An ultraviolet-degradation-resistant n-type topcon cell, a preparation method thereof, and a photovoltaic system

Abstract

This application provides an N-type TOPCON cell with UV degradation resistance, its fabrication method, and a photovoltaic system, relating to the field of solar cells. The N-type TOPCON cell comprises, in the direction away from the N-type crystalline silicon substrate, the following components arranged sequentially: the N-type crystalline silicon substrate, a surface layer, an interface layer, and SiO₂. x Layer, AlO x Layer, SiN x The surface layer, the EPE layer, and the photovoltaic coated glass are combined; wherein the surface layer and the interface layer form a double-layer hydrogen structure. The N-type TOPCON cell provided in this application can improve carrier transport efficiency while effectively blocking the diffusion of metal impurities by the alumina layer, which also contributes to better voltage retention and power output stability.

Description

Technical Field

[0001] This application relates to the field of solar cells, and more particularly to an N-type TOPCON cell resistant to ultraviolet degradation, its preparation method, and a photovoltaic system thereof. Background Technology

[0002] One of the key advantages of the N-type TOPCON battery structure is its high-quality passivation layer on the back, typically composed of an ultra-thin aluminum oxide (Al₂O₃) layer. x ) layer and silicon nitride (SiN) x A multilayer thin film composed of ) layers. Among them, AlO₂ x The layer primarily provides excellent field-effect passivation and chemical passivation, while SiN... x The layer primarily provides excellent optical anti-reflection effects and acts as a hydrogen source. Hydrogen atoms in SiN... x The layer exists in the form of silicon-hydrogen bonds (Si-H) and diffuses to the silicon wafer interface during sintering, effectively passivating dangling bond defects on the silicon surface, thereby significantly improving carrier lifetime and battery efficiency.

[0003] Current technologies generally use SiN x / AlO x In long-term outdoor operation, the stacked passivation structure of the battery is subjected to continuous and intense sunlight exposure, especially high-energy ultraviolet (UV) irradiation. Studies have shown that UV photons possess sufficient energy to directly or indirectly cause SiN... x The Si-H bonds in the layer break. This photo-induced or UV-induced degradation causes the hydrogen atoms that originally provided passivation to dissociate and diffuse away, resulting in a significant deterioration in the passivation quality of the interface. The direct consequence is an increase in the silicon surface state density and a sharp rise in the minority carrier recombination rate, ultimately manifesting as an irreversible decline in the cell's open-circuit voltage (Voc), fill factor (FF), and overall power conversion efficiency (PCE), severely affecting the long-term stability and power output of TOPCon cells.

[0004] To improve passivation quality, a high-temperature annealing process is typically employed. The main function of this process is to promote SiN… x The release of hydrogen from the layer and its diffusion to the silicon interface repair some bulk or interface defects, improving the initial passivation effect. However, this traditional annealing method has a fundamental limitation: it mainly acts on the initial formation of the passivation layer or the activation of bulk hydrogen, but cannot effectively solve the problem of dynamic bond breakage caused by ultraviolet irradiation, a specific external stress source. High-temperature annealing can neither enhance the fracture resistance of the Si-H bond itself under ultraviolet light, nor can it continuously replenish the hydrogen atoms lost due to ultraviolet irradiation during long-term battery operation.

[0005] Therefore, existing annealing processes are basically ineffective in suppressing UV-induced hydrogen bond breakage and the resulting continuous degradation of the passivation layer, and cannot meet the requirements for long-term stable operation of TOPCon batteries outdoors. Summary of the Invention

[0006] The purpose of this application is to provide an N-type TOPCON cell with resistance to ultraviolet degradation, its preparation method, and a photovoltaic system, in order to solve the above-mentioned problems.

[0007] To achieve the above objectives, this application adopts the following technical solution:

[0008] This application provides an N-type TOPCON cell with resistance to ultraviolet degradation. The N-type TOPCON cell, moving away from the N-type crystalline silicon substrate, comprises, in sequence: the N-type crystalline silicon substrate, a surface layer, an interface layer, and SiO₂. x Layer, AlO x Layer, SiN x Layer, EPE layer, photovoltaic coated glass;

[0009] The surface layer and the interface layer are a bilayer hydrogen structure.

[0010] Optionally, the thickness of the surface layer is no greater than 1 nm.

[0011] Optionally, the thickness of the interface layer is 1-3 nm.

[0012] Optionally, the SiO x The thickness of the layer is 1-2 nm.

[0013] Optionally, the AlO x The thickness of the layer is 4.6-5 nm.

[0014] Optionally, the SiN x The thickness of the layer is 70-90nm.

[0015] Optionally, the thickness of the EPE layer is 0.5-2 mm.

[0016] Optionally, the SiN x The refractive index of the layer is 2.15-2.25.

[0017] Optionally, the concentration of hydrogen atoms in the bilayer hydrogen structure decreases in the direction away from the N-type crystalline silicon substrate.

[0018] Optionally, the hydrogen atom concentration in the surface layer is 4.5-5.5 × 10⁻⁶. 19 cm -3 .

[0019] Optionally, the hydrogen atom concentration in the interface layer is 0.5-1.5×10⁻⁶. 19cm -3 .

[0020] This application also provides a method for preparing an N-type TOPCON battery resistant to ultraviolet degradation, the method comprising:

[0021] The SiO is disposed on the surface of the N-type crystalline silicon substrate. x The reaction yields a polycrystalline silicon layer.

