CN106746688B

CN106746688B - Graphene-modification-based lead-free glass powder, preparation method thereof and electronic paste

Info

Publication number: CN106746688B
Application number: CN201710175557.2A
Authority: CN
Inventors: 王惠; 白晋涛; 马倩; 马生华
Original assignee: Northwest University
Current assignee: Northwest University
Priority date: 2017-03-22
Filing date: 2017-03-22
Publication date: 2020-01-10
Anticipated expiration: 2037-03-22
Also published as: CN106746688A

Abstract

The invention provides graphene-modified lead-free glass powder, a preparation method thereof and electronic paste, wherein graphene or modified graphene is modified on the surface of the glass powder through adsorption and bonding, so that the graphene-modified glass powder is prepared, wherein the number of layers of the graphene or the modified graphene is 1-100. The graphene is applied to the modified lead-free glass powder for the first time, the process is simple, the conditions are mild, the prepared glass powder is high in functionalization degree and good in dispersity, when the graphene is applied to the preparation of the electronic paste, the dispersity of silver particles in the electronic paste and the performances of conductivity, paste volatility, leveling property, thixotropy and the like of the silver particles are improved, and the current convergence and derivation effects of the solar cell electrode prepared from the electronic paste are further improved.

Description

Graphene-modification-based lead-free glass powder, preparation method thereof and electronic paste

Technical Field

The invention relates to the technical field of powder materials, in particular to graphene-modified glass powder and a preparation method thereof, and especially relates to graphene-modified high-dispersion lead-free glass powder and a preparation method thereof, as well as electronic paste based on the lead-free glass powder and a preparation method thereof.

Background

With the development of new energy technology, the application and research of solar cells gradually become hot spots in new energy cells. The electronic paste is needed to be used in the preparation of the electrode of the solar cell, and the composition structure of the electronic paste directly influences the current convergence and derivation effects of the prepared cell electrode, so that the electrical performance of the cell electrode is influenced. The graphene material has excellent material characteristics in the aspects of electric conduction, machinery, electricity, optics and the like, has good dispersibility in some solvent matrixes, and particularly has a two-dimensional network structure which is very easy to fill in gaps among glass powder and can form good cohesive force with a silicon substrate, so that the graphene is applied to modify the glass powder to improve the dispersibility of the glass powder, belongs to a brand new application idea of the graphene in preparation of high-dispersion glass powder and high-performance electronic paste, and the prior art does not have a preparation technology of the high-dispersion glass powder based on graphene modification. Meanwhile, solar energy is a clean energy which is concerned, but the conductive paste used by the existing silicon-based solar cell is based on lead paste, and the toxicity of lead is not beneficial to environmental protection, so that the technology for improving the dispersion performance of the existing glass powder, especially the lead-free glass powder, has profound significance for promoting the utilization of the clean energy of the solar energy correspondingly.

Disclosure of Invention

The invention provides graphene modified high-dispersion lead-free glass powder, a preparation method thereof and electronic paste prepared based on the graphene modified high-dispersion lead-free glass powder, which are originally applied to modifying lead-free glass powder, can be widely applied to conductive paste of crystalline silicon solar cells, not only meet the requirement of developing new energy, but also cannot cause pollution to the environment. The invention adopts a condensing agent method for the first time, and uses a condensing agent with specific NH₂The method comprises the steps of modifying graphene oxide by a group substance to obtain modified graphene, mixing and stirring the modified graphene and the lead-free glass powder prepared by a melting quenching method, performing ultrasonic dispersion, cooling, cleaning, filtering and vacuum drying to obtain the graphene-modified high-dispersion lead-free glass powder, and is simple in process, mild in condition, high in functionalization degree and good in dispersibility of the prepared glass powder, and when the glass powder is applied to preparation of electronic paste, the dispersibility of silver particles in the electronic paste and the performances of the silver particles, such as conductivity, paste volatility, leveling property and thixotropy, are improved, and the current convergence and derivation effects of a solar battery electrode prepared by the electronic paste are further improved.

The technical scheme adopted by the invention for solving the technical problems is as follows:

the graphene or modified graphene is modified on the surface of the glass powder through adsorption and bonding, and the number of layers of the graphene or modified graphene is between 1 and 100.

The graphene modification-based glass powder further comprises the following components in percentage by mass: 30 to 55% of Bi₂O₃，10～35％TeO₂，5～15％ZnO，3～5％MgO，5-15％SiO₂，2～4％P₂O₅，5～15％B₂O₃，1～12％Al₂O₃And 0 to 5% of V₂O₅CaO and SnO₂At least one of; modifying graphene on the surface of glass powder in the following way: mixing and reacting glass powder and graphene oxide to obtain graphene oxide modified glass powder, and reducing the graphene oxide modified glass powder into graphene modified glass powder, wherein the mass ratio of the glass powder to the graphene oxide is 2-100: 1; modifying the modified graphene on the surface of the glass powder in the following way: mixing and reacting glass powder and modified graphene oxide to obtain glass powder modified by the modified graphene oxide, and reducing the glass powder modified by the modified graphene oxide into glass powder modified by the modified graphene oxide, wherein the mass ratio of the glass powder to the modified graphene oxide is 2-100: 1.

Further, according to the graphene modification-based glass powder of the present invention, the graphene oxide modification-based glass powder is reduced to graphene modification-based glass powder by using a reducing agent or a hydrogen atmosphere, wherein when reducing is performed by using a reducing agent: the mass ratio of the reducing agent to the graphene oxide modified glass powder is 1-4:1, and the reducing agent is selected from at least one of ascorbic acid, sodium thiosulfate, hydrazine, dimethylhydrazine, hydrazine hydrate, ethylene glycol, diethylene glycol and N, N' -dicyclohexylcarbodiimide, wherein when the reducing is carried out in a hydrogen atmosphere: the flow rate of the hydrogen is controlled to be 10.0-30 ml/min; reducing the glass powder modified by the modified graphene oxide into the glass powder modified by the modified graphene oxide by using a reducing agent or hydrogen atmosphere, wherein when the reducing agent is used for reduction: the mass ratio of the reducing agent to the glass powder modified by the modified graphene oxide is 1-4:1, and the reducing agent is selected from at least one of ascorbic acid, sodium thiosulfate, hydrazine, dimethylhydrazine, hydrazine hydrate, ethylene glycol, diethylene glycol and N, N' -dicyclohexylcarbodiimide, wherein when the reducing is carried out in a hydrogen atmosphere: the flow rate of the hydrogen is controlled to be 10.0-30 ml/min; the graphene or the modified graphene is few-layer graphene with the number of layers being 1-10.

A preparation method of glass powder based on graphene modification comprises the following steps:

the method comprises the following steps: preparing glass powder;

step two: preparing an organic graphene oxide dispersion solution;

step three: uniformly dispersing the glass powder prepared in the step one in the graphene oxide organic dispersion solution prepared in the step two for full reaction, and then filtering, washing and drying to prepare graphene oxide modified glass powder;

step four: and D, reducing the graphene oxide modified glass powder obtained in the step three to obtain the graphene modified glass powder.

Further, according to the preparation method of the graphene modification-based glass powder, in the third step, the mass ratio of the glass powder to the graphene oxide dispersed in the graphene oxide organic dispersion solution is 2-100: 1; in the fourth step, reducing the glass powder modified by the graphene oxide into the glass powder modified by the graphene oxide by using a reducing agent or hydrogen atmosphere, wherein when the reducing agent is used for reduction: the mass ratio of the reducing agent to the graphene oxide modified glass powder is 1-4:1, and the reducing agent is selected from at least one of ascorbic acid, sodium thiosulfate, hydrazine, dimethylhydrazine, hydrazine hydrate, ethylene glycol, diethylene glycol and N, N' -dicyclohexylcarbodiimide, wherein when the reducing is carried out in a hydrogen atmosphere: the flow rate of the hydrogen is controlled at 10.0-30 ml/min.

the method comprises the following steps: preparing glass powder;

step two: preparing an organic graphene oxide dispersion solution;

step three: modifying the graphene oxide organic dispersion solution prepared in the second step to obtain a modified graphene oxide dispersion solution;

step four: uniformly dispersing the glass powder prepared in the first step into the modified graphene oxide dispersion liquid prepared in the third step for full reaction, and then filtering, washing and drying to prepare the modified graphene oxide modified glass powder;

step five: and D, reducing the modified graphene oxide modified glass powder prepared in the step four to obtain the modified graphene oxide modified glass powder.

