Solar cell, preparation method thereof and photovoltaic module
By optimizing the hydrogen atom concentration ratio between the doped layer and the substrate in the solar cell, and by adding an aluminum oxide layer and an antireflection layer, the problems of doped layer defects and ultraviolet degradation were solved, thereby improving photoelectric performance and lifetime.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-10
- Publication Date
- 2026-03-13
AI Technical Summary
Defects in the doped layers of solar cells and ultraviolet degradation problems affect their photoelectric performance.
By optimizing the hydrogen atom concentration ratio in the first doped layer and the substrate (A2:A1 = 1.1~2.0:1.0), and by setting the first alumina layer and the first anti-reflection layer in the doped layer and the substrate, the hydrogen atom concentration distribution is controlled, the interface passivation effect is enhanced, and carrier recombination and hydrogen atom diffusion are suppressed.
This improves the solar cells' resistance to ultraviolet degradation, enhancing their photoelectric performance and lifespan.
Smart Images
Figure CN121665757A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of solar cells, and in particular to solar cells and their preparation methods, and photovoltaic modules. Background Technology
[0002] In solar cells, defects exist on the surface of the doped layer, and solar cells also suffer from ultraviolet degradation, which affects the photoelectric performance of solar cells. Summary of the Invention
[0003] This application discloses a solar cell and its preparation method, as well as a photovoltaic module, to alleviate the defects in the doped layer and the problem of ultraviolet degradation of the solar cell.
[0004] To achieve the above objectives, in a first aspect, this application discloses a solar cell, said solar cell comprising: The substrate has a first surface and a second surface disposed opposite to each other; A first doped layer, a first alumina layer, and a first antireflection layer are sequentially disposed on the first surface of the substrate; Along the direction from the first doped layer toward the substrate, the hydrogen atom concentration in the first doped layer and the substrate shows a decreasing trend; the total hydrogen atom concentration in the first doped layer and the substrate is A1, the hydrogen atom concentration in the first antireflection layer is A2, and the ratio of A2 to A1 is (1.1~2.0):1.0.
[0005] Furthermore, A1 is 1.2 × 10 23 at / cm 3 ~1.8×10 23 at / cm 3 The value of A2 is 1.9 × 10⁻⁶. 23 at / cm 3 ~2.6×10 23 at / cm 3 .
[0006] Furthermore, the solar cell also includes a second aluminum oxide layer disposed between the first aluminum oxide layer and the first antireflection layer.
[0007] Secondly, this application provides a method for fabricating a solar cell, wherein the solar cell is the solar cell described in the first aspect, and the fabrication method includes the following steps: A first alumina layer precursor is prepared on a substrate having a first doped layer; wherein the substrate has a first surface and a second surface disposed opposite to each other, the first doped layer is disposed on the first surface, and the first alumina layer precursor is prepared on the side of the first doped layer opposite to the substrate. The first alumina layer precursor is irradiated with light to obtain the first alumina layer; wherein the process conditions for light irradiation include: light wavelength of 180 nm to 280 nm, light intensity of 80 W / cm² to 220 W / cm², and light irradiation time of 0.1 s to 80 s; A first antireflection layer is prepared on the first alumina layer.
[0008] Further, the total hydrogen atom concentration in the first doped layer and the substrate is A1, the hydrogen atom concentration in the first antireflection layer is A2, and the ratio of A2 to A1 is (1.1~2.0):1.0; and / or, The value of A1 is 1.2 × 10⁻⁶. 23 at / cm 3 ~1.8×10 23 at / cm 3 The value of A2 is 1.9 × 10⁻⁶. 23 at / cm 3 ~2.6×10 23 at / cm 3 .
[0009] Furthermore, the step of preparing the first alumina layer precursor on the substrate having the first doped layer includes: introducing a first aluminum source and water vapor into the first doped layer at 200℃~350℃, and obtaining the first alumina layer precursor by atomic layer deposition, wherein the pulse time is 1 s~15 s, the purge time is 5 s~25 s, and the number of cycles is 20~45.
[0010] Furthermore, the first aluminum source includes trimethylaluminum, the flow rate of the first aluminum source is 10 sccm to 30 sccm, and the flow rate of the water vapor is 15 sccm to 30 sccm.
[0011] Further, the first antireflection layer includes a silicon nitride layer, a silicon oxynitride layer, and a silicon oxide layer, and the step of preparing the first antireflection layer on the first aluminum oxide layer includes: Preparation of the silicon nitride layer: NH3 and silane are introduced into the first alumina layer at 400℃~600℃, and the silicon nitride layer is obtained by plasma-enhanced chemical vapor deposition for 50 s~200 s. Preparation of the silicon oxynitride layer: NH3, N2O and silane are introduced into the silicon oxynitride layer at 400℃~600℃, and the silicon oxynitride layer is obtained by plasma-enhanced chemical vapor deposition for 100 s~300 s. Preparation of the silicon oxide layer: N2O and silane are introduced into the silicon nitride layer at 400℃~600℃, and the silicon oxide layer is obtained by plasma-enhanced chemical vapor deposition for 100 s~200 s.
[0012] Furthermore, in the step of preparing the first antireflection layer on the first alumina layer, the silane includes SiH4 and has a power of 8000 W to 13500 W; In the step of preparing the silicon nitride layer, the flow rate of the silane is 1000 sccm to 4000 sccm, and the flow rate of the NH3 is 5000 sccm to 10000 sccm; In the step of preparing the silicon oxynitride layer, the flow rate of the silane is 1200 sccm~5000 sccm, the flow rate of the NH3 is 5000 sccm~10000 sccm, and the flow rate of the N2O is 4500 sccm~10000 sccm. In the step of preparing the silicon oxynitride layer, the flow rate of the silane is 1000 sccm to 3500 sccm, and the flow rate of the N2O is 5500 sccm to 12000 sccm.
[0013] Furthermore, after the step of irradiating the first alumina layer precursor with light to obtain the first alumina layer, and before the step of preparing the first antireflection layer on the first alumina layer, the preparation method further includes: A second alumina layer is prepared on the first alumina layer: a second aluminum source and water vapor are introduced at 220℃~400℃, and the second alumina layer is obtained by atomic layer deposition, wherein the pulse time is 5 s~25 s, the purging time is 5 s~25 s, and the number of cycles is 1 to 15.
