Perovskite / crystalline silicon tandem solar cell

Abstract

The application discloses a perovskite / crystalline silicon laminated solar cell and relates to the technical field of solar cells. The cell comprises a crystalline silicon bottom cell, an intermediate layer and a perovskite top cell arranged in a stack from bottom to top, and the intermediate layer comprises a first ITO layer, an Au layer and a second ITO layer. The work function of the first ITO layer is any value in the range of 4.0 eV-4.4 eV, and the work function of the second ITO layer is any value in the range of 4.6 eV-4.8 eV, so that the intermediate layer forms an energy level matching with the crystalline silicon bottom cell and a hole transport layer, respectively, and a tunneling structure is formed among the hole transport layer, the second ITO layer and the Au layer. The application can realize good energy level matching between the intermediate layer and the perovskite top cell and the crystalline silicon bottom cell, reduce the interface barrier and improve the carrier recombination and transport efficiency while ensuring high optical transmittance.

Description

Technical Field

[0001] This invention relates to the field of solar cell technology, and more specifically to a perovskite / crystalline silicon tandem solar cell. Background Technology

[0002] In recent years, with the continuous development of photovoltaic technology, the tandem integration of perovskite top cells and crystalline silicon bottom cells has become a key research direction in the photovoltaic field. This integration significantly improves light energy utilization through segmented absorption of the solar spectrum, breaking the Shockley-Quisser limit on the efficiency of single-junction solar cells. In the perovskite / crystalline silicon tandem solar cell structure, the intermediate layer is a crucial functional layer connecting the perovskite top cell and the crystalline silicon bottom cell. It not only needs to achieve electrical series recombination between the top and bottom cells but also ensure efficient light transmission within the device. Therefore, the intermediate layer simultaneously undertakes the dual functions of optical coupling and electrical recombination: optically, it needs high transmittance in the near-infrared band to ensure that long-wavelength light can pass through the top cell and be absorbed by the crystalline silicon bottom cell, thereby increasing the short-circuit current of the device; electrically, the intermediate layer needs to provide efficient carrier recombination channels, allowing holes from the perovskite top cell and electrons from the crystalline silicon bottom cell to recombine rapidly at the intermediate layer, maintaining effective current separation and collection in the series structure.

[0003] In existing technologies, the interlayer typically employs a metal layer or a transparent conductive oxide layer as a composite structure. For example, when gold is used as the interlayer material, although it has low resistivity and good conductivity, the metal and the hole transport layer of the perovskite material are prone to forming a contact interface with many interface defects, leading to significant nonradiative recombination losses and thus reducing the open-circuit voltage of the device. Simultaneously, metal atoms may diffuse during device operation, affecting the passivation structure of the crystalline silicon base cell surface, thereby reducing the minority carrier lifetime and stability of the base cell. Furthermore, noble metal materials are expensive, hindering large-scale applications. On the other hand, using transparent conductive oxides as the interlayer, such as indium tin oxide (ITO), is widely used in tandem solar cells due to its high optical transmittance and good conductivity. However, a single ITO interlayer still has certain limitations in practical applications. For example, the work function of ITO often fails to achieve ideal energy level matching with both the hole transport layer of the perovskite top cell and the electron transport interface of the crystalline silicon bottom cell, easily forming an energy barrier at the interface. This leads to carrier accumulation at the interface, affecting the efficient transport and recombination of electrons and holes. Furthermore, the ITO deposition process may cause sputtering damage to the passivation layer on the bottom cell surface, which can also reduce device performance to some extent.

[0004] Therefore, the intermediate layer structure in existing perovskite / crystalline silicon tandem solar cells still has shortcomings in terms of optical transmittance, electrical recombination efficiency, and bandgap matching, making it difficult to simultaneously meet the requirements of high transmittance and efficient carrier recombination, thus limiting the further improvement of the overall photoelectric conversion efficiency of perovskite / crystalline silicon tandem solar cells. Summary of the Invention

[0005] One objective of this invention is to provide a perovskite / crystalline silicon tandem solar cell that solves the technical problem in the prior art where the intermediate layer of a perovskite / crystalline silicon tandem solar cell is difficult to achieve both high optical transmittance and good energy level matching, resulting in low interfacial carrier recombination efficiency, large interfacial barrier, and limited device photoelectric conversion efficiency.

[0006] Another objective of this invention is to enable the intermediate layer to not only form an energy level matching relationship that gradually changes from the crystalline silicon bottom cell side to the perovskite top cell side in terms of energy level structure, but also to form a nanoscale composite interface suitable for carrier tunneling recombination in terms of structural size.

[0007] According to the purpose of this invention, a perovskite / crystalline silicon tandem solar cell is provided, comprising a crystalline silicon bottom cell, an intermediate layer, and a perovskite top cell stacked from bottom to top. Along the bottom-to-top direction, the crystalline silicon bottom cell includes a first electrode layer, a p-type doped amorphous silicon layer, a first intrinsic amorphous silicon layer, an n-type doped silicon absorber layer, a second intrinsic amorphous silicon layer, and an n-type doped silicon-based thin film layer stacked sequentially. The intermediate layer includes a first ITO layer, an Au layer, and a second ITO layer stacked sequentially. The perovskite top cell includes a hole transport layer, a perovskite absorber layer, an electron transport layer, a second electrode layer, and an antireflection layer stacked sequentially.

[0008] The work function of the first ITO layer is any value between 4.0 eV and 4.4 eV, and the work function of the second ITO layer is any value between 4.6 eV and 4.8 eV, so that the intermediate layer forms an energy level match with the crystalline silicon bottom cell and the hole transport layer respectively, and a tunneling structure is formed between the hole transport layer, the second ITO layer and the Au layer.

[0009] Optionally, the thickness of the first ITO layer and the second ITO layer are both any value between 2.5nm and 3.0nm, and the thickness of the Au layer is any value between 0.5nm and 2.0nm.

