A high-performance passivation film for heterojunction solar cells and a preparation method thereof

Abstract

The present invention relates to the technical field of solar cells, and in particular to a high-performance passivation film for heterojunction solar cells and a preparation method thereof, comprising the following steps: depositing five layers of silicon-based films and hydrogen treatment layers on a textured silicon substrate in sequence, wherein the five layers of silicon-based films are an interface anti-epitaxial layer, a transition layer, a wide-bandgap transition layer, a wide-bandgap dense layer and a dense barrier layer in sequence. The multi-layer arrangement and thickness ratio in the passivation film of the invention can ensure the stability of the series resistance and fill factor of the battery terminal.

Description

Technical Field

[0001] The invention relates to the technical field of solar cells, and in particular to a high-performance passivation film for a heterojunction solar cell and a preparation method thereof. Background Art

[0002] At present, heterojunction solar cells face two more severe challenges: 1. Due to the unique high passivation requirements of heterojunction solar cells, the intrinsic amorphous silicon layer on the front is a hydrogen-rich film. The atomic arrangement in this amorphous silicon film is relatively loose, and there are many structural defects, such as hanging chains and voids. These defects can act as impurities and defect centers. When light passes through the amorphous silicon film, part of the light energy will be absorbed by these defect centers, resulting in energy loss, thereby reducing the photoelectric conversion efficiency of the solar cell. 2. Since the front of the heterojunction solar cell is an ITO transparent conductive film, a microcrystalline N layer, and an intrinsic amorphous silicon layer. The front ITO transparent conductive film and microcrystalline N layer cannot completely block ultraviolet light. More than 70% of ultraviolet light passes through the front ITO transparent conductive film and microcrystalline N layer to reach the intrinsic amorphous silicon layer, and the ultraviolet light energy can just destroy the Si-H2 bond, resulting in hydrogen loss and reducing the passivation effect. At present, this effect can only be isolated by using an ultraviolet cutoff film or an ultraviolet conversion film at the component end. Summary of the invention

[0003] The purpose of the present invention is to provide a high-performance passivation film for heterojunction solar cells and a preparation method thereof, so as to solve the technical problem in the prior art that the Si-H2 groups in the intrinsic amorphous silicon layer located on the front side of the cell are easily destroyed by ultraviolet light, resulting in large attenuation.

[0004] The present invention discloses a method for preparing a high-performance passivation film for a heterojunction solar cell, comprising the following steps:

[0005] Five silicon-based films and hydrogen-treated layers are sequentially deposited on the textured silicon substrate, wherein the five silicon-based films are sequentially an interface anti-epitaxial layer, a transition layer, a wide-bandgap transition layer, a wide-bandgap dense layer and a dense barrier layer.

[0006] Furthermore, the interface anti-epitaxial layer uses carbon dioxide and silane as source gases.

[0007] Furthermore, when the interface anti-epitaxial layer is deposited, the silane flow rate ranges from 1000 to 2000 sccm, and the carbon dioxide doping concentration ranges from 10% to 20%.

[0008] Furthermore, during the deposition of the interface anti-epitaxial layer, the pressure in the deposition chamber is in the range of 50Pa to 110Pa, the temperature is in the range of 165-185°C, and the power density of the RF power source is in the range of 0.02-0.03W / cm 2The plasma action time is 2-3S and its thickness should be 0.5-1nm.

[0009] By setting an interface anti-epitaxial layer, the epitaxial growth of crystalline silicon can be prevented, the generation of more dangling bonds can be prevented, and the defect state density can be prevented from further increasing.

[0010] Furthermore, the transition layer uses pure silane as source gas.

[0011] Furthermore, the silane flow rate ranges from 800 to 1600 sccm during the deposition of the transition layer.

[0012] Furthermore, during the deposition of the transition layer, the pressure in the deposition chamber is in the range of 30 Pa to 60 Pa, the temperature is in the range of 165-185° C., and the power density of the RF power source is in the range of 0.01-0.015 W / cm 2 The plasma action time is 4-6S and its thickness should be 1-1.5nm.

[0013] By setting a transition layer with a high hydrogen content, the high-density dangling bonds at the interface are passivated by the high hydrogen content, thereby reducing the surface state density, lowering the surface recombination rate, and increasing the carrier lifespan.

[0014] Furthermore, the wide bandgap transition layer uses silane and carbon dioxide as source gases.

