阅读说明：本技术 一种非晶硅/微晶硅叠层太阳电池及其制造方法 (Amorphous silicon/microcrystalline silicon laminated solar cell and manufacturing method thereof ) 是由 靳果 王记昌 朱清智 郭闯 袁铸 申一歌 王慧 于 2020-05-05 设计创作，主要内容包括：本发明公开了一种非晶硅/微晶硅叠层太阳电池及其制造方法。按照制备顺序,该太阳电池结构依次由柔性透明衬底、前电极、非晶硅顶电池、连接层、微晶硅底电池、背电极组成。本发明利用连接层串联顶电池和底电池,可以优化子电池的光吸收比例,并且有利于光生载流子克服子电池界面处的反向势垒,从而在降低非晶硅顶电池厚度的情况下实现顶电池和底电池的短路电流密度相匹配,一方面提高太阳电池整体的短路电流密度,改善太阳电池的光电转换效率,另一方面减弱非晶硅顶电池的光致衰退效应,提高电池的稳定性。(The invention discloses an amorphous silicon/microcrystalline silicon laminated solar cell and a manufacturing method thereof. According to the preparation sequence, the solar cell structure sequentially comprises a flexible transparent substrate, a front electrode, an amorphous silicon top cell, a connecting layer, a microcrystalline silicon bottom cell and a back electrode. According to the invention, the connecting layer is connected in series with the top cell and the bottom cell, so that the light absorption ratio of the sub-cell can be optimized, and a photon-generated carrier is facilitated to overcome a reverse potential barrier at the interface of the sub-cell, so that the short-circuit current density of the top cell and the short-circuit current density of the bottom cell are matched under the condition of reducing the thickness of the amorphous silicon top cell, on one hand, the overall short-circuit current density of the solar cell is improved, the photoelectric conversion efficiency of the solar cell is improved, on the other hand, the light-induced degradation effect of the amorphous silicon top cell is.)

1. The amorphous silicon/microcrystalline silicon laminated solar cell is characterized by comprising a flexible transparent substrate (1), a front electrode (2), an amorphous silicon top cell (3), a connecting layer (4), a microcrystalline silicon bottom cell (5) and a back electrode (6) in sequence from the incident direction of light;

the flexible transparent substrate (1) is made of a flexible transparent polyimide film material;

the front electrode (2) is an aluminum-doped ZnO film;

the amorphous silicon top cell (3) is composed of a first p-type silicon thin film (7), a first intrinsic silicon thin film (8) and a first n-type silicon thin film (9) in sequence from the incident direction of light;

the connecting layer (4) is composed of a second n-type silicon thin film (10), a boron-doped ZnO thin film (11) and a second p-type silicon thin film (12) in sequence from the incident direction of light;

the microcrystalline silicon bottom cell (5) is composed of a third p-type silicon thin film (13), a second intrinsic silicon thin film (14) and a third n-type silicon thin film (15) in sequence from the incident direction of light;

the back electrode (6) is a metal Al film;

the first p-type silicon film is a p-type hydrogenated amorphous silicon carbon film;

the first intrinsic silicon film is an intrinsic hydrogenated amorphous silicon film;

the first n-type silicon film is an n-type hydrogenated amorphous silicon film;

the second p-type silicon film is a p-type hydrogenated microcrystalline silicon film;

the third p-type silicon film is a p-type hydrogenated microcrystalline silicon film;

the second intrinsic silicon film is an intrinsic hydrogenated microcrystalline silicon film;

the third n-type silicon film is an n-type hydrogenated amorphous silicon film;

the first n-type silicon film and the second n-type silicon film are formed by doping phosphorus elements in a plasma enhanced chemical vapor deposition process, and the second n-type silicon film is higher in doping concentration than the first n-type silicon film;

the second p-type silicon film and the third p-type silicon film are formed by doping boron elements in a plasma enhanced chemical vapor deposition process, and the second p-type silicon film is higher in doping concentration than the third p-type silicon film.

2. The method for manufacturing an amorphous silicon/microcrystalline silicon tandem solar cell according to claim 1, wherein: the preparation processes of the second n-type silicon film (10) and the first n-type silicon film (9) of the connecting layer are independent and are finished in different reaction chambers.