[0010] Optionally, the first ITO layer can be modified by introducing a nitrogen-containing polymer to form a surface dipole or by adjusting the oxygen flow rate during the deposition process to control the work function.

[0011] Optionally, the second ITO layer can be modified by chlorine atoms to form an In-Cl dipole or by adjusting the oxygen flow rate during the deposition process to control the work function.

[0012] Optionally, the n-type doped silicon-based thin film layer is an n-type doped amorphous silicon layer or an n-type doped nanocrystalline silicon layer.

[0013] Optionally, the hole transport layer is made of MeO-2PACz, 4PABCz and its derivatives, PTAA or NiO. x .

[0014] Optionally, the thickness of the perovskite absorber layer is any value between 500 nm and 800 nm;

[0015] The thickness of the electron transport layer is any value between 10nm and 40nm, and the material is C. 60 At least one of PCBM or SnO2;

[0016] The thickness of the second electrode layer is any value between 80nm and 150nm, and the material is at least one of ITO, AZO or IZO;

[0017] The thickness of the antireflection layer is any value between 80nm and 150nm, and the material is at least one of MgF2, SiO2, or Al2O3.

[0018] Optionally, the thickness of the intrinsic amorphous silicon layer is any value between 3nm and 10nm, and the thickness of both the p-type doped amorphous silicon layer and the n-type doped silicon-based thin film layer is any value between 5nm and 20nm.

[0019] Optionally, the thickness of the n-type doped silicon absorber layer is any value between 150 μm and 300 μm.

[0020] Optionally, the thickness of the first electrode layer is any value between 80nm and 150nm, and the material is Ag, Al, or Ag / Al composite metal.

[0021] This invention provides a multilayer composite intermediate layer composed of a first ITO layer, an Au layer, and a second ITO layer between the crystalline silicon bottom cell and the perovskite top cell in a perovskite / crystalline silicon tandem solar cell. The work functions of the first and second ITO layers are limited to 4.0 eV-4.4 eV and 4.6 eV-4.8 eV, respectively. This multilayer structure achieves synergistic effects both electrically and optically, enabling energy level matching between the intermediate layer and both the crystalline silicon bottom cell and the hole transport layer. Furthermore, a tunneling structure is formed between the hole transport layer, the second ITO layer, and the Au layer. This ensures high light transmittance while achieving energy level matching and efficient carrier recombination between the crystalline silicon bottom cell and the perovskite top cell, reducing the interface barrier and series resistance, improving carrier transport and recombination efficiency, and ultimately enhancing the photoelectric conversion performance of the tandem solar cell.

[0022] Furthermore, the thickness of the first ITO layer and the second ITO layer of the present invention is any value between 2.5 nm and 3.0 nm, and the thickness of the Au layer is any value between 0.5 nm and 2.0 nm. By designing the above thickness range in conjunction with the work function gradient control of the first ITO layer (4.0 eV-4.4 eV) and the second ITO layer (4.6 eV-4.8 eV), the intermediate layer not only forms an energy level matching relationship that gradually changes from the crystalline silicon bottom cell side to the perovskite top cell side in terms of energy level structure, but also forms a nanoscale composite interface suitable for carrier tunneling recombination in terms of structural size.

[0023] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0024] The following sections will describe some specific embodiments of the invention in detail by way of example and not limitation, with reference to the accompanying drawings. The same reference numerals in the drawings denote the same or similar parts or portions. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings:

[0025] Figure 1 This is a schematic structural diagram of a perovskite / crystalline silicon tandem solar cell according to an embodiment of the present invention;

[0026] Figure 2 This is a schematic performance band structure diagram of a perovskite / crystalline silicon tandem solar cell according to an embodiment of the present invention;

[0027] Figure 3 This is a schematic performance band structure diagram of a perovskite / crystalline silicon tandem solar cell according to Embodiment 1 of the present invention;

[0028] Figure 4This is a schematic performance band structure diagram of a perovskite / crystalline silicon tandem solar cell according to Comparative Example 1 of the present invention;

[0029] Figure 5 These are current-voltage curves of perovskite / crystalline silicon tandem solar cells according to Embodiment 1 and Comparative Example 1 of the present invention.

[0030] Figure 6 These are current-voltage curves of perovskite / crystalline silicon tandem solar cells according to Embodiment 1 and Comparative Examples 2-3 of the present invention.

[0031] Figure 7 The figures are current-voltage curves of perovskite / crystalline silicon tandem solar cells according to Embodiment 1 and Comparative Examples 4-5 of the present invention.

[0032] Figure label:

[0033] 100-Perovskite / crystalline silicon tandem solar cell, 10-Crystalline silicon bottom cell, 20-Intermediate layer, 30-Perovskite top cell, 40-Conduction band, 50-Valve band, 60-Tunneling structure, 11-First electrode layer, 12-P-type doped amorphous silicon layer, 13-First intrinsic amorphous silicon layer, 14-N-type doped silicon absorber layer, 15-Second intrinsic amorphous silicon layer, 16-N-type doped silicon-based thin film layer, 21-First ITO layer, 22-Au layer, 23-Second ITO layer, 31-Hole transport layer, 32-Perovskite absorber layer, 33-Electron transport layer, 34-Second electrode layer, 35-Antireflection layer. Detailed Implementation

[0034] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0035] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, it should be noted that, for ease of description, only the parts relevant to this application are shown in the accompanying drawings, not the entire structure. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this application.

[0036] The terms “comprising” and “having”, and any variations thereof, used in this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus.

[0037] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0038] Figure 1 This is a schematic structural diagram of a perovskite / crystalline silicon tandem solar cell according to an embodiment of the present invention. Figure 2 This is a schematic performance band structure diagram of a perovskite / crystalline silicon tandem solar cell according to an embodiment of the present invention.

