A stacked solar cell with spectral complementary synergy performance
By using a stacked structure of crystalline silicon cells, medium-bandgap perovskite cells, and wide-bandgap perovskite cells, complementary and synergistic operation of spectra is achieved, solving the problems of insufficient spectral coverage and stability of stacked solar cells, improving photoelectric conversion efficiency and stability, and reducing costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- ZHEJIANG NENGFENG PHOTOELECTRIC TECH CO LTD
- Filing Date
- 2025-07-17
- Publication Date
- 2026-06-09
AI Technical Summary
Existing tandem solar cells have shortcomings in terms of spectral coverage and material stability, making it difficult to achieve efficient utilization of solar energy. They also suffer from structural damage and performance degradation due to interlayer stress and environmental factors.
It adopts a stacked structure of crystalline silicon cells, medium bandgap perovskite cells and wide bandgap perovskite cells, and achieves spectral complementarity and synergistic operation through six-terminal connection. Each layer works independently and optimizes current output, and the stability is improved by combining an insulating and light-transmitting layer.
It significantly improves photoelectric conversion efficiency to over 32%, enhances battery stability, and reduces costs, making it suitable for large-scale commercial applications.
Smart Images
Figure CN224343710U_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of solar cell technology, specifically to a tandem solar cell with spectral complementary synergistic performance. Background Technology
[0002] Solar energy, as a clean, sustainable, and abundant energy source, plays a crucial role in the global energy structure's transition towards a low-carbon and environmentally friendly model. With the continuous growth of global energy demand and increasing environmental awareness, the efficient utilization of solar energy has become a core pursuit in scientific research and industry. As a key device for directly converting solar energy into electricity, the improvement of solar cell performance plays a decisive role in promoting the widespread application of solar energy.
[0003] In the development of solar cells, traditional single-junction solar cells have long dominated. These cells are built based on a single semiconductor material and are limited by the inherent band gap of the material itself. Taking the widely used monocrystalline silicon solar cell as an example, its theoretical efficiency limit is about 29.4%, a bottleneck determined by the Shockley-Quisser limit in semiconductor physics. In actual production and application scenarios, the efficiency of monocrystalline silicon solar cells mostly hovers in the range of 20%-25%. This is because single-junction cells can only absorb photons within a specific energy range. When the photon energy is lower than the material's band gap, electron-hole pairs cannot be excited, resulting in energy waste; while when the photon energy is higher than the band gap, the excess energy is dissipated as heat, which also reduces the energy conversion efficiency.
[0004] To overcome the efficiency limitations of single-junction solar cells, tandem solar cells were developed. The design concept of tandem cells is to stack semiconductor materials with different bandgap sizes in a specific order, allowing each layer to absorb sunlight across different wavelengths, thus achieving a more comprehensive utilization of the solar spectrum. Common tandem structures include double-junction and triple-junction structures. Double-junction tandem cells generally combine two materials with different bandgap sizes, and compared to single-junction cells, they improve photoelectric conversion efficiency to a certain extent.
[0005] The shortcomings of existing technologies: Existing double-junction structures still struggle to fully cover the entire solar spectrum, resulting in insufficient utilization of light in some intermediate wavelength ranges. While triple-junction tandem solar cells further increase spectral coverage, practical applications present more complex challenges in lattice matching, band alignment, and carrier transport between different material layers. In terms of stability, existing tandem solar cells also face numerous challenges. Firstly, the different thermal expansion coefficients of the material layers vary. During actual use, stress can easily accumulate between layers with temperature changes, potentially leading to structural damage and affecting battery lifespan. Secondly, some materials undergo degradation reactions under environmental factors such as light and humidity. For example, some organic materials experience molecular structural changes under prolonged light exposure, leading to a gradual decline in battery performance. For instance, a utility model patent application with application number 201510979043.3 mentions a mechanically tandem perovskite solar cell and its fabrication method. Its main shortcomings are: limited layer count and material homogeneity: relying solely on perovskite double-layer stacking without incorporating crystalline silicon to extend the spectrum; large band gap with a lack of transition layers, resulting in inconsistent current output. Utility Model Content
[0006] The purpose of this invention is to address the aforementioned problems in existing technologies by proposing a tandem solar cell with spectral complementary synergistic performance.
[0007] The purpose of this utility model can be achieved through the following technical solution: a tandem solar cell with spectral complementary synergistic performance, which is provided from bottom to top as a bottom layer, an insulating and light-transmitting layer one, an intermediate layer, an insulating and light-transmitting layer two, and a top layer. The bottom layer is a crystalline silicon cell, the intermediate layer is a medium bandgap perovskite cell, and the top layer is a wide bandgap perovskite cell.
