CN114447135B - Solar cell and preparation method thereof - Google Patents

Abstract

The application discloses a solar cell which comprises a microcrystalline silicon layer, a silicon dioxide layer, a silicon substrate layer, an intrinsic amorphous silicon layer and a doped amorphous silicon layer which are sequentially stacked from bottom to top. The application provides a solar cell and a preparation method thereof, wherein the back surface of a silicon substrate layer is passivated by adopting a SiO ₂ film, and doped amorphous silicon is induced to be crystallized into microcrystalline silicon with high doping concentration by adopting a method of inducing crystallization by adopting metals Al, au or Ag and the like which form a co-dissolved system with silicon; the intrinsic amorphous silicon may also be simultaneously p-doped and crystallized. The preparation method can effectively improve the doping efficiency of the film, thereby effectively improving the photoelectric conversion efficiency of the solar cell.

Description

A solar cell and a method for preparing the same

Technical Field

The present application relates to the technical field of solar cells, and in particular to a solar cell and a method for preparing the same.

Background Art

As PERC cells are getting closer to their efficiency limits, the entire photovoltaic industry has focused on high-efficiency solar cells such as heterojunctions. Currently, the highest efficiency achieved by heterojunction cells is 25.54%. However, due to the low effective doping of a-Si:H thin films in heterojunction cells, the built-in electric field of the PN junction and the contact resistance with TCO are large, resulting in limited photocurrent extraction, which greatly affects the FF and Jsc of solar cells.

Summary of the invention

In view of the above problems, the present application proposes a solar cell and a method for preparing the same, wherein the back of the silicon substrate layer is passivated with a _SiO2 thin film, and a method of inducing crystallization using metals such as Al, Au or Ag that form a symmetric system with silicon is used to convert the original p-type amorphous silicon (pa-Si:H) into p-type microcrystalline silicon (p-μc-Si:H), which can effectively improve the doping efficiency of the p-layer thin film, thereby effectively improving the photoelectric conversion efficiency of the solar cell. Intrinsic amorphous silicon (ia-Si:H) can also be p-doped and induced to crystallize at the same time to convert it into p-type microcrystalline silicon (p-μc-Si:H). N-type amorphous silicon (na-Si:H) can also be induced to crystallize and converted into n-type microcrystalline silicon (n-μc-Si:H).

The present application provides a solar cell, comprising a microcrystalline silicon layer, a silicon dioxide layer, a silicon base layer, an intrinsic amorphous silicon layer and a doped amorphous silicon layer which are sequentially stacked from bottom to top.

Furthermore, the silicon base layer is n-type crystalline silicon or p-type crystalline silicon, preferably n-type crystalline silicon.

Furthermore, the microcrystalline silicon layer is a p-type microcrystalline silicon layer or an n-type microcrystalline silicon layer, and preferably has a thickness of 5-30 nm.

Furthermore, the doped amorphous silicon layer is an n-type amorphous silicon layer or a p-type amorphous silicon layer, and preferably has a thickness of 5-15 nm.

Furthermore, the thickness of the silicon dioxide layer is 0.5-2 nm.

Furthermore, a second transparent conductive layer is arranged on the surface of the microcrystalline silicon layer on the side away from the silicon dioxide layer, and a first transparent conductive layer is arranged on the surface of the amorphous silicon layer on the side away from the intrinsic amorphous silicon layer; a first metal electrode is arranged on the surface of the first transparent conductive layer on the side away from the amorphous silicon layer, and a second metal electrode is arranged on the surface of the second transparent conductive layer on the side away from the microcrystalline silicon layer.

The present application provides a method for preparing a solar cell, comprising the following steps:

providing a silicon base layer;

Depositing a silicon dioxide layer on one side surface of the silicon base layer;

Depositing an amorphous silicon layer to be crystallized on a side of the silicon dioxide layer away from the silicon base layer;

Depositing a metal film on the surface of the amorphous silicon to be crystallized away from the silicon dioxide layer, and then annealing, so that the amorphous silicon layer to be crystallized is converted into a microcrystalline silicon layer;

Depositing an intrinsic amorphous silicon layer on a surface of the silicon base layer facing away from the silicon dioxide layer;

A doped amorphous silicon layer is deposited on a surface of the intrinsic amorphous silicon layer facing away from the silicon base layer.

Furthermore, the metal film is selected from one or more of aluminum film, gold film or silver film.

