Method for in-situ preparation of perovskite quantum dot polymer composite film
The method of preparing perovskite quantum dot polymer composite films in situ has solved the problems of stability and photoelectric performance of perovskite quantum dots, and achieved the effects of simplifying the process, reducing costs and improving photoelectric performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-27
- Publication Date
- 2026-04-14
AI Technical Summary
Existing technologies cannot effectively solve the stability problem of perovskite quantum dots, and there are problems such as complex processes, high costs, easy agglomeration, and decreased photoluminescence quantum yield, making it impossible to achieve a balance between their excellent optoelectronic properties and practical applications.
A method for preparing perovskite quantum dot polymer composite films in situ was adopted. The perovskite quantum dot precursor and the polymer were mixed in a solvent and then spin-coated into a film. The precursor was then dried to achieve in-situ crystallization in the polymer matrix, thus preparing the perovskite quantum dot polymer composite film.
The preparation process was simplified, production costs were reduced, and the polymer matrix exhibited good compatibility with perovskite quantum dots, which inhibited agglomeration, improved photoluminescence and water resistance, and enhanced photostability, thus achieving a good balance between the excellent optoelectronic properties of perovskite quantum dots and their practical applications.
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Figure CN121852048A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of optoelectronic materials technology, and in particular to a method for in-situ preparation of perovskite quantum dot polymer composite films. Background Technology
[0002] Perovskite quantum dots (PQDs), as a promising new type of semiconductor nanomaterial, have demonstrated irreplaceable application value in many cutting-edge fields such as photoelectric conversion, high-definition display, and solid-state lighting due to their outstanding optical and electrical properties, such as high photoluminescence quantum yield, tunable emission spectrum, narrow excitation spectrum and excellent color purity. They have become a research focus in the field of nanomaterials.
[0003] However, the practical application and large-scale promotion of PQDs are limited by their inherent stability defects. On the one hand, PQDs exhibit typical ionic crystal characteristics, with weak ionic bonding within the crystal lattice; on the other hand, their surfaces commonly contain dangling bonds, uncoordinated metal ions, and oxidation states, making them extremely sensitive to environmental factors such as water, oxygen, light, and temperature changes. When exposed to these environments, PQDs readily undergo surface chemical reactions, which not only exacerbate existing defects but also induce new surface defects, ultimately leading to crystal structure collapse, quantum dot degradation, and a sharp decline in luminescent performance.
[0004] To address the stability challenge of quantum quantum dots (PQDs), researchers have conducted extensive research, with surface ligand engineering being one of the most widely used strategies. This strategy enhances the binding strength between ligands and PQD surfaces by introducing ligands with higher affinity, thereby isolating them from external environmental interference to some extent. However, practical experience shows that this method has significant limitations: firstly, the binding between ligands and PQDs is mostly a weak interaction, and ligand detachment easily occurs during long-term use, resulting in a loss of protective effect; secondly, during ligand washing and purification, functional ligands on the quantum dot surface are easily removed simultaneously, leading to halogen vacancies and uncoordinated Pb. 2+ The emergence of new defects exacerbates the risk of ion migration; thirdly, it can only improve the surface state of quantum dots themselves, but cannot fundamentally isolate the continuous erosion of water and oxygen, and the stability is still difficult to meet the needs of actual use.
[0005] Besides surface modification, the traditional "synthesis-then-encapsulation" approach has also been widely explored. This involves first preparing PQDs using processes such as hot-injection molding, and then encapsulating them with polymers or inorganic materials. However, this separate process has several drawbacks: First, the purification and dispersion steps after PQD synthesis are complex, significantly increasing preparation costs. Second, PQDs are small in size and have high surface activity, making them prone to aggregation during post-processing and encapsulation, disrupting dispersion uniformity. Third, encapsulation operations can easily cause mechanical damage to PQDs or introduce impurities, leading to a decrease in photoluminescence quantum yield (PLQY) and secondary damage. Fourth, interfacial gaps easily exist between the encapsulation layer and the PQDs, failing to form a dense protective layer, allowing water and oxygen to permeate and cause degradation.
