CN108502918B - Synthesis method of inorganic perovskite nanowire - Google Patents

Abstract

The invention relates to a method for synthesizing inorganic perovskite nano wires. The method utilizes solvothermal method and anion exchange method to prepare the product with length up to several millimeters at lower temperatureCsPbBr with ultra-high length-diameter ratio of about 10nm in diameter₃Nanowires and CsPbI is obtained by a simple anion exchange process₃And CsPbCl₃A nanowire. The method has great promotion effect on the industrial mass preparation of inorganic perovskite nano wires, and is expected to further realize the application in the aspects of photoelectric detection, laser, solar cells and the like. The method is simple and controllable, high in yield, uniform in appearance, low in reaction temperature and suitable for large-scale production.

Description

A kind of synthetic method of inorganic perovskite nanowires

technical field

The invention relates to a method for synthesizing inorganic perovskite nanowires, in particular to a method for synthesizing _CsPbX3 (X=Cl, Br, I) nanowires with ultra-high aspect ratio, and belongs to the fields of new material preparation and nanotechnology .

Background technique

Inorganic perovskite CsPbX ₃ (X=Cl, Br, I) nanocrystals have excellent optoelectronic properties such as high fluorescence quantum efficiency, tunable emission wavelength and covering the entire visible spectrum (400-700 nm) and high absorption coefficient It has a wide range of applications in the fields of light-emitting diodes, solar cells and photodetection. Among them, one-dimensional inorganic perovskite nanowires have great application prospects in both solar cells and photodetection due to their unique structural characteristics, such as excellent photoconductivity and good lateral conductivity. Therefore, the exploration of inorganic calcium The synthesis method of titanium ore nanowires has become the research direction of many researchers. At present, the synthetic methods for preparing inorganic perovskite _CsPbX3 nanowires mainly include thermal injection method, recrystallization method and chemical vapor deposition (CVD). Among them, perovskite nanowires prepared by hot injection method (Muhammad I, Francesco Di S, Zhiya Dang, et al.Chem.Mater.2016, 28, 6450) are based on the synthesis of inorganic perovskite quantum dots by changing the reaction conditions obtained (Dandan Z, Samuel WE, Yi Yu, et al. J. Am. Chem. Soc. 2015, 137, 9230). The limitations of this synthesis method are: the experimental operation is cumbersome, requires dehydration and an inert atmosphere, and the yield of the prepared nanowires is low, so it is difficult to achieve large-scale preparation. The patent "A method for preparing lead-halide perovskite nanowires by recrystallization method" (Patent Publication No. CN 106629835A) reported the preparation of lead-halide perovskite CsPbI ₃ nanowires by recrystallization method. First, the precursor of the nanowires was spin-coated On the substrate, a mixed solvent of poor solvent and polar aprotic solvent was added, and then perovskite _CsPbI3 nanowires were prepared under high temperature annealing conditions. However, CsPbBr ₃ and CsPbCl ₃ nanowires are not prepared by this recrystallization method, and the preparation process requires a high annealing temperature, and the final morphology of the nanowires will be affected due to the uneven spin coating during mass preparation. Preparation of perovskite nanowires by chemical vapor deposition CVD method "A preparation method of nano-scale laser array" (patent publication number CN 107104357A) to prepare perovskite with a diameter of 200-800nm and a length of 10-80μm in plane alignment Mineral nanowires. Pan Anlian's group also prepared CsPbBr ₃ ultralong nanowires with planar alignment by chemical vapor deposition (Muhammad S, Xuehong Z, Xiaoxia W, et al.J.Am.Chem.Soc, 2017,139,15592), And assembled a photodetector with fast response. However, this method uses relatively expensive sapphire as a substrate, and requires high heating temperature and ventilation process, so this method still has certain limitations for the large-scale preparation of inorganic perovskite nanowires.

