High-stability perovskite solar cell and preparation method thereof

Abstract

The invention relates to a high-stability perovskite solar cell and a preparation method thereof, and relates to the technical field of novel solar cells, the structure of the perovskite solar cell is an upright structure, and the perovskite solar cell sequentially comprises a conductive glass electrode layer, an electron transport layer, a perovskite layer, a hole transport layer and a counter electrode layer from bottom to top; wherein an interface bridging layer is also arranged between the electron transport layer and the perovskite layer. Non-radiative recombination of photon-generated carriers at the interface is inhibited through interface modification and defect passivation, and the number of defects is reduced, so that the transmission efficiency of the carriers is improved, and finally the efficiency and stability of the PSCs are improved.

Description

Technical Field

[0001] This invention relates to the field of novel solar cell technology, and in particular to a highly stable perovskite solar cell and its preparation method. Background Technology

[0002] Sustainable development achieves long-term balanced economic, social, and ecological development through environmental protection, the promotion of clean energy, and the rational utilization of clean resources. Among these clean energy sources, solar energy, with its vast reserves, possesses strong market competitiveness. The conversion and utilization of solar energy, especially its conversion into electricity through solar cells, is becoming a crucial pathway to realizing this potential. Among various solar cell technologies, perovskite solar cells (PSCs) have become a cutting-edge research focus due to their simple structure, excellent solution processing performance, low manufacturing cost, and outstanding photoelectric conversion efficiency. Thanks to the excellent photoelectric performance of organic-inorganic hybrid perovskite materials, the certified power conversion efficiency of single-junction PSCs has now exceeded 26%. However, the path to improving the performance of PSCs is not without its challenges.

[0003] In perovskite solar cells (PSCs), whether planar or mesoporous, there are four key interfaces: the conductive glass electrode layer / electron transport layer, the electron transport layer / perovskite layer, the perovskite layer / hole transport layer, and the hole transport layer / counter electrode layer. These interfaces affect the device's efficiency and long-term stability. Interface characteristics directly affect carrier extraction and transport efficiency, the energy level arrangement at the interface determines carrier recombination behavior, and deep-level defects at the interface lead to severe charge accumulation and nonradiative recombination, thus significantly reducing device performance. In particular, nonradiative recombination at the electron transport layer-perovskite layer interface leads to significant photogenerated carrier loss, thus affecting device efficiency and stability. Therefore, there is an urgent need to develop a novel perovskite solar cell to improve its efficiency and stability. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a highly stable perovskite solar cell and its fabrication method. This application suppresses nonradiative recombination of photogenerated carriers at the interface through interface modification and defect passivation, reducing the number of defects and thereby improving carrier transport efficiency, ultimately enhancing the efficiency and stability of the PSCs.

[0005] In a first aspect, the present invention provides a highly stable perovskite solar cell, wherein the perovskite solar cell has an upright structure, comprising, from bottom to top, a conductive glass electrode layer, an electron transport layer, a perovskite layer, a hole transport layer, and a counter electrode layer; wherein the conductive glass electrode layer is made of an FTO glass substrate or an ITO glass substrate; the counter electrode layer is made of one or more of Al, Ag, Au, Mo, and Cr, with a thickness of 60-120 nm; the electron transport layer is a SnO2 layer with a thickness of 10-120 nm; and the perovskite in the perovskite layer is a semiconductor compound with an ABX3 structure, wherein A is NH=CHNH. 3+ CH3NH 3+ or Cs + B is Pb 2+ or Sn 2+ ;X is I - Cl - or Br - The thickness is 300-700nm; the hole transport layer is made of organic hole material with a thickness of 20-120nm; an interface bridging layer with a thickness of 2-10nm is also provided between the electron transport layer and the perovskite layer.

[0006] In the above technical solution, the interface bridging layer can effectively suppress the energy loss caused by non-radiative recombination, improve the interface stability, enhance the electron mobility and conduction band position of SnO2, promote the extraction of interface charge and induce the growth of large-grain perovskite, and improve the overall battery stability.

[0007] Optionally, the material of the interface bridging layer includes tetracarboxyporphyrin and zinc acetate in a molar ratio of 1:1-1.2.

[0008] In the above technical solution, the porphyrin units in the tetracarboxyporphyrin are oriented to form a vertical electron transport channel from SnO2 to the perovskite layer, greatly promoting the extraction and transport speed of electrons. Its four carboxyl groups (-COOH) are used to react with Zn... 2+ Coordination occurs, and one of the carboxyl groups can form a strong coordination bond with the hydroxyl group (-OH) on the SnO2 surface, enabling in-situ anchoring and growth of the interfacial bridging layer material on SnO2. 2+ Coordination strongly passivates lead defects in the perovskite layer.

[0009] Zinc acetate with Zn 2+ It readily coordinates with carboxylic acids to form stable Zn-O bonds. Simultaneously, it can also react with I₂ in perovskites. - A weak interaction occurs, which helps to passivate halogen vacancies.

