Calcium fluoride titanium ore quantum dot and preparation method thereof, light conversion adhesive film and preparation method thereof

Abstract

The invention belongs to the technical field of thin film material preparation, and particularly provides a calcium fluoride titanium ore quantum dot and a preparation method thereof, and a light conversion adhesive film and a preparation method thereof. The objective of the invention is to solve the problems of poor stability of perovskite quantum dots and poor stability of obtained perovskite quantum dot adhesive films in the prior art. Therefore, the calcium fluoride titanium ore quantum dot is CsPbX3: F, X is a halogen element and is selected from one of Cl, Br or I; the calcium fluoride titanium ore quantum dots are doped with fluorine elements, and F ions exist in crystal lattices of the CsPbX3 quantum dots in the mode that the F ions are combined with Pb ions to form PbF2. According to the calcium fluoride titanium ore quantum dot provided by the invention, a Pb-F bond with stable chemical property is formed in the perovskite quantum dot by using a fluorination strategy, and meanwhile, internal crystal lattices are stabilized and surface halide vacancies are passivated, so that the sensitivity of further chemical reaction between the Pb-F bond and infiltrated water molecules is reduced, and the stability of the Pb-F bond is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of thin film material preparation, and specifically provides a calcium fluoride perovskite quantum dot, a light conversion film and a preparation method thereof. Background Art

[0002] In the current photovoltaic power generation industry, P-type silicon power generation technology represented by emitter passivation and back contact (PERC) technology has gradually reached its efficiency limit (-24.5%). Compared with P-type silicon, N-type silicon has a longer carrier lifetime, and photovoltaic cells based on N-type silicon have a higher photoelectric conversion efficiency. Heterojunction (HJT or HIT) technology, as a representative technology for N-type silicon power generation, has a limit efficiency of up to 27.5%. However, the absorption of ultraviolet light by the TCO layer and amorphous silicon passivation layer results in a low responsivity of HJT cells to ultraviolet and short-wave irradiation, making its current lower than that of PERC cells.

[0003] Influenced by the long carrier lifetime of N-type silicon, HJT cells have a higher theoretical conversion efficiency than PERC cells. However, the absorption of ultraviolet light by the TCO layer and amorphous silicon passivation layer in HJT cells results in a smaller current. By converting ultraviolet light into visible light that can be efficiently utilized by HJT cells through fluorescence down-conversion technology, the spectral responsivity of the cells can be enhanced, and the photoelectric conversion efficiency of the cells can be further improved. As a fluorescence down-conversion material, perovskite quantum dots have advantages such as a wide absorption range, high PLQY, and continuously tunable luminescence. High-quality perovskite quantum dot films are the key factors for improving the photoelectric conversion efficiency of cells.

[0004] In the prior art, Huang Sheng et al. mixed the synthesized perovskite quantum dots and EVA and then spin-coated them on a crystalline silicon cell to prepare a fluorescence down-conversion layer, which increased the cell efficiency to 1.18%. However, the two-step synthesis and spin-coating method limit the application of this method. Meng Linghai et al. spin-coated a perovskite precursor dissolved in DMF and PAN on a crystalline silicon cell in situ to form a film, and the cell efficiency increased by 0.9%. However, this light conversion film is not compatible with the current market light conversion films (EVA, POE), which is not conducive to large-scale preparation. In addition, in the prior art when preparing perovskite thin films, some use a large amount of ligands, resulting in poor uniformity of the film and poor dispersion of perovskite quantum dots in the film, and problems such as easy agglomeration are likely to occur, resulting in poor transmittance of the perovskite thin film.

[0005] CN116693905A discloses a perovskite quantum dot film and a preparation method thereof. The preparation method includes mixing an A precursor, a B precursor, an X precursor with a matrix resin, and extruding to obtain the perovskite quantum dot film; or granulating the A precursor, the B precursor, the X precursor with the matrix resin to respectively obtain a masterbatch containing the A precursor, a masterbatch containing the B precursor, a masterbatch containing the X precursor, mixing the masterbatches, and extruding to obtain the perovskite quantum dot film, and defining the extrusion parameters. During the extrusion process, the precursors react to generate perovskite quantum dots, and the perovskite quantum dot film is obtained by in-situ growth in the film, developing a light conversion film for HJT cells. The light conversion film can convert ultraviolet and short-wavelength light with low battery responsivity into visible light under fluorescence, improving the short-circuit current of HJT.

[0006] However, perovskite quantum dots are prone to decomposition or structural degradation under external stimuli (environmental conditions such as light, moisture, oxygen, and high temperature). This is mainly due to the internal ion migration and the detachment of weakly bound ligands on the surface of perovskite quantum dots to form defects, resulting in unstable structures that are easily affected by environmental factors such as humidity, light, and temperature. The required storage environmental conditions are relatively harsh, which is not conducive to popularization. As a result, the stability of the prepared perovskite quantum dot film is also affected.

