Organic synaptic device with high polarization sensitivity and preparation method thereof

Abstract

The invention discloses an organic synaptic device with high polarization sensitivity and a preparation method of the organic synaptic device, and belongs to the technical field of photoelectric materials and neuromorphic computation.The organic synaptic device comprises a first solid-phase substrate, a capture layer and an active layer from bottom to top, the active layer comprises a first two-dimensional organic molecule crystal film and a second two-dimensional organic molecule crystal film which are in contact with the capture layer, the second two-dimensional organic molecule crystal film is partially stacked on the first two-dimensional organic molecule crystal film to form an II-type energy band heterojunction, and a first electrode is arranged on the surface of the first two-dimensional organic molecule crystal film; and a second electrode is arranged on the second two-dimensional organic molecular crystal film. The device successfully breaks through the intrinsic anisotropy limitation of a two-dimensional semiconductor material, the noise of the device is remarkably reduced, and the light response intensity and the polarization detection capability are greatly enhanced.

Description

Technical Field

[0001] The present invention relates to an organic synaptic device with high polarization sensitivity and a preparation method thereof, belonging to the technical fields of optoelectronic materials and neuromorphic computing. Background Art

[0002] Polarization vision imaging technology provides a new visual dimension for agents' perception and decision-making in complex environments by analyzing the polarization information of light, significantly enhancing their adaptability in dynamic scenarios. Inspired by the biological visual system, the integrated sensing and computing polarization-sensitive artificial synapses show great application potential in the field of bionic vision. This technology can not only effectively break through the performance bottleneck of the traditional von Neumann architecture but also provide a new solution for high-performance computing, thus promoting the leapfrog development of polarization vision imaging technology.

[0003] Traditional polarization-sensitive devices are mostly based on inorganic materials. However, their inherent limitations (such as high manufacturing costs, poor compatibility with flexible substrates, and complex micro-nano processing techniques) severely restrict their practical application value in flexible electronics and miniaturized intelligent integrated devices. Two-dimensional organic molecular crystals, due to their unique intrinsic anisotropy and excellent optoelectronic response characteristics, combined with the mechanism of photoinduced trapping of minority carriers, have become ideal candidate materials for a new generation of miniaturized, on-chip integrated linear polarization light-responsive artificial intelligence sensing systems, opening up broad prospects for the development of future intelligent sensing technologies.

[0004] However, although two-dimensional organic molecular crystals show significant advantages in synaptic linear polarization light recognition, their intrinsic anisotropy still limits the further improvement of the dichroic ratio and is difficult to meet the requirements of high sensitivity in practical applications. Therefore, exploring new strategies to break through the limitations of material intrinsic anisotropy and further improve the linear polarization sensitivity of optoelectronic synaptic devices has become the current research focus. Summary of the Invention

[0005] To overcome the deficiencies of the prior art, the present invention provides an organic synaptic device with high polarization sensitivity and a preparation method thereof, which can break through the limitations of the intrinsic anisotropy of two-dimensional semiconductor materials and achieve high polarization sensitivity.

[0006] The technical solution adopted by the present invention to solve its technical problems is as follows: In a first aspect, the present application provides a preparation method for an organic synaptic device with high polarization sensitivity, including the following steps: Prepare a capture layer on a first solid-phase substrate; Prepare a first two-dimensional organic molecular crystal film with an area smaller than that of the capture layer on a first liquid-phase substrate, and prepare a second two-dimensional organic molecular crystal film with an area smaller than that of the capture layer on a second liquid-phase substrate; transferring the first two-dimensional organic molecular crystal film onto the capture layer; Transferring the second two-dimensional organic molecular crystal film to the capture layer so that the first two-dimensional organic molecular crystal film and the second two-dimensional organic molecular crystal film intersect in shape and form a type II energy band heterojunction; Electrodes are prepared on the surfaces of the first two-dimensional organic molecular crystal film and the second two-dimensional organic molecular crystal film respectively to obtain the organic synapse device with high polarization sensitivity.

[0007] The device produced by the method for preparing an organic synaptic device with high polarization sensitivity provided in the present application successfully breaks through the intrinsic anisotropy limitation of two-dimensional semiconductor materials, not only significantly reduces the device noise, but also greatly enhances the light response intensity and polarization detection capability.

[0008] In order to realize the structure that both the first two-dimensional organic molecular crystal film and the second two-dimensional organic molecular crystal film are in contact with the capture layer, and the second two-dimensional organic molecular crystal film is partially overlapped on the first two-dimensional organic molecular crystal film, the area of ​​the first two-dimensional organic molecular crystal film prepared on the first liquid phase substrate in the present application is smaller than the capture layer, which can be brought into contact with the capture layer by simply contacting and lifting, and there is an exposed position on the capture layer ready to contact with the second two-dimensional organic molecular crystal film. If the operation of transferring the second two-dimensional organic molecular crystal film to the capture layer is also a simple contact lifting, the randomness is relatively large, and it is difficult to align with the naked eye at the micro-nano scale (device size), then the second two-dimensional organic molecular crystal film is difficult to adhere to the ideal position, and after the second two-dimensional organic molecular crystal film adheres to the first solid phase substrate, the size or shape of the position where the electrode can be arranged on the surface of the first two-dimensional organic molecular crystal film may also be unsatisfactory.

