Laminated solar cell and photovoltaic module

Abstract

The invention discloses a laminated solar cell and a photovoltaic module. The laminated solar cell comprises a crystalline silicon top cell, a self-adaptive light conversion layer, an ultraviolet light reflection layer and a perovskite bottom cell which are sequentially laminated. Therefore, the absorption layer of the perovskite bottom cell is not easily influenced by ultraviolet light, the stability of the laminated solar cell is improved, and the service life of the laminated solar cell is prolonged; moreover, the laminated solar cell can dynamically adapt to the change of sunlight intensity, and the utilization rate of spectral energy is improved, so that the all-weather generating capacity is improved.

Description

Technical Field

[0001] This application relates to the field of solar cell technology, and more specifically, to tandem solar cells and photovoltaic modules. Background Technology

[0002] Solar photovoltaic technology is one of the core technologies for addressing global energy challenges. Among them, perovskite / crystalline silicon tandem solar cells have become the forefront of next-generation photovoltaic technology due to their extremely high theoretical efficiency. Tandem cells combine a wide-bandgap perovskite top cell with a narrow-bandgap crystalline silicon bottom cell, complementing each other's absorption of the solar spectrum, thus overcoming the efficiency bottleneck of single-junction cells. However, the commercialization of perovskite materials faces a core bottleneck: ultraviolet light instability. Ultraviolet light with wavelengths less than 400 nanometers can induce degradation in perovskite materials, resulting in poor stability and short lifespan of perovskite / crystalline silicon tandem solar cells. In addition, current tandem solar cells have low light energy utilization efficiency, poor environmental adaptability, and limited practical application scenarios.

[0003] Therefore, current tandem solar cells and photovoltaic modules still need improvement. Summary of the Invention

[0004] This application aims to at least partially alleviate or resolve at least one of the aforementioned problems.

[0005] In one aspect of this application, a tandem solar cell is proposed. In some embodiments of this application, the tandem solar cell includes a crystalline silicon top cell, an adaptive light conversion layer, an ultraviolet light reflective layer, and a perovskite bottom cell stacked sequentially. Therefore, the absorption layer of the perovskite bottom cell is less susceptible to ultraviolet light, which helps improve the stability of the tandem solar cell and thus extends its lifespan. Furthermore, the tandem solar cell can dynamically adapt to changes in sunlight intensity, improving the utilization rate of spectral energy and thereby increasing all-weather power generation.

[0006] In some embodiments of this application, the adaptive light conversion layer includes a first substrate and a first quantum dot. The first quantum dot is dispersed in the first substrate and is doped with an activator and a sensitizer. The activator includes one or more of erbium ions, thulium ions, holmium ions, europium ions, terbium ions, cerium ions, and dysprosium ions, and the sensitizer includes ytterbium ions. The sensitizer can form an effective energy level coupling with the first quantum dot, maximizing the capture of energy transferred from the first quantum dot, and then efficiently transferring the energy to the activator. The activator then achieves spectral conversion through upconversion or downconversion effects, thereby improving the utilization rate of spectral energy.

[0007] In some embodiments of this application, the adaptive light conversion layer satisfies at least one of the following conditions: the first substrate comprises one or more of silicon oxide, fluoride glass, and fluorinated polymer; the first quantum dot comprises one or more of zinc oxide quantum dots, carbon quantum dots, and perovskite quantum dots; the activator comprises one or more of erbium ions, thulium ions, and holmium ions, and the activator comprises one or more of europium ions, terbium ions, cerium ions, and dysprosium ions; the first quantum dot is further doped with a bridging agent, optionally, the bridging agent comprises gadolinium ions; and the mass content of the first quantum dot is 0.1%-10% based on the total mass of the adaptive light conversion layer.

[0008] In some embodiments of this application, the first quantum dot comprises Zn (1-a-x-y) Gd a Yb x M y O, where M is selected from one or more of erbium ions, thulium ions, holmium ions, europium ions, terbium ions, cerium ions, and dysprosium ions, and 0.005≤a≤0.05, 0.01≤x≤0.15, 0.001≤y≤0.07. Therefore, the adaptive light conversion layer can adaptively adjust according to changes in the intensity of incident sunlight, enabling the tandem solar cell to maintain high photoelectric conversion efficiency under both low-light and high-light conditions.

[0009] In some embodiments of this application, the adaptive light conversion layer includes a second substrate, a second quantum dot, and a rare earth complex. The second quantum dot and the rare earth complex are dispersed in the second substrate. The rare earth complex includes rare earth ions and organic ligands. The rare earth ions include one or more of erbium ions, thulium ions, holmium ions, europium ions, terbium ions, cerium ions, and dysprosium ions. This adaptive light conversion layer can also adapt to changes in the intensity of incident sunlight, enabling the tandem solar cell to maintain high photoelectric conversion efficiency under different environments.

[0010] In some embodiments of this application, the adaptive light conversion layer satisfies at least one of the following conditions: the second substrate comprises one or more of silicon oxide, fluoride glass, and fluorinated polymer; the second quantum dot comprises one or more of zinc oxide quantum dots, carbon quantum dots, and perovskite quantum dots; the rare earth ions comprise one or more of erbium ions, thulium ions, and holmium ions, and the rare earth ions comprise one or more of europium ions, terbium ions, cerium ions, and dysprosium ions; the organic ligand comprises one or more of β-diketones, carboxylic acids, and imidazoles.

[0011] In some embodiments of this application, the thickness of the adaptive light conversion layer is 100nm-100μm.

[0012] In some embodiments of this application, the ultraviolet reflective layer includes alternating layers of a first sublayer and a second sublayer, wherein the refractive index of the first sublayer is greater than that of the second sublayer, and the sublayer closest to the crystalline silicon top cell in the ultraviolet reflective layer is the first sublayer. The ultraviolet reflective layer can reflect ultraviolet light incident upon it, reducing the adverse effects of ultraviolet light on the perovskite absorption layer, thereby improving the stability of the tandem solar cell.