Furthermore, the metal film is deposited on the amorphous silicon layer by evaporation or magnetron sputtering, and then annealed under nitrogen protection. Preferably, the annealing temperature is 300-500° C., and more preferably, the annealing time is 1-3 hours.

Furthermore, the thickness of the metal film is 10-20 nm.

Furthermore, after the annealing is completed, an acidic cleaning solution is used to wash away the metal remaining on the surface of the microcrystalline silicon layer.

Furthermore, the solar cell is the aforementioned solar cell.

The solar cell provided by the present application is characterized in that the back of the silicon substrate layer is passivated by a silicon dioxide layer, and a method of inducing crystallization by using metals such as Al, Au or Ag that form a symmetric system with silicon is used to convert the original p-type amorphous silicon (p-a-Si:H) layer into a p-type microcrystalline silicon (p-μc-Si:H) layer, which can effectively improve the doping efficiency of the p-microcrystalline silicon layer, thereby effectively improving the photoelectric conversion efficiency of the solar cell; and the n-type amorphous silicon (n-a-Si:H) layer can also be converted into an n-type microcrystalline silicon (n-μc-Si:H) layer. In addition, metal Al forms a symmetric system with silicon and simultaneously performs p-type doping and induces crystallization to convert the intrinsic amorphous silicon (i-a-Si:H) layer into a p-type microcrystalline silicon (p-μc-Si:H) layer.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are used to better understand the present application and do not constitute an improper limitation on the present application.

FIG1 is a schematic diagram of the structure of a solar cell provided by the present application;

FIG. 2 is a schematic diagram of the structure of a solar cell provided in a comparative example of the present application.

Description of Reference Numerals

1-first metal electrode, 2-first transparent conductive layer, 3-n-type amorphous silicon layer, 4-first intrinsic amorphous silicon layer, 5-silicon base layer, 6-silicon dioxide layer, 6'-second intrinsic amorphous silicon layer, 7-p-type microcrystalline silicon layer, 8-second transparent conductive layer, 9-second metal electrode.

DETAILED DESCRIPTION

The following is a description of exemplary embodiments of the present application, including various details of the embodiments of the present application to facilitate understanding, which should be considered as merely exemplary. Therefore, it should be recognized by those of ordinary skill in the art that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the present application. Similarly, for clarity and conciseness, the description of well-known functions and structures is omitted in the following description. In the present application, the upper and lower positions are determined according to the incident direction of the light, and the place where the light is incident is the upper part.

The present application provides a solar cell, comprising a microcrystalline silicon layer, a silicon dioxide layer, a silicon base layer, an intrinsic amorphous silicon layer and an amorphous silicon layer which are sequentially stacked from bottom to top.

Specifically, the silicon base layer is n-type crystalline silicon or p-type crystalline silicon, preferably n-type crystalline silicon, for example, n-type single crystal silicon or n-type polycrystalline silicon.

Specifically, the microcrystalline silicon layer is a p-type microcrystalline silicon layer or an n-type microcrystalline silicon layer, and has a thickness of 5-30 nm, for example, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 11 nm, 12 nm, 13 nm, 14 nm, 15 nm, 16 nm, 17 nm, 18 nm, 19 nm, 20 nm, 21 nm, 22 nm, 23 nm, 24 nm, 25 nm, 26 nm, 27 nm, 28 nm, 29 nm or 30 nm.

Specifically, the amorphous silicon layer may be an n-type amorphous silicon layer, a p-type amorphous silicon layer, or an intrinsic amorphous silicon layer, and its thickness is 5-15 nm, for example, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 11 nm, 12 nm, 13 nm, 14 nm, or 15 nm.

Specifically, the thickness of the silicon dioxide layer is 0.5-2 nm, for example, it can be 0.5 nm, 0.6 nm, 0.7 nm, 0.8 nm, 0.9 nm, 1 nm, 1.1 nm, 1.2 nm, 1.3 nm, 1.4 nm, 1.5 nm, 1.6 nm, 1.7 nm, 1.8 nm, 1.9 nm or 2 nm.

The silicon dioxide layer can serve as both a passivation layer and a barrier layer.