The patent "a synthetic method of inorganic perovskite nanosheets" (publication number CN107522225A) adopts a solvothermal method, first adding cesium carbonate to the mixed solution (the volume ratio of octadecene and oleic acid is 7:1 ) to form a precursor solution of cesium, wherein the molar concentration of cesium is 0.15-0.20mol/L; subsequently the metal lead halide is added to the mixed solution (octadecene: oleic acid: oleylamine in a volume ratio of 7:1: 1), form the precursor solution of lead halide, wherein the molar concentration of lead halide is 0.07-0.10mol/L; Then the precursor solution of above-mentioned cesium and the precursor solution of lead halide are mixed with volume ratio 1:9-1:15 , reacted in a reactor, and obtained sheet-like perovskite CsPbX ₃ nanosheets. Although this patent realizes the controllable synthesis of CsPbX ₃ nanosheets, the obtained CsPbX ₃ nanosheets have poor stability, and the controllable synthesis of one-dimensional CsPbX ₃ nanowires cannot be achieved through the existing technical parameters. The patent "a synthetic method of cesium lead halide Cs ₄ PbX ₆ nanocrystals" (application number 201810126310.6) also adopts a solvothermal method, wherein cesium carbonate is first added to the mixed solution (the volume ratio of octadecene and oleic acid) is 4:1) to form a precursor solution of cesium, wherein the molar concentration of cesium is 0.30-0.45mol/L; then the metal lead halide is added to the mixed solution (the volume ratio of octadecene:oleic acid:oleylamine is 10:1:1) to form a precursor solution of lead halide, wherein the molar concentration of lead halide is 0.08-0.12mol/L; then the precursor solution of the above-mentioned cesium and lead halide is in a volume ratio of 1:4- 1:2 mixing, reacting in a reactor, then centrifuging, washing, drying and obtaining solid powder Cs ₄ PbX ₆ nanocrystals. This patent realizes the controllable synthesis of Cs ₄ PbX ₆ nanocrystals, but the controllable synthesis of one-dimensional nanowires cannot be achieved through the existing technical parameters.

SUMMARY OF THE INVENTION

The present invention provides an inorganic perovskite CsPbX ₃ (X=Cl, Br, I) in view of the low yield of the current method for preparing perovskite CsPbX ₃ nanowires, the complexity of the experimental process, the high temperature treatment process and the high cost, etc. ) method for the synthesis of nanowires. In this method, ultra-high aspect ratio nanowires with a length of several millimeters and a diameter of only about 10 nanometers were prepared at low temperature by solvothermal method and anion exchange method, and _CsPbI3 was obtained through a simple anion exchange process. and CsPbCl ₃ nanowires, which have a great promotion effect on the industrialized mass preparation of inorganic perovskite nanowires, and are expected to be further applied in photodetection, laser and solar cells. The invention is simple and controllable, has high yield, uniform appearance and low reaction temperature, and is suitable for large-scale production.

The technical scheme of the present invention is:

A method for synthesizing inorganic perovskite nanowires, comprising the following steps:

Step 1, adding cesium carbonate (Cs ₂ CO ₃ ) into mixed solution A, stirring at 110-160° C. for 15-35 min, and then naturally cooling to room temperature to form a cesium precursor solution;

Wherein, the mixed solution A is composed of oleic acid and octadecene, wherein the volume ratio of oleic acid: octadecene=1:8; in the precursor solution of cesium, the molar concentration of cesium is 0.12-0.25mol/L;

Step 2, adding lead bromide (PbBr ₂ ) into mixed solution B, stirring at 90-130° C. for 15-35 min, and then cooling to room temperature in an ice-water bath to form a precursor solution of lead bromide;

Wherein, the mixed solution B is composed of oleylamine, oleic acid and octadecene, wherein the volume ratio of oleylamine:oleic acid:octadecene=1:1:8, in the precursor solution of lead bromide, the The molar concentration is 0.09-0.15mol/L;

In step 3, the precursor solution of cesium is heated to 60-100 ° C, transferred to the reaction kettle and cooled to room temperature naturally, the precursor solution of lead bromide is added, and ultrasonically treated at room temperature for 15-35 min to obtain mixed solution D;

Among them, the volume ratio of the precursor solution of lead bromide: the precursor solution of cesium=7:1-16:1;

In step 4, the mixed solution D obtained in the above step 3 is reacted at a temperature in the range of 80-150 ° C for 30-90 h, and then the reactant solution E is obtained by natural cooling;

In step 5, the reactant E obtained in the previous step is washed after centrifugation to obtain the final product inorganic perovskite CsPbBr ₃ nanowires.

