Organic artificial photoelectric synapse device and preparation method thereof
By adopting a vertical phase separation preparation method in photoelectric synaptic devices, the blending deposition of photosensitive semiconductor materials and insulating polymers is solved, and organic artificial photoelectric synaptic devices with high stability and excellent performance are achieved.
Patent Information
- Application Number
- CN202411765414.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-04
- Publication Date
- 2025-03-21
AI Technical Summary
The existing organic semiconductor materials show significant performance degradation during long-term use due to their sensitivity to oxygen and moisture in photoelectric synaptic devices, which limits the practical application potential of the device.
Through the vertical phase separation preparation method, photosensitive semiconductor materials are blended with insulating polymers to form a vertical phase separation structure to prepare high-stability organic artificial photoelectric synaptic devices. The specific steps include sequentially providing an insulating dielectric layer, a modification layer, a source-drain electrode, a photosensitive charge transport layer and a device packaging layer on the substrate, and preparing the active layer and a packaging layer through thin film transfer.
The preparation of high-stability organic artificial photoelectric synaptic devices is achieved, which avoids the destruction of the underlying semiconductor by non-orthogonal solvents, improves the optical response and electrical performance of the device, and has good application prospects.
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Figure CN119677294A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of optoelectronic synapse devices, and in particular relates to an organic artificial optoelectronic synapse device and a preparation method thereof. Background Art
[0002] In the era of the Internet of Things and big data, how to store and process massive amounts of information at the same time is becoming an urgent problem. With the explosive growth of information, computing systems based on the traditional "von Neumann architecture" are gradually facing challenges such as high energy consumption, slow computing speed, and small data processing capacity due to their physically independent memory and central computing units. The human brain, as the most complex organ in the body, receives information from a huge neural sensory network and controls the body's reactions every day, such as simple pronunciation, walking, and more difficult learning and thinking. At the same time, synapses are an important part of the human brain's information processing. Therefore, it is of great significance to simulate the way the human brain processes information by constructing artificial synapses.
[0003] So far, various types of synaptic devices have been prepared, such as two-terminal memristors, three / multi-terminal transistors, etc., which can successfully simulate the basic functions of synapses. Among them, phototransistor devices have a high degree of integration and can modulate synaptic behavior and achieve signal amplification through gates in biomimetic synapse simulations, showing great advantages. Organic semiconductor materials are widely used in artificial photoelectric synaptic devices due to their highly customizable molecular structure and adjustable carrier transport. However, a major challenge in the application of organic semiconductor materials in photoelectric synaptic devices is their air stability. Due to the inherent sensitivity of organic semiconductors to oxygen and moisture, these materials often show significant performance degradation during long-term use, which greatly limits the practical application potential of photoelectric synaptic devices.
[0004] Therefore, it is crucial to develop organic optoelectronic synaptic devices with a single active layer and high air stability. Summary of the invention
[0005] The technical problem to be solved by the present invention is to address the deficiencies of the prior art and provide a method for preparing a highly stable organic artificial optoelectronic synapse device by vertical phase separation, wherein a vertical phase separation structure is produced by co-deposition of a photosensitive semiconductor material and an insulating polymer; an active layer and an encapsulation layer of the optoelectronic synapse device are prepared by a thin film transfer step, thereby achieving the preparation of a highly stable organic artificial optoelectronic synapse device.
[0006] In order to solve the above technical problems, the present invention discloses an organic artificial photoelectric synaptic device, the synaptic device comprising a substrate 1 and an insulating dielectric layer 2, a modification layer 3, a source-drain electrode 4, a photosensitive charge transport layer 5 and a device encapsulation layer 6 sequentially arranged on the substrate 1;
[0007] The photosensitive material used in the photosensitive charge transport layer 5 is P3HT-b-PPI (5F); the insulating polymer used in the device encapsulation layer 6 is polymethyl methacrylate (PMMA);
[0008] Preferably, the P3HT-b-PPI (5F) has a synaptic-like behavior to green light. The PPI segment in the block copolymer provides a charge trapping site, and P3HT provides charge transport.
[0009] The photosensitive charge transport layer 5 and the device encapsulation layer 6 are prepared in one step by a mixed thin film vertical phase separation method.
