Passivation contact structure and preparation method thereof, solar cell and electric device
By stacking tunneling oxide layers and doped polysilicon material layers on the substrate of the solar cell, combining fleece making and modification treatments to form a passivation contact structure, the problems of impurities and long-band light absorption in crystalline silicon solar cells are solved, and the problem of impurities and long-band light absorption in crystalline silicon solar cells is improved. Short circuit current and battery efficiency.
Patent Information
- Application Number
- CN202310722302.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-06-16
- Publication Date
- 2024-12-17
AI Technical Summary
The efficiency of crystalline silicon solar cells is affected by impurities and defects, and the TOPCon structure has insufficient light absorption in the long-band band, resulting in weakening of short-flow response.
The preparation method of a passivation contact structure is adopted, including stacking the first and second tunneling oxide layers, doped polysilicon material layer and dielectric layer on the substrate, and removing the second dielectric layer through fleece making and modification treatment. Form a suede structure to reduce long-band light absorption.
While maintaining the passivation advantage, the absorption of long-band light is reduced, the short-circuit current is increased, and the light refractive loss caused by the back design of the battery is balanced.
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Figure CN119153575A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of battery technology, and in particular to a passivation contact structure and a preparation method thereof, a solar cell and an electrical device. Background Art
[0002] As the global energy system is transforming towards low-carbonization, the large-scale use of renewable energy and the clean and low-carbonization of conventional energy will be the basic trend. Accelerating the development of renewable energy has become the mainstream direction of global energy transformation, and photovoltaic power generation is a key area. Solar cells are mainly large-area semiconductor photodiodes, which are electronic components that directly convert sunlight energy into electrical energy due to the photovoltaic effect. They can use the photoelectric effect after photoelectric materials absorb light energy to convert light energy into electrical energy. Therefore, solar power generation is also called photovoltaic power generation.
[0003] Tunneling oxide passivation contact (TOPCon) is a passivation structure for crystalline silicon solar cells. It consists of an ultra-thin layer of silicon oxide and a layer of heavily doped polysilicon. It is mainly used for the passivation of the back surface of the cell. It can achieve excellent surface passivation and selective collection of carriers. The conversion efficiency of crystalline silicon solar cells prepared with it has exceeded 25.7%. However, compared with the theoretical limit efficiency, there is still a lot of room for improvement. Impurities and defects inside crystalline silicon and metal-semiconductor contact recombination losses on the front surface of the cell are the main factors restricting the continued improvement of cell efficiency. Because of its unique structure, TOPCon has the possibility of removing impurities, and the addition of some elements to its polysilicon layer can change its optical properties. Therefore, it is not only used in TOPCon cells, but also in all-back electrode contact cells (IBC cells). Either to accommodate more impurities or to provide a larger printing window for screen printing, the thickness of the doped polysilicon layer is often between 150 and 200nm, but at this thickness, the polysilicon layer will cause a large amount of long-wave absorption, which will weaken the short-current response of the cell. Summary of the invention
[0004] Based on this, the present application provides a passivation contact structure and a preparation method thereof, a solar cell and an electrical device, which can ensure that the passivation contact structure has the advantages of field passivation while reducing its absorption of long-wavelength light and improving short-current response.
[0005] The present application provides a method for preparing a passivation contact structure, comprising the following steps:
[0006] A prefabricated structure is provided, the prefabricated structure comprising: a substrate, a first tunneling oxide layer, a first doped polysilicon material layer and a first dielectric layer stacked in sequence on a surface of one side of the substrate, and a second tunneling oxide layer, a second doped polysilicon material layer and a second dielectric layer stacked in sequence on a surface of another side of the substrate, wherein the thickness of the first doped polysilicon material layer is 120nm to 200nm. The second dielectric layer in the prefabricated structure is removed to prepare a base structure;
[0007] The base structure is sequentially placed in a first texturing solution for a first texturing treatment, placed in a hydrofluoric acid solution for a modification treatment, and placed in a second texturing solution for a second texturing treatment to prepare a passivation contact structure, wherein the passivation contact structure includes a sequentially stacked velvet substrate, the first tunneling oxide layer, and a doped polysilicon layer,
[0008] The first texturing treatment lasts for 40s to 420s, and the first texturing solution comprises, by mass percentage, 1% to 5.5% of a monobasic strong base, 0.3% to 2.5% of an additive, and 92% to 98.7% of a solvent;
[0009] The treatment time in the modification treatment is 5s to 220s;
[0010] The treatment time of the second texturing treatment is 40s to 220s, and the composition of the second texturing solution includes, by mass percentage, 0.5% to 5% of a monobasic strong base, 1% to 3.5% of an additive and 91.5% to 98.5% of a solvent.