3. The method for manufacturing an amorphous silicon/microcrystalline silicon tandem solar cell according to claim 1, wherein: the boron-doped ZnO film (11) of the connecting layer is formed by reacting a raw material H₂O and Zn (C)₂H₅)₂Middle doped with B₂H₆And (4) obtaining.

4. The method for manufacturing an amorphous silicon/microcrystalline silicon tandem solar cell according to claim 1, wherein: the second p-type silicon film (12) and the third p-type silicon film (13) are continuously prepared by continuously supplying reaction raw materials in a single reaction chamber and obtaining two films by adjusting the concentration of reactants and the preparation time.

5. The method according to claim 1, wherein the first n-type silicon thin film has a thickness of 4 nm; the thickness of the third p-type silicon film is 3 nm.

6. The method as claimed in claim 1, wherein the amorphous silicon/microcrystalline silicon tandem solar cell is prepared byThe second n-type silicon film is an n-type hydrogenated microcrystalline silicon film with the thickness of 22nm and the doping concentration of 5.7 × 10¹⁸cm^-3The second p-type silicon film has a thickness of 19nm and a doping concentration of 1.0 × 10¹⁹cm^-3。

7. The method according to claim 1, wherein the boron-doped ZnO film has a thickness of 40nm and a doping concentration of 5.8 × 10¹⁹cm^-3。

8. The method for manufacturing an amorphous silicon/microcrystalline silicon tandem solar cell according to claim 1, wherein: the effective area of the laminated solar cell is 2.6cm²The thickness of the top cell is 275nm, the thickness of the bottom cell is 2680nm, the photoelectric conversion efficiency is 12.9%, and the light-induced degradation rate is within 7.5% in 1000 h.

9. A method for manufacturing an amorphous silicon/microcrystalline silicon tandem solar cell according to claims 1-8, wherein said method is implemented by a solar cell manufacturing system, said manufacturing system comprising: a cleaning system, a direct current-to-target magnetron sputtering system, a seven-chamber plasma chemical vapor deposition system, a metal organic chemical vapor deposition system and a metal thermal evaporation system;

the preparation method comprises the following steps:

cutting a flexible transparent polyimide film into a proper size, tightly arranging the flexible transparent polyimide film on a mould, putting the mould into a cleaning container, adding deionized water into the cleaning container, cleaning the container twice in an ultrasonic cleaning machine for 15 minutes each, taking out the container, drying the polyimide substrate and the mould by using a nitrogen gun, and putting the polyimide substrate and the mould into an oven for drying;

step two, the die is arranged in a direct current opposite target magnetron sputtering system to complete the preparation of the front electrode aluminum-doped ZnO film;

step three, the mould is arranged on a support of a wafer loading chamber of the plasma chemical vapor deposition system, and the mould is transferred into a p-type amorphous silicon material deposition chamber after the vacuum degree reaches the standard, so that the preparation of a first p-type silicon film of the top battery is completed;

pumping residual gas by using a vacuum pump, transferring the residual gas into an intrinsic amorphous silicon material deposition chamber after the vacuum degree reaches the standard, and completing the preparation of a first intrinsic silicon film of the top cell;

step five, pumping residual gas by using a vacuum pump, transferring the residual gas into an n-type amorphous silicon material deposition chamber after the vacuum degree reaches the standard, and completing the preparation of a first n-type silicon film of the top battery;

step six, pumping residual gas by using a vacuum pump, transferring the vacuum degree to an n-type microcrystalline silicon material deposition chamber after reaching the standard, and completing the preparation of a second n-type silicon film of the connecting layer;

step seven, taking out the die from the wafer loading chamber of the plasma chemical vapor deposition system, and putting the die into the metal organic chemical vapor deposition system to finish the preparation of the boron-doped ZnO film of the connecting layer;

step eight, taking out the die from the metal organic chemical vapor deposition system, placing the die on a bracket of a wafer loading chamber of the plasma chemical vapor deposition system, transferring the die into a p-type microcrystalline silicon material deposition chamber after the vacuum degree reaches the standard, and completing the preparation of a second p-type silicon film of the connecting layer;

