Preparation method of light conversion packaging adhesive film for solar cell

Abstract

The invention provides a preparation method of a light conversion packaging adhesive film for a solar cell, and the method comprises the steps: preparing perovskite quantum dots, an alkaline earth metal chloride solution and a perovskite quantum dot packaging adhesive film, and carrying out the reaction of Cs2CO3, oleic acid and 1-octadecene under the protection of inert gas to prepare a precursor A; adding PbCl2 and transition metal chloride into a mixed solvent to prepare a solution B; after heating, adding the precursor A into the solution B for reaction to obtain a perovskite quantum dot solution; mixing the perovskite quantum dot solution, the blank colloidal particles and an alkaline earth metal chloride solution, and performing melt extrusion and granulation to obtain perovskite quantum dot colloidal particles; and mixing the perovskite quantum dot colloidal particles with a coupling agent, a cross-linking agent, a light stabilizer, an antioxidant and other components, and carrying out film casting to obtain the packaging adhesive film. According to the invention, the photoluminescence quantum efficiency of perovskite and the optical performance of the packaging adhesive film are significantly improved, and the problem of low luminous efficiency of the existing perovskite quantum dot adhesive film is solved.

Description

Technical Field

[0001] The present invention relates to the field of new energy photovoltaic technology, and in particular to a method for preparing a light conversion packaging adhesive film for solar cells. Background Art

[0002] In recent years, with the growing global demand for renewable energy, the photovoltaic solar cell industry has developed rapidly. Silicon-based solar cells are widely used in photovoltaic cells due to their theoretical photoelectric conversion efficiency of up to 30% and low production cost, becoming the mainstream choice in the market. Although silicon-based cells have a wide spectral response range, the light utilization rate in the ultraviolet and near-ultraviolet regions is low, resulting in some solar energy not being effectively converted into electrical energy, causing energy loss. In addition, silicon-based photovoltaic devices are prone to aging when exposed to ultraviolet radiation for a long time, causing irreversible decline in cell efficiency and affecting the service life of the components. Therefore, how to improve the utilization rate of ultraviolet and near-ultraviolet light and protect photovoltaic components has become an important research direction in the photovoltaic field.

[0003] In recent years, perovskite materials have gradually become a research hotspot in the photovoltaic field due to their unique optical and electrical properties. Perovskite materials have excellent characteristics such as "low cost" and "can be combined with crystalline silicon stacking". Its notable feature is that it can absorb ultraviolet and near-ultraviolet light that silicon-based cells cannot use, and convert it into visible light that silicon-based cells can use, thereby improving the overall efficiency of photovoltaic modules. At present, there have been studies trying to combine perovskite materials with silicon-based solar cell stacks to prepare perovskite-crystalline silicon stacked cells, but this technology has the following defects: stacked cells require precise interface control processes, the current technology is not mature, and the preparation cost is high; the photoluminescence quantum efficiency of traditional ABX3 perovskite materials is still low, and has not yet reached the requirements for application in photovoltaic encapsulation films, which restricts the further improvement of its performance. Perovskite film technology is still in the early stages of development. The perovskite film prepared by co-extruding perovskite quantum dots and resin polymers can not only play the role of bonding ordinary films, but also use high-energy ultraviolet and near-ultraviolet light for light conversion, but its low light conversion efficiency still needs to be further solved.

[0004] Therefore, it is necessary to provide a method for improving the quantum efficiency of perovskite and applying it to the preparation of photovoltaic encapsulation films. By optimizing the preparation and functional design of perovskite quantum dots, the photoluminescence quantum efficiency can be significantly improved, thereby effectively utilizing ultraviolet and near-ultraviolet light. Summary of the invention

[0005] According to the technical problems raised above, a method for preparing a light conversion encapsulation film for solar cells is provided, which aims to improve the light conversion efficiency of photovoltaic modules for ultraviolet and near-ultraviolet light at a lower cost by improving the performance of perovskite quantum dots and the optical properties of the encapsulation film, while enhancing the stability of the modules and extending their service life.

