Full-perovskite laminated solar cell based on narrow-band gap buried interface modification and preparation method and application of full-perovskite laminated solar cell

Abstract

The invention discloses a full-perovskite laminated solar cell based on narrow-band-gap buried interface modification and a preparation method and application of the full-perovskite laminated solar cell. According to the preparation method of the full-perovskite laminated solar cell based on narrow-band-gap buried interface modification, hydrazine sulfate and lead iodide are introduced to serve as an interface modification layer between a narrow-band-gap perovskite layer and a hole transport layer, and through the synergistic effect of the hydrazine sulfate and the lead iodide, surface defects of the hole transport layer can be effectively passivated; moreover, the hole mobility can be improved remarkably, and the photoelectric conversion efficiency of the cell is improved based on the preparation method of the full-perovskite laminated solar cell. The full-perovskite laminated solar cell has high photovoltaic performance and can be widely applied to the photoelectric field.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of optoelectronic materials and devices, and particularly relates to a full-perovskite tandem solar cell based on a narrow-bandgap buried bottom interface modification and a preparation method and application thereof. BACKGROUND

[0002] The overexploitation and consumption of fossil energy continue to exacerbate the global climate crisis, and accelerating the transformation of energy structure to clean energy has become the widespread consensus of the international community. In recent years, major economies around the world have successively introduced renewable energy development strategies, promoting the large-scale popularization of clean energy technologies such as solar, wind, water and tidal energy, and continuously increasing the proportion of clean energy in the global energy consumption structure. As the most abundant renewable energy, the development potential of solar energy is significant. If the effective conversion rate is 0.013%, it can meet the current global energy demand. As the core technology of solar energy utilization, although the traditional photovoltaic technology based on silicon materials has been mature, its large-scale commercial application is still subject to high cost, process complexity and environmental pollution. Under this background, perovskite photovoltaic technology has rapidly risen and become the research frontier in this field due to its significant advantages such as simple preparation process, low cost, flexible preparation capability and excellent photoelectric conversion performance.

[0003] Currently, the photoelectric conversion efficiency of lead-based perovskite solar cells has been significantly broken through, and the progress of large-area thin film preparation technology has promoted the process of its large-scale application. However, based on the Shockley-Queisser limit theory, the theoretical efficiency upper limit of single-junction devices with a bandgap of 1.55 eV has encountered a bottleneck. In order to break through this limit, building a full-perovskite tandem solar cell has become an effective way, and the theoretical efficiency of double-junction tandem cells is significantly improved compared to that of single-junction devices. The full-perovskite tandem cell is composed of a wide-bandgap and a narrow-bandgap perovskite subcell and an interconnection layer in series, and the performance of the tin-lead narrow-bandgap perovskite subcell is the key factor restricting the realization of high-efficiency tandem devices.

[0004] However, the introduction of tin element inevitably leads to problems such as easy oxidation of divalent tin, too fast crystallization kinetics, uneven component distribution, resulting in high-density defect states of perovskite films, low charge transport efficiency and poor interface contact. And although there have been many studies on the optimization of the photoelectric performance and environmental stability of tin-lead perovskite through additive engineering and interface modification strategies, the poor buried bottom interface contact and poor effect are still the core bottleneck restricting the improvement of device performance.

[0005] Therefore, it is urgent to develop a preparation method that can simultaneously solve the oxidation problem of divalent tin and ensure that the modified layer has excellent effect, so that the full-perovskite tandem solar cell prepared has excellent cell performance. SUMMARY

[0006] In view of the defects in the prior art, the present application provides a full perovskite stacked solar cell based on narrow-band-gap buried bottom interface modification and a preparation method and application thereof.

[0007] The present application provides a preparation method of a full perovskite stacked solar cell based on narrow-band-gap buried bottom interface modification, comprising the following steps: S1: cleaning and drying a conductive glass substrate; S2: coating a hole transport material above the conductive glass substrate, and obtaining a hole transport layer after annealing; S3: coating a wide-band-gap FA 0.8 MA 0.1 Cs 0.1 Pb(I 0.6 Br 0.4 )3 perovskite precursor material above the hole transport layer, and obtaining a smooth and dense wide-band-gap perovskite layer after annealing; S4: coating an electron transport material above the wide-band-gap perovskite layer, and then vacuum evaporating a C 60 thin film to form an electron transport layer; S5: depositing tin oxide on the electron transport layer by using atomic layer deposition technology to obtain an interconnection layer; S6: vacuum evaporating a metal material on the interconnection layer as a composite layer; S7: coating a hole transport material above the composite layer, and obtaining a hole transport layer after annealing; S8: depositing a mixed solution of lead iodide and hydrazine sulfate on the hole transport layer, and obtaining a buried bottom interface modification layer after annealing; S9: coating a narrow-band-gap Cs 0.1 FA 0.9 Pb 0.5 Sn 0.5 I3 perovskite precursor material above the buried bottom interface modification layer, and obtaining a smooth and dense narrow-band-gap perovskite layer after annealing; S10: coating an electron transport material above the narrow-band-gap perovskite layer, and then vacuum evaporating a C 60 thin film to form an electron transport layer; S11: evaporating an interface modification layer on the electron transport layer, and then evaporating a metal electrode, to obtain the full perovskite stacked solar cell based on narrow-band-gap buried bottom interface modification.