[0039] like Figure 1 As shown, the present invention provides a perovskite / crystalline silicon tandem solar cell 100, comprising a crystalline silicon bottom cell 10, an intermediate layer 20, and a perovskite top cell 30 arranged from bottom to top. Along the bottom-to-top direction, the crystalline silicon bottom cell 10 includes a first electrode layer 11, a p-type doped amorphous silicon layer 12, a first intrinsic amorphous silicon layer 13, an n-type doped silicon absorber layer 14, a second intrinsic amorphous silicon layer 15, and an n-type doped silicon-based thin film layer 16 arranged in sequence. The intermediate layer 20 includes a first ITO layer 21, an Au layer 22, and a second ITO layer 23 arranged in sequence. The perovskite top cell 30 includes a hole transport layer 31, a perovskite absorber layer 32, an electron transport layer 33, a second electrode layer 34, and an antireflection layer 35 arranged in sequence. The work function of the first ITO layer 21 is any value between 4.0 eV and 4.4 eV, and the work function of the second ITO layer 23 is any value between 4.6 eV and 4.8 eV, so that the intermediate layer 20 forms energy level matching with the crystalline silicon bottom cell 10 and the hole transport layer 31, respectively, and a tunneling structure 60 is formed between the hole transport layer 31, the second ITO layer 23, and the Au layer 22 (see reference). Figure 2Here, the work function of the first ITO layer 21 can be 4.0 eV, 4.1 eV, 4.2 eV, 4.3 eV or 4.4 eV, or any other value between 4.0 eV and 4.0 eV; the work function of the second ITO layer 23 can be 4.6 eV, 4.65 eV, 4.7 eV, 4.75 eV or 4.8 eV, or any other value between 4.6 eV and 4.8 eV; and the work function of the Au layer 22 is 4.8 eV.

[0040] In this embodiment, a multilayer composite intermediate layer 20 composed of a first ITO layer 21, an Au layer 22, and a second ITO layer 23 is provided between the crystalline silicon bottom cell 10 and the perovskite top cell 30 of the perovskite / crystalline silicon tandem solar cell 100. The work functions of the first ITO layer 21 and the second ITO layer 23 are limited to 4.0 eV-4.4 eV and 4.6 eV-4.8 eV, respectively. This multilayer structure achieves synergy in electrical and optical aspects, enabling the intermediate layer 20 to achieve energy level matching with the crystalline silicon bottom cell 10 and the hole transport layer 31, respectively. A tunneling structure 60 is formed between the hole transport layer 31, the second ITO layer 23, and the Au layer 22. This ensures high light transmittance while achieving energy level matching and efficient carrier recombination between the crystalline silicon bottom cell 10 and the perovskite top cell 30, reducing the interface barrier and series resistance, improving carrier transport and recombination efficiency, and thus enhancing the photoelectric conversion performance of the perovskite / crystalline silicon tandem solar cell 100.

[0041] In this embodiment, a three-layer composite intermediate layer 20 consisting of a first ITO layer 21, an Au layer 22, and a second ITO layer 23 is disposed between the crystalline silicon bottom cell 10 and the perovskite top cell 30. The first ITO layer 21 is positioned closer to the n-type doped silicon-based thin film layer 16, and the second ITO layer 23 is positioned closer to the hole transport layer 31. This creates a multilayer structure with a gradually changing interface structure from the crystalline silicon bottom cell 10 side to the perovskite top cell 30 side. The work function of the first ITO layer 21 is set to 4.0 eV-4.4 eV, which allows for good energy level matching with the n-type doped silicon-based thin film layer 16 of the crystalline silicon bottom cell 10, thus facilitating electron transport and reducing the interface barrier. The work function of the second ITO layer 23 is set to 4.6 eV-4.8 eV, which allows for good energy level matching with the hole transport layer 31, thus facilitating hole transport and extraction. By using the gradient design of ITO layers with different work functions, the intermediate layer 20 forms suitable energy level structures from the crystalline silicon bottom cell 10 to the perovskite top cell 30, thereby improving the interface energy level mismatch problem between different functional layers in the stacked structure.

[0042] In this embodiment, an ultrathin Au layer 22 is disposed between the first ITO layer 21 and the second ITO layer 23, so that the hole transport layer 31, the second ITO layer 23, and the Au layer 22 form a tunneling structure 60, thereby enabling electrons and holes to recombine rapidly at the intermediate layer 20 through a tunneling mechanism. Since the Au layer 22 has high conductivity, it can provide an effective carrier recombination center while maintaining a low thickness, thereby reducing the series resistance of the intermediate layer 20 and improving the recombination efficiency. Simultaneously, the recombination structure formed by the Au layer 22, the first ITO layer 21, and the second ITO layer 23 helps to form a stable electrical connection path, enabling carriers from the perovskite top cell 30 and the crystalline silicon bottom cell 10 to recombine efficiently at the intermediate layer 20 and complete current transport.

[0043] Furthermore, through parameterized design of the work function ranges of the first ITO layer 21 and the second ITO layer 23, the multilayer composite intermediate layer 20 not only forms a composite layer in structure but also achieves a gradient modulation effect in energy level distribution. This allows it to form a synergistic matching relationship with the n-type doped silicon-based thin film layer 16 of the crystalline silicon bottom cell 10 and the hole transport layer 31 of the perovskite top cell 30. This multilayer structure and the work function parameter design work together to ensure that the intermediate layer 20 possesses both good electrical recombination performance and low optical loss. This ensures that light can effectively pass through the intermediate layer 20 into the crystalline silicon bottom cell 10 while improving carrier recombination efficiency and reducing energy loss. Ultimately, this achieves efficient photoelectric coupling between the perovskite top cell 30 and the crystalline silicon bottom cell 10, improving the overall photoelectric conversion efficiency of the perovskite / crystalline silicon tandem solar cell 100.