[0022] The AlO is disposed on the surface of the polycrystalline silicon layer. x After the layer is applied, annealing and ultraviolet (UV) treatment are performed sequentially; the AlO₂ on the silicon wafer that has undergone UV treatment is then... x The SiN layer surface is provided with the SiN x The N-type TOPCON battery with UV degradation resistance was obtained after layering and encapsulation testing.

[0023] Optionally, the annealing process is a gradient annealing process, which includes a low-temperature stage and a high-temperature stage.

[0024] Optionally, the conditions for the low-temperature stage are as follows: in an N2 atmosphere, the temperature is increased to 480-520°C at a heating rate of 4-6°C / min, and held for 9-11 minutes.

[0025] Optionally, the conditions for the high-temperature stage are as follows: in an atmosphere of H2 and O2 mixed gas with a volume ratio of 1:3-5, the temperature is increased to 600-700℃ at a heating rate of 2℃ / min and held for 15min.

[0026] Optionally, the ultraviolet treatment conditions are: ultraviolet photon energy of 4.4-5.0 eV, wavelength of 280-320 nm, and irradiation intensity of 50 mW / cm². 2 The time is 30 seconds.

[0027] This application also provides a photovoltaic system including the aforementioned UV-resistant N-type TOPCON cell.

[0028] Compared with the prior art, the beneficial effects of this application include:

[0029] In this application's technical solution, the tunneling oxide layer and the polycrystalline silicon layer combine to form a carrier tunneling channel, reducing interface recombination losses. The alumina layer, through its dense structure, restricts excessive hydrogen atom penetration while simultaneously blocking the diffusion of metallic impurities into the silicon substrate. The high refractive index design of the silicon nitride layer reflects ultraviolet light, reducing photon absorption within the passivation layer. The photovoltaic-coated glass of the outer encapsulation layer selectively filters short-wave ultraviolet light, forming spectrally complementary protection with the inner passivation layer. The high concentration of hydrogen on the surface layer provides immediate passivation capability, while the interface layer, acting as a hydrogen reservoir, dynamically releases hydrogen atoms during ultraviolet irradiation, maintaining continuous passivation of the interface dangling bonds. The thickness-matched design of the alumina and silicon nitride layers balances hydrogen diffusion control and ultraviolet reflection efficiency, and the grain boundary structure of the polycrystalline silicon layer optimizes carrier collection efficiency. Furthermore, hydrogen atom loss induced by ultraviolet irradiation is effectively suppressed; the EPE material and photovoltaic-coated glass of the outer encapsulation layer block high-energy ultraviolet light penetration, and the dynamic hydrogen replenishment mechanism of the passivation layer maintains the quality of interface passivation. The technical solution provided in this application can improve the carrier transport efficiency while effectively blocking the diffusion of metal impurities by the alumina layer, which is also conducive to exhibiting better voltage retention rate and power output stability. Attached Figure Description

[0030] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation on the scope of this application.

[0031] Figure 1 A schematic diagram of the structure of the N-type TOPCON battery with UV degradation resistance provided in the embodiment;

[0032] Figure 2 This is a photograph of the N-type TOPCON battery with UV degradation resistance prepared in Example 1.

[0033] Figure 3 XPS spectra of Si-O bonds in the interface layer of the UV-resistant N-type TOPCON cell provided in Example 1;

[0034] Figure 4 XPS spectra of Si-O bonds in the interface layer of the N-type TOPCON cell with UV degradation resistance provided for Comparative Example 1.

[0035] The main labels are as follows:

[0036] 100 - N-type crystalline silicon substrate; 101 - Surface layer; 102 - Interface layer; 103 - SiO x Layer; 104-AlO x Layer; 105-SiN x Layer; 106-EPE material layer; 107-photovoltaic coated glass. Detailed Implementation

[0037] As used in this article:

[0038] "Prepared from" is synonymous with "comprising". The terms "comprising", "including", "having", "containing", or any other variations thereof as used herein are intended to cover non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that includes the listed elements is not necessarily limited to those elements, but may include other elements not expressly listed or elements inherent to such composition, step, method, article, or apparatus.

[0039] The conjunction "composed of..." excludes any unspecified elements, steps, or components. If used in a claim, this phrase makes the claim closed, excluding materials other than those described, except for associated conventional impurities. When the phrase "composed of..." appears in a clause of the body of a claim rather than immediately following it, it limits only the elements described in that clause; other elements are not excluded from the claim as a whole.

[0040] When a quantity, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pair of any upper or preferred value with any lower or preferred value, regardless of whether the range is disclosed individually. For example, when the range “1–5” is disclosed, the described range should be interpreted as including ranges “1–4”, “1–3”, “1–2”, “1–2 and 4–5”, “1–3 and 5”, etc. When numerical ranges are described herein, unless otherwise stated, the range is intended to include its endpoints and all integers and fractions within that range.

[0041] In these embodiments, unless otherwise specified, the portions and percentages are all by weight.

[0042] "Parts by mass" refers to the basic unit of measurement that expresses the mass ratio of multiple components. One part can represent any unit mass, such as 1g or 2.689g. If we say that component A has "a" parts by mass and component B has "b" parts by mass, it means the ratio of the mass of component A to the mass of component B is a:b. Alternatively, it can mean that the mass of component A is aK and the mass of component B is bK (K is any number representing a multiplier). It is important to understand that, unlike the number of parts by mass, the sum of the mass parts of all components is not limited to 100 parts.