[0011] In one embodiment, the conditions of the first texturing treatment and the second texturing treatment independently include: a treatment temperature of 70°C to 90°C.
[0012] In one of the embodiments, the modification treatment conditions further include: the mass percentage of hydrofluoric acid in the hydrofluoric acid solution is 8% to 22%.
[0013] In one embodiment, the additive includes one or more of a texturing additive and a polishing additive.
[0014] In one embodiment, the monobasic strong base includes one or more of potassium hydroxide and sodium hydroxide.
[0015] In one embodiment, the method of removing the second dielectric layer includes: chain etching.
[0016] Furthermore, the present application also provides a passivation contact structure, which is prepared according to the above-mentioned preparation method.
[0017] In one of the embodiments, the thickness of the doped polysilicon layer is 70 nm to 130 nm.
[0018] The present application also provides a solar cell, comprising the passivation contact structure as described above.
[0019] The present application also provides an electrical device, comprising the solar cell as described above as a power source.
[0020] The above-mentioned passivation contact structure is for a dielectric layer formed on the doped polysilicon material layer when the base structure is subjected to doping treatment. After removing one side of the dielectric layer, the doped polysilicon layer with a thickness within a suitable range is prepared by texturing and polishing the front and back sides of the substrate. Both sides of the passivation contact structure have a velvet structure. While retaining the passivation advantage of the doped polycrystalline layer, the passivation contact structure reduces the absorption of long-wavelength light and thereby increases the short-circuit current, and further balances the light refraction loss caused by the velvet design on the back side of the battery. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 A schematic diagram of the passivation contact structure provided for this application;
[0022] Figure 2 A schematic diagram of a process for preparing a passivation contact structure according to an embodiment of the present application;
[0023] Figure 3 A schematic diagram of a process for preparing a passivation contact structure according to an embodiment of the present application;
[0024] Figure 4 A schematic diagram of a process for preparing a passivation contact structure according to an embodiment of the present application;
[0025] Figure 5 This is a schematic diagram of the solar cell structure during the test of this application;
[0026] The reference numerals are described as follows:
[0027] 10: passivation contact structure; 100: velvet substrate; 101: substrate; 110: first tunneling oxide layer; 120: doped polysilicon layer; 121: first doped polysilicon material layer; 130: first dielectric layer; 140: second tunneling oxide layer; 150: second doped polysilicon material layer; 160: second dielectric layer; 20: solar cell; 210: tunneling oxide layer; 220: N-type polysilicon layer; 230: first aluminum oxide layer; 231: second aluminum oxide layer; 240: first silicon nitride layer; 241: second silicon nitride layer; 250: first electrode; 260: second electrode. DETAILED DESCRIPTION
[0028] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present application are given in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present application more thorough and comprehensive.
[0029] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the invention, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. In the description of the present application, the meaning of "several" is at least one, such as one, two, etc., unless otherwise clearly and specifically defined.
[0030] The words "preferably", "more preferably" and the like in this application refer to embodiments of the present application that may provide certain beneficial effects in certain circumstances. However, other embodiments may also be preferred under the same circumstances or in other circumstances. In addition, the statement of one or more preferred embodiments does not imply that other embodiments are not available, nor is it intended to exclude other embodiments from the scope of this application.
[0031] When a numerical range is disclosed herein, the above range is considered to be continuous and includes the minimum and maximum values of the range, as well as every value between such minimum and maximum values. Further, when a range refers to an integer, every integer between the minimum and maximum values of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be combined. In other words, unless otherwise indicated, all ranges disclosed herein should be understood to include any and all subranges included therein.
[0032] When describing positional relationships, unless otherwise specified, when an element such as a layer, film, or substrate is referred to as being "on" another film layer, it can be directly on the other film layer or there can be intervening film layers. Further, when a layer is referred to as being "under" another layer, it can be directly below or there can be one or more intervening layers. It is also understood that when a layer is referred to as being "between" two layers, it can be the only layer between the two layers, or there can be one or more intervening layers.
