阅读说明：本技术 一种用于快速制绒的制绒添加剂及应用 (Texturing additive for rapid texturing and application ) 是由 周树伟 张丽娟 陈培良 于 2021-08-19 设计创作，主要内容包括：本发明公开了一种用于快速制绒的制绒添加剂及应用,所述制绒添加剂包括如下质量百分比含量的各组分：成核剂0.5%～10%,绒面催化剂1%～10%,表面活性剂0.01%～0.05%,脱泡剂0.05%～0.5%,余量为去离子水。本发明的制绒添加剂能够实现制绒时间缩短至240s,与现有制绒添加剂的单面腐蚀深度2.5um相比,本发明制绒添加剂的单面腐蚀深度达1.5um时便可以实现金字塔的完全生长,可获得2um的绒面尺寸,并具有良好的降低反射率的效果。(The invention discloses a texturing additive for rapid texturing and application thereof, wherein the texturing additive comprises the following components in percentage by mass: 0.5-10% of nucleating agent, 1-10% of textured surface catalyst, 0.01-0.05% of surfactant, 0.05-0.5% of defoaming agent and the balance of deionized water. The texturing additive can shorten the texturing time to 240s, and compared with the single-side corrosion depth of 2.5um of the existing texturing additive, the single-side corrosion depth of the texturing additive can achieve the complete growth of pyramids when reaching 1.5um, the size of a 2um textured surface can be obtained, and the effect of reducing the reflectivity is good.)

1. The additive for rapid texturing is characterized by comprising the following components in percentage by mass: 0.5-10% of nucleating agent, 1-10% of textured surface catalyst, 0.01-0.05% of surfactant, 0.05-0.5% of defoaming agent and the balance of deionized water.

2. A texturing additive for rapid texturing according to claim 1, wherein the nucleating agent is selected from one or two of hydrolyzed polyacrylonitrile sodium salt and hydrolyzed polyacrylonitrile ammonium salt.

3. The additive for rapid texture surface according to claim 1 or 2, wherein the texture surface catalyst is choline or choline hydroxide.

4. A texturing additive for rapid texturing according to claim 3 wherein the surfactant is selected from one or more of sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium hexadecyl sulfate, sodium dodecyl benzene sulfonate, sodium tetradecyl benzene sulfonate, sodium hexadecyl benzene sulfonate.

5. A additive for rapid texture etching according to claim 1 or 4 wherein the de-foaming agent is selected from a toluene diamine polyether polyol.

6. The additive for rapid texture surface formation according to claim 5, wherein the viscosity of the defoaming agent is 1100 to 12000 mPa.s.

7. A quick-acting texturing solution, which is characterized by containing an alkali solution and the texturing additive of any one of claims 1 to 6, wherein the mass ratio of the texturing additive to the alkali solution is 0.5-2.5: 100.

8. The fast-texturing solution according to claim 7, wherein the alkali solution is 0.2 to 2wt% of an aqueous sodium hydroxide solution or an aqueous potassium hydroxide solution.

9. A method for rapidly texturing a single crystal silicon wafer, characterized in that the texturing solution of claim 7 or 8 is used to texture the surface of the single crystal silicon wafer.

10. The method for rapidly texturing a single crystal silicon wafer according to claim 9, comprising the steps of:

(1) preparing a texturing additive: adding 0.5-10% of nucleating agent, 1-10% of suede catalyst, 0.01-0.05% of surfactant and 0.05-0.5% of defoaming agent into the balance of deionized water, and uniformly mixing to prepare a suede making additive;

(2) preparing a texturing solution: adding the texturing additive prepared in the step (1) into an alkaline solution, and uniformly mixing to prepare a texturing solution; the mass ratio of the texturing additive to the aqueous alkali is 0.5-2.5: 100;

(3) texturing: and (3) immersing the monocrystalline silicon wafer into the texturing solution prepared in the step (2) for surface texturing, wherein the texturing temperature is 75-85 ℃, and the texturing time is 240-290 s.

