values of z and z - V SD-B , the asymmetric electric double layer between the source and the drain is regulated from the EDL0 state to the EDL1 state, and the voltage on both sides changes from V SD-B to V SD-B + a - b. This voltage consists of two parts, namely V SD-B generated by the constant current passing through the channel resistance R0 and a - b generated by the asymmetric discharge of the two electric double layers. Since a > b, when the channel resistance remains unchanged, the regulation will result in the measured regulated voltage V SD-1 = V SD-B + a - b > V SD-B = V SD . At this time, the phenomenon of ion adsorption and desorption leads to an increase in the channel electrical signal V SD , which is called the enhanced regulation of V SD . Meanwhile, the potential barriers for ion diffusion in the electrolyte and hole diffusion in the channel are very low, and the asymmetric electric double layer will quickly relax from its EDL1 state to the EDL0 state, thus causing this enhanced regulation to disappear relatively quickly.

[0077] In summary of the above two processes, when the channel material meets the aforementioned conditions (1) and (2), two phenomena will occur during a single regulation: ion intercalation - deintercalation and ion adsorption - desorption. They regulate the channel electrical signal in opposite directions and have different maintenance times.

[0078] For other regulation signals, such as the gate current (I GS ), the regulation process of the device is similar to that under V GS , and will not be specifically analyzed here.

[0079] The three - terminal electrochemical device of the embodiment of the present invention applies a type of channel material that satisfies: (1) There is phenomenon A, that is, the reversible adsorption - desorption of ions, which can cause the charge - discharge of the asymmetric double - layer, and the regulation effect disappears relatively quickly; (2) There is phenomenon B, that is, the reversible intercalation - deintercalation of ions, which can cause the metal - insulator transition of the channel material, and the regulation effect disappears relatively slowly; (3) The measured change in the channel electrical signal dV SD = dV SD-A + dV SD-B , where dV SD-AThe voltage change caused by phenomenon A, dV SD-B The voltage change caused by phenomenon B. When dV SD > 0 is regarded as enhancement. When dV SD < 0 is regarded as inhibition. For a certain determined regulation signal, such as V GS , it always satisfies that if dV SD-A > 0, then dV SD-B < 0; if dV SD-A < 0, then dV SD-B > 0, so that the device can achieve two opposite regulation effects. However, the existing devices only utilize one of A and B, or the regulation directions of A and B are the same, and they cannot perform diversified regulation and cannot achieve the performance and effects of the device of the present invention. For example, for a device that uses conductive materials such as Au, Si, Li, carbon, etc. as the gate electrode and uses Li m CoO2 (0 ≤ m ≤ 1) as the channel material, since the electrode potential of Li m CoO2 is higher than that of almost all materials, the electrode potential difference x between the gate electrode material and the channel material in this device is < 0. During regulation, when the gate voltage V GS > x, Li m CoO2 embeds Li + , changing from a conductor to an insulator phase, resulting in ΔR > 0. When the gate voltage V GS < x, Li m CoO2 releases Li + , becoming a conductor phase, ΔR < 0, which does not meet the aforementioned condition (2). Therefore, such devices cannot achieve the performance of the device of the present invention.

[0080] The three-terminal electrochemical device of the embodiment of the present invention can have two mutually independent regulation processes simultaneously in a single regulation, namely the reversible adsorption-desorption of ions and the reversible insertion-extraction of ions, and the regulation effects of the two are opposite and the effect maintenance times are different. That is to say, the three-terminal electrochemical device of the present invention can induce two coexisting, temporally asynchronous, and effect-opposite phenomena through a single regulation signal. Under appropriate measurement conditions, these two phenomena appear successively in chronological order and the effects compete with each other. This regulation mechanism is very similar to the physical basis for generating action potentials in organisms. Therefore, this device can successively present enhancement-type and inhibition-type regulation results in a single regulation, so as to be able to simulate complex bioelectric signals, especially action potential signals in organisms.

[0081] In the three-terminal electrochemical device of the present invention, the source electrode 2, the drain electrode 3, and the gate electrode 6 are all formed of conductive materials.

[0082] In some embodiments of the present invention, the material of the channel 4 preferably may include Li 4+k Ti5O12 (where k is an integer with 0 ≤ k ≤ 3), for example, Li4Ti5O 12 or Li7Ti5O 12 or a mixture of both, etc. Of course, the material of the channel 4 can also include a mixture of them and other materials.

[0083] Particularly preferably, the material of the channel 4 includes Li4Ti5O 12 . Li 4+k Ti5O 12 The material has the following advantages: (a) When the conductor-insulator transition occurs during the insertion and extraction of lithium, the lattice parameter changes by 0.2%, so the strain is extremely small. For other materials where the metal-insulator transition occurs during the insertion and extraction of lithium, such as Si (lattice parameter change > 100%), graphene (lattice parameter change of about 10%), lithium cobaltate (lattice parameter change of 1%), transition metal oxides, etc., all have a large volume change during the conductor-insulator transition. (b) The redox potential of Ti 4+ / Ti 3+ in the material is relatively low. (c) The reversibility of the conductor-insulator transition of the material is very good. The transition from the pure conductor phase to the pure insulator phase and then back to the pure conductor phase is regarded as a cycle, and during the cycle of the phase transition, the crystal stability is much better than that of the relevant channel materials used in other devices, such as graphene, lithium cobaltate, transition metal oxides, etc. (d) Due to the electrochemical reaction of the insertion and extraction of lithium Li4Ti5O 12 +3Li + +3e - =Li7Ti5O 12 is a two-phase reaction, so the chemical potential difference is a constant, and the reaction occurs on a voltage plateau. For other materials where the metal-insulator transition occurs during the insertion and extraction of lithium, such as Si, graphene, lithium cobaltate, transition metal oxides, etc., they are not two-phase reactions, and the potential at which the phase change reaction occurs is continuously changing. Thus, the device of the present invention has the following corresponding advantages: (i) The device can be highly integrated, especially 3D integration, because the extremely small volume expansion will not generate stress on the surrounding devices; (ii) The regulation potential of the device is relatively low, so it has an advantage in regulating power consumption among the same type of devices; (iii) Compared with the devices using other channel materials, the service life is long and the failure rate is low; (iv) Compared with the devices using other channel materials, the regulation voltage of this device is fixed and easy to control.