[0008] The present application uses hydrazine sulfate and lead iodide as the buried bottom interface modification layer of tin-lead perovskite and full perovskite stacked solar cell, effectively passivates defects at the buried bottom interface, relieves residual strain of the perovskite film, and synchronously improves the performance of the full perovskite photovoltaic device. The hydrazine sulfate passivates defects at the buried bottom interface of the perovskite film by reacting with the hole transport layer NiO XForming a coordination bond, effectively passivating its surface defects, doping lead iodide can increase the work function of the hole transport layer and reduce the interface energy loss, directly promoting the significant improvement of the hole mobility, optimizing the electrical transport characteristics, greatly improving the conductivity, which is conducive to improving the photoelectric conversion efficiency of the device. The present application also finds that the synergistic effect of hydrogen bond interaction and coordination between hydrazine sulfate and lead iodide can induce the directional growth of perovskite crystals along the vertical direction. This process not only can greatly reduce the tin vacancy defect density of the buried interface, but also can effectively relieve the residual strain in the crystal, thereby significantly improving the quality of the narrow-bandgap perovskite film and significantly inhibiting the non-radiative recombination process.

[0009] Furthermore, the present application also prepares a dense tin oxide interconnection layer by atomic layer deposition, which well blocks the damage of the solvent to the wide-bandgap sub-cell during the preparation of the narrow-bandgap sub-cell; and the construction of the high-efficiency recombination layer is realized by introducing gold nanoclusters.

[0010] Further, the wide-bandgap FA 0.8 MA 0.1 Cs 0.1 Pb(I 0.6 Br 0.4 )3 perovskite precursor material preparation method comprises the following steps: The formamidinium iodide, methylamine iodide, cesium iodide, lead iodide and lead bromide are dissolved in a solvent to form a perovskite precursor solution, the concentration is 0.8-1.4 mmol / mL, and the solution is stirred at 30-80℃ for 1-5 hours until completely dissolved, thereby obtaining the wide-bandgap perovskite precursor material, wherein the molar ratio of the formamidinium iodide, methylamine iodide, cesium iodide, lead iodide and lead bromide is (0.78-0.81):0.1:0.1:(0.37-0.42):(0.59-0.61), and the solvent is a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide; The preparation method of the narrow-bandgap perovskite precursor material in the step S9 comprises the following steps: The formamidinium iodide, cesium iodide, lead iodide, stannous iodide, stannous fluoride and formamidinium acetate are dissolved in a solvent to form a perovskite precursor solution, the concentration is 1.5-2.0 mmol / mL, and the solution is stirred at 30-80℃ for 1-5 hours until completely dissolved, thereby obtaining the narrow-bandgap perovskite precursor material, wherein the molar ratio of the formamidinium iodide, cesium iodide, lead iodide, stannous iodide, stannous fluoride and formamidinium acetate is (0.88-0.91):0.1:(0.49-0.52):(0.49-0.52):0.05:(0.78-0.81), and the solvent is N,N-dimethylformamide.

[0011] Further, the preparation method of the mixed solution of lead iodide and hydrazine sulfate in the step S8 comprises the following steps: 2-10 parts by weight of lead iodide and 0.5-2 parts by weight of hydrazinium sulfate are dissolved in N,N-dimethylformamide solvent, and stirred at 30-80°C for 1-5 hours until completely dissolved, to obtain a mixed solution of lead iodide and hydrazinium sulfate.

[0012] Further, the mass ratio of lead iodide to hydrazinium sulfate in step S8 is (1-16):1, preferably (2-10):1, and the spin coating speed is 4000-6000 r / min, and the time is 20-30 s.

[0013] Further, the spin coating method is used to coat the perovskite precursor material in two steps in step S3: first, spin coating at a first speed for a first time period, and then spin coating at a second speed for a second time period, the first speed is 900-1200 rpm, and the first time period is 8-13 seconds; the second speed is 3000-6000 rpm, and the second time period is 30-50 seconds; wherein, in the last 30 seconds of spin coating the broadband gap FA 0.8 MA 0.1 Cs 0.1 Pb(I 0.6 Br 0.4 )3 perovskite precursor material, 400-600 μL of anti-solvent is added dropwise; the anti-solvent can be ethyl ether; In step S9, the perovskite precursor material is deposited by one-step anti-solvent-free spin coating, the spin coating speed is 4000-5000 r / min, the time is 30-40 s, the annealing temperature is 100-120°C, and the processing time is 10-20 minutes.