Specifically, as shown in FIG1 , the solar cell includes a second transparent conductive layer, a p-type microcrystalline silicon layer, a silicon dioxide layer, a silicon base layer, an intrinsic amorphous silicon layer (a first intrinsic amorphous silicon layer), an n-type amorphous silicon layer, and a first transparent conductive layer stacked in sequence from bottom to top. A first metal electrode is disposed on a surface of the first transparent conductive layer facing away from the n-type amorphous silicon layer, and a second metal electrode is disposed on a surface of the second transparent conductive layer facing away from the p-type microcrystalline silicon layer.

The thickness of the first transparent conductive layer and the second transparent conductive layer may be 70-100 nm, for example, 70 nm, 75 nm, 80 nm, 85 nm, 90 nm, 95 nm or 100 nm.

The first metal electrode and the second metal electrode can both be aluminum electrodes or silver electrodes.

The present application also provides a method for preparing a solar cell, comprising the following steps:

Step 1: providing a silicon base layer;

Step 2: depositing a silicon dioxide layer on one side of the silicon substrate layer;

Step 3: depositing an amorphous silicon layer on a side of the silicon dioxide layer away from the silicon base layer;

Step 4: depositing a metal film on a surface of the amorphous silicon layer facing away from the silicon dioxide layer, and then annealing the amorphous silicon layer to transform the amorphous silicon layer into a microcrystalline silicon layer;

Step 5: depositing an intrinsic amorphous silicon layer on a surface of the silicon base layer facing away from the silicon dioxide layer;

Step six: depositing an amorphous silicon layer on the surface of the intrinsic amorphous silicon layer on a side away from the silicon base layer.

In step one, the surface of the silicon wafer is textured and cleaned to form a silicon base layer.

Specifically, the silicon wafer is first textured with alkali solution and a texturing additive, and then the surface of the silicon wafer is cleaned using the RCA standard cleaning method (a commonly used wet chemical cleaning method proposed by the RCA laboratory in Princeton, New Jersey, USA in 1965) to remove surface contaminants. Finally, a 1% hydrofluoric acid solution is used to remove the surface oxide layer.

The silicon wafer is an n-type double-sided polished CZ single crystal silicon wafer with a thickness of 150-300 μm, a resistivity of 0.1-5 Ω·cm, and a minority carrier lifetime greater than 1000 μs.

In step 2, a silicon dioxide layer is deposited on one side of the silicon base layer by thermal oxidation.

In step four, the metal film is deposited on the amorphous silicon layer by evaporation or magnetron sputtering, and then annealed under nitrogen protection. The annealing temperature is 300-500°C and the annealing time is 1-3h. After the annealing, an acidic washing solution (the acidic washing solution can be an HCl solution) is used to wash away the metal remaining on the surface of the microcrystalline silicon layer.

The silicon dioxide layer can block metal from entering the silicon base layer, and the silicon dioxide layer can also passivate the silicon base layer.

The metal film is selected from one or more of aluminum film, gold film or silver film.

The thickness of the metal film is 10-20 nm, for example, 10 nm, 12 nm, 14 nm, 16 nm, 18 nm or 20 nm.

The method further comprises:

Step seven: depositing a first transparent conductive layer and a second transparent conductive layer on a surface of the amorphous silicon layer facing away from the intrinsic amorphous silicon layer and on a surface of the microcrystalline silicon layer facing away from the silicon dioxide layer.

Step eight: depositing a first metal electrode and a second metal electrode on the first transparent conductive layer and the second transparent conductive layer respectively.

The present application also provides a method for preparing a solar cell, comprising the following steps:

Step 1: providing a silicon base layer;

Specifically, the surface of the silicon wafer is textured and cleaned to form a silicon base layer.

Specifically, the silicon wafer is first textured with alkali solution and a texturing additive, and then the surface of the silicon wafer is cleaned using the RCA standard cleaning method (a commonly used wet chemical cleaning method proposed by the RCA laboratory in Princeton, New Jersey, USA in 1965) to remove surface contaminants. Finally, a 1% hydrofluoric acid solution is used to remove the surface oxide layer.

The silicon wafer is an n-type double-sided polished CZ single crystal silicon wafer with a thickness of 150-300 μm, a resistivity of 0.1-5 Ω·cm, and a minority carrier lifetime greater than 1000 μs.

Step 2: depositing a silicon dioxide layer on one side of the silicon substrate layer;

Specifically, a silicon dioxide layer is deposited on one side surface of the silicon base layer by a thermal oxidation method.