[0084] When the channel material can undergo the insertion and extraction of Li + reaction, the conductive material of the gate electrode 6 can be the Li + source material. The Li + source material here refers to the material that can reversibly provide Li + or store Li +materials, including but not limited to one or more of metallic lithium, pre-lithiated graphite, Li-Si alloy, Li-Al alloy, Li-Au alloy, all cathode materials for lithium-ion batteries, etc. However, the selected Li + source material still needs to meet the aforementioned basic conditions. If a Li + source material that does not meet the conditions is selected, the performance and effects described in the present invention cannot be achieved.

[0085] When the channel material can undergo deintercalation and intercalation of Na + reactions, the conductive material of the gate electrode 6 can be the Na + source material. The Na + source material can include one or more of metallic sodium and sodium alloys. However, the selected Na + source material still needs to meet the aforementioned basic conditions. If a Na + source material that does not meet the conditions is selected, the performance and effects described in the present invention cannot be achieved.

[0086] Of course, the combination of the channel material and the gate electrode material is not limited to the above combinations.

[0087] The present invention does not limit the crystal form of the channel material. For example, the channel material can be single crystal, polycrystal, amorphous, etc. Preferably, the channel material is single crystal.

[0088] In some embodiments, in order to make the B process of the channel material occur more easily, a specified amount of conductive additive can be added to the channel material. The addition of the conductive additive is beneficial to the occurrence of the electrochemical reaction of the channel material, but it will also increase the leakage current of the channel. Therefore, it needs to be comprehensively considered when designing the device. The addition amount of the conductive additive (denoted by j) can be set according to the actual application situation and requirements. For example, calculated by mass, it can be set as j≥10wt.%, 5wt.%≤j<10wt.%, 3wt.%≤j<5wt.%, j<3wt.%, etc.

[0089] The present invention does not limit the type of the conductive additive. Optionally, the conductive additive can include, but is not limited to, one or more mixtures of carbon nanotubes, graphene, reduced graphene oxide, carbon black, graphite, titanium particles, etc. Preferably, the conductive additive can be carbon nanotubes or reduced graphene oxide.

[0090] The conductive materials of the source electrode 2 and the drain electrode 3 in the three-terminal electrochemical device of the present invention should be matched with the channel material. The present invention does not specifically limit the materials of the source electrode 2 and the drain electrode 3.

[0091] In a preferred embodiment, the conductive materials of the source electrode 2 and the drain electrode 3 are conductive materials that do not react with the ions in the electrolyte 5 under the regulation signal (simply referred to as ion blocking materials). That is, the ion blocking material refers to a type of material that does not react with the ions participating in the regulation process within the regulation voltage range. When the ions for the metal-insulator transition in the channel material are Li + ions, the conductive materials of the source electrode 2 and the drain electrode 3 are Li + blocking materials, including but not limited to metals such as titanium, stainless steel, TiN, etc., which do not react with lithium ions and are not conductors of lithium ions. By using ion blocking materials to form the source and drain electrodes, it is possible to prevent the loss of ions causing the metal-insulator transition outside the channel, ensuring the accuracy and effectiveness of the B process regulation.

[0092] The present invention has no specific limitation on the relative positions of the source electrode, drain electrode, and gate electrode in the three-terminal electrochemical device.

[0093] In some embodiments, the relative positions of the source electrode, drain electrode, and gate electrode may be as Figure 1 shown. The source electrode 2 and the drain electrode 2 are located on the same side of the electrolyte 5 and at least partially covered by the electrolyte 5, while the gate electrode 6 is located on the opposite side of the electrolyte 5. Alternatively, on the premise of ignoring the thickness of the source electrode, drain electrode, and gate electrode, it can also be said that the source electrode 2 and the drain electrode 3 are in the same plane on one side of the electrolyte 5, the gate electrode 6 is outside this same plane, and the electrolyte 5 is between the plane where the gate electrode 6 is located and the plane where the source electrode 2 and the drain electrode 3 are located. This structure is relatively simple and convenient for device preparation.

[0094] In other embodiments, the relative positions of the source electrode, drain electrode, and gate electrode may be as Figure 2 shown. The source electrode 2, the drain electrode 3, and the gate electrode 6 are in the same plane, and there is a gap between the gate electrode 6 and the source electrode 2 and the drain electrode 3. The electrolyte 5 covers at least this gap and at least a part of the source electrode 2, the drain electrode 3, and the gate electrode 6. This layout can reduce the size in the height of the entire device, which is beneficial for integration.

[0095] When using the above materials, a single regulation signal on the gate electrode 6 can cause two different, asynchronous, and opposite-phenomenon processes in the channel material of the device. Using these two processes, the simulation of action potentials is achieved. These two different, asynchronous, and opposite-phenomenon processes are respectively: (A) the charging and discharging of the asymmetric electric double layer; (B) the metal-insulator transition of the channel material, such as Li 4+k Ti5O 12 due to Li +Metal-insulator transition induced by embedding and extraction. Process A is a volatile process that decays and disappears as the regulation disappears; process B is a non-volatile process that can last for a long time. During the operation of the three-terminal electrochemical device of the present invention, processes A and B always have opposite effects on the channel electrical signal (voltage, current, or resistance) under the induction of the same regulation signal: one inhibits the electrical signal, while the other enhances the electrical signal; vice versa. Specifically, when a regulation signal V GS is applied, V SD = V SD-A + V SD-B will change, where V SD-A corresponds to the voltage between S and D caused by phenomenon A, and the changes of V SD-A and V SD-B are independent of each other and are controlled by two different electrochemical processes. For a specific V GS , if V SD-A increases, then V SD-B decreases; if V SD-A decreases, then V SD-B increases.

[0096] The present invention simulates the asynchronous and reverse characteristics of Na + , K + ion currents on the cell membrane during cell excitation through the asynchronous and reverse characteristics of processes A and B, and thus successfully simulates the action potential phenomenon caused by Na + , K + ion currents.

[0097] In some embodiments of the present invention, the electrolyte 5 can be a conductor of ions (such as Li + , Na + , etc.) that can cause the metal-insulator transition of the channel material, but not a conductor of electrons. Optionally, the electrolyte 5 can be a gel electrolyte, a liquid electrolyte, or a solid electrolyte. Preferably, the electrolyte 5 is a gel electrolyte or a liquid electrolyte.