Further, according to the preparation method of the graphene modification-based glass powder, the third step specifically comprises: (1) uniformly dispersing a modifier into the graphene oxide organic dispersion solution prepared in the second step to obtain a modified graphene oxide reaction solution, wherein the mass ratio of the modifier to the graphene oxide dispersed in the graphene oxide organic dispersion solution is 2-15:1, and the modifier is selected from at least one of 3- (aminopropyl) triethoxysilane, 3- (trimethoxysilyl) -1-propylamine, 3-aminopropyl methyldiethoxysilane, diethylenetriaminopropyl trimethoxysilane, tert-butyl propylamino trimethoxysilane and 4-amino-3, 3-dimethylbutyl trimethoxysilane; (2) and filtering, washing and drying the modified graphene oxide reaction solution to obtain modified graphene oxide dry powder, and uniformly dispersing the modified graphene oxide dry powder in an organic solvent to obtain a modified graphene oxide dispersion solution.

Further, according to the preparation method of the graphene modification-based glass powder, in the fourth step, the mass ratio of the glass powder to the modified graphene oxide dry powder dispersed in the modified graphene oxide dispersion liquid is 2-100: 1; in the fifth step, reducing the glass powder modified by the modified graphene oxide into the glass powder modified by the modified graphene oxide by using a reducing agent or hydrogen atmosphere, wherein when the reducing agent is used for reduction: the mass ratio of the reducing agent to the glass powder modified by the modified graphene oxide is 1-4:1, and the reducing agent is selected from at least one of ascorbic acid, sodium thiosulfate, hydrazine, dimethylhydrazine, hydrazine hydrate, ethylene glycol, diethylene glycol and N, N' -dicyclohexylcarbodiimide, wherein when the reducing is carried out in a hydrogen atmosphere: the flow rate of the hydrogen is controlled at 10.0-30 ml/min.

Further, according to the preparation method of the graphene modification-based glass powder, the glass powder is prepared in the following manner in the first step: (1) is prepared from the following components in percentage by massTaking the following components: 30 to 55% of Bi₂O₃，10～35％TeO₂，5～15％ZnO，3～5％MgO，5-15％SiO₂，2～4％P₂O₅，5～15％B₂O₃，1～12％Al₂O₃And 0 to 5% of V₂O₅CaO and SnO₂At least one of; (2) uniformly mixing the weighed components, smelting in a high-temperature electric furnace, taking out, quenching in distilled water to room temperature to obtain coarse glass powder, and further crushing the coarse glass powder into glass powder with the required particle size; preparing the graphene oxide organic dispersion solution in the following manner: (1) oxidizing graphite to prepare graphene oxide; (2) uniformly dispersing graphene oxide in an organic solvent to prepare a graphene oxide organic dispersion solution, wherein the weight percentage concentration of the graphene oxide in the solution is 0.05-5.0 wt%, and the organic solvent is selected from at least one of alcohol ester dodeca, terpineol, tributyl citrate, triethanolamine, butyl carbitol, dimethyl glutarate, dimethyl adipate, dimethyl phthalate and oleic acid.

The electronic paste is characterized by comprising the following components in percentage by mass: 3-5% of glass powder, 80-85% of silver powder and 10-15% of organic carrier, wherein the glass powder is the glass powder based on graphene modification, or the glass powder based on graphene modification, which is prepared according to the preparation method provided by the invention.

The technical scheme of the invention at least has the following technical innovation and technical effect:

(1) the invention initiatively applies the graphene to modify the lead-free glass powder by adopting a condensing agent method and using the graphene with specific NH₂Modifying graphene oxide by a substance of a group to obtain modified graphene oxide, mixing the modified graphene oxide with lead-free glass powder prepared by a melt quenching method to obtain modified graphene oxide modified high-dispersion lead-free glass powder, and reducing to obtain graphene modified high-dispersion lead-free glass powderThe lead-free glass powder for the dispersive electronic paste.

(2) According to the invention, graphene oxide can be directly mixed with the lead-free glass powder prepared by a melt quenching method to prepare graphene oxide modified high-dispersion lead-free glass powder, and then the graphene oxide modified high-dispersion lead-free glass powder is obtained by reduction. The lead-free glass powder with lower requirement on dispersibility can be modified by graphene based on the method, so that the cost can be reduced and the process can be simplified, and the lead-free glass powder with higher requirement on dispersibility can be considered to be further modified by graphene oxide.

(3) When the graphene modified lead-free glass powder prepared by the invention is applied to the preparation of electronic paste, the paste volatility, the environmental protection property, the leveling property, the thixotropy, the silver particle dispersibility and the electric conductivity of the electronic paste are improved, the current convergence and derivation effects of a solar battery electrode prepared by the electronic paste are further improved, the utilization of a solar battery and the development of new energy are promoted, and the environment is not polluted, so that a new application idea of graphene in the preparation of the solar battery paste is provided, and the graphene modified lead-free glass powder has a wide market popularization prospect.

Detailed Description

The technical solutions of the present invention are described in detail below to enable those skilled in the art to more clearly understand the present invention, but the present invention is not limited thereto.

The invention innovatively provides graphene-modified glass powder and a preparation method thereof, and particularly relates to graphene-modified high-dispersion lead-free glass powder and a preparation method thereof, and electronic paste based on the lead-free glass powder and a preparation method thereof.

Firstly, the preparation method of the graphene-modified high-dispersion lead-free glass powder provided by the invention comprises the following steps:

step one, preparing lead-free glass powder:

(1) firstly, accurately weighing each oxide by using an analytical balance, wherein the components and the weight percentage content are as follows: 30 to 55% of Bi₂O₃，10～35％TeO₂，5～15％ZnO，3～5％MgO，5-15％SiO₂，2～4％P₂O₅，5～15％B₂O₃，1～12％Al₂O₃Further preferably comprises 0 to 5 weight percent of oxide V₂O₅、CaO、SnO₂The total content of the percentage of each oxide is 100 percent;

(2) preparing required glass powder by adopting melt quenching, uniformly mixing the weighed oxides, putting the mixture into an aluminum crucible, putting the aluminum crucible into a high-temperature electric furnace with a set temperature (about 1200 ℃) to smelt for 10-50min, taking out the aluminum crucible, quenching the aluminum crucible in distilled water to room temperature to obtain crude glass powder, further crushing the obtained crude glass powder, preferably crushing the crude glass powder to 3-5 mu m by using a jet mill, washing and drying to obtain the lead-free glass powder sample for later use.

Step two, preparing a modified graphene oxide dispersion liquid:

(1) and preparing graphene oxide. The graphene oxide is an oxide of graphite, after the graphite is oxidized, the oxygen-containing functional groups on the graphite are increased, so that the graphite is more active than the graphite in property, and the property of the graphite can be improved through various reactions with the oxygen-containing functional groups. It is further preferred (optional) that the graphene oxide has the following structure:

(2) preparing the graphene oxide organic dispersion solution. Uniformly dispersing the graphene oxide prepared in the step (1) in an organic solvent to obtain a graphene oxide organic dispersion solution, wherein the weight percentage concentration of the graphene oxide in the organic dispersion solution is 0.05-5.0 wt%, preferably 0.1-2 wt%, more preferably 0.1-1.2 wt%, further 0.1-0.8 wt%, and further 0.4-0.5 wt%, and the organic solvent is at least one selected from the group consisting of alcohol ester twelve, terpineol, tributyl citrate, triethanolamine, butyl carbitol, dimethyl glutarate, dimethyl adipate, dimethyl phthalate and oleic acid. More preferably, the organic solvent is a mixture of two solvents selected from alcohol ester twelve, terpineol, tributyl citrate, triethanolamine, butyl carbitol, dimethyl glutarate, dimethyl adipate, dimethyl phthalate and oleic acid, and the mixing mass ratio of the two solvents is 1: 1-2. More preferably, the organic solvent is prepared by mixing the following components according to the following configuration: the alcohol ester is composed of 30-42 parts by weight of alcohol ester dodeca, 3-7 parts by weight of terpineol, 2-5 parts by weight of tributyl citrate, 6-9 parts by weight of triethanolamine, 1-1.8 parts by weight of butyl carbitol, 2-5 parts by weight of dimethyl glutarate, 1-2 parts by weight of dimethyl adipate, 4-6 parts by weight of dimethyl phthalate and 9-18 parts by weight of oleic acid. The specific method is preferably as follows: adding graphene oxide into the organic solvent at room temperature (25 ℃), then oscillating and mixing the organic solvent added with the graphene oxide on a vortex mixer for 20-30min, and then ultrasonically dispersing the organic solvent with a probe type ultrasonic disperser under the power of 750W for 3-5 hours to uniformly disperse the graphene oxide in the organic solvent to prepare the graphene oxide organic dispersion solution.