[0013] In some embodiments of this application, the first sublayer comprises one or more of titanium oxide, hafnium oxide, and tantalum oxide; and / or, the second sublayer comprises silicon oxide.

[0014] In some embodiments of this application, the tandem solar cell is a four-terminal structure cell. The top and bottom cells of the four-terminal structure cell are independent, without current matching limitations, and can be optimized independently, which is beneficial to maximizing the performance of the tandem cell; the process is flexible, the fault tolerance is high, and it has greater industrialization potential.

[0015] In some embodiments of this application, the tandem solar cell further includes a bottom cell encapsulation layer. Therefore, the encapsulation layer can at least partially isolate water, oxygen, and scattered ultraviolet light, further reducing the adverse effects of external water, oxygen, and ultraviolet light on the perovskite cell, thereby contributing to further improvement in the stability of the tandem solar cell.

[0016] In some embodiments of this application, the bottom cell encapsulation layer includes a Parylene C sublayer, an alumina sublayer, and a silicon oxide sublayer stacked sequentially, with the silicon oxide sublayer located on the side of the alumina sublayer closer to the perovskite bottom cell. This encapsulation layer effectively isolates water, oxygen, and scatters ultraviolet light, thereby contributing to further improvements in the stability of the tandem solar cell.

[0017] In another aspect of this application, a photovoltaic module is proposed. In some embodiments of this application, the photovoltaic module includes the aforementioned tandem solar cells. Thus, the photovoltaic module possesses all the features and advantages of the aforementioned tandem solar cells, which will not be repeated here. Attached Figure Description

[0018] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 A schematic diagram of a tandem solar cell according to an embodiment of this application is shown; Figure 2 A schematic diagram of a tandem solar cell according to another embodiment of this application is shown; Figure 3A schematic diagram of the structure of a stacked solar cell according to yet another embodiment of this application is shown; Figure 4 A schematic diagram of the structure of a stacked solar cell according to yet another embodiment of this application is shown; Figure 5 A schematic diagram of a tandem solar cell according to yet another embodiment of this application is shown.

[0019] Explanation of reference numerals in the attached figures: 100: Crystalline silicon top cell; 200: Adaptive light conversion layer; 300: Ultraviolet light reflection layer; 310: First sublayer; 320: Second sublayer; 400: Perovskite bottom cell; 410: Perovskite absorption layer; 420: Conductive substrate; 430: First electrode; 440: First transport layer; 450: Second transport layer; 460: Passivation layer. Detailed Implementation

[0020] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0021] In one aspect of this application, a tandem solar cell is proposed. In some embodiments of this application, reference is made to... Figure 1 A tandem solar cell may include a crystalline silicon top cell 100, an adaptive light conversion layer 200, an ultraviolet light reflective layer 300, and a perovskite bottom cell 400, which are stacked sequentially.

[0022] In related technologies, perovskite solar cells are typically used as the top cell, directly receiving light for photoelectric conversion; crystalline silicon solar cells are used as the bottom cell, further utilizing light not absorbed by the perovskite. Perovskite materials are highly sensitive to ultraviolet light. When ultraviolet (UV) light irradiates the perovskite absorption layer, it triggers degradation of the perovskite material. On one hand, photocatalytic decomposition of the perovskite material leads to the breakdown of the perovskite lattice; on the other hand, it causes chemical bond breakage and ion migration, resulting in defects in the perovskite material and performance degradation. Furthermore, in related technologies, to improve the photoelectric conversion efficiency of tandem solar cells, antireflective materials such as magnesium fluoride (MgF2) and lithium fluoride (LiF) may be used to form a static conversion layer with a constant light conversion efficiency. This design only achieves optimal operation under specific light intensities. In real, variable outdoor environments, such as low light in the early morning, evening, or cloudy days, or extremely strong light at midday, its fixed efficiency often cannot efficiently utilize spectral energy, limiting the device's power generation capacity.

[0023] In this application, a crystalline silicon solar cell is used as the top cell and a perovskite solar cell as the bottom cell. The crystalline silicon top cell can preferentially resist and utilize light energy, reducing the direct impact of light on the perovskite material, thereby effectively improving the stability of the tandem solar cell. The Adaptive Optical Conversion Layer (ADCL) has intelligent dynamic response characteristics, which can adaptively adjust according to changes in the intensity of incident sunlight, ensuring that the solar cell can utilize spectral energy in a near-optimal manner at any time of day, regardless of whether it is sunny or cloudy, thereby maximizing the total power generation throughout the day. The ADCL can convert ultraviolet light into visible light that can be used by the perovskite cell, reducing the waste of ultraviolet light and improving the utilization rate of spectral energy. The ultraviolet light reflection layer can reflect the residual ultraviolet light in the incident light, preventing this part of the ultraviolet light from illuminating the perovskite absorption layer, further reducing the adverse effects of ultraviolet light on the perovskite material, thereby further improving the stability of the tandem solar cell. The perovskite bottom cell can receive processed light and perform photoelectric conversion. This design can effectively improve the stability of the tandem solar cell and extend its service life. Furthermore, it has strong environmental adaptability and can adapt to varying lighting conditions, thereby making more rational use of incident light and improving the photoelectric conversion efficiency and power generation of the tandem solar cell.

[0024] In some embodiments of this application, the adaptive light conversion layer 200 may include a first substrate and a first quantum dot, wherein the first quantum dot is dispersed in the first substrate and is doped with an activator and a sensitizer, the activator including erbium ions (Er). 3+ Thulium ions (Tm 3+ ), holmium ions (Ho) 3+ europium ions (Eu) 3+ ), terbium ions (Tb 3+ ), cerium ions (Ce) 3+ ), Dysprosium ions (Dy 3+ One or more of the following, the sensitizers include ytterbium ions (Yb). 3+ ).