[0006] The technical means adopted by the present invention are as follows:

[0007] A method for preparing a light conversion encapsulation film for solar cells comprises the following steps:

[0008] S1. Preparation of perovskite quantum dots PQDs: dissolving Cs2CO3 in 1-octadecene and oleic acid to prepare precursor A; weighing a certain amount of PbCl2 and transition metal chloride and adding them to a mixed solvent of oleic acid, oleylamine and 1-octadecene to prepare solution B; heating to a specified temperature, adding precursor A to solution B, centrifuging the reaction solution through precipitation to obtain perovskite quantum dots PQDs, and dissolving with hexane to obtain a perovskite quantum dot solution;

[0009] S2. preparing an alkaline earth metal chloride solution: dissolving a certain amount of alkaline earth metal chloride in a solvent to obtain an alkaline earth metal chloride solution;

[0010] S3. Preparation of perovskite quantum dot encapsulation adhesive film: mixing the perovskite quantum dot solution, blank colloid particles and alkaline earth metal chloride solution, and obtaining perovskite quantum dot colloid particles by melt extrusion and granulation; mixing the perovskite quantum dot colloid particles with a coupling agent, a primary cross-linking agent, an auxiliary cross-linking agent, a light stabilizer and an antioxidant, and then melt-extruded, and obtaining the perovskite quantum dot adhesive film by cast film formation.

[0011] Furthermore, in step S1, the ratio of PbCl2 to transition metal chloride is (3-6) mmol: (3-6) mmol, and the ratio of the mixed solvent of oleic acid, oleylamine and 1-octadecene is (40-60) ml: (40-60) ml: (30-80) ml.

[0012] Furthermore, in the step S1, the transition metal chloride is ZnCl2, MnCl2 or CoCl2.

[0013] Furthermore, the dosage ratio of Cs2CO3, 1-octadecene and oleic acid is (0.03-0.08) mol: (60-80) ml: (10-30) ml, and the heating temperature is 120-180°C.

[0014] Furthermore, in the step S1, the heating temperature T1 of the solution B is 100-180°C, and the holding time t1 is 20-60 minutes; the reaction temperature T2 is 140-280°C, and the reaction time t2 is 20-60 minutes.

[0015] Furthermore, in the step S1, the volume ratio of the precursor A to the solution B is (3-10): (90-97), the reaction time is 10-60 seconds; and the concentration of the perovskite quantum dot solution is 20-30%.

[0016] Furthermore, in step S2, the ratio of alkaline earth metal chloride to solvent is (3-6) mmol: (10-30) ml, and the concentration is 0.1-0.6 mol / L; the alkaline earth metal chloride is MgCl2, CaCl2 or BaCl2; and the solvent is one of ethanol, methanol, isopropanol or ethyl acetate.

[0017] Furthermore, in step S3, the mass ratio of the perovskite quantum dot solution, the blank colloid particles and the alkaline earth metal chloride solution is (5-8): (20-40): (3-5); the mixing conditions are a temperature of 20-120°C and a time of 0.2-2h; the melt extrusion conditions are a temperature of 50-200°C, a time of 0.2-2 hours, and a rotation speed of 20-80rpm; and the granulation temperature is 80-150°C.

[0018] Furthermore, in step S3, during the film casting process, the temperature is 70-150° C. and the film thickness is 0.2-0.5 mm.

[0019] Further, in step S3, 80-105 parts of perovskite quantum dot colloid particles, 0.1-2 parts of coupling agent, 0.4-2 parts of main cross-linking agent, 0.4-2 parts of auxiliary cross-linking agent, 0.05-0.2 parts of light stabilizer and 0.05-0.2 parts of antioxidant are weighed, mixed and melt-extruded.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] 1. The present invention introduces alkaline earth metal chlorides (such as MgCl2, CaCl2 or BaCl2) to passivate and repair defects on the surface of perovskite quantum dots, thereby significantly improving the photoluminescence quantum yield (PLQY) of quantum dots. Alkaline earth metal chlorides can repair halogen vacancies on the surface of quantum dots, reduce the number of surface defect states, and thus reduce the probability of non-radiative recombination; alkaline earth metal ions attach to the surface of quantum dots to play a passivating role. This passivation and repair effect effectively improves the luminescence efficiency of perovskite quantum dots, increasing PLQY by 32-41%, meeting the high performance requirements of photovoltaic encapsulation films.

[0022] 2. In the process of preparing the perovskite quantum dot film, the present invention optimizes the mixing ratio of the quantum dot solution, the blank colloid particles and the alkaline earth metal chloride solution to ensure the uniform distribution of the quantum dots in the colloid particles, and further utilizes the repairing effect of the alkaline earth metal ions on the quantum dots, so that the film has excellent light conversion performance. Perovskite quantum dots can efficiently absorb ultraviolet light and near-ultraviolet light and convert them into visible light, thereby improving the utilization rate of sunlight by photovoltaic modules and optimizing the photoelectric conversion efficiency of the modules.

