KR102767707B1 - Glass frit composition for forming solar cell electrode, solar cell electrode formed by using the same glass composition, and solar cell including the same electrode - Google Patents

Abstract

A glass frit composition for forming a solar cell electrode, an electrode for a solar cell formed using the same, and a solar cell including the electrode, the glass frit is a lead (Pb)-silicon (Si)-zinc (Zn)-based glass frit, and comprises 51.0 to 60.0 mol% of lead oxide (PbO) as a first metal oxide, 8.0 to 19.0 mol% of silicon oxide (SiO ₂ ) as a second metal oxide, 5.0 to 20.0 mol% of zinc oxide (ZnO) as a third metal oxide, 5.0 to 20.0 mol% of boron oxide (B ₂ O ₃ ) as a fourth metal oxide, and the remainder of aluminum oxide (Al ₂ O ₃ ) as a fifth metal oxide, based on the total amount of the glass frit (100 mol%), and satisfies the following Formula 1.
<Formula 1>
65.5 ≤ [PbO] + [ZnO] + [Al ₂ O ₃ ] ≤ 73.4
([PbO], [ZnO], and [Al ₂ O ₃ ] in the above formula 1 represent the mol% of PbO, ZnO, and Al ₂ O _{3 ,} respectively.)

Description

Glass frit composition for forming solar cell electrode, solar cell electrode formed using the same, and solar cell including the same electrode {GLASS FRIT COMPOSITION FOR FORMING SOLAR CELL ELECTRODE, SOLAR CELL ELECTRODE FORMED BY USING THE SAME GLASS COMPOSITION, AND SOLAR CELL INCLUDING THE SAME ELECTRODE}

The present invention relates to a battery, and more particularly, to a glass frit composition for forming a solar cell electrode, an electrode for a solar cell formed using the same, and a solar cell including the electrode.

Due to concerns about environmental pollution caused by fossil fuels and the depletion of said fossil fuels, research is being actively conducted to develop next-generation clean energy. Among the next-generation clean energies, solar energy in particular is abundant in resources and does not emit pollutants during the energy production process, so much research is being conducted as an energy source to replace fossil fuels.

The solar cell utilizing the solar energy mentioned above is a photoelectric conversion element that converts the solar energy into electrical energy, and is receiving attention as an infinite, pollution-free next-generation energy resource. In order to increase the efficiency of such solar cells, it is important to be able to output as much electrical energy as possible from solar energy, and one way to do this is to make it large-area.

However, as the solar cell area increases, the line resistance and contact resistance between the semiconductor substrate and the electrode increase, which may lead to a problem of decreasing the efficiency of the cell.

The technical problem to be solved by the present invention is to provide a glass frit composition for forming a solar cell electrode that ensures thermal stability while minimizing line resistance and contact resistance by improving the contact between a semiconductor substrate and an electrode.

In addition, another technical problem to be solved by the present invention is to provide an electrode for a solar cell formed using a glass frit composition for forming a solar cell electrode having the above advantages.

In addition, another technical problem to be solved by the present invention is to provide a solar cell including a solar cell electrode having the above advantages.

Glass frit composition for forming electrodes of solar cells

In one embodiment of the present invention, a glass frit composition for forming an electrode of a solar cell, which is a lead (Pb)-silicon (Si)-zinc (Zn)-based glass frit, is provided. Specifically, the glass frit composition for forming an electrode of a solar cell contains 51.0 to 60.0 mol% of lead oxide (PbO) as a first metal oxide, 8.0 to 19.0 mol% of silicon oxide (SiO ₂ ) as a second metal oxide, 5.0 to 15.0 mol% of zinc oxide (ZnO) as a third metal oxide, 5.0 to 20.0 mol% of boron oxide (B ₂ O ₃ ) as a fourth metal oxide, and the remainder of aluminum oxide (Al ₂ O ₃ ) as a fifth metal oxide, with respect to the total amount of glass frit (100 mol%), and can satisfy the following Equation 1.

<Formula 1>

65.5 ≤ [PbO] + [ZnO] + [Al ₂ O ₃ ] ≤ 73.4

([PbO], [ZnO], and [Al ₂ O ₃ ] in the above formula 1 represent the mol% of PbO, ZnO, and Al ₂ O _{3 ,} respectively.)

In one embodiment, the glass frit composition may include 0.5 to 5.0 mol % of the sixth metal oxide, gallium oxide (Ga ₂ O ₃ ), based on the total amount (100 mol %) of the glass frit. In one embodiment, the glass frit composition may include 0.5 to 5.0 mol % of the seventh metal oxide, yttrium oxide (Y ₂ O ₃ ), based on the total amount (100 mol %) of the glass frit. In one embodiment, the glass frit composition may include 0.5 to 6.0 mol % of the eighth metal oxide, silver oxide (Ag ₂ O ), based on the total amount (100 mol %) of the glass frit.

In one embodiment, the glass frit composition for forming an electrode of a solar cell can satisfy the following formula 2.

<Formula 2>

0.60 ≤ [PbO]/([ZnO]×[Al ₂ O ₃ ]+[Ag ₂ O]) ≤ 14.0

(In the above formula 2, [PbO], [ZnO], [Al ₂ O ₃ ], and [Ag ₂ O] represent the mole (mol%) of PbO, ZnO, Al ₂ O ₃ , and Ag ₂ O, respectively.)

In one embodiment, the glass frit composition can include 51.0 to 56.3 mol % of the first metal oxide, lead oxide (PbO), with respect to the glass frit composition (100 mol %). In one embodiment, the glass frit composition can include 1.0 to 5.0 mol % of the fifth metal oxide, aluminum oxide (Al ₂ O ₃ ), with respect to the glass frit composition (100 mol %).

In one embodiment, the line resistivity of the glass frit may be less than 3.0 uΩㆍcm (except 0 uΩㆍcm). In one embodiment, the contact resistivity of the glass frit may be less than 2.0 mΩㆍcm2 (except 0 mΩㆍcm2). In one embodiment, the adhesion of the glass frit may be greater than 2.0 N.

Paste composition for forming electrodes of solar cells

In another embodiment of the present invention, a paste composition for forming an electrode of a solar cell includes a conductive powder, a glass frit, and an organic vehicle; wherein the glass frit is a lead (Pb)-silicon (Si)-zinc (Zn)-based glass frit, and with respect to the total amount (100 mol%) of the glass frit, a first metal oxide, lead oxide (PbO), is contained in an amount of 51.0 to 60.0 mol%, a second metal oxide, silicon oxide (SiO ₂ ), is contained in an amount of 8.0 to 19.0 mol%, a third metal oxide, zinc oxide (ZnO), is contained in an amount of 5.0 to 20.0 mol%, a fourth metal oxide, boron oxide (B ₂ O ₃ ), is contained in an amount of 5.0 to 20.0 mol%, and a remainder of a fifth metal oxide, aluminum oxide (Al ₂ O ₃ ), is contained, and is represented by the following formula 1: Can be satisfied.

