Light-emitting electrochemical artificial synapse with parallel output of photoelectric signals and method

Abstract

The application relates to a light-emitting electrochemical artificial synapse with a photoelectric signal parallel output function, which comprises, from bottom to top, a substrate, a bottom electrode, a light-emitting active layer and a top electrode; the light-emitting active layer is composed of a light-emitting material, an ion transmission matrix and a lithium salt; when a continuous voltage pulse is input, the light-emitting material in the active layer and the ion transmission matrix have an electrochemical oxidation-reduction reaction, which causes the gradual increase of the device conductance, and the post-synaptic current is also gradually increased; meanwhile, with the increase of the electron and hole injection, the transient electroluminescence intensity is also gradually increased. The application can simultaneously take the output light signal and the electric signal intensity as the synapse weight, can be used for constructing an optical and electrical hybrid artificial neural network, and provides a brand-new feasible scheme for realizing a neural morphological computing system taking light and electricity as media.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of artificial synapse devices, and particularly relates to a light-emitting electrochemical artificial synapse with a parallel output function of photoelectric signals and a method. BACKGROUND

[0002] With the popularization of the fifth generation wireless system (5G), people generate a large amount of data traffic in daily life, including text, images, audio and video files, which accelerates the development of the big data era. In the face of explosive growth of data information, computers based on the traditional von Neumann framework have been unable to handle complex tasks (such as digital image analysis, speech recognition and intelligent navigation) with low power consumption, while the human brain neural system can simultaneously act as a processor and a memory to learn, remember and calculate a large amount of external information in an efficient and highly parallel manner. The synapse is the basic unit of the human brain neural system.

[0003] In recent years, with the sharp increase of interest in brain-like computing, people have conducted in-depth research on different types of high-performance artificial synapses, including atomic switches, phase change memories, resistive random access memories, memristors, synaptic transistors and the like. However, the current artificial synapse device is generally limited to single output of optical signals or electrical signals. In contrast, the artificial synapse device with simultaneous output of photoelectric signals is a relatively ideal device selection, because it can provide more selectivity for multi-channel signal transmission of artificial neural networks. In addition, the introduction of optical signals is expected to reduce the electronic lead density of very large scale integrated circuits (VLSI) through on-chip optical networks, thereby promoting the development of large-scale optoelectronic hybrid artificial neural networks with low crosstalk and high fault tolerance. SUMMARY

[0004] Therefore, the purpose of the present application is to provide a light-emitting electrochemical artificial synapse with a parallel output function of photoelectric signals and a method, and the obtained light-emitting electrochemical artificial synapse can simulate synaptic plasticity through the output of optical signals and electrical signals at the same time.

[0005] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0006] A light-emitting electrochemical artificial synapse with a parallel output function of photoelectric signals comprises, from bottom to top, a substrate, a bottom electrode, a light-emitting active layer and a top electrode; the light-emitting active layer is composed of a light-emitting material, an ion transport matrix and a lithium salt. When a continuous voltage pulse is input, the light-emitting material in the active layer and the ion transport matrix undergo an electrochemical redox reaction, resulting in a gradual increase in the conductance of the device, and the post-synaptic current also gradually increases. At the same time, with the increase of electron and hole injection, the transient electroluminescence intensity also gradually increases.

[0007] Further, the substrate is made of glass, polyethylene terephthalate or polyimide.

[0008] Further, the material of the bottom electrode is indium tin oxide, silver, aluminum or gold, and the thickness is 100-200 nm.

[0009] Further, the light-emitting active layer is prepared by a spin coating process, and the thickness is 150-550 nm.

[0010] Further, the light-emitting material is an organic light-emitting polymer material.

[0011] Further, the ion transport matrix is an organic ion exchange resin.

[0012] Further, the material of the top electrode is indium tin oxide, aluminum, gold or silver, and the thickness is 50-100 nm.

[0013] A preparation method of a light-emitting electrochemical artificial synapse with parallel output function of photoelectric signals, comprising the following steps:

[0014] S1. Organic light-emitting polymer, organic ion exchange resin and lithium salt solution are blended to prepare a light-emitting active layer solution;

[0015] S2. After the substrate with a bottom electrode is cleaned, the light-emitting active layer solution is deposited on the substrate by a spin coating process in a nitrogen-filled environment and annealed to form a light-emitting active layer;

[0016] S3. A top electrode is prepared on the light-emitting active layer obtained in step S2 by a thermal evaporation method to obtain a light-emitting electrochemical artificial synapse with parallel output function of photoelectric signals.

[0017] Further, the water and oxygen content in the nitrogen environment for spin coating to prepare the light-emitting active layer film and annealing is less than 0.1 PPm.

