Hybrid multiband photovoltaic cell and preparation method thereof

Abstract

The invention discloses a hybrid multiband photovoltaic cell and a preparation method thereof. The cell main body comprises a perovskite / organic series laminated cell structure, a multi-junction gallium arsenide cell structure and an antimony-based infrared photovoltaic cell structure which are arranged side by side and separated by insulating layers. The multi-junction gallium arsenide cell structure comprises a plurality of sub-cell units which are stacked in sequence and connected in series through tunnel junctions. The sub-cell units are made of gallium arsenide-based materials with different band gaps. The invention provides a hybrid multiband photovoltaic cell. A multijunction gallium arsenide cell structure, an antimony-based infrared photovoltaic cell structure, a perovskite / organic series laminated cell structure, a transmission-type three-channel micro-nano grating device with a connecting layer and the like are integrated. By optimizing material selection, structural design and multi-type combination, the three main wavebands of ultraviolet light, visible light and infrared light of sunlight are better adapted, the photoelectric conversion efficiency is greatly improved, and the process complexity is reduced. Therefore, the method has remarkable economic, social and environmental benefits.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cells, and in particular to a multi-junction gallium arsenide cell structure that is adapted to different spectra of sunlight by compounding three different types of cell structures to improve the photoelectric conversion efficiency of solar cells. Background Art

[0002] With the increasing demand for new energy and heightened awareness of environmental protection, solar cells have received widespread attention as a clean energy conversion device. Gallium arsenide, as an important semiconductor material, has high photoelectric conversion efficiency, good stability, and radiation resistance, making it an ideal choice for making high-efficiency solar cells. By stacking multiple cell layers with different band gaps, multi-junction gallium arsenide cells can broaden the spectral response range, improve the utilization of sunlight, and thus enhance the conversion efficiency of the cell. Although multi-junction solar cells can effectively utilize and absorb the visible light band of sunlight, due to the wide frequency domain of the sunlight spectrum, covering the three main bands of ultraviolet light, visible light, and infrared light, it is difficult to use a single type of cell structure to adapt to these three main bands, thus affecting the further increase of photoelectric conversion efficiency. Therefore, it is necessary to develop an optimized hybrid multi-band photovoltaic cell, which is of great significance for improving the efficiency and performance of solar cells. Summary of the Invention

[0003] The purpose of the present invention is to provide a hybrid multi-band photovoltaic cell that, by optimizing material selection, structural design and multi-type combination, can better adapt to the three main bands of sunlight: ultraviolet light, visible light and infrared light, improve photoelectric conversion efficiency, and reduce process complexity.

[0004] In a first aspect, the present invention provides a hybrid multi-band photovoltaic cell comprising a cell body comprising a perovskite / organic tandem stacked cell structure, a multi-junction gallium arsenide cell structure, and an antimony-based infrared photovoltaic cell structure, arranged side by side and separated by an insulating layer.

[0005] The perovskite / organic tandem stack cell structure includes a stacked wide-bandgap front-stage cell and a narrow-bandgap back-stage cell. A carrier recombination layer is provided between the wide-bandgap front-stage cell and the narrow-bandgap back-stage cell. The wide-bandgap front-stage cell uses perovskite as a light-absorbing layer. The narrow-bandgap back-stage cell uses an organic photovoltaic material as a light-absorbing layer. The wide-bandgap front-stage cell absorbs high-energy photons and converts them into electrical energy. The narrow-bandgap back-stage cell primarily absorbs low-energy photons that pass through the perovskite and are not utilized. The carrier recombination layer connects the wide-bandgap front-stage cell and the narrow-bandgap back-stage cell in series and facilitates carrier recombination. Because the wide-bandgap front-stage cell and the narrow-bandgap back-stage cell are connected in series in a circuit, under ideal conditions, the open-circuit voltage of the stack is equal to the sum of the voltages of the wide-bandgap front-stage cell and the narrow-bandgap back-stage cell.

[0006] The multi-junction GaAs cell structure comprises multiple sub-cells stacked in sequence and connected in series via tunnel junctions. Each sub-cell uses GaAs-based materials with different band gaps. The tunnel junctions are made of highly doped semiconductor materials to achieve a low-resistance connection.

[0007] The antimony-based infrared photovoltaic cell structure includes a top subcell and a bottom subcell stacked in sequence and connected in series via a tunnel junction. The top subcell is constructed based on GaInAsSb; the bottom subcell is constructed based on InAsSb material. The antimony-based infrared photovoltaic cell structure adopts the structure of a GaInAsSb / InAsSb stacked cell. Both the top subcell and the bottom subcell adopt an NP-type, two-terminal output device, and the two subcells are connected by an ideal tunnel junction. At a given radiation temperature, high-energy photons are mainly absorbed by the top subcell, while photons with lower energy but above 0.286 eV will pass through the top subcell and be absorbed by the bottom subcell.