[0014] Further, the hole transport material in step S2 is MeO-4PACz solution, and the preparation method is to dissolve MeO-4PACz in isopropanol solution at a concentration of 1-5 mg / mL, the spin coating speed is 4000-6000 r / min, the time is 20-30 s, and the annealing includes annealing at 90-120°C for 10-15 min; The hole transport material in step S7 is PEDOT:PSS / NiO X , wherein NiO X is dispersed in ultrapure water at a concentration of 10-20 mg / mL, the spin coating speed is 4000-6000 r / min, and the time is 20-30 s.

[0015] Further, the electron transport material in steps S4 and S10 is PCBM, and the preparation method is to dissolve PCBM in chlorobenzene solution at a concentration of 5-15 mg / mL, the spin coating speed is 2000-3000 r / min, and the time is 30-40 s.

[0016] Further, the conductive glass substrate is FTO transparent conductive glass.

[0017] Further, the thickness of the interconnection layer in step S5 is 43-46 nm.

[0018] Further, the metal material in step S6 is gold, and the thickness is 0.9-1.2 nm. By introducing gold nanoclusters, a high-efficiency composite layer is constructed.

[0019] Further, the C 60 The film thickness is 15-20 nm, and the vacuum evaporation rate is 0.5-1 angstrom / second.

[0020] Further, step S7 comprises the following steps: after spin coating PEDOT:PSS on the composite layer, annealing at 115-122℃ for 14-15 minutes, and then spin coating NiO X , and then annealing at 115-122℃ for 14-15 minutes.

[0021] Further, the annealing temperature in step S8 is 100-120℃, and the processing time is 5-10 minutes.

[0022] Further, the interface modification layer in step S11 is BCP, and the thickness is 1-5 nm. The metal electrode is Ag, and the thickness is 100-120 nm.

[0023] The application also provides a perovskite solar cell stack prepared by the preparation method.

[0024] The application also provides application of the perovskite solar cell stack in the field of optoelectronics.

[0025] The application also provides an optoelectronic device comprising the buried bottom interface modification layer.

[0026] Compared with the prior art, the application has the following technical effects: (1) The application provides that the mixed solution of hydrazine sulfate and lead iodide is deposited on the hole transport layer as a buried bottom interface modification layer, which can form a coordination bond with NiO X , effectively passivates the surface defects, increases the work function of the hole transport layer, reduces the interface energy loss, and significantly improves the photoelectric conversion efficiency of the device; (2) The specific buried bottom interface modification layer provided by the application can also induce perovskite crystals to grow in the vertical direction, significantly improve the quality of the narrow-bandgap perovskite film, and further improve the electrical performance of the device. (3) The preparation method of the full perovskite stacked solar cell based on the narrow-band buried bottom interface modification provided by the application realizes the construction of a high-efficiency photoelectric device through the cooperation between the interface layers. (4) The full perovskite stacked solar cell provided by the application has excellent cell performance, especially high photoelectric conversion efficiency, and can be widely applied in the photoelectric field. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the application, the drawings needed to be used in the embodiments will be briefly introduced as follows. It should be understood that the following drawings only show some of the embodiments of the application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0028] Figure 1 The full perovskite stacked solar cell device structure prepared for the embodiment 1 of the application is shown in the figure. Figure 2 The SEM images of the narrow-band perovskite thin film prepared in a nitrogen atmosphere for the control example 3 (Control) and the embodiment 1 of the application are shown in the figure. Figure 3 The grazing incidence wide-angle X-ray scattering images of the narrow-band perovskite thin film prepared in a nitrogen atmosphere for the control example 3 (Control) and the embodiment 1 of the application without using buried bottom interface modification and using buried bottom interface modification are shown in the figure. Figure 4 The J-V curve images of the full perovskite stacked solar cell prepared in a nitrogen atmosphere for the control example 3 (Control) and the embodiment 1 of the application without using buried bottom interface modification and using buried bottom interface modification are shown in the figure. DETAILED DESCRIPTION

[0029] In order to enable those skilled in the art to better understand the application scheme, the technical solutions in the embodiments of the application will be clearly and completely described as follows. Obviously, the described embodiments are only some of the embodiments of the application, but not all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor should be within the scope of the application.