[0043] "And / or" is used to indicate that one or both of the described situations may occur, for example, A and / or B includes (A and B) and (A or B).

[0044] To better explain the technical solution of this application, the technical solution will be described in its entirety before proceeding with specific implementation methods.

[0045] In a first aspect, this application provides an N-type TOPCON cell with resistance to ultraviolet degradation, wherein the N-type TOPCON cell, in the direction away from the N-type crystalline silicon substrate, comprises: the N-type crystalline silicon substrate, a surface layer, an interface layer, and SiO2. x Layer, AlO x Layer, SiN x Layer, EPE layer, photovoltaic coated glass;

[0046] The surface layer and the interface layer are a bilayer hydrogen structure.

[0047] Compared to existing technologies, traditional passivation structures use a single silicon nitride layer as the hydrogen source and lack a dynamic replenishment mechanism. This solution achieves a gradient distribution of hydrogen concentration through a bilayer hydrogen structure, continuously repairing broken silicon-hydrogen bonds during ultraviolet irradiation. Existing encapsulation layers only focus on mechanical protection and light transmission; this solution, through the synergistic effect of coated glass and polyvinyl acetal resin, forms a segmented cutoff barrier for the ultraviolet spectrum. Compared to traditional multilayer passivation structures, the newly added flint-penetrating oxide layer and polycrystalline silicon layer optimize carrier transport paths and reduce interfacial recombination rates.

[0048] In one optional embodiment, the thickness of the surface layer is no greater than 1 nm; the thickness of the interface layer is 1-3 nm; the SiO x The thickness of the layer is 1-2 nm; the AlO x The SiN layer has a thickness of 4.6-5 nm. x The thickness of the layer is 70-90nm; the thickness of the EPE layer is 0.5-2mm.

[0049] Optionally, the thickness of the surface layer can be 0.1nm, 0.2nm, 0.3nm, 0.4nm, 0.5nm, 0.6nm, 0.7nm, 0.8nm, 0.9nm, 1nm, or any value not greater than 1nm.

[0050] Optionally, the thickness of the interface layer can be 1nm, 1.1nm, 1.2nm, 1.3nm, 1.4nm, 1.5nm, 1.6nm, 1.7nm, 1.8nm, 1.9nm, 2nm, 2.1nm, 2.2nm, 2.3nm, 2.4nm, 2.5nm, 2.6nm, 2.7nm, 2.8nm, 2.9nm, 3nm, or any value between 1 and 3nm.

[0051] Optional, AlO xThe thickness of the layer can be 4.6nm, 4.65nm, 4.7nm, 4.75nm, 4.8nm, 4.85nm, 4.9nm, 4.95nm, 5nm, or any value between 4.6nm and 5nm.

[0052] Optional, SiO x The thickness of the layer can be 1nm, 1.1nm, 1.2nm, 1.3nm, 1.4nm, 1.5nm, 1.6nm, 1.7nm, 1.8nm, 1.9nm, 2nm, or any thickness between 1nm and 2nm.

[0053] Optional, AlO x The thickness of the layer can be 4.6nm, 4.7nm, 4.8nm, 4.9nm, 5nm, or any value between 4.6nm and 5nm.

[0054] Optional, SiN x The thickness of the layer can be 70nm, 71nm, 72nm, 73nm, 74nm, 75nm, 76nm, 77nm, 78nm, 79nm, 80nm, 81nm, 82nm, 83nm, 84nm, 85nm, 86nm, 87nm, 88nm, 89nm, 90nm, or any value between 70nm and 90nm.

[0055] Optionally, the thickness of the EPE layer can be 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2mm, or any value between 0.5mm and 2mm.

[0056] At this thickness, the dynamic processes of hydrogen atom diffusion and oxygen atom migration can be effectively balanced, when AlO x When the layer is within this thickness range, hydrogen atoms can diffuse moderately to the silicon interface to complete the passivation effect, while oxygen atoms can still effectively migrate to the interface region to form a stable Si-O bond structure. On the one hand, it can match the diffusion depth of hydrogen atoms, avoiding excessive hydrogen atom penetration that would lead to a porous interface, while ensuring the integrity of the passivation layer; on the other hand, AlO x If the layer thickness is too thick, it will hinder the diffusion of oxygen atoms, leading to a decrease in the Si-O bond coverage. x When the thickness exceeds 5.2 nm, the Si-O bond ratio drops from 78% to 65%; if it is too thin (less than 4.5 nm), it cannot effectively block the diffusion of metal impurities.

[0057] In an optional implementation, the SiN x The refractive index of the layer is 2.15-2.25.

[0058] Optional, SiN x The refractive index of the layer can be 2.15, 2.16, 2.17, 2.18, 2.19, 2.2, 2.21, 2.22, 2.23, 2.24, 2.25, or any value between 2.15 and 2.25.

[0059] For SiN x The refractive index of the layer is selected, and its range is set to balance the enhancement of ultraviolet reflection and the efficiency of carrier transport. A higher refractive index can improve the ultraviolet light reflectivity, but an excessively high refractive index will increase the resistance to carrier transport; if the refractive index is too low, the ultraviolet cutoff rate will be less than 90%.

[0060] By controlling AlO x Layer thickness and SiN x The refractive index of the passivation layer effectively suppresses the loss of hydrogen atoms caused by ultraviolet irradiation, maintains the chemical stability of the passivation layer interface, and optimizes the optical reflection characteristics and carrier transport efficiency of the passivation layer, thus solving the technical problem of performance degradation of traditional passivation layers under long-term ultraviolet exposure.

