Perovskite solar cell treated by using structural characteristics of graphdiyne

Abstract

The present application belongs to the field of photovoltaic material manufacturing, and particularly relates to a perovskite solar cell treated by using the structural characteristics of graphdiyne. The solar cell comprises, from bottom to top, a transparent conductive substrate, a crystalline graphdiyne modified electron transport layer, a perovskite active layer, a hole transport layer and a metal counter electrode. The crystalline graphdiyne modified electron transport layer is modified by using crystalline graphdiyne on the surface of the electron transport layer, which serves as a template to induce the growth of perovskite crystals and realize the homogenization of film stress. This is conducive to the preparation of high-performance and high-stability perovskite solar cells. Meanwhile, the present application has low production cost and simple preparation method, and is more conducive to actual production.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of photovoltaic material manufacturing, and particularly relates to a perovskite solar cell treated by using the structural characteristics of graphdiyne. BACKGROUND

[0002] In recent years, solar cells with perovskite (PSC) as a light-absorbing layer have experienced unprecedented development, which can be comparable to most commercial photovoltaic cells. The overall high-quality perovskite thin film is a prerequisite for high-efficiency perovskite solar cells (PSCs). However, during the nucleation and growth of perovskite, the inevitable aperiodic growth leads to internal strain of the perovskite film. The strain in halide perovskite often leads to the formation of a large number of defects, resulting in non-radiative recombination loss. The beginning of the relatively disordered epitaxial growth at the buried interface is an important reason for the non-uniform crystallization of the perovskite film. The effectiveness of stress release can be improved by improving the buried interface. Therefore, in order to prepare high-quality perovskite films, the strain engineering of the buried interface is crucial for developing effective regulation strategies.

[0003] Using various modified materials to adjust the interface engineering of the buried interface has been proved to be an effective strategy to release the internal strain of the perovskite film. Carbon materials and their derivatives, such as carbon nanotubes, fullerenes, graphene and graphdiyne, have been repeatedly reported. Among them, graphdiyne (GDY) is a sp and sp 2 Co-hybridized carbon allotropes have become a new star due to their good electrical conductivity and strong chemical reactivity, and have been widely used in PSCs. In recent years, functionalized graphdiynes with excellent heteroatom characteristics (such as chloro-substituted graphdiynes, triazine graphdiynes, nitrogen-doped graphdiynes, and oxidized graphdiynes) have shown extraordinary optimization effects in improving perovskite crystallinity and interface transport performance. However, all the reported multifunctional graphdiynes are prepared by a top-down strategy, which introduces heteroatoms at the cost of partial acetylene bond rupture, leading to structural disorder and poor crystallization. So far, there is no work on modifying the buried interface by using the crystal structure characteristics of graphdiyne to prepare high-quality thin films. Therefore, expanding the application of the crystal structure of materials, and exploring the formation mechanism of uniform films behind the improvement of device performance have guiding significance for the subsequent application of graphdiyne in PSCs. SUMMARY

[0004] The application aims to provide a perovskite solar cell treated by using the structural characteristics of crystalline graphdiyne materials.

[0005] To achieve the above-mentioned purpose, the technical scheme adopted by the application is:

[0006] A perovskite solar cell processed by using the structural characteristics of crystalline graphdiyne material, from bottom to top, comprises a transparent conductive substrate, a crystalline graphdiyne modified electron transport layer, a perovskite active layer, a hole transport layer and a metal counter electrode; wherein the crystalline graphdiyne modified electron transport layer is modified on the surface of the electron transport layer by using crystalline graphdiyne as a "template" to induce the growth of perovskite crystals, so as to realize the homogenization of film stress. On this basis, the quality and electron transport capacity of the perovskite film are improved. By inhibiting the non-radiative recombination caused by defects and improving the charge extraction capacity, the photoelectric performance and stability of the device are effectively improved.

[0007] The crystalline graphdiyne modified electron transport layer is obtained by spin coating a crystalline graphdiyne dispersion on the electron transport layer and annealing the obtained product.

[0008] By using the lattice matching characteristics, crystalline thiophene graphdiyne (SGDY) is successfully introduced into the buried bottom interface as a functional lattice template. The regular growth of perovskite crystals induced by the thiophene graphdiyne (SGDY) template is conducive to relieving the excessive compressive stress caused by lattice mismatch, and finally realizes the homogenization of the internal stress of the film.