When the product is CsPbCl ₃ , CsPbCl _x Br _3-x , CsPbBr _x I _3-x or CsPbI ₃ nanowires (wherein, 0<x<3), the following steps are also included:

Step 6, adding the _CsPbBr nanowires obtained above into a non-polar solvent to obtain dispersion F; wherein, the non-polar solvent is generally toluene, n-hexane or n-octane; the concentration of dispersion F is 0.015mmol/L- 0.025mmol/L;

The obtained dispersion liquid F is added to the precursor solution of lead iodide or lead chloride at 40-85°C to obtain mixed solution G;

Among them, the volume ratio of the precursor solution of lead iodide or lead chloride: dispersion liquid F=1:1-5:1;

The preparation method of the precursor solution of lead iodide or lead chloride includes the following steps: adding lead iodide (PbI ₂ ) or lead chloride (PbCl ₂ ) into the mixed solution C, at 100-170° C. Under stirring for 15-35min, then cooled to room temperature under the condition of ice-water bath to form the precursor solution of lead iodide or lead chloride;

Wherein, if lead iodide (PbI ₂ ) is added to the mixed solution C, the C solution is composed of oleylamine, oleic acid and octadecene, wherein the volume ratio of oleylamine:oleic acid:octadecene=1:1:8 , in the precursor solution of lead iodide, the molar concentration of lead iodide is 0.09-0.15mol/L; if lead chloride (PbCl ₂ ) is added to the mixed solution C, the C solution is composed of trioctylphosphine, oleic acid , oleylamine and octadecene, wherein the volume ratio of trioctylphosphine:oleic acid:oleylamine:octadecene=1:1:1:8, in the precursor solution of lead chloride, the molar concentration of lead chloride is 0.09-0.15mol/L;

Step 7, the mixed solution G obtained in the previous step is washed after centrifugation to obtain the final product inorganic perovskite CsPbCl ₃ , CsPbCl _x Br _3-x , CsPbBr _x I _3-x or CsPbI ₃ nanowires;

The centrifugal rotation speed in steps 5 and 7 is 5000-10000 r/min, and the centrifugation time is 5-10 min; the washing reagent is acetone, toluene or ethyl acetate.

The non-polar solvent is one or both of n-hexane, toluene and n-octane.

The essential features of the present invention are:

The present invention successfully prepares perovskite CsPbX ₃ (X=Cl, Br, I) nanowires by means of solvothermal method and anion exchange. The longer reaction time at lower temperature in the solvothermal reaction process enables the precursor to fully function under the action of surface ligands, and the nanowires can continue to grow along a specific direction, finally obtaining CsPbBr ₃ nanometers with better crystallinity. And CsPbBr ₃ nanowires were used as templates to prepare CsPbI ₃ and CsPbCl ₃ nanowires with ultra-high aspect ratio by anion exchange at lower temperature.

Firstly, cesium carbonate and lead bromide are respectively dissolved in the solvent of octadecene mixed with surface ligands (steps 1 and 2), so that the surface ligands are evenly wrapped on the surface of the precursor, which can better control the reaction process; At room temperature, the cesium carbonate precursor and the lead bromide precursor are fully mixed and transferred to the reaction kettle (step 3), and the reaction time and reaction temperature of the dissolution heat are controlled to make the two precursors fully nucleate and grow slowly. Centrifuge After the treatment, the reactant was obtained, and the excess unreacted organic matter was washed with ethyl acetate to finally obtain CsPbBr ₃ ultra-long nanowires (steps 4 and 5). Using the prepared CsPbBr ₃ ultra-long nanowires as a template, the dispersion liquid dispersed with CsPbBr ₃ nanowires is added to the lead iodide or lead chloride precursor solution by anion exchange method, and the temperature of the precursor is used to control the anion At the exchange rate, the Br element is gradually or completely exchanged into the I element or the Cl element (step 6), the obtained reactant is subjected to centrifugation, and washed with acetone and other reagents to obtain CsPbCl ₃ , CsPbCl _x Br _3-x , CsPbBr _x I _3-x or CsPbI ₃ nanowires (step 7). By controlling the solvothermal reaction temperature and reaction time, this method enables the oleylamine oleate surfactant to fully function, promotes the growth of the perovskite along a specific direction, and finally generates a CsPbBr3 _perovskite with an ultra-high aspect ratio. nanowires, and obtained perovskite nanowires of other halogen elements with the same morphology by anion exchange.

