Perovskite nanowire based on MOF mesoporous channel arrangement and preparation method

Abstract

This invention discloses perovskite (ABX3) nanowires based on MOF mesoporous channel arrangement and their preparation method. The method is based on the preparation of a perovskite nanowire / MOF composite material, comprising a mesoporous MOF and perovskite nanowires grown within its channels. The preparation method involves first synthesizing mesoporous MOF crystals, then repeatedly filtering and rinsing the synthesized MOF crystals with a vacuum-degassed octadecene solution to disperse them into an octadecene solution containing the MOF crystals. Next, a two-step growth method is used to progressively load perovskite metal cations and halide anions into the MOF crystal channels. Under heating conditions, the perovskite component ions in the channels nucleate and grow along the MOF channel direction to form perovskite nanowires, creating a nanowire array within the ordered MOF mesoporous channels. This preparation method is simple, uses mild conditions, can utilize the MOF mesoporous channels to arrange perovskite nanowires into an array, and yields a composite material with higher stability.

Description

Technical Field

[0001] This invention discloses a perovskite nanowire based on MOF mesoporous channel arrangement and its preparation method, which relates to the field of perovskite and metal-organic framework materials technology. Background Technology

[0002] Metal halide perovskite nanomaterials (such as lead methylene ammonium bromide (CH3NH3PbBr3) and lead cesium bromide (CsPbBr3)) possess excellent photoelectronic properties, including long and balanced carrier diffusion lengths and wide spectral absorption ranges. Therefore, perovskite materials are not only used to fabricate efficient and clean solar cells but are also widely applied in high-gain photodetectors. By using different synthesis methods, metal halide perovskite nanomaterials with varying sizes, morphologies, and optical properties can be obtained. Among them, single-crystal perovskite nanowires, as one-dimensional semiconductor materials, possess advantages such as structural anisotropy, low grain boundary density, and excellent mechanical properties, showing great potential in applications such as polarized light detection, flexible optoelectronic devices, and highly flexible photodetectors. However, the disordered arrangement and small light-receiving area of ​​single-crystal perovskite nanowires result in less than ideal photoelectric conversion efficiency.

[0003] Currently, most methods for realizing perovskite nanowire arrays involve growing them on specific substrates. This has the advantage of reducing or even eliminating the nanowire alignment process necessary for subsequent device fabrication, while also allowing control over the nanowire array density. However, perovskite nanowires grown in this way exhibit poor hydrothermal stability and a high number of surface defect states, thus affecting their optoelectronic properties. Summary of the Invention

[0004] To address the deficiencies in the aforementioned background technology, this invention provides a perovskite nanowire based on MOF mesoporous channel arrangement and its preparation method, thereby improving the stability and photoelectric conversion efficiency of perovskite nanowires.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a perovskite nanowire based on MOF mesoporous channel arrangement, comprising: perovskite nanowires and MOF crystal, wherein the perovskite nanowires are arranged in an array, namely ABX3, within the mesoporous channels of the MOF crystal. Crystalline composite material, wherein A represents organic cation CH3NH3 + or inorganic cation Cs + B represents a divalent metal cation, and X represents a halide anion.

[0006] A method for preparing perovskite nanowires based on MOF mesoporous channel arrangement includes the following steps:

[0007] Step 1: Add mesoporous MOF crystals to the first precursor solution BX2, which is a metal halide, and heat the solution. Under heating conditions, BX2 decomposes into divalent metal cations B. 2+ and halogen anion X - Under the adsorption of metal sites in MOF crystals and driven by thermal kinetic energy, divalent metal cations B... 2+ and halogen anion X - Entering the mesoporous channels of the MOF crystal;

[0008] Step 2: Load the divalent metal cation B from Step 1 2+ and halogen anion X - The first precursor solution of MOF crystals is added with a coordinating cation A + In the second precursor solution, the mixed solution is heated for a period of time. Under the heating conditions, the coordinating cation A in the mixed solution... + It enters the mesoporous channels of the MOF crystal and reacts with the divalent metal cation B. 2+ and halogen anion X - The reaction produces ABX3 crystal nuclei, which, driven by thermal kinetic energy and constrained by the steric hindrance of the MOF channels, grow along the mesopore direction of the MOF crystal, yielding a product containing ABX3. A mixed solution of crystalline composite materials was prepared to achieve the alignment of ABX3 nanowires.

