Thin film, memristor based on black phosphorus-graphene oxide quantum dots and preparation method thereof

Abstract

The present invention provides a thin film, a memristor and a preparation method based on black phosphorus-graphene oxide quantum dots. The thin film includes an upper layer structure, a middle layer structure and a lower layer structure connected together in sequence. The materials of the upper layer structure and the lower layer structure are both graphene oxide nanosheets, and the material of the middle layer structure is a black phosphorus-graphene oxide quantum dot composite. The graphene oxide nanosheets of the upper layer structure and the lower layer structure can well coat the middle layer, and P-C bonds are formed between the graphene oxide nanosheets and the black phosphorus nanosheets on the upper and lower surfaces of the middle layer structure. The preparation of this thin film is simple, and the memristor prepared with this thin film can still maintain good performance after being placed in the natural environment for 3 months.

Description

Technical Field

[0001] The present invention belongs to the technical field of memristor preparation. Specifically, it relates to a thin film, a memristor and a preparation method based on black phosphorus-graphene oxide quantum dots. Background Art

[0002] Currently, the development of computers built with the von Neumann architecture has encountered bottlenecks. The emergence of memristors is expected to solve this problem. As a new type of device, memristors have high-resistance states and low-resistance states similar to those of traditional memories. They can not only store information but also play an important role in the simulation of neural synapses. Memristors can simulate many functions of synapses, such as short-term memory (STM), long-term memory (LTM), paired-pulse facilitation (PPF), spike-timing-dependent plasticity (STDP), etc.

[0003] One of the commonly used materials for preparing memristors is black phosphorus. As a new type of two-dimensional material, black phosphorus has a unique structure, and it has characteristics such as a thickness-dependent direct bandgap adjustable range of 0.5 - 1.8 eV, a wide light absorption range, and high carrier mobility, and has been widely studied in the field of optoelectronic devices. However, due to the poor stability of black phosphorus in air, it is prone to oxidation and will decompose in a water-containing environment, resulting in poor stability of memristors based on black phosphorus, thus limiting the application of black phosphorus in this regard. Moreover, although the high electron mobility of black phosphorus is one of its major advantages, it also means that it is difficult for black phosphorus to store electrons, which also limits its application in the field of memories.

[0004] In addition, many of the devices currently prepared from black phosphorus are based on the mechanical transfer method. For example, Taimur Ahmed et al. reported a horizontally structured black phosphorus photonic memristor prepared by the mechanical transfer method in Small, 2019, 15(22): 1900966. He Tian et al. reported a black phosphorus three-terminal structured synaptic device prepared by the mechanical transfer method in Advanced Materials, 2016, 28(25): 4991 - 4997. Peng Lia et al. reported a black phosphorus multifunctional ion array detector prepared by the mechanical transfer method in Sensors and Actuators B: Chemical, 2018, 273: 358 - 364. The mechanical transfer method is complex in process and low in preparation efficiency, and it is difficult to prepare on a large scale and rapidly. Summary of the Invention

[0005] Based on the above technical problems existing in the prior art, the present invention provides a thin film, a memristor and a preparation method based on black phosphorus-graphene oxide quantum dots, which solve the instability problem of memristors based on black phosphorus materials, and at the same time can simply and conveniently prepare two-dimensional material functional thin films and their memristors on a large area.

[0006] The present invention is achieved through the following technical solutions:

[0007] A thin film based on black phosphorus-graphene oxide quantum dots, comprising an upper structure, a middle structure, and a lower structure connected together in sequence. The materials of the upper structure and the lower structure are both graphene oxide nanosheets, and the material of the middle structure is a black phosphorus-graphene oxide quantum dot composite.

[0008] Preferably, the thicknesses of the upper structure, the middle structure, and the lower structure are 100-250 nanometers respectively.

[0009] Preferably, in the black phosphorus-graphene oxide quantum dot composite, the mass ratio of black phosphorus to graphene oxide quantum dots is 1:1.

[0010] The preparation method of the thin film based on black phosphorus-graphene oxide quantum dots includes:

[0011] (1) Mix the black phosphorus nanosheet solution and the graphene oxide quantum dot solution evenly to obtain a black phosphorus-graphene oxide quantum dot mixed solution;

[0012] (2) Use a vacuum filtration device and a filter membrane to sequentially filter the graphene oxide nanosheet solution, the black phosphorus-graphene oxide quantum dot mixed solution, and the graphene oxide nanosheet solution. After the filtration is completed, vacuum-dry the filter membrane to obtain a thin film based on black phosphorus-graphene oxide quantum dots loaded on the filter membrane.

[0013] Preferably, in step (1), the size of the black phosphorus nanosheets in the black phosphorus nanosheet solution is 200 nanometers to 2 micrometers, and the diameter size of the graphene oxide quantum dots in the graphene oxide quantum dot solution is 5-10 nm; in step (2), the size of the graphene oxide nanosheets in the graphene oxide nanosheet solution is 200 nanometers to 2 micrometers.

[0014] Preferably, in step (1), the preparation of the graphene oxide quantum dot solution: Add a hydrogen peroxide solution to the graphene oxide nanosheet solution to form a mixed solution, and then carry out a photo-Fenton reaction under ultraviolet light irradiation with a wavelength of 365 nanometers. After the reaction is completed, dialysis is carried out to obtain the graphene oxide quantum dot solution.

[0015] A memristor based on black phosphorus-graphene oxide quantum dots includes the thin film based on black phosphorus-graphene oxide quantum dots.

[0016] The preparation method of the memristor based on black phosphorus-graphene oxide quantum dots includes:

[0017] (1) Mix the black phosphorus nanosheet solution and the graphene oxide quantum dot solution evenly to obtain a black phosphorus-graphene oxide quantum dot mixed solution;

[0018] (2) Use a vacuum filtration device and a filter membrane to sequentially filter graphene oxide nanosheet solution, black phosphorus-graphene oxide quantum dot mixed solution, and graphene oxide nanosheet solution. After filtration, vacuum-dry the filter membrane to obtain a black phosphorus-graphene oxide quantum dot-based film with the filter membrane.

[0019] (3) Wet the black phosphorus-graphene oxide quantum dot-based film with the filter membrane using isopropanol, then transfer it to a conductive substrate, apply pressure to closely contact the surface of the black phosphorus-graphene oxide quantum dot-based film with the surface of the conductive substrate. After the transfer is completed, drop acetone onto the filter membrane to dissolve the filter membrane. After the filter membrane is completely dissolved, vacuum-dry it to obtain a black phosphorus-graphene oxide quantum dot-based film transferred to the conductive substrate.

[0020] (4) Assemble the black phosphorus-graphene oxide quantum dot-based film transferred to the conductive substrate with a second electrode to prepare a memristor.

[0021] Preferably, in step (3), the conductive substrate is ITO conductive glass or flexible PETITO.