[0007] CN114621758A discloses a stable and highly luminescent all-inorganic fluorinated perovskite quantum dot and its preparation method and application. The method uses a cesium source, a lead source, a long-chain alkanoic acid, a long-chain organic amine, trioctylphosphine, octadecene, a halogen source, and a fluorine source as raw materials to obtain the all-inorganic fluorinated perovskite quantum dot through a high-temperature thermal injection method. The prepared all-inorganic fluorinated perovskite quantum dot has good dispersibility, uniformity, and repeatability. However, CsF formed after this fluorination treatment is prone to aggregation inside the quantum dot lattice, resulting in uneven fluorine distribution and unable to effectively passivate the entire quantum dot. In addition, F may detach from CsF and migrate to other positions inside the lattice, leading to unstable lattice structure and damaging the internal structure of the quantum dot. At the same time, CsF has weak resistance to humidity, making the quantum dot still easily degraded and damaged in a humid environment.

[0008] Correspondingly, the art needs a new technical solution to solve the above technical problems. Summary of the Invention

[0009] The present invention aims to solve the above technical problems, that is, to solve the problems of poor stability of fluorinated perovskite quantum dots and poor stability of the obtained fluorinated perovskite quantum dot light conversion film in the prior art.

[0010] In a first aspect, the present invention provides a calcium fluoride perovskite quantum dot, wherein the calcium fluoride perovskite quantum dot is CsPbX3:F, X is a halogen element selected from one of Cl, Br or I; fluorine element is doped in the calcium fluoride perovskite quantum dot, and F ions exist in the lattice of CsPbX3 quantum dots in the form of combining with Pb ions to form PbF2.

[0011] In a second aspect, the present invention provides a preparation method of the calcium fluoride perovskite quantum dot, wherein the preparation method includes:

[0012] Providing a solution A formed by a cesium source and an organic solvent A;

[0013] Providing a solution B formed by PbX2 and an organic solvent B, wherein X is a halogen element selected from one of Cl, Br or I;

[0014] Quickly injecting solution A and HF into solution B, then quickly cooling to room temperature, centrifuging to obtain a precipitate, and drying the obtained precipitate to obtain the calcium fluoride perovskite quantum dot.

[0015] In a preferred technical solution of the above preparation method, the mass-volume ratio of the cesium source to the organic solvent A is (0.02 - 0.04):(6 - 18) in g:mL;

[0016] And / or, the organic solvent A is a mixed solvent of oleic acid and 1-octadecene, and preferably the volume ratio of oleic acid to 1-octadecene in the mixed solvent is (1 - 2):(2 - 6).

[0017] In a preferred technical solution of the above preparation method, the cesium source is Cs2CO3 and / or CH3COOCs.

[0018] In a preferred technical solution of the above preparation method, the providing of the solution B formed by PbX2 and the organic solvent B is:

[0019] Dissolving PbX2 in the organic solvent B, heating to a temperature T1 and maintaining for a time t1 under inert gas degassing treatment to fully dissolve it and remove oxygen and moisture; then heating it to a temperature T2 and maintaining for a time t2 to obtain solution B.

[0020] In a preferred technical solution of the above preparation method, the mass-volume ratio of PbX2 to the organic solvent B is (0.4 - 1.2):(70 - 280) in g:mL;

[0021] And / or, the organic solvent B is a mixed solvent of methanol, oleic acid, oleylamine and 1-octadecene, and preferably the volume ratio of methanol, oleic acid, oleylamine and 1-octadecene in the mixed solvent is (0.5 - 1.5):1:1:(2 - 4);

[0022] And / or, the temperature T1 is 100 - 160 °C, preferably 120 °C;

[0023] And / or, the time t1 is 10 - 90 min, preferably 60 min;

[0024] And / or, the temperature T2 is 180 - 280 °C, preferably 250 °C;

[0025] And / or, the time t2 is 0 - 30 min, preferably 10 min.

[0026] In a preferred technical solution of the above preparation method, the dosage of HF is in a molar ratio of F / (F + X) of (0.2 - 0.6):1.

[0027] In a third aspect, the present invention provides a calcium fluoride perovskite quantum dot light conversion film, and the calcium fluoride perovskite quantum dot light conversion film includes the calcium fluoride perovskite quantum dots or the calcium fluoride perovskite quantum dots prepared by the above preparation method.

[0028] In a preferred technical solution of the above calcium fluoride perovskite quantum dot light conversion film, the calcium fluoride perovskite quantum dot light conversion film includes the following components:

[0029] In a fourth aspect, the present invention provides a preparation method of the calcium fluoride perovskite quantum dot light conversion film, wherein the preparation method includes the following steps:

[0030] Provide calcium fluoride perovskite quantum dot colloids;

[0031] Mix the calcium fluoride perovskite quantum dot colloids with a main crosslinking agent, a co-crosslinking agent, a coupling agent, a light stabilizer and an antioxidant, and then form a film by casting to obtain the film.

