Aqueous phase preparation method of perovskite nanomaterial

Abstract

The invention discloses an aqueous phase preparation method of a perovskite nanomaterial, comprising the following steps: S1, mixing; weighing 0.1-1 mmol of cesium trifluoroacetate and 0.2-0.6 mmol of PbBr 2 The powder is mixed in 10mL of N,N-dimethylacetamide; S2, obtain the first solution; heat the above mixed solution until the powder is completely dissolved to obtain the first solution; S3, obtain the second solution; take 0.2mmol of 4-bromobutyric acid and 0.2mmol of oleylamine and quickly inject them into the first solution, heat and maintain the temperature to obtain the second solution; S4, obtain the third solution; take 8-30mL of deionized water into a bottle, heat and maintain the temperature to obtain the third solution; S5, obtain the perovskite nano-base liquid; take 0.6-6mL of the second solution and quickly inject it into the third solution to obtain the perovskite nano-base liquid; S6, make the finished product. This application directly synthesizes CsPb in aqueous solution in one step 2 Br 5 Perovskite nanosheets have good dispersibility in aqueous solution, regular morphology, high synthesis efficiency, and can be stored for a long time at room temperature.

Description

Technical Field

[0001] The invention belongs to the technical field of nano material synthesis, and specifically relates to a water phase preparation method of perovskite nano material. Background Art

[0002] Since the organic-inorganic hybrid perovskite (OIHP) structure material was first used in solar cells, perovskite materials have immediately become a hot research field in optoelectronics. All-inorganic perovskite (CsPbX3, X = Cl, Br, I) breaks through the limitations of OIHP materials and has excellent optical properties such as adjustable luminescence spectrum, good color purity, and high fluorescence quantum yield. It is widely used in solar cells, light-emitting diodes, lasers, biological probes and other fields.

[0003] In addition, researchers have found that the performance of perovskite nanocrystals is strongly correlated with their shape, and the morphology control of perovskites has become a central topic of recent research. Compared with traditional spherical or cubic nanocrystals, one-dimensional perovskite nanorods have larger photon absorption cross-sections, lower non-radiative recombination rates, higher optical polarization, etc. They show better performance in applications such as light-emitting diodes, amplified spontaneous emission (ASE), and polarized luminescence.

[0004] However, the direct synthesis of high-quality perovskite nanorods is currently greatly restricted. Their ionic structure makes them extremely susceptible to corrosion by water, oxygen, etc. and have poor stability. There are relatively few studies on their direct synthesis in water, and related research topics are difficult to conduct.

[0005] Similarly, two-dimensional perovskite nanosheets usually have better conductivity and larger surface area, which helps improve optoelectronic performance. Their two-dimensional structure is also more stable, and they perform better in photovoltaic devices, photocatalysis, photoelectric sensors and other applications. However, they also face the problem of synthesis in water, and there are few related studies.

[0006] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention and should not be regarded as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the invention

[0007] The object of the present invention is to provide a method for preparing perovskite nanomaterials in water phase, which can solve the above problems.

[0008] In order to achieve the above-mentioned purpose, a specific embodiment of the present invention provides an aqueous phase preparation method of perovskite nanomaterials, comprising the following steps: S1, mixing; weighing 0.1-1mmol of cesium trifluoroacetate and 0.2-0.6mmol of PbBr2 powder and mixing them in 10mL of N,N-dimethylacetamide; S2, obtaining a first solution; heating the above-mentioned mixed solution until all the solids are dissolved to obtain a first solution; S3, obtaining a second solution; taking 0.2mmol of 4-bromobutyric acid and 0.2mmol of oleylamine and quickly injecting them into the first solution, heating and maintaining the temperature to obtain a second solution; S4, obtaining a third solution; taking 8-30mL of deionized water and putting it into a bottle, heating and maintaining the temperature to obtain a third solution; S5, obtaining a perovskite nano-base liquid; taking 0.6-6mL of the second solution and quickly injecting it into the third solution to obtain a perovskite nano-base liquid; S6, making a finished product; the perovskite nano-base liquid is allowed to stand for a period of time in a natural environment and is purified by centrifugation or centrifugal separation to obtain a finished product.