[0030] EMBODIMENT The application will be further described below in combination with specific embodiments and comparative examples. The following specific embodiments are preferred embodiments of the application, but the embodiments of the application are not limited by the following examples, especially not limited to the types of raw materials used in the following specific examples.

[0031] I. The sources of raw materials for the examples and comparative examples are as follows: The experimental methods used in the examples and comparative examples are conventional methods unless otherwise specified; the raw materials (materials, reagents, etc.) used are commercially available unless otherwise specified.

[0032] II. Test methods for various properties Photovoltaic performance parameter test: using a solar simulator, the open-circuit voltage (V OC ), short-circuit current density (J SC ), fill factor (FF) and photoelectric conversion efficiency (Efficiency) of the cell were tested under standard test conditions (AM1.5G light).

[0033] Example 1 Example 1: A narrow-bandgap perovskite thin film and a full-perovskite tandem solar cell with a buried interface passivated by hydrazinium sulfate and lead iodide were prepared, including the following steps: S1: The etched FTO transparent conductive glass was sequentially ultrasonically cleaned in ethanol, ultrapure water with cleaning agent, ultrapure water, and ethanol for 30 min each, and then dried with nitrogen and placed in an oven for baking to obtain a clean FTO substrate, which was then treated with ultraviolet ozone for 15 minutes; S2: 1 mg of MeO-4PACz was completely dissolved in 1 mL of isopropanol solvent to prepare a 1 mg / mL MeO-4PACz spin coating solution. 45 μL of the spin coating solution was dropped onto the conductive glass using a pipette gun, and then spun at a speed of 4000 r / min for 30 s, followed by annealing at 100°C for 10 min to obtain a hole transport layer; S3: 172.0 mg of formamidinium iodide, 19.9 mg of methylamine iodide, 32.5 mg of cesium iodide, 275.3 mg of lead bromide, and 253.6 mg of lead iodide were dissolved in 1 mL of a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide in a volume ratio of 3:1, and stirred at 60°C for 2 hours until completely dissolved to prepare a wide-bandgap perovskite precursor material. The FTO substrate coated with the hole transport layer was transferred into a nitrogen environment glove box, and 60 μL of the wide-bandgap perovskite precursor material was uniformly spin-coated on the hole transport layer using a spin coater. The specific spin coating process was a two-step spin coating method: the first step was to spin at 1000 rpm for 10 s to evenly spread the perovskite solution, and the second step was to spin at 4000 rpm for 45 s. At 30 s before the end of the second step, 500 μL of diethyl ether was quickly dropped onto the rotating substrate as an anti-solvent to immediately change the perovskite into an intermediate phase. The deposited thin film was then annealed at 100°C for 10 minutes in a nitrogen atmosphere to obtain a wide-bandgap perovskite layer; S4: 10 mg of PCBM was weighed and completely dissolved in 1 mL of chlorobenzene solvent to prepare a 10 mg / mL PCBM spin coating solution. The PCBM spin coating solution was spin-coated onto the wide-bandgap perovskite film at a spin speed of 2000 r / min for 30 s, and then a 20 nm C 60 layer was vacuum evaporated at a rate of 0.5 angstrom / s to obtain an electron transport layer; S5: A tin oxide interconnection layer was deposited on the electron transport layer by atomic layer deposition technology. The tin source was set to 55°C, and after the pressure stabilized, the deposition cycle number was set to 450. After deposition, the tin source was turned off. When the pressure was atmospheric pressure, the FTO substrate was removed to obtain an interconnection layer with a thickness of 45 nm; S6: A 1 nm thick gold metal layer was evaporated and deposited on the interconnection layer as a composite layer for standby; S7: 10 mg of NiO X was weighed and completely dispersed in 1 mL of ultrapure water to prepare a 10 mg / mL NiO X spin coating solution. 45 μL of hole transport material PEDOT:PSS was dropped onto the FTO substrate using a pipette gun. After spinning at a speed of 4000 r / min for 30 s, annealing was performed at 120°C for 15 min. After cooling, 45 μL of NiO X spin coating solution was dropped onto the FTO substrate. After spinning at a speed of 4000 r / min for 30 s, annealing was performed at 120°C for 15 min to obtain a hole transport layer; S8: 2 mg of lead iodide and 1 mg of hydrazine sulfate were dissolved in 1 mL of N,N-dimethylformamide solvent and stirred at 60°C for 3 hours until completely dissolved to obtain a mixed solution of lead iodide and hydrazine sulfate. The FTO substrate was transferred into a nitrogen environment glove box, 60 μL of the mixed solution was spin-coated at a speed of 4000 r / min for 30 s, and then annealed at 100°C for 10 min to obtain a buried interface modification layer; S9: 278.6 mg of formamidinium iodide, 46.8 mg of cesium iodide, 435.7 mg of lead iodide, 352.0 mg of stannous iodide, 14.8 mg of stannous fluoride, and 149.9 mg of formamidinium acetate were dissolved in 1 mL of N,N-dimethylformamide solvent and stirred at 60°C for 5 hours until completely dissolved to prepare a narrow-bandgap perovskite precursor material. 60 μL of the narrow-bandgap perovskite precursor material was uniformly spin-coated on the FTO substrate using a spin coater. The specific spin coating process was as follows: spin-coating at a speed of 4000 r / min for 30 s, and then annealing the deposited film in a nitrogen atmosphere at 120°C for 15 min to obtain a narrow-bandgap perovskite layer; S10: Spin-coating PCBM solution onto a narrow bandgap perovskite film at a spin speed of 2000 r / min for 30 s. Then, vacuum evaporation is used to deposit 20 nm of C at a rate of 0.5 Å / s. 60 This forms an electron transport layer; S11: A 5 nm interface modification layer BCP is deposited above the electron transport layer, and then a 100 nm metal electrode Ag is deposited to obtain the full perovskite tandem solar cell based on narrow bandgap buried interface modification. The photoelectric performance of the above-mentioned all-perovskite tandem solar cells based on narrow bandgap buried interface modification was tested under standard test conditions (AM1.5G illumination). The photoelectric conversion efficiency was 27.20%, the open-circuit voltage was 2.12V, and the short-circuit current was 15.95 mA / cm². 2 The fill factor is 80.43%. Figure 1 This is a schematic diagram of the structure of the all-perovskite tandem solar cell device prepared in Example 1; Figure 2 SEM images of narrow bandgap perovskite films prepared in nitrogen atmosphere for Comparative Example 3 (Control) and Example 1, where a is the film prepared without buried interface modification and b is the film prepared with buried interface modification. Figure 3 Grazing incidence wide-angle X-ray scattering (GRS) images of narrow bandgap perovskite films prepared in a nitrogen atmosphere for Comparative Example 3 (Control) and Example 1, with and without buried interface modification. Figure 4 The JV curves are for the all-perovskite tandem solar cells prepared in a nitrogen atmosphere for Comparative Example 3 (Control) and Example 1, with and without buried interface modification.