[0032] The calcium fluoride perovskite quantum dots, the calcium fluoride perovskite quantum dot light conversion film and the preparation method thereof of the present application have the following technical effects:

[0033] In the present invention, by using a fluorination strategy, F is anchored on the surface of the quantum dots to form PbF2, and the super strong ionic interaction of Pb - F is used to stabilize the entire quantum dots. Applying the fluorinated quantum dots to the photovoltaic film can prepare a highly stable calcium fluoride perovskite quantum dot light conversion film. Description of the Drawings

[0034] The following describes the preferred embodiments of the present invention with reference to the drawings, in which:

[0035] Figure 1 is the XPS peak diagram of the calcium fluoride perovskite quantum dots prepared in Example 1 of the present invention and the F1s of the perovskite quantum dots without doped F;

[0036] Figure 2 XPS peak patterns of Pb 4f of the calcium fluoride perovskite quantum dots prepared in Example 1 of the present invention and the perovskite quantum dots without F doping. Detailed implementation manners

[0037] The preferred implementation manners of the present invention will be described below with reference to the accompanying drawings. Those skilled in the art should understand that these implementation manners are only used to explain the technical principle of the present invention and are not intended to limit the protection scope of the present invention.

[0038] In this application, the term "and / or" describes the association relationship of associated objects and indicates that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, and B exists alone. Where A and B may be singular or plural. The character " / " generally represents an "or" relationship between the front and back associated objects.

[0039] In this application, "at least one" means one or more, and "a plurality" means two or more. "At least one of the following" or its similar expressions refer to any combination of these items, including any combination of single item(s) or plural item(s). For example, "at least one of a, b, or c", or, "at least one of a, b, and c" can both represent: a, b, c, a - b (i.e., a and b), a - c, b - c, or a - b - c, where a, b, and c can be single or multiple respectively.

[0040] It should be understood that in various embodiments of this application, the sequence numbers of the above - mentioned processes do not mean the order of execution. Some or all of the steps can be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of this application.

[0041] The terms used in the embodiments of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The singular forms of "a", "the", and "said" used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0042] The weights of the relevant components mentioned in the specification of the embodiments of this application not only can refer to the specific contents of each component, but also can represent the proportional relationship of the weights between each component. Therefore, as long as the contents of the relevant components in the specification of the embodiments of this application are scaled up or down in proportion, they are within the scope disclosed in the specification of the embodiments of this application. Specifically, the mass mentioned in the specification of the embodiments of this application can be mass units well - known in the chemical industry such as μg, mg, g, kg, etc.

[0043] The terms "first" and "second" are used only for descriptive purposes to distinguish objects such as substances from each other, and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. For example, without departing from the scope of the embodiments of the present application, the first XX may also be referred to as the second XX, and similarly, the second XX may also be referred to as the first XX. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features.

[0044] The experimental methods in the following embodiments are all conventional methods unless otherwise specified, and the materials, reagents, etc. used in the following embodiments can all be obtained from commercial channels unless otherwise specified.

[0045] Based on the problems of poor stability of perovskite quantum dots and poor stability of the obtained calcium fluoride perovskite quantum dot light conversion film in the prior art pointed out in the background art. In order to protect the quantum dots, the present invention proposes to use a new fluorination strategy to strengthen the bonding structure inside the quantum dots, form chemically stable Pb-F bonds in the perovskite quantum dots, and at the same time stabilize their internal lattices and passivate surface halide vacancies, thereby reducing their sensitivity to further chemical reactions with infiltrated water molecules and improving their stability.

[0046] Specifically, the present invention provides a calcium fluoride perovskite quantum dot in the first aspect, and the calcium fluoride perovskite quantum dot is CsPbX3:F, wherein X is a halogen element selected from one of Cl, Br or I; fluorine element is doped in the calcium fluoride perovskite quantum dot, and F ions exist in the lattice of the CsPbX3 quantum dot in the form of combining with Pb ions to form PbF2.

[0047] The calcium fluoride perovskite quantum dot provided by the present invention forms Pb-F bonds with higher bond energy and greater stability inside the quantum dots by using a new fluorination strategy, effectively inhibiting ion migration; the stable bonding of Pb-F bonds not only reduces the formation of halogen vacancies, thereby improving stability, but also can passivate the lead vacancy defects on the surface of the quantum dots, reduce non-radiative recombination, and further improve the quantum yield and the stability of the quantum dots.

[0048] The present invention provides a preparation method of the calcium fluoride perovskite quantum dot in the second aspect, wherein the preparation method includes:

[0049] Providing a solution A formed by a cesium source and an organic solvent A;

[0050] Providing a solution B formed by PbX2 and an organic solvent B, wherein X is a halogen element selected from one of Cl, Br or I;

[0051] Solution A and HF are rapidly injected into solution B, and then rapidly cooled to room temperature. The precipitate is obtained by centrifugal separation, and the obtained precipitate is dried to obtain the calcium fluoride perovskite quantum dots.

[0052] The fluorination strategy proposed in the present invention anchors F on the surface of the quantum dots to form PbF2, and uses the strong ionic interaction of Pb-F to stabilize the whole quantum dots.

[0053] In the present invention, the obtained precipitate can be dried by a commonly used drying method in the art. For example, in some specific embodiments, the drying method is drying by baking.