[0009] In one or more embodiments of the present invention, the perovskite nanomaterial includes perovskite nanorods, and the aqueous phase preparation method of the perovskite nanorods includes the following steps: S1, mixing; weighing cesium trifluoroacetate and PbBr2 powder and mixing them in 10mL of N,N-dimethylacetamide; S2, obtaining a fourth solution; heating the above mixed solution until all the solids are dissolved to obtain a fourth solution; S3, obtaining a fifth solution; taking 4-bromobutyric acid and oleylamine and quickly injecting them into the fourth solution, heating and maintaining the temperature to obtain a fifth solution; S4 , obtain the sixth solution; take 24mL of deionized water and put it into the bottle, heat and maintain the temperature to obtain the sixth solution; S5, obtain the CsPbBr3 nanocrystalline solution; take 2-3mL of the fifth solution and quickly inject it into the sixth solution to obtain the CsPbBr3 nanocrystalline solution; S6, make the finished product; let the CsPbBr3 nanocrystalline solution stand in a natural environment for 12h until the white substance generated in the solution precipitates to the bottom of the bottle, extract the solution on the upper layer of the precipitate for purification and centrifugation to obtain the CsPbBr3 perovskite nanorod solution.

[0010] In one or more embodiments of the present invention, the perovskite nanomaterial includes a perovskite nanosheet, and the aqueous phase preparation method of the perovskite nanosheet includes the following steps: S1, mixing; weighing cesium trifluoroacetate and PbBr2 powder and mixing them in 10mL of N,N-dimethylacetamide; S2, obtaining a seventh solution; heating the above mixed solution until all the solids are dissolved to obtain a seventh solution; S3, obtaining an eighth solution; taking 4-bromobutyric acid and oleylamine and quickly injecting them into the seventh solution, heating and maintaining the temperature to obtain an eighth solution; S4, obtain the ninth solution; take 12mL of deionized water and put it into a transparent glass vial, heat and maintain the temperature to obtain the ninth solution; S5, obtain the CsPb2Br5 perovskite nanosheet original solution; take 1-1.5mL of the eighth solution, and quickly inject it into the ninth solution to obtain the CsPb2Br5 perovskite nanosheet original solution; S6, make the finished product; centrifuge the CsPb2Br5 perovskite nanosheet original solution to separate the product, put the obtained supernatant into a bottle, and obtain the CsPb2Br5 perovskite nanosheet solution.

[0011] In one or more embodiments of the present invention, the mass of cesium trifluoroacetate in step S1 is 0.8 mmol, and the mass of PbBr2 is 0.4 mmol.

[0012] In one or more embodiments of the present invention, the mass of cesium trifluoroacetate in the step S1 is 0.2 mmol, and the mass of PbBr2 is 0.4 mmol.

[0013] In one or more embodiments of the present invention, the mass of 4-bromobutyric acid in step S3 is 0.2 mmol, and the mass of oleylamine is 0.2 mmol.

[0014] In one or more embodiments of the present invention, the heating temperature in step S2 is 55-65°C.

[0015] In one or more embodiments of the present invention, the heating temperature in step S3 is 55-65° C., and the temperature holding time in step S3 is 10-15 min.

[0016] In one or more embodiments of the present invention, the centrifuge speed in step S5 is 5000-8000 rpm / min.

[0017] In one or more embodiments of the present invention, the temperature holding time in step S4 is 5-10 min, and the heating temperature in step S4 is 50-60°C.

[0018] Compared with the prior art, the aqueous phase preparation method of a perovskite nanomaterial of the present invention has the following advantages:

[0019] 1) A one-step method for directly synthesizing CsPb2Br5 perovskite nanosheets in aqueous solution has been developed. The nanosheets have good dispersibility in aqueous solution, regular morphology, high synthesis efficiency, and can be preserved for a long time at room temperature. They can be applied to device fields that require room temperature aqueous solution.

[0020] 2) The method of the present invention not only induces the growth of nanosheets but also improves the stability by regulating the ratio of cesium trifluoroacetate and lead bromide;

[0021] 3) The preparation method is simple and easy, it can be synthesized in aqueous solution at room temperature, has low cost, and is suitable for popularization and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0023] Figure 1 This is a step diagram of a method for preparing a perovskite nanomaterial in an aqueous phase according to an embodiment of the present invention;

[0024] Figure 2 This is a TEM image of the perovskite nanorods at a scale of 200 nm in Example 2 of the present invention;

[0025] Figure 3 This is a TEM image of the perovskite nanorods at a scale of 100 nm in Example 2 of the present invention;