<Formula 1>

65.5 ≤ [PbO] + [ZnO] + [Al ₂ O ₃ ] ≤ 73.4

([PbO], [ZnO], and [Al ₂ O ₃ ] in the above formula 1 represent the mol% of PbO, ZnO, and Al ₂ O _{3 ,} respectively.)

In one embodiment, the seventh metal oxide, aluminum oxide (Al ₂ O ₃ ), may be included in an amount of 1.0 to 5.0 mol% with respect to the total amount of the glass frit (100 mol%). In one embodiment, the eighth metal oxide, silver oxide (Ag ₂ O ), may be included in an amount of 0.5 to 6.0 mol% with respect to the total amount of the glass frit (100 mol%).

In one embodiment, a paste composition for forming an electrode of a solar cell may satisfy the following equation 2.

<Formula 2>

0.60 ≤ [PbO]/([ZnO]×[Al ₂ O ₃ ]+[Ag ₂ O]) ≤ 14.0

(In the above formula 2, [PbO], [ZnO], [Al ₂ O ₃ ], and [Ag ₂ O] represent the mole (mol%) of PbO, ZnO, Al ₂ O ₃ , and Ag ₂ O, respectively.)

In one embodiment, the fifth metal oxide, aluminum oxide (Al ₂ O ₃ ), may be included in an amount of 1.0 to 5.0 mol% with respect to the total amount of the glass frit (100 mol%). In one embodiment, the conductive powder may include at least one conductive powder selected from the group consisting of silver (Ag) powder, silver (Ag)-containing alloy powder, aluminum (Al) powder, aluminum (Al)-containing alloy powder, copper (Cu) powder, aluminum (Al)-containing alloy powder, nickel (Ni) powder, and nickel (Ni)-containing alloy powder.

In one embodiment, the organic vehicle may include an organic binder and an organic solvent. In one embodiment, the paste composition for forming an electrode of a solar cell may further include an additive. In one embodiment, with respect to the total amount of the paste composition (100 wt%), the conductive powder may be included in an amount of 86 to 90 wt%, the glass frit may be included in an amount of 2.0 to 6.0 wt%, the organic vehicle may be included in an amount of 7 to 12.5 wt%, and the remainder may include aluminum powder.

Electrodes of a solar cell

In another embodiment of the present invention, an electrode for a solar cell is provided, manufactured using the glass frit composition described above.

Independently, in another embodiment of the present invention, an electrode for forming an electrode of a solar cell manufactured using the above-described paste composition is provided.

solar cell

In another embodiment of the present invention, a solar cell can be provided, comprising: a semiconductor substrate; and an electrode positioned on at least one surface of the semiconductor substrate and formed using the glass frit composition described above.

Independently, in another embodiment of the present invention, a solar cell can be provided, comprising an electrode positioned on at least one surface of the semiconductor substrate and formed using the paste composition described above.

A glass frit composition for forming a solar cell electrode according to one embodiment of the present invention simultaneously contains lead oxide (PbO), zinc oxide (ZnO), and aluminum oxide (Al ₂ O ₃ ) with respect to the total amount of glass frit (100 mol%), and by controlling the composition in the glass frit composition, a glass frit composition can be provided that reduces the contact resistance between the electrode and the semiconductor substrate, ensures thermal stability, and has excellent adhesive strength.

A paste composition for forming a solar cell electrode according to one embodiment of the present invention can provide a paste composition for forming a solar cell electrode that lowers contact resistance during electrode formation, ensures thermal stability, and has excellent adhesive strength by using a glass frit composition for forming a solar cell electrode having the advantages described above.

According to one embodiment of the present invention, a solar cell electrode can provide a solar cell electrode having low contact resistance, secured thermal stability, and excellent adhesive strength by using a glass frit composition for forming a solar cell electrode or a paste composition for forming a solar cell electrode having the advantages described above.

According to another embodiment of the present invention, a solar cell can improve the efficiency and thermal stability of the solar cell by using the electrode of the solar cell having the advantages described above.

FIG. 1 is a schematic diagram of a solar cell according to one embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail. However, these are presented as examples, and the present invention is not limited thereby, and the present invention is defined only by the scope of the claims described below.

In order to clearly express various layers and regions in the drawings, the thickness is enlarged and shown. Similar parts are designated by the same drawing reference numerals throughout the specification. When a part such as a layer, film, region, or plate is said to be "on" another part, this includes not only the case where it is "directly on" the other part, but also the case where there is another part in between. Conversely, when a part is said to be "directly on" another part, it means that there is no other part in between.

In general, the electrode of a solar cell can be formed by a series of processes including mixing a conductive powder, glass frit, and an organic vehicle, adding additional additives as needed to prepare a paste composition, applying the paste composition to one or both sides of a semiconductor substrate, patterning the composition, and then firing and drying the applied paste composition. Considering this electrode formation process, it can be seen that lowering the line resistance and contact resistance by improving the contactability between the semiconductor substrate and the electrode formed thereon is an important factor in increasing the efficiency of the solar cell.

Specifically, the glass frit etches an antireflection film during the firing process and melts a conductive powder to generate metal crystal particles in the emitter region, thereby improving the adhesion between the electrode (particularly, the metal crystal particles) and the semiconductor substrate, thereby lowering line resistance and contact resistance, and also inducing the effect of lowering the firing temperature by softening.

In this regard, in one embodiment of the present invention, a glass frit having secured thermal stability while lowering the contact resistance between an electrode and a semiconductor substrate is commonly applied to improve the efficiency and thermal stability of a solar cell.

Glass frit composition for forming electrodes of solar cells

In one embodiment of the present invention, a glass frit composition for forming an electrode of a solar cell is provided, which is a lead (Pb)-silicon (Si)-zinc (Zn)-based glass frit. Specifically, the glass frit composition is a glass frit containing lead oxide (PbO), silicon oxide (SiO ₂ ), zinc oxide (ZnO), boron oxide (B ₂ O ₃ ), and aluminum oxide (Al ₂ O ₃ ) as main components.