[0009] The spin coating conditions are: spin coating at 3500 rpm for 40-50 s, and then annealing at 100℃ for 5-10 min.

[0010] The crystalline graphdiyne dispersion is obtained by using anhydrous ethanol to dilute and disperse the crystalline thiophene graphdiyne after cell disruption treatment.

[0011] The preparation method of the crystalline thiophene graphdiyne is as follows:

[0012] (1) In a solvent, tetra(thiomethyl ethynyl) thiophene is obtained by using tetra(thiomethyl ethynyl) thiophene through Sonogashira coupling reaction, coupling trimethyl ethynyl silicon, using bis(triphenylphosphine) palladium dichloride and cuprous iodide as catalysts;

[0013] (2) Tetraethynyl thiophene is obtained by using tetrabutylammonium fluoride in tetrahydrofuran solvent under argon atmosphere in the dark;

[0014] (3) Tetraethynyl thiophene is added to pyridine solution, using copper sheet as catalyst and template, dropwise added to the pyridine containing copper sheet under argon atmosphere in the dark, and heated to 90-110℃ for polymerization;

[0015] (4) The product on the copper sheet is washed with acetone, 3M hydrochloric acid and anhydrous ethanol in sequence to obtain the final crystalline thiophene graphdiyne.

[0016] The electron transport layer is a tin oxide electron transport layer, and the preparation method of the tin oxide electron transport layer is as follows:

[0017] (1) SnO2 precursor solution preparation: dilute the SnO2 colloid solution, the dilution ratio is SnO2:H2O = 1:3 (v:v), and then ultrasonic dispersion is performed on the dilution solution to obtain the SnO2 precursor solution;

[0018] (2) Transparent conductive substrate: the transparent conductive substrate is sequentially subjected to ultrasonic treatment with glass detergent, deionized water, acetone and isopropyl alcohol, and then is blown dry with nitrogen, and is subjected to plasma treatment.

[0019] (3) SnO2 electron transport layer preparation: the prepared SnO2 precursor solution in step (1) is spin-coated onto the glass substrate in step (2) on a film applicator, and annealing is performed to obtain the SnO2 electron transport layer.

[0020] The preparation method of the perovskite solar cell processed by the structural characteristics of the crystalline graphdiyne material is as follows:

[0021] Step (1): the transparent conductive substrate is sequentially subjected to ultrasonic treatment with glass detergent, deionized water, acetone and isopropyl alcohol for 15-20 min, and then is blown dry with nitrogen, and is subjected to plasma treatment for 15-20 min.

[0022] Step (2): the SnO2 precursor solution is spin-coated onto the glass substrate in step (1) at a rotation speed of 3500 rpm for 30-40 s, and is annealed at 150°C for 20-30 min, and then is cooled to room temperature for standby use.

[0023] Step (3): the crystalline graphdiyne dispersion liquid is spin-coated onto the SnO2 electron transport layer in step (2) at a rotation speed of 3500 rpm for 30-40 s, and is annealed at 100°C for 5-10 min.

[0024] Step (4): the perovskite layer is deposited by spin-coating the perovskite precursor solution, the spin-coating is performed at a rotation speed of 5000 rpm for 40-60 s, 200 μL of ethyl acetate anti-solvent is injected at the 10th-15th second, the perovskite precursor solution is formed into a film, and then the active layer is obtained by annealing at 100°C for 50-60 min; and step (5): the passivation layer precursor solution is spin-coated on the perovskite active layer in step (4) at a rotation speed of 4000 rpm for 20-30 s.

[0025] Step (6): the hole transport layer is obtained by spin-coating the Spiro-OMeTAD precursor solution at a rotation speed of 4000 rpm for 30-40 s, and the perovskite device is aged after spin-coating.

[0026] Step (7): the perovskite device aged in step (6) is sequentially subjected to evaporation of molybdenum oxide and silver electrodes to obtain the perovskite solar cell processed by the structural characteristics of the crystalline graphdiyne material.

[0027] The perovskite precursor solution in step (4) is obtained by adding cesium iodide (CsI), methylamine chloride (MACl), methylamine iodide (MAI), formamidine iodide (FAI), and lead iodide (PbI2) in a molar ratio of 0.05:0.20:0.10:1.40:1.68 to a mixed solution of DMF and DMSO (DMF:DMSO=4:1, v:v).