[0026] Figure 4 This is a HAADF-STEM image of the perovskite nanorods in Example 2 of the present invention;

[0027] Figure 5 is the EDS elemental diagram of the perovskite nanorods in Example 2 of the present invention;

[0028] Figure 6 This is a TEM image of the perovskite nanosheet at a scale of 100 nm in Example 3 of the present invention;

[0029] Figure 7 This is a TEM image of a 50 nm scale perovskite nanosheet in Example 3 of the present invention;

[0030] Figure 8 This is a HAADF-STEM image of the perovskite nanosheet in Example 3 of the present invention;

[0031] Fig. 9 is the EDS elemental diagram of the perovskite nanosheet in Example 3 of the present invention;

[0032] Fig.10 XRD comparison diagram of perovskite CsPbBr3 nanocrystals comparing the perovskite nanorods in Example 2 of the present invention and the perovskite nanosheets in Example 3;

[0033] Fig.11 FTIR comparison chart of perovskite CsPbBr3 nanocrystals comparing the perovskite nanorods in Example 2 of the present invention and the perovskite nanosheets in Example 3. DETAILED DESCRIPTION

[0034] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, the ordinary technicians in this field have obtained the above without creative work.

[0035] Example 1

[0036] like Figure 1 As shown, a method for preparing a perovskite nanomaterial in an aqueous phase in one embodiment of the present invention comprises the following steps:

[0037] S1, mixing; weigh 0.1-1 mmol of cesium trifluoroacetate and 0.2-0.6 mmol of PbBr2 powder and mix them in 10 mL of N, N-dimethylacetamide;

[0038] S2, obtaining a first solution; heating the mixed solution until all the solids are dissolved to obtain a first solution; wherein the heating temperature is 55-65°C

[0039] S3, obtaining a second solution; taking 0.2 mmol of 4-bromobutyric acid and 0.2 mmol of oleylamine and quickly injecting them into the first solution, heating and maintaining the temperature to obtain a second solution; wherein the heating temperature is 55-65°C, and the temperature maintenance time is 10-15 min.

[0040] S4, obtaining a third solution; taking 8-30 mL of deionized water and putting it into a bottle, heating and maintaining the temperature to obtain a third solution; wherein the temperature maintenance time is 5-10 min, and the heating temperature is 50-60°C.

[0041] S5, obtaining a perovskite nano-base liquid; taking 0.6-6 mL of the second solution, and quickly injecting it into the third solution to obtain a perovskite nano-base liquid; wherein the centrifuge speed is 5000-8000 rpm / min.

[0042] S6, making a finished product; the perovskite nano-base liquid is allowed to stand in a natural environment for a period of time and is purified by centrifugation or centrifugal separation to obtain a finished product.

[0043] It should be noted that the experimental instruments used in this application are a heatable magnetic stirrer, a desktop high-speed centrifuge (TG16-WS), a transmission electron microscope (JEOL-JEM 2100F), a Fourier transform infrared spectrometer (Nicolet iS-10), etc.

[0044] The present application adopts a simple and efficient synthesis strategy to directly synthesize perovskite nanomaterials in normal temperature aqueous solution, namely one-dimensional perovskite nanorods and two-dimensional perovskite nanosheets. By adjusting different concentrations of cesium trifluoroacetate and PbBr2 dissolved in N, N-dimethylacetamide, CsPbBr3 perovskite nanorods and CsPb2Br5 perovskite nanosheets can be prepared in aqueous solution by coordinating the surface ligands of 4-bromobutyric acid and oleylamine. The CsPbBr3 perovskite nanorods prepared by this method have regular morphology, excellent luminescence performance and high stability. The CsPb2Br5 perovskite nanosheets prepared by this method also have regular morphology, good luminescence performance and high stability.

[0045] Example 2

[0046] The perovskite nanomaterial includes perovskite nanorods, and the aqueous phase preparation method of the perovskite nanorods includes the following steps:

[0047] S1. Mixing: Weigh cesium trifluoroacetate and PbBr2 powder and mix them in 10 mL of N,N-dimethylacetamide;

[0048] The mass of cesium trifluoroacetate in step S1 was 0.8 mmol, and the mass of PbBr2 was 0.4 mmol.

