Preparation method of perovskite memristor with high on-off ratio

Abstract

The invention relates to the technical field of memristors, in particular to a preparation method of a perovskite memristor with a high switching ratio, and aims to solve the problems of poor repeatability and insufficient reliability of devices prepared by a traditional oxidation method in the technical field of constructing a memristor functional layer based on an MXene material, a Ti3C2Tx / FA0. 1MA0. 9PbI3-BAI composite film is adopted as a functional layer, and a perovskite memristor with a high switching ratio is prepared. Specifically, a heterojunction is constructed by Ti3C2Tx and perovskite, and an MXene interlayer metal conductive channel is inhibited by using the semiconductor characteristics of perovskite, so that the switch ratio is improved; by combining BAI surface modification, a passivation layer is formed on the surface of the perovskite, surface defects are inhibited, a BAI hydrophobic long chain constructs a physical barrier layer, and the chemical stability and environmental stability of the device are improved. The experimental method disclosed by the invention has the characteristic of simplicity and convenience in operation, and is beneficial to solving the problems confronted by constructing the memristor function layer by the current oxidation method.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of memristor, and particularly relates to a preparation method of a high-switching-ratio perovskite memristor. BACKGROUND

[0002] As a new type of electronic device that realizes information storage and computing fusion through resistance state change, the memristor has become a core technology path for developing the next generation of nonvolatile memory and neuromorphic computing chips due to its core advantages of high-density integration, low-power operation and brain-like synaptic plasticity. Under this background, the deep integration of material science and nanotechnology has led to research breakthroughs in the composite system of MXene materials and perovskite semiconductors, and the collaborative interface design of MXene materials and perovskite is particularly eye-catching. Through the interface composite of MXene conductive materials and ion migration semiconductors, not only can the performance bottleneck of traditional memristor devices be broken through, but also significant potential can be shown in the aspects of switching ratio improvement, environmental stability enhancement and bionic function optimization, becoming one of the most promising technical routes in the field of resistive devices.

[0003] Ti3C2T x As a two-dimensional material in the MXene family that has realized large-scale preparation first, since the Gogotsi team pioneered the hydrofluoric acid etching method to obtain it from the Ti3AlC2 precursor, its unique layered crystal structure, tunable surface chemical properties and outstanding charge transport capacity make it have important application value in the field of flexible electronic devices. The material has high intrinsic conductivity, controllable surface terminal groups and good mechanical flexibility, and is particularly suitable for building high-performance optoelectronic devices. However, the following technical bottlenecks exist when Ti3C2T x is directly applied to a memristor device: firstly, the inherent high conductivity of the material makes it difficult to achieve effective high-resistance state isolation during the resistance change process, and the existence of interlayer metallic conduction channels significantly reduces the high-low resistance state discrimination; secondly, although the spontaneous oxidation behavior of the material surface under environmental exposure conditions can form a resistance change dielectric layer, the uneven spatial distribution of the oxidation products leads to uncontrollable drift of the device switching characteristics; thirdly, the chemical stability of the MXene material under conventional working conditions is insufficient, and its surface functional groups and layered structure are easily affected by environmental factors to degrade, which directly causes the degradation of the cycle stability and batch repeatability of the device. These inherent defects at the material level seriously restrict the reliability performance of the memristor device based on Ti3C2T x in actual application. SUMMARY

[0004] The application aims to provide a preparation method of a high-switching-ratio perovskite memristor.

[0005] To achieve the above-mentioned purpose, the application provides a preparation method of a high-switching-ratio perovskite memristor, comprising the following steps:

[0006] Step 1: ITO is used as a substrate, and ultrasonic cleaning treatment is performed;

[0007] Step 2: the sample after the drying treatment in step 1 is subjected to hydrophilic treatment;

[0008] Step 3: Ti3C2Tx solution with a concentration of 8 mg / ml is spin-coated on the surface of the sample after the treatment in step 2; x solution;

[0009] Step 4: PbI2, MAI and FAI powders are taken, and the molar ratio of PbI2: MAI: FAI is (9.5-10.6):(8.6-9.5):(0.9-1.1), which are dissolved in a DMF and DMSO mixed solvent to prepare a FA 0.1 MA 0.9 PbI3 perovskite precursor solution, and fully stirred at a speed of 700-800 r / min for 6 hours; BAI powder is dissolved in an IPA solution to prepare a BAI solution with a concentration of 1 mg / ml-6 mg / ml, and fully stirred at a speed of 700-800 r / min for 2 hours;

[0010] Step 5: the perovskite precursor solution is spin-coated on the surface of the sample obtained in step 3 at a speed of 3000 r / min-7000 r / min for 35 s;

[0011] Step 6: the sample obtained in step 5 is subjected to annealing treatment at 100℃ for 5 min-10 min on a heating platform;

[0012] Step 7: BAI solution is spin-coated on the surface of the sample obtained in step 6, and annealing treatment is performed at 100℃ for 5-10 min on a heating platform;

[0013] Step 8: a top silver electrode is plated on the sample obtained in step 7 by using a thermal evaporation instrument, and in the thermal evaporation process, the evaporation rate is 0.1 A / s to plate to a thickness of 0.10±0.01 nm, and then the evaporation rate is 1 A / s to plate to a thickness of 150 nm-200 nm.

