TW201422823A - A multicomponent-alloy material layer and a solar cell comprising the same - Google Patents

Abstract

A multicomponent-alloy material layer is provided, which is for back contacts of thin film solar cells. The multicomponent-alloy material layer is amorphous and includes at least two major metal elements, wherein the melting point of the at least one of a major metal element of the at least two major metal elements is higher than 1800 DEG C. The atomic percent of the major metal elements whose melting point is higher is more than 45 at% based on the overall atomic percent of the multicomponent-alloy material layer. A thin film solar cell is also provided, which includes a substrate, a back contact formed on the substrate and an absorber layer formed on the back contact, wherein the back contact is the multicomponent-alloy material layer. Due to the multicomponent-alloy material layer is amorphous, the structure of the multicomponent-alloy material layer is continuous, uniform and nearly without any pores or gaps. Thus, the adhesion between the substrate and the multicomponent-alloy material layer increases.

Description

Multi-layer alloy material layer and solar cell containing same

The present invention provides a material layer for a thin film solar cell, and more particularly a layer of a multi-element alloy material for a back electrode layer of a thin film solar cell. The present invention also provides a thin film solar cell comprising the back electrode layer formed of the foregoing multi-alloy material.

A method for fabricating a thin film solar cell (for example, a copper indium gallium diselenide (CIGS) thin film solar cell) includes the steps of: sputtering a back electrode layer on a substrate; patterning the back electrode layer; A CuGa/In precursor layer is grown on the patterned back electrode layer; the copper indium gallium precursor layer is selenized to form a P-type CIGS semiconductor absorber layer; and the CIGS P type is formed Forming an n-type semiconductor buffer layer on the semiconductor absorber layer; depositing a window layer on the n-type semiconductor buffer layer; depositing a front electrode on the window layer; and plating a metal contact on the front electrode. Among them, molybdenum metal is most commonly used as a material of the back electrode layer in the prior art because of its low electrical resistance and high compressive stress at low sputtering pressure.

However, the prior art selenide CuGa / In precursor layer of the step, the metal back electrode layer is molybdenum selenide, after easily formed of molybdenum diselenide (MoSe _2), MoSe although the thickness is less than 50 nanometers (nm), ₂ may be as the ohmic contact layer, thereby reducing the contact resistance value of the thin film solar cell; however, to control the thickness of less than 50 nm MoSe _2, but must be precisely controlled via the selenide CuGa / in precursor layer of time to reach. If the selenization time is too short, the composition of the P-type CIGS semiconductor absorption layer is not uniform, thereby degrading the conversion efficiency of the fabricated solar cell; if the selenization time is too long, the thickness of the MoSe ₂ is too thick, and the thin film solar cell is increased. Contact resistance. Therefore, the use of molybdenum metal as the material of the back electrode layer easily affects the photoelectric characteristics of the thin film solar cell.

Further, when a thin film solar cell uses molybdenum metal as a material of the back electrode layer, the molybdenum metal formed on the substrate is susceptible to stress and cannot obtain desired adhesion on the substrate, thereby deteriorating the conversion efficiency of the thin film solar cell.

Therefore, in order to solve the above problems, the prior art requires very careful control of process parameters, such as process pressure and sputtering rate, in order to improve the adhesion to the substrate due to the stress of the molybdenum metal film. However, such a solution may impose limitations on the fabrication method of the thin film solar cell. If the process parameters are not well controlled, the photoelectric conversion efficiency of the thin film solar cell will be significantly reduced.

The main object of the present invention is to solve the problem that the adhesion of the molybdenum metal film to the substrate is unfavorable due to the influence of the stress of the molybdenum metal film when the conventional molybdenum metal film is formed on the substrate.

In order to meet the above object, the present invention provides a multi-alloy material layer for a back electrode layer of a thin film solar cell, which is an amorphous structure, the composition of which comprises at least two main metal elements, and the at least two The melting point of at least one of the main metal elements is greater than 1800 ° C, based on the total content of the multi-alloy material layer, the total metal element content of the melting point greater than 1800 ° C is greater than 45 atomic percent (at %) .