[0054] In some specific embodiments, the mass-volume ratio of the cesium source to organic solvent A is (0.02 - 0.04):(6 - 18) in g:mL. For example, it can be 0.02g:6mL, 0.04g:18mL, 0.03g:10mL, 0.03g:12mL or any value within the range of the mass-volume ratio.

[0055] In some specific embodiments, the organic solvent A is a mixed solvent of oleic acid and 1-octadecene, and preferably the volume ratio of oleic acid to 1-octadecene in the mixed solvent is (1 - 2):(2 - 6).

[0056] In some specific embodiments, the cesium source is Cs2CO3 and / or CH3COOCs.

[0057] In some specific embodiments, providing solution B formed by PbX2 and organic solvent B is as follows:

[0058] PbX2 is dissolved in organic solvent B, and under the degassing treatment of inert gas, it is heated to temperature T1 and maintained for time t1 to make it fully dissolve, and oxygen and moisture are removed; then it is heated to temperature T2 and maintained for time t2 to obtain solution B.

[0059] In the present invention, the inert gas is argon, helium, etc.

[0060] In some specific embodiments, the mass-volume ratio of PbX2 to organic solvent B is (0.4 - 1.2):(70 - 280) in g:mL. For example, it can be 0.4g:70mL, 1.2g:280mL, 0.8g:200mL, 1.0g:250mL or any value within the range of the mass-volume ratio.

[0061] In some specific embodiments, the organic solvent B is a mixed solvent of methanol, oleic acid, oleylamine and 1-octadecene, and preferably the volume ratio of methanol, oleic acid, oleylamine and 1-octadecene in the mixed solvent is (0.5 - 1.5):1:1:(2 - 4).

[0062] In some specific embodiments, the temperature T1 is 100 - 160 °C. For example, it can be 100 °C, 120 °C, 140 °C, 160 °C or any value within the temperature range.

[0063] In some preferred embodiments, the temperature T1 is 120 °C.

[0064] In some specific embodiments, the time t1 is 10 - 90 min. For example, it can be 10 min, 30 min, 50 min, 60 min, 90 min or any value within the time range.

[0065] In some preferred embodiments, the time t1 is 60 min.

[0066] In some specific embodiments, the temperature T2 is 180 - 280 °C. For example, it can be 180 °C, 200 °C, 220 °C, 240 °C, 260 °C, 280 °C or any value within the temperature range.

[0067] In some preferred embodiments, the temperature T2 is 250 °C.

[0068] In some specific embodiments, the time t2 is 0 - 30 min. For example, it can be 0 min, 5 min, 10 min, 15 min, 20 min, 30 min or any value within the time range.

[0069] In some preferred embodiments, the time t2 is 10 min.

[0070] In some specific embodiments, the dosage of HF is in a molar ratio of F / (F + X) of (0.2 - 0.6):1. For example, it can be 0.2:1, 0.25:1, 0.3:1, 0.35:1, 0.4:1, 0.45:1, 0.5:1, 0.55:1, 0.6:1 or any value within the ratio range.

[0071] The present invention provides a calcium fluoride perovskite quantum dot light conversion film in a third aspect. The calcium fluoride perovskite quantum dot light conversion film includes the calcium fluoride perovskite quantum dots or the calcium fluoride perovskite quantum dots prepared by the preparation method.

[0072] By using the fluorination strategy of the present invention, F is anchored to the surface of the quantum dots, and the strong ion interaction of Pb - F is utilized to stabilize the entire quantum dots. Further applying the fluorinated quantum dots to a photovoltaic film can prepare a highly stable calcium fluoride perovskite quantum dot light conversion film.

[0073] In some specific embodiments, the calcium fluoride perovskite quantum dot light conversion film includes the following components:

[0074] In some specific embodiments, the main crosslinking agent is at least one of triallyl cyanurate, triallyl isocyanurate, dipropylene glycol diacrylate, and pentaerythritol tetraacrylate.

[0075] In some specific embodiments, the co-crosslinking agent is one or more of trimethylolpropane trimethacrylate and triallyl isocyanurate.

[0076] In some specific embodiments, the coupling agent is one or more of vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, vinyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-(methacryloyloxy)propyltrimethoxysilane.

[0077] In some specific embodiments, the light stabilizer is one or more of 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-n-octoxybenzophenone, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-dipentylphenyl)benzotriazole, 2-(2'-hydroxy-5'-tert-octylphenyl)benzotriazole, and 2-phenylbenzimidazole-5-sulfonic acid.

[0078] In some specific embodiments, the antioxidant is one or more of tris(4-tert-butyl-3-hydroxy-2,6-dimethylphenyl) isocyanurate, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and tris(2,4-di-tert-butylphenyl) phosphite.

[0079] The present invention provides, in a fourth aspect, a method for preparing the calcium fluoride perovskite quantum dot light conversion film, wherein the preparation method comprises the following steps:

[0080] Providing calcium fluoride perovskite quantum dot colloidal particles;

[0081] Mixing the calcium fluoride perovskite quantum dot colloidal particles with the main crosslinking agent, co-crosslinking agent, coupling agent, light stabilizer, and antioxidant, and then forming a film by casting to obtain the film.