[0023] 3. The perovskite quantum dot adhesive film prepared by the present invention has been tested for environmental stability and has shown good heat resistance, moisture resistance and light decay resistance. The introduction of alkaline earth metal chloride effectively enhances the chemical stability of perovskite quantum dots in high humidity and strong light environments; the addition of coupling agents improves the interfacial bonding between quantum dots and resin polymers, preventing quantum dots from desorbing or agglomerating due to environmental influences; the addition of light stabilizers further inhibits light degradation.

[0024] 4. The present invention adopts the process of melt extrusion and cast film formation to realize the integrated preparation process of perovskite quantum dot encapsulation film. Compared with the existing complex interface stacking technology, the preparation process of the present invention is simple to operate and has high production efficiency, which significantly reduces the preparation cost of the film. In addition, by optimizing the process parameters such as temperature and rotation speed, the quality consistency and production stability of the film are ensured.

[0025] In summary, the perovskite quantum dot film of the present invention can not only improve the light utilization efficiency of ultraviolet light and near-ultraviolet light, but also has the bonding protection function of ordinary photovoltaic encapsulation film. The thickness of the film is controlled within the range of 0.2-0.5mm, taking into account excellent light transmittance and mechanical strength, and providing long-term physical protection and performance stability support for photovoltaic modules. It has the advantages of simple and efficient preparation process, low cost, and product performance that meets the dual needs of photovoltaic modules for efficient light conversion and long-term encapsulation, and can be widely promoted in the field of new energy photovoltaic technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0027] Figure 1 This is a comparison spectrum of the photoluminescence quantum yield of the perovskite quantum dot film embodiment 3 of the present invention and the comparative example 3.

[0028] Figure 2 This is a sample picture of the perovskite quantum dot film tested by the present invention. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] The present invention provides a method for preparing a light conversion encapsulation film for solar cells, comprising preparing perovskite quantum dots PQDs, preparing an alkaline earth metal chloride solution and preparing an encapsulation film, and the specific steps are as follows:

[0031] S1. Preparation of perovskite quantum dots PQDs:

[0032] S11. Preparation of precursor A: dissolve Cs2CO3 in 1-octadecene and oleic acid, heat under inert gas protection and stir continuously until all dissolved to obtain precursor A; the dosage ratio of Cs2CO3, 1-octadecene and oleic acid is (0.03-0.08) mol: (60-80) ml: (10-30) ml, and the heating temperature is 120-180°C.

[0033] S12. Prepare solution B: weigh a certain amount of PbCl2 and transition metal chloride, add a mixed solvent of oleic acid, oleylamine and 1-octadecene, heat to temperature T1 under inert gas protection and stir continuously, maintain for time t1, and obtain solution B; the dosage ratio of PbCl2 to transition metal chloride is (3-6) mmol: (3-6) mmol, and the ratio of the mixed solvent of oleic acid, oleylamine and 1-octadecene is (40-60) ml: (40-60) ml: (30-80) ml; the transition metal chloride is ZnCl2, MnCl2 or CoCl2.

[0034] Specifically, the heating temperature T1 of solution B is 100-180°C, preferably 120-160°C; the holding time t1 is 20-60min, preferably 30-50min; the reaction temperature T2 is 140-280°C, preferably 150-250°C; the reaction time t2 is 20-60min, preferably 30-50min.

[0035] S13, preparation of perovskite quantum dots PQDs: heating to T2, taking a certain amount of precursor A and adding it to solution B, cooling to room temperature after reaction time t2; the reaction solution is subjected to precipitation and centrifugation to obtain perovskite quantum dots PQDs, and the perovskite quantum dot solution is dissolved in hexane. The volume ratio of precursor A to solution B is (3-10): (90-97), preferably (5-8): (92-95); the reaction time is 10-60 seconds; the concentration of the perovskite quantum dot solution is 20-30%.

[0036] S2. Preparation of alkaline earth metal chloride solution: dissolving a certain amount of alkaline earth metal chloride in a solvent to obtain an alkaline earth metal chloride solution; the ratio of alkaline earth metal chloride to solvent is (3-6) mmol: (10-30) ml, and the concentration is 0.1-0.6 mol / L; the alkaline earth metal chloride is MgCl2, CaCl2 or BaCl2; the solvent is one of ethanol, methanol, isopropanol or ethyl acetate.