More specifically, the glass frit composition may include, based on the total amount of the glass frit (100 mol%), a first metal oxide such as lead oxide (PbO), a second metal oxide such as silicon oxide (SiO ₂ ), a third metal oxide such as zinc oxide (ZnO), a fourth metal oxide such as boron oxide (B ₂ O ₃ ), and a remainder such as a fifth metal oxide such as aluminum oxide (Al ₂ O ₃ ).

Specifically, with respect to the total amount of the glass frit (100 mol%), the first metal oxide, lead oxide (PbO), may be included in an amount of 51.0 to 60.0 mol%, the second metal oxide, silicon oxide (SiO ₂ ), may be included in an amount of 8.0 to 19.0 mol%, the third metal oxide, zinc oxide (ZnO), may be included in an amount of 5.0 to 15.0 mol%, the fourth metal oxide, boron oxide (B ₂ O ₃ ), may be included in an amount of 5.0 to 20.0 mol%, and the remainder may be aluminum oxide (Al ₂ O ₃ ) as the fifth metal oxide. The above glass frit composition is a lead (Pb)-silicon (Si)-zinc (Zn)-based glass frit containing lead oxide (PbO), silicon oxide (SiO ₂ ), zinc oxide (ZnO), and boron oxide (B ₂ O ₃ ) as main components.

Specifically, the first metal oxide, lead oxide (PbO), may be included in an amount of 51.0 to 60.0 mol% with respect to the total amount of the glass frit (100 mol%). Specifically, the first metal oxide may be included in an amount of 51.0 to 56.4 mol%, and more specifically, in an amount of 51.2 to 56.2 mol%.

The above first metal oxide has a problem of adhesion when the upper limit of the above range is exceeded. The above first metal oxide has a problem of high line resistance when the lower limit of the above range is exceeded.

The second metal oxide, silicon oxide (SiO ₂ ), may be included in an amount of 8.0 to 19.0 mol% with respect to the total amount of the glass frit (100 mol%). Specifically, the second metal oxide may be included in an amount of 10.0 to 15.0 mol%, and more specifically, in an amount of 12.2 to 14.9 mol%.

The above second metal oxide has a problem that the line resistivity and contact resistivity become excessively high when the upper limit of the above range is exceeded. The above second metal oxide has a problem that the adhesive strength decreases when the lower limit of the above range is exceeded.

The third metal oxide, zinc oxide (ZnO), may be included in an amount of 5.0 to 15.0 mol% with respect to the total amount of the glass frit (100 mol%). Specifically, the third metal oxide may be included in an amount of 5 to 13 mol%, more specifically, 5 to 12.9 mol%, and even more specifically, 10.8 to 12.9 mol%.

The above third metal oxide has a problem that the line resistance and contact resistance increase when the upper limit of the above range is exceeded. The above third metal oxide has a problem that the adhesive strength decreases when the lower limit of the above range is exceeded.

The fourth metal oxide, boron oxide (B ₂ O ₃ ), may be included in an amount of 5.0 to 20.0 mol% with respect to the total amount of the glass frit (100 mol%). Specifically, the fourth metal oxide may be included in an amount of 5.0 to 15.0 mol%, and more specifically, in an amount of 9.4 to 11.4 mol%.

The fourth metal oxide has a problem that the line resistance increases and the adhesive strength decreases when the upper limit of the above range is exceeded. Specifically, the fourth metal oxide has a problem that the contact resistance increases when the lower limit of the above range is exceeded.

The fifth metal oxide may be included as a remainder with respect to the total amount of the glass frit (100 mol%). Specifically, the fifth metal oxide, aluminum oxide (Al ₂ O ₃ ), may be included in an amount of 1.0 to 5.0 mol%. Specifically, the fifth metal oxide may be included in an amount of 1.0 to 4.0 mol%, and more specifically, in an amount of 3.8 to 4.0 mol%.

If the content of the fifth metal oxide exceeds the upper limit of the above range, there is a problem that the line resistance increases. Specifically, if the content of the fifth metal oxide exceeds the lower limit of the above range, there is a problem that the adhesive strength decreases.

A lead (Pb)-silicon (Si)-zinc (Zn)-based glass frit containing the first to fifth metal oxides as essential components and having a content satisfying the content ranges described above lowers line resistance and contact resistance between an electrode and a semiconductor substrate, while ensuring thermal stability; and this fact is supported by the examples and evaluation examples described below.

In one embodiment, the glass frit composition may further comprise at least one of the sixth to eighth metal oxides relative to the total amount (100 mol %) of the glass frit. The glass frit composition essentially comprises the first to fifth metal oxides, and may further comprise at least one of the sixth to eighth metal oxides.

In one embodiment, the glass frit composition for forming an electrode of a solar cell may include a sixth metal oxide. The sixth metal oxide is gallium oxide (Ga ₂ O ₃ ). The sixth metal oxide may be included in an amount of 0.5 to 5.0 mol% of gallium oxide (Ga ₂ O ₃ ) based on the total amount of the glass frit (100 mol%). Specifically, the sixth metal oxide may be included in an amount of 2.0 to 4.0 mol%, more specifically, 3.0 to 4.0, and even more specifically, 3.3 to 3.5 mol%.

When the above sixth metal oxide exceeds the upper limit of the above-mentioned range, there is a problem that the contact resistance increases. When the above sixth metal oxide exceeds the lower limit of the above-mentioned range, there is a problem that the contact resistance increases.

In one embodiment, the glass frit composition for forming an electrode of a solar cell may include a seventh metal oxide. The seventh metal oxide is yttrium oxide (Y ₂ O ₃ ). The seventh metal oxide may include 0.5 to 5.0 mol% of yttrium oxide (Y ₂ O ₃ ) based on the total amount of the glass frit (100 mol%). Specifically, the seventh metal oxide may be included in an amount of 2.0 to 4.0 mol%, more specifically, 3.0 to 4.0, and even more specifically, 3.3 to 3.5 mol%.

The seventh metal oxide has a problem in that the adhesive strength decreases when the value exceeds the upper limit of the above range. The seventh metal oxide has a problem in that the contact resistance increases when the value exceeds the lower limit of the above range.

In one embodiment, the glass frit composition for forming an electrode of a solar cell may include an eighth metal oxide. The eighth metal oxide is silver oxide (Ag ₂ O). The eighth metal oxide may include 0.5 to 6.0 mol% of silver oxide (Ag ₂ O) with respect to the total amount of the glass frit (100 mol%). Specifically, the eighth metal oxide may be included in an amount of 4.0 to 5.5 mol%.

The above eighth metal oxide has a problem that the contact resistance increases and the adhesive strength decreases when the upper limit of the above range is exceeded. The above eighth metal oxide has a problem that the contact resistance increases when the lower limit of the above range is exceeded.