Technical Field

The invention relates to the technical field of photovoltaics, in particular to a texturing additive for rapid texturing and application thereof.

Background

With the rapid development of the photovoltaic industry, large-scale production expansion is performed on upstream silicon materials and silicon wafers, midstream cells or downstream components, wherein the production expansion speed of the cells is remarkable, so that the upstream silicon wafers are short of supply and demand. Cell manufacturers are beginning to develop a thinning trend within the entire photovoltaic industry in order to spread costs, and some manufacturers are beginning to use silicon wafers with a thickness of 140um, so that it is expected that in the near future, the thinning will become the industry standard and even thinner silicon wafers may be developed for photovoltaic cells.

The manufacturing links of the cell piece comprise a plurality of working procedures of texturing, diffusion, etching, oxidation, film coating, silk-screen printing, sintering and the like, and in order to minimize the weight reduction of the silicon chip in the whole manufacturing link as far as possible, the texturing is taken as the first working procedure to be challenged by the technology of thinning the silicon chip. Texturing is to generate texture on the surface of a silicon wafer through alkaline etching, so that the solar absorption rate of the silicon wafer is improved, and the efficiency of a battery is improved. It is well known that higher cell efficiencies yield better power generation benefits, which has prompted manufacturers to continually seek better texturing additives to aid in alkaline etching during wet texturing to achieve lower etch depths and lower reflectivity, i.e., better surface "texturing," with minimal texturing time.

In the wet-method texturing process, the texturing additive is limited by the reaction rate of a silicon wafer and alkali, the growth rate of textured pyramids and the consumption of chemicals, so that the silicon wafer can only achieve the complete growth of pyramids or the optimization of the texturing surface until reaching a certain corrosion depth, the relatively proper texturing size which can be achieved by the existing texturing additive is 1.5-3 um, and even though some texturing additives can achieve rapid texturing in a relatively short time, for example, Chinese patent CN111501105A, a certain corrosion depth is required, and the problem that the pyramid growth is not complete below the corrosion depth usually occurs, so that the texturing size is too small (less than 1 um) and the reflectivity is higher is solved. Therefore, a texturing additive which can realize rapid texturing under the condition of extremely low corrosion depth, has appropriate textured surface size and low reflectivity needs to be developed, and is a development aid for the industry.

Disclosure of Invention

The invention aims to provide a texturing additive for rapid texturing and application thereof, wherein the texturing additive can shorten the texturing time and can obtain a texturing sheet with low corrosion depth and low reflectivity.

According to a first aspect of the invention, a texturing additive for rapid texturing is provided, which comprises the following components in percentage by mass: 0.5-10% of nucleating agent, 1-10% of textured surface catalyst, 0.01-0.05% of surfactant, 0.05-0.5% of defoaming agent and the balance of deionized water.

Preferably, the nucleating agent is selected from one or two of hydrolyzed polyacrylonitrile sodium salt and hydrolyzed polyacrylonitrile ammonium salt.

Preferably, the textured catalyst is choline or choline hydroxide.

Preferably, the surfactant is selected from one or more of sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium hexadecyl sulfate, sodium dodecyl benzene sulfonate, sodium tetradecyl benzene sulfonate and sodium hexadecyl benzene sulfonate.

Preferably, the defoamer is selected from toluene diamine polyether polyols.

Preferably, the viscosity of the defoaming agent is 1100-12000 mPa.s.

According to a second aspect of the invention, a fast-texturing solution is provided, which comprises an alkali solution and the above-mentioned texturing additive, wherein the mass ratio of the texturing additive to the alkali solution is 0.5-2.5: 100.

Preferably, the alkali solution is 0.2-2 wt% of sodium hydroxide aqueous solution or potassium hydroxide aqueous solution.

