Rare earth doped porous Si-Ti composite photovoltaic glass coating liquid and preparation method thereof

Abstract

The invention discloses a rare earth doped porous Si-Ti composite photovoltaic glass coating liquid and a preparation method thereof.The preparation method specifically comprises the steps that firstly, porous Si-Ti composite sol of a specific structure is prepared; then adding rare earth related substances for doping and hybrid cross-linking to form stable hybrid sol; diluting the hybrid sol, adjusting the pH value, and filtering to obtain a finished product coating solution; and finally, coating and curing the film layer to form a target film layer. The light transmittance of the prepared film layer in the wave band of 380-1100 nm is larger than 97%, the contact angle is smaller than 10 degrees, the light transmittance retention rate after 800 h ultraviolet aging is larger than 95%, and the film layer has the super-hydrophilic self-cleaning performance, the high weather resistance and the antistatic performance and can be widely applied to the fields of efficient photovoltaic modules, BIPV, flexible photovoltaic devices and the like.

Description

Technical Field

[0001] This application relates to the field of coating solution technology, specifically to a rare earth-doped porous Si-Ti composite photovoltaic glass coating solution and its preparation method. Background Technology

[0002] As the photovoltaic industry develops towards higher efficiency and longer lifespan, the performance of antireflective coating solutions on photovoltaic glass surfaces has become a key factor restricting module efficiency and reliability. Existing coating solution preparation technologies have the following shortcomings: On the one hand, while traditional silica-based coating solutions can reduce reflectivity, their low refractive index easily leads to insufficient short-wavelength light scattering, and their porous structure is easily corroded by vinyl acetate in EVA adhesive, resulting in unstable fluctuations in transmittance after long-term use, affecting module power generation efficiency. On the other hand, although titanium-based coating solutions have high refractive index and self-cleaning functions, they have significant weather resistance defects, and high crystallinity causes film defects that easily accelerate film aging, shortening module lifespan.

[0003] Furthermore, while doping with rare earth elements (such as La, Nd, and Ce) can enhance the optical properties and weather resistance of the coating solution by controlling energy levels, existing technologies mostly employ single rare earth doping or simple physical blending, resulting in uneven distribution of rare earth ions in the film layer. This makes it difficult to simultaneously achieve the dual goals of optimizing light absorption efficiency and enhancing interfacial adhesion. In terms of fabrication processes, the traditional sol-gel method relies on high-temperature treatment above 400℃ to form Si-O glass bonds, which can cause irreversible damage to flexible substrates such as polyimide. Atomic layer deposition technology, which can achieve nanoscale thickness control, is too expensive to meet the demands of large-scale production.

[0004] Based on this, this application proposes a rare earth-doped porous SiO2-TiO2 composite coating solution, which solves the current problems of coating solutions in terms of light transmittance, weather resistance and applicability through innovative material design and process optimization. Summary of the Invention

[0005] The purpose of this invention is to provide a coating solution optimized by rare earth doping and porous composite structure, which achieves a synergistic improvement in high light transmittance, superhydrophilic self-cleaning and weather resistance, and solves the technical bottlenecks of unstable light transmittance and poor weather resistance in existing coating solutions.

[0006] This application discloses a rare earth-doped porous Si-Ti composite photovoltaic glass coating solution, which is composed of the following raw materials in the indicated mass percentages: 15-25% porous Si-Ti composite sol, 0.5-3% rare earth dopant, 1-5% organic-inorganic hybrid crosslinking agent, 0.5-2% surfactant, and the balance being deionized water.

[0007] Preferably, the rare earth dopant is selected from La 3+ 、Nd3+ Er 3+ One or more of the following, and exists in the form of nitrate or acetylacetone salt; the porous Si-Ti composite sol has a particle size of 20-50 nm and has a hierarchical porous structure including macropores of 200-500 nm and micropores of <50 nm.