[0025] These rare earth ions, due to their abundant 4f electron structure, can achieve efficient absorption and emission of light in different wavelength bands, including ultraviolet, visible, and near-infrared light. Among them, Eu... 3+ It can emit red light with a wavelength of 612nm, Tb 3+ It can emit green light with a wavelength of 545nm, Ce 3+ It can emit blue light or ultraviolet light, Dy 3+It can emit yellow-white light. The adaptive light conversion layer utilizes the nonlinear optical effect of specific rare-earth ions (activators), and its efficiency in converting ultraviolet light into visible light is not a fixed value, but can adaptively adjust according to changes in the intensity of incident sunlight. The efficiency of the adaptive light conversion layer is flexible and variable: under low light conditions, it can adjust to a higher conversion efficiency to capture more energy; under strong light conditions, it can also adjust its working state to always maintain a highly efficient conversion range.

[0026] The following details the principle behind how the adaptive light conversion layer achieves high conversion efficiency under both low and high light conditions: Upconversion and downconversion effects: Er 3+ Tm 3+ Ho 3+ Eu 3+ 、Tb 3+ Ce 3+ Dy 3+ Rare earth ions can achieve spectral conversion through "upconversion" (absorbing low-energy light and emitting high-energy light) or "downconversion" (absorbing high-energy light and emitting low-energy light). Spectral conversion mechanisms include energy transfer upconversion (ETU), excited-state absorption (ESA), cooperative sensitization upconversion (CET), and photon avalanche (PA), among which ETU and ESA are more efficient in practical applications.

[0027] Dynamic adjustment mechanism: Under low light conditions (such as early morning or cloudy days), rare earth ions have relatively improved upconversion and sensitization efficiency due to their multi-step energy accumulation characteristics, enabling them to capture more low-intensity light and efficiently convert it into visible light.

[0028] Under strong light conditions (high illuminance such as midday), the adaptive mechanism of the adaptive light conversion layer will automatically adjust according to the occupancy of the excitation energy level and the energy transfer bottleneck, avoiding unnecessary high-energy absorption, reducing non-radiative losses while maintaining high conversion efficiency, and ensuring that the device operates in the optimal efficiency range.

[0029] The following example uses erbium ions to illustrate the dynamic regulation mechanism of these rare earth ions under weak and strong light conditions: 1. Rare earth ions have abundant and narrowly spaced energy levels in their 4f electron shell (because their 4f orbitals are shielded by outer electrons, they are less affected by the crystal field and have high energy level stability). A typical example is the erbium ion (Er...). 3+ For example, its electronic energy levels include the ground state (such as...) 4 I 15 / 2 ) and multiple excited states (such as 4 F 9 / 2 , 4 S 3 / 2The energy level difference precisely matches the energy range from ultraviolet light (high energy) to visible light (medium energy) (ultraviolet photon energy ≈ 3eV-10eV, visible light ≈ 1.6eV-3eV). This energy level structure allows rare earth ions to accurately "capture" ultraviolet photons and release visible photons through energy level transitions.

[0030] 2. Under low light conditions (such as early morning or cloudy days), the intensity of incident ultraviolet light is low, and rare earth ions mainly undergo single-photon absorption-radiative transitions, which is a low-loss and highly efficient process. Absorption phase: The energy of a single ultraviolet photon is absorbed by the 4f electron of a rare-earth ion, causing the electron to transition from the ground state to a high-energy excited state (such as Er). 3+ from 4 I 15 / 2 Leap to 4 F 9 / 2 During this process, the energy of ultraviolet light is "stored" as the excitation energy of electrons. Due to the shielding effect of the 4f orbitals of rare earth ions, the energy loss (such as lattice vibration dissipation) is extremely low.

[0031] Radiation stage: Excited electrons are unstable and will rapidly relax to a lower metastable state (such as Er) through nonradiative transitions (without energy loss). 3+ from 4 F 9 / 2 Relaxation 4 S 3 / 2 Then, it transitions from the metastable state to the ground state, releasing a visible light photon (such as Er). 3+ It emits green light with a wavelength of 550nm.

[0032] Rare earth ions have a high saturation absorption threshold (meaning that strong light is required to fully excite the ground-state electrons, preventing them from absorbing more photons). Under weak light conditions, the incident light intensity is much lower than the saturation absorption threshold, ensuring a sufficient supply of ground-state electrons that can continuously absorb ultraviolet photons and transition. Therefore, the conversion efficiency does not decrease due to "electron depletion".

[0033] 3. Under strong light conditions, multiphoton absorption or energy level saturation occurs. For example, two low-energy photons are absorbed simultaneously (two-photon absorption), or high-energy electrons cannot transition in time due to the accumulation of strong light, leading to a decrease in the absorption coefficient (active downregulation of conversion efficiency). When the intensity of incident light exceeds a certain threshold, a large number of ground-state electrons of rare-earth ions are excited to high energy levels. At this time, the number of ground-state electrons is insufficient, and they cannot continue to absorb photons efficiently, exhibiting "saturation." The conversion efficiency naturally decreases, avoiding energy waste or overheating under strong light.

[0034] In some embodiments of this application, the first substrate may include one or more of silicon oxide, fluoride glass, and fluorinated polymers (e.g., PFCB, perfluorocyclobutyl aryl ether polymer). Mixing these materials with quantum dots facilitates film formation and can reduce or even prevent quantum dot aggregation.

[0035] In some embodiments of this application, the mass content of the first quantum dot can be 0.1%-10% based on the total mass of the adaptive light conversion layer. For example, the mass content of the first quantum dot can be 0.1%, 0.5%, 1%, 3%, 5%, 8%, 10%, etc. This is beneficial for further improving the light conversion and luminescence effect of the adaptive light conversion layer, thereby further increasing the power generation of the battery.

[0036] In some embodiments of this application, the thickness of the adaptive light conversion layer can be from 100 nm to 100 μm. For example, the thickness of the adaptive light conversion layer can be 100 nm, 300 nm, 500 nm, 800 nm, 1 μm, 10 μm, 50 μm, 100 μm, etc. Therefore, the adaptive light conversion layer has a suitable thickness, which can achieve dynamic adjustment without significantly increasing the overall thickness of the stacked battery, thus helping to control costs.

[0037] In some embodiments of this application, the first quantum dot may include one or more of zinc oxide quantum dots, carbon quantum dots, and perovskite quantum dots. Doping these quantum dots with an activator can yield materials with high luminous efficiency, long lifetime, and high stability.