(3) And preparing a modified graphene oxide dispersion liquid. Uniformly dispersing a modifier in the graphene oxide organic dispersion solution prepared in the step (2), wherein the mass ratio of the modifier to the graphene oxide dispersed in the graphene oxide organic dispersion solution prepared in the step (2) is 2-15:1, preferably 3-10:1, further preferably 5-10:1, and further preferably 6-8: 1. The modifier is selected from one or at least one of 3- (aminopropyl) triethoxysilane, 3- (trimethoxysilyl) -1-propylamine, 3-aminopropylmethyldiethoxysilane, diethylenetriaminopropyltrimethoxysilane, tert-butylaminotrimethoxysilane and 4-amino-3, 3-dimethylbutyltrimethoxysilane, and can be prepared by mixing the following components preferably: 8 to 12 parts by weight of 3- (aminopropyl) triethoxysilane, 1 to 2 parts by weight of 3- (trimethoxysilyl) -1-propylamine, 2 to 5 parts by weight of 3-aminopropylmethyldiethoxysilane, 0.5 to 1.2 parts by weight of diethylenetriaminopropyltrimethoxysilane, 0.3 to 0.8 part by weight of t-butylpropylaminotrimethoxysilane and 0.3 to 0.6 part by weight of 4-amino-3, 3-dimethylbutyltrimethoxysilane. And performing silanization modification on the surface of graphene oxide in the solution by using the modifier to obtain silanization modified graphene oxide dispersion liquid. The specific method is preferably as follows: adding the modifier into the graphene organic dispersion solution at room temperature (25 ℃), heating to 40-70 ℃, preferably 60 ℃, dispersing in 70W ultrasonic waves for 0.5-4 h, and modifying the surface of graphene oxide by using the modifier to obtain a modified graphene oxide dispersion solution.

(4) Purifying the modified graphene oxide dispersion liquid. Firstly, filtering the modified graphene oxide dispersion liquid prepared in the step (3) through a PVDF membrane with the pore diameter of 0.4-0.6 mu m (preferably 0.45 mu m), washing the modified graphene oxide dispersion liquid for multiple times by using ethanol or acetone to remove residual modifier, and finally drying the modified graphene oxide dispersion liquid in a vacuum drying oven for 24 hours to obtain modified graphene oxide dry powder. And then, uniformly dispersing the prepared modified graphene oxide dry powder in an organic solvent again to obtain a purified modified graphene oxide dispersion liquid. Wherein the weight percentage concentration of the modified graphene oxide in the organic dispersion solution is 1-10.0 wt%, preferably 1-5 wt%, more preferably 1.2-4.5 wt%, and further 1.5-2.8 wt%, and the organic solvent is at least one selected from alcohol ester twelve, terpineol, tributyl citrate, triethanolamine, butyl carbitol, dimethyl glutarate, dimethyl adipate, dimethyl phthalate, and oleic acid. More preferably, the organic solvent is a mixture of two solvents selected from alcohol ester twelve, terpineol, tributyl citrate, triethanolamine, butyl carbitol, dimethyl glutarate, dimethyl adipate, dimethyl phthalate and oleic acid, the mixing mass ratio of the two solvents is 1:1-2, and more preferably, the organic solvent is prepared by mixing the following components in the following configuration: the alcohol ester is composed of 20-30 parts by weight of alcohol ester dodeca, 3-5 parts by weight of terpineol, 2-6 parts by weight of tributyl citrate, 2-4 parts by weight of triethanolamine, 1-1.5 parts by weight of butyl carbitol, 3-6 parts by weight of dimethyl glutarate, 1.2-2 parts by weight of dimethyl adipate, 2-4 parts by weight of dimethyl phthalate and 7-12 parts by weight of oleic acid. Wherein the number of graphene layers in the modified graphene oxide is between 1 and 100 layers, preferably between 1 and 60 layers, further preferably between 1 and 30 layers, more preferably between 1 and 10 layers, and most preferably between 1 and 5 layers.

Step three: the preparation method of the graphene-modified lead-free glass powder can be implemented by one of the following two ways:

the method comprises the following steps:

(1) fully mixing the lead-free glass powder prepared in the first step with the graphene oxide organic dispersion solution prepared in the second step (2), adding the lead-free glass powder into the graphene oxide organic dispersion solution, mixing and stirring for 20-30min, performing ultrasonic dispersion for 2-3h, further stirring and mixing for 1-12h to obtain a uniform dispersion solution of the lead-free glass powder and the graphene oxide, modifying the graphene oxide on the surface of the lead-free glass powder through electrostatic adsorption and hydrogen bonding, filtering the dispersion solution with a PVDF (polyvinylidene fluoride) membrane, washing with ethanol or acetone for multiple times to remove residual organic solvent, and finally drying in a vacuum drying oven for 24h to obtain the graphene oxide modified lead-free glass powder. Wherein the mass ratio of the lead-free glass powder to the graphene oxide dispersed in the graphene oxide organic dispersion solution is 2-100:1, preferably 10-100:1, further preferably 20-80:1, and more preferably 50-60: 1.

(2) And (2) carrying out reduction treatment on the graphene oxide modified lead-free glass powder prepared in the step (1), and reducing the graphene oxide modified lead-free glass powder by adopting a reducing agent to obtain the high-dispersity graphene modified lead-free glass powder. Specifically, a reducing agent and the graphene oxide modified lead-free glass powder are weighed according to a mass ratio of 1-4:1, preferably 1-3:1, and further preferably 2-3:1, then the reducing agent and the graphene oxide modified lead-free glass powder are uniformly mixed to react, preferably the graphene oxide modified lead-free glass powder is dispersed in the reducing agent to obtain a reduction dispersion solution, then the reduction dispersion solution is continuously stirred for 12-24 hours at 50-70 ℃ (preferably 60 ℃) on a magnetic stirrer, after full reaction, the graphene oxide in the graphene oxide modified lead-free glass powder is reduced to graphene, finally the reduction dispersion solution is filtered through a PVDF membrane with a pore diameter of 0.4-0.6 μm (preferably 0.45 μm), and residual reducing agent solvent is removed by washing with ethanol or acetone for multiple times, and drying the glass powder in a vacuum drying oven for 24 hours to obtain the graphene modified lead-free glass powder. Wherein the reducing agent is at least one selected from ascorbic acid, sodium thiosulfate, hydrazine, dimethylhydrazine, hydrazine hydrate, ethylene glycol, diethylene glycol and N, N' -dicyclohexylcarbodiimide or a mixture of two of the two (mixing ratio is 1-2:1), and more preferably the reducing agent is selected from hydrazine hydrate or ethylene glycol.

In addition, the step (2) can also be reduced based on a hydrogen atmosphere: placing the graphene oxide modified lead-free glass powder prepared in the step (1) in a hydrogen atmosphere for a predetermined period of time, and controlling hydrogen H₂The flow rate of (A) is 10.0 to 30ml/min, and further preferably H₂The flow rate of (2) is controlled to be 20ml/min, so that the graphene oxide modified lead-free glass powder is reduced into the highly dispersed graphene modified lead-free glass powder.

The second mode comprises the following steps:

(1) fully mixing the lead-free glass powder prepared in the first step with the modified graphene oxide dispersion liquid prepared in the second step, specifically, adding the lead-free glass powder into the modified graphene oxide dispersion liquid, mixing and stirring for 20-30min, performing ultrasonic dispersion for 2-3h, further stirring and mixing for 1-12h to obtain a mixed dispersion liquid of the lead-free glass powder and the modified graphene oxide, modifying the modified graphene oxide on the surface of the lead-free glass powder through electrostatic adsorption and hydrogen bond action, finally filtering the mixed dispersion liquid by using a PVDF (polyvinylidene fluoride) membrane, washing the mixed dispersion liquid for multiple times by using ethanol or acetone to remove residual organic solvent, and finally drying the mixed dispersion liquid in a vacuum drying box for 24h to obtain the lead-free glass powder modified by the modified graphene oxide. Wherein the mass ratio of the lead-free glass powder to the modified graphene oxide is 2-100:1, preferably 10-100:1, further preferably 20-80:1, and more preferably 50-60: 1.

(2) And (2) carrying out reduction treatment on the lead-free glass powder modified by the modified graphene oxide prepared in the step (1), and reducing the modified graphene oxide in the lead-free glass powder modified by the modified graphene oxide by adopting a reducing agent to obtain the high-dispersity modified graphene-modified lead-free glass powder. Specifically, a reducing agent and the modified graphene oxide modified lead-free glass powder are weighed according to a mass ratio of 1-4:1, preferably 1-3:1, and further preferably 2-3:1, then the reducing agent and the modified graphene oxide modified lead-free glass powder are uniformly mixed to react, preferably, the modified graphene oxide modified lead-free glass powder is dispersed in the reducing agent to obtain a reduction dispersion solution, then, the reduction dispersion solution is continuously stirred for 12-24 hours at 50-70 ℃ (preferably 60 ℃) on a magnetic stirrer, after full reaction, the modified graphene oxide in the modified graphene oxide modified lead-free glass powder is reduced to modified graphene, finally, the reduction dispersion solution is filtered through a PVDF membrane with a pore diameter of 0.4-0.6 μm (preferably 0.45 μm), and residual reducing agent solvent is removed by washing with ethanol or acetone for multiple times, and drying the glass powder in a vacuum drying oven for 24 hours to obtain the modified graphene modified lead-free glass powder. Wherein the reducing agent is at least one selected from ascorbic acid, sodium thiosulfate, hydrazine, dimethylhydrazine, hydrazine hydrate, ethylene glycol, diethylene glycol and N, N' -dicyclohexylcarbodiimide or a mixture of two of the two (mixing ratio is 1-2:1), and more preferably the reducing agent is selected from hydrazine hydrate or ethylene glycol.

