CN112876896B

CN112876896B - Rare earth metal organic complex coated zinc oxide titanium nano sol and preparation method thereof

Info

Publication number: CN112876896B
Application number: CN202110101562.5A
Authority: CN
Inventors: 林建伟; 张付特; 孙海龙
Original assignee: JOLYWOOD (SUZHOU) SUNWATT CO Ltd
Current assignee: JOLYWOOD (SUZHOU) SUNWATT CO Ltd
Priority date: 2021-01-26
Filing date: 2021-01-26
Publication date: 2022-05-17
Anticipated expiration: 2041-01-26
Also published as: CN112876896A

Abstract

The invention relates to a rare earth metal organic complex coated zinc oxide titanium nano sol and a preparation method thereof, wherein the preparation method comprises the following steps: adding a zinc precursor and a titanium precursor into a reaction solvent, stirring, and uniformly mixing to obtain a mixed solution; dropwise adding a catalyst aqueous solution into the mixed solution, and preparing zinc oxide titanium nanoparticles through a sol-gel reaction; performing ultra-dispersion on the zinc oxide titanium nano particles, and then performing surface modification; and step four, adding the rare earth metal organic complex, continuing to react and drying to obtain the rare earth metal organic complex coated zinc oxide titanium nano sol with excellent transparency, down-conversion function and ultraviolet cut-off function. After the prepared zinc oxide titanium nano sol wrapped by the rare earth metal organic complex is added into the coating for the solar cell back plate, the service life of the solar cell panel can be prolonged, and the utilization rate of the solar cell panel to solar energy is improved.

Description

Rare earth metal organic complex coated zinc oxide titanium nano sol and preparation method thereof

Technical Field

The invention belongs to the technical field of organic-inorganic hybrid nano materials, and particularly relates to a rare earth metal organic complex coated zinc oxide titanium nano sol and a preparation method thereof.

Background

Nowadays, with the daily exhaustion of traditional energy sources such as petroleum and coal, the environmental pollution is becoming more serious, and solar energy as a novel clean energy source is getting more and more attention. In order to improve the return on investment in power generation of the solar cell panel, the solar cell panel is required to have a longer service life. The solar cell panel is generally a laminated structure and mainly comprises a glass surface layer, an EVA sealing layer, a solar cell sheet, an EVA sealing layer and a solar cell back plate, wherein the solar cell sheet is hermetically wrapped by the two EVA sealing layers. The solar cell backboard mainly has the effects of improving the overall mechanical strength of the solar cell panel and preventing water vapor from penetrating into the EVA sealing layer to influence the service life of the solar cell. Therefore, the solar cell backboard plays a crucial role in prolonging the service life of the solar cell panel. Therefore, the key to prolonging the service life of the solar cell panel is to improve the weather resistance and the aging resistance of the solar cell back panel.

Wherein, the light wave range of the sunlight is between 290-3000nm, the visible light band of 400-800nm accounts for 40% of the total energy of the sunlight, the infrared light band of 800-3000nm accounts for 55%, and the ultraviolet light band of 280-400 accounts for 5%. However, the ultraviolet light can greatly damage the solar cell back plate, and the service life of the solar cell panel is seriously influenced. One important function of the solar cell back sheet is to protect the solar cell panel by absorbing this part of the ultraviolet light. In the current method, for example, in the invention CN110885593A, an organic ultraviolet absorbent is added into a coating for a solar cell back panel, so that part of ultraviolet light with high energy and harmful to resins for a photovoltaic back panel, such as acrylic resin and polyurethane resin, is absorbed, and the absorbed ultraviolet light is released in the form of heat energy, so that the degradation speed of the resins for a photovoltaic back panel, such as acrylic resin and polyurethane resin, is greatly slowed down, and the service life of a solar cell panel is prolonged. On the one hand, however, the release of the absorbed ultraviolet light in the form of heat energy causes energy waste, reducing the energy utilization rate; on the other hand, the organic ultraviolet absorbent is still easy to yellow or degrade after a long time, and further the service life of the coating and the solar cell panel is influenced.