[0033] Where “including,” “having,” and “comprising” are used herein, it is intended to cover a non-exclusive inclusion, and another component may also be added unless explicit limiting terms such as “only,” “consisting of,” etc. are used.
[0034] Unless mentioned to the contrary, terms in the singular may include plural forms and should not be construed as being one in number.
[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art to which the present application belongs. The terms used herein in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.
[0036] This application provides a Figure 1 The method for preparing the passivation contact structure 10 shown, wherein the passivation contact structure 10 includes a velvet substrate 100, a first tunneling oxide layer 110, and a doped polysilicon layer 120 stacked in sequence, includes the following steps:
[0037] A prefabricated structure is provided, the prefabricated structure comprising: a substrate 101, a first tunneling oxide layer 110, a first doped polysilicon material layer 121 and a first dielectric layer 130 stacked in sequence on a surface of one side of the substrate 101, and a second tunneling oxide layer 140, a second doped polysilicon material layer 150 and a second dielectric layer 160 stacked in sequence on a surface of the other side of the substrate 101, the first doped polysilicon material layer 121 having a thickness of 120 nm to 200 nm, and the second dielectric layer 160 in the prefabricated structure is removed to prepare a base structure;
[0038] The base structure is sequentially placed in a first texturing solution for a first texturing treatment, placed in a hydrofluoric acid solution for a modification treatment, and placed in a second texturing solution for a second texturing treatment to prepare a passivation contact structure 10, which includes a sequentially stacked textured substrate 100, a first tunneling oxide layer 110, and a doped polysilicon layer 120.
[0039] The first texturing treatment lasts for 40s to 420s, and the first texturing solution comprises, by mass percentage, 1% to 5.5% of a monobasic strong base, 0.3% to 2.5% of an additive, and 92% to 98.7% of a solvent.
[0040] The processing time in the modification process is 5s to 220s;
[0041] The treatment time of the second texturing treatment is 40s to 220s, and the composition of the second texturing solution includes, by mass percentage, 0.5% to 5% of a monobasic strong base, 1% to 3.5% of an additive and 91.5% to 98.5% of a solvent.
[0042] It can be understood that the first tunneling oxide layer 110 and the first doped polysilicon material layer 121 can be prepared by but not limited to a low pressure chemical vapor deposition (LPCVD) method. Furthermore, the second tunneling oxide layer 140 and the second doped polysilicon material layer 150 in the prefabricated structure are formed simultaneously when the first tunneling oxide layer 110 and the first doped polysilicon material layer 121 are formed respectively by a single insertion method during preparation, and the first dielectric layer 130 forms a new material layer when a doping treatment is performed in a double insertion form during the process of forming the first doped polysilicon material layer 121, and the second dielectric layer 160 is produced by wrap-around plating when forming the first dielectric layer 130.
[0043] In a specific example, the thickness of the first dielectric layer 130 is 30 nm to 40 nm. Specifically, the thickness of the first dielectric layer 130 may be, but is not limited to, 30 nm, 31 nm, 32 nm, 33 nm, 34 nm, 35 nm, 36 nm, 37 nm, 38 nm, 39 nm or 40 nm.
[0044] Furthermore, the material of the first tunnel oxide layer 110 and the material of the second tunnel oxide layer 140 include silicon oxide.
[0045] In a specific example, the doping method is selected from low pressure chemical vapor deposition or plasma enhanced chemical vapor deposition.
[0046] Specifically, the step of doping treatment includes: diffusing the first polysilicon material in an atmosphere of oxygen and a gas source containing a doping element at a temperature of 760° C. to 1120° C. Further, the doping element may be, but not limited to, phosphorus or boron. It can be understood that the gas source containing the doping element may be, but not limited to, phosphorus oxychloride (POCl3) or boron chloride (BCl3). That is, the first dielectric layer 1300 and the second dielectric layer 160 are phosphosilicate glass layers or borosilicate glass layers.
[0047] It can be understood that the conductivity type of the substrate 101 and the conductivity type of the doped polysilicon layer 120 can be the same or opposite.
[0048] In a specific example, the conditions of the first texturing treatment and the second texturing treatment independently include: the treatment temperature is 70°C to 90°C.
