KR20150002515A - Transparent substrate having an anti-reflective multilayered coating thereon and method for preparing the same - Google Patents

Abstract

The present invention provides a transparent substrate for a solar cell and a production method thereof more enhancing durability and productivity while having a wide band (380-1100 nm) anti-reflectivity, which, as a transparent substrate applied to the outermost surface of the solar cell, improve transmissivity in a visible ray and a near-infrared ray area whereas lowering transmissivity in an infrared ray area causing degradation of a solar cell module, thereby contributing to efficiency improvement of the solar cell. The present invention relates to a transparent substrate having an anti-reflective coating layer including a transparent base material; a first coating layer formed with a first refractive index on the transparent base material; a second coating layer formed with a second refractive index on the first coating layer; a third coating layer formed with a third refractive index on the second coating layer; and a fourth coating layer formed with a fourth refractive index on the third coating layer and where the first refractive index is greater than the second refractive index and the third refractive index is greater than the fourth refractive index. The present invention has transmissivity higher than the transparent base material before forming the first, the second, the third and the fourth coating layer in a wavelength range of 380-1,100 nm and lower than the transparent base material before forming the first, the second, the third and the fourth coating layer in a wavelength range of 1,100-2,500 nm.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transparent substrate having an antireflection coating layer and a method of manufacturing the same.

The present invention relates to a transparent substrate having an antireflection multilayer coating with improved transmission performance and durability, and a method of manufacturing the same. For example, a transparent substrate having an antireflection multilayer coating applicable to a light receiving surface of a solar cell, .

The antireflective coating is a coating technique for preventing reflections up to visible light, that is, from 380 to 780 nm, originally developed as a technique started from the use of a frame, a lens, a watch, and a display device. Such antireflective coatings typically consist of a single film of material having a refractive index between the refractive index of the substrate (usually 1.52 for glass) and the refractive index of air (1.0).

In a transparent substrate for a solar cell, such as a solar cell cover glass, it is necessary to increase not only the visible light region but also the transmittance to the near infrared region (~ 1,100 nm) because the wavelength band of the light absorbed by the solar cell is wider than the visible light region . Therefore, in order to increase the conversion efficiency of the solar cell, the transmittance of the sunlight passing through the outermost transparent substrate of the solar cell should be improved in the wide band (380 to 1,100 nm).

In order to improve the solar light transmittance of such a wide band region, an antireflection coating made of a single layer of porous silicon oxide is conventionally formed on the outer surface of the outermost glass for a solar cell. The pores provided by this porous silicon oxide serve to lower the refractive index of the silicon oxide. However, such a monolayer coating has insufficient durability and chemical resistance to moisture, and is also poor in scratch resistance. Such a porous silicon oxide coating layer is usually formed using a sol-gel method, and it is difficult to obtain a uniform thin film when it is prepared by spraying, dipping, or roll coating method There is a disadvantage.

Alternatively, a method is known in which the outer surface of the glass is etched with a chemical such as hydrofluoric acid to form porous silicon oxide thinly on the glass. However, this method takes a long time to etch, resulting in a significant decrease in productivity, an uneven glass surface, and environmental problems due to the use of hydrofluoric acid.

Korean Patent Laid-Open No. 10-2008-0089351 discloses an antireflection film by a multilayer coating. However, when one of the high refractive index materials constituting the multi-layer coating disclosed in the above patent document is Si ₃ N ₄ , there is a problem that the bonding strength with glass is poor. In the case of SnO ₂ , Therefore, there is a problem in the durability of the solar cell to be used on the outer surface of the solar cell.

[Prior Art Literature]

[Patent Literature]

Korean Patent Publication No. 10-2008-0089351

Disclosure of Invention Technical Problem [8] The present invention has been made to solve the above problems of the prior art, and it is an object of the present invention to provide a transparent substrate which is applied to the outermost surface of a solar cell and which can improve the transmittance of visible light and near infrared rays, (380 ~ 1,100nm) antireflective property which contributes to the improvement of the efficiency of the solar cell by lowering the transmittance of the infrared region causing the solar cell and the manufacturing method thereof.