In addition, the step (2) can also be reduced based on a hydrogen atmosphere: placing the modified graphene oxide modified lead-free glass powder prepared in the step (1) in a hydrogen atmosphere for a predetermined period of time, and controlling hydrogen H₂The flow rate of (A) is 10.0 to 30ml/min, and further preferably H₂The flow rate of (2) is controlled to be 20ml/min, so that the modified graphene oxide modified lead-free glass powder is reduced to highly dispersed modified graphene modified lead-free glass powder.

It should be particularly noted that the graphene-modified lead-free glass powder provided by the present invention refers to a lead-free glass powder having a surface containing graphene, where the graphene may exist in a simple graphene form or in a functional graphene form, such as modified graphene, that is, the graphene-modified lead-free glass powder covers both graphene-modified lead-free glass powder and modified graphene-modified lead-free glass powder. The graphene is thick-layer graphene with the number of layers being 1-100, preferably multi-layer graphene with the number of layers being 1-30, more preferably few-layer graphene with the number of layers being 1-10, and even more preferably double-layer graphene or single-layer graphene, and at least 95% of the graphene meets the layer number requirement.

The invention further provides a preparation method of the electronic paste for the solar cell, which comprises the following steps:

weighing the following components in percentage by mass: 3-5% of graphene-modified lead-free glass powder, 80-85% of silver powder and 10-15% of organic carrier; wherein the silver powder is spherical, the particle diameter of the silver powder is 1-4 μm, and the tap density is 3-6g/cm³The preferred structural parameters are: the particle diameter D50 is 1.0 μm, the D90 is 3.2 μm, and the tap density is 5-6g/cm³. The organic carrier is selected from at least one of alcohol ester dodeca, terpineol, tributyl citrate and butyl carbitol acetate, and preferably, the organic carrier is prepared from two of the alcohol ester dodeca, the terpineol, the tributyl citrate and the butyl carbitol acetate according to a mass ratio of 1-2:1, and more preferably the organic vehicle is a mixture of 5-12 parts by weight of alcohol ester dodeca, 2-4 parts by weight of terpineol, 0.8-1.2 parts by weight of tributyl citrate, and 0.5-1.5 parts by weight of butyl carbitol acetate.

And (II) mixing the graphene-modified lead-free glass powder, the silver powder and the organic carrier, and then putting the mixture on a three-roll machine for fully and uniformly mixing to obtain the electronic paste for the solar cell, wherein the fineness of the paste is less than 10 mu m, the viscosity is 110-220 Pa.s, and the thixotropic index is 3.4-5.9. The graphene-modified lead-free glass powder is graphene-modified lead-free glass powder or modified graphene-modified lead-free glass powder or a mixture of the graphene-modified lead-free glass powder and the modified graphene-modified lead-free glass powder (preferably in a mass ratio of 1-2: 1).

Examples

Specific examples of preparing the graphene-modified lead-free glass powder and the solar cell electronic paste of the invention are given below.

Example 1

A preparation method of lead-free glass powder comprises the following steps:

weighing the following substances in percentage by weight: 30% Bi₂O₃，35％TeO₂，15％ZnO，3％MgO，5％SiO₂，2％P₂O₅，5％B₂O₃，5％Al₂O₃And then uniformly mixing the weighed oxides, putting the mixed oxides into an aluminum crucible, putting the aluminum crucible into a high-temperature electric furnace at about 1200 ℃ for smelting for 10min, taking out the aluminum crucible, quenching the aluminum crucible in distilled water to room temperature to obtain coarse glass powder, then crushing the coarse glass powder to 3-5 mu m by using a jet mill, washing and drying to obtain the lead-free glass powder sample.

Example 2

A preparation method of lead-free glass powder comprises the following steps:

weighing the following substances in percentage by weight: 55% Bi₂O₃，10％TeO₂，5％ZnO，3％MgO，5％SiO₂，2％P₂O₅，10％B₂O₃，10％Al₂O₃And then, uniformly mixing the weighed oxides, putting the mixed oxides into an aluminum crucible, putting the aluminum crucible into a high-temperature electric furnace at about 1200 ℃ to be smelted for 50min, taking out the smelted crucible, quenching the smelted crucible to room temperature in distilled water to obtain coarse glass powder, then crushing the coarse glass powder to 3-5 mu m in particle size by using a jet mill, washing and drying to obtain the lead-free glass powder sample.

Example 3

A preparation method of lead-free glass powder comprises the following steps:

weighing the following substances in percentage by weight: 40% Bi₂O₃，20％TeO₂，10％ZnO，4％MgO，6％SiO₂，3％P₂O₅，9％B₂O₃，8％Al₂O₃Then, the weighed oxides are evenly mixed and placed in an aluminum crucible, then the aluminum crucible is placed in a high-temperature electric furnace with the temperature of about 1200 ℃ to be smelted for 50min, then the smelted aluminum crucible is taken out and quenched in distilled water to room temperature to obtain crude glass powder, and then the crude glass powder is obtainedAnd (3) crushing the particle size of the coarse glass powder to 3-5 microns by using a jet mill, and washing and drying to obtain the lead-free glass powder sample.

Example 4

A preparation method of lead-free glass powder comprises the following steps:

weighing the following substances in percentage by weight: 35% of Bi₂O₃，18％TeO₂，12％ZnO，5％MgO，5％SiO₂，3％P₂O₅，12％B₂O₃，6％Al₂O₃，1％V₂O₅，2.5％CaO，0.5％SnO₂And then uniformly mixing the weighed oxides, putting the mixed oxides into an aluminum crucible, putting the aluminum crucible into a high-temperature electric furnace at about 1200 ℃ for smelting for 40min, taking out the aluminum crucible, quenching the aluminum crucible in distilled water to room temperature to obtain coarse glass powder, then crushing the coarse glass powder to 3-5 mu m in particle size by using a jet mill, washing and drying to obtain the lead-free glass powder sample.

Example 5

A preparation method of a graphene oxide dispersion liquid comprises the following steps: adding graphene oxide into an organic solvent at room temperature (25 ℃), then mixing for more than 20min in a vortex mixer in an oscillating way, and then carrying out ultrasonic dispersion for 3 hours under the power of 750W by using a probe type ultrasonic dispersion instrument so that the graphene oxide is uniformly dispersed in the organic solvent to prepare a graphene oxide organic dispersion solution, wherein the weight percentage concentration of the graphene oxide in the organic dispersion solution is 0.1 wt%, and the organic solvent is selected from at least one of alcohol ester dodeca, terpineol, tributyl citrate, triethanolamine, butyl carbitol, dimethyl glutarate, dimethyl adipate, dimethyl phthalate and oleic acid.

Example 6

A preparation method of a graphene oxide dispersion liquid comprises the following steps: adding graphene oxide into an organic solvent at room temperature (25 ℃), mixing for more than 20min in a vortex mixer in an oscillating way, and then carrying out ultrasonic dispersion for more than 3 hours under the power of 750W by using a probe type ultrasonic dispersion instrument so that the graphene oxide is uniformly dispersed in the organic solvent to prepare a graphene oxide organic dispersion solution, wherein the weight percentage concentration of the graphene oxide in the organic dispersion solution is 2 wt%, and the organic solvent is selected from at least one of alcohol ester dodeca, terpineol, tributyl citrate, triethanolamine, butyl carbitol, dimethyl glutarate, dimethyl adipate, dimethyl phthalate and oleic acid.

Example 7

A preparation method of a graphene oxide dispersion liquid comprises the following steps: adding graphene oxide into an organic solvent at room temperature (25 ℃), then mixing for more than 20min in a vortex mixer in an oscillating way, and then carrying out ultrasonic dispersion for more than 3 hours under the power of 750W by using a probe type ultrasonic dispersion instrument so that the graphene oxide is uniformly dispersed in the organic solvent to prepare a graphene oxide organic dispersion solution, wherein the weight percentage concentration of the graphene oxide in the organic dispersion solution is 1.2 wt%, and the organic solvent is selected from at least one of alcohol ester twelve, terpineol, tributyl citrate, triethanolamine, butyl carbitol, dimethyl glutarate, dimethyl adipate, dimethyl phthalate and oleic acid.