Step 3: depositing an amorphous silicon layer to be crystallized on a side of the silicon dioxide layer away from the silicon base layer;

Step 4: depositing a metal film on the surface of the amorphous silicon layer on the side away from the silicon dioxide layer, and then annealing, so that the amorphous silicon layer to be crystallized is converted into a microcrystalline silicon layer;

Specifically, the metal film is deposited on the amorphous silicon layer by evaporation or magnetron sputtering, and then annealed under nitrogen protection, the annealing temperature is 300-500°C, the annealing time is 1-3h, and after the annealing, the metal remaining on the surface of the microcrystalline silicon layer is washed away with an acidic washing solution (the acidic washing solution can be an HCl solution).

The silicon dioxide layer can block metal from entering the silicon base layer, and the silicon dioxide layer can also passivate the silicon base layer.

The metal film is selected from one or more of aluminum film, gold film or silver film.

The thickness of the metal film is 10-20 nm, for example, 10 nm, 12 nm, 14 nm, 16 nm, 18 nm or 20 nm.

Step 5: depositing an intrinsic amorphous silicon layer on a surface of the silicon base layer facing away from the silicon dioxide layer;

Step six: depositing a doped amorphous silicon layer on a surface of the intrinsic amorphous silicon layer facing away from the silicon base layer.

Step seven: depositing a first transparent conductive layer and a second transparent conductive layer on a surface of the doped amorphous silicon layer away from the intrinsic amorphous silicon layer and on a surface of the microcrystalline silicon layer away from the silicon dioxide layer.

Step eight: depositing a first metal electrode and a second metal electrode on the first transparent conductive layer and the second transparent conductive layer respectively.

Example

The experimental methods used in the following examples are all conventional methods unless otherwise specified.

Unless otherwise specified, the materials and reagents used in the following examples can be obtained from commercial sources.

Example 1

The solar cell of this embodiment, its preparation method comprises the following steps:

Step 1: First, use a 2% KOH and IPA mixed solution to texturize an n-type crystalline silicon wafer (n-type double-sided polished CZ single crystal silicon wafer, with a thickness of 150μm, a resistivity of 0.3Ω·cm, and a minority carrier lifetime of 1000μs) at 83°C. Then, use the RCA standard cleaning method to clean the surface of the n-type crystalline silicon wafer to remove surface contaminants. Finally, use a 1% hydrofluoric acid solution to remove the surface oxide layer to obtain a silicon base layer 5.

Step 2: A 1.2 nm thick silicon dioxide layer 6 is grown on one side of the silicon substrate layer by thermal oxidation, the reaction gas is O ₂ , the pressure is 200 Pa, and the substrate temperature is 950°C.

Step 3: Deposit a p-type boron-doped amorphous silicon layer with a thickness of 25 nm on the surface of the silicon dioxide layer 6 facing away from the silicon base layer 5. The reaction gases are SiH ₄ , H ₂ and B ₂ H ₆ , H ₂ /SiH ₄ = 10, B ₂ H ₆ /SiH ₄ = 0.02. The power density is 0.027 W/cm ² , the pressure is 80 Pa, and the substrate temperature is 200°C.

Step 4: using an evaporation method, using high-purity Al (6N), and a heating current of 15A, a 15nm thick metal Al film is deposited on the surface of the p-type boron-doped amorphous silicon layer away from the silicon dioxide layer 6 .

Step 5: The product obtained in step 4 is annealed under nitrogen protection at a temperature of 500°C for 1 hour to make the p-type boron-doped amorphous silicon layer undergo a phase change and transform into a p-type boron-doped microcrystalline silicon layer. Then, the residual metal Al on the surface is cleaned with HCl solution.

Step 6: Deposit a first intrinsic amorphous silicon layer 4 with a thickness of 7 nm on the surface of the silicon base layer away from the silicon dioxide layer 6 by PECVD method, the reaction gases are _SiH4 and _H2 , wherein _H2 / _SiH4 =5, the power density is 0.020W/ ^cm2 , the pressure is 100Pa, and the substrate temperature is 200℃.

Step 7: On the surface of the first intrinsic amorphous silicon layer 4 facing away from the silicon base layer, a 10 nm n-type phosphorus-doped amorphous silicon layer is deposited by a PECVD method, the reaction gases are SiH ₄ , H ₂ and PH ₃ , H ₂ /SiH ₄ =10, PH ₃ /SiH ₄ =0.03, the power density of the power supply is 0.13 W/cm ² , the pressure is 200 Pa, and the substrate temperature is 200°C.