According to an aspect of the present invention,

Transparent substrate;

A first coating layer formed on the transparent substrate at a first refractive index, the first coating layer comprising titanium oxynitride;

A second coating layer formed on the first coating layer at a second refractive index;

A third coating layer formed on the second coating layer at a third refractive index; And

And a fourth coating layer formed on the third coating layer at a fourth refractive index,

Wherein the first refractive index is greater than the second refractive index and the third refractive index is greater than the fourth refractive index.

In this case, it is preferable that the first refractive index is 2.0 to 2.5, the second refractive index is 1.3 to 1.6, the third refractive index is 1.9 to 2.3, and the fourth refractive index is 1.3 to 1.6.

In this case, the first coating layer may have a thickness of 5 to 30 nm, the second coating layer may have a thickness of 20 to 50 nm, the third coating layer may have a thickness of 100 to 180 nm, and the fourth coating layer may have a thickness of 70 to 110 nm.

Further, it is preferable that the third coating layer comprises at least one nitride selected from silicon nitride, silicon aluminum nitride.

Further, it is preferable that the second coating layer and the fourth coating layer include at least one material selected from silicon oxide, silicon oxynitride, silicon oxycarbide, and silicon-aluminum mixed oxide.

Further, the transparent substrate exhibits an average transmittance of 92% or more in a wavelength range of 380 to 1,100 nm.

The transparent substrate has a higher transmittance than the transparent substrate before forming the first, second, third and fourth coating layers in the wavelength range of 380 to 1,100 nm, and the first, second, third, and fourth transparent substrates in the wavelength range of 1,100 nm to 2,500 nm. And an antireflection coating layer having a lower transmittance than that of the transparent substrate before forming the coating layer.

According to another aspect of the present invention,

(1) forming a first coating layer having a refractive index of 2.0 to 2.5 on a transparent substrate and comprising titanium oxynitride;

(2) forming a second coating layer having a refractive index of 1.3 to 1.6 on the first coating layer;

(3) forming a third coating layer having a refractive index of 1.9 to 2.3 on the second coating layer; And

(4) forming a fourth coating layer having a refractive index of 1.3 to 1.6 on the third coating layer.

At this time, it is preferable to continuously form each coating layer by a magnetron sputtering method.

Another aspect of the present invention provides a solar cell module including the transparent substrate described above.

At this time, the solar cell may be one solar cell selected from the group consisting of crystalline silicon, amorphous silicon thin film, dye sensitized type, CIGS (CuInGaSe) type, CdTe type, GaAs type or III- have.

According to the present invention, the adhesion and durability of the antireflective coating layer and glass are excellent, the transmittance is increased in the visible light-near infrared ray wavelength range (380 nm to 1,100 nm), the transmittance is lowered in the long wavelength range including far- It is possible to manufacture a broadband antireflective transparent substrate which can increase the efficiency of the cell by increasing the transmittance of the visible light and the near infrared region by increasing the solar energy absorption amount.

Further, as the production of the antireflection coating layer becomes faster, the broadband antireflection transparent substrate can be manufactured with excellent productivity and reduced cost.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic view of a layer construction of a glass having on its surface a four layer antireflective multilayer coating according to one embodiment of the present invention,
2 is a graph of transmittance according to wavelengths of an embodiment and a comparative example of the present invention.

Before describing the present invention in detail, it is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the invention, which is defined solely by the appended claims. shall. All technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art unless otherwise stated.

Throughout the description and claims, unless the context requires otherwise, the word "comprise" is intended to include the stated article, step or group of articles, and steps; Does not exclude the addition of an article, step, or group of articles or a group of steps.

On the contrary, the various embodiments of the present invention can be combined with any other embodiments as long as there is no clear counterpoint. In particular, any feature that is indicated to be advantageous or advantageous may be combined with any other feature or feature that is indicated to be advantageous or advantageous.

The transparent substrate having the antireflection coating layer according to the present invention includes a transparent substrate, a first coating layer, a second coating layer, a third coating layer, and a fourth coating layer.

1. Transparent substrate

As the transparent substrate on which the antireflective multilayer coating according to the present invention can be formed, a glass substrate or a transparent plastic substrate may be used. For example, plastic substrates can be used without limitation as long as antireflective multilayer coatings can be formed, and polycarbonate (PC), polymethylmethacrylate (PMMA) can be used as a non-limiting list.