[0022] Preferably, in step (4), the second electrode is a silver electrode or ITO conductive glass.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The black phosphorus-graphene oxide quantum dot-based film of the present invention includes an upper layer structure, a middle layer structure, and a lower layer structure connected together in sequence. The materials of the upper layer structure and the lower layer structure are both graphene oxide nanosheets, and the material of the middle layer structure is a black phosphorus-graphene oxide quantum dot composite. The graphene oxide nanosheets of the upper layer structure and the lower layer structure can well coat the middle layer. These graphene oxide nanosheets form P-C bonds with the black phosphorus nanosheets on the upper and lower surfaces of the middle layer structure, protecting the middle layer structure from the influence of oxygen and water, ensuring the stability of the middle layer structure, and these P-C bonds can also play a good auxiliary role in the process of electron transport, enabling electrons in black phosphorus to easily transfer to the upper or lower layer structure. The graphene oxide quantum dots in the middle layer structure can adjust the energy band of the middle layer structure under the action of the quantum confinement effect, forming many discrete potential barriers. These potential barriers can well block the movement of electrons, can well reduce the power consumption of the device, and the graphene oxide quantum dots themselves can also absorb electrons and play a role in storing electrons.

[0025] The memristor of the present invention based on a two - electrode vertical structure of black phosphorus - graphene oxide quantum dots. The graphene oxide nanosheets of the upper layer structure and the lower layer structure can well encapsulate the middle layer. The black phosphorus nanosheets on the upper and lower surfaces of the middle layer structure of these graphene oxide nanosheets form P - C bonds, and the device can still maintain good performance after being placed in the natural environment for 3 months. Due to the quantum confinement effect of graphene oxide quantum dots, the energy band of the middle layer structure is adjusted to form many discrete potential barriers, which can well block the movement of electrons, making the device have low power consumption. The memristor of black phosphorus - graphene oxide quantum dots of the present invention can well simulate the basic behaviors of nerve synapses, such as short - term memory (STM), long - term memory (LTM), paired - pulse facilitation (PPF), spike - timing - dependent plasticity (STDP), etc., and can also simulate the function of dendritic nerves, the logical behaviors between multiple neuron synapses, successfully simulate the logical "AND" and logical "OR" functions, and can also simulate the function of biological learning and training, and successfully simulate the "Pavlov" conditioned reflex.

[0026] The present invention transfers the thin film based on black phosphorus - graphene oxide quantum dots to the conductive substrate by dissolving the filter membrane. The process is simple and large - scale preparation can be achieved. Brief Description of the Drawings

[0027] Figure 1 It is the digital photo of the graphene oxide / black phosphorus - graphene oxide quantum dot / graphene oxide memristor prepared in Example 2 of the present invention.

[0028] Figure 2 It is the cross - sectional scanning electron microscope image of the memristor of black phosphorus - graphene oxide quantum dots prepared in Example 2 of the present invention.

[0029] Figure 3 It is the schematic structural diagram of the memristor of black phosphorus - graphene oxide quantum dots of the present invention.

[0030] Figure 4 It is the connection schematic diagram of two memristors of black phosphorus - graphene oxide quantum dots prepared in Example 2 of the present invention.

[0031] Figure 5 It is the paired - pulse facilitation (PPF) data graph of the memristor of black phosphorus - graphene oxide quantum dots in Example 2 of the present invention.

[0032] Figure 6 It is the long - term memory (LTM) data graph of the memristor of black phosphorus - graphene oxide quantum dots in Example 2 of the present invention.

[0033] Figure 7 It is the spike - timing - dependent plasticity (STDP) data graph of the memristor of black phosphorus - graphene oxide quantum dots in Example 2 of the present invention.

[0034] Figure 8 This is the logic "AND" data graph after the connection of two black phosphorus-graphene oxide quantum dot memristors in Embodiment 2 of the present invention.

[0035] Figure 9 This is the logic "OR" data graph after the connection of two black phosphorus-graphene oxide quantum dot memristors in Embodiment 2 and Embodiment 1 of the present invention.

[0036] Figure 10 This is the "Pavlovian" learning data graph after the connection of two black phosphorus-graphene oxide quantum dot memristors in Embodiment 2 of the present invention

[0037] Figure 11 This is the double-pulse facilitation (PPF) data graph of the black phosphorus-graphene oxide quantum dot memristor after being placed for 3 months in Embodiment 2 of the present invention.

[0038] Figure 12 This is the long-term memory (LTM) data graph of the black phosphorus-graphene oxide quantum dot memristor after being placed for 3 months in Embodiment 2 of the present invention. Detailed implementation manners

[0039] To further understand the present invention, the present invention will be described below in conjunction with embodiments. These descriptions are only to further explain the features and advantages of the present invention and are not used to limit the claims of the present invention.

[0040] The thin film based on black phosphorus-graphene oxide quantum dots of the present invention includes an upper layer structure, a middle layer structure and a lower layer structure. The materials of the upper layer structure and the lower layer structure are both graphene oxide nanosheets (GO), and the material of the middle layer structure is a black phosphorus-graphene oxide quantum dot composite (BP-GOQD). The ratio of black phosphorus to graphene oxide quantum dots is 1:1.

[0041] This thin film is denoted as graphene oxide / black phosphorus-graphene oxide quantum dot / graphene oxide thin film.

[0042] The structural schematic diagram of the prepared memristor based on black phosphorus-graphene oxide quantum dots is as Figure 3 shown, and its main structure includes an ITO electrode, a graphene oxide / black phosphorus-graphene oxide quantum dot / graphene oxide thin film, and a silver electrode.

[0043] The preparation process of the graphene oxide / black phosphorus-graphene oxide quantum dot / graphene oxide thin film is as follows:

[0044] (1) Preparation of black phosphorus nanosheet solution: Take 100 - 500 mg of single-crystal black phosphorus bulk material, grind it in a mortar for 10 - 30 minutes in a glove box, then put it into a vacuum ball-milling tank together with stainless steel balls. After connecting to an air pump to evacuate the air, ball-mill it for 4 - 24 hours with a ball-to-material ratio of 100 - 1000:1 and a ball-milling speed of 200 - 400 revolutions per minute. Take out the ball-milled black phosphorus in the glove box and ultrasonically disperse it in an isopropyl alcohol solution. The conditions for ultrasonic dispersion are: the solution temperature is 4 °C, the ultrasonic power is 500 - 1000 W, the ultrasonic time is 6 - 12 hours, and the ultrasonic environment is a dark room. Then centrifuge it with a high-speed centrifuge at a speed of 10000 - 12000 revolutions per minute. After centrifugation, take the supernatant of the solution to obtain a monolayer black phosphorus nanosheet solution with a uniform size distribution and a size ranging from 200 nm to 2 μm;

