Semi-transparent perovskite cells, stacked cells comprising the same and methods of making the same

Abstract

The present application relates to the field of solar cells, in particular to a semi-transparent perovskite cell, a laminated cell comprising the same and a preparation method thereof, the perovskite light absorption layer of the semi-transparent perovskite solar cell comprises FAPbBr3 perovskite and a rubidium bromide additive; and the addition amount of the rubidium bromide is 0.5% to 1.5% based on the molar fraction of lead in the perovskite precursor. + Therefore, the halogen vacancies and lead-related defects in FAPbBr3 can be effectively embedded in the perovskite lattice or aggregated at the grain boundaries, the specific passivation can inhibit ion migration and interface charge accumulation, and the serious hysteresis effect existing in the current-voltage test of the cell can be greatly reduced, so that the difference between the forward and reverse scan efficiencies is significantly reduced.

Description

Technical Field

[0001] This invention relates to the field of solar cells, and more particularly to semi-transparent perovskite solar cells, tandem solar cells containing the same, and methods for their fabrication. Background Technology

[0002] In the field of photovoltaic technology, improving the photoelectric conversion efficiency of solar cells is a core objective that is constantly being pursued. Combining light-absorbing materials with different band gaps in a stacked manner can more fully utilize the solar spectrum and is considered an effective way to break through the theoretical efficiency limit of single-junction cells. Among them, the stacked structure consisting of a perovskite cell as the top cell and a crystalline silicon cell as the bottom cell has attracted much attention because it combines the advantages of both. To achieve efficient spectral utilization, the top perovskite cell needs to allow a sufficient number of long-wavelength photons to pass through to the bottom cell while also efficiently converting high-energy photons itself. This requires it to have "semi-transparent" properties, that is, to maintain a high average visible light transmittance (AVT) in the visible and near-infrared bands. Formamidinium lead bromide (FAPbBr3) perovskite, due to its wide band gap and relatively good phase stability, is considered one of the potential candidate materials for achieving high-efficiency semi-transparent top cells.

[0003] However, in actual research and development, semi-transparent perovskite solar cells based on FAPbBr3 face a series of challenges that restrict their full performance and reliable application in stacked structures. A significant problem is that these devices typically exhibit a noticeable hysteresis effect in current density-voltage (JV) testing, meaning there is a large difference between the photoelectric conversion efficiency measured by forward and reverse scanning. This hysteresis complicates the evaluation of the cell's true efficiency and reflects potential issues such as significant ion migration, high defect state density, or suboptimal interface contact within the perovskite active layer. These problems not only affect the accuracy of testing but are also closely related to the long-term performance stability of the device under actual operating conditions. Under continuous illumination, especially illumination containing ultraviolet components, and under thermal stress conditions, the performance degradation rate of these cells is often rapid, impacting their practical potential.

[0004] When a semi-transparent perovskite top cell is combined with a crystalline silicon bottom cell to construct a mechanically stacked four-terminal tandem solar cell, the impact of the aforementioned problems is further amplified. While the four-terminal structure avoids the complex tunnel junction fabrication between the top and bottom cells, it imposes stricter requirements on the performance uniformity, optical performance, and long-term operational stability of the top cell. The efficiency, transmittance, and spectral response stability of the top cell directly determine the light intensity and spectral distribution on the bottom cell, thus affecting the final output and reliability of the entire tandem system. If the hysteresis effect of the top cell is significant, its actual efficiency at the operating point will be difficult to accurately assess and maintain stably; if its performance degrades rapidly under light and thermal stress, the power generation capacity of the entire tandem system will continuously decline. Therefore, developing a semi-transparent FAPbBr3 perovskite solar cell with small hysteresis, accurate efficiency assessment, and stable performance under operating conditions is of great significance for realizing efficient and reliable perovskite / crystalline silicon four-terminal tandem solar cells and is a direction that deserves further exploration in this field. Existing technologies have not yet fully addressed these interconnected challenges, especially in finding effective ways to synergistically optimize optoelectronic performance, interface characteristics, optical transmittance, and environmental stability for the FAPbBr3 wide bandgap system. There is still room for improvement. Summary of the Invention

[0005] This application aims to overcome the significant current-voltage testing hysteresis effect, resulting in difficulties in evaluating the true performance, and the lack of long-term stability under light, ultraviolet, and heating conditions present in existing FAPbBr3 semi-transparent perovskite solar cells. Therefore, it provides a semi-transparent perovskite solar cell, a tandem solar cell containing the same, and a method for preparing the same to overcome the above-mentioned shortcomings.

