Solar cell passivation structure and preparation method and application thereof

Abstract

The invention discloses a solar cell passivation structure and a preparation method and application thereof. The preparation method comprises the following steps: preparing an aluminum oxide film layer on a substrate; the method for preparing the aluminum nitride film layer on the surface of the aluminum oxide film through the PECVD technology comprises the steps that the PECVD technology is adopted, a first aluminum nitride film layer is prepared on the surface of the aluminum oxide film layer under first power, and then a second aluminum nitride film layer is prepared on the surface of the first aluminum nitride film layer under second power larger than the first power. According to the method, the first aluminum nitride film layer is prepared on the surface of the aluminum oxide film layer through low-power PECVD, so that the aluminum oxide film layer can be protected, the situation that the efficiency and the production reject ratio of a solar cell are reduced due to the fact that the aluminum oxide film layer is damaged by too high power is prevented, and the production efficiency and the device efficiency are improved; and the passivation structure is constructed by compositing the aluminum nitride film layer and the oxide film layer prepared by adopting the step-by-step power, so that the passivation effect of the passivation structure can be effectively improved, and the efficiency of the solar cell is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cells, and in particular to a solar cell passivation structure and a preparation method and application thereof. Background Art

[0002] With the continuous development of the photovoltaic industry, solar cell technology is constantly updated and iterated, and improving efficiency and reducing costs are eternal topics in the development of photovoltaics. In order to further improve the efficiency of solar cells, researchers have conducted research and development on the structure of solar cells. The TOPCon cells that currently occupy a major market share generally use an aluminum oxide film layer as the front passivation layer. Due to its good passivation effect, aluminum oxide materials are introduced into solar cells as a passivation layer, and its preparation technology mainly includes atomic layer deposition (ALD) and plasma enhanced chemical vapor deposition (PECVD). The current mainstream aluminum oxide preparation is mainly atomic layer deposition (ALD). The ALD technology of aluminum oxide is a technology that achieves aluminum oxide deposition by alternately introducing aluminum-containing precursor molecules and oxygen-containing precursor molecules to the surface of the substrate. The principle of ALD technology is to form a monolayer of molecules on the surface of the substrate, and these monolayer molecules can be converted into an oxide film through chemical reactions.

[0003] TOPCon cells typically use aluminum oxide as a passivation layer, but its passivation effect still needs to be improved, and thus the cell efficiency needs to be further improved. Furthermore, the conventional PECVD process, which adds other passivation material layers to the aluminum oxide layer, can damage the aluminum oxide layer on the substrate surface, increasing production defect rates and failing to effectively improve the passivation effect and thus solar cell efficiency. Furthermore, current passivation layer preparation methods generally fail to balance device efficiency with production efficiency. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a solar cell passivation structure and a preparation method and application thereof.

[0005] A first aspect of the present invention provides a method for preparing a solar cell passivation structure, comprising:

[0006] preparing an aluminum oxide film layer on a substrate;

[0007] An aluminum nitride film layer is prepared on the surface of the aluminum oxide film layer facing away from the substrate using plasma enhanced chemical vapor deposition (PECVD) technology, including: using plasma enhanced chemical vapor deposition technology, at a first power, preparing a first aluminum nitride film layer on the surface of the aluminum oxide film layer facing away from the substrate, and then at a second power, preparing a second aluminum nitride film layer on the surface of the first aluminum nitride film layer facing away from the aluminum oxide film layer, wherein the first power is less than the second power.

[0008] The method for preparing a solar cell passivation structure according to an embodiment of the present invention has at least the following beneficial effects: the method for preparing a solar cell passivation structure adopts a layered process route to prepare an aluminum oxide film layer and an aluminum nitride film layer. Specifically, after the aluminum oxide film layer is prepared, a plasma enhanced chemical vapor deposition (PECVD) technique is further adopted to prepare an aluminum nitride film layer to composite with the aluminum oxide film layer to construct a passivation structure, and the PECVD preparation of the aluminum oxide film layer adopts a low-high step-by-step power mode, wherein, before the second aluminum nitride film layer is prepared by high-power PECVD, a first aluminum nitride film layer is first prepared on the surface of the aluminum oxide film layer facing away from the substrate by low-power PECVD, which can protect the aluminum oxide film layer. It can be used to prevent excessive power from damaging the aluminum oxide film layer and reducing the efficiency and production defect rate of solar cells; and by adopting the above step-by-step power to prepare the aluminum nitride film layer and the aluminum oxide film layer to construct a passivation structure, the passivation effect of the passivation structure can be effectively improved, and the efficiency of the solar cell (i.e., photoelectric conversion efficiency) can be improved; in addition, due to the protective effect of the first aluminum nitride film layer prepared by low-power PECVD, when preparing the second aluminum nitride film layer, appropriately increasing the deposition power will not have a significant negative impact on the final battery efficiency, which can relatively improve production efficiency and reduce time costs, thereby effectively ensuring the passivation effect and battery efficiency while increasing production capacity, taking into account both device efficiency and effective efficiency, and achieving the effect of reducing costs and increasing efficiency.

[0009] In some embodiments of the present invention, the first power is less than or equal to 6000 W, and / or the second power is greater than 6000 W. For example, the first power may be any value of 3000 W, 3200 W, 3500 W, 3600 W, 3800 W, 4000 W, 4300 W, 4500 W, 4800 W, 5000 W, 5100 W, 5200 W, 5500 W, 5700 W, 5800 W, or 6000 W, or a range of any two of the values. The second power may be any value of 6200W, 6500W, 7000W, 7500W, 7800W, 8000W, 8500W, 9000W, 9500W, 10000W, 10500W, 11000W, 12000W, 12500W, 13000W, 13500W, 14000W, 15000W, 15500W, 16000W, 18000W, 18500W, 19000W, and 20000W, or a range of any two of them.

[0010] In the process of preparing aluminum nitride film layers by PECVD technology, the first aluminum nitride film layer is first prepared at low power. The lower the power, the lower the reaction intensity, and the less damage to the aluminum oxide film layer on the surface of the substrate. In combination with a shorter reaction time, a thinner first aluminum nitride film layer can be controlled to be generated on the surface of the aluminum oxide film layer; then the second aluminum nitride film layer is prepared at high power. The higher the power, the more intense the reaction, and a higher film thickness can be obtained within a certain period of time. In addition, based on the protection of the aluminum oxide film layer on the surface of the substrate by the first aluminum nitride film layer previously prepared at low power, the damage to its surface caused by high power can be reduced or even avoided. The thickness of the second aluminum nitride film layer can be controlled by controlling the reaction time.

