Perovskite battery based on co-doped nickel oxide-based hole transport layer and preparation method thereof

Abstract

The invention relates to a perovskite battery based on a co-doped nickel oxide-based hole transport layer and a preparation method of the perovskite battery. The perovskite battery sequentially comprises a conductive substrate, a hole transport layer, an ionic liquid modification layer, a perovskite active layer, an electron transport layer, a hole barrier layer and a metal electrode layer from bottom to top, and the hole transport layer is a Li-Nb co-doped nickel oxide thin film. According to the invention, by introducing the Li and Nb elements, the hole concentration and mobility can be synergistically improved, the energy level arrangement can be optimized, the morphology and crystallinity of the thin film can be improved, the problems of insufficient conductivity, energy band mismatch, interface recombination and the like of NiO-based HTL can be solved, and finally, the perovskite solar cell with higher efficiency, stability and reliability can be realized. The ionic liquid modification layer is also introduced, so that the interface contact between the thin film and the perovskite material can be improved, the contact side reaction is inhibited, and the service life of the perovskite battery is prolonged.

Description

Technical Field

[0001] This invention belongs to the field of perovskite solar cells, specifically relating to a perovskite solar cell based on a co-doped nickel oxide-based hole transport layer and its preparation method. Background Technology

[0002] Perovskite solar cells (PSCs), as a third-generation photovoltaic technology, have attracted much attention due to their low material cost, simple fabrication process, and rapid improvement in photoelectric conversion efficiency (PCE) (laboratory certified efficiency has exceeded 27%). In the device structure of PSCs, the hole transport layer (HTL) plays a crucial role in the cell's efficiency and stability. Among them, inorganic p-type semiconductor nickel oxide (NiO) x Due to its excellent chemical stability, high hole mobility, suitable valence band position (~5.4 eV), and good energy level matching with the perovskite layer, it has become one of the most promising HTL materials for industrialization among inverted PSCs.

[0003] However, traditional NiO x There are still a series of key problems to be solved in the preparation and application of HTLs, such as:

[0004] (1) Insufficient intrinsic electrical properties: Pure NiO x Thin films often exhibit low intrinsic conductivity (typically below 10). -4 The low hole mobility (S / cm) and low hole extraction and transport capabilities lead to the accumulation and recombination of interfacial charges, resulting in low fill factor (FF) and short-circuit current density (Jsc) of the battery.

[0005] (2) Interface energy level mismatch and defects: NiO x The surface often contains a large number of high-valence nickel ions (such as Ni). 3+ These defect states not only act as charge recombination centers, reducing the open-circuit voltage (Voc), but also catalyze the decomposition of the perovskite layer, accelerating device degradation, especially under ultraviolet light. Furthermore, NiO... x There may be a potential barrier between the HOMO energy level and commonly used transparent conductive oxide electrodes (such as ITO) and the valence band of the perovskite layer, which hinders the efficient extraction of holes.

[0006] (3) Challenges in preparation process and morphology control: Limitations of solution methods: Although solution methods (such as nanoparticle coating) can be prepared at low temperatures, it is difficult to achieve large-area, high-coverage, and pinhole-free dense films, which can easily lead to leakage of perovskite precursor solutions or poor interfacial contact, resulting in leakage current and efficiency loss. Poor interfacial compatibility of vacuum methods: Vacuum deposition (such as sputtering, evaporation) of NiO xThin film surfaces are often hydrophobic and rich in defects, resulting in poor wettability and chemical compatibility with solution-processed perovskite layers, affecting the uniformity of perovskite film formation and interfacial bonding strength. High-temperature dependence: High-performance NiO x Thin films (especially sputtered films) typically require high-temperature annealing (>300°C) to improve crystallinity and conductivity, which directly conflicts with the low-temperature processing (≤120°C) requirements of flexible substrates (such as PET and PEN), limiting their application in flexible devices.