[0008] Preferably, the wide bandgap front-stage cell and the narrow bandgap rear-stage cell both include an electron transport layer, a perovskite layer and a hole transport layer.

[0009] Preferably, the perovskite material in the wide bandgap front-stage cell is CsPbI2Br. The organic photovoltaic material perovskite layer in the narrow bandgap back-stage cell is a bulk heterojunction of a mixed material of PTB7-Th and PM6.

[0010] Preferably, the multi-junction gallium arsenide cell structure also includes an anti-reflection layer and an electrode layer. The anti-reflection layer is used to reduce light reflection losses, and the electrode layer is used to collect and conduct photogenerated current. By stacking multiple semiconductor materials with different band gaps, segmented absorption of the solar spectrum is achieved, significantly improving conversion efficiency.

[0011] Preferably, the number of sub-cell units in the multi-junction gallium arsenide cell structure is three. The three sub-cell units are a top sub-cell, a middle sub-cell, and a bottom sub-cell, each including a window layer, an emitter region, a base region, and a back electric field layer. The materials of the window layer, emitter region, base region, and back electric field layer in the top sub-cell are n-AlInP, n-GaInP, p-GaInP, and p-AlGaInP, respectively. The materials of the window layer, emitter region, base region, and back electric field layer in the middle sub-cell are n-GaInP, n-InGaAs, p-InGaAs, and p-AlGaAs, respectively. The materials of the window layer, emitter region, base region, and back electric field layer in the bottom sub-cell are n-GaAs, n-Ge, p-Ge, and p-Ge, respectively.

[0012] Preferably, the top and bottom subcells in the antimony-based infrared photovoltaic cell structure each include an emitter region and a base region. The emitter region and base region materials of the top subcell are N-GaInAsSb and P-GaInAsSb, respectively. The emitter region and base region materials of the bottom subcell are N-InAsSb and P-InAsSb, respectively.

[0013] Preferably, the device further includes a transmissive three-channel micro-nano grating device covering the light-incoming side of the cell body. The transmissive three-channel micro-nano grating device comprises a grating body and a connecting layer covering the side of the grating body closest to the cell body. The grating body is made of silicon dioxide. The medium in the grating grooves of the grating body is air. The connecting layer is made of tantalum pentoxide. The grating period of the grating body is 1000 nm to 1100 nm.

[0014] In a second aspect, the present invention provides a preparation method for preparing the aforementioned hybrid multi-band photovoltaic cell. The preparation method comprises: Fabrication of a multi-junction GaAs cell structure: First, n-type doping is performed on a p-doped Ge substrate to form the emitter region of the bottom subcell. Two-dimensional nucleation is then performed on the step, followed by the growth of a buffer layer. Continued epitaxial growth forms the middle subcell, the top subcell, and the tunnel junction separating the subcells.

[0015] Preparation of antimony-based infrared photovoltaic cell structure: epitaxial growth on the substrate to form bottom sub-cell and top sub-cell.

[0016] Preparation of perovskite / organic tandem stacked cell structure: a wide bandgap front-stage cell, a carrier recombination layer and a narrow bandgap back-stage cell are formed in sequence by layer-by-layer spin coating.

[0017] The multi-junction gallium arsenide cell structure, the antimony-based infrared photovoltaic cell structure, and the perovskite / organic series stacked cell structure are arranged side by side in sequence, and adjacent cell structures are separated by an insulating separation layer.

[0018] Preferably, the MO source for the epitaxial growth of the multi-junction gallium arsenide cell structure is one or more of trimethyl gallium, trimethyl aluminum, and trimethyl indium, the doping source is one or more of disilane, diethyl antimony, dimethyl zinc, and carbon tetrabromide, the special gas is one or more of arsine and phosphine, and hydrogen is used as the carrier gas.

[0019] Preferably, in the process of preparing the perovskite / organic tandem stacked cell structure, an 85-95 nm ZnO layer is spin-coated, which serves as an interconnection layer between the carrier recombination layer and the narrow bandgap subsequent cell, as well as an electron transport layer for the narrow bandgap subsequent cell.

[0020] The present invention has the following beneficial effects: The present invention provides a hybrid multi-band photovoltaic cell that integrates a multi-junction gallium arsenide cell structure, an antimony-based infrared photovoltaic cell structure, a perovskite / organic tandem cell structure, and a transmissive three-channel micro-nano grating device with a connecting layer. By optimizing material selection, structural design, and multi-type combination, the cell better adapts to sunlight's three main wavelengths: ultraviolet, visible, and infrared. This significantly improves photoelectric conversion efficiency and reduces process complexity. Consequently, it offers significant economic, social, and environmental benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is an overall schematic diagram of Example 1 of the present invention.

[0022] Figure 2 Schematic diagram of the perovskite / organic tandem stacked cell structure in Example 1 of the present invention.