According to a third aspect of the invention, a rapid texturing method of a monocrystalline silicon wafer is provided, wherein the texturing liquid is utilized to perform surface texturing on the monocrystalline silicon wafer.

Preferably, the method for rapidly texturing the monocrystalline silicon wafer comprises the following steps:

(1) preparing a texturing additive: adding 0.5-10% of nucleating agent, 1-10% of suede catalyst, 0.01-0.05% of surfactant and 0.05-0.5% of defoaming agent into the balance of deionized water, and uniformly mixing to prepare a suede making additive;

(2) preparing a texturing solution: adding the texturing additive prepared in the step (1) into an alkaline solution, and uniformly mixing to prepare a texturing solution; the mass ratio of the texturing additive to the aqueous alkali is 0.5-2.5: 100;

(3) texturing: and (3) immersing the monocrystalline silicon wafer into the texturing solution prepared in the step (2) for surface texturing, wherein the texturing temperature is 75-85 ℃, and the texturing time is 240-290 s.

The texturing additive provided by the invention is prepared from hydrolyzed polyacrylonitrile sodium salt and hydrolyzed polyacrylonitrile ammonium salt serving as nucleating agents, and an anionic polymer obtained by alkaline hydrolysis of polyacrylonitrile waste, wherein the molecular chain contains strong polar groups such as amide groups, carboxyl groups and nitrile groups, and the strong polar groups and Si-H bonds on the surface of a silicon wafer form a strong hydrogen bonding effect, so that the anionic polymer can be well adsorbed on the surface of the silicon wafer, and has good texturing performance, and a good texturing substrate can be formed. In order to solve the problem, the texturing additive of the invention is added with a textured catalyst choline or choline hydroxide, the molecules of the textured catalyst choline or choline hydroxide contain active-OH and have strong alkalinity, and N with positive charge enables the textured catalyst to have strong adsorbability on the surface of a silicon wafer, thereby generating synergistic effect with alkali and promoting OH^-The silicon wafer surface texture etching agent is combined with the silicon wafer surface to accelerate the texture etching reaction rate, so that the reaction can enable the pyramids to grow and form completely when the etching depth is smaller, but the reaction does not stay in the growth process that the pyramids are high in density but the texture is small, and the reflectivity of the textured silicon wafer is lower.

After the suede catalyst choline or choline hydroxide is added into the texturing additive, bubbles on the surface of the silicon wafer are generated faster, so that the requirement on the removal rate of the bubbles is higher. According to the invention, the toluene diamine polyether polyol with the viscosity of 1100-12000 mPa.s is selected as the defoaming agent, so that the surface tension is very low, and bubbles on the surface of the silicon wafer can be rapidly removed. Although the defoaming agent has good defoaming capability, the basic appearance problems such as bubble marks and the like cannot be remained on the surface of the silicon wafer after texturing, the situation of poor uniformity still exists, particularly, the silicon wafer etching depth is low, the bubbles generated by the reaction on the surface of the silicon wafer are quickly removed, and the bubbles on the lower part can influence the surface of the silicon wafer on the upper part, so that the texturing appearance needs to be optimized by matching the surfactant.

The surfactant is selected from one or more of sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium hexadecyl sulfate, sodium dodecyl benzene sulfonate, sodium tetradecyl benzene sulfonate and sodium hexadecyl benzene sulfonate, and has the function of supplementing wool while being used as an appearance blender. And a small amount of surfactant is adsorbed on the surface of the silicon wafer, so that the nucleating agent is more uniformly distributed, and a good appearance can be obtained at a high corrosion rate.

Compared with the prior art, the invention has the following advantages:

(1) the texturing additive can shorten the texturing time to 240 s;

(2) compared with the single-side corrosion depth of 2.5um of the existing texturing additive, the single-side corrosion depth of the texturing additive can achieve the complete growth of pyramids when reaching 1.5um, the size of the textured surface of 2um can be obtained, and the effect of reducing the reflectivity is good.

