Perovskite solar cell and preparation method thereof

Abstract

The invention belongs to the technical field of photovoltaic power generation, and provides a perovskite solar cell and a preparation method thereof. The cell comprises a substrate layer, a hole transport layer, a perovskite light absorption layer, a modification layer, an electron transport layer, an interface regulation and control layer and an electrode layer which are sequentially arranged from bottom to top, and the material of the modification layer is chlorophenyl piperazine salt. The preparation method mainly comprises the following steps: spin-coating a chlorphenyl piperazine salt solution on the perovskite light absorption layer, and annealing to obtain the modification layer. According to the chlorphenyl piperazine salt disclosed by the invention, the grain size of the perovskite thin film can be increased, the grain boundary is reduced, and the uniformity and compactness of the perovskite thin film are improved; and meanwhile, ion migration can be inhibited, interface and bulk phase defects can be reduced, interface energy level arrangement of the perovskite light absorption layer / electron transport layer can be optimized, defect auxiliary recombination and non-radiative recombination loss can be reduced, the service life of a film carrier can be prolonged, and the efficiency of a perovskite solar cell device can be further improved.

Description

Technical Field

[0001] This disclosure relates to the field of photovoltaic power generation technology, and in particular to a perovskite solar cell and its preparation method. Background Technology

[0002] Organic-inorganic halide perovskites have attracted widespread attention due to their excellent photoelectric properties, such as high carrier mobility, tunable bandgap, and low cost. After more than a decade of research, the photoelectric conversion efficiency (PCE) of perovskite solar cells (PSCs) has rapidly improved, demonstrating enormous commercial application potential.

[0003] Due to the relatively weak chemical interactions in organic-inorganic hybrid metal halide perovskites, high concentrations of defects form in perovskite films during rapid crystallization and high-temperature annealing. These defects cause nonradiative and interfacial recombination, which severely limits the improvement of the device's PCE (Potentially Optimal Performance). More importantly, the presence of defects provides pathways for ion migration, which accelerates under external stimuli, significantly impacting the long-term stability of PSCs (Potentially Optimal Performance Controllers).

[0004] Grain boundaries are an unavoidable structural feature in polycrystalline perovskite thin films, and numerous studies have confirmed that they are another key factor affecting the performance and stability of perovskite solar cells. Environmental factors such as moisture and oxygen can more easily penetrate from grain boundaries into the interior of the perovskite film, initiating hydrolysis and oxidation of the perovskite material, leading to material decomposition and failure. Therefore, passivating interfaces and bulk defects is of great significance for improving the photoelectric conversion efficiency and long-term operational stability of PSCs.

[0005] Currently, interface engineering is considered an effective method for passivating thin film surface defects and improving device efficiency and stability. Studies have found that passivating agents such as low-dimensional perovskites, Lewis acids, Lewis bases, and organic / inorganic salts are widely used to passivate various defects. However, interface engineering has limitations in passivating perovskite bulk defects. Therefore, developing a method for synergistic passivation of interface and bulk defects is crucial for high-efficiency perovskite solar cells. Summary of the Invention

[0006] This disclosure provides a perovskite solar cell and a method for its fabrication, thereby at least solving the above-mentioned technical problems existing in the prior art.

[0007] According to a first aspect of this disclosure, a perovskite solar cell is provided, comprising, from bottom to top, a substrate layer, a hole transport layer, a perovskite light-absorbing layer (PVK), a modification layer, an electron transport layer (ETL), an interface modulation layer, and an electrode layer; wherein the material of the modification layer is chlorophenylpiperazine salt.

[0008] In one embodiment, the chemical formula of the perovskite structure in the perovskite light-absorbing layer is ABX3, wherein A is selected from at least one of methylammonium cation, formamidinium cation, and cesium ion; B is selected from at least one of lead ion and tin ion; and X is selected from at least one of chloride ion, bromide ion, iodide ion, and thiocyanate ion.