[0038] In some embodiments of this application, the activator includes one or more of erbium ions, thulium ions, and holmium ions, and also includes one or more of europium ions, terbium ions, cerium ions, and dysprosium ions. Erbium ions, thulium ions, and holmium ions can be used as activators for efficient upconversion systems, while europium ions, terbium ions, cerium ions, and dysprosium ions can be used as activators for efficient downconversion systems. Simultaneous doping of rare-earth ions with both efficient upconversion and efficient downconversion capabilities in the first quantum dot is more conducive to the adaptive light conversion layer achieving dynamic adjustment, ensuring that the tandem solar cell operates within its optimal efficiency range, utilizing spectral energy in a near-optimal manner at any time of day, and maximizing the total power generation throughout the day.

[0039] The first quantum dot is also doped with a sensitizer, such as ytterbium ions (Yb). 3+ ), Yb 3+ In the system, it acts as a highly efficient sensitizer or energy transferor, capable of forming effective energy level coupling with the first quantum dot (e.g., zinc oxide quantum dot), maximizing the capture of energy transferred from the zinc oxide quantum dot, and then efficiently transferring the energy to the activator (e.g., Eu). 3+ ).

[0040] In some embodiments, the first quantum dot is further doped with a bridging agent, such as gadolinium ions (Gd). 3+ Gd 3 + With a unique energy level structure, it can act as an energy bridging agent to effectively suppress energy loss caused by defects in the first quantum dot (e.g., zinc oxide quantum dot). It can construct an efficient and low-loss energy transfer path with the first quantum dot, sensitizer, and activator, namely the first quantum dot → bridging agent → sensitizer → activator, thereby significantly improving the total luminescence quantum yield of the entire system.

[0041] In some embodiments, the first quantum dot may include Zn (1-a-x-y) Gd a Yb x M y O, where M is selected from one or more of erbium ions, thulium ions, holmium ions, europium ions, terbium ions, cerium ions, and dysprosium ions, and 0.005≤a≤0.05, 0.01≤x≤0.15, 0.001≤y≤0.07. For example, a can be 0.008, 0.01, 0.03, 0.05, etc., and x can be 0.01, 0.05, 0.07, 0.1, 0.12, 0.15, etc. Therefore, the first quantum dot has good luminescence performance and adaptive adjustment function, enabling the battery to utilize spectral energy in an optimized manner, which is beneficial to improving the battery's power generation.

[0042] In some embodiments, to achieve the most efficient ultraviolet downconversion and dynamic spectral management, GdO2 is used in the ZnO quantum dot matrix of the adaptive light conversion layer (ADCL). 3+ Yb 3+ Eu 3+ A scheme for co-doping with three rare earth ions.

[0043] In some specific embodiments, the activator europium ions (Eu) 3+ The number of moles of Zn² can be 1. + 1.0% of the molar number of ions. Eu 3+ It is the core "activator" that ultimately emits visible red light. A doping concentration of 1.0% is an optimized value that has been verified by numerous experiments to achieve the highest luminescence quantum efficiency in most quantum dot matrices. This concentration ensures a sufficient number of luminescent centers to absorb and convert enough light, while effectively avoiding the "concentration quenching effect" caused by excessively close inter-ion spacing.

[0044] In some specific embodiments, the sensitizer ytterbium ions (Yb 3+ The number of moles of Zn can be 2+ 8.0% of the molar number of ions. Yb 3+In this system, the high concentration of 8.0% is designed to act as a "sensitizer" or energy transfer agent, enabling it to form effective energy level coupling with the first quantum dot (ZnO quantum dot matrix). This maximizes the capture of energy transferred from the matrix and then efficiently transfers the energy to the activator Eu. 3+ The molar ratio of sensitizer to activator is 8:1, which is the ratio for achieving efficient energy transfer.

[0045] In some specific embodiments, the bridging agent gadolinium ions (Gd) 3+ The number of moles of Zn can be 2+ 2.0% of the molar number of ions. Gd 3+ With its unique energy level structure, it acts as an "energy bridging agent," effectively suppressing energy loss caused by defects in the ZnO matrix and constructing a pathway from the ZnO matrix to Gd. 3+ →Yb 3+ →Eu 3+ This provides an efficient and low-loss energy transfer path, thereby significantly improving the overall luminescent quantum yield of the entire system.

[0046] In some specific embodiments, the first substrate comprises silicon oxide, and the first quantum dot comprises Zn. 0.89 Gd 0.02 Yb 0.08 Eu 0.01 Therefore, the adaptive light conversion layer can be more dynamically adjusted to improve the overall luminescence quantum yield of the system, thereby improving the photoelectric conversion efficiency of the tandem solar cell.

[0047] In some embodiments, the first substrate comprises silicon oxide, and the first quantum dot comprises Zn. 0.89 Gd 0.02 Yb 0.08 Eu 0.01 Furthermore, based on the total mass of the adaptive light conversion layer, the mass content of the first quantum dot is 0.1%-10%.

[0048] The feasibility of a single rare earth ion initiating upconversion and downconversion functions under different conditions is one of the theoretical foundations for the dynamic adaptive function proposed in this application. Using erbium ions (Er...) as an example... 3+ For example, its specific mechanism is as follows: Upconversion mode: When the ADCL receives near-infrared light (e.g., photons with a wavelength of 980 nm) penetrating the crystalline silicon top cell, Er 3+ It will absorb two or more low-energy photons with a wavelength of 980nm in succession, causing its electrons to jump to a higher energy level, and then radiate back to the ground state, emitting green light with a wavelength of about 540nm and red light with a wavelength of about 660nm.

[0049] Down-conversion mode: When the ADCL receives high-energy ultraviolet or violet light (e.g., photons with a wavelength of 379 nm) leaked from the crystalline silicon top cell under strong light, Er 3+ Electrons are directly excited to a very high energy level, then transition to a lower excited state via non-radiative transition, and finally radiatively transition back to the ground state, emitting green light with a wavelength of approximately 540 nm and red light with a wavelength of approximately 660 nm. By utilizing Er... 3+ Due to these characteristics of rare earth ions, ADCL can spontaneously and dynamically focus on upconversion or downconversion based on the changes in photon density in different bands of the incident solar spectrum, thereby achieving intelligent energy management across the entire spectrum.