[0014] Optionally, in the process of step 1 ultrasonic cleaning treatment, the ITO substrate is sequentially subjected to ultrasonic treatment in ITO cleaning solution, 99% concentration anhydrous ethanol and deionized water.

[0015] Optionally, in step 2, the hydrophilic treatment is performed by using a plasma cleaning machine.

[0016] Optionally, in the process of step 3 spin coating, the sample is placed on a spin coater to spin coat Ti3C2T x solution at a low speed of 500 r / min for 5 s and a high speed of 1000 r / min for 60 s.

[0017] Optionally, in step 4, the volume ratio of the mixed solvent of DMF and DMSO is DMF: DMSO = 9:1.

[0018] Optionally, in the process of step 5 spin coating, the anti-solvent toluene needs to be added at the 5th second.

[0019] Optionally, steps 4 to 7 are all performed in a nitrogen glove box environment.

[0020] The application provides a preparation method of a high-switching-ratio perovskite memristor, and belongs to the technical field of constructing a memristor functional layer based on MXene material. x / FA 0.1 MA 0.9 PbI3-BAI composite film as a functional layer, specifically by constructing a heterojunction of Ti3C2T x and perovskite, using the perovskite semiconductor characteristics to inhibit the metal conductive channel between the MXene layers, so as to improve the switching ratio; in combination with the surface modification of BAI, a passivation layer is formed on the perovskite surface to inhibit surface defects, and a physical barrier layer is constructed by the BAI hydrophobic long chain to improve the chemical stability and environmental stability of the device. The experimental method has the characteristics of simple operation, and helps to improve the problems faced by the current oxidation method for constructing a memristor functional layer. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor.

[0022] Figure 1 is a preparation process schematic diagram of a specific embodiment of the preparation method of the high-switching-ratio perovskite memristor of the application.

[0023] Figure 2 ITO / Ti3C2T x / FA 0.1 MA 0.9 PbI3-BAI / Ag memristor array structure schematic diagram.

[0024] Figure 3 ITO / Ti3C2T x / FA 0.1 MA 0.9 PbI3-BAI / Ag I-V curve schematic diagram.

[0025] Figure 4 Ti3C2T x / FA 0.1 MA 0.9 PbI3 thin film surface SEM image schematic diagram.

[0026] Figure 5 Ti3C2T x / FA 0.1 MA 0.9 PbI3-BAI thin film surface SEM image schematic diagram. DETAILED DESCRIPTION

[0027] Embodiments of the present application are described in detail below with reference to the attached drawing figures, wherein the same or like reference numerals and characters throughout the figures denote the same or like components or elements having the same or similar functions. The embodiments described below are exemplary and are intended to be illustrative of the present application and are not to be construed as limiting thereof.

[0028] The following are some of the abbreviations in the present application:

[0029] PbI2: lead iodide;

[0030] MAI: methylammonium iodide, CH3NH3PbI3;

[0031] FAI: formamidinium hydroiodide, HC(NH2)2;

[0032] BAI: butylammonium iodide, C4H 12 IN

[0033] DMF: dimethylformamide, N,N-Dimethylformamidex;

[0034] DMSO: dimethyl sulfoxide.

[0035] The application provides a preparation method of a high-switching-ratio perovskite memristor, comprising the following steps:

[0036] Step 1: Step 1: ITO is used as a substrate, and ultrasonic cleaning treatment is performed;

[0037] Step 2: the sample after the drying treatment in step 1 is subjected to hydrophilic treatment;

[0038] Step 3: Ti3C2T x solution with a concentration of 8 mg / ml is spin-coated on the surface of the sample after the treatment in step 2;

[0039] Step 4: PbI2, MAI and FAI powders are taken, PbI2: MAI: FAI = (9.5~10.6) : (8.6~9.5) :(0.9~1.1) in molar ratio are dissolved in a DMF and DMSO mixed solvent to prepare a FA 0.1 MA 0.9 PbI3 perovskite precursor solution, and the solution is fully stirred at a rotation speed of 700-800 r / min for 6 hours; BAI powder is further taken and dissolved in an IPA solution to prepare a BAI solution with a concentration of 1 mg / ml-6 mg / ml, and the solution is fully stirred at a rotation speed of 700-800 r / min for 2 hours;