Disclosure of Invention

One of the purposes of the invention is to overcome the defects of the prior art and provide a preparation method of a rare earth metal organic complex coated zinc titanium oxide nano sol, and after the prepared rare earth metal organic complex coated zinc titanium oxide nano sol is added into a coating for a solar cell back panel, the service life of a solar cell panel can be prolonged, and the utilization rate of the solar cell panel on solar energy can be improved.

The second purpose of the invention is to overcome the defects of the prior art and provide the rare earth metal organic complex coated zinc oxide titanium nano sol with excellent transparency, down-conversion function and ultraviolet cut-off function.

Based on the above, the invention discloses a preparation method of a rare earth metal organic complex coated zinc oxide titanium nano sol, which comprises the following steps:

adding a zinc precursor and a titanium precursor into a reaction solvent, stirring, and uniformly mixing to obtain a mixed solution;

dropwise adding a catalyst aqueous solution into the mixed solution, reacting while stirring, heating, and reacting to generate zinc oxide titanium nano particles;

dispersing the zinc oxide titanium nano particles by ultrasonic, adding a surface modifier, and stirring to modify the surfaces of the zinc oxide titanium nano particles;

and step four, adding the rare earth metal organic complex into the zinc oxide titanium nano particles with the modified surfaces, continuing to react, and drying to obtain the zinc oxide titanium nano sol coated by the rare earth metal organic complex.

The rare earth metal organic complex coated zinc oxide titanium nano sol prepared by the invention is a nano particle synthesized by a sol-gel method, and is restricted by a plurality of factors in the process of forming the nano particle: such as reaction time, reaction temperature, reactant concentration, pH of the reaction system, activity and concentration of the catalyst, etc.; these factors play an important role in the particle size, uniformity and dispersibility of the nanoparticles; and the mixed solution contains two metal precursors at the same time, so that the two metal precursors form the metal alloy oxide at the same time, and the proportion of the two metal oxide precursors needs to be regulated and controlled. Furthermore, the surface properties of the nanoparticles are also related to the rare earth metal organic complexes. Therefore, in order to promote the synthesized zinc oxide titanium nano sol coated by the rare earth metal organic complex to have excellent transparency, down-conversion function and ultraviolet cut-off function, the above various factors need to be further adjusted, specifically as follows:

in the first step, the zinc precursor is an organic zinc source or an inorganic zinc source; the organic zinc source is zinc acetylacetonate, diethyl zinc, zinc acetate or other organic zinc sources; the inorganic zinc source is one or more of zinc sulfate, zinc chloride, zinc acetate and zinc nitrate. Preferably, the zinc precursor is zinc acetate or zinc nitrate with better solubility.

In the first step, the titanium precursor is an organic titanium source or an inorganic titanium source; the organic titanium source is one or more of tetraethoxy titanium, tetraisopropoxy titanium and tetrabutoxy titanium; the inorganic titanium source is one or more of titanium chloride, titanium sulfate and titanyl sulfate. Preferably, the titanium precursor is an organotitanium source, more preferably, titanium tetraisopropoxide or titanium tetrabutoxide, to ensure a moderate hydrolysis rate of the titanium precursor.

In the first step, the reaction solvent is one or more of lower alcohol (such as methanol, ethanol, propanol, isopropanol, butanol and isobutanol) of C1-C5, higher alcohol (such as polyvinyl alcohol and hexanediol) and a mixed solution of water and alcohol. Preferably, the reaction solvent is a mixture of anhydrous ethanol and isopropanol with low boiling point, which is convenient for subsequent drying.

In the first step, the titanium precursor and the zinc precursor are added into the reaction solvent to generate a strong exothermic reaction, and at this time, vigorous stirring or stirring under a low temperature condition (such as stirring in an ice water bath) is required to control the subsequent reaction temperature.