In one embodiment, the glass frit composition for forming the electrode of the solar cell may satisfy the following formula 1.

<Formula 1>

65.5 ≤ [PbO] + [ZnO] + [Al ₂ O ₃ ] ≤ 73.4

([PbO], [ZnO], and [Al ₂ O ₃ ] in the above formula 1 represent the mol% of PbO, ZnO, and Al ₂ O _{3 ,} respectively.)

The above formula 1 means that PbO, ZnO, and Al ₂ O ₃ are simultaneously included, and the molar contents of the first metal oxide, the third metal oxide, and the fifth metal oxide can satisfy the above-mentioned range. By satisfying the above formula 1, high adhesive strength and low line resistance can be secured.

By satisfying the above range of the above formula 1, both the line resistance and the contact resistance are appropriately controlled, so that a solar cell having improved efficiency can be obtained. If the value of the above formula 1 is outside the upper limit of the above range, there is a problem that the line resistance increases. There is a problem that the line resistance increases. If the value of the above formula 1 is outside the lower limit of the above range, there is a problem that the contact resistance increases.

In one embodiment, the glass frit composition for forming an electrode of a solar cell can satisfy the following formula 2.

<Formula 2>

0.60 ≤ [PbO]/([ZnO]×[Al ₂ O ₃ ]+[Ag ₂ O]) ≤ 14.0

(In the above formula 2, [PbO], [ZnO], [Al ₂ O ₃ ], and [Ag ₂ O] represent the mole (mol%) of PbO, ZnO, Al ₂ O ₃ , and Ag ₂ O, respectively.)

The above equation 2 is about the molar content of the first metal oxide with respect to the sum of the molar contents of the second metal oxide, the fifth metal oxide, and the eighth metal oxide, and is an indicator of the suitability of the line resistance and the contact resistance.

By satisfying the above range of the above equation 2, both the line resistance and the contact resistance are appropriately controlled, so that a solar cell with improved efficiency can be obtained. If the value of the above equation 2 is outside the upper limit of the above range, there is a problem that the line resistance increases. There is a problem that the line resistance increases. If the value of the above equation 2 is outside the lower limit of the above range, there is a problem that the contact resistance increases.

The above glass frit can lower line resistance and contact resistance by improving adhesion between the electrode and the semiconductor substrate, and can satisfy each range of adhesion, line resistance, and contact resistance described below.

In one embodiment, the adhesion of the glass frit may be greater than 2.0 N. In one embodiment, the line resistance of the glass frit may be less than 3.0 uΩㆍcm (excluding 0 uΩㆍcm). In one embodiment, the contact resistance of the glass frit may be less than 2.0 mΩㆍcm2 (excluding 0 mΩㆍcm2).

The above glass frit can contribute to lowering the sintering temperature by softening at an appropriate softening point, and can satisfy each range of the glass transition temperature (T _g ) and the highest peak temperature (T _p ) described below. In one embodiment, the glass transition temperature (T _g ) of the glass frit can satisfy a temperature range of 330 to 400 ° C. In one embodiment, the highest peak temperature (T _p ) of the glass frit can satisfy a temperature range of 500 to 560 ° C.

The above glass frit can be manufactured using a conventional method. For example, the glass frit contains lead oxide (PbO), gallium oxide (Ga ₂ O ₃ ), yttrium oxide (Y ₂ O ₃ ), silicon oxide (SiO ₂ ), zinc oxide (ZnO), and boron oxide (B ₂ O ₃ ) as main components, and the remainder includes glass frit raw materials different from the above main components, and each component is mixed so that each component satisfies a specific content range. The mixing at this time can be performed by a physical or chemical method, and as a non-limiting example, can be performed using a ball mill, a planetary mill, etc.

Thereafter, the mixed composition is melted at a temperature range of 900°C to 1,300°C, quenched at room temperature (25°C), and then pulverized using a disk mill, a planetary mill, or the like, thereby finally obtaining a glass frit having an adjusted particle size. Specifically, the finally obtained glass frit may have a D50 particle size of 0.1 to 10 μm, and its shape may be, as a non-limiting example, spherical or amorphous.

Paste composition for forming electrodes of solar cells

In another embodiment of the present invention, a paste composition for forming an electrode of a solar cell includes a conductive powder; a glass frit; and an organic vehicle; wherein the glass frit may be a lead (Pb)-silicon (Si)-zinc (Zn) based glass frit. The paste composition may include 51.0 to 60.0 mol% of a first metal oxide, lead oxide (PbO), 8.0 to 19.0 mol% of a second metal oxide, silicon oxide (SiO ₂ ), 5.0 to 15.0 mol% of a third metal oxide, zinc oxide (ZnO), 5.0 to 20.0 mol% of a fourth metal oxide, boron oxide (B ₂ O ₃ ), and the remainder of a fifth metal oxide, aluminum oxide (Al ₂ O ₃ ). The above glass frit composition is a lead (Pb)-silicon (Si)-zinc (Zn)-based glass frit containing lead oxide (PbO), silicon oxide (SiO ₂ ), zinc oxide (ZnO), and boron oxide (B ₂ O ₃ ) as main components. Specifically, the paste composition is a paste composition that uses the above-described glass frit and mixes it with a conductive powder and an organic vehicle.

The glass frit may be included in an amount of 1.0 to 6.0 wt%, specifically 2.0 to 6.0 wt%, based on the total amount (100 wt%) of the paste composition. When the glass frit is included within the above content range, the adhesion between the electrode and the semiconductor substrate is improved, thereby enabling a solar cell with excellent efficiency to be implemented. Hereinafter, redundant descriptions of the glass frit will be omitted, and the remaining components of the paste composition will be described in detail.

The conductive powder is not particularly limited as long as it is a conductive powder that has conductivity and can perform the function of collecting photogenerated charges, and as a non-limiting example, it may include at least one or more conductive powders selected from the group including silver (Ag) powder, silver (Ag)-containing alloy powder, aluminum (Al) powder, aluminum (Al)-containing alloy powder, copper (Cu) powder, aluminum (Al)-containing alloy powder, nickel (Ni) powder, and nickel (Ni)-containing alloy powder. However, it is not limited thereto and may be another type of metal powder and may include other additives in addition to the metal powder.

In one embodiment, the conductive powder may be an aggregate of conductive particles having different particle sizes, and the average particle size may be 0.001 to 50 μm. In one embodiment, when the conductive powder is silver (Ag) powder, it may have an average particle size of 0.001 to 10 μm. At this time, the shape of the conductive particles may be any shape among spherical, plate-shaped, and amorphous, as a non-limiting example.