[0040] Step 5: the perovskite precursor solution is spin-coated on the surface of the sample obtained in step 3 at a parameter of 3000 r / min-7000 r / min and 35 s;

[0041] Step 6: the sample obtained in step 5 is subjected to annealing treatment at 100 DEG C for 5 min-10 min on a heating platform;

[0042] Step 7: the BAI solution is spin-coated on the surface of the sample obtained in step 6, and the sample is subjected to annealing treatment at 100 DEG C for 5-10 min on a heating platform;

[0043] Step 8: a top silver electrode is plated on the sample obtained in step 7 by using a thermal evaporation instrument, and in the thermal evaporation process, the evaporation rate is 0.1 A / s to plate to a thickness of 0.10+ / -0.01 nm, and then the evaporation rate is 1 A / s to plate to a thickness of 150 nm-200 nm.

[0044] In the technical field of constructing a memristor functional layer based on MXene material, the devices prepared by the traditional oxidation method generally face the bottleneck of poor repeatability and insufficient reliability. The application innovatively proposes a solution of using Ti3C2T x / FA 0.1 MA 0.9 PbI3-BAI composite film as a functional layer: by using Ti3C2T xThe perovskite is used to construct a heterojunction, the metal conductive channel between the MXene layers is inhibited by using the perovskite semiconductor characteristics, so that the on-off ratio is improved; the BAI surface modification is combined, a passivation layer is formed on the perovskite surface to inhibit the surface defects, and the BAI hydrophobic long chain constructs a physical barrier layer, so that the chemical stability and environmental stability of the device are improved.

[0045] The following is further described in combination with the specific embodiment manufacturing process:

[0046] Please refer to Figures 1 to 5 , the ITO / Ti3C2T x / FA 0.1 MA 0.9 PbI3-BAI / Ag memristor in the embodiment has a lower working voltage, and Ti3C2T x does not need to be oxidized, and the device preparation repetition rate is high.

[0047] The execution process of the embodiment is as follows:

[0048] S1: Prepare ITO with a size of 18*18mm 2 as a substrate, and ultrasonically clean the ITO in ITO cleaning solution, anhydrous ethanol (concentration of 99%) and deionized water for 20min.

[0049] S2: After drying the sample obtained in step S1, perform hydrophilic treatment in a plasma cleaning machine.

[0050] S3: Spin-coat the Ti3C2Tx solution with a concentration of 8mg / ml on the sample obtained in step S2 on a spin coater at a low speed of 500r / min for 5s and a high speed of 1000r / min for 60s.

[0051] S4: Take lead iodide (PbI2) 599.30mg, methylammonium iodide (CH3NH3PbI3, MAI) 186.03mg, formamidine hydroiodide (HC(NH2)2, FAI) 22.36mg, dimethylformamide (N,N-Dimethylformamidex, DMF) 0.9ml and dimethyl sulfoxide (Dimethyl sulfoxide, DMSO) 0.1ml, prepare FA 0.1 MA 0.9 PbI3 perovskite precursor solution in a nitrogen glove box, and fully stir at a speed of 800r / min for 6 hours; take BAI powder and dissolve it in IPA solution to prepare a BAI solution with a concentration of 1mg / ml, and fully stir at a speed of 800r / min for 2h.

[0052] S5: spin-coat the perovskite precursor solution on the sample obtained in S3 on a spin coater at a speed of 5000 r / min for 35 s, and drop the anti-solvent toluene at the 5th second.

[0053] S6: anneal the sample obtained in S5 at 100℃ for 5 min on a heating platform to construct Ti3C2T x / FA 0.1 MA 0.9 PbI3 composite film.

[0054] S7: after the sample obtained in S6 is cooled to room temperature, spin-coat the BAI solution on the sample obtained in S6 on a spin coater at a speed of 3000 r / min for 30 s.

[0055] S8: anneal the sample obtained in S7 at 100℃ for 10 min to promote the passivation of BAI on the perovskite surface and form a stable interface modification layer.

[0056] S9: cover the sample obtained in S8 with a mask plate of a specific specification, and plate the top Ag electrode by a thermal evaporation method, wherein, in the thermal evaporation process, first, the evaporation rate is 0.1 A / s, and the thickness is 0.10±0.01 nm, and then the evaporation rate is 1 A / s, and the thickness is 150 nm-200 nm.

[0057] Specifically, Figure 1 is a schematic diagram of the experimental operation process of the ITO substrate of the present application, including cleaning, spin-coating, annealing and plating of the top electrode.