[0010] Optionally, the preparation steps of the interface bridging layer material are as follows: weigh tetracarboxyporphyrin and zinc acetate and dissolve them in a mixed solvent of DMF and ethanol with a volume ratio of 1:1, and stir at 45-55℃ for 25-35 min to obtain the interface bridging layer material.

[0011] In the above technical solution, DMF is used to dissolve tetracarboxyporphyrin and zinc acetate, and ethanol is used to adjust the solvent polarity and control the reaction rate.

[0012] In solution, and in mixed solutions, the carboxyl group of tetracarboxyporphyrin has begun to react with Zn. 2+ Initial coordination occurs, forming small clusters that serve as seed crystals for subsequent epitaxial growth on the substrate. The hydroxyl groups (-OH) on the SnO2 surface deprotonate a carboxyl group on the tetracarboxyporphyrin ligand in the solution, forming a coordinate bond. This firmly anchors the tetracarboxyporphyrin molecule to the SnO2 surface. The surface tetracarboxyporphyrin molecule becomes a nucleation site, and the Zn in the solution... 2+ The carboxyl groups of other tetracarboxyporphyrin molecules continue to coordinate, and the surface-anchored molecules serve as seed crystals to grow thin layers vertically and in an orderly manner.

[0013] Optionally, the hole transport layer is composed of a homogeneous composite of 4,4'-di-tert-butyl-2,2'-bipyridine and an undoped organic hole material in a mass ratio of 1:20-50, wherein the organic hole material is any one of Spiro-OMeTAD, poly-TPD, copper phthalocyanine, nickel phthalocyanine, poly(triarylamine), and poly(3-hexylthiophene).

[0014] In the aforementioned technical solutions, without chemical dopants, the organic hole material itself has relatively low hole mobility and conductivity, leading to increased series resistance and potentially lower fill factor and short-circuit current compared to doped devices. The two nitrogen atoms in the bipyridine group possess lone pairs of electrons, which can interact with uncoordinated Pb atoms on the perovskite surface. 2+The formation of stable five-membered ring chelates demonstrates a stronger and more stable passivation effect than single amino or carboxyl groups. This effectively compensates for lead-related defects on the perovskite surface, significantly reducing interfacial nonradiative recombination at its source, thereby improving the open-circuit voltage of the device. After the 4,4'-di-tert-butyl-2,2'-bipyridine molecule is anchored on the perovskite surface, the extended tert-butyl groups create small, nanoscale physical spaces between the perovskite layer and the hole transport layer. This helps release interfacial stress and improves mechanical stability. The tert-butyl group is a strongly hydrophobic organic group, exhibiting excellent compatibility with subsequently spin-coated organic hole transport materials. It improves the wettability of the hole transport layer material on the perovskite, resulting in a more uniform and dense film. Therefore, 4,4'-di-tert-butyl-2,2'-bipyridine can significantly improve interfacial contact characteristics, suppress energy loss caused by nonradiative recombination, and enhance the perovskite crystal quality and carrier transport efficiency.

[0015] Optionally, the preparation steps of the hole transport layer material are as follows: dissolve the undoped organic hole material in anhydrous chlorobenzene, stir thoroughly until completely dissolved to form a clear solution with a concentration of 70-75 mg / mL, add 4,4'-di-tert-butyl-2,2'-bipyridine to the clear solution, stir for 30-40 min to obtain a composite solution, i.e., the hole transport layer material.

[0016] In the above technical solution, 4,4'-di-tert-butyl-2,2'-bipyridine molecules are uniformly dispersed in a chlorobenzene solution of an organic vacuolated material. At this point, there is no Li in the solution. + The dopant competes for coordination with 4,4'-di-tert-butyl-2,2'-bipyridine, and all bipyridine sites in the 4,4'-di-tert-butyl-2,2'-bipyridine molecule can interact with the perovskite surface. Because there is no hygroscopic lithium salt, the solution stability is higher. 4,4'-di-tert-butyl-2,2'-bipyridine maintains a high open-circuit voltage by strongly passivating and minimizing interfacial recombination losses.

[0017] Secondly, the present invention provides a method for preparing a highly stable perovskite solar cell, the method comprising the following steps: (1) Preparation of electron transport layer: SnO2 solution was spin-coated onto a clean glass substrate using a solution method at a spin speed of 3000-4000 rpm. After spin-coating, the substrate was annealed at 150℃ for 30 min and then naturally cooled to obtain the electron transport layer. (2) Preparation of interface bridging layer: Spin-coating the interface bridging layer material onto the surface of the electron transport layer at 3500-4500 rpm for 25-35s, annealing at 100℃ for 10min, and naturally cooling to obtain the interface bridging layer. (3) Preparation of perovskite layer: The prepared perovskite precursor solution is spin-coated onto the interface bridging layer at 4000-5000 rpm. Anhydrous toluene is added dropwise as an antisolvent 5-10s after the spin-coating begins. The mixture is annealed at 100℃ for 30-45min and then naturally cooled to obtain the perovskite layer. (4) Preparation of hole transport layer: The hole transport layer material is spin-coated on the perovskite layer at a rotation speed of 4000-5000 rpm for 30-40s, and then annealed at 70℃ for 10-15min to obtain the hole transport layer. (5) Preparation of counter electrode layer: Metal is deposited on the hole transport layer under high vacuum to obtain counter electrode layer.