[0023] Figure 3 Schematic diagram of the multi-junction gallium arsenide cell structure in Example 1 of the present invention.

[0024] Figure 4 Schematic diagram of the antimony-based infrared photovoltaic cell structure in Example 1 of the present invention.

[0025] Figure 5 Schematic diagram of the structure of the transmissive three-channel micro-nano grating device in Example 1 of the present invention. DETAILED DESCRIPTION

[0026] The present invention will be further described below with reference to the accompanying drawings.

[0027] Example 1 like Figure 1 As shown, a hybrid multi-band photovoltaic cell includes a cell body. The cell body comprises a perovskite / organic tandem stacked cell structure 1, a first insulating separator layer 2, a multi-junction gallium arsenide cell structure 3, a second insulating separator layer 4, and an antimony-based infrared photovoltaic cell structure 5, arranged alternately in sequence, forming a hybrid high-efficiency photovoltaic cell. The first insulating separator layer 2 and the second insulating separator layer 4 are used to separate the different cell structures.

[0028] like Figure 2 As shown, the perovskite / organic tandem stacked cell structure 1 includes a first electrode 1-2, a first ohmic contact layer 1-3, a first anti-reflection film 1-1, a first electron transport layer (ETL) 1-4, a wide bandgap perovskite layer 1-5, a first hole transport layer (HTL) 1-6, a carrier recombination layer 1-7, a second electron transport layer (ETL) 1-8, a narrow bandgap organic photovoltaic material layer 1-9, a second hole transport layer (HTL) 1-10, a transparent conductive oxide (ITO) 1-11 and a second electrode 1-12 stacked in sequence.

[0029] The first electron transport layers (ETLs) 1-4, wide-bandgap perovskite layers 1-5, and first hole transport layers (HTLs) 1-6 form a wide-bandgap front-stage cell. The second electron transport layers (ETLs) 1-8, narrow-bandgap organic photovoltaic material layers 1-9, and second hole transport layers (HTLs) 1-10 form a narrow-bandgap back-stage cell.

[0030] This example integrates a wide-bandgap perovskite device with a narrow-bandgap organic bulk heterojunction cell to fabricate a high-efficiency tandem perovskite / organic tandem solar cell structure. In this example, CsPbI2Br perovskite material is used as the front wide-bandgap perovskite layers 1-5, a ZnO / Ag(2nm) / MoO3 multilayer is used as the middle carrier recombination layer 1-7, and PM6:Y6 and PTB7-Th:O6T-4F are used as the back narrow-bandgap organic photovoltaic material layers 1-9.

[0031] like Figure 3 As shown, the multi-junction gallium arsenide cell structure 3 includes a third electrode 3-1, a second ohmic contact layer 3-2, a second anti-reflection film 3-3, an n-AlInP window layer 3-4, an n-GaInP emitter region 3-5, a p-GaInP base region 3-6, a p-AlGaInP back electric field layer 3-7, a first p++ tunnel junction layer 3-8, a first n++ tunnel junction layer 3-9, an n-GaInP window layer 3-10, an n-InGaAs emitter region 3-11, a p-InGaAs base region 3-12, a p-AlGaAs back electric field layer 3-13, a second p++ tunnel junction layer 3-14, a second n++ tunnel junction layer 3-15, an n-GaAs buffer region 3-16, an n-Ge emitter region 3-17, a p-Ge base 3-18, a p-Ge substrate 3-19, and a fourth electrode 3-20.

[0032] The top subcell, with a bandgap of 1.90 eV, consists of an n-AlInP window layer 3-4, an n-GaInP emitter region 3-5, a p-GaInP base region 3-6, and a p-AlGaInP back field layer 3-7. The middle subcell, with a bandgap of 1.41 eV, is comprised of an n-GaInP window layer 3-10, an n-InGaAs emitter region 3-11, a p-InGaAs base region 3-12, and a p-AlGaAs back field layer 3-13. The bottom subcell, with a bandgap of 0.67 eV, consists of an n-GaAs buffer region 3-16, an n-Ge emitter region 3-17, a p-Ge base region 3-18, and a p-Ge substrate 3-19. The three subcells are connected in series by providing a tunnel junction between adjacent subcells.

[0033] The multi-junction gallium arsenide cell structure is a superposition of three sub-cells connected in series through a tunnel junction. The essence of its chip production is to make electrodes for the epitaxial wafer, so metal evaporation is required on the front and back of the epitaxial wafer. In addition, in order to ensure good ohmic contact of the front electrode, a layer of highly doped capping material needs to be grown on the top during epitaxial growth. The role of capping layer corrosion is to remove the capping material not covered by the metal electrode. Capping layer corrosion reduces the light absorption of useless capping material. The role of the anti-reflection film is to reduce the waste of light resources caused by reflection on the cell surface and increase the cell's absorption of sunlight. The purpose of the front electrode photolithography process in chip production is to produce the grid line layout of the cell, while the role of other photolithography is to protect the cell from being affected by the subsequent process. Another epitaxial wafer can be used to make multiple solar cells. The purpose of the mesa corrosion is to divide the epitaxial wafer, and finally a dicing machine can be used to cut it to obtain individual solar cells.