[0098] In addition, the thickness of the electrolyte 5 (denoted as H) can be adjusted according to actual applications, and the present invention does not specifically limit H. For example, H can be set within the following ranges: H ≤ 20 nm, 20 nm < H ≤ 100 nm, 100 nm < H ≤ 1 μm, 1 μm < H ≤ 20 μm, 20 μm < H ≤ 200 μm, 200 μm < H ≤ 1 mm, or H ≥ 1 mm. Preferably, H is set to 100 nm < H ≤ 20 μm.

[0099] Further, the length of the channel 4 (denoted as L) can also be adjusted according to actual applications, and the present invention does not make specific limitations on L. For example, L can be set within the following ranges: L≤5nm, 5nm<L≤50nm, 50nm<L≤1μm, 1μm<L≤100μm, 100μm<L≤500μm, 500μm<L≤1mm, or L≥1mm. Preferably, L is set to 50nm<L≤100μm.

[0100] Of course, the electrode materials, channel materials, and electrolyte materials in the three-terminal electrochemical device of the present invention are not limited to the materials mentioned above, as long as they can meet the following requirements (1)-(6):

[0101] (1) The electrolyte contains cations and anions and is a conductor of these ions rather than an electron conductor. For the convenience of description, an electrolyte containing only one type of cation IC and one type of anion IA is taken as an example below.

[0102] (2) The channel material can reversibly adsorb and desorb IC and IA ions.

[0103] (3) The channel material can reversibly embed and extract IC or IA ions, accompanied by a change in the energy band structure of the channel material.

[0104] (4) The ion adsorption-desorption and embedding-extraction mentioned in requirements (2) and (3) always occur simultaneously during the device regulation process.

[0105] (5) The electrode potential difference x between the gate electrode material and the channel material is <0, and if the resistance change of the channel material due to the embedding and extraction of IC or IA ions is ΔR, then when the regulation signal is greater than the threshold value of the corresponding signal, ΔR<0; when the regulation signal is less than the threshold value, ΔR>0. For example, when the regulation signal is the gate voltage V GS When, if V GS >x, then ΔR<0, if V GS <x, then ΔR>0. Another example, when the regulation signal is the gate current I GS When, if I GS >0, then ΔR<0, if I GS <0, then ΔR>0.

[0106] (6) The source and drain electrode materials do not undergo an electrochemical reaction with IC or IA ions.

[0107] In some embodiments of the present invention, the three-terminal electrochemical device may further include a substrate 1, and other structures of the device are directly or indirectly formed on the substrate 1. The substrate 1 can be made of an insulating material and does not undergo a redox reaction with the electrolyte 5 and / or the gate electrode 6 within the range of the control signal. The substrate 1 can be either a rigid substrate or a flexible substrate, which is selected according to specific needs. For example, when preparing a flexible three-terminal electrochemical device, a flexible substrate can be selected. The material of the substrate 1 may include, but is not limited to, glass, Al2O3, polyimide, polyethylene terephthalate, polymethyl methacrylate, polypropylene, etc.

[0108] In some embodiments, the three-terminal electrochemical device of the present invention can be a flexible device, making its application scenarios more extensive. Here, flexibility means that the device can be repeatedly bent with a certain radius of curvature and can achieve repeatable control performance in both the flat and bent states. For a flexible three-terminal electrochemical device, the following materials are preferably used: the source electrode, drain electrode, and gate electrode materials are flexible conductive materials, including but not limited to one or more of graphene, carbon nanotubes, reduced graphene oxide, and conductive polymers; the electrolyte is a liquid or gel electrolyte; the channel material is a material that meets the aforementioned conditions (1) and (2) (such as Li 4+k Ti5O 12 particles, nanosheets, nanowires, etc.) and a mixture of a conductive additive and a binder. The binder can be graphite oxide, reduced graphite oxide, PVDF (Polyvinylidene Fluoride), CMC (Carboxymethyl Cellulose), PTFE (Polytetrafluoroetylene), etc.

[0109] The three-terminal electrochemical device of the present invention can work independently (i.e., a single device already has complete functions), or can be integrated on a large scale. The present invention does not limit the application form of the device.

[0110] For example, in some embodiments, multiple three-terminal electrochemical devices having the structure of the present invention can form a parallel structure through a common gate electrode, that is, N (an integer of N≥2) three-terminal electrochemical devices of the present invention are connected to form a parallel structure by sharing a common gate electrode or by connecting their respective gate electrodes through wires. In particular, the read signals of multiple parallel devices (i.e., the channel electrical signals output by the devices) can be made different. Since the read signal has a significant influence on the proportion of phenomena A and B in the channel signal, when multiple devices in the parallel structure are subjected to exactly the same control signal, different responses are generated, thereby realizing the output of multiple different response signals under the same control signal. However, the devices in the parallel structure composed of existing devices can only make exactly the same response when receiving exactly the same control signal.

[0111] It should be noted that when the three-terminal electrochemical device of the present invention is working, whether it works alone or in large-scale integration, it should be noted that the regulated voltage thereof shall not exceed the voltage window of the electrolyte, nor shall it exceed the voltage window at which the reversible deintercalation and intercalation of ions in the channel material occur to cause a metal-insulator phase transition, otherwise it will affect the performance and service life of the device.

[0112] Furthermore, based on the same inventive concept, the embodiments of the present invention further provide a preparation method for a three-terminal electrochemical device having the structure described in any of the foregoing embodiments or a combination of embodiments. The preparation method includes the following steps:

[0113] Step 101, preparing source and drain electrodes on a substrate.

[0114] The preparation methods in Step 101 include, but are not limited to, electron beam evaporation deposition, thermal evaporation deposition, atomic layer deposition, magnetron sputtering deposition, chemical vapor deposition, physical adsorption lamination, etc. The materials of the source and drain electrodes are conductive materials. The substrate is a non-conductive material, including polymers, glass, alumina, etc.

[0115] Step 102, preparing a channel region.

[0116] In Step 102, a channel region can be prepared between the source and drain electrodes by methods such as photolithography, electron beam etching, focused ion beam etching, chemical etching, mechanical exfoliation, etc. The channel region refers to the region between the source and drain electrodes that does not contain electrode materials. If the channel region has been formed when preparing the source and drain electrodes, this step is not required.

