A method for preparing a gradient alloy structure perovskite quantum dot nanofiber membrane based on microfluidic airflow spinning technology

Abstract

The application discloses a method for preparing a gradient alloy structure perovskite quantum dot nanofiber membrane based on a microfluidic airflow spinning technology. By adjusting the proportion of A-site cations in the perovskite precursor, the addition amount of ligands, and the type and proportion of halogens, a spinning solution is constructed by using polyacrylonitrile and an organic solvent, and Rb x Cs 1‑x PbX3 perovskite quantum dots are in-situ synthesized in the polymer nanofiber under the driving of controllable high-pressure airflow, and the controllable preparation of red, green and blue fluorescent perovskite nanofiber membranes is realized. The method is simple in operation, can realize rapid and macro preparation of the nanofiber membrane, and provides a new idea and method for the controllable synthesis of nanomaterials.

Description

TECHNICAL FIELD

[0001] The present application relates to a preparation method of in-situ synthesis of perovskite quantum dots in polymer fibers under controllable high-pressure gas flow environment using nanofibers as reactors, and belongs to the technical field of new nanomaterials and photoelectric material preparation. BACKGROUND

[0002] In recent years, a new generation of photoelectric conversion materials centered on perovskite quantum dots has attracted more and more attention and pursuit from domestic and foreign manufacturers and researchers due to its unique photoelectric properties, such as high quantum yield, coordinated emission, and narrow half-peak width. It is expected to become the most promising material in the fields of wide color gamut display, light-emitting diode, sensor, solar cell, and photocatalyst. Perovskite quantum dots (PQDs) mainly refer to a family of compounds with ABX3 structure. A site is usually a large cation with large ionic radius (such as methylamine ion, cesium ion, etc.), B site is a small metal cation with small ionic radius (such as Pb 2+ , Sn 4+ , etc.), and X site is a halogen anion. This kind of material has very high luminescent efficiency, and the luminescent wavelength can be precisely adjusted through component and size control. The tuning range can easily cover the entire visible light region, and the emission spectrum is narrow (12nm-40nm) with high color purity. The display device prepared from perovskite quantum dots has a wide color gamut (~140%) and even exceeds the commercialized OLED.

[0003] However, due to the inherent instability of perovskite quantum dots, such as the poor stability of perovskite quantum dot ionic crystals to light, heat, and moisture and oxygen in the air, which directly leads to a significant reduction in the service life of the device, becoming one of the problems that need to be urgently solved in this field. So far, it is still a great challenge to realize the continuous, large-scale, and stable production of perovskite quantum dots. During the synthesis and use process, the crystal structure of perovskite quantum dots is easily damaged, phase transition, and agglomeration, which leads to significant fluorescence quenching, and puts forward extremely strict conditions for the implementation scheme of perovskite quantum dot preparation. Therefore, in order to improve the stability of perovskite quantum dots, researchers have proposed various methods and carried out a large amount of effective preliminary work. The method of coating is usually used to improve the stability of perovskite quantum dots. The polymer can encapsulate the perovskite quantum dots, act as a barrier for perovskite quantum dots, and the dense polymer can enhance the stability of the water-sensitive material, resist the adverse environment from outside, and endow it with soft and easy-to-process properties. SUMMARY

[0004] The application provides a method for preparing a gradient alloy structure perovskite quantum dot nanofiber membrane based on a microfluidic airflow spinning technology. x Cs 1-x PbX3 perovskite quantum dots are selected and debugged, so that the perovskite quantum dots have a good practical application prospect.

[0005] The method for preparing the gradient alloy structure perovskite quantum dot nanofiber membrane based on the microfluidic airflow spinning technology comprises the following specific steps:

[0006] Step 1: a certain amount of organic solvent is measured in a glass beaker;

[0007] Step 2: different proportions of rubidium halide (RbX), cesium halide (CsX) and lead halide (PbX2) are respectively weighed in the beaker in step 1, and magnetic stirring is used until complete dissolution, so that a clear and transparent solution is obtained;

[0008] Step 3: an appropriate amount of organic ligand is added to the solution in step 2 and stirred until uniform;

[0009] Step 4: 1.5g of polyacrylonitrile (PAN) is weighed in the solution in step 3, and magnetic stirring is performed at room temperature for 6-8h, so that complete dissolution is realized, and a transparent and uniform precursor spinning solution is obtained;

[0010] Step 5: a series of gradient alloy structure perovskite quantum dot nanofiber membranes are synthesized by using the solution in step 4 as a spinning solution through a microfluidic airflow spinning machine.