[0045] (2) Preparation of graphene oxide nanosheet solution: Weigh 100 - 500 mg of the purchased monolayer graphene oxide nanosheets, add 100 - 500 mL of deionized water, and prepare a graphene oxide dispersion by ultrasonic dispersion. The conditions for ultrasonic dispersion are: the solution temperature is 4 °C, the ultrasonic power is 500 - 1000 W, the ultrasonic time is 2 - 6 hours, and the ultrasonic environment is a dark room. Then centrifuge it with a high-speed centrifuge at a speed of 3000 - 12000 revolutions per minute. After centrifugation, take the supernatant of the solution to obtain a monolayer graphene oxide nanosheet solution with a size ranging from 200 nm to 2 μm;

[0046] (3) Preparation of graphene oxide quantum dot solution: Add 0.5 - 2 mL of hydrogen peroxide (30%) solution to a certain amount of the solution obtained in step (2) to make a mixed solution, and then carry out a photo-Fenton reaction under ultraviolet light irradiation with a wavelength of 365 nm (power of 5 - 20 W). The reaction preparation parameters are: the magnetic stirring speed is 50 - 200 revolutions, the stirring time is 40 - 60 minutes. After completion, put it into a dialysis bag with a molecular weight cut-off of 3500 Da and dialyze for 2 - 3 days to obtain a monolayer graphene oxide quantum dot solution with a diameter size of 5 - 10 nm;

[0047] (4) Preparation of black phosphorus-graphene oxide quantum dot mixed solution: Mix the solutions obtained in steps (1) and (3) in a beaker at a ratio of 1:1, and use magnetic stirring to stir at a speed of 20 - 100 revolutions per minute for 5 - 10 minutes to make them fully mixed;

[0048] (5) Preparation of graphene oxide / black phosphorus-graphene oxide quantum dots / graphene oxide hierarchical functional film: Using a vacuum filtration device and a water-based filter membrane with a pore size of 22 microns, sequentially filter 5-10 ml of the solutions obtained in steps (2), (4), and (2). The filtration pressure is 0.85-0.95 Mpa. After completion, take out the filter membrane and place it in a vacuum drying oven for drying. The vacuum degree is 0.08 Mpa, and the drying temperature is 60 °C. By controlling the amount of each solution, a film with upper, middle, and lower layer thicknesses of 100-250 nm can be obtained, and the overall thickness of the film is 300-750 nm.

[0049] A preparation method of a memristor based on black phosphorus-graphene oxide quantum dots, comprising:

[0050] 1) Transfer of graphene oxide / black phosphorus-graphene oxide quantum dots / graphene oxide functional film: Cut a 2*2 cm-sized graphene oxide / black phosphorus-graphene oxide quantum dots / graphene oxide film with a filter membrane prepared in step (5). After wetting with isopropanol, transfer it to the surface of a 2*2 cm-sized ITO conductive glass that has been cleaned by oxygen plasma. Apply a certain pressure to closely contact the surface of the graphene oxide / black phosphorus-graphene oxide quantum dots / graphene oxide film with the ITO surface. After the transfer is completed, drop acetone onto the filter membrane to dissolve the filter membrane. The dropping speed of acetone is 1-4 drops / second, and the angle between the graphene oxide / black phosphorus-graphene oxide quantum dots / graphene oxide film and the horizontal plane is 10-30 degrees. This can make acetone flow smoothly and prevent acetone from aggregating. After the filter membrane is completely dissolved, the graphene oxide / black phosphorus-graphene oxide quantum dots / graphene oxide film transferred to the ITO substrate can be obtained. Then, place the film in a vacuum drying oven for drying, and the vacuum degree is 0.08 Mpa. The sheet resistance of ITO < 7 Ohm / sq. The surface cleaning process used for ITO cleaning is as follows: 1. Use a cleaning agent to clean and remove the oil stain on the ITO surface. After cleaning, rinse it with tap water; 2. Place the ITO cleaned in the previous step in deionized water and ultrasonically clean it for 15-30 minutes; 3. Place the ITO cleaned in the previous step in ethanol and ultrasonically clean it for 15-30 minutes; 4. Place the ITO cleaned in the previous step in acetone and ultrasonically clean it for 15-30 minutes. After completion, take out the ITO and store it in acetone.

[0051] 2) Assembly of the memristor based on black phosphorus-graphene oxide quantum dots: After drying, prepare a silver electrode by thermal evaporation method. The vacuum degree is 1*10E -4 pa, the evaporation rate is 0.04 nm / s, and the thickness is 20-100 nm. Use mask plates such as circular dots and squares. The diameter of the circular dot mask plate is 1 mm, and the pore size of the square mask plate is 1×1 mm. Finally, obtain a silver / graphene oxide / black phosphorus-graphene oxide quantum dots / graphene oxide / ITO memristor device.

[0052] The ITO conductive glass in step 1) can also be replaced with flexible PET ITO, so as to realize the preparation of a flexible graphene oxide / black phosphorus-graphene oxide quantum dot / graphene oxide memristor.

[0053] The thermal evaporation method in step 2) can also be replaced with electron beam evaporation, and silver can be replaced with ITO, so as to realize the preparation of a light-regulated graphene oxide / black phosphorus-graphene oxide quantum dot / graphene oxide memristor.

[0054] Example 1

[0055] Preparation of graphene oxide / black phosphorus-graphene oxide quantum dot / graphene oxide film:

[0056] (1) Preparation of black phosphorus nanosheet solution: Take 100 mg of single-crystal black phosphorus bulk material, grind it in a mortar for 10 minutes in a glove box, and then put it into a vacuum ball milling tank together with stainless steel balls. After connecting the air pump to evacuate, ball mill it for 4 hours, with a ball-to-material ratio of 100:1 and a ball milling speed of 200 revolutions per minute. Take out the ball-milled black phosphorus in the glove box and ultrasonically disperse it in isopropanol solution. The conditions for ultrasonic dispersion are: the solution temperature is 4 °C, the ultrasonic power is 500 W, the ultrasonic time is 6 hours, and the ultrasonic environment is a dark room. Then centrifuge it with a high-speed centrifuge at a speed of 10,000 revolutions per minute. After centrifugation, take the supernatant of the solution to obtain a monolayer black phosphorus nanosheet solution with a uniform size distribution;

[0057] (2) Preparation of graphene oxide nanosheet solution: Weigh 100 mg of purchased monolayer graphene oxide nanosheets, add 100 mL of deionized water, and prepare a graphene oxide dispersion by ultrasonic dispersion. The conditions for ultrasonic dispersion are: the solution temperature is 4 °C, the ultrasonic power is 500 W, the ultrasonic time is 2 hours, and the ultrasonic environment is a dark room. Then centrifuge it with a high-speed centrifuge at a speed of 3,000 revolutions per minute. After centrifugation, take the supernatant of the solution to obtain a monolayer graphene oxide nanosheet solution;