[0037] S3. Preparation of perovskite quantum dot encapsulation film:

[0038] S31. Preparation of perovskite quantum dot colloid particles: mix perovskite quantum dot solution, blank colloid particles and alkaline earth metal chloride solution in a mass ratio of (5-8): (20-40): (3-5), wherein the mixing conditions are a temperature of 20-120°C and a time of 0.2-2h; obtain perovskite quantum dot colloid particles through melt extrusion and granulation; wherein the melt extrusion conditions are a temperature of 50-200°C, a time of 0.2-2 hours, and a rotation speed of 20-80rpm; the granulation temperature is 80-150°C; the blank colloid particles refer to one or both of POE and EVA colloid particles.

[0039] S32, preparing adhesive film: weigh 80-105 parts of perovskite quantum dot particles, 0.1-2 parts of coupling agent, 0.4-2 parts of primary crosslinking agent, 0.4-2 parts of auxiliary crosslinking agent, 0.05-0.2 parts of light stabilizer and 0.05-0.2 parts of antioxidant by weight; mix well and melt extrude, and form a film by casting to obtain the perovskite quantum dot adhesive film. During the casting process, the temperature is 70-150°C and the thickness of the adhesive film is 0.2-0.5mm.

[0040] Specifically, the coupling agent includes one or more of a vinyl silane coupling agent, an epoxy silane coupling agent, an alkyl silane coupling agent, an amino silane coupling agent, an isocyanate silane coupling agent, a sulfur-containing silane coupling agent or a piperazine silane coupling agent.

[0041] The main cross-linking agent includes one or more of 2-ethylhexyl peroxide tert-butyl carbonate, 2,5-dimethyl-2,5-di-tert-butyl peroxide hexane, diisopropylbenzene peroxide and 1,1-di-tert-butyl peroxide-3,3,5-trimethylcyclohexane.

[0042] The auxiliary cross-linking agent includes one or more of triallyl isocyanurate, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate and ethoxylated trimethylolpropane triacrylate.

[0043] The light stabilizer includes one or more of bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, poly(4-hydroxy-2,2,6,6-tetramethyl-1-piperidinylethanol) succinate, and bis(1,2,2,6,6-pentamethylpiperidinol) sebacate.

[0044] The antioxidant includes one or more of aromatic amine antioxidants, hindered phenol antioxidants and phosphite antioxidants.

[0045] Example 1

[0046] 1. Preparation of Perovskite Quantum Dots (PQDs)

[0047] 1.1) Preparation of precursor A: Dissolve 0.03 mol Cs2CO3 in a mixed solvent of 60 ml ODE and 15 ml oleic acid, stir continuously and heat to 120°C under inert gas protection to completely dissolve the precursor A;

[0048] 1.2) Preparation of solution B: weigh 6 mmol PbCl2 and 3 mmol ZnCl2, add 40 ml oleic acid, 40 ml oleylamine and 50 ml 1-octadecene, stir and dissolve under inert gas protection and heat to 150°C for 40 min to obtain solution B;

[0049] 1.3) Preparation of quantum dots PQDs: 8 ml of precursor solution A was added to 130 ml of solution B, reacted for 30 seconds and then cooled to room temperature; methyl acetate was added to precipitate, centrifuged and washed three times, and a perovskite quantum dot solution with a mass fraction of 20% was prepared with hexane.

[0050] 2. Preparation of alkaline earth metal chloride solution

[0051] Dissolve 3 mmol of alkaline earth metal chloride MgCl2 in a certain amount of ethyl acetate and dissolve by ultrasonication to prepare 25 g of solution.

[0052] 3. Preparation of film

[0053] 3.1) Perovskite quantum dot colloid particles: 40 g of perovskite quantum dot solution, 300 g of EVA colloid particles and 25 g of MgCl2 solution were mixed at 70°C for 1.2 h, then melt-extruded at 100°C and 30 rpm for 0.5 h, and finally granulated at 80°C to obtain perovskite quantum dot colloid particles;

[0054] 3.2) Preparation of adhesive film: Weigh 80 g of perovskite quantum dot particles, 1 g of dodecyltrimethoxysilane, 1 g of diisopropylbenzene peroxide, 1 g of trimethylolpropane triacrylate, 0.1 g of bis(1,2,2,6,6-pentamethylpiperidinol)sebacate and 0.1 g of tri[2.4-di-tert-butylphenyl]phosphite; mix them evenly, melt extrude them, and form them into a film by a casting method. The temperature in the casting method is 100°C to obtain a perovskite quantum dot adhesive film.