[0008] Preferably, the organic-inorganic hybrid crosslinking agent is a vinyl-containing hyperbranched polysiloxane, and the surfactant is a compound system of cationic emulsifier and nonionic emulsifier.

[0009] This application also provides a method for preparing a rare earth-doped porous Si-Ti composite photovoltaic glass coating solution, comprising the following steps:

[0010] Preparation of S1 porous Si-Ti composite sol: Tetrabutyl orthosilicate and tetrabutyl titanate were mixed in a molar ratio of 3:1, and ethanol and deionized water were added in a volume ratio of 1:1. Hydrochloric acid was used as a catalyst, and the mixture was stirred and hydrolyzed at 60°C for 2 hours. A template agent was added, and self-assembly was induced by solvent evaporation to form a sol with a hierarchical porous structure.

[0011] S2 rare earth doping and hybrid crosslinking: rare earth nitrates were dissolved in ethanol and added to the sol obtained in S1, and ultrasonically dispersed for 30 min; then organic-inorganic hybrid crosslinking agent and compound surfactant were added, and the crosslinking reaction formed a stable hybrid sol;

[0012] S3 post-treatment: Dilute the sol prepared in S2 with deionized water to a solid content of 8-12%, adjust the pH to 5-6, and filter to obtain the finished coating solution.

[0013] Preferably, in step S1, the template agent is a polyoxyethylene-polyoxypropylene-polyoxyethylene block copolymer, and the pH value of the hydrochloric acid is 2-3.

[0014] Preferably, the reaction conditions for the organic-inorganic hybrid crosslinking agent and the compound surfactant in step S2 are: reaction at 80°C for 3 to 6 hours.

[0015] The advantages of this invention are:

[0016] 1. The embodiments of the present invention utilize La 3+ 、Nd 3+ Er 3+ Co-doping with rare earth ions, utilizing their complementary energy level properties, broadens the light absorption range, and through the interaction of rare earth ions with Ti... 4+The interaction between the rare earth elements inhibits the phase transition of TiO2 from anatase to rutile, thereby improving the photothermal stability of the film. At the same time, the hierarchical porous network design—large pores of 200-500nm effectively enhance light scattering and anti-reflection properties, while pores of <50nm provide a high specific surface area, promoting the uniform distribution and light capture of rare earth ions, and synergistically improving light transmittance and self-cleaning properties, ultimately enabling the film to achieve a light transmittance of over 97% in the 380-1100nm wavelength band.

[0017] 2. In this embodiment of the invention, the oxygen vacancies induced by rare earth elements and the porous structure work synergistically to endow the film with superhydrophilicity and a contact angle of <10°, enabling it to achieve self-cleaning function; the chemical bonding network formed by SiO2-TiO2-rare earth elements can significantly enhance structural stability, and the transmittance retention rate is >95% after 800h of ultraviolet aging, showing excellent environmental durability.

[0018] 3. The environmentally friendly water-based fluorine-free sol system of the present invention is compatible with low-temperature roller coating process and has a pre-curing temperature of <150℃, which avoids damage to flexible substrates caused by high temperature. It can be adapted to large-scale production and meet the various application requirements of high-efficiency photovoltaic modules, BIPV architectural glass and flexible photovoltaic devices. Detailed Implementation

[0019] The technical solutions in the embodiments of the present invention will be described in detail below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Example 1

[0021] Preparation of S1 porous Si-Ti composite sol: Tetrabutyl orthosilicate and tetrabutyl titanate were mixed in a molar ratio of 3:1, ethanol and deionized water (volume ratio 1:1) were added, the pH was adjusted to 2.5 with hydrochloric acid, and the mixture was stirred and hydrolyzed at 60℃ for 2 h to form Si-Ti sol; template agent P123 was added at 5% of the sol mass to form a hierarchical porous structure. The pore size of the macropores inside the sol was concentrated in 250-420 nm, the pore wall thickness was about 30-50 nm, and micropores with a pore size of 20-30 nm were uniformly distributed on the pore walls.