[0008] Crystalline silicon solar cells use monocrystalline or polycrystalline silicon materials, which, due to their high carrier mobility and good stability, primarily absorb long-wavelength sunlight. Their bandgap ranges from 1.1 to 1.2 eV. Mid-bandgap perovskite solar cells use organic-inorganic hybrid perovskite materials, achieving mid-bandgap characteristics by adjusting the material composition, with a bandgap range of 1.2 to 1.4 eV. They primarily absorb medium- to long-wavelength sunlight. Wide-bandgap perovskite solar cells also use organic-inorganic hybrid perovskite materials, achieving a wide bandgap range of 1.6 to 1.8 eV through strategies such as adjusting the material composition and adding additives, exhibiting strong absorption capabilities for short-wavelength sunlight.
[0009] Positive terminals T1 and negative terminals T2 are drawn from the positive and negative electrode layers of a crystalline silicon solar cell, respectively; positive terminals T3 and negative terminals T4 are drawn from the positive and negative electrode layers of a mid-bandgap perovskite solar cell, respectively; and positive terminals T5 and negative terminals T6 are drawn from the positive and negative electrode layers of a wide-bandgap perovskite solar cell, respectively.
[0010] This six-terminal structure allows each battery layer to work independently, and through flexible connection and precise control via external circuitry, it fully leverages the advantages of each layer.
[0011] Spectral complementarity and synergistic operation: When sunlight shines on the tandem solar cell, the wide-bandgap perovskite cell first absorbs short-wavelength light, converting high-energy photons into electrical energy; the remaining medium- and long-wavelength light passes through this layer to reach the medium-bandgap perovskite cell layer, where it absorbs the medium- and long-wavelength light and generates electrical energy; finally, the long-wavelength light reaches the crystalline silicon cell layer, where it converts it into electrical energy. This spectral complementarity allows the tandem solar cell to make more efficient use of solar energy, improving the overall photoelectric conversion efficiency. The six-terminal structure allows for optimized adjustment of the current generated by each cell layer according to actual conditions, further enhancing cell performance.
[0012] Preferably, the band gap range of the crystalline silicon cell is 1.1-1.2 eV, which can effectively absorb light with a wavelength of 700-1100 nm.
[0013] Preferably, the band gap of the medium band gap perovskite solar cell is 1.2-1.4 eV, and this layer mainly absorbs medium and long wavelength sunlight, corresponding to a wavelength range of 500-700 nm.
[0014] Preferably, the wide bandgap perovskite solar cell has a bandgap range of 1.6-1.8 eV, strong absorption capability for short-wavelength sunlight, and an absorption wavelength range of 300-500 nm.
[0015] Preferably, the insulating and light-transmitting layer is a silicon dioxide film or a polyethylene terephthalate film.
[0016] Preferably, the insulating light-transmitting layer two is a silicon dioxide film or a polyethylene terephthalate film.
[0017] Compared with the prior art, the present invention has the following beneficial effects:
[0018] 1. Significantly Improved Photovoltaic Conversion Efficiency: By leveraging the complementary spectral characteristics of wide-bandgap perovskite, medium-bandgap perovskite, and crystalline silicon cells, tandem solar cells can more fully utilize solar energy, theoretically breaking through the efficiency limit of single-junction solar cells. Experimental tests show that the photovoltaic conversion efficiency of this tandem solar cell can reach over 32%, a significant improvement compared to traditional single-junction solar cells.
[0019] 2. Enhanced Battery Stability: The stacked structure of the three battery layers ensures good performance under various lighting conditions. The high stability of the crystalline silicon battery lays the foundation for the entire stacked battery, while the mid-bandgap and wide-bandgap perovskite batteries improve the utilization efficiency of different wavelengths of light without affecting stability. The six-terminal structure allows each battery layer to operate independently; when one layer is affected by external factors, the other layers can still operate normally, enhancing the overall stability and reliability of the battery.
[0020] 3. Cost Advantage: The fabrication process is relatively simple, and the material cost is low. Compared with traditional multi-junction solar cells, the wide-bandgap perovskite / medium-bandgap perovskite / crystalline silicon six-terminal tandem solar cell of this invention has a certain cost advantage while ensuring high efficiency, which is conducive to large-scale commercial application. Attached Figure Description
[0021] Figure 1 This is a structural diagram of a tandem solar cell.
[0022] Figure 2 This is the spectral absorption diagram of a tandem solar cell.
[0023] 1. Crystalline silicon solar cell; 2. Insulating and light-transmitting layer one; 3. Medium bandgap perovskite solar cell; 4. Insulating and light-transmitting layer two; 5. Wide bandgap perovskite solar cell. Detailed Implementation
[0024] The following are specific embodiments of the present invention, which further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.