[0011] Further, the organic solvent in step 1 is one or a mixture of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO), the addition amount of DMF is 7-10mL, and the addition amount of DMSO is 0-3mL;

[0012] Further, the molar amount of RbX and CsX in step 2 is 0.13-0.39mmol, and the molar amount of PbX2 is 0.26-0.52mmol, so that the molar ratio of monovalent cations to lead precursors in the whole precursor proportion is controlled to be 1:1;

[0013] Further, X in RbX, CsX and PbX2 in step 2 is I and Br, that is, different molar amounts of RbI, CsI, RbBr, CsBr, PbI2 and PbBr2 are weighed, and different proportions of Rb x Cs 1-x PbI3, RbxCs 1-x PbBr3, wherein x is 0.35-0.75;

[0014] Further, the organic ligand in step 3 is selected as n-octylamine or oleylamine, and the ligand is added in an amount of 0.05-0.30 mL;

[0015] Further, the gas flow pressure of the microfluidic gas flow spinning machine in step 5 is 0.4-0.8 MPa, and the flow rate of the injection pump is 0.2-0.4 mL / min.

[0016] The Rb x Cs 1-x PbX3 perovskite quantum dot precursor spinning solution.

[0017] The Rb x Cs 1-x The PbX3 perovskite quantum dot precursor spinning solution is used for the preparation of perovskite quantum dot nanofiber membranes based on a microfluidic gas flow spinning method.

[0018] Compared with the prior art, the present application has the following beneficial effects:

[0019] In the present application, by introducing Rb + The preparation of A-site doped gradient alloy structure perovskite quantum dots is realized, and the Rb x Cs 1-x In-situ synthesis of PbX3 perovskite quantum dot nanofiber membranes. The advantage of the microfluidic gas flow spinning method for preparing nanofiber membranes is that large-scale continuous preparation can be realized. By designing a program to control the movement of the spinning needle, uniform preparation of the nanofiber membrane in a large area can be realized. The prepared nanofiber is received on the nylon net of the collector, and finally the nanofiber membrane is obtained. In the spinning process, the volatilization of DMF is gradually controlled by gas flow, and the polyacrylonitrile and Rb x Cs 1-x PbX3 quantum dots are effectively separated, and the crystallization process of the PbX3 quantum dots is successfully prepared. Nanofiber membranes with multiple color fluorescence emission are successfully prepared, and the emission wavelength is 470-600 nm.

[0020] In the present application, Rb x Cs 1-x The PbX3 / PAN nanofiber membrane greatly improves the intrinsic stability of the perovskite quantum dots, and the perovskite quantum dots / polymer fibers prepared in batches form nanofiber membranes with high optical performance, which can be used for constructing high color gamut backlight displays. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 The Rb 0.5 Cs 0.5 PbI3 / PAN PQDs@red nanofiber membrane scanning electron microscope schematic diagram;

[0022] Figure 2Rb prepared for Case 1 0.5 Cs 0.5 SEM image of PbBr3 / PAN PQDs@green nanofiber membrane;

[0023] Figure 3 Rb prepared for Case 5 0.5 Cs 0.5 SEM image of PbBr3 / PAN PQDs@blue nanofiber membrane;

[0024] Figure 4 Rb prepared for Case 1 0.5 Cs 0.5 Fluorescence spectrum of PbI3 / PAN PQDs@red nanofiber membrane;

[0025] Figure 5 Rb prepared for Case 3 0.s Cs 0.5 Fluorescence spectrum of PbBr3 / PAN PQDs@green nanofiber membrane;

[0026] Figure 6 Rb prepared for Case 5 0.5 Cs 0.5 Fluorescence spectrum of PbBr3 / PAN PQDs@blue nanofiber membrane.