[0009] Preferably, the step of transferring the second two-dimensional organic molecular crystal film onto the capture layer so that the first two-dimensional organic molecular crystal film and the second two-dimensional organic molecular crystal film intersect in shape and form a type II energy band heterojunction comprises: contacting the second liquid phase substrate with a second solid phase substrate having a UV anti-adhesion film on one side so that the second two-dimensional organic molecular crystal film adheres to the UV anti-adhesion film, and lifting and drying the second solid phase substrate; The first solid substrate is contacted with the second solid substrate so that the first two-dimensional organic molecular crystal film and the second two-dimensional organic molecular crystal film face to face, so that the first two-dimensional organic molecular crystal film and the second two-dimensional organic molecular crystal film intersect in shape and form a type II energy band heterojunction; The UV anti-viscosity film is irradiated with ultraviolet rays to make it lose its viscosity, and the second solid phase substrate is peeled off.

[0010] In this application, first, the second solid-phase substrate with a UV release film is used to contact and lift the second two-dimensional organic molecular crystal film. Thereafter, the relative positions of the first solid-phase substrate and the second solid-phase substrate can be easily adjusted, and the second two-dimensional organic molecular crystal film can be easily arranged at an ideal position on the first solid-phase substrate, fully contacting the capture layer and the first two-dimensional organic molecular crystal film, and ensuring that the size and shape of the position where the first two-dimensional organic molecular crystal film is still exposed are suitable for arranging one of the electrodes (the first electrode hereinafter).

[0011] More preferably, the step of making the first solid-phase substrate contact the second solid-phase substrate with the first two-dimensional organic molecular crystal film facing the second two-dimensional organic molecular crystal film so that the shapes of the first two-dimensional organic molecular crystal film and the second two-dimensional organic molecular crystal film intersect and form a type-II energy band heterojunction includes: Placing the first solid-phase substrate on the platform with the first two-dimensional organic molecular crystal film facing upward; Suspending and fixing the transparent second solid-phase substrate on the cantilever with the second two-dimensional organic molecular crystal film facing downward; Adjusting the cantilever so that the vertical projection of the second two-dimensional organic molecular crystal film is within the range of the capture layer, and the vertical projection of the second two-dimensional organic molecular crystal film intersects the shape of the first two-dimensional organic molecular crystal film; Lowering the cantilever until the first two-dimensional organic molecular crystal film contacts the second two-dimensional organic molecular crystal film.

[0012] The transparent second solid-phase substrate can be, for example, a glass plate, which is beneficial for vertically observing the position of the second two-dimensional organic molecular crystal film relative to the first two-dimensional organic molecular crystal film and relative to the capture layer under the observation of a microscope when the second solid-phase substrate is suspended. After alignment, the second solid-phase substrate is lowered to make the second two-dimensional organic molecular crystal film adhere to the first two-dimensional organic molecular crystal film and the capture layer.

[0013] Optionally, the UV release film is selected from one of Lionion 6360-15, Lionion 6360-20, Lionion 6360-25, and Lionion 6360-95; In the step of irradiating the UV release film with ultraviolet light to make it lose its viscosity, the light wavelength is 365 nm, the light intensity is 1 mW / cm 2 ~50 mW / cm 2 , and the irradiation time is 10 s to 30 s.

[0014] Selecting a specific UV release film and strictly defining the light parameters can ensure that the UV release film plays the best role in the crystal film transfer process. A suitable release film can not only ensure the adhesion effect of the crystal film during transfer, but also make it lose its viscosity smoothly through light irradiation and achieve peeling in the subsequent process, avoiding damage to the second two-dimensional organic molecular crystal film and avoiding damage to the heterojunction, thereby steadily improving the preparation quality of the heterojunction and optimizing the polarization-sensitive performance of the device.

[0015] Preferably, the UV release film is Lionon 6360-15; In the step of irradiating the UV release film with ultraviolet light to make it lose its viscosity, the light intensity is 10 mW / cm 2 , and the irradiation time is 30 s.

[0016] This combination of specific materials and light parameters can achieve the best transfer effect, minimize errors in the preparation process, and contribute to improving the stability of the device.

[0017] Optionally, before the step of respectively preparing electrodes on the surfaces of the first two-dimensional organic molecular crystal film and the second two-dimensional organic molecular crystal film, the following steps are further included: Preparing a third two-dimensional organic molecular crystal film with an area smaller than that of the first two-dimensional organic molecular crystal film on a third liquid-phase substrate; Transferring the third two-dimensional organic molecular crystal film to the first solid-phase substrate so that the third two-dimensional organic molecular crystal film partially overlaps on the second two-dimensional organic molecular crystal film and the remaining part overlaps on the first two-dimensional organic molecular crystal film, so that the third two-dimensional organic molecular crystal film and the second two-dimensional organic molecular crystal film form another type-II band heterojunction; The electrode includes a second electrode in contact with the second two-dimensional organic molecular crystal film, and a first electrode in contact with both the first two-dimensional organic molecular crystal film and the third two-dimensional organic molecular crystal film.

[0018] The active layer of the device thus prepared has three layers. The existence of two parallel heterojunctions can completely deplete the intermediate absorption layer and has a higher polarization sensitivity than the bilayer two-dimensional organic molecular crystal film.