[0061] In an alternative embodiment, the concentration of hydrogen atoms in the bilayer hydrogen structure decreases in the direction away from the N-type crystalline silicon substrate.

[0062] This application further proposes that the hydrogen atom concentration in the surface layer is 4.5-5.5 × 10⁻⁶. 19 cm -3 .

[0063] This application further proposes that the hydrogen atom concentration in the interface layer is 0.5-1.5 × 10⁻⁶. 19 cm -3 .

[0064] This process is in Si / SiO xThe interface region forms two layers with different hydrogen concentrations and functions. The high concentration of hydrogen atoms in the surface layer forms a "protective wall," primarily forming Si-H bonds, thus creating a dense chemical bond network. This effectively blocks oxygen atoms from diffusing into the silicon from the external environment, preventing oxygen impurities from diffusing into the silicon lattice and forming defects such as oxygen precipitates, which become carrier recombination centers and significantly reduce device efficiency. The low concentration of hydrogen atoms in the interface layer forms a "harmonizing layer." In this layer, hydrogen atoms mainly combine with oxygen at the interface: on the one hand, hydrogen atoms preferentially saturate the dangling bonds at the interface, i.e., (Si-) or (O-), which reduces the interface state density and thus suppresses carrier recombination, improving passivation. On the other hand, Si-O bonds are more stable than Si-Si bonds, resulting in a smoother band shift, which facilitates carrier tunneling, reducing interface resistance and improving transport efficiency.

[0065] Secondly, this application also provides a method for preparing an N-type TOPCON battery resistant to ultraviolet degradation, the method comprising:

[0066] The SiO is disposed on the surface of the N-type crystalline silicon substrate. x The reaction yields a polycrystalline silicon layer.

[0067] The AlO is disposed on the surface of the polycrystalline silicon layer. x After the layer is applied, annealing and ultraviolet (UV) treatment are performed sequentially; the AlO₂ on the silicon wafer that has undergone UV treatment is then... x The SiN layer surface is provided with the SiN x The N-type TOPCON battery with UV degradation resistance was obtained after layering and encapsulation testing.

[0068] Specifically, in AlO x After the passivation layer deposition is completed, gradient annealing is used to activate interstitial hydrogen atoms in the passivation layer, allowing them to diffuse towards the silicon interface to repair initial defects. Subsequently, ultraviolet irradiation is applied, using photon energy to induce a rearrangement of hydrogen atoms within the passivation layer, forming a stable bonded structure with UV resistance. Finally, SiN is deposited. x The layered composite passivation system retains the optical antireflective properties of traditional multilayer passivation structures while enhancing its resistance to degradation through a dynamic hydrogen regulation mechanism formed by ultraviolet (UV) treatment. The sequential arrangement of annealing and UV treatment avoids the damage to the UV-induced structure caused by high-temperature treatment, enabling the passivation layer to continuously resist bond breakage induced by UV irradiation during operation.

[0069] Existing technologies rely solely on high-temperature annealing to promote hydrogen diffusion, failing to address the dynamic hydrogen loss caused by ultraviolet (UV) irradiation. This application introduces a UV treatment stage to construct a defect-resistant structure within the passivation layer, while simultaneously optimizing the synergistic effect of annealing and UV treatment. In traditional processes, annealing and passivation layer deposition are a single, continuous process; however, this method places annealing as an independent step prior to UV treatment, forming a staged processing flow. This adjustment in process sequence effectively blocks the chain reaction of Si-H bond breaking induced by UV irradiation.

[0070] In one optional implementation, the annealing process is a gradient annealing process, which includes a low-temperature stage and a high-temperature stage.

[0071] In an optional implementation, the conditions for the low-temperature stage are as follows: in an N2 atmosphere, the temperature is increased to 480-520°C at a heating rate of 4-6°C / min, and held for 9-11 minutes.

[0072] In the selectable low-temperature stage, the heating rate can be 4℃ / min, 5℃ / min, 6℃ / min, or any value between 4℃ / min and 6℃ / min; the key temperature of the low-temperature stage can be 480℃, 485℃, 490℃, 495℃, 500℃, 505℃, 510℃, 515℃, 520℃, or any value between 480℃ and 520℃; the holding time can be 9min, 10min, 11min, or any value between 9min and 11min.

[0073] In an optional embodiment, the conditions for the high-temperature stage are as follows: in an atmosphere of H2 and O2 mixed gas with a volume ratio of 1:3-5, the temperature is increased to 600-700℃ at a heating rate of 2℃ / min and held for 15min.

[0074] Optionally, the volume ratio of the H2 and O2 mixed gas atmosphere in the high-temperature stage can be 1:3, 1:4, 1:5, or any value between 1:3 and 5; the endpoint temperature of the high-temperature stage can be 600℃, 610℃, 620℃, 630℃, 640℃, 650℃, 660℃, 670℃, 680℃, 690℃, 700℃, or any value between 600℃ and 700℃.

