Van der waals contact perovskite single crystal press sheet memristor and preparation method thereof

Abstract

The application discloses a van der Waals contact perovskite single crystal wafer memristor and a preparation method thereof. The preparation method of the van der Waals contact perovskite single crystal wafer memristor comprises the following steps: S1, using a perovskite precursor solution, a perovskite bulk single crystal is prepared by an inverse temperature crystallization method; S2, the perovskite bulk single crystal is ground and pressed into a perovskite single crystal wafer; S3, a thermal release layer is prepared on the perovskite single crystal wafer by using a thermal release material; S4, an electrode is evaporated on the thermal release layer, and then the thermal release layer is removed by a thermal decomposition method, thereby obtaining the van der Waals contact perovskite single crystal wafer memristor. The thermal release material is a 1wt. %-5wt. % polycarbonate solution. The preparation method greatly shortens the preparation period of the halide hybrid perovskite single crystal, unifies the thickness and shape of a large number of prepared halide hybrid perovskite single crystals, and the memristor prepared by the method has the advantage of low energy consumption.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of memory storage and brain-like neural morphological computing, and more particularly to a van der Waals contact perovskite single crystal press sheet memristor and a preparation method thereof. BACKGROUND

[0002] In new electronic devices, memristors have the advantages of non-volatility, low power consumption and high integration, and are considered to have wide application prospects in the fields of data storage, logical operation and brain-like neural morphological computing. In recent years, halide hybrid perovskite has been widely used in the field of optoelectronics due to its high light absorption coefficient and large carrier mobility. In addition, as an ionic crystal, the current hysteresis phenomenon caused by the ion migration effect and the nonlinear variable resistance effect of the memristor under the action of an external electric field are well matched. Therefore, halide hybrid perovskite can be used as the functional layer of a memristor.

[0003] Perovskite single crystals generally have low defect density due to the absence of grain boundaries and structural uniformity, which is beneficial to improving the mobility and lifetime of carriers and thus enhancing the optoelectronic performance of the material. Therefore, using halide hybrid perovskite single crystals as the functional layer of a memristor is beneficial to improving the uniformity of array devices. However, the preparation period of conventional halide hybrid perovskite single crystals requires at least one week, and the thickness and shape of the prepared halide hybrid perovskite single crystals are not uniform and difficult to control, which is not conducive to large-scale integration.

[0004] In addition, the metal electrodes of conventional memristors are generally prepared by physical vapor deposition (PVD) processes such as vacuum evaporation and magnetron sputtering. Patent CN115666217A discloses a self-rectifying memristor based on halide hybrid perovskite and a preparation method thereof. A strip-shaped Ag electrode is prepared on the halide hybrid perovskite by a thermal evaporation method. The halide hybrid perovskite, the Ag electrode and the commercial ITO electrode at the bottom constitute a memristor device, realizing the functions of rectification and storage. However, when the electrode is deposited by the PVD process, high-energy particles directly bombard the surface of the halide hybrid perovskite functional layer, generating lattice defects such as vacancies and interstitial atoms in the surface and near-surface regions of the functional layer. These defects may affect the crystal quality and electrical properties of the functional layer, thereby reducing the performance of the memristor and increasing the energy consumption of the memristor.

[0005] Therefore, it is of great economic value to develop a preparation method of a van der Waals contact perovskite single crystal press sheet memristor that can reduce the preparation period of halide hybrid perovskite single crystals, make the thickness and shape of the prepared halide hybrid perovskite single crystals uniform, and reduce the energy consumption of the memristor. SUMMARY

[0006] The present application aims to solve the problems of long preparation period of halide hybrid perovskite single crystals, non-uniform thickness and shape of prepared halide hybrid perovskite single crystals, and high energy consumption of the memristor, and provides a van der Waals contact perovskite single crystal wafer memristor and a preparation method thereof.

[0007] To achieve the above-mentioned object, the technical scheme adopted by the present application is as follows:

[0008] In the first aspect, the present application provides a preparation method of a van der Waals contact perovskite single crystal wafer memristor, comprising the following steps:

[0009] S1. Using a perovskite precursor solution, a perovskite bulk single crystal is prepared by inverse temperature crystallization method;

[0010] S2. The perovskite bulk single crystal is ground and wafered to prepare a perovskite single crystal wafer;

[0011] S3. A thermal release layer is prepared on the perovskite single crystal wafer using a thermal release material;

[0012] S4. An electrode is evaporated on the thermal release layer, and then the thermal release layer is removed by thermal decomposition method, thereby obtaining a van der Waals contact perovskite single crystal wafer memristor;

[0013] The thermal release material is a polypropylene carbonate (PPC) solution with a mass percentage of 1wt.%-5wt.%.