[0049] Furthermore, the conditions for the first texturing treatment include: placing the base structure in a first texturing liquid for the first texturing treatment, the composition of the first texturing liquid includes, by mass percentage, 1.5% to 5% of a monobasic strong base, 0.5% to 2% of an additive and 93% to 98% of a solvent, the time for the first texturing treatment is 50s to 400s, and the temperature for the first texturing treatment is 75°C to 85°C.
[0050] Specifically, the time of the first texturing treatment may be but is not limited to 50s, 90s, 130s, 170s, 200s, 220s, 240s, 260s, 280s, 300s, 320s, 340s, 360s, 380s or 400s, and the temperature of the first texturing treatment may be but is not limited to 75°C, 76°C, 77°C, 78°C, 79°C, 80°C, 81°C, 82°C, 83°C, 84°C or 85°C.
[0051] In a specific example, the modification treatment conditions also include: the mass percentage of hydrofluoric acid in the hydrofluoric acid solution is 8% to 22%.
[0052] It can be understood that after the base structure is subjected to the first texturing treatment, it is placed in a hydrofluoric acid solution for modification treatment for 10s to 200s, wherein the mass percentage of hydrofluoric acid in the hydrofluoric acid solution is 10% to 20%, and the hydrofluoric acid is specifically an aqueous solution of hydrofluoric acid.
[0053] Specifically, the mass percentage of hydrofluoric acid in the hydrofluoric acid solution may be, but is not limited to, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19% or 20%, and the time of the modification treatment may be, but is not limited to, 10s, 20s, 30s, 40s, 50s, 60s, 70s, 80s, 90s, 100s, 110s, 120s, 130s, 140s, 150s, 160s, 170s, 180s, 190s or 200s.
[0054] Furthermore, the conditions for the second texturing treatment include: the composition of the second texturing liquid includes 1% to 4.5% of a monobasic strong base, 1.5% to 3% of an additive and 93% to 98% of a solvent in mass percentage after the base structure has been subjected to the first texturing treatment and the modification treatment, the time for the second texturing treatment is 50s to 200s, and the temperature for the second texturing treatment is 75°C to 85°C.
[0055] Specifically, the time of the second texturing treatment may be but is not limited to 50s, 60s, 70s, 80s, 90s, 100s, 110s, 120s, 130s, 140s, 150s, 160s, 170s, 180s, 190s or 200s, and the temperature of the second texturing treatment may be but is not limited to 75℃, 76℃, 77℃, 78℃, 79℃, 80℃, 81℃, 82℃, 83℃, 84℃ or 85℃.
[0056] In a specific example, the monobasic strong base may include, but is not limited to, one or more of potassium hydroxide and sodium hydroxide.
[0057] Furthermore, the solvent may include, but is not limited to, water. It is to be understood that the water here refers to deionized water.
[0058] In a specific example, the additive includes one or more of a texturing additive and a polishing additive.
[0059] Specifically, the texturing additives include surfactants, texturing catalysts, texturing corrosion inhibitors, surface defoamers and water, and the polishing additives include surfactants, polishing catalysts and polishing protective agents.
[0060] In a specific example, the method for removing the second dielectric layer 160 includes: chain etching. Specifically, through a chain etcher, the side that does not need to be cleaned is protected by a water film, and the side that needs to be cleaned is contacted with HF for etching. The water film protection surface can avoid HF corrosion.
[0061] Furthermore, the present application also provides a passivation contact structure 10, which is manufactured according to the above-mentioned manufacturing method.
[0062] In a specific example, the thickness of the doped polysilicon layer 120 is 70 nm to 130 nm. Specifically, the thickness of the doped polysilicon layer 120 may be, but is not limited to, 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm or 130 nm.
[0063] Further, the thickness of the first tunnel oxide layer 110 is 1.2 nm to 2 nm. Specifically, the thickness of the first tunnel oxide layer 110 may be, but is not limited to, 1.2 nm, 1.3 nm, 1.4 nm, 1.5 nm, 1.6 nm, 1.7 nm, 1.8 nm, 1.9 nm or 2 nm.
[0064] The above-mentioned passivation contact structure 10 is for a dielectric layer formed on the doped polysilicon material layer when the base structure is subjected to doping treatment. After removing one side of the dielectric layer, a doped polysilicon layer 120 with a thickness within a suitable range is prepared by performing texturing and polishing modification treatments on the front and back sides of the substrate 101. The passivation contact structure 10 has a texturing structure on both sides. While retaining the passivation advantage of the doped polycrystalline layer, the passivation contact structure 10 reduces the absorption of long-wavelength light and thereby increases the short-circuit current, and further balances the light refraction loss caused by the texturing design.