[0007] (4) Bottlenecks in large-area fabrication and stability: The laboratory small-area high-performance battery (<0.1 cm²) 2 The results have been extended to practical components (>10 cm) 2 When NiO x The uniformity of the NiO layer, its conductivity, and the uniformity of the interface passivation effect face severe challenges. x The long-term stability of the perovskite interface (especially under humid heat and light) remains a core obstacle to industrialization.

[0008] These issues have all become current problems for NiO x Improvements to the focusing capabilities of the nickel oxide-based hole transport layer are needed. To address this, we provide a method for fabricating a nickel oxide-based hole transport layer and a perovskite solar cell to solve the aforementioned problems. Summary of the Invention

[0009] The purpose of this invention is to address the problems existing in the prior art by providing a perovskite solar cell based on a co-doped nickel oxide-based hole transport layer and its preparation method.

[0010] This invention prepares a nickel oxide thin film by doping with one or more elements, and then modifies the surface of the film using an ionic liquid, thereby modifying the hole transport interface. This can synergistically improve hole concentration and mobility, optimize energy level arrangement, and improve film morphology and crystallinity, while solving problems such as insufficient conductivity, band mismatch, and interface recombination in NiO-based HTLs, ultimately achieving a more efficient, stable, and reliable perovskite solar cell.

[0011] The objective of this invention can be achieved through the following methods: This invention provides a perovskite solar cell based on a co-doped nickel oxide-based hole transport layer, comprising, from bottom to top: Conductive substrate, hole transport layer, ionic liquid modification layer, perovskite active layer, electron transport layer, hole blocking layer, metal electrode layer; The hole transport layer is a Li-Nb co-doped nickel oxide thin film.

[0012] This invention employs Li-Nb co-doping, which has the following advantages: (1) Synergistic optimization of electrical and structural properties: Li doping can effectively regulate NiO x The Fermi level is increased, increasing the hole carrier concentration, thereby reducing the film resistance and improving hole extraction and transport efficiency. Simultaneously, high-valence Nb is introduced. 5+ (ionic radius and Ni) 2+ (Similar to) can enter the crystal lattice. The strong Nb-O bond can act as an "anchor" to stabilize the layered crystal structure, suppressing phase transitions and structural collapse caused by ion migration during cycling or operation. The division of labor between "Li as the main external component (electrical) and Nb as the main internal component (structural)" is the key to achieving both high performance and high stability.

[0013] (2) Synergistic suppression of defects and side reactions: NiO x Oxygen vacancies in Nb are the primary charge recombination centers and can severely impair device performance. 5+ The introduction of Li significantly increases the formation energy of oxygen vacancies, fundamentally suppressing their generation. Simultaneously, the stable lattice structure reduces the loss of reactive oxygen species during high potentials or long-term operation. The well-conducting interface formed by Li doping helps to homogenize the electric field distribution and reduce local current overload. Together, these factors greatly enhance the stability of the thin film and device interface, delaying performance degradation.

[0014] As one embodiment of the present invention, the preparation method of the Li-Nb co-doped nickel oxide thin film is one of magnetron sputtering, sol-gel method, electrochemical deposition method, and atomic layer deposition method.

[0015] The preferred preparation method is magnetron sputtering, which is environmentally friendly with no waste, has high deposition efficiency, wide material coverage, can be deposited at low temperatures, and produces thin films with good adhesion to the substrate. It can also sputter different materials simultaneously, and has unique advantages, especially in large-area preparation and industrialization.

[0016] Furthermore, the Li-Nb co-doped nickel oxide thin film is prepared by magnetron sputtering, including the following steps: The conductive substrate is transferred to the magnetron sputtering chamber. After the chamber is evacuated to a base vacuum, it is filled with an argon-oxygen mixture. After adjusting to a certain working pressure, the power is turned on to sputter the nickel oxide ceramic target (Li content 0-1%, Nb content 0-1%). After sputtering, the target is annealed to obtain a Li-Nb co-doped nickel oxide film.

[0017] Furthermore, the cavity's background vacuum is 7-9 × 10⁻⁶. -4 Pa, preferably 7.5-8.5×10 -4 Pa.