[0075] Specifically, in the low-temperature stage, a nitrogen atmosphere is used to prevent premature hydrogen atom escape. At 500 degrees Celsius, interstitial hydrogen atoms in the passivation layer are activated, allowing them to diffuse towards the silicon interface to repair initial defects. Subsequently, in the high-temperature stage, a hydrogen-oxygen mixture is used. By precisely controlling the heating rate and gas ratio, oxygen atoms preferentially combine with interfacial dangling bonds, forming a Si-O bond structure with high coverage and strong bond energy. This staged processing mechanism allows the passivation layer to effectively replenish hydrogen atoms while constructing a chemical bond network resistant to ultraviolet photon impacts. The slow heating in the low-temperature stage, under nitrogen protection, provides sufficient migration kinetic energy for interstitial hydrogen atoms in the passivation layer, enabling them to diffuse orderly to the silicon interface region and preventing excessive hydrogen atom escape due to high temperatures. In the high-temperature stage, in the hydrogen-oxygen mixture environment, oxygen atoms preferentially combine with silicon interfacial dangling bonds to form a high-bond-energy Si-O network structure, which exhibits higher resistance to ultraviolet photon impacts. The synergistic effect of two-stage process parameters—the heating rate and holding time in the low-temperature stage match the hydrogen atom activation threshold, and the mixed gas ratio and temperature parameters in the high-temperature stage match the oxygen atom diffusion kinetics requirements—creates a dual passivation interface that combines dynamic hydrogen replenishment and stable bonding. This effectively enhances the passivation layer's fracture resistance under ultraviolet irradiation. The stable Si-O bond network formed through gradient annealing can resist high-energy photon impacts, while the interstitial hydrogen atoms activated in the low-temperature stage continuously replenish the hydrogen lost due to ultraviolet irradiation during battery operation, thereby significantly reducing interface defect density and maintaining the long-term stability of the passivation layer.

[0076] In an optional embodiment, the ultraviolet treatment conditions are: ultraviolet photon energy of 4.4-5.0 eV, wavelength of 280-320 nm, and irradiation intensity of 50 mW / cm². 2 The time is 30 seconds.

[0077] Optionally, the ultraviolet photon energy can be 4.4 eV, 4.5 eV, 4.6 eV, 4.7 eV, 4.8 eV, 4.9 eV, 5 eV, or any value between 4.4 and 5 eV; the ultraviolet wavelength can be 280 nm, 285 nm, 290 nm, 295 nm, 300 nm, 305 nm, 310 nm, 315 nm, 320 nm, or any value between 280 and 300 nm.

[0078] Thirdly, this application also provides a photovoltaic system including the aforementioned UV-resistant N-type TOPCON cell.

[0079] The implementation schemes of this application will be described in detail below with reference to specific embodiments. However, those skilled in the art will understand that the following embodiments are only for illustrating this application and should not be regarded as limiting the scope of this application. Unless otherwise specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments used without specified manufacturers are all conventional products that can be purchased commercially.

[0080] Example 1

[0081] This embodiment provides an N-type TOPCON battery that resists ultraviolet degradation:

[0082] The N-type TOPCON cells, moving away from the N-type crystalline silicon substrate 100, are as follows:

[0083] 100 N-type crystalline silicon substrate;

[0084] Surface layer 101: 0.8 nm thick, TOF-SIMS measured hydrogen atom concentration of 5 × 10⁻⁶. 19 cm -3 ;

[0085] Interface layer 102: 2 nm thick, TOF-SIMS measured hydrogen atom concentration of 1 × 10⁻⁶. 19 cm -3 ;

[0086] SiO x Layer 103: 1.5 nm thick;

[0087] AlO x Layer 104: 4.8 nm thick;

[0088] SiN x Layer 105: 80 nm thick, refractive index 2.20;

[0089] EPE material layer 106: 1.5mm;

[0090] Photovoltaic coated glass 107.

[0091] XPS deep analysis revealed that the Si-O bond ratio in the interface layer was 78%, such as... Figure 3 As shown.

[0092] This embodiment also provides a method for preparing an N-type TOPCON battery resistant to ultraviolet degradation, the specific steps of which are as follows:

[0093] After cleaning the N-type crystalline silicon substrate, a tunneling oxide layer, namely SiO, is deposited on its surface using conventional methods. x After doping, a polycrystalline silicon layer is obtained; and AlO is deposited on the surface of the polycrystalline silicon layer using conventional parameters via ALD deposition. x layer.

[0094] Gradient annealing is performed using a multi-chamber continuous annealing furnace with independent gas supply systems for N2 / H2 / O2:

[0095] Low temperature stage: In an N2 atmosphere, the temperature is increased to 500℃ at a heating rate of 5℃ / min and held for 10min to activate hydrogen atoms in the passivation interlayer.

[0096] High temperature stage: In an atmosphere of H2 and O2 mixed gas with a volume ratio of 1:5, the temperature is increased to 650℃ at a heating rate of 2℃ / min and held for 15min.

[0097] Ultraviolet treatment was performed using SAMCO UV-300HC:

[0098] The wavelength was set at 300 nm, and the irradiation intensity was 50 mW / cm². 2 The irradiation time is 30 seconds, which triggers the dynamic recombination of hydrogen atoms to form a structure resistant to ultraviolet defects.

[0099] SiN was deposited on an annealed silicon wafer using PECVD with 200 sccm of silane, 150 sccm of ammonia, and 50 sccm of nitrous oxide, for 25 min at a temperature of 350°C. x Layer. An N-type TOPCON cell resistant to UV degradation was fabricated by encapsulating it with EPE material and photovoltaic coated glass.