[0014] The preparation method of the van der Waals contact perovskite single crystal wafer memristor of the present application greatly shortens the preparation period of halide hybrid perovskite single crystals, and makes the thickness and shape of a large number of prepared halide hybrid perovskite single crystals uniform, and the memristor prepared by the method has the advantage of low energy consumption.

[0015] Specifically, the perovskite bulk single crystal prepared by the inverse temperature crystallization method is ground into powder and wafered to prepare a perovskite single crystal wafer, since wafering does not require a large area of perovskite single crystal, the preparation period of halide hybrid perovskite single crystals is greatly shortened from at least one week to 1-2 days, and a large number of prepared halide hybrid perovskite single crystals have uniform thickness, shape and weight, which is beneficial to large-scale integration and array preparation.

[0016] By introducing a thermal release layer on the perovskite single crystal wafer, the interface between the electrode and the functional layer (i.e. the perovskite single crystal wafer) of the memristor is directly contacted by van der Waals force, which can effectively prevent the bombardment damage of high-energy particles to the surface of the halide hybrid perovskite functional layer (i.e. the perovskite single crystal wafer) during the evaporation of the electrode, and avoid the generation of lattice defects such as vacancies and interstitial atoms in the surface and near-surface regions of the functional layer, thereby reducing the energy consumption of the memristor.

[0017] Preferably, the thermal release material is a 3wt.% polypropylene carbonate (PPC) solution.

[0018] Preferably, the solvent of the polypropylene carbonate (PPC) solution is at least one of anisole, ethyl acetate, dichloromethane.

[0019] Preferably, the perovskite is at least one of CsPbBr3, CsPbI3, MAPbBr3, CsPbI3.

[0020] Preferably, when the perovskite is CsPbBr3, the perovskite precursor solution contains CsBr and PbBr2 in a molar ratio of 1:(1-2).

[0021] More preferably, when the perovskite is CsPbBr3, the perovskite precursor solution contains CsBr and PbBr2 in a molar ratio of 1:2.

[0022] Preferably, when the perovskite is MAPbBr3, the perovskite precursor solution contains PbBr2 and MABr (methylamine hydrobromide) in a molar ratio of 1:(0.8-1.2).

[0023] More preferably, when the perovskite is MAPbBr3, the perovskite precursor solution contains PbBr2 and MABr (methylamine hydrobromide) in a molar ratio of 1:1.

[0024] Preferably, in step S1, the inverse temperature crystallization method refers to first increasing the temperature of the perovskite precursor solution to precipitate a seed crystal, taking out the seed crystal, and placing it in a new perovskite precursor solution for continuous growth to obtain a perovskite bulk single crystal.

[0025] More preferably, the temperature for precipitating the seed crystal is 80-85℃, and the time is 0.5-2h.

[0026] More preferably, the temperature for continuous growth is 75-85℃, and the time is 24-48h.

[0027] Preferably, in step S2, the pressure for tabletting is 10-25Pa, the temperature is 25-200℃, and the time is 20-60min.

[0028] Preferably, in step S2, the perovskite single crystal tablet is circular with a diameter of 0.5-2cm.

[0029] Preferably, step S3 specifically comprises: spin-coating a thermal release material on the perovskite single crystal tablet, and then performing heat treatment to obtain a thermal release layer.

[0030] More preferably, the spin-coating speed is 2000-3500rpm, and the time is 20-30s.

[0031] More preferably, the temperature of the heat treatment is 90-100 DEG C, and the time is 5-15 min.

[0032] Preferably, in step S4, the material of the electrode is at least one of Au, Ag and Al.

[0033] Preferably, in step S4, the thickness of the electrode is 40-100 nm.

[0034] Preferably, in step S4, the temperature of the thermal decomposition method is 250-300 DEG C, and the time is 20-60 min.

[0035] In a second aspect, the present application provides a van der Waals contact perovskite single crystal pressed sheet memristor prepared by the preparation method of the first aspect.