[0065] Understandably, Figure 2 to Figure 4 There are three situations in the preparation method of the passivation contact structure 10, but in the end, the following can be prepared: Figure 1 A passivation contact structure 10 is shown.
[0066] The present application also provides a solar cell, comprising the above passivation contact structure 10. The solar cell that can use the above passivation contact structure 10 can include but is limited to an all-back contact cell (IBC cell) and a tunnel oxide layer passivation contact cell (TOPCon cell).
[0067] The present application also provides an electrical device, comprising the solar cell as described above as a power source.
[0068] Furthermore, an electrical device is provided, including the above-mentioned solar cell as a power source. It can be understood that the above-mentioned electrical device may include but is not limited to transformers, reactors, capacitors, combined electrical appliances, circuit breakers, mutual inductors, lightning arresters, coupling capacitors, transmission lines, power cables, grounding devices, generators, phase regulators, motors, closed busbars and thyristors.
[0069] The following specific examples are provided to further illustrate the passivation contact structure and the preparation method of the present application. The raw materials involved in the following specific embodiments, unless otherwise specified, can all be sourced from the market. The additives were purchased from Tuobang with the brand EP12V88.
[0070] Example 1
[0071] The present embodiment provides a passivation contact structure, the preparation steps of which include: providing a prefabricated structure, the prefabricated structure including: a substrate, a first tunneling oxide layer, a first doped polysilicon material layer and a first dielectric layer stacked in sequence on a surface of one side of the substrate, and a second tunneling oxide layer, a second doped polysilicon material layer and a second dielectric layer stacked in sequence on a surface of the other side of the substrate, the first doped polysilicon material layer has a thickness of 200 nm, the first tunneling oxide layer has a thickness of 1.5 nm, and the first dielectric layer has a thickness of 30 nm, and the second dielectric layer is removed by a chain etching method to prepare a base structure;
[0072] The basic structure is sequentially placed in the first texturing liquid for the first texturing treatment, wherein the treatment time of the first texturing treatment is 400 seconds, the treatment temperature is 85° C., and the composition of the first texturing liquid includes 5% sodium hydroxide, 0.5% additives and the rest deionized water in terms of mass percentage;
[0073] Further, the modified product was placed in a hydrofluoric acid solution for 200 seconds, and the mass percentage of hydrofluoric acid in the hydrofluoric acid solution was 20%;
[0074] Finally, the second texturing solution is used for the second texturing treatment. The treatment time of the second texturing treatment is 200s and the treatment temperature is 85°C. The composition of the second texturing solution includes 4.5% sodium hydroxide, 1.5% additives and the rest deionized water in mass percentage to prepare a passivated contact structure. The passivated contact structure includes a substrate, a first tunneling oxide layer and a doped polysilicon layer stacked in sequence.
[0075] Example 2
[0076] The difference between the method for preparing a passivated contact structure in this embodiment and that in Embodiment 1 is that the conditions for the second texturing treatment are different. The conditions for the second texturing treatment in this embodiment include: the treatment time in the second texturing treatment is 50s, the treatment temperature is 75°C, and the composition of the second texturing liquid includes, by mass percentage, 1% sodium hydroxide, 3% additives and the rest deionized water.
[0077] Example 3
[0078] The difference between the method for preparing a passivated contact structure in this embodiment and that in Embodiment 1 is that the modification treatment conditions are different. The modification treatment conditions in this embodiment include: the modification treatment time is 10 s, and the mass percentage of hydrofluoric acid in the hydrofluoric acid solution is 10%.
[0079] Example 4
[0080] The method for preparing the passivated contact structure in this embodiment is different from that in Embodiment 1 in that the conditions for the modification treatment and the conditions for the second texturing treatment are different. The conditions for the modification treatment in this embodiment include: the modification treatment time is 10 seconds, the mass percentage of hydrofluoric acid in the hydrofluoric acid solution is 10%,
[0081] The conditions of the second texturing treatment in this embodiment include: the treatment time in the second texturing treatment is 50s, the treatment temperature is 75°C, and the composition of the second texturing liquid includes 1% sodium hydroxide, 3% additives and the rest deionized water in mass percentage.
