Method for preparing perovskite ultra-long nanowire in air environment

Abstract

The invention discloses a method for preparing a perovskite ultra-long nanowire in an air environment. Comprising the following steps: S1, preparing a precursor solution A; s2, preparing a precursor solution B; s3, preparing a precursor solution C; s4, preparing an original solution of an initial nanowire; and S5, obtaining the clean perovskite ultra-long nanowire. Compared with traditional perovskite nanocrystals, due to the one-dimensional long-range structure of the ultra-long perovskite nanowires, charges can be transmitted more efficiently and more stably in the axial direction of the nanowires, the probability of charge recombination is reduced, and therefore the performance of electronic devices is remarkably improved. And secondly, the long perovskite nanowire has better stability. Moreover, the longer structure of the long perovskite nanowire can increase the absorption path of light, so that the light energy can be captured more effectively, which is of great significance to the performance improvement of photoelectric devices such as solar cells and photoelectric sensors.

Description

Technical Field

[0001] The invention relates to the field of nano functional materials and display lighting, and in particular to a method for preparing ultra-long perovskite nanowires in an air environment. Background Art

[0002] Halide perovskite nanocrystals exhibit a series of extremely outstanding characteristics, such as excellent fluorescence quantum yield, which indicates that it can produce brighter and more efficient fluorescence, and the narrow half-peak width, a remarkable characteristic, makes the color purity of the light it emits reach an extremely high level, and the color recognition is greatly improved. The remarkable feature of low nucleation temperature greatly reduces the difficulty and cost of preparation, creating feasible conditions for large-scale production. In addition, the fluorescence emission peak with adjustable composition and size gives it great flexibility and customizability, and can accurately customize specific wavelengths of light according to different actual needs. Because of this, halide perovskite nanocrystals have been widely used in many fields such as solar cells, light-emitting diodes, and photodetectors.

[0003] However, even though metal halide perovskite quantum dots have made great achievements in synthesis, characterization, theory, and device application, the problem of poor stability of metal halide perovskite quantum dots has never been properly and effectively solved. When metal halide perovskite quantum dots are exposed to moisture, oxygen, high temperature, and light for a long time, material degradation usually occurs. Such a situation will cause serious performance degradation of metal halide perovskite quantum dots during a series of processes such as storage, characterization, and processing, which greatly restricts the promotion of perovskite quantum dots in practical applications and their further development trend.

[0004] Compared with perovskite quantum dots, ultra-long perovskite nanowires perform better in carrier transport. Due to its one-dimensional long-range structure, charges can be transported more efficiently and stably along the axis of the nanowire, reducing the probability of charge recombination, thereby significantly improving the performance of electronic devices. Secondly, ultra-long perovskite nanowires have better stability. Compared with perovskite quantum dots, it is less prone to degradation and performance degradation in the face of adverse environmental factors such as humidity, oxygen, temperature changes and light, and can maintain a good working state for a long time. Furthermore, long perovskite nanowires have higher optical absorption efficiency. Its longer structure can increase the absorption path of light, so that it can capture light energy more effectively, which is of great significance for the performance improvement of optoelectronic devices such as solar cells. In addition, long perovskite nanowires also have more advantages in flexibility. It can better adapt to deformations such as bending and stretching, which provides more favorable conditions for the development of flexible and wearable optoelectronic devices. For example, in photodetectors, long perovskite nanowires can achieve faster and more sensitive light response with their excellent carrier transport and optical absorption properties. In the field of flexible displays, its good flexibility can meet the needs of various complex application scenarios. Summary of the invention

[0005] The present invention provides a method for preparing ultra-long perovskite nanowires in an air environment, and the specific steps are as follows:

[0006] S1: prepare precursor solution A;

[0007] S2: prepare precursor solution B;

[0008] S3: preparing precursor solution C;

[0009] S4: preparing the original solution of the initial ultra-long nanowires;

[0010] S5: Obtain ultra-long perovskite nanowires.

[0011] Furthermore, step S1 is specifically as follows:

[0012] The A salt, the organic ligand and the non-coordinating solvent are fully mixed and stirred continuously for a predetermined time under specific temperature conditions, thereby successfully obtaining a clear and transparent precursor solution A.