[0025] Example 1
[0026] like Figure 1 As shown, a tandem solar cell with spectral complementary synergistic performance is provided. The tandem solar cell has, from bottom to top, a bottom layer, an insulating and transparent layer 1, a middle layer, an insulating and transparent layer 2, and a top layer. The bottom layer is a crystalline silicon cell 1, the middle layer is a medium bandgap perovskite cell 3, and the top layer is a wide bandgap perovskite cell 5. Positive terminals T1 and T2 are drawn from the positive and negative electrode layers of the crystalline silicon cell 1, respectively; positive terminals T3 and T4 are drawn from the positive and negative electrode layers of the medium bandgap perovskite cell 3, respectively; and positive terminals T5 and T6 are drawn from the positive and negative electrode layers of the wide bandgap perovskite cell 5, respectively.
[0027] Preferably, the bandgap range of the crystalline silicon cell 1 is 1.1-1.2 eV, which can effectively absorb light with a wavelength of 700-1100 nm.
[0028] Preferably, the bandgap range of the medium bandgap perovskite solar cell 3 is 1.2-1.4 eV. This layer mainly absorbs medium and long wavelength sunlight, corresponding to a wavelength range of 500-700 nm.
[0029] Preferably, the wide bandgap perovskite solar cell 5 has a bandgap range of 1.6-1.8 eV, strong absorption capability for short-wavelength sunlight, and an absorption wavelength range of 300-500 nm.
[0030] Preferably, the insulating and light-transmitting layer 2 is a silicon dioxide film or a polyethylene terephthalate film.
[0031] Preferably, the insulating light-transmitting layer two is a silicon dioxide film or a polyethylene terephthalate film.
[0032] Example 2
[0033] A method for fabricating a tandem solar cell with spectral complementary synergistic properties, used to fabricate the tandem solar cell in Example 1, includes the following steps:
[0034] S1 Preparation of medium bandgap perovskite solar cell 3: Transparent conductive negative electrode layer: Indium tin oxide (ITO) glass was selected as the substrate and ultrasonically cleaned for 20 minutes in sequence with detergent, deionized water, acetone and ethanol to ensure the substrate surface was clean, and used as the negative layer;
[0035] Electron transport layer deposition: Zinc oxide (ZnO) was selected as the electron transport layer material and prepared using the sol-gel method. Using ethanolamine (EA) and zinc acetate as precursors, a ZnO thin film was deposited on the surface of ITO glass using a spin-coating process, followed by annealing at 150℃, with the thickness controlled at 30-50 nm.
[0036] Preparation of mid-bandgap perovskite layer: The mid-bandgap perovskite component (Cs) in the mixed halide is... 0.05 MA 0.1 FA 0.85 PbI3 was dissolved in a mixed solvent of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) to prepare a solution with a concentration of 1.5–2.0 mol / L. First, the solution was spin-coated at a low speed of 800–1500 rpm for 10–15 seconds to ensure uniform distribution on the ZnO substrate. Then, it was spin-coated at a high speed of 3500–5000 rpm for 15–25 seconds to form a uniform mid-bandgap perovskite film. Finally, the anti-solvent chlorobenzene was added dropwise over 15 seconds. During spin-coating, the ambient humidity must be strictly controlled below 35% to prevent precursor hydrolysis. Finally, the film was annealed at 100°C for 30 minutes to form a perovskite film of approximately 500 nm.
[0037] Hole transport layer preparation: Material selection and solution preparation: Poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA) was selected as the hole transport material and dissolved in toluene to prepare a solution with a concentration of 30-50 mg / mL. Spin-coating process: The prepared hole transport layer solution was dropped onto a mid-bandgap perovskite film and spin-coated at 2500-3500 rpm for 25-35 seconds to form a uniform hole transport layer film. After spin-coating, the sample was annealed at 90-110℃ for 8-12 minutes to form a 10-20 nm hole transport layer.
[0038] Positive electrode deposition: Metal electrode evaporation: A silver metal electrode is deposited on the hole transport layer using PVD technology, serving as the positive electrode layer for the mid-bandgap perovskite solar cell 3. The process is carried out under high vacuum conditions, with the vacuum level maintained. By controlling the evaporation time and rate, the thickness of the positive electrode layer can be controlled to 10-20 nm.
[0039] S2 Wide Bandgap Perovskite Layer Preparation: Transparent Negative Electrode Selection: Indium Tin Oxide (ITO) glass was selected as the substrate and ultrasonically cleaned for 20 minutes in sequence with detergent, deionized water, acetone and ethanol to ensure the substrate surface was clean, thus serving as the negative electrode layer;
[0040] Electron transport layer deposition: Titanium dioxide (TiO2) was selected. The electron transport layer was prepared using the sol-gel method. Electron transport layer. Tetrabutyl titanate ( Anhydrous ethanol, glacial acetic acid, and deionized water are mixed in a specific ratio and deposited on the ITO surface using a spin-coating process. For thin film deposition, the spin coating speed is controlled at 2000-4000 rpm. After deposition, the glass is annealed at 450-550℃ for 30-60 minutes.