In the first step, when the reaction solvent is 100 parts by weight, the sum of the weight of the titanium precursor and the weight of the zinc precursor is 1-30 parts; the weight ratio of the titanium precursor to the zinc precursor is 0.1-10. Preferably, when the reaction solvent is 100 parts by weight, the sum of the weight of the titanium precursor and the weight of the zinc precursor is 20-28 parts, and the weight ratio of the zinc precursor to the titanium precursor is 1: 1.3-5.

In the second step, the catalyst aqueous solution is obtained by uniformly mixing the catalyst, absolute ethyl alcohol and water, and the catalyst aqueous solution is an acidic catalyst aqueous solution or a basic catalyst aqueous solution. When the acid catalyst aqueous solution is adopted, the pH value of the mixed solution needs to be adjusted to 1-3; when an alkaline catalyst aqueous solution is adopted, the pH value of the mixed solution needs to be adjusted to 8-10, and at the moment, the catalyst is ammonia water or tetramethyl ammonium hydroxide; thus, the titanium precursor and the zinc precursor are gradually hydrolyzed to form zinc titanium oxide nanoparticles. Preferably, if the amount of water added to the reaction system is too large, the titanium precursor is hydrolyzed too quickly, and the particle size of the generated zinc oxide titanium nanoparticles is large, and if the aqueous solution of the basic catalyst is added to the mixed solution, the rate of forming the sol is too fast, and the zinc oxide titanium nanoparticles are also likely to have a large particle size; therefore, in the second step, in order to control and obtain more uniform and highly dispersed zinc titanium oxide nanoparticles, it is preferable to use an acidic catalyst aqueous solution, because the hydrolysis rate of the titanium precursor and the zinc precursor is slower under acidic conditions, and nano-scale particles are more easily formed. When an acidic catalyst aqueous solution is used, the catalyst is one or more of nitric acid, hydrochloric acid, oxalic acid, sulfuric acid and acetic acid, preferably hydrochloric acid or nitric acid, and more preferably hydrochloric acid, so that the particles of the generated zinc titanium oxide nanoparticles are more uniform and stable.

In the second step, the reaction time is controlled to be 12-36h, preferably, the reaction is carried out for 24h while stirring, and after the temperature is raised, the reaction is carried out for 2h to obtain the yellowish or micro-emulsion white zinc-titanium oxide nano particles.

Wherein, in the second step, the temperature rise is 30-80 ℃, preferably 80 ℃, so that the generated zinc oxide titanium nano particles are more stable.

Wherein, if the reaction system uses low boiling point organic solvent (such as methanol, ethanol, isopropanol, etc.), a cooling reflux device can be used to avoid the agglomeration of particles caused by quick and clean volatilization of the solvent. In order to further improve the dispersibility of the zinc oxide titanium nanoparticles, a surfactant can be added into the reaction system after the temperature is raised to a specified temperature. The surfactant is a cationic surfactant, an anionic surfactant or a neutral surfactant. Preferably, the surfactant is preferably sodium dodecylbenzene sulfonate, cetyltrimethylammonium bromide, cetyltrimethylammonium chloride, dodecyltrimethylammonium bromide, polyvinylpyrrolidone. The weight of the surfactant is 0.1-10%, preferably 0.5-1% of the weight of the zinc oxide titanium nanoparticles. If the amount of the surfactant is too small, the dispersion effect cannot be achieved, and if the amount of the surfactant is too large, a strong steric hindrance effect is brought to the next coating, so that the preparation of the zinc oxide titanium nano sol coated by the rare earth metal organic complex is influenced.

Wherein, in the third step, the time of ultrasonic dispersion is controlled within 1-10min, preferably 2-3 min. Preferably, the ultrasonic dispersion device is an ultrasonic machine or a cell crusher.

In the third step, the surface modifier is a silane coupling agent, an organic solvent with bifunctional groups or tert-butylamine; the silane coupling agent is vinyl tri-tert-butyl peroxy silane, methyl tri-tert-butyl peroxy silane, vinyl methyl di-tert-butyl silane, 3-aminopropyl trimethoxy silane, a silane coupling agent KH550, a silane coupling agent KH560, a silane coupling agent KH570, a silane coupling agent KH151, a silane coupling agent KH171 or a silane coupling agent KH 602; the organic solvent with bifunctional groups is terephthalic acid, p-phenylenediamine, p-mercaptobenzoic acid or mercaptoacetic acid. Preferably, the surface modifier is 3-aminopropyltrimethoxysilane or tert-butylamine.