[0100] Example 2

[0101] This embodiment provides an N-type TOPCON battery that resists ultraviolet degradation:

[0102] The N-type TOPCON cells, moving away from the N-type crystalline silicon substrate 100, are as follows:

[0103] 100 N-type crystalline silicon substrate;

[0104] Surface layer 101: 0.5 nm thick, hydrogen atom concentration of 5 × 10⁻⁶ 19 cm -3 ;

[0105] Interface layer 102: 1 nm thick, with a hydrogen atom concentration of 1 × 10⁻⁶. 19 cm -3 ;

[0106] SiO x Layer 103: 1 nm thick;

[0107] AlO x Layer 104: 4.6 nm thick;

[0108] SiN xLayer 105: 70 nm thick, refractive index 2.15;

[0109] EPE material layer 106: 0.5mm;

[0110] Photovoltaic coated glass 107.

[0111] This embodiment also provides a method for preparing an N-type TOPCON battery resistant to ultraviolet degradation, the specific steps of which are as follows:

[0112] After cleaning the N-type crystalline silicon substrate, a tunneling oxide layer, namely SiO, is deposited on its surface using conventional methods. x After doping, a polycrystalline silicon layer is obtained; and AlO is deposited on the surface of the polycrystalline silicon layer using conventional parameters via ALD deposition. x layer.

[0113] Perform gradient annealing:

[0114] Low temperature stage: In an N2 atmosphere, the temperature is increased to 480℃ at a heating rate of 5℃ / min and held for 10min to activate hydrogen atoms in the passivation interlayer.

[0115] In the high-temperature stage, the temperature was increased to 600℃ in an atmosphere of H2 and O2 mixed gas with a volume ratio of 1:5, at a heating rate of 2℃ / min, and held for 15min.

[0116] Perform ultraviolet treatment:

[0117] The wavelength was set at 280 nm, and the irradiance was 50 mW / cm². 2 The irradiation time is 30 seconds, which triggers the dynamic recombination of hydrogen atoms to form a structure resistant to ultraviolet defects.

[0118] SiN was deposited on annealed silicon wafers using PECVD with conventional parameters. x Layer. An N-type TOPCON cell resistant to UV degradation was fabricated by encapsulating it with EPE material and photovoltaic coated glass.

[0119] Example 3

[0120] This embodiment provides an N-type TOPCON battery that resists ultraviolet degradation:

[0121] The N-type TOPCON cells, moving away from the N-type crystalline silicon substrate 100, are as follows:

[0122] 100 N-type crystalline silicon substrate;

[0123] Surface layer 101: 1 nm thick, with a hydrogen atom concentration of 5 × 10⁻⁶. 19 cm -3 ;

[0124] Interface layer 102: 3 nm thick, hydrogen atom concentration 1 × 10⁻⁶ 19 cm -3 ;

[0125] SiO x Layer 103: 2nm thick;

[0126] AlO x Layer 104: 5nm thick;

[0127] SiN x Layer 105: 90 nm thick, refractive index 2.25;

[0128] EPE material layer 106: 2mm;

[0129] Photovoltaic coated glass 107.

[0130] This embodiment also provides a method for preparing an N-type TOPCON battery resistant to ultraviolet degradation, the specific steps of which are as follows:

[0131] After cleaning the N-type crystalline silicon substrate, a tunneling oxide layer, namely SiO, is deposited on its surface using conventional methods. x After doping, a polycrystalline silicon layer is obtained; and AlO is deposited on the surface of the polycrystalline silicon layer using conventional parameters via ALD deposition. x layer.

[0132] Perform gradient annealing:

[0133] Low temperature stage: In an N2 atmosphere, the temperature is increased to 520℃ at a heating rate of 5℃ / min and held for 10min to activate hydrogen atoms in the passivation interlayer.

[0134] In the high-temperature stage, the temperature was increased to 700℃ in an atmosphere of H2 and O2 mixed gas with a volume ratio of 1:5 at a heating rate of 2℃ / min, and held for 15min.

[0135] Perform ultraviolet treatment:

[0136] The wavelength was set at 320 nm, and the irradiance was 50 mW / cm². 2 The irradiation time is 30 seconds, which triggers the dynamic recombination of hydrogen atoms to form a structure resistant to ultraviolet defects.

[0137] SiN was deposited on annealed silicon wafers using PECVD with conventional parameters. x Layer. An N-type TOPCON cell resistant to UV degradation was fabricated by encapsulating it with EPE material and photovoltaic coated glass.

[0138] Comparative Example 1

[0139] This comparative example provides a conventional N-type TOPCON battery:

[0140] The N-type TOPCON cells, moving away from the N-type crystalline silicon substrate, are as follows:

[0141] N-type crystalline silicon substrate;

[0142] SiO x Layer: 2 nm thick, TOF-SIMS measured hydrogen atom concentration of 5 × 10⁻⁶. 18 cm -3 ;

[0143] AlO x Layer: 5nm thick;

[0144] SiN x Layer: 75nm thick, refractive index 2.17;

[0145] EPE material layer: 2mm;

[0146] Photovoltaic coated glass.

[0147] XPS deep analysis revealed that the Si-O bond ratio in the interface layer was 52%.

[0148] This comparative example also provides a method for preparing the N-type TOPCON battery using conventional processes, the specific steps of which are as follows:

[0149] After cleaning the N-type crystalline silicon substrate, a tunneling oxide layer, namely SiO, is deposited on its surface using conventional methods. x After doping, a polycrystalline silicon layer is obtained; and AlO is deposited on the surface of the polycrystalline silicon layer using conventional parameters via ALD deposition. x layer.

