CN103606589A - Amorphous silicon film solar cell and manufacturing method thereof - Google Patents

Abstract

The invention discloses an amorphous silicon thin-film solar cell and a manufacturing method thereof, comprising the steps of: providing a substrate; depositing a transparent conductive front electrode layer on the surface of the substrate; depositing an amorphous silicon top layer on the surface of the transparent conductive front electrode layer The stacked battery layer of the battery; a conductive back electrode layer is deposited on the surface of the stacked battery layer; wherein, the intrinsic layer of the amorphous silicon top battery is deposited in four steps from the P layer to the N layer, and the layer near the P layer The first layer deposits an amorphous silicon layer with a high hydrogen dilution ratio; the second layer deposits the first amorphous silicon layer; the third layer deposits a main body layer, and the fourth layer deposits a second amorphous silicon layer. The method of the invention well solves the contradiction between cost and quality in the process of industrialization through simple deposition process control and combination optimization, that is, the contradiction between high-speed deposition and high-quality amorphous silicon material.

Description

Amorphous silicon thin film solar cell and manufacturing method thereof

technical field

The invention relates to the technical field of photovoltaic solar cells, in particular to an amorphous silicon thin-film solar cell and a manufacturing method thereof.

Background technique

Silicon-based thin-film solar cells, especially the multi-stack cell structure combining amorphous silicon and microcrystalline silicon, have become the most competitive alternative cells in the field of solar photovoltaics, and the efficiency of industrialized cells has reached 10%. . At present, the photoelectric conversion efficiency of this multi-stack battery is still low, and it is necessary to further increase the conversion efficiency to more than 12%. However, the improvement of efficiency depends on the introduction of new processes or new structures to improve the effective absorption of light, reduce the structural defects of the cell and increase the voltage and current of the cell.

Silicon-based thin-film solar cells have achieved rapid development in laboratory research and industrialization in recent years due to their special advantages, such as large-area continuous production, relatively low cost, and abundant raw materials. Whether it is an amorphous silicon single-junction battery, an amorphous silicon/microcrystalline silicon stacked battery, or an amorphous silicon/amorphous silicon germanium/microcrystalline silicon triple-junction battery, the top layer of the battery stack structure is an amorphous silicon battery. That is, the material of the power generation active layer of the top cell is the intrinsic layer of amorphous silicon. Since Staebler and Wronski discovered the light-induced degradation of amorphous silicon materials in 1977, many research institutions and researchers have devoted themselves to developing amorphous silicon solar cells with high light stability and low light-induced degradation. The method of reducing the light-induced attenuation of amorphous silicon mainly starts from two aspects: 1) adopt double-junction or triple-junction laminated cells to reduce the thickness of the amorphous silicon power generation layer; 2) adopt high-quality amorphous intrinsic layer. However, amorphous silicon materials with high quality and relatively dense structure generally need to be realized by low-speed deposition methods such as high hydrogen dilution ratio and low deposition power. For industrialization, a low deposition rate means low equipment output and high investment costs. Therefore, it is a necessary condition for industrialization to deposit an intrinsic layer of amorphous silicon using a high-speed thin film deposition process.

Contents of the invention

Therefore, the object of the present invention is to provide a kind of manufacture method of amorphous silicon thin-film solar cell, comprising steps:

Provide the substrate;

Depositing a transparent conductive front electrode layer on the surface of the substrate;

Depositing a stacked cell layer comprising an amorphous silicon top layer cell on the surface of the transparent conductive front electrode layer;

Depositing a conductive back electrode layer on the surface of the laminate battery layer;

Wherein, the intrinsic layer of the amorphous silicon top cell is deposited in four steps from the P layer to the N layer, and the first layer near the P layer is deposited with an amorphous silicon layer with a high hydrogen dilution ratio; the second layer is deposited with the first amorphous silicon layer. a crystalline silicon layer; the third layer deposits the main body layer, and the fourth layer deposits the second amorphous silicon layer.

The stacked battery layer includes an amorphous silicon PIN or NIP single junction battery, an amorphous silicon/microcrystalline silicon stacked battery, or an amorphous silicon/amorphous silicon germanium/microcrystalline silicon triple junction battery.

The deposition conditions of the amorphous silicon layer with high hydrogen dilution ratio are high hydrogen dilution ratio, H ₂ /SiH ₄ is 5-15, deposition pressure is 0.3-0.5mbar, power density is 180-280W/m ² , the film layer The thickness is 5-30nm.

The deposition conditions of the first amorphous silicon layer are: the ratio of _H2 / _SiH4 is 4-10, the deposition pressure is 0.3-0.5mbar, the power density is 100-160W/ ^m2 , and the film thickness is 20-60nm .