step nine, adjusting the concentration of the reactant for continuous deposition to finish the preparation of a third p-type silicon film of the bottom cell;

step ten, pumping residual gas by using a vacuum pump, transferring the residual gas into an intrinsic type microcrystalline silicon material deposition chamber after the vacuum degree reaches the standard, and completing the preparation of a second intrinsic silicon film of the bottom cell;

step eleven, extracting residual gas by using a vacuum pump, transferring the residual gas into an n-type amorphous silicon material deposition chamber after the vacuum degree reaches the standard, and completing the preparation of a third n-type silicon film of the bottom cell;

and step twelve, taking the die out of the wafer loading chamber of the plasma chemical vapor deposition system, and putting the die into a metal thermal evaporation system to finish the preparation of the back electrode metal Al film.

Technical Field

The invention belongs to the technical field of photovoltaic power generation, and particularly relates to an amorphous silicon/microcrystalline silicon laminated solar cell and a manufacturing method thereof.

Background

The amorphous silicon/microcrystalline silicon (a-Si: H/muc-Si: H) laminated solar cell is formed by connecting an amorphous silicon top cell with an optical band gap of about 1.70eV and a microcrystalline silicon bottom cell with an optical band gap of about 1.10eV in series, and the laminated structure widens the spectral response range of the solar cell and improves the utilization rate of sunlight.

However, the performance of the tandem solar cell is not only related to the respective photoelectric conversion capabilities of the top and bottom cells, but also largely limited by the degree of current matching between the top and bottom cells, and the short-circuit current density of the entire tandem solar cell depends on the minimum sub-cell short-circuit current density. In addition, the amorphous silicon top cell can cause the whole photoelectric conversion performance of the laminated solar cell to decline along with the illumination time due to the light-induced decline phenomenon of the amorphous silicon material.

Therefore, the main technical problems faced by the amorphous silicon/microcrystalline silicon tandem solar cell include improving the matching degree of the short-circuit current density of the top cell and the bottom cell, improving the efficiency of the tandem solar cell, and reducing the thickness of the amorphous silicon top cell and improving the stability of the photoelectric conversion performance of the tandem solar cell.

Disclosure of Invention

Aiming at the main problems of the laminated solar cell, the invention provides a novel amorphous silicon/microcrystalline silicon laminated solar cell structure, wherein a top cell and a bottom cell are connected in series through a connecting layer, the reverse potential barrier effect at the interface of the top cell and the bottom cell is reduced, and the light absorption ratio of the top cell and the bottom cell is optimized, so that the thickness of the top cell is reduced, the short-circuit current density matching degree of the top cell and the bottom cell is improved, the laminated solar cell with high conversion efficiency and high stability is obtained, and most importantly, the optimal structure parameters of the connecting layer and the optimal thickness of the top cell and the bottom cell are obtained.

In order to achieve the above object, the present invention provides an amorphous silicon/microcrystalline silicon tandem solar cell, which is composed of, in order of preparation, a flexible transparent polyimide substrate, an aluminum-doped ZnO thin film, a first p-type silicon thin film, a first intrinsic silicon thin film, a first n-type silicon thin film, a second n-type silicon thin film, a boron-doped ZnO thin film, a second p-type silicon thin film, a third p-type silicon thin film, a second intrinsic silicon thin film, a third n-type silicon thin film, and a metallic Al thin film.

The invention relates to a method for manufacturing an amorphous silicon/microcrystalline silicon laminated solar cell, which comprises the following specific steps:

(1) substrate mounting and cleaning;

cutting a flexible transparent polyimide film into a proper size, tightly arranging the flexible transparent polyimide film on a mould, putting the mould into a cleaning container, adding deionized water, cleaning the container twice in an ultrasonic cleaning machine for 15 minutes each time, taking out the container, drying the polyimide substrate and the mould by using a nitrogen gun, and drying the polyimide substrate and the mould in an oven.