[0013] Furthermore, step S2 is specifically as follows:

[0014] The lead source, halogen source and non-coordinating solvent are mixed and vacuumized, and then reacted at a set temperature for a specific time, and then an inert gas is introduced to continue the reaction, and then the temperature is raised to a certain temperature, and the reaction is continued for a certain time, and then a certain amount of organic anion ligand and organic cationic ligand are added, and heated and stirred for a certain time. The precursor solution B can be obtained until the solution is clear and transparent.

[0015] Furthermore, step S3 is specifically as follows:

[0016] Precursor solution A and precursor solution B are heated to different temperatures, a certain amount of precursor solution A is added to precursor solution B, and then a certain amount of polar solvent is added, and then the solution is quickly cooled to room temperature; precursor solution C is obtained.

[0017] Further, step S4 is specifically as follows:

[0018] The precursor solution C is placed in a reaction kettle, and then placed in an oven at a certain temperature to react for a certain period of time, and then the solution is quickly cooled to room temperature to obtain the original solution of ultra-long nanowires.

[0019] Furthermore, step S5 is specifically as follows:

[0020] A predetermined amount of anti-solvent is added to the solution prepared in S4 for centrifugation. Subsequently, the obtained precipitate is added to the solvent for dispersion again, and the above centrifugation steps are repeated multiple times to completely remove the reaction waste generated during the synthesis of the ultra-long perovskite nanowires, and finally, clean ultra-long perovskite nanowires are successfully obtained.

[0021] Further, in step S1, salt A is one or more of cesium carbonate, cesium bicarbonate, cesium stearate, cesium acetate, cesium nitrate, cesium chloride, cesium bromide, cesium iodide, cesium phosphate, cesium oxalate, cesium permanganate, cesium chromate, cesium dichromate, cesium borate, cesium silicate, cesium tungstate, cesium molybdate, cesium vanadate, cesium fluoride, cesium sulfite, cesium dihydrogen phosphate, cesium dihydrogen phosphate, cesium formate, cesium oleate, cesium propionate, cesium butyrate, cesium citrate, cesium sulfate, cesium tartrate, cesium gluconate and cesium salicylate; the organic ligand is one or more of octanoic acid, oleic acid, stearic acid, capric acid and trioctylphosphine oxide. The non-coordinating solvent is one or more combinations of octadecene, octane, and dodecane. The specific temperature is 60-120°C; the stirring time is 30-150 minutes; the stirring speed is 200rpm-500rpm. The concentration of the precursor solution A is 0.008-0.675g / mL.

[0022] Further, in step S2, the lead source is one or more of lead acetate, lead fluoride, lead cation, lead stearate, lead carbonate, lead nitrate, lead bromide, lead iodide, lead molybdate, lead chloride, lead arsenate, lead tungstate, lead vanadate, lead titanate, lead silicate, lead borate, lead laurate, lead myristate, lead palmitate, lead stearate, lead maleate, lead fumarate, lead tartrate, and lead citrate; the halogen source is one or more of hydrohalic acid, hydrobromic acid, and octadecyl dimethyl ammonium halide; the non-coordinating solvent is one or more of octadecene, octane, and dodecane; the inert gas used in the reaction is nitrogen or argon; the organic anion ligand It is one or more of oleic acid, stearic acid, oxalic acid, mercaptopropionic acid, dodecanethiol, thioglycolic acid, undecylenic acid, octanoic acid, trioctylphosphine oxide; the organic cationic ligand can be but not limited to one or more of oleylamine, dodecylamine, hexadecylamine, trioctylamine, tributylamine, octylamine; the set temperature is 40-60°C, the vacuum degree is 0.003-0.5MPa, the reaction time is 0.8-2.3 hours, the temperature is raised to 80-160°C after the inert gas is introduced, and the reaction is carried out for 0.5-1 hour; after adding the organic anionic ligand and the organic cationic ligand, the temperature is heated to 170-200°C and stirred for 0.5-1 hour. The concentration of the precursor solution B is 0.002-0.873g / mL.