[0018] Furthermore, the magnetron sputtering process is carried out in a mixed atmosphere of argon and oxygen, with an oxygen / (argon + oxygen) flux ratio of 10-20%, preferably 14-16%.

[0019] Furthermore, the working pressure is 1-3 Pa, preferably 2-3 Pa.

[0020] Furthermore, the target material used for magnetron sputtering is a nickel oxide ceramic target with a content of 0-1% Li and 0-1% Nb; the power range of magnetron sputtering is 100-200 W; preferably 150-200 W. The Li content in the nickel oxide ceramic target is preferably 0.5-0.7%, and the Nb content is preferably 0.5-0.7%.

[0021] Furthermore, the substrate holder swings at a speed of 20-30 mm / s and swings 20-40 times.

[0022] Furthermore, the annealing temperature is 250-350℃, preferably 280-320℃, and the time is 50-70 min.

[0023] Furthermore, the thickness of the Li-Nb co-doped nickel oxide film is 50-60 nm.

[0024] As one embodiment of the present invention, the ionic liquid modified layer is prepared by: coating an ionic liquid solution onto the surface of a Li-Nb co-doped nickel oxide film to form an ionic liquid modified layer.

[0025] Furthermore, the solvent used in the ionic liquid precursor solution is any one or more of ethanol, acetonitrile, ethyl acetate, and isopropanol.

[0026] Furthermore, the concentration of the ionic liquid precursor solution is 0.5-2.0 mg / ml, preferably 0.5-1.5 mg / ml.

[0027] Furthermore, the ionic liquid comprises at least one of 3-methyl-1-vinyl-1H-imidazolium-3-onium tetrafluoroborate, 1-benzyl-3-methylimidazolium hexafluorophosphate, and 1,3-dimethylimidazolium dimethyl phosphate.

[0028] The structural formula of the above ionic liquid molecule is: , , .

[0029] Furthermore, the thickness of the ionic liquid modification layer is 5-10 nm.

[0030] As one embodiment of the present invention, the transparent conductive substrate is selected from ITO, FTO, and IZO conductive glass.

[0031] As one embodiment of the present invention, the electron transport layer adopts C 60 .

[0032] In one embodiment of the present invention, the electron blocking layer is a BCP.

[0033] As one embodiment of the present invention, the metal electrode is one of gold, silver, and copper; As one embodiment of the present invention, the perovskite active layer includes methylamine hydrohalate, cesium halide, formamidinyl hydrohalate, methyl ammonium halide and lead halide.

[0034] Preferably, the methylamine hydrohalate is selected from at least one of methylamine hydrochloride and methylamine iodide.

[0035] Preferably, the cesium halide is selected from at least one of cesium iodide, cesium bromide, and cesium chloride.

[0036] Preferably, the formamidine hydrohalate is selected from at least one of formamidine hydroiodate and formamidine hydrochloride.

[0037] Preferably, the methyl ammonium halide salt is selected from at least one of methyl ammonium iodide, methyl ammonium bromide, and methyl ammonium chloride.

[0038] Preferably, the lead halide is selected from at least one of lead iodide, lead bromide, and lead chloride.

[0039] Preferably, the thickness of the perovskite active layer is 450-550 nm.

[0040] Preferably, the thickness of the electron transport layer is 30-40 nm.

[0041] Preferably, the thickness of the hole blocking layer is 5-10 nm.

[0042] Preferably, the thickness of the metal electrode layer is 80-120 nm.

[0043] This invention also provides a method for fabricating a perovskite solar cell based on a co-doped nickel oxide hole transport layer, comprising the following steps: The conductive substrate is cleaned, and a Li-Nb co-doped nickel oxide film is deposited on the conductive substrate. Then, an ionic liquid solution is coated to form an ionic liquid modification layer. Then, a perovskite active layer, an electron transport layer, a hole blocking layer, and a metal electrode layer are prepared in sequence to obtain a perovskite solar cell based on a co-doped nickel oxide hole transport layer.