(2) Preparing a front electrode;

and (4) putting the die into a Direct Current (DC) twin-target magnetron sputtering system to finish the preparation of the front electrode aluminum-doped ZnO film.

(3) Preparing a first p-type silicon film;

and (3) placing the mold on a support of a wafer loading chamber of a plasma chemical vapor deposition system, transferring the mold to a p-type amorphous silicon material deposition chamber after the vacuum degree reaches the standard, and completing the preparation of the first p-type silicon film of the top battery.

(4) Preparing a first intrinsic silicon thin film;

and pumping residual gas by using a vacuum pump, transferring the residual gas into an intrinsic amorphous silicon material deposition chamber after the vacuum degree reaches the standard, and completing the preparation of the first intrinsic silicon film of the top cell.

(5) Preparing a first n-type silicon film;

and pumping residual gas by using a vacuum pump, transferring the vacuum degree to an n-type amorphous silicon material deposition chamber after reaching the standard, and completing the preparation of the first n-type silicon film of the top battery.

(6) Preparing a second n-type silicon film;

and pumping residual gas by using a vacuum pump, transferring the vacuum degree to an n-type microcrystalline silicon material deposition chamber after reaching the standard, and finishing the preparation of the second n-type silicon film of the connecting layer.

(7) Preparing a boron-doped ZnO film;

and taking out the die from the wafer loading chamber of the plasma chemical vapor deposition system, and putting the die into the metal organic chemical vapor deposition system to finish the preparation of the boron-doped ZnO film of the connecting layer.

(8) Preparing a second p-type silicon film;

and taking out the die from the metal organic chemical vapor deposition system, loading the die on a support of a wafer loading chamber of the plasma chemical vapor deposition system, transferring the die into a p-type microcrystalline silicon material deposition chamber after the vacuum degree reaches the standard, and completing the preparation of the second p-type silicon film of the connecting layer.

(9) Preparing a third p-type silicon film;

and adjusting the concentration of the reactant for continuous deposition to finish the preparation of the third p-type silicon film of the bottom cell.

(10) Preparing a second intrinsic silicon thin film;

and pumping residual gas by using a vacuum pump, transferring the residual gas into an intrinsic type microcrystalline silicon material deposition chamber after the vacuum degree reaches the standard, and completing the preparation of the second intrinsic silicon film of the bottom cell.

(11) Preparing a third n-type silicon film;

and pumping residual gas by using a vacuum pump, transferring the vacuum degree to an n-type amorphous silicon material deposition chamber after reaching the standard, and completing the preparation of a third n-type silicon film of the bottom battery.

(12) Preparing a metal Al film;

and taking the die out of a wafer loading chamber of the plasma chemical vapor deposition system, and putting the die into a metal thermal evaporation system to finish the preparation of the back electrode metal Al film.

Wherein the thickness of the first n-type silicon film is 4 nm;

the second n-type silicon film is an n-type hydrogenated microcrystalline silicon film with the thickness of 22nm and the doping concentration of 5.7 × 10¹⁸cm^-3；

The thickness of the boron-doped ZnO film is 40nm, and the doping concentration is 5.8 × 10¹⁹cm^-3；

The thickness of the second p-type silicon film is 19nm, and the doping concentration is 1.0 × 10¹⁹cm^-3；

The thickness of the third p-type silicon film is 3 nm;

the effective area of the solar cell is 2.6cm²The top cell thickness was 275nm and the bottom cell thickness was 2680 nm.

The invention adopts a novel amorphous silicon/microcrystalline silicon laminated solar cell structure, improves the problem of short-circuit current density mismatch of the top and bottom cells, improves the photoelectric conversion performance of the laminated solar cell, and has the conversion efficiency of 12.9 percent; the thickness of the amorphous silicon top cell is reduced to 275nm, the illumination stability of the laminated solar cell is improved, and the 1000-hour light-induced degradation rate is within 7.5%.

Drawings

Fig. 1 is a schematic structural diagram of an amorphous silicon/microcrystalline silicon tandem solar cell according to the present invention.

Detailed Description

In order to more clearly illustrate the technical problems, technical solutions and advantages solved by the present invention, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.