According to the present invention, the main gold having a melting point greater than 1800 ° C according to the present invention The genus elements are, for example but not limited to, zirconium, hafnium, molybdenum, niobium, tungsten or tantalum.

According to the present invention, the multi-alloy material layer of the present invention utilizes at least one of the main metal elements to have a melting point of more than 1800 ° C and based on the total content of the multi-alloy material layer. The metal element content is a technical feature of greater than 45 atomic percent (at%), such that the major metal elements are formed by any process to form a multi-alloy material layer that is an amorphous structure, such as, but not limited to, a splash. Plating or evaporation deposition, etc.

According to the present invention, the back electrode layer of the present invention refers to a layered structure interposed between a substrate and an absorbing layer in a thin film solar cell, which has the function of increasing the utilization rate of light, so that the absorbing layer is penetrated but not absorbed. The light absorbed by the layer is reflected by the back electrode layer and then absorbed by the absorption layer.

The multi-alloy material layer for thin film solar cells of the present invention has the following advantages:

1. Since the multi-alloy material layer is amorphous, the structure is very continuous and uniform, and there is no columnar crystal structure, and there is almost no void in the material layer, so the multi-alloy material layer has almost no internal stress, and thus The soda-lime glass can be matched and has no internal stress. Therefore, when the multi-component alloy material layer is used for the back electrode layer, the adhesion to the substrate is greatly increased, thereby reducing the probability of the back electrode layer peeling off from the substrate.

2. The amorphous structure can promote the surface flatness advantage. When the multi-alloy material layer is used as the back electrode layer of the thin film solar cell, the crystal grains of the absorption layer grown thereon can be increased, so that it can be advantageous. In order to obtain an absorption layer with good performance; further, the amorphous structure can reduce the activity of the multi-layer alloy material layer, and can ensure that the back electrode layer containing the multi-layer alloy material layer is not shaped The absorption layer formed thereon generates a reaction, so that the growth of the absorption layer is not affected at all in the process.

3. Since the multi-alloy material layer contains at least one main metal element having a melting point of more than 1800 ° C, the melting point of the multi-alloy material layer of the present invention can be improved, so that a high process can be withstood when preparing a thin film solar cell. The temperature is not easily damaged by temperature, thereby producing a thin film solar cell with better performance.

4. Compared with the prior art, the back electrode made of molybdenum metal having a columnar crystal structure, the amorphous alloy material layer provided by the present invention is a material which is significantly different from the back electrode layer of the prior art. Moreover, the application to the back electrode layer does have a large increase in adhesion to the substrate, low activity, no reaction with the absorption layer, and an increase in crystal grains of the absorption layer, and is a major breakthrough.

Preferably, the composition of the multi-alloy material layer contains between two and ten major metal elements.

Preferably, the main metal elements have a melting point of not less than 600 ° C.

According to the present invention, the melting points of the main metal elements of the present invention are not less than 600 ° C, meaning that the melting point of the main metal elements except the at least one main metal element is greater than 1800 ° C, and the remaining main metal elements The melting point is not less than 600 ° C.

According to the present invention, since the melting point of the main metal element of the multi-alloy material layer is not less than 600 ° C, the melting point of the multi-element alloy material layer can be increased, so that a high process temperature can be withstood when preparing a thin film solar cell. It is not easily damaged by temperature, and thus produces a thin film solar cell with better performance.

Preferably, the multi-alloy material layer has a melting point greater than 600 ° C.

According to the present invention, since the melting point of the multi-alloy material layer is greater than 600 ° C, it can be used to prepare the back electrode layer of the thin film solar cell, which can reduce the influence of the process temperature. For example, the CIGS solar cell must be prepared at about 600 ° C in the preparation. The selenization step is carried out so that the multi-alloy material layer of the present invention is not affected by the selenization step.

Preferably, the main metal elements are selected from the group consisting of aluminum, boron, lanthanum, carbon, calcium, cobalt, chromium, copper, lanthanum, molybdenum, niobium, tantalum, titanium, niobium, vanadium, tungsten. , zirconium, hafnium, silver and nickel.