[0018] In the above technical solution, SnO2 serves as a highly efficient electron extraction and transport layer in the preparation step of the interface bridging layer. Molecules in the interface bridging layer material coordinate with SnO2 through carboxyl groups, passivating surface defects and acting as seed crystals to induce the optimal orientation growth of perovskite. Simultaneously, a favorable dipole layer is formed at the interface, optimizing energy level alignment.

[0019] In the perovskite layer preparation process, the antisolvent promotes rapid nucleation of perovskite, forming a dense and smooth film. The annealing process allows the crystals to grow and mature.

[0020] In the electrode layer fabrication process, high vacuum ensures the electrode remains pure and free from oxidation. The metal can form good ohmic contact with the organic hole material, ensuring effective hole collection, and can also serve as the primary conductive and protective layer. The evaporated and deposited metal can form a series connection with the underlying glass substrate through the trench at the P2 scribe line.

[0021] Thirdly, the present invention provides applications of the above-mentioned highly stable perovskite solar cell or the perovskite solar cell prepared by the above-mentioned method for preparing highly stable perovskite solar cells in the photovoltaic power generation industry, transportation industry, electronics industry, and Internet of Things industry.

[0022] In summary, the present invention has at least one of the following beneficial technical effects: 1. By introducing an interface bridging layer, energy loss caused by nonradiative recombination can be effectively suppressed, interface stability can be improved, the electron mobility and conduction band position of SnO2 can be enhanced, interface charge extraction can be promoted, and large-grain perovskite growth can be induced.

[0023] 2. By adding 4,4'-di-tert-butyl-2,2'-bipyridine to the hole transport layer, the interfacial contact characteristics can be significantly improved, the energy loss caused by non-radiative recombination can be suppressed, and the perovskite crystal quality and carrier transport efficiency can be improved.

[0024] 3. By modifying the interface and passivating defects, nonradiative recombination of photogenerated carriers at the interface is suppressed, the number of defects is reduced, thereby improving the carrier transport efficiency and ultimately improving the efficiency and stability of PSCs. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the perovskite solar cell of Embodiment 1 of the present invention.

[0026] Among them, 1-conductive glass electrode layer, 2-electron transport layer, 3-interface bridging layer, 4-perovskite layer, 5-hole transport layer, and 6-counter electrode layer. Detailed Implementation

[0027] The present invention will be further described in detail below with reference to the embodiments.

[0028] All materials used in the following examples are available for purchase on the market.

[0029] Example 1: This example provides a highly stable perovskite solar cell and its fabrication method.

[0030] like Figure 1 As shown, the perovskite solar cell #1 in this embodiment has an upright structure, consisting of a conductive glass electrode layer 1, an electron transport layer 2, an interface bridging layer 3, a perovskite layer 4, a hole transport layer 5, and a counter electrode layer 6, from bottom to top.

[0031] The preparation method includes the following steps: Preparation of S1 and electron transport layer 2: S11. Scribing the FTO glass substrate 1 with P1, ultrasonically cleaning it in Hellmanex III detergent aqueous solution, deionized water, acetone and isopropanol for 15 min each, and then drying it with nitrogen. S12. SnO2 solution was spin-coated onto the cleaned FTO glass substrate 1 using a solution method at a spin-coating speed of 3500 rpm. After spin-coating, the substrate was annealed at 150℃ for 30 min and then naturally cooled to obtain an electron transport layer 2 with a thickness of 40 nm.

[0032] S2, Fabrication of interface bridging layer 3: S21. Weigh out tetracarboxyporphyrin and zinc acetate in a molar ratio of 1:1.1 and dissolve them in a mixed solvent of DMF and ethanol in a volume ratio of 1:1. Stir at 50°C for 30 min to obtain the interface bridging layer material. S22. The above interface bridging layer material is spin-coated on the surface of electron transport layer 2 at 4000 rpm for 30s, annealed at 100℃ for 10min, and naturally cooled to obtain interface bridging layer 3 with a thickness of 5nm.

[0033] Preparation of S3 and perovskite layer 4: S31. PbI2, FAI, MABr, and PbBr2 in a molar ratio of 1.2:1:0.2:0.2 are dissolved in a mixed solvent of DMF and DMSO (volume ratio 4:1) to obtain a perovskite precursor solution with a concentration of 1.4 M. S32. The prepared perovskite precursor solution is spin-coated onto the interface bridging layer 3 at 4500 rpm. 200 μL of anhydrous toluene is added dropwise as an antisolvent 10 seconds after the spin-coating begins. The mixture is then annealed at 100°C for 40 min and allowed to cool naturally to obtain a perovskite layer 4 with a thickness of 400 nm.