[0034] Example 2 Example 2 describes the preparation of a narrow bandgap perovskite thin film and an all-perovskite tandem solar cell with hydrazine sulfate and lead iodide passivating the buried interface, comprising the following steps: S1: The etched FTO transparent conductive glass was ultrasonically treated for 30 minutes each in ethanol, ultrapure water with cleaning agent, ultrapure water and ethanol, dried with nitrogen and baked in an oven to obtain a clean FTO substrate, and then treated with ultraviolet ozone for 15 minutes. S2: Weigh 3 mg of MeO-4PACz and completely dissolve it in 1 mL of isopropanol solvent to prepare a 3 mg / mL MeO-4PACz spin-coating solution. Take 45 μL of the spin-coating solution and drop it onto a conductive glass using a pipette. After rotating at 5000 r / min for 20 s, anneal at 90℃ for 14 min to obtain the hole transport layer. S3: Weigh 172.0 mg of formamidinium iodide, 19.9 mg of methylamine iodide, 32.5 mg of cesium iodide, 275.3 mg of lead bromide, and 253.6 mg of lead iodide, dissolve them in 1 mL of a 3:1 mixture of N,N-dimethylformamide and dimethyl sulfoxide, and stir at 40°C for 5 hours until completely dissolved to prepare a wide-bandgap perovskite precursor material. Transfer the FTO substrate coated with the hole transport layer into a glove box under nitrogen atmosphere. Take 60 μL of the wide-bandgap perovskite precursor material and spin-coat it evenly onto the hole transport layer. The specific spin-coating process is a two-step spin-coating method: the first step is to maintain a rotation speed of 1200 rpm for 8 s to evenly spread the perovskite solution; the second step is to maintain a rotation speed of 6000 rpm for 35 s. 30 seconds before the end of the second step... At s, 600 μL of diethyl ether was rapidly dropped onto the rotating substrate as an antisolvent, causing the perovskite to immediately become the meso phase. The deposited film was then annealed at 120 °C for 15 minutes in a nitrogen atmosphere to obtain a wide-bandgap perovskite layer. S4: Weigh 6 mg of PCBM and completely dissolve it in 1 mL of chlorobenzene solvent to prepare a 6 mg / mL PCBM spin-coating solution. Spin-coat the PCBM solution onto a wide-bandgap perovskite film at a spin speed of 3000 r / min for 20 s. Then, use vacuum evaporation to deposit 15 nm of C at a rate of 1 Å / s. 60 Thus, an electron transport layer is obtained; S5: Atomic layer deposition technology was used to deposit tin oxide as an interconnect layer on the electron transport layer. The tin source was set to 55°C. After the pressure stabilized, the number of deposition cycles was set to 450. After the deposition was completed, the tin source was turned off. When the pressure was atmospheric pressure, the FTO substrate was removed to obtain an interconnect layer with a thickness of 45 nm. S6: A 1.2 nm thick layer of metallic gold is deposited on the interconnect layer by method evaporation as a composite layer for later use; S7: Weigh out 15 mg of NiO X It was completely dispersed in 1 mL of ultrapure water to prepare a NiO concentration of 15 mg / mL. X For spin coating, take 45 μL of hole transport material PEDOT:PSS and drop it onto an FTO substrate using a pipette. Spin-coate at 6000 r / min for 25 s, then anneal at 120℃ for 15 min. After cooling, take 45 μL of NiO... X Spin-coating solution was dropped onto an FTO substrate, and after being rotated at 6000 r / min for 25 s, it was annealed at 120℃ for 15 min to obtain a hole transport layer. S8: Weigh 2 mg of lead iodide and 1 mg of hydrazine sulfate and dissolve them in 1 mL of N,N-dimethylformamide solvent. Stir at 80 °C for 2 hours until completely dissolved to obtain a mixed solution of lead iodide and hydrazine sulfate. Transfer the FTO substrate into a glove box under nitrogen atmosphere. Take 60 μL of the mixed solution, rotate it at 5000 r / min for 20 s, and then anneal it at 120 °C for 5 min to obtain the buried interface modification layer. S9: Weigh 278.6 mg of formamidinium iodide, 46.8 mg of cesium iodide, 435.7 mg of lead iodide, 352.0 mg of stannous iodide, 14.8 mg of stannous fluoride, and 149.9 mg of formamidinium acetate, dissolve them in 1 mL of N,N-dimethylformamide solvent, and stir at 60°C for 5 hours until completely dissolved to prepare a narrow bandgap perovskite precursor material. Take 60 μL of the narrow bandgap perovskite precursor material and spin coat it evenly onto an FTO substrate using a spin coater. The specific spin coating process is as follows: spin coat at 6000 r / min for 20 s. After spin coating, anneal the deposited film at 100°C in a nitrogen atmosphere for 20 minutes to obtain a narrow bandgap perovskite layer. S10: Spin-coating PCBM solution onto a narrow bandgap perovskite film at a spin speed of 3000 r / min for 20 s. Then, vacuum evaporation is used to deposit 20 nm of C at a rate of 0.5 Å / s. 60 This forms an electron transport layer; S11: A 2 nm interface modification layer BCP is deposited above the electron transport layer, followed by a 120 nm metal electrode Ag, to obtain the full perovskite tandem solar cell based on narrow bandgap buried interface modification. The photoelectric performance of the above-mentioned all-perovskite tandem solar cells based on narrow bandgap buried interface modification was tested under standard test conditions (AM1.5G illumination). The photoelectric conversion efficiency was 27.05%, the open-circuit voltage was 2.12V, and the short-circuit current was 15.92 mA / cm². 2 The fill factor is 80.28%.