Example 8

A preparation method of a graphene oxide dispersion liquid comprises the following steps: adding graphene oxide into an organic solvent at room temperature (25 ℃), then mixing for more than 20min in a vortex mixer in an oscillating way, and then carrying out ultrasonic dispersion for more than 3 hours under the power of 750W by using a probe type ultrasonic disperser to uniformly disperse the graphene oxide in the organic solvent to prepare a graphene oxide organic dispersion solution, wherein the weight percentage concentration of the graphene oxide in the organic dispersion solution is 0.5 wt%, and the organic solvent is prepared by mixing the following components: consists of 30 weight portions of alcohol ester twelve, 3 weight portions of terpineol, 2 weight portions of tributyl citrate, 6 weight portions of triethanolamine, 1 weight portion of butyl carbitol, 2 weight portions of dimethyl glutarate, 1 weight portion of dimethyl adipate, 4 weight portions of dimethyl phthalate and 9 weight portions of oleic acid.

Example 9

A preparation method of a modified graphene oxide dispersion liquid comprises the steps of adding a modifier into the graphene oxide dispersion liquid prepared in any one of examples 5-8 at room temperature (25 ℃), heating to 40 ℃, dispersing in 70W ultrasonic waves for 0.5h, modifying the surface of graphene oxide by using the modifier, wherein the mass ratio of the modifier to graphene oxide is 2:1, the modifier is selected from 3- (aminopropyl) triethoxysilane, obtaining the modified graphene oxide dispersion liquid, filtering the modified graphene oxide dispersion liquid through a PVDF membrane with the pore diameter of 0.5 mu m, washing the PVDF membrane with ethanol for multiple times to remove residual modifier, and drying in a vacuum drying oven for 24h to obtain modified graphene oxide dry powder. And then, uniformly dispersing the modified graphene oxide dry powder in an organic solvent again, and controlling the weight percentage concentration of the modified graphene oxide in the organic dispersion solution to be 1 wt% to obtain a purified modified graphene oxide dispersion solution, wherein the organic solvent is the same as the above.

Example 10

A preparation method of a modified graphene oxide dispersion liquid comprises the steps of adding a modifier into the graphene oxide dispersion liquid prepared in any one of examples 5-8 at room temperature (25 ℃), heating to 70 ℃, dispersing in 70W ultrasonic waves for 4 hours, modifying the surface of graphene oxide by using the modifier, wherein the mass ratio of the modifier to graphene oxide is 15:1, the modifier is selected from 3- (trimethoxysilyl) -1-propylamine, obtaining the modified graphene oxide dispersion liquid, filtering the modified graphene oxide dispersion liquid through a PVDF membrane with the pore diameter of 0.5 mu m, washing the modified graphene oxide dispersion liquid with ethanol for multiple times to remove residual modifier, and drying in a vacuum drying oven for 24 hours to obtain modified graphene oxide dry powder. And then, uniformly dispersing the modified graphene oxide dry powder in an organic solvent again, and controlling the weight percentage concentration of the modified graphene oxide in the organic dispersion solution to be 5 wt% to obtain a purified modified graphene oxide dispersion solution, wherein the organic solvent is the same as the above.

Example 11

A preparation method of a modified graphene oxide dispersion liquid comprises the steps of adding a modifier into the graphene oxide dispersion liquid prepared in any one of examples 5-8 at room temperature (25 ℃), heating to 60 ℃, dispersing in 70W ultrasonic waves for 3 hours, and modifying the surface of graphene oxide by using the modifier, wherein the mass ratio of the modifier to graphene oxide is 10:1, and the modifier is selected from 3-aminopropylmethyldiethoxysilane to obtain the modified graphene oxide dispersion liquid. And filtering the modified graphene oxide dispersion liquid through a PVDF membrane with the aperture of 0.5 mu m, washing the modified graphene oxide dispersion liquid for multiple times by using ethanol to remove residual modifier, and finally drying the modified graphene oxide dispersion liquid in a vacuum drying oven for 24 hours to obtain modified graphene oxide dry powder. And then, uniformly dispersing the modified graphene oxide dry powder in the organic solvent again, and controlling the weight percentage concentration of the modified graphene oxide in the organic dispersion solution to be 2.8 wt% to obtain a purified modified graphene oxide dispersion solution, wherein the organic solvent is the same as the above.

Example 12

A preparation method of a modified graphene oxide dispersion liquid comprises the steps of adding a modifier into the graphene oxide dispersion liquid prepared in any one of examples 5-8 at room temperature (25 ℃), heating to 60 ℃, dispersing in 70W ultrasonic waves for 3 hours, modifying the surface of graphene oxide by using the modifier, wherein the mass ratio of the modifier to graphene oxide is 8:1, the modifier is selected from 4-amino-3, 3-dimethylbutyl trimethoxy silane, obtaining the modified graphene oxide dispersion liquid, filtering the modified graphene oxide dispersion liquid through a PVDF membrane with the pore diameter of 0.5 mu m, washing the modified graphene oxide dispersion liquid with ethanol for multiple times to remove residual modifier, and drying in a vacuum drying oven for 24 hours to obtain modified graphene oxide dry powder. And then, uniformly dispersing the modified graphene oxide dry powder in the organic solvent again, and controlling the weight percentage concentration of the modified graphene oxide in the organic dispersion solution to be 1.5 wt% to obtain a purified modified graphene oxide dispersion solution, wherein the organic solvent is the same as the above.

Example 13

A preparation method of graphene modification-based lead-free glass powder comprises the following steps: fully mixing the lead-free glass powder prepared in any one of the embodiments 1 to 4 with the graphene oxide dispersion liquid prepared in any one of the embodiments 5 to 8, wherein the mass ratio of the lead-free glass powder to the graphene oxide is controlled to be 2:1, mixing and stirring for 30min, performing ultrasonic dispersion for 3h, further stirring and mixing for 12h to obtain a uniform dispersion liquid of the lead-free glass powder and the graphene oxide, finally filtering the dispersion liquid by using a PVDF (polyvinylidene fluoride) membrane, washing with acetone for multiple times to remove residual organic solvent, and finally drying in a vacuum drying oven for 24h to obtain the lead-free glass powder modified by the graphene oxide. Then weighing a reducing agent and the graphene oxide modified lead-free glass powder according to the mass ratio of 4:1, dispersing the graphene oxide modified lead-free glass powder in the reducing agent for reaction to obtain a reduction dispersion liquid, then continuously stirring the reduction dispersion liquid for 24 hours at 70 ℃ on a magnetic stirrer, reducing the graphene oxide in the graphene oxide modified lead-free glass powder into graphene after full reaction, finally filtering the reduction dispersion liquid through a PVDF membrane with the aperture of 0.5 mu m, washing with ethanol for multiple times to remove residual reducing agent solvent, drying in a vacuum drying oven for 24h to obtain the graphene-modified lead-free glass powder, wherein the reducing agent is any one selected from ascorbic acid, sodium thiosulfate, hydrazine, dimethylhydrazine, hydrazine hydrate, ethylene glycol, diethylene glycol and N, N' -dicyclohexylcarbodiimide.

Example 14

A preparation method of graphene modification-based lead-free glass powder comprises the following steps: fully mixing the lead-free glass powder prepared in any one of the embodiments 1 to 4 with the graphene oxide dispersion liquid prepared in any one of the embodiments 5 to 8, wherein the mass ratio of the lead-free glass powder to the graphene oxide is controlled to be 100:1, mixing and stirring for 20min, performing ultrasonic dispersion for 2h, further stirring and mixing for 1h to obtain a uniform dispersion liquid of the lead-free glass powder and the graphene oxide, filtering the dispersion liquid by using a PVDF (polyvinylidene fluoride) membrane, washing with acetone for multiple times to remove residual organic solvent, and finally drying in a vacuum drying oven for 24h to obtain the graphene oxide modified lead-free glass powder. Then weighing a reducing agent and the graphene oxide modified lead-free glass powder according to the mass ratio of 1:1, dispersing the graphene oxide modified lead-free glass powder in the reducing agent for reaction to obtain a reduction dispersion liquid, then continuously stirring the reduction dispersion liquid for 24 hours at 70 ℃ on a magnetic stirrer, reducing the graphene oxide in the graphene oxide modified lead-free glass powder into graphene after full reaction, finally filtering the reduction dispersion liquid through a PVDF membrane with the aperture of 0.5 mu m, washing with ethanol for multiple times to remove residual reducing agent solvent, drying in a vacuum drying oven for 24h to obtain the graphene-modified lead-free glass powder, wherein the reducing agent is selected from the mixture of two of ascorbic acid, sodium thiosulfate, hydrazine, dimethylhydrazine, hydrazine hydrate, ethylene glycol, diethylene glycol and N, N' -dicyclohexylcarbodiimide.