[0036] Compared with the prior art, the present application has the following beneficial effects:

[0037] The preparation method of the van der Waals contact perovskite single crystal pressed sheet memristor of the present application greatly shortens the preparation period of the halide hybrid perovskite single crystal, unifies the thickness and shape of a large number of halide hybrid perovskite single crystals prepared, and the memristor prepared by the method has the advantage of low energy consumption.

[0038] Specifically, the present application grinds the perovskite bulk single crystal prepared by the inverse temperature crystallization method into powder and presses it into a perovskite single crystal pressed sheet. Since the pressed sheet does not require a large area of perovskite single crystal, the preparation period of the halide hybrid perovskite single crystal is greatly shortened from at least one week to 1-2 days, and the thickness, shape and weight of a large number of halide hybrid perovskite single crystals prepared are unified, which is beneficial to large-scale integration and array preparation.

[0039] The present application introduces a thermal slow-release layer on the perovskite single crystal pressed sheet, so that the electrode and the functional layer (i.e. the perovskite single crystal pressed sheet) of the memristor are directly contacted by van der Waals force. During the evaporation of the electrode, the bombardment damage of high-energy particles to the surface of the halide hybrid perovskite functional layer (i.e. the perovskite single crystal pressed sheet) can be effectively prevented, and vacancies, interstitial atoms and other lattice defects in the surface and near-surface regions of the functional layer can be avoided, thereby reducing the energy consumption of the memristor.

[0040] In addition, the preparation method of the van der Waals contact perovskite single crystal pressed sheet memristor of the present application connects the electrode and the functional layer (i.e. the perovskite single crystal pressed sheet) of the memristor by a low-defect contact method, so that the resistance change process of the memristor occurs in the functional layer, and the resistance change mechanism analysis of the memristor is not affected by the defects at the interface of the electrode and the functional layer.

[0041] The van der Waals contact perovskite single crystal pressed memristor prepared by the present invention has continuously variable memristive performance and low energy consumption characteristics, and can simulate biological synaptic plasticity. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 Schematic diagram of the process for preparing a perovskite single crystal pressed memristor with van der Waals contact according to Example 1.

[0043] Figure 2 This is the X-ray diffraction (XRD) pattern of the perovskite bulk single crystal of Example 1.

[0044] Figure 3 This is the X-ray diffraction (XRD) pattern of the perovskite bulk single crystal of Example 2.

[0045] Figure 4 This is a physical picture of the perovskite single crystal pressed sheet of Example 3.

[0046] Figure 5 This is an optical microscope image of the perovskite single crystal pressed memristor before removing the thermal release layer in Example 3.

[0047] Figure 6 This is an optical microscope image of the van der Waals contact perovskite single crystal pressed memristor after removing the thermal release layer in Example 3.

[0048] Figure 7 This is a physical picture of the perovskite single crystal pressed sheet of Example 4.

[0049] Figure 8 This is an optical microscope image of the perovskite single crystal pressed memristor before removing the thermal release layer in Example 4.

[0050] Figure 9 This is an optical microscope image of the van der Waals contact perovskite single crystal pressed memristor after removing the thermal release layer in Example 4.

[0051] Figure 10 This is a graph showing the resistive switching characteristic curve (IV) of the van der Waals contact perovskite single crystal pressed memristor of Example 3.

[0052] Figure 11 This is a graph showing the resistive switching characteristic curve (IV) of the van der Waals contact perovskite single crystal pressed memristor of Example 4.

[0053] Figure 12 This is a double pulse facilitation (PPF) diagram of the van der Waals contact perovskite single crystal compact memristor in Example 5.

[0054] Figure 13 This is a graph of the excitatory postsynaptic current (EPSC) of the van der Waals contacted perovskite single crystal pressed memristor of Example 3.

[0055] Figure 14 Excitatory post-synaptic current (EPSC) plot of the van der Waals contacted perovskite single crystal wafered memristor of Example 4.

[0056] Figure 15 Excitatory post-synaptic current (EPSC) plot of the perovskite single crystal wafered memristor of Comparative Example 1.

[0057] Figure 16 Excitatory post-synaptic current (EPSC) plot of the perovskite single crystal wafered memristor of Comparative Example 2. DETAILED DESCRIPTION

[0058] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be further described below in conjunction with specific examples.

[0059] In the embodiments and comparative examples of the present application, the use of reagents is as follows:

[0060] Polypropylene carbonate, manufacturer Sigma-Aldrich, item number 389021-25G.