Step eight: filling with Ar and O ₂ , O ₂ /Ar=0.025, pressure 0.5 Pa, substrate temperature is room temperature, and depositing a first transparent conductive layer (ITO (In: Sn=90:10)) 2 and a second transparent conductive layer (ITO (In: Sn=90:10)) 8 with a thickness of 75 nm on the surface of the n-type phosphorus-doped amorphous silicon layer away from the first intrinsic amorphous silicon layer 4 and on the p-type boron-doped microcrystalline silicon layer away from the silicon dioxide layer 6.

Step nine: silver electrodes 1 and 9 are screen-printed on the first transparent conductive layer and the second transparent conductive layer.

The performance of the solar cell of this embodiment is shown in Table 1 and Table 2.

Example 2

The solar cell of this embodiment, its preparation method comprises the following steps:

Step 1: First, use a 2% KOH and IPA mixed solution to texturize an n-type crystalline silicon wafer (n-type double-sided polished CZ single crystal silicon wafer, with a thickness of 150μm, a resistivity of 0.3Ω·cm, and a minority carrier lifetime of 1000μs) at 83°C. Then, use the RCA standard cleaning method to clean the surface of the n-type crystalline silicon wafer to remove surface contaminants. Finally, use a 1% hydrofluoric acid solution to remove the surface oxide layer to obtain a silicon base layer 5.

Step 2: A 1.2 nm thick silicon dioxide layer 6 is grown on one side of the silicon substrate layer by thermal oxidation, the reaction gas is O ₂ , the pressure is 200 Pa, and the substrate temperature is 950°C.

Step 3: depositing an intrinsic amorphous silicon layer with a thickness of 25 nm on the surface of the silicon dioxide layer 6 facing away from the silicon base layer 5, with the reaction gases being SiH ₄ and H ₂ , H ₂ /SiH ₄ = 10, the power density being 0.027 W/cm ² , the pressure being 80 Pa, and the substrate temperature being 200°C.

Step 4: using an evaporation method, using high-purity Al (6N), and a heating current of 15A to deposit a 18 nm thick metal Al film on the surface of the intrinsic amorphous silicon layer away from the silicon dioxide layer 6 .

Step 5: The product obtained in step 4 is annealed under nitrogen protection at a temperature of 500°C for 1 hour to allow the intrinsic amorphous silicon layer to undergo Al doping and phase transition and be converted into a p-type aluminum-doped microcrystalline silicon layer. The residual metal Al on the surface is then cleaned with HCl solution.

Step 6: Deposit a first intrinsic amorphous silicon layer 4 with a thickness of 7 nm on the surface of the silicon base layer away from the silicon dioxide layer 6 by PECVD method, the reaction gases are _SiH4 and _H2 , wherein _H2 / _SiH4 =5, the power density is 0.020W/ ^cm2 , the pressure is 100Pa, and the substrate temperature is 200℃.

Step 7: On the surface of the first intrinsic amorphous silicon layer 4 facing away from the silicon base layer 5, a 10 nm n-type phosphorus-doped amorphous silicon layer is deposited by a PECVD method, the reaction gases are SiH ₄ , H ₂ and PH ₃ , H ₂ /SiH ₄ =10, PH ₃ /SiH ₄ =0.03, the power density of the power supply is 0.13 W/cm ² , the pressure is 200 Pa, and the substrate temperature is 200°C.

Step eight: filling with Ar and O ₂ , O ₂ /Ar=0.025, pressure 0.5 Pa, substrate temperature is room temperature, and depositing a first transparent conductive layer (ITO (In: Sn=90:10)) 2 and a second transparent conductive layer (ITO (In: Sn=90:10)) 8 with a thickness of 75 nm on the surface of the n-type phosphorus-doped amorphous silicon layer away from the first intrinsic amorphous silicon layer 4 and on the p-type aluminum-doped microcrystalline silicon layer 7 away from the silicon dioxide layer 6.

Step nine: silver electrodes 1 and 9 are printed on the first transparent conductive layer 8 and the second transparent conductive layer 2 by screen printing.

The solar cell of this embodiment is shown in Table 1.