[0014] Furthermore, in the step of preparing a second alumina layer on the first alumina layer, the second aluminum source includes trimethylaluminum, the flow rate of the second aluminum source is 10 sccm to 30 sccm, and the flow rate of the water vapor is 15 sccm to 30 sccm.
[0015] Thirdly, this application provides a photovoltaic module, the photovoltaic module comprising the solar cell as described in the first aspect, and / or the photovoltaic module comprising the solar cell prepared by the preparation method of the second aspect.
[0016] Compared with the prior art, the beneficial effects of this application are as follows: The solar cell of this application improves the resistance to ultraviolet degradation while improving the defects of the first doped layer by optimizing the ratio of the total hydrogen atom concentration A1 in the first doped layer and the substrate to the hydrogen atom concentration A2 in the first antireflection layer, thereby enhancing the photoelectric performance and lifespan of the solar cell.
[0017] The solar cell of this application includes a substrate and a first doped layer, a first aluminum oxide layer, and a first antireflection layer sequentially disposed on a first surface of the substrate. When the ratio of the hydrogen atom concentration A2 in the first antireflection layer to the total hydrogen atom concentration A1 of the first doped layer and the substrate is controlled within the range of (1.1~2.0):1.0, the overall hydrogen atom concentration level in the first doped layer and the substrate can be effectively improved, which is a significant improvement compared to the existing level.
[0018] Meanwhile, along the direction from the first doped layer towards the substrate, the overall hydrogen atom concentration in both the first doped layer and the substrate shows a decreasing trend. This means the hydrogen atom concentration is relatively higher in the region where the first doped layer is located and relatively lower in the region where the substrate is located. More specifically, the hydrogen atom concentration at the interface between the first doped layer and the first alumina layer is higher than the hydrogen atom concentration inside the first doped layer and the substrate. Given that the overall hydrogen atom concentration in both the first doped layer and the substrate is higher than existing levels, this implies that the hydrogen atom concentration at the interface between the first doped layer and the first alumina layer is also higher than existing levels. This increased hydrogen atom concentration at this location helps enhance the passivation effect at the interface between the first doped layer and the first alumina layer, thereby effectively suppressing carrier recombination, improving carrier transport efficiency, and enhancing the contact performance of the solar cell.
[0019] Furthermore, the first alumina layer disposed between the first doped layer and the first antireflection layer can not only further reduce the defect state density in the solar cell through the field passivation effect, but also effectively prevent hydrogen atoms in the first antireflection layer from diffusing into the cell. This structure effectively suppresses the formation of new carrier recombination centers by hydrogen atoms inside the solar cell, thereby significantly improving the solar cell's resistance to ultraviolet degradation. Attached Figure Description
[0020] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0021] Figure 1 This is a schematic diagram of the structure of the first type of solar cell provided in the embodiments of this application; Figure 2 This is a schematic diagram of the structure of the second type of solar cell provided in the embodiments of this application; Figure 3 This is a schematic diagram of the structure of the third type of solar cell provided in the embodiments of this application; Figure 4 This is a process flow diagram of the solar cell fabrication method according to an embodiment of this application; Figure 5 This is a SIMS curve of the solar cell receiving surface in Embodiment 1 of this application.
[0022] Explanation of reference numerals in the attached figures: 1. Substrate; 2. First doped layer; 3. First alumina layer; 4. First antireflection layer; 41. Silicon nitride layer; 42. Silicon oxynitride layer; 43. Silicon oxide layer; 5. Second alumina layer; 6. Dielectric layer; 7. Second doped layer; 8. Second antireflection layer; 91. First electrode; 92. Second electrode. Detailed Implementation
[0023] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0024] In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.
[0025] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.
[0026] Furthermore, the terms "installation," "setup," "equipped with," "connection," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.
[0027] Furthermore, the terms "first," "second," etc., are primarily used to distinguish different devices, components, or parts (which may be the same or different in specific type and construction), and are not intended to indicate or imply the relative importance or quantity of the indicated devices, components, or parts. Unless otherwise stated, "a plurality of" means two or more.
[0028] Defects exist in the doped layers of solar cells. These defects include structural flaws such as lattice dislocations, vacancies, and interstitial atoms on the surface of the doped layer. Lattice distortion leads to a large number of dangling bonds on the surface, affecting carrier transport. In addition, when the back of the solar cell is irradiated with ultraviolet light, the Si-H bonds in the outermost antireflection layer break, generating hydrogen atoms. These hydrogen atoms diffuse to the substrate and combine with existing impurities (such as oxygen and carbon) to form carrier recombination centers, further hindering carrier transport. Both of these factors causing impaired carrier transport negatively impact the photoelectric performance of the solar cell.
[0029] Based on the analysis of the causes of the above-mentioned technical problems, this application provides a solar cell and its preparation method, as well as a photovoltaic module, to solve this technical problem.
[0030] like Figure 1 As shown, this application provides a solar cell, which includes: The substrate 1 has a first surface and a second surface disposed opposite to each other; A first doped layer 2, a first alumina layer 3, and a first antireflection layer 4 are sequentially disposed on the first surface of the substrate 1. Along the direction from the first doped layer 2 toward the substrate 1, the hydrogen atom concentration in the first doped layer 2 and the substrate 1 shows a decreasing trend; the total hydrogen atom concentration in the first doped layer 2 and the substrate 1 is A1, the hydrogen atom concentration in the first antireflection layer 4 is A2, and the ratio of A2 to A1 is (1.1~2.0):1.0.