The above-mentioned conductive powder may be included in an amount of 80 to 95 wt%, and specifically, 86 to 90 wt%, based on the total amount (100 wt%) of the paste composition.

When the conductive powder is included within the above content range, excellent electrical conductivity can be achieved by an appropriate filling density of the conductive powder during firing, and excellent dispersibility can be achieved when producing a paste composition. The organic vehicle is mixed with the conductive powder to provide an appropriate viscosity to form a paste, and may include an organic binder and an organic solvent that dissolves the same.

The above organic binder is a non-limiting example, and may be used alone or in combination of two or more types including ethyl cellulose, ethyl hydroxyethyl cellulose, nitro cellulose, and acrylic acid ester resin.

The organic solvent mentioned above is a non-limiting example, and includes a glycol ether solvent such as 2,2,4-trimethyl-monoisobutyrate (Texanol), butyl carbitol acetate (diethylene glycol monobutyl ether acetate), toluene, ethyl cellosolve, butyl celosolve, butyl carbitol (diethylene glycol monobutyl ether), dibutyl carbitol (diethylene glycol dibutyl ether), propylene glycol monomethyl ether, hexylene glycol, terpineol, methyl ethyl ketone, 3-pentanediol, etc., which may be used alone or in combination of two or more solvents.

With respect to the total amount (100 wt%) of the paste composition, the organic vehicle may be included in an amount of 5 to 40 wt%, specifically 7.0 to 12.5 wt%. When the organic vehicle is included within the above content range, a paste composition having an appropriate viscosity can be prepared.

Considering the specific content range of each component described above, the conductive powder may be included in an amount of 86 to 90 wt%, the glass frit may be included in an amount of 2.0 to 6.0 wt%, the organic vehicle may be included in an amount of 7 to 12.5 wt%, and the remainder may be aluminum powder, with respect to the total amount of the paste composition (100 wt%).

In one embodiment, the aluminum powder may include 0.5 to 2.0 wt%. In one embodiment, by including the aluminum powder in the above-described range, there is an advantage of reducing contact resistance.

In one embodiment, the average particle diameter of the aluminum powder may be in the range of 2.0 to 3.0 μm, specifically, 2.5 to 3.0 μm. If the average particle diameter exceeds the upper limit, there is a problem of increased contact resistance. If the average particle diameter exceeds the lower limit, there is a problem of explosion and fire due to the reaction of Al.

In one embodiment, the paste composition may further include an additive. The additive may be a dispersant, a thixotropic agent, a plasticizer, a viscosity stabilizer, an antifoaming agent, an ultraviolet stabilizer, an antioxidant, a coupling agent, etc., used alone or in combination of two or more, as needed. In one embodiment, the additive may be included in an amount of 0.1 to 5 wt% with respect to the total amount of the paste composition (100 wt%).

Electrodes of a solar cell

In another embodiment of the present invention, an electrode for a solar cell is provided, which is manufactured using the aforementioned glass frit composition or a paste composition containing the same. The electrode may be a front electrode or a rear electrode, and is manufactured using the aforementioned glass frit composition or a paste composition containing the same, thereby improving the efficiency of the solar cell while ensuring thermal stability.

Duplicate descriptions of the aforementioned glass frit composition or paste composition containing the same will be omitted, and the electrode and its forming method will be described below.

solar cell

In another embodiment of the present invention, a solar cell is provided, comprising: a semiconductor substrate; and an electrode positioned on at least one surface of the semiconductor substrate and formed using the glass frit composition described above or a paste composition including the same.

Figure 1 illustrates a cross-sectional view of the solar cell.

Hereinafter, a solar cell according to an embodiment will be described with reference to Fig. 1. This is a non-limiting example, and the solar cell is not limited to Fig. 1.

Hereinafter, for convenience of explanation, the upper and lower positional relationship will be described with the semiconductor substrate (10) as the center, but it is not limited thereto. In addition, the side of the semiconductor substrate (10) that receives solar energy is called the front side, and the side opposite to the front side is called the rear side.

Referring to FIG. 1, a solar cell according to one embodiment includes a semiconductor substrate (10) including a lower semiconductor layer (10a) and an upper semiconductor layer (10b).

The above semiconductor substrate (10) can be made of a semiconductor material. The semiconductor material can be specifically crystalline silicon or a compound semiconductor, and a silicon wafer can be used as the crystalline silicon.

One of the lower semiconductor layer (10a) and the upper semiconductor layer (10b) may be a semiconductor layer doped with a p-type impurity, and the other may be a semiconductor layer doped with an n-type impurity. For example, the lower semiconductor layer (10a) may be a semiconductor layer doped with the p-type impurity, and the upper semiconductor layer (10b) may be a semiconductor layer doped with the n-type impurity. The p-type impurity may be a group III compound such as boron (B), and the n-type impurity may be a group V compound such as phosphorus (P).

In one embodiment, an electrode is formed on at least one surface of the semiconductor substrate (10). The electrode may include a front electrode (20) and a rear electrode (30), but this is a non-limiting example and is not limited to the above structure.

In one embodiment, an anti-reflection film (12) may be formed on the front surface of the semiconductor substrate (10). The anti-reflection film (12) may be formed on the front surface of the semiconductor substrate (10) that receives solar energy to reduce the reflectivity of light and increase the selectivity of a specific wavelength region. In addition, the contact characteristics with silicon present on the surface of the semiconductor substrate (10) may be improved to increase the efficiency of the solar cell.

The above anti-reflection film (12) can be made of a material that absorbs little light and has insulating properties. The anti-reflection film can be, as non-limiting examples, silicon nitride (SiN _x ), silicon oxide (SiO ₂ ), titanium oxide (TiO ₂ ), aluminum oxide (Al ₂ O ₃ ), magnesium oxide (MgO), cerium oxide (CeO ₂ ), and combinations thereof, and can be formed as a single layer or multiple layers. In one embodiment, the anti-reflection film (12) can have a thickness of 200 to 1500 Å, but is not limited thereto.

A plurality of front electrodes (20) may be formed on the anti-reflection film (12). The front electrodes (20) may extend in parallel along one direction of the semiconductor substrate (10), but are not limited thereto.

The above front electrode (20) can be formed using the above-described glass frit composition or a paste composition containing the same, and can be formed by a screen printing method. The conductive powder included in the composition at this time can be a low-resistance conductive powder such as silver (Ag).

A bus bar electrode (not shown) may be formed on the front electrode (21). The bus bar electrode is for connecting neighboring solar cells when assembling a plurality of solar cells.