[0009] Step 3: ABX3 is contained in Step 2. Methyl acetate is added to a mixed solution of crystalline composite materials to absorb impurities. After the reaction, solvents such as oleic acid, oleylamine, and octadecene in the solution are absorbed by methyl acetate. After settling and centrifugation, a precipitate is obtained. Settling is used to initially separate the supernatant containing waste solvent from the precipitate. The precipitate is ABX3. Crystalline composite materials.

[0010] Furthermore, the aforementioned divalent metal cation B 2+ Includes: Pb 2+ or Sn 2+ The halide anion X - Including: CI - ,Br - Or I - The first precursor solution comprises one of PbCl2, SnCl2, PbBr2, SnBr2, PbI2, and SnI2, wherein the coordinating cation A + Includes: CH3NH3 + or Cs + The second precursor solution includes one of CH3NH3Br or Cs2CO3.

[0011] Furthermore, in step 3, the settling time is 5 to 15 minutes, and the centrifugation time is 5 to 15 minutes at 4000 to 8000 rpm.

[0012] Furthermore, in step 3, the volume ratio of the added methyl acetate to the mixed solution is 1:4 to 1:6.

[0013] Furthermore, an accelerator is added to both the first precursor solution and the second precursor solution before heating. The accelerator includes oleic acid, oleylamine, and octadecene.

[0014] Furthermore, steps 1 and 2 are carried out in a nitrogen-filled environment, and the heating temperature is 100-120°C.

[0015] Furthermore, the preparation method of mesoporous MOF crystals described in step 1 specifically includes the following steps: mixing metal clusters, organic linking ligands, and surfactants as secondary structural units and adding them to a Teflon reaction vessel to form a MOF single crystal precursor solution, then subjecting it to ultrasonic dissolution, high-temperature heat treatment, cooling, filtration and washing, and activation.

[0016] Furthermore, the metal clusters include: Fe3O(OOCCH3)6OH]·2H2O or FeCI2·4H2O,

[0017] Organic linker ligands include: N2(2,5-DOT) or M-TCPPCl, wherein N includes: Zn 2+ Mg 2+ DOT stands for dioxidoterephthalate; M includes: Fe 3+ Mn 3+ ;

[0018] Surfactants include dimethylformamide (DMF), trifluoroacetic acid, or ethyl acetate.

[0019] Furthermore, the MOF single crystal precursor solution is subjected to ultrasonic dissolution, high-temperature heat treatment, cooling, filtration and washing, and activation. Specifically, the following steps are included: the precursor solution is ultrasonically dissolved at room temperature and ultrasonic frequency of 35-45 kHz for 8-12 minutes, then heat-treated at 110-130℃ for 10-15 hours. After the precursor solution is cooled to room temperature, it is washed. First, the MOF crystal is washed three times with DMF to remove unreacted ligands and metal clusters. Then, it is filtered and washed three times with octadecene solution to remove the surface of the MOF crystal and displace the solvent in the precursor solution in the pores of the MOF crystal. Next, it is pre-activated by soaking in acid solution for 4-8 hours, then rinsed twice with DMF, and finally activated under supercritical carbon dioxide.

[0020] Beneficial effects: This invention proposes to arrange ABX3 nanowires using mesoporous channels of MOF crystals to form an ABX3 nanowire array. A method for preparing crystalline composite materials, wherein the ABX3 nanowire array in the composite material prepared by this method has high order and orientation and is stable;

[0021] Arranging single-crystal perovskite nanowires to form a perovskite nanowire array provides better uniformity and repeatability compared to randomly distributed nanowires, thereby greatly improving the efficiency of nanodevices. Attached Figure Description

[0022] Figure 1 To prepare ABX3 A schematic diagram of crystalline composite materials;

[0023] Figure 2 Preparation of CsPbBr3 in this embodiment of the invention Flowchart of crystalline composite materials;

[0024] Figure 3 CH3NH3PbBr3 was prepared in the embodiments of the present invention. Flowchart of crystalline composite materials;

[0025] Figure 4 The image shown is a PXRD pattern of PCN-600 obtained through simulation in an embodiment of the present invention.

[0026] Figure 5 The image shows the PXRD pattern of CsPbBr3 obtained by simulation in this embodiment of the invention.

[0027] Figure 6 CsPbBr3 in the embodiments of the present invention PXRD pattern of crystalline composite material. Detailed Implementation

[0028] The implementation of the technical solution will be further described in detail below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0029] Implementation 1:

[0030] like Figure 1 One embodiment shown: a perovskite nanowire based on MOF mesoporous channel arrangement, comprising: perovskite nanowires and MOF crystal, wherein the perovskite nanowires are arranged in an array, namely ABX3, within the mesoporous channels of the MOF crystal. Crystalline composite material, wherein A represents organic cation CH3NH3 + or inorganic cation Cs+ B represents a divalent metal cation, and X represents a halide anion.