[0019] In a second aspect, the present application provides an organic synaptic device with high polarization sensitivity, which includes a first solid-phase substrate, a capture layer, and an active layer from bottom to top. The active layer includes a first two-dimensional organic molecular crystal film and a second two-dimensional organic molecular crystal film both in contact with the capture layer. The second two-dimensional organic molecular crystal film partially overlaps on the first two-dimensional organic molecular crystal film to form a type-II band heterojunction. A first electrode is provided on the surface of the first two-dimensional organic molecular crystal film, and a second electrode is provided on the second two-dimensional organic molecular crystal film.

[0020] The device is a high-performance and strongly polarization-sensitive optoelectronic synaptic device based on the hetero-integration of two-dimensional organic molecular crystals. Through the collaborative setting of highly crystalline two-dimensional organic molecular crystals and type-II band heterojunctions, it can effectively regulate polarization-dependent charge transport, achieve high polarization sensitivity and optoelectronic synaptic functions. This device is suitable for intelligent polarization imaging, dynamic target tracking, and light-controlled neuromorphic computing systems, solving the problem of insufficient sensitivity caused by the limitation of the intrinsic anisotropy of traditional devices.

[0021] Furthermore, the linear polarization dichroism ratio of the organic synaptic device with high polarization sensitivity is ≥10.

[0022] A high numerical linear polarization dichroism ratio indicates that the device has extremely high sensitivity in polarization light detection and can accurately distinguish light signals with different polarization directions. This breaks through the limitation of the intrinsic anisotropy of the material, significantly improves the performance of polarization vision imaging and light-controlled neuromorphic computing systems, and enables them to be applied to high-end fields with extremely high requirements for polarization light sensitivity.

[0023] Furthermore, the thickness of the first two-dimensional organic molecular crystal film is 1 nm to 100 nm, the thickness of the second two-dimensional organic molecular crystal film is 1 nm to 100 nm, the thickness of the capture layer is 5 nm to 15 nm, the thickness of the first electrode is 10 nm to 100 nm, and the thickness of the second electrode is 10 nm to 100 nm.

[0024] Appropriate film thicknesses can give full play to the characteristics of the materials, optimize the contact quality with the electrodes, and are beneficial to optimizing charge injection and transport. These factors work together to improve the overall performance of the device, ensure the stable realization of high polarization sensitivity, and enhance the reliability of the device during operation.

[0025] Furthermore, the active layer further includes a third two-dimensional organic molecular crystal film. The third two-dimensional organic molecular crystal film partially overlaps on the second two-dimensional organic molecular crystal film, and the remaining part overlaps on the first two-dimensional organic molecular crystal film. The third two-dimensional organic molecular crystal film and the second two-dimensional organic molecular crystal film form another type-II band heterojunction; the first electrode is in contact with both the first two-dimensional organic molecular crystal film and the third two-dimensional organic molecular crystal film.

[0026] The beneficial effects of the present invention are as follows: By adopting a heterojunction structure with a type-II band alignment and combining the high crystallinity of two-dimensional organic molecular crystals, the device prepared by the present invention significantly improves the separation efficiency and transport speed of photo-generated carriers, while effectively suppressing the generation of dark current. In addition, the built-in electric field induced in the heterojunction can precisely regulate the polarization-dependent charge transport in the conductive channel, thereby achieving a significant amplification of anisotropic photocurrent. Finally, the device has made a breakthrough in high polarization sensitivity and excellent optoelectronic response characteristics, providing a reliable technical path for the development of high-performance polarization-sensitive neuromorphic devices.

[0027] Other features and advantages of the present application will be described in the subsequent specification, and some of them will become apparent from the specification or be understood by implementing the present application. The objectives and other advantages of the present application can be achieved and obtained by the structures specifically pointed out in the written specification and the drawings. Brief Description of the Drawings

[0028] Figure 1 It is one of the schematic structural diagrams of an organic synaptic device with high polarization sensitivity provided by an embodiment of the present application.

[0029] Figure 2 It is the second of the schematic structural diagrams of an organic synaptic device with high polarization sensitivity provided by an embodiment of the present application.

[0030] Figure 3 It is the schematic flow diagram of a preparation method of an organic synaptic device with high polarization sensitivity provided by an embodiment of the present application.

[0031] Figure 4 It is the schematic diagram of the type-II band alignment of the DTT-8 / TFT-CN heterojunction.

[0032] Figure 5 It is the optical microscope image of the heterojunction prepared in the implementation case.

[0033] Figure 6 It is the test result of the polarization synaptic performance of the device prepared in the implementation case.

[0034] Reference Numerals: 1, First solid-phase substrate; 2, Capture layer; 3, Active layer; 31, First two-dimensional organic molecular crystal film; 32, Second two-dimensional organic molecular crystal film; 33, Third two-dimensional organic molecular crystal film; 41, First electrode; 42, Second electrode; 5, Second solid-phase substrate. Detailed Embodiments

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present disclosure clearer, the technical solutions of the embodiments of the present disclosure will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present disclosure, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present disclosure without creative efforts fall within the scope of protection of the present invention.

[0036] It should be understood that, on the premise of no conflict, any and all implementation schemes of the present invention can be combined with the technical features in any other implementation scheme or multiple other implementation schemes to obtain additional implementation schemes. The present invention includes such additional implementation schemes obtained by combination.