[0061] Example 1

[0062] The present embodiment provides a van der Waals contacted perovskite single crystal wafered memristor, as shown in Figure 1 The preparation method thereof comprises the following steps:

[0063] S1. 4.8 mmol of CsBr and 9.6 mmol of PbBr2 were dissolved in 5.3 ml of DMSO to prepare a perovskite precursor solution of CsPbBr3, which was stirred using a magnetic stirrer for 8 h, then filtered using a 0.2 μm PTFE filter, and then the temperature of the perovskite precursor solution of CsPbBr3 was raised, and a seed crystal was precipitated at 80℃ for 2 h. The seed crystal was taken out and placed in a new perovskite precursor solution to continue growing at 85℃ for 36 h to obtain a perovskite bulk single crystal, and the XRD thereof is shown in Figure 2

[0064] S2. The perovskite bulk single crystal was ground into powder, 200 g of which was added to a circular mold with a diameter of 0.5 cm, and a wafering machine was used to wafer at 25℃, 15 Pa pressure, for 20 min to obtain a circular perovskite single crystal wafer with a diameter of 0.5 cm;

[0065] S3. A 1wt.% polypropylene carbonate (PPC) solution was prepared using anisole as the solvent, and the PPC was fully dissolved by magnetic stirring overnight, which was used as a thermal release material. A spin coater was used to spin coat the thermal release material on the perovskite single crystal wafer at a speed of 3000 rpm for 30 s, and then a thermal treatment was performed at 100℃ for 5 min to obtain a thermal release layer.​

[0066] S4. Adopting vacuum evaporation equipment, first use mechanical pump to extract the cavity to 1 x 10 -1 Pa, then use molecular pump to continue to extract to 2 x 10 -4 Pa, then evaporate metal Au on the thermal release layer as electrode, then use thermal decomposition method to treat 20 min at 250 DEG C to remove the thermal release layer, at this time, there is no chemical bond between the perovskite single crystal wafer and the electrode, namely, the perovskite single crystal wafer of van der Waals contact is obtained.

[0067] The thickness of the electrode is 100 nm.

[0068] Embodiment 2

[0069] The embodiment provides a perovskite single crystal wafer of van der Waals contact, and a preparation method thereof comprises the following steps:

[0070] S1. 2 mmol of PbBr2 and 2 mmol of MABr (methylamine hydrobromide) are dissolved in 2 ml of DMF to prepare a perovskite precursor solution of MAPbBr3, the solution is stirred by a magnetic stirrer for 8 h, then the perovskite precursor solution of MAPbBr3 is filtered by a 0.2 μm PTFE filter, then a seed crystal is precipitated at 85 DEG C for 2 h by using inverse temperature crystallization method, the seed crystal is taken out and placed in a new perovskite precursor solution to continue growing at 75 DEG C for 24 h, thereby a perovskite bulk single crystal is obtained, and XRD of the perovskite bulk single crystal is shown in FIG. 1. Figure 3

[0071] S2. The perovskite bulk single crystal is ground into powder, 350 g of the powder is added into a circular mold with a diameter of 2 cm, and a tablet machine is used to press the powder into a perovskite single crystal wafer with a diameter of 2 cm at 200 DEG C and a pressure of 25 Pa for 60 min.

[0072] S3. A 5wt. % polypropylene carbonate (PPC) solution is prepared by using anisole as a solvent, and the solution is stirred by a magnetic stirrer for one night so that the PPC is fully dissolved, and the solution is used as a thermal release material; the thermal release material is spin-coated on the perovskite single crystal wafer by using a spin coater at a rotating speed of 3000 rpm for 30 s, and then the wafer is treated at 100 DEG C for 5 min, thereby a thermal release layer is obtained.

[0073] S4. Adopting vacuum evaporation equipment, first use mechanical pump to extract the cavity to 1 x 10 -1 Pa, then use molecular pump to continue to extract to 2 x 10 -4 Pa, then evaporate metal Au on the thermal release layer as electrode, then use thermal decomposition method to treat 20 min at 250 DEG C to remove the thermal release layer, at this time, there is no chemical bond between the perovskite single crystal wafer and the electrode, namely, the perovskite single crystal wafer of van der Waals contact is obtained.​

[0074] The thickness of the electrode is 100 nm.