[0031] The hydrogen atom concentration was measured using an IONTOF TOF-SIMS 5-100 secondary ion mass spectrometer to obtain the SIMS curve. The horizontal axis of the SIMS curve represents the test time or the depth of the test sample, and the secondary ion count rate or atomic concentration of the analyte. In this application, the horizontal axis of the SIMS curve represents the diffusion depth of hydrogen atoms, and the vertical axis represents the hydrogen atom concentration. The SIMS curve reflects the distribution of hydrogen atoms in the solar cell. Integrating the corresponding regions of the first doped layer 2 and the substrate 1 yields the total hydrogen atom concentration A1 of the first doped layer 2 and the substrate 1. Integrating the corresponding region of the first antireflection layer 4 yields the hydrogen atom concentration A2 of the first antireflection layer 4.
[0032] For example, the ratio of A2 to A1 is 1.1:1.0, 1.3:1.0, 1.5:1.0, 1.7:1.0, 1.9:1.0, or 2.0:1.0. In this embodiment, the ratio of hydrogen atom concentration A2 in the first antireflection layer 4 to the total hydrogen atom concentration A1 of the first doped layer 2 and the substrate 1 is controlled within the range of (1.1~2.0):1.0. In existing solar cells, the ratio of A2 to A1 is in the range of (2.1~2.8):1.0, that is, the overall hydrogen atom concentration level in the first doped layer and the substrate is much lower in existing solar cells. In this embodiment, the overall hydrogen atom concentration level in the first doped layer 2 and the substrate 1 is improved. Preferably, A2:A1 = 1.65:1.0.
[0033] Among them, the direction of the first doped layer 2 toward the substrate 1 is... Figure 1 The hydrogen atom concentration in the first doped layer 2 and the substrate 1 decreases along a downward direction. This means the decreasing trend is continuous, not that each layer individually exhibits a decreasing trend. In other words, considering the first doped layer 2 and the substrate 1 as a whole, the hydrogen atom concentration decreases from the first doped layer 2 towards the substrate 1. This decreasing trend can be regular or irregular. For example, if the interface between the first doped layer 2 and the substrate 1 is defined as interface A, the hydrogen atom concentration in the region of the first doped layer 2 near interface A is higher than that in the region of the substrate 1 near interface A. In this embodiment, along the direction from the first doped layer 2 towards the substrate 1, the overall hydrogen atom concentration in the first doped layer 2 and the substrate 1 shows a decreasing trend. Specifically, the hydrogen atom concentration in the region of the first doped layer 2 is relatively higher, and the hydrogen atom concentration in the region of the substrate 1 is relatively lower. More specifically, the hydrogen atom concentration at the interface between the first doped layer 2 and the first alumina layer 3 is higher than the hydrogen atom concentration inside the first doped layer 2 and the substrate 1.
[0034] Given that the overall hydrogen atom concentration in the first doped layer 2 and the substrate 1 is increased compared to existing levels, this means that the hydrogen atom concentration at the interface between the first doped layer 2 and the first alumina layer 3 is also increased compared to existing levels. This increased hydrogen atom concentration at this location helps enhance the passivation effect at the interface between the first doped layer 2 and the first alumina layer 3, thereby effectively suppressing carrier recombination, improving carrier transport efficiency, and enhancing the contact performance of the solar cell.
[0035] Furthermore, the first alumina layer 3, located between the first doped layer 2 and the first antireflection layer 4, not only further reduces the defect state density in the solar cell through field passivation, but also effectively blocks the diffusion of hydrogen atoms from the first antireflection layer 4 into the cell. This structure effectively suppresses the formation of new carrier recombination centers by hydrogen atoms inside the solar cell, thereby significantly improving the solar cell's resistance to ultraviolet degradation.
[0036] Furthermore, A1 is 1.2 × 10 23 at / cm 3 ~1.8×10 23 at / cm 3 A2 is 1.9 × 10 23 at / cm 3 ~2.6×10 23 at / cm 3 For example, A1 is 1.2 × 10⁻⁶. 23 at / cm 3 1.4×10 23 at / cm 3 1.6×10 23 at / cm 3 Or 1.8×10 23 at / cm 3 A2 is 1.9 × 10 23 at / cm 3 2.2×10 23 at / cm 3 2.4×10 23 at / cm 3 Or 2.6×10 23 at / cm 3 In this embodiment, A1 is 1.2 × 10⁻⁶. 23 at / cm 3 ~1.8×10 23 at / cm 3 A2 is 1.9 × 10 23 at / cm 3 ~2.6×10 23 at / cm 3 In existing solar cells, A1 is 0.6 × 10⁻⁶. 23 at / cm 3 ~1.1×10 23 at / cm 3 A2 is 1.7 × 10 23 at / cm 3 ~2.25×10 23 at / cm 3In this embodiment, while A2 is comparable to that of the prior art, A1 is increased. Under the existing hydrogen atom concentration distribution pattern, the hydrogen atom concentration at the interface between the first doped layer 2 and the first alumina layer 3 is increased compared to the prior art. This increased hydrogen atom concentration at this location helps enhance the passivation effect at the interface between the first doped layer 2 and the first alumina layer 3, thereby effectively suppressing carrier recombination, improving carrier transport efficiency, and enhancing the contact performance of the solar cell. Preferably, A1 is 1.55 × 10⁻⁶. 23 at / cm 3 A2 is 2.56 × 10 23 at / cm 3 .
[0037] Furthermore, such as Figure 2 As shown, the solar cell also includes a second alumina layer 5, which is disposed between the first alumina layer 3 and the first antireflection layer 4. In this embodiment, the second alumina layer 5 further improves the field passivation effect of the solar cell. At the same time, the second alumina layer 5 can further suppress the diffusion of H atoms in the first antireflection layer 4, ensuring the antireflection effect of the solar cell and improving the solar cell's resistance to ultraviolet degradation.
[0038] Further, the thickness of the first alumina layer 3 is 2 mm to 8 nm; the thickness of the second alumina layer 5 is 1 mm to 4 nm. For example, the thickness of the first alumina layer 3 is 2 mm, 4 mm, 5 mm, 7 mm, or 8 nm, and the thickness of the second alumina layer 5 is 1 mm, 2 mm, 3 mm, or 4 nm. Preferably, the thickness of the first alumina layer 3 is 4 mm, and the thickness of the second alumina layer 5 is 2 mm. In this embodiment, when the thickness of the first alumina layer 3 is within the above range, it can effectively passivate defects at the interface between the film layer and the first doped layer 2, while avoiding poor contact performance of the solar cell due to excessive film thickness. When the thickness of the second alumina layer 5 is within the above range, it can effectively suppress the diffusion of H atoms in the first antireflection layer 4, without affecting the contact performance of the solar cell.