[0037] Unless otherwise specified, all technical terms and scientific terms used herein have the standard meanings in the field to which the claimed subject belongs. If there are multiple definitions for a certain term, the definition in this article shall prevail.

[0038] Referring to Figure 1 , an organic synaptic device with high polarization sensitivity is provided in an embodiment of the present application. From bottom to top, it includes a first solid-phase substrate 1, a capture layer 2, and an active layer. The active layer includes a first two-dimensional organic molecular crystal film 31 and a second two-dimensional organic molecular crystal film 32 that are both in contact with the capture layer 2. The second two-dimensional organic molecular crystal film 32 partially overlaps the first two-dimensional organic molecular crystal film 31 to form a type-II energy band heterojunction. A first electrode 41 is disposed on the surface of the first two-dimensional organic molecular crystal film, and a second electrode 42 is disposed on the second two-dimensional organic molecular crystal film.

[0039] This device realizes the optoelectronic synaptic function with high polarization sensitivity and zero power consumption by synergistically regulating the polarization-dependent charge transport path through the built-in electric field in the heterojunction and the intrinsic anisotropy of the organic single-crystal material.

[0040] Among them, the material of the electrodes (including the first electrode and the second electrode) can be gold, silver, copper, etc. The electrodes are located at both ends of the heterojunction layer to form a source electrode and a drain electrode.

[0041] The material of the capture layer can be PMMA (polymethyl methacrylate), PS (polystyrene), PVN (poly(2-vinylnaphthalene)), PVA (polyvinyl alcohol), or PVP (poly(4-vinylphenol)).

[0042] The first solid-phase substrate can be a silicon wafer, silicon dioxide, or PET (polyethylene terephthalate), etc.

[0043] The thickness of the first two-dimensional organic molecular crystal film is 1 nm to 100 nm, the thickness of the second two-dimensional organic molecular crystal film is 1 nm to 100 nm, the thickness of the capture layer is 5 nm to 15 nm, the thickness of the first electrode is 10 nm to 100 nm, and the thickness of the second electrode is 10 nm to 100 nm.

[0044] The two-dimensional organic molecules crystal is selected from TFT-CN, DTT-8, C6-DPA, C8-BTBT, C12-BTBT, and TIPS-PEN. When the first two-dimensional organic molecular crystal film selects TFT-CN, the second two-dimensional organic molecular crystal film selects one of DTT-8, C6-DPA, C8-BTBT, C12-BTBT, and TIPS-PEN; when the first two-dimensional organic molecular crystal film selects one of DTT-8, C6-DPA, C8-BTBT, C12-BTBT, and TIPS-PEN, the second two-dimensional organic molecular crystal film selects TFT-CN.

[0045] The type-II energy band alignment of the heterojunction significantly improves the separation efficiency of photo-generated carriers, suppresses the dark current, and drives the anisotropic charge transport directionally through the built-in electric field, enabling the linear polarization dichroism ratio to break through to ≥10.

[0046] In some embodiments, the first two-dimensional organic molecular crystal film is DDT-8, the second two-dimensional organic molecular crystal film is TFT-CN, the first electrode is gold, and the second electrode is silver.

[0047] The present application correspondingly provides a preparation method for the device, and the steps include: S1: Prepare a capture layer on the first solid-phase substrate.

[0048] S2: Prepare a first two-dimensional organic molecular crystal film with an area smaller than that of the capture layer on the first liquid-phase substrate, and prepare a second two-dimensional organic molecular crystal film with an area smaller than that of the capture layer on the second liquid-phase substrate.

[0049] S3: Transfer the first two-dimensional organic molecular crystal film onto the capture layer.

[0050] S4: Transfer the second two-dimensional organic molecular crystal film onto the capture layer so that the first two-dimensional organic molecular crystal film intersects with the second two-dimensional organic molecular crystal film in shape and forms a type-II energy band heterojunction.

[0051] S6: Prepare electrodes on the surfaces of the first two-dimensional organic molecular crystal film and the second two-dimensional organic molecular crystal film respectively to obtain an organic synaptic device with high polarization sensitivity.

[0052] Step S1 can specifically be spin-coating a capture layer thin film on the surface of the first solid-phase substrate using a spin-coating method.

[0053] The specific steps of step S2 are as follows: Drop a first organic semiconductor solution onto a first liquid-phase substrate, and the first organic semiconductor solution spreads into a continuous liquid film on the first liquid-phase substrate; drop a second organic semiconductor solution onto a second liquid-phase substrate, and the second organic semiconductor solution spreads into a continuous liquid film on the second liquid-phase substrate.

[0054] After the volatile organic solvent completely volatilizes, a uniform two-dimensional organic molecular crystal is formed on the surface of the liquid-phase substrate. That is, a first two-dimensional organic molecular crystal film is obtained on the surface of the first liquid-phase substrate, and a second two-dimensional organic molecular crystal film is obtained on the surface of the second liquid-phase substrate.

[0055] Among them, the solute of the first organic semiconductor solution is, for example, one of DTT-8, C6-DPA, C8-BTBT, C12-BTBT, TIPS-PEN, and the solute of the second organic semiconductor solution is, for example, TFT-CN. Conversely, the solute of the second organic semiconductor solution can be one of DTT-8, C6-DPA, C8-BTBT, C12-BTBT, TIPS-PEN, and the solute of the first organic semiconductor solution is, for example, TFT-CN.