[0009] Specifically, ABX3-type perovskite crystals have high defect tolerance. Using a precursor solution containing ABX3-type perovskite crystals to prepare a perovskite light-absorbing layer helps improve the stability of perovskite solar cell devices. Furthermore, by adjusting the components of ABX3, the band gap of the perovskite material can be changed, thereby increasing the flexibility of perovskite solar cell device applications.

[0010] Specifically, the above-mentioned modified layer has the core role of synergistic surface passivation and bulk enhancement, as follows: (1) Passivating defects and suppressing non-radiative recombination. Chlorophenyl can effectively passivate the site vacancies of X-position anions and the undercoordinated B-position cations in the perovskite light-absorbing layer, reducing the defect sites in the film; the piperazine group can form hydrogen bonds with the A-position cation, and the π-cation interaction induced by the benzene ring can further fix the A-position cation, suppress the migration of the A-position cation, thereby reducing the non-radiative recombination loss caused by ion migration and defects, and improving the utilization efficiency of charge carriers. (2) Inducing secondary grain growth and optimizing film morphology. Chlorophenyl piperazine salt can induce perovskite surface reconstruction, promote secondary grain growth, increase the size of film grains and reduce grain boundaries; it can also regulate the crystallization orientation of perovskite grains, promote more grains to present vertical orientation, improve the uniformity and compactness of the film, and reduce the probability of charge recombination at grain boundaries. (3) Optimizing interface energy levels and improving charge carrier transport performance. The modified layer can optimize the interfacial energy level arrangement between the perovskite light-absorbing layer and the electron transport layer, and reduce carrier recombination caused by interfacial defects; its own strong dipole moment and passivated functional groups can regulate the surface energy level of the device, improve the separation and transport efficiency of carriers, and thus improve the open circuit voltage (VOC), short circuit current (JSC) and fill factor (FF) of the battery. (4) Reduce the residual stress of the film and enhance the stability of the device. After treatment with chlorophenylpiperazine salt, the residual stress of the perovskite film is significantly reduced, which can alleviate the problem of cracks caused by stress in the film; at the same time, it can inhibit the penetration of environmental factors such as moisture and oxygen from the grain boundary, delay the hydrolysis and oxidation of the perovskite material, and improve the long-term operating stability of the device.

[0011] In a preferred embodiment, the chemical formula of the perovskite structure in the perovskite light-absorbing layer is FA. 1-x- y MA x Cs y Pb(I 1-z Br z)3, where x=0~1, y=0~1, z=0~1.

[0012] In one embodiment, the chlorophenylpiperazine salt is selected from at least one of 1-(4-chlorophenyl)piperazine hydrochloride (1-(4-Chlorophenyl)piperazine dihydrochloride, 4CPPDCl), 1-(2-chlorophenyl)piperazine hydrochloride, 1-(3-chlorophenyl)piperazine hydrobromide, 1-(4-chlorophenyl)piperazine nitrate, 1-(4-chlorophenyl)piperazine sulfate, and 2-chloro-4-methylphenylpiperazine hydrochloride.

[0013] In one embodiment, the concentration of the chlorophenylpiperazine salt is 0.1~2 mg / mL.

[0014] In a preferred embodiment, the chlorophenylpiperazine salt is selected from 1-(4-chlorophenyl)piperazine hydrochloride.

[0015] In one embodiment, the material of the substrate layer is selected from at least one of ITO (indium tin oxide), FTO (fluorine-doped tin oxide), AZO (aluminum-doped zinc oxide), and IZO (indium zinc oxide).

[0016] In a preferred embodiment, the substrate layer is made of ITO, which has a sheet resistance of 8Ω and a transmittance of 85%.

[0017] Specifically, ITO has a large bandgap, and selecting an ITO conductive substrate with the above specifications can provide high visible light transmittance and near-infrared reflectance, as well as very low resistivity, which can effectively improve conductivity.