The beneficial effects of the present invention are:

1. The diffraction peaks of the XRD spectrum of the inorganic perovskite nanowires synthesized by the method of the present invention are clear, which are the inorganic perovskite CsPbBr ₃ structure, the crystal structure conforms to CsPbBr ₃ -PDF#54-752, and there is no diffraction of other impurity phases. The peak appears, and the purity is as high as 97%; the SEM of the perovskite CsPbBr ₃ nanowires is shown in Figure 2, showing an ultra-fine fibrous shape with a length of several millimeters; the TEM of the CsPbBr ₃ nanowires is shown in Figure 3, with a diameter of 12 nm, with ultra-high The aspect ratio of CsPbBr ₃ nanowires is shown in Figure 8, with a narrow half-peak width and the largest emission peak at 519 nm; the UV-Vis absorption spectrum of CsPbBr ₃ nanowires is shown in Figure 9, and the characteristic absorption peak is at 508 nm .

2. In the present invention, by controlling the solvothermal reaction temperature and reaction time, the oleylamine oleate surfactant can fully play the role of regulating crystal growth, resulting in the continuous growth of perovskite along a specific direction, and finally forming a super-high aspect ratio. Nanowires.

3. The present invention realizes the preparation and synthesis of CsPbBr ₃ , CsPbCl ₃ and CsPbI ₃ perovskite nanowires by means of solvothermal method and anion exchange. The equipment required for the experiment is simple, no harsh experimental conditions are required, and the reaction is controllable. Strongly suitable for industrial production.

4. The inorganic perovskite nanowires prepared and synthesized by the present invention have narrow half-peak width, high purity and good crystallinity, and can be used in fields such as photodetectors, solar cells and the like.

Description of drawings

1 is the XRD pattern of the inorganic perovskite CsPbBr ₃ nanowires obtained in Example 1.

2 is a SEM image of the inorganic perovskite CsPbBr ₃ nanowires obtained in Example 1.

3 is a TEM image of the inorganic perovskite CsPbBr ₃ nanowire obtained in Example 1.

4 is a SEM image of the inorganic perovskite CsPbI ₃ nanowires obtained in Example 2.

5 is a TEM image of the inorganic perovskite CsPbI ₃ nanowires obtained in Example 2.

6 is a SEM image of the inorganic perovskite CsPbCl ₃ nanowires obtained in Example 3.

FIG. 7 is a TEM image of the inorganic perovskite CsPbCl ₃ nanowire obtained in Example 3. FIG.

8 is the fluorescence emission spectra of the inorganic perovskite CsPbBr ₃ , CsPbI ₃ and CsPbCl ₃ nanowires obtained in Examples 1-3.

9 is the ultraviolet-visible absorption spectrum of the inorganic perovskite CsPbBr ₃ , CsPbI ₃ and CsPbCl ₃ nanowires obtained in Examples 1-3.

10 is a SEM image of the inorganic perovskite CsPbBr _x I _3-x nanowire obtained in Example 4.

FIG. 11 is a SEM image of the inorganic perovskite CsPbCl _x Br _3-x nanowire obtained in Example 5. FIG.

Detailed ways

The invention will be further explained and described below in conjunction with the embodiments and the accompanying drawings

Example 1

Step 1. Weigh 0.7 mmol of cesium carbonate (Cs ₂ CO ₃ ) and add it to a flask containing 1.0 mL of oleic acid and 8.0 mL of octadecene, stir at 120°C for 25 min to completely dissolve the cesium carbonate powder, and then naturally cool to To room temperature, a cesium precursor solution was formed.

Step 2. Weigh 2.0 mmol of lead bromide and add it to a flask containing 2.0 mL of oleic acid, 2.0 mL of oleylamine and 16 mL of octadecene, stir at 110°C for 25 min to completely dissolve the lead bromide powder, and then use an ice-water bath for cooling To room temperature, a lead bromide precursor solution is formed.

Step 3. Heat the cesium oleate precursor solution obtained in step 1 to 80°C, measure 2 mL, and add it to the reactor, cool to room temperature, then add 20 mL of the lead bromide precursor obtained in step 2 at room temperature, and ultrasonically treat it. 15min.

Step 4. The mixed solution obtained in step 3 was reacted at a heating temperature of 120° C. for 70 hours, and after the reaction was completed, it was naturally cooled to room temperature.