[0028] The passivation layer precursor solution in step (5) is an isopropanol solution of phenylethylammonium iodide (PEAI).

[0029] The Spiro-OMeTAD precursor solution in step (6) uses chlorobenzene as a solvent, and each 1000 μL of solvent contains 80-100 mg of Spiro-OMeTAD powder, 30-40 μL of tetra-tert-butylpyridine solution, and 40-50 μL of acetonitrile solution containing lithium bis-trifluoromethanesulfonyl imide.

[0030] Principle of the invention:

[0031] This invention introduces highly crystalline thiophene graphene (SGDY) into the buried interface to control film strain. This is the first time that the structural properties of functionalized SGDY have been utilized, using crystalline SGDY as a "template" to induce perovskite crystal growth. Lattice matching between crystalline SGDY and the perovskite crystal homogenizes the internal stress of the film. This improves the quality of the perovskite film while also facilitating charge extraction and transfer at the interface, ultimately enabling the fabrication of high-performance, highly stable perovskite solar cell devices.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] (1) Based on the property that the structure of graphyne can be regulated by heteroatom functionalization, the present invention prepares crystalline thiophene graphyne through a "bottom-up" approach, avoiding the introduction of heteroatoms at the expense of breaking some acetylene bonds, and exhibiting good polymerization regularity.

[0034] (2) The thiophene graphyne of the present invention has good crystallization properties and matches the lattice parameters of perovskite (FAPbI3). Utilizing the unique structural properties of the thiophene graphyne material, it is used as an electron transport layer and interlayer modification of the perovskite active layer, acting as a "template" to induce perovskite crystal growth and release excessive stress within the film. This achieves homogenization of the internal stress of the film and improves the quality of the perovskite film.

[0035] (3) The present invention is the first to utilize the structural characteristics of graphyne materials to regulate the performance of perovskite solar cells. By taking advantage of the high lattice matching between crystalline thiophene graphyne and the perovskite 001 plane, a buried interface is introduced to induce the growth of perovskite crystals.

[0036] (4) The present invention utilizes a buried interface modification strategy and the highly lattice-matching properties of crystalline thiophene graphyne to achieve strain regulation in perovskite films. As a functional lattice template for perovskite crystals at the buried interface, it induces the growth of high-quality perovskite films and alleviates stress inhomogeneities within the films. This is beneficial for the preparation of high-performance, high-stability perovskite solar cells. Furthermore, the present invention has low production costs and a simple preparation method, making it more conducive to practical production. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 Schematic diagram of the perovskite device structure and stress release regulation mechanism in the present invention.

[0038] Figure 2 HRTEM image of crystalline SGDY and elemental mapping of C and S in the present invention (the inset is an HRTEM image of the interlayer spacing of SGDY)

[0039] Figure 3 The XRD pattern of the crystalline SGDY in the present invention and the HRTEM image of its corresponding lattice constants.

[0040] Figure 4 XRD patterns of the inventive, optimized perovskite films and crystalline SGDY, as well as the scratched, stress-free perovskite powder.

[0041] Figure 5 2D GIWAXS patterns of perovskite films optimized for the winning product and crystalline SGDY at different incident angles from 0.1° to 3.6°

[0042] Figure 6 1D GIWAXS patterns of the optimized perovskite films for the standard and crystalline SGDY in the present invention at different incident angles from 0.1° to 2°.

[0043] Figure 7 These are the top surface morphology images of the standard and crystalline SGDY-optimized perovskite film obtained by SEM and AFM in the present invention.

[0044] Figure 8 These are buried interface morphology images of the standard piece and the crystalline SGDY-optimized perovskite film obtained by SEM and AFM in the present invention.

[0045] Figure 9 Cross-sectional SEM images of the PSC device optimized for the standard sample and crystalline SGDY in this invention.

[0046] Figure 10 PL spectra and TRPL spectra of the perovskite films deposited on SnO2 and SnO2 / SGDY in the present invention.

[0047] Figure 11 JV curves of the forward and reverse scans of the target component and the crystalline SGDY optimized device of the present invention

[0048] Figure 12 The long-term stability test curves of the unpackaged standard and crystalline SGDY optimized devices in N2 atmosphere are shown. DETAILED DESCRIPTION

[0049] The present invention will be further described below with reference to the accompanying drawings and examples, but these examples do not limit the scope of the present invention.