[0015] Furthermore, when the wide bandgap transition layer is deposited, the silane flow rate ranges from 800 to 1600 sccm, and the carbon dioxide doping concentration ranges from 30% to 40%.

[0016] Furthermore, when the wide bandgap transition layer is deposited, the pressure in the deposition chamber is in the range of 30Pa to 60Pa, the temperature is in the range of 165-185°C, and the power density of the RF power source is in the range of 0.01-0.015W / cm 2 The plasma action time is 6-10S and its thickness should be 2-2.5nm.

[0017] By setting a wide bandgap transition layer and introducing a high concentration of oxygen atoms, the dangling bonds can be further saturated to effectively enhance the passivation effect, while widening the film band gap and utilizing a lower ultraviolet absorption coefficient in the ultraviolet range to resist the attenuation problem caused by ultraviolet irradiation.

[0018] Furthermore, the wide bandgap dense layer uses silane, hydrogen and carbon dioxide as source gases.

[0019] Furthermore, when the wide bandgap dense layer is deposited, the silane flow rate range is 300-600 sccm, the hydrogen flow rate range is 4000-8000 sccm, and the carbon dioxide doping concentration range is 10%-20%.

[0020] Furthermore, during the deposition of the wide bandgap dense layer, the pressure in the deposition chamber is in the range of 80 Pa to 130 Pa, the temperature is in the range of 165-185 ° C, and the power density of the RF power source is in the range of 0.025-0.04 W / cm 2 The plasma action time is 15-20S and the thickness should be 2-2.5nm.

[0021] By setting a wide bandgap dense layer, the power density of the layer during deposition is increased synchronously by adding hydrogen as a source gas, so that a hydrogen plasma with higher energy can be obtained. This hydrogen plasma can bombard weak bonds to reduce the porosity or disorder of the film and increase its carrier transport efficiency.

[0022] Furthermore, the dense barrier layer uses silane and hydrogen as source gases.

[0023] Furthermore, during the deposition of the dense barrier layer, the silane flow rate range is 300-600 sccm, and the hydrogen flow rate range is 4000-8000 sccm.

[0024] Furthermore, during the deposition of the dense barrier layer, the pressure in the deposition chamber is in the range of 80 Pa to 130 Pa, the temperature is in the range of 165-185 ° C, and the power density of the RF power source is in the range of 0.025-0.04 W / cm 2 The plasma action time is 6-10S and its thickness should be 1-1.5nm.

[0025] By setting a dense barrier layer into which oxygen atoms are not introduced, a higher density than a wide bandgap dense layer can be obtained, which is used to block the subsequent microcrystalline N-doped P atoms from entering the passivation layer.

[0026] Furthermore, the hydrogen treatment layer uses high-purity hydrogen as source gas.

[0027] Furthermore, the hydrogen flow rate ranges from 3000 to 6000 sccm during the deposition of the hydrogen treatment layer.

[0028] Furthermore, during the deposition of the hydrogen-treated layer, the pressure in the deposition chamber is in the range of 100 Pa to 130 Pa, the temperature is in the range of 165-185° C., and the power density of the RF power source is in the range of 0.065-0.1 W / cm 2 , the plasma action time is 15-20S.

[0029] By setting up a hydrogen treatment layer and inserting hydrogen atoms, the stress of the Si-Si bond is eliminated, and atomic recombination is promoted, thereby improving the microstructure of the film, reducing the defect states in the amorphous silicon film, improving the electrical and optical properties of the material, and improving the photothermal stability of the amorphous silicon film, reducing performance degradation during long-term use.

[0030] A high-performance passivation film for a heterojunction solar cell is prepared using the method.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] 1. The multi-layer configuration and thickness ratio of the passivation film of the invention can ensure the stability of the series resistance and fill factor of the battery terminal;

[0033] 2. The unique deposition conditions in the method of the present invention can improve the current loss caused by the intrinsic amorphous silicon film on the front side while ensuring the efficient passivation effect, and can reduce the ultraviolet irradiation attenuation of heterojunction solar cells;

[0034] 3. By setting up an interface anti-epitaxial layer, the epitaxial growth of crystalline silicon can be prevented, and more dangling bonds can be prevented, so that the defect state density cannot increase further;