In the fourth step, the rare earth metal organic complex is one or more of organic complexes of ytterbium, europium, erbium, cerium, terbium, praseodymium and neodymium; preferably ytterbium or europium. Preferably, the rare earth metal organic complex is obtained by reacting rare earth inorganic salt with an organic complex; the rare earth inorganic salt is preferably any two of inorganic salts of ytterbium, europium, cerium and neodymium; the inorganic salt is nitrate, chloride or sulfate; in order to stabilize the inorganic metal salt, organic complex is added, wherein the organic complex is polydentate ligand (such as ethylene diamine tetraacetic acid, hexamethylene tetramine, ethylene diamine and glycine), monodentate ligand (namely C2-C18 organic compound containing amino, carboxyl, sulfydryl and other groups, such as oleic acid, octadecenoic acid, octylamine and sulfydryl acetic acid), ligand containing active groups at two ends, silane coupling agent, acetylacetone or bipyridyl. Preferably, the organic complex is a polydentate ligand, a monodentate ligand, acetylacetone, or a silane coupling agent such as gamma- (2, 3-glycidoxy) propyltrimethoxysilane.

In the fourth step, the weight of the rare earth metal in the rare earth metal organic complex is 0.1-10% of the weight of the zinc oxide titanium nano particles, and the weight of the organic complex is 1-30% of the weight of the zinc oxide titanium nano particles; preferably, the temperature for the continuous reaction is 80 ℃ and the time is 5 h.

Wherein, in the fourth step, the drying mode is normal pressure drying, vacuum drying or freeze drying. Preferably, the drying mode is freeze drying at 180-0 ℃ to play a role of redispersion, so that the zinc oxide titanium nano sol coated by the rare earth metal organic complex is not easy to agglomerate.

After the fourth step, the method further comprises the following steps: dispersing the dried zinc oxide titanium nano sol coated by the rare earth metal organic complex in a spreading solvent, and facilitating subsequent sale or adding into a coating. According to specific needs, the dried zinc oxide titanium nano sol wrapped by the rare earth metal organic complex is dispersed in a spreading solvent to obtain a solution with the solid content of 5-40 wt%, and when the solution is used, the solution is mixed into resins for photovoltaic back panels such as acrylic resin, fluorocarbon resin and polyimide, or the solution can be added into a coating for solar cell back panels.

Wherein the spreading solvent is one or more of methyl acetate, ethyl acetate, isopropyl acetate, N-butyl acetate, cellosolve acetate, N dimethylformamide, N-methylpyrrolidine dione, tetrahydrofuran, propylene glycol monomethyl ether, hexanediol, acetylacetone and propylene glycol methyl ether acetate. Preferably, the spreading solvent is ethylene glycol monomethyl ether or propylene glycol methyl ether acetate.

The invention also discloses the zinc oxide titanium nano sol coated by the rare earth metal organic complex and prepared by the preparation method, wherein the zinc oxide titanium nano sol has excellent transparency, down-conversion function and ultraviolet cut-off function.

Compared with the prior art, the invention at least comprises the following beneficial effects:

according to the preparation method disclosed by the invention, referring to fig. 1, zinc titanium oxide nanoparticles are generated through a sol-gel reaction, and then rare earth metal is coated on the surfaces of the zinc titanium oxide nanoparticles through the chelation of an organic complex, so that the rare earth metal and the zinc titanium oxide nanoparticles are combined in a chemical bond form, and the zinc titanium oxide nanosol coated by the rare earth metal organic complex with a more stable structure is obtained.