[0011] In some embodiments of the present invention, when an aluminum nitride film is formed on an aluminum oxide film using PECVD technology, the nitrogen-containing precursor used may be at least one of ammonia and nitrogen, and the aluminum-containing precursor may be at least one of trimethylaluminum (TMA) and triethylaluminum (TEM). The volume flow rate of the nitrogen-containing precursor may be controlled between 1000 sccm and 10,000 sccm, and the volume flow rate of the aluminum-containing precursor may be controlled between 500 sccm and 5000 sccm.

[0012] In some embodiments of the present invention, the temperature of the aluminum nitride film layer prepared on the surface of the aluminum oxide film layer by PECVD technology can be controlled in the range of 150°C to 300°C. For example, the temperature can be any value of 150°C, 160°C, 165°C, 170°C, 180°C, 185°C, 200°C, 210°C, 215°C, 220°C, 230°C, 245°C, 250°C, 260°C, 265°C, 270°C, 280°C, 290°C, 300°C or any two of the values; the pressure can be controlled in the range of 500mtorr to 350 0mtorr, for example, the pressure can be any value among 500mtorr, 600mtorr, 800mtorr, 1000mtorr, 1100mtorr, 1250mtorr, 1500mtorr, 1700mtorr, 1800mtorr, 2000mtorr, 2350mtorr, 2500mtorr, 2600mtorr, 2850mtorr, 3000mtorr, 3200mtorr, and 3500mtorr, or a range of any two of them. In addition, the deposition time of the first aluminum nitride film layer prepared by low-power PECVD can be controlled within a range of 30s to 300s; the deposition time of the second aluminum nitride film layer prepared by high-power PECVD can also be controlled within a range of 30s to 300s.

[0013] In some embodiments of the present invention, the thickness of the first aluminum nitride film layer is 0.1 nm to 2.5 nm; and / or the thickness of the second aluminum nitride film layer is 1 nm to 6 nm. For example, the thickness of the first aluminum nitride film layer may be any value among 0.1 nm, 0.3 nm, 0.5 nm, 0.8 nm, 1 nm, 1.2 nm, 1.5 nm, 1.6 nm, 1.7 nm, 1.8 nm, 2 nm, 2.1 nm, 2.3 nm, 2.5 nm, or a range of any two of the values. The thickness of the second aluminum nitride film layer may be any value among 1 nm, 1.2 nm, 1.5 nm, 1.7 nm, 2 nm, 2.1 nm, 2.3 nm, 2.5 nm, 2.8 nm, 3 nm, 3.2 nm, 3.5 nm, 3.7 nm, 4 nm, 4.5 nm, 4.6 nm, 5 nm, 5.3 nm, 5.5 nm, 5.7 nm, 5.9 nm, or 6 nm, or a range of any two of the values.

[0014] In some embodiments of the present invention, the total thickness of the first aluminum nitride film layer and the second aluminum nitride film layer is 3 nm to 7 nm. For example, the total thickness of the first aluminum nitride film layer and the second aluminum nitride film layer can be any value among 3 nm, 3.2 nm, 3.3 nm, 3.5 nm, 3.6 nm, 3.8 nm, 4 nm, 4.3 nm, 4.5 nm, 4.7 nm, 5 nm, 5.2 nm, 5.3 nm, 5.5 nm, 5.8 nm, 6 nm, 6.2 nm, 6.4 nm, 6.5 nm, 6.7 nm, 6.9 nm, and 7 nm, or any range of two values.

[0015] In some embodiments of the present invention, the thickness of the first aluminum nitride film layer is less than the thickness of the second aluminum nitride film layer. As described above, forming the first aluminum nitride film layer on the surface of the aluminum oxide film layer through a low-power PECVD process can protect the aluminum oxide film layer, preventing excessive power from damaging the aluminum oxide film layer and reducing the efficiency and production defect rate of the solar cell. In addition, the thickness of the second aluminum nitride film layer formed by high-power PECVD is controlled to be greater than the thickness of the first aluminum nitride film layer formed by low-power PECVD. Under the protective effect of the first aluminum nitride film layer formed at low power, the efficiency of the aluminum nitride film formed at high power is high, thereby reducing time costs and improving production efficiency.

[0016] After research and experiments, the above PECVD technology is used to prepare aluminum nitride film layers through a low and high step-by-step power mode. Within the effective film layer range, a higher film thickness has a gain in efficiency. Since the product of power and time in the process of depositing aluminum nitride film layers using PECVD technology represents energy, the film thickness hardly changes when the total energy value remains unchanged. Therefore, if only high-power PECVD is used to prepare a single aluminum nitride film layer, a higher film thickness needs to be prepared, which requires increasing the reaction power and increasing the high-power deposition reaction time. This will increase the degree of damage to the target state of the substrate and easily produce negative effects. First, the first aluminum nitride film layer is prepared by low-power PECVD as a protective film layer, which can connect the aluminum oxide film layer and the second aluminum nitride film layer prepared by high-power PECVD to prevent the surface state of the aluminum oxide film layer from being damaged and affecting the battery efficiency and production defect rate.

[0017] In addition, within the same reaction time, the above-mentioned PECVD technology for preparing an aluminum nitride film layer through a low-to-high step-by-step power mode has the advantage of a preparation method. The thickness of the aluminum nitride film layer can be increased by increasing the second power, or the efficiency can be increased. Compared with the single-power PECVD method for preparing an aluminum nitride film layer, it can effectively ensure the efficiency of the device while reducing the time cost, increasing production capacity, and achieving the effect of reducing costs and increasing efficiency. Moreover, compared with the single-power PECVD method for preparing an aluminum nitride film layer, when the target aluminum nitride film thickness is the same, the above-mentioned PECVD technology for preparing an aluminum nitride film layer through a low-to-high step-by-step power mode can appropriately adjust the second power and reaction time, significantly shortening the preparation time without affecting the device efficiency.

[0018] In some embodiments of the present invention, the aluminum oxide film is prepared using atomic layer deposition technology. Specifically, the aluminum oxide film can be prepared by sequentially introducing an oxygen-containing precursor and an aluminum-containing precursor to react to prepare the aluminum oxide film.