[0055] Example 2

[0056] 1. Preparation of Perovskite Quantum Dots (PQDs)

[0057] 1.1) Preparation of precursor A: Dissolve 0.08 mol Cs2CO3 in a mixed solvent of 80 ml ODE and 25 ml oleic acid, stir continuously and heat to 150°C under inert gas protection to completely dissolve the precursor A;

[0058] 1.2) Preparation of solution B: Weigh 4 mmol PbCl2 and 6 mmol CoCl2, add 40 ml oleic acid, 50 ml oleylamine and 80 ml 1-octadecene, stir and dissolve under inert gas protection and heat to 170°C for 30 min to obtain solution B;

[0059] 1.3) Preparation of quantum dots PQDs: 10 ml of precursor solution A was added to 170 ml of solution B, reacted for 40 seconds and then cooled to room temperature; methyl acetate was added to precipitate, centrifuged and washed three times, and a perovskite quantum dot solution with a mass fraction of 25% was prepared with hexane.

[0060] 2. Preparation of alkaline earth metal chloride solution

[0061] Dissolve 4 mmol of alkaline earth metal chloride CaCl2 in a certain amount of methanol and dissolve by ultrasonication to prepare 28 g of solution.

[0062] 3. Preparation of film

[0063] 3.1) Perovskite quantum dot colloid particles: 35 g of perovskite quantum dot solution, 280 g of POE colloid particles and 28 g of CaCl2 solution were mixed at 100°C for 1 h, then melt-extruded at 120°C and 60 rpm for 1.0 h, and finally granulated at 130°C to obtain perovskite quantum dot colloid particles;

[0064] 3.2) Preparation of adhesive film: Weigh 90 g of perovskite quantum dot particles, 1.2 g of 3-isocyanatopropyltriethoxysilane, 0.8 g of tert-butyl 2-ethylhexyl carbonate, 0.6 g of ethoxylated trimethylolpropane triacrylate, 0.15 g of poly(4-hydroxy-2,2,6,6-tetramethyl-1-piperidinylethanol) succinate and 0.15 g of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate); mix them evenly, melt extrude them, and form them into films by a casting method. The temperature in the casting method film forming process is 85°C to obtain a perovskite quantum dot adhesive film.

[0065] Example 3

[0066] 1. Preparation of Perovskite Quantum Dots (PQDs)

[0067] 1.1) Preparation of precursor A: Dissolve 0.06 mol Cs2CO3 in a mixed solvent of 70 ml ODE and 30 ml oleic acid, stir continuously and heat to 160°C under inert gas protection to completely dissolve the precursor A;

[0068] 1.2) Preparation of solution B: weigh 3 mmol PbCl2 and 6 mmol MnCl2, add 50 ml oleic acid, 50 ml oleylamine and 60 ml 1-octadecene, stir and dissolve under inert gas protection and heat to 180°C for 50 min to obtain solution B;

[0069] 1.3) Preparation of quantum dots PQDs: 11 ml of precursor solution A was added to 160 ml of solution B, reacted for 20 seconds and then cooled to room temperature; methyl acetate was added to precipitate, centrifuged and washed three times, and a perovskite quantum dot solution with a mass fraction of 30% was prepared with hexane.

[0070] 2. Preparation of alkaline earth metal chloride solution

[0071] 4.5 mmol of alkaline earth metal chloride BaCl2 was dissolved in a certain amount of ethanol and dissolved by ultrasonic to prepare 22 g of solution.

[0072] 3. Preparation of film

[0073] 3.1) Perovskite quantum dot colloid particles: 35 g of perovskite quantum dot solution, 200 g of EVA colloid particles and 22 g of BaCl2 solution were mixed at 120°C for 0.8 h, then melt-extruded at a temperature of 130°C and a rotation speed of 80 rpm for 1.5 h, and finally granulated at 80°C to obtain perovskite quantum dot colloid particles;

[0074] 3.2) Preparation of adhesive film: 100 g of perovskite quantum dot particles, 1.2 g of γ-glycidyloxypropyltrimethoxysilane, 1 g of 2,5-dimethyl-2,5-di-tert-butylperoxide hexane, 0.8 g of trimethylolpropane trimethacrylate, 0.2 g of poly(4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol) succinate and 0.2 g of 2,6-di-tert-butyl-4-methylphenol were weighed and mixed evenly, then melt-extruded and formed into a film by a casting method. The temperature in the casting method film forming process was 95°C to obtain a perovskite quantum dot adhesive film.