[0035] Example 3 The difference between Example 3 and Example 1 is that in step S8, 4 mg of lead iodide and 1 mg of hydrazine sulfate are weighed and dissolved in 1 mL of N,N-dimethylformamide solvent. The solution is stirred at 60°C for 3 hours until completely dissolved to obtain a mixed solution of lead iodide and hydrazine sulfate. The FTO substrate is transferred into a glove box under nitrogen atmosphere. 60 μL of the mixed solution is taken, rotated at 4000 r / min for 30 s, and then annealed at 100°C for 10 min to obtain the buried interface modification layer. The photoelectric performance of the above-mentioned all-perovskite tandem solar cells based on narrow bandgap buried interface modification was tested under standard test conditions (AM1.5G illumination). The photoelectric conversion efficiency was 27.08%, the open-circuit voltage was 2.12V, and the short-circuit current was 15.96 mA / cm². 2 The fill factor is 80.03%.

[0036] Example 4 The difference between Example 4 and Example 1 is that in step S8, 10 mg of lead iodide and 1 mg of hydrazine sulfate are weighed and dissolved in 1 mL of N,N-dimethylformamide solvent. The solution is stirred at 60°C for 3 hours until completely dissolved to obtain a mixed solution of lead iodide and hydrazine sulfate. The FTO substrate is transferred into a glove box under nitrogen atmosphere. 60 μL of the mixed solution is taken, rotated at 4000 r / min for 30 s, and then annealed at 100°C for 10 min to obtain the buried interface modification layer. The photoelectric performance of the above-mentioned all-perovskite tandem solar cells based on narrow bandgap buried interface modification was tested under standard test conditions (AM1.5G illumination). The photoelectric conversion efficiency was 26.89%, the open-circuit voltage was 2.11V, and the short-circuit current was 15.97 mA / cm². 2 The fill factor is 79.79%.