[0117] Step 103, preparing a channel.

[0118] In Step 103, the channel material can be prepared in the channel region by means such as electron beam evaporation deposition, thermal evaporation deposition, magnetron sputtering deposition, atomic layer deposition, chemical vapor deposition, physical adsorption lamination, etc. to form a channel. In particular, when using the physical adsorption lamination method, the channel material needs to contain a binder.

[0119] Step 104, preparing an electrolyte.

[0120] In Step 104, the electrolyte can be prepared on the source and drain electrodes and the channel by means such as spin coating, drop coating, electron beam evaporation deposition, magnetron sputtering deposition, atomic layer deposition, etc.

[0121] Step 105, preparing a gate electrode.

[0122] In Step 105, the gate electrode can be prepared on the electrolyte by methods such as electron beam evaporation deposition, thermal evaporation deposition, atomic layer deposition, magnetron sputtering deposition, chemical vapor deposition, physical adsorption lamination, etc.

[0123] Optionally, after step 105, step 106 may further be included: encapsulating the device to isolate air.

[0124] The structure of the device prepared by the method of this embodiment (which may be referred to as Structure One) is, for example, as Figure 1 shown.

[0125] A device having a structure as Figure 2 shown (which may be referred to as Structure Two) is prepared in a similar manner, except that the gate electrode is prepared first and then the electrolyte is prepared.

[0126] Specifically, the preparation method of a three-terminal electrochemical device having Structure Two may include the following steps:

[0127] Step 201, preparing source, drain, and gate electrodes on a substrate.

[0128] The preparation methods in step 201 include but are not limited to electron beam evaporation deposition, thermal evaporation deposition, atomic layer deposition, magnetron sputtering deposition, chemical vapor deposition, physical adsorption lamination, etc. The materials of each electrode are conductive materials. The substrate is a non-conductive material, including polymers, glass, alumina, etc.

[0129] Step 202, preparing a channel region.

[0130] In step 202, the channel region can be prepared between the source and drain electrodes by methods such as photolithography, electron beam etching, focused ion beam etching, chemical etching, mechanical peeling, etc. If the channel region has been formed when preparing the source and drain electrodes, this step is not required.

[0131] Step 203, preparing a channel.

[0132] In step 203, the channel material can be prepared in the channel region by means such as electron beam evaporation deposition, thermal evaporation deposition, magnetron sputtering deposition, atomic layer deposition, chemical vapor deposition, physical adsorption lamination, etc. to form a channel. In particular, when using the physical adsorption lamination method, the channel material needs to contain a binder.

[0133] Step 204, preparing an electrolyte.

[0134] In step 204, the electrolyte can be prepared on the source, drain, gate electrodes, and the channel by means such as spin coating, drop coating, electron beam evaporation deposition, magnetron sputtering deposition, atomic layer deposition, etc.

[0135] Optionally, after step 204, step 205 may further be included: encapsulating the device to isolate air (the purpose is to prevent gases such as water, oxygen, and carbon dioxide in the air from reacting with the active part of the device).

[0136] The above has introduced various embodiments of the three-terminal electrochemical device for simulating biological signals and its preparation method according to the present invention. The following illustrates the embodiments of the present invention through specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0137] Example 1

[0138] First, prepare a three-terminal electrochemical device through the following steps:

[0139] 1) Preparation of the insulating substrate

[0140] Place the glass substrate successively in deionized water, acetone, and alcohol, and ultrasonicate for 10 minutes respectively. After drying the alcohol with nitrogen, prepare a mask for the source and drain electrodes on the glass substrate with polyimide. The top view schematic diagram of the mask is as Figure 3 shown, where 13 is the glass substrate and 7 is the polyimide mask.

[0141] 2) Preparation of the source and drain electrodes

[0142] Place the glass substrate in a thermal evaporation device and thermally evaporate to prepare a Ti / Au / Ti electrode, with the thicknesses of the three being 5 nm / 20 nm / 60 nm respectively. Note that 5 nm Ti is used here to increase the adhesion of Au to the substrate, the Au intermediate layer is to increase the conductivity of the electrode, and the top layer Ti serves as an ion blocking layer to prevent the reaction of Au with metal ions. In some embodiments, a single-layer 80 nm Ti electrode is also directly prepared, which does not affect the main performance demonstrated in this example.

[0143] The shape of the electrode after removing the polyimide mask is as Figure 4 shown, where 23 and 33 are Ti / Au / Ti electrodes. The channel region is between the two side electrodes. W is the electrode width and L is the channel length. In this example, the electrode width is 4 mm and the channel length is 100 μm.

[0144] 3) Preparation of the channel material

[0145] Mix Li4Ti5O 12 particles, PVDF, and carbon black evenly in a certain mass ratio, and add N-methylpyrrolidone to prepare a slurry. In this example, the ratio of the three is preferably 18:1:1.

[0146] 4) Preparation of the channel

[0147] Drop 3 μl of the slurry of the above channel material onto the channel region and vacuum dry to remove N-methylpyrrolidone.

[0148] 5) Preparation of electrolyte and gate electrode

[0149] Cover the channel material with the separator and electrolyte of the lithium battery. The electrolyte used in this embodiment is a solution of 1 mol / L LiTFSI (lithium bis(trifluoromethanesulfonyl)imide) in TEGDME (tetraethylene glycol dimethyl ether). Attach the Li / Cu electrode to the electrolyte as the gate electrode.

[0150] 6) Device encapsulation

[0151] Wrap the device with Parafilm in an argon atmosphere for sealing.

[0152] Next, perform the following device tests on the fabricated three-terminal electrochemical device.

[0153] Connect the source-drain electrodes to an external constant current source with a current value of I SD , and continuously monitor the voltage value between the source-drain electrodes. Connect the gate-source electrodes to an external voltage source with a voltage value of V GS . The usage method of the device is as follows: Apply a pulse signal V GS , detect the change in the voltage V SD between the source-drain electrodes. The change relative to the resting potential V SD0 represents the enhancement or inhibition effect. Here, the resting potential V SD0 refers to the stable potential of the device without being regulated by V GS . Enhancement means that the potential is higher than the resting potential, and inhibition means that the potential is lower than the resting potential. In this embodiment, the pulse width of the applied pulse signal is 1 second, and V GS is in the off state for the rest of the time.