[0034] S4. Preparation of hole transport layer 5: S41. Spiro-OMeTAD is dissolved in anhydrous chlorobenzene and stirred thoroughly until completely dissolved to form a clear solution with a concentration of 72.3 mg / mL. 17.5 μL of acetonitrile solution of lithium bis(trifluoromethane)sulfonylimide (concentration of 520 mg / mL) and 28.8 μL of 4-tert-butylpyridine are added to the clear solution and stirred for 40 min to obtain the hole transport layer material. S42. The hole transport layer material is spin-coated on the perovskite layer 4 at a rotation speed of 4500 rpm for 35s, and then annealed at 70°C for 12min to obtain a hole transport layer 5 with a thickness of 70nm.

[0035] S5. Preparation of electrode layer 6: After P2 scribing in the above components, at 5×10 -6 Under high vacuum, a 20 nm gold layer is first deposited, followed by an 80 nm silver layer to obtain the counter electrode layer 6. Then, after P3 scribing and edge cleaning, the upright perovskite solar cell #1 is obtained.

[0036] Example 2: This example provides a highly stable perovskite solar cell and its preparation method.

[0037] The perovskite solar cell #2 in this embodiment has an upright structure, consisting of a conductive glass electrode layer, an electron transport layer, an interface bridging layer, a perovskite layer, a hole transport layer, and a counter electrode layer from bottom to top.

[0038] The preparation method includes the following steps: S1. Fabrication of the electron transport layer: S11. Scribing the ITO glass substrate with P1, ultrasonically cleaning it in Hellmanex III detergent aqueous solution, deionized water, acetone and isopropanol for 15 min each, and then drying it with nitrogen. S12. SnO2 solution was spin-coated onto a clean ITO glass substrate using a solution method at a spin-coating speed of 3500 rpm. After spin-coating, the substrate was annealed at 150℃ for 30 min and then naturally cooled to obtain an electron transport layer with a thickness of 60 nm.

[0039] S2. Preparation of the interface bridging layer: S21. Weigh out tetracarboxyporphyrin and zinc acetate in a molar ratio of 1:1 and dissolve them in a mixed solvent of DMF and ethanol in a volume ratio of 1:1. Stir at 50°C for 30 min to obtain the interface bridging layer material. S22. Spin-coat the above interface bridging layer material onto the surface of the electron transport layer at 4000 rpm for 30s, anneal at 100℃ for 10min, and allow to cool naturally to obtain an interface bridging layer with a thickness of 10nm.

[0040] S3, Preparation of the perovskite layer: S31. PbI2, FAI, MABr, and PbBr2 in a molar ratio of 1.2:1:0.2:0.2 are dissolved in a mixed solvent of DMF and DMSO (volume ratio 4:1) to obtain a perovskite precursor solution with a concentration of 1.4 M. S32. Spin-coat the prepared perovskite precursor solution onto the interface bridging layer at 4500 rpm. Add 200 μL of anhydrous toluene as an antisolvent 10 seconds after the start of spin coating. Anneal at 100°C for 40 min and allow to cool naturally to obtain a perovskite layer with a thickness of 700 nm.

[0041] S4. Preparation of the hole transport layer: S41. Spiro-OMeTAD is dissolved in anhydrous chlorobenzene and stirred thoroughly until completely dissolved to form a clear solution with a concentration of 72.3 mg / mL. 17.5 μL of acetonitrile solution of lithium bis(trifluoromethane)sulfonylimide (concentration of 520 mg / mL) and 28.8 μL of 4-tert-butylpyridine are added to the clear solution and stirred for 40 min to obtain the hole transport layer material. S42. Spin-coat the hole transport layer material onto the perovskite layer at a rotation speed of 4500 rpm for 35s, and then anneal at 70°C for 12min to obtain a hole transport layer with a thickness of 100nm.

[0042] S5. Preparation of the electrode layer: After P2 scribing in the above components, at 5×10 -6 Under high vacuum, a 40 nm layer of silver is first deposited by evaporation, followed by a 60 nm layer of copper to obtain the counter electrode layer. Then, after P3 scribing and edge cleaning, the upright perovskite solar cell #2 is obtained.

[0043] Example 3: This example provides a highly stable perovskite solar cell and its fabrication method.

[0044] The perovskite solar cell #3 in this embodiment has an upright structure, consisting of a conductive glass electrode layer, an electron transport layer, an interface bridging layer, a perovskite layer, a hole transport layer, and a counter electrode layer from bottom to top.

[0045] The preparation method includes the following steps: S1. Fabrication of the electron transport layer: S11. Scribing the FTO glass substrate with P1, ultrasonically cleaning it in Hellmanex III detergent aqueous solution, deionized water, acetone and isopropanol for 15 min each, and then drying it with nitrogen. S12. SnO2 solution was spin-coated onto a clean FTO glass substrate using a solution method at a spin-coating speed of 3500 rpm. After spin-coating, the substrate was annealed at 150℃ for 30 min and then naturally cooled to obtain an electron transport layer with a thickness of 100 nm.

