A neural synapse biomimetic device based on ion-doped polymer electrolyte

Abstract

The application discloses a nerve synapse biomimetic device based on ion-doped high-molecular electrolyte. The biomimetic device uses a negatively charged high-molecular electrolyte as a functional layer and realizes a resistance change performance by doping positive charged metal ions. The biomimetic device comprises a lower electrode layer, a medium layer composed of a negative high-molecular electrolyte thin film layer based on ion doping and having a negative charge group in a main chain prepared on the lower electrode layer, and an upper electrode layer above. The lower electrode layer comprises a substrate and a first electrode layer above the substrate; the upper electrode layer is a second electrode layer. The negative high-molecular electrolyte thin film based on ion doping is prepared by a spin coating method. The nerve synapse biomimetic device has the advantages of low cost of used materials, large-area film preparation, fast and simple preparation process, good size reducibility, simple resistance change mechanism, preparation into a full-transparent device or a flexible device, low-power-consumption simulation of nerve synapse functions and the like.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of nerve synapse bionic devices, in particular to an ion-doped polymer electrolyte nerve synapse bionic device. BACKGROUND

[0002] With the rise of neuromorphic computing, the simulation of the plasticity of nerve synapses, which are important parts for performing learning and memory functions, has attracted more and more attention. Among numerous electronic devices, a memristor is an attractive device for a bionic synapse device because a simple sandwich structure can replace a set of complex circuits to realize a basic learning function, and the device has advantages such as simplified manufacturing process, fast operation speed and convenient three-dimensional stacking. However, the memristor currently applied to the bionic synapse device still has some problems, such as that the high and low resistance states of the device are affected by the size, and the storage density is low; and the resistance change mechanism is complex and greatly different from the working principle of a biological synapse. Therefore, exploring a memristor with high storage density and simple resistance change mechanism has become a key to the development of a nerve synapse bionic device.

[0003] A polyelectrolyte is a water-soluble polymer material, and the side chain of the structural unit contains an ionizable group. When the polyelectrolyte is dissolved in water, the ionizable group is partially ionized to generate a polyion and a low-molecular ion with opposite charges, and has good conductivity. The ion-doped polymer electrolyte nerve synapse bionic device disclosed by the application has resistance transition occurring in a partial region of the material, and the resistance transition is completed through repeated formation and rupture of an ion conduction path in the polymer electrolyte layer, so that the low resistance value of the device is not related to the size of the device, and therefore, the device has good scalability and improved storage density. Meanwhile, the resistance change mechanism of the device is relatively simple and easy to analyze. The ion-doped polymer electrolyte nerve synapse bionic device disclosed by the application is first proposed, and no related report has been found at home and abroad. SUMMARY

[0004] The application aims to solve the problems of the current nerve synapse bionic device based on a memristor in terms of size scalability and working principle, and proposes a novel nerve synapse bionic device with simple material, multi-value storage, good size scalability and simple mechanism. The device is capable of changing the medium layer material between different resistance states through a suitable pulse stimulation signal, and thus simulates the function of a nerve synapse.

[0005] The technical scheme of the application is as follows:

[0006] A nerve synapse biomimetic device based on ion-doped polymer electrolyte comprises: a lower electrode layer, a negative charge polymer electrolyte thin film layer prepared on the lower electrode layer, and an upper electrode layer located above the negative charge polymer electrolyte thin film layer; the negative charge polymer electrolyte thin film layer is an ion-doped negative charge polymer electrolyte thin film layer, the negative charge polymer electrolyte is a polymer electrolyte with negative charge groups on the main chain, including but not limited to one of polyacrylic acid or poly 4-styrene sulfonic acid; the concentration of the doping ions is the same as the molar concentration of the negative charge polymer electrolyte, and the type of the doping ions is an alkali metal solution, including but not limited to one of calcium chloride or sodium chloride.

[0007] The lower electrode layer comprises a substrate and a first electrode layer located above the substrate; and the upper electrode layer is a second electrode layer.