[0056] The solvents of the first organic semiconductor solution and the second organic semiconductor solution can independently be toluene, chlorobenzene, or ortho-dichlorobenzene to ensure that the solution can slowly volatilize after dropping to form a uniform single-crystal thin film.

[0057] The first liquid-phase substrate and the second liquid-phase substrate can independently be water, glycerol, or a mixture thereof. By introducing the liquid-phase substrate, the coffee ring effect can be effectively inhibited, thereby obtaining a two-dimensional organic molecular crystal with a uniform and controllable thickness.

[0058] The concentration ranges of the first organic semiconductor solution and the second organic semiconductor solution are independently 0.01 mg / mL to 8 mg / mL, and can be specifically adjusted according to the thickness and morphology requirements of the target thin film.

[0059] The dropping amount of the organic semiconductor solution can be precisely controlled according to actual needs. For example, in a weighing bottle with a specification of 40 mm×70 mm, the dropping amount is usually 10 μL to 100 μL. By adjusting the dropping amount, precise control of the thickness of the two-dimensional organic molecular crystal can be achieved, and the thickness range can be from a single molecular layer to several hundred nanometers. In this application, the thickness of each two-dimensional organic molecular crystal in the heterojunction is 1 nm to 100 nm.

[0060] The specific steps of step S3 are as follows: Align the first solid-phase substrate with the first two-dimensional organic molecular crystal film on the liquid surface of the first liquid-phase substrate, slowly approach it, and use the side with the capture layer to contact the well-grown two-dimensional organic molecular crystal on the liquid surface. After sufficient contact between the two, slowly lift the first solid-phase substrate away from the liquid surface, and the two-dimensional organic molecular crystal prepared on the first liquid-phase substrate will be transferred to the first solid-phase substrate. Then, rinse the first solid-phase substrate with deionized water and air-dry it to obtain the first two-dimensional organic molecular crystal film on the first solid-phase substrate. Similarly, the second two-dimensional organic molecular crystal film can also be picked up by contacting the first solid-phase substrate that has already adhered to the first two-dimensional organic molecular crystal film and attached to the first solid-phase substrate.

[0061] This application also provides an optimized device. Referring to Figure 2 , the active layer further includes a third two-dimensional organic molecular crystal film 33. The third two-dimensional organic molecular crystal film 33 partially overlaps the second two-dimensional organic molecular crystal film 32, and the remaining part overlaps the first two-dimensional organic molecular crystal film 31. And before arranging the electrodes, there is still an exposed part on the first two-dimensional organic molecular crystal film 31. The third two-dimensional organic molecular crystal film 33 and the second two-dimensional organic molecular crystal film 32 form another type-II energy band heterojunction; the first electrode 41 contacts both the first two-dimensional organic molecular crystal film 31 and the third two-dimensional organic molecular crystal film 33.

[0062] In this way, the active layer has three layers and has a higher polarization sensitivity than the double-layer two-dimensional organic molecular crystal film.

[0063] In this device, the thickness of the third two-dimensional organic molecular crystal film 33 is 1 nm to 100 nm, and the thickness requirements of the other layers are the same as those when the active layer has two layers.

[0064] In this device, both the first two-dimensional organic molecular crystal film 31 and the third two-dimensional organic molecular crystal film 33 are TFT-CN, the second two-dimensional organic molecular crystal film 32 is one of DTT-8, C6-DPA, C8-BTBT, C12-BTBT, TIPS-PEN, the first electrode is silver, and the second electrode is gold.

[0065] Although the operation of picking up by contact in the aforementioned step S3 is simple, the adhesion position of the organic molecular crystal film has a large randomness. In order to make the first two-dimensional organic molecular crystal film contact the capture layer and there is still an exposed position on the capture layer for contacting the second two-dimensional organic molecular crystal film, this application stipulates that the area of the first two-dimensional organic molecular crystal film is smaller than that of the capture layer, which can be achieved by adjusting the volume of the first organic semiconductor solution.

[0066] However, when it is necessary to arrange the second two-dimensional organic molecular crystal film according to a preset structure, or even to arrange the third two-dimensional organic molecular crystal film, if the two layers or even three layers are picked up by contact, the randomness is too large. Just controlling the area of the two-dimensional organic molecular crystal film to be smaller than the capture layer still does not easily make the second two-dimensional organic molecular crystal film and the third two-dimensional organic molecular crystal film adhere to the ideal positions on the first solid-phase substrate, especially at the micro-nano device scale.

[0067] The present application proposes a better transfer operation for this purpose. Referring to Figure 3 , taking the active layer 3 containing two two-dimensional organic molecular crystal films as an example.

[0068] First, as shown in Figure 3 the first row, bring the first solid-phase substrate 1 close to the first two-dimensional organic molecular crystal film on the liquid surface of the first liquid-phase substrate, and use the side with a capture layer (to avoid too complex a hierarchy, Figure 3 the capture layer is not drawn in the figure) to contact the two-dimensional organic molecular crystal grown on the liquid surface. After sufficient contact between the two, lift the first solid-phase substrate away from the liquid surface, and the two-dimensional organic molecular crystal prepared on the first liquid-phase substrate will be transferred to the first solid-phase substrate. Then, rinse the first solid-phase substrate with deionized water and air-dry it to obtain the first two-dimensional organic molecular crystal film 31 on the first solid-phase substrate.