[0044] This invention employs Li-Nb co-doping, which works in conjunction with ionic liquids: (1) "Internal reinforcement" of Li-Nb co-doping: Li + and Nb5+ The doping of these materials improved the conductivity and crystal structure stability of the nickel oxide film, providing a high-performance foundation from the bulk material level.

[0045] (2) Ionic liquids as “interfacial bridges”: Ionic liquids form an ultrathin modification layer on the surface of Li-Nb co-doped nickel oxide films. The cation portion binds to the perovskite, while the anion portion binds to the nickel oxide surface, acting as a “molecular bridge.” This not only improves physical contact but also passivates active defects through electrostatic interactions that saturate interfacial dangling bonds.

[0046] (3) Synergistic effect: The combination of stable bulk material (Li-Nb co-doped nickel oxide) and highly optimized interface (ionic liquid modification layer) solves the two key bottlenecks of low charge transport efficiency and poor interface stability at the same time, thereby achieving simultaneous improvement in efficiency and stability.

[0047] Compared with the prior art, the present invention has the following beneficial effects: (1) This invention introduces new energy levels or orbital hybridization through element doping, thereby changing the valence band structure and enabling the control of the band structure of nickel oxide thin films to meet the energy level matching requirements of different perovskite solar cell materials. Furthermore, Li-Nb co-doping can synergistically improve the hole concentration and mobility of nickel oxide thin films, optimize energy level arrangement, and improve film morphology and crystallinity. At the same time, it solves the problems of insufficient conductivity, band mismatch, and interface recombination in NiO-based HTL, ultimately achieving higher efficiency, more stable, and more reliable perovskite solar cells.

[0048] (2) The present invention provides a method for surface modification of nickel oxide-based thin films, which improves the interfacial contact between the thin film and the perovskite material, suppresses contact side reactions, and prolongs the life of perovskite cells by coating an ionic liquid solution modification layer on the surface of the doped nickel oxide thin film. Attached Figure Description

[0049] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 A schematic diagram of a perovskite solar cell module with a nickel oxide-based hole transport layer; Figure 2 The graph shows the performance test results of Example 2 and Comparative Example 1; Figure 3 The graph shows the stability test results for Examples 1 and 2. Detailed Implementation

[0050] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The following examples are implemented under the premise of the technical solution of the present invention, providing detailed implementation methods and specific operating procedures, which will help those skilled in the art to further understand the present invention. It should be noted that the scope of protection of the present invention is not limited to the following embodiments; any adjustments and improvements made under the concept of the present invention are all within the scope of protection of the present invention.

[0051] This invention provides a perovskite solar cell based on a co-doped nickel oxide hole transport layer, such as... Figure 1 As shown, from bottom to top, it includes: a conductive substrate, a hole transport layer, an ionic liquid modification layer, a perovskite active layer, an electron transport layer, a hole blocking layer, and a metal electrode layer. The hole transport layer is a Li-Nb co-doped nickel oxide thin film.

[0052] The ionic liquid used in the ionic liquid modification layer is at least one of 3-methyl-1-vinyl-1H-imidazolium-3-onium tetrafluoroborate, 1-benzyl-3-methylimidazolium hexafluorophosphate, and 1,3-dimethylimidazolium dimethyl phosphate.

[0053] 3-Methyl-1-vinyl-1H-imidazolium-3-onium tetrafluoroborate contains a vinyl group, which is a reactive functional group. This means that under specific conditions (such as heating, light exposure, or the addition of an initiator), these molecules can form a cross-linked, stable polymer network at the interface through the polymerization of vinyl groups. Based on its polymerizability, it has applications in modifying Li-Nb co-doped NiO. x When a hole transport layer is formed, it can bring unique advantages that surpass those of conventional ionic liquids: (1) Formation of a stable covalent interface layer. Before or during the deposition of the perovskite layer, polymerization is initiated by heat or light, causing cross-linking between ionic liquid molecules to form a strong, insoluble polymer film. This greatly enhances the mechanical and chemical stability of the interface layer.