Preferably, the metal elements are selected from the group consisting of ruthenium, osmium, iridium, titanium, zirconium, copper, aluminum, and nickel.

Preferably, the multi-alloy material layer is selected from the group consisting of a layer of niobium-titanium-zirconium alloy material and a layer of zirconium-copper-aluminum alloy material.

According to the present invention, when the multi-alloy material layer of the present invention is a layer of yttrium-titanium-zirconium alloy material, the reflectance is in the range of visible light and near-infrared light, and the reflectance is 65 to 90%, which is significantly larger than that of the molybdenum metal film. The reflectivity, the maximum difference can even exceed 20%. Therefore, since the NbSiTaTiZr alloy material layer is applied to the back electrode layer of the thin film solar cell, the light utilization rate can be improved, and the light that penetrates the absorption layer but is not absorbed by the absorption layer passes through the NbSiTaTiZr alloy material as the back electrode layer. After the layer is reflected, it is absorbed by the absorption layer, thereby increasing the short-circuit current density of the thin film solar cell.

Preferably, each major metal element is greater than 5 atomic percent (at%) based on the total content of the metal elements of the multicomponent alloy film.

Preferably, based on the total content of the metal elements of the multi-alloy film Standard, each major metal element is between 5 and 35 at%. The present invention further provides a thin film solar cell comprising a substrate, a back electrode layer formed on the substrate, and an absorbing layer formed on the back electrode layer, wherein the back electrode layer is the aforementioned multi-alloy material layer .

According to the present invention, the thin film solar cell of the present invention is, for example but not limited to, Cu ₂ ZnSnS ₄ (copper zinc tin sulfide, CZTS) solar cell, copper zinc tin selenide (Cu ₂ ZnSnSe ₄ , copper zinc) Tin selenide, CZTSe) solar cell, copper indium gallium diselenide (CIGS) solar cell, copper indium gallium sulfur selenide (CIGSSe) solar cell or copper zinc tin sulphide (copper Zn sulphide) Selenide, CZTSSe).

In accordance with the present invention, the substrate of the present invention is, for example but not limited to, glass, ceramic, graphite or metal.

Preferably, the substrate is soda lime glass.

Preferably, the substrate is a flexible substrate.

According to the present invention, the material of the flexible substrate of the present invention is a flexible material such as, but not limited to, a polymer material or stainless steel. The polymer material is, for example but not limited to, polyimide (PI), polyethylene terephthalate (PET) or polyethersulfone (PES).

Preferably, the absorbing layer is selected from the group consisting of copper zinc tin sulphide, copper indium gallium selenide, cadmium sulfide, cadmium telluride, copper indium gallium sulphide selenide, copper zinc tin sulphide selenium, copper indium selenium, and Copper, zinc, tin and selenium.

According to the present invention, the thin film solar cell of the present invention further includes a buffer layer on the absorbing layer and a window on the buffer layer. A layer, a front electrode on the window layer, and a metal contact on the front electrode. Wherein, the buffer layer is, for example but not limited to, cadmium sulfide, zinc sulfide, zinc selenide or indium sulfide; the window layer is, for example but not limited to, zinc oxide; the front electrode is, for example but not limited to, zinc aluminum oxide, zinc oxide boron, Zinc oxide gallium, indium tin oxide or zinc gallium indium oxide; the metal contact is, for example but not limited to, aluminum, nickel, aluminum nickel alloy, copper or silver.

The multi-alloy material layer for thin film solar cells of the present invention has the following advantages:

1. Since the back electrode layer is formed of a multi-layer alloy material layer of an amorphous structure, the adhesion between the back electrode layer and the substrate can be improved, thereby reducing the probability of the back electrode layer falling off from the substrate.

2. Since the surface of the back electrode layer has good flatness, it can facilitate the formation of the absorption layer, thereby increasing the grain size of the absorption layer, and obtaining excellent performance of the thin film solar cell.

3. When the substrate of the thin film solar cell of the present invention is a flexible substrate, since the multi-alloy material layer is an amorphous structure, the multi-alloy material layer has almost no internal stress, so its internal stress-free property can be matched. The flexible substrate has a large increase in adhesion to the flexible substrate, and further reduces the probability of peeling off from the flexible substrate. Therefore, when it is applied to a flexible thin film solar cell, the industrial applicability is greatly increased.