[0006] To achieve the above-mentioned objectives, the present invention is implemented through the following technical solution: Firstly, the present invention provides a semi-transparent perovskite solar cell. The perovskite solar cell comprises a transparent conductive substrate, a hole transport layer, a perovskite light-absorbing layer, an electron transport layer, and a transparent top electrode; wherein... The perovskite light-absorbing layer comprises FAPbBr3 perovskite and rubidium bromide additive; and... The amount of rubidium bromide added is from 0.5% to 1.5% based on the molar fraction of lead in the perovskite precursor.

[0007] As described in the background section, in the prior art, the potential application of FAPbBr3-based semi-transparent perovskite solar cells as top cells in tandem structures faces a rather thorny contradiction: to obtain a high average visible light transmittance to meet the requirements of tandem spectral utilization, the thickness and quality of its light-absorbing layer need to be precisely controlled, but this is often accompanied by the problem of a high defect state density inside the perovskite thin film. This structural characteristic directly leads to a significant current-voltage hysteresis effect exhibited by such devices during testing and operation, making it difficult to accurately evaluate their true photoelectric conversion efficiency.

[0008] Based on the above-mentioned situation, this invention effectively overcomes the aforementioned shortcomings by selecting a specific form of rubidium bromide (RbBr) as an additive and precisely controlling its content within the range of 0.5% to 1.5% based on the lead molar fraction in the precursor. This is because, compared to other alkali metal halides, trace amounts of Rb... + The introduction of [a specific substance] can effectively embed into the perovskite lattice or aggregate at grain boundaries, specifically passivating halogen vacancies and lead-related defects in FAPbBr3, thereby suppressing ion migration and interfacial charge accumulation. In particular, if Rb [a specific substance]... + Insufficient addition of rubidium bromide may not be enough to effectively modify grain boundary and bulk defects in the film, while excessive addition may interfere with the normal formation of the FAPbBr3 bulk lattice or generate unnecessary insulating phases, thereby impairing the conductivity and optical performance of the device. Therefore, the core of this invention lies in utilizing rubidium bromide within this specific ratio range to effectively passivate deep-level defects in FAPbBr3 films, especially those related to halogen vacancies and uncoordinated lead, while potentially guiding grain growth to some extent, thereby fundamentally improving the quality of the film.

[0009] The implementation of this technical solution has brought about synergistic and multifaceted positive technical effects. The most direct manifestation is that the hysteresis effect in the current-voltage test of the modified semi-transparent perovskite solar cell is significantly reduced, and the electrical performance parameter curves obtained from forward and reverse scanning become more similar. This makes the efficiency evaluation results of the device more reliable and certain, laying the foundation for its use as a predictable unit in a tandem module. More importantly, this reduction in hysteresis effect does not come at the expense of initial photoelectric conversion efficiency; on the contrary, while maintaining or even optimizing the optical performance of the cell in the high-transmittance band, the cell's conversion efficiency, especially its performance parameters more representative under actual operating conditions, has been effectively improved. This indicates that the introduction of rubidium bromide, while passivating defects, does not introduce severe carrier recombination centers or excessively hinder charge transport. Furthermore, the benefits brought by defect passivation and ion migration suppression are continued in the long-term stability test of the device. The modified cell exhibits a slower performance degradation rate under accelerated aging conditions of continuous illumination and mild heating, and its environmental tolerance is effectively enhanced.

[0010] In summary, this invention, through a relatively simple yet ingenious technique of employing rubidium bromide as a specific additive and limiting its precise addition ratio, successfully addresses the traditional challenges of FAPbBr3 semi-transparent perovskite solar cells in terms of efficiency accuracy, performance level, and operational stability. These improvements are interconnected and mutually reinforcing, collectively aiming to fabricate more efficient and reliable perovskite optoelectronic devices, and providing a practical and effective solution for the actual advancement of this type of cell in stacked applications.