[0019] In some embodiments of the present invention, the oxygen-containing precursor may be at least one of water vapor, oxygen, and ozone, and the volume flow rate of the oxygen-containing precursor may be controlled to be 50 sccm to 3000 sccm.

[0020] In some embodiments of the present invention, the aluminum-containing precursor may be at least one of trimethylaluminum (TMA) and triethylaluminum (TEM), and the volume flow rate of the aluminum-containing precursor may be controlled to be 500 sccm to 3000 sccm.

[0021] In some embodiments of the present invention, the temperature of the process of preparing the aluminum oxide film using the atomic layer deposition technology is controlled to be 150° C. to 300° C. For example, the temperature of the atomic layer deposition process can be controlled to be any value among 150° C., 160° C., 165° C., 175° C., 180° C., 190° C., 200° C., 210° C., 215° C., 220° C., 230° C., 235° C., 250° C., 255° C., 265° C., 270° C., 280° C., 285° C., 290° C., and 300° C., or any two ranges thereof.

[0022] In some embodiments of the present invention, the pressure of the process of preparing an aluminum oxide film using atomic layer deposition technology is controlled to be 500mtorr to 3500mtorr. For example, the pressure of the atomic layer deposition process can be controlled to be any value among 500mtorr, 600mtorr, 800mtorr, 850mtorr, 900mtorr, 1000mtorr, 1200mtorr, 1500mtorr, 1600mtorr, 1750mtorr, 1800mtorr, 2000mtorr, 2300mtorr, 2500mtorr, 2700mtorr, 3000mtorr, 3100mtorr, 3250mtorr, 3300mtorr, and 3500, or a range of any two of them.

[0023] In some embodiments of the present invention, the aluminum oxide film is prepared by atomic layer deposition technology under at least one of nitrogen and argon atmospheres.

[0024] In some embodiments of the present invention, the thickness of the aluminum oxide film layer is 1 nm to 3 nm. For example, the thickness of the aluminum oxide film layer can be any value among 1 nm, 1.2 nm, 1.3 nm, 1.5 nm, 1.6 nm, 1.65 nm, 1.7 nm, 1.8 nm, 1.85 nm, 1.9 nm, 2 nm, 2.1 nm, 2.2 nm, 2.35 nm, 2.4 nm, 2.5 nm, 2.65 nm, 2.8 nm, and 3 nm, or any range of two thereof.

[0025] In some embodiments of the present invention, the substrate is a silicon substrate.

[0026] In some embodiments of the present invention, the substrate is a silicon substrate, and the aluminum oxide film is prepared using atomic layer deposition (ALD). ALD can be used to prepare the aluminum oxide film by sequentially introducing an oxygen-containing precursor and an aluminum-containing precursor to react with each other. The introduction of the oxygen-containing precursor first can pre-clean the surface of the silicon substrate and deposit a layer of hydroxyl groups on the surface of the silicon substrate, which facilitates subsequent reaction with the aluminum-containing precursor, thereby improving the structural density of the aluminum oxide film.

[0027] In some embodiments of the present invention, the substrate is an N-type silicon substrate.

[0028] In a second aspect of the present invention, a solar cell passivation structure is provided, which is manufactured by any of the aforementioned methods for preparing a solar cell passivation structure.

[0029] In some embodiments of the present invention, the solar cell passivation structure includes an aluminum oxide film layer provided on a substrate and an aluminum nitride film layer provided on a surface of the aluminum oxide film layer facing away from the substrate, the aluminum nitride film layer includes a first aluminum nitride film layer and a second aluminum nitride film layer, and the first aluminum nitride film layer is sandwiched between the second aluminum nitride film layer and the aluminum oxide film layer.

[0030] The third aspect of the present invention provides a method for preparing any of the aforementioned solar cell passivation structures of the present invention or an application of any of the aforementioned solar cell passivation structures in preparing a solar cell.

[0031] A fourth aspect of the present invention provides a solar cell comprising any of the aforementioned solar cell passivation structures of the present invention.

[0032] In some embodiments of the present invention, with the substrate as a reference, the solar cell includes, from the inside to the outside on one side in the thickness direction of the substrate, an emitter, the solar cell passivation structure, and a first anti-reflection layer;

[0033] Taking the substrate as a reference, the solar cell includes, from the inside to the outside, a tunneling oxide layer, a polysilicon layer, and a second anti-reflection layer on the other side of the substrate in the thickness direction.

[0034] In some embodiments of the present invention, based on the substrate, the solar cell includes, from the inside to the outside, an emitter, a solar cell passivation structure, and a first anti-reflection layer on the front surface of the substrate;

[0035] Taking the substrate as a reference, the solar cell comprises a tunneling oxide layer, a polysilicon layer and a second anti-reflection layer in sequence from the inside to the outside on the back surface of the substrate.

[0036] In some embodiments of the present invention, the substrate is a silicon substrate.

[0037] In some embodiments of the present invention, the substrate is an N-type silicon substrate, and the emitter is a P-type emitter.

[0038] In some embodiments of the present invention, the solar cell further comprises a first electrode and a second electrode; the first electrode is disposed on the side of the first anti-reflection layer disposed in the thickness direction of the substrate, and one end of the first electrode penetrates the first anti-reflection layer to be electrically connected to the second aluminum nitride film layer in the solar cell passivation structure, while the other end is exposed on the surface of the solar cell; the second electrode is disposed on the side of the second anti-reflection layer disposed in the thickness direction of the substrate, and one end of the second electrode penetrates the second anti-reflection layer to be electrically connected to the polysilicon layer, while the other end is also exposed on the surface of the solar cell. In some embodiments, the first electrode is a front electrode, and the second electrode is a back electrode.

[0039] A fifth aspect of the present invention provides a method for preparing a solar cell, comprising the following steps:

[0040] On one side of the substrate in the thickness direction, an emitter, a solar cell passivation structure and a first anti-reflection layer are sequentially prepared from the inside to the outside;

[0041] On the other side of the substrate in the thickness direction, a tunnel oxide layer, a polysilicon layer, and a second anti-reflection layer are sequentially formed from the inside to the outside;

[0042] A first electrode is formed on the side where the first anti-reflection layer is provided in the thickness direction of the substrate; and a second electrode is formed on the side where the second anti-reflection layer is provided in the thickness direction of the substrate to produce a solar cell.