[0154] In particular, after applying V GS , the characteristic of V SD first enhancing and then inhibiting is the simulation of the action potential, showing the signal characteristics evolving with time. The device test signal of this embodiment is as shown in Figure 5 , where the schematic diagram is a typical action potential. Since the regulation voltage V GS = -1.0 V is greater than the potential difference -1.5 V between the gate electrode and the drain electrode, desorption of ions and holes occurs in the asymmetric electric double layer and it is rapidly regulated to the EDL1 state, and at this time it is an enhancement regulation; at the same time, lithium ions are embedded in the channel material, and the specific reaction is Li4Ti5O 12 + 3Li + + 3e - = Li7Ti5O 12 , and an insulator (Li4Ti5O 12 ) - conductor (Li7Ti5O 12) Phase transition occurs, and the channel material is regulated from its initial resistance state R0 to a new resistance state R1, where R1 < R0. The regulating voltage V GS After being turned off, the electric double layer relaxes to the EDL0 state, resulting in a rapid decrease in the high channel voltage generated by the regulation. When the electric double layer approaches the equilibrium state EDL0, the voltage decrease caused by the channel resistance state gradually becomes prominent and persists for a period of time.

[0155] In addition to simulating action potentials, the device of this embodiment can also achieve the effects of existing neuromorphic devices, such as simulating graded potentials and excitatory postsynaptic currents. Only by increasing the current I of the external constant current source SD , the device of this embodiment can convert the channel electrical signal simulating the action potential into a channel signal simulating the graded potential without any structural adjustment to the device. This is because although both of the above regulations exist, at this time I SD is very large, and the change in the potential difference ΔV generated by the current flowing through the channel resistance R R is much larger than the change in the potential difference ΔV generated by the asymmetric discharge of the electric double layer EDL . At this time, the effect corresponding to the EDL can be ignored. Such a channel signal is as Figure 6 shown: After being stimulated by an external -0.6V signal, lithium ions are embedded in the channel material, resulting in an insulator-metal phase transition, a decrease in the channel resistance, and a decrease in the measured voltage, showing inhibition; similarly, after being stimulated by an external -3.0V signal, lithium ions are extracted, showing enhancement. It should be noted that although the signals are the same as those of other existing devices, the specific material mechanisms are different. The device of this embodiment relies on the metal-insulator transition that occurs when Li is embedded in the Li4Ti5O 12 material to form the Li7Ti5O 12 material. The specific data is as Figure 6 shown. The device can respond differently to different stimulation signals, including excitatory and inhibitory responses, that is, the channel electrical signal is stronger or weaker than the signal before stimulation.

[0156] Another advantage of the device of this embodiment compared to existing neuromorphic devices is that when embedded or integrated in an actual circuit, especially when using the output signals of force, light, and sound sensors as the regulation signals for the neuromorphic device (which is very common and important in application scenarios such as artificial intelligence robots), without any structural changes to the circuit and without replacing the neuromorphic device or sensor, the stimulation signal can be changed from an inhibitory signal to an excitatory signal or from an excitatory signal to an inhibitory signal. In other existing devices, this can only be achieved by changing the stimulation signal itself (as shown above Figure 6 ). However, in the device of this embodiment, because the two regulation mechanisms it uses are always opposite, by adjusting I SDDepending on the magnitude, the device can switch between being dominated by the ion adsorption-desorption mechanism, the ion insertion-extraction mechanism, or a mixture of the two. The demonstration of this performance is as shown in Figure 7 shown. Specifically, Figure 7 In Figure 7 , the black line represents the regulation mode dominated by the ion insertion-extraction mechanism, which shows inhibition under a -0.6V signal and enhancement under a -2.7V signal. The gray line represents the regulation mode dominated by the ion adsorption-desorption mechanism, and the regulation direction is exactly opposite to that of the black line mode. When the same stimulation signal is sent from the front end (such as a sensor, etc.), only by changing I SD can two completely opposite regulation effects be obtained. This will endow the system with greater flexibility and programmability, which is also a performance never demonstrated by other neuromorphic devices.

[0157] It should be noted that in device testing, in addition to V GS , other signals can also be used, such as I GS . The test procedure is the same, except that the regulation signal changes during testing.

[0158] In summary, the device performance demonstrated in this embodiment, including the switchability of the regulation mechanism and the simulation of action potentials, cannot be achieved by existing technology products.

[0159] Example 2

[0160] First, a three-terminal electrochemical device is prepared through the following steps:

[0161] 1) Preparation of the insulating substrate

[0162] Place the glass substrate in deionized water, acetone, and alcohol successively, and ultrasonicate for 10 minutes each. After drying the alcohol with nitrogen, use electron beam lithography to prepare PMMA (Polymethyl Methacrylate) masks for the source, drain, and gate electrodes on the glass substrate as masks for subsequent thermal evaporation.

[0163] 2) Preparation of the source, drain, and gate electrodes

[0164] Place the glass substrate in a thermal evaporation device and thermally evaporate Ti / Au / Ti electrodes as the substrates for the source electrode, drain electrode, and gate electrode.

[0165] The electrode shape after removing the PMMA mask is as shown in Figure 8 shown. The device is symmetric left and right, where 14 is the insulating substrate, 24 and 34 are Ti / Au / Ti electrodes, and 64 is the substrate of the gate electrode. In this embodiment, the electrode width is 4 mm, the channel length is 100 μm, the gate electrode width is 4 mm, the gate electrode length is 20 mm, and the gate electrode is 100 μm away from the channel. Attach a Li / Cu electrode to 64 as the gate electrode.

[0166] 3) Preparation of channel material

[0167] Mix Li4Ti5O 12 particles, PVDF, and carbon black evenly in a certain mass ratio, and add N-methylpyrrolidone to prepare a slurry. In this example, the mass ratio of the three is preferably 18:1:1.

[0168] 4) Preparation of channel

[0169] Drop 3 μl of the slurry of the above channel material onto the channel area and vacuum dry to remove N-methylpyrrolidone.