[0069] Then, as shown in Figure 3 the second row, slowly bring the second solid-phase substrate 5 with a UV release film (to avoid too complex a hierarchy, Figure 3 the UV release film is not drawn in the figure) close to and contact the second two-dimensional organic molecular crystal film grown on the liquid surface. After sufficient contact between the two, slowly lift the second solid-phase substrate away from the liquid surface, and the second two-dimensional organic molecular crystal film 32 will adhere to the UV release film, and then rinse and dry it.

[0070] Again, as shown in Figure 3In the third step, flip the entire second solid-phase substrate and suspend it and fix it on the adjustable cantilever of the two-dimensional material transfer platform, and perform vertical crystal alignment under an optical microscope. "Alignment" specifically means that, for example, in the vertical projection, at least 20% of the area of the second two-dimensional organic molecular crystal film intersects with the first two-dimensional organic molecular crystal film, at least 20% of the area of the second two-dimensional organic molecular crystal film intersects with the capture layer, and at least 30% of the area of the first two-dimensional organic molecular crystal film is not covered. After alignment, lower the height of the cantilever so that the UV release film (alignment is observed through a microscope, and during the lowering process, it can be directly observed with the naked eye from the side while combining microscope observation. When observing with the naked eye, the UV release film is easier to identify than the second two-dimensional organic molecular crystal film) is in full contact with the first solid-phase substrate covered with the first two-dimensional organic molecular crystal film below (similarly, when observing with the naked eye, the first solid-phase substrate is easier to identify than the first two-dimensional organic molecular crystal film and the capture layer). Subsequently, irradiate the UV release film with appropriate UV light to make the UV release film lose its adhesiveness. After slowly lifting the second solid-phase substrate, the second two-dimensional organic molecular crystal film can be peeled off from the glass carrier (the second solid-phase substrate), and finally, the preparation of a heterojunction with vertically aligned crystals can be achieved.

[0071] In this way, it is easy to make the second two-dimensional organic molecular crystal film be in full contact with the capture layer, make the second two-dimensional organic molecular crystal film be in full contact with the first two-dimensional organic molecular crystal film, and ensure that the size and shape of the position where the first two-dimensional organic molecular crystal film is still exposed are suitable for arranging electrodes. It not only ensures that the preset device structure can be assembled, but also ensures that the interlayer interface has atomic-level flatness.

[0072] Specifically, the UV release film is selected from one of Lion 6360-15, Lion 6360-20, Lion 6360-25, and Lion 6360-95; in the step of irradiating the UV release film with ultraviolet light to make it lose its adhesiveness, the light wavelength is 365 nm, and the light intensity is 1 mW / cm 2 ~50 mW / cm 2 , and the irradiation time is 10 s to 30 s. Most preferably, the UV release film is Lion 6360-15; in the step of irradiating the UV release film with ultraviolet light to make it lose its adhesiveness, the light intensity is 10 mW / cm 2 , and the irradiation time is 30 s. It should be noted that the connection method between the UV release film and the second solid-phase substrate does not rely on the adhesiveness of the UV release film itself, but uses another connection method. For example, fix the corners of the UV release film on a transparent glass plate with tape, or use another adhesive to stick the UV release film firmly on the second solid-phase substrate in advance. In this way, when the second solid-phase substrate is lifted after UV irradiation, the UV release film will not fall on the first solid-phase substrate.

[0073] Due to the large randomness of contact lifting, it is more difficult when the active layer is composed of three stacked layers. Similarly, the third two-dimensional organic molecular crystal film can also achieve the transfer and hetero-stacking of two-dimensional organic molecules with the help of a UV release film and a two-dimensional material transfer platform.

[0074] That is, a third solid substrate with a UV release film on one side is contacted with a third liquid substrate so that the third two-dimensional organic molecular crystal film adheres to the UV release film, and the third solid substrate is lifted and dried; The first solid substrate and the third solid substrate are contacted with the second two-dimensional organic molecular crystal film and the third two-dimensional organic molecular crystal film facing each other, so that the third two-dimensional organic molecular crystal film partially overlaps the second two-dimensional organic molecular crystal film, and the remaining part overlaps the first two-dimensional organic molecular crystal film, and there is still an exposed part on the first two-dimensional organic molecular crystal film. The third two-dimensional organic molecular crystal film and the second two-dimensional organic molecular crystal film form another type-II energy band heterojunction; The UV release film is irradiated with ultraviolet light to make it lose its viscosity, and the third solid substrate is peeled off.

[0075] When aligning the third two-dimensional organic molecular crystal film, for example, at least 15% of the area of the third two-dimensional organic molecular crystal film can intersect with the second two-dimensional organic molecular crystal film, and at least 10% of the area of the first two-dimensional organic molecular crystal film is not covered.

[0076] Implementation case First, prepare a PMMA (polymethyl methacrylate) chlorobenzene solution with a concentration of 3 mg / mL, and spin-coat it evenly on the surface of the SiO2 / Si substrate. Subsequently, it is annealed at 120 °C for 10 minutes to form a PMMA capture layer with a thickness of about 10 nm. This capture layer effectively regulates the charge capture and release kinetic processes and plays an important role in simulating synaptic plasticity behavior.