The zinc oxide titanium nano sol wrapped by the rare earth metal organic complex is of a core-shell structure. The shell is a rare earth metal organic complex with a down-conversion function, and can convert ultraviolet light into usable visible light and near infrared light, so that energy waste caused by the fact that an organic ultraviolet absorbent releases the absorbed ultraviolet light in a heat energy form can be effectively avoided, the transmittance of the visible light and the near infrared light can be improved, after the prepared zinc oxide titanium nano sol wrapped by the rare earth metal organic complex is added into the coating for the solar cell backboard, the solar energy utilization rate can be improved, the temperature of a solar cell panel can be reduced, and the solar cell panel can be protected; the inner core is the zinc oxide titanium nano particles with the high ultraviolet cut-off function, so the zinc oxide titanium nano particles can absorb ultraviolet light which is not completely converted by the shell, the solar cell panel can be better protected from being damaged by ultraviolet light, and the inorganic ultraviolet absorbent is more stable and reliable than the organic ultraviolet absorbent. Moreover, the zinc oxide titanium nano sol coated by the rare earth metal organic complex prepared by the invention also has excellent compatibility with an organic solvent, storage stability and monodispersity; therefore, the zinc oxide titanium nano sol coated by the rare earth metal organic complex can be dispersed in the coating for the solar cell back panel at high concentration, and can be easily redispersed in an organic solvent without damaging the transparency of the organic solvent and the coating, so that the rare earth metal organic complex has the characteristic of high transparency. Therefore, the rare earth metal organic complex coated zinc oxide titanium nano sol is added into the coating for the solar cell back plate, so that the solar energy utilization rate can be improved, the generated energy of the solar cell panel can be improved, the yellowing of the solar cell back plate can be effectively reduced, the solar cell panel can be well protected, and the service life of the solar cell panel can be prolonged.

In addition, the rare earth metal organic complex coated zinc oxide titanium nano sol can be used for the coating for the solar cell back panel and can also be used in the fields of high-transparency glasses and the like.

Drawings

FIG. 1 is a schematic diagram of the preparation of the rare earth metal organic complex coated zinc oxide titanium nano sol of the present invention.

FIG. 2 is an SEM image of a rare earth metal organic complex coated zinc titanium oxide nanosol prepared in example 1.

FIG. 3 is an SEM image of a rare earth metal organic complex coated zinc titanium oxide nanosol prepared in example 2.

FIG. 4 is an SEM image of a rare earth metal organic complex coated zinc titanium oxide nanosol prepared in example 3.

FIG. 5 is an SEM image of a rare earth metal organic complex coated zinc titanium oxide nanosol prepared in example 4.

FIG. 6 is a transmission spectrum of a coating layer of a rare earth metal organic complex-coated zinc titanium oxide nanosol prepared in example 4.

Fig. 7 is a transmission spectrum of a coating layer of the titania-organic complex sol prepared in comparative example 1.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.

Example 1

The preparation method of the rare earth metal organic complex coated zinc oxide titanium nano sol of the embodiment is as follows:

adding 250g of absolute ethyl alcohol into a reactor, slowly adding 40g of isopropanol into the absolute ethyl alcohol, then adding 20g of zinc acetate, stirring to dissolve, adding 60g of titanium tetraisopropoxide, and stirring for 30min to obtain a reaction solution. Uniformly mixing 18mL of water, 15mL of hydrochloric acid and 70mL of anhydrous ethanol, slowly dripping the mixture into the reaction solution, stirring the mixture for 24 hours, heating the mixture to 80 ℃, reacting the mixture for 2 hours, then adding 3mL of 3-aminopropyltrimethoxysilane, stirring the mixture for 12 hours, centrifugally precipitating the mixture, adding anhydrous ethanol and isopropanol to dissolve the mixture, then adding 0.5g of europium nitrate and 0.5g of ytterbium nitrate, reacting the mixture for 2 hours at the temperature of 80 ℃, adding 20g of hexamethylenetetramine, and reacting the mixture for 5 hours at the temperature of 80 ℃; after cooling to room temperature, lyophilization and drying are carried out for 24h, and Zn (x) Ti (y) O (x +2y): yb of³⁺-Eu³⁺An organic complex powder. Reacting Zn (x) Ti (y) O (x +2y): yb of³⁺-Eu³⁺And cooling the organic complex powder to room temperature, and adding 150g of ethylene glycol monomethyl ether solvent to obtain the redispersed rare earth metal-coated zinc oxide titanium-organic complex sol.