[0043] Among them, the preparation of the solar passivation structure includes: preparing an aluminum oxide film layer on the surface of the emitter facing away from the substrate; and then using plasma enhanced chemical vapor deposition technology to prepare an aluminum nitride film layer on the surface of the aluminum oxide film layer facing away from the emitter, specifically including: using plasma enhanced chemical vapor deposition technology, at a first power, preparing a first aluminum nitride film layer on the surface of the aluminum oxide film layer facing away from the emitter, and then at a second power, preparing a second aluminum nitride film layer on the surface of the first aluminum nitride film layer facing away from the aluminum oxide film layer, wherein the first power is less than the second power.

[0044] In the above solar cell preparation method, the preparation of the solar cell passivation structure adopts a layered process route to prepare an aluminum oxide film layer and an aluminum nitride film layer. Specifically, after the aluminum oxide film layer is prepared, the aluminum nitride film layer is further prepared by PECVD technology to composite with the aluminum oxide film layer to construct a passivation structure, and the PECVD preparation of the aluminum oxide film layer adopts a low-high step-by-step power mode. Before the second aluminum nitride film layer is prepared by high-power PECVD, the first aluminum nitride film layer is first prepared on the surface of the aluminum oxide film layer facing away from the substrate by low-power PECVD, which can protect the aluminum oxide film layer and prevent Excessive power will damage the aluminum oxide film layer and reduce the efficiency and production defect rate of solar cells, thereby effectively improving the passivation effect of the passivation structure and improving the efficiency of solar cells (i.e., photoelectric conversion efficiency); in addition, due to the protective effect of the first aluminum nitride film layer prepared by low-power PECVD, when preparing the second aluminum nitride film layer, appropriately increasing the deposition power will not have a significant negative impact on the final battery efficiency, which can relatively improve production efficiency and reduce time costs, thereby effectively ensuring the passivation effect and battery efficiency while increasing production capacity, taking into account both device efficiency and effective efficiency, and achieving the effect of reducing costs and increasing efficiency.

[0045] In some embodiments of the present invention, the first electrode is a front electrode, and the second electrode is a back electrode. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0047] Figure 1 FIG. 1 is a schematic structural diagram of a solar cell according to an embodiment of the present invention. DETAILED DESCRIPTION

[0048] The following will clearly and completely describe the concept and technical effects of the present invention in conjunction with the embodiments to fully understand the purpose, features and effects of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of the present invention.

[0049] Example 1

[0050] This embodiment provides a method for preparing a solar cell passivation structure, comprising the following steps:

[0051] S1. Preparing an aluminum oxide film layer on a silicon substrate by atomic layer deposition, specifically comprising:

[0052] ① Boat paddle: Use a manipulator to grab the graphite boat loaded with silicon substrate from the docking station and place it on the boat pusher;

[0053] ②Boat entry: send the graphite boat on the paddle into the heating furnace tube;

[0054] The time setting for this step is 120 s, the temperature in the furnace is 240°C, the nitrogen flow rate in the furnace is 10,000 sccm, and the pressure in the furnace is 10,000 mtorr.

[0055] ③ Constant temperature: The graphite boat is kept at a constant temperature to the set temperature in the furnace at normal pressure;

[0056] The time setting for this step is 320 seconds, the temperature in the furnace is 240°C, the gas in the furnace is 0 sccm, the pressure in the furnace is 10,000 mtorr, and the auxiliary heating is turned on for 180 seconds and at 280°C.

[0057] ④ Vacuuming: Open the main pumping valve to pump the furnace to a vacuum low-pressure state;

[0058] The time setting for this step is 180s, the temperature in the furnace is 240°C, the gas in the furnace is 0 sccm, the pressure in the furnace is 0 mtorr, and the auxiliary heating is turned on with the time of 180s and the temperature of 280°C.

[0059] ⑤ Leakage detection: Close the main pumping valve and check whether the pressure in the furnace rises from low pressure at a normal rate (leakage rate standard

[0060] ≤120mtorr / min);

[0061] The time setting for this step is 30 seconds, the temperature in the furnace is 240°C, the gas in the furnace is 0 sccm, and the pressure in the furnace is 10,000 mtorr.

[0062] ⑥ Vacuuming: Open the main pumping valve to pump the recovered furnace pressure to a vacuum low pressure state;

[0063] The time setting for this step is 30 seconds, the temperature in the furnace is 240°C, the gas in the furnace is 0 sccm, and the pressure in the furnace is 0 mtorr.

[0064] ⑦ Constant pressure: Open the main pumping valve and introduce the required amount of gas for the deposition step into the furnace. Maintain the required pressure to provide the required atmosphere for the deposition step. At the same time, set the number of ALD deposition cycles to 13 and start the ALD deposition cycle function.

[0065] The time setting for this step is 5s, the temperature in the furnace is 240°C, and the nitrogen flow rate in the furnace is 40,000 sccm.

[0066] Furnace pressure setting: 2000mtorr;

[0067] ⑧ALD deposition - oxygen-containing precursor: Open the main pumping valve and introduce the required amount of gas into the furnace. Maintain the pressure to the required pressure, provide the required atmosphere, and deposit the film.

[0068] The time setting for this step is 15 seconds, the temperature in the furnace is 240°C, the nitrogen flow rate in the furnace is 40,000 sccm, the water vapor flow rate is 500 sccm, the argon flow rate is 500 sccm, and the pressure in the furnace is 2000 mtorr.

[0069] ⑨ Cleaning: Open the main pumping valve and introduce nitrogen to purge the furnace tube under vacuum and low pressure;

[0070] The time setting for this step is 18 seconds, the temperature zone in the furnace is 240°C, the nitrogen flow rate in the furnace is 30,000 sccm, and the pressure in the furnace is 0 mtorr.

[0071] ⑩ Vacuuming: Open the main pumping valve to pump the recovered furnace pressure back to a vacuum low-pressure state;

[0072] The time setting for this step is 20 seconds, the temperature in the furnace is 240°C, the gas in the furnace is 0 sccm, and the pressure in the furnace is 0 mtorr.

[0073] ALD deposition - aluminum-containing precursor: Open the main pump valve, introduce the required gas volume for the deposition step into the furnace, maintain the pressure constant to the required pressure for the deposition step, provide the required atmosphere for the deposition step, start the ALD cycle setting, and deposit the film;

[0074] Among them, the time setting of this step is: 12s, the temperature in the furnace is set to: 240℃, the argon flow rate in the furnace is set to: 2500sccm, the pressure in the furnace is set to: 1400mtorr, the TMA (trimethylaluminum) aluminum-containing precursor flow rate is set to: 2500sccm, and the nitrogen flow rate in the furnace is set to: 32000sccm.