[0077] Next, prepare a DTT-8 chlorobenzene solution with a concentration of 0.8 mg / mL and a TFT-CN chlorobenzene solution with a concentration of 0.1 mg / mL respectively. These two solutions are respectively dropped on the surface of the glycerol substrate. After the chlorobenzene solvent completely evaporates, a DTT-8 two-dimensional organic molecular crystal thin film with a thickness of about 14 nm and a TFT-CN two-dimensional organic molecular crystal thin film with a thickness of about 10 nm are respectively formed on the glycerol substrate. The use of the glycerol substrate effectively inhibits the coffee ring effect and ensures the uniformity and high quality of the thin film.

[0078] Subsequently, the DTT-8 two-dimensional organic molecular crystal thin film prepared on the glycerol substrate is transferred to the SiO2 / Si substrate covered with the PMMA capture layer by contact lifting. Then, using a UV release film, the TFT-CN two-dimensional organic molecular crystal thin film is transferred to the surface of the DTT-8 thin film, and a type-II energy band heterojunction structure is successfully constructed.

[0079] At this time, observed under an optical microscope, as Figure 5 ("substrate" in Figure 5 refers to the first solid-phase substrate on the surface of which a PMMA capture layer is formed) shows that the surface of the thin film is smooth, the edges are clearly distinguishable, and the morphology is regular and uniform, indicating a high assembly quality of the two-dimensional organic molecular crystal heterojunction.

[0080] With the assistance of an optical microscope, using the probe mechanical transfer technique, an Au electrode is prepared on the surface of the DTT-8 thin film, and an Ag electrode is prepared on the surface of the TFT-CN thin film, and finally a complete synaptic device is constructed. This device consists of an Ag / Au electrode, a DTT-8 / TFT-CN two-dimensional organic molecular crystal heterojunction, a PMMA capture layer, and a SiO2 / Si substrate from top to bottom.

[0081] Referring to Figure 4 , the curve HOMO represents the top of the valence band; the curve LUMO represents the bottom of the conduction band; the circled e represents an electron, and the upward arrow indicates that near the contact interface of the two materials, electrons move from the LUMO of DTT-8 to the LUMO of TFT-CN; the circled h represents a hole, and the downward arrow indicates that near the contact interface of the two materials, holes move from the HOMO of TFT-CN to the HOMO of DTT-8. The type-II energy band alignment of the heterojunction formed by DTT-8 and TFT-CN demonstrates its efficient carrier separation mechanism.

[0082] The polarization-sensitive performance of this device was tested, and the results are as Figure 6 shown. Under the irradiation of 365 nm polarized light (polarization angles of 0° and 90°), the fabricated synaptic device exhibits significant polarization-sensitive synaptic behavior. The dichroic ratio (δ value) of its postsynaptic current is as high as 10.0, far exceeding the theoretical δ value (3.41) of the pure DTT-8 two-dimensional organic molecular crystal. This result indicates that through the collaborative design of heterojunction energy band engineering and the anisotropy of organic single crystal materials, combined with the mechanism of the capture layer capturing minority carriers, the sensitivity limitation of traditional polarization synaptic devices has been successfully broken through, providing a high-performance hardware foundation for intelligent polarization sensing and opto-controlled neural computing.

[0083] This application belongs to the cross - technical field of optoelectronic materials and neuromorphic computing. Through a clever heterojunction design, the efficient polarization detection advantage of the "intrinsic linear dichroism" of two - dimensional organic molecular crystals is combined with the efficient driving characteristics of the built - in electric field in the heterojunction, realizing the collaborative optimization of material properties. This design not only effectively breaks through the limitations of the intrinsic anisotropy of the material, but also enables the device to make breakthrough progress in high polarization sensitivity and superior optoelectronic response characteristics. It is applicable to bionic visual perception, polarization imaging, and light - controlled neuromorphic systems, providing strong technical support for the development of future intelligent sensing technologies and facilitating the leap - forward development of polarization vision imaging technology.

[0084] In the description of this specification, the description with reference to terms such as "one embodiment", "certain embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above - mentioned terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0085] The above - mentioned are the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art in this technical field, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements are also regarded as the protection scope of the present invention.

Claims

1. A method for preparing an organic synaptic device with high polarization sensitivity, characterized in that, Including the following steps: Preparing a capture layer on a first solid-phase substrate; Preparing a first two-dimensional organic molecular crystal film with an area smaller than that of the capture layer on a first liquid-phase substrate, and preparing a second two-dimensional organic molecular crystal film with an area smaller than that of the capture layer on a second liquid-phase substrate; Transferring the first two-dimensional organic molecular crystal film onto the capture layer; Transferring the second two-dimensional organic molecular crystal film onto the capture layer so that the first two-dimensional organic molecular crystal film and the second two-dimensional organic molecular crystal film intersect in shape and form a type-II energy band heterojunction; Preparing electrodes on the surfaces of the first two-dimensional organic molecular crystal film and the second two-dimensional organic molecular crystal film respectively to obtain the organic synaptic device with high polarization sensitivity.