Example 15

A preparation method of graphene modification-based lead-free glass powder comprises the following steps: fully mixing the lead-free glass powder prepared in any one of the embodiments 1 to 4 with the graphene oxide dispersion liquid prepared in any one of the embodiments 5 to 8, wherein the mass ratio of the lead-free glass powder to the graphene oxide is controlled to be 50:1, mixing and stirring for 30min, performing ultrasonic dispersion for 2h, further stirring and mixing for 8h to obtain a uniform dispersion liquid of the lead-free glass powder and the graphene oxide, filtering the dispersion liquid by using a PVDF (polyvinylidene fluoride) membrane, washing with acetone for multiple times to remove residual organic solvent, and finally drying in a vacuum drying oven for 24h to obtain the lead-free glass powder modified by the graphene oxide. Then weighing a reducing agent and the lead-free glass powder modified by the graphene oxide according to a mass ratio of 2:1, dispersing the lead-free glass powder modified by the graphene oxide in the reducing agent for reaction to obtain a reduction dispersion liquid, then continuously stirring the reduction dispersion liquid on a magnetic stirrer at 70 ℃ for 20 hours, reducing the graphene oxide in the lead-free glass powder modified by the graphene oxide into graphene after full reaction, finally filtering the reduction dispersion liquid through a PVDF membrane with a pore size of 0.5 mu m, washing with ethanol for multiple times to remove residual reducing agent solvent, and drying in a vacuum drying oven for 24 hours to obtain the lead-free glass powder modified by the graphene, wherein the reducing agent is selected from hydrazine hydrate or ethylene glycol or a mixture thereof.

Example 16

A preparation method of graphene modification-based lead-free glass powder comprises the following steps: the lead-free glass frit prepared in any one of examples 1 to 4 was well mixed with the graphene oxide dispersion prepared in any one of examples 5 to 8, wherein the lead-free glass frit and the oxide were controlledThe mass ratio of graphene is 20:1, mixing and stirring are carried out for 30min, ultrasonic dispersion is carried out for 3h, stirring and mixing are carried out for 6h, uniform dispersion liquid of lead-free glass powder and graphene oxide is obtained, finally, the dispersion liquid is filtered by a PVDF membrane, residual organic solvent is removed by washing for multiple times by acetone, and finally, drying is carried out in a vacuum drying oven for 24h, so that the lead-free glass powder modified by the graphene oxide is obtained. Then placing the graphene oxide modified lead-free glass powder in a hydrogen atmosphere for a predetermined period of time, and controlling hydrogen H₂The flow rate of (a) is 20ml/min, so that the graphene oxide modified lead-free glass powder is reduced into the highly dispersed graphene modified lead-free glass powder.

Example 17

A preparation method of graphene modification-based lead-free glass powder comprises the following steps: fully mixing the lead-free glass powder prepared in any one of the embodiments 1 to 4 with the modified graphene oxide dispersion liquid prepared in any one of the embodiments 9 to 12, wherein the mass ratio of the lead-free glass powder to the modified graphene oxide in the modified graphene oxide dispersion liquid is controlled to be 2:1, mixing and stirring for 30min, performing ultrasonic dispersion for 3h, further stirring and mixing for 12h to obtain a uniform dispersion liquid of the lead-free glass powder and the modified graphene oxide, filtering the dispersion liquid by using a PVDF film, washing the dispersion liquid for multiple times by using acetone to remove residual organic solvent, and finally drying the dispersion liquid in a vacuum drying oven for 24h to obtain the lead-free glass powder modified by the modified graphene oxide. Then weighing a reducing agent and the modified graphene oxide modified lead-free glass powder according to a mass ratio of 4:1, dispersing the modified graphene oxide modified lead-free glass powder in the reducing agent for reaction to obtain a reduction dispersion liquid, then continuously stirring the reduction dispersion liquid on a magnetic stirrer at 70 ℃ for 24 hours, reducing the modified graphene oxide in the modified graphene oxide modified lead-free glass powder into modified graphene after full reaction, finally filtering the reduction dispersion liquid through a PVDF membrane with the pore diameter of 0.5 mu m, washing with ethanol for multiple times to remove residual reducing agent solvent, and drying in a vacuum drying oven for 24 hours to obtain the modified graphene modified lead-free glass powder, wherein the reducing agent is selected from ascorbic acid, sodium thiosulfate, hydrazine, dimethylhydrazine, hydrazine hydrate, ethylene glycol, diethylene glycol, and the like, Any one of N, N' -dicyclohexylcarbodiimide.

Example 18

A preparation method of graphene modification-based lead-free glass powder comprises the following steps: fully mixing the lead-free glass powder prepared in any one of the embodiments 1 to 4 with the modified graphene oxide dispersion liquid prepared in any one of the embodiments 9 to 12, wherein the mass ratio of the lead-free glass powder to the modified graphene oxide in the modified graphene oxide dispersion liquid is controlled to be 100:1, mixing and stirring for 20min, performing ultrasonic dispersion for 2h, further stirring and mixing for 1h to obtain a uniform dispersion liquid of the lead-free glass powder and the modified graphene oxide, filtering the dispersion liquid by using a PVDF film, washing the dispersion liquid for multiple times by using acetone to remove residual organic solvent, and finally drying the dispersion liquid in a vacuum drying oven for 24h to obtain the lead-free glass powder modified by the modified graphene oxide. Then weighing a reducing agent and the modified graphene oxide modified lead-free glass powder according to the mass ratio of 1:1, dispersing the modified graphene oxide modified lead-free glass powder in the reducing agent for reaction to obtain a reduction dispersion liquid, then continuously stirring the reduction dispersion liquid on a magnetic stirrer at 70 ℃ for 24 hours, reducing the modified graphene oxide in the modified graphene oxide modified lead-free glass powder into modified graphene after full reaction, finally filtering the reduction dispersion liquid through a PVDF membrane with the pore diameter of 0.5 mu m, washing with ethanol for multiple times to remove residual reducing agent solvent, and drying in a vacuum drying oven for 24 hours to obtain the modified graphene modified lead-free glass powder, wherein the reducing agent is selected from ascorbic acid, sodium thiosulfate, hydrazine, dimethylhydrazine, hydrazine hydrate, ethylene glycol, diethylene glycol, and the like, Any one of N, N' -dicyclohexylcarbodiimide.

Example 19

A preparation method of graphene modification-based lead-free glass powder comprises the following steps: fully mixing the lead-free glass powder prepared in any one of the embodiments 1 to 4 with the modified graphene oxide dispersion liquid prepared in any one of the embodiments 9 to 12, wherein the mass ratio of the lead-free glass powder to the modified graphene oxide in the modified graphene oxide dispersion liquid is controlled to be 50:1, mixing and stirring for 30min, performing ultrasonic dispersion for 3h, further stirring and mixing for 8h to obtain a uniform dispersion liquid of the lead-free glass powder and the modified graphene oxide, filtering the dispersion liquid by using a PVDF film, washing the dispersion liquid for multiple times by using acetone to remove residual organic solvent, and finally drying the dispersion liquid in a vacuum drying oven for 24h to obtain the lead-free glass powder modified by the modified graphene oxide. Then weighing a reducing agent and the modified graphene oxide modified lead-free glass powder according to the mass ratio of 2:1, dispersing the modified graphene oxide modified lead-free glass powder in the reducing agent for reaction to obtain a reduction dispersion liquid, then continuously stirring the reduction dispersion liquid on a magnetic stirrer at 70 ℃ for 24 hours, reducing the modified graphene oxide in the modified graphene oxide modified lead-free glass powder into modified graphene after full reaction, finally filtering the reduction dispersion liquid through a PVDF membrane with the pore diameter of 0.5 mu m, washing with ethanol for multiple times to remove residual reducing agent solvent, and drying in a vacuum drying oven for 24 hours to obtain the modified graphene modified lead-free glass powder, wherein the reducing agent is selected from ascorbic acid, sodium thiosulfate, hydrazine, dimethylhydrazine, hydrazine hydrate, ethylene glycol, diethylene glycol, and the like, A mixture of two of N, N' -dicyclohexylcarbodiimide.

Example 20

A preparation method of graphene modification-based lead-free glass powder comprises the following steps: fully mixing the lead-free glass powder prepared in any one of the embodiments 1 to 4 with the modified graphene oxide dispersion liquid prepared in any one of the embodiments 9 to 12, wherein the mass ratio of the lead-free glass powder to the modified graphene oxide in the modified graphene oxide dispersion liquid is controlled to be 20:1, mixing and stirring for 30min, performing ultrasonic dispersion for 3h, further stirring and mixing for 6h to obtain a uniform dispersion liquid of the lead-free glass powder and the modified graphene oxide, filtering the dispersion liquid by using a PVDF film, washing the dispersion liquid for multiple times by using acetone to remove residual organic solvent, and finally drying the dispersion liquid in a vacuum drying oven for 24h to obtain the lead-free glass powder modified by the modified graphene oxide. Then placing the modified graphene oxide modified lead-free glass powder in a hydrogen atmosphere for a predetermined period of time, and controlling hydrogen H₂The flow rate of (a) is 20ml/min, so that the modified graphene oxide modified lead-free glass powder is reduced to high-molecular weightThe lead-free glass powder modified by the dispersed modified graphene.