[0035] 4. By setting a transition layer with a high hydrogen content, the high-density dangling bonds at the interface are passivated by the high hydrogen content, thereby reducing the surface state density, reducing the surface recombination rate, and increasing the carrier life;

[0036] 5. By setting a wide bandgap transition layer and introducing high-concentration oxygen atoms, the dangling bonds can be further saturated to enhance the passivation effect, while widening the film bandgap, and using a lower ultraviolet absorption coefficient in the ultraviolet range to resist the attenuation problem caused by ultraviolet irradiation;

[0037] 6. By setting a wide bandgap dense layer, the power density of the layer during deposition is increased by adding hydrogen as a source gas, and a hydrogen plasma with higher energy can be obtained. This hydrogen plasma can bombard weak bonds to reduce the porosity or disorder of the film and increase its carrier transport efficiency;

[0038] 7. By setting a dense barrier layer, which does not introduce oxygen atoms, a higher density can be obtained compared with a wide bandgap dense layer, which is used to block the subsequent microcrystalline N-doped P atoms from entering the passivation layer;

[0039] 8. By setting up a hydrogen treatment layer and inserting hydrogen atoms, the stress of the Si-Si bond is eliminated, and the atomic recombination is promoted, thereby improving the microstructure of the film, reducing the defect states in the amorphous silicon film, improving the electrical and optical properties of the material, improving the photothermal stability of the amorphous silicon film, and reducing the performance degradation during long-term use. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only represent some embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0041] Figure 1 It is a schematic diagram of the passivation film structure of the present invention.

[0042] Figure 2 This is a comparison chart of external quantum efficiency / reflectivity of Example 1 of the present invention and Comparative Example 7.

[0043] Figure 3 This is a comparison chart of the internal quantum efficiency of Example 1 of the present invention and Comparative Example 7.

[0044] Figure 4 It is a comparison chart of pFF between Example 1 of the present invention and Comparative Example 7.

[0045] Figure 5 It is a Suns-Voc comparison chart of Example 1 of the present invention and Comparative Example 7.

[0046] Figure 6 It is a UV15 comparison diagram of Example 1 of the present invention and Comparative Example 7.

[0047] In the above drawings, the meanings of the various marks are: 1-interface anti-epitaxial layer, 2-transition layer, 3-wide bandgap transition layer, 4-wide bandgap dense layer, 5-dense barrier layer, 6-hydrogen treatment layer. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0049] Example 1

[0050] The above device used in this embodiment is a high-performance passivation film for heterojunction solar cells, and its structure is as follows: Figure 1 As shown, the following steps are included:

[0051] The interface epitaxial prevention layer 1 (a-SiO:HX(i)) is deposited on the textured silicon substrate to prevent the epitaxial growth of crystalline silicon and the generation of more dangling bonds, so that the defect state density cannot rise further. The interface epitaxial prevention layer 1 uses carbon dioxide and silane as source gases, wherein the silane flow rate is 1500sccm and the carbon dioxide doping concentration is 15%. During the deposition process of the silicon-based film, the gas pressure in the deposition chamber is 80Pa and the temperature is 175°C. The RF power density during the deposition is 0.025W / cm 2 , the plasma action time is 2.5S.

[0052] A transition layer 2 (a-Si:HX(i)) is deposited on the interface epitaxial prevention layer 1. The layer has a high hydrogen content. The high hydrogen content passivates the high-density dangling bonds at the interface, thereby reducing the surface state density, reducing the surface recombination rate, and increasing the carrier life. The transition layer 2 uses pure silane as the source gas, wherein the silane flow rate is 1200sccm. During the deposition process of forming the silicon-based film, the gas pressure in the deposition chamber is 45Pa, the temperature is 175°C, and the RF power density during the deposition is 0.0125W / cm 2 , the plasma action time is 5S.

[0053] A wide bandgap transition layer 3 (a-SiO:HX(i)) is deposited on the transition layer 2. This layer introduces high-concentration oxygen atoms on the basis of the transition layer 2, which can effectively further saturate the dangling bonds to enhance the passivation effect. At the same time, the film band gap is widened, and the lower ultraviolet absorption coefficient is used in the ultraviolet range to resist the attenuation problem caused by ultraviolet irradiation. The wide bandgap transition layer 3 uses silane and carbon dioxide as source gases, wherein the silane flow rate is 1200sccm and the carbon dioxide doping concentration is 35%. During the deposition process of the silicon-based film, the air pressure in the deposition chamber is 45Pa, the temperature is 175°C, and the RF power density during the deposition is 0.0125W / cm 2 , the plasma action time is 8S.