[0044] like Figure 2 As shown, from the perspective of device thickness, the band distribution in this embodiment exhibits the following characteristics: In the region of the crystalline silicon bottom cell 10, the conduction band 40 is mainly tilted upward to promote electron transport; in the region of the intermediate layer 20, an energy level gradient is formed through the combination of ITO layers with different work functions, and a recombination center is formed at the Au layer 22, i.e., holes and electrons are transported to the intermediate layer 20 respectively; in the region of the perovskite top cell 30, the valence band 50 is tilted downward to promote hole transport to the intermediate layer 20. This forms a band structure where electrons from the conduction band 40 of the perovskite top cell 30 and holes from the valence band 50 of the crystalline silicon bottom cell 10 recombine at a low barrier at the intermediate layer 20, while ensuring that electrons and holes can transport in favorable directions within their respective cells, thereby achieving an efficient carrier separation, transport, and recombination mechanism throughout the entire device thickness direction. Here, the electron transport direction is indicated by arrow a, and the hole transport direction is indicated by arrow b.

[0045] In a further embodiment, the thickness of the first ITO layer 21 and the second ITO layer 23 is any value between 2.5nm and 3.0nm, and the thickness of the Au layer 22 is any other value between 0.5nm and 2.0nm. That is, the thickness of the first ITO layer 21 and the second ITO layer 23 can be 2.5nm, 2.6nm, 2.7nm, 2.8nm, 2.9nm, or 3.0nm, or any other value between 2.5nm and 3.0nm. Here, the thickness of the first ITO layer 21 and the thickness of the second ITO layer 23 can be the same or different, and the thickness of the Au layer 22 can be 0.5nm, 1.5nm, 1.6nm, 1.7nm, 1.8nm, 1.9nm, or 2.0nm, or any other value between 0.5nm and 2.0nm. By combining the above-mentioned thickness range design with the gradient control of the work function of the first ITO layer 21 (4.0 eV-4.4 eV) and the work function of the second ITO layer 23 (4.6 eV-4.8 eV), the intermediate layer 20 not only forms an energy level matching relationship that gradually changes from the crystalline silicon bottom cell 10 side to the perovskite top cell 30 side in terms of energy level structure, but also forms a nanoscale composite interface suitable for carrier tunneling recombination in terms of structural size.

[0046] Specifically, a stable tunneling structure 60 can be formed between the thinner second ITO layer 23 and the Au layer 22, allowing holes from the perovskite top cell 30 to recombine efficiently with electrons from the crystalline silicon bottom cell 10 near the Au layer 22 via a tunneling mechanism. Simultaneously, the energy level matching relationship between the first ITO layer 21 and the crystalline silicon bottom cell 10, combined with its nanoscale thickness, facilitates the smooth transport of electrons to the Au layer 22 to participate in the recombination process. Thus, through the synergistic effect of the thickness parameter design and work function gradient design of the three-layer structure (first ITO layer 21 / Au layer 22 / second ITO layer 23), the intermediate layer 20 simultaneously possesses good optical transmittance, a stable conductive channel, and efficient carrier recombination capability, thereby further reducing the interface barrier and series resistance, and improving the carrier transport efficiency and overall photoelectric conversion performance of the perovskite / crystalline silicon tandem solar cell 100.

[0047] Furthermore, the thicknesses of the first ITO layer 21 and the second ITO layer 23 are set within the range of 2.5 nm to 3.0 nm. This ensures both film continuity and high light transmittance, allowing incident light to effectively pass through the intermediate layer 20 and enter the crystalline silicon bottom cell 10 for further absorption, thereby reducing parasitic optical losses in the intermediate layer 20. Simultaneously, this thickness range ensures that both the first ITO layer 21 and the second ITO layer 23 possess stable conductivity and interface coverage, thus providing a stable channel for carrier transport. On the other hand, the thickness of the Au layer 22 is set within the range of 0.5 nm to 2.0 nm, placing the Au layer 22 in an ultra-thin metal layer state. This maintains high conductivity while avoiding the enhanced light absorption caused by an excessively thick Au layer 22, thus balancing electrical recombination and optical transmittance.

[0048] In a further embodiment, the first ITO layer 21 is modified by introducing a nitrogen-containing polymer to form a surface dipole or by adjusting the oxygen flow rate during the deposition process to regulate the work function. In this embodiment, the work function is adjusted by modifying the interface of the first ITO layer 21 or by controlling the deposition process, thereby further optimizing the energy level matching relationship between the intermediate layer 20 and the crystalline silicon bottom cell 10. Specifically, by introducing a nitrogen-containing polymer to modify the surface of the first ITO layer 21, a stable interface dipole structure can be formed on the surface of the first ITO layer 21. This interface dipole can change the potential distribution on the surface of the first ITO layer 21, thereby effectively regulating its work function and keeping the work function of the first ITO layer 21 stable in the range of 4.0 eV-4.4 eV. This better matches the energy level structure of the n-type doped silicon-based thin film layer 16 in the crystalline silicon bottom cell 10, thereby reducing the interface barrier, promoting the transport of electrons from the crystalline silicon bottom cell 10 to the intermediate layer 20, and improving the carrier transport efficiency.

[0049] In this embodiment, by adjusting the oxygen flow rate during the deposition of the first ITO layer 21, the oxygen vacancy concentration and carrier concentration in the ITO film can be changed, thereby controlling the adjustment of its work function. This allows the first ITO layer 21 to maintain good conductivity while achieving energy level matching with the crystalline silicon bottom cell 10. The aforementioned interface dipole control method and deposition process control method can work together to achieve fine adjustment of the work function of the first ITO layer 21 without significantly increasing structural complexity. This, along with the aforementioned three-layer composite structure of the first ITO layer 21 / Au layer 22 / second ITO layer 23 and its thickness parameter design, creates a synergistic effect, enabling the intermediate layer 20 to form a better electron transport interface on the crystalline silicon bottom cell 10 side. This further reduces the interface resistance and improves the carrier recombination efficiency, ultimately enhancing the overall photoelectric conversion performance of the perovskite / crystalline silicon tandem solar cell 100.