[0027] DETAILED DESCRIPTION

[0028] The technical solutions in the examples of the present application will be described clearly and completely below. Obviously, the described examples are only some of the examples of the present application, but not all the examples. Based on the examples in the present application, all the other examples obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0029] The following experimental methods and detection methods are all conventional methods unless otherwise specified. The following reagents and raw materials are commercially available unless otherwise specified.

[0030] Example 1

[0031] Step 1: 10 g of DMF was measured in a glass beaker;

[0032] Step 2: 0.26 mmol of RbI, 0.26 mmol of CsI and 0.52 mmol of PbI2 were weighed into the beaker of step 1 respectively, and were stirred by magnetic stirring until completely dissolved to obtain a clear and transparent solution;

[0033] Step 3: 0.19 mL of n-octylamine was added to the solution in step 2 and stirred until uniform;

[0034] Step 4: 1.5 g of polyacrylonitrile (PAN) was weighed into the solution in Step 3, and was magnetically stirred at room temperature for 6-8 h to completely dissolve, to obtain a transparent and uniform precursor spinning solution;

[0035] Step 5: A series of gradient alloy structure perovskite quantum dot nanofiber membranes were synthesized by using the solution in Step 4 as the spinning solution through a microfluidic airflow spinning machine.

[0036] The Rb 0.5 Cs 0.5 The PbI3 / PAN PQDs nanofiber membrane had a fluorescence emission peak position at 600.4 nm, and a half-peak width of 29 nm, and the Rb 0.5 Cs 0.5 The PbI3 / PAN PQDs nanofiber membrane had a fluorescence emission peak position at 600.4 nm, and a half-peak width of 29 nm, and the Rb

[0037] Example 2

[0038] Step 1: 10 g of DMF was measured in a glass beaker;

[0039] Step 2: 0.39 mmol of RbI, 0.13 mmol of Csl and 0.52 mmol of PbI2 were weighed into the beaker in Step 1, respectively, and were magnetically stirred until completely dissolved, to obtain a clear and transparent solution;

[0040] Step 3: 0.19 mL of n-octylamine was added to the solution in Step 2 and was stirred until uniform;

[0041] Step 4: 1.5 g of polyacrylonitrile (PAN) was weighed into the solution in Step 3, and was magnetically stirred at room temperature for 6-8 h to completely dissolve, to obtain a transparent and uniform precursor spinning solution;

[0042] Step 5: A series of gradient alloy structure perovskite quantum dot nanofiber membranes were synthesized by using the solution in Step 4 as the spinning solution through a microfluidic airflow spinning machine.

[0043] The Rb 0.75 Cs 0.25 The PbI3 / PAN PQDs nanofiber membrane had a fluorescence emission peak position at 600.4 nm, and a half-peak width of 29 nm, and the Rb 0.75 Cs 0.25 The PbI3 / PAN PQDs nanofiber membrane had a fluorescence emission peak position at 600.4 nm, and a half-peak width of 29 nm, and the Rb

[0044] Example 3

[0045] Step 1: weigh 10 g DMF in a glass beaker;

[0046] Step 2: weigh 0.26 mmol RbBr, 0.26 mmol CsBr and 0.52 mmol PbBr2 respectively in the beaker of step 1, stir by magnetic stirring until completely dissolved, to obtain a clear transparent solution;

[0047] Step 3: weigh 0.05 mL of oleylamine into the solution in step 2 and stir until uniform;

[0048] Step 4: weigh 1.5 g of polyacrylonitrile (PAN) into the solution in step 3, and stir by magnetic stirring at room temperature for 6-8 h, so that it is completely dissolved, to obtain a transparent and uniform precursor spinning solution;

[0049] Step 5: use the solution in step 4 as the spinning solution to synthesize a series of gradient alloy structure perovskite quantum dot nanofiber membranes by a microfluidic airflow spinning machine.

[0050] The Rb 0.5 Cs 0.5 The fluorescence emission peak position of the PbBr3 / PAN PQDs@green nanofiber membrane is at 514 nm, the half peak width is 25 nm, the Rb 0.5 Cs 0.5 The PbBr3 / PAN PQDs@green nanofiber membrane presents yellow under sunlight and green fluorescence under 365 nm ultraviolet light.