[0039] Furthermore, such as Figure 3As shown, the antireflection layer includes a silicon nitride layer 41, a silicon oxynitride layer 42, and a silicon oxide layer 43 sequentially disposed on the surface of the first doped layer 2 facing away from the substrate 1. In this embodiment, the first antireflection layer 4, composed of three layers of different materials, can cover a wider spectrum through a gradient refractive index design, resulting in lower reflectivity of the three-layer antireflection layer 4: the refractive index of the silicon oxide layer 43 is approximately 1.45, close to the refractive index of air (1.0), reducing reflection between air and the film layer; the refractive index of the silicon nitride layer 41 is approximately 2.0, better matching the refractive index of the first doped layer 2 (3.4~3.8), further reducing reflection between the film layer and the surface of the first doped layer 2; the refractive index of the silicon oxynitride layer 42 is 1.6~2.0; the placement between the silicon nitride layer 41 and the silicon oxide layer 43 can avoid additional reflection caused by abrupt changes in refractive index; the three-layer film structure composed of three different materials can also increase the stability of the first antireflection layer 4 and improve the environmental stability of the solar cell.
[0040] Furthermore, such as Figure 3 As shown, the solar cell is a passivated contact cell. The first surface is the light-receiving surface, and the second surface is the backlighting surface. The light-receiving surface is sequentially provided with a first doped layer 2, a first aluminum oxide layer 3, a second aluminum oxide layer 5, a first antireflection layer 4, and a first electrode 91. The backlighting surface is sequentially provided with a dielectric layer 6, a second doped layer 7, a second antireflection layer 8, and a second electrode 92. The first doped layer 2 and the second doped layer 7 have opposite conductivity types, and one of the first electrode 91 and the second electrode 92 is a positive electrode, while the other is a negative electrode. As an optional embodiment, the substrate 1 is an N-type silicon substrate 1, the first doped layer 2 is a P-type doped layer, and the second doped layer 7 is an N-type doped layer. As another optional embodiment, when the substrate 1 is a P-type silicon substrate 1, the first doped layer 2 is an N-type doped layer, and the second doped layer 7 is a P-type doped layer.
[0041] In addition to the solar cells described above, the solar cells of this application can also be a portion of a tandem solar cell or a heterojunction solar cell. For example, when the tandem solar cell is a perovskite tandem solar cell, the solar cell of this application can serve as the bottom cell in the perovskite tandem solar cell.
[0042] This application also provides a method for preparing the above-described solar cell. It is understood that this preparation method is one way to obtain the solar cell described in this application, but it is not limited to the only method. That is, the solar cell described in this application can also be prepared by other methods, and this application does not impose any limitations on this. Therefore, it should not be construed as a limitation on the solar cell provided in this application.
[0043] like Figure 4 As shown, the preparation method includes the following steps: A first alumina layer precursor is prepared on a substrate 1 having a first doped layer 2; wherein the substrate 1 has a first surface and a second surface disposed opposite to each other, the first doped layer 2 is disposed on the first surface, and the first alumina layer precursor is prepared on the side of the first doped layer 2 opposite to the substrate 1. The precursor of the first alumina layer is irradiated with light to obtain the first alumina layer 3; wherein the process conditions for light irradiation include: light wavelength of 180 nm to 280 nm, light intensity of 80 W / cm² to 220 W / cm², and light irradiation time of 0.1 s to 80 s; A first antireflection layer 4 is prepared on the first alumina layer 3.
[0044] For example, the light wavelength is 180 nm, 210 nm, 240 nm, 270 nm or 280 nm, the light intensity is 80 W / cm², 110 W / cm², 140 W / cm², 190 W / cm², 210 W / cm² or 220 W / cm², and the illumination time is 0.1 s, 1 s, 6 s, 25 s, 37 s, 53 s, 72 s or 80 s.
[0045] In this embodiment, before preparing the first antireflection layer 4, a step of irradiating the first alumina layer precursor with light is added. This changes the hydrogen atom concentration in the first alumina layer precursor, resulting in a first alumina layer 3 made of the same material but with a different hydrogen atom concentration in the film. The energy generated by the light irradiation process causes the Al-H and Al-OH bonds in the first alumina layer precursor to break. Driven by the concentration difference, the resulting hydrogen atoms diffuse from the first alumina layer precursor towards the first doped layer 2, resulting in the first alumina layer 3. The first alumina layer 3 contains fewer hydrogen atoms than the first alumina layer precursor. During the use of the solar cell, ultraviolet irradiation causes the Si-H bonds in the first antireflection layer 4 to break. Since the first alumina layer 3 has fewer hydrogen atoms, it has a better cutoff effect on the hydrogen in the first antireflection layer 4, reducing the possibility of hydrogen atoms in the first antireflection layer 4 diffusing into the cell to form new carrier recombination centers, thus improving the solar cell's resistance to ultraviolet degradation. Simultaneously, the diffused hydrogen atoms cause the hydrogen atom concentration in the first doped layer 2 and the substrate 1 in the solar cell to decrease along a predetermined direction. The hydrogen atom concentration at the interface between the first doped layer 2 and the first alumina layer 3 is higher, which can better passivate defects at the interface and improve the carrier transport efficiency. Preferably, the light wavelength is 210 nm to 260 nm, the light intensity is 120 W / cm² to 180 W / cm², and the illumination time is 1 s to 15 s.