[0011] Preferably, the perovskite solar cell has an average visible light transmittance greater than 50% in the wavelength range of 300-1000 nm.

[0012] Preferably, the transparent conductive substrate is fluorine-doped tin oxide or indium-doped tin oxide.

[0013] Preferably, the hole transport layer is selected from NiO. x Or Me-4PACz.

[0014] Preferably, the electron transport layer comprises C60 or a composite layer consisting of PC61BM and BCP.

[0015] Secondly, the present invention also provides a method for preparing the aforementioned semi-transparent perovskite solar cell, comprising the following steps: - Provides a transparent conductive substrate; - A hole transport layer is formed on the substrate; - A perovskite light-absorbing layer is formed on the hole transport layer, wherein the perovskite light-absorbing layer is formed by spin-coating and annealing a precursor solution containing FABr, PbBr2 and rubidium bromide, wherein the amount of rubidium bromide added is 0.5% to 1.5% based on the molar fraction of lead; - An electron transport layer is formed on the perovskite light-absorbing layer; - A transparent top electrode is formed on the electron transport layer.

[0016] Preferably, the spin coating step is performed at a speed of 3000 rpm to 4000 rpm.

[0017] Preferably, the annealing step is performed at 100°C for 10 to 30 minutes.

[0018] Preferably, the solvent of the precursor solution is a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide; wherein, The volume ratio of N,N-dimethylformamide to dimethyl sulfoxide is 4:1.

[0019] Thirdly, the present invention also provides a semi-transparent perovskite / crystalline silicon four-terminal tandem solar cell, characterized in that... The device includes a semi-transparent perovskite solar cell as a top cell and a crystalline silicon bottom cell. The top and bottom cells are assembled by mechanical stacking, and the cathode of the perovskite cell and the anode of the crystalline silicon cell are isolated by an insulating encapsulation material.

[0020] Therefore, the present invention has the following beneficial effects: (1) Nearly completely eliminates the hysteresis effect: Trace Rb + The introduction of [a specific component] allows for effective embedding into the perovskite lattice or aggregation at grain boundaries, specifically passivating halogen vacancies and lead-related defects in FAPbBr3, and suppressing ion migration and interfacial charge accumulation. This results in a device exhibiting almost negligible JV hysteresis. With an effective area of ​​18.4 cm⁻¹... 2 In component testing, the difference in PCE between forward and reverse scans was as high as 2.814% for the control group without additives (FAPbBr3) (8.583% for reverse scan and 5.769% for forward scan). However, after adding RbBr, the difference was reduced to only 0.49% (8.824% for reverse scan and 8.334% for forward scan), and the hysteresis factor (HI = (PCE between reverse scan and forward scan) / PCE between reverse scans) was significantly reduced from approximately 32.8% to approximately 5.6%. (2) Simultaneously optimize and stabilize efficiency: This invention reveals that the addition of RbBr not only solves the hysteresis problem, but more importantly, it significantly improves the forward scan efficiency (representing a state closer to actual operation) of the battery from approximately 5.8% to over 8.3%. In contrast, while the addition of CsBr improves hysteresis (by a difference of 0.803%), its forward scan efficiency is only 5.918%, a negligible improvement. This demonstrates that RbBr has a unique and significant efficiency-enhancing effect on the FAPbBr3 system while eliminating hysteresis, while CsBr has limited effect. The device modified with RbBr exhibits a stable higher level for both forward scan PCE (8.334%) and reverse scan PCE (8.824%), resulting in a substantial leap in real-world performance. (3) Achieve excellent long-term stability: Based on the aforementioned defect passivation and ion migration suppression mechanisms, the RbBr-modified FAPbBr3 semi-transparent battery exhibits significantly enhanced environmental stability. During outdoor simulated aging tests in air at 65℃, its performance degradation rate is far lower than that of the unmodified control group and the CsBr-added group. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of a semi-transparent perovskite / crystalline silicon four-terminal stacked solar cell provided in an embodiment of the present invention. Detailed Implementation

[0022] The present invention will be further described below with reference to specific embodiments. Those skilled in the art will be able to implement the present invention based on these descriptions. Furthermore, the embodiments of the present invention described below are generally only some, not all, of the embodiments of the present invention. Therefore, all other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0023] Example 1 This embodiment provides a method for fabricating a semi-transparent perovskite solar cell, which includes the following steps: (1) Clean the 6*6 transparent conductive substrate (such as FTO) in an ultrasonic bath for 15 minutes in the order of glass cleaner, deionized water and ethanol, and then dry it with a nitrogen gun for later use.