Step 5. The product obtained in Step 4 is centrifuged at 8000 r/min for 7 min, then the upper organic layer is discarded, and the obtained bottom sediment is washed with acetone to obtain the product CsPbBr ₃ nanowires (0.3 mmol is 0.174 g), and the The dispersion was stored in 20 mL of n-hexane.

All the above operating processes are in an open environment without inert protective gas and strict dehydration and deoxygenation treatment.

The XRD of the CsPbBr ₃ nanowires obtained in this Example 1 is shown in Figure 1, the crystal structure conforms to CsPbBr ₃ -PDF#54-752, and the crystallinity of the perovskite nanowires is good; the SEM of the perovskite CsPbBr ₃ nanowires is shown in the figure 2, showing an ultra-fine fibrous shape with a length of several millimeters; the TEM of the CsPbBr ₃ nanowires is shown in Figure 3, with a diameter of 12 nm, with an ultra-high aspect ratio; the fluorescence spectrum of the CsPbBr ₃ nanowires is shown in Figure 8, with Narrow half-peak width, the largest emission peak is at 519nm; the UV-vis absorption spectrum of CsPbBr ₃ nanowires is shown in Figure 9, and the characteristic absorption peak is at 508nm.

Example 2

Step 1. Weigh 0.7 mmol of cesium carbonate and add it to a flask containing 1.0 mL of oleic acid and 8.0 mL of octadecene, stir at 120°C for 25 minutes to completely dissolve the cesium carbonate powder, and then naturally cool to room temperature to form a cesium precursor body solution.

Step 2. Weigh 2.0 mmol of lead bromide and add it to a flask containing 2.0 mL of oleic acid, 2.0 mL of oleylamine and 16 mL of octadecene, stir at 110°C for 25 min to completely dissolve the lead bromide powder, and then use an ice-water bath for cooling To room temperature, a lead bromide precursor solution is formed.

Step 3. Weigh 2.0 mmol of lead iodide and add it to a flask containing 2.0 mL of oleic acid, 2.0 mL of oleylamine and 16 mL of octadecene, stir at 110°C for 25 min to completely dissolve the lead iodide powder, and then use an ice-water bath for cooling To room temperature, a lead iodide precursor solution is formed.

Step 4. Heat the cesium oleate precursor solution obtained in step 1 to 80°C, measure 2 mL, and add it to the reaction kettle, cool it to room temperature, and then add 20 mL of the lead bromide precursor obtained in step 2 at room temperature. Ultrasonic treatment 15min.

In step 5, the mixed solution obtained in step 4 was reacted at a heating temperature of 120° C. for 70 hours, and after the reaction was completed, it was naturally cooled to room temperature.

Step 6. The product obtained in Step 5 was centrifuged at 8000 r/min for 7 min, then the upper organic layer was discarded, and the bottom sediment was washed with acetone to obtain the product CsPbBr ₃ nanowires (0.3 mmol), which were dispersed in 20mL of n-hexane.

Step 7. Add 5 mL of the CsPbBr ₃ nanowire dispersion obtained in step 6 to the 20 mL lead iodide precursor solution obtained in step 3 and heated to 80° C., and obtain a crude solution after the reaction is completed.

Step 8. After the crude solution obtained in step 7 was centrifuged at 8000 r/min for 7 min, the upper organic layer was discarded, and the bottom sediment obtained was washed with acetone to obtain the product _CsPbI nanowires, which were dispersed in 10 mL of n-hexane middle. All the above operating processes are in an open environment without inert protective gas and strict dehydration and deoxygenation treatment.

The SEM of the CsPbI ₃ nanowires obtained in Example 2 is shown in Figure 4, showing an ultra-fine fiber shape with a length of several millimeters; the TEM of the CsPbI ₃ nanowires is shown in Figure 3, with a diameter of 12 nm and an ultra-high aspect ratio. The fluorescence spectrum of CsPbI ₃ nanowires is shown in Figure 8, and the maximum emission peak is at 685 nm; the ultraviolet-visible absorption spectrum of CsPbI ₃ nanowires is shown in Figure 9, and the characteristic absorption peak is at 678 nm.

Example 3

Step 1. Weigh 0.7 mmol of cesium carbonate and add it to a flask containing 1.0 mL of oleic acid and 8.0 mL of octadecene, stir at 120°C for 25 minutes to completely dissolve the cesium carbonate powder, and then naturally cool to room temperature to form a cesium precursor body solution.