[0041] Preparation of wide bandgap perovskite layer: FAPbI3 was dissolved in a mixed solvent of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) to prepare a solution with a concentration of 1.5–2.0 mol / L. Increasing the PbBr2 content and simultaneously adding MACl as an additive (10–20 mol%) synergistically improved the short-circuit current density of the mid-bandgap perovskite solar cell 3. First, the solution was uniformly spread on the substrate by spin-coating at a low speed of 1000–2000 rpm for 5–10 seconds, followed by high-speed spin-coating at 4000–6000 rpm for 20–30 seconds to form a uniform wide bandgap perovskite film. Ethyl acetate was added dropwise as an antisolvent at the 10th second. After spin-coating, the film was annealed at 100°C for 30 minutes to form a perovskite layer of approximately 400–600 nm.
[0042] Hole transport layer preparation: 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene (Spiro-OMeTAD) was selected as the hole transport material and dissolved in chlorobenzene to prepare a solution with a concentration of 70-90 mg / mL. Simultaneously, lithium bis(trifluoromethane)sulfonylimide (Li-TFSI) and 4-tert-butylpyridine (t-BP) additives were added to the solution to improve hole transport performance. The concentration of Li-TFSI was 18-22 mg / mL, and the concentration of t-BP was 28-32 μL / mL. The sample was spin-coated at 3000-4000 rpm for 30-40 seconds to form a uniform hole transport layer film. After spin-coating, the sample was annealed at 80-100℃ for 10-15 minutes to determine the desired hole transport layer thickness.
[0043] Positive electrode deposition: Metal electrode evaporation: ITO metal is deposited on the hole transport layer using PVD technology to serve as the positive electrode of the mid-bandgap perovskite solar cell 3. The process is carried out under high vacuum, with the vacuum level maintained at [value missing]. By controlling the evaporation time and rate, the thickness of the positive electrode layer can be controlled within the range of 80-120 nm.
[0044] S3 Insulating and Transparent Layer Preparation and Assembly: After preparing insulating and transparent layer 12 on the positive electrode layer of the medium bandgap perovskite solar cell 3 using PVD technology, insulating and transparent layer 12 is bonded to the crystalline silicon solar cell 1; after preparing insulating and transparent layer 24 on the positive electrode layer of the wide bandgap perovskite solar cell 5 using PVD technology, insulating and transparent layer 24 is bonded to the medium bandgap perovskite solar cell 3.
[0045] Performance testing: The prepared tandem solar cells were subjected to performance testing, and the results are as follows: Figure 2 As shown.
[0046] The specific embodiments described herein are merely illustrative examples illustrating the spirit of this utility model. Those skilled in the art to which this utility model pertains may make various modifications or additions to the described specific embodiments or use similar methods to replace them, without departing from the spirit of this utility model or exceeding the defined scope.
Claims
1. A tandem solar cell with spectral complementary synergistic properties, characterized in that, The structure consists of a bottom layer, an insulating and transparent layer 1, a middle layer, an insulating and transparent layer 2, and a top layer, arranged sequentially from bottom to top. The bottom layer is a crystalline silicon cell, the middle layer is a medium bandgap perovskite cell, and the top layer is a wide bandgap perovskite cell. Positive terminals T1 and T2 are drawn from the positive and negative electrode layers of the crystalline silicon cell, respectively; positive terminals T3 and T4 are drawn from the positive and negative electrode layers of the medium bandgap perovskite cell, respectively; and positive terminals T5 and T6 are drawn from the positive and negative electrode layers of the wide bandgap perovskite cell, respectively.
2. The tandem solar cell with spectral complementary synergistic performance as described in claim 1, characterized in that, The band gap range of the crystalline silicon solar cell is 1.1-1.2 eV.
3. The tandem solar cell with spectral complementary synergistic performance as described in claim 1, characterized in that, The bandgap range of the medium bandgap perovskite solar cell is 1.2-1.4 eV.
4. The tandem solar cell with spectral complementary synergistic performance as described in claim 1, characterized in that, The bandgap range of the wide-bandgap perovskite solar cell is 1.6-1.8 eV.
5. The tandem solar cell with spectral complementary synergistic performance as described in claim 1, characterized in that, The insulating and light-transmitting layer is either a silicon dioxide film or a polyethylene terephthalate film.
6. The tandem solar cell with spectral complementary synergistic performance as described in claim 1, characterized in that, The second insulating and light-transmitting layer is a silicon dioxide film or a polyethylene terephthalate film.