Example 2

adding 250g of absolute ethyl alcohol into a reactor, slowly adding 40g of isopropanol into the absolute ethyl alcohol, adding 30g of zinc nitrate, stirring to dissolve, then adding 40g of titanium tetrabutoxide, and stirring for 30min to obtain a reaction solution. Uniformly mixing 18mL of water, 15mL of hydrochloric acid and 70mL of absolute ethyl alcohol, slowly dripping into the reaction solution, stirring for 24 hours, heating to 80 ℃, reacting for 2 hours, then adding 3mL of 3-aminopropyltrimethoxysilane, stirring for 12 hours, centrifugally precipitating, adding absolute ethyl alcohol and isopropanol to dissolve, then adding 0.6g of neodymium nitrate and 1g of ytterbium nitrate, reacting for 2 hours at 80 ℃, then adding 20 parts of acetylacetone, and reacting for 5 hours at 80 ℃; cooling to room temperature, lyophilizing for 24h to obtain Zn (x) Ti (y) O (x +2y): Nd³⁺-Yb³⁺An organic complex powder. Zn (x) Ti (y) O (x +2y) Nd³⁺-Yb³⁺And cooling the organic complex powder to room temperature, and adding 150g of ethylene glycol monomethyl ether solvent to obtain the redispersed rare earth metal-coated zinc oxide titanium-organic complex sol.

Example 3

adding 250g of absolute ethyl alcohol into a reactor, slowly adding 40g of isopropanol into the absolute ethyl alcohol, adding 30g of zinc nitrate, stirring to dissolve, then adding 40g of titanium tetrabutoxide, and stirring for 30min to obtain a reaction solution. Uniformly mixing 18mL of water, 15mL of hydrochloric acid and 70mL of absolute ethyl alcohol, slowly dripping into the reaction solution, stirring for 24h, heating to 80 ℃, reacting for 2h, then adding 3mL of tert-butylamine, stirring for 12h, centrifuging, precipitating, adding absolute ethyl alcohol and isopropanol, dissolving, then adding 0.5g of ytterbium nitrate and 1g of cerium nitrate, reacting for 2h at 80 ℃, then adding 20g of adipic acid, and reacting for 5h at 80 ℃; cooling to room temperature, lyophilizing for 24h to obtain Zn (x) Ti (y) O (x +2y) Ce³⁺-Yb³⁺An organic complex powder. Zn (x) Ti (y) O (x +2y) Ce³⁺-Yb³⁺The organic complex powder was cooled to room temperature, and 150g of the organic complex powder was addedPropylene glycol methyl ether acetate solvent to obtain re-dispersed rare earth metal coated zinc oxide titanium-organic complex sol.

Example 4

adding 250g of absolute ethyl alcohol into a reactor, slowly adding 40g of isopropanol into the absolute ethyl alcohol, adding 10g of zinc nitrate, stirring to dissolve, then adding 50g of titanium tetrabutoxide, and stirring for 30min to obtain a reaction solution. Uniformly mixing 20mL of water, 15mL of hydrochloric acid and 70mL of absolute ethyl alcohol, slowly dripping into the reaction solution, stirring for 24 hours, heating to 80 ℃, and reacting for 2 hours; adding 2mL of 3-aminopropyltrimethoxysilane, stirring for 12h, centrifugally precipitating, adding absolute ethanol and isopropanol to dissolve, adding 0.5g of europium nitrate and 1g of cerium nitrate to react for 2h at 80 ℃, adding 30g of gamma- (2, 3-glycidoxy) propyltrimethoxysilane to react for 5h at 80 ℃; cooling to room temperature, lyophilizing for 24h to obtain Zn (x) Ti (y) O (x +2y) Ce³⁺-Eu³⁺An organic complex powder. Zn (x) Ti (y) O (x +2y) Ce³⁺-Eu³⁺The organic complex powder was cooled to room temperature, and 150g of propylene glycol methyl ether acetate solvent was added to obtain a re-dispersed rare earth metal-coated zinc oxide titanium-organic complex sol.