[0050] The present invention discloses a perovskite solar cell utilizing the structural characteristics of crystalline graphyne materials. The solar cell comprises, sequentially deposited from bottom to top, a transparent conductive substrate, a crystalline graphyne-modified electron transport layer, a perovskite active layer, a hole transport layer, and a metal counter electrode. The surface of the tin oxide electron transport layer is modified with crystalline graphyne material, which is then spin-coated onto the tin oxide substrate using a dispersion of the material in ethanol after cell disruption. The perovskite light absorption layer is prepared using an organic-inorganic halide perovskite, the hole transport layer is prepared using Spiro-OMeTAD, and a metal Ag electrode serves as the counter electrode.

[0051] Example 1

[0052] Combine Figure 1 Schematic diagram of the device structure,

[0053] Step (1): A commercially purchased transparent conductive substrate was ultrasonically treated with glass detergent, deionized water, acetone, and isopropyl alcohol for 15 minutes, respectively, and then dried with nitrogen gas, and then treated with plasma for 15 minutes.

[0054] Step (2): Spin-coat the prepared tin oxide precursor solution onto the treated glass substrate on a spin coater at a speed of 3500 rpm for 30 seconds, place it on a hot plate at 150°C for annealing for 30 minutes, and then cool it to room temperature for use;

[0055] The tin oxide solution is prepared by diluting a tin oxide colloidal solution (15% aqueous colloidal dispersion) at a dilution ratio of SnO2:H2O=1:3 (v:v), and ultrasonically dispersing the diluted solution for 15 minutes.

[0056] Step (3): spin-coating the crystalline graphyne dispersion onto the tin oxide electron transport layer on a spin coater at 3500 rpm for 30 seconds, and then annealing at 100°C for 5 minutes;

[0057] The crystalline graphyne dispersion is obtained by disintegrating crystalline thiophene graphyne into cells and then diluting and dispersing the cells using anhydrous ethanol.

[0058] Crystalline thiophene graphene (GD) is prepared by adding tetrabromothiophene (1 g, 2.5 mmol) to triethylamine (60 mL) and stirring to dissolve. Under an Ar atmosphere, trimethylsilyl acetylene (1.47 g, 15 mmol), bis(triphenylphosphine)palladium dichloride (53 mg, 0.075 mmol), and cuprous iodide (14 mg, 0.075 mmol) are added. The reaction is heated at 80°C and stirred for 24 hours. After the reaction is complete, water is added to the mixture, and the mixture is extracted with dichloromethane. After drying over anhydrous sodium sulfate, the solvent is evaporated to dryness. Purification by silica gel column chromatography yields a pale yellow powder, tetrakis(trimethylethynyl)thiophene. Under a dark Ar atmosphere, 2,3,4,5-tetrakis[(trimethylsilyl)ethynyl]thiophene (20 mg, 0.044 mmol) was dissolved in tetrahydrofuran (THF) (30 ml), and 0.25 ml of tetrabutylammonium fluoride (TBAF) (1 M THF, 0.25 mmol) was added. The reaction mixture was stirred at 8°C for 10 min, then washed with saturated brine and ethyl acetate, dried over anhydrous sodium sulfate, and the solvent evaporated under vacuum to obtain tetraethynylthiophene. 30 ml of pyridine was added to the tetraethynylthiophene to dissolve it. Under a dark Ar atmosphere, the solution was added dropwise to 70 ml of pyridine containing copper foil. The reaction mixture was heated at 110°C and reacted for three days before the copper foil was removed. The product on the copper foil was ultrasonically cleaned with acetone, 3 M hydrochloric acid, and anhydrous ethanol, followed by drying to obtain a black powder, which is crystalline thiophene-graphene.

[0059] Step (4): depositing a perovskite precursor solution by spin coating on the above-mentioned crystalline graphyne modified layer at a rotation speed of 5000 rpm for 40 seconds, injecting 200 μL of ethyl acetate antisolvent in the last 10 seconds to form a film of the perovskite precursor solution, and then annealing at 100°C in a glove box for 60 minutes to obtain a perovskite active layer film;

[0060] The perovskite precursor solution is prepared by adding cesium iodide (CsI), methylamine chloride (MACl), methylamine iodide (MAI), formamidine iodide (FAI), and lead iodide (PbI2) in a molar ratio of 0.05:0.20:0.10:1.40:1.68 to a mixed solution of DMF and DMSO (DMF:DMSO=4:1, v:v), and stirring overnight to obtain a perovskite precursor solution.