[0034] The production process for multi-junction GaAs cell structures includes photolithography, etching, vapor deposition, alloying, and coating. The photolithography process includes front electrode lithography, cap layer lithography, mesa lithography, and coating lithography. The etching process uses chemical etching, employing different etching solutions tailored to the characteristics of mesa and cap layer corrosion to achieve the desired etching effect. The positive and back electrodes of the cell are deposited using different electrode materials, combining the characteristics of electron beam evaporation deposition and the properties of the metal and epitaxial materials. These materials are then alloyed in an annealing furnace at the appropriate temperature and method to achieve good ohmic contact between the electrode and the epitaxial material. Finally, ion source-assisted coating technology and sputtering are used to vapor-deposit a double-layer anti-reflection film of TO2 / AbO3 on the cell surface, reducing wasteful light reflection from the cell surface and significantly improving cell performance.

[0035] like Figure 4 As shown, the antimony-based infrared photovoltaic cell structure 5 includes a fifth electrode 5-1, a third ohmic contact layer 5-2, a third antireflection film 5-3, and a sequentially stacked N-GaInAsSb emitter region 5-4, a P-GaInAsSb base region 5-5, a tunnel junction 5-6, an N-InAsSb emitter region 5-7, a P-InAsSb base region 5-8, a GaSb substrate 5-9, and a sixth electrode 5-10. The N-GaInAsSb emitter region 5-4 and the P-GaInAsSb base region 5-5 constitute the top cell, while the N-InAsSb emitter region 5-7 and the P-InAsSb base region 5-8 constitute the bottom cell. The top and bottom cells are connected via a tunnel junction 5-6.

[0036] The doping concentration of the N-GaInAsSb emitter region 5-4 is (9-10)×10E+l7 cm -3 The doping concentration of the P-GaInAsSb base region 5-5 is (3.5-4)×10E+l7 cm-3 The doping concentration of N-InAsSb emitter region 5-7 is 10×10E+l7 cm -3 The doping concentration of the P-InAsSb base region 5-8 is 1×10E+l7 cm -3 The thickness of the N-GaInAsSb emitter region 5-4 is 0.2 μm, and the thickness of the P-GaInAsSb base region 5-5 is 7-8.5 μm; the thickness of the N-InAsSb emitter region 5-7 is 0.1 μm, and the thickness of the P-InAsSb base region 5-8 is 1.4-1.8 μm.

[0037] In some embodiments, the hybrid multi-band photovoltaic cell further includes a transmissive three-channel micro-nano grating device 6 with a connecting layer covering the light-incoming side of the cell body. The sunlight is split by the transmissive three-channel micro-nano grating device 6 into approximately three wavelengths: infrared, visible, and ultraviolet. These wavelengths are then projected onto the three corresponding cell structures, maximizing photovoltaic conversion efficiency.

[0038] In some embodiments, as Figure 5 As shown, the transmissive three-channel micro-nano grating device 6 comprises a grating body and a connecting layer covering the side of the grating body closest to the cell body. The grating grooves, arranged in a rectangular pattern with a period of d, a groove width (i.e., ridge width) of b, a groove height of hg, and a distance from the connecting layer of hc. The medium within the grating grooves is air with a refractive index of n1; the medium outside the grating grooves in the grating body is silicon dioxide with a refractive index of n2; and the connecting layer is Ta2O5 with a refractive index of n3. During operation, sunlight (incident light) is incident vertically and, after passing through the transmissive three-channel micro-nano grating device 6, the outgoing light is split into three wavelength bands: infrared, visible, and ultraviolet. These dimensional parameters are calculated and experimentally derived based on the requirements of hybrid multi-band photovoltaic cells and the rigorous coupled wave analysis optimization method. The grating body has a grating period of d = 1000-1100 nm, a refractive index of n1 = 1.0, a refractive index of n2 = 1.45, and a refractive index of n3 = 2.0. Based on the requirements of hybrid multi-band photovoltaic cells and rigorous coupled wave analysis optimization methods, calculations and experiments were performed. With an incident wavelength of 800 nm, a duty cycle of 0.6, and a grating period of 1090 nm, the optimized grating parameters hg = 0.8 μm and hc = 1.7 μm were obtained.