In order to understand the technical features and practical functions of the present invention in detail, and in accordance with the contents of the specification, the drawings and preferred embodiments are further described to illustrate the technical means for the purpose of the present invention.

The sources of the samples described in the experimental preparation process of the following examples are And the composition ratio is as follows;

Nb: purity is greater than 99.9%.

矽 (Si): The purity is greater than 99.9%.

钽 (Ta): The purity is greater than 99.9%.

Titanium (Ti): purity greater than 99.9%.

Zirconium (Zr): purity greater than 99.9%.

Copper (Cu): purity greater than 99.9%.

Aluminum (Al): purity greater than 99.9%.

Nickel (Ni): purity greater than 99.9%.

The model of the spectrometer described in the preparation process of the present invention: V-670 (Jasco, Japan)

Model of the Pyris diamond thermomechanical analyzer: Diamond TMA.

Example 1

In this embodiment, a niobium-titanium-zirconium-zirconium (NbSiTaTiZr) target is prepared, and the NbSiTaTiZr target is sputtered to form a layer of NbSiTaTiZr alloy material on a soda lime glass, thereby obtaining the embodiment. For the combination of the soda lime glass/NbSiTaTiZr alloy material layer, the detailed preparation method is as follows: preparing the bismuth raw material, the bismuth raw material, the titanium raw material, the bismuth raw material and the zirconium raw material, and the molar number of each raw material is equal, and is cooled by water. The copper crucible vacuum induction electric furnace melts the raw materials, and the melting step is repeated five times, so that the raw materials are completely uniformly mixed in the water-cooled copper crucible, and after the uniformly mixed raw materials are solidified, a The primordial embryo was mechanically treated to obtain a NbSiTaTiZr circular target having a diameter of 2 Å.

Here, a soda lime glass is prepared, and a NbSiTaTiZr alloy material layer is formed on the soda lime glass by using the above-mentioned NbSiTaTiZr round target by magnetron sputtering to obtain a soda lime glass by using the following sputtering parameters. /NbSiTaTiZr alloy material layer combination: the background pressure of the sputtering system is 4.5×10 ^-7 Torr, the working gas system is argon, the working pressure is 5 milliTorr (mTorr), the magnetic control DC RF The power is 150 watts (W); the thickness of the NbSiTaTiZr alloy material layer is 637 nm.

Referring to FIG. 1, there is a peak at 37.79 degrees at 2θ, and another peak at 64.09 degrees at 2θ. Therefore, it can be seen from the figure that the layer of NbSiTaTiZr alloy material of the present embodiment has an amorphous structure.

Example 2

In this embodiment, a zirconium copper aluminum nickel (ZrCuAlNi) target is prepared, and a ZrCuAlNi alloy material layer is formed on a soda lime glass by sputtering using a ZrCuAlNi target, thereby obtaining the embodiment. The combination of the soda lime glass/ZrCuAlNi alloy material layer is prepared in the following manner: preparing a zirconium raw material, a copper raw material, an aluminum raw material, and a nickel raw material, and the atomic percentages of each raw material are 55 at%, 30 at%, respectively. 10 at% and 5 at%, the subsequent preparation steps of the ZrCuAlNi target of the present embodiment are substantially as described in Embodiment 1, and will not be described herein. In the present example, the ZrCuAlNi target produced had a diameter of 6 inches.

Here, a soda-lime glass is prepared, and the ZrCuAlNi target is used, and a ZrCuAlNi alloy material layer is formed on the soda-lime glass by magnetron sputtering to obtain a soda-lime glass by the following sputtering parameters. Combination of glass/ZrCuAlNi alloy material layer: the background pressure of the sputtering system is 2×10 ^-6 Torr, the working gas system is argon gas, and the flow rate of argon gas is standard state 40 ml/min (standard cubic centimeter per minute, sccm ), the working pressure is 3 mTorr, the magnetically controlled DC RF power is 300 W, the pulse frequency is 20 kHz, the reverse time is 5 microseconds, and the substrate bias is -100 volts (V). The substrate temperature is room temperature, the rotation speed of the stage is 10 revolutions per minute, and the sputtering time is 3 hours; as shown in FIG. 2 and FIG. 3, the thickness of the ZrCuAlNi alloy material layer is 1.031 μm, and The structure of the ZrCuAlNi alloy material layer is dense.