[0024] (2) Preparation of a hole transport layer on a conductive substrate. First, a nickel oxide (NiOx) film with a thickness of approximately 15 nm was deposited on the substrate surface using physical vapor deposition (PVD). Immediately afterwards, the substrate was transferred to a glove box filled with N2, and the self-assembled molecule Me-4PACZ (0.5 mg / mL, solvent ethanol) was spin-coated onto the conductive substrate at 4000 rpm for 30 s, followed by annealing at 100 °C for 10 min. The hole transport layer was thus obtained.

[0025] (3) Preparation of a perovskite layer on the hole transport layer. FABr and PbBr2 were dissolved in 1 mL of a mixed solvent of DMF (N,N-dimethylformamide) and DMSO (dimethyl sulfoxide) in a volume ratio of 4:1. Rubidium bromide (RbBr) additive, equivalent to 1% of the molar amount of PbBr2, was added to this solution and stirred until completely dissolved to obtain a perovskite precursor solution. An appropriate amount of the perovskite precursor solution was rotated at 4000 rpm for 20 s, and an appropriate amount of antisolvent was rapidly added dropwise over 10 s. The precursor perovskite film was then transferred to a hot plate and annealed at 100 °C for 30 min in a glove box to obtain a perovskite light-absorbing layer.

[0026] (4) An electron transport layer was prepared on the perovskite light-absorbing layer. A PC61BM solution (20 mg / mL dissolved in chlorobenzene) was spin-coated onto the surface of the perovskite film at 3000 rpm for 30 s. Subsequently, a BCP solution (0.5 mg / mL, solvent ethanol) was spin-coated onto the surface of the perovskite film at 3000 rpm for 30 s. The film was then annealed at 100 °C for 5 min in a glove box to obtain the composite electron transport layer.

[0027] (5) Finally, a transparent electrode layer is fabricated on the electron transport layer. (The last part, "1×10," appears to be an error and doesn't need a direct translation.) -4 A 150nm ITO layer was deposited in vacuum at Pa to obtain a transparent electrode, thus completing the fabrication of a semi-transparent perovskite solar cell. The component structure is as follows: Figure 1 As shown in the perovskite top solar cell, the effective area of ​​the module is defined as 18.4 cm² using a mask. 2 .

[0028] Example 2 This embodiment provides a method for fabricating a semi-transparent perovskite solar cell, which includes the following steps: (1) Clean the 6*6 transparent conductive substrate (such as ITO) in an ultrasonic bath for 15 minutes in the order of glass cleaner, deionized water and ethanol, and then dry it with a nitrogen gun for later use.

[0029] (2) Preparation of a hole transport layer on a conductive substrate. The conductive glass substrate obtained in (1) was treated with ozone for 30 min, and then immediately transferred to a glove box filled with N2. The self-assembled molecule Me-4PACZ (0.5 mg / mL, solvent ethanol) was spin-coated onto the conductive substrate at 3000 rpm for 40 s, and annealed at 90 °C for 40 min. The hole transport layer was obtained.

[0030] (3) Preparation of a perovskite layer on the hole transport layer. FABr and PbBr2 were dissolved in 1 mL of a mixed solvent of DMF (N,N-dimethylformamide) and DMSO (dimethyl sulfoxide) in a volume ratio of 4:1. Rubidium bromide (RbBr) additive, equivalent to 1.5% of the molar amount of PbBr2, was added to this solution and stirred until completely dissolved to obtain a perovskite precursor solution. An appropriate amount of the perovskite precursor solution was rotated at 4000 rpm for 20 s, and an appropriate amount of antisolvent was rapidly added dropwise over 10 s. The precursor perovskite film was then transferred to a hot plate and annealed at 110 °C for 20 min in a glove box to obtain a perovskite light-absorbing layer.