[0075] Example 3

[0076] This embodiment provides a van der Waals contact perovskite single crystal pressed memristor, the preparation method of which includes the following steps:

[0077] S1. A CsPbBr3 perovskite precursor solution was prepared by dissolving 4.8 mmol CsBr and 9.6 mmol PbBr2 in 5.3 ml DMSO. The solution was stirred using a magnetic stirrer for 8 hours, then filtered through a 0.2 μm PTFE filter. The temperature of the CsPbBr3 perovskite precursor solution was then increased to allow seed crystals to precipitate at 80°C for 2 hours. The seed crystals were removed and placed in a new perovskite precursor solution for further growth at 85°C for 36 hours to obtain bulk perovskite single crystals.

[0078] S2. Grind the perovskite bulk single crystal into powder, take 300g and add it to a circular mold with a diameter of 1cm, and use a tablet press to press it at 100℃ and 10Pa pressure for 40min to obtain Figure 4 The circular perovskite single crystal pressed wafer with a diameter of 1 cm is shown;

[0079] S3. A 3 wt.% polypropylene carbonate (PPC) solution was prepared using anisole as a solvent and magnetically stirred overnight to fully dissolve the PPC, thereby serving as a thermal release material. The thermal release material was spin-coated on a perovskite single crystal pellet at 3000 rpm for 30 seconds using a spin coater, followed by heat treatment at 100°C for 5 minutes to form a thermal release layer.

[0080] S4. Using vacuum evaporation equipment, first use a mechanical pump to pump the cavity to 1×10 -1 Pa, and then use the molecular pump to continue pumping to 2×10 -4 Pa, and then evaporate metal Au as the electrode on the thermal slow-release layer to obtain Figure 5 As shown in FIG, the perovskite single crystal pressed memristor before removing the thermal release layer is treated by thermal decomposition at 280°C for 40 minutes to remove the thermal release layer. At this time, there is no chemical bond between the perovskite single crystal pressed memristor and the electrode, and the result is as shown in FIG. Figure 6 The proposed perovskite single crystal pressed-chip memristor with Fan Dehua contact;

[0081] The thickness of the electrode is 100 nm.

[0082] Example 4

[0083] This embodiment provides a van der Waals contact perovskite single crystal pressed memristor, the preparation method of which includes the following steps:

[0084] S1. Prepare a perovskite precursor solution of MAPbBr3 by dissolving 2 mmol of PbBr2 and 2 mmol of MABr (methylamine hydrobromide) in 2 ml of DMF, stirring with a magnetic stirrer for 8 h, filtering the perovskite precursor solution of MAPbBr3 with a 0.2 μm PTFE filter, and then using inverse temperature crystallization to precipitate seeds at 85℃ for 2 h, taking out the seeds and placing them in a new perovskite precursor solution to continue growing at 75℃ for 24 h to obtain a perovskite bulk single crystal;

[0085] S2. Grind the perovskite bulk single crystal into powder, take 300 g and put it into a 1 cm diameter circular mold, and use a tablet press to press at 100℃, 10 Pa pressure for 40 min to obtain a 1 cm diameter circular perovskite single crystal tablet as shown in Figure 7 ;

[0086] S3. Prepare a 3wt.% polypropylene carbonate (PPC) solution with anisole as the solvent, magnetically stir overnight to fully dissolve the PPC, and use it as a thermal release material; use a spin coater to spin coat the thermal release material on the perovskite single crystal tablet at 3000 rpm for 30 s, and then perform 100℃ heat treatment for 5 min to obtain a thermal release layer;

[0087] S4. Use a vacuum evaporation device, first use a mechanical pump to evacuate the cavity to 1×10 -1 Pa, then use a molecular pump to continue to evacuate to 2×10 -4 Pa, then evaporate metal Au on the thermal release layer as an electrode to obtain a perovskite single crystal tablet memristor before removing the thermal release layer as shown in Figure 8 , and then use thermal decomposition at 280℃ to remove the thermal release layer for 40 min, at which time there is no chemical bond between the perovskite single crystal tablet and the electrode, thereby obtaining a van der Waals contact perovskite single crystal tablet memristor as shown in Figure 9 ;

[0088] The thickness of the electrode is 100 nm.