A rear electrode (30) may be formed on the lower portion of the semiconductor substrate (10). The rear electrode (30) may be formed by a screen printing method using the aforementioned glass frit composition or a paste composition containing the same. The conductive powder included in the paste composition may use an opaque metal such as aluminum (Al).

In one embodiment, the solar cell may include the steps of preparing a semiconductor substrate (10), doping the semiconductor substrate (10) with an n-type impurity, forming a front electrode (20), and forming a back electrode (30).

The step of preparing a semiconductor substrate (10) is a step of preparing a semiconductor substrate (10) for solar cell manufacturing. As the semiconductor substrate (10), a silicon wafer can be used, and this can be doped with a p-type impurity.

The step of doping an n-type impurity into a semiconductor substrate (10) is a step of doping an n-type impurity onto a semiconductor substrate (10). The n-type impurity can be doped by diffusing POCl ₃ , H ₃ PO ₄ , or the like at a high temperature. Accordingly, the semiconductor substrate (10) can include a lower semiconductor layer (10a) and an upper semiconductor layer (10b) doped with different impurities.

The step of forming the front electrode (20) is a step of forming an electrode that comes into contact with the upper semiconductor layer (10). An anti-reflection film (12) can be formed on the upper semiconductor layer (10b). The glass frit composition described above or a paste composition containing the same can be applied on the anti-reflection film (12) and then dried to form the front electrode (20). At this time, as the glass frit in the composition melts and penetrates the anti-reflection film (12), the front electrode (20) comes into contact with the upper semiconductor layer (10b).

The step of forming the rear electrode (30) can be performed by applying the aforementioned glass frit composition or a paste composition containing the same on the lower semiconductor layer (10a) and then drying it to form the rear electrode (30).

In one embodiment, when forming the front electrode (20) and the rear electrode (30), each composition may be applied by a screen printing method, and then fired and dried. The firing may be performed in a firing furnace, and the temperature may be raised to a temperature higher than the melting temperature of the conductive powder in each composition. The firing may be performed, for example, in a temperature range of about 700 to 900° C. A solar cell having the above structure may be manufactured according to the above steps, but is not limited thereto.

Hereinafter, preferred embodiments of the present invention, comparative examples thereof, and evaluation examples comparing and evaluating them are described. However, the following examples are only some of the preferred embodiments of the present invention, and the present invention is not limited to the following examples.

Examples 1 to 18

(1) Manufacturing of glass frit

To satisfy Table 1 below, lead oxide (PbO), silicon oxide (SiO ₂ ), zinc oxide (ZnO), boron oxide (B ₂ O ₃ ), aluminum oxide (Al ₂ O ₃ ), gallium oxide (Ga ₂ O ₃ ), yttrium oxide (Y ₂ O ₃ ), and silver oxide (Ag ₂ O) were mixed to prepare glass frit compositions of Examples 1 to 9, respectively.

The mixing at this time was performed for a sufficient amount of time using a zero-gravity mixer to ensure that all components in the glass frit composition were completely mixed. The mixed glass composition was then placed in a platinum crucible, and melting was performed at a temperature of 950 to 1,250°C. The melting time was 30 minutes (min). The molten glass composition in the melting step was rapidly cooled through dry and wet quenching. The rapidly cooled glass melt was pulverized into a powder state using a jet mill and a fine mill, and finally glass frit was obtained.

(2) Preparation of paste composition

Each of the glass frits of Examples 1 to 9 was added with a conductive powder, an organic vehicle, and an additive, and mixed to prepare each paste composition. Specifically, with respect to the total amount of each paste composition (100 wt%), the glass frit was 5 wt%, the aluminum powder having an average particle diameter of 3.0 ㎛ was 1 wt%, the conductive powder was 86 wt%, the organic vehicle was 6.5 wt%, and the additive was 1.5 wt%.

The conductive powder used was silver (Ag) powder (D50 particle size: 2.0 μm), and the organic vehicle used was a mixture of an organic binder, ethyl cellulose, and an organic solvent, (2,2,4-trimethyl-monoisobutyrate) at a weight ratio of 3:97. The additives used were a thixotropic agent (CRAYVALLAC) and a dispersant (Duomeen TDO). Specifically, the organic binder and the organic solvent were added in that order.

(3) Production of solar cells

Before forming the front electrode, an aluminum paste composition was applied to the back of a silicon wafer (sheet resistance: 85 Ω/sq.), which is a type of semiconductor substrate, and then dried to form the back electrode. The aluminum paste composition was printed and dried using a commercial product, DSCP-A151 (Dongjin Semichem), to form the front electrode. The drying was performed by maintaining it at 130° C. for 4 minutes (min) in an infrared drying furnace and then cooling it.

Thereafter, the paste compositions of Examples 1 to 9 manufactured in (2) above were used to form front electrodes, respectively. Each of the paste compositions was applied to the front surface of the silicon wafer on which the rear electrode was formed. The application was performed by a method of printing by screen printing in a certain pattern.

With both the rear electrode and the front electrode formed, firing was performed using a belt-type sintering furnace at a temperature of 770°C at a speed of 240 inch/min.

Comparative examples 1 to 5

Except that the glass frit compositions were prepared with the respective compositions of Comparative Examples 1 to 5 instead of Examples 1 to 9 in Tables 1 and 2 below, paste compositions and front electrodes were prepared by the same method, and solar cells were manufactured.

PbO
[mol%] SiO ₂
[mol%] ZnO
[mol%] B ₂ O ₃
[mol%] Al ₂ O ₃
[mol%] Ga ₂ O ₃
[mol%] Y ₂ O ₃
[mol%] Ag ₂ O
[mol%] Equation 1
([PbO]+
[ZnO]+
[Al ₂ O ₃ ]) Equation 2
([PbO]/
[ZnO ×[Al2O3]+
[Ag2O]] Example 1 56.2 14.9 12.9 11.4 4.0 - - 0.5 73.13 5.38 Example 2 55.1 14.6 12.7 11.2 3.9 - - 2.5 71.66 1.55 Example 3 53.7 14.3 12.4 10.9 3.8 - - 5.0 69.83 0.82 Example 4 53.1 14.1 12.2 10.8 3.8 - - 6.0 69.09 0.69 Example 5 54.5 13.0 11.5 10.0 4.0 3.5 3.5 - 70.00 13.63 Example 6 54.2 12.9 11.4 10.0 4.0 3.5 3.5 0.5 69.65 5.59 Example 7 53.1 12.7 11.2 9.8 3.9 3.4 3.4 2.5 68.25 1.66 Example 8 51.8 12.4 10.9 9.5 3.8 3.3 3.3 5.0 66.50 0.89 Example 9 51.2 12.2 10.8 9.4 3.8 3.3 3.3 6.0 65.80 0.75 Comparative Example 1 56.5 15.0 13.0 11.5 4.0 - - - 73.50 14.13 Comparative Example 2 52.5 14.0 12.1 10.7 3.7 - - 7.0 68.36 0.59 Comparative Example 3 52.3 13.9 12.0 10.6 3.7 - - 7.5 67.99 0.56 Comparative Example 4 50.7 12.1 10.7 9.3 3.7 3.3 3.3 7.0 65.10 0.64 Comparative Example 5 50.4 12.0 10.6 9.3 3.7 3.2 3.2 7.5 64.75 0.60