[0082] In some specific embodiments, the calcium fluoride perovskite quantum dot colloidal particles are provided by the following method:

[0083] First, disperse the calcium fluoride perovskite quantum dots in n-hexane, then add the obtained solution to blank colloidal particles, and control the quantum dot content in the colloidal particles to a preset content to obtain calcium fluoride perovskite quantum dot colloidal particles with a light conversion effect.

[0084] In some specific embodiments, the preset content is 5-20%, that is, the mass percentage of quantum dots in the blank colloidal particles is 5-20%.

[0085] In some specific embodiments, the blank colloidal particles are POE particles or EVA particles.

[0086] The present invention adopts a new fluorination strategy to obtain a fluorinated perovskite quantum dot CsPbX3:F. The fluorinated perovskite quantum dot forms a Pb-F bond with higher bond energy and greater stability inside the quantum dot, effectively inhibiting ion migration. The stable bonding of the Pb-F bond not only reduces the formation of halogen vacancies, thereby improving stability, but also passivates the lead vacancy defects on the surface of the quantum dot, reducing non-radiative recombination, and further improving the quantum yield and the stability of the quantum dot. The fluorinated perovskite quantum dot light conversion film prepared from the fluorinated perovskite quantum dot obtained by the method of the present invention has good stability under high temperature and high humidity environments and under ultraviolet lamp irradiation. With the extension of the storage time, the photoluminescence quantum yield does not change significantly.

[0087] The following several specific examples are used to illustrate in detail the fluorinated perovskite quantum dot, perovskite quantum dot film and preparation method of the present invention.

[0088] [Fluorinated perovskite quantum dot]

[0089] Example 1

[0090] This embodiment provides a fluorinated perovskite quantum dot, a perovskite quantum dot film and a preparation method thereof.

[0091] The fluorinated perovskite quantum dot obtained in this embodiment is CsPbBr3:F; the fluorinated perovskite quantum dot is doped with fluorine element.

[0092] The preparation method of the above-mentioned fluorinated perovskite quantum dot includes the following steps:

[0093] S1. Provide solution A formed by a cesium source and organic solvent A

[0094] Under the protection of an inert gas, dissolve the cesium source (Cs2CO3) in organic solvent A, continuously stir and heat until it is completely dissolved to obtain solution A.

[0095] Among them, the mass-volume ratio of Cs2CO3 to organic solvent A is 0.03 g:10 mL;

[0096] The organic solvent A is a mixed solvent of oleic acid and 1-octadecene, and the volume ratio of oleic acid to 1-octadecene in the mixed solvent is 1:5.

[0097] S2. Provide solution B formed by PbX2 and organic solvent B

[0098] Dissolve PbX2 in organic solvent B, and under the degassing treatment of an inert gas (argon), heat it to temperature T1 and hold for time t1 to fully dissolve it and remove oxygen and moisture; then heat it to temperature T2 and hold for time t2 to obtain solution B.

[0099] Among them, the PbX2 is PbBr2, and the mass-volume ratio of PbX2 to organic solvent B is 0.8 g: 200 mL;

[0100] The organic solvent B is a mixed solvent of methanol, oleic acid, oleylamine, and 1-octadecene, and the volume ratio of methanol, oleic acid, oleylamine, and 1-octadecene in the mixed solvent is 1:1:1:4;

[0101] Temperature T1 is 120 °C; time t1 is 60 min;

[0102] Temperature T2 is 250 °C; time t2 is 10 min.

[0103] S3. Prepare calcium fluoride perovskite quantum dots

[0104] Quickly inject the solution A obtained in step S1 and HF into the solution B obtained in step S2. Then, quickly cool it to room temperature, centrifuge to separate and remove the supernatant. Add the precipitate to n-hexane to disperse and dissolve it, then add ethanol and centrifuge to separate, remove the supernatant and retain the precipitate. Dry the obtained precipitate to obtain the calcium fluoride perovskite quantum dots.

[0105] Among them, the dosage of HF is in a molar ratio of F / (F + X) of 0.4:1, and X is Br.

[0106] The calcium fluoride perovskite quantum dots obtained in this example are CsPbBr3:F; the calcium fluoride perovskite quantum dots are doped with fluorine elements, and F ions exist in the lattice of CsPbBr3 quantum dots in the form of combining with Pb ions to form PbF2.

[0107] Perform XPS spectrum analysis on the calcium fluoride perovskite quantum dots CsPbBr3:F obtained in this example and the unfluorinated perovskite quantum dots CsPbBr3. Their XPS spectra are as Figure 1 and Figure 2 shown.

[0108] From Figure 1 it can be seen that a new XPS peak of the F1s state appears in the spectrum of CsPbBr3:F quantum dots, indicating that F ions are introduced into the lattice of the quantum dots.