In the case of glass substrates, for example, low-iron patterned glass, low-iron float glass, and transparent conductive film for general glass and solar cells such as soda lime glass for architectural or automobile use, Oxide, TCO) glass and the like can be used without limitation. In addition, a surface texture treatment or reinforced or partially reinforced glass may be used if necessary.

There is no particular limitation on the thickness of the transparent substrate, and the thickness can be freely selected within a range of 1 mm to 5 mm depending on the purpose of use.

2. First coating layer

The first coating layer included in the antireflective multilayer coating according to the present invention is formed on a transparent substrate and has a first refractive index and a first thickness.

The first refractive index is preferably 2.0 to 2.5. The first coating layer may comprise titanium oxynitride. The first thickness is preferably selected suitably in the range of 5 to 30 nm, more preferably 5 to 15 nm.

Titanium oxynitride can be represented by the formula TiO _a N _b and there is no particular limitation on the ratio of oxygen to nitrogen relative to titanium, a may be appropriately selected from 25 to 35 wt%, b is from 65 to 75 wt% %. ≪ / RTI > More preferably TiO _{0 .3} N _{0. 7,} but the present invention is not limited to these ratios.

3. Second coating layer

The second coating layer included in the antireflective multilayer coating according to the present invention is formed on the first coating layer and has a second refractive index and a second thickness.

The second refractive index can be appropriately selected within a refractive index of 1.3 to 1.6, more preferably 1.4 to 1.5.

The second coating layer may comprise at least one oxide selected from silicon oxides, silicon oxynitrides, silicon oxycarbides and silicon-aluminum mixed oxides. The mixed oxides have the advantage of improving the durability, especially the chemical resistance, compared with pure silicon oxide (SiO ₂ ). The ratio of each of silicon and aluminum does not increase the refractive index of the layer excessively, Can be adjusted accordingly.

The second thickness may be appropriately selected within the range of 20 to 120 nm, preferably 20 to 50 nm, and more preferably 30 to 40 nm.

4. Third coating layer

The third coating layer included in the antireflective multilayer coating according to the present invention is formed on the second coating layer, and has a third refractive index and a third thickness.

The third refractive index can be selected from the refractive indexes of 1.9 to 2.3, more preferably 1.9 to 2.1.

The third coating layer may include one or more nitrides selected from silicon nitride, silicon-aluminum nitride, and aluminum nitride.

It is preferable that the third thickness is suitably selected within the range of 100 to 180 nm.

5. Fourth coating layer

The fourth coating layer included in the antireflective multilayer coating according to the present invention is formed on the third coating layer and has a fourth refractive index and a fourth thickness.

The fourth refractive index can be appropriately selected within a refractive index of 1.3 to 1.6, more preferably 1.4 to 1.5, as in the case of the second coating layer.

The fourth coating layer may comprise at least one oxide selected from silicon oxides, silicon oxynitrides, silicon oxycarbides and silicon-aluminum mixed oxides. The mixed oxides have the advantage of improving the durability, especially the chemical resistance, compared with pure silicon oxide (SiO ₂ ). The ratio of each of silicon and aluminum does not increase the refractive index of the layer excessively, Can be adjusted accordingly.

The fourth thickness may be suitably selected within the range of 20 to 120 nm, preferably 70 to 110 nm, and more preferably 85 to 95 nm.

It is possible to sufficiently obtain a broadband antireflection effect together with a substantial increase in substrate transmittance not only in the visible light wavelength range but also in a wider infrared region in the structure having the preferable refractive indices and thicknesses of the first, second, third and fourth coating layers described above, Thus, a high performance antireflection multilayer coating can be obtained over a wavelength range from 380 nm to 1,100 nm. However, the present invention is not limited thereto.

On the other hand, the components included in the first coating layer, the second coating layer, the third coating layer and the fourth coating layer are preferably combined as follows.

That is, the inorganic components included in the first coating layer / the second coating layer / the third coating layer / the fourth coating layer are titanium oxynitride / silicon oxide / silicon nitride / silicon oxide and titanium oxynitride / silicon aluminum oxide / silicon aluminum nitride / Silicon aluminum oxide, or a combination thereof.