[0082] Example 5
[0083] The difference between the method for preparing a passivated contact structure in this embodiment and that in Example 1 is that the conditions for the first texturing treatment are different. The conditions for the first texturing treatment in this embodiment include: a treatment time of 200 s, a treatment temperature of 75°C, and a composition of the first texturing liquid of 1.5% sodium hydroxide, 2% additives and the rest deionized water in mass percentage.
[0084] Example 6
[0085] The method for preparing a passivated contact structure in this embodiment is different from that in Example 2 in that the conditions for the first texturing treatment are different. The conditions for the first texturing treatment in this embodiment include: a treatment time of 50 seconds, a treatment temperature of 75°C, and a composition of the first texturing liquid of 1.5% sodium hydroxide, 2% additives, and the rest deionized water in mass percentage.
[0086] Example 7
[0087] The method for preparing a passivated contact structure in this embodiment is different from that in Example 3 in that the conditions for the first texturing treatment are different. The conditions for the first texturing treatment in this embodiment include: a treatment time of 50 seconds, a treatment temperature of 75°C, and a composition of the first texturing liquid of 1.5% sodium hydroxide, 2% additives, and the rest deionized water in mass percentage.
[0088] Example 8
[0089] The method for preparing a passivated contact structure in this embodiment is different from that in Example 4 in that the conditions for the first texturing treatment are different. The conditions for the first texturing treatment in this embodiment include: a treatment time of 50 seconds, a treatment temperature of 75°C, and a composition of the first texturing solution of 1.5% sodium hydroxide, 2% additives, and the rest deionized water in mass percentage.
[0090] Comparative Example 1
[0091] The method for preparing the passivated contact structure in this comparative example is different from that in Example 1 in that only the following treatments are performed: the conditions of the first texturing treatment and the conditions of the modification treatment are different. The conditions of the first texturing treatment in this comparative example include: the treatment time is 500s, the treatment temperature is 85°C, and the composition of the first texturing solution includes 5% sodium hydroxide, 0.5% additives and the rest deionized water in terms of mass percentage.
[0092] The modification treatment conditions of this comparative example include: the modification treatment time is 200 seconds, and the mass percentage of hydrofluoric acid in the hydrofluoric acid solution is 20%.
[0093] Comparative Example 2
[0094] The method for preparing the passivated contact structure in this comparative example is different from that in Example 2 in that only the following treatments are performed: the conditions of the first texturing treatment and the conditions of the modification treatment are different. The conditions of the first texturing treatment in this comparative example include: the treatment time is 500s, the treatment temperature is 75°C, and the composition of the first texturing solution includes, by mass percentage, 1.5% of sodium hydroxide, 2% of additives, and the rest of deionized water.
[0095] The modification treatment conditions of this comparative example include: the modification treatment time is 200 seconds, and the mass percentage of hydrofluoric acid in the hydrofluoric acid solution is 20%.
[0096] Comparative Example 3
[0097] The difference between the method for preparing the passivated contact structure in this comparative example and that in Example 1 is that the first texturing treatment in this comparative example is the second texturing in Example 1: the time is 200 s, the treatment temperature is 85°C, and the composition of the texturing liquid includes, by mass percentage, 4.5% of sodium hydroxide, 1.5% of additives and the rest deionized water; the second texturing treatment in this comparative example is the first texturing in Example 1: the time is 400 s, the treatment temperature is 85°C, and the composition of the texturing liquid includes, by mass percentage, 5% of sodium hydroxide, 0.5% of additives and the rest deionized water.
[0098] Comparative Example 4
[0099] The difference between the method for preparing the passivated contact structure in this comparative example and Example 1 is that the second texturing time in this comparative example is 400s, the processing temperature is 90°C, and the composition of the texturing liquid includes 6% sodium hydroxide, 1% additives and the rest deionized water in mass percentage.