[0010] Wherein, the substrate 1 is a Si substrate; the insulating dielectric layer 2 is a SiO2 layer; the modified layer 3 is a CYTOP layer; and the source-drain electrode 4 is an Au electrode.
[0011] The present invention also provides a method for preparing an organic artificial photoelectric synapse device, which specifically comprises the following steps: spin coating CYTOP as a modification layer on a cleaned Si / SiO2 substrate, then thermally evaporating Au onto the CYTOP modification layer through a shadow mask to prepare a source-drain electrode, and then contacting the photosensitive charge transport layer of the blended film with the source-drain electrode. At this time, the semiconductor material layer of the blended film is in direct contact with the electrode to form an active layer of the device, while the insulating polymer layer located above forms an effective encapsulation of the device, thereby finally preparing the organic artificial photoelectric synapse device.
[0012] Wherein, the thickness of the SiO2 layer in the Si / SiO2 substrate is 300nm.
[0013] Wherein, the channel length and width of the source-drain electrode are 100 μm and 1000 μm respectively.
[0014] The spin coating parameters of the modified layer are: speed 3000 rpm, duration 40 seconds; the shadow mask thermal evaporation thickness of the source-drain electrode is 50 nm.
[0015] Among them, the preparation steps of the blended film are as follows: spin coating a mixed solution of P3HT-b-PPI (5F) and PMMA onto a pre-prepared Si / PVA substrate, and peeling off after drying to obtain a vertically phase-separated blended film. In this process, a photosensitive semiconductor material is blended with an insulating polymer and then deposited on a hydrophilic substrate. After deposition, the blended film forms a vertically phase-separated structure, in which the insulating polymer is located in the lower layer and the semiconductor material occupies the upper layer.
[0016] The solvent of the mixed solution of P3HT-b-PPI (5F) and PMMA is dichlorobenzene, the concentration of P3HT-b-PPI (5F) in the mixed solution is 1 mg / mL, and the concentration of PMMA in the mixed solution is 3 wt %; the specific parameters of the spin coating are a speed of 2000 rpm and a duration of 60 seconds;
[0017] The Si / PVA substrate is prepared by spin coating a 2 wt % PVA aqueous solution on a Si substrate, wherein the specific parameters of the spin coating are a speed of 4500 rpm and a duration of 40 seconds.
[0018] Beneficial effects: The present invention uses a block copolymer with both carrier transport and capture functions, and prepares the active layer and encapsulation layer of the device in one step through a mixed thin film vertical phase separation method. Compared with depositing an encapsulation layer on a conventional semiconductor, the damage of the underlying semiconductor by a non-orthogonal solvent is avoided. The synaptic transistor device of the present invention has excellent light response performance and electrical performance, and the preparation method is simple and low-cost, and has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments, and the above and / or other advantages of the present invention will become more clear.
[0020] Figure 1 Schematic diagram of the structure of the synaptic transistor device of the present invention, wherein 1 is a substrate; 2 is an insulating dielectric layer; 3 is a modification layer; 4 is a source-drain electrode; 5 is a photosensitive charge transfer unit; 6 is an encapsulation layer;
[0021] Figure 2 is the structural formula of the photosensitive material P3HT-b-PPI(5F) used in the photosensitive charge transport unit in Example 1 of the present invention;
[0022] Figure 3 Schematic diagram of the energy band of the transistor device under green light stimulation in Example 1 of the present invention;
[0023] Figure 4 This is a comparison graph of the change in ΔEPSC over time of the synaptic transistor device in Example 1 of the present invention under 532nm green light stimulation before and after being placed in the air for two weeks. DETAILED DESCRIPTION
[0024] The experimental methods described in the following examples are conventional methods unless otherwise specified; the reagents and materials described are commercially available unless otherwise specified.