[0018] Compared with the prior art, the present application has the following beneficial effects:

[0019] The present application can simulate the plasticity of synapses by simultaneously outputting photoelectric signals from a single synapse device, and can provide more selectivity for multi-channel signal transmission of artificial neural networks. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of the light-emitting electrochemical artificial synapse with parallel output function of photoelectric signals of embodiment 1 of the present application;

[0021] Figure 2 It is an excitatory postsynaptic current (EPSC) diagram of the light-emitting electrochemical artificial synapse provided in embodiment 1 of the present application;

[0022] Figure 3 A light-emitting electrochemical artificial synapse excitatory postsynaptic light intensity (EPSI) plot provided for Example 1 of the present application;

[0023] Figure 4 A paired-pulse facilitation (PPF) plot of light-emitting electrochemical artificial synapse current output provided for Example 1 of the present application;

[0024] Figure 5 A paired-pulse facilitation (PPF) plot of light-emitting electrochemical artificial synapse light intensity output provided for Example 1 of the present application;

[0025] Figure 6 A long-term potentiation (LTP) plot of light-emitting electrochemical artificial synapse current output provided for Example 1 of the present application;

[0026] Figure 7 A long-term potentiation (LTP) plot of light-emitting electrochemical artificial synapse light intensity output provided for Example 1 of the present application;

[0027] Figure 8 A spike-rate dependent plasticity (SRDP) plot of light-emitting electrochemical artificial synapse current output provided for Example 1 of the present application;

[0028] Figure 9 A spike-rate dependent plasticity (SRDP) plot of light-emitting electrochemical artificial synapse light intensity output provided for Example 1 of the present application;

[0029] In the figure: 100 - substrate, 110 - bottom electrode, 120 - light-emitting active layer, 130 - top electrode. DETAILED DESCRIPTION

[0030] The present application is further described below in conjunction with the accompanying drawings and examples.

[0031] Please refer to Figure 1 The present application provides a light-emitting electrochemical artificial synapse with parallel output of photoelectric signals, as shown in Figure 1 from bottom to top in order are substrate 100, bottom electrode 110, light-emitting active layer 120, and top electrode 130. The light-emitting active layer is composed of organic light-emitting polymer, organic ion exchange resin, and lithium salt. When a continuous voltage pulse is input, electrochemical oxidation-reduction reaction occurs between the light-emitting material and the ion transport matrix in the active layer, resulting in gradual increase of the device conductance and also gradual increase of the postsynaptic current; at the same time, with the increase of electron and hole injection, the transient electroluminescence intensity is also gradually enhanced.

[0032] Preferably, in the present embodiment, the substrate material is glass, polyethylene terephthalate or polyimide; the bottom electrode material is indium tin oxide, silver, aluminum or gold; and the light-emitting active layer is deposited by a spin-coating process. Its thickness is 150-550 nm. The material used for the top electrode is indium tin oxide, gold, aluminum or silver, and its thickness is 50-100 nm.

[0033] Example 1

[0034] 1) Cleaning of the indium tin oxide glass substrate: The indium tin oxide patterned glass substrate is sequentially ultrasonically cleaned with a glass cleaner, isopropyl alcohol, ethanol and deionized water for 15 minutes, and the cleaned glass is dried with nitrogen for standby use.

[0035] 2) Preparation of poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene], polyethylene oxide and lithium triflate solution: 10 mg of poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene], 10 mg of polyethylene oxide and 10 mg of lithium triflate are added to 1 ml of chloroform, 1 ml of cyclohexanone and 1 ml of cyclohexanone respectively, and stirred with a magnetic stirrer at 50 degrees Celsius for 16 hours. After completion of stirring, 10 mg / ml of poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene], 10 mg / ml of polyethylene oxide and 10 mg / ml of lithium triflate solution are obtained.

[0036] 3) Preparation of poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene], polyethylene oxide and lithium triflate mixed solution: On the basis of step two, 10 mg / ml of poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene], 10 mg / ml of polyethylene oxide and 10 mg / ml of lithium triflate solution are blended in a volume ratio of 1:0.25:0.03, and stirred with a magnetic stirrer at 50 degrees Celsius for 2 hours. After completion of stirring, poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene], polyethylene oxide and lithium triflate mixed solution are obtained.

[0037] 4) In a nitrogen-filled environment, the mixed solution prepared in step 3) is spread on the patterned indium tin oxide glass substrate cleaned in step 1) using a pipette, and then the solution is formed into a uniform film on the substrate using a spin-coating speed of 1400 rpm (40 s), and the substrate is annealed at 88 degrees Celsius for 10 minutes in a nitrogen-filled environment to form a light-emitting active layer;

[0038] 5) A 2 cm long and 2 mm wide 80 nm thick silver electrode is evaporated on the glass substrate obtained in step 4) using a special mask by vacuum thermal evaporation.

[0039] Example 2

[0040] 1) Cleaning of ITO glass substrate: The ITO patterned glass substrate was cleaned with glass cleaner, isopropyl alcohol, ethanol and deionized water for 15 minutes each by ultrasonic cleaning. The cleaned glass was dried by nitrogen gas and ready for use.