[0075] Cleaning: Open the main pumping valve and introduce nitrogen gas to purge the furnace tube under vacuum and low pressure;

[0076] The time setting for this step is 20 seconds, the temperature zone in the furnace is 240°C, the nitrogen flow rate in the furnace is 30,000 sccm, and the pressure in the furnace is 0 mtorr.

[0077] Vacuuming: Open the main pumping valve to pump the recovered furnace pressure back to a vacuum low-pressure state, and set the ALD deposition cycle end function;

[0078] The time setting for this step is 25 seconds, the temperature in the furnace is 240°C, the gas in the furnace is 0 sccm, and the pressure in the furnace is 0 mtorr.

[0079] S2. Using plasma enhanced chemical vapor deposition (PECVD) technology, an aluminum nitride film layer is formed on the surface of the aluminum oxide film layer facing away from the silicon substrate in a step-by-step power mode of low and high power, specifically including:

[0080] ① Cleaning: Open the main pumping valve and introduce nitrogen to purge the furnace tube under vacuum and low pressure;

[0081] The time setting for this step is 20 seconds, the temperature zone in the furnace is 240°C, the nitrogen flow rate in the furnace is 30,000 sccm, and the pressure in the furnace is 0 mtorr.

[0082] ② Vacuuming: Open the main pumping valve to pump the recovered furnace pressure back to a vacuum low-pressure state;

[0083] The time setting for this step is 20 seconds, the temperature in the furnace is 240°C, the gas in the furnace is 0 sccm, and the pressure in the furnace is 0 mtorr.

[0084] ③ Constant pressure: Open the main pumping valve and let the gas required for the deposition step flow into the furnace until the pressure is constant to the required pressure, providing the atmosphere required for the deposition step;

[0085] The time setting for this step is 30 seconds, the temperature in the furnace is 240°C, the flow rate of ammonia in the furnace is 4000 sccm, the flow rate of TMA aluminum-containing precursor is 1500 sccm, and the pressure in the furnace is 1700 mtorr.

[0086] ④ Low-power PECVD preparation of the first aluminum nitride film layer: open the main pumping valve, introduce the gas required for the deposition step into the furnace, maintain the pressure constant to the required pressure, and provide the required atmosphere for the deposition step; turn on the RF power supply to glow ionize the mixed gas and deposit the film;

[0087] Among them, the time setting of this step is: 30s, the temperature setting in the furnace is: 240℃, the flow rate of ammonia in the furnace is: 4000sccm, the flow rate of TMA (trimethylaluminum) aluminum-containing precursor is: 1500sccm, the pressure setting in the furnace is: 1700mtorr, the power setting is: 4500W, the pulse on setting is: 40ms, and the pulse off setting is: 2800ms;

[0088] ⑤ Preparation of the second aluminum nitride film layer by high-power PECVD: Open the main pumping valve, introduce the gas required for the deposition step into the furnace, and maintain the pressure constant to provide the required atmosphere for the deposition step; turn on the RF power supply to glow ionize the mixed gas and deposit the film;

[0089] Among them, the time setting of this step is: 75s, the temperature setting in the furnace is: 240℃, the flow rate of ammonia in the furnace is: 4000sccm, the flow rate of TMA (trimethylaluminum) aluminum-containing precursor is: 1500sccm, the pressure setting in the furnace is: 1700mtorr, the power setting is: 12500W, the pulse on setting is: 40ms, and the pulse off setting is: 2800ms;

[0090] ⑥ Vacuuming: Open the main pumping valve to pump the pressure in the furnace after deposition to a vacuum low pressure state;

[0091] The time setting for this step is 30 seconds, the temperature in the furnace is 240°C, all gases in the furnace are set to 0 sccm, and the pressure in the furnace is set to 0 mtorr.

[0092] ⑦ Cleaning: Open the main pumping valve and introduce nitrogen to purge the furnace tube under vacuum and low pressure;

[0093] The time setting for this step is 30 seconds, the temperature in the furnace is 240°C, the nitrogen flow rate in the furnace is 30,000 sccm, and the pressure in the furnace is 0 mtorr.

[0094] ⑧ Back pressure: Close the main pumping valve and introduce nitrogen gas under vacuum low pressure to raise the pressure to normal pressure;

[0095] The time setting for this step is 120 seconds, the temperature in the furnace is 240°C, the nitrogen flow rate in the furnace is 50,000 sccm, and the pressure in the furnace is 10,000 mtorr.

[0096] ⑨ Boat removal: Take the deposited graphite boat from the heating furnace tube to the paddle;

[0097] Among them, the step time is set to 120s, the furnace temperature is set to 240℃, the nitrogen flow rate is set to 50000sccm, and the furnace pressure is set to 10000mtorr;

[0098] ⑩ Boat under paddle: Use a robot to grab the graphite boat loaded with silicon substrate after deposition from the paddle and place it on the docking platform.

[0099] The solar cell passivation structure prepared above includes an aluminum oxide film layer provided on a silicon substrate and an aluminum nitride film layer provided on a surface of the aluminum oxide film layer facing away from the silicon substrate, the aluminum nitride film layer includes a first aluminum nitride film layer and a second aluminum nitride film layer, the first aluminum nitride film layer is sandwiched between the second aluminum nitride film layer and the aluminum oxide film layer, wherein the first aluminum nitride film layer and the second aluminum nitride film layer are prepared by a PECVD process, and the deposition power of the first aluminum nitride film layer is less than the deposition power of the second aluminum nitride film layer.

[0100] After testing, the average thickness of the aluminum nitride film layer in the passivation structure of the obtained solar cell (used to reflect the average value of the overall film thickness) is 3.81nm, and the inter-sheet uniformity (used to reflect the difference in film thickness data between all the test sheets at that time. The lower the uniformity, the smaller the difference in film thickness data between sheets, and the smaller the difference in corresponding battery sheets) is 14.16%; among them, the average thickness of the first aluminum nitride film layer is 0.58nm, and the inter-sheet uniformity is 12.76%; the average thickness of the second aluminum nitride film layer is 3.31nm, and the inter-sheet uniformity is 6.62%.