[0050] In some embodiments of this application, the adaptive light conversion layer 200 may include a second substrate, a second quantum dot, and a rare earth complex. The second quantum dot and the rare earth complex are dispersed in the second substrate. The rare earth complex includes rare earth ions and organic ligands. The rare earth ions include one or more of erbium ions, thulium ions, holmium ions, europium ions, terbium ions, cerium ions, and dysprosium ions.

[0051] Organic ligands coordinate with rare earth ions to form molecular coordination compounds. These organic ligands strongly absorb ultraviolet light energy, which they themselves cannot directly utilize. After absorbing energy, the organic ligands efficiently transfer this energy to the central rare earth ion they coordinate with via a non-radiative process within the molecule. The energized rare earth ion is then excited and releases the energy by emitting visible light, thus achieving luminescence. This process solves the problem of the weak ultraviolet light absorption capacity of rare earth ions themselves, achieving an efficient conversion from high-energy ultraviolet light to low-energy visible light.

[0052] Organic ligands can sensitize rare earth ions. After absorbing ultraviolet light, the organic ligands transfer energy to the rare earth ions without loss. The rare earth ions then emit light through multiple transitions. The energy level regulation and efficiency of this process can be automatically optimized as the incident light intensity changes.

[0053] In some embodiments of this application, the second substrate may include one or more of silicon oxide, fluoride glass, and fluorinated polymers. This facilitates film formation and can reduce or even prevent quantum dot aggregation.

[0054] In some embodiments of this application, the second quantum dot may include one or more of zinc oxide quantum dots, carbon quantum dots, and perovskite quantum dots. These quantum dots possess a certain luminescence capability, which is beneficial for improving the performance of the adaptive light conversion layer.

[0055] In some embodiments of this application, the rare earth ions include one or more of erbium ions, thulium ions, and holmium ions, and the rare earth ions include one or more of europium ions, terbium ions, cerium ions, and dysprosium ions. Therefore, the adaptive light conversion layer can better automatically adjust according to the intensity of incident sunlight, thereby improving the battery's utilization rate of incident light and photoelectric conversion efficiency.

[0056] In some embodiments of this application, the organic ligand may include one or more of β-diketones, carboxylic acids, and imidazoles. In some specific embodiments, the organic ligand may include β-diketones or carboxylic acids. In other specific embodiments, the organic ligand may include imidazoles and carboxylic acids, or it may include imidazoles and β-diketones. All of the above-mentioned organic ligands can form coordination compounds with rare earth ions. The organic ligands absorb ultraviolet light energy and transfer it to the rare earth ions, thereby exciting the rare earth ions and causing them to emit visible light.

[0057] In some embodiments of this application, reference is made to Figure 2 and Figure 3 The ultraviolet light reflecting layer 300 includes alternating layers of a first sublayer 310 and a second sublayer 320. The refractive index of the first sublayer 310 is greater than that of the second sublayer 320. The first sublayer 310 is the sublayer closest to the crystalline silicon top cell 100 in the ultraviolet light reflecting layer 300. Therefore, the ultraviolet light reflecting layer can reflect residual ultraviolet light transmitted through the crystalline silicon top cell and the adaptive light conversion layer, reducing the amount of ultraviolet light reaching the perovskite absorption layer, thereby further improving the stability of the perovskite absorption layer.

[0058] In some specific embodiments, reference is made to Figure 2 The ultraviolet light reflecting layer 300 may consist of a first sublayer 310 and a second sublayer 320, with the first sublayer 310 located between the adaptive light conversion layer 200 and the second sublayer 320. In other specific embodiments, refer to... Figure 3 The ultraviolet light reflecting layer 300 may consist of two first sub-layers 310 and one second sub-layer 320, with the second sub-layer 320 located between the two first sub-layers 310. In some embodiments, the ultraviolet light reflecting layer 300 may include multiple first sub-layers 310 and multiple second sub-layers 320. The specific number is not particularly limited in this application, as long as the ultraviolet light reflecting layer can effectively reflect ultraviolet light.

[0059] In some embodiments of this application, the first sublayer 310 may include one or more of titanium oxide, hafnium oxide, and tantalum oxide. In some embodiments of this application, the second sublayer 320 may include silicon oxide. The first sublayer has a high reflectivity, and the second sublayer has a low reflectivity. The stacked arrangement can form a distributed Bragg reflector (DBR), which can reflect ultraviolet light and reduce the damage of ultraviolet light to the perovskite absorption layer.

[0060] In some embodiments of this application, the crystalline silicon top cell 100 can be a Topcon (Tunnel Oxide Passivated Contact) solar cell or an HJT (Heterojunction) solar cell, or a back-contact IBC, TBC, HBC, or hybrid THBC cell; this application does not limit the specific type of cell. The aforementioned cell can utilize a portion of the incident light, and can allow a portion of the incident light to pass through and illuminate the perovskite bottom cell below.

[0061] In some embodiments of this application, the crystalline silicon top cell 100 can be a Topcon solar cell, which includes a crystalline silicon substrate, a tunneling oxide layer (e.g., a silicon oxide layer) located on one side of the crystalline silicon substrate, an N-type polycrystalline silicon layer and a first grid line (or transparent conductive electrode) in contact with the N-type polycrystalline silicon, and a P-type doped silicon layer located on the other side of the crystalline silicon substrate and a second grid line in contact with the P-type doped silicon layer. In some embodiments, an aluminum oxide passivation layer and an antireflection layer may also be disposed on the side of the N-type polycrystalline silicon layer away from the crystalline silicon substrate, and an aluminum oxide passivation layer and an antireflection layer may also be disposed on the side of the P-type doped silicon layer away from the crystalline silicon substrate.