[0008] Optionally, the substrate can be a commonly used substrate such as a silicon wafer, glass, PET or PI.

[0009] Optionally, the thickness of the lower electrode layer and the upper electrode layer is 50-500 nm.

[0010] Optionally, the thickness of the polymer electrolyte thin film layer is 10-30 nm.

[0011] Advantages and beneficial effects of the present application

[0012] The present application provides a nerve synapse biomimetic device based on ion-doped polymer electrolyte. The present application uses ion-doped polymer electrolyte as a resistive switching functional layer. Under the action of different polar voltages, the repeated formation and rupture process of the conductive path of the doping ions in the polymer electrolyte layer makes the device switch between different resistance states. There are multiple stable states in the resistance change process, and each state has good retention characteristics. At the same time, when the stimulating voltage is repeatedly applied, the resistance can be well switched between multiple states; the device resistance value can be continuously and slowly increased or decreased, thereby well simulating the related functions of nerve synapses; the device has low cost, simple preparation process, good size reducibility, simple resistive switching mechanism, and biocompatibility, and has broad application prospects. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 A structure schematic diagram of a nerve synapse biomimetic device based on ion-doped polymer electrolyte provided by the present application;

[0014] Figure 2 A structure schematic diagram of a nerve synapse biomimetic device based on ion-doped polymer electrolyte provided by the present application in low resistance and high resistance states.

[0015] Figure 3The I-V curve diagram actually measured of the device prepared by using the ITO transparent electrode as the electrode layer is provided for the embodiment of the present application.

[0016] Figure 4 The high-low resistance value and reading time curve diagram in the continuous change process of the resistance actually measured of the device prepared by using the ITO transparent electrode as the electrode layer is provided for the embodiment of the present application.

[0017] Figure 5 The I-V curve diagram in the continuous change process of the resistance actually measured of the device prepared by using the ITO transparent electrode as the electrode layer is provided for the embodiment of the present application. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present application will be apparently and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative labor fall within the protection scope of the present application.

[0019] In order to make the above objectives, characteristics and advantages of the present application more apparent, comprehensible and easier to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0020] Embodiment 1

[0021] Figure 1 The structural schematic diagram of the ion-doped high-molecular electrolyte-based neural synapse biomimetic device is provided for the embodiment of the present application.

[0022] Referring to Figure 1 , the ion-doped high-molecular electrolyte-based neural synapse biomimetic device of the embodiment comprises a lower electrode layer 3, a high-molecular electrolyte thin film layer 2 doped with metal positive ions deposited on the lower electrode layer 3, and an upper electrode layer 1 located above the ion-doped high-molecular electrolyte thin film layer 2; the lower electrode layer 3 comprises a substrate 3-2 and a first electrode layer 3-1 located above the substrate 3-2; the upper electrode layer 1 is a second electrode layer.

[0023] As an optional embodiment, the substrate in the embodiment is one of commonly used substrates such as a glass substrate, a silicon wafer, PET or PI.

[0024] As an optional embodiment, the thickness of the first electrode layer 3-1 and the second electrode layer in the embodiment is 80-500 nm.

[0025] As an optional embodiment, the thickness of the ion-doped polymer electrolyte thin film layer 2 is 10-80 nm. The performance is basically the same within the above thickness requirement range.

[0026] As an optional embodiment, the concentration of the doped metal ions is in proportional relationship with the negative charged functional groups of the polymer electrolyte.