[0100] Testing methods and test results
[0101] For the solar cells having the passivated contact structures of the above-mentioned embodiments and comparative examples, Figure 5 As shown, the structure of the solar cell includes: a silicon-based substrate 200, a silicon oxide tunneling oxide layer 210, an N-type polysilicon layer 220, a first aluminum oxide layer 230, a first silicon nitride layer 240, a first electrode 250 and a second electrode 260 are sequentially formed on the back of the silicon-based substrate 200, and a second aluminum oxide layer 231 and a second silicon nitride layer 241 are sequentially formed on the front of the silicon-based substrate 200. After three batch experiments, the efficiency (Eta), short-circuit current (Isc), open-circuit voltage (Uoc) and fill factor (FF) of each silicon wafer final product cell are tested. The specific test result data are shown in the following table.
[0102]
[0103]
[0104] Comparison Table 1 shows that from Example 1 to Example 8, compared with the comparative example, the efficiency Eta is improved by 0.1% to 1.51%, and the main improvement comes from Isc, while Uoc has no obvious difference between the example and the comparative example. Although in the example, due to the secondary texturing, there is a certain amount of light loss on the back, the forward gain brought by the thinning of the TOPCon passivation contact structure can still make up for the loss. Among them, Example 1 improves Eta by 0.39% compared with the comparative example, and the influence of more consistent uniformity of the passivation film layer is not ruled out.
[0105] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0106] The above-described embodiments only express several implementation methods of the present application, which is convenient for understanding the technical solutions of the present application in detail, but cannot be understood as limiting the scope of protection of the patent application. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present application, several modifications and improvements can be made, which all belong to the scope of protection of the present application. It should be understood that the technical solutions obtained by those skilled in the art through logical analysis, reasoning or limited experiments on the basis of the technical solutions provided in the present application are all within the scope of protection of the claims attached to the present application. Therefore, the scope of protection of the patent of this application shall be based on the contents of the attached claims, and the description can be used to interpret the contents of the claims.
Claims
1. A method for preparing a passivation contact structure, characterized in that: The following steps are involved: A prefabricated structure is provided, the prefabricated structure comprising: a substrate, a first tunneling oxide layer, a first doped polysilicon material layer and a first dielectric layer stacked in sequence on a surface of one side of the substrate, and a second tunneling oxide layer, a second doped polysilicon material layer and a second dielectric layer stacked in sequence on a surface of the other side of the substrate, the first doped polysilicon material layer having a thickness of 120 nm to 200 nm, and the second dielectric layer in the prefabricated structure is removed to prepare a base structure; The base structure is sequentially placed in a first texturing solution for a first texturing treatment, placed in a hydrofluoric acid solution for a modification treatment, and placed in a second texturing solution for a second texturing treatment to prepare a passivation contact structure, wherein the passivation contact structure includes a sequentially stacked velvet substrate, the first tunneling oxide layer, and a doped polysilicon layer; The first texturing treatment lasts for 40s to 420s, and the first texturing solution comprises, by mass percentage, 1% to 5.5% of a monobasic strong base, 0.3% to 2.5% of an additive, and 92% to 98.7% of a solvent; The treatment time in the modification treatment is 5s to 220s; The treatment time of the second texturing treatment is 40s to 220s, and the composition of the second texturing solution includes, by mass percentage, 0.5% to 5% of a monobasic strong base, 1% to 3.5% of an additive and 91.5% to 98.5% of a solvent.
2. The method for preparing a passivation contact structure according to claim 1, characterized in that: The conditions of the first texturing treatment and the second texturing treatment independently include: the treatment temperature is 70°C to 90°C.
3. The method for preparing a passivation contact structure according to claim 1, characterized in that: The modification treatment conditions also include: the mass percentage of hydrofluoric acid in the hydrofluoric acid solution is 8% to 22%.
4. The method for preparing a passivation contact structure according to claim 1, characterized in that: The additives include one or more of texturing additives and polishing additives.
5. The method for preparing a passivation contact structure according to any one of claims 1 to 4, characterized in that: The monobasic strong base includes one or more of potassium hydroxide and sodium hydroxide.
6. The method for preparing a passivation contact structure according to any one of claims 1 to 4, characterized in that: The method for removing the second dielectric layer includes: chain etching.
7. A passivation contact structure, characterized in that: Prepared according to the preparation method according to any one of claims 1 to 6.
8. The passivation contact structure according to claim 7, characterized in that: The thickness of the doped polysilicon layer is 70nm-130nm.
9. A solar cell, characterized in that: Comprising the passivation contact structure as claimed in claim 7 or 8.
10. An electrical device, characterized in that: The solar cell according to claim 9 is included as a power source.