Comparative Example 1

The solar cell of this embodiment, as shown in FIG2 , has a preparation method comprising the following steps:

Step 1: First, use a 2% KOH and IPA mixed solution to texturize an n-type crystalline silicon wafer 5 (n-type double-sided polished CZ single crystal silicon wafer, with a thickness of 150 μm, a resistivity of 0.3 Ω·cm, and a minority carrier lifetime of 1000 μs) at a temperature of 83°C. Then, use the RCA standard cleaning method to clean the surface of the n-type crystalline silicon wafer to remove surface contaminants. Finally, use a 1% hydrofluoric acid solution to remove the surface oxide layer to obtain a silicon base layer.

Step 2: Deposit a second intrinsic amorphous silicon layer 6' with a thickness of 10 nm on one side surface of the silicon substrate layer by PECVD method, the reaction gases are _SiH4 and _H2 , wherein _H2 / _SiH4 =5, the power density is 0.020W/ ^cm2 , the pressure is 100Pa, and the substrate temperature is 200℃.

Step 3: deposit a p-type boron-doped amorphous silicon layer with a thickness of 10 nm on the surface of the second intrinsic amorphous silicon layer 6' away from the silicon base layer 5, the reaction gas is _SiH4 , _H2 and _B2H6 , _H2 / _SiH4 = ₁₀ , _B2H6 / _SiH4 = 0.02. The power density is 0.027W/ ^cm2 , the pressure is 80Pa, _and the substrate temperature is 200℃.

Step 4: Deposit a first intrinsic amorphous silicon layer 4 with a thickness of 7 nm on the surface of the silicon base layer away from the second intrinsic amorphous silicon layer 6' by PECVD method, the reaction gases are _SiH4 and _H2 , wherein _H2 / _SiH4 =5, the power density is 0.020W/ ^cm2 , the pressure is 100Pa, and the substrate temperature is 200℃.

Step 5: On the surface of the first intrinsic amorphous silicon layer 4 facing away from the silicon base layer, a 10 nm n-type phosphorus-doped amorphous silicon layer is deposited by a PECVD method, the reaction gases are SiH ₄ , H ₂ and PH ₃ , H ₂ /SiH ₄ =10, PH ₃ /SiH ₄ =0.03, the power density of the power supply is 0.13 W/cm ² , the pressure is 200 Pa, and the substrate temperature is 200°C.

Step 6: Filling with Ar and O ₂ , O ₂ /Ar=0.025, pressure 0.5 Pa, substrate temperature is room temperature, depositing a first transparent conductive layer (ITO (In: Sn=90:10)) 2 and a second transparent conductive layer (ITO (In: Sn=90:10)) 8 with a thickness of 75 nm on the surface of the n-type phosphorus-doped amorphous silicon layer 3 away from the first intrinsic amorphous silicon layer 4 and on the surface of the p-type boron-doped amorphous silicon layer away from the second intrinsic amorphous silicon layer 6 '.

Step seven: silver electrodes 1 and 9 are screen-printed on the first transparent conductive layer and the second transparent conductive layer.

The performance of the solar cell of this embodiment is shown in Table 1 and Table 2.

Comparative Example 2

The difference between Comparative Example 2 and Example 1 is that the p-type boron-doped microcrystalline silicon layer is prepared by directly forming the p-type boron-doped microcrystalline silicon layer on the silicon dioxide layer using the PECVD method in Comparative Example 2. The solar cell performance of this comparative example is shown in Tables 1 and 2.

Table 1

Table 2 shows the performance parameters of each embodiment and comparative example.

Average Eff/% Average Voc/mV Average Jsc/mA/ ^cm2 Average FF/% Dark conductivity S/cm Crystalline ratio% Example 1 24.17 741.2 39.3 83.4 1E0-1E2 50%-70% Example 2 23.94 740.5 39.2 82.5 1E0-1E2 50%-70% Comparative Example 1 23.43 739 39.1 81.1 1E(-4)-1E(-2) 0% Comparative Example 2 23.84 740 39.2 82.2 1E(-2)-1E0 20%-40%

Summary: This application adopts a silicon dioxide back passivation process to ensure the passivation stability of the heterojunction interface. Secondly, a metal Al film-induced preparation method of a p-type microcrystalline silicon layer is adopted to prepare a hybrid heterojunction battery integrating Topcon technology. This not only ensures good passivation of the c-Si interface, but also prepares a p-type microcrystalline silicon layer with a high doping degree and a high crystallinity ratio. While ensuring that the interface passivation is intact, the doping concentration of the p-type microcrystalline silicon layer is effectively increased, which can effectively improve the battery efficiency.