[0089] Example 5

[0090] The embodiment provides a van der Waals contact perovskite single crystal tablet memristor, and a preparation method thereof includes the following steps:

[0091] S1. A perovskite precursor solution of CsPbBr3 was prepared by dissolving 4.8 mmol of CsBr and 9.6 mmol of PbBr2 in 5.3 ml of DMSO, stirring with a magnetic stirrer for 8 h, filtering the perovskite precursor solution of CsPbBr3 with a 0.2 μm PTFE filter, then increasing the temperature of the perovskite precursor solution of CsPbBr3, and precipitating seeds at 80 °C for 2 h, taking out the seeds and placing them in a new perovskite precursor solution to continue growing at 85 °C for 36 h to obtain a perovskite bulk single crystal;

[0092] S2. The perovskite bulk single crystal was ground into powder, 250 g of which was added to a 1 cm diameter circular mold, and a tablet press was used to press the tablet at 150 °C and 20 Pa pressure for 30 min to obtain a 1 cm diameter circular perovskite single crystal tablet;

[0093] S3. A 3 wt. % polypropylene carbonate (PPC) solution was prepared using anisole as the solvent, and the PPC was fully dissolved by magnetic stirring overnight, which was used as a thermal release material; a spin coater was used to spin coat the thermal release material on the perovskite single crystal tablet at a speed of 3000 rpm for 30 s, and then a 100 °C heat treatment was performed for 5 min to obtain a thermal release layer;

[0094] S4. A vacuum evaporation device was used, first a mechanical pump was used to pump the cavity to 1 x 10 -1 Pa, then a molecular pump was used to continue pumping to 2 x 10 -4 Pa, then Au was evaporated on the thermal release layer as an electrode, and then a thermal decomposition method was used at 300 °C for 30 min to remove the thermal release layer, at this time there was no chemical bond between the perovskite single crystal tablet and the electrode, and a van der Waals contact perovskite single crystal tablet memristor was obtained;

[0095] The thickness of the electrode is 100 nm.

[0096] Comparative Example 1

[0097] This comparative example provides a perovskite single crystal tablet memristor, which is different from Example 3 in that no thermal release material (3 wt. % polypropylene carbonate solution) is used, and the thermal release layer is not removed, and both are consistent with Example 3, and the preparation method is as follows:

[0098] S1. A perovskite precursor solution of CsPbBr3 was prepared by dissolving 4.8 mmol of CsBr and 9.6 mmol of PbBr2 in 5.3 ml of DMSO, stirring with a magnetic stirrer for 8 h, filtering the perovskite precursor solution of CsPbBr3 with a 0.2 pm PTFE filter, and then increasing the temperature of the perovskite precursor solution of CsPbBr3 to precipitate seeds at 80 °C for 2 h, taking out the seeds, and placing them in a new perovskite precursor solution to continue growing at 85 °C for 36 h to obtain a perovskite bulk single crystal;

[0099] S2. The perovskite bulk single crystal was ground into powder, 300 g of which was added to a 1 cm diameter circular mold, and a tablet press was used to press the tablet at 100 °C and a pressure of 10 Pa for 40 min to obtain a 1 cm diameter circular perovskite single crystal tablet;

[0100] S3. A vacuum evaporation device was used, first using a mechanical pump to evacuate the cavity to 1 x 10 -1 Pa, then using a molecular pump to continue to evacuate to 2 x 10 -4 Pa, and then evaporating metal Au on the 1 cm diameter circular perovskite single crystal tablet as an electrode to obtain a perovskite single crystal tablet memristor;

[0101] The thickness of the electrode was 100 nm.

[0102] Comparative Example 2

[0103] This comparative example provides a perovskite single crystal tablet memristor, which differs from Example 4 in that no thermal release material (3 wt.% polypropylene carbonate solution) is used, and the thermal release layer is not removed, and both are consistent with Example 4, and the preparation method is specifically as follows:

[0104] S1. A perovskite precursor solution of MAPbBr3 was prepared by dissolving 2 mmol of PbBr2 and 2 mmol of MABr (methylamine hydrobromide) in 2 ml of DMF, stirring with a magnetic stirrer for 8 h, filtering the perovskite precursor solution of MAPbBr3 with a 0.2 pm PTFE filter, and then using inverse temperature crystallization to increase the temperature of the perovskite precursor solution of MAPbBr3 to precipitate seeds at 85 °C for 2 h, taking out the seeds, and placing them in a new perovskite precursor solution to continue growing at 75 °C for 24 h to obtain a perovskite bulk single crystal;