Referring to FIG. 4, there is a peak at 2θ of 26.5 degrees and another wide peak at 58 degrees of 2θ. Therefore, it can be seen from the figure that the ZrCuAlNi alloy material layer of the present embodiment has an amorphous structure.

Comparative example 1

In the comparative example, a molybdenum metal film is formed on the soda lime glass by magnetron sputtering, thereby obtaining a soda lime glass/molybdenum metal film combination of the comparative example: a sputtering system The background pressure is 4.5×10 ^-7 Torr, the working gas system is argon, the working pressure is 8 mTorr, the magnetron DC RF power is 90 W, and the substrate temperature is 0.2 at room temperature. Hour; the thickness of the molybdenum metal film is 700 nm.

Test Example 1: Surface Topography

In this test example, a cross-sectional view of the soda lime glass/NbSiTaTiZr alloy material layer of Example 1 and a surface morphology of the NbSiTaTiZr alloy material layer and a cross section of the soda lime glass/molybdenum metal film combination of Comparative Example 1 were observed by a scanning electron microscope. The surface and the surface topography of the molybdenum metal film were used to observe the structural differences between Example 1 and Comparative Example 1.

Please refer to FIG. 5 and FIG. 6 , compared with the molybdenum metal of Comparative Example 1. The film, since the NbSiTaTiZr alloy material layer of the embodiment 1 is an amorphous structure, the structure thereof is very continuous and uniform, without any columnar crystal structure, and there is almost no void in the material layer, so the NbSiTaTiZr alloy material layer has almost no internal stress. Therefore, the soda-lime glass can be matched and has no internal stress, so the adhesion of the NbSiTaTiZr alloy material layer to the soda-lime glass is good: and the molybdenum metal film of Comparative Example 1 can be seen to have a distinct columnar crystal structure, and Since there are many voids between the columnar crystal structures, the molybdenum metal film has high internal stress and thus has poor adhesion to soda lime glass.

Referring to FIG. 7 and FIG. 8 , it can be seen that the surface of the molybdenum metal film of Comparative Example 1 is rough, and the surface of the NbSiTaTiZr alloy material layer of Embodiment 1 is relatively flat, so the application of the NbSiTaTiZr alloy material layer is compared with the molybdenum metal film. When the back electrode layer of the thin film solar cell is prepared, the crystal grains formed on the absorption layer of the NbSiTaTiZr alloy material layer can be increased, which is advantageous for obtaining an absorption layer with good performance.

Test Example 2: Melting point of NbSiTaTiZr alloy material layer

This test is a thermomechanical analysis instrument that measures the expansion and contraction of each sample between 600 and 1200 °C, thereby measuring the glass transition temperature (Tg) or thermal expansion coefficient. The data was measured, and the melting point of the NbSiTaTiZr alloy material layer in the combination of the soda lime glass/NbSiTaTiZr alloy material layer of Example 1 was measured. It can be known from the results of the test examples that the melting point of the NbSiTaTiZr alloy material layer is about 900 ° C. Therefore, when the NbSiTaTiZr alloy material layer is applied to prepare the back electrode layer of the thin film solar cell, especially in the preparation process, it needs to be about 600 ° C. For a selenized thin film solar cell, the NbSiTaTiZr alloy material layer is not affected by the selenization step.

Test Example 3: Reflectance

In this test example, the reflectance of the NbSiTaTiZr alloy material layer in the combination of the soda lime glass/NbSiTaTiZr alloy material layer of Example 1 and the molybdenum metal film in the soda lime glass/molybdenum metal film combination of Comparative Example 1 was measured by a spectrometer. The measured wavelengths range from 300 nm to 1800 nm.