Here, the silicon aluminum oxide corresponds to an aluminum-silicon mixed oxide. In this case, there is no particular limitation on the ratio of the aluminum to silicon, and for example, the aluminum content in the aluminum-silicon mixed oxide may be appropriately selected within the range of 0.5 to 15 wt% have.

The transparent substrate having the antireflective coating layer exhibits an average transmittance of 92% or more, preferably 93% or more, in the wavelength range of 380 to 1,100 nm, and the transmittance at a wavelength in the range of 380 to 1,100 nm Transmittance is high, and at a wavelength in the range of 1,100 nm to 2,500 nm, the transmittance is lower than that of the substrate before the formation of the multilayer coating.

 5. Manufacturing method of transparent substrate having antireflection coating layer

According to another aspect of the present invention, there is provided a method of manufacturing a multilayer coating transparent substrate, comprising the steps of providing a substrate, forming a first coating layer, forming a second coating layer, forming a third coating layer, and forming a fourth coating layer.

Forming a first coating layer having a refractive index of 2.0 to 2.5 on a transparent substrate and comprising titanium oxynitride; forming a second coating layer having a refractive index of 1.3 to 1.6 on the first coating layer; Forming a third coating layer having a refractive index of 1.9 to 2.3 on the second coating layer, and forming a fourth coating layer having a refractive index of 1.3 to 1.6 on the third coating layer.

There is no particular limitation on the method of sequentially forming the respective coating layers on the transparent substrate, and the physical vapor deposition (PVD), the chemical vapor deposition (CVD), the sol-gel method And a commonly known thin film coating method can be utilized.

Preferably, all the layers can be deposited continuously by the magnetron sputtering method. The sputtering method is particularly suitable for products of large substrates, in which an oxide layer is deposited by reactive sputtering of the metal in the presence of oxygen, and a nitride layer is deposited in the presence of nitrogen. It may also be deposited using a silicon target that is heavily doped with a metal such as aluminum to provide sufficient conductivity to the target in order to form the SiO ₂ or Si ₃ N ₄ layer.

In the case of oxynitride, nitrogen nitride and oxygen gas may be simultaneously supplied into the coating chamber to deposit oxynitride in the presence of nitrogen and oxygen. Specifically, in the case of a TiO.sub.2N thin film, power can be applied to a Ti or TiO.sub.x target in a nitrogen and oxygen atmosphere. At this time, oxygen and nitrogen react with the sputtered target material to form a TiO.sub.2N layer.

TiOaN layer formed by the method by the sputtering efficiency by the plasma relative to the oxide layer of TiO ₂ solid, and the deposition rate can be increased by more than 1.5 times.

6. Solar module

According to another aspect of the present invention, there is provided a solar cell module comprising a transparent substrate for a broadband anti-reflective solar cell of the present invention disposed at an outermost periphery.

The transparent substrate for a broadband antireflective solar cell of the present invention is not particularly limited and may be any of crystalline silicon, amorphous silicon thin film, Dye Sensitized Solar Cell (DSSC), CIGS (CuInGaSe) Type, CdTe type, GaAs type, and III-V group compound semiconductor type.

According to one embodiment of the present invention, the solar cell module to which the transparent substrate for a broadband antireflective solar cell of the present invention is applied exhibits an increase in efficiency of at least 2 to 5% compared to that before application.

Hereinafter, the present invention will be described in more detail by examples and the like. However, the following specific examples are given for the purpose of helping understanding of the present invention, and thus the scope of the present invention is not limited thereto.

[Example]

Layer antireflective coating having the composition shown in Table 1 below was formed on a low iron glass (Table 2) having a thickness of 3.2 mm. Each coating layer was formed using a magnetron sputtering equipment under a deposition condition of a chamber process pressure of 3 to 5 mtorr and a power of 1 kW to 2 kW, and a Ti metal target and a SiAl metal target were used.

The transmittance of the prepared multi-layer coated glass from 380 to 1,100 nm and from 1,100 to 2,500 nm was measured with a spectral transmittance meter (model name: Lambda 950, Perkin Elmer), and the result was found to correspond to AM1.5 according to ISO 9050 The average value obtained by multiplying by the weighting function is shown in Table 3 and FIG.