The main body layer 4 is a high-speed deposition layer, the deposition rate is above 4A/s, the ratio of H ₂ /SiH ₄ is 1-4, the deposition pressure is 0.4-0.7mbar, and the power density is 220-280W/m ² . The thickness is 100-400nm.

The deposition conditions of the second amorphous silicon layer are that the ratio of H ₂ /SiH ₄ is 4-10, the deposition pressure is 0.3-0.5 mbar, the power density is 100-160 W/m ² , and the film thickness is 10-30 nm.

The substrate is glass, PI film, stainless steel or aluminum foil.

The transparent conductive front electrode layer is SnO ₂ :F, ZnO:B, ZnO:Al, Al/AZO or Al/Ag/GZO.

The back electrode layer is a transparent conductive oxide/metal composite film or a transparent conductive film ZnO:B.

The present invention also provides an amorphous silicon thin-film solar cell correspondingly, comprising a substrate, a transparent conductive front electrode layer, and a stacked battery layer comprising an amorphous silicon top cell and a conductive back electrode layer, the amorphous silicon top cell The intrinsic layer sequentially includes an amorphous silicon layer with a high hydrogen dilution ratio, a first amorphous silicon layer, a main body layer and a second amorphous silicon layer from the P layer to the N layer.

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

The method of the invention well solves the contradiction between cost and quality in the process of industrialization through simple deposition process control and combination optimization, that is, the contradiction between high-speed deposition and high-quality amorphous silicon material. The cell with this structure of the intrinsic layer of amorphous silicon has high photoelectric conversion efficiency and high light stability, and can obtain an amorphous silicon single-junction cell with a light-induced attenuation coefficient within 15% under the high-speed deposition condition of 4A/s And amorphous silicon/microcrystalline silicon laminated cells with a light-induced attenuation coefficient within 10%.

Description of drawings

The above and other objects, features and advantages of the present invention will be more apparent by a more specific description of preferred embodiments of the present invention shown in the accompanying drawings. The same reference numerals do not necessarily refer to the same parts throughout the drawings. The drawings have not been drawn to scale, emphasis instead being placed upon illustrating the gist of the invention. In the drawings, the thickness of layers are exaggerated for clarity.

Fig. 1 is the structural representation of the amorphous silicon thin-film solar cell illustrating the inventive method;

FIG. 2 is a schematic structural view of an amorphous silicon thin-film solar cell according to an embodiment of the present invention.

The illustrations are illustrative rather than restrictive, and the scope of protection of the invention should not be unduly limited here.

Detailed ways

In order to make the above objects, features and advantages of the present invention more comprehensible, specific implementations of the present invention will be described in detail below in conjunction with the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, the present invention can be implemented in many ways other than those described here, and those skilled in the art can make similar extensions without departing from the connotation of the present invention. Accordingly, the invention is not limited to the specific implementations disclosed below.

In order to solve the contradiction between low cost and high quality in the process of industrialization, that is, the contradiction between high-speed deposition and high-quality amorphous silicon material layer, the present invention proposes a four-step method for depositing an intrinsic layer of amorphous silicon . Experiments have found that for amorphous silicon materials, the main cause of light-induced attenuation is short-wavelength high-energy incident light, while long-wavelength low-energy incident light has relatively weak damage to the material. Short-wavelength sunlight is mainly absorbed in the P layer of the amorphous silicon top cell and the amorphous intrinsic layer close to the P layer. Therefore, the amorphous intrinsic layer near the P layer must have high quality and high light stability, while the quality of the amorphous silicon intrinsic layer in the main part can be appropriately reduced. The material of the intrinsic layer close to the N layer is also made of high-quality amorphous silicon layer, which has a dense structure and plays a good role in interface passivation. Therefore, the method of the present invention can greatly increase the deposition rate of the intrinsic layer of amorphous silicon and improve the production capacity of the equipment without substantially reducing the light stability of the amorphous silicon solar cell.

Intrinsic layer of amorphous silicon deposited by four-step method The first layer (close to the P layer) deposits an amorphous silicon layer with a high hydrogen dilution ratio; the second layer deposits a high-quality amorphous silicon layer; the third layer deposits the main layer, using high-speed The deposition method is prepared, and the deposition rate can be above 4A/s; the fourth layer deposits a high-quality amorphous silicon layer.

The manufacturing method of the amorphous silicon thin-film solar cell of the present invention first provides a substrate, deposits a transparent conductive front electrode layer on the surface of the substrate, and deposits a stacked battery layer including an amorphous silicon top layer battery on the surface of the transparent conductive front electrode layer , depositing a conductive back electrode layer on the surface of the laminate battery layer. Wherein, the intrinsic layer of the amorphous silicon top cell is deposited in four steps from the P layer to the N layer, and the first layer near the P layer is deposited with an amorphous silicon layer with a high hydrogen dilution ratio; the second layer is deposited with the first amorphous silicon layer. a crystalline silicon layer; the third layer deposits the main body layer, and the fourth layer deposits the second amorphous silicon layer.