[0006] In summary, existing technologies, whether surface ligand engineering or the "synthesis-then-encapsulation" approach, have failed to effectively address the technical challenges of process complexity, insufficient stability, and high cost, thus failing to achieve a balance between the superior optoelectronic performance of PQDs and their practical application feasibility. Against this backdrop, developing a fabrication strategy that can circumvent these shortcomings from the outset is urgently needed. Summary of the Invention
[0007] The purpose of this invention is to provide a method for in-situ preparation of perovskite quantum dot polymer composite films to solve the problems existing in the prior art.
[0008] To achieve the above objectives, the present invention provides the following solution: This invention provides a method for in-situ preparation of perovskite quantum dot polymer composite films, comprising the following steps: (1) Dissolution of precursor and polymer: Methylamine halide (MAX, X=Cl, Br, I) and lead halide (PbX2, X=Cl, Br, I) are mixed in a solvent as PQDs precursors. The polymer is added to the obtained precursor solution to obtain a precursor-polymer mixed solution. (2) Spin-coating the solution: spin-coating the precursor-polymer mixture into a film, drying it, removing the solvent, and realizing the in-situ crystallization of the precursor in the polymer matrix to obtain the perovskite quantum dot polymer composite film in situ. The polymer is one of polyvinyl butyral (PVB), styrene-acrylonitrile copolymer (SAN), and polyvinyl acetate (PVAc).
[0009] Furthermore, the mass fraction (referred to as CN content) of acrylonitrile copolymer units in the styrene-acrylonitrile copolymer is 15%~40%.
[0010] Furthermore, the molar ratio of methylamine halide to lead halide is 1:1 to 7:1; preferably 3:1 to 5:1.
[0011] Furthermore, the concentration of the precursor in the precursor-polymer mixed solution is 1 mg / ml to 20 mg / ml. Preferably, it is 3 to 12 mg / ml.
[0012] Furthermore, the polymer used has a solid content of 15-40 wt%; preferably 20-30%.
[0013] Furthermore, the spin coating speed for the spin coating film is 500~4000 rpm and the acceleration is 100~500 rpm / s; preferably, the spin coating speed is 100~3000 rpm and the acceleration is 150~300 rpm / s.
[0014] Furthermore, the spin-coated film is dried on a hot table or under vacuum.
[0015] This invention provides a perovskite quantum dot polymer composite film, which is prepared by the above method.
[0016] The perovskite quantum dot polymer composite film of the present invention contains MAPbX3 perovskite quantum dots, and the photoluminescence quantum yield (PLQY) is ≥35%.
[0017] This invention also provides an application of perovskite quantum dot polymer composite film in the fields of photoelectric conversion, high-definition display, or solid-state lighting.
[0018] The present invention discloses the following technical effects: This invention employs an in-situ synthesis strategy, in which perovskite quantum dot precursors are mixed with polymers in a solvent and then spin-coated into a film. The precursors are then dried to achieve in-situ crystallization in the polymer matrix, eliminating the need for complex post-processing steps, simplifying the preparation process, and reducing production costs.
[0019] The polymer matrix of this invention has good compatibility with PQDs, which can effectively inhibit the aggregation of PQDs and ensure their uniform dispersion in the matrix. At the same time, the electron-rich groups of the polymer can passivate the surface defects of PQDs and improve the crystal quality.
[0020] The PQDs polymer composite film prepared by the method of this invention exhibits excellent photoluminescence properties, and the polymer matrix forms a dense protective barrier, significantly enhancing the water resistance and photostability of the PQDs. This effectively resists the erosion of environmental factors such as water, oxygen, and light, preventing crystal structure collapse and luminescence performance degradation. Furthermore, by adjusting the polymer type, precursor ratio, and process parameters, the performance of the composite film can be flexibly optimized, making it promising for applications in photoelectric conversion, high-definition displays, and lighting, achieving a good balance between the excellent photoelectric properties of PQDs and practical application feasibility. Attached Figure Description
[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0022] Figure 1 This is a schematic diagram of the process for in-situ preparation of polymer-PQDs composite films according to the present invention. Detailed Implementation
[0023] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.
[0024] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.
[0025] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.
[0026] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This specification and embodiments are merely exemplary.
[0027] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.
[0028] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.
[0029] Figure 1This is a schematic diagram of the process for in-situ preparation of PQDs polymer films using the spin coating method of the present invention.