[0046] S2. Preparation of the interface bridging layer: S21. Weigh out tetracarboxyporphyrin and zinc acetate in a molar ratio of 1:1.2 and dissolve them in a mixed solvent of DMF and ethanol in a volume ratio of 1:1. Stir at 50°C for 30 min to obtain the interface bridging layer material. S22. Spin-coat the above interface bridging layer material onto the surface of the electron transport layer at 4000 rpm for 30s, anneal at 100℃ for 10min, and allow to cool naturally to obtain an interface bridging layer with a thickness of 2nm.

[0047] S3, Preparation of the perovskite layer: S31. PbI2, FAI, MABr, and PbBr2 in a molar ratio of 1.2:1:0.2:0.2 are dissolved in a mixed solvent of DMF and DMSO (volume ratio 4:1) to obtain a perovskite precursor solution with a concentration of 1.4 M. S32. Spin-coat the prepared perovskite precursor solution onto the interface bridging layer at 4500 rpm. Add 200 μL of anhydrous toluene as an antisolvent 10 seconds after the spin-coating begins. Anneal at 100°C for 40 min and allow to cool naturally to obtain a perovskite layer with a thickness of 400 nm.

[0048] S4. Preparation of the hole transport layer: S41. Spiro-OMeTAD is dissolved in anhydrous chlorobenzene and stirred thoroughly until completely dissolved to form a clear solution with a concentration of 72.3 mg / mL. 17.5 μL of acetonitrile solution of lithium bis(trifluoromethane)sulfonylimide (concentration of 520 mg / mL) and 28.8 μL of 4-tert-butylpyridine are added to the clear solution and stirred for 40 min to obtain the hole transport layer material. S42. Spin-coat the hole transport layer material onto the perovskite layer at a rotation speed of 4500 rpm for 35s, and then anneal at 70°C for 12min to obtain a hole transport layer with a thickness of 70nm.

[0049] S5. Preparation of the electrode layer: After P2 scribing in the above components, at 5×10 -6 Under high vacuum, a 100 nm layer of silver is first deposited to obtain the counter electrode layer. Then, after P3 scribing and edge cleaning, the upright perovskite solar cell #3 is obtained.

[0050] Example 4: This example provides a highly stable perovskite solar cell and its fabrication method.

[0051] The perovskite solar cell #4 in this embodiment has an upright structure, consisting of a conductive glass electrode layer, an electron transport layer, an interface bridging layer, a perovskite layer, a hole transport layer, and a counter electrode layer from bottom to top.

[0052] The preparation method includes the following steps: S1. Fabrication of the electron transport layer: S11. Scribing the FTO glass substrate with P1, ultrasonically cleaning it in Hellmanex III detergent aqueous solution, deionized water, acetone and isopropanol for 15 min each, and then drying it with nitrogen. S12. SnO2 solution was spin-coated onto a clean FTO glass substrate using a solution method at a spin-coating speed of 3500 rpm. After spin-coating, the substrate was annealed at 150℃ for 30 min and then naturally cooled to obtain an electron transport layer with a thickness of 40 nm.

[0053] S2. Preparation of the interface bridging layer: S21. Weigh out tetracarboxyporphyrin and zinc acetate in a molar ratio of 1:1.1 and dissolve them in a mixed solvent of DMF and ethanol in a volume ratio of 1:1. Stir at 50°C for 30 min to obtain the interface bridging layer material. S22. Spin-coat the above interface bridging layer material onto the surface of the electron transport layer at 4000 rpm for 30s, anneal at 100℃ for 10min, and allow to cool naturally to obtain an interface bridging layer with a thickness of 5nm.

[0054] S3, Preparation of the perovskite layer: S31. PbI2, FAI, MABr, and PbBr2 in a molar ratio of 1.2:1:0.2:0.2 are dissolved in a mixed solvent of DMF and DMSO (volume ratio 4:1) to obtain a perovskite precursor solution with a concentration of 1.4 M. S32. Spin-coat the prepared perovskite precursor solution onto the interface bridging layer at 4500 rpm. Add 200 μL of anhydrous toluene as an antisolvent 10 seconds after the spin-coating begins. Anneal at 100°C for 40 min and allow to cool naturally to obtain a perovskite layer with a thickness of 400 nm.

[0055] S4. Preparation of the hole transport layer: S41. Dissolve the undoped organic hole material in anhydrous chlorobenzene and stir thoroughly until completely dissolved to form a clear solution with a concentration of 70 mg / mL. Add 4,4'-di-tert-butyl-2,2'-bipyridine to the clear solution. The mass ratio of 4,4'-di-tert-butyl-2,2'-bipyridine to Spiro-OMeTAD is 1:20. Stir for 40 min to obtain the hole transport layer material.

[0056] S42. Spin-coat the hole transport layer material onto the perovskite layer at a rotation speed of 4500 rpm for 35s, and then anneal at 70°C for 12min to obtain a hole transport layer with a thickness of 70nm.

[0057] S5. Preparation of the electrode layer: After P2 scribing in the above components, at 5×10 -6 Under high vacuum, a 20 nm gold layer is first deposited, followed by an 80 nm silver layer to obtain the counter electrode layer. Then, after P3 scribing and edge cleaning, the upright perovskite solar cell #4 is obtained.