[0058] (3) Preparation of graphene oxide quantum dot solution: Add 0.5 mL of hydrogen peroxide (30%) solution to a certain amount of the solution obtained in step (2) to make a mixed solution, and then carry out a photo-Fenton reaction under irradiation with a 365-nm ultraviolet lamp (power of 5 W). The reaction preparation parameters are: the magnetic stirring speed is 50 revolutions, the stirring time is 40 minutes. After completion, put it into a dialysis bag with a molecular weight cut-off of 3500 Da and dialyze for 2 days to obtain a monolayer graphene oxide quantum dot solution with a diameter of about 10 nm;

[0059] (4) Preparation of black phosphorus-graphene oxide quantum dot mixed solution: Mix the solutions obtained in steps (1) and (3) in a beaker at a ratio of 1:1, and use magnetic stirring to stir for 5 minutes at a speed of 20 revolutions per minute to fully mix them;

[0060] (5) Preparation of graphene oxide / black phosphorus-graphene oxide quantum dot / graphene oxide hierarchical functional film: Use a vacuum filtration device and a water-based filter membrane with a pore size of 22 microns to sequentially filter 5 ml of the solutions obtained in steps (2), (4), and (2). The filtration pressure is 0.85 Mpa. After completion, take out the filter membrane and place it in a vacuum drying oven for drying. The vacuum degree is 0.08 Mpa, and the drying temperature is 60 °C. By controlling the amount of each solution, a film with a thickness of 100 nm for each of the upper, middle, and lower layers can be obtained, and the overall thickness of the film is 300 nm.

[0061] Preparation of memristor with black phosphorus-graphene oxide quantum dots:

[0062] 1) Transfer of graphene oxide / black phosphorus-graphene oxide quantum dot / graphene oxide functional film: Cut the graphene oxide / black phosphorus-graphene oxide quantum dot / graphene oxide film with the filter membrane prepared in step (5) into a size of 2*2 cm, and transfer it to the surface of a 2*2 cm ITO conductive glass that has been cleaned by oxygen plasma after being wetted with isopropanol. Apply a certain pressure to make the surface of the graphene oxide / black phosphorus-graphene oxide quantum dot / graphene oxide film closely contact the ITO surface. After the transfer is completed, drop acetone onto the filter membrane to dissolve the filter membrane. The dropping speed of acetone is 1 drop / second, and the angle between the graphene oxide / black phosphorus-graphene oxide quantum dot / graphene oxide film and the horizontal plane is 10 degrees. This can make acetone flow smoothly and prevent acetone from accumulating. After the filter membrane is completely dissolved, the graphene oxide / black phosphorus-graphene oxide quantum dot / graphene oxide film transferred to the ITO substrate can be obtained. Then, place the film in a vacuum drying oven for drying, and the vacuum degree is 0.08 Mpa. The sheet resistance of ITO < 7 Ohm / sq. The surface cleaning process used for ITO cleaning is as follows: 1. Use a cleaning agent to clean and remove the oil stain on the ITO surface, and rinse it with tap water after cleaning; 2. Place the ITO cleaned in the previous step in deionized water and ultrasonically clean it for 15 minutes; 3. Place the ITO cleaned in the previous step in ethanol and ultrasonically clean it for 15 minutes; 4. Place the ITO cleaned in the previous step in acetone and ultrasonically clean it for 15 minutes. After completion, take out the ITO and store it in acetone.

[0063] 2) Assembly of the memristor based on black phosphorus-graphene oxide quantum dots: After drying, a silver electrode was prepared by thermal evaporation method with a vacuum degree of 1*10E-4 pa, an evaporation rate of 0.04 nm / s, and a thickness of 20 nm. Using mask plates such as dot-shaped and square-shaped ones, the diameter of the dot-shaped mask plate was 1 mm, and the pore size of the square-shaped mask plate was 1×1 mm. Finally, a silver / graphene oxide / black phosphorus-graphene oxide quantum dots / graphene oxide / ITO memristor device was obtained.

[0064] Example 2

[0065] Preparation of graphene oxide / black phosphorus-graphene oxide quantum dots / graphene oxide film:

[0066] (1) Preparation of black phosphorus nanosheet solution: Take 500 mg of single-crystal black phosphorus bulk material, grind it in a mortar for 30 minutes in a glove box, and then put it into a vacuum ball mill tank together with stainless steel balls. After connecting the air pump to evacuate, ball mill it for 24 hours with a ball-to-material ratio of 1000:1 and a ball mill rotation speed of 400 rpm. Take out the ball-milled black phosphorus in the glove box and ultrasonically disperse it in an isopropyl alcohol solution. Ultrasonic dispersion conditions: solution temperature is 4 °C, ultrasonic power is 1000 W, ultrasonic time is 12 hours, and ultrasonic environment is a dark room. Then centrifuge it through a high-speed centrifuge at a speed of 12000 rpm. After centrifugation, take the supernatant of the solution to obtain a monolayer black phosphorus nanosheet solution with uniform size distribution;

[0067] (2) Preparation of graphene oxide nanosheet solution: Weigh 500 mg of purchased monolayer graphene oxide nanosheets and add 500 mL of deionized water to prepare a graphene oxide dispersion by ultrasonic dispersion. Ultrasonic dispersion conditions: solution temperature is 4 °C, ultrasonic power is 1000 W, ultrasonic time is 6 hours, and ultrasonic environment is a dark room. Then centrifuge it through a high-speed centrifuge at a speed of 12000 rpm. After centrifugation, take the supernatant of the solution to obtain a monolayer graphene oxide nanosheet solution;

[0068] (3) Preparation of graphene oxide quantum dot solution: Add 2 mL of hydrogen peroxide (30%) solution to a certain amount of the solution obtained in step (2) to make a mixed solution, and then carry out a photo-Fenton reaction under ultraviolet light irradiation with a wavelength of 365 nm (power of 20 W). Reaction preparation parameters: magnetic stirring speed is 200 rpm, stirring time is 60 minutes. After completion, put it into a dialysis bag with a molecular weight cut-off of 3500 Da and dialyze for 3 days to obtain a monolayer graphene oxide quantum dot solution with a diameter of 10 nm;

[0069] (4) Preparation of black phosphorus-graphene oxide quantum dot mixed solution: Mix the solutions obtained in steps (1) and (3) in a beaker at a ratio of 1:1, and use magnetic stirring to stir at a speed of 100 rpm for 10 minutes to make them fully mixed;

[0070] (5) Preparation of graphene oxide / black phosphorus-graphene oxide quantum dot / graphene oxide hierarchical functional film: Using a vacuum filtration device and a water-based filter membrane with a pore size of 22 microns, sequentially filter 10 ml of the solutions obtained in steps (2), (4), and (2). The filtration pressure is 0.95 Mpa. After completion, take out the filter membrane and place it in a vacuum drying oven for drying. The vacuum degree is 0.08 Mpa, and the drying temperature is 60 °C. By controlling the amount of each solution, a film with a thickness of 250 nm for each of the upper, middle, and lower layers can be obtained, and the overall thickness of the film is 750 nm.