[0018] In one embodiment, the hole transport layer is a self-assembled molecular (SAM) hole transport layer, and its material is selected from [4-(7H-dibenzo[c,g]carbazole-7-yl)butyl]phosphonic acid (4PADCB), phenylphosphonic acid (PPA), 4-methoxyphenylphosphonic acid (MPA), 3-thiophenephosphonic acid (TPA), N-ethylcarbazole-3-carboxylic acid, poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) (PEDOT:PSS), poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), NiO x At least one of CuI; the hole transport layer has a thickness of 5~50 nm.

[0019] Specifically, the hole transport layer (SAM) utilizes non-covalent interactions between molecules (such as hydrogen bonds, van der Waals forces, and π-π stacking) to spontaneously form ordered, dense monomolecular or multimolecular thin films on the substrate surface. These hole transport layer molecules typically have a structure of anchoring groups + conductive conjugated groups. The anchoring groups (such as phosphonic acid groups and carboxyl groups) form strong chemical bonds with the substrate surface for fixation, while the conjugated groups are responsible for efficient hole transport. Simultaneously, they suppress electron back migration and reduce the density of interface defect states. Choosing such a hole transport layer can suppress photoinduced halide segregation to enhance device stability, and it also possesses molecular designability, excellent mechanical flexibility, and is suitable for the charge separation and transport requirements of perovskite solar cells, as well as industrial production.

[0020] In one embodiment, the material of the electron transport layer is selected from at least one of fullerene (C60), methyl 6,6-phenyl-C61-butyrate (PCBM), isooctyl 6,6-phenyl-C71-butyrate (ICBA), C70, titanium dioxide (TiO2), tin dioxide (SnO2), zinc oxide (ZnO), titanium nitride (TiN), perylene diimide derivative (PDI), and naphthylene diimide derivative (NDI); the thickness of the electron transport layer is 10~50 nm.

[0021] Specifically, the electron transport layer has a wide band gap, a small refractive index, and a high electron mobility, which can promote the effective separation of electrons and holes, reduce charge recombination, and eliminate hysteresis.

[0022] In one embodiment, the material of the interface control layer is selected from at least one of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), 4,7-diphenyl-1,10-phenanthroline (BPhen), (2,2',2”-(1,3,5-triazine-2,4,6-triyl)tris(1-phenyl-1H-benzimidazole)) (TPBi), lithium fluoride (LiF), polyethylimine ethoxylate (PEIE), alumina (Al2O3), magnesium oxide (MgO), cesium carbonate (Cs2CO3), polyvinylpyrrolidone (PVP), and polymethyl methacrylate (PMMA); the thickness of the interface control layer is 1~20 nm.

[0023] Specifically, the interface control layer can enhance carrier transport, prevent dissociation of the perovskite crystal surface structure, and thus improve the stability of the device.

[0024] In one embodiment, the material of the electrode layer is selected from at least one of Ag, Au, Al, Cu, Cr-Au alloy, Ag-Au alloy, and Ag-Cu alloy; the thickness of the electrode layer is 50~100 nm.

[0025] Specifically, the aforementioned back electrode metal has good conductivity and stability. Selecting a metal of the aforementioned thickness as the back electrode can solve the problem of back electrode contact in traditional devices, thereby improving the efficiency and stability of the device.

[0026] According to a second aspect of this disclosure, a method for preparing the above-mentioned perovskite solar cell is provided, comprising the following steps: S1: Prepare a hole transport layer on the substrate; S2: Spin-coat the perovskite precursor solution onto the hole transport layer, and then anneal to obtain the perovskite light-absorbing layer. S3: A chlorophenylpiperazine salt solution is spin-coated onto the perovskite light-absorbing layer and then annealed to obtain a modified layer; S4: An electron transport layer, an interface control layer, and an electrode layer are sequentially prepared on the modified layer to obtain the perovskite solar cell.

[0027] In one embodiment, step S1 first involves ultrasonic cleaning, inert gas drying, and ultraviolet light irradiation of the substrate layer.