[0150] Perform annealing:

[0151] Annealing is performed by directly heating the temperature to 750℃.

[0152] SiN was deposited on annealed silicon wafers using PECVD with conventional parameters. x Layer. N-type TOPCON cells are fabricated by encapsulating them with EPE material and photovoltaic coated glass.

[0153] Comparative Example 2

[0154] This comparative example provides an N-type TOPCON battery with resistance to UV degradation:

[0155] The N-type TOPCON cells, moving away from the N-type crystalline silicon substrate, are as follows:

[0156] N-type crystalline silicon substrate;

[0157] Surface layer: 0.5 nm thick, hydrogen atom concentration of 5 × 10⁻⁶ 19 cm-3 ;

[0158] Interface layer: 2 nm thick, hydrogen atom concentration 1 × 10⁻⁶ 19 cm -3 ;

[0159] SiO x Layer: 1.5 nm thick;

[0160] AlO x Layer: 4.8 nm thick;

[0161] SiN x Layer: 70nm thick, refractive index 2.20.

[0162] This embodiment also provides a method for preparing an N-type TOPCON battery resistant to ultraviolet degradation, the specific steps of which are as follows:

[0163] After cleaning the N-type crystalline silicon substrate, a tunneling oxide layer, namely SiO, is deposited on its surface using conventional methods. x After doping, a polycrystalline silicon layer is obtained; and AlO is deposited on the surface of the polycrystalline silicon layer using conventional parameters via ALD deposition. x layer.

[0164] Perform gradient annealing:

[0165] Low temperature stage: In an N2 atmosphere, the temperature is increased to 500℃ at a heating rate of 5℃ / min and held for 10min to activate hydrogen atoms in the passivation interlayer.

[0166] In the high-temperature stage, the temperature was increased to 650℃ in an atmosphere of H2 and O2 mixed gas with a volume ratio of 1:5, at a heating rate of 2℃ / min, and held for 15min.

[0167] Perform ultraviolet treatment:

[0168] The wavelength was set at 280 nm, and the irradiance was 50 mW / cm². 2 The irradiation time is 30 seconds, which triggers the dynamic recombination of hydrogen atoms to form a structure resistant to ultraviolet defects.

[0169] The PECVD method is used to deposit SiN on annealed silicon wafers. x A layer was used to fabricate an N-type TOPCON cell resistant to ultraviolet degradation.

[0170] Comparative Example 3

[0171] This comparative example provides an N-type TOPCON battery with resistance to UV degradation:

[0172] The N-type TOPCON cells, moving away from the N-type crystalline silicon substrate, are as follows:

[0173] N-type crystalline silicon substrate;

[0174] Surface layer: 0.8 nm thick, hydrogen atom concentration of 5 × 10⁻⁶ 19 cm -3 ;

[0175] Interface layer: 1.6 nm thick, hydrogen atom concentration 1 × 10⁻⁶ 19 cm -3 ;

[0176] SiO x Layer: 1.5 nm thick;

[0177] AlO x Layer: 5.5 nm thick;

[0178] SiN x Layer: 90nm thick, refractive index 2.20;

[0179] EPE material layer: 2mm;

[0180] Photovoltaic coated glass.

[0181] The comparative example also provides a method for preparing an N-type TOPCON battery resistant to UV degradation, the specific steps of which are as follows:

[0182] After cleaning the N-type crystalline silicon substrate, a tunneling oxide layer, namely SiO, is deposited on its surface using conventional methods. x After doping, a polycrystalline silicon layer is obtained; and AlO is deposited on the surface of the polycrystalline silicon layer using conventional parameters via ALD deposition. x layer.

[0183] Perform gradient annealing:

[0184] Low temperature stage: In an N2 atmosphere, the temperature is increased to 500℃ at a heating rate of 5℃ / min and held for 10min to activate hydrogen atoms in the passivation interlayer.

[0185] In the high-temperature stage, the temperature was increased to 650℃ in an atmosphere of H2 and O2 mixed gas with a volume ratio of 1:5, at a heating rate of 2℃ / min, and held for 15min.

[0186] Perform ultraviolet treatment:

[0187] The wavelength was set at 290 nm, and the irradiance was 50 mW / cm². 2 The irradiation time is 30 seconds, which triggers the dynamic recombination of hydrogen atoms to form a structure resistant to ultraviolet defects.

[0188] SiN was deposited on annealed silicon wafers using PECVD with conventional parameters. xLayer. An N-type TOPCON cell resistant to UV degradation was fabricated by encapsulating it with EPE material and photovoltaic coated glass.

[0189] Comparative Example 4

[0190] This comparative example provides an N-type TOPCON battery with resistance to UV degradation:

[0191] The N-type TOPCON cells, moving away from the N-type crystalline silicon substrate, are as follows:

[0192] N-type crystalline silicon substrate;

[0193] Surface layer: 0.8 nm thick, hydrogen atom concentration of 5 × 10⁻⁶ 19 cm -3 ;

[0194] Interface layer: 1.5 nm thick, hydrogen atom concentration 1 × 10⁻⁶ 19 cm -3 ;

[0195] SiO x Layer: 1.5 nm thick;

[0196] AlO x Layer: 4.8 nm thick;

[0197] SiN x Layer: 85nm thick, refractive index 2.30;

[0198] EPE material layer: 15mm;

[0199] Photovoltaic coated glass.