[0022] S2 Rare Earth Doping and Hybrid Crosslinking: 1.5% of La(NO3)3·6H2O by mass of the sol was dissolved in ethanol and added to the S1 sol, and ultrasonically dispersed for 30 min; then 3% of vinyl-containing hyperbranched polysiloxane and 1.2% of compound surfactant by mass of the sol were added, and the crosslinking reaction was carried out at 80℃ for 4 h to form a stable hybrid sol; using vinyl-containing hyperbranched polysiloxane as a crosslinking agent, its branched structure can enhance the network density and mechanical strength of the film layer, and the vinyl functional groups can form coordination bonds with rare earth ions, further improving the stability of the film layer.

[0023] S3 post-treatment: The sol prepared in S2 was diluted with deionized water to a solid content of 10%, the pH was adjusted to 5.5, and the solution was filtered through a 0.22 μm filter membrane to obtain the La-doped coating solution.

[0024] Example 2

[0025] In step S2 of Example 1, the phrase "1.5% of the sol mass of La(NO3)3·6H2O" was adjusted to "La(NO3)3·6H2O and Nd(NO3)3·6H2O were mixed at a mass ratio of 1:1, and the total doping amount accounted for 2% of the sol mass". The rest remained the same as in Example 1, and a La-Nd co-doped coating solution was prepared.

[0026] Example 3

[0027] In step S2 of Example 2, the phrase "La(NO3)3·6H2O and Nd(NO3)3·6H2O are mixed in a 1:1 mass ratio, with the total doping amount accounting for 2% of the sol mass" is adjusted to "La(NO3)3·6H2O and Nd(NO3)3·6H2O are mixed in a 2:1 mass ratio, with the total doping amount accounting for 2.5% of the sol mass". The rest remains the same as in Example 2, thus obtaining the La-Nd co-doped coating solution.

[0028] Example 4

[0029] The step S2 in Example 1, which was "1.5% of the sol mass of La(NO3)3·6H2O was dissolved in ethanol and added to the sol in S1, and ultrasonically dispersed for 30 min; then 3% of the sol mass of vinyl-containing hyperbranched polysiloxane and 1.2% of the sol mass of compound surfactant were added, and the crosslinking reaction was carried out at 80°C for 4 h to form a stable hybrid sol," was changed to "2.5% of the sol mass of Er(NO3)3·6H2O was dissolved in ethanol and added to the sol in S1, and ultrasonically dispersed for 30 min; then 4% of the sol mass of vinyl-containing hyperbranched polysiloxane and 1.5% of the sol mass of compound surfactant were added, and the crosslinking reaction was carried out at 80°C for 5 h to form a stable hybrid sol." The rest of the steps remained the same as in Example 1, and an Er-doped coating solution was prepared.

[0030] Example 5

[0031] Step S2 in Example 4 was modified to "mix La(NO3)3·6H2O and Er(NO3)3·6H2O at a mass ratio of 1:1, with a total doping amount of 2.2% of the sol mass, dissolve in ethanol and add to the sol in S1, and ultrasonically disperse for 30 min; then add 3.2% of vinyl-containing hyperbranched polysiloxane and 1.3% of compound surfactant, accounting for 1.3% of the sol mass, and react at 80°C for 4.5 h to form a stable hybrid sol", with the rest remaining the same as in Example 4, to obtain the La-Er co-doped coating solution.

[0032] The coating solutions prepared in Examples 1-5 were applied to the surface of photovoltaic glass using a roller coating process. Film coating and curing were then performed to form the target film layer on the substrate surface. Corresponding tests were conducted, and the results are as follows:

[0033]

[0034]

[0035] In summary, the synergistic design of rare-earth co-doping and hierarchical porous structure, combined with organic-inorganic hybrid crosslinking technology, successfully prepared a photovoltaic glass coating solution with the following comprehensive properties:

[0036] (1) Due to the light scattering of the porous structure and the energy level regulation of rare earth ions, the average transmittance of the coating solution in the 380-1100nm band is >97%, thus achieving high transmittance of the coating solution.