[0101] Example 2

[0102] This embodiment proposes a method for preparing a passivation structure of a solar cell, which differs from Example 1 in that: in this embodiment, PECVD technology is used to prepare an aluminum nitride film layer on the surface of the aluminum oxide film layer facing away from the silicon substrate through a low- and high-step power mode. The step time setting for preparing the first aluminum nitride film layer by low-power PECVD is adjusted from 30s in Example 1 to 40s, and the step time setting for preparing the second aluminum nitride film layer by high-power PECVD is adjusted from 75s in Example 1 to 110s. The rest is the same as Example 1.

[0103] The solar cell passivation structure produced above includes an aluminum oxide film layer disposed on a silicon substrate and an aluminum nitride film layer disposed on the surface of the aluminum oxide film layer facing away from the silicon substrate. The aluminum nitride film layer comprises a first aluminum nitride film layer and a second aluminum nitride film layer, with the first aluminum nitride film layer sandwiched between the second aluminum nitride film layer and the aluminum oxide film layer. Testing showed that the average thickness of the aluminum nitride film layer in the resulting solar cell passivation structure was 4.57 nm, with an inter-sheet uniformity of 2.41% (less than 5%), indicating good overall uniformity.

[0104] Example 3

[0105] This embodiment proposes a method for preparing a passivation structure of a solar cell, which differs from Example 1 in that: in this embodiment, PECVD technology is used to prepare an aluminum nitride film layer on the surface of the aluminum oxide film layer facing away from the silicon substrate through a low- and high-step power mode. The step time setting for preparing the first aluminum nitride film layer by low-power PECVD is adjusted from 30s in Example 1 to 40s, and the step time setting for preparing the second aluminum nitride film layer by high-power PECVD is adjusted from 75s in Example 1 to 150s. The rest is the same as Example 1.

[0106] The solar cell passivation structure produced above includes an aluminum oxide film layer disposed on a silicon substrate and an aluminum nitride film layer disposed on the surface of the aluminum oxide film layer facing away from the silicon substrate. The aluminum nitride film layer comprises a first aluminum nitride film layer and a second aluminum nitride film layer, with the first aluminum nitride film layer sandwiched between the second aluminum nitride film layer and the aluminum oxide film layer. Testing showed that the average thickness of the aluminum nitride film layer in the resulting solar cell passivation structure was 5.85 nm, with an inter-sheet uniformity of 5.41% (close to 5%), indicating good overall uniformity.

[0107] Example 4

[0108] This embodiment provides a solar cell, the preparation method of which includes the following steps:

[0109] S1. On one side of the silicon substrate in the thickness direction, an emitter, a solar cell passivation structure and a first anti-reflection layer are sequentially prepared from the inside to the outside.

[0110] Specifically, the silicon substrate may be an N-type crystalline silicon substrate, the emitter may be a P-type emitter, and the emitter, solar cell passivation structure, and first anti-reflection layer are disposed on the front surface of the silicon substrate. In other embodiments, the emitter, solar cell passivation structure, and first anti-reflection layer may also be disposed on the back surface of the silicon substrate.

[0111] The preparation of the solar cell passivation structure refers to the preparation method of the solar cell passivation structure in Example 1. Specifically, an aluminum oxide film layer is first prepared on the surface of the emitter facing away from the silicon substrate, and then an aluminum nitride film layer is prepared on the surface of the aluminum oxide film layer facing away from the emitter by using PECVD technology through a low and high step-by-step power mode. The specific operation refers to Example 1 and will not be repeated here.

[0112] S2. On the other side of the silicon substrate in the thickness direction, a tunneling oxide layer, a polysilicon layer, and a second anti-reflection layer are sequentially prepared from the inside to the outside.

[0113] The tunnel oxide layer, the polysilicon layer and the second anti-reflection layer can be prepared using conventional preparation methods, which are not limited thereto.

[0114] S3. Print the front slurry and the back slurry on the first anti-reflection layer setting side and the second anti-reflection layer setting side in the thickness direction of the silicon substrate respectively, and after drying and sintering, obtain the front electrode and the back electrode respectively, completing the preparation of the finished battery.

[0115] Among them, one end of the front electrode is inserted into and penetrates the first anti-reflection layer along the thickness direction of the first anti-reflection layer, electrically connected to the passivation structure of the solar cell, and the other end is exposed on the surface of the cell; one end of the back electrode is inserted into and penetrates the second anti-reflection layer along the thickness direction of the second anti-reflection layer, electrically connected to the polysilicon layer, and the other end is also exposed on the surface of the cell.

[0116] The solar cell structure prepared above is as follows Figure 1As shown, it includes a silicon substrate 11, an emitter 12, a solar cell passivation structure 13, and a first anti-reflection layer 14 arranged in sequence from the inside to the outside on one side of the silicon substrate 11 in the thickness direction, and a tunneling oxide layer 15, a polysilicon layer 16, and a second anti-reflection layer 17 arranged in sequence from the inside to the outside on the other side of the silicon substrate 11 in the thickness direction. The solar cell passivation structure 13 includes an aluminum oxide film layer 131 and an aluminum nitride film layer, wherein the aluminum nitride film layer includes a first aluminum nitride film layer 132 and a second aluminum nitride film layer 133, the aluminum oxide film layer 131 is sandwiched between the emitter 12 and the first aluminum nitride film layer 132, the first aluminum nitride film layer 132 is sandwiched between the aluminum oxide film layer 131 and the second aluminum nitride film layer 133, and the second aluminum nitride film layer 133 is sandwiched between the first aluminum nitride film layer 132 and the first anti-reflection layer 14; the solar cell also includes a front electrode 18 and The back electrode 19; the front electrode 18 is arranged on the side where the first anti-reflection layer 14 is set in the thickness direction of the silicon substrate 11, one end of the front electrode 18 penetrates the first anti-reflection layer 14 and is electrically connected to the second aluminum nitride film layer 133 in the passivation structure 13 of the solar cell, and the other end is exposed on the surface of the solar cell; the back electrode 19 is arranged on the side where the second anti-reflection layer 17 is set in the thickness direction of the silicon substrate 11, one end of the back electrode 19 penetrates the second anti-reflection layer 17 and is electrically connected to the polysilicon layer 16, and the other end is also exposed on the surface of the solar cell.

[0117] Examples 5-6

[0118] Examples 5 and 6 respectively propose a solar cell, which differs from Example 4 in that the preparation process of the solar cell and the preparation of the solar cell passivation structure of Examples 5 and 6 refer to Examples 2 and 3 respectively, and the rest are the same as Example 4.