[0039] In some embodiments, a transmissive three-channel micro-nano grating device realizes a three-channel beam splitting output under the condition of vertical incidence of a plane light wave. The three diffraction orders of the output are -1 order, 0 order and 1 order respectively. Due to the symmetry of the incident light and the structural symmetry of the rectangular grating, the energy of -1 order and the energy of 1 order are the same in these three orders. Therefore, if the energy of the three diffraction orders is to be evenly distributed, it is only necessary to satisfy that the ratio of the diffraction efficiency of 1 order to the diffraction efficiency of 0 order is close to 1. The function of the connecting layer is to connect the micro-nano grating layer with the battery layer. Sunlight is split by the micro-nano grating device to approximately form three bands of infrared light, visible light and ultraviolet light, which are projected onto three corresponding batteries respectively, thereby maximizing the photovoltaic conversion efficiency.

[0040] In some other embodiments, a light-guiding layer is provided between the transmissive three-channel micro-nano grating device and the cell body. The light-guiding layer is used to guide infrared light to the location of the antimony-based infrared photovoltaic cell structure, to guide visible light to the location of the multi-junction gallium arsenide cell junction, and to guide ultraviolet light to the location of the perovskite / organic tandem stacked cell structure, thereby further improving photovoltaic conversion efficiency.

[0041] Example 2 A method for preparing and integrating a hybrid multi-band photovoltaic cell comprises the following steps: Step 1: Prepare a multi-junction GaAs cell structure.

[0042] Excluding the chip's positive and back electrodes, anti-reflection film layer, Ge substrate, and P-diffused emitter layer, there are 15 epitaxial layers, including the nucleation layer, buffer layer, back field layer of the middle and top sub-cells, base region, emitter region, window layer, two tunnel junctions connecting the three sub-cells, and contact layer. Their thickness and structure are shown in Table 1 below.

[0043] Table 1 Materials, functions and thickness of multi-junction GaAs cell structures The first step is to prepare a Ge bottom sub-cell and grow a 0.01 μm thick nucleation layer of GaInP material; perform n-type doping on the p-doped Ge substrate to form an emission region of the n-doped Ge bottom sub-cell.

[0044] Then, epitaxial growth is carried out. The first step of epitaxial growth is surface nucleation, the purpose of which is to allow the polar GaInP material to nucleate in two dimensions on the steps of the non-polar Ge substrate surface, maintaining the step flow growth of the polar material above. It can be seen that growing a high-quality nucleation layer is crucial. The buffer layer GaInAs is grown next. Its purpose is to isolate the bottom sub-cell from the middle sub-cell, preventing Ge from diffusing into the middle sub-cell to form n-type doping, affecting the back field layer and base region of the middle sub-cell; second, to form a good growth interface, transitionally buffering defects such as dislocations existing at the interface between the Ge substrate and the epitaxial growth, and improving the quality of the epitaxially grown material above; third, to suppress the formation of GaAs anti-phase grain boundaries, i.e., anti-phase domains, and prevent the formation of recombination centers in the middle sub-cell material due to anti-phase grain boundaries.

[0045] The tunnel junction connects the subcells in series, preventing direct connection between them, which would cause the pn junction to reverse bias and cancel each other out. The tunnel junction must provide a high peak tunneling current and good light transmittance without affecting the absorption of the underlying cell material. Here, an n-GaAs / p-AlGaAs tunnel junction is used.

[0046] The structure of the middle subcell is essentially the same as that of the top subcell. The back field layer primarily reflects minority carriers generated at the bottom of the base region, allowing them to be effectively collected by the space charge region. Furthermore, the back field layer reduces the surface states of the base emitter region, reducing the recombination of photogenerated carriers at the interface. The back field layer material should have a higher band gap than the base material, resulting in a larger energy difference between their conduction bands and more effective reflection of minority carriers. Furthermore, it requires a higher doping level and a thinner thickness, generally between (0.8-1.2)×10 18 / cm 3 , with a thickness of about 190-210nm to reduce the increase in the series resistance of the battery. In this embodiment, the top sub-cell is made of AlGaInP material, and the middle sub-cell is made of GaInP material. The base and emitter regions of the middle and top sub-cells are the absorption layers of the battery. The most relevant parameters are the band gap, thickness and doping of the material. The band gap of the material determines the absorption cutoff wavelength of the material, the thickness determines the number of carriers generated by the material, and the doping determines the minority carrier lifetime and diffusion length. Here, a p-type emitter region is selected, and the doping is (0.8-1.2)×10 18 / cm 3 , n-type base region, doping adopts field-assisted effect, from the lower layer of the base region upward from (0.8-1.2)×10 18 / cm 3 Transition to (0.8-1.2)×10 16 / cm 3 The material thickness is determined by the material absorption coefficient and current matching.