2. The method for preparing an organic synaptic device with high polarization sensitivity according to claim 1, characterized in that, The step of transferring the second two-dimensional organic molecular crystal film onto the capture layer so that the first two-dimensional organic molecular crystal film and the second two-dimensional organic molecular crystal film intersect in shape and form a type-II energy band heterojunction includes: Contacting the second liquid-phase substrate with a second solid-phase substrate having a UV release film on one side to make the second two-dimensional organic molecular crystal film adhere to the UV release film, lifting and drying the second solid-phase substrate; Bringing the first solid-phase substrate into contact with the second solid-phase substrate with the first two-dimensional organic molecular crystal film and the second two-dimensional organic molecular crystal film facing each other so that the first two-dimensional organic molecular crystal film and the second two-dimensional organic molecular crystal film intersect in shape and form a type-II energy band heterojunction; Irradiating the UV release film with ultraviolet light to make it lose its adhesiveness and peeling off the second solid-phase substrate.

3. The method for preparing an organic synaptic device with high polarization sensitivity according to claim 2, wherein The step of bringing the first solid-phase substrate into contact with the second solid-phase substrate with the first two-dimensional organic molecular crystal film and the second two-dimensional organic molecular crystal film facing each other so that the first two-dimensional organic molecular crystal film and the second two-dimensional organic molecular crystal film intersect in shape and form a type-II energy band heterojunction includes: Placing the first solid-phase substrate on a platform with the first two-dimensional organic molecular crystal film facing upward; Suspending and fixing the transparent second solid-phase substrate on a cantilever with the second two-dimensional organic molecular crystal film facing downward; Adjusting the cantilever so that the vertical projection of the second two-dimensional organic molecular crystal film is within the range of the capture layer and the vertical projection of the second two-dimensional organic molecular crystal film intersects in shape with the first two-dimensional organic molecular crystal film; Lowering the cantilever until the first two-dimensional organic molecular crystal film contacts the second two-dimensional organic molecular crystal film.

4. The method for preparing an organic synaptic device with high polarization sensitivity according to claim 2, wherein The UV release film is selected from one of Lionon 6360-15, Lionon 6360-20, Lionon 6360-25, and Lionon 6360-95; In the step of irradiating the UV release film with ultraviolet light to make it lose its adhesiveness, the light wavelength is 365 nm, and the light intensity is 1 mW / cm 2 ~50 mW / cm 2 , and the irradiation time is 10 s to 30 s.

5. The method for preparing an organic synaptic device with high polarization sensitivity according to claim 4, wherein The UV release film is Lionon 6360-15; In the step of irradiating the UV release film with ultraviolet light to make it lose its adhesiveness, the light intensity is 10 mW / cm 2 , and the irradiation time is 30 s.

6. The method for preparing an organic synaptic device with high polarization sensitivity according to claim 1, wherein, Before the step of preparing electrodes on the surfaces of the first two-dimensional organic molecular crystal film and the second two-dimensional organic molecular crystal film respectively, there is also a step of: Preparing a third two-dimensional organic molecular crystal film with an area smaller than that of the first two-dimensional organic molecular crystal film on a third liquid-phase substrate; Transfer the third two-dimensional organic molecular crystal film to the first solid-phase substrate so that a part of the third two-dimensional organic molecular crystal film is stacked on the second two-dimensional organic molecular crystal film and the remaining part is stacked on the first two-dimensional organic molecular crystal film, such that the third two-dimensional organic molecular crystal film and the second two-dimensional organic molecular crystal film form another type-II energy band heterojunction; The electrode includes a second electrode in contact with the second two-dimensional organic molecular crystal film, and a first electrode in contact with both the first two-dimensional organic molecular crystal film and the third two-dimensional organic molecular crystal film.

7. An organic synaptic device with high polarization sensitivity, characterized in that, Prepared by the method for preparing an organic synaptic device with high polarization sensitivity according to any one of claims 1 to 6, comprising, from bottom to top, a first solid-phase substrate, a capture layer, and an active layer. The active layer includes a first two-dimensional organic molecular crystal film and a second two-dimensional organic molecular crystal film both in contact with the capture layer. The second two-dimensional organic molecular crystal film is partially stacked on the first two-dimensional organic molecular crystal film to form a type-II energy band heterojunction. A first electrode is disposed on the surface of the first two-dimensional organic molecular crystal film, and a second electrode is disposed on the second two-dimensional organic molecular crystal film.

8. The organic synaptic device with high polarization sensitivity according to claim 7, characterized in that, The linear polarization dichroism ratio ≥ 10.

9. The organic synaptic device with high polarization sensitivity according to claim 7, wherein The thickness of the first two-dimensional organic molecular crystal film is 1 nm to 100 nm, the thickness of the second two-dimensional organic molecular crystal film is 1 nm to 100 nm, the thickness of the capture layer is 5 nm to 15 nm, the thickness of the first electrode is 10 nm to 100 nm, and the thickness of the second electrode is 10 nm to 100 nm.

10. The organic synaptic device with high polarization sensitivity according to claim 7, characterized in that, The active layer further includes a third two-dimensional organic molecular crystal film. The third two-dimensional organic molecular crystal film is partially stacked on the second two-dimensional organic molecular crystal film and the remaining part is stacked on the first two-dimensional organic molecular crystal film. The third two-dimensional organic molecular crystal film and the second two-dimensional organic molecular crystal film form another type-II energy band heterojunction; the first electrode is in contact with both the first two-dimensional organic molecular crystal film and the third two-dimensional organic molecular crystal film.

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