[0119] Comparative Example 1

[0120] This comparative example proposes a method for preparing a passivation structure of a solar cell, which differs from Example 1 in that: in this comparative example, step S2 of Example 1 is adjusted to use PECVD technology through a low-and-high step-by-step power mode to further prepare an aluminum oxide film layer on the surface of the aluminum oxide film layer facing away from the silicon substrate, to replace the aluminum nitride film layer in Example 1, and the rest is the same as Example 1.

[0121] Specifically, in this comparative example, the introduction of ammonia in steps ③, ④, and ⑤ of step S2 of Example 1 was replaced by the introduction of an equal amount of nitrous oxide, and the rest was the same as in Example 1, thereby first preparing a first aluminum oxide film layer on the surface of the aluminum oxide film layer facing away from the silicon substrate by low-power PECVD, and then preparing a second aluminum oxide film layer on the surface of the first aluminum oxide film layer by high-power PECVD.

[0122] The solar cell passivation structure prepared above includes an aluminum oxide film layer provided on a silicon substrate, and the aluminum oxide film layer includes an aluminum oxide film layer prepared by atomic layer deposition, a first aluminum oxide film layer prepared by low-power PECVD, and a second aluminum oxide film layer prepared by high-power PECVD in sequence along its thickness direction.

[0123] Comparative Example 2

[0124] This comparative example proposes a method for preparing a solar cell passivation structure. This method differs from Example 1 in that: in this example, an aluminum nitride film layer is formed on the surface of the aluminum oxide film layer facing away from the silicon substrate using PECVD technology in a single high-power mode, i.e., the step of preparing the first aluminum nitride film layer using low-power PECVD is omitted. Since the product of power and time represents energy during the deposition of the aluminum nitride film layer using PECVD technology, and the film thickness remains almost unchanged when the total energy value remains unchanged, the total energy value of the high-power PECVD deposition of the aluminum nitride film layer in this example is controlled to be substantially the same as the total energy value of the PECVD deposition of the aluminum nitride film layer in Example 1 (4500*30+12500*75=1072500). The time setting for the high-power PECVD deposition of the aluminum nitride film layer is adjusted from 75 seconds in Example 1 to 85 seconds, and the power setting is 12500W. All other aspects are the same as in Example 1.

[0125] The solar cell passivation structure prepared above includes an aluminum oxide film layer disposed on a silicon substrate and an aluminum nitride film layer disposed on a surface of the aluminum oxide film layer facing away from the silicon substrate.

[0126] Comparative Example 3

[0127] This comparative example proposes a method for preparing a passivation structure of a solar cell, which differs from Example 1 in that: in this example, PECVD technology is used to prepare an aluminum nitride film layer on the surface of the aluminum oxide film layer facing away from the silicon substrate in a single low-power mode, that is, the step of preparing the second aluminum nitride film layer by high-power PECVD is removed, and the total energy value of the low-power PECVD deposition to prepare the aluminum nitride film layer in this example is controlled to be basically the same as the total energy value of the PECVD process for preparing the aluminum nitride film layer in Example 1 (4500*30+12500*75=1072500), the time setting of the low-power PECVD step for preparing the aluminum nitride film layer is adjusted from 75s in Example 1 to 235s, and its power is set to 4500W, and the rest is the same as Example 1.

[0128] The solar cell passivation structure prepared above includes an aluminum oxide film layer disposed on a silicon substrate and an aluminum nitride film layer disposed on a surface of the aluminum oxide film layer facing away from the silicon substrate.

[0129] Comparative Examples 4 to 6

[0130] Comparative Examples 4 to 6 propose a solar cell, which differs from Example 4 in that the preparation process of the solar cell in Comparative Examples 4 to 6 and the preparation of the solar cell passivation structure refer to Comparative Examples 1 to 3 respectively, and the rest are the same as Example 4.

[0131] Performance Testing

[0132] The efficiency (Eta), open circuit voltage (Uoc), short circuit current (Isc) and fill factor (FF) of the solar cells of Examples 4 to 6 and Comparative Examples 4 to 6 were tested using a solar cell test system (manufacturer: Lixit Optoelectronics Technology Co., Ltd., model: PSS-IV-EL). The test environment temperature was 23.2°C and the humidity was 52%. The test results are shown in Table 1.

[0133] Table 1

[0134] solar cells Eta (%) Uoc(V) Isc(A) FF(%) Example 4 26.243 0.7376 13.935 85.462 Example 5 26.254 0.7375 13.942 85.482 Example 6 26.267 0.7376 13.936 85.562 Comparative Example 4 26.208 0.7373 13.929 85.394 Comparative Example 5 26.165 0.7346 13.923 85.416 Comparative Example 6 26.199 0.7361 13.936 85.449

[0135] According to Table 1 above, by comparing Example 4 and Comparative Example 4, it can be seen that, compared with Comparative Example 4, Example 4 has an efficiency that is 0.035% higher, an open circuit voltage that is 0.0003 V (i.e., 0.3 mV) higher, a short circuit current that is 0.006 A (i.e., 6 mA) higher, and a fill factor that is 0.068% higher. That is, Example 4 has a higher open circuit voltage and fill factor than Comparative Example 4. This demonstrates that the solar cell in Example 4 uses a low- and high-step power mode to prepare a solar cell passivation structure composed of an aluminum nitride film layer on an aluminum oxide film layer by PECVD, and its passivation effect is better than the passivation effect of the passivation structure constructed by the aluminum oxide film layer in Comparative Example 4. That is, the aluminum nitride film layer and the aluminum oxide film layer in Example 4 are composited to enhance the passivation performance of the battery product and improve the photoelectric conversion efficiency.