Looking at Table 1 above, it can be confirmed that Examples 1 to 9 satisfy Equations 1 and 2, and Comparative Examples 1 to 5 do not satisfy Equations 1 and 2.

Evaluation Example 1: Evaluation of Adhesion, Line Resistance, and Contact Resistance

For the glass frit, the paste composition, or the solar cell, the adhesion, line resistance, and contact resistance were evaluated, and the results of each evaluation are shown in Table 2 below. At this time, the specific evaluation conditions are as follows.

Adhesion : A ribbon (width 1.5 mm, thickness 0.2 mm) was aligned in a straight line on the island type bus bar of the front electrode of each solar cell, and bonding was performed using a tabbing machine while applying hot air at 150° C. For each bonded wafer, a peel test (180 degree condition) was performed using a universal material testing machine (NTS technology). In this regard, the adhesion recorded in Table 3 below is the highest point of the measured value in the peel test.

Line resistance : After printing, drying, and firing the electrode paste composition containing each of the above silver powders on a printing plate having a length of 20,000 ㎛ and a width of 60 ㎛, the line resistance was measured using a multimeter (Tektronix DMM 4020 device). Separately, the area was measured using a laser microscope (KEYENCE VK-X100). Thereafter, the line resistance was calculated by inputting each measured value into the following calculation formula 1, and recorded in Table 3.

[Calculation formula 1] Line resistance = (resistance × area) / length

Contact resistance : The contact resistance was measured using the Transfer Length Method (TLM), which is one of the widely known methods. Specifically, first, the electrode paste composition containing each of the above silver powders was printed on a wafer in a bar pattern (L*Z, 500㎛*3000㎛), and then a drying and firing process was performed. At this time, in order to suppress interference phenomenon when measuring the contact resistance, a laser was irradiated twice with a laser etching machine (Laser Etching Machine, hardram Company) at a frequency of 200 kHz and a pulse width of 50% to insulate the edge of the bar pattern. After that, the resistance was measured using a multimeter (Tektronix DMM 4020 device), and the slope and intercept of the resistance according to the interval were measured to obtain the contact resistance (Ri, R _total ). The measured contact resistance and area were entered into the calculation formula 2 below to calculate the contact resistance, which was then recorded in Table 3 below.

[Calculation formula 2] Contact resistance = Contact resistance × area

Line resistance
[μΩ cm] Contact resistance
[mΩ cm] Adhesion
[N] Example 1 2.7 1.9 2.1 Example 2 2.6 1.7 2.1 Example 3 2.6 1.6 2.1 Example 4 2.5 1.7 2.1 Example 5 2.8 1.6 2.2 Example 6 2.7 1.5 2.2 Example 7 2.5 1.4 2.1 Example 8 2.6 1.4 2.1 Example 9 2.6 1.5 2.1 Comparative Example 1 2.7 2.1 2.1 Comparative Example 2 2.7 2.1 2.0 Comparative Example 3 2.8 2.2 2.0 Comparative Example 4 2.7 1.8 2.0 Comparative Example 5 2.8 2.0 1.9

According to Table 2 above, in the case of Examples 1 to 9, all showed excellent adhesion exceeding 2.0 N, while showing a line resistance of lower than 3.0 uΩㆍcm and a contact resistance of lower than 2.0 mΩㆍcm2. In contrast, it can be confirmed that Comparative Example 1 has a higher contact resistance than the Example, Comparative Examples 2, 3, and 5 have higher contact resistance and lower adhesion than the Example, and Comparative Example 4 has a lower adhesion than the Example. This is due to the difference in the glass frit composition, and unlike Comparative Examples 1 to 5, Examples 1 to 9 all satisfied Table 1, showing excellent adhesion between the electrode and the semiconductor substrate, and thus showing lower line resistance and contact resistance.

Evaluation Example 2: Temperature Evaluation

For each of the above glass frit, temperature evaluation, specifically softening point and crystallization temperature, was performed, and the evaluation results are shown in Table 4 below. At this time, the specific evaluation conditions are as follows.

Softening Point: The glass transition temperature, also known as the softening point, is an important thermal characteristic in amorphous and semi-crystalline polymers. Each glass frit was applied to an aluminum pan, and a differential scanning calorimeter (DSC, TA Corporation) was used to measure the temperature while increasing it to 580°C at a heating rate of 10°C/min. The peak point where the endothermic reaction ends during the measurement was analyzed to confirm the Tg temperature, which was recorded in Table 4 below.

Highest peak temperature : Using the same equipment as that used for the softening point measurement above, and applying the same heating rate and temperature conditions, the highest peak point where the exothermic reaction was the highest during the measurement was analyzed to determine the Tp temperature, which was recorded in Table 4 below.

DSC Tg
(℃) Tp
(℃) Example 1 374.0 541.9 Example 2 373.2 541.6 Example 3 373.0 541.0 Example 4 372.7 540.8 Example 5 376.7 549.1 Example 6 374.3 548.8 Example 7 373.2 548.5 Example 8 372.1 547.6 Example 9 371.9 546.9

According to Table 3 above, for Examples 1 to 9, it was confirmed that the softening point was measured in an appropriate range of 330 to 400°C, and the highest peak temperature was measured in a range of 500 to 560°C.

The present invention is not limited to the above embodiments, but can be manufactured in various different forms, and a person having ordinary skill in the art to which the present invention pertains will understand that the present invention can be implemented in other specific forms without changing the technical idea or essential features of the present invention. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive.