[0109] From Figure 2It can be seen that, compared with the unfluorinated CsPbBr3 quantum dots, the Pb 4f peak in the CsPbBr3:F quantum dots shifts towards a higher binding energy, indicating the formation of Pb-F bonds with higher bond energy.

[0110] Example 2

[0111] The fluorinated perovskite quantum dots provided in this embodiment are CsPbCl3:F; fluorine element is doped in the fluorinated perovskite quantum dots.

[0112] The preparation method of the fluorinated perovskite quantum dots in this embodiment refers to Example 1. The differences from Example 1 are as follows:

[0113] In step S1, the mass-volume ratio of Cs2CO3 to organic solvent A is 0.02 g:6 mL;

[0114] In step S2, PbX2 is PbCl2.

[0115] Example 3

[0116] The fluorinated perovskite quantum dots provided in this embodiment are CsPbI3:F; fluorine element is doped in the fluorinated perovskite quantum dots.

[0117] The preparation method of the fluorinated perovskite quantum dots in this embodiment refers to Example 1. The differences from Example 1 are as follows:

[0118] In step S1, the mass-volume ratio of Cs2CO3 to organic solvent A is 0.04 g:18 mL;

[0119] In step S2, PbX2 is PbI2.

[0120] Example 4

[0121] The fluorinated perovskite quantum dots provided in this embodiment are the same as those in Example 1. The preparation method refers to Example 1. The differences from Example 1 are as follows:

[0122] In step S2, the mass-volume ratio of PbX2 to the mixed solvent is 0.4 g:70 mL; temperature T1 is 100 °C; time t1 is 10 min; temperature T2 is 180 °C; time t2 is 0 min.

[0123] Example 5

[0124] The fluorinated perovskite quantum dots provided in this embodiment are the same as those in Example 1. The preparation method refers to Example 1. The differences from Example 1 are as follows:

[0125] In step S2, the mass-volume ratio of PbX2 to the mixed solvent is 1.2 g: 280 mL; the temperature T1 is 160 °C; the time t1 is 90 min; the temperature T2 is 280 °C; the time t2 is 30 min;

[0126] In step S3, the dosage of HF is 0.2:1 in terms of the molar ratio of F / (F + X).

[0127] Example 6

[0128] The calcium fluoride perovskite quantum dots provided in this example are the same as those in Example 1, and the preparation method refers to Example 1. The difference from Example 1 is:

[0129] In step S2, the mass-volume ratio of PbX2 to the mixed solvent is 0.6 g: 150 mL; the temperature T1 is 135 °C; the time t1 is 30 min; the temperature T2 is 230 °C; the time t2 is 16 min;

[0130] In step S3, the dosage of HF is 0.6:1 in terms of the molar ratio of F / (F + X).

[0131] Example 7

[0132] The calcium fluoride perovskite quantum dots provided in this example are the same as those in Example 1, and the preparation method refers to Example 1. The difference from Example 1 is:

[0133] In step S1, the cesium source is CH3COOCs.

[0134] Example 8

[0135] The calcium fluoride perovskite quantum dots provided in this example are the same as those in Example 1, and the preparation method refers to Example 1. The difference from Example 1 is:

[0136] In step S1, the volume ratio of oleic acid to 1-octadecene in the mixed solvent is 1:2.

[0137] Example 9

[0138] The calcium fluoride perovskite quantum dots provided in this example are the same as those in Example 1, and the preparation method refers to Example 1. The difference from Example 1 is:

[0139] In step S1, the volume ratio of oleic acid to 1-octadecene in the mixed solvent is 2:6.

[0140] Example 10

[0141] The calcium fluoride perovskite quantum dots provided in this example are the same as those in Example 1, and the preparation method refers to Example 1. The difference from Example 1 is:

[0142] In step S2, the volume ratio of methanol, oleic acid, oleylamine and 1-octadecene in the mixed solvent is 0.5:1:1:2.

[0143] Example 11

[0144] The calcium fluoride perovskite quantum dots provided by this example are the same as those in Example 1. The preparation method refers to Example 1. The difference from Example 1 is:

[0145] In step S2, the volume ratio of methanol, oleic acid, oleylamine and 1-octadecene in the mixed solvent is 1.5:1:1:4.

[0146] Comparative Example 1

[0147] Preparation of all-inorganic fluorinated CsPbBr3 quantum dots

[0148] Weigh 0.1 mmol of cesium carbonate and 0.2 mmol of lead acetate into a two-necked round-bottom flask at room temperature. Add 1 mL of oleic acid, 1 mL of oleylamine, 1 mL of trioctylphosphine and 10 mL of octadecene as solvents. Heat to 120 °C under an inert atmosphere and stir to dissolve for 1 hour. Heat the solution to 200 °C, quickly inject a mixture of 115 μL of hydrobromic acid and 30 μL of hydrofluoric acid. After reacting for 10 seconds, quickly cool the reaction solution to room temperature in an ice-water bath, and centrifugally separate and purify to obtain all-inorganic fluorinated CsPbBr3 quantum dots.