[0028] In one embodiment, step S1, which involves preparing the hole transport layer, includes: spin-coating the hole transport layer material onto the substrate layer and annealing it to obtain the hole transport layer; the spin-coating speed is 2000~4000 rpm and the time is 20~40s; the annealing temperature is 100~150℃ and the time is 10~30min.

[0029] In one embodiment, in step S2, the spin coating speed is 500~5000 rpm and the time is 20~45s; after the spin coating starts, an anti-solvent is added dropwise for anti-dissolution, and then annealed at 100~150℃ for 20~30min to obtain the perovskite light-absorbing layer.

[0030] Specifically, the antisolvent is selected from at least one of anhydrous diethyl ether, chlorobenzene, o-dichlorobenzene, dichloromethane, n-hexane, toluene, isopropanol, and ethyl acetate.

[0031] Specifically, spin coating under the aforementioned process parameters yields a film with uniform perovskite component distribution and suitable thickness, facilitating subsequent annealing. By using an anti-solvent for back-dissolution, the crystallization process of the solute in the perovskite precursor solution is promoted during solvent crystallization. Annealing at the aforementioned annealing temperature and time results in a stable perovskite film.

[0032] Specifically, the annealing atmosphere is an inert atmosphere.

[0033] In one embodiment, the spin coating speed in step S3 is 1000~6000 rpm and the time is 5~30s; the annealing temperature is 100~150℃ and the time is 3~30min.

[0034] Specifically, the annealing atmosphere is an inert atmosphere.

[0035] Specifically, spin-coating chlorophenylpiperazine salt within the above-mentioned range can yield a uniform and high-quality modified layer, which facilitates subsequent annealing.

[0036] In one embodiment, step S4 involves sequentially preparing the electron transport layer, the interface control layer, and the electrode layer using vapor deposition, wherein the vacuum degree of the vapor deposition is 1×10⁻⁶. -3 ~5×10 -4 Pa; the evaporation rate of the electron transport layer is 0.1~0.3 Å / s, the evaporation rate of the interface control layer is 0.05~0.2 Å / s, and the evaporation rate of the electrode layer is 0.5~3 Å / s.

[0037] According to one possible implementation of this disclosure, at least the following beneficial effects are achieved: 1. The chlorophenylpiperazine salt disclosed herein can induce perovskite surface reconstruction and secondary grain growth, resulting in increased film grain size, reduced grain boundaries, and vertical grain orientation. Simultaneously, it reduces residual stress in the film, significantly improving its uniformity and density, thus solving the problems of small grains, numerous defects, and uneven quality in perovskite layer preparation using the one-step spin-coating method. The chlorophenyl group effectively passivates the site vacancies of the X-position anion and the undercoordinated B-position cation. The piperazine group forms hydrogen bonds with the A-position cation, while the π-cation interaction induced by the benzene ring further immobilizes the A-position cation, inhibiting ion migration and reducing interface and bulk defects. Furthermore, it optimizes the energy level arrangement of the PVK / PEL interface, significantly reducing defect-assisted recombination and non-radiative recombination losses, and improving the film carrier lifetime.

[0038] 2. The efficiency of solar cell devices based on the prepared perovskite light-absorbing layer is further improved. The photoelectric conversion efficiency of both small-area devices and large-area modules is significantly improved, which can be used to match industrial production.

[0039] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of this disclosure, nor is it intended to limit the scope of this disclosure. Other features of this disclosure will become readily apparent from the following description. Attached Figure Description

[0040] The above and other objects, features, and advantages of this disclosure will become readily apparent from the following detailed description of exemplary embodiments, taken in conjunction with the accompanying drawings. Several embodiments of this disclosure are illustrated in the drawings by way of example and not limitation, in which: In the accompanying drawings, the same or corresponding reference numerals indicate the same or corresponding parts.