[0054] (2) Achieve better defect passivation and encapsulation. The network formed by polymerization can more firmly "lock in" anions (BF4). - This allows for more effective passivation of NiO. x Surface defects. At the same time, the dense polymer layer can more effectively block the intrusion of moisture and oxygen, as well as the bidirectional migration of metal ions.

[0055] (3) Precisely control the interfacial properties. By controlling the degree of polymerization (such as light exposure time and temperature), the thickness of the interfacial layer, its hydrophilicity and hydrophobicity, and its interaction with the perovskite precursor can be precisely controlled, thereby optimizing the crystallization of perovskite.

[0056] (4) For Li-Nb co-doped NiOx The system, using this polymerizable ionic liquid, promises to achieve "triple stability": ① Bulk stability: Li-Nb co-doping optimizes NiO x Internal electrical and structural stability.

[0057] ② Interfacial chemical stability: imidazolium cation and BF4 - Anions provide excellent passivation of interfacial defects and energy level tuning.

[0058] ③ Physically stable interface: The cross-linked network formed by polymerization provides strong physical protection and diffusion barrier capabilities.

[0059] This combination can synergistically solve several key problems at the interface, such as charge recombination, chemical degradation, and ion migration, and has great potential in improving the long-term operational stability and resistance to damp heat of devices.

[0060] The benzyl group of the benzyl group in 1-benzyl-3-methylimidazolium hexafluorophosphate can react with NiO through π-π stacking or cation-π interaction. x Organic components on the surface or in the perovskite generate stronger non-covalent interactions, anchoring molecules more firmly and orderly at the interface. Rigid benzene rings can promote the alignment of imidazole cations at the interface in specific orientations more favorable for hole transport. PF6 - It exhibits excellent chemical and electrochemical stability and strong hydrophobicity, effectively resisting environmental moisture erosion and protecting the interface. It can be used to modify your Li-Nb co-doped NiO. x It can synergistically improve device performance: (1) Strong defect passivation PF6 - The F atoms in the NiO can effectively passivate NiO. x Ni on the surface 3+ Defects and uncoordinated Pb in the perovskite substrate 2+ The strong adsorption of benzyl groups makes this passivation layer more stable.

[0061] (2) The strong electron-withdrawing effect (inductive effect) of the benzyl group can further reduce the NiO content. x The surface work function allows for better matching with the valence band of perovskite, thus improving hole extraction efficiency.

[0062] (3) Enhanced hydrophobicity and barrier effect PF6 - Together with the ordered benzyl groups, they form a hydrophobic layer that blocks water and oxygen intrusion and inhibits ion migration at the interface, significantly improving the environmental stability of the device.

[0063] (4) A more uniform and stable monolayer can provide ideal nucleation sites for perovskite, which helps to form high-quality perovskite films.

[0064] In 1,3-dimethylimidazolium dimethyl phosphate, the cation is 1,3-dimethylimidazolium: its simple, symmetrical structure, small size, and lack of long alkyl chains provide the basic ionic liquid framework and electrostatic interactions. Its small size facilitates the formation of a dense monolayer. The anionic dimethyl phosphate has the structure (CH3O)2PO2. - It is the core functional group. Its P=O and PO- groups are excellent electron donors for metal ions (such as Ni). 2+ / Ni 3+ Pb 2+ It possesses strong coordination ability, enabling "targeted" chemical passivation. In the modification of NiO... x At the perovskite interface, advantages may be derived through the following mechanisms: (1) The oxygen atom on the P=O double bond of the dimethyl phosphate anion can strongly coordinate and passivate NiO. x uncoordinated Ni on the surface 3+ (Main complex center), and can also passivate Pb at the bottom of perovskite. 2+ Defects. This passivation may be more pronounced than BF4. - More direct and more robust.

[0065] (2) The cations are small in size and the anions have a clear coordination direction. The combination of the two may be beneficial to the molecular structure in NiO. x The surface is densely and orderly arranged, forming a high-quality decorative layer.

[0066] (3) Strong coordination may change the interfacial charge distribution, thereby fine-tuning NiO x The surface work function promotes energy level alignment.