Example 21

A preparation method of an electronic paste of a solar cell comprises the following steps: weighing the following components in percentage by mass: 3% of graphene-modified lead-free glass powder, 82% of silver powder and 15% of organic carrier, wherein the silver powder is spherical, the particle size of the silver powder is 1 mu m, and the tap density is 3g/cm³The organic carrier is alcohol ester twelve, the graphene modification-based lead-free glass powder, the silver powder and the organic carrier are mixed and then placed on a three-roll machine to be fully and uniformly mixed to prepare the electronic paste for the solar cell, and the fineness of the paste is tested to be twelve<10 μm, a viscosity of 220Pa · s, and a thixotropic index of 5.9, wherein the graphene-modification based lead-free glass frit is the lead-free glass frit prepared in any one of examples 13 to 20.

Example 22

A preparation method of an electronic paste of a solar cell comprises the following steps: weighing the following components in percentage by mass: 5% of graphene-modified lead-free glass powder, 80% of silver powder and 15% of organic carrier, wherein the silver powder is spherical, the particle size of the silver powder is 2 mu m, and the tap density is 4g/cm³The organic carrier is terpineol, the graphene modification-based lead-free glass powder, the silver powder and the organic carrier are mixed and then placed on a three-roll machine to be fully and uniformly mixed, so that the electronic paste for the solar cell is prepared, and the fineness of the paste is tested to be terpineol<10 μm, a viscosity of 180Pa · s, and a thixotropic index of 4.9, wherein the graphene-modification based lead-free glass frit is the lead-free glass frit prepared in any one of examples 13 to 20.

Example 23

A preparation method of an electronic paste of a solar cell comprises the following steps: weighing the following components in percentage by mass: 5% of graphene-modified lead-free glass powder, 85% of silver powder and 10% of organic carrier, wherein the silver powder is spherical, the particle size of the silver powder is 4 micrometers, and the tap density is 6g/cm³The organic carrier is alcohol ester twelve, and the graphene-modification-based lead-free glass powder, the silver powder and the organic carrier are mixed and then placed on a three-roll machine to be fully and uniformly mixed to obtain the graphene-modification-based lead-free glass powderThe fineness of the electronic paste for the solar cell is tested to be<10 μm, a viscosity of 120Pa · s, and a thixotropic index of 3.6, wherein the graphene-modification based lead-free glass frit is the lead-free glass frit prepared in any one of examples 13 to 20.

As an application example, the solar cell electronic paste prepared by the invention is used for printing an electrode on the front surface of a polycrystalline silicon solar cell by a screen printing method; the specifications of the polycrystalline silicon solar cell piece are as follows: the side length is 156mm, the thickness is 190 +/-10 mu m, and the sheet resistance is 60-100 omega. The parameters of the screen printing plate for printing the electrode on the front surface of the polycrystalline silicon solar cell by the screen printing method are as follows: 320mm of aluminum frame outer diameter, 400 meshes of mesh, 20 mu m of wire diameter, 20 mu m of film thickness and 22N of tension; the width of the printed fine grid is generally 70-90 μm, the height is about 23 μm, and the photoelectric conversion efficiency of the polycrystalline silicon solar cell prepared by using the solar cell front silver paste described in each example is shown in the following table:

the group A is performance test parameters of a solar cell electrode prepared from the electronic paste for the solar cell prepared from the graphene-free lead-free glass powder in the prior art; the group B is performance test parameters of a solar cell electrode prepared from the electronic paste for the solar cell (three selected examples) prepared from the graphene-modified lead-free glass powder; wherein the group C is performance test parameters of a solar cell electrode prepared from the electronic paste for the solar cell (three selected examples) prepared from the modified graphene modified lead-free glass powder; therefore, the photoelectric conversion efficiency of the polycrystalline silicon solar cell prepared by the electronic paste for the solar cell prepared by the lead-free glass powder modified by the graphene can reach more than 18%.

The invention utilizes the excellent conductivity of grapheneThe glass powder has special properties of good dispersibility in some solvent matrixes, easy filling of a reticular structure in gaps between glass powder, good bonding force with a silicon substrate and the like, and a condensing agent method is adopted and specific NH is carried₂Modifying graphene by using a radical substance, modifying the surface of the graphene, mixing and stirring the modified graphene and the lead-free glass powder prepared by a melt quenching method, and performing ultrasonic dispersion, cooling, cleaning, filtering and vacuum drying to obtain the graphene-modified high-dispersion lead-free glass powder. Meanwhile, the invention utilizes a condensing agent method to modify the surface of graphene and prepares the graphene-modified high-dispersion lead-free glass powder based on the modified graphene, and the prepared lead-free glass powder has the unique advantages of environmental protection, high conductivity, stronger bonding force between the glass powder and a silicon substrate and the like when being applied to the conductive paste of the solar cell due to the advantages of simple process, mild condition, high functionalization degree, good dispersibility, high conductivity and the like.

The above description is only for the preferred embodiment of the present invention, and the technical solution of the present invention is not limited thereto, and any known modifications made by those skilled in the art based on the main technical idea of the present invention belong to the technical scope of the present invention, and the specific protection scope of the present invention is subject to the description of the claims.

Claims

1. The glass powder based on graphene modification is characterized in that graphene or modified graphene is modified on the surface of the glass powder through adsorption and bonding; the glass powder comprises the following components in percentage by mass: 30 to 55% of Bi₂O₃，10～35％TeO₂，5～15％ZnO，3～5％MgO，5-15％SiO₂，2～4％P₂O₅，5～15％B₂O₃，1～12％Al₂O₃And 0 to 5% of V₂O₅CaO and SnO₂At least one of; the graphene or the modified graphene is a few layers with the number of layers between 1 and 10Graphene;

modifying graphene on the surface of glass powder in the following way, and specifically comprising the following steps:

step (1), preparing graphene oxide with the following structure:

step (2), uniformly dispersing the graphene oxide prepared in the step (1) in an organic solvent to obtain a graphene oxide organic dispersion solution, wherein the weight percentage concentration of the graphene oxide in the organic dispersion solution is 0.05-5.0 wt%, and the organic solvent is at least one of alcohol ester dodeca, terpineol, tributyl citrate, triethanolamine, butyl carbitol, dimethyl glutarate, dimethyl adipate, dimethyl phthalate and oleic acid;

fully mixing the glass powder with the graphene oxide organic dispersion solution prepared in the step (2), adding the glass powder into the graphene oxide organic dispersion solution, mixing and stirring for 20-30min, ultrasonically dispersing for 2-3h, stirring and mixing for 1-12h to obtain a uniform dispersion liquid of the glass powder and the graphene oxide, modifying the graphene oxide on the surface of the glass powder through electrostatic adsorption and hydrogen bond action, filtering the dispersion liquid by using a PVDF (polyvinylidene fluoride) membrane, washing with ethanol or acetone for multiple times to remove residual organic solvent, and drying in a vacuum drying oven for 24h to obtain the graphene oxide modified glass powder, wherein the mass ratio of the glass powder to the graphene oxide dispersed in the graphene oxide organic dispersion solution is 2-100: 1;

reducing the glass powder modified by graphene oxide into glass powder modified by graphene oxide, specifically reducing the glass powder modified by graphene oxide into glass powder modified by graphene oxide by using a reducing agent or a hydrogen atmosphere, wherein the mass ratio of the reducing agent to the glass powder modified by graphene oxide is 1-4:1 when the reducing agent is used for reduction, and the reducing agent is selected from at least one of ascorbic acid, sodium thiosulfate, hydrazine, dimethylhydrazine, hydrazine hydrate, ethylene glycol, diethylene glycol and N, N' -dicyclohexylcarbodiimide, wherein the flow rate of hydrogen is controlled to be 10.0-30mL/min when the reducing agent is used for reduction in the hydrogen atmosphere;

the method for modifying the modified graphene on the surface of the glass powder comprises the following steps:

step (1), preparing graphene oxide with the following structure:

step (3), preparing a modified graphene oxide dispersion liquid, specifically, uniformly dispersing a modifier in the graphene oxide organic dispersion liquid prepared in the step (2), wherein the mass ratio of the modifier to the graphene oxide dispersed in the graphene oxide organic dispersion liquid prepared in the step (2) is 2-15:1, and the modifier is selected from at least one of 3- (aminopropyl) triethoxysilane, 3- (trimethoxysilyl) -1-propylamine, 3-aminopropylmethyldiethoxysilane, diethylenetriaminopropyltrimethoxysilane, tert-butylaminotrimethoxysilane and 4-amino-3, 3-dimethylbutyltrimethoxysilane;