[0031] Implementation 2:

[0032] like Figure 2 As shown, in this embodiment, the MOF crystal used is PCN-600.

[0033] In this embodiment, a CsPbBr3 The preparation process of composite materials specifically includes the following steps:

[0034] Step 1: The preparation method of the mesoporous porous coordination network PCN-600 used in this embodiment is as follows:

[0035] (a): Dissolve 8 g of Fe(NO3)3·9H2O and 11 g of Na(OOCCH3)·3H2O in 9 mL of deionized water and stir magnetically at room temperature for 12 hours; centrifuge the resulting solution twice at 12000 rpm for 10 minutes each time, then remove the supernatant, transfer the precipitate to a vessel containing 10 mL of DMF and recrystallize at 150 °C to obtain Fe3O(OOCCH3)6OH]·2H2O;

[0036] (b): 20 mg Fe-TCPP, 20 mg [Fe3O(OOCCH3)6OH]·2H2O and 600 μL trifluoroacetic acid were added to a Teflon reactor containing 4 mL DMF to obtain a precursor solution;

[0037] (c): The precursor solution was ultrasonically dissolved for 10 minutes at room temperature and an ultrasonic frequency of 40 kHz, and then heat-treated in an oven at 120°C for 12 hours. After the precursor solution cooled to room temperature (approximately 20°C), the PCN-600 crystals were first washed three times with DMF, and then washed three times with octadecene solution. Next, the washed MOF crystals were rinsed three times with DMF, pre-activated by soaking in dilute hydrochloric acid solution for 6 hours, then rinsed twice with DMF, and finally activated under supercritical carbon dioxide to obtain PCN-600 crystals. The simulated X-ray diffraction (XRD) results are as follows: Figure 4 As shown.

[0038] Step 2: Add 0.5 g of the prepared PCN-600 single crystal to a precursor solution containing 0.138 g PbBr2, 0.5 mL oleic acid, 1 mL oleylamine, and 8 mL octadecene, and heat at 110 °C for 2 hours. Simultaneously, heat a precursor solution containing 0.03 g Cs2CO3, 0.5 mL oleic acid, and 7 mL octadecene at 110 °C for 2 hours.

[0039] Step 3: Heat the Pb-containing...2+ , The precursor solution containing Cs was added upon heating. + In the precursor solution, the mixed solution was heated at 120°C for 2 hours to synthesize CsPbBr3 crystal nuclei. Driven by thermal kinetic energy, the CsPbBr3 crystal nuclei grew along the mesoporous channels of the MOF, thus obtaining CsPbBr3 in solution. complex;

[0040] like Figure 5 The image shows the simulated X-ray diffraction (XRD) results of CsPbBr3, where the numbers on the diffraction peaks are the corresponding crystal plane indices.

[0041] Step 4: Add 5 ml of the heated mixture to a 30 ml centrifuge tube, add 20 ml of methyl acetate, let stand for 5 minutes, then centrifuge at 6000 rpm for 10 minutes. The precipitate obtained is CsPbBr3. Composite materials;

[0042] like Figure 6 The results of the X-ray diffraction (PXRD) test are shown. "■" indicates the diffraction peak corresponding to CsPbBr3 nanowires, and "▲" indicates the diffraction peak corresponding to PCN-600.

[0043] according to Figure 6 and Figure 4 , Figure 5 By comparison, it can be seen that the PCN-600 in the prepared composite material has a complete crystal structure and CsPbBr3 has a good cubic phase, especially its strong diffraction peak on the (200) crystal plane, which reflects the preferential orientation growth of CsPbBr3 nanowires along the PCN-600 channel direction.

[0044] Implementation Three:

[0045] like Figure 3 As shown, the MOF crystal used in this embodiment is PCN-600;

[0046] In this embodiment, a CH3NH3PbBr3 The process flow chart for preparing composite materials includes the following steps:

[0047] Step 1: The preparation method of the mesoporous multi-porous coordination network PCN-600 used in this embodiment is the same as the preparation method in Step 1 of Embodiment 2.

[0048] Step 2: Add the prepared 0.5 g PCN-600 single crystal solution to a precursor solution containing 0.138 g PbBr2, 0.5 mL oleic acid, 1 mL oleylamine, and 8 mL octadecene, and heat at 110 °C for 2 hours. Simultaneously, heat a precursor solution containing 0.11 g CH3NH3Br, 0.5 mL oleic acid, and 10 mL octadecene at 110 °C for 2 hours.