[0023] Furthermore, in step S3, the volume ratio of precursor solution A to precursor solution B is 0.05-2.4:1; precursor solution A is heated to 30-135°C, precursor solution B is heated to 40-180°C, and the temperature of precursor solution B is greater than that of precursor solution B, and the temperature of precursor solution A and precursor solution B when mixed is 50-120°C; the reaction time is 0.5-120 hours; the polar solvent is one or more of pure water, isopropanol, ethanol, methanol, propanol, ethyl acetate, acetone, acetonitrile, dimethyl sulfoxide, dimethylformamide, glycerol, pyridine, tetrahydrofuran, methyl formate, and butanone; the volume ratio of the polar solvent to precursor solution A is 0.12-1.53:1.

[0024] Furthermore, in step S4, the reaction time of the precursor solution C in the oven is 0.5-96 hours, and the reaction temperature is 55-160°C; the relationship between the reaction time, reaction temperature, and the concentration of the anion and cation precursor solutions and the length and width of the nanowires: the higher the temperature and the longer the time, the longer the nanowires, and the greater the concentration of the anion and cation precursor solutions, the thicker the radius of the nanowires; the larger the halogen atoms, the more red-shifted the spectrum of the nanowires; the cooling method can be but is not limited to an ice water bath or liquid nitrogen.

[0025] Further, in step S5, the volume ratio of the anti-solvent to the solvent is 0.2-2:1, the solvent is one of toluene, n-hexane, cyclohexane, benzene, and octane, the anti-solvent is one of methyl acetate, isopropanol, ethyl acetate, ethanol, and acetone, and the concentration of the perovskite nanowires is 12.6-74.5 mg / mL; the rotation speed is 800-10000 rpm for each centrifugation, and the centrifugation time is 1-30 min.

[0026] Compared with the prior art, this patent application has the following beneficial effects:

[0027] Compared with perovskite quantum dots, ultra-long perovskite nanowires perform better in carrier transport. Due to its one-dimensional long-range structure, charges can be transported more efficiently and stably along the axis of the nanowire, reducing the probability of charge recombination, thereby significantly improving the performance of electronic devices. Secondly, ultra-long perovskite nanowires have better stability. Compared with perovskite quantum dots, it is less prone to degradation and performance degradation in the face of adverse environmental factors such as humidity, oxygen, temperature changes and light, and can maintain a good working state for a long time. Furthermore, ultra-long perovskite nanowires have higher optical absorption efficiency. Its longer structure can increase the absorption path of light, so that it can capture light energy more effectively, which is of great significance for the performance improvement of optoelectronic devices such as solar cells. In addition, ultra-long perovskite nanowires also have advantages in flexibility. It can better adapt to deformations such as bending and stretching, which provides more favorable conditions for the development of flexible and wearable optoelectronic devices. For example, in photodetectors, ultra-long perovskite nanowires can achieve faster and more sensitive light response with their excellent carrier transport and optical absorption properties. In the field of flexible displays, its good flexibility can meet the needs of various complex application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A low-magnification transmission electron microscope morphology image of an ultra-long nanowire obtained in a method for preparing an ultra-long perovskite nanowire in an air environment according to the present invention;

[0029] Figure 2 An enlarged transmission electron microscope morphology image of an ultra-long nanowire obtained in a method for preparing an ultra-long perovskite nanowire in an air environment according to the present invention;

[0030] Figure 3 A high-resolution transmission electron microscope morphology image of an ultra-long nanowire obtained in a method for preparing an ultra-long perovskite nanowire in an air environment according to the present invention;

[0031] Figure 4 A fluorescence image of ultra-long nanowires obtained in a method for preparing ultra-long perovskite nanowires in an air environment according to the present invention;

[0032] Figure 5 is an absorption graph of ultra-long nanowires obtained in a method for preparing ultra-long perovskite nanowires in an air environment according to the present invention;

[0033] Figure 6 This is an energy spectrum diagram of ultra-long nanowires obtained in a method for preparing ultra-long perovskite nanowires in an air environment according to the present invention. DETAILED DESCRIPTION

[0034] The present invention will be further described below through specific embodiments in conjunction with the accompanying drawings.

[0035] Example 1

[0036] A method for preparing ultra-long perovskite nanowires in an air environment comprises the following steps:

[0037] S1: Prepare precursor solution A

[0038] 2.4 mmol of cesium carbonate, 2.25 mL of oleic acid, 1 mL of octanoic acid and octadecene were fully mixed, stirred at 60° C. for 30 min at a stirring speed of 200 rpm to obtain a clear and transparent cesium precursor solution with a concentration of 0.033 g / mL.