Step 2. Weigh 2.0 mmol of lead bromide and add it to a flask containing 2.0 mL of oleic acid, 2.0 mL of oleylamine and 16 mL of octadecene, stir at 110°C for 25 min to completely dissolve the lead bromide powder, and then use an ice-water bath for cooling To room temperature, a lead bromide precursor solution is formed.

Step 3. Weigh 2.0 mmol of lead chloride and add it to a flask containing 2.0 mL of oleic acid, 2.0 mL of oleylamine, 2.0 mL of trioctylphosphine and 16 mL of octadecene, and stir at 110 ° C for 25 min to make the lead chloride powder completely Dissolution followed by cooling to room temperature using an ice-water bath resulted in a lead chloride precursor solution.

Step 4. Heat the cesium oleate precursor solution obtained in step 1 to 80 °C, weigh 2 mL, and add it to the reaction kettle. After cooling to room temperature, add the lead bromide precursor obtained in step 2 at room temperature, and ultrasonically treat it for 15 minutes. .

Step 5. The mixed solution obtained in step 4 was reacted at a heating temperature of 120° C. for 70 hours, and after the reaction was completed, it was naturally cooled to room temperature.

Step 6. The product obtained in Step 5 was centrifuged at 8000 r/min for 7 min, then the upper organic layer was discarded, and the bottom sediment was washed with acetone to obtain the product CsPbBr ₃ nanowires (0.3 mmol), which were dispersed in 20mL of n-hexane.

Step 7: Take 5 mL of the CsPbBr ₃ nanowire dispersion obtained in step 6 and add it to the 22 mL lead chloride precursor solution obtained in step 3 and heated to 60° C. After the reaction is completed, a crude solution is obtained.

Step 8. After the crude solution obtained in step 7 was centrifuged at 8000 r/min for 7 min, the upper organic layer was discarded, and the bottom sediment obtained was washed with acetone to obtain the product _CsPbCl nanowires, which were dispersed in 10 mL of n-hexane middle. All the above operating processes are in an open environment without inert protective gas and strict dehydration and deoxygenation treatment.

The SEM of the CsPbCl ₃ nanowires obtained in Example 3 is shown in Figure 6, showing an ultra-fine fibrous shape with a length of several millimeters; the TEM of the CsPbCl ₃ nanowires is shown in Figure 7, with a diameter of 12 nm, with an ultra-high aspect ratio; The fluorescence spectrum of CsPbCl ₃ nanowires is shown in Figure 8, with a narrow half-peak width and the largest emission peak at 410 nm; the ultraviolet-visible absorption spectrum of CsPbCl ₃ nanowires is shown in Figure 9, and the characteristic absorption peak is at 404 nm.

Example 4

The CsPbBr ₃ nanowire dispersion in step 7 in Example 2 was changed from 5 mL to 15 mL, and other operations were the same as in Example 2, to obtain CsPbBr _x I _3-x nanowires. The SEM of the CsPbBr _x I _3-x nanowires obtained in Example 4 is shown in Fig. 10, showing the shape of ultra-fine fibers, and the length can reach several millimeters.

Example 5

The CsPbBr ₃ nanowire dispersion liquid in step 7 in Example 3 was changed from 5 mL to 15 mL, and other operations were the same as in Example 3 to obtain CsPbCl _x Br _3-x nanowires. The SEM of the CsPbCl _x Br _3-x nanowires obtained in Example 5 is shown in Fig. 11 , showing an ultra-fine fibrous shape with a length of several millimeters.

By adjusting the solvothermal reaction temperature and reaction time, _{perovskite CsPbBr3} nanowires with ultra-high aspect ratio (a length of several millimeters and a diameter of only about 10 nanometers) were obtained. CsPbCl ₃ , CsPbCl _x Br _3-x , CsPbBr _x I _3-x and CsPbI ₃ nanowires were prepared by the method, and the ultra-high aspect ratio characteristics of CsPbBr ₃ nanowires were retained. During the ion exchange process, the temperature of the precursor PbI ₂ or PbCl ₂ will affect the speed of the anion exchange, and the ratio of the solution in which the CsPbBr ₃ nanowires are dispersed to the precursor PbI ₂ or PbCl ₂ will also affect the progress of the exchange reaction. The ratio of the two can obtain perovskite nanowires with different luminescence peak positions and different compositions, which provides an experimental basis for the controllable synthesis of nanowires, and has an important impetus for its applications in photodetection and solar cells. effect.