[0049] Step 3: Heat the Pb-containing... 2+ , The precursor solution contains CH3NH3 after heating. + ,Br - In the precursor solution, the mixed solution was heated at 120°C for 2 hours to synthesize CH3NH3PbBr3 crystal nuclei. Driven by thermal kinetic energy, the CH3NH3PbBr3 crystal nuclei grew along the mesoporous channels of the MOF, thus obtaining CH3NH3PbBr3 in solution. Complex.

[0050] Step 4: Add 5 ml of the heated mixture to a 30 ml centrifuge tube, add 20 ml of methyl acetate, let stand for 5 minutes, then centrifuge at 6000 rpm for 10 minutes. The precipitate obtained is CH3NH3PbBr3. Composite materials.

[0051] This invention proposes to arrange ABX3 nanowires using mesoporous channels of MOF crystals to form an ABX3 nanowire array. A method for preparing crystalline composite materials, wherein the ABX3 nanowire array in the composite material prepared by the method has high orderliness and orientation and is stable.

[0052] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing perovskite nanowires based on MOF mesoporous channel arrangement, characterized in that, Includes the following steps: Step 1: Add the mesoporous MOF crystal to the first precursor solution BX2 and heat it. BX2 is a metal halide, and it decomposes into divalent metal cations B. 2+ and halogen anion X - Under the adsorption of metal sites in MOF crystals and driven by thermal kinetic energy, divalent metal cations B... 2+ and halogen anion X - Entering the mesoporous channels of the MOF crystal; Step 2: Add the first precursor solution BX2, heated in Step 1, containing coordinating cation A. + The second precursor solution was used, and the mixed solution was heated for 2 hours to obtain the coordinating cation A in the mixed solution. + It enters the mesoporous channels of the MOF crystal and reacts with the divalent metal cation B. 2+ and halogen anion X - The reaction produces ABX3 crystal nuclei, which, driven by thermal kinetic energy and constrained by the steric hindrance of the MOF channels, grow along the mesopore direction of the MOF crystal, resulting in ABX3 nanowires. Mixed solutions of MOF crystal composite materials; Step 3: ABX3 nanowires were included in Step 2. Methyl acetate was added to the mixed solution of MOF crystal composite material to remove impurities. After standing and centrifugation, the precipitate was obtained, which was ABX3 nanowires. MOF crystal composite materials.

2. The method for preparing perovskite nanowires based on MOF mesoporous channel arrangement according to claim 1, characterized in that, The metal divalent cation B 2+ Includes: Pb 2+ or Sn 2+ The halide anion X - Including: CI - ,Br - or I - The first precursor solution comprises one of PbCl2, SnCl2, PbBr2, SnBr2, PbI2, and SnI2, wherein the coordinating cation A + Includes: CH3NH3 + or Cs + The second precursor solution includes one of CH3NH3Br or Cs2CO3.

3. The method for preparing perovskite nanowires based on MOF mesoporous channel arrangement according to claim 1, characterized in that, In step 3, the settling time is 5 to 15 minutes, and the centrifugation time is 5 to 15 minutes at 4000 to 8000 rpm.

4. The method for preparing perovskite nanowires based on MOF mesoporous channel arrangement according to claim 1, characterized in that, An accelerator was added to both the first precursor solution and the second precursor solution before heating. The accelerator included oleic acid, oleylamine, and octadecene.

5. The method for preparing perovskite nanowires based on MOF mesoporous channel arrangement according to claim 1, characterized in that, Steps 1 and 2 are carried out in a nitrogen-filled environment, and the heating temperature is 100-120℃.

6. The method for preparing perovskite nanowires based on MOF mesoporous channel arrangement according to claim 1, characterized in that, The MOF crystal mentioned in step 1 includes: Mesoporous channel type MOF single crystal.

7. The method for preparing perovskite nanowires based on MOF mesoporous channel arrangement according to claim 1, characterized in that, The volume ratio of methyl acetate added in step 3 to the volume of the mixed solution is 1:4 to 1:

6.

8. A perovskite nanowire based on MOF mesoporous channel arrangement prepared by the preparation method according to any one of claims 1 to 7, characterized in that, include: Perovskite nanowires and MOF crystals, wherein the perovskite nanowires are arranged in an array within the mesoporous channels of the MOF crystal, namely ABX3 nanowires. MOF crystal composite material, where A represents the organic cation CH3NH3. + or inorganic cation Cs + B represents a divalent metal cation, and X represents a halide anion.

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