[0054] A wide bandgap dense layer 4 (a-SiO:HX(i)) is deposited on the wide bandgap transition layer 3. Compared with the wide bandgap transition layer 3, this layer can obtain a hydrogen plasma with higher energy by increasing the power density during deposition by adding hydrogen as a source gas. This hydrogen plasma can bombard weak bonds to reduce the porosity or disorder of the film and increase its carrier transmission efficiency. The wide bandgap dense layer 4 uses silane, hydrogen and carbon dioxide as source gases, wherein the silane flow rate is 450sccm, the hydrogen flow rate is 6000sccm, and the carbon dioxide doping concentration is 15%. During the deposition process of forming the silicon-based film, the gas pressure in the deposition chamber is 105Pa, the temperature is 175°C, and the RF power density during the deposition is 0.0325W / cm 2 , the plasma action time is 17S.

[0055] A dense barrier layer 5 (a-Si:HX(i)) is deposited on the wide bandgap dense layer 4. Compared with the wide bandgap dense layer 4, this layer does not introduce oxygen atoms, so a higher density can be obtained than the wide bandgap dense layer 4, which is used to block the subsequent microcrystalline N-doped P atoms from entering the passivation layer. The dense barrier layer 5 uses silane and hydrogen as source gases, wherein the silane flow rate is 450sccm and the hydrogen flow rate is 6000sccm. During the deposition process of forming the silicon-based film, the gas pressure in the deposition chamber is 105Pa, the temperature is 175°C, and the RF power density during the deposition is 0.0325W / cm 2 , the plasma action time is 8S.

[0056] Finally, pure hydrogen is used to form hydrogen plasma, and the deposited film is treated to obtain a hydrogen treatment layer 6, which is used to eliminate the stress of the Si-Si bond through the insertion of hydrogen atoms, promote atomic recombination, thereby improving the microstructure of the film, reducing the defect state in the amorphous silicon film, improving the electrical and optical properties of the material, improving the photothermal stability of the amorphous silicon film, and reducing the performance degradation during long-term use. The hydrogen treatment layer 6 uses high-purity hydrogen as the source gas, wherein the hydrogen flow rate is 4500sccm. During the deposition process of forming the silicon-based film, the gas pressure in the deposition chamber is 115Pa, the temperature is 175°C, and the power density of the RF power supply during the deposition is 0.0825W / cm 2 The plasma action time is 17S and the overall thickness of the passivation film is 7-8nm.

[0057] Example 2

[0058] In this embodiment, as a preferred embodiment of the present invention, a high-performance passivation film for heterojunction solar cells is provided, and its structure is as follows Figure 1 As shown, the following steps are included:

[0059] The interface epitaxial prevention layer 1 (a-SiO:HX(i)) is deposited on the textured silicon substrate to prevent the epitaxial growth of crystalline silicon and the generation of more dangling bonds, so that the defect state density cannot rise further. The interface epitaxial prevention layer 1 uses carbon dioxide and silane as source gases, wherein the silane flow rate is 1000sccm and the carbon dioxide doping concentration is 10%. During the deposition process of the silicon-based film, the pressure in the deposition chamber is 50Pa, the temperature is 165°C, and the RF power density during the deposition is 0.02W / cm 2 , the plasma action time is 2S.

[0060] A transition layer 2 (a-Si:HX(i)) is deposited on the interface epitaxial prevention layer 1. The layer has a high hydrogen content. The high hydrogen content passivates the high-density dangling bonds at the interface, thereby reducing the surface state density, reducing the surface recombination rate, and increasing the carrier life. The transition layer 2 uses pure silane as the source gas, wherein the silane flow rate is 800sccm. During the deposition process of forming the silicon-based film, the gas pressure in the deposition chamber is 30Pa, the temperature is 165°C, and the RF power density during the deposition is 0.01W / cm 2 , the plasma action time is 4S.