[0067] (4) Dimethyl phosphate is more hydrophobic than BF4. - However, it is weaker than PF6. - It can achieve a good balance between passivation and moisture protection.

[0068] Example 1 This embodiment provides an inverted perovskite solar cell and its fabrication method, comprising, from bottom to top: a transparent substrate 1, the aforementioned hole transport layer 2, an ionic liquid modification layer 3, a perovskite active layer 4, an electron transport layer 5, a hole blocking layer 6, and a metal electrode 7.

[0069] This embodiment provides a method for fabricating a perovskite solar cell module with a co-doped nickel oxide-based hole transport layer, including the following steps: (1) Cleaning and treatment of transparent conductive substrate: The substrate was ultrasonically cleaned for 30 min in sequence with glass cleaner, deionized water, acetone and isopropanol, dried with nitrogen gun and then treated with ultraviolet ozone for 20 min.

[0070] (2) Laser scribing of P1 lines was performed on the substrate after the above treatment using a wavelength of 550 nm. A total of 42 P1 lines were formed, with each line spaced 6.5 mm apart.

[0071] (3) Preparation of hole transport layer: The above-mentioned FTO transparent substrate is transferred to the magnetron sputtering chamber, and the chamber background vacuum is evacuated to 8×10⁻⁶. -4 When the pressure is below Pa, gas is introduced into the cavity, with an oxygen / (argon + oxygen) flux ratio of 15% and a working pressure of 2.4 Pa. The sputtering target is a nickel oxide ceramic target with 0.6% Li and 0.6% Nb content, and the magnetron sputtering power is 180 W. Two power supplies are simultaneously turned on for co-sputtering. The substrate holder oscillation speed is 25 mm / s, and the substrate is passed 30 times. After sputtering, the film is heat-treated at 300 °C for 60 min, finally obtaining a Li-Nb co-doped nickel oxide film with a thickness of 55 nm.

[0072] (4) Ionic liquid modified hole transport layer: At room temperature, a 3-methyl-1-vinyl-1H-imidazolium-3-onium tetrafluoroborate solution with a concentration of 1 mg / ml was coated on the surface of the above nickel oxide film to obtain an interface-modified hole transport layer with a thickness of 8 nm.

[0073] (5) Preparation of perovskite active layer: Prepare 1.0 M Cs 0.05 FA 0.95 A perovskite precursor solution was obtained by stirring a PbI3 solution with a mixed solvent of DMF and NMP (DMF:NMP volume ratio of 9:1) at room temperature for 4 hours. A perovskite layer was then slit-coated onto the modified layer using the following parameters: a 220 μm slit between the doctor blade and the substrate, and a coating speed of 15 mm / s. After flash evaporation of the coated perovskite layer, it was annealed on a hot plate at 120 °C for 10 min, yielding a 500 nm thick perovskite active layer.

[0074] (6) Electron transport layer and electron blocking layer: 35 nm C60 is vacuum-deposited on top of the perovskite active layer as an electron transport layer and 5 nm BCP is deposited as a hole blocking layer.

[0075] (7) On this basis, P2 laser etching is performed. The laser uses a wavelength of 550 nm and has 41 lines. The distance from P2 to P1 is about 35 μm.

[0076] (8) Preparation of metal electrode layer: Vacuum evaporation of about 100 nm Ag as metal electrode layer.

[0077] (9) The deposited Ag electrode is etched with P3 using a laser with a wavelength of 550 nm. There are 42 lines in total, and the distance from P3 to P2 is about 32 μm.

[0078] (10) Finally, clean the edge with P4, 10 mm away.

[0079] This results in a perovskite solar cell module based on a nickel oxide-based hole transport layer.

[0080] Example 2 This embodiment provides an inverted perovskite solar cell and its preparation method, which is basically the same as that in Example 1, except that: (4) the ionic liquid 3-methyl-1-vinyl-1H-imidazolium-3-onium tetrafluoroborate is replaced with 1-benzyl-3-methylimidazolium hexafluorophosphate, and the solution concentration remains unchanged.