[0025] In the following examples, P3HT-b-PPI(5F) (structural formula: Figure 2 The synthetic route of (shown) is as follows:
[0026]
[0027] The specific steps are as follows: inject 2,5-dibromo-3-hexylthiophene monomer into the polymerization tube, and then inject pre-dried THF into the polymerization tube as a solvent. Stir thoroughly in an ice bath at 0°C for 10 minutes, then slowly inject a THF solution of isopropyl magnesium chloride (2.0 mol in THF) into the polymerization tube, and stir thoroughly for two hours to combine isopropyl magnesium chloride with 2,5-dibromo-3-hexylthiophene monomer. Weigh Ni(dppp)Cl2 and add it to the polymerization tube to catalyze the polymerization. Then move the polymerization tube to an oil bath at 35°C and stir for 2 hours. Weigh pentafluorophenyl isocyanate monomer and add it to the polymerization tube and continue heating and stirring for 4 hours. After the reaction is completed, add anhydrous methanol to the polymerization tube to terminate the reaction. Use a high-speed centrifuge to separate the solid and liquid, pour out the liquid, and rinse the centrifuged solid with a small amount of chloroform, then add methanol and centrifuge, and repeat three times. The resulting precipitate is placed in a vacuum drying oven and dried at room temperature to obtain a purple-red P3HT-b-PPI (5F) solid;
[0028] In the following examples, CYTOP (model: CTL-809M) was purchased from AGC Asahi Glass.
[0029] Embodiment 1:
[0030] like Figure 1 As shown, this embodiment provides a synaptic transistor device, specifically, an insulating dielectric layer 2 is arranged on a substrate 1 serving as a gate electrode, a modification layer 3 is arranged on the insulating dielectric layer 2, a source-drain electrode 4 is arranged on the modification layer 3, a vertical phase separation film is arranged on the source-drain electrode 4, a lower layer 5 of the vertical phase separation film is a photosensitive charge transfer layer, and an upper layer 6 of the vertical phase separation film is a device encapsulation layer.
[0031] Specifically, in this embodiment: the substrate 1 serving as the gate electrode is a Si substrate; the insulating dielectric layer 2 is a 300 nm thick SiO2 layer; the modification layer 3 is a CYTOP layer; the source-drain electrode 4 is an Au electrode, and the distance between the two is 100 μm; the photosensitive material used in the photosensitive charge transfer unit of the lower layer 5 of the vertical phase separation film is P3HT-b-PPI (5F); the insulating polymer used in the upper layer 6 of the vertical phase separation film is polymethyl methacrylate (PMMA).
[0032] The synaptic transistor device of this embodiment is manufactured as follows:
[0033] Step 1: Si and Si / SiO2 were cleaned with piranha solution (a mixture of 30% hydrogen peroxide and concentrated sulfuric acid, volume ratio 3:7) and then used for later use; 2wt% polyvinyl alcohol (PVA) aqueous solution was spin-coated on the Si substrate (spin coating parameters: speed 4500rpm, duration 40 seconds) as a sacrificial layer;
[0034] Step 2: Take a silicon wafer with a SiO2 layer on the surface and spin-coat CYTOP on its surface (spin coating parameters are 3000 rpm and 40 seconds) as a modification layer. Then, thermally evaporate Au (thickness of about 50 nm) onto the CYTOP modification layer through a shadow mask to form a source and drain, where the length and width of the channel are 100 μm and 1000 μm respectively;
[0035] Step 3: Dissolve P3HT-b-PPI (5F) and PMMA in dichlorobenzene respectively, and mix to obtain a final concentration of 1 mg / mL P3HT-b-PPI (5F) and 3 wt% PMMA. In a glove box, spin coat the mixed solution on the Si / PVA substrate prepared in step 1 at a speed of 2000 rpm for 60 seconds, and then dry it in a vacuum oven overnight without heating to remove the solvent. Finally, peel off the dried blended film to make it float on the water surface, and then transfer the film so that the photosensitive charge transfer unit on its upper surface contacts Si / SiO2 / CYTOP / Au, finally forming a bottom-gate low-contact synaptic device.
[0036] Mechanism of vertical phase separation of blended films: When the mixed solution is uniformly coated on the surface of a hydrophilic substrate, due to the difference in surface energy, the P3HT-b-PPI(5F) molecular chains with lower surface energy tend to spontaneously migrate to the film / air interface, while on the contrary, the PMMA component with higher affinity to the substrate preferentially aggregates to the substrate interface. This process causes the blended film to delaminate in the vertical direction, eventually forming a double-layer structure.
[0037] The P3HT-b-PPI (5F) photosensitive material of this embodiment is sensitive to 532 nm green light (light intensity of 1.67 mW cm -2 ) have synaptic-like behavior.