step (4), purifying the modified graphene oxide dispersion liquid, filtering the modified graphene oxide dispersion liquid prepared in the step (3) through a PVDF membrane with the pore diameter of 0.4-0.6 mu m, washing the modified graphene oxide dispersion liquid with ethanol or acetone for multiple times to remove residual modifier, finally drying the modified graphene oxide dispersion liquid in a vacuum drying oven for 24 hours to obtain modified graphene oxide dry powder, then uniformly dispersing the prepared modified graphene oxide dry powder in an organic solvent again to obtain the purified modified graphene oxide dispersion liquid, wherein the weight percentage concentration of the modified graphene oxide dry powder in the dispersion liquid is 1-10.0 wt%, and the organic solvent is selected from at least one of dodecyl ester, terpineol, tributyl citrate, triethanolamine, butyl carbitol, dimethyl glutarate, dimethyl adipate, dimethyl phthalate and oleic acid;

step (5), fully mixing glass powder with the purified modified graphene oxide dispersion liquid prepared in the step (4), specifically adding the glass powder into the purified modified graphene oxide dispersion liquid, mixing and stirring for 20-30min, ultrasonically dispersing for 2-3h, stirring and mixing for 1-12h to obtain a mixed dispersion liquid of glass powder and modified graphene oxide, the modified graphene oxide is modified on the surface of the glass powder through electrostatic adsorption and hydrogen bond action, and finally the mixed dispersion liquid is filtered by a PVDF membrane, washing with ethanol or acetone for multiple times to remove residual organic solvent, drying in a vacuum drying oven for 24h to obtain modified graphene oxide modified glass powder, wherein the mass ratio of the glass powder to the modified graphene oxide dry powder dispersed in the modified graphene oxide dispersion liquid is 2-100: 1;

and (6) reducing the modified graphene oxide modified glass powder obtained in the step (5) into modified graphene modified glass powder, specifically reducing the modified graphene oxide modified glass powder into modified graphene modified glass powder by using a reducing agent or hydrogen atmosphere, wherein the mass ratio of the reducing agent to the modified graphene oxide modified glass powder is 1-4:1 when the reducing agent is used for reduction, the reducing agent is selected from at least one of ascorbic acid, sodium thiosulfate, hydrazine, dimethylhydrazine, hydrazine hydrate, ethylene glycol, diethylene glycol and N, N' -dicyclohexylcarbodiimide, and the flow rate of hydrogen is controlled to be 10.0-30mL/min when the reducing agent is used for reduction in the hydrogen atmosphere.

2. The preparation method of the glass powder based on graphene modification is characterized by comprising the following steps:

the method comprises the following steps: preparing the glass powder, specifically weighing the following components in percentage by mass: 30 to 55% of Bi₂O₃，10～35％TeO₂，5～15％ZnO，3～5％MgO，5-15％SiO₂，2～4％P₂O₅，5～15％B₂O₃，1～12％Al₂O₃And 0 to 5% of V₂O₅CaO and SnO₂At least one of; then, uniformly mixing the weighed components, smelting in a high-temperature electric furnace, taking out, quenching in distilled water to room temperature to obtain coarse glass powder, and further crushing the coarse glass powder into glass powder with the required particle size;

step two: preparing an organic graphene oxide dispersion solution, namely firstly preparing graphene oxide with the following structure:

uniformly dispersing the graphene oxide in an organic solvent to obtain a graphene oxide organic dispersion solution, wherein the weight percentage concentration of the graphene oxide in the organic dispersion solution is 0.05-5.0 wt%, and the organic solvent is selected from at least one of alcohol ester twelve, terpineol, tributyl citrate, triethanolamine, butyl carbitol, dimethyl glutarate, dimethyl adipate, dimethyl phthalate and oleic acid;

step three: uniformly dispersing the glass powder prepared in the first step into the graphene oxide organic dispersion solution prepared in the second step for full reaction, specifically, adding the glass powder into the graphene oxide organic dispersion solution, mixing and stirring for 20-30min, performing ultrasonic dispersion for 2-3h, further stirring and mixing for 1-12h to obtain a uniform dispersion solution of the glass powder and the graphene oxide, modifying the graphene oxide on the surface of the glass powder through electrostatic adsorption and hydrogen bond action, finally filtering the dispersion solution by using a PVDF (polyvinylidene fluoride) membrane, washing with ethanol or acetone for multiple times to remove residual organic solvent, and finally drying in a vacuum drying oven for 24h to obtain the graphene oxide modified glass powder, wherein the mass ratio of the glass powder to the graphene oxide dispersed in the graphene oxide organic dispersion solution is 2-100: 1;

step four: and reducing the graphene oxide modified glass powder obtained in the third step to obtain graphene oxide modified glass powder, specifically reducing the graphene oxide modified glass powder into graphene oxide modified glass powder by using a reducing agent or a hydrogen atmosphere, wherein the mass ratio of the reducing agent to the graphene oxide modified glass powder is 1-4:1 when the reducing agent is used for reduction, the reducing agent is selected from at least one of ascorbic acid, sodium thiosulfate, hydrazine, dimethylhydrazine, hydrazine hydrate, ethylene glycol, diethylene glycol and N, N' -dicyclohexylcarbodiimide, and the flow of hydrogen is controlled to be 10.0-30mL/min when the reducing agent is used for reduction in the hydrogen atmosphere.

3. The preparation method of the glass powder based on graphene modification is characterized by comprising the following steps:

step three: modifying the graphene oxide organic dispersion solution prepared in the second step to obtain a modified graphene oxide dispersion solution; the method specifically comprises the following steps:

(1) uniformly dispersing a modifier in the graphene oxide organic dispersion solution prepared in the second step to obtain a modified graphene oxide dispersion solution, wherein the mass ratio of the modifier to the graphene oxide dispersed in the graphene oxide organic dispersion solution is 2-15:1, and the modifier is selected from at least one of 3- (aminopropyl) triethoxysilane, 3- (trimethoxysilyl) -1-propylamine, 3-aminopropyl methyldiethoxysilane, diethylenetriaminopropyl trimethoxysilane, tert-butyl propylamino trimethoxysilane and 4-amino-3, 3-dimethylbutyl trimethoxysilane;

(2) further purifying the prepared modified graphene oxide dispersion liquid, filtering the modified graphene oxide dispersion liquid through a PVDF membrane with the aperture of 0.4-0.6 mu m, washing the modified graphene oxide dispersion liquid for multiple times by using ethanol or acetone to remove residual modifier, finally drying the modified graphene oxide dispersion liquid in a vacuum drying oven for 24 hours to obtain modified graphene oxide dry powder, and then uniformly dispersing the prepared modified graphene oxide dry powder in an organic solvent again to obtain the purified modified graphene oxide dispersion liquid, wherein the weight percentage concentration of the modified graphene oxide dry powder in the dispersion liquid is 1-10.0 wt%, and the organic solvent is at least one selected from the group consisting of dodecyl alcohol, terpineol, tributyl citrate, triethanolamine, butyl carbitol, dimethyl glutarate, dimethyl adipate, dimethyl phthalate and oleic acid;

step four: uniformly dispersing the glass powder prepared in the first step into the modified graphene oxide dispersion liquid prepared in the third step for full reaction, specifically adding the glass powder into the purified modified graphene oxide dispersion liquid, mixing and stirring for 20-30min, ultrasonically dispersing for 2-3h, stirring and mixing for 1-12h to obtain a mixed dispersion liquid of glass powder and modified graphene oxide, the modified graphene oxide is modified on the surface of the glass powder through electrostatic adsorption and hydrogen bond action, and finally the mixed dispersion liquid is filtered by a PVDF membrane, washing with ethanol or acetone for multiple times to remove residual organic solvent, drying in a vacuum drying oven for 24h to obtain modified graphene oxide modified glass powder, wherein the mass ratio of the glass powder to the modified graphene oxide dry powder dispersed in the modified graphene oxide dispersion liquid is 2-100: 1;

step five: reducing the modified graphene oxide-modified glass powder obtained in the fourth step to obtain modified graphene oxide-modified glass powder; the method specifically comprises the step of reducing modified graphene oxide modified glass powder into modified graphene oxide modified glass powder by using a reducing agent or a hydrogen atmosphere, wherein the mass ratio of the reducing agent to the modified graphene oxide modified glass powder is 1-4:1 when the reducing agent is used for reduction, the reducing agent is selected from at least one of ascorbic acid, sodium thiosulfate, hydrazine, dimethylhydrazine, hydrazine hydrate, ethylene glycol, diethylene glycol and N, N' -dicyclohexylcarbodiimide, and the flow rate of hydrogen is controlled to be 10.0-30mL/min when the reducing agent is used for reduction.

4. The electronic paste is characterized by comprising the following components in percentage by mass: 3-5% of glass powder, 80-85% of silver powder and 10-15% of organic carrier, wherein the glass powder is the graphene modification based glass powder disclosed by claim 1 or the graphene modification based glass powder prepared by the preparation method disclosed by any one of claims 2-3.