[0049] S2, obtaining a fourth solution; heating the mixed solution until all the solids are dissolved to obtain a fourth solution;

[0050] S3, obtaining a fifth solution; taking 0.2 mmol of 4-bromobutyric acid and 0.2 mmol of oleylamine and rapidly injecting them into the fourth solution, heating and maintaining the temperature, to obtain a fifth solution;

[0051] S4, obtaining a sixth solution; taking 24 mL of deionized water and putting it into a bottle, heating and maintaining the temperature to obtain a sixth solution;

[0052] S5, obtaining a CsPbBr3 nanocrystal solution; taking 2-3 mL of the fifth solution, and rapidly injecting it into the sixth solution to obtain a CsPbBr3 nanocrystal solution;

[0053] S6, making the finished product; leaving the CsPbBr3 nanocrystal solution in a natural environment for 12 hours until the white substance generated in the solution finally precipitates to the bottom of the transparent glass bottle, then extracting the solution on the upper layer of the precipitate for purification by centrifugation, and the obtained supernatant is the CsPbBr3 perovskite nanorod solution.

[0054] Experimental test analysis

[0055] The CsPbBr3 perovskite nanorod nanomaterial prepared in this embodiment was subjected to microscopic testing and analysis to obtain TEM images and EDS images of the CsPbBr3 perovskite nanorods. Figures 2 to 5 As shown, the perovskite forms regular rods in the aqueous solution and has corresponding elements Cs, Pb, and Br. This shows that the method of this embodiment can prepare nanorods with good dispersibility and good crystallinity in aqueous solution.

[0056] The crystal structure and chemical composition of the CsPbBr3 perovskite nanorods prepared in this embodiment were tested and analyzed to obtain the XRD and FTIR images of the CsPbBr3 perovskite nanorods. Fig.10 and Fig.11 As shown, the crystal orientation distribution of the perovskite nanorods is different from that of the three-dimensional CsPbBr3 nanocrystals, and they grow anisotropically along the (110) crystal orientation and have a standard nanorod infrared structure spectrum. This shows that the CsPbBr3 perovskite nanorods prepared by the method of this embodiment have good crystal structure and chemical composition.

[0057] In summary, the CsPbBr3 perovskite nanorod nanomaterial prepared in this embodiment has good dispersibility in aqueous solution and regular morphology.

[0058] Example 3

[0059] The perovskite nanomaterial includes a perovskite nanosheet, and the aqueous phase preparation method of the perovskite nanosheet includes the following steps:

[0060] S1. Mixing: Weigh cesium trifluoroacetate and PbBr2 powder and mix them in 10 mL of N,N-dimethylacetamide;

[0061] The mass of cesium trifluoroacetate in step S1 was 0.2 mmol, and the mass of PbBr2 was 0.4 mmol.

[0062] S2, obtaining a seventh solution; heating the mixed solution until all the solids are dissolved to obtain a seventh solution;

[0063] S3, obtaining an eighth solution; taking 0.2 mmol of 4-bromobutyric acid and 0.2 mmol of oleylamine and rapidly injecting them into the seventh solution, heating and maintaining the temperature, to obtain an eighth solution;

[0064] S4, obtaining a ninth solution; taking 12 mL of deionized water and putting it into a bottle, heating and maintaining the temperature to obtain a ninth solution;

[0065] S5, obtaining a CsPb2Br5 perovskite nanosheet original solution; taking 1-1.5 mL of the eighth solution, and quickly injecting it into the ninth solution to obtain a CsPb2Br5 perovskite nanosheet original solution;

[0066] S6, making the finished product; centrifuging the CsPb2Br5 perovskite nanosheet original solution to separate the product, and putting the obtained supernatant into a transparent glass vial to obtain a CsPb2Br5 perovskite nanosheet solution.

[0067] Experimental test analysis

[0068] The CsPb2Br5 perovskite nanosheets prepared in this example were subjected to microscopic testing and analysis, and a TEM image of the CsPb2Br5 perovskite nanosheets was obtained. Figures 6 to 9 As shown, the perovskite forms regular sheets in the aqueous solution and has corresponding elements Cs, Pb, and Br. This shows that the method of this embodiment can prepare nanosheets with good dispersibility and good crystallinity in aqueous solution.