[0071] Preparation of memristor based on black phosphorus-graphene oxide quantum dots:

[0072] 1) Transfer of graphene oxide / black phosphorus-graphene oxide quantum dot / graphene oxide functional film: Cut a 2*2 cm-sized graphene oxide / black phosphorus-graphene oxide quantum dot / graphene oxide film with a filter membrane prepared in step (5). After wetting with isopropanol, transfer it to the surface of a 2*2 cm-sized ITO conductive glass that has been cleaned by oxygen plasma. Apply a certain pressure to make the graphene oxide / black phosphorus-graphene oxide quantum dot / graphene oxide film surface closely contact the ITO surface. After the transfer is completed, drop acetone onto the filter membrane to dissolve the filter membrane. The dropping speed of acetone is 4 drops / second, and the angle between the graphene oxide / black phosphorus-graphene oxide quantum dot / graphene oxide film and the horizontal plane is 30 degrees. This can make the acetone flow smoothly and prevent the acetone from accumulating. After the filter membrane is completely dissolved, the graphene oxide / black phosphorus-graphene oxide quantum dot / graphene oxide film transferred to the ITO substrate can be obtained. Then, place the film in a vacuum drying oven for drying, and the vacuum degree is 0.08 Mpa. The sheet resistance of ITO < 7 Ohm / sq. The surface cleaning process used for ITO cleaning is as follows: 1. Use a cleaning agent to clean and remove the oil stain on the ITO surface, and then rinse it with tap water after cleaning; 2. Put the ITO cleaned in the previous step into deionized water and ultrasonically clean it for 30 minutes; 3. Put the ITO cleaned in the previous step into ethanol and ultrasonically clean it for 30 minutes; 4. Put the ITO cleaned in the previous step into acetone and ultrasonically clean it for 30 minutes. After completion, take out the ITO and store it in acetone.

[0073] 2) Assembly of memristor based on black phosphorus-graphene oxide quantum dots: After drying, prepare a silver electrode by thermal evaporation method. The vacuum degree is 1*10E -4 pa, the evaporation rate is 0.04 nm / s, and the thickness is 100 nm. Use mask plates such as dot-shaped and square-shaped. The diameter of the dot-shaped mask plate is 1 mm, and the pore size of the square-shaped mask plate is 1×1 mm. Finally, obtain a silver / graphene oxide / black phosphorus-graphene oxide quantum dot / graphene oxide / ITO memristor device.

[0074] Example 3

[0075] Preparation of graphene oxide / black phosphorus-graphene oxide quantum dots / graphene oxide film:

[0076] (1) Preparation of black phosphorus nanosheet solution: Take 500 mg of single-crystal black phosphorus bulk material, grind it in a mortar for 30 minutes in a glove box, then put it into a vacuum ball milling tank together with stainless steel balls. After connecting to an air pump to evacuate, ball mill it for 24 hours with a ball-to-material ratio of 1000:1 and a ball milling speed of 400 revolutions per minute. Take out the ball-milled black phosphorus in the glove box and ultrasonically disperse it in isopropyl alcohol solution. The conditions for ultrasonic dispersion are: the solution temperature is 4 °C, the ultrasonic power is 1000 W, the ultrasonic time is 12 hours, and the ultrasonic environment is a dark room. Then centrifuge it with a high-speed centrifuge at a speed of 12000 revolutions per minute. After centrifugation, take the supernatant of the solution to obtain a monolayer black phosphorus nanosheet solution with uniform size distribution;

[0077] (2) Preparation of graphene oxide nanosheet solution: Weigh 500 mg of purchased monolayer graphene oxide nanosheets and add 500 mL of deionized water to prepare a graphene oxide dispersion by ultrasonic dispersion. The conditions for ultrasonic dispersion are: the solution temperature is 4 °C, the ultrasonic power is 1000 W, the ultrasonic time is 6 hours, and the ultrasonic environment is a dark room. Then centrifuge it with a high-speed centrifuge at a speed of 12000 revolutions per minute. After centrifugation, take the supernatant of the solution to obtain a monolayer graphene oxide nanosheet solution;

[0078] (3) Preparation of graphene oxide quantum dot solution: Add 2 mL of hydrogen peroxide (30%) solution to a certain amount of the solution obtained in step (2) to make a mixed solution, and then carry out a photo-Fenton reaction under ultraviolet light irradiation with a wavelength of 365 nm (power of 20 W). The reaction preparation parameters are: the magnetic stirring speed is 200 revolutions, the stirring time is 60 minutes. After completion, put it into a dialysis bag with a molecular weight cut-off of 3500 Da and dialyze for 3 days to obtain a monolayer graphene oxide quantum dot solution with a diameter of 10 nm;

[0079] (4) Preparation of black phosphorus-graphene oxide quantum dot mixed solution: Mix the solutions obtained in steps (1) and (3) in a beaker in a ratio of 1:1, and use magnetic stirring to stir at a speed of 100 revolutions per minute for 10 minutes to make them fully mixed;

[0080] (5) Preparation of graphene oxide / black phosphorus-graphene oxide quantum dot / graphene oxide hierarchical functional film: Using a vacuum filtration device and a water-based filter membrane with a pore size of 22 microns, sequentially filter 10 ml of the solutions obtained in step (2), step (4), and step (2). The filtration pressure is 0.95 Mpa. After completion, take out the filter membrane and place it in a vacuum drying oven for drying. The vacuum degree is 0.08 Mpa, and the drying temperature is 60 °C. By controlling the amount of each solution, a film with a thickness of 250 nm for each of the upper, middle, and lower layers can be obtained, and the overall thickness of the film is 750 nm.

[0081] Preparation of flexible memristor based on black phosphorus-graphene oxide quantum dots:

[0082] 1) Transfer of graphene oxide / black phosphorus-graphene oxide quantum dot / graphene oxide functional film: Cut a 2*2 cm-sized graphene oxide / black phosphorus-graphene oxide quantum dot / graphene oxide film with a filter membrane prepared in step (5). After wetting with isopropyl alcohol, transfer it to the surface of a 2*2 cm-sized PETITO that has been cleaned by oxygen plasma. Apply a certain pressure to make the surface of the graphene oxide / black phosphorus-graphene oxide quantum dot / graphene oxide film closely contact the PETITO surface. After the transfer is completed, drop acetone onto the filter membrane to dissolve the filter membrane. The dropping rate of acetone is 4 drops / second, and the angle between the graphene oxide / black phosphorus-graphene oxide quantum dot / graphene oxide film and the horizontal plane is 30 degrees. This can make acetone flow smoothly and prevent acetone from accumulating. After the filter membrane is completely dissolved, the graphene oxide / black phosphorus-graphene oxide quantum dot / graphene oxide film transferred to the PETITO substrate can be obtained. Then, place the film in a vacuum drying oven for drying, with a vacuum degree of 0.08 Mpa. The sheet resistance of PETITO < 7 Ohm / sq. The surface cleaning process used for PETITO cleaning is as follows: 1. Use a cleaning agent to clean the oil stain on the PETITO surface, and after cleaning, rinse it with tap water; 2. Put the PETITO cleaned in the previous step into deionized water and ultrasonically clean it for 30 minutes; 3. Put the PETITO cleaned in the previous step into ethanol and ultrasonically clean it for 30 minutes; 4. Put the PETITO cleaned in the previous step into acetone and ultrasonically clean it for 30 minutes. After completion, take out the PETITO and store it in acetone.