[0062] In some other embodiments of this application, the crystalline silicon top cell 100 can be an HJT solar cell, which includes a crystalline silicon substrate, an intrinsic amorphous silicon layer, an N-type amorphous silicon layer and grid lines (or transparent conductive electrodes) located on one side of the crystalline silicon substrate, and an intrinsic amorphous silicon layer, a P-type amorphous silicon layer and grid lines located on the other side of the crystalline silicon substrate.

[0063] In some embodiments of this application, reference is made to Figure 4 The perovskite bottom cell 400 may include a perovskite absorber layer 410, a conductive substrate 420, a first electrode 430, a first transport layer 440, and a second transport layer 450. The conductive substrate 420 may include a substrate (e.g., a glass substrate or a flexible substrate) and a transparent conductive oxide electrode (e.g., ITO, FTO, IZO, etc.) located on the substrate. One of the first transport layer 440 and the second transport layer 450 is a hole transport layer, and the other is an electron transport layer.

[0064] In some embodiments, the perovskite absorber layer 410 can be made of ABX3, wherein A is a monovalent cation, including but not limited to one or a mixture of monovalent cations selected from cesium (Cs), rubidium (Rb), methylamino (CH3NH3), and formamidinyl (CH2(NH2)2); B is a divalent cation, including but not limited to one or a mixture of divalent cations selected from lead (Pb) and tin (Sn); and X is a monovalent anion, including but not limited to one or a mixture of monovalent anions selected from iodine (I), bromine (Br), chloride (Cl), fluorine (F), and thiocyanate (SCN). In some specific embodiments, the perovskite absorber layer 410 can be made of Cs. x FA 1- x Pb(I y Br 1-y 3, x and y are 0 and 1 respectively.

[0065] In some specific embodiments, the material of the perovskite absorber layer 410 can be Cs. 0.22 FA 0.78 Pb(I 0.85 Br 0.15 3.

[0066] In some embodiments, the material of the hole transport layer may include nickel oxide (NiO). x ,1≤x≤2), cuprous iodide (CuI), cuprous oxide (Cu2O), cuprous thiocyanate (CuSCN), 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene (Spiro-OMeTAD), 2,2',7,7'-tetrakis(di-p-tolylamino)spiro-9,9'-difluorene (Spiro TTB), poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), and [4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphonic acid (MeO-4PACz), (4-(3,6-dimethyl-9H-carbazole-9-yl)butyl)phosphonic acid (Me-4PACz), [4-(9H-carbazole-9-yl)butyl]phosphonic acid (4PACz), (4-(3,6-dibromo- ... It is one or more of the following: (2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl)phosphonic acid (Br-4PACz), (2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl)phosphonic acid (MeO-2PACz), (2-(9H-carbazole-9-yl)ethyl)phosphonic acid (2PACz), and (2-(3,6-dibromo-9H-carbazole-9-yl)ethyl)phosphonic acid (Br-2PACz).

[0067] In some embodiments, the material of the electron transport layer may include, but is not limited to, tin oxide, fullerenes and their derivatives, imide compounds, quinone compounds, etc. Exemplarily, the imide compounds include one or more of phthalimide, succinimide, N-bromosuccinimide, glutarimide, or maleimide; exemplarily, the quinone compounds include one or more of benzoquinone, naphthoquinone, phenanthrenequinone, or anthraquinone; exemplarily, the fullerenes and their derivatives include fullerene C 60 Fullerene C 70 PCBM([6,6]-phenyl-C 61 methyl butyrate), [6,6]-phenyl C 71 Methyl butyrate (PC) 71 At least one of (BM). Further, the electron transport layer can be a single-layer structure, or a double-layer or triple-layer structure. In some specific embodiments, the electron transport layer can be a C layer with a thickness of 5-20 nm. 60 A layer of tin oxide with a thickness of 15-20 nm is added. The tin oxide layer can protect C in subsequent processes. 60 .

[0068] In some embodiments, the first electrode 430 may be a transparent conductive electrode, for example, the first electrode may be a transparent conductive oxide electrode (e.g., ITO, FTO, IZO, etc.).

[0069] In other embodiments, reference is made to... Figure 5 The perovskite bottom solar cell 400 may further include a passivation layer 460, for example, a PVP (polyvinylpyrrolidone) passivation layer, which may be disposed between the perovskite absorber layer 410 and the second transport layer 450. This passivation layer can passivate defects in the perovskite absorber layer, reduce non-radiative recombination, and provide a certain degree of water and oxygen barrier, thereby further improving the stability of the perovskite bottom solar cell.

[0070] In some embodiments, the passivation layer (PVP passivation layer) of the perovskite solar cell can also be disposed between the perovskite absorber layer and the first transport layer, serving as a back passivation layer, which can effectively passivate the surface defects of the perovskite absorber layer and reduce non-radiative recombination.

[0071] In some embodiments of this application, the tandem solar cell further includes a bottom cell encapsulation layer, which can block water and oxygen to a certain extent and scatter ultraviolet light, thereby further improving the stability of the perovskite bottom cell and extending its service life.

[0072] In some embodiments of this application, the bottom cell encapsulation layer includes a Parylene-C sublayer, an alumina sublayer, and a silicon oxide sublayer stacked sequentially. The silicon oxide sublayer is located on the side of the alumina sublayer closest to the perovskite bottom cell 400; that is, the alumina sublayer is disposed between the Parylene-C sublayer and the silicon oxide sublayer, and the silicon oxide sublayer is disposed between the alumina sublayer and the perovskite bottom cell 400. Therefore, the encapsulation layer can effectively block water and oxygen and scatter ultraviolet light, thereby effectively improving the stability of the perovskite bottom cell and extending its service life.

[0073] In some embodiments of this application, the tandem solar cell can be a four-terminal structure cell. Thus, both the top and bottom cells have upper and lower electrodes, and the top and bottom cells are independent of each other, with current matching constraints, allowing for independent optimization. This facilitates performance maximization, offers flexible manufacturing processes, high fault tolerance, and greater industrialization potential.