[0051] Example 4

[0052] Step 1: weigh 10 g DMF in a glass beaker;

[0053] Step 2: weigh 0.26 mmol RbBr, 0.26 mmol CsBr and 0.52 mmol PbBr2 respectively in the beaker of step 1, stir by magnetic stirring until completely dissolved, to obtain a clear transparent solution;

[0054] Step 3: weigh 0.27 mL of oleylamine into the solution in step 2 and stir until uniform;

[0055] Step 4: weigh 1.5 g of polyacrylonitrile (PAN) into the solution in step 3, and stir by magnetic stirring at room temperature for 6-8 h, so that it is completely dissolved, to obtain a transparent and uniform precursor spinning solution;

[0056] Step 5: use the solution in step 4 as the spinning solution to synthesize a series of gradient alloy structure perovskite quantum dot nanofiber membranes by a microfluidic airflow spinning machine.

[0057] The Rb 0.5 Cs0.5 The fluorescent emission peak position of the PbBr3 / PAN PQDs@blue nanofiber membrane is at 475.9 nm, and the half-peak width is 20 nm, Rb 0.5 Cs 0.5 The PbBr3 / PAN PQDs@blue nanofiber membrane presents a light yellow color under sunlight and a blue fluorescence under 365 nm ultraviolet light.

[0058] Example 5

[0059] Step 1: weigh 10 g of DMF in a glass beaker;

[0060] Step 2: weigh 0.18 mmol of RbBr, 0.34 mmol of CsBr and 0.52 mmol of PbBr2 respectively in the beaker of step 1, and use magnetic stirring to completely dissolve to obtain a clear and transparent solution;

[0061] Step 3: weigh 0.14 mL of n-octylamine and add it to the solution in step 2, and stir until uniform;

[0062] Step 4: weigh 1.5 g of polyacrylonitrile (PAN) in the solution in step 3, and magnetically stir at room temperature for 6-8 h to completely dissolve, to obtain a transparent and uniform precursor spinning solution;

[0063] Step 5: use the solution in step 4 as a spinning solution to synthesize a series of gradient alloy structure perovskite quantum dot nanofiber membranes by a microfluidic airflow spinning machine.

[0064] The Rb 0.35 Cs 0.65 The fluorescent emission peak position of the PbBr3 / PAN PQDs@blue nanofiber membrane is at 473.6 nm, and the half-peak width is 20 nm, Rb 0.35 Cs 0.65 The PbBr3 / PAN PQDs@blue nanofiber membrane presents a light yellow color under sunlight and a blue fluorescence under 365 nm ultraviolet light.

[0065] The sample in Example 1 was subjected to characterization tests, and the results showed that:

[0066] Please refer to Figure 1 , Figure 1 The Rb 0.5 Cs 0.5 The scanning electron microscope picture of the PbI3 / PAN PQDs@red nanofiber membrane sample can be seen from the figure, and the diameter of the nanofiber is uniformly distributed, and the average diameter is about 500 nm. The nanofiber surface is smooth, which indicates that the polymer matrix is rapidly solidified in the spinning process, and the Rb 0.5 Cs0.5 PbI3quantum dots.

[0067] See Figure 2 , Figure 2 Rb 0.5 Cs 0.5 PbBr3 / PAN PQDs@green nanofiber membrane sample. It can be seen from the figure that the diameters of the nanofibers are uniformly distributed, and the average diameter is about 500 nm. The surface of the nanofibers is smooth, indicating that the polymer matrix is rapidly solidified in the spinning process, and Rb 0.5 Cs 0.5 PbBr3quantum dots.

[0068] See Figure 3 , Figure 3 Rb 0.5 Cs 0.5 PbBr3 / PAN PQDs@blue nanofiber membrane sample. It can be seen from the figure that the diameters of the nanofibers are uniformly distributed, and the average diameter is about 500 nm. The surface of the nanofibers is smooth, indicating that the polymer matrix is rapidly solidified in the spinning process, and Rb 0.5 Cs 0.5 PbBr3quantum dots. See Figure 4 , Figure 4 Rb 0.5 Cs 0.5 PbI3 / PAN PQDs@red nanofiber membrane sample. Its fluorescence emission peak position is at 600.4 nm, and the half-peak width is 29 nm. The inset is Rb 0.5 Cs 0.5 PbI3 / PAN PQDs@red nanofiber membrane. It can be seen that the membrane under sunlight presents a light yellow color, and under ultraviolet light, it presents a red fluorescence.