Referring to FIG. 9, in the visible light and near-infrared light range (wavelength between 400 and 1200 nm), the reflectance of the molybdenum metal film of Comparative Example 1 is less than 85%, and in the shorter wavelength range (wavelength) Between 400 and 900 nm, the molybdenum metal film has a relatively low reflectance of between about 60 and 70%.

In contrast, the NbSiTaTiZr alloy material layer of the first embodiment has a reflectance significantly larger than that of the molybdenum metal film in the range of wavelengths between 400 and 1200 nm, and the reflectance of the wavelength of 800 nm is most significant. The reflectance of the NbSiTaTiZr is higher than the reflectance of the molybdenum metal film by more than 20%. Therefore, since the NbSiTaTiZr alloy material layer has a good reflectance, when applied to the back electrode layer of the thin film solar cell, the light utilization rate can be increased, and light that penetrates the absorption layer but is not absorbed by the absorption layer can be passed through the back electrode. After the layer of NbSiTaTiZr alloy material is reflected, it is absorbed by the absorption layer.

Test Example 4: Atomic percentage

In this test example, the atomic percentages of the respective components of the ZrCuAlNi target and the ZrCuAlNi alloy material layer of Example 2 were analyzed by electron probe light microscopy, and the results are shown in Table 1.

Table 1: Atomic percentage of each component of the ZrCuAlNi target and the ZrCuAlNi alloy material layer

As shown in Table 1, the content of Zr is 46.7 ± 0.6 atomic percent based on the total content of the ZrCuAlNi alloy material layer.

Test Example 5: Surface average roughness

In this test example, the surface topography of the ZrCuAlNi alloy material layer of Example 2 was analyzed by atomic force microscopy to obtain the surface roughness (Ra) of the ZrCuAlNi alloy material layer. As a result, as shown in FIG. 10, the ZrCuAlNi alloy was used. The surface roughness of the material layer is 0.35 nm, that is, the surface roughness of the ZrCuAlNi alloy material layer is extremely low, so the surface of the ZrCuAlNi alloy material layer is flat, so it is beneficial when applied to the back electrode layer of the thin film solar cell. Formation of an absorbing layer.

Test Example 6:

The test example is a combination of the soda lime glass/NbSiTaTiZr alloy material layer of the first embodiment and the soda lime glass/molybdenum metal film combination of the comparative example 1, and a copper indium gallium selenide (copper indium) is formed by the same process parameters and conditions. Gallium diselenide (CIGS) absorbing layer on the NbSiTaTiZr alloy material layer of the combination of soda lime glass/NbSiTaTiZr alloy material layer and molybdenum metal film combined with soda lime glass/molybdenum metal film, thereby obtaining one soda lime glass/NbSiTaTiZr alloy respectively a combination of a material layer/CIGS absorber layer and a combination of a soda lime glass/molybdenum metal film/CIGS absorber layer and The grain size of the CIGS absorber layer in the two combinations was measured by a scanning electron microscope.

Referring to FIG. 11 and FIG. 12, it can be seen that the combination of the soda lime glass/NbSiTaTiZr alloy material layer/CIGS absorption layer is a soda lime glass, a NbSiTaTiZr alloy material layer and a CIGS absorption layer from bottom to top, wherein CIGS absorption The grain size of the layer is between 500 and 1000 nm, and the combination of soda-lime glass/molybdenum metal film/CIGS absorber layer is composed of soda-lime glass, molybdenum metal film and CIGS absorber layer from bottom to top. The CIGS absorber layer has a grain size between about 100 and 300 nm. Therefore, it can be seen from the test example that since the surface of the NbSiTaTiZr alloy material layer is flat, the crystal grains of the absorption layer formed on the NbSiTaTiZr alloy material layer can be significantly increased, which is advantageous for obtaining an absorption layer having good properties.