[0046] Further, the total hydrogen atom concentration in the first doped layer 2 and the substrate 1 is A1, and the hydrogen atom concentration in the first antireflection layer 4 is A2, with A2:A1 being (1.1~2.0):1.0. For example, the ratio of A1 to A2 is 1.1:1.0, 1.3:1.0, 1.5:1.0, 1.7:1.0, 1.9:1.0, or 2.0:1.0. In this embodiment, when the ratio of A2 to A1 is controlled within the range of (1.1~2.0):1.0, the overall hydrogen atom concentration level in the first doped layer 2 and the substrate 1 is increased. Since the hydrogen atom concentration level decreases from the first doped layer 2 to the substrate 1, the hydrogen atom concentration at the interface between the first doped layer 2 and the first alumina layer 3 is increased to a certain extent, enhancing the passivation effect at the interface between the first doped layer 2 and the first alumina layer 3, thereby effectively suppressing carrier recombination, improving carrier transport efficiency, and improving the contact performance of the solar cell. Preferably, A2:A1 = 1.65:1.0.
[0047] Furthermore, A1 is 1.2 × 10 23 at / cm 3 ~1.8×10 23 at / cm 3 For example, A1 is 1.2 × 10⁻⁶. 23 at / cm 3 1.4×10 23 at / cm 3 1.6×10 23 at / cm 3 Or 1.8×10 23 at / cm 3 A2 is 1.9 × 10 23 at / cm 3 2.2×10 23 at / cm 3 2.4×10 23 at / cm 3 Or 2.6×10 23 at / cm 3 In this embodiment, while A2 is comparable to that of the prior art, A1 is increased. Since the concentration of hydrogen atoms decreases from the first doped layer 2 towards the substrate 1, the hydrogen atom concentration at the interface between the first doped layer 2 and the first alumina layer 3 is increased compared to existing levels. This increased hydrogen atom concentration at this location helps enhance the passivation effect at the interface between the first doped layer 2 and the first alumina layer 3, thereby effectively suppressing carrier recombination, improving carrier transport efficiency, and enhancing the contact performance of the solar cell. Preferably, A1 is 1.55 × 10⁻⁶. 23 at / cm 3 A2 is 2.56 × 1023 at / cm 3 .
[0048] Further, the step of preparing the first alumina layer precursor on the substrate 1 having the first doped layer 2 includes: introducing a first aluminum source and water vapor into the first doped layer 2 at 200℃~350℃, and obtaining the first alumina layer precursor by atomic layer deposition, wherein the pulse time is 1 s~15 s, the purge time is 5 s~25 s, and the number of cycles is 20~45.
[0049] The first aluminum source includes trimethylaluminum. Exemplarily, the temperature of this step is 200°C, 230°C, 260°C, 290°C, 310°C, or 350°C; the pulse duration is 1 s, 4 s, 8 s, 11 s, 13 s, or 15 s; the purging time is 5 s, 9 s, 13 s, 17 s, 19 s, 22 s, or 25 s; and the number of cycles is 20, 23, 27, 31, 35, 38, 42, or 45. Preferably, the temperature of this step is 230°C to 280°C; the pulse duration is 6 s to 12 s; the purging time is 10 s to 20 s; and the number of cycles is 20 to 35.
[0050] Further, the flow rate of the first aluminum source is 10 sccm to 30 sccm, and the flow rate of the water vapor is 15 sccm to 30 sccm. For example, the flow rate of the first aluminum source is 10 sccm, 15 sccm, 20 sccm, 20 sccm, or 30 sccm, and the flow rate of the water vapor is 15 sccm, 20 sccm, 25 sccm, or 30 sccm. Preferably, the flow rate of the first aluminum source is 15 sccm to 25 sccm, and the flow rate of the water vapor is 17 sccm to 24 sccm.
[0051] Furthermore, after the step of obtaining the first alumina layer 3 by irradiating the first alumina layer precursor with light, and before the step of preparing the first antireflection layer 4 on the first alumina layer 3, the preparation method further includes: A second alumina layer 5 is prepared on the first alumina layer 3: a second aluminum source and water vapor are introduced at 220℃~400℃, and the second alumina layer 5 is obtained by atomic layer deposition, wherein the pulse time is 5 s~25 s, the purging time is 5 s~25 s, and the number of cycles is 1 to 15.
[0052] The second aluminum source includes trimethylaluminum. Exemplarily, the temperature in this step is 220°C, 260°C, 280°C, 310°C, 360°C, or 400°C; the pulse duration is 5 s, 8 s, 13 s, 16 s, 20 s, 23 s, or 25 s; the purging time is 5 s, 9 s, 13 s, 17 s, 19 s, 22 s, or 25 s; and the number of cycles is 1, 4, 8, 11, 13, or 15. Preferably, the temperature in this step is 280°C to 330°C; the pulse duration is 10 s to 15 s; the purging time is 10 s to 15 s; and the number of cycles is 5 to 10. In this embodiment, the temperature during the preparation of the second alumina layer 5 is higher than that during the preparation of the first alumina layer 3, resulting in a lower H atom content in the formed second alumina layer 5, which better suppresses the diffusion of H atoms in the first antireflection layer 4 and ensures the antireflection effect of the solar cell.
[0053] Further, the flow rate of the second aluminum source is 10 sccm to 30 sccm, and the flow rate of the water vapor is 15 sccm to 30 sccm. For example, the flow rate of the second aluminum source is 10 sccm, 15 sccm, 20 sccm, 20 sccm, or 30 sccm, and the flow rate of the water vapor is 15 sccm, 20 sccm, 25 sccm, or 30 sccm. Preferably, the flow rate of the second aluminum source is 20 sccm, and the flow rate of the water vapor is 22 sccm.
[0054] Furthermore, the first antireflection layer 4 includes a silicon nitride layer 41, a silicon oxynitride layer 42, and a silicon oxide layer 43. The step of preparing the first antireflection layer 4 on the first aluminum oxide layer 3 includes: preparing the silicon nitride layer 41, preparing the silicon oxynitride layer 42, and preparing the silicon oxide layer 43.
[0055] The step of preparing the silicon nitride layer 41 includes: introducing NH3 and silane into the first alumina layer 3 at 400℃~600℃, and then treating it by plasma-enhanced chemical vapor deposition for 50 s~200 s to obtain the silicon nitride layer 41.