Comparative example 1

The preparation method of the titanium oxide-organic complex sol of the comparative example was as follows:

250g of absolute ethanol was added to the reactor, 40g of isopropyl alcohol was slowly added to the absolute ethanol, and after stirring and dissolution, 60g of titanium tetrabutoxide was added and stirred for 30min to obtain a reaction solution. Uniformly mixing 20mL of water, 18mL of hydrochloric acid and 70mL of absolute ethyl alcohol, slowly dripping into the reaction solution, stirring for 24 hours, heating to 80 ℃, and reacting for 2 hours; adding gamma- (2, 3-epoxypropoxy) propyl trimethoxy silane, and stirring for 12 h; cooling to room temperature, freeze-drying for 24h to obtain TiO₂An organic complex powder. Adding TiO into the mixture₂The organic complex powder was cooled to room temperature, and 200g of propylene glycol methyl ether acetate solvent was added to obtain a titanium oxide-organic complex sol.

Comparative example 2

The preparation method of the zinc oxide titanium sol of the comparative example is as follows:

adding 250g of absolute ethyl alcohol into a reactor, slowly adding 40g of isopropanol into the absolute ethyl alcohol, adding 10g of zinc acetate, stirring to dissolve, then adding 50g of titanium tetrabutoxide, and stirring for 30min to obtain a reaction solution. Uniformly mixing 20mL of water, 15mL of hydrochloric acid and 70mL of anhydrous methanol, slowly dripping into the reaction solution, stirring for 24h, heating to 80 ℃, and reacting for 2 h; then 2mL of gamma- (2, 3-epoxypropoxy) propyl trimethoxy silane is added and stirred for 12h, thus obtaining the product.

Performance testing

1. The scanning electron microscope test of the rare earth metal organic complex coated zinc oxide titanium nano sol of the examples 1 to 4 is performed, and the test results are shown in fig. 2 to 5, and it can be seen that the preparation methods of the examples 1 to 4 can successfully prepare the nano-sized rare earth metal organic complex coated zinc oxide titanium nano sol.

2. The transmission spectrum test was performed on the blank PET film, and the sol coatings of examples 1 to 4 and comparative examples 1 to 2, and the test results are shown in table 1 and fig. 6 to 7.

TABLE 1

Light transmittance T%	Optical wavelength of 280-380nm	Optical wavelength 380-
			Blank PET	40.11	87.89
Example 1	5.87	92.85
			Example 2	4.55	93.25
Example 3	5.10	93.20
			Example 4	5.4	93.7
Comparative example 1	39.2	92.0
			Comparative example 2	13.24	90.52

As can be seen from table 1 and fig. 6 to 7, the sol coating of comparative example 1 has a poor uv cut function, and its uv transmittance is only slightly lower than that of the blank PET film, while the sol coating of comparative example 2 has a uv cut function superior to that of comparative example 1, but its uv cut function is still lower than that of the sol coatings of examples 1 to 4; while the transmittance of visible light and near infrared light is superior to that of comparative example 2 for the sol coating of comparative example 1, the transmittance of visible light and near infrared light is lower than that of examples 1 to 4 for the sol coatings of comparative examples 1 to 2. It can be seen that the sol coatings of examples 1-4 have both an excellent down-conversion function, which can improve the transmittance of visible light and near-infrared light, and thus the solar cell panel's utilization of solar energy, and an excellent ultraviolet cut-off function, which can better protect the solar cell panel from ultraviolet damage, compared to the sol coatings of comparative examples 1-2.

3. The sol coatings of examples 1-4 and comparative examples 1-2 were tested for yellowing resistance with reference to GB/T7921-2008, the test results of which are given in Table 2.