Although the embodiments of the present application are described above, the present application is not limited to the above specific embodiments and application fields, and the above specific embodiments are merely illustrative and instructive, rather than restrictive. A person of ordinary skill in the art can make many forms under the guidance of this specification and without departing from the scope of protection of the claims of the present application, all of which belong to the protection of the present application.

Claims (12)

1. A solar cell, characterized in that it comprises a microcrystalline silicon layer, a silicon dioxide layer, a silicon base layer, an intrinsic amorphous silicon layer and a doped amorphous silicon layer stacked in sequence from bottom to top; The method for preparing the solar cell comprises the following steps: providing a silicon base layer; Depositing a silicon dioxide layer on one side surface of the silicon base layer; Depositing an amorphous silicon layer to be crystallized on a side of the silicon dioxide layer away from the silicon base layer; Depositing a metal film on a surface of the amorphous silicon layer to be crystallized away from the silicon dioxide layer, and then annealing the amorphous silicon layer to be crystallized to transform it into a microcrystalline silicon layer; Depositing an intrinsic amorphous silicon layer on a surface of the silicon base layer facing away from the silicon dioxide layer; Depositing a doped amorphous silicon layer on a surface of the intrinsic amorphous silicon layer facing away from the silicon base layer; The metal film is deposited on the amorphous silicon layer to be crystallized by evaporation or magnetron sputtering, and then annealed at a temperature of 300-500°C. 2 . The solar cell according to claim 1 , wherein the silicon substrate layer is n-type crystalline silicon or p-type crystalline silicon. 3 . The solar cell according to claim 1 , wherein the microcrystalline silicon layer is a p-type microcrystalline silicon layer or an n-type microcrystalline silicon layer, and has a thickness of 5-30 nm. 4 . The solar cell according to claim 1 , wherein the doped amorphous silicon layer is an n-type amorphous silicon layer or a p-type amorphous silicon layer, and has a thickness of 5-15 nm. 5 . The solar cell according to claim 1 , wherein the thickness of the silicon dioxide layer is 0.5-2 nm. 6. The solar cell according to claim 1 is characterized in that a second transparent conductive layer is arranged on a surface of the microcrystalline silicon layer on a side away from the silicon dioxide layer, and a first transparent conductive layer is arranged on a surface of the doped amorphous silicon layer on a side away from the intrinsic amorphous silicon layer; a first metal electrode is arranged on a surface of the first transparent conductive layer on a side away from the doped amorphous silicon layer, and a second metal electrode is arranged on a surface of the second transparent conductive layer on a side away from the microcrystalline silicon layer. 7. A method for preparing a solar cell, characterized in that it comprises the following steps: providing a silicon base layer; Depositing a silicon dioxide layer on one side surface of the silicon base layer; Depositing an amorphous silicon layer to be crystallized on a side of the silicon dioxide layer away from the silicon base layer; Depositing a metal film on a surface of the amorphous silicon layer to be crystallized away from the silicon dioxide layer, and then annealing the amorphous silicon layer to be crystallized to transform it into a microcrystalline silicon layer; Depositing an intrinsic amorphous silicon layer on a surface of the silicon base layer facing away from the silicon dioxide layer; Depositing a doped amorphous silicon layer on a surface of the intrinsic amorphous silicon layer facing away from the silicon base layer; The metal film is deposited on the amorphous silicon layer to be crystallized by evaporation or magnetron sputtering, and then annealed at a temperature of 300-500°C. 8 . The preparation method according to claim 7 , wherein the amorphous silicon layer to be crystallized is an intrinsic amorphous silicon layer, an n-type amorphous silicon layer or a p-type amorphous silicon layer. 9 . The preparation method according to claim 7 , wherein the metal film is selected from one or more of aluminum film, gold film or silver film. 10. The preparation method according to claim 7, characterized in that annealing is performed under nitrogen protection, the annealing time is 1-3 hours, and the thickness of the metal film is 10-20 nm. 11 . The preparation method according to claim 7 , characterized in that after the annealing is completed, an acidic washing solution is used to wash away the metal remaining on the surface of the microcrystalline silicon layer. 12. The preparation method according to any one of claims 7 to 11, characterized in that the solar cell is the solar cell according to any one of claims 1 to 6.