Fig. 1 is a schematic diagram illustrating the structure of an amorphous silicon thin-film solar cell illustrating the method of the present invention. As shown in Figure 1, the manufacturing method of amorphous silicon thin film solar cell of the present invention at first deposits transparent conductive film 2 on glass, PI film substrate 1; 3. Intrinsic layer 4 of amorphous silicon (including an amorphous silicon layer 41 with a high hydrogen dilution ratio, a first amorphous silicon layer 42, a main body layer 43 and a second amorphous silicon layer 44); in the intrinsic layer of amorphous silicon An N-type conductive layer 5 is deposited on 4; an oxide/metal composite film 6 is deposited on the N-type conductive layer 5. Among them, the intrinsic layer 41 is an intrinsic layer of amorphous silicon with a high hydrogen dilution ratio, the deposition rate is 0.5-1A/s, and the thickness is 5-30nm; the intrinsic layer 42 is a high-quality amorphous silicon layer, and the deposition rate is 0.5 -2A/s, with a thickness of 20-60nm; the intrinsic layer 43 is a rapidly deposited amorphous silicon layer, and the deposition rate is above 3A/s; the intrinsic layer 44 is a high-quality amorphous silicon layer, and the deposition rate is 0.5- 2A/s, the thickness is 10-30nm.

Example 1: A 800nm SnO ₂ :F thin film 2 is deposited on a glass substrate 1 by CVD method as a transparent front electrode of a battery. On 2, P-type conductive a-SiC:H layer 3.1, amorphous silicon intrinsic layers 41, 42, 43 and 44 are sequentially prepared by plasma enhanced chemical vapor deposition (PECVD) of 15 nm; 4. A 20nm N-type conductive a-Si:H layer 5 is deposited on it; and an AZO/Al composite back electrode 6 is deposited on the N-type conductive layer 5. The deposition conditions of the amorphous silicon layer 41 are high hydrogen dilution ratio, H ₂ /SiH ₄ is 10, the deposition pressure is 0.3mbar, the power density is 210W/m ² , and the film thickness is 10nm; the deposition of the amorphous silicon layer 42 The condition is that H ₂ /SiH ₄ is 4, the deposition pressure is 0.3mbar, the power density is 132W/m ² , and the film thickness is 50nm; the amorphous silicon layer 43 is a high-speed deposition layer, the deposition rate is 4.5A/s, and the H ₂ /SiH ₄ is 1-4, the deposition pressure is 0.5mbar, the power density is 260W/m ² , the film thickness is 280nm; the amorphous silicon layer 44 is a high-quality amorphous silicon layer, and the deposition condition H ₂ /SiH ₄ is 4 , the deposition pressure is 0.5mbar, the power density is 130W/m ² , and the film thickness is 30nm. Compared with the solar cell with single-layer intrinsic layer structure deposited at a high speed of 4.5A/s, the light-induced attenuation coefficient of the amorphous silicon thin-film solar cell obtained under the three-layer structure has been improved by 15.8% (relative value), and after 1000 hours of light The light-induced attenuation coefficient is controlled within 16%.

Example 2: A 1500nm ZnO:B thin film 2 is deposited on a glass substrate 1 by LPCVD method as a transparent front electrode of a battery. On 2, P-type conductive a-SiC:H layer 3.1, amorphous silicon intrinsic layers 41, 42, 43 and 44 are sequentially prepared by plasma enhanced chemical vapor deposition (PECVD) of 15 nm; 4 Deposit 20nm N-type conductive a-Si:H layer 5 above; Deposit 1 μm thick microcrystalline silicon PIN bottom cell on N-type conductive layer 5; Then adopt LPCVD method to deposit 1600nm thick ZnO:B film back electrode 6 . The deposition conditions of the amorphous silicon layer 41 are high hydrogen dilution ratio, H ₂ /SiH ₄ is 10, the deposition pressure is 0.3mbar, the power density is 210W/m ² , and the film thickness is 10nm; the deposition of the amorphous silicon layer 42 The condition is that H ₂ /SiH ₄ is 4, the deposition pressure is 0.3mbar, the power density is 132W/m ² , and the film thickness is 40nm; the amorphous silicon layer 43 is a high-speed deposition layer, the deposition rate is 4.5A/s, and the H ₂ /SiH ₄ is 1-4, the deposition pressure is 0.5mbar, the power density is 260W/m ² , and the film thickness is 140nm; the amorphous silicon layer 44 is a high-quality amorphous silicon layer, and the deposition condition H ₂ /SiH ₄ is 4 , the deposition pressure is 0.5mbar, the power density is 130W/m ² , and the film thickness is 30nm. Compared with the 220nm-thick amorphous silicon intrinsic layer structure cell with a single layer deposited at a high speed of 4.5A/s, the light-induced attenuation coefficient of the amorphous silicon/microcrystalline silicon stacked thin film solar cell obtained under this three-layer structure is improved. 16.7% (relative value), and its light-induced attenuation coefficient after 1000 hours of light is controlled within 10%.