[0038] In the absence of light stimulation, a certain voltage is applied to the gate electrode to form a conductive path in the channel between the source and drain electrodes, and then a certain voltage is applied to the drain electrode to make the charges move in a directional manner to form a current. When light is irradiated on the conductive channel between the source and drain electrodes, excitons are generated, and the excitons separate to form photogenerated electrons and holes. Carriers such as electrons and holes move in a directional manner under the action of the electric field between the source and drain electrodes, generating a photocurrent ( Figure 3 ).
[0039] The current reached without light stimulation is the initial dark current; then light stimulation is applied to the photosensitive charge transfer unit, and the current reached is the excitatory postsynaptic current EPSC, and the difference between it and the initial dark current is recorded as ΔEPSC; by testing the change in ΔEPSC before and after the synaptic device is placed in the air for two weeks, the stability of the device's biomimetic synaptic performance is evaluated; Figure 4 As shown, it can be found that compared with the initial state, the ΔEPSC peak value can still be maintained above 90% before and after being placed in the air for two weeks, which proves that the PMMA layer plays a good encapsulation role in the vertical phase separation thin film device.
[0040] In summary, the present invention selects a block copolymer with both carrier transport and capture functions, and produces vertical phase separation by blending with an insulating polymer, thereby preparing the active layer and encapsulation layer of the device in one step. The prepared synaptic device shows high stability in the air.
[0041] The present invention provides an idea of an organic artificial optoelectronic synapse device and a method for preparing the same. There are many methods and approaches to implement the technical solution. The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be considered as the scope of protection of the present invention. All components not specified in this embodiment can be implemented by existing technologies.
Claims
1. An organic artificial optoelectronic synaptic device, characterized in that: The synaptic device comprises a substrate 1 and an insulating dielectric layer 2, a modification layer 3, a source-drain electrode 4, a photosensitive charge transport layer 5 and a device encapsulation layer 6 which are sequentially arranged on the substrate 1; The photosensitive material used in the photosensitive charge transport layer 5 is P3HT-b-PPI (5F); and the insulating polymer used in the device encapsulation layer 6 is polymethyl methacrylate.
2. The synaptic device according to claim 1, characterized in that The photosensitive charge transport layer 5 and the device encapsulation layer 6 are prepared in one step by a hybrid thin film vertical phase separation method.
3. The synaptic device according to claim 1, characterized in that The substrate 1 is a Si substrate; the insulating dielectric layer 2 is a SiO2 layer; the modified layer 3 is a CYTOP layer; and the source-drain electrode 4 is an Au electrode.
4. A method for preparing an organic artificial optoelectronic synapse device, characterized in that: The specific steps are: spin-coating CYTOP as a modification layer on a cleaned Si / SiO2 substrate, then thermally evaporating Au onto the CYTOP modification layer through a shadow mask to prepare a source-drain electrode, and then contacting the photosensitive charge transport layer of the blended film with the source-drain electrode to prepare the organic artificial photoelectric synapse device.
5. The preparation method according to claim 4, characterized in that: The thickness of the SiO2 layer in the Si / SiO2 substrate is 300nm.
6. The preparation method according to claim 4, characterized in that: The channel length and width of the source-drain electrodes are 100 μm and 1000 μm, respectively.
7. The preparation method according to claim 4, characterized in that: The spin coating parameters of the modified layer are a speed of 3000 rpm for 40 seconds: and the shadow mask thermal evaporation thickness of the source-drain electrode is 50 nm.
8. The preparation method according to claim 4, characterized in that: The preparation steps of the blended film are as follows: spin coating a mixed solution of P3HT-b-PPI (5F) and PMMA onto a Si / PVA substrate, and then peeling off the mixed solution after drying to obtain a vertically phase-separated blended film.
9. The preparation method according to claim 8, characterized in that: The solvent of the P3HT-b-PPI (5F) and PMMA mixed solution is dichlorobenzene, wherein the concentration of P3HT-b-PPI (5F) in the mixed solution is 1 mg / mL, and the concentration of PMMA in the mixed solution is 3 wt %; the specific parameters of the spin coating are a speed of 2000 rpm and a duration of 60 seconds.
10. The preparation method according to claim 8, characterized in that: The Si / PVA substrate is prepared by spin coating a 2 wt % PVA aqueous solution on a Si substrate, wherein the specific parameters of the spin coating are a speed of 4500 rpm and a duration of 40 seconds.