[0050] In a further embodiment, the second ITO layer 23 is modified with chlorine atoms to form an In-Cl dipole or its work function is regulated by adjusting the oxygen flow rate during the deposition process. In this embodiment, the work function is regulated by modifying the interface of the second ITO layer 23 or by controlling the deposition process, thereby further optimizing the energy level matching relationship between the intermediate layer 20 and the hole transport layer 31 of the perovskite top cell 30. Specifically, by introducing chlorine atoms to modify the surface of the second ITO layer 23, a stable In-Cl interface dipole structure can be formed on the surface of the second ITO layer 23. This interface dipole can change the potential distribution on the surface of the second ITO layer 23, thereby increasing the work function of the second ITO layer 23 and stabilizing it in the range of 4.6 eV-4.8 eV. This better matches the energy level structure of the hole transport layer 31, which is beneficial for hole transport from the perovskite top cell 30 to the intermediate layer 20, while reducing the interface barrier and reducing interface carrier recombination losses.

[0051] In this embodiment, by adjusting the oxygen flow rate during the deposition of the second ITO layer 23, the oxygen vacancy concentration and carrier concentration in the ITO film can be controlled, thereby achieving fine adjustment of the work function of the second ITO layer 23. This allows it to maintain good conductivity while forming a more matched energy level structure with the hole transport layer 31. The In-Cl dipole control method formed by the chlorine atom modification and the deposition process control method can achieve stable control of the work function of the second ITO layer 23 without significantly increasing the complexity of the device structure. This works synergistically with the low work function design of the first ITO layer 21 and the thickness parameter design of the three-layer composite structure of the first ITO layer 21 / Au layer 22 / second ITO layer 23, enabling the intermediate layer 20 to form an interface structure on the perovskite side that is more conducive to hole transport and electron-hole recombination. At the same time, it works with the Au layer 22 to construct a stable tunneling recombination path.

[0052] In a further embodiment, the n-type doped silicon-based thin film layer 16 is an n-type doped amorphous silicon layer or an n-type doped nanocrystalline silicon layer. In this embodiment, the n-type doped silicon-based thin film layer 16 in the crystalline silicon bottom cell 10 is set as an n-type doped amorphous silicon layer or an n-type doped nanocrystalline silicon layer, so that the n-type doped silicon-based thin film layer 16 can form a stable electron transport and interface transition structure between the crystalline silicon bottom cell 10 and the intermediate layer 20, thereby further optimizing the electrical coupling relationship between the bottom cell side and the intermediate layer 20. Specifically, the n-type doped amorphous silicon layer has better interface passivation capability, which can effectively reduce the interface defect density on the surface of the crystalline silicon absorber layer, thereby reducing the recombination loss of charge carriers at the interface, and facilitating the transport of electrons from the n-type doped silicon absorber layer 14 to the intermediate layer 20, thereby improving the charge carrier collection efficiency on the bottom cell side. Compared with amorphous silicon, the n-type doped nanocrystalline silicon layer has higher conductivity and better charge carrier transport capability, and can further reduce the interface resistance while ensuring a certain interface passivation effect, thereby improving the efficiency of electron transport to the intermediate layer 20.

[0053] In this embodiment, by selecting the two material forms mentioned above, the n-type doped silicon-based thin film layer 16 can effectively passivate the surface of the crystalline silicon absorber layer and provide a low-resistance transport channel for electrons, thereby forming a stable electron transport interface between the crystalline silicon bottom cell 10 and the intermediate layer 20. Furthermore, the work function design of the n-type doped silicon-based thin film layer 16 and the first ITO layer 21 in the intermediate layer 20 (4.0 eV-4.4 eV) is coordinated, enabling the first ITO layer 21 to form a more matched energy level structure with the n-type doped silicon-based thin film layer 16. This reduces the interface barrier for electrons to enter the intermediate layer 20 from the crystalline silicon bottom cell 10, and together with the Au layer 22 and the second ITO layer 23, constructs an efficient carrier recombination path.

[0054] In a further embodiment, the hole transport layer 31 is made of MeO-2PACz, 4PABCz and its derivatives, PTAA or NiO. x It can form a good hole-selective transport channel and form a good energy level match with the intermediate layer 20, thereby promoting the efficient extraction and transport of holes, while suppressing electron back transport, reducing interface recombination loss, and thus improving the fill factor and photoelectric conversion efficiency of the device.

[0055] In a further embodiment, the thickness of the perovskite absorber layer 32 is any value between 500 nm and 800 nm, that is, the thickness of the perovskite absorber layer 32 can be 500 nm, 600 nm, 700 nm, or 800 nm, or any other value between 500 nm and 800 nm. The thickness of the electron transport layer 33 is any value between 10 nm and 40 nm, and the material is C. 60The thickness of the electron transport layer 33 can be 10nm, 20nm, 30nm, or 40nm, or any other value between 10nm and 40nm. The thickness of the second electrode layer 34 is any value between 80nm and 150nm, and the material is at least one of ITO, AZO, or IZO. The thickness of the second electrode layer 34 can be 80nm, 90nm, 100nm, 110nm, 120nm, 130nm, 140nm, or 150nm, or any other value between 80nm and 150nm. The thickness of the antireflection layer 35 is any value between 80nm and 150nm, and the material is at least one of MgF2, SiO2, or Al2O3. The thickness of the antireflection layer 35 can be 80nm, 90nm, 100nm, 110nm, 120nm, 130nm, 140nm, or 150nm, or any other value between 80nm and 150nm. Through the coordination of the material selection and thickness parameter design of the above-mentioned structural layers, the perovskite top cell 30 achieves a synergistic effect in terms of enhanced light absorption, efficient carrier transport, and reduced optical loss. It also works together with the work function gradient structure of the intermediate layer 20 and the energy level matching relationship of the crystalline silicon bottom cell 10 to further improve the light utilization rate and overall photoelectric conversion efficiency of the perovskite / crystalline silicon tandem solar cell 100.