[0058] Figure 2 is a schematic diagram of the sample structure of the present application, wherein the bottom substrate is glass, and the ITO electrode, Ti3C2T x / layer, FA 0.1 MA 0.9 PbI3 layer, BAI layer and silver electrode are sequentially arranged on the glass.

[0059] Figure 3 is an I-V curve diagram of the sample of the present application tested under a voltage of 4V→-4V, and the "On / Off Ratio>10 6 " is read at a voltage of -0.1V.

[0060] Figure 4 and Figure 5 are respectively Ti3C2T x / FA 0.1 MA 0.9 PbI3 and Ti3C2T x / FA 0.1 MA 0.9The schematic diagram of the SEM image of the surface of the PbI3-BAI thin film, the scale is 300nm, and it can be found that BAI has an effect on FA 0.1 MA 0.9 The surface of the PbI3 thin film is modified and passivated.

[0061] Compared with the prior art, the application has the beneficial effects that:

[0062] The application utilizes a solution deposition method to prepare a Ti3C2Tx / FA0.1MA0.9PbI3-BAI composite thin film as an active layer of a memristor, and the experimental method has the characteristics of simple operation, which helps to improve the problems faced by the current oxidation method for constructing a functional layer of a memristor, and has a positive effect on improving the repetition rate of the preparation of the memristor and enhancing the reliability of the device. The scheme provides certain theoretical reference and practical reference for the development of the memristor technology, has reference value for promoting the application and related research in the field of the memristor, and is expected to provide a new idea for subsequent research and technical optimization of the memristor.

[0063] The above only discloses one or more preferred embodiments of the application, and of course cannot limit the scope of the right of the application, and those skilled in the art can understand that all or part of the processes of the above embodiments are implemented, and equivalent changes made according to the claims of the application still belong to the scope covered by the application.

Claims

1. A method for preparing a high switching ratio perovskite memristor, characterized in that: The following steps are involved: Step 1: Using ITO as the substrate, perform ultrasonic cleaning; Step 2: Perform hydrophilic treatment on the sample after drying in step 1; Step 3: Spin-coat the surface of the sample treated in step 2 with a concentration of 8 mg / ml Ti3C2T x solution; Step 4: Take PbI2, MAI and FAI powders and dissolve them in a mixed solvent of DMF and DMSO at a molar ratio of PbI2: MAI: FAI = (9.5~10.6): (8.6~9.5): (0.9~1.1) to prepare FAI. 0.1 MA 0.9 PbI3 perovskite precursor solution was prepared and stirred at a speed of 700-800 r / min for 6 hours. BAI powder was dissolved in IPA solution to prepare a BAI solution with a concentration of 1 mg / ml-6 mg / ml, and stirred at a speed of 700-800 r / min for 2 hours. Step 5: Spin-coat the perovskite precursor solution on the surface of the sample obtained in step 3 at a speed of 3000 rpm to 7000 rpm for 35 seconds. Step 6: Anneal the sample obtained in step 5 on a heating platform at 100°C for 5-10 minutes; Step 7: Spin-coat the BAI solution on the surface of the sample obtained in step 6 and perform annealing treatment on a heating platform at 100°C for 5-10 minutes; Step 8: The sample obtained in step 7 is plated with a top silver electrode using a thermal evaporation apparatus. During the thermal evaporation process, the sample is first plated at an evaporation rate of 0.1 A / s to a thickness of 0.10±0.01 nm, and then plated at an evaporation rate of 1 A / s to a thickness of 150 nm-200 nm.

2. The method for preparing a high switching ratio perovskite memristor according to claim 1, wherein: During the ultrasonic cleaning process in step 1, the ITO substrate is ultrasonically treated in an ITO cleaning solution, anhydrous ethanol with a concentration of 99%, and deionized water in sequence.

3. The method for preparing a high switching ratio perovskite memristor according to claim 2, wherein: In step 2, a plasma cleaning machine is used for hydrophilic treatment.

4. The method for preparing a high switching ratio perovskite memristor according to claim 3, wherein: During the spin coating process in step 3, the sample was placed on a spin coater and spin coated with Ti3C2T at a low speed of 500 r / min for 5 s and a high speed of 1000 r / min for 60 s. x solution.

5. The method for preparing a high switching ratio perovskite memristor according to claim 4, wherein: The volume ratio of the DMF and DMSO mixed solvent in step 4 is DMF:DMSO=9:

1.

6. The method for preparing a high switching ratio perovskite memristor according to claim 5, wherein: During the spin coating process in step 5, the anti-solvent toluene needs to be added dropwise at the 5th second.

7. The method for preparing a high switching ratio perovskite memristor according to claim 6, wherein: Steps 4 to 7 were all carried out in a nitrogen glove box environment.

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