[0105] S2. The perovskite bulk single crystal was ground into powder, 300 g of which was added to a 1 cm diameter circular mold, and a tablet press was used to press the tablet at 100 °C and a pressure of 10 Pa for 40 min to obtain a 1 cm diameter circular perovskite single crystal tablet;

[0106] S3. A vacuum evaporation device was used, first using a mechanical pump to evacuate the cavity to 1 x 10-1 Pa, and then continue to pump to 2x10 -4 Pa, and then evaporate metal Au on the perovskite single crystal wafer as an electrode to obtain a perovskite single crystal wafer memristor;

[0107] The thickness of the electrode is 100 nm.

[0108] Performance test

[0109] Figure 5 Optical microscope image of the perovskite single crystal wafer memristor before removing the thermal release layer for Example 3. Figure 6 Optical microscope image of the perovskite single crystal wafer memristor with van der Waals contact after removing the thermal release layer for Example 3. Figure 8 Optical microscope image of the perovskite single crystal wafer memristor before removing the thermal release layer for Example 4. Figure 9 Optical microscope image of the perovskite single crystal wafer memristor with van der Waals contact after removing the thermal release layer for Example 4. Figure 5-6 And Figure 8-9 It can be seen that the thermal release layer on the perovskite single crystal wafer can be removed by using the thermal decomposition method at 280℃ for 40min.

[0110] At room temperature and low vacuum (1x10 －1 Pa) conditions, the resistance change characteristic curve (I-V) of the perovskite single crystal wafer memristor with van der Waals contact for Examples 3 and 4 was measured by using the FS-Pro semiconductor analyzer.

[0111] Figure 10 Resistance change characteristic curve (I-V) of the perovskite single crystal wafer memristor with van der Waals contact for Example 3. Figure 11 Resistance change characteristic curve (I-V) of the perovskite single crystal wafer memristor with van der Waals contact for Example 4. Figure 10-11 It can be seen that the perovskite single crystal wafer memristor with van der Waals contact for Examples 3 and 4 produces a slowly changing hysteresis loop with the change of external voltage, which shows that the conductance of the perovskite single crystal wafer memristor with van der Waals contact can be variable, and can be used to simulate the change of biological synapse weight.

[0112] At room temperature and low vacuum (1x10 －1 Pa) conditions, the double pulse facilitation of the perovskite single crystal wafer memristor with van der Waals contact for Example 5 was measured by using the FS-Pro semiconductor analyzer, wherein the PPF index was obtained by applying a pair of pulse stimuli and the formula PPF=A2 / A1x100%, A2 was the excitatory postsynaptic current generated by the second pulse, A1 was the excitatory postsynaptic current generated by the second pulse, and △T was the time interval between the pair of pulses.

[0113] Figure 12 Figure of double-pulse facilitation (PPF) of the van der Waals-contacted perovskite single-crystal pressel memory of Example 5. The PPF index of the van der Waals-contacted perovskite single-crystal pressel memory of Example 5 was calculated according to the following formula: PPF index = (I1-I0) / (I2-I0), wherein I0 is the baseline current, I1 is the current after the first pulse, and I2 is the current after the second pulse. Figure 12 It can be seen that the PPF index of the van der Waals-contacted perovskite single-crystal pressel memory of Example 5 increases as the paired pulse time interval decreases, which indicates that the synaptic plasticity of the van der Waals-contacted perovskite single-crystal pressel memory of the present application can be adjusted by the frequency of the applied pulses.

[0114] At room temperature and under low vacuum (1x10 －1 Pa) conditions, the excitatory postsynaptic current (EPSC) of the van der Waals-contacted perovskite single-crystal pressel memory of Example 3-4 and the perovskite single-crystal pressel memory of Comparative Example 1-2 was measured using a FS-Pro semiconductor analyzer.