[0149] Comparative Example 2

[0150] Preparation of all-inorganic fluorinated CsPbCl3 quantum dots

[0151] Weigh 0.1 mmol of cesium carbonate and 0.2 mmol of lead acetate into a two-necked round-bottom flask at room temperature. Add 1 mL of oleic acid, 1 mL of oleylamine, 1 mL of trioctylphosphine and 10 mL of octadecene as solvents. Heat to 120 °C under an inert atmosphere and stir to dissolve for 1 hour. Heat the solution to 200 °C, quickly inject a mixture of 150 μL of hydrochloric acid and 30 μL of hydrofluoric acid. After reacting for 10 seconds, quickly cool the reaction solution to room temperature in an ice-water bath, and centrifugally separate and purify to obtain all-inorganic fluorinated CsPbCl3 quantum dots.

[0152] Comparative Example 3

[0153] Preparation of all-inorganic fluorinated CsPbI3 quantum dots

[0154] Weigh 0.1 mmol of cesium carbonate and 0.2 mmol of lead acetate into a two-necked round-bottom flask at room temperature. Add 1 mL of oleic acid, 1 mL of oleylamine, 1 mL of trioctylphosphine, and 10 mL of octadecene as solvents. Heat to 120 °C under an inert atmosphere and stir to dissolve for 1 hour. Heat the solution to 200 °C, quickly inject a mixture of 175 μL of hydroiodic acid and 30 μL of hydrofluoric acid. After reacting for 10 seconds, quickly cool the reaction solution to room temperature in an ice-water bath, and obtain all-inorganic fluorinated CsPbI3 quantum dots by centrifugal separation and purification.

[0155] [Calcium fluoride perovskite quantum dot light conversion adhesive film]

[0156] The present invention further provides a calcium fluoride perovskite quantum dot light conversion adhesive film including the above-mentioned calcium fluoride perovskite quantum dots and a preparation method. The components of the calcium fluoride perovskite quantum dot light conversion adhesive film in each example are shown in Table 1, and its preparation method includes the following steps:

[0157] (1) First, disperse the calcium fluoride perovskite quantum dots in n-hexane, and then add the obtained solution to blank colloidal particles, controlling the quantum dot content in the colloidal particles (shown in Table 1) to obtain calcium fluoride perovskite quantum dot colloidal particles with light conversion effect;

[0158] (2) Weigh the calcium fluoride perovskite quantum dot colloidal particles, main cross-linking agent, co-cross-linking agent, coupling agent, light stabilizer, and antioxidant according to the amounts shown in Table 1. After mixing them evenly, add them to a twin-screw extruder and extrude at 80 °C. The temperatures of the inlet section, middle section, and outlet section of the extruder are set to 60 °C, 70 °C, and 80 °C. After extrusion, add them to a casting machine and cast into a film at 80 °C, emboss, and cool to obtain a fluorinated quantum dot light conversion adhesive film.

[0159] Table 1. Components of the calcium fluoride perovskite quantum dot light conversion adhesive film in each example

[0160] Comparative Example 1'

[0161] This comparative example provides a calcium fluoride perovskite quantum dot light conversion adhesive film. The preparation method is the same as described above, and the components refer to Example 1. The difference from Example 1 is that the quantum dots used are all-inorganic fluorinated CsPbBr3 quantum dots prepared in Comparative Example 1.

[0162] Comparative Example 2'

[0163] This comparative example provides a calcium fluoride perovskite quantum dot light conversion adhesive film. The preparation method is the same as described above, and the components refer to Example 2. The difference from Example 2 is that the quantum dots used are all-inorganic fluorinated CsPbCl3 quantum dots prepared in Comparative Example 2.

[0164] Comparative Example 3'

[0165] This comparative example provides a calcium fluoride perovskite quantum dot light conversion film. The preparation method is the same as described above, and the components refer to Example 3. The difference from Example 3 is that the quantum dots used are all-inorganic CsPbI3 fluoride quantum dots prepared in Comparative Example 3.

[0166] Test Example 1

[0167] This test example examines the stability of the calcium fluoride perovskite quantum dot light conversion film of the present invention and the calcium fluoride perovskite quantum dot light conversion film of the comparative example.

[0168] Test method: On the photovoltaic glass, in the order of photovoltaic glass, quantum dot film, and photovoltaic glass, stack them in sequence, then put them into a laminator and laminate at 145 °C to obtain a photovoltaic glass module. The calcium fluoride perovskite quantum dot light conversion films prepared in Examples 1'-3' and Comparative Examples 1'-3' are used as the middle quantum dot film layer respectively, and after laminating according to the above method, photovoltaic glass modules are obtained, and the photoluminescence quantum yields of each module placed in a high-temperature and high-humidity (temperature 85 °C and humidity 85%) environment for different times are measured.

[0169] The test results are shown in Table 2:

[0170] Table 2. Stability test results of calcium fluoride perovskite quantum dot light conversion film

[0171] It can be seen from the above results that compared with Comparative Examples 1', 2', and 3', the calcium fluoride perovskite quantum dot light conversion film prepared with the calcium fluoride perovskite quantum dots prepared by the method of the present invention has good stability under high temperature and high humidity, and the photoluminescence quantum yield has no obvious change with the extension of the placement time.