[0039] S2: Prepare precursor solution B

[0040] 1 mmol of lead bromide, 1 mL of hydrobromic acid and 10 mL of octadecene were fully mixed, and the vacuum was evacuated for 30 minutes to obtain an anhydrous and oxygen-free environment with a vacuum degree of 0.02 MPa. The reaction temperature was 40°C and the reaction time was 50 minutes. Then nitrogen was introduced, and the temperature was raised to 80°C for 30 minutes. Subsequently, 1 mL of oleic acid, 0.5 mL of octanoic acid, 0.7 mL of octylamine and 1 mL of oleylamine were added respectively, and the mixture was heated to 170°C and stirred for 30 minutes to obtain a clear and transparent lead bromide precursor solution of 0.026 g / mL.

[0041] S3: Preparation of precursor solution C

[0042] The cesium precursor solution and the lead bromide precursor solution were preheated to 60 degrees and 110 degrees respectively, and then 2 mL of the cesium precursor solution was added to 10 mL of the lead bromide precursor solution, and the reaction was carried out for 30 minutes, and then 0.3 mL of ethanol was added, and then the solution was quickly cooled to room temperature; precursor solution C was obtained.

[0043] S4: preparing a raw solution of initial ultra-long perovskite nanowires;

[0044] The precursor solution C was placed in a reaction kettle, and then placed in an oven, and reacted at a temperature of 100° C. for 24 hours, and then the solution was quickly cooled to room temperature to obtain the original solution of ultra-long perovskite nanowires.

[0045] S5: Obtain clean ultra-long perovskite nanowires.

[0046] Take 5 mL of the solution prepared by S4, add 10 mL of ethyl acetate into it, and centrifuge at a speed of 8000 rpm for 4 minutes. Then, add the obtained precipitate into toluene for dispersion again, repeat the above centrifugation steps several times, and finally successfully obtain clean ultra-long perovskite nanowires.

[0047] The TEM characterization of the ultra-long CsPbBr3 nanowires revealed that the length of the nanowires exceeded 3 microns, but the diameter was only 5-10 nm, indicating that the aspect ratio of the nanowires exceeded 300 ( Figure 1 ,2). Subsequently, high-resolution TEM characterization of the nanowires revealed that the lattice parameter of the nanowires was 0.42nm ( Figure 3 ), corresponding to the (110) crystal plane of perovskite, indicating that the CsPbBr3 nanowires are in cubic phase. Fluorescence spectroscopy characterization revealed that the fluorescence peak of the CsPbBr3 nanowires is at 480nm, with a half-peak width of 50nm ( Figure 4 ), demonstrating that CsPbBr3 nanowires can be used as excellent lighting or display materials, with an absorption peak at 447nm and a Stokes shift of 33nm ( Figure 5 ). Through the energy spectrum characterization of CsPbBr3 nanowires, it was found that the nanowires contain Cs, Pb, and Br elements, and the element ratio is basically equal to 1:1:3 ( Figure 6 ), indicating that the synthesized nanowires indeed belong to CsPbBr3.

[0048] Example 2

[0049] A method for preparing ultra-long perovskite nanowires in an air environment comprises the following steps:

[0050] S1: Prepare precursor solution A

[0051] 1.7 mmol cesium acetate, 1 mmol cesium sulfate, 0.3 mL oleic acid, 1.2 mL octanoic acid and octadecene were fully mixed, stirred at 85° C. for 90 min at a stirring speed of 300 rpm to obtain a clear and transparent cesium precursor solution with a concentration of 0.038 g / mL.

[0052] S2: Prepare precursor solution B

[0053] 1.1 mmol of lead iodide, 1 mL of hydrobromic acid and 10 mL of octadecene were fully mixed, and the vacuum was evacuated for 30 minutes to obtain an anhydrous and oxygen-free environment with a vacuum degree of 0.1 MPa. The reaction temperature was 50°C and the reaction time was 80 minutes. Then nitrogen was introduced, and the temperature was raised to 120°C for 45 minutes. Subsequently, 1.55 mL of oleic acid, 0.45 mL of octanoic acid, 0.7 mL of octylamine and 1.3 mL of oleylamine were added respectively, and the mixture was heated to 180°C and stirred for 45 minutes to obtain a clear and transparent 0.036 g / mL lead bromide precursor solution.