[Comparative Example]

The transmittance of 380-1100nm and 1,100-2,500nm was measured on a 3.2mm thick low iron substrate glass used in the examples (i.e., without an antireflective multilayer coating), as used in the examples, using a spectral transmittance meter (Model Lambda 950, Perkin Elmer), and the results are shown in Table 3 and FIG. 2, which are obtained by multiplying the result by the weighted coefficient corresponding to AM1.5 according to the ISO 9050 standard. The comparative example was used as a reference for comparing the transmittance improvement rate of the antireflection coating layer.

The coating film (from the substrate) Refractive index Film thickness (nm) TiO _{0 .3} N _{0 .7} (first layer) 2.25 10 Si _{0 .92} Al _{0 .08} O ₂ (second layer) 1.47 35 Si ₃ N ₄ (third layer) 1.99 155 Si _{0 .92} Al _{0 .08} O ₂ (fourth layer) 1.48 90

※ Refractive index value is based on @ 550nm

division Refractive index Substrate thickness (mm) Substrate glass 1.51 3.2

※ Refractive index value is based on @ 550nm

division Transmittance (380 to 1,100 nm) Transmittance (1,100 to 2,500 nm) Example 94.05% 83.98% Comparative Example 91.97% 91.87%

The scope of the present invention is defined by the following claims, and is not limited to the description of the specification, and all variations and modifications falling within the scope of the claims are included in the scope of the present invention.

Claims (11)

Transparent substrate;
A first coating layer formed on the transparent substrate at a first refractive index, the first coating layer comprising titanium oxynitride;
A second coating layer formed on the first coating layer at a second refractive index;
A third coating layer formed on the second coating layer at a third refractive index; And
And a fourth coating layer formed on the third coating layer at a fourth refractive index,
Wherein the first refractive index is greater than the second refractive index and the third refractive index is greater than the fourth refractive index. The method according to claim 1,
Wherein the first refractive index is 2.0 to 2.5, the second refractive index is 1.3 to 1.6, the third refractive index is 1.9 to 2.3, and the fourth refractive index is 1.3 to 1.6. The method according to claim 1,
Wherein the first coating layer has a thickness of 5 to 30 nm, the second coating layer has a thickness of 20 to 50 nm, the third coating layer has a thickness of 100 to 180 nm, and the fourth coating layer has a thickness of 70 to 110 nm. The method according to claim 1,
Wherein the third coating layer has an antireflective coating layer comprising at least one nitride selected from silicon nitride, silicon aluminum nitride. The method according to claim 1,
Wherein the second coating layer and the fourth coating layer have an antireflection coating layer comprising at least one material selected from silicon oxide, silicon oxynitride, silicon oxycarbide, and silicon-aluminum mixed oxide. The method according to claim 1,
Wherein the transparent substrate has an antireflection coating layer exhibiting an average transmittance of 92% or more in a wavelength range of 380 to 1,100 nm. The method according to claim 1,
The transparent substrate has a higher transmittance than that of the transparent substrate before forming the first, second, third and fourth coating layers in the wavelength range of 380 to 1,100 nm, and the first, second, third, 4 A transparent substrate having an antireflection coating layer having a lower transmittance than a transparent substrate before forming a coating layer. (1) forming a first coating layer having a refractive index of 2.0 to 2.5 on a transparent substrate and comprising titanium oxynitride;
(2) forming a second coating layer having a refractive index of 1.3 to 1.6 on the first coating layer;
(3) forming a third coating layer having a refractive index of 1.9 to 2.3 on the second coating layer; And
(4) forming a fourth coating layer having a refractive index of 1.3 to 1.6 on the third coating layer. 9. The method of claim 8,
And an anti-reflection coating layer continuously forming the coating layers by a magnetron sputtering method. A solar cell module comprising the transparent substrate according to any one of claims 1 to 7. 11. The method of claim 10,
Wherein the solar cell is one solar cell selected from the group consisting of crystalline silicon, amorphous silicon thin film, dye sensitized, CIGS (CuInGaSe) type, CdTe type, GaAs type or III-V compound semiconductor type.

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