[0056] The silane includes SiH4, and the power is 8000 W to 13500 W. Exemplarily, the temperature of this step is 400°C, 450°C, 500°C, 550°C, or 600°C, the processing time is 50 s, 80 s, 130 s, 160 s, 180 s, or 200 s, and the power is 8000 W, 9000 W, 10500 W, 12000 W, or 13500 W. Preferably, the temperature of this step is 450°C to 550°C, the processing time is 110 s to 140 s, and the power is 9500 W to 12000 W.
[0057] Further, in the step of preparing the silicon nitride layer 41, the flow rate of silane is 1000 sccm to 4000 sccm, and the flow rate of NH3 is 5000 sccm to 10000 sccm. Exemplarily, the flow rate of silane is 1000 sccm, 2000 sccm, 3000 sccm, or 4000 sccm, and the flow rate of NH3 is 5000 sccm, 6000 sccm, 7500 sccm, 9000 sccm, or 10000 sccm. Preferably, the flow rate of silane is 2000 sccm to 3000 sccm, and the flow rate of NH3 is 6000 sccm to 8000 sccm.
[0058] The steps for preparing the silicon oxynitride layer 42 include: introducing NH3, N2O and silane into the silicon oxynitride layer 41 at 400℃~600℃, and then treating it by plasma-enhanced chemical vapor deposition for 100 s~300 s to obtain the silicon oxynitride layer 42.
[0059] The silane includes SiH4, and the power is 8000 W to 13500 W. Exemplarily, the temperature of this step is 400°C, 450°C, 500°C, 550°C, or 600°C, the processing time is 100 s, 150 s, 190 s, 240 s, 290 s, 320 s, 370 s, or 400 s, and the power is 8000 W, 9000 W, 10500 W, 12000 W, or 13500 W. Preferably, the temperature of this step is 450°C to 550°C, the processing time is 150 s to 250 s, and the power is 9500 W to 11500 W.
[0060] Further, the flow rate of silane is 1200 sccm to 5000 sccm, the flow rate of NH3 is 5000 sccm to 10000 sccm, and the flow rate of N2O is 4500 sccm to 10000 sccm. For example, the flow rate of silane is 1200 sccm, 2300 sccm, 3500 sccm, 4600 sccm, or 5000 sccm; the flow rate of NH3 is 5000 sccm, 6000 sccm, 7500 sccm, 9000 sccm, or 10000 sccm; and the flow rate of N2O is 4500 sccm, 6000 sccm, 7500 sccm, 9000 sccm, or 10000 sccm. Preferably, the flow rate of silane is 2500 sccm to 4000 sccm, the flow rate of NH3 is 6500 sccm to 8000 sccm, and the flow rate of N2O is 6000 sccm to 7500 sccm.
[0061] The steps for preparing the silicon oxide layer 43 include: introducing N2O and silane into the silicon nitride layer 41 at 400℃~600℃, and then treating it by plasma-enhanced chemical vapor deposition for 100 s~200 s to obtain the silicon oxide layer 43.
[0062] The silane includes SiH4, and the power is 8000 W to 13500 W. Exemplarily, the temperature of this step is 400°C, 450°C, 500°C, 550°C, or 600°C, the processing time is 100 s, 150 s, 190 s, or 200 s, and the power is 8000 W, 9000 W, 10500 W, 12000 W, or 13500 W. Preferably, the temperature of this step is 450°C to 550°C, the processing time is 120 s to 170 s, and the power is 10000 W to 12500 W.
[0063] Further, the flow rate of silane is 1000 sccm to 3500 sccm, and the flow rate of N2O is 5500 sccm to 12000 sccm. Exemplarily, the flow rate of silane is 1000 sccm, 1600 sccm, 2100 sccm, 2800 sccm, or 3500 sccm, and the flow rate of N2O is 5500 sccm, 7500 sccm, 8000 sccm, 9500 sccm, or 12000 sccm. Preferably, the flow rate of silane is 1750 sccm to 2500 sccm, and the flow rate of N2O is 7000 sccm to 9500 sccm.
[0064] This application also provides a photovoltaic module. The photovoltaic module includes the aforementioned solar cell, or the photovoltaic module further includes a solar cell prepared by the aforementioned solar cell preparation method, or the photovoltaic module simultaneously includes the aforementioned solar cell and a solar cell prepared by the aforementioned solar cell preparation method.
[0065] The technical solution of this application will be further explained below with reference to more specific embodiments and experimental test results.
[0066] Example 1 This application provides a passivated contact battery, the preparation steps of which include: Step 1: Deposit a 100 nm boron-containing amorphous silicon layer on the light-receiving surface of the substrate, and then anneal to obtain the first doped layer; Step 2: Etch, clean, and polish the back surface of the substrate; Step 3: Deposit a 1.2 nm silicon oxide layer as a dielectric layer on the back surface of the substrate; Step 4: Deposit a 100 nm phosphorus-containing amorphous silicon layer on the dielectric layer, and then anneal to obtain the second doped layer; Step 5: Clean to remove oxides on both sides and the edge coating; Step 6: Prepare the first alumina layer precursor on the first doped layer: At 250°C, trimethylaluminum and water vapor are introduced into the first doped layer, and the first alumina layer precursor is obtained by atomic layer deposition. The pulse time is 9 s, the purge time is 15 s, the trimethylaluminum flow rate is 20 sccm, the water vapor flow rate is 20 sccm, the number of cycles is 30, and the thickness of the first alumina layer precursor is 4 nm. Step 7: Irradiate the first alumina layer precursor with light of wavelength 235 nm and intensity 160 W / cm² for 1.5 s to obtain the first alumina layer; Step 8: At 300°C, trimethylaluminum and water vapor are introduced into the first silicon oxide layer, and a second aluminum oxide layer is obtained by atomic layer deposition. The pulse time is 12 s, the purge time is 13 s, the trimethylaluminum flow rate is 20 sccm, the water vapor flow rate is 22 sccm, the number of cycles is 7, and the thickness of the second aluminum oxide layer is 1.5 nm. Step 9: At 500℃, NH3 and silane are introduced into the second alumina layer on the light-receiving side and the second doped layer on the back-light side. The mixture is then subjected to plasma-enhanced chemical vapor deposition for 120 s at a power of 11000 W, a flow rate of 7000 sccm for NH3, and a flow rate of 2500 sccm for silane. A silicon nitride layer with a thickness of 25 nm is obtained on the second alumina layer, and a silicon nitride layer with a thickness of 75 nm is obtained on the second doped layer as the second antireflection layer. Step 10: At 500℃, NH3, N2O and silane are introduced into the silicon nitride layer on the light-receiving surface, and plasma-enhanced chemical vapor deposition is performed for 150 s with a power of 10500 W, a flow rate of 3500 sccm for NH3, a flow rate of 700 sccm for NO2 and a flow rate of 7500 sccm for silane, to obtain a silicon oxynitride layer with a thickness of 30 nm. Step 11: At 500℃, N2O and silane were introduced into the silicon oxynitride layer, and plasma-enhanced chemical vapor deposition was performed for 150 s with a power of 11500 W, a NO2 flow rate of 8500 sccm, and a silane flow rate of 2200 sccm to obtain a silicon oxynitride layer with a thickness of 30 nm. Step 12: Form the first electrode and the second electrode.