[0200] The comparative example also provides a method for preparing an N-type TOPCON battery resistant to UV degradation, the specific steps of which are as follows:

[0201] After cleaning the N-type crystalline silicon substrate, a tunneling oxide layer, namely SiO, is deposited on its surface using conventional methods. x After doping, a polycrystalline silicon layer is obtained; and AlO is deposited on the surface of the polycrystalline silicon layer using conventional parameters via ALD deposition. x layer.

[0202] Perform gradient annealing:

[0203] Low temperature stage: In an N2 atmosphere, the temperature is increased to 500℃ at a heating rate of 5℃ / min and held for 10min to activate hydrogen atoms in the passivation interlayer.

[0204] In the high-temperature stage, the temperature was increased to 650℃ in an atmosphere of H2 and O2 mixed gas with a volume ratio of 1:5, at a heating rate of 2℃ / min, and held for 15min.

[0205] Perform ultraviolet treatment:

[0206] The wavelength was set at 300 nm, and the irradiation intensity was 50 mW / cm². 2 The irradiation time is 30 seconds, which triggers the dynamic recombination of hydrogen atoms to form a structure resistant to ultraviolet defects.

[0207] SiN was deposited on annealed silicon wafers using PECVD with conventional parameters. x Layer. An N-type TOPCON cell resistant to UV degradation was fabricated by encapsulating it with EPE material and photovoltaic coated glass.

[0208] The performance information of the N-type TOPCON batteries prepared in the examples and comparative examples is shown in Table 1:

[0209] Table 1. Information on TOPCON batteries obtained in the examples and comparative examples.

[0210]

[0211]

[0212] As shown in Table 1, Examples 1 / 2 / 3 significantly improved the UV cutoff rate through the synergistic effect between the film layers. Different concentrations of surface and interface layers enhanced the passivation effect and increased minority carrier lifetime, thereby improving the battery conversion efficiency. The effects of Comparative Examples 1 / 2 / 3 / 4 after parameter adjustments all deteriorated and failed to achieve the desired results of this application.

[0213] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

[0214] Furthermore, those skilled in the art will understand that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of this application and form different embodiments. For example, in the foregoing claims, any of the claimed embodiments can be used in any combination. The information disclosed in this background section is intended only to enhance the understanding of the general background of this application and should not be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

Claims

1. An N-type TOPCON battery resistant to UV degradation, characterized in that, The N-type TOPCON cell, in the direction away from the N-type crystalline silicon substrate, comprises, in sequence: the N-type crystalline silicon substrate, a surface layer, an interface layer, and SiO₂. x Layer, AlO x Layer, SiN x Layer, EPE layer, photovoltaic coated glass; The surface layer and the interface layer are a bilayer hydrogen structure.

2. The N-type TOPCON battery with UV degradation resistance according to claim 1, characterized in that, At least one of the following conditions must be met: a. The thickness of the surface layer is no greater than 1 nm; b. The thickness of the interface layer is 1-3 nm; c. The SiO x The thickness of the layer is 1-2 nm; d. The AlO x The layer thickness is 4.6-5 nm; e. The SiN x The thickness of the layer is 70-90 nm; e. The thickness of the EPE layer is 0.5-2 mm.

3. The N-type TOPCON battery with UV degradation resistance according to claim 1, characterized in that, The SiN x The refractive index of the layer is 2.15-2.

25.

4. The N-type TOPCON battery with UV degradation resistance according to claim 1, characterized in that, The concentration of hydrogen atoms in the bilayer hydrogen structure decreases in the direction away from the N-type crystalline silicon substrate.

5. The N-type TOPCON battery with UV degradation resistance according to claim 4, characterized in that, At least one of the following conditions must be met: f. The hydrogen atom concentration in the surface layer is 4.5-5.5 × 10⁻⁶. 19 cm -3 ; g. The hydrogen atom concentration in the interface layer is 0.5-1.5 × 10⁻⁶. 19 cm -3 .

6. A method for preparing an N-type TOPCON battery with UV degradation resistance according to any one of claims 1-5, characterized in that, include: The SiO is disposed on the surface of the N-type crystalline silicon substrate. x After the reaction, a polycrystalline silicon layer is obtained. The AlO is disposed on the surface of the polycrystalline silicon layer. x After the layers are applied, annealing and UV treatment are performed sequentially. The AlO₂ on the silicon wafer that has undergone the ultraviolet treatment x The SiN layer surface is provided with the SiN x The N-type TOPCON battery with UV degradation resistance was obtained after layering and encapsulation testing.

7. The preparation method according to claim 6, characterized in that, The annealing process is a gradient annealing process, which includes a low-temperature stage and a high-temperature stage.

8. The preparation method according to claim 7, characterized in that, At least one of the following conditions must be met: A. The conditions for the low-temperature stage are: in an N2 atmosphere, the temperature is increased to 480-520℃ at a heating rate of 4-6℃ / min, and held for 9-11 minutes; B. The conditions for the high-temperature stage are as follows: in an atmosphere of H2 and O2 mixed gas with a volume ratio of 1:3-5, the temperature is increased to 600-700℃ at a heating rate of 2℃ / min and held for 15min.

9. The preparation method according to any one of claims 6-8, characterized in that, The ultraviolet treatment conditions are as follows: ultraviolet photon energy of 4.4-5.0 eV, wavelength of 280-320 nm, and irradiation intensity of 50 mW / cm². 2 The time is 30 seconds.

10. A photovoltaic system, characterized in that, Including the N-type TOPCON battery with UV degradation resistance as described in any one of claims 1-5.

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