[0170] 5) Preparation of electrolyte

[0171] Cover the channel material with a separator and electrolyte of a lithium battery. In this example, the electrolyte used is a TEGDME solution of 1 mol / L LiTFSI.

[0172] 6) Device encapsulation

[0173] Wrap the device with Parafilm in an argon atmosphere for sealing.

[0174] Then, test the fabricated three-terminal electrochemical device. The test method is the same as that in Example 1, and the test results are similar to those in Example 1.

[0175] Example 3

[0176] First, fabricate a three-terminal electrochemical device through the following steps:

[0177] 1) Preparation of insulating substrate

[0178] This step is the same as step 1) in Example 2, except that the insulating substrate is replaced with a 100-plane Si single crystal.

[0179] 2) Fabrication of source, drain, and gate electrodes

[0180] Deposit Ti / Pd / Ti electrodes by electron beam evaporation with thicknesses of 5 nm / 20 nm / 60 nm respectively. In this example, the electrode width is 200 μm, the channel length is 10 μm, the gate electrode width is 200 μm, the gate electrode length is 400 μm, and the gate electrode is 10 μm away from the channel.

[0181] 3) Preparation of channel

[0182] Deposit Li4Ti5O 12 thin film as the channel material on the insulating substrate / electrode obtained in 2) by magnetron sputtering. Li4Ti5O 12The thickness of the thin film is 100 nm. Then, the device is thermally annealed at an annealing temperature of 500 °C to increase the crystallinity of the Li4Ti5O 12 thin film and introduce partial oxygen vacancies.

[0183] 4) Preparation of the electrolyte layer

[0184] The LiPON solid electrolyte thin film is deposited by magnetron sputtering. The thickness of the LiPON thin film is 200 nm.

[0185] 5) Device encapsulation

[0186] A 500-nm-thick Si thin film is deposited by magnetron sputtering as a water and oxygen barrier layer.

[0187] Then, the fabricated three-terminal electrochemical device is tested. The testing method is the same as that in Example 1, and the testing results are similar to those in Example 1.

[0188] Example 4

[0189] First, a three-terminal electrochemical device is fabricated through the following steps:

[0190] 1) Preparation of the insulating substrate

[0191] This step is the same as step 1) in Example 1, except that the insulating substrate is replaced with a 100-μm-thick PET (Polyethylene terephthalate).

[0192] 2) Preparation of the continuous carbon nanotube thin film

[0193] Using a sublimed sulfur / ferrocene mixture as the catalyst and ethanol as the carbon source, a continuous carbon nanotube thin film is grown by the BACVD (Blown Aerosol Chemical Vapor Deposition) method. The thickness of the carbon nanotube thin film in this example is preferably 400 nm.

[0194] 3) Preparation of the source and drain electrodes

[0195] The continuous carbon nanotube thin film is covered on the surface of the substrate and the mask, and then wetted with alcohol. Then, the polyimide mask is removed. The dimensions of the electrodes are the same as those in Example 1, and the average length of the channel is 200 μm.

[0196] 4) Preparation of the channel

[0197] This step is the same as steps 3)-4) in Example 1, except that the mass ratio of Li4Ti5O 12 particles, PVDF, and carbon black is 80:15:5.

[0198] 5) Preparation of the electrolyte layer

[0199] Mix LiClO4, PEO, and succinonitrile in an acetonitrile solution, and the mass ratio is not limited. Spin-coat the mixed electrolyte on the surface of the channel and let it penetrate. Remove the acetonitrile solution by vacuum drying.

[0200] 6) Prepare the gate electrode

[0201] Use the 400-nm carbon nanotube film obtained in step 2 as the gate electrode.

[0202] 7) Device encapsulation

[0203] Spin-coat a 200-nm PMMA layer on the surface of the device, and then cover it with a 15-μm polyimide film.

[0204] Then, perform device testing on the fabricated three-terminal electrochemical device. The testing method is the same as that in Example 1, and the testing results are similar to those in Example 1. Further, the device in this example is a flexible device and can operate normally at a curvature radius greater than 3 cm.

[0205] Example 5

[0206] First, fabricate a three-terminal electrochemical device through the following steps:

[0207] 1) Preparation of the insulating substrate

[0208] This step is the same as step 1) in Example 3, except that the insulating substrate is replaced with a 20-μm-thick polyimide film.

[0209] 2) Preparation of the continuous carbon nanotube / graphene composite film

[0210] Using a sublimed sulfur / ferrocene mixture as the catalyst and ethanol as the carbon source, grow a continuous carbon nanotube film using the BACVD method. The thickness of the carbon nanotube film in this example is preferably 100 nm.

[0211] Cover the continuous carbon nanotube film on the copper surface, and use methane as the carbon source to grow a continuous carbon nanotube / graphene composite film using the CVD method.

[0212] 3) Preparation of the source, drain, and gate electrodes

[0213] Cover the continuous carbon nanotube / graphene composite film on the substrate and the mask surface, and soak it with alcohol. Then remove the PMMA mask. The sizes of the electrodes and the channel are the same as those in Example 3.

[0214] 4) Preparation of the channel

[0215] This step is the same as step 3) in Example 3, except that the thickness of the Li4Ti5O 12 film is 20 nm, and the annealing temperature is changed to 350 °C.

[0216] 5) Preparation of the electrolyte layer

[0217] This step is the same as step 5) of Example 4.

[0218] 6) Device encapsulation

[0219] Spin coat a 200 nm PMMA layer on the device surface, and then cover it with a 15 μm polyimide film.

[0220] Then, perform device testing on the fabricated three-terminal electrochemical device. The testing method is the same as that of Example 1, and the test results are similar to those of Example 1. Further, the device of this example is a flexible device and can operate normally at a curvature radius greater than 5 cm.

[0221] Example 6

[0222] First, fabricate a three-terminal electrochemical device through the following steps:

[0223] 1) Preparation of the insulating substrate

[0224] This step is the same as step 1) of Example 1, except that the mask does not expose the channel region.

[0225] 2) Fabrication of the source and drain electrodes

[0226] Place the glass substrate in a thermal evaporation device and thermally evaporate a 60 nm Ti electrode.

[0227] After removing the polyimide mask, use a scalpel to cut a slit in the conductive 60 nm Ti source and drain electrodes to form the channel region. In this example, the electrode width is 5 mm and the channel length is approximately 200 μm.