[0115] Figure 13 Figure of excitatory postsynaptic current (EPSC) of the van der Waals-contacted perovskite single-crystal pressel memory of Example 3. Figure 14 Figure of excitatory postsynaptic current (EPSC) of the van der Waals-contacted perovskite single-crystal pressel memory of Example 4. Figure 15 Figure of excitatory postsynaptic current (EPSC) of the perovskite single-crystal pressel memory of Comparative Example 1. Figure 16 Figure of excitatory postsynaptic current (EPSC) of the perovskite single-crystal pressel memory of Comparative Example 2. From Figure 13-16 It can be seen that, after the electrical pulses are removed, the van der Waals-contacted perovskite single-crystal pressel memories of Example 3-4 and the perovskite single-crystal pressel memories of Comparative Example 1-2 all exhibit a phenomenon of current decay over time. According to the formula for calculating energy consumption: E = VIT, wherein E is the energy consumption, unit J, V is the read voltage, unit V, I is the excitatory postsynaptic current, unit A, and T is the duration of the pulse, unit s, the energy consumption values of the van der Waals-contacted perovskite single-crystal pressel memories of Example 3-4 and the perovskite single-crystal pressel memories of Comparative Example 1-2 can be calculated, which are shown in Table 1, and thus it can be seen that the van der Waals-contacted perovskite single-crystal pressel memories prepared by the preparation method of the present application have the advantage of low energy consumption.

[0116] Table 1 Energy consumption values of the perovskite single-crystal pressel memories of Example 3-4 and Comparative Example 1-2

[0117] Example 3 Example 4 Comparative Example 1 Comparative Example 2 V (V) -0.0001 -0.0001 -0.0001 -0.0001 I (A) -0.03 x 10 -9 ]] -0.028 x 10 -9 ]] -0.19 x 10 -9 ]]> -0.1 x 10 -9 ]] T (s) 0.01 0.01 0.01 0.01 E (J) 0.030 x 10 -15 ]] 0.028 x 10 -15 ]] 0.190 x 10 -15 ]] 0.100 x 10 -15 ]]

[0118] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application and are not intended to limit the scope of protection of the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present application.

Claims

1. A method for preparing a van der Waals contact perovskite single crystal pressed memristor, characterized in that: The steps include: S1. Prepare perovskite bulk single crystals by inversion crystallization using a perovskite precursor solution; S2. Grinding the perovskite bulk single crystal and pressing it into a perovskite single crystal pressed sheet; S3. Preparing a thermal release layer on the perovskite single crystal pressed sheet using a thermal release material; S4. Evaporating an electrode on the thermal release layer, and then removing the thermal release layer by thermal decomposition, thereby obtaining a perovskite single crystal compact memristor with van der Waals contact; The thermal sustained-release material is a polypropylene carbonate solution with a mass percentage of 1wt.%-5wt.%.

2. The method for preparing a van der Waals contact perovskite single crystal pressed memristor according to claim 1, characterized in that: The perovskite is at least one of CsPbBr3, CsPbI3, MAPbBr3, and MAPbI3.

3. The method for preparing a van der Waals contact perovskite single crystal pressed memristor according to claim 1, wherein: In step S1, the inversion crystallization method refers to first increasing the temperature of the perovskite precursor solution to precipitate seed crystals, taking out the seed crystals, and placing them into a new perovskite precursor solution to continue growing to obtain a perovskite bulk single crystal.

4. The method for preparing a van der Waals contact perovskite single crystal pressed memristor according to claim 3, characterized in that: The temperature for precipitating the seed crystals is 80-85° C., and the time is 0.5-2 hours.

5. The method for preparing a van der Waals contact perovskite single crystal pressed memristor according to claim 3, characterized in that: The temperature for the continued growth is 75-85° C., and the time is 24-48 hours.

6. The method for preparing a van der Waals contact perovskite single crystal pressed memristor according to claim 1, characterized in that: In step S2, the tableting pressure is 10-25 Pa, the temperature is 25-200° C., and the time is 20-60 min.

7. The method for preparing a van der Waals contact perovskite single crystal pressed memristor according to claim 1, characterized in that: The step S3 specifically comprises: spin coating a thermal slow-release material on the perovskite single crystal pressed sheet, and then performing a heat treatment to obtain a thermal slow-release layer.

8. The method for preparing a van der Waals contact perovskite single crystal pressed memristor according to claim 7, characterized in that: The spin coating has a rotation speed of 2000-3500 rpm and a time of 20-30 s.

9. The method for preparing a van der Waals contact perovskite single crystal pressed memristor according to claim 7, characterized in that: The heat treatment temperature is 90-100° C. and the time is 5-15 minutes.

10. A van der Waals contact perovskite single crystal pressed memristor, characterized in that: The invention is prepared by the preparation method according to any one of claims 1 to 9.

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