[0061] Step (5): Spin-coat the passivation layer precursor solution on the perovskite active layer at 4000 rpm for 20 seconds;

[0062] The passivation layer precursor solution is an isopropanol solution of phenylethylammonium iodide (PEAI) with a concentration of 2 mg / ml.

[0063] Step (6): The hole transport layer was obtained by spin coating the Spiro-OMeTAD precursor solution at 4000 rpm for 30 seconds. The spin-coated perovskite device was placed in a constant temperature and humidity drying oven and aged for 17 hours.

[0064] The Spiro-OMeTAD precursor solution uses chlorobenzene as a solvent. Each 1000 μL of solvent contains 90 mg of Spiro-OMeTAD powder, 37 μL of tetra-tert-butylpyridine solution, and 44 μL of acetonitrile solution containing lithium bis-trifluoromethanesulfonyl imide (260 mg / mL). After mixing, the mixture is continuously shaken on a vortex oscillator for 2 hours to fully dissolve the Spiro-OMeTAD precursor solution.

[0065] Step (7): Place the aged perovskite device into a mask with suitable specifications, and use a vacuum coating machine to coat the perovskite device with a thickness of at least 1×10 -7 Under the high vacuum conditions of Pa, 8nm of molybdenum oxide and 100nm of silver electrode were sequentially evaporated to obtain the prepared perovskite solar cell processed by utilizing the structural characteristics of crystalline graphyne material.

[0066] Comparative Example 1

[0067] The difference from Example 1 is that no crystalline graphyne modification layer is provided. The other steps are the same as those in Example 1, specifically:

[0068] Step (1): A commercially purchased transparent conductive substrate was ultrasonically treated with glass detergent, deionized water, acetone, and isopropyl alcohol for 15 minutes, respectively, and then dried with nitrogen gas, and then treated with plasma for 15 minutes.

[0069] Step (2): Spin-coat the prepared tin oxide precursor solution onto the treated transparent conductive substrate on a spin coater at a speed of 3500 rpm for 30 seconds, place it on a hot plate at 150°C for annealing for 30 minutes, and then cool it to room temperature for use;

[0070] The tin oxide solution is prepared by diluting a tin oxide colloidal solution (15% aqueous colloidal dispersion) at a dilution ratio of SnO2:H2O=1:3 (v:v), and ultrasonically dispersing the diluted solution for 15 minutes.

[0071] Step (3): The perovskite layer was deposited by spin coating the precursor solution at a speed of 5000 rpm for 40 seconds. 200 μL of ethyl acetate antisolvent was injected in the last 10 seconds to form a film of the perovskite precursor solution. The film was then annealed at 100°C in a glove box for 60 minutes to obtain a perovskite active layer film.

[0072] The perovskite precursor solution is prepared by adding cesium iodide (CsI), methylamine chloride (MACl), methylamine iodide (MAI), formamidine iodide (FAI), and lead iodide (PbI2) in a molar ratio of 0.05:0.20:0.10:1.40:1.68 to a mixed solution of DMF and DMSO (DMF:DMSO=4:1, v:v), and stirring overnight to obtain a perovskite precursor solution.

[0073] Step (4): Spin-coat the passivation layer precursor solution on the perovskite active layer at 4000 rpm for 20 seconds;

[0074] The passivation layer precursor solution is an isopropanol solution of phenylethylammonium iodide (PEAI) with a concentration of 2 mg / ml.

[0075] Step (5): The hole transport layer was obtained by spin coating the Spiro-OMeTAD precursor solution at 4000 rpm for 30 seconds. The spin-coated perovskite device was placed in a constant temperature and humidity drying oven and aged for 17 hours.

[0076] The Spiro-OMeTAD precursor solution uses chlorobenzene as a solvent. Each 1000 μL of solvent contains 90 mg of Spiro-OMeTAD powder, 37 μL of tetra-tert-butylpyridine solution, and 44 μL of acetonitrile solution containing lithium bis-trifluoromethanesulfonyl imide (260 mg / mL). After mixing, the mixture is continuously shaken on a vortex oscillator for 2 hours to fully dissolve the Spiro-OMeTAD precursor solution.