[0037] Example 5 The difference between Example 5 and Example 1 is that in step S8, 8 mg of lead iodide and 0.5 mg of hydrazine sulfate are weighed and dissolved in 1 mL of N,N-dimethylformamide solvent. The solution is stirred at 60°C for 3 hours until completely dissolved to obtain a mixed solution of lead iodide and hydrazine sulfate. The FTO substrate is transferred into a glove box under nitrogen atmosphere. 60 μL of the mixed solution is taken, rotated at 4000 r / min for 30 s, and then annealed at 100°C for 10 min to obtain the buried interface modification layer. The photoelectric performance of the above-mentioned all-perovskite tandem solar cells based on narrow bandgap buried interface modification was tested under standard test conditions (AM1.5G illumination). The photoelectric conversion efficiency was 26.77%, the open-circuit voltage was 2.11V, and the short-circuit current was 15.98 mA / cm². 2 The fill factor is 79.43%.

[0038] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that in step S8, 1 mg of hydrazine sulfate is weighed and dissolved in 1 mL of N,N-dimethylformamide solvent, and stirred at 60°C for 3 hours until completely dissolved to obtain a mixed solution of lead iodide and hydrazine sulfate. The FTO substrate is then transferred into a glove box under nitrogen atmosphere, and 60 μL of the mixed solution is taken and rotated at 4000 r / min for 30 s, followed by annealing at 100°C for 10 min to obtain the buried interface modification layer. The photoelectric performance of the above-mentioned all-perovskite tandem solar cells based on narrow bandgap buried interface modification was tested under standard test conditions (AM1.5G illumination). The photoelectric conversion efficiency was 26.47%, the open-circuit voltage was 2.12V, and the short-circuit current was 15.84 mA / cm². 2 The fill factor is 78.82%.

[0039] Comparative Example 2 The difference between Comparative Example 1 and Example 1 is that in step S8, 2 mg of hydrazine sulfate is weighed and dissolved in 1 mL of N,N-dimethylformamide solvent, and stirred at 60°C for 3 hours until completely dissolved to obtain a mixed solution of lead iodide and hydrazine sulfate. The FTO substrate is then transferred into a glove box under nitrogen atmosphere, and 60 μL of the mixed solution is taken and rotated at 4000 r / min for 30 s, followed by annealing at 100°C for 10 min to obtain the buried interface modification layer. The photoelectric performance of the above-mentioned all-perovskite tandem solar cells based on narrow bandgap buried interface modification was tested under standard test conditions (AM1.5G illumination). The photoelectric conversion efficiency was 26.39%, the open-circuit voltage was 2.13V, and the short-circuit current was 15.75 mA / cm². 2 The fill factor is 78.53%.

[0040] Comparative Example 3 The difference between Comparative Example 1 and Example 1 is that step S8 is not included; The photoelectric performance of the above-mentioned all-perovskite tandem solar cells based on narrow bandgap buried interface modification was tested under standard test conditions (AM1.5G illumination). The photoelectric conversion efficiency was 24.92%, the open-circuit voltage was 2.06V, and the short-circuit current was 15.88 mA / cm². 2 The fill factor is 76.18%.

[0041] Examples 1-5 employ the specific preparation method of this invention, introducing hydrazine sulfate and lead iodide as interface modification layers between the narrow bandgap perovskite layer and the hole transport layer. Hydrazine sulfate, through hydrogen bonding and synergistic coordination, induces perovskite growth perpendicular to the substrate, improving film quality, alleviating residual strain, and suppressing non-radiative recombination. Hydrazine sulfate also interacts with the NiO hole transport layer... XBy forming coordination bonds, surface defects are effectively passivated. Lead iodide doping can increase the work function of the hole transport layer and reduce interfacial energy loss, directly promoting a significant increase in hole mobility, optimizing electrical transport characteristics, and greatly improving electrical conductivity. This significantly enhances the photovoltaic performance of perovskite solar cells, and the photoelectric conversion efficiency of the fabricated all-perovskite tandem solar cells is above 26.5%.

[0042] Compared with Example 1, Comparative Example 1 only added hydrazine sulfate to the buried interface modification layer; Comparative Example 2 only added lead iodide to the buried interface modification layer compared with Example 1; and Comparative Example 3 did not prepare a buried interface modification layer compared with Example 1. All of these resulted in a deterioration in the morphology of the narrow bandgap perovskite film and affected the performance of the all-perovskite tandem solar cell.