[0074] In summary, this application uses a crystalline silicon solar cell as the top cell and a perovskite solar cell as the bottom cell. The crystalline silicon cell can preferentially resist and utilize light, playing a preliminary role in photoelectric conversion and protection, reducing the direct impact of light on the relatively fragile perovskite material, effectively improving the stability of the tandem solar cell and extending its service life. The adaptive light conversion layer can dynamically adapt to different light intensities, adjusting and converting light to maintain a relatively high photoelectric conversion efficiency. The ultraviolet light reflective layer can reflect residual ultraviolet light, further reducing the damage of ultraviolet light to the perovskite absorption layer, thereby further improving the stability of the tandem solar cell. Furthermore, the encapsulation structure composed of multiple film layers can block water and oxygen and scatter ultraviolet light, which is more conducive to improving the stability of the tandem solar cell.

[0075] In another aspect of this application, a photovoltaic module is proposed, including the aforementioned tandem solar cells.

[0076] In some embodiments of this application, the photovoltaic module may include one or more tandem solar cells.

[0077] The present application will be described below through specific embodiments. Those skilled in the art will understand that the specific embodiments below are merely illustrative and do not limit the scope of the present application in any way. Furthermore, in the following embodiments, unless otherwise specified, the materials and equipment used are commercially available. If specific processing conditions and methods are not explicitly described in the later embodiments, conditions and methods known in the art can be used for processing.

[0078] Example 1 The stacked device in Example 1 is a four-terminal stacked battery, which, from the direction of light incidence (from top to bottom), comprises: Top Cell: An optimized semi-transparent n-type tunneling oxide passivated contact (TOPCon) crystalline silicon solar cell. This TOPCon crystalline silicon cell includes a crystalline silicon substrate, a tunneling oxide layer (silicon oxide layer) on one side of the crystalline silicon substrate (light-emitting side), an N-type polycrystalline silicon layer, and gate lines contacting the N-type polycrystalline silicon layer; and a P-type doped silicon layer (as the emitter) on the other side of the crystalline silicon substrate (light-incident side) and gate lines contacting the P-type doped silicon layer. The cell is optimized to maximize the utilization of the visible and near-infrared spectra while allowing long-wave infrared light and residual ultraviolet light to pass through. The top cell first absorbs and converts a portion of the solar spectrum, while simultaneously acting as the first physical barrier, filtering out some high-energy ultraviolet light.

[0079] Adaptive Optical Conversion Layer (ADCL): This layer contains Gd for dynamic spectral conversion. 3+ / Yb 3+ / Eu 3+ Rare earth ion-doped ZnO quantum dots, specifically Zn 0.89 Gd 0.02 Yb 0.08 Eu 0.01 O-quantum dots are quantum dots dispersed in a silicon oxide matrix. They can efficiently convert harmful ultraviolet light that penetrates the top cell into visible light that can be used in the underlying layer, and can adaptively adjust the conversion efficiency according to the light intensity.

[0080] Ultraviolet reflective coating: A distributed Bragg reflector (DBR) composed of alternating layers of TiO2 / SiO2, with the TiO2 sublayer closest to the top cell. This layer can reflect residual ultraviolet light, reducing damage to the perovskite absorption layer caused by ultraviolet light.

[0081] Bottom Cell: A cesium formamidinium perovskite solar cell using physical vapor deposition (PVD) passivation technology to absorb spectral energy optimized by the ADCL layer. The specific characteristics of this bottom cell are as follows: Perovskite absorber layer material: A perovskite composed of cesium formamidinium (Cs / FA) mixed cations and iodine bromide (I / Br) mixed halides. Specifically, the material composition of its perovskite absorber layer is Cs... 0.22 FA 0.78 Pb(I 0.85 Br 0.15 3. The bottom cell, from bottom to top, includes: FTO conductive glass, electron transport layer, perovskite absorber layer, PVP passivation layer, hole transport layer, and transparent conductive electrode. The PVP passivation layer is prepared by physical vapor deposition (PVD) and is used to effectively passivate surface defects of the perovskite absorber layer and reduce non-radiative recombination.

[0082] The high-barrier encapsulation layer is a multilayer composite film composed of Parylene-C polymer, alumina (Al2O3), and silicon dioxide (SiO2). The alumina sublayer is located between the Parylene-C sublayer and the silicon dioxide sublayer, and the silicon dioxide sublayer is located between the alumina sublayer and the perovskite bottom cell, providing water and oxygen barrier properties for the entire device.

[0083] Example 2 The stacked device structure in Example 2 is basically the same as that in Example 1, the main difference being the type of top cell.

[0084] The top cell in Example 2 is an optimized semi-transparent heterojunction (HJT) crystalline silicon cell. The specific structure of the top cell is as follows: The HJT top cell includes a crystalline silicon substrate, an intrinsic amorphous silicon layer, a P-type amorphous silicon layer, and gate lines located on one side of the crystalline silicon substrate (light incident side); and an intrinsic amorphous silicon layer, an N-type amorphous silicon layer, and gate lines located on the other side of the crystalline silicon substrate (light emitting side). The HJT top cell can be fabricated using low-temperature processes and has a high open-circuit voltage; it is also optimized to achieve efficient semi-transparent performance.

[0085] The adaptive light conversion layer, ultraviolet light reflection coating, bottom battery, and high barrier encapsulation layer in Example 2 are the same as those in Example 1.

[0086] Comparative Example 1 A conventional four-terminal (4T) upright perovskite / crystalline silicon tandem solar cell was used as a comparative example. The structure of the tandem solar cell in this comparative example is as follows: Top cell (semi-transparent perovskite cell): Employs a conventional "positive" nip structure. On an FTO conductive glass substrate, a SnO2 (tin dioxide) electron transport layer and a Cs layer are sequentially deposited. 0.22 FA 0.78 Pb(I 0.85 Br 0.15 The structure consists of a perovskite absorber layer, an inorganic NiOx (nickel oxide) hole transport layer, and finally, a transparent conductive electrode to draw out the current.