[0075] Example 4

[0076] 1. Preparation of Perovskite Quantum Dots (PQDs)

[0077] 1.1) Preparation of precursor A: Dissolve 0.05 mol Cs2CO3 in a mixed solvent of 65 ml ODE and 25 ml oleic acid, stir continuously and heat to 130°C under inert gas protection to completely dissolve the precursor A;

[0078] 1.2) Preparation of solution B: weigh 5 mmol PbCl2 and 5 mmol ZnCl2, add 50 ml oleic acid, 60 ml oleylamine and 70 ml 1-octadecene, stir and dissolve under inert gas protection and heat to 220°C for 30 min to obtain solution B;

[0079] 1.3) Preparation of quantum dots PQDs: 12 ml of precursor solution A was added to 180 ml of solution B, reacted for 45 seconds and then cooled to room temperature; methyl acetate was added to precipitate, centrifuged and washed three times, and a perovskite quantum dot solution with a mass fraction of 30% was prepared with hexane.

[0080] 2. Preparation of alkaline earth metal chloride solution

[0081] Dissolve 5 mmol of alkaline earth metal chloride CaCl2 in a certain amount of isopropanol and dissolve by ultrasonication to prepare a 20 g solution.

[0082] 3. Preparation of film

[0083] 3.1) Perovskite quantum dot colloid: 35g of perovskite quantum dot solution, 200g of POE colloid and 20g of CaCl2 solution were mixed at 110°C for 1.5h, then melt-extruded at 70°C and 80rpm for 2.0h, and finally granulated at 100°C to obtain perovskite quantum dot colloid;

[0084] 3.2) Preparation of adhesive film: Weigh 105 g of perovskite quantum dot particles, 1.2 g of vinyl triisopropoxy silane, 1 g of 1,1-di-tert-butyl peroxide-3,3,5-trimethylcyclohexane, 0.8 g of pentaerythritol triacrylate, 0.2 g of poly(4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol) succinate and 0.15 g of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate); mix them evenly, melt extrude them, and form them into films by a casting method. The temperature in the casting method film forming process is 80°C to obtain a perovskite quantum dot adhesive film.

[0085] Comparative Example 1

[0086] The difference from Example 1 is that in step 2, the corresponding alkaline earth metal chloride solution is not added.

[0087] Comparative Example 2

[0088] The difference from Example 2 is that in step 2, the corresponding alkaline earth metal chloride solution is not added.

[0089] Comparative Example 3

[0090] The difference from Example 3 is that in step 2, the corresponding alkaline earth metal chloride solution is not added.

[0091] Comparative Example 4

[0092] The difference from Example 4 is that in step 2, the corresponding alkaline earth metal chloride solution is not added.

[0093] Detection method:

[0094] The perovskite quantum dot adhesive films prepared in each example and comparative example were cut into 5 cm × 5 cm squares (such as Figure 2 As shown), the photoluminescence quantum yield was measured under the same temperature and humidity conditions, and the measurement was performed three times. The average value was taken for comparison and the following test data was obtained:

[0095] The test results are shown in Table 1:

[0096] Table 1

[0097]

[0098] From the photoluminescence quantum yield results in Table 1, it can be seen that alkaline earth metal chlorides are added to Examples 1-4, and the amount added gradually increases, and the quantum yield shows a trend of first increasing (Examples 1-3), indicating that with the addition of alkaline earth metal chlorides, the surface of the perovskite quantum dots can be effectively passivated and repaired; and with the further increase in the amount of alkaline earth metal chloride added, the quantum efficiency shows a downward trend (Example 4), indicating that excessive addition has caused a certain degree of distortion of the perovskite lattice, resulting in a certain degree of attenuation of the quantum yield. Comparative Examples 1-4 did not add alkaline earth metal chlorides. Compared with the films of Examples 1-4 that added alkaline earth metal chlorides, the quantum yields were 32%-41% lower, indicating that the addition of alkaline earth metal chlorides can effectively improve the quantum yield of the perovskite quantum dot films. Figure 1 As shown, a comparison spectrum of the photoluminescence quantum yield of the perovskite quantum dot film embodiment 3 and the comparative example 3 is given, and the change trend of the two can be intuitively seen.