[0058] Example 5: This example provides a highly stable perovskite solar cell and its fabrication method.

[0059] The perovskite solar cell #5 in this embodiment has an upright structure, consisting of a conductive glass electrode layer, an electron transport layer, an interface bridging layer, a perovskite layer, a hole transport layer, and a counter electrode layer from bottom to top.

[0060] The preparation method includes the following steps: S1. Fabrication of the electron transport layer: S11. Scribing the FTO glass substrate with P1, ultrasonically cleaning it in Hellmanex III detergent aqueous solution, deionized water, acetone and isopropanol for 15 min each, and then drying it with nitrogen. S12. SnO2 solution was spin-coated onto a clean FTO glass substrate using a solution method at a spin-coating speed of 3500 rpm. After spin-coating, the substrate was annealed at 150℃ for 30 min and then naturally cooled to obtain an electron transport layer with a thickness of 40 nm.

[0061] S2. Preparation of the interface bridging layer: S21. Weigh out tetracarboxyporphyrin and zinc acetate in a molar ratio of 1:1.1 and dissolve them in a mixed solvent of DMF and ethanol in a volume ratio of 1:1. Stir at 50°C for 30 min to obtain the interface bridging layer material. S22. Spin-coat the above interface bridging layer material onto the surface of the electron transport layer at 4000 rpm for 30s, anneal at 100℃ for 10min, and allow to cool naturally to obtain an interface bridging layer with a thickness of 5nm.

[0062] S3, Preparation of the perovskite layer: S31. PbI2, FAI, MABr, and PbBr2 in a molar ratio of 1.2:1:0.2:0.2 are dissolved in a mixed solvent of DMF and DMSO (volume ratio 4:1) to obtain a perovskite precursor solution with a concentration of 1.4 M. S32. Spin-coat the prepared perovskite precursor solution onto the interface bridging layer at 4500 rpm. Add 200 μL of anhydrous toluene as an antisolvent 10 seconds after the spin-coating begins. Anneal at 100°C for 40 min and allow to cool naturally to obtain a perovskite layer with a thickness of 400 nm.

[0063] S4. Preparation of the hole transport layer: S41. Dissolve the undoped organic hole material in anhydrous chlorobenzene and stir thoroughly until completely dissolved to form a clear solution with a concentration of 75 mg / mL. Add 4,4'-di-tert-butyl-2,2'-bipyridine to the clear solution. The mass ratio of 4,4'-di-tert-butyl-2,2'-bipyridine to Spiro-OMeTAD is 1:50. Stir for 40 min to obtain the hole transport layer material.

[0064] S42. Spin-coat the hole transport layer material onto the perovskite layer at a rotation speed of 4500 rpm for 35s, and then anneal at 70°C for 12min to obtain a hole transport layer with a thickness of 70nm.

[0065] S5. Preparation of the electrode layer: After P2 scribing in the above components, at 5×10 -6 Under high vacuum, a 20 nm gold layer is first deposited, followed by an 80 nm silver layer to obtain the counter electrode layer. Then, after P3 scribing and edge cleaning, the upright perovskite solar cell #5 is obtained.

[0066] Example 6: This example provides a highly stable perovskite solar cell and its fabrication method.

[0067] The perovskite solar cell #6 in this embodiment has an upright structure, consisting of a conductive glass electrode layer, an electron transport layer, an interface bridging layer, a perovskite layer, a hole transport layer, and a counter electrode layer from bottom to top.

[0068] The preparation method includes the following steps: S1. Fabrication of the electron transport layer: S11. Scribing the FTO glass substrate with P1, ultrasonically cleaning it in Hellmanex III detergent aqueous solution, deionized water, acetone and isopropanol for 15 min each, and then drying it with nitrogen. S12. SnO2 solution was spin-coated onto a clean FTO glass substrate using a solution method at a spin-coating speed of 3500 rpm. After spin-coating, the substrate was annealed at 150℃ for 30 min and then naturally cooled to obtain an electron transport layer with a thickness of 40 nm.

[0069] S2. Preparation of the interface bridging layer: S21. Weigh out tetracarboxyporphyrin and zinc acetate in a molar ratio of 1:1.1 and dissolve them in a mixed solvent of DMF and ethanol in a volume ratio of 1:1. Stir at 50°C for 30 min to obtain the interface bridging layer material. S22. Spin-coat the above interface bridging layer material onto the surface of the electron transport layer at 4000 rpm for 30s, anneal at 100℃ for 10min, and allow to cool naturally to obtain an interface bridging layer with a thickness of 5nm.

[0070] S3, Preparation of the perovskite layer: S31. PbI2, FAI, MABr, and PbBr2 in a molar ratio of 1.2:1:0.2:0.2 are dissolved in a mixed solvent of DMF and DMSO (volume ratio 4:1) to obtain a perovskite precursor solution with a concentration of 1.4 M. S32. Spin-coat the prepared perovskite precursor solution onto the interface bridging layer at 4500 rpm. Add 200 μL of anhydrous toluene as an antisolvent 10 seconds after the spin-coating begins. Anneal at 100°C for 40 min and allow to cool naturally to obtain a perovskite layer with a thickness of 400 nm.