[0067] Example 2 The difference between this embodiment and Embodiment 1 is that step 8 is not included.
[0068] Example 3 The difference between this embodiment and Embodiment 1 is that the thickness of the second alumina layer is 4 nm.
[0069] Example 4 The difference between this embodiment and Embodiment 1 is that the thickness of the second alumina layer is 6 nm.
[0070] Example 5 The difference between this embodiment and Embodiment 1 is that the thickness of the first alumina layer is 8 nm.
[0071] Example 6 The difference between this embodiment and Embodiment 1 is that the thickness of the first alumina layer is 2 nm.
[0072] Example 7 The difference between this embodiment and Embodiment 1 is that the thickness of the first alumina layer is 10 nm.
[0073] Example 8 The difference between this embodiment and Embodiment 1 is that the thickness of the first alumina layer is 1 nm.
[0074] Comparative Example The difference between this comparative example and Example 1 is that steps 7 and 8 are not included.
[0075] Performance testing: 1. Determination of hydrogen atom concentration in the first doped layer SIMS curves for Examples 1-8 and the comparative example were obtained using an IONTOF TOF-SIMS 5-100 secondary ion mass spectrometer. The SIMS curve for Example 1 is shown below. Figure 5 As shown, the depth corresponding to the first doped layer is the difference between the x-coordinate of the highest point of the curve and the end point of the curve in the figure. The x-coordinate of the end point of the curve is 200 nm. Integrating, the total hydrogen atom concentration A1 in the first doped layer and the substrate of Example 1 is 1.55 × 10⁻⁶. 23 at / cm 3 The hydrogen atom concentration A2 in the first antireflection layer is 2.56 × 10⁻⁶. 23 at / cm 3 The hydrogen atom concentrations of Examples 2-3 and the comparative examples were obtained using the same method. The hydrogen atom concentration results of Examples 1-8 and the comparative examples are shown in Table 1.
[0076] 2. Photoelectric performance testing Performance tests, including open-circuit voltage, fill factor, and photoelectric conversion efficiency, were conducted on Examples 1-8 and the comparative example using the Halm testing and sorting equipment. The Halm machine is a device that simulates sunlight, equipped with electronic loads, data acquisition and calculation equipment, and is used to test the electrical performance of photovoltaic devices (including solar cells). The calibrated light intensity of the solar cells under test was controlled at 1000±5 W / m². The test results are shown in Table 2.
[0077] 3. UV attenuation resistance test The solar cells of Examples 1 to 8 and the comparative examples were tested through the following steps: Using ultraviolet light of 280 nm to 400 nm, under dry conditions at 50 °C to 60 °C, at a concentration of 60 kWh / m 2 The irradiance was continuously tested for 1000 hours. The photoelectric conversion efficiency of the solar cells before and after the UV60 test was detected and recorded. The UV decay rate of UV60 was calculated based on the formula: UV decay rate = Photoelectric conversion efficiency of the solar cells before UV60 test - Photoelectric conversion efficiency of the solar cells after UV60 test.
[0078] Table 1. Test results of hydrogen atom concentration in Examples 1-8 and the comparative examples.
[0079] Table 2. Results of photoelectric properties and UV degradation resistance of Examples 1-8 and comparative examples.
[0080] By comparing Examples 1 to 8 and the comparative example, it can be seen that the A2:A1 ratio in Examples 1 to 8 of this application is within the range of (1.1~2.0):1.0, which can effectively increase the total hydrogen atom concentration A1 in the first doped layer and the substrate. The increase in hydrogen atoms improves the passivation effect on defects. Therefore, the photoelectric performance of the embodiments of this application is better than that of the comparative example. In particular, by further comparing Example 2 and the comparative example, when the hydrogen atom concentration A2 in the first antireflection layer is similar, the total hydrogen atom concentration A1 in the first doped layer and the substrate of Example 2 is higher, which can better passivate defects at the interface and improve the carrier transport efficiency. The UV60 degradation rate of the solar cells in the embodiments of this application is less than 2.0%, which meets the production requirements of solar cells, while the UV60 degradation rate of the solar cells in the comparative example is higher than 2.0%, indicating that their anti-ultraviolet degradation effect is poor.
[0081] By comparing Example 1 and Example 2, it can be seen that Example 1 contains a second alumina layer, which can further suppress the diffusion of H atoms in the first antireflection layer, ensure the antireflection effect of the solar cell, and improve the anti-ultraviolet degradation performance of the solar cell.
[0082] Comparing Examples 1, 3, and 4, it can be seen that as the thickness of the second alumina layer increases, the effect of suppressing the diffusion of H atoms in the first antireflection layer is better. When the thickness of the second alumina layer is between 1 mm and 4 mm, it can suppress the diffusion of H atoms in the first antireflection layer without causing a decrease in the contact performance of the solar cell, thereby improving both the photoelectric performance and the anti-ultraviolet degradation performance of the solar cell.