[0081] Example 3 This embodiment provides an inverted perovskite solar cell and its preparation method, which is basically the same as that in Example 1, except that: (4) the ionic liquid 3-methyl-1-vinyl-1H-imidazolium-3-onium tetrafluoroborate is replaced with 1,3-dimethylimidazolium dimethyl phosphate, and the solution concentration remains unchanged.

[0082] Comparative Example 1 This comparative example provides a method for preparing a perovskite solar cell module with a nickel oxide-based hole transport layer, which is basically the same as that in Example 1, except that: (3) only Ni target sputtering is used in the hole transport layer preparation process, and the other conditions remain unchanged.

[0083] Comparative Example 2 (Li-doped only) This comparative example provides a method for preparing a perovskite solar cell module with a nickel oxide-based hole transport layer, which is basically the same as that in Example 1, except that: (3) when preparing the hole transport layer, a nickel oxide ceramic target with a content of 1.2% Li is used to ensure that the total doping amount remains unchanged.

[0084] Comparative Example 3 (Nb-doped only) This comparative example provides a method for preparing a perovskite solar cell module with a nickel oxide-based hole transport layer, which is basically the same as that in Example 1, except that: (3) when preparing the hole transport layer, a nickel oxide ceramic target with a content of 1.2% Nb is used to ensure that the total doping amount remains unchanged.

[0085] Comparative Example 4 (doped with other elements) This comparative example provides a method for preparing a perovskite solar cell module with a nickel oxide-based hole transport layer, which is basically the same as that in Example 1, except that: (3) when preparing the hole transport layer, a nickel oxide ceramic target with a content of 0.6% Mg and 0.6% Nb is used to ensure that the total doping amount remains unchanged.

[0086] Comparative Example 5 (Ionic Liquid Replacement) This comparative example provides a method for preparing a perovskite solar cell module with a nickel oxide-based hole transport layer, which is basically the same as that in Example 1, except that the ionic liquid is replaced with 1-butyl-3-methylimidazolium tetrafluoroborate.

[0087] Comparative Example 6 (Ionic Liquid Replacement) This comparative example provides a method for preparing a perovskite solar cell module with a nickel oxide-based hole transport layer, which is basically the same as that in Example 1, except that the ionic liquid is replaced with 1-butyl-3-methylimidazolium dinitrile ammonium salt.

[0088] Comparative Example 7 (different preparation methods) This comparative example provides a method for preparing a perovskite solar cell module with a nickel oxide-based hole transport layer, which is basically the same as that in Example 1, except that: an ionic liquid is added to the perovskite precursor solution, and the modification layer is not prepared separately.

[0089] The photoelectric conversion efficiency of the fabricated perovskite photovoltaic modules was tested under simulated standard solar conditions using a steady-state solar cell module simulator (Shaanxi Zhongsen GSIV-22A0606). The photoelectric performance tests of the perovskite solar cells in the examples and comparative examples are shown in Table 1. Figure 2 and Figure 3 As shown.

[0090] Table 1

[0091] The photoelectric conversion efficiency of the embodiments was significantly better than that of the comparative examples, and the efficiencies of Embodiments 1 and 2 were higher (Embodiment 2 was slightly better than Embodiment 1, and both were significantly better than Embodiment 3). The unencapsulated components were stored under environmental conditions (room temperature, relative humidity 20%-40%), and their photoelectric efficiency was tested every 100 hours to continuously monitor their stability. After 700 hours, the component stability showed significant differences, with Embodiment 1 being superior to Embodiment 2.

[0092] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A perovskite solar cell based on a co-doped nickel oxide-based hole transport layer, characterized in that, From bottom to top, they include: Conductive substrate, hole transport layer, ionic liquid modification layer, perovskite active layer, electron transport layer, hole blocking layer, metal electrode layer; The hole transport layer is a Li-Nb co-doped nickel oxide thin film; The ionic liquid in the ionic liquid modified layer includes at least one of 3-methyl-1-vinyl-1H-imidazolium-3-onium tetrafluoroborate, 1-benzyl-3-methylimidazolium hexafluorophosphate, and 1,3-dimethylimidazolium dimethyl phosphate.