[0099] The above embodiments are only preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the above embodiments, a person of ordinary skill in the art should understand that any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a light conversion encapsulation film for solar cells, characterized in that: The following steps are involved: S1. Preparation of perovskite quantum dots PQDs: dissolving Cs2CO3 in 1-octadecene and oleic acid to prepare precursor A; weighing a certain amount of PbCl2 and transition metal chloride and adding them to a mixed solvent of oleic acid, oleylamine and 1-octadecene to prepare solution B; heating to a specified temperature, adding precursor A to solution B, centrifuging the reaction solution through precipitation to obtain perovskite quantum dots PQDs, and dissolving with hexane to obtain a perovskite quantum dot solution; S2. preparing an alkaline earth metal chloride solution: dissolving a certain amount of alkaline earth metal chloride in a solvent to obtain an alkaline earth metal chloride solution; S3. Preparation of perovskite quantum dot encapsulation adhesive film: mixing the perovskite quantum dot solution, blank colloid particles and alkaline earth metal chloride solution, and obtaining perovskite quantum dot colloid particles by melt extrusion and granulation; mixing the perovskite quantum dot colloid particles with a coupling agent, a primary cross-linking agent, an auxiliary cross-linking agent, a light stabilizer and an antioxidant, and then melt-extruded, and obtaining the perovskite quantum dot adhesive film by cast film formation.

2. The method for preparing the light conversion encapsulation film for solar cells according to claim 1, characterized in that: In the step S1, the ratio of PbCl2 to transition metal chloride is (3-6) mmol: (3-6) mmol, and the ratio of the mixed solvent of oleic acid, oleylamine and 1-octadecene is (40-60) ml: (40-60) ml: (30-80) ml.

3. The method for preparing the light conversion encapsulation film for solar cells according to claim 1, characterized in that: In the step S1, the transition metal chloride is ZnCl2, MnCl2 or CoCl2.

4. The method for preparing the light conversion encapsulation film for solar cells according to claim 1, characterized in that: The dosage ratio of Cs2CO3, 1-octadecene and oleic acid is (0.03-0.08) mol: (60-80) ml: (10-30) ml, and the heating temperature is 120-180°C.

5. The method for preparing the light conversion encapsulation film for solar cells according to claim 1, characterized in that: In the step S1, the heating temperature T1 of solution B is 100-180° C., and the holding time t1 is 20-60 minutes; the reaction temperature T2 is 140-280° C., and the reaction time t2 is 20-60 minutes.

6. The method for preparing the light conversion encapsulation film for solar cells according to claim 1, characterized in that: In the step S1, the volume ratio of the precursor A to the solution B is (3-10): (90-97), the reaction time is 10-60 seconds; and the concentration of the perovskite quantum dot solution is 20-30%.

7. The method for preparing the light conversion encapsulation film for solar cells according to claim 1, characterized in that: In step S2, the ratio of alkaline earth metal chloride to solvent is (3-6) mmol: (10-30) ml, and the concentration is 0.1-0.6 mol / L; the alkaline earth metal chloride is MgCl2, CaCl2 or BaCl2; and the solvent is one of ethanol, methanol, isopropanol or ethyl acetate.

8. The method for preparing the light conversion encapsulation film for solar cells according to claim 1, characterized in that: In step S3, the mass ratio of the perovskite quantum dot solution, the blank colloid particles and the alkaline earth metal chloride solution is (5-8): (20-40): (3-5); the mixing conditions are a temperature of 20-120°C and a time of 0.2-2h; the melt extrusion conditions are a temperature of 50-200°C, a time of 0.2-2 hours, and a rotation speed of 20-80rpm; the granulation temperature is 80-150°C.

9. The method for preparing the light conversion encapsulation film for solar cells according to claim 1, characterized in that: In step S3, during the film casting process, the temperature is 70-150°C and the film thickness is 0.2-0.5 mm.

10. The method for preparing the light conversion encapsulation film for solar cells according to claim 1, characterized in that: In step S3, 80-105 parts of perovskite quantum dot colloid particles, 0.1-2 parts of coupling agent, 0.4-2 parts of main cross-linking agent, 0.4-2 parts of auxiliary cross-linking agent, 0.05-0.2 parts of light stabilizer and 0.05-0.2 parts of antioxidant are weighed and mixed and then melt-extruded.

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