[0069] The crystal structure and chemical composition of the CsPb2Br5 perovskite nanosheets prepared in this embodiment were tested and analyzed to obtain the XRD and FTIR images of the CsPb2Br5 perovskite nanosheets. Fig.10 and Fig.11 As shown, the diffraction peaks of the perovskite nanosheets are clear, no diffraction peaks of other impurities appear, the purity is as high as 96%, and there is a standard infrared structure spectrum of the nanosheets. This shows that the CsPb2Br5 perovskite nanosheets prepared by the method of this embodiment have good crystal structure and chemical composition.

[0070] In summary, the CsPb2Br5 perovskite nanosheets prepared in this example have good dispersibility in aqueous solution and also have a regular morphology.

[0071] Among them, the difference between Example 2 and Example 3 is that Example 2 solves the problem that it is difficult to synthesize one-dimensional nanorods in aqueous solution, and Example 3 solves the problem that it is difficult to synthesize two-dimensional nanosheets in aqueous solution. The present application adopts a ligand-assisted reprecipitation synthesis method, using cesium trifluoroacetate and PbBr2 of different mass ratios to dissolve in N, N-dimethylacetamide, synergistically with the surface ligands of 4-bromobutyric acid and oleylamine, and then dispersed into an aqueous solution to prepare one-dimensional perovskite nanorods and two-dimensional perovskite nanosheets. The present application successfully synthesized one-dimensional perovskite nanorods and two-dimensional perovskite nanosheets with uniform morphology and size, good stability, and high photoluminescence quantum yield in aqueous solution.

[0072] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0073] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A method for preparing perovskite nanomaterials in aqueous phase, characterized in that: The perovskite nanomaterial includes perovskite nanorods, and the aqueous phase preparation method of the perovskite nanorods includes the following steps: S1. Mixing: Weigh 0.8 mmol of cesium trifluoroacetate and 0.4 mmol of PbBr2 powder and mix them in 10 mL of N,N-dimethylacetamide; S2, obtaining a fourth solution; heating the mixed solution until all the solids are dissolved to obtain a fourth solution; S3, obtaining a fifth solution; taking 0.2 mmol of 4-bromobutyric acid and 0.2 mmol of oleylamine and quickly injecting them into the fourth solution, heating and maintaining the temperature, to obtain a fifth solution; S4, obtaining a sixth solution; taking 24 mL of deionized water and putting it into a bottle, heating and maintaining the temperature to obtain a sixth solution; S5, obtaining a CsPbBr3 nanocrystal solution; taking 2-3 mL of the fifth solution, and rapidly injecting it into the sixth solution to obtain a CsPbBr3 nanocrystal solution; S6, making the finished product; leaving the CsPbBr3 nanocrystal solution in a natural environment for 12 hours until the white substance generated in the solution precipitates to the bottom of the bottle, extracting the solution on the upper layer of the precipitate for purification by centrifugation to obtain a CsPbBr3 perovskite nanorod solution.

2. The aqueous phase preparation method of a perovskite nanomaterial according to claim 1, characterized in that: The temperature holding time in step S4 is 5-10 min, and the heating temperature in step S4 is 50-60°C.

3. A method for preparing perovskite nanomaterials in aqueous phase, characterized in that: The perovskite nanomaterial includes a perovskite nanosheet, and the aqueous phase preparation method of the perovskite nanosheet includes the following steps: S1. Mixing: Weigh 0.2 mmol of cesium trifluoroacetate and 0.4 mmol of PbBr2 powder and mix them in 10 mL of N,N-dimethylacetamide; S2, obtaining a seventh solution; heating the mixed solution until all the solids are dissolved to obtain a seventh solution; S3, obtaining an eighth solution; taking 0.2 mmol of 4-bromobutyric acid and 0.2 mmol of oleylamine and quickly injecting them into the seventh solution, heating and maintaining the temperature, to obtain an eighth solution; S4, obtaining a ninth solution; taking 12 mL of deionized water and putting it into a bottle, heating and maintaining the temperature to obtain a ninth solution; S5, obtaining a CsPb2Br5 perovskite nanosheet original solution; taking 1-1.5 mL of the eighth solution, and quickly injecting it into the ninth solution to obtain a CsPb2Br5 perovskite nanosheet original solution; S6, making a finished product; centrifuging the CsPb2Br5 perovskite nanosheet original solution to separate the product, putting the obtained supernatant into a bottle, and obtaining a CsPb2Br5 perovskite nanosheet solution.

4. The aqueous phase preparation method of a perovskite nanomaterial according to claim 3, characterized in that: The heating temperature in step S2 is 55-65°C.

Images