[0047] The window layer functions similarly to the back field layer. A material with a wider bandgap than the cell's emitter region is selected to form a higher potential barrier, reflecting minority carriers toward the window layer and reducing the surface recombination rate in the emitter region. Furthermore, the window layer must consider light absorption. Using a wider bandgap reduces light absorption, thereby reducing energy loss. It is particularly important to note that the refractive index and thickness of the top sub-cell's window layer also affect the reflectivity of the anti-reflection coating. Here, AlGaAs is selected as the window layer for the middle sub-cell, and AlInP is selected as the top sub-cell's material.

[0048] The MO sources for epitaxial growth of multi-junction GaAs cell structure 3 are mainly trimethylgallium (TMGa), trimethylaluminum (TMAl), and trimethylindium (TMIn). The doping sources are mainly disilane (SiH6), diethylantimony (DETe), dimethylzinc (DMZn), and carbon tetrabromide (CBr4). The specialty gases are arsine (AsH3) and phosphine (PH3). Hydrogen (H2) is used as the carrier gas. The substrate is 4-inch p-type Ge, doped with (4-6)×10 17 / cm 3 , thickness 130-160μm, surface (100) <111> 6°. The growth machine is MOCVD. The epitaxial growth parameters are shown in the table below.

[0049] Epitaxial growth parameters At the beginning of the growth process, a high-temperature treatment of 7-9 minutes is first required, with a temperature of 700-720°C and PH3 protection. The purpose is to remove the high-temperature oxide layer and repair the substrate surface. In addition, when growing the nucleation layer, a V / III ratio of 360-395 is used. The purpose is to grow high-quality materials and inhibit the formation of antiphase grain boundaries. During the epitaxial growth process, when there is an arsenic-phosphorus material interface, the reactive V group gas is generally cut in 2-4s in advance to purge the original V group gas to prevent the growth of arsenic-phosphorus compounds when the two coexist. The tunnel junctions used in the battery are all n++GaAs / p++AlGaAs structures. Both materials require very high doping concentrations and very thin thicknesses. According to the doping rules of the materials, GaAs uses a low-speed Te and Si co-doping method with a doping concentration greater than 1.8-2.2E19cm 3 AlGaAs is doped with C at a low rate, a V / III ratio of 1.8-2.2, and a doping concentration of 0.8-1.2E20cm 3 The entire tunnel junction is grown at a low temperature of 540-560°C to maximize doping concentration. The base and emitter regions of the battery's middle and top subcells utilize the field-assisted effect, with both gradual and sudden doping methods creating varying potential barriers that facilitate minority carrier collection.

[0050] Step 2: Prepare antimony-based infrared photovoltaic cell structure.

[0051] The fabrication process for antimony-based infrared photovoltaic cell structure 5 is similar to that for multi-junction gallium arsenide cell structure 3, with the main differences being the materials and parameters. The top subcell emitter (N region) material is GaInAsSb; the base (P region) material is GaInAsSb. The bottom subcell emitter (N region) material is InAsSb; the base (P region) material is InAsSb. The doping concentration in the top subcell emitter (N region) is (9-10)×10E+17cm 3 ; The doping concentration of the base region (P region) is (3.5-4)×10E+l7cm 3 The doping concentration of the bottom sub-cell emission region (N region) is 10×10E+l7cm 3 ; The doping concentration of the base region (P region) is 1×10E+l7cm 3 The thickness of the top sub-cell emitter region is 0.2μm, and the thickness of the base region is 7-8.5μm; the thickness of the bottom sub-cell emitter region is 0.1μm, and the thickness of the base region is 1.4-1.8μm.

[0052] Step three: the perovskite / organic tandem stacked cell structure.

[0053] This example integrates a wide-bandgap perovskite device with a narrow-bandgap organic bulk heterojunction cell to fabricate a high-efficiency tandem perovskite / organic tandem solar cell 1-5. The tandem device is fabricated using a CsPbI2Br perovskite material as the wide-bandgap front-stage cell layer, a ZnO / Ag(2nm) / MoO3 multilayer as the intermediate carrier recombination layer 1-7, and PM6:Y6 and PTB7-Th:O6T-4F as the narrow-bandgap rear-stage cell layers 1-9.

[0054] In the perovskite / organic tandem cell structure, the wide-bandgap front-stage cell is prepared using an ITO / ZnO / SnO2 / CsPbI2Br / HTL / Ag structure: First, the ITO glass is ultrasonically cleaned with deionized water and isopropyl alcohol for 8-12 minutes, then dried in an oven and further surface treated with oxygen plasma for 3-5 minutes. The first step is to spin-coat a layer of 38-42 nm thick zinc oxide nanoparticles on the ITO glass at a speed of 3000 rpm for 28-32 seconds, followed by drying on a hot plate at 58-62 degrees Celsius for 4-6 minutes. Then, a layer of 28-32 nm tin oxide nanoparticles in water is spin-coated at a speed of 2500 rpm for 28-32 seconds, and heated on a hot plate at 145-155 degrees Celsius in air for 8-12 minutes. The prepared ITO glass is then transferred to a nitrogen atmosphere glove box for spin coating of the perovskite solution. Lead iodide and cesium bromide were dissolved in a 1:1 molar ratio in a 9:1 volume ratio of DMSO (dimethyl sulfoxide) and DMF (N,N-dimethylformamide) solvent mixture to a concentration of 1.2 mol / L. The mixture was stirred overnight in a nitrogen glove box. The perovskite precursor solution was spin-coated onto the ZnO / SnO2 layer using a one-step spin coating method, spinning at 1500 rpm for 8-12 seconds followed by 28-32 seconds. The coated wafer was then heated on a hot plate at 42-48°C for 28-32 seconds. After color change, it was placed on a hot plate at 195-205°C for 0.8-1.2 minutes. A 5 mg / mL solution of PDCBT dissolved in o-dichlorobenzene was then spin-coated at 1500 rpm for 38-42 seconds.