[0043] Based on the above test data on the photovoltaic performance parameters of the all-perovskite tandem solar cells based on narrow bandgap buried interface modification, including open-circuit voltage, short-circuit current density, fill factor, and photoelectric conversion efficiency, the all-perovskite tandem solar cells prepared through Examples 1-5 have significant advantages over the comparative examples and can effectively meet the high standards of customers and the market.

[0044] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for fabricating an all-perovskite tandem solar cell based on narrow bandgap buried interface modification, characterized in that, Includes the following steps: S1: Clean and dry the conductive glass substrate; S2: A hole transport material is coated on a conductive glass substrate and annealed to obtain a hole transport layer. S3: Apply a wide-bandgap FA above the hole transport layer 0.8 MA 0.1 Cs 0.1 Pb(I 0.6 Br 0.4 )3 Perovskite precursor material, annealed to obtain wide-bandgap perovskite layer; S4: Apply an electron transport material over the wide-bandgap perovskite layer, followed by vacuum evaporation of C. 60 Thin film, forming an electron transport layer; S5: Tin oxide is deposited above the electron transport layer using atomic layer deposition technology to obtain the interconnect layer; S6: Vacuum evaporation of metallic material is used as a composite layer on the interconnect layer; S7: A hole transport material is coated on the composite layer and annealed to obtain a hole transport layer. S8: A mixed solution of lead iodide and hydrazine sulfate is deposited on the hole transport layer, and after annealing, a buried interface modification layer is obtained; S9: Apply a narrow-bandgap Cs coating above the substrate interface modification layer. 0.1 FA 0.9 Pb 0.5 Sn 0.5 I3 perovskite precursor material, after annealing, yields a narrow bandgap perovskite layer; S10: Electron transport material is coated on top of the narrow bandgap perovskite layer, followed by vacuum evaporation of C. 60 Thin film, forming an electron transport layer; S11: An interface modification layer is deposited above the electron transport layer, and then a metal electrode is deposited to obtain the all-perovskite tandem solar cell based on narrow bandgap buried interface modification.

2. The preparation method according to claim 1, characterized in that, In step S3, the wide bandwidth FA 0.8 MA 0.1 Cs 0.1 Pb(I 0.6 Br 0.4 The preparation method of perovskite precursor materials includes the following steps: Formamidinium iodide, methylamine iodide, cesium iodide, lead iodide, and lead bromide are dissolved in a solvent to form a perovskite precursor solution with a concentration of 0.8-1.4 mmol / mL. After stirring and reacting, a wide-bandgap perovskite precursor material is obtained. The preparation method of the narrow bandgap perovskite precursor material in step S9 includes the following steps: A perovskite precursor solution with a concentration of 1.5-2.0 mmol / mL is formed by dissolving formamidine iodide, cesium iodide, lead iodide, stannous iodide, stannous fluoride, and formamidine acetate in a solvent. After stirring and reacting, a narrow bandgap perovskite precursor material is obtained.

3. The preparation method according to claim 1, characterized in that, The preparation method of the mixed solution of lead iodide and hydrazine sulfate in step S8 includes the following steps: Dissolve 2-10 parts by weight of lead iodide and 0.5-2 parts by weight of hydrazine sulfate in N,N-dimethylformamide solvent, and stir at 30-80°C for 1-5 hours until completely dissolved to obtain the mixed solution of lead iodide and hydrazine sulfate.

4. The preparation method according to claim 1, characterized in that, In step S8, the mass ratio of lead iodide to hydrazine sulfate is (1-16):

1.

5. The preparation method according to claim 1, characterized in that, In step S3, the perovskite precursor material is coated in two steps using a spin coating method: first, the material is spin coated at a first speed for a first time period, and then at a second speed for a second time period. The first speed is 900~1200 rpm, and the first time period is 8~13 seconds; the second speed is 3000~6000 rpm, and the second time period is 30~50 seconds. In step S9, the perovskite precursor material is deposited using a one-step solvent-free spin coating method, with an annealing temperature of 100-120℃ and a processing time of 10-20 minutes.

6. The preparation method according to claim 1, characterized in that, The hole transport material in step S2 is a MeO-4PACz solution; In step S7, the hole transport material is PEDOT:PSS / NiO. X .

7. The preparation method according to claim 1, characterized in that, The electron transport material in steps S4 and S10 is PCBM.

8. A fully perovskite tandem solar cell, characterized in that, It is prepared by the preparation method according to any one of claims 1-7.

9. The application of the all-perovskite tandem solar cell according to claim 8 in the field of optoelectronics.

10. An optoelectronic device, characterized in that, Includes the embedded interface modification layer described in step S8 of claim 1.

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