[0031] (4) An electron transport layer was prepared on the perovskite light-absorbing layer. A PC61BM solution (20 mg / mL dissolved in chlorobenzene) was spin-coated onto the surface of the perovskite film at 3000 rpm for 30 s. Subsequently, a BCP solution (0.5 mg / mL, solvent ethanol) was spin-coated onto the surface of the perovskite film at 3000 rpm for 30 s. The film was then annealed at 100 °C for 5 min in a glove box to obtain the composite electron transport layer.

[0032] (5) Finally, a transparent electrode layer is fabricated on the electron transport layer. (The last part, "1×10," appears to be an error and doesn't need a direct translation.) -4 A 150nm ITO layer was deposited in vacuum at Pa to obtain a transparent electrode, thus completing the fabrication of a semi-transparent perovskite solar cell. The component structure is as follows: Figure 1 As shown in the perovskite top solar cell, the effective area of ​​the module is defined as 18.4 cm² using a mask. 2 .

[0033] Example 3 This embodiment provides a method for fabricating a semi-transparent perovskite solar cell, which includes the following steps: (1) The glass substrate coated with fluorine-doped tin oxide (FTO) was ultrasonically cleaned in glass cleaner, deionized water and ethanol for 15 minutes each, and then dried with nitrogen. Subsequently, the substrate was treated in an ozone treatment device for 30 minutes.

[0034] (2) A hole transport layer was prepared on a conductive substrate. The prepared NiOx nanoparticle colloidal aqueous solution was spin-coated on the treated FTO substrate at a speed of 4000 rpm for 30 seconds, and then annealed in air at 150°C for 30 minutes to form a NiOx hole transport layer.

[0035] (3) Preparation of a perovskite layer on the hole transport layer. FABr and PbBr2 were dissolved in 1 mL of a mixed solvent of DMF (N,N-dimethylformamide) and DMSO (dimethyl sulfoxide) in a volume ratio of 4:1. Rubidium bromide (RbBr) additive, equivalent to 0.5% of the molar amount of PbBr2, was added to this solution and stirred until completely dissolved to obtain a perovskite precursor solution. An appropriate amount of the perovskite precursor solution was rotated at 4000 rpm for 20 s, and an appropriate amount of antisolvent was rapidly added dropwise over 10 s. The perovskite precursor film was then transferred to a hot plate and annealed at 90 °C for 40 min in a glove box to obtain a perovskite light-absorbing layer.

[0036] (4) Prepare an electron transport layer on the perovskite light-absorbing layer. Transfer the sample with the completed perovskite layer to a vacuum evaporation apparatus and perform evaporation at 1×10⁻⁶. -4 Under a vacuum of Pa, a C60 thin film with a thickness of about 20 nm and a copper bath (BCP) thin film with a thickness of about 8 nm were sequentially thermally deposited as an electron transport layer and a hole blocking layer.

[0037] (5) Finally, a transparent electrode layer is fabricated on the electron transport layer. Without disrupting the vacuum, gold (Au) with a thickness of approximately 12 nm is thermally deposited using a mask as a semi-transparent metal electrode, or ITO with a thickness of approximately 150 nm is deposited as a fully transparent electrode, thus completing the cell fabrication. The effective device area defined by the mask is 18.4 cm². 2 .

[0038] Comparative Example 1: Additive-free FAPbBr3 perovskite solar cells The only difference from Example 1 is that no additives were used in the perovskite precursor solution; all other aspects are the same, resulting in a semi-transparent perovskite solar cell.

[0039] Comparative Example 2: FAPbBr3 perovskite solar cells with added CsBr The only difference from Example 1 is the addition of 0.5 to 1.5% of rubidium cesium bromide (CsBr) additive to the perovskite precursor solution, which is equivalent to the number of moles of PbBr2. All other aspects are the same, resulting in a semi-transparent perovskite solar cell.

[0040] Comparative Example 3 The only difference from Example 1 is that the amount of rubidium bromide (RbBr) additive added to the perovskite precursor solution is equivalent to 2% of the molar number of PbBr2, and all other aspects are the same, resulting in a semi-transparent perovskite solar cell.