[0041] Figure 1 The current-voltage curves of the perovskite solar cells prepared in Example 1 and Comparative Example 1 of this disclosure are shown. Figure 2 The current-voltage curves of the perovskite solar cells prepared in Example 3 and Comparative Example 3 of this disclosure are shown. Figure 3 The current-voltage curves of the perovskite solar cells prepared in Example 2 and Comparative Example 2 of this disclosure are shown. Figure 4 SEM images of the perovskite light-absorbing layer surfaces prepared in Embodiment 1 and Comparative Example 1 of this disclosure are shown. Figure 5 SEM images of the perovskite light-absorbing layer surfaces prepared in Comparative Examples 1, 4, 1, 5, and 6 of this disclosure are shown. Figure 6 SEM images of cross sections of the perovskite light-absorbing layers prepared in Embodiment 1 and Comparative Example 1 of this disclosure are shown; Figure 7 The photoluminescence spectra of the perovskite light-absorbing layers prepared in Example 1 and Comparative Example 1 of this disclosure are shown; Figure 8 The delayed fluorescence spectra of the perovskite light-absorbing layers prepared in Example 1 and Comparative Example 1 of this disclosure are shown. Figure 9 The slightly incident wide-angle X-ray scattering spectra of the perovskite light-absorbing layers prepared in Example 1 and Comparative Example 1 of this disclosure are shown; Figure 10 Linear fitting plots of the 2θ-sin2φ curves of the perovskite light-absorbing layers prepared in Example 1 and Comparative Example 1 of this disclosure are shown; Figure 11 The perovskite solar cells prepared in Embodiment 1 and Comparative Example 1 of this disclosure are shown. V OC , J SC Relationship between light intensity and illumination. Detailed Implementation

[0042] To make the objectives, features, and advantages of this disclosure more apparent and understandable, the technical solutions in the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this disclosure, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0043] Example 1 This embodiment fabricates a perovskite solar cell, as detailed below: (1) Select an ITO conductive glass with a sheet resistance of 8Ω, a transmittance of 85%, and a size of 1.96cm×1.96cm as the substrate. Before use, the ITO conductive substrate needs to be ultrasonically cleaned with deionized water and isopropanol, dried with nitrogen, and then treated with ultraviolet light for 30 minutes.

[0044] (2) Dissolve 1.0 mg of [4-(7H-dibenzo[c,g]carbazole-7-yl)butyl]phosphonic acid (4PADCB) in 2 mL of ethanol to prepare a hole transport layer solution. Then, add 80 μL of the hole transport layer solution to an ITO conductive substrate, spin-coat at 3000 rpm for 30 s to deposit an ultrathin layer of 4PADCB, and then anneal at 100 °C for 10 min to obtain the hole transport layer.

[0045] (3) The prepared perovskite precursor solution was dropped onto the hole transport layer and spin-coated at 4000 rpm for 30 s. 500 μL of anhydrous diethyl ether (DE) was dropped onto the wet perovskite film 15 s after spin-coating to dissolve it. Then, the film was annealed at 100 °C for 30 min to obtain the perovskite light-absorbing layer FA. 0.85 MA 0.1 Cs 0.05 PbI3.

[0046] (4) Dissolve 1-(4-chlorophenyl)piperazine hydrochloride (4CPPDCl) in a mixed solution of isopropanol (IPA) / chlorobenzene (CB) to obtain a 4CPPDCl passivation layer solution with a concentration of 1 mg / mL. Spin-coat the passivation layer solution onto the perovskite light-absorbing layer at a speed of 3000 rpm for 30 s, and then anneal at 100 °C for 5 min to obtain the modified layer.

[0047] (5) Place the sample prepared in step (4) into a vacuum evaporation coating equipment, and the vacuum degree reaches 5×10 -4 After Pa, C60 was deposited at an evaporation rate of 0.2 Å / s to obtain an electron transport layer with a thickness of 25 nm.