[0061] A wide bandgap transition layer 3 (a-SiO:HX(i)) is deposited on the transition layer 2. This layer introduces high-concentration oxygen atoms on the basis of the transition layer 2, which can effectively further saturate the dangling bonds to enhance the passivation effect. At the same time, the film band gap is widened, and the lower ultraviolet absorption coefficient is used in the ultraviolet range to resist the attenuation problem caused by ultraviolet irradiation. The wide bandgap transition layer 3 uses silane and carbon dioxide as source gases, wherein the silane flow rate is 800sccm and the carbon dioxide doping concentration is 30%. During the deposition process of the silicon-based film, the gas pressure in the deposition chamber is 30Pa, the temperature is 165°C, and the RF power density during the deposition is 0.01W / cm 2 , the plasma action time is 6S.

[0062] A wide bandgap dense layer 4 (a-SiO:HX(i)) is deposited on the wide bandgap transition layer 3. Compared with the wide bandgap transition layer 3, this layer can obtain a hydrogen plasma with higher energy by increasing the power density during deposition by adding hydrogen as a source gas. This hydrogen plasma can bombard weak bonds to reduce the porosity or disorder of the film and increase its carrier transmission efficiency. The wide bandgap dense layer 4 uses silane, hydrogen and carbon dioxide as source gases, wherein the silane flow rate is 300sccm, the hydrogen flow rate is 4000sccm, and the carbon dioxide doping concentration is 10%. During the deposition process of forming the silicon-based film, the gas pressure in the deposition chamber is 80Pa, the temperature is 165°C, and the RF power density during the deposition is 0.025W / cm2 , the plasma action time is 15S.

[0063] A dense barrier layer 5 (a-Si:HX(i)) is deposited on the wide bandgap dense layer 4. Compared with the wide bandgap dense layer 4, this layer does not introduce oxygen atoms, so a higher density can be obtained than the wide bandgap dense layer 4, which is used to block the subsequent microcrystalline N-doped P atoms from entering the passivation layer. The dense barrier layer 5 uses silane and hydrogen as source gases, wherein the silane flow rate is 300sccm and the hydrogen flow rate is 4000sccm. During the deposition process of forming the silicon-based film, the gas pressure in the deposition chamber is 80Pa, the temperature is 165°C, and the RF power density during the deposition is 0.025W / cm 2 , the plasma action time is 6S.

[0064] Finally, pure hydrogen is used to form hydrogen plasma, and the deposited film is treated to obtain a hydrogen treatment layer 6, which is used to eliminate the stress of the Si-Si bond through the insertion of hydrogen atoms, promote atomic recombination, thereby improving the microstructure of the film, reducing the defect state in the amorphous silicon film, improving the electrical and optical properties of the material, improving the photothermal stability of the amorphous silicon film, and reducing the performance degradation during long-term use. The hydrogen treatment layer 6 uses high-purity hydrogen as the source gas, wherein the hydrogen flow rate is 3000sccm. During the deposition process of forming the silicon-based film, the gas pressure in the deposition chamber is 100Pa, the temperature is 165°C, and the power density of the RF power supply during the deposition is 0.065W / cm 2 The plasma action time is 15S and the overall thickness of the passivation film is 6-7nm.

[0065] Example 3

[0066] In this embodiment, as a preferred embodiment of the present invention, a high-performance passivation film for heterojunction solar cells is provided, and its structure is as follows Figure 1 As shown, the following steps are included:

[0067] The interface epitaxial prevention layer 1 (a-SiO:HX(i)) is deposited on the silicon substrate after texturing to prevent the epitaxial growth of crystalline silicon and the generation of more dangling bonds, so that the defect state density cannot rise further. The interface epitaxial prevention layer 1 uses carbon dioxide and silane as source gases, wherein the silane flow rate is 2000sccm and the carbon dioxide doping concentration is 20%. During the deposition process of forming the silicon-based film, the gas pressure in the deposition chamber is 110Pa and the temperature is 185°C. The power density of the RF power supply during the deposition is 0.03W / cm 2 , the plasma action time is 3S.

[0068] A transition layer 2 (a-Si:HX(i)) is deposited on the interface epitaxial prevention layer 1. The layer has a high hydrogen content. The high hydrogen content passivates the high-density dangling bonds at the interface, thereby reducing the surface state density, reducing the surface recombination rate, and increasing the carrier life. The transition layer 2 uses pure silane as the source gas, wherein the silane flow rate is 1600sccm. During the deposition process of forming the silicon-based film, the gas pressure in the deposition chamber is 60Pa, the temperature is 185°C, and the RF power density during the deposition is 0.015W / cm 2 , the plasma action time is 6S.