[0087] The bottom cell (crystalline silicon cell): an n-type TOPCon cell optimized for efficient absorption of the near-infrared spectrum. The bottom cell includes: a P-type doped silicon layer (as the emitter) and gate lines located on one side of the crystalline silicon substrate (the light incident side); a tunneling oxide layer (silicon oxide layer), an N-type polycrystalline silicon layer, and gate lines in contact with the N-type polycrystalline silicon layer located on the other side of the crystalline silicon substrate (the back side) (this constitutes the TOPCon passivation contact structure).

[0088] Encapsulation: Encapsulation is performed using a multilayer composite film composed of Parylene-C polymer, alumina (Al2O3), and silicon dioxide (SiO2).

[0089] Although Comparative Example 1 uses a relatively stable inorganic NiOx hole transport layer, its "orthogonal" structure exposes the fragile perovskite absorber layer directly to ultraviolet radiation, resulting in inherent defects in its long-term stability.

[0090] All key performance indicators mentioned in this application were tested in accordance with internationally recognized industry standards. The test results are recorded in Table 1, and the specific test methods are as follows: Photoelectric conversion efficiency (PCE): According to IEC 60904-1 standard, under standard test conditions (STC: spectrum AM1.5G, illuminance 1000W / m²), 2 Accurate measurements were taken using an AAA-grade solar simulator at a battery temperature of 25°C.

[0091] Long-term stability (T) 80 The long-term stability of the device is evaluated according to the damp heat aging test in IEC 61215-2:2021. The device is placed in a harsh environment of 85°C and 85% relative humidity, continuously illuminated, and its maximum power point (MPPT) is tracked. The time it takes for its efficiency to decay to 80% of its initial value is recorded.

[0092] Water vapor transmission rate (WVTR): Tested according to ISO 15106-3 standard using a professional MOCON electrostatic water vapor permeation apparatus at 38°C and 90% relative humidity to evaluate the sealing barrier performance of the encapsulation layer.

[0093] Table 1

[0094] It should be noted that the photoelectric conversion efficiency of the tandem cells in Examples 1-2 and Comparative Example 1 were obtained by testing 100 samples.

[0095] In the description of this application, the terms "upper" and "lower" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and do not require this application to be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this application.

[0096] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," and "other embodiments" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment is included in at least one embodiment of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples, without contradiction. Additionally, it should be noted that in this specification, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features.

[0097] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A tandem solar cell, characterized in that, It includes a crystalline silicon top cell, an adaptive light conversion layer, an ultraviolet light reflection layer, and a perovskite bottom cell, which are stacked in sequence.

2. The tandem solar cell according to claim 1, characterized in that, The adaptive light conversion layer includes a first substrate and a first quantum dot. The first quantum dot is dispersed in the first substrate and is doped with an activator and a sensitizer. The activator includes one or more of erbium ions, thulium ions, holmium ions, europium ions, terbium ions, cerium ions, and dysprosium ions. The sensitizer includes ytterbium ions.

3. The tandem solar cell according to claim 2, characterized in that, The adaptive light conversion layer satisfies at least one of the following conditions: The first substrate includes one or more of silicon oxide, fluoride glass, and fluorinated polymers; The first quantum dot includes one or more of zinc oxide quantum dots, carbon quantum dots, and perovskite quantum dots; The activator includes one or more of erbium ions, thulium ions, and holmium ions, and the activator also includes one or more of europium ions, terbium ions, cerium ions, and dysprosium ions; The first quantum dot is also doped with a bridging agent, optionally including gadolinium ions; Based on the total mass of the adaptive light conversion layer, the mass content of the first quantum dot is 0.1%-10%.

4. The tandem solar cell according to claim 2, characterized in that, The first quantum dot includes Zn (1-a-x-y) Gd a Yb x M y O, where M is selected from one or more of erbium ion, thulium ion, holmium ion, europium ion, terbium ion, cerium ion, and dysprosium ion, 0.005≤a≤0.05, 0.01≤x≤0.15, and 0.001≤y≤0.

07.

5. The tandem solar cell according to claim 1, characterized in that, The adaptive light conversion layer includes a second substrate, a second quantum dot, and a rare earth complex. The second quantum dot and the rare earth complex are dispersed in the second substrate. The rare earth complex includes rare earth ions and organic ligands. The rare earth ions include one or more of erbium ions, thulium ions, holmium ions, europium ions, terbium ions, cerium ions, and dysprosium ions.

6. The tandem solar cell according to claim 5, characterized in that, The adaptive light conversion layer satisfies at least one of the following conditions: The second matrix includes one or more of silicon oxide, fluoride glass, and fluorinated polymers; The second quantum dot includes one or more of zinc oxide quantum dots, carbon quantum dots, and perovskite quantum dots; The rare earth ions include one or more of erbium ions, thulium ions, and holmium ions, and the rare earth ions include one or more of europium ions, terbium ions, cerium ions, and dysprosium ions; The organic ligands include one or more of β-diketones, carboxylic acids, and imidazoles.

7. The tandem solar cell according to any one of claims 1-6, characterized in that, The thickness of the adaptive light conversion layer is 100nm-100μm.

8. The tandem solar cell according to any one of claims 1-6, characterized in that, The ultraviolet light reflective layer includes an alternately stacked first sub-layer and a second sub-layer, wherein the refractive index of the first sub-layer is greater than the refractive index of the second sub-layer, and the sub-layer of the ultraviolet light reflective layer that is closest to the crystalline silicon top cell is the first sub-layer. Optionally, the first sublayer comprises one or more of titanium oxide, hafnium oxide, and tantalum oxide; Optionally, the second sublayer comprises silicon oxide.

9. The tandem solar cell according to any one of claims 1-6, characterized in that, The stacked solar cell is a four-terminal structure cell; And / or, the stacked solar cell further includes a bottom cell encapsulation layer; Optionally, the bottom cell encapsulation layer includes a Perylene C sublayer, an alumina sublayer, and a silicon oxide sublayer stacked sequentially, with the silicon oxide sublayer located on the side of the alumina sublayer closer to the perovskite bottom cell.

10. A photovoltaic module, characterized in that, The tandem solar cell includes any one of claims 1-9.

Images