[0071] S4. Preparation of the hole transport layer: S41. Dissolve the undoped organic hole material in anhydrous chlorobenzene and stir thoroughly until completely dissolved to form a clear solution with a concentration of 72.3 mg / mL. Add 4,4'-di-tert-butyl-2,2'-bipyridine to the clear solution. The mass ratio of 4,4'-di-tert-butyl-2,2'-bipyridine to Spiro-OMeTAD is 1:35. Stir for 40 min to obtain the hole transport layer material.

[0072] S42. Spin-coat the hole transport layer material onto the perovskite layer at a rotation speed of 4500 rpm for 35s, and then anneal at 70°C for 12min to obtain a hole transport layer with a thickness of 70nm.

[0073] S5. Preparation of the electrode layer: After P2 scribing in the above components, at 5×10 -6 Under high vacuum, a 20 nm gold layer is first deposited, followed by an 80 nm silver layer to obtain the counter electrode layer. Then, after P3 scribing and edge cleaning, the upright perovskite solar cell #6 is obtained.

[0074] Comparative Example 1: This comparative example provides a comparative perovskite solar cell and its preparation method, which has the same structure and preparation method as the perovskite solar cell #6 in Example 6, except that the material of the interface bridging layer only includes zinc acetate and does not contain tetracarboxyporphyrin.

[0075] Comparative Example 2: This comparative example provides a comparative perovskite solar cell and its preparation method, which has the same structure and preparation method as the perovskite solar cell #6 in Example 6, except that tetraphenylporphyrin is used instead of tetracarboxyporphyrin as the material of the interface bridging layer.

[0076] Comparative Example 3: This comparative example provides a comparative perovskite solar cell and its preparation method, which has the same structure and preparation method as the perovskite solar cell #6 in Example 6, except that: 2,2'-bipyridine is used instead of 4,4'-di-tert-butyl-2,2'-bipyridine as the hole transport layer material.

[0077] The electrical performance, optical performance, and comprehensive performance indicators of the perovskite solar cells #1-#6 prepared in Examples 1-6 and the comparative perovskite solar cells D1-D3 prepared in Comparative Examples 1-3 were tested. The photoelectric conversion efficiency retention rate after aging at 85°C under a nitrogen atmosphere for 1000 hours was measured. The test results are shown in Table 1.

[0078] Table 1

[0079] As can be seen from the test data obtained in Examples 1-3 in Table 1, especially the test data of Example 1, this application can effectively suppress the energy loss caused by non-radiative recombination by introducing an interface bridging layer, improve interface stability, enhance the electron mobility and conduction band position of SnO2, promote the extraction of interface charge and induce the growth of large-grain perovskite, and improve the overall battery stability.

[0080] Compared to Example 1, Examples 4-6 show improved electrical, optical, and overall performance of perovskite solar cells by adding 4,4'-di-tert-butyl-2,2'-bipyridine to the hole transport layer material without adding any dopant. This is because adding 4,4'-di-tert-butyl-2,2'-bipyridine significantly improves interfacial contact characteristics, suppresses energy loss caused by nonradiative recombination, and enhances the perovskite crystal quality and carrier transport efficiency. By suppressing nonradiative recombination of photogenerated carriers at the interface through interface modification and defect passivation, the number of defects is reduced, thereby improving carrier transport efficiency and ultimately enhancing the efficiency and stability of PSCs.

[0081] Compared to Example 6, Comparative Example 1, which used an interface bridging layer containing only zinc acetate and lacking tetracarboxyporphyrin, showed inferior performance in all aspects compared to Comparative Perovskite Solar Cell D1. This is because the porphyrin units in the tetracarboxyporphyrin are oriented, forming a vertical electron transport channel from SnO2 to the perovskite layer, significantly promoting electron extraction and transport speed. Its four carboxyl groups (-COOH) are used to interact with Zn... 2+ Coordination occurs, and one of the carboxyl groups can form a strong coordination bond with the hydroxyl group (-OH) on the SnO2 surface, enabling in-situ anchoring and growth of the interfacial bridging layer material on SnO2. 2+ Coordination strongly passivates lead defects in the perovskite layer.

[0082] Compared with Example 6, the material of the interface bridging layer in Comparative Example 2 was tetraphenylporphyrin instead of tetracarboxyporphyrin. The performance of the resulting comparative perovskite solar cell D2 was inferior to that of perovskite solar cell #6. This is because although both tetraphenylporphyrin and tetracarboxyporphyrin have porphyrin structures, tetraphenylporphyrin is poorly soluble in water and polar solvents and cannot be liquid-phase epitaxially grown on the hydrophilic SnO2 surface.