Drawings

FIG. 1 is a textured topography obtained in example 1 of the present invention.

Detailed Description

The technical solution of the present invention is further described below with reference to the accompanying drawings and examples.

Example 1

According to the mass percentage, 5 parts of hydrolyzed polyacrylonitrile sodium salt, 2 parts of choline, 0.02 part of sodium dodecyl sulfate, 0.15 part of toluene diamine polyether polyol with the viscosity of 12000 mPa.s and 92.83 parts of deionized water are mixed and stirred uniformly to prepare a texturing additive; adding a texturing additive, sodium hydroxide and deionized water into the texturing tank body according to the mass ratio of 0.7:1.2:100 in sequence, and uniformly stirring to prepare a texturing solution; and then putting a silicon wafer into the reactor for texturing, wherein the texturing temperature is 80 ℃, and the reaction time is 240 s.

Example 2

According to the mass percentage, 5 parts of hydrolyzed polyacrylonitrile sodium salt, 8 parts of choline, 0.02 part of sodium dodecyl sulfate, 0.4 part of toluene diamine polyether polyol with the viscosity of 3500 mPa.s and 86.58 parts of deionized water are mixed and stirred evenly to prepare a texturing additive; adding a texturing additive, sodium hydroxide and deionized water into the texturing tank body according to the mass ratio of 0.7:0.4:100 in sequence, and uniformly stirring to prepare a texturing solution; and then putting a silicon wafer into the reactor for texturing, wherein the texturing temperature is 80 ℃, and the reaction time is 240 s.

Example 3

According to the mass percentage, 2.5 parts of hydrolyzed polyacrylonitrile sodium salt, 2.5 parts of hydrolyzed polyacrylonitrile ammonium salt, 8 parts of choline, 0.025 part of sodium dodecyl sulfate, 0.4 part of toluene diamine polyether polyol with the viscosity of 3500 mPa.s and 86.575 parts of deionized water are mixed and stirred evenly to prepare a texturing additive; adding a texturing additive, sodium hydroxide and deionized water into the texturing tank body according to the mass ratio of 0.7:0.3:100 in sequence, and uniformly stirring to prepare a texturing solution; and then putting a silicon wafer into the reactor for texturing, wherein the texturing temperature is 80 ℃, and the reaction time is 270 s.

Example 4

Mixing 5 parts of hydrolyzed polyacrylonitrile ammonium salt, 2 parts of choline, 0.01 part of sodium dodecyl sulfate, 0.015 part of sodium dodecyl benzene sulfonate, 0.15 part of toluene diamine polyether polyol with the viscosity of 8000 mPa.s and 92.825 parts of deionized water according to the mass percentage, and uniformly stirring to prepare a texturing additive; adding a texturing additive, sodium hydroxide and deionized water into the texturing tank body according to the mass ratio of 0.7:1:100 in sequence, and uniformly stirring to prepare a texturing solution; then putting the silicon wafer into the reactor for texturing, wherein the texturing temperature is 80 ℃, and the reaction time is 290 s.

Comparative example

Adding a texturing additive (disclosed in Chinese patent CN 111501105A), sodium hydroxide and deionized water into a texturing tank body according to the mass ratio of 0.7:1.2:100 in sequence, and uniformly stirring to prepare a texturing solution; and then putting a silicon wafer into the reactor for texturing, wherein the texturing temperature is 80 ℃, and the reaction time is 300 s.

The texturing sheets obtained in examples 1 to 4 and the comparative example were weighed, the etching depth was calculated, and a reflectance test was performed using an NXT Helios-rc reflectance tester, the test results of which are shown in table 1.

TABLE 1 etch depth and reflectance for examples 1-4 and comparative examples

As can be seen from Table 1, the texturing additive of the present invention provides significantly lower etch depths with good antireflecting effects. As can be seen from figure 1, the pyramid suede has been fully grown and formed, the size of the suede is about 2um, and very small unformed suede does not appear.