[0041] Comparative Example 4 The only difference from Example 1 is that the amount of rubidium bromide (RbBr) additive added to the perovskite precursor solution is equivalent to 0.2% of the molar number of PbBr2, and all other aspects are the same, resulting in a semi-transparent perovskite solar cell.

[0042] Examples 1-3 and Comparative Examples 1-4 were tested using the following methods: Average transmittance test method: UV-vis spectrophotometer (carry 4000), scanning wavelength 300-1000nm, to obtain transmittance curve.

[0043] Device efficiency testing method: Under standard illumination conditions (AM1.5, 1000W / cm²), 2 The test involves irradiating the battery under test with a solar simulator, applying a linear scan voltage (-0.2 V to 1.2 V) to the battery using a digital source meter or semiconductor parameter analyzer, recording the current density-voltage (JV) curve, and reading parameters such as VOC and JSC.

[0044] Photovoltaic stability testing methods: Simulated outdoor testing of perovskite solar cells was conducted under standard test conditions (STC), including AM1.5 and 1000 W / m. 2 Irradiance and battery temperature of 65°C were measured, and stability and performance were evaluated according to IEC 61215 or IEC 61646 standards to ensure that the test results are consistent with the real outdoor environment.

[0045] The test results are shown in Table 1 below: Table 1

[0046] The RbBr-added batteries prepared in Examples 1-3 exhibited significantly smaller differences in the forward and reverse scan JV curves compared to Comparative Examples 1 and 2, demonstrating extremely low hysteresis. Simultaneously, their photoelectric conversion efficiency based on forward scanning (closer to actual operating conditions) was significantly higher than that of Comparative Example 1 (without additives) and Comparative Example 2 (with CsBr). The average visible light transmittance (AVT) of all the batteries in these examples was higher than 50%, meeting the requirement of semi-transparency. In stability tests, the efficiency decay rates of the batteries in Examples 1 and 2 were significantly slower than those of the two comparative examples.

[0047] From Comparative Example 3 (addition amount 2.0%), we can see that when the RbBr addition amount is significantly higher than 1.5%, the excess rubidium ions (RbBr) will cause adverse reactions. +It may not be able to completely and effectively integrate into the FAPbBr3 lattice or remain at the grain boundaries for passivation, and may instead form non-perovskite insulating impurities or excessively interfere with the normal growth of perovskite crystals. This is expected to lead to a decrease in the crystal quality of the perovskite film, an increase in defects, and consequently, a reduction in the photoelectric conversion efficiency of the device, a deterioration in the fill factor, and even an impact on the film's uniformity and transmittance. This comparative example can be used to demonstrate that excessive addition is not beneficial and may even impair performance, thus clarifying the upper limit of the addition ratio.

[0048] As shown in Comparative Example 4 (0.2% addition), when the RbBr addition is below 0.5%, the additive content is insufficient to effectively and uniformly modify the entire perovskite active layer. Its effect on passivating bulk and interface defects and inhibiting ion migration is expected to be very limited. Therefore, the device may still exhibit a relatively obvious current-voltage hysteresis effect similar to Comparative Example 1 without any additives, and the improvement in long-term stability will also be insignificant. This comparative example can be used to demonstrate that excessively low addition amounts cannot achieve the expected technical effects of this invention, thus clarifying the lower limit of the addition ratio.

[0049] Fabrication of a semi-transparent perovskite / crystalline silicon four-terminal tandem solar cell: This embodiment provides a four-terminal tandem cell consisting of a semi-transparent perovskite cell as the top cell described in Examples 1-3 and Comparative Examples 1-4, and a commercial crystalline silicon heterojunction (HJT) solar cell.

[0050] 1. Preparation of top cell: A semi-transparent FAPbBr3 perovskite solar cell module was prepared using the same process as in Examples 1-3 and Comparative Examples 1-4.

[0051] 2. Prepare the base cell: Prepare a commercial HJT crystalline silicon cell with an effective area of ​​equivalent size.