[0083] Compared to Example 6, Comparative Example 3 used 2,2'-bipyridine instead of 4,4'-di-tert-butyl-2,2'-bipyridine as the hole transport layer material. The resulting comparative perovskite solar cell D3 exhibited inferior performance across all aspects compared to perovskite solar cell #6. This was because the 4,4'-di-tert-butyl-2,2'-bipyridine molecules were uniformly dispersed in a chlorobenzene solution of the organic hole material. In this case, there was no Li in the solution.+ The dopants compete for coordination with 4,4'-di-tert-butyl-2,2'-bipyridine, and all bipyridine sites in the 4,4'-di-tert-butyl-2,2'-bipyridine molecules can interact with the perovskite surface. Because there is no hygroscopic lithium salt, the solution stability is higher. 4,4'-di-tert-butyl-2,2'-bipyridine, through strong passivation, minimizes interfacial recombination losses, thereby maintaining the high stability of the battery.

[0084] Therefore, it can be seen that materials that are missing or replaced in perovskite solar cells cannot play a role in perovskite solar cells, but will instead reduce the effectiveness of perovskite solar cells. Thus, each component cannot be arbitrarily replaced by other materials.

[0085] The above are all preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A highly stable perovskite solar cell, characterized in that, The perovskite solar cell has an upright structure, consisting of, from bottom to top, a conductive glass electrode layer, an electron transport layer, a perovskite layer, a hole transport layer, and a counter electrode layer. The conductive glass electrode layer is made of an FTO glass substrate or an ITO glass substrate. The counter electrode layer is made of one or more of Al, Ag, Au, Mo, and Cr, with a thickness of 60-120 nm. The electron transport layer is a SnO2 layer with a thickness of 10-120 nm. The perovskite in the perovskite layer is a semiconductor compound with an ABX3 structure, where A is NH=CHNH. 3+ CH3NH 3+ or Cs + B is Pb 2+ or Sn 2+ ;X is I - Cl - or Br - The thickness is 300-700nm; the hole transport layer is made of organic hole material with a thickness of 20-120nm; an interface bridging layer with a thickness of 2-10nm is also provided between the electron transport layer and the perovskite layer.

2. The high-stability perovskite solar cell according to claim 1, characterized in that, The material of the interface bridging layer includes tetracarboxyporphyrin and zinc acetate in a molar ratio of 1:1-1.

2.

3. The highly stable perovskite solar cell according to claim 2, characterized in that, The preparation steps of the interface bridging layer material are as follows: weigh tetracarboxyporphyrin and zinc acetate and dissolve them in a mixed solvent of DMF and ethanol with a volume ratio of 1:

1. Stir at 45-55℃ for 25-35 minutes to obtain the interface bridging layer material.

4. The highly stable perovskite solar cell and its fabrication method according to claim 1, characterized in that, The hole transport layer is composed of a homogeneous composite of 4,4'-di-tert-butyl-2,2'-bipyridine and an undoped organic hole material in a mass ratio of 1:20-50. The organic hole material is any one of Spiro-OMeTAD, poly-TPD, copper phthalocyanine, nickel phthalocyanine, poly(triarylamine), and poly(3-hexylthiophene).

5. The highly stable perovskite solar cell and its preparation method according to claim 4, characterized in that, The preparation steps of the hole transport layer material are as follows: Dissolve the undoped organic hole material in anhydrous chlorobenzene and stir thoroughly until completely dissolved to form a clear solution with a concentration of 70-75 mg / mL. Add 4,4'-di-tert-butyl-2,2'-bipyridine to the clear solution and stir for 30-40 min to obtain a composite solution, which is the hole transport layer material.

6. A method for preparing a highly stable perovskite solar cell as described in any one of claims 1-5, characterized in that, The preparation method includes the following steps: (1) Preparation of electron transport layer: SnO2 solution was spin-coated onto a clean glass substrate using a solution method at a spin speed of 3000-4000 rpm. After spin-coating, the substrate was annealed at 150℃ for 30 min and then naturally cooled to obtain the electron transport layer. (2) Preparation of interface bridging layer: Spin-coating the interface bridging layer material onto the surface of the electron transport layer at 3500-4500 rpm for 25-35s, annealing at 100℃ for 10min, and naturally cooling to obtain the interface bridging layer. (3) Preparation of perovskite layer: The prepared perovskite precursor solution is spin-coated onto the interface bridging layer at 4000-5000 rpm. Anhydrous toluene is added dropwise as an antisolvent 5-10s after the spin-coating begins. The mixture is annealed at 100℃ for 30-45min and then naturally cooled to obtain the perovskite layer. (4) Preparation of hole transport layer: The hole transport layer material is spin-coated on the perovskite layer at a rotation speed of 4000-5000 rpm for 30-40s, and then annealed at 70℃ for 10-15min to obtain the hole transport layer. (5) Preparation of counter electrode layer: Metal is deposited on the hole transport layer under high vacuum to obtain counter electrode layer.

7. The application of a highly stable perovskite solar cell in the photovoltaic power generation industry, transportation industry, electronics industry, and Internet of Things industry, characterized in that, The perovskite solar cell is prepared using the high-stability perovskite solar cell as described in any one of claims 1-5, or the perovskite solar cell prepared by the method described in claim 6.

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