[0056] In this embodiment, the thickness of the perovskite absorption layer 32 is set in the range of 500nm-800nm. This ensures that the perovskite material fully absorbs photons in the visible light band while avoiding carrier recombination losses due to excessive thickness, thus achieving a balance between light absorption efficiency and carrier transport distance. The thickness of the electron transport layer 33 is set in the range of 10nm-40nm, and C0 is selected. 60 Materials such as PCBM or SnO2, which possess excellent electron transport capabilities and energy level matching characteristics, enable electrons to be efficiently injected from the perovskite absorber layer 32 and transported to the second electrode layer 34, while effectively blocking hole backflow, thereby improving carrier separation and collection efficiency. Furthermore, the thickness of the second electrode layer 34 is set to 80nm-150nm, and transparent conductive oxide materials such as ITO, AZO, or IZO are used to maintain high light transmittance while possessing good lateral conductivity, thus providing a stable current collection channel for carriers. The thickness of the antireflection layer 35 is set to 80nm-150nm, and dielectric materials with suitable refractive indices such as MgF2, SiO2, or Al2O3 are selected, which can effectively reduce the reflection loss of incident light on the device surface and improve the coupling efficiency of light in the perovskite absorber layer 32.

[0057] In a further embodiment, the thickness of the first intrinsic amorphous silicon layer 13 and the second intrinsic amorphous silicon layer 15 is any value between 3nm and 10nm, and the thickness of the p-type doped amorphous silicon layer 12 and the n-type doped silicon-based thin film layer 16 is any value between 5nm and 20nm. That is, the thickness of the first intrinsic amorphous silicon layer 13 and the second intrinsic amorphous silicon layer 15 can be 3nm, 4nm, 5nm, 6nm, 7nm, 8nm, 9nm or 10nm, or any other value between 3nm and 10nm. The thickness of the p-type doped amorphous silicon layer 12 and the n-type doped silicon-based thin film layer 16 can be 5nm, 10nm, 15nm or 20nm, or any other value between 5nm and 20nm. In this embodiment, by synergistically designing the thickness ranges of the first intrinsic amorphous silicon layer 13, the second intrinsic amorphous silicon layer 15, the p-type doped amorphous silicon layer 12, and the n-type doped silicon-based thin film layer 16 in the crystalline silicon bottom cell 10, the bottom cell achieves optimized coordination in terms of interface passivation, selective carrier transport, and electrical connection, thereby improving the electrical coupling performance between the crystalline silicon bottom cell 10 and the intermediate layer 20. Specifically, the thickness of the first intrinsic amorphous silicon layer 13 and the second intrinsic amorphous silicon layer 15 is set in the range of 3nm-10nm, which can form an effective interface passivation layer on the surface of the crystalline silicon absorber layer, thereby reducing the interface defect state density and reducing carrier recombination loss. At the same time, this thickness range can ensure that carriers can still be transported smoothly through tunneling or diffusion, avoiding the introduction of additional transport obstacles due to excessively thick passivation layers. The thickness of the p-type doped amorphous silicon layer 12 is set in the range of 5nm-20nm, which enables it to form a stable hole-selective contact structure, providing effective bandgap regulation while maintaining good conductivity, thereby promoting selective hole transport and suppressing electron backflow. The thickness of the n-type doped silicon-based thin film layer 16 is also set to 5nm-20nm, so that it can provide a good electron transport channel and form a stable interface contact with the upper intermediate layer 20, thereby reducing the interface resistance.

[0058] In a further embodiment, the thickness of the n-type doped silicon absorber layer 14 is any value between 150 μm and 300 μm, that is, the thickness of the n-type doped silicon absorber layer 14 can be 150 μm, 200 μm, 250 μm, or 300 μm, or any other value between 150 μm and 300 μm. In this embodiment, by setting the thickness of the n-type doped silicon absorber layer 14 within the range of 150 μm to 300 μm, a good balance is achieved between the light absorption capacity and the carrier transport efficiency of the crystalline silicon bottom cell 10, thereby improving the photoelectric conversion capability of the bottom cell in the stacked structure. Specifically, when the thickness of the n-type doped silicon absorber layer 14 is within this range, it can be ensured that long-wavelength light (such as the near-infrared band) transmitted through the upper perovskite top cell 30 and the intermediate layer 20 is fully absorbed in the crystalline silicon material, thereby improving the utilization rate of long-wavelength photons by the crystalline silicon bottom cell 10. At the same time, this thickness range can avoid excessively thick silicon layers, which would lead to excessively long carrier diffusion paths, thereby reducing energy loss caused by carrier recombination in the bulk and facilitating the effective separation and collection of photogenerated electrons and holes.

[0059] Furthermore, the aforementioned thickness parameters are coordinated with the interface structure design of the first intrinsic amorphous silicon layer 13, the second intrinsic amorphous silicon layer 15, the p-type doped amorphous silicon layer 12, and the n-type doped silicon-based thin film layer 16 in the crystalline silicon bottom cell 10, so that photogenerated carriers can be efficiently transported from the silicon absorption layer to the interface and selectively extracted. At the same time, it forms a good energy level matching relationship with the work function design of the first ITO layer 21 in the intermediate layer 20, thereby reducing the interface barrier when electrons enter the intermediate layer 20 from the crystalline silicon bottom cell 10.

[0060] In a further embodiment, the thickness of the first electrode layer 11 is any value between 80nm and 150nm, and the material is Ag, Al, or Ag / Al composite metal. That is, the thickness of the first electrode layer 11 can be 80nm, 90nm, 100nm, 110nm, 120nm, 130nm, 140nm, or 150nm, or any other value between 80nm and 150nm. In this embodiment, setting the thickness of the first electrode layer 11 to the range of 80nm-150nm and selecting Ag, Al, or Ag / Al composite metal as the electrode material allows the electrode layer to provide a stable current collection channel while ensuring a low sheet resistance. This facilitates the rapid extraction of photogenerated carriers in the crystalline silicon bottom cell 10 and reduces energy loss caused by series resistance. Meanwhile, Ag or Al metals have high light reflectivity. When their thickness is within the above range, they can form an effective reflective interface at the bottom of the device, so that long-wavelength light that is not completely absorbed by the crystalline silicon absorption layer is reflected at the bottom and re-enters the silicon absorption layer for secondary absorption, thereby improving the utilization rate of incident light by the crystalline silicon bottom cell 10.