[0052] 3. Mechanical Stacking and Encapsulation: The prepared semi-transparent perovskite top cell is placed on top of the crystalline silicon bottom cell, optically coupled but electrically isolated. A transparent optical adhesive is used to bond them at the edges, ensuring physical isolation between the perovskite cell's cathode (top ITO) and the crystalline silicon cell's anode through an insulating encapsulation material (such as ethylene-vinyl acetate copolymer, EVA) to prevent short circuits. Finally, the stack is placed in a laminator for lamination and encapsulation, resulting in... Figure 1 The four-terminal tandem solar cell is shown. Subsequently, the performance of the semi-transparent perovskite / crystalline silicon four-terminal tandem solar cell was tested, and the test results are shown in Table 2 below: Test method: Table 2

[0053] The data in Table 2 fully demonstrate that the semi-transparent perovskite top cell prepared using the present invention (with the addition of 0.5%-1.5% RbBr) is key to constructing a high-efficiency perovskite / crystalline silicon four-terminal tandem solar cell. While achieving high efficiency, low hysteresis, and good stability in the top cell itself, it maximizes the efficiency of the bottom cell, thereby significantly improving the overall output efficiency of the tandem system. Furthermore, by using an ultra-wide bandgap perovskite device as the top cell in the four-terminal tandem structure, the present invention effectively optimizes the spectral distribution mechanism between the top and bottom cells. This structure ensures high-efficiency output from the top cell while minimizing photon energy loss, significantly improving the spectral response efficiency of the bottom silicon-based cell and the overall energy conversion density of the tandem system, demonstrating the significant technological advancement of the present invention in improving photovoltaic device performance and industrial applications.

[0054] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A semi-transparent perovskite solar cell, characterized in that, The perovskite solar cell comprises a transparent conductive substrate, a hole transport layer, a perovskite light-absorbing layer, an electron transport layer, and a transparent top electrode; wherein... The perovskite light-absorbing layer comprises FAPbBr3 perovskite and rubidium bromide additive; and... The amount of rubidium bromide added is from 0.5% to 1.5% based on the molar fraction of lead in the perovskite precursor.

2. The semi-transparent perovskite solar cell according to claim 1, characterized in that, The perovskite solar cell has an average visible light transmittance of greater than 50% in the wavelength range of 300-1000 nm.

3. The semi-transparent perovskite solar cell according to claim 1, characterized in that, The transparent conductive substrate is fluorine-doped tin oxide or indium-doped tin oxide.

4. The semi-transparent perovskite solar cell according to claim 1, characterized in that, The hole transport layer is selected from NiO. x Or Me-4PACz.

5. The semi-transparent perovskite solar cell according to claim 3, characterized in that, The electron transport layer comprises C60 or a composite layer consisting of PC61BM and BCP.

6. A method for preparing a semi-transparent perovskite solar cell as described in any one of claims 1-5, characterized in that, Includes the following steps: - Provides a transparent conductive substrate; - A hole transport layer is formed on the substrate; - A perovskite light-absorbing layer is formed on the hole transport layer, wherein the perovskite light-absorbing layer is formed by spin-coating and annealing a precursor solution containing FABr, PbBr2 and rubidium bromide, wherein the amount of rubidium bromide added is 0.5% to 1.5% based on the molar fraction of lead; - An electron transport layer is formed on the perovskite light-absorbing layer; - A transparent top electrode is formed on the electron transport layer.

7. The method according to claim 6, characterized in that, The spin coating process is performed at a speed of 3000 to 4000 rpm.

8. The method according to claim 6, characterized in that, The annealing step is performed at 90°C to 110°C for 20 to 40 minutes.

9. The method according to claim 6, characterized in that, The solvent for the precursor solution is a mixture of N,N-dimethylformamide and dimethyl sulfoxide.

10. A semi-transparent perovskite / crystalline silicon four-terminal tandem solar cell, characterized in that, The invention includes a semi-transparent perovskite solar cell as described in any one of claims 1-5 as a top cell, and a crystalline silicon bottom cell, wherein the top cell and the bottom cell are assembled by mechanical stacking, and the cathode of the perovskite cell and the anode of the crystalline silicon cell are isolated by an insulating encapsulation material.

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