[0083] 2) Assembly of memristor based on black phosphorus-graphene oxide quantum dots: After drying, prepare silver electrodes by thermal evaporation method. The vacuum degree is 1*10E -4 pa, the evaporation rate is 0.04 nm / s, and the thickness is 100 nm. Use mask plates such as circular dots and squares. The diameter of the circular dot mask plate is 1 mm, and the pore size of the square mask plate is 1×1 mm. Finally, obtain a silver / graphene oxide / black phosphorus-graphene oxide quantum dot / graphene oxide / ITO flexible memristor device.

[0084] Example 4

[0085] Preparation of graphene oxide / black phosphorus-graphene oxide quantum dots / graphene oxide film:

[0086] (1) Preparation of black phosphorus nanosheet solution: Take 500 mg of single-crystal black phosphorus bulk material, grind it in a mortar for 30 minutes in a glove box, then put it into a vacuum ball mill tank together with stainless steel balls. After connecting the air pump to evacuate, ball mill it for 24 hours with a ball-to-material ratio of 1000:1 and a ball mill rotation speed of 400 revolutions per minute. Take out the ball-milled black phosphorus in the glove box and ultrasonically disperse it in an isopropyl alcohol solution. Ultrasonic dispersion conditions: solution temperature is 4 °C, ultrasonic power is 1000 W, ultrasonic time is 12 hours, and the ultrasonic environment is a dark room. Then centrifuge it with a high-speed centrifuge at a speed of 12000 revolutions per minute. After centrifugation, take the supernatant of the solution to obtain a single-layer black phosphorus nanosheet solution with uniform size distribution;

[0087] (2) Preparation of graphene oxide nanosheet solution: Weigh 500 mg of purchased single-layer graphene oxide nanosheets, add 500 mL of deionized water, and prepare a graphene oxide dispersion by ultrasonic dispersion. Ultrasonic dispersion conditions: solution temperature is 4 °C, ultrasonic power is 1000 W, ultrasonic time is 6 hours, and the ultrasonic environment is a dark room. Then centrifuge it with a high-speed centrifuge at a speed of 12000 revolutions per minute. After centrifugation, take the supernatant of the solution to obtain a single-layer graphene oxide nanosheet solution;

[0088] (3) Preparation of graphene oxide quantum dot solution: Add 2 mL of hydrogen peroxide (30%) solution to a certain amount of the solution obtained in step (2) to make a mixed solution, and then carry out a photo-Fenton reaction under ultraviolet light irradiation with a wavelength of 365 nm (power of 20 W). Reaction preparation parameters: magnetic stirring speed is 200 revolutions, stirring time is 60 minutes. After completion, put it into a dialysis bag with a molecular weight cut-off of 3500 Da and dialyze for 3 days to obtain a single-layer graphene oxide quantum dot solution with a diameter of 10 nm;

[0089] (4) Preparation of black phosphorus-graphene oxide quantum dot mixed solution: Mix the solutions obtained in steps (1) and (3) in a beaker in a ratio of 1:1, and use magnetic stirring to stir at a speed of 100 revolutions per minute for 10 minutes to make them fully mixed;

[0090] (5) Preparation of graphene oxide / black phosphorus-graphene oxide quantum dot / graphene oxide hierarchical functional film: Using a vacuum filtration device and a water-based filter membrane with a pore size of 22 microns, sequentially filter 10 ml of the solutions obtained in step (2), step (4), and step (2). The filtration pressure is 0.95 Mpa. After completion, take out the filter membrane and place it in a vacuum drying oven for drying. The vacuum degree is 0.08 Mpa, and the drying temperature is 60 °C. By controlling the amount of each solution, a film with a thickness of 250 nm for each of the upper, middle, and lower layers can be obtained, and the overall thickness of the film is 750 nm.

[0091] Preparation of a photoresistor based on black phosphorus-graphene oxide quantum dots:

[0092] 1) Transfer of graphene oxide / black phosphorus-graphene oxide quantum dot / graphene oxide functional film: Cut a 2*2 cm-sized graphene oxide / black phosphorus-graphene oxide quantum dot / graphene oxide film with a filter membrane prepared in step (5). After wetting with isopropanol, transfer it to the surface of a 2*2 cm-sized ITO conductive glass that has been cleaned by oxygen plasma. Apply a certain pressure to closely contact the surface of the graphene oxide / black phosphorus-graphene oxide quantum dot / graphene oxide film with the ITO surface. After the transfer is completed, drop acetone onto the filter membrane to dissolve the filter membrane. The dropping speed of acetone is 4 drops / second, and the angle between the graphene oxide / black phosphorus-graphene oxide quantum dot / graphene oxide film and the horizontal plane is 30 degrees. This can make acetone flow smoothly and prevent acetone from accumulating. After the filter membrane is completely dissolved, the graphene oxide / black phosphorus-graphene oxide quantum dot / graphene oxide film transferred to the ITO substrate can be obtained. Then, place the film in a vacuum drying oven for drying, and the vacuum degree is 0.08 Mpa. The sheet resistance of ITO < 7 Ohm / sq. The surface cleaning process used for ITO cleaning is as follows: 1. Use a cleaning agent to clean and remove the oil stain on the ITO surface, and then rinse it with tap water after cleaning; 2. Put the ITO cleaned in the previous step into deionized water and ultrasonically clean it for 30 minutes; 3. Put the ITO cleaned in the previous step into ethanol and ultrasonically clean it for 30 minutes; 4. Put the ITO cleaned in the previous step into acetone and ultrasonically clean it for 30 minutes. After completion, take out the ITO and store it in acetone.

[0093] 2) Assembly of the resistor based on black phosphorus-graphene oxide quantum dots: After drying, prepare a transparent ITO electrode by electron beam evaporation. The vacuum degree is 1*10E -4 pa, the evaporation rate is 0.04 nm / s, and the thickness is 100 nm. Use mask plates such as circular dots and squares. The diameter of the circular dot mask plate is 1 mm, and the pore size of the square mask plate is 1×1 mm. Finally, obtain an ITO / graphene oxide / black phosphorus-graphene oxide quantum dot / graphene oxide / ITO photoresistor device.