[0077] Step (6): Place the aged perovskite device into a mask with suitable specifications, and use a vacuum coating machine to coat the perovskite device with a thickness of at least 1×10 -7 Under the high vacuum conditions of Pa, 8nm of molybdenum oxide and 100nm of silver electrode were evaporated in sequence to obtain the prepared perovskite solar cell.

[0078] The above embodiments and comparative examples were subjected to performance tests.

[0079] like Figure 2 As shown, the HRTEM image of the thiophene graphyne material shows curved fringes with a lattice spacing of 0.38 nm, which can be attributed to the interlayer spacing of thiophene graphyne (SGDY) and is consistent with the characteristics of graphyne-based materials. In addition, the uniform distribution of carbon and sulfur elements in SGDY corresponds well to the elemental map, confirming the successful preparation of the material.

[0080] pass Figure 3 The structural characteristics of SGDY were studied by HRTEM and XRD pattern measurements, such as Figure 3As shown, the SGDY material prepared by this method exhibits a highly crystalline state. The peak positions in the XRD pattern were calculated according to Bragg's law (q = 2π / d), and the resulting diffraction spacings of different crystal planes all corresponded well to the HRTEM image. Simultaneously, the diffraction spots obtained by fast Fourier transform of the corresponding selected areas confirmed the material's hexagonal lattice structure and well defined the structural information of the crystalline SGDY. Most importantly, the planar d-spacing value of the crystal plane corresponding to the peak at 14.74° is 0.60nm, which, as one of the dominant crystal planes, perfectly matches the (001) crystal plane of the perovskite (d = 0.632nm).

[0081] like Figure 4 As shown, the XRD peak (001) of the standard perovskite film shifts toward higher diffraction angles relative to the scratched, stress-free perovskite powder, demonstrating that the film is subjected to significant compressive strain. Based on this, the present invention introduces a crystalline SGDY functional lattice template into the buried interface. Its lattice parameters, with high lattice matching, provide a more orderly initiation for the three-dimensional periodic epitaxial growth of the perovskite lattice. With the optimization of the crystalline SGDY, the peak position of the (001) plane shifts to lower angles, demonstrating that the compressive strain is effectively alleviated.

[0082] Grazing-incidence wide-angle X-ray scattering (GIWAXS) was characterized to investigate the residual strain release in various dimensions. A range of incident angles from 0.1° to 3.6° was used to investigate the depth-dependent microstructure of the film, and the corresponding 1D GIWAXS patterns were obtained by orientation integration of the 2D patterns. Figure 5 As shown in Figure 2, the perovskite grows along the vertical orientation. After introducing SGDY optimization, the overall scattering intensity is significantly improved without affecting the dominant crystal orientation, indicating that the overall film crystallinity is improved, which is in good correspondence with the XRD results. Figure 6As shown in the figure, the in-plane (qxy) and out-of-plane (qz) diffraction peaks were further extracted. The in-plane direction is parallel to the substrate, reflecting the (010) crystal plane; the out-of-plane direction is perpendicular to the substrate, reflecting the (001) crystal plane. In the in-plane direction, as the incident angle increases, the peak shifts to the right and the lattice constant decreases, reflecting an increase in compressive strain. This is caused by the higher compressive strain caused by the substrate restricting crystal growth. As the crystal gradually grows upward, the deformation freedom increases, resulting in a gradient decrease in the compressive strain. Due to excessive residual stress, the deformation of the perovskite octahedral lattice causes the lattice to gradually expand from the top surface to the interior of the film in the out-of-plane direction. This severe crystalline heterogeneity caused by residual stress in both the in-plane and out-of-plane directions is the culprit for the existence of a large number of structural defects, affecting the overall perovskite film quality. After the introduction of crystalline SGDY at the buried interface, consistent peaks are shown at different film depths, both in the in-plane and out-of-plane directions, indicating that lattice distortion in all dimensions has disappeared. The crystalline material serving as the functional substrate templating induces the subsequent perovskite crystal growth, adjusting the stress inside the entire film to achieve uniform growth of the perovskite crystal.