[0030] The synthesis of MAPbX3 perovskite quantum dots described in this invention uses methylamine bromide (MAX, X = Cl, Br, I) and lead halide (PbX2, X = Cl, Br, I) as precursor raw materials. Chlorine (Cl), bromine (Br), and iodine (I) belong to the same group of halogens, and their compounds have similar properties. For ease of description, the following examples all use methylamine bromide (MABr) and lead bromide (PbBr2) as examples.
[0031] Example 1 This embodiment provides a method for in-situ preparation of PQDs polymer films using spin coating, including the following steps: (1) Dissolution of precursors and polymers: Using 10 mL of N,N-dimethylformamide (DMF) as a solvent, 23.90 mg of methylamine bromide (MABr) and 26.10 mg of lead bromide (PbBr2) (precursor concentration 5 mg / mL, molar ratio 3:1) were added as PQDs precursors. The mixture was stirred thoroughly and sonicated until the precursors were completely dissolved to form a homogeneous and transparent precursor solution. Add 3.15g of SAN resin (CN content 25%) to the above precursor solution and stir thoroughly until the polymer is completely dissolved to obtain a homogeneous precursor-polymer mixed solution; Finally, ultrasonic treatment was used to remove air bubbles from the solution, preventing defects from occurring during subsequent film formation. The polymer had a solid content of 25 wt% and was dried at 60°C for 6 hours to thoroughly remove moisture and impurities.
[0032] (2) Solution spin coating: The film formation operation was performed using an EZ6-S spin coater (Jiangsu Leibo Scientific Instruments Co., Ltd.): A clean spin-coating substrate was placed inside the spin coater and secured firmly with a suction cup; the spin-coating process parameters were set as follows: spin speed 1000 rpm, acceleration 300 rpm / s, and spin time 20 s; the above-mentioned precursor-polymer mixed solution after degassing was uniformly dropped onto the surface of the spin-coating substrate, and the spin coater was started. Under the action of centrifugal force, the solution spread evenly on the substrate, forming a wet film; at this time, the film was colorless and transparent, and perovskite crystals had not yet precipitated.
[0033] (3) Drying and film formation: After spin coating, the substrate carrying the wet film is quickly removed and transferred to a heating stage at 60°C and kept dry for 4 hours. During the drying process, the solvent DMF gradually evaporates, and the precursor MABr and PbBr2 gradually undergo in-situ crystallization reaction from the edge to the center of the substrate in the polymer matrix to generate PQDs; finally, PQDs-polymer composite film is obtained.
[0034] Example 2 This embodiment provides a method for in-situ preparation of PQDs polymer films using spin coating, including the following steps: (1) Dissolution of precursors and polymers: Using 10 mL of DMF as solvent, 30.20 mg of MABr and 19.80 mg of PbBr2 (precursor concentration 5 mg / mL, molar ratio 5:1) were added as PQDs precursors. The mixture was stirred thoroughly and sonicated until the precursors were completely dissolved to form a homogeneous and transparent precursor solution. Add 3.15g of SAN resin (CN content 25%) to the above precursor solution and stir thoroughly until the polymer is completely dissolved to obtain a homogeneous precursor-polymer mixed solution; Finally, ultrasonic treatment is used to remove air bubbles from the solution to avoid defects in the subsequent film formation process. The polymer has a solid content of 25 wt% and needs to be dried at 60°C for 6 hours beforehand to thoroughly remove moisture and impurities.
[0035] Steps (2)-(3) are the same as in Example 1.
[0036] Example 3 This embodiment provides a method for in-situ preparation of PQDs polymer films using spin coating, including the following steps: (1) Dissolution of precursors and polymers: Using 10 mL of DMF as solvent, 30.20 mg of MABr and 19.80 mg of PbBr2 (precursor concentration 5 mg / mL, molar ratio 5:1) were added as PQDs precursors. The mixture was stirred thoroughly and sonicated until the precursors were completely dissolved to form a homogeneous and transparent precursor solution. Add 3.15g of SAN resin (CN content 33%) to the above precursor solution and stir thoroughly until the polymer is completely dissolved to obtain a homogeneous precursor-polymer mixed solution.
[0037] Finally, ultrasonic treatment is used to remove air bubbles from the solution to avoid defects in the subsequent film formation process. The polymer has a solid content of 25 wt% and needs to be dried at 60°C for 6 hours beforehand to thoroughly remove moisture and impurities.