[0136] Comparing Examples 5 and 6 with Comparative Example 4, it can be seen that Examples 5 and 6 have higher open-circuit voltage and fill factor than Comparative Example 4. This demonstrates that the passivation properties of the solar cell passivation structure constructed from a composite of aluminum oxide and aluminum nitride layers in Examples 5 and 6 are superior to the passivation effect of the passivation structure constructed from multiple aluminum oxide layers in Comparative Example 4. In other words, the effectiveness of the above solar cell passivation structure is mainly reflected in the improvement of the cell open-circuit voltage and fill factor, which jointly influence and ultimately reflect the efficiency improvement. Comparing Examples 5 and 6, it can be seen that the solar cell of Example 5, which has a shorter high-power PECVD deposition time for preparing the aluminum nitride film and a lower aluminum nitride film thickness, exhibits lower efficiency, open-circuit voltage, and fill factor than the solar cell of Example 6, which has a longer high-power PECVD deposition time for preparing the aluminum nitride film and a higher aluminum nitride film thickness. This shows that in the solar cell passivation structure constructed from a composite of aluminum oxide and aluminum nitride layers, within the effective film thickness range, increasing the aluminum nitride film thickness has a positive effect on the passivation effect. Compared with Examples 4 to 6, the open-circuit voltage of the solar cell in Example 5 is slightly lower than that in Example 4, which is caused by production and testing errors. In addition, the short-circuit current of the solar cells in Examples 4 to 6 fluctuates with the increase of the deposition time of the aluminum nitride film layer in the passivation structure. This is because the main influencing factors of the short-circuit current are in the emitter and first anti-reflection layer processes, and are not strongly correlated with the passivation structure.

[0137] By comparing Example 4 and Comparative Example 5, it can be seen that Example 4 is 0.078% more efficient than Comparative Example 5, wherein the open circuit voltage is 0.003 V (i.e., 3 mV) higher, the short circuit current is 0.012 A (i.e., 12 mA) higher, and the fill factor is 0.046% higher, that is, Example 4 has higher open circuit voltage and fill factor than Comparative Example 5. This reflects that the solar cell in Example 4 uses a low- and high-step power mode of PECVD on the aluminum oxide film layer to prepare a solar cell passivation structure composed of an aluminum nitride film layer. The passivation effect is better than the passivation effect of the passivation structure constructed by the single high-power prepared aluminum nitride film layer in the solar cell of Comparative Example 5. That is, the aluminum nitride film layer and the aluminum oxide film layer in the solar cell of Example 4 are composited, which can enhance the passivation performance of the battery product and improve the photoelectric conversion efficiency.

[0138] By comparing Example 4 and Comparative Example 6, it can be seen that Example 4 has an efficiency higher than that of Comparative Example 6 by 0.044%, wherein the open circuit voltage is 0.0015 (i.e., 1.5 mV) higher, and the fill factor is 0.013% higher, that is, Example 4 has higher open circuit voltage and fill factor than Comparative Example 6. This reflects that the solar cell in Example 4 uses a low-and-high step-by-step power mode to prepare a solar cell passivation structure composed of an aluminum nitride film layer on an aluminum oxide film layer by PECVD, and its passivation effect is better than the passivation effect of the passivation structure constructed by a single low-power prepared aluminum nitride film layer in the solar cell of Comparative Example 6, that is, the aluminum nitride film layer and the aluminum oxide film layer in the solar cell of Example 4 are composited, which can enhance the passivation performance of the battery product and improve the photoelectric conversion efficiency.

[0139] The above-described embodiments merely illustrate several implementations of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, and all such variations and improvements fall within the scope of protection of the present invention.

Claims

1. A method for preparing a solar cell passivation structure, characterized in that: The following steps are involved: preparing an aluminum oxide film layer on a substrate; An aluminum nitride film layer is prepared on the surface of the aluminum oxide film layer facing away from the substrate using plasma enhanced chemical vapor deposition technology, including: using plasma enhanced chemical vapor deposition technology, at a first power, preparing a first aluminum nitride film layer on the surface of the aluminum oxide film layer facing away from the substrate, and then at a second power, preparing a second aluminum nitride film layer on the surface of the first aluminum nitride film layer facing away from the aluminum oxide film layer, wherein the first power is less than the second power.

2. The method for preparing a solar cell passivation structure according to claim 1, wherein: The first power is less than or equal to 6000W; and / or the second power is greater than 6000W.

3. The method for preparing a solar cell passivation structure according to claim 2, wherein: The thickness of the first aluminum nitride film layer is 0.1 nm to 2.5 nm; and / or the thickness of the second aluminum nitride film layer is 1 nm to 6 nm.

4. The method for preparing a solar cell passivation structure according to claim 3, wherein: The total thickness of the first aluminum nitride film layer and the second aluminum nitride film layer is 3 nm to 7 nm; and / or the thickness of the first aluminum nitride film layer is less than the thickness of the second aluminum nitride film layer.

5. The method for preparing a solar cell passivation structure according to any one of claims 1 to 4, characterized in that: The aluminum oxide film layer is prepared by atomic layer deposition technology; and / or the thickness of the aluminum oxide film layer is 1nm to 3nm.

6. A solar cell passivation structure, characterized in that: The solar cell passivation structure is prepared by the preparation method of any one of claims 1 to 5.

7. A method for preparing a solar cell passivation structure according to any one of claims 1 to 5 or use of the solar cell passivation structure according to claim 6 in preparing a solar cell.

8. A solar cell, characterized in that: The solar cell passivation structure comprises the solar cell passivation structure according to claim 6.

9. The solar cell according to claim 8, characterized in that Taking the substrate as a reference, the solar cell comprises, from the inside to the outside, an emitter, the solar cell passivation structure, and a first anti-reflection layer on one side of the substrate in the thickness direction; Taking the substrate as a reference, the solar cell includes, from the inside to the outside, a tunneling oxide layer, a polysilicon layer, and a second anti-reflection layer on the other side of the substrate in the thickness direction.

10. A method for preparing a solar cell, characterized in that: The following steps are involved: On one side of the substrate in the thickness direction, an emitter, a solar cell passivation structure and a first anti-reflection layer are sequentially prepared from the inside to the outside; On the other side of the substrate in the thickness direction, a tunnel oxide layer, a polysilicon layer, and a second anti-reflection layer are sequentially formed from the inside to the outside; preparing a first electrode on the side where the first anti-reflection layer is provided in the thickness direction of the substrate; preparing a second electrode on the side where the second anti-reflection layer is provided in the thickness direction of the substrate to prepare a solar cell; Among them, the preparation of the solar cell passivation structure includes: preparing an aluminum oxide film layer on the surface of the emitter facing away from the substrate; and then using plasma enhanced chemical vapor deposition technology to prepare an aluminum nitride film layer on the surface of the aluminum oxide film layer facing away from the emitter, specifically including: using plasma enhanced chemical vapor deposition technology, at a first power, preparing a first aluminum nitride film layer on the surface of the aluminum oxide film layer facing away from the emitter, and then at a second power, preparing a second aluminum nitride film layer on the surface of the first aluminum nitride film layer facing away from the aluminum oxide film layer, wherein the first power is less than the second power.

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