[0061] Furthermore, the Ag / Al composite metal structure can combine the advantages of Ag's high conductivity and Al's good adhesion, thereby improving the interface stability between the electrode layer and adjacent functional layers while maintaining low resistance, thus improving the reliability of the device in long-term operation.

[0062] In this embodiment, as the thickness of the device changes from bottom to top, the work function, band gap, and doping type of each functional layer material are different, which makes its conduction band and valence band exhibit partitioned and gradient distribution characteristics in space, thereby forming a band structure that is conducive to carrier separation, transport, and recombination.

[0063] The technical solution of this application will be further described below with reference to specific embodiments.

[0064] Example 1

[0065] The perovskite / crystalline silicon tandem solar cell 100 includes a crystalline silicon bottom cell 10, an intermediate layer 20, and a perovskite top cell 30 stacked from bottom to top. The crystalline silicon bottom cell 10 includes a first electrode layer 11, a p-type doped amorphous silicon layer 12, a first intrinsic amorphous silicon layer 13, an n-type doped silicon absorber layer 14, a second intrinsic amorphous silicon layer 15, and an n-type doped silicon-based thin film layer 16 stacked from bottom to top. The perovskite top cell 30 includes a hole transport layer 31, a perovskite absorber layer 32, an electron transport layer 33, a second electrode layer 34, and an antireflection layer 35 stacked from bottom to top. The intermediate layer 20 is located between the hole transport layer 31 and the n-type doped silicon-based thin film layer 35. Between the thin film layers 16, there are a first ITO layer 21, an Au layer 22, and a second ITO layer 23 sequentially disposed along the direction away from the n-type doped silicon-based thin film layer 16 to the hole transport layer 31; wherein the thickness of the first ITO layer 21 and the second ITO layer 23 is 2.5 nm, the thickness of the Au layer 22 is 1.5 nm, the work function of the first ITO layer 21 is 4.3 eV, and the work function of the second ITO layer 23 is 4.7 eV, so that the intermediate layer 20 forms an energy level match with the crystalline silicon bottom cell 10 and the hole transport layer 31 respectively, and a tunneling structure 60 is formed between the hole transport layer 31, the second ITO layer 23, and the Au layer 22.

[0066] Comparative Example 1

[0067] The only difference between Comparative Example 1 and Example 1 is that the intermediate layer 20 is a single-layer first ITO layer 21.

[0068] Comparative Example 2

[0069] The only difference between Comparative Example 2 and Example 1 is that the intermediate layer 20 includes only the first ITO layer 21 and the Au layer 22.

[0070] Comparative Example 3

[0071] The only difference between Comparative Example 3 and Example 1 is that the intermediate layer 20 only includes an Au layer 22 and a second ITO layer 23.

[0072] Comparative Example 4

[0073] The only difference between Comparative Example 4 and Example 1 is that the intermediate layer 20 is a third ITO layer, an Au layer 22, and a fourth ITO layer. The work function of the third ITO layer and the fourth ITO layer is the same, which is 4.3 eV.

[0074] Comparative Example 5

[0075] The only difference between Comparative Example 5 and Example 1 is that the intermediate layer 20 is a third ITO layer, an Au layer 22, and a fourth ITO layer. The work function of the third ITO layer and the fourth ITO layer is the same, which is 4.7 eV.

[0076] Figure 3 This is a schematic performance band structure diagram of a perovskite / crystalline silicon tandem solar cell according to Comparative Example 1 of the present invention. Figure 4 This is a schematic performance band structure diagram of a perovskite / crystalline silicon tandem solar cell according to Comparative Example 1 of the present invention.

[0077] like Figure 3 As shown, in the perovskite / crystalline silicon tandem solar cell 100 of Example 1, by setting the first ITO layer 21, Au layer 22 and the second ITO layer 23 in the intermediate layer 20 to be controlled by gradient work function, the energy levels of the conduction band and valence band of the intermediate layer 20 are close to the energy levels of the upper and lower layers, thereby achieving good band matching, reducing the interface barrier, and enabling electrons of the crystalline silicon bottom cell 10 and holes of the perovskite top cell 30 to migrate to the intermediate layer 20 for recombination. Furthermore, the tunneling structure 60 formed between the second ITO layer 23, Au layer 22 and hole transport layer 31 of the intermediate layer 20 further improves the hole migration effect and improves the photoelectric conversion efficiency of the perovskite / crystalline silicon tandem solar cell 100.

[0078] like Figure 4 As shown, in the perovskite / crystalline silicon tandem solar cell 100 of Comparative Example 1, the intermediate layer 20 is a single-layer ITO layer with the same thickness as the intermediate layer 20 in Example 1. The single-layer ITO has a single work function, which results in a large energy difference between the conduction band and valence band energy levels of the intermediate layer 20 and the energy levels of the upper and lower layers, forming a large interface barrier. As a result, the presence of the intermediate layer 20 cannot achieve band matching with the perovskite top cell 30 and the crystalline silicon bottom cell 10.

[0079] Figure 5 These are current-voltage curves of perovskite / crystalline silicon tandem solar cells according to Embodiment 1 and Comparative Example 1 of the present invention. Figure 6 These are current-voltage curves of perovskite / crystalline silicon tandem solar cells according to Embodiment 1 and Comparative Examples 2-3 of the present invention. Figure 7 The figures are current-voltage curves of perovskite / crystalline silicon tandem solar cells according to Embodiment 1 and Comparative Examples 4-5 of the present invention.

[0080] The electrical and optical performance of the perovskite / crystalline silicon tandem solar cells 100 in Example 1 and Comparative Examples 1-5 were tested respectively, and the results are shown in Table 1 and Table 2. Figure 5-7 The test results are shown.