[0069] A wide bandgap transition layer 3 (a-SiO:HX(i)) is deposited on the transition layer 2. This layer introduces high-concentration oxygen atoms on the basis of the transition layer 2, which can effectively further saturate the dangling bonds to enhance the passivation effect. At the same time, the film band gap is widened, and the lower ultraviolet absorption coefficient is used in the ultraviolet range to resist the attenuation problem caused by ultraviolet irradiation. The wide bandgap transition layer 3 uses silane and carbon dioxide as source gases, wherein the silane flow rate is 1600sccm and the carbon dioxide doping concentration is 40%. During the deposition process of the silicon-based film, the gas pressure in the deposition chamber is 60Pa, the temperature is 185°C, and the RF power density during the deposition is 0.015W / cm 2 , the plasma action time is 10S.

[0070] A wide bandgap dense layer 4 (a-SiO:HX(i)) is deposited on the wide bandgap transition layer 3. Compared with the wide bandgap transition layer 3, this layer can obtain a hydrogen plasma with higher energy by increasing the power density during deposition by adding hydrogen as a source gas. This hydrogen plasma can bombard weak bonds to reduce the porosity or disorder of the film and increase its carrier transmission efficiency. The wide bandgap dense layer 4 uses silane, hydrogen and carbon dioxide as source gases, wherein the silane flow rate is 600sccm, the hydrogen flow rate is 8000sccm, and the carbon dioxide doping concentration is 20%. During the deposition process of forming the silicon-based film, the gas pressure in the deposition chamber is 130Pa, the temperature is 185°C, and the RF power density during the deposition is 0.04W / cm 2 , the plasma action time is 20S.

[0071] A dense barrier layer 5 (a-Si:HX(i)) is deposited on the wide bandgap dense layer 4. Compared with the wide bandgap dense layer 4, this layer does not introduce oxygen atoms, so a higher density can be obtained than the wide bandgap dense layer 4, which is used to block the subsequent microcrystalline N-doped P atoms from entering the passivation layer. The dense barrier layer 5 uses silane and hydrogen as source gases, wherein the silane flow rate is 600sccm and the hydrogen flow rate is 8000sccm. During the deposition process of forming the silicon-based film, the gas pressure in the deposition chamber is 130Pa, the temperature is 185°C, and the RF power density during the deposition is 0.04W / cm 2 , the plasma action time is 10S.

[0072] Finally, pure hydrogen is used to form hydrogen plasma, and the deposited film is treated to obtain a hydrogen treatment layer 6, which is used to eliminate the stress of the Si-Si bond through the insertion of hydrogen atoms, promote atomic recombination, thereby improving the microstructure of the film, reducing the defect state in the amorphous silicon film, improving the electrical and optical properties of the material, improving the photothermal stability of the amorphous silicon film, and reducing the performance degradation during long-term use. The hydrogen treatment layer 6 uses high-purity hydrogen as the source gas, wherein the hydrogen flow rate is 6000sccm. During the deposition process of forming the silicon-based film, the gas pressure in the deposition chamber is 130Pa, the temperature is 185°C, and the power density of the RF power supply during the deposition is 0.1W / cm 2 The plasma action time is 20S and the overall thickness of the passivation film is 8-9nm.

[0073] Comparative Example 1

[0074] In this embodiment, as a comparative example of the present invention, a high-performance passivation film for heterojunction solar cells is improved on the basis of Example 1 only in that the interface anti-epitaxial layer is removed, and the other layers are thickened compared with the same period to maintain the overall thickness of the passivation film at 7-8nm.

[0075] Comparative Example 2

[0076] In this embodiment, as a comparative example of the present invention, a high-performance passivation film for heterojunction solar cells is improved on the basis of Example 1 only in that the transition layer is removed, and the other layers are thickened compared with the same period, maintaining the overall thickness of the passivation film at 7-8nm.

[0077] Comparative Example 3

[0078] In this embodiment, as a comparative example of the present invention, a high-performance passivation film for heterojunction solar cells is improved on the basis of Example 1 only in that the wide bandgap transition layer is removed, and the other layers are thickened compared with the same period, maintaining the overall thickness of the passivation film at 7-8nm.

[0079] Comparative Example 4

[0080] In this embodiment, as a comparative example of the present invention, a high-performance passivation film for heterojunction solar cells is improved on the basis of Example 1 only in that the wide bandgap dense layer is removed, and the other layers are thickened compared with the same period, maintaining the overall thickness of the passivation film at 7-8nm.