Example 3

In this embodiment, a CIGS solar cell is prepared by using a combination of the soda lime glass/NbSiTaTiZr alloy material layer of the embodiment 1, and the detailed preparation method is as follows: the combination of the soda lime glass/NbSiTaTiZr alloy material layer of the embodiment 1 is prepared, Wherein the NbSiTaTiZr alloy material layer is used as a back electrode layer; the back electrode layer is patterned; a CuGa/In precursor layer is grown on the patterned back electrode layer; and the CuGa/In precursor layer is selenized to form a CIGS absorber layer; forming a cadmium sulfide (CdS) buffer layer on the CIGS absorber layer; depositing a zinc oxide (ZnO) window layer on the CdS buffer layer; depositing a zinc zinc oxide (AZO) front electrode The layer is on the ZnO window layer; and the metal contact layer of the nickel-aluminum alloy is plated on the AZO front electrode layer to obtain the CIGS solar cell of the embodiment.

Comparative example 2

In this embodiment, a CIGS solar cell is prepared by combining the soda lime glass/molybdenum metal film of Comparative Example 1, and the detailed preparation method is substantially as described in Embodiment 3, and will not be described here, and each process parameter and embodiment are not described. 3 is identical except that the comparative example is provided with the soda lime glass/molybdenum metal film combination of Comparative Example 1, and the molybdenum metal film is used as the back electrode layer.

Test Example 7

This test example measures the characteristic parameters of the CIGS solar cells of Example 3 and Comparative Example 2, thereby comparing the performance difference between the two, and the results are shown in Table 2 and shown in Figs. 13 to 14.

It can be seen from Table 2 and FIG. 13 to FIG. 14 that, compared with Comparative Example 2, since the structure of the NbSiTaTiZr alloy material layer is very continuous and uniform, there is no columnar crystal structure, and there is almost no void in the material layer, so it is combined with sodium. Since the adhesion of the calcium glass is good, the probability of cracking and peeling is lowered, so that the leakage current is effectively reduced. Therefore, the parallel resistance of the CIGS solar cell of the third embodiment is significantly increased by 70%.

Further, as described in Test Example 1, since the surface of the NbTaTiSiZr alloy material layer is flat, the CIGS absorption layer of the CIGS solar cell of Example 3 has a larger crystal grain and is flatter, thereby having better photoelectric conversion capability. And the effect of directly reducing the carrier loss, thus increasing the short-circuit current density, that is, the short-circuit current density of the CIGS solar cell of Example 3 is higher than the short-circuit current density of the CIGS solar cell of Comparative Example 2, which proves the CIGS absorption layer of Example 3. The crystal grains were larger than those of the absorption layer of Comparative Example 2.

Further, the short-circuit current density of the CIGS solar cell of the third embodiment is significantly higher, and the degree of improvement is about 7.3%, that is, the photocurrent of the CIGS solar cell of the third embodiment is larger, because the test example 3 is As described above, since the reflectance of the NbSiTaTiZr alloy material layer is better than that of the molybdenum metal film, the light reflected from the NbSiTaTiZr alloy material layer back to the CIGS absorption layer can be absorbed by the CIGS absorption layer and used to convert it into a photocurrent. The short-circuit current density of the CIGS solar cell of Example 3 was increased.

Further, since the series resistance of the CIGS solar cell of the third embodiment is lower than that of the series resistance of the comparative example 2, the degree of reduction is 13.6%, so that the solar cell of the third embodiment has a small ohmic loss, so the NbSiTaTiZr alloy The material layer and the CIGS absorber layer are more excellent ohmic contact, thereby improving the conversion efficiency of the solar cell of the CIGS solar cell of Example 3. Compared with Comparative Example 2, the conversion efficiency of the CIGS solar cell of Example 3 is increased. 8.5%.

As can be seen from FIG. 14, the CIGS solar cell of Example 3 has higher quantum efficiency than the CIGS solar cell of Comparative Example 1 in the range of wavelength between 600 and 1000 nm, as in Test Example 3. The reason is that the reflectivity of the NbSiTaTiZr alloy material layer is better than that of the molybdenum metal film, and the reflectance of the NbSiTaTiZr is higher than that of the molybdenum metal film at a wavelength of about 800 nm. Therefore, the quantum efficiency of the third embodiment is higher than that of the comparative example 1. Obvious.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is an X-ray diffraction pattern of a layer of NbSiTaTiZr alloy material of Example 1 of the present invention.