[0094] Example 5

[0095] Preparation of Graphene Oxide / Black Phosphorus-Graphene Oxide Quantum Dots / Graphene Oxide Film:

[0096] (1) Preparation of black phosphorus nanosheet solution: Take 500 mg of single-crystal black phosphorus bulk material, grind it in a mortar for 30 minutes in a glove box, then put it into a vacuum ball milling tank together with stainless steel balls. After connecting to an air pump to evacuate the air, ball mill it for 24 hours with a ball-to-material ratio of 1000:1 and a ball milling speed of 400 revolutions per minute. Take out the ball-milled black phosphorus in the glove box and ultrasonically disperse it in an isopropanol solution. The conditions for ultrasonic dispersion are: the solution temperature is 4 °C, the ultrasonic power is 1000 W, the ultrasonic time is 12 hours, and the ultrasonic environment is a dark room. Then centrifuge it with a high-speed centrifuge at a speed of 12000 revolutions per minute. After centrifugation, take the supernatant of the solution to obtain a monolayer black phosphorus nanosheet solution with a uniform size distribution;

[0097] (2) Preparation of graphene oxide nanosheet solution: Weigh 500 mg of purchased monolayer graphene oxide nanosheets, add 500 mL of deionized water, and prepare a graphene oxide dispersion by ultrasonic dispersion. The conditions for ultrasonic dispersion are: the solution temperature is 4 °C, the ultrasonic power is 1000 W, the ultrasonic time is 6 hours, and the ultrasonic environment is a dark room. Then centrifuge it with a high-speed centrifuge at a speed of 12000 revolutions per minute. After centrifugation, take the supernatant of the solution to obtain a monolayer graphene oxide nanosheet solution;

[0098] (3) Preparation of graphene oxide quantum dot solution: Add 2 mL of hydrogen peroxide (30%) solution to a certain amount of the solution obtained in step (2) to make a mixed solution, and then carry out a photo-Fenton reaction under irradiation with a 365-nm ultraviolet lamp (power of 20 W). The reaction preparation parameters are: the magnetic stirring speed is 200 revolutions, the stirring time is 60 minutes. After completion, put it into a dialysis bag with a molecular weight cut-off of 3500 Da and dialyze for 3 days to obtain a monolayer graphene oxide quantum dot solution with a diameter of 10 nm;

[0099] (4) Preparation of black phosphorus-graphene oxide quantum dot mixed solution: Mix the solutions obtained in steps (1) and (3) in a beaker in a 1:1 ratio, and use magnetic stirring to stir at a speed of 100 revolutions per minute for 10 minutes to make them fully mixed;

[0100] (5) Preparation of graphene oxide / black phosphorus-graphene oxide quantum dots / graphene oxide hierarchical functional film: Using a vacuum filtration device and a water-based filter membrane with a pore size of 22 microns, sequentially filter 10 ml of the solutions obtained in steps (2), (4), and (2). The filtration pressure is 0.95 Mpa. After completion, take out the filter membrane and place it in a vacuum drying oven for drying. The vacuum degree is 0.08 Mpa, and the drying temperature is 60 °C. By controlling the amount of each solution, a film with a thickness of 250 nm for each of the upper, middle, and lower layers can be obtained, and the overall thickness of the film is 750 nm.

[0101] Preparation of flexible photoresistor based on black phosphorus-graphene oxide quantum dots:

[0102] 1) Transfer of graphene oxide / black phosphorus-graphene oxide quantum dots / graphene oxide functional film: Cut a 2*2 cm-sized graphene oxide / black phosphorus-graphene oxide quantum dots / graphene oxide film with a filter membrane prepared in step (5). After wetting with isopropyl alcohol, transfer it to the surface of a 2*2 cm-sized ITO conductive glass that has been cleaned by oxygen plasma. Apply a certain pressure to closely contact the surface of the graphene oxide / black phosphorus-graphene oxide quantum dots / graphene oxide film with the PETITO surface. After the transfer is completed, drop acetone onto the filter membrane to dissolve the filter membrane. The dropping rate of acetone is 4 drops / second, and the angle between the graphene oxide / black phosphorus-graphene oxide quantum dots / graphene oxide film and the horizontal plane is 30 degrees. This can make the acetone flow smoothly and prevent the acetone from aggregating. After the filter membrane is completely dissolved, the graphene oxide / black phosphorus-graphene oxide quantum dots / graphene oxide film transferred to the PETITO substrate can be obtained. Then, place the film in a vacuum drying oven for drying, with a vacuum degree of 0.08 Mpa. The sheet resistance of PETITO < 7 Ohm / sq. The surface cleaning process used for ITO cleaning is as follows: 1. Use a cleaning agent to clean and remove the oil stains on the surface of PETITO, and then rinse it with tap water after cleaning; 2. Place the PETITO cleaned in the previous step in deionized water and ultrasonically clean it for 30 minutes; 3. Place the PETITO cleaned in the previous step in ethanol and ultrasonically clean it for 30 minutes; 4. Place the PETITO cleaned in the previous step in acetone and ultrasonically clean it for 30 minutes. After completion, take out the ITO and store it in acetone.

[0103] 2) Assembly of the resistor based on black phosphorus-graphene oxide quantum dots: After drying, prepare a transparent ITO electrode by electron beam evaporation method. The vacuum degree is 1*10E -4 pa, the evaporation rate is 0.04 nm / s, and the thickness is 100 nm. Use mask plates such as circular dots and squares. The diameter of the circular dot mask plate is 1 mm, and the pore size of the square mask plate is 1×1 mm. Finally, obtain a silver / graphene oxide / black phosphorus-graphene oxide quantum dots / graphene oxide / ITO flexible photoresistor device.

[0104] Figure 1 Figure for the digital photo of the device in Example 2. It can be seen from the photo that the device array can be rapidly prepared by the method of the present invention, and the density of the device array can be changed by altering the size of the mask.

[0105] Figure 2 SEM cross-sectional view of the device in Example 2. It can be seen from the figure the layered structures of black phosphorus and graphene oxide. In the middle layer, graphene oxide quantum dots with dot-like structures can be clearly seen. The overall thickness of the device is about 750 nm.

[0106] Figure 3 Schematic diagram of the memristor structure of black phosphorus-graphene oxide quantum dots. The schematic diagram corresponds to Figure 2 the SEM cross-sectional view, which can more intuitively display the device structure.

[0107] Figure 4 Schematic diagram of the connection of two black phosphorus-graphene oxide quantum dot memristors, that is, by connecting the bottom electrodes (ITO electrodes) of the two memristors to form a mechanism with two inputs and one output, to simulate the structure and function of dendritic nerves.

[0108] Figure 5 Double-pulse potentiation test for Example 2. Double-pulse potentiation is used as a benchmark test for synaptic devices. The black phosphorus-graphene oxide quantum dot memristor prepared by the method of the present invention can well simulate double-pulse potentiation, indicating that we have successfully fabricated a black phosphorus-graphene oxide quantum dot artificial synaptic device.

[0109] Figure 6 Long-term memory test for Example 2. By increasing the number of pulses, the postsynaptic current of the black phosphorus-graphene oxide quantum dot artificial synapse can be significantly increased, which is in line with the transition of the synapse from short-term memory (STM) to long-term memory (LTM).