[0069] See Figure 5 , Figure 5 Rb 0.5 Cs 0.5 PbBr3 / PAN PQDs@green nanofiber membrane sample. Its fluorescence emission peak position is at 514 nm, and the half-peak width is 25 nm. The inset is Rb 0.5 Cs 0.5 PbBr3 / PAN PQDs@green nanofiber membrane. It can be seen that the membrane under sunlight presents a yellow color, and under ultraviolet light, it presents a green fluorescence.

[0070] SeeFigure 6 , Figure 6 Rb 0.5 Cs 0.5 The fluorescence spectrum of the PbBr3 / PAN PQDs@blue nanofiber membrane sample is shown in Figure 8, and the fluorescence emission peak position is at 475.9 nm, and the half-peak width is 20 nm. The inset is Rb 0.5 Cs 0.5 The photos of the PbBr3 / PAN PQDs@blue nanofiber membrane under 365 nm ultraviolet light and sunlight, respectively, can be seen that the membrane under sunlight presents a light yellow color, and under ultraviolet light, it presents a blue fluorescence.

[0071] The above results show that the Rb x Cs 1-x The PbX3 / PAN PQDs nanofiber membrane realizes the regulation of the fluorescence color of perovskite quantum dots by regulating the proportion of the A-site cation in the precursor, the addition amount of the ligand, the type of halogen and the proportion of halogens, and successfully invents the controllable preparation of red, green and blue perovskite nanofiber membranes with gradient alloy structure.

[0072] Although the embodiments of the present application have been disclosed as above, it is not limited to the application listed in the specification and the embodiments, and can be fully applied to various fields suitable for the present application, and other modifications can be easily realized by those skilled in the art, and therefore the present application is not limited to specific details, without departing from the general concept defined by the claims and the equivalent scope.

Claims

1. A method for preparing a gradient alloy structure perovskite quantum dot nanofiber membrane based on a microfluidic airflow spinning method, characterized in that, The method comprises the following steps: Step 1: a certain amount of organic solvent is measured in a glass beaker; Step 2: Weigh 0.13-0.39 mmol of rubidium halide (RbX) and cesium halide (CsX) and 0.26-0.52 mmol of lead halide (PbX2) into the beaker from Step 1, control the molar ratio of monovalent cation (Rb + and Cs + ) to lead precursor (Pb 2+ ) to be 1:1, and use magnetic stirring to dissolve completely to obtain a clear and transparent solution; Step 3: an appropriate amount of organic ligand is added to the solution in step 2 and stirred until uniform; Step 4: 1.5 g of polyacrylonitrile (PAN) is weighed in the solution in step 3, and is magnetically stirred at room temperature for 6-8 h to completely dissolve, so as to obtain a transparent and uniform precursor spinning solution; Step 5: a series of gradient alloy structure perovskite quantum dot nanofiber membranes are synthesized by using the solution in step 4 as a spinning solution through a microfluidic airflow spinning machine.

2. The method of claim 1, wherein The organic solvent in step 1 is one or a mixture of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO), the addition amount of DMF is 7-10 mL, and the addition amount of DMSO is 0-3 mL.

3. The method of claim 1, wherein RbX, CsX, PbX2in step 2, X is I and Br, namely RbI, CsI, RbBr, CsBr, PbI2, PbBr2of different molar amounts are taken respectively to synthesize Rb x Cs 1- x PbI3, Rb x Cs 1-x PbBr3, wherein x is 0.35-0.

75.

4. The method of claim 1, wherein The organic ligand in step 3 is selected to be n-octylamine or oleylamine, and the addition amount of the ligand is 0.05-0.30 mL.

5. The method of claim 1, wherein The airflow pressure of the microfluidic airflow spinning machine in step 5 is 0.4-0.8 MPa, and the flow rate of the injection pump is 0.2-0.4 mL / min.

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