10: Semiconductor substrate
10a: Lower semiconductor layer
10b: Upper semiconductor layer
20: Front electrode
30: Rear electrode

Claims (23)

It is a lead (Pb)-silicon (Si)-zinc (Zn) glass frit.
For the total amount of the above glass frit (100 mol%),
The first metal oxide, lead oxide (PbO), is contained in an amount of 51.0 to 60.0 mol%,
The second metal oxide, silicon oxide (SiO ₂ ), is contained in an amount of 8.0 to 19.0 mol%,
Zinc oxide (ZnO), a third metal oxide, is contained in an amount of 5.0 to 15.0 mol%,
The fourth metal oxide, boron oxide (B ₂ O ₃ ), is contained in an amount of 5.0 to 20.0 mol%,
The remainder contains aluminum oxide (Al ₂ O ₃ ), which is the fifth metal oxide.
A glass frit composition for forming an electrode of a solar cell satisfying the following formula 1.
<Formula 1>
65.5 ≤ [PbO] + [ZnO] + [Al ₂ O ₃ ] ≤ 73.4
([PbO], [ZnO], and [Al ₂ O ₃ ] in the above formula 1 represent the mol% of PbO, ZnO, and Al ₂ O _{3 ,} respectively.)
In the first paragraph,
A glass frit composition for forming an electrode of a solar cell containing 0.5 to 5.0 mol% of gallium oxide (Ga ₂ O ₃ ), which is a sixth metal oxide.
In the first paragraph,
A glass frit composition for forming an electrode of a solar cell containing 0.5 to 5.0 mol% of yttrium oxide (Y ₂ O ₃ ), which is a seventh metal oxide.
In the first paragraph,
A glass frit composition for forming an electrode of a solar cell containing 0.5 to 6.0 mol% of silver oxide (Ag ₂ O), which is an eighth metal oxide.
In the fourth paragraph,
A glass frit composition for forming an electrode of a solar cell satisfying the following formula 2.
<Formula 2>
0.60 ≤ [PbO]/([ZnO]×[Al ₂ O ₃ ]+[Ag ₂ O]) ≤ 14.0
(In the above formula 2, [PbO], [ZnO], [Al ₂ O ₃ ], and [Ag ₂ O] represent the mole (mol%) of PbO, ZnO, Al ₂ O ₃ , and Ag ₂ O, respectively.)
In the first paragraph,
A glass frit composition for forming an electrode of a solar cell, comprising 51.0 to 56.3 mol% of lead oxide (PbO), which is the first metal oxide.
In the first paragraph,
A glass frit composition for forming an electrode of a solar cell, comprising 1.0 to 5.0 mol% of aluminum oxide (Al ₂ O ₃ ), which is the fifth metal oxide.
In the first paragraph,
A glass frit composition for forming an electrode of a solar cell, wherein the line resistivity of the glass frit is less than 3.0 uΩㆍcm (excluding 0 uΩㆍcm).
In the first paragraph,
A glass frit composition for forming an electrode of a solar cell, wherein the contact resistance of the glass frit is less than 2.0 mΩㆍcm2 (excluding 0 mΩㆍcm2).
In the first paragraph,
A glass frit composition for forming an electrode of a solar cell, wherein the adhesion of the glass frit exceeds 2.0 N.
challenging powder;
glass frit; and
organic vehicle;
The above glass frit is a lead (Pb)-silicon (Si)-zinc (Zn) based glass frit.
For the total amount of the above glass frit (100 mol%),
The first metal oxide, lead oxide (PbO), is contained in an amount of 51.0 to 60.0 mol%,
The second metal oxide, silicon oxide (SiO ₂ ), is contained in an amount of 8.0 to 19.0 mol%,
Zinc oxide (ZnO), a third metal oxide, is contained in an amount of 5.0 to 20.0 mol%,
The fourth metal oxide, boron oxide (B ₂ O ₃ ), is contained in an amount of 5.0 to 20.0 mol%,
The remainder contains aluminum oxide (Al ₂ O ₃ ), which is the fifth metal oxide.
A paste composition for forming an electrode of a solar cell satisfying the following equation 1.
<Formula 1>
65.5 ≤ [PbO] + [ZnO] + [Al ₂ O ₃ ] ≤ 73.4
([PbO], [ZnO], and [Al ₂ O ₃ ] in the above formula 1 represent the mol% of PbO, ZnO, and Al ₂ O _{3 ,} respectively.)
.
In Article 11,
The above glass frit contains yttrium oxide (Y ₂ O ₃ ), which is a seventh metal oxide.
For the total amount of the above glass frit (100 mol%),
A paste composition for forming an electrode of a solar cell, wherein the seventh metal oxide, yttrium oxide (Y ₂ O ₃ ), is contained in an amount of 0.5 to 5.0 mol%.
In Article 11,
The above glass frit contains silver oxide (Ag ₂ O), which is an eighth metal oxide,
For the total amount of the above glass frit (100 mol%),
A paste composition for forming an electrode of a solar cell containing 0.5 to 6.0 mol% of silver oxide (Ag ₂ O), which is an eighth metal oxide.
In Article 13,
A paste composition for forming an electrode of a solar cell satisfying the following equation 2.
<Formula 2>
0.60 ≤ [PbO]/([ZnO]×[Al ₂ O ₃ ]+[Ag ₂ O]) ≤ 14.0
(In the above formula 2, [PbO], [ZnO], [Al ₂ O ₃ ], and [Ag ₂ O] represent the mole (mol%) of PbO, ZnO, Al ₂ O ₃ , and Ag ₂ O, respectively.)
In Article 11,
For the total amount of the above glass frit (100 mol%),
A paste composition for forming an electrode of a solar cell, comprising 1.0 to 5.0 mol% of aluminum oxide (Al ₂ O ₃ ), which is the fifth metal oxide.
In Article 11,
The above challenging powder is,
A paste composition for forming an electrode of a solar cell, comprising at least one conductive powder selected from the group consisting of silver (Ag) powder, silver (Ag)-containing alloy powder, aluminum (Al) powder, aluminum (Al)-containing alloy powder, copper (Cu) powder, aluminum (Al)-containing alloy powder, nickel (Ni) powder, and nickel (Ni)-containing alloy powder.
In Article 11,
The above organic vehicle is,
A paste composition for forming an electrode of a solar cell, comprising an organic binder and an organic solvent.
In Article 11,
A paste composition for forming an electrode of a solar cell further comprising an additive.
delete An electrode for a solar cell formed using a composition according to any one of claims 1 to 10.
An electrode for a solar cell formed using a composition according to any one of claims 11 to 18.
semiconductor substrate; and
A solar cell comprising an electrode according to claim 20, positioned on at least one surface of the semiconductor substrate.
semiconductor substrate; and
A solar cell comprising an electrode according to claim 21, positioned on at least one surface of the semiconductor substrate.