[0081] Comparative Example 5

[0082] In this embodiment, as a comparative example of the present invention, a high-performance passivation film for heterojunction solar cells is improved on the basis of Example 1 only in that the dense barrier layer is removed, and the other layers are thickened compared with the same period, maintaining the overall thickness of the passivation film at 7-8nm.

[0083] Comparative Example 6

[0084] In this embodiment, as a comparative example of the present invention, a high-performance passivation film for heterojunction solar cells is improved on the basis of Example 1 only in that the hydrogen treatment layer is removed, and the other layers are thickened compared with the same period, maintaining the overall thickness of the passivation film at 7-8nm.

[0085] Comparative Example 7

[0086] In this embodiment, as a comparative example of the present invention, a high-performance passivation film for heterojunction solar cells is prepared using conventional means. The specific steps are:

[0087] Silane was used as the source gas, wherein the silane flow rate was 1000 sccm, the gas pressure in the deposition chamber was 80 Pa, the temperature was 175°C, and the RF power density during the deposition was 0.025 W / cm 2 , the plasma action time is 5S, and an intrinsic layer 1 is deposited on the silicon wafer substrate.

[0088] Silane was used as the source gas, wherein the silane flow rate was 800 sccm, the gas pressure in the deposition chamber was 40 Pa, the temperature was 175°C, and the power density of the RF power supply during the deposition was 0.015 W / cm 2 , the plasma action time is 10S, and the intrinsic layer 2 is deposited on the intrinsic layer 1.

[0089] Silane and hydrogen were used as source gases, wherein the silane flow rate was 600 sccm and the hydrogen flow rate was 6000 sccm. The pressure in the deposition chamber was 100 Pa, the temperature was 175°C, and the RF power density during the deposition was 0.04 W / cm 2 The plasma action time is 20S, and the intrinsic layer 3 is deposited on the intrinsic layer 2. The overall thickness of the passivation film is 7-8nm.

[0090] The quantum efficiency of the heterojunction solar cells using the conventional passivation films in Example 1 and Comparative Example 7 was tested, and the comparison of the external quantum efficiency / reflectivity and internal quantum efficiency was as follows: Figure 2 , 3 The heterojunction solar cell using the passivation film in Example 1 has a significant advantage in both external quantum efficiency and internal quantum efficiency in the short-wave band, and the current density is increased by 0.17 mA / CM compared to the heterojunction solar cell using the conventional passivation film. 2 .

[0091] The heterojunction solar cells using conventional passivation films in Example 1 and Comparative Example 7 were tested for Suns-Voc, and the pFF and Suns-Voc comparisons were as follows: Figure 4 , 5 As shown, the heterojunction solar cell using the high-performance passivation layer of the present invention has higher pFF and Suns-Voc than the conventional heterojunction solar cell of the production line, which indicates that the passivation performance of the high-performance passivation layer of the present invention is better than the passivation performance of the conventional passivation film of the production line.

[0092] The high-performance passivation layer of the invention and the conventional passivation layer of the production line were deposited on the wafer respectively, and the film performance was tested and compared using an ellipsometer, as shown in Table 1 below.

[0093] Table 1

[0094]

[0095] As shown in Table 1, the conventional passivation layer is compared with the high-performance passivation layer of this invention. The high-performance passivation layer of this invention has a larger band gap (Eg), which helps to achieve better spectral selectivity. The high-performance passivation layer of this invention has a smaller extinction coefficient (k), which means that the material has weaker absorption and scattering of light waves, which helps to reduce the current loss caused by the front passivation layer in the heterojunction battery.

[0096] The heterojunction solar cells using the high-performance passivation layer of the invention and the conventional heterojunction solar cells in the production line were tested by UVID (UV15 / 15KW·h / m 2 ), the conversion efficiency attenuation is compared as follows Figure 6 As shown, after UV15, the heterojunction solar cell using the high-performance passivation layer of the invention has a smaller attenuation and higher efficiency.

[0097] The IV properties of Example 1 and Comparative Examples 1-6 are shown in Table 2 below.

[0098] Table 2

[0099]

[0100] It can be seen from Table 2 that when the passivation layers of the various process embodiments are used, the battery conversion efficiency is relatively stable; when the passivation layers of the various process comparison examples are used, there are different degrees of efficiency loss compared to the embodiments.