2 is a field-emission scanning electron microscope (FE-SEM) image of a ZrCuAlNi alloy material layer according to Embodiment 2 of the present invention, and the magnification is 20,000 times.

3 is a field-emission scanning electron microscope (FE-SEM) image of a ZrCuAlNi alloy material layer according to Embodiment 2 of the present invention, and the magnification is 40,000 times.

4 is an X-ray diffraction pattern of a ZrCuAlNi alloy material layer of Example 2 of the present invention.

Fig. 5 is a cross-sectional view showing a scanning electron microscope of Example 1 of the present invention.

Fig. 6 is a cross-sectional view showing a scanning electron microscope of Comparative Example 1 of the present invention.

Fig. 7 is a view showing the surface topography of a scanning electron microscope of Example 1 of the present invention.

Fig. 8 is a view showing the surface topography of a scanning electron microscope of Comparative Example 1 of the present invention.

Fig. 9 is a reflectance spectrum diagram of the NbSiTaTiZr alloy material layer of Example 1 of the present invention and the molybdenum metal film of Comparative Example 1.

Figure 10 is a layer of ZrCuAlNi alloy material of Example 2 of the present invention. The surface topography obtained using an atomic force microscope.

Figure 11 is a cross-sectional image view of a scanning electron microscope of a combination of a soda lime glass/NbSiTaTiZr alloy material layer/CIGS absorber layer of Test Example 6 of the present invention.

Fig. 12 is a view showing the surface topography of a scanning electron microscope of a combination of a soda lime glass/molybdenum metal film/CIGS absorbing layer of Test Example 6 of the present invention.

Fig. 13 is a graph showing short-circuit current density and voltage of a CIGS solar cell of Example 3 and Comparative Example 2 of the present invention.

Fig. 14 is a graph showing quantum efficiency of a CIGS solar cell of Example 3 and Comparative Example 2 of the present invention.

Claims (13)

A multi-layer alloy material layer for a back electrode layer of a thin film solar cell, which is an amorphous structure, the composition of which comprises at least two main metal elements, and at least one of the at least two main metal elements The melting point of the element is greater than 1800 ° C, and the total content of the main metal element having a melting point greater than 1800 ° C is greater than 45 atomic percent (at %) based on the total content of the multi-alloy material layer. The multi-alloy material layer according to claim 1, the composition of which comprises between two and ten main metal elements. The multi-alloy material layer according to claim 1 or 2, wherein the main metal elements have a melting point of not less than 600 °C. The multi-alloy material layer according to claim 3, which has a melting point of more than 600 ° C. The multi-alloy material layer according to claim 4, wherein the main metal elements are selected from the group consisting of aluminum, boron, lanthanum, carbon, calcium, cobalt, chromium, copper, lanthanum, molybdenum, niobium, Niobium, titanium, tantalum, vanadium, tungsten, zirconium, hafnium, silver and nickel. The multi-alloy material layer of claim 5, wherein the main metal elements are selected from the group consisting of ruthenium, osmium, iridium, titanium, zirconium, copper, aluminum, and nickel. The multi-alloy material layer according to claim 6, which is selected from the group consisting of a layer of niobium-titanium-zirconium alloy material and a layer of zirconium-copper-aluminum alloy material. The multi-alloy film according to claim 7, wherein the content of each major metal element is greater than 5 atoms based on the total content of the multi-component alloy film. Percentage (at%). The multi-alloy film according to claim 8, wherein the main metal element is between 5 and 60 at% based on the total content of the multi-alloy film. A thin film solar cell comprising a substrate, a back electrode layer formed on the substrate, and an absorber layer formed on the back electrode layer, wherein the back electrode layer is one of claims 1 to 9 The multi-alloy material layer described in the item. The thin film solar cell of claim 10, wherein the substrate is soda lime glass. The thin film solar cell of claim 10, wherein the substrate is a flexible substrate. The thin film solar cell of any one of claims 10 to 12, wherein the absorbing layer is selected from the group consisting of copper zinc tin sulphide, copper indium gallium selenide, cadmium sulfide, cadmium telluride, copper indium Gallium sulphide selenium, copper zinc tin sulphide selenium, copper indium selenium, and copper zinc tin selenium.