[0037] (2) Due to the synergistic effect of rare earth-induced oxygen vacancies and porous structure, the contact angle of the coating solution is <10°, achieving superhydrophilicity and self-cleaning properties.

[0038] (3) Due to the stable chemical bonding network formed by Si-O-Ti-RE, the transmittance of the coating solution is maintained at >95% after 800h of UV aging.

[0039] (4) The combined use of crosslinking agent and surfactant enhances the density and adhesion of the film layer, improves the antistatic properties and mechanical temperature properties of the coating solution, and the coating solution can be widely used in the fields of high-efficiency photovoltaic modules, BIPV building glass and flexible photovoltaic devices.

[0040] This embodiment is merely an illustrative description of the present patent and does not limit its scope of protection. Those skilled in the art may make partial modifications to it. As long as they do not exceed the spirit and essence of the present patent, they shall be regarded as equivalent substitutions to the present patent and shall be within the scope of protection of the present patent.

Claims

1. A rare earth-doped porous Si-Ti composite photovoltaic glass coating solution, characterized in that, It is composed of the following raw materials in the following mass percentages: 15-25% porous Si-Ti composite sol, 0.5-3% rare earth dopant, 1-5% organic-inorganic hybrid crosslinking agent, 0.5-2% surfactant, and the balance deionized water.

2. The rare earth-doped porous Si-Ti composite photovoltaic glass coating solution according to claim 1, characterized in that, The rare earth dopant is selected from La 3+ 、Nd 3+ Er 3+ One or more of the following, and exists in the form of nitrate or acetylacetone salt; the porous Si-Ti composite sol has a particle size of 20-50 nm and has a hierarchical porous structure including macropores of 200-500 nm and micropores of <50 nm.

3. The rare earth-doped porous Si-Ti composite photovoltaic glass coating solution according to claim 1, characterized in that, The organic-inorganic hybrid crosslinking agent is a vinyl-containing hyperbranched polysiloxane, and the surfactant is a mixed compound system of cationic emulsifier and nonionic emulsifier.

4. A method for preparing a coating solution as described in any one of claims 1-3, characterized in that, Includes the following steps: Preparation of S1 porous Si-Ti composite sol: Tetrabutyl orthosilicate and tetrabutyl titanate were mixed in a molar ratio of 3:1, and ethanol and deionized water were added in a volume ratio of 1:

1. Hydrolysis was carried out at 60°C for 2 hours with hydrochloric acid as a catalyst. A template agent was added to form a sol with a hierarchical porous structure. S2 Rare Earth Doping and Hybrid Crosslinking: Rare earth nitrates are dissolved in ethanol and added to the sol of S1, and ultrasonically dispersed for 30 min; then organic-inorganic hybrid crosslinking agent and compound surfactant are added, and the crosslinking reaction forms a stable hybrid sol; S3 Post-treatment: Dilute the sol prepared in S2 with deionized water to a solid content of 8-12%, adjust the pH to 5-6, and filter to obtain the finished coating solution.

5. The method for preparing the rare earth-doped porous Si-Ti composite photovoltaic glass coating solution according to claim 4, characterized in that, In step S1, the template agent is a polyoxyethylene-polyoxypropylene-polyoxyethylene block copolymer, and the hydrochloric acid has a pH value of 2-3.

6. The method for preparing the rare earth-doped porous Si-Ti composite photovoltaic glass coating solution according to claim 4, characterized in that, The reaction conditions for the organic-inorganic hybrid crosslinking agent and the compound surfactant in step S2 are: reaction at 80°C for 3 to 6 hours.

7. The method for preparing the rare earth-doped porous Si-Ti composite photovoltaic glass coating solution according to claim 1, characterized in that, The coating solution is used in photovoltaic glass or BIPV.

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