[0054] S3: Preparation of precursor solution C

[0055] The cesium precursor solution and the lead iodide precursor solution were preheated to 80° C. and 130° C., respectively. Then, 2 mL of the cesium precursor solution was added to 10 mL of the lead iodide precursor solution, and the reaction was carried out for 60 min. Then, 0.5 mL of ethyl acetate was added, and the solution was quickly cooled to room temperature. Precursor solution C was obtained.

[0056] S4: preparing an initial stock solution of nanowires;

[0057] The precursor solution C was placed in a reaction kettle, and then placed in an oven, and reacted at a temperature of 120° C. for 48 hours, and then the solution was quickly cooled to room temperature to obtain the original solution of ultra-long nanowires.

[0058] S5: Obtain clean hollow-structured perovskite ultra-long nanowires.

[0059] Take 5 mL of the solution prepared by S4, add 10 mL of ethyl acetate into it, and centrifuge at a speed of 7000 rpm for 5 minutes. Then, add the obtained precipitate into toluene for dispersion again, repeat the above centrifugation steps several times, and finally successfully obtain clean ultra-long perovskite nanowires.

[0060] Example 3

[0061] A method for preparing ultra-long perovskite nanowires in an air environment comprises the following steps:

[0062] S1: Prepare precursor solution A

[0063] 1.7 mmol cesium acetate, 1 mmol cesium sulfate, 0.3 mL oleic acid, 1.2 mL octanoic acid and octadecene were fully mixed, stirred for 150 min at 120° C. with a stirring speed of 500 rpm to obtain a clear and transparent cesium precursor solution with a concentration of 0.038 g / mL.

[0064] S2: Prepare precursor solution B

[0065] 0.5mmol lead bromide, 0.55mmol lead iodide, 1mL hydrobromic acid and 10mL octadecene were fully mixed, evacuated for 30min, and an anhydrous and oxygen-free environment with a vacuum degree of 0.15MPa was obtained. The reaction temperature was 60°C and the reaction time was 120min. Then nitrogen was introduced, and the temperature was raised to 160°C for 60min. Then 1.55mL oleic acid, 0.5mL octanoic acid, 0.7mL octylamine and 1.2mL oleylamine were added respectively, heated to 200°C, and stirred for 60min to obtain a clear and transparent 0.030g / mL lead bromide precursor solution.

[0066] S3: Preparation of precursor solution C

[0067] The cesium precursor solution and the lead bromide precursor solution were preheated to 100° C. and 150° C., respectively. Then, 2 mL of the cesium precursor solution was added to 10 mL of the lead bromide precursor solution, and the reaction was carried out for 30 min. Then, 0.8 mL of methanol was added, and the solution was quickly cooled to room temperature. Precursor solution C was obtained.

[0068] S4: preparing the original solution of the initial ultra-long perovskite nanowires;

[0069] The precursor solution C was placed in a reaction kettle, and then placed in an oven, and reacted at a temperature of 160° C. for 72 hours, and then the solution was quickly cooled to room temperature to obtain the original solution of ultra-long nanowires.

[0070] S5: Obtain clean ultra-long perovskite nanowires.

[0071] Take 5 mL of the solution prepared by S4, add 10 mL of ethyl acetate into it, and centrifuge at a speed of 6000 rpm for 6 minutes. Then, add the obtained precipitate into toluene for dispersion again, repeat the above centrifugation steps several times, and finally successfully obtain clean ultra-long perovskite nanowires.

[0072] Note: In actual operation, temperature control needs to be extremely precise. Even a slight deviation may lead to unsatisfactory reaction results. For example, the amount of various reagents added must be strictly in accordance with the predetermined amount. If there is a slight mistake, the expected product may not be obtained.

Claims

1. A method for preparing ultra-long perovskite nanowires in an air environment, characterized in that: The specific steps are as follows: S1: prepare precursor solution A; S2: prepare precursor solution B; S3: preparing precursor solution C; S4: preparing the original solution of the initial ultra-long perovskite nanowires; S5: Obtain clean perovskite ultra-long nanowires.

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