[0101] The above are the implementation methods listed in this embodiment, but this embodiment is not limited to the above optional implementation methods. Those skilled in the art can arbitrarily combine the above methods to obtain other various implementation methods. Anyone can derive other various forms of implementation methods under the inspiration of this embodiment. The above specific implementation methods should not be understood as limiting the scope of protection of this embodiment. The scope of protection of this embodiment shall be based on the definition in the claims, and the description can be used to interpret the claims.

Claims

1. A method for preparing a high-performance passivation film for a heterojunction solar cell, characterized in that: The following steps are involved: Depositing five layers of silicon-based films and a hydrogen treatment layer (6) in sequence on the textured silicon substrate, wherein the five layers of silicon-based films are, in sequence, an interface anti-epitaxial layer (1), a transition layer (2), a wide-bandgap transition layer (3), a wide-bandgap dense layer (4) and a dense barrier layer (5); The interface anti-epitaxial layer (1) uses carbon dioxide and silane as source gases, the transition layer (2) uses pure silane as source gas, the wide bandgap transition layer (3) uses silane and carbon dioxide as source gases, the wide bandgap dense layer (4) uses silane, hydrogen and carbon dioxide as source gases, and the dense barrier layer (5) uses silane and hydrogen as source gases; When the interface anti-epitaxial layer (1) is deposited, the silane flow rate range is 1000-2000sccm, the carbon dioxide doping concentration range is 10%-20%, the air pressure range in the deposition chamber when the interface anti-epitaxial layer (1) is deposited is 50Pa-110Pa, the temperature range is 165-185°C, and the radio frequency power density range during deposition is 0.02-0.03W / cm 2 , the plasma action time is 2-3s, and its thickness should be 0.5-1nm; When the transition layer (2) is deposited, the silane flow rate range is 800-1600 sccm, the gas pressure range in the deposition chamber is 30Pa-60Pa, the temperature range is 165-185°C, and the radio frequency power density range is 0.01-0.015W / cm 2 , the plasma action time is 4-6s, and its thickness should be 1-1.5nm; When the wide bandgap transition layer (3) is deposited, the silane flow rate range is 800-1600 sccm, the carbon dioxide doping concentration range is 30%-40%, the air pressure range in the deposition chamber when the wide bandgap transition layer (3) is deposited is 30Pa-60Pa, the temperature range is 165-185°C, and the radio frequency power density range during deposition is 0.01-0.015W / cm 2 , the plasma action time is 6-10s, and its thickness should be 2-2.5nm; When the wide bandgap dense layer (4) is deposited, the silane flow rate range is 300-600sccm, the hydrogen flow rate range is 4000-8000sccm, the carbon dioxide doping concentration range is 10%-20%, the air pressure range in the deposition chamber when the wide bandgap dense layer (4) is deposited is 80Pa-130Pa, the temperature range is 165-185°C, and the radio frequency power density range during deposition is 0.025-0.04W / cm 2 , the plasma action time is 15-20s, and its thickness should be 2-2.5nm; When the dense barrier layer (5) is deposited, the silane flow rate range is 300-600 sccm, the hydrogen flow rate range is 4000-8000 sccm, the gas pressure range in the deposition chamber when the dense barrier layer (5) is deposited is 80Pa-130Pa, the temperature range is 165-185°C, and the radio frequency power density range is 0.025-0.04W / cm 2 The plasma action time is 6-10s and its thickness should be 1-1.5nm.

2. The method for preparing a high-performance passivation film for a heterojunction solar cell according to claim 1, characterized in that: The hydrogen treatment layer (6) uses high-purity hydrogen as source gas.

3. The method for preparing a high-performance passivation film for a heterojunction solar cell according to claim 2, characterized in that: When the hydrogen treatment layer (6) is deposited, the hydrogen flow rate range is 3000-6000 sccm, the gas pressure range in the deposition chamber is 100Pa-130Pa, the temperature range is 165-185°C, and the radio frequency power density range is 0.065-0.1W / cm 2 , the plasma action time is 15-20s.

4. A high-performance passivation film for heterojunction solar cells, characterized in that: The high-performance passivation film is prepared by using the method for preparing a high-performance passivation film for a heterojunction solar cell as described in any one of claims 1 to 3.

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