[0172] Test Example 2

[0173] This test example examines the stability of the calcium fluoride perovskite quantum dot light conversion film of the present invention and the calcium fluoride perovskite quantum dot light conversion film of the comparative example.

[0174] Test method: On the photovoltaic glass, in the order of photovoltaic glass, quantum dot film, and photovoltaic glass, stack them in sequence, then put them into a laminator and laminate at 145 °C to obtain a photovoltaic glass module. The calcium fluoride perovskite quantum dot light conversion films prepared in each of Examples 1'-3' and Comparative Examples 1'-3' are used as the middle quantum dot film layer respectively, and after laminating according to the above method, photovoltaic glass modules are obtained, and the photoluminescence quantum yields of each module irradiated under a 100 W / m 2 UVA + UVB ultraviolet lamp for different times are measured.

[0175] The test results are shown in Table 3:

[0176] Table 3. Stability test results of calcium fluoride perovskite quantum dot light conversion film

[0177] It can be seen from the above results that, compared with Comparative Example 1', Comparative Example 2' and Comparative Example 3', the calcium fluoride perovskite quantum dot light conversion film prepared from the calcium fluoride perovskite quantum dots prepared by the method of the present invention has good stability under ultraviolet lamp irradiation, and the photoluminescence quantum yield does not change significantly with the extension of the storage time.

[0178] So far, the technical solution of the present invention has been described in combination with the preferred embodiments shown in the drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. A calcium fluoride perovskite quantum dot, characterized in that, The calcium fluoride perovskite quantum dots are CsPbX3:F, where X is a halogen element selected from one of Cl, Br or I; the calcium fluoride perovskite quantum dots are doped with fluorine elements, and F ions exist in the lattice of CsPbX3 quantum dots in the form of combining with Pb ions to form PbF2.

2. The preparation method of the calcium fluoride perovskite quantum dots according to claim 1, characterized in that, The preparation method described above includes: Providing solution A formed by a cesium source and organic solvent A; Providing solution B formed by PbX2 and organic solvent B, where X is a halogen element selected from one of Cl, Br or I; Quickly injecting solution A and HF into solution B, then quickly cooling to room temperature, centrifuging to obtain a precipitate, and drying the obtained precipitate to obtain the calcium fluoride perovskite quantum dots.

3. The preparation method according to claim 2, wherein The mass-volume ratio of the cesium source to organic solvent A is (0.02 - 0.04):(6 - 18) in g:mL; And / or, the organic solvent A is a mixed solvent of oleic acid and 1-octadecene, and preferably the volume ratio of oleic acid to 1-octadecene in the mixed solvent is (1 - 2):(2 - 6).

4. The preparation method according to claim 3, wherein The cesium source is Cs2CO3 and / or CH3COOCs.

5. The preparation method according to claim 2, characterized in that, The step of providing solution B formed by PbX2 and organic solvent B is: Dissolving PbX2 in organic solvent B, and heating to temperature T1 and maintaining for time t1 under inert gas degassing treatment; then heating it to temperature T2 and maintaining for time t2 to obtain solution B.

6. The preparation method according to claim 5, wherein The mass-volume ratio of PbX2 to organic solvent B is (0.4 - 1.2):(70 - 280) in g:mL; And / or, the organic solvent B is a mixed solvent of methanol, oleic acid, oleylamine and 1-octadecene, and preferably the volume ratio of methanol, oleic acid, oleylamine and 1-octadecene in the mixed solvent is (0.5 - 1.5):1:1:(2 - 4); And / or, the temperature T1 is 100 - 160 °C, preferably 120 °C; And / or, the time t1 is 10 - 90 min, preferably 60 min; And / or, the temperature T2 is 180 - 280 °C, preferably 250 °C; And / or, the time t2 is 0 - 30 min, preferably 10 min.

7. The preparation method according to claim 2, characterized in that, The dosage of HF is in the molar ratio of F / (F + X) of (0.2 - 0.6):

1.

8. A calcium fluoride perovskite quantum dot light conversion adhesive film, characterized in that, The calcium fluoride perovskite quantum dot light conversion film includes the calcium fluoride perovskite quantum dots described in claim 1 or the calcium fluoride perovskite quantum dots prepared by the preparation method described in any one of claims 2 - 7.

9. The calcium fluoride perovskite quantum dot light conversion adhesive film according to claim 8, wherein The calcium fluoride perovskite quantum dot light conversion film includes the following components:

10. A method for preparing a calcium fluoride perovskite quantum dot light conversion adhesive film according to claim 8 or 9, characterized in that, The preparation method includes the following steps: Providing calcium fluoride perovskite quantum dot colloids; Mixing the calcium fluoride perovskite quantum dot colloids with a main crosslinking agent, a co-crosslinking agent, a coupling agent, a light stabilizer and an antioxidant, and then forming a film by casting to obtain the product.

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