[0055] The narrow-bandgap backstage cell utilizes an ITO / ZnO / BHJ / MoO3 / Ag structure. The zinc oxide layer is spin-coated using the same method described above. Bulk heterojunction solutions of PTB7-Th:O6T-4F and PM6:Y6 are dissolved in chlorobenzene at a mass ratio of 1:1 and 1:2, respectively. The solutions are prepared to a donor concentration of 10 mg / mL, with 0.5% DIO as an additive. The solutions are stirred overnight in a glove box. The bulk heterojunction solutions are spin-coated onto ITO / ZnO glass substrates at 2000 rpm for one minute, followed by annealing on a hot plate at 105-115°C for 8-12 minutes.

[0056] All devices use vacuum evaporation at 100-110 Mbar to deposit 8-12 nm thick MoO₃ and 95-105 nm thick Ag as electrodes. A ZnO nanoparticle solution is then spin-coated at 2000 rpm for 28-32 seconds to form the ZnO layer, which serves not only as part of the ICL (interconnect layer) but also as the electron transport layer (ETL) of the subsequent cell stage. Therefore, the ZnO layer is relatively thick, at 85-95 nm. This provides adequate protection for the perovskite layer during the subsequent spin-coating process, preventing damage. The BHJ film (bulk heterojunction) is then spin-coated.

[0057] The wide-bandgap front-stage cell and the narrow-bandgap back-stage cell are connected via a MoO3 / Ag / ZnO ICL (interlayer cladding) structure: ITO / ZnO (10nm) / SnO2 (30nm) / CsPbI2Br (240nm) / PDCBT (30nm) / MoO3 (10nm) / Ag (2nm) / ZnO (90nm) / BHJ / MoO3 (10nm) / Ag (100nm). An ultra-thin Ag layer ensures sufficient exciton recombination in the carrier recombination layer, improving the performance of the stacked device. A relatively thick ZnO layer is required on the narrow-bandgap back-stage cell to protect the underlying layer from damage during the deposition of the upper layers. The CsPbI2Br film thickness is the same as that used in optimized single-junction perovskite solar cells (500nm). The thicknesses of PM6:Y6 and PTB7-Th:O6T-4F films are 110 nm and 100 nm, respectively, which is roughly the same as the thickness of the optimized single-junction organic solar cells.

[0058] Step 4: Place the multi-junction gallium arsenide cell structure, antimony-based infrared photovoltaic cell structure, and perovskite / organic tandem stacked cell structure prepared in steps 1, 2, and 3 side by side in sequence, and use an insulating separator layer to separate adjacent cell structures to form a complete cell body.

[0059] In some embodiments, a transmissive three-channel micro-nano grating device with a connecting layer is fabricated: the grating body and the connecting layer are stacked and fixed together, and then the connecting layer is bonded to the cell body. Sunlight is split by the micro-nano grating device into three approximate wavelengths: infrared, visible, and ultraviolet. These wavelengths are then projected onto the three corresponding cells, improving photovoltaic conversion efficiency.

[0060] In some other embodiments, a light-guiding layer is also prepared. The light-guiding layer is disposed between the transmissive three-channel micro-nano grating device and the cell body. The light-guiding layer is used to guide infrared light to the antimony-based infrared photovoltaic cell structure, to guide visible light to the multi-junction gallium arsenide cell junction, and to guide ultraviolet light to the perovskite / organic tandem stack cell structure, further improving photovoltaic conversion efficiency.