Matters not addressed in the present invention are known in the art.

Claims (2)

1. a synthetic method of inorganic perovskite nanowire is characterized in that the method comprises the steps: Step 1, adding cesium carbonate (Cs ₂ CO ₃ ) into mixed solution A, stirring at 110-160° C. for 15-35 min, and then naturally cooling to room temperature to form a precursor solution of cesium; Wherein, the mixed solution A is composed of oleic acid and octadecene, wherein the volume ratio of oleic acid: octadecene=1:8; in the precursor solution of cesium, the molar concentration of cesium is 0.12-0.25 mol/L; Step 2, adding lead bromide (PbBr ₂ ) into mixed solution B, stirring at 90-130° C. for 15-35 min, and then cooling to room temperature in an ice-water bath to form a lead bromide precursor solution; Among them, the mixed solution B is composed of oleylamine, oleic acid and octadecene, wherein the volume ratio of oleylamine:oleic acid:octadecene=1:1:8, in the precursor solution of lead bromide, the lead bromide The molar concentration is 0.09-0.15 mol/L; In step 3, the precursor solution of cesium is heated to 60-100°C, transferred to the reaction kettle and cooled to room temperature naturally, the precursor solution of lead bromide is added, and ultrasonically treated at room temperature for 15-35 min, to obtain mixed solution D; Among them, the volume ratio of the precursor solution of lead bromide: the precursor solution of cesium=7:1-16:1; In step 4, the mixed solution D obtained in the above step 3 is reacted at a temperature in the range of 80-150 ° C for 30-90 h, and then the reactant solution E is obtained by natural cooling; Step 5, the reactant E obtained in the previous step is washed after centrifugation to obtain the final product inorganic perovskite CsPbBr ₃ nanowires; When the product is CsPbCl ₃ , CsPbCl _x Br _3-x , CsPbBr _x I _3-x or CsPbI ₃ nanowires, the following steps are also included: Step 6, adding the _CsPbBr nanowires obtained above into a non-polar solvent to obtain dispersion F; wherein, the non-polar solvent is toluene, n-hexane or n-octane; the concentration of dispersion F is 0.015 mmol/L-0.025 mmol/L; The obtained dispersion liquid F is added to the precursor solution of lead iodide or lead chloride at 40-85°C to obtain mixed solution G; Among them, the volume ratio of the precursor solution of lead iodide or lead chloride: dispersion liquid F=1:1-5:1; The preparation method of the precursor solution of lead iodide or lead chloride includes the following steps: adding lead iodide (PbI ₂ ) or lead chloride (PbCl ₂ ) into the mixed solution C, at 100-170° C. Stir for 15-35 min, and then cool to room temperature in an ice-water bath to form a precursor solution of lead iodide or lead chloride; Wherein, if lead iodide (PbI ₂ ) is added to the mixed solution C, the C solution is composed of oleylamine, oleic acid and octadecene, wherein the volume ratio of oleylamine:oleic acid:octadecene=1:1:8 , in the precursor solution of lead iodide, the molar concentration of lead iodide is 0.09-0.15mol/L; if lead chloride (PbCl ₂ ) is added to the mixed solution C, the C solution is composed of trioctylphosphine, oleic acid , oleylamine and octadecene, wherein the volume ratio of trioctylphosphine: oleic acid: oleylamine: octadecene = 1:1:1:8, in the precursor solution of lead chloride, the molar concentration of lead chloride is 0.09-0.15 mol/L; Step 7, the mixed solution G obtained in the previous step is washed after centrifugation to obtain the final product inorganic perovskite CsPbCl ₃ , CsPbCl _x Br _3-x , CsPbBr _x I _3-x or CsPbI ₃ nanowires; wherein, 0<x<3. 2. the synthetic method of inorganic perovskite nanowire as claimed in claim 1, is characterized in that the centrifugal rotating speed in described step 5 and step 7 is 5000-10000 r/min, and centrifugal time is 5-10 min; Washing reagents are acetone, toluene or ethyl acetate.

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