TABLE 2

As can be seen from Table 2, the sol coatings of examples 1-4 have better aging and yellowing resistance than the sol coatings of comparative examples 1-2, and can better protect the solar cell panel, thereby prolonging the service life of the solar cell panel.

While preferred embodiments of the present invention have been described, additional variations and modifications of these embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the embodiments of the invention.

The technical solutions provided by the present invention are described in detail above, and the principle and the implementation of the present invention are explained in this document by applying specific examples, and the descriptions of the above examples are only used to help understanding the method and the core idea of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present invention.

Claims

1. A preparation method of rare earth metal organic complex coated zinc oxide titanium nano sol is characterized by comprising the following steps:

step three, dispersing the zinc oxide titanium nano particles by ultrasonic, adding a surface modifier, and stirring to perform surface modification on the zinc oxide titanium nano particles;

adding a rare earth metal organic complex into the zinc oxide titanium nano particles with the modified surfaces, continuing to react, and drying to obtain zinc oxide titanium nano sol coated by the rare earth metal organic complex;

in the second step, the catalyst aqueous solution is an acid catalyst aqueous solution obtained by uniformly mixing a catalyst, absolute ethyl alcohol and water; the catalyst is hydrochloric acid;

and dropwise adding the catalyst aqueous solution into the mixed solution to adjust the pH of the mixed solution to 1-3.

2. The method for preparing the rare earth metal organic complex coated zinc titanium oxide nanosol according to claim 1, wherein in the first step, the zinc precursor is zinc acetate or zinc nitrate;

the titanium precursor is titanium tetraisopropoxide or titanium tetrabutoxide;

the reaction solvent is a mixture of absolute ethyl alcohol and isopropanol.

3. The method for preparing the rare earth metal organic complex coated zinc titanium oxide nanosol as claimed in claim 1, wherein in the first step, when the reaction solvent is 100 parts by weight, the sum of the weight of the titanium precursor and the zinc precursor is 20-28 parts; the weight ratio of the zinc precursor to the titanium precursor is 1: 1.3-5.

4. The method for preparing the rare earth metal organic complex coated zinc titanium oxide nanosol according to claim 1, wherein in the second step, the reaction is carried out for 24 hours while stirring, the temperature rise is 80 ℃, and the reaction time is 2 hours.

5. The method for preparing the rare earth metal organic complex coated zinc titanium oxide nanosol according to claim 1, wherein in the third step, the surface modifier is a silane coupling agent or tert-butylamine.

6. The method for preparing the rare earth metal organic complex coated zinc titanium oxide nanosol according to claim 1, wherein in the fourth step, the temperature of the continuous reaction is 80 ℃ and the time is 5 h;

the drying mode is freeze drying;

the rare earth metal organic complex is obtained by reacting rare earth inorganic salt with an organic complex.

7. The method for preparing the rare earth metal organic complex coated zinc titanium oxide nanosol of claim 6, wherein in the fourth step, the rare earth inorganic salt is any two of inorganic salts of ytterbium, europium, cerium and neodymium; the organic complex is a polydentate ligand, a monodentate ligand, acetylacetone or a silane coupling agent;

the weight of the rare earth metal in the rare earth metal organic complex is 0.1-10% of the mass of the zinc oxide titanium nano particles, and the weight of the organic complex is 1-30% of the mass of the zinc oxide titanium nano particles.

8. The method for preparing a rare earth metal organic complex coated zinc titanium oxide nanosol as claimed in claim 1, wherein after the fourth step, the method further comprises the following steps: dispersing the zinc oxide titanium nano sol coated by the rare earth metal organic complex in a spreading solvent;

the spreading solvent is ethylene glycol monomethyl ether or propylene glycol methyl ether acetate.

9. A rare earth metal organic complex coated zinc oxide titanium nano sol, which is characterized by being prepared by the preparation method of the rare earth metal organic complex coated zinc oxide titanium nano sol of any one of claims 1 to 8.