[0038] Steps (2)-(3) are the same as in Example 1.
[0039] Example 4 This embodiment provides a method for in-situ preparation of PQDs polymer films using spin coating, including the following steps: (1) Dissolution of precursors and polymers: Using 10 mL of DMF as solvent, 27.48 mg of MABr and 22.52 mg of PbBr2 (precursor concentration 5 mg / mL, molar ratio 4:1) were added as PQDs precursors. The mixture was stirred thoroughly and sonicated until the precursors were completely dissolved to form a homogeneous and transparent precursor solution. Add 3.15g of SAN resin (CN content 25%) to the above precursor solution and stir thoroughly until the polymer is completely dissolved to obtain a homogeneous precursor-polymer mixed solution; Finally, ultrasonic treatment is used to remove air bubbles from the solution to avoid defects in the subsequent film formation process. The polymer has a solid content of 25 wt% and needs to be dried at 60°C for 6 hours beforehand to thoroughly remove moisture and impurities.
[0040] Steps (2)-(3) are the same as in Example 1.
[0041] Example 5 (1) Dissolution of precursors and polymers: Using 10 mL of LDMF as a solvent, 38.47 mg of MABr and 31.53 mg of PbBr2 (precursor concentration 7 mg / mL, molar ratio 4:1) were added as PQDs precursors. The mixture was stirred thoroughly and sonicated until the precursors were completely dissolved to form a homogeneous and transparent precursor solution. Add 3.15g of SAN resin (CN content 25%) to the above precursor solution and stir thoroughly until the polymer is completely dissolved to obtain a homogeneous precursor-polymer mixed solution; Finally, ultrasonic treatment is used to remove air bubbles from the solution to avoid defects in the subsequent film formation process. The polymer has a solid content of 25 wt% and needs to be dried at 60°C for 6 hours beforehand to thoroughly remove moisture and impurities.
[0042] Steps (2)-(3) are the same as in Example 1.
[0043] Example 6 This embodiment provides a method for in-situ preparation of PQDs polymer films using spin coating, including the following steps: (1) Dissolution of precursors and polymers: Using 10 mL of LDMF as a solvent, 27.48 mg of MABr and 22.52 mg of PbBr2 (precursor concentration 5 mg / mL, molar ratio 4:1) were added as PQDs precursors. The mixture was stirred thoroughly and sonicated until the precursors were completely dissolved to form a homogeneous and transparent precursor solution. Add 3.15g of PVB resin to the above precursor solution and stir thoroughly until the polymer is completely dissolved to obtain a homogeneous precursor-polymer mixed solution. Finally, ultrasonic treatment is used to remove air bubbles from the solution to avoid defects in the subsequent film formation process. The polymer has a solid content of 25 wt% and needs to be dried at 60°C for 6 hours beforehand to thoroughly remove moisture and impurities.
[0044] Steps (2)-(3) are the same as in Example 1.
[0045] Example 7 This embodiment provides a method for in-situ preparation of PQDs polymer films using spin coating, including the following steps: (1) Dissolution of precursors and polymers: Using 10 mL of LDMMF as a solvent, 23.90 mg of MABr and 26.10 mg of PbBr2 (precursor concentration 5 mg / mL, molar ratio 3:1) were added as PQDs precursors, respectively. The mixture was stirred thoroughly and sonicated until the precursors were completely dissolved to form a homogeneous and transparent precursor solution. Add 3.15g of PVAc resin to the above precursor solution and stir thoroughly until the polymer is completely dissolved to obtain a homogeneous precursor-polymer mixed solution. Finally, ultrasonic treatment is used to remove air bubbles from the solution to avoid defects in the subsequent film formation process. The polymer has a solid content of 25 wt% and needs to be dried at 60°C for 6 hours beforehand to thoroughly remove moisture and impurities.
[0046] Steps (2)-(3) are the same as in Example 1.
[0047] Comparative Example 1 The only difference from Example 1 is that the polymer is replaced with an equal mass of PMMA.
[0048] Comparative Example 2 The only difference from Example 1 is that the polymer is replaced with an equal mass of SMMA.