FIG. 2 is a schematic structural view of an amorphous silicon thin-film solar cell according to an embodiment of the present invention. As shown in Figure 2, an amorphous silicon thin-film solar cell according to an embodiment of the present invention includes a substrate 1, a transparent conductive front electrode layer 2, and a stacked battery layer including an amorphous silicon top layer cell and a conductive back electrode layer 9, wherein , the intrinsic layer 4 of the amorphous silicon top layer cell includes an amorphous silicon layer 41 with a high hydrogen dilution ratio, a first amorphous silicon layer 42, a main body layer 43 and a second amorphous silicon layer in sequence from the P layer 3 to the N layer 5 44. The stack cell layer also includes a microcrystalline silicon PIN bottom cell, which includes a p-layer 6 , an i-layer 7 and an n-layer 8 .

The above descriptions are only preferred embodiments of the present invention, and do not limit the present invention in any form. Any person familiar with the art, without departing from the scope of the technical solution of the present invention, can use the technical content disclosed above to make many possible changes and modifications to the technical solution of the present invention, or modify it into equivalent embodiments of equivalent changes . Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention that do not deviate from the technical solution of the present invention still belong to the protection scope of the technical solution of the present invention.

Claims (10)

1. A method for manufacturing an amorphous silicon thin-film solar cell, comprising steps: Provide the substrate; Depositing a transparent conductive front electrode layer on the surface of the substrate; Depositing a stacked cell layer comprising an amorphous silicon top layer cell on the surface of the transparent conductive front electrode layer; Depositing a conductive back electrode layer on the surface of the laminate battery layer; Wherein, the intrinsic layer of the amorphous silicon top cell is deposited in four steps from the P layer to the N layer, and the first layer near the P layer is deposited with an amorphous silicon layer with a high hydrogen dilution ratio; the second layer is deposited with the first amorphous silicon layer. a crystalline silicon layer; the third layer deposits the main body layer, and the fourth layer deposits the second amorphous silicon layer. 2. The method according to claim 1, characterized in that: the stacked battery layer comprises amorphous silicon PIN or NIP single-junction cells, amorphous silicon/microcrystalline silicon stacked cells, or amorphous silicon/amorphous Silicon germanium/microcrystalline silicon triple junction cells. 3. The method according to claim 1, characterized in that: the deposition condition of the amorphous silicon layer with a high hydrogen dilution ratio is a high hydrogen dilution ratio, H ₂ /SiH ₄ is 5-15, and the deposition pressure is 0.3- 0.5mbar, power density 180-280W/m ² , film thickness 5-30nm. 4. The method according to claim 1, characterized in that: the deposition conditions of the first amorphous silicon layer are: the ratio of H ₂ /SiH ₄ is 4-10, the deposition pressure is 0.3-0.5 mbar, and the power density 100-160W/m ² , and the film thickness is 20-60nm. 5. The method according to claim 1, characterized in that: the main body layer 4 is a high-speed deposition layer, the deposition rate is above 4A/s, the ratio of H ₂ /SiH ₄ is 1-4, and the deposition pressure is 0.4- 0.7mbar, power density 220-280W/m ² , film thickness 100-400nm. 6. The method according to claim 1, characterized in that: the deposition conditions of the second amorphous silicon layer are that the ratio of H ₂ /SiH ₄ is 4-10, the deposition pressure is 0.3-0.5 mbar, and the power density is 100- 160W/m ² , film thickness 10-30nm. 7. The method according to claim 1, wherein the substrate is glass, PI film, stainless steel or aluminum foil. 8 . The method according to claim 1 , wherein the transparent conductive front electrode layer is SnO ₂ :F, ZnO:B, ZnO:Al, Al/AZO or Al/Ag/GZO. 9. The method according to claim 1, characterized in that: the back electrode layer is a transparent conductive oxide/metal composite film or a transparent conductive film ZnO:B. 10. An amorphous silicon thin-film solar cell, comprising a substrate, a transparent conductive front electrode layer, and a stacked cell layer and a conductive back electrode layer comprising an amorphous silicon top cell, characterized in that: the amorphous silicon top cell The intrinsic layer sequentially includes an amorphous silicon layer with a high hydrogen dilution ratio, a first amorphous silicon layer, a main body layer and a second amorphous silicon layer from the P layer to the N layer.

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