[0041] 2) Preparation of poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene], polyethylene oxide and lithium triflate solution: 10 mg of poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene], 10 mg of polyethylene oxide and 10 mg of lithium triflate were added into 1 ml of chloroform, 1 ml of cyclohexanone and 1 ml of cyclohexanone respectively and stirred by magnetic stirrer at 50 degree Celsius for 16 hours. After completion of stirring, 10 mg / ml of poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene], 10 mg / ml of polyethylene oxide and 10 mg / ml of lithium triflate solution were obtained.

[0042] 3) Preparation of poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene], polyethylene oxide and lithium triflate mixed solution: On the basis of step two, 10 mg / ml of poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene], 10 mg / ml of polyethylene oxide and 10 mg / ml of lithium triflate solution were blended in the volume ratio of 1:0.25:0.03 and stirred by magnetic stirrer at 50 degree Celsius for 2 hours. After completion of stirring, poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene], polyethylene oxide and lithium triflate mixed solution were obtained.

[0043] 4) The mixed solution prepared in step 3) was spread on the patterned ITO glass substrate cleaned in step 1) using a pipette under a nitrogen filled environment, then a uniform film was formed on the substrate by spin coating at 1400 rpm (40 s) and the substrate was annealed at 88 °C for 10 min under a nitrogen filled environment to form a light emitting active layer;

[0044] 5) A 2 cm long and 2 mm wide 80 nm thick gold electrode was deposited on the glass substrate obtained in step 4) by vacuum thermal evaporation using a special mask.

[0045] The prepared light-emitting electrochemical artificial synapse with parallel output of photoelectric signals is subjected to corresponding electrical and optical tests to simulate biological synaptic plasticity. A pulse voltage with an amplitude of 6 V is applied between the bottom electrode and the top electrode, the top electrode is regarded as the postsynaptic membrane, the light-emitting active layer is regarded as the synaptic gap, and the bottom electrode is regarded as the presynaptic membrane. The output light intensity and current (conductance) of the device are measured and regarded as the weight of the synapse. The light-emitting electrochemical artificial synapse successfully simulates excitatory postsynaptic current and light intensity (EPSC and EPSI) (as shown in Figure 2 、 Figure 3 ), double-pulse facilitation (PPF) of current output and light intensity output (as shown in Figure 4 、 Figure 5 ), long-term potentiation (LTP) of current output and light intensity output (as shown in Figure 6 、 Figure 7 ), and pulse-dependent rate plasticity (SRDP) of current output and light intensity output (as shown in Figure 8 、 Figure 9 ).

[0046] The above merely describes preferred embodiments of the present application, and any equivalent changes and modifications made within the scope of the patent application of the present application shall fall within the scope of the present application.

Claims

1. A light-emitting electrochemical artificial synapse having a parallel output function of photoelectric signals, characterized by comprising: a light-emitting electrochemical cell; and a photoelectric conversion element connected to the light-emitting electrochemical cell. The device comprises, from bottom to top, a substrate, a bottom electrode, a light-emitting active layer and a top electrode; the light-emitting active layer is composed of a light-emitting material, an ion transport matrix and a lithium salt; when a continuous voltage pulse is input, the light-emitting material in the active layer and the ion transport matrix undergo electrochemical redox reaction, resulting in gradual increase of the device conductance and gradual increase of the post-synaptic current; meanwhile, with the increase of electron and hole injection, the transient electroluminescence intensity is also gradually enhanced; The substrate is made of glass, polyethylene terephthalate or polyimide; The material of the bottom electrode is indium tin oxide, silver, aluminum or gold, and the thickness is 100-200 nm; The light-emitting material is an organic light-emitting polymer material; The ion transport matrix is an organic ion exchange resin; The material of the top electrode is indium tin oxide, aluminum, gold or silver, and the thickness is 50-100 nm.

2. The artificial synapse with photoelectric signal parallel output function according to claim 1, wherein, The light-emitting active layer is prepared by spin coating process, and the thickness is 150-550 nm.

3. The method of producing a light-emitting electrochemical artificial synapse with parallel output of photoelectric signals according to claim 1 or 2, characterized by, The method comprises the following steps: S1. Blending an organic light-emitting polymer, an organic ion exchange resin and a lithium salt solution to prepare a light-emitting active layer solution; S2. After washing the substrate with a bottom electrode, the light-emitting active layer solution is deposited on the substrate by spin coating process in a nitrogen-filled environment and annealed to form a light-emitting active layer; S3. The top electrode is prepared on the light-emitting active layer obtained in step S2 by thermal evaporation method to obtain a light-emitting electrochemical artificial synapse with parallel output function of photoelectric signal.

4. The method of claim 3, wherein the method further comprises the step of: 5 applying a voltage to the photoelectronic signal parallel output function of the artificial synapse. The water and oxygen content in the nitrogen environment for spin coating to prepare the light-emitting active layer film and annealing is less than 0.1 PPm.

Images