[0049] Comparative Example 3 This comparative example provides a method for preparing antisolvents for PQDs, the steps of which are as follows: 23.90 mg MABr and 26.10 mg PbBr2 were dissolved in 5 ml of DMF solvent to form a precursor solution. Then, 0.2 ml of the precursor solution was added to a vigorously stirred toluene solution, and PQDs precipitated rapidly to obtain a pure PQDs solution.
[0050] The photoluminescence quantum yield test results of the thin film samples prepared in the above embodiments and comparative examples (testing equipment: FLS1000 steady-state / transient fluorescence spectrometer from Edinburgh, UK. Excitation wavelength 378 nm, emission spectrum scanning range 400-700 nm) are shown in Table 1.
[0051] Table 1 Water resistance test: The water resistance of the PQDs materials prepared in Examples 3, 6, and Comparative Example 3 was characterized. To simulate a water immersion environment, a small amount of water was added to a pure PQDs solution to observe the performance changes of the PQDs. The SAN33-PQDs film (Example 3) and PVB film (Example 6) prepared in situ were completely immersed in water (at 25°C). After immersion for a certain period of time, they were removed and subjected to fluorescence spectroscopy tests, and their light intensity retention rate was calculated. The results are shown in Table 2.
[0052] Table 2 Stability test under strong blue light irradiation: The PQDs materials prepared in Examples 3, 6, and Comparative Example 3 were subjected to optical testing at a wavelength of 450-455 nm and an optical power of 50 W / cm². 2 The sample was subjected to strong blue light irradiation at a temperature of 25℃ and a humidity of 50%RH. After irradiation for a certain period of time, the sample was removed and subjected to fluorescence spectroscopy testing. The results of fluorescence intensity retention are shown in Table 3.
[0053] Table 3 In summary, this invention generates PQDs in situ in a transparent polymer matrix via spin coating. By utilizing the low temperature of the preparation process and the combined effect of the electron-rich groups in the polymer on the passivation of quantum dot defects, efficient dispersion and performance optimization of quantum dots are achieved. Perovskite quantum dot materials with high quantum yield and excellent water resistance and photostability are obtained, providing a solution to the problems of complex and unstable traditional quantum dot synthesis processes.
[0054] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.
Claims
1. A method for in-situ preparation of perovskite quantum dot polymer composite films, characterized in that, Includes the following steps: (1) Dissolution of precursor and polymer: Methylamine halide and lead halide were mixed in a solvent as perovskite quantum dot precursors, and polymer was added to the obtained precursor solution to obtain a precursor-polymer mixed solution. (2) Spin-coating the solution: spin-coating the precursor-polymer mixture into a film, drying it, removing the solvent, and realizing the in-situ crystallization of the precursor in the polymer matrix to obtain the perovskite quantum dot polymer composite film in situ. The methylamine halide includes methylamine chloride, methylamine bromide, or methylamine iodine; the lead halide includes lead chloride, lead bromide, or lead iodide. The polymer is one of polyvinyl butyral, styrene-acrylonitrile copolymer, or polyvinyl acetate.
2. The method according to claim 1, characterized in that, The mass fraction of acrylonitrile copolymer units in the styrene-acrylonitrile copolymer is 15% to 40%.
3. The method according to claim 1, characterized in that, The molar ratio of methylamine halide to lead halide is 1:1 to 7:
1.
4. The method according to claim 3, characterized in that, The molar ratio of methylamine halide to lead halide is 3:1 to 5:
1.
5. The method according to claim 1, characterized in that, The concentration of the perovskite quantum dot precursor in the precursor-polymer mixed solution is 1 mg / ml to 20 mg / ml.
6. The method according to claim 5, characterized in that, The concentration of the perovskite quantum dot precursor in the precursor-polymer mixed solution is 3 mg / ml to 12 mg / ml.
7. The method according to claim 1, characterized in that, The spin coating speed for the spin coating film is 500-4000 rpm, and the acceleration is 100-500 rpm / s.
8. The method according to claim 7, characterized in that, The spin coating speed for the spin coating film is 1000-3000 rpm, and the acceleration is 150-300 rpm / s.
9. A perovskite quantum dot polymer composite film, characterized in that, It is prepared by the method according to any one of claims 1-8.
10. The application of the perovskite quantum dot polymer composite film as described in claim 9 in the fields of photoelectric conversion, high-definition display, or lighting.