Claims

1. A hybrid multi-band photovoltaic cell, comprising a cell body; characterized in that: The battery body includes a perovskite / organic tandem stacked cell structure, a multi-junction gallium arsenide cell structure, and an antimony-based infrared photovoltaic cell structure that are arranged side by side and separated by an insulating layer; The perovskite / organic tandem cell structure comprises a stacked wide bandgap front-stage cell and a narrow bandgap rear-stage cell; a carrier recombination layer is provided between the wide bandgap front-stage cell and the narrow bandgap rear-stage cell; the wide bandgap front-stage cell uses perovskite as a light absorption layer; and the narrow bandgap rear-stage cell uses an organic photovoltaic material as a light absorption layer; The multi-junction gallium arsenide battery structure includes a plurality of sub-battery units stacked in sequence and connected in series via tunnel junctions; each sub-battery unit uses gallium arsenide-based materials with different band gaps; The antimony-based infrared photovoltaic cell structure includes a top sub-cell and a bottom sub-cell stacked in sequence and connected in series via a tunnel junction. The top sub-cell is constructed based on GaInAsSb; the bottom sub-cell is constructed based on InAsSb material.

2. The hybrid multi-band photovoltaic cell according to claim 1, characterized in that: The wide bandgap front-stage cell and the narrow bandgap rear-stage cell both include an electron transport layer, a perovskite layer and a hole transport layer.

3. The hybrid multi-band photovoltaic cell according to claim 2, characterized in that: The material of the perovskite in the wide bandgap front-stage cell is CsPbI2Br; the organic photovoltaic material perovskite layer in the narrow bandgap rear-stage cell is a bulk heterojunction of a mixed material of PTB7-Th and PM6.

4. The hybrid multi-band photovoltaic cell according to claim 3, characterized in that: The multi-junction gallium arsenide cell structure further includes an anti-reflection layer and an electrode layer.

5. The hybrid multi-band photovoltaic cell according to claim 1, characterized in that: The number of sub-battery units in the multi-junction gallium arsenide battery structure is three; the three sub-battery units are a top sub-battery, a middle sub-battery and a bottom sub-battery, each including a window layer, an emitter region, a base region and a back electric field layer; the materials of the window layer, emitter region, base region and back electric field layer in the top sub-battery are n-AlInP, n-GaInP, p-GaInP and p-AlGaInP respectively; the materials of the window layer, emitter region, base region and back electric field layer in the middle sub-battery are n-GaInP, n-InGaAs, p-InGaAs and p-AlGaAs respectively; the materials of the window layer, emitter region, base region and back electric field layer in the bottom sub-battery are n-GaAs, n-Ge, p-Ge and p-Ge respectively.

6. The hybrid multi-band photovoltaic cell according to claim 1, characterized in that: The top subcell and bottom subcell in the antimony-based infrared photovoltaic cell structure both include an emission region and a base region; the materials of the emission region and the base region in the top subcell are N-GaInAsSb and P-GaInAsSb, respectively; the materials of the emission region and the base region in the bottom subcell are N-InAsSb and P-InAsSb, respectively.

7. The hybrid multi-band photovoltaic cell according to claim 1, characterized in that: It also includes a transmissive three-channel micro-nano grating device covering the light-incoming side of the battery body; the transmissive three-channel micro-nano grating device includes a grating body and a connecting layer covering the side of the grating body close to the battery body; the material of the grating body is silicon dioxide; the medium in the grating groove of the grating body is air; the material of the connecting layer is tantalum pentoxide; the grating period in the grating body is 1000nm to 1100nm.

8. A preparation method for preparing a hybrid multi-band photovoltaic cell according to claim 1, characterized in that: The preparation method comprises: Fabrication of a multi-junction GaAs cell structure: First, n-type doping is performed on a p-doped Ge substrate to form the emitter region of the bottom sub-cell; then two-dimensional nucleation is performed at the step, followed by growth of a buffer layer; and continued epitaxial growth is performed to form the middle sub-cell, the top sub-cell, and the tunnel junction used to separate the sub-cells; Preparation of antimony-based infrared photovoltaic cell structure: epitaxial growth on the substrate to form bottom sub-cell and top sub-cell; Preparation of perovskite / organic tandem stacked cell structure: forming a wide bandgap front-stage cell, a carrier recombination layer, and a narrow bandgap back-stage cell in sequence by layer-by-layer spin coating; The multi-junction gallium arsenide cell structure, the antimony-based infrared photovoltaic cell structure, and the perovskite / organic series stacked cell structure are arranged side by side in sequence, and adjacent cell structures are separated by an insulating separation layer.

9. A preparation method according to claim 8, characterized in that: The MO source for the epitaxial growth of the multi-junction gallium arsenide cell structure is one or more of trimethyl gallium, trimethyl aluminum, and trimethyl indium; the doping source is one or more of disilane, diethyl antimony, dimethyl zinc, and carbon tetrabromide; the special gas is one or more of arsine and phosphine; and hydrogen is used as the carrier gas.

10. A preparation method according to claim 8, characterized in that: In the process of preparing the perovskite / organic tandem stacked cell structure, an 85-95 nm ZnO layer is spin-coated, which serves as the interconnection layer between the carrier recombination layer and the narrow-bandgap subsequent cell, as well as the electron transport layer of the narrow-bandgap subsequent cell.

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