[0083] Comparing Examples 1 and 5-8, it can be seen that when the thickness of the first alumina layer is within the preferred range of 2 mm to 8 nm, the total hydrogen atom concentration A1 in the first doped layer and the substrate is higher with increasing thickness of the first alumina layer. This results in better passivation of defects at the interface between the first alumina layer and the first doped layer, and at the same time, it also enables the solar cell to have good contact performance, further improving the photoelectric conversion efficiency of the solar cell. When the thickness of the first alumina layer is within the above range, it can also further reduce the diffusion of H atoms in the antireflection layer, improving the solar cell's resistance to ultraviolet degradation.
[0084] The technical solutions disclosed in the embodiments of this application have been described in detail above. Specific examples have been used in this article to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the technical solutions and core inventive points of the embodiments of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.
Claims
1. A solar cell, characterized in that, The solar cell includes: The substrate has a first surface and a second surface disposed opposite to each other; A first doped layer, a first alumina layer, and a first antireflection layer are sequentially disposed on the first surface of the substrate; Along the direction from the first doped layer toward the substrate, the hydrogen atom concentration in the first doped layer and the substrate shows a decreasing trend; the total hydrogen atom concentration in the first doped layer and the substrate is A1, the hydrogen atom concentration in the first antireflection layer is A2, and the ratio of A2 to A1 is (1.1~2.0):1.
0.
2. The solar cell according to claim 1, characterized in that, The value of A1 is 1.2 × 10⁻⁶. 23 at / cm 3 ~1.8×10 23 at / cm 3 The value of A2 is 1.9 × 10⁻⁶. 23 at / cm 3 ~2.6×10 23 at / cm 3 .
3. The solar cell according to claim 1, characterized in that, The solar cell also includes a second aluminum oxide layer, which is disposed between the first aluminum oxide layer and the first antireflection layer.
4. A method for fabricating a solar cell, characterized in that, The preparation method includes: A first alumina layer precursor is prepared on a substrate having a first doped layer; wherein the substrate has a first surface and a second surface disposed opposite to each other, the first doped layer is disposed on the first surface, and the first alumina layer precursor is prepared on the side of the first doped layer opposite to the substrate. The first alumina layer precursor is irradiated with light to obtain the first alumina layer; wherein the process conditions for light irradiation include: light wavelength of 180 nm to 280 nm, light intensity of 80 W / cm² to 220 W / cm², and light irradiation time of 0.1 s to 80 s; A first antireflection layer is prepared on the first alumina layer.
5. The preparation method according to claim 4, characterized in that, The total hydrogen atom concentration in the first doped layer and the substrate is A1, and the hydrogen atom concentration in the first antireflection layer is A2, where A2:A1 is (1.1~2.0):1.0; and / or, The value of A1 is 1.2 × 10⁻⁶. 23 at / cm 3 ~1.8×10 23 at / cm 3 The value of A2 is 1.9 × 10⁻⁶. 23 at / cm 3 ~2.6×10 23 at / cm 3 .
6. The preparation method according to claim 4, characterized in that, The step of preparing the first alumina layer precursor on a substrate having a first doped layer includes: introducing a first aluminum source and water vapor into the first doped layer at 200℃~350℃, and obtaining the first alumina layer precursor by atomic layer deposition, wherein the pulse time is 1 s~15 s, the purge time is 5 s~25 s, and the number of cycles is 20~45.
7. The preparation method according to claim 6, characterized in that, The first aluminum source includes trimethylaluminum, the flow rate of the first aluminum source is 10 sccm to 30 sccm, and the flow rate of the water vapor is 15 sccm to 30 sccm.
8. The preparation method according to claim 4, characterized in that, The first antireflection layer includes a silicon nitride layer, a silicon oxynitride layer, and a silicon oxide layer. The step of preparing the first antireflection layer on the first aluminum oxide layer includes: Preparation of the silicon nitride layer: NH3 and silane are introduced into the first alumina layer at 400℃~600℃, and the silicon nitride layer is obtained by plasma-enhanced chemical vapor deposition for 50 s~200 s. Preparation of the silicon oxynitride layer: NH3, N2O and silane are introduced into the silicon oxynitride layer at 400℃~600℃, and the silicon oxynitride layer is obtained by plasma-enhanced chemical vapor deposition for 100 s~300 s. Preparation of the silicon oxide layer: N2O and silane are introduced into the silicon nitride layer at 400℃~600℃, and the silicon oxide layer is obtained by plasma-enhanced chemical vapor deposition for 100 s~200 s.
9. The preparation method according to claim 8, characterized in that, In the step of preparing the first antireflection layer on the first alumina layer, the silane includes SiH4, and the power is 8000 W~13500 W; In the step of preparing the silicon nitride layer, the flow rate of the silane is 1000 sccm to 4000 sccm, and the flow rate of the NH3 is 5000 sccm to 10000 sccm; In the step of preparing the silicon oxynitride layer, the flow rate of the silane is 1200 sccm~5000 sccm, the flow rate of the NH3 is 5000 sccm~10000 sccm, and the flow rate of the N2O is 4500 sccm~10000 sccm. In the step of preparing the silicon oxynitride layer, the flow rate of the silane is 1000 sccm to 3500 sccm, and the flow rate of the N2O is 5500 sccm to 12000 sccm.
10. The preparation method according to claim 4, characterized in that, After the step of irradiating the first alumina layer precursor with light to obtain the first alumina layer, and before the step of preparing the first antireflection layer on the first alumina layer, the preparation method further includes: A second alumina layer is prepared on the first alumina layer: a second aluminum source and water vapor are introduced at 220℃~400℃, and the second alumina layer is obtained by atomic layer deposition, wherein the pulse time is 5 s~25 s, the purging time is 5 s~25 s, and the number of cycles is 1 to 15.
11. The preparation method according to claim 10, characterized in that, In the step of preparing a second alumina layer on the first alumina layer, the second aluminum source includes trimethylaluminum, the flow rate of the second aluminum source is 10 sccm to 30 sccm, and the flow rate of the water vapor is 15 sccm to 30 sccm.
12. A photovoltaic module, characterized in that, The photovoltaic module includes a solar cell as described in any one of claims 1-3, and / or the photovoltaic module includes a solar cell prepared by the preparation method described in any one of claims 4-11.