[0110] Figure 7 STDP test for Example 2. With the change of the time interval between the presynaptic stimulus and the postsynaptic stimulus, the change of the synaptic weight is obvious. When Δt > 0, synaptic potentiation is shown, and when Δt < 0, synaptic depression is shown.

[0111] Figure 8 Logic "AND" test for Example 2. At a low bias voltage (0.1 V), the signals triggered by neuron 1 and neuron 2 alone cannot exceed the threshold (110 nA). When the two neurons are triggered simultaneously, the obtained signal exceeds the threshold, realizing the simulation of the logic "AND" function.

[0112] Figure 9For the logic "OR" test of Example 2, under a high bias voltage (0.5V), the signals triggered by neuron 1 and neuron 2 can exceed the threshold (110nA) individually. When the two neurons are triggered at the same time, the resulting signal also exceeds the threshold, realizing the simulation of the logic "OR" function.

[0113] Figure 10 In the "Pavlov" conditional firing test of Example 2, a 1V pulse is used as a ringing stimulus to act on neuron 1, and a 6V pulse is used as a food stimulus to act on neuron 2. It can be seen that the signal triggered by neuron 1 did not reach the set threshold (20nA), and the signal triggered by neuron 2 exceeded the threshold. Through training (triggering the signals of neuron 1 and neuron 2 at the same time), it was found that the signal also exceeded the threshold. After the training was completed, neuron 1 was triggered alone, and the triggered signal greatly exceeded the threshold. After that, the number of training was increased, and neuron 1 was triggered alone again. At this time, the triggered signal became higher.

[0114] Figure 11 In the double pulse test of Example 2 after the device was placed in the air for 3 months, the device can still simulate the double pulse alienation well, indicating that the black phosphorus-graphene oxide quantum dot artificial synapse prepared by the inventive method has good air stability.

[0115] Figure 12 The device of Example 2 was placed in the air for 3 months and subjected to 10 pulse tests. The device can still well simulate the transition of the synapse from short-term memory (STM) to long-term memory (LTM), indicating that the black phosphorus-graphene oxide quantum dot artificial synapse prepared by the method of the present invention has good air stability.

[0116] It can be seen from the above examples that the memristor based on black phosphorus-graphene oxide quantum dots prepared by the present invention has a simple structure, is easy to prepare, has low cost, simple process, and good scalability. The most important thing is that it can well simulate the basic functions of biological synapses and the information logic processing capabilities between multiple neurons. Therefore, it can be applied to the field of artificial intelligence, and the method can be used in the fields of artificial neural networks, etc., and has broad application prospects.

Claims

1. A thin film based on black phosphorus-reduced graphene oxide quantum dots, Characterized in that, It includes an upper structure, a middle structure and a lower structure connected together in sequence. The materials of the upper structure and the lower structure are both reduced graphene oxide nanosheets, and the material of the middle structure is a black phosphorus-reduced graphene oxide quantum dot composite.

2. The thin film based on black phosphorus-reduced graphene oxide quantum dots according to claim 1, Characterized in that, The thicknesses of the upper structure, the middle structure and the lower structure are all 100 - 250 nanometers.

3. The thin film based on black phosphorus-reduced graphene oxide quantum dots according to claim 1, Characterized in that, In the black phosphorus-reduced graphene oxide quantum dot composite, the mass ratio of black phosphorus to reduced graphene oxide quantum dots is 1:

1.

4. A preparation method of the thin film based on black phosphorus-reduced graphene oxide quantum dots according to any one of claims 1 - 3, Characterized in that, It includes: (1) Mix the black phosphorus nanosheet solution and the reduced graphene oxide quantum dot solution evenly to obtain a black phosphorus-reduced graphene oxide quantum dot mixed solution; (2) Use a vacuum filtration device and a filter membrane to sequentially filter the reduced graphene oxide nanosheet solution, the black phosphorus-reduced graphene oxide quantum dot mixed solution and the reduced graphene oxide nanosheet solution. After the filtration is completed, vacuum dry the filter membrane to obtain a thin film based on black phosphorus-reduced graphene oxide quantum dots loaded on the filter membrane.

5. The preparation method of the thin film based on black phosphorus-reduced graphene oxide quantum dots according to claim 4, Characterized in that, In step (1), the size of the black phosphorus nanosheets in the black phosphorus nanosheet solution is 200 nanometers to 2 micrometers, and the diameter size of the reduced graphene oxide quantum dots in the reduced graphene oxide quantum dot solution is 5 - 10 nm; in step (2), the size of the reduced graphene oxide nanosheets in the reduced graphene oxide nanosheet solution is 200 nanometers to 2 micrometers.

6. The preparation method of the thin film based on black phosphorus-reduced graphene oxide quantum dots according to claim 4, Characterized in that, In step (1), the preparation of the reduced graphene oxide quantum dot solution: Add the hydrogen peroxide solution to the reduced graphene oxide nanosheet solution to make a mixed solution, and then carry out a photo-Fenton reaction under the irradiation of a 365-nanometer ultraviolet lamp. After the reaction is completed, dialyze to obtain the reduced graphene oxide quantum dot solution.

7. A memristor based on black phosphorus-reduced graphene oxide quantum dots, Characterized in that, It includes the thin film based on black phosphorus-reduced graphene oxide quantum dots according to any one of claims 1 - 3.

8. A preparation method of the memristor based on black phosphorus-reduced graphene oxide quantum dots according to claim 7, Characterized in that, It includes: (1) Mix the black phosphorus nanosheet solution and the reduced graphene oxide quantum dot solution evenly to obtain a black phosphorus-reduced graphene oxide quantum dot mixed solution; (2) Use a vacuum filtration device and a filter membrane to sequentially filter the reduced graphene oxide nanosheet solution, the black phosphorus-reduced graphene oxide quantum dot mixed solution and the reduced graphene oxide nanosheet solution. After the filtration is completed, vacuum dry the filter membrane to obtain a thin film based on black phosphorus-reduced graphene oxide quantum dots with the filter membrane; (3) Wet the black phosphorus-graphene quantum dot-based film with the filter membrane using isopropanol, then transfer it to the conductive substrate, and apply pressure to closely contact the surface of the black phosphorus-graphene quantum dot-based film with the surface of the conductive substrate. After the transfer is completed, drop acetone onto the filter membrane to dissolve the filter membrane. After the filter membrane is completely dissolved, dry it under vacuum to obtain the black phosphorus-graphene quantum dot-based film transferred to the conductive substrate; (4) Assemble the black phosphorus-graphene quantum dot-based film transferred to the conductive substrate with the second electrode to prepare a memristor.

9. The method for preparing a memristor based on black phosphorus-graphene quantum dots according to claim 8, characterized in that, in step (3), the conductive substrate is ITO conductive glass or flexible PETITO.

10. The method for preparing a memristor based on black phosphorus-graphene quantum dots according to claim 8, characterized in that, in step (4), the second electrode is a silver electrode or ITO conductive glass.

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