[0083] To check the crystallization state of the perovskite film, the standard and crystalline SGDY optimized film were directly observed from all directions using scanning electron microscopy (SEM) and atomic force microscopy (AFM). Figure 7 As shown in the figure, the upper surface morphology of the perovskite film of the standard piece clearly shows wrinkles due to extrusion, which is caused by strong compressive strain. After the stress is eliminated, the upper surface morphology image is smooth and flat, which is consistent with the AFM results. In addition, after the introduction of crystalline SGDY adjustment, the grain size increases and is evenly distributed, while the residual PbI2 clusters decrease. The exposed buried interface morphology can be intuitively found that the crystalline SGDY optimization effectively reduces the pinhole-like gaps and the film is more dense ( Figure 8 The dense perovskite film exhibits high hydrophobicity, which is the key to improving device stability. Cross-sectional SEM image of the perovskite film ( Figure 9 ) also showed an improvement in the vertical growth and quality of the overall thin film crystals, which is corroborated by the increase in the intensity of the XRD characteristic peaks. The reason for achieving the above performance is that the stress homogenization achieved after lattice matching regulates the growth of perovskite crystals. The fewer grain boundaries and pinholes in the optimized film, the less non-radiative recombination losses caused by structural defects, which is beneficial to reducing the Voc loss in the PSC. At the same time, the flat morphology at the buried interface provides a good foundation for the subsequent deposition of the perovskite layer, which is conducive to better longitudinal orderly growth of the crystal.

[0084] To demonstrate the effect of crystalline SGDY on the electron extraction and transfer process between SnO2 and perovskite, steady-state photoluminescence (PL) and time-resolved photoluminescence (TRPL) were characterized for perovskite films deposited on SnO and SnO / thiophene Graphene substrates. Figure 10 As shown, the optimized film produces a stronger PL quenching effect, indicating a higher electron extraction capability. Furthermore, the TRPL spectra of the two perovskite films were characterized and fitted using a biexponential decay equation. The optimized crystalline SGDY exhibits a shorter decay time of 14.22 ns, compared to 26.52 ns for the tin oxide / perovskite film, indicating a stronger electron extraction capability, consistent with the PL results.

[0085] Further performance and stability tests were conducted on perovskite solar cell devices under simulated sunlight. A planar heterojunction solar cell with a FTO / SnO2 / perovskite / Spiro OMeTAD / MoO3 / Ag structure was fabricated. By optimizing the buried crystalline SGDY modification concentration, optimal photovoltaic performance was achieved, with a significant improvement in PCE. Figure 11 The current density versus voltage (JV) curve of the optimal PSC is shown. The optimized device shows a reduced hysteresis phenomenon. The hysteresis index (HI) is reduced from 3.42% to 2.69%. Stability is one of the important criteria for evaluating device performance. The present invention tests the PCE data of the unpackaged device stored in a nitrogen atmosphere at room temperature for a long time. Figure 12 It can be seen that after 2000h, the PCE value of the optimized device still remains above 90% of the initial value, indicating that the regularly grown perovskite crystals caused by lattice stress homogeneity are the key reason for the improved stability.

[0086] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A perovskite solar cell utilizing the structural characteristics of crystalline graphyne material, characterized in that: The solar cell consists of a transparent conductive substrate, a crystalline gydne-modified electron transport layer, a perovskite active layer, a hole transport layer, and a metal counter electrode, from bottom to top. The crystalline gydne-modified electron transport layer is modified with crystalline gydne on the surface of the electron transport layer, which acts as a "template" to induce perovskite crystal growth and achieve film stress homogenization. The crystalline graphyne modified electron transport layer is obtained by spin coating a crystalline graphyne dispersion on the electron transport layer and annealing; The crystalline graphyne dispersion is obtained by diluting and dispersing crystalline thiophene graphyne with anhydrous ethanol after cell disruption.

2. The perovskite solar cell utilizing the structural characteristics of crystalline graphyne material according to claim 1, characterized in that: The spin coating conditions are as follows: spin coating at a speed of 3500 rpm for 30-40 seconds and then annealing at 100° C. for 5-10 minutes.