[0228] Prepare a mass transfer blocking layer on the electrodes using polyimide.

[0229] 3) Preparation of the channel material

[0230] This step is the same as step 3) of Example 1.

[0231] 4) Fabrication of the channel

[0232] This step is the same as step 4) of Example 1.

[0233] 5) Preparation of the electrolyte and gate electrode

[0234] This step is the same as step 5) of Example 1.

[0235] 6) Device encapsulation

[0236] Place the upper surface of the device under a cover glass and use an ultraviolet-curable glue to seal the gap between the upper and lower surface glass plates of the device.

[0237] Next, device testing was performed on the fabricated three-terminal electrochemical device. The testing method was the same as that in Example 1, and the test results were similar to those in Example 1.

[0238] Example 7

[0239] In this example, the preparation steps of the three-terminal electrochemical device were the same as those in Example 1, except that two devices were fabricated. One device used Al2O3 material as the channel material, and the other device used Li4Ti5O 12 material, and the slurry ratio of the channel material was 38:1:1.

[0240] It should be noted that Al2O3 does not meet the aforementioned conditions (1) and (2) of the present invention. Therefore, only the processes of ion adsorption and desorption can occur on the channel, and the processes of ion insertion and extraction cannot occur. That is to say, the device using Al2O3 channel material actually serves as a comparative example. The regulation data of the two devices fabricated in this example are as Figure 9 shown. Under the premise that the measured current and regulated voltage of both are exactly the same, the electrical signals regulated from the initial state to the new state are significantly different. The device based on Al2O3 has a rapidly decaying enhanced regulation corresponding to the adsorption-desorption process of ions and holes, but there is no sustainable inhibitory regulation and it quickly returns to the resting state. While the device based on Li4Ti5O 12 has a rapidly decaying enhanced regulation and a sustainable inhibitory regulation, corresponding to the adsorption-desorption process of ions and holes and the insertion-extraction process of lithium ions, respectively.

[0241] Example 8

[0242] In this example, the preparation steps of the three-terminal electrochemical device were the same as those in Example 1, except that the gate electrode was a stainless steel / copper electrode. Since the combination of stainless steel (gate electrode material) and lithium titanate (channel material) does not meet the above conditions (1) and (2) of the present invention, the device in this example actually serves as a comparative example.

[0243] The test performance of the device in this example is as Figure 10 shown. The phenomena of A and B in opposite directions cannot be observed, and only the mixed regulation of A and B in the same direction can be observed. Moreover, the electrode potential difference between LTO (lithium titanate) and the stainless steel gate is 0, so a larger voltage (0.6V vs 3.0V) is required for regulation to occur the reaction of lithium ion deintercalation. Compared with Figure 6 it can be found that although the device regulation in this example can still be carried out ( Figure 10), but the amplitude is significantly smaller than that when the lithium metal / copper electrode is used as the gate electrode. Specifically, after the combination of LTO and the lithium gate electrode is regulated by a gate voltage of -0.6V for 1 second, the resistance changes by 22% at 30 seconds and 19% at 60 seconds. After the combination of LTO and the stainless steel gate electrode is regulated by a gate voltage of -3.0V for 1 second, the resistance only changes by 7% at 30 seconds and 4% at 60 seconds. This is because during the regulation, the gate electrode cannot compensate for the lithium ions embedded in the channel in the electrolyte, thus greatly limiting the degree of reaction occurrence, making it difficult for the B phenomenon on which the regulation depends to occur, resulting in a weakened regulation amplitude and an increased energy consumption for device regulation.

[0244] Example 9

[0245] In this example, the preparation steps of the three-terminal electrochemical device are the same as those in Example 1, except that multiple devices are prepared simultaneously, and all devices use the same gate electrode to form a parallel structure with a common gate.

[0246] In this example, multiple parallel devices can be regulated by the same gate electrode signal. In particular, the read signals of multiple parallel devices can be different, so that when they receive exactly the same regulation signal, they produce different responses. This cannot be achieved in the common gate structure composed of other devices.

[0247] Example 10

[0248] In this example, the preparation steps of the three-terminal electrochemical device are the same as those in Example 1, except that the Parafilm used in step 6) is replaced with a continuous graphene-carbon nanotube-Parafilm composite film.

[0249] The preparation method of the continuous graphene-carbon nanotube-Parafilm composite film is as follows: Cover the carbon nanotube film on the copper substrate, grow graphene at high temperature, and the grown graphene and the carbon nanotube film are combined by covalent bonds and van der Waals forces to form a continuous graphene-carbon nanotube film. Cover the obtained film on the Parafilm film, heat it up for bonding and then cool it down to obtain the continuous graphene-carbon nanotube-Parafilm composite film.

[0250] The device sealed in this way has better service performance because the continuous graphene-carbon nanotube film has better waterproof and oxygen permeation resistance.

[0251] Example 11

[0252] In this embodiment, the preparation steps of the three-terminal electrochemical device are the same as those in Embodiment 1, except that in step 5), a continuous graphene-carbon nanotube-Parafilm composite film is further laminated on the Li side of the Li / Cu gate electrode. The preparation method of the continuous graphene-carbon nanotube-Parafilm composite film is the same as that in Embodiment 10.

[0253] The surface of the gate electrode treated in this way is more stable, and the generation of lithium dendrites can be effectively inhibited during the device regulation process, enabling the device to have better service performance.

[0254] Embodiment 12

[0255] In this embodiment, the preparation steps of the three-terminal electrochemical device are the same as those in Embodiment 1, except that the Li / Cu gate electrode used in step 5) is replaced with a Na / Cu gate electrode, and the 1 mol / L LiTFSI TEGDME solution used as the electrolyte is replaced with a 1 mol / L NaPF6 EC solution.

[0256] The combination of the Na gate electrode and the Li4Ti5O 12 channel material in this embodiment of the device also meets the above conditions (1) and (2) of the present invention. Among them, phenomenon A is the same as that described in Embodiment 1 without change; phenomenon B is similar to that described in Embodiment 1, except that the electrochemical reaction it depends on changes from the original Li4Ti5O 12 (insulator) + 3Li + + 3e - = Li7Ti5O 12 (conductor) to 2Li4Ti5O 12 (insulator) + Na + + e - = Li7Ti5O 12 (conductor) + Na6LiTi5O 12 . A metal-insulator transition still occurs before and after the reaction.