2. The perovskite solar cell based on a co-doped nickel oxide hole transport layer according to claim 1, characterized in that, The Li-Nb co-doped nickel oxide thin film is prepared by one of the following methods: magnetron sputtering, sol-gel method, electrochemical deposition method, and atomic layer deposition method.

3. The perovskite solar cell based on a co-doped nickel oxide hole transport layer according to claim 2, characterized in that, The Li-Nb co-doped nickel oxide thin film was prepared by magnetron sputtering, including the following steps: The conductive substrate is transferred to the magnetron sputtering chamber. After the chamber is evacuated to a base vacuum, it is filled with an argon-oxygen mixture. After adjusting to a certain working pressure, the power is turned on to sputter the nickel oxide ceramic target (Li content 0-1%, Nb content 0-1%). After sputtering, the target is annealed to obtain a Li-Nb co-doped nickel oxide film.

4. The perovskite solar cell based on a co-doped nickel oxide hole transport layer according to claim 3, characterized in that, The cavity's base vacuum is 7-9 × 10⁻⁶. -4 Pa; And / or, the magnetron sputtering process is carried out in a mixed atmosphere of argon and oxygen, with an oxygen / (argon + oxygen) flux ratio of 10-20%; And / or, the working pressure is 1-3 Pa; And / or, the target material used for magnetron sputtering is a nickel oxide ceramic target material with a content of 0-1% Li and 0-1% Nb; the power range of magnetron sputtering is 100-200 W; And / or, the substrate holder swing speed is 20-30 mm / s, and the number of swings is 20-40; And / or, the annealing temperature is 250-350℃, and the time is 50-70 min.

5. The perovskite solar cell based on a co-doped nickel oxide hole transport layer according to claim 1, characterized in that, The method for preparing the ionic liquid modified layer is as follows: an ionic liquid solution is coated onto the surface of a Li-Nb co-doped nickel oxide film to form an ionic liquid modified layer.

6. The perovskite solar cell based on a co-doped nickel oxide hole transport layer according to claim 5, characterized in that, The solvent used in the ionic liquid precursor solution is any one or more of ethanol, acetonitrile, ethyl acetate, and isopropanol; And / or, the concentration of the ionic liquid modified solution is 0.5-2.0 mg / ml.

7. The perovskite solar cell based on a co-doped nickel oxide hole transport layer according to claim 1, characterized in that, The thickness of the Li-Nb co-doped nickel oxide film is 50-60 nm; And / or, the thickness of the ionic liquid modification layer is 5-10 nm; And / or, the thickness of the perovskite active layer is 450-550 nm; And / or, the thickness of the electron transport layer is 30-40 nm; And / or, the hole blocking layer has a thickness of 5-10 nm; And / or, the thickness of the metal electrode layer is 80-120 nm.

8. The perovskite solar cell based on a co-doped nickel oxide hole transport layer according to claim 1, characterized in that, The transparent conductive substrate is selected from one of ITO, FTO, and IZO conductive glass; And / or, the electron transport layer adopts C 60 ; And / or, the hole blocking layer employs a BCP; And / or, the metal electrode is one of gold, silver, and copper.

9. The perovskite solar cell based on a co-doped nickel oxide hole transport layer according to claim 1, characterized in that, The materials of the perovskite active layer include methylamine hydrohalate, cesium halide, formamidinyl hydrohalate, methyl ammonium halide, and lead halide.

10. A method for preparing a perovskite solar cell as described in claim 1, characterized in that, Includes the following steps: The conductive substrate is cleaned, and a Li-Nb co-doped nickel oxide film is deposited on the conductive substrate. Then, an ionic liquid solution is coated to form an ionic liquid modification layer. Then, a perovskite active layer, an electron transport layer, a hole blocking layer, and a metal electrode layer are prepared in sequence to obtain a perovskite solar cell based on a co-doped nickel oxide hole transport layer.

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