3. The perovskite solar cell utilizing the structural characteristics of crystalline graphyne material according to claim 1, characterized in that: The preparation method of crystalline thiophene graphene is: In a solvent, tetrabromothiophene is coupled with trimethylethynylsilane via a Sonogashira coupling reaction using bis(triphenylphosphine)palladium dichloride and cuprous iodide as catalysts to obtain tetrakis(trimethylethynyl)thiophene; Tetrakis(trimethylethynyl)thiophene is treated with tetrabutylammonium fluoride in tetrahydrofuran solvent under a light-proof argon atmosphere and stirred to obtain tetraethynylthiophene; Pyridine was added to tetraethynylthiophene to dissolve it, and a copper sheet was used as a catalyst and template. In the dark under an argon atmosphere, the mixture was added dropwise to the pyridine containing the copper sheet, and heated to 90°C-110°C for polymerization. The product on the copper sheet was washed with acetone, 3M hydrochloric acid, and anhydrous ethanol in sequence to obtain the final crystalline thiophene graphyne.

4. The perovskite solar cell utilizing the structural characteristics of crystalline graphyne material according to claim 1, characterized in that: The electron transport layer is a tin oxide electron transport layer, and the preparation method of the tin oxide electron transport layer is as follows: (1) Preparation of tin oxide precursor solution: dilute the tin oxide colloidal solution to a volume ratio of SnO2:H2O=1:3, and ultrasonically disperse the diluted solution to obtain a tin oxide precursor solution; (2) Transparent conductive substrate: The transparent conductive substrate was ultrasonically treated with glass detergent, deionized water, acetone, and isopropyl alcohol, followed by drying with nitrogen and plasma treatment. (3) Preparation of tin oxide electron transport layer: The prepared tin oxide precursor solution of step (1) is spin-coated onto the glass substrate of step (2) on a coating machine and annealed.

5. The perovskite solar cell utilizing the structural characteristics of crystalline graphyne material according to claim 1, characterized in that: Step (1) The transparent conductive substrate is ultrasonically treated with glass detergent, deionized water, acetone, and isopropyl alcohol for 15-20 minutes, blown dry with nitrogen, and then treated with plasma for 15-20 minutes; Step (2) spin-coating the tin oxide precursor solution onto the glass substrate of step (1) at a rotation speed of 3500 rpm for 30-40 seconds, annealing at 150° C. for 20-30 minutes, and then cooling to room temperature for use; Step (3) Spin-coating the crystalline graphyne dispersion onto the tin oxide electron transport layer of step (2) at a speed of 3500 rpm for 30-40 seconds, and annealing at 100°C for 5-10 minutes; Step (4) The perovskite layer is deposited by spin coating the perovskite precursor solution at a speed of 5000 rpm for 40-60 seconds, and 200 μL of ethyl acetate antisolvent is injected in the last 10-15 seconds to form a film of the perovskite precursor solution, and then annealed at 100°C for 50-60 minutes to obtain an active layer; Step (5) spin-coating the passivation layer precursor solution on the perovskite active layer in step (4) at 4000 rpm for 20-30 seconds; Step (6) The hole transport layer is obtained by spin coating the Spiro-OMeTAD precursor solution at a speed of 4000 rpm for 30-40 seconds. The perovskite device is aged after spin coating. Step (7) sequentially vapor-deposit molybdenum oxide and silver electrodes on the perovskite device that has been aged in step (6), thereby obtaining a perovskite solar cell processed using the structural characteristics of the crystalline graphyne material.

6. The perovskite solar cell utilizing the structural characteristics of crystalline graphyne material according to claim 5, characterized in that: The perovskite precursor solution in step (4) is obtained by adding cesium iodide (CsI), methylamine chloride (MACl), methylamine iodide (MAI), formamidine iodide (FAI), and lead iodide (PbI2) in a molar ratio of 0.05:0.20:0.10:1.40:1.68 to a mixed solution of DMF and DMSO, and the volume ratio of DMF to DMSO is 4:

1.

7. The perovskite solar cell utilizing the structural characteristics of crystalline graphyne material according to claim 5, characterized in that: The passivation layer precursor solution in step (5) is an isopropanol solution of phenylethylammonium iodide (PEAI).

8. The perovskite solar cell utilizing the structural characteristics of crystalline graphyne material according to claim 5, characterized in that: The Spiro-OMeTAD precursor solution in step (6) uses chlorobenzene as a solvent, and each 1000 μL of solvent contains 80-100 mg of Spiro-OMeTAD powder, 30-40 μL of tetra-tert-butylpyridine solution, and 40-50 μL of acetonitrile solution containing lithium bis-trifluoromethanesulfonyl imide.

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