[0257] Embodiment 13

[0258] First, prepare a three-terminal electrochemical device through the following steps:

[0259] 1) Preparation of the insulating substrate

[0260] This step is the same as step 1) in Embodiment 2.

[0261] 2) Preparation of the source and drain electrodes

[0262] Deposit a Ti / Pd / Ti electrode by electron beam evaporation, with thicknesses of 5 nm / 20 nm / 60 nm respectively. In this embodiment, the electrode width is 200 μm and the channel length is 10 μm.

[0263] 3) Fabricate the channel

[0264] Use a continuous carbon nanotube film as the channel material. After infiltration with alcohol and then evaporation to dryness, make it adhere to the substrate, source electrode, and drain electrode.

[0265] 4) Fabricate the electrolyte and gate electrode

[0266] Mix LiClO4, PEO, and succinonitrile in an acetonitrile solution, and the mass ratio is not limited. Spin-coat the mixed electrolyte on the surface of the channel and let it penetrate. Remove the acetonitrile solution by vacuum drying. Attach a Li / Cu electrode to the electrolyte as the gate electrode.

[0267] 5) Device encapsulation

[0268] Use magnetron sputtering to deposit a 500-nm-thick Si film as the water and oxygen barrier layer.

[0269] Next, perform device testing on the fabricated three-terminal electrochemical device. The testing method is the same as that in Example 1. The A phenomenon relied on by the device in this example is the same as that in Example 1, and the B phenomenon relied on is similar to that described in Example 1, except that the electrochemical reaction relied on changes from the original Li4Ti5O 12 (insulator) + 3Li + + 3e - = Li7Ti5O 12 (conductor) to: 6C (mixture of conductor and semiconductor) + Li + + e - = LiC6 (conductor). Since the electronic energy levels of the substances before and after the reaction change, resulting in a decrease in resistance from high to low, the phenomenon is the same as that in Example 1, except that the regulation amplitude is different.

[0270] It should be noted that the channel material used in this example is a carbon nanomaterial, and the gate electrode is a lithium metal electrode. The electrode potentials of the two directly determine the performance of the device's A phenomenon. Although carbon nanomaterials, such as graphene, have been used in neuromorphic devices and also rely on 6C (conductor) + Li + + e - = LiC6 (conductor), but these works can only achieve the regulation performance related to the B phenomenon in the present invention. None of the prior arts have noticed the problem of the electrode potential difference between the gate electrode and the channel material. The electrodes they use are LiFePO4 or inert metal electrodes such as Au and Pd, and the electrode potentials of these electrodes do not meet the above condition (2) of the present invention, so the performance of the device of the present invention cannot be achieved.

[0271] In the specification provided herein, a large number of specific details are set forth. However, it will be understood that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been shown in detail so as not to obscure an understanding of the present specification.

[0272] Having now described the invention, it will be apparent to one of ordinary skill in the art that many changes and modifications can be made thereto without departing from the spirit and scope of the invention as set forth herein. Therefore, the scope of the invention should be understood and recognized to cover all such other changes or modifications.

Claims

1. A three-terminal electrochemical device for simulating biological signals, characterized in that Comprising: A source electrode, a drain electrode, and a gate electrode; A channel disposed between the source electrode and the drain electrode; And An electrolyte disposed between the source electrode, the drain electrode, and the gate electrode; Wherein, the materials of the channel and the gate electrode are selected such that: The material of the channel can reversibly adsorb and desorb ions in the electrolyte, and can reversibly embed and extract ions in the electrolyte accompanied by a change in the energy band structure of the channel material; The electrode potential difference x between the gate electrode and the channel is less than 0, and when the control signal applied between the gate electrode and the source electrode is greater than the specified signal threshold, the resistance change ΔR of the channel caused by the embedding or extraction of ions in the electrolyte is less than 0; when the control signal is less than the specified signal threshold, ΔR is greater than 0; wherein, when the control signal is a voltage control signal, the specified signal threshold is x; when the control signal is a current control signal, the specified signal threshold is 0; so that A single control signal causes the following two asynchronous and opposite-phenomenon processes to occur in the channel: the charging and discharging processes of the asymmetric double layer caused by the adsorption and desorption of the ions, and the metal-insulator transition process of the channel material caused by the embedding and extraction of the ions, thereby achieving asynchronous channel electrical signal enhancement and suppression effects through a single control signal to simulate biological signals.

2. The three-terminal electrochemical device according to claim 1, wherein The material of the channel includes Li 4+k Ti5O 12 where (0 ≤ k ≤ 3).

3. The three-terminal electrochemical device according to claim 1, wherein The material of the gate electrode includes Li + source material or Na + source material.

4. The three-terminal electrochemical device according to claim 3, wherein The Li + source materials include one or more of metallic lithium, pre-lithiated graphite, Li-Si alloy, Li-Al alloy, Li-Au alloy, and cathode materials for lithium-ion batteries; The Na + source materials include one or more of metallic sodium, sodium alloys, and cathode materials for sodium-ion batteries.

5. The three-terminal electrochemical device according to claim 1, wherein The material of the channel includes a conductive additive.

6. The three-terminal electrochemical device according to claim 5, wherein The conductive additive includes one or more of carbon nanotubes, graphene, carbon black, graphite, titanium particles.

7. The three-terminal electrochemical device according to claim 6, characterized in that, The graphene includes reduced graphene oxide.

8. The three-terminal electrochemical device according to claim 1, wherein The materials of the source electrode and the drain electrode are conductive materials that do not react with the ions in the electrolyte under the control signal.

9. The three-terminal electrochemical device according to claim 1, wherein The electrolyte is a conductor of the ions that can cause the metal-insulator transition of the channel material, but not a conductor of electrons.

10. The three-terminal electrochemical device according to any one of claims 1, 8, and 9, wherein The electrolyte is a gel electrolyte, a liquid electrolyte, or a solid electrolyte.

11. The three-terminal electrochemical device according to claim 1, wherein Further comprising: A substrate, and other structures of the device are directly or indirectly formed on the substrate; and The substrate is made of an insulating material and does not undergo a redox reaction with the electrolyte and / or the gate electrode within the range of the control signal.

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