[0027] The principle of the ion-doped polymer electrolyte nerve synapse biomimetic device is as follows:

[0028] When no voltage is applied to the ion-doped polymer electrolyte nerve synapse biomimetic device, the distribution of the doped ions in the thin film layer is discrete, and the first electrode layer and the second electrode layer are not connected, and the device is in a high resistance state. After the voltage is applied, the doped ions move directionally under the action of the electric field and the ion channel formed by the negative charged polymer electrolyte, and finally form a metal ion channel between the first electrode layer and the second electrode layer, and the device is in a low resistance state. As shown in Figure 2 , wherein Figure 2 part (a) of Figure 2 is a high resistance state diagram in the case of ion channel rupture, Figure 3 part (b) of Figure 4 is a low resistance state diagram in the case of ion channel formation. Under the action of the applied electric field, the biomimetic device undergoes a transition between the high and low resistance states (as shown by the change of the I-V curve in Figure 5 ), and both the high and low resistance states have long-term sustainability (as shown in ). In addition, the resistance of the biomimetic device also has a plurality of intermediate states between the high and low resistance states, and can continuously change between the plurality of states under the stimulation of the voltage (as shown by the change of the I-V curve in

[0029] ). The above process is extremely similar to the performance of neurotransmitters in synapses, and therefore the nerve synapse biomimetic device can simulate the plasticity of neurons.

[0030] The polymer electrolyte has various types, low cost, good flexibility, simple film preparation, good film forming property and the like, and has great development potential in the direction of flexible electronic devices. Meanwhile, the release of neurotransmitters and the modulation of synaptic weights in chemical synapses depend largely on ions in cells. The embodiment will take the ion-doped polymer electrolyte film layer as the resistance change function layer, under the action of an applied electric field, can simulate the function of biological synapses, there are multiple stable states in the resistance change process and all have good retention characteristics, at the same time, when the pulse voltage is repeatedly applied, the resistance can well change between multiple states; the neural synapse device has simple structure, low power consumption and advantages such as flexibility and transparency, which provides a foundation for the development of nerve synapse biomimetic devices based on organic materials; can promote researchers to build efficient and low-energy neural morphological computing to overcome the limitations of traditional von Neumann architecture; the device has low cost, simple preparation process, good size reducibility, simple resistance change mechanism and biocompatibility, and has broad application prospect.

[0031] The principles and implementation manners of the present application are described by applying specific examples in the present application, and the above embodiment is only used to help understand the method of the present application and its core idea; meanwhile, for those skilled in the art, according to the idea of the present application, the specific implementation manners and application ranges will be changed. In summary, the content of the specification should not be understood as a limitation of the present application.

Claims

1. An ion-doping-based polymer electrolyte-based neurosynaptic biomimetic device, comprising: a lower electrode layer, a negative-charge polymer electrolyte thin film layer deposited on the lower electrode layer, and an upper electrode layer above the negative-charge polymer electrolyte thin film layer; the lower electrode layer comprises a substrate and a first electrode layer above the substrate; the upper electrode layer is a second electrode layer; characterized in that, The negative charge polymer electrolyte thin film layer is a negative charge polymer electrolyte thin film layer which has been ion doped, the concentration of the doped ions is the same as the molar concentration of the negative charge polymer electrolyte, the type of the doped ions is alkali metal ions, including but not limited to one of calcium chloride or sodium chloride.

2. The ion-doped, high-molecular-weight electrolyte-based neurosynaptic biomimetic device of claim 1, wherein, The negative charge polymer electrolyte is a polymer electrolyte with negative charge groups on the main chain, including but not limited to one of polyacrylic acid or poly 4-styrene sulfonic acid.

3. The ion-doped, high-molecular-weight electrolyte-based neurosynaptic biomimetic device of claim 1, wherein, The substrate is a substrate commonly used in the semiconductor manufacturing industry, including but not limited to a rigid substrate silicon wafer or glass, a flexible substrate PET or PI.

4. The ion-doped, high-molecular-weight electrolyte-based neurosynaptic biomimetic device of claim 1, wherein, The thin film thickness of the lower electrode layer and the upper electrode layer is 50-500 nm.

5. The ion-doped, high-molecular-weight electrolyte-based neurosynaptic biomimetic device of claim 1, wherein, The thickness of the negative charge polymer electrolyte thin film layer is 10-30 nm.

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