[0081] Table 1. Performance test results of perovskite / crystalline silicon tandem solar cells in Example 1 and Comparative Examples 1-5

[0082]

[0083] As shown in Table 1 and Figure 5-7 As shown, the perovskite / crystalline silicon tandem solar cell 100 in Example 1 has a significantly higher fill factor and photoelectric conversion efficiency than Comparative Examples 1-5. Specifically, the intermediate layer 20 adopts a three-layer structure of a first ITO layer 21 / Au layer 22 / second ITO layer 23, and forms a gradient energy level structure by setting different work functions (4.3eV and 4.7eV), so that the intermediate layer 20 achieves good energy level matching with the crystalline silicon bottom cell 10 and the hole transport layer 31, respectively. At the same time, a tunneling structure 60 is formed between the hole transport layer 31, the second ITO layer 23 and the Au layer 22, thereby effectively promoting the recombination of electrons and holes at the intermediate layer 20 and reducing the interface transport barrier. Therefore, the device exhibits the highest fill factor (87.3%) and photoelectric conversion efficiency (32.9%).

[0084] In contrast, Comparative Example 1 uses only a single layer of indium tin oxide (ITO) as the intermediate layer 20, lacking effective carrier recombination channels and energy level control capabilities, resulting in a decrease in its fill factor and efficiency to 84.9% and 32.09%, respectively. Comparative Examples 2 and 3 suffer from incomplete intermediate layer 20 structures. Comparative Example 2 lacks an ITO layer near the hole transport layer 31, leading to insufficient interface energy level matching and a significant reduction in carrier recombination efficiency, causing a substantial drop in fill factor and efficiency to 72.65% and 26.68%, respectively. Comparative Example 3 lacks an ITO layer near the crystalline silicon bottom cell 10; although some recombination channels can still be formed, the overall transport efficiency is reduced. Furthermore, in Comparative Examples 4 and 5, although the intermediate layer 20 also adopts the ITO / Au / ITO structure, the work functions of the two ITO layers are the same (both 4.3eV or 4.7eV), which cannot simultaneously take into account the energy level matching between the perovskite top cell 30 and the crystalline silicon bottom cell 10. Therefore, their fill factor and efficiency are lower than those of Example 1.

[0085] In summary, by introducing ITO / Au / ITO structures with different work functions into the intermediate layer 20, better band matching and tunnel recombination can be achieved, thereby significantly improving the overall performance of the perovskite / crystalline silicon tandem solar cell 100.

[0086] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0087] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A perovskite / crystalline silicon tandem solar cell, characterized in that, The system comprises a crystalline silicon bottom cell, an intermediate layer, and a perovskite top cell stacked from bottom to top. Along the bottom-to-top direction, the crystalline silicon bottom cell includes a first electrode layer, a p-type doped amorphous silicon layer, a first intrinsic amorphous silicon layer, an n-type doped silicon absorber layer, a second intrinsic amorphous silicon layer, and an n-type doped silicon-based thin film layer stacked sequentially. The intermediate layer includes a first ITO layer, an Au layer, and a second ITO layer stacked sequentially. The perovskite top cell includes a hole transport layer, a perovskite absorber layer, an electron transport layer, a second electrode layer, and an antireflection layer stacked sequentially. The work function of the first ITO layer is any value between 4.0 eV and 4.4 eV, and the work function of the second ITO layer is any value between 4.6 eV and 4.8 eV, so that the intermediate layer forms an energy level match with the crystalline silicon bottom cell and the hole transport layer respectively, and a tunneling structure is formed between the hole transport layer, the second ITO layer and the Au layer.

2. The perovskite / crystalline silicon tandem solar cell according to claim 1, characterized in that, The thickness of the first ITO layer and the second ITO layer is any value between 2.5nm and 3.0nm, and the thickness of the Au layer is any value between 0.5nm and 2.0nm.

3. The perovskite / crystalline silicon tandem solar cell according to claim 2, characterized in that, The first ITO layer is modified by introducing a nitrogen-containing polymer to form a surface dipole or by adjusting the oxygen flow rate during the deposition process to control the work function.

4. The perovskite / crystalline silicon tandem solar cell according to claim 3, characterized in that, The second ITO layer is modified by chlorine atoms to form an In-Cl dipole or by adjusting the oxygen flow rate during the deposition process to control the work function.

5. The perovskite / crystalline silicon tandem solar cell according to claim 4, characterized in that, The n-type doped silicon-based thin film layer is an n-type doped amorphous silicon layer or an n-type doped nanocrystalline silicon layer.

6. The perovskite / crystalline silicon tandem solar cell according to claim 5, characterized in that, The hole transport layer is made of MeO-2PACz, 4PABCz and its derivatives, PTAA or NiO. x .

7. The perovskite / crystalline silicon tandem solar cell according to any one of claims 1-6, characterized in that, The thickness of the perovskite absorber layer is any value between 500 nm and 800 nm; The thickness of the electron transport layer is any value between 10nm and 40nm, and the material is C. 60 At least one of PCBM or SnO2; The thickness of the second electrode layer is any value between 80nm and 150nm, and the material is at least one of ITO, AZO or IZO; The thickness of the antireflection layer is any value between 80nm and 150nm, and the material is at least one of MgF2, SiO2, or Al2O3.

8. The perovskite / crystalline silicon tandem solar cell according to claim 7, characterized in that, The thicknesses of the first intrinsic amorphous silicon layer and the second intrinsic amorphous silicon layer are both any value between 3nm and 10nm, and the thicknesses of the p-type doped amorphous silicon layer and the n-type doped silicon-based thin film layer are both any value between 5nm and 20nm.

9. The perovskite / crystalline silicon tandem solar cell according to claim 8, characterized in that, The thickness of the n-type doped silicon absorber layer is any value between 150 μm and 300 μm.

10. The perovskite / crystalline silicon tandem solar cell according to claim 9, characterized in that, The thickness of the first electrode layer is any value between 80nm and 150nm, and the material is Ag, Al, or Ag / Al composite metal.

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