[0048] (6) Place the sample prepared in step (5) into a vacuum evaporation coating equipment, and the vacuum degree reaches 5×10 -4 After Pa, a BCP interface control layer with a thickness of 6 nm was deposited at an evaporation rate of 0.2 Å / s.

[0049] (7) Place the sample prepared in step (6) into a vacuum evaporation coating equipment, and the vacuum degree reaches 5×10 -4 After Pa, metallic Ag was deposited at an evaporation rate of 2 Å / s to obtain an Ag electrode coating with a thickness of 100 nm.

[0050] The perovskite solar cell device fabricated using the above steps has an effective area of ​​0.06 cm². 2 .

[0051] Example 2 This embodiment fabricates a perovskite solar cell, as detailed below: (1) Select an ITO conductive glass substrate with a sheet resistance of 8Ω, a transmittance of 85%, and a size of 5cm×5cm. After laser scribing P1, it is ultrasonically cleaned with deionized water and isopropanol, dried with nitrogen, and then treated with ultraviolet light for 30min.

[0052] (2) Dissolve 1.0 mg of 4PADCB in 2 mL of ethanol to prepare a hole transport layer solution. Then add 80 μL of hole transport layer solution to an ITO conductive substrate, spin coat at 3000 rpm for 30 s to deposit an ultrathin layer of 4PADCB, and then anneal at 100 °C for 10 min to obtain the hole transport layer.

[0053] (3) The prepared perovskite precursor solution was dropped onto the hole transport layer and spin-coated at 4000 rpm for 30 s. 15 s after the spin-coating was started, 2.5 mL of anhydrous diethyl ether (DE) was dropped onto the wet perovskite film for back dissolution. Then, the film was annealed at 100 °C for 30 min to obtain the perovskite light-absorbing layer FA. 0.85 MA 0.1 Cs 0.05 PbI3.

[0054] (4) Dissolve 4CPPDCl in a mixed solution of isopropanol / chlorobenzene to obtain a 4CPPDCl passivation layer solution with a concentration of 1 mg / mL. Spin coat the passivation layer solution onto the perovskite light-absorbing layer at a speed of 3000 rpm for 30 s, and then anneal at 100 °C for 5 min to obtain the modified layer.

[0055] (5) Place the sample prepared in step (4) into a vacuum evaporation coating equipment, and the vacuum degree reaches 5×10 -4 After Pa, C60 was deposited at an evaporation rate of 0.2 Å / s to obtain an electron transport layer with a thickness of 25 nm.

[0056] (6) Place the sample prepared in step (5) into a vacuum evaporation coating equipment, and the vacuum degree reaches 5×10 -4 After Pa, a BCP interface control layer with a thickness of 6 nm was deposited at an evaporation rate of 0.2 Å / s, and then P2 was processed by laser scribing.

[0057] (7) Place the sample prepared in step (6) into a vacuum evaporation coating equipment, and the vacuum degree reaches 5×10 -4 After Pa, metallic Ag was deposited at an evaporation rate of 2 Å / s to obtain an Ag electrode coating with a thickness of 100 nm, which was then laser-etched into P3 and P4.

[0058] The perovskite solar cell device fabricated using the above steps has an effective area of ​​10.24 cm². 2 .

[0059] Example 3 This embodiment fabricates a perovskite solar cell, as detailed below: (1) Select an ITO conductive glass with a sheet resistance of 8Ω, a transmittance of 85%, and a size of 1.96cm×1.96cm as the substrate. Before use, the ITO conductive substrate needs to be ultrasonically cleaned with deionized water and isopropanol, dried with nitrogen, and then treated with ultraviolet light for 30 minutes.

[0060] (2) Dissolve 1.0 mg of 4PADCB in 2 mL of ethanol to prepare a hole transport layer solution. Then add 80 μL of hole transport layer solution to an ITO conductive substrate, spin coat at 3000 rpm for 30 s to deposit an ultrathin layer of 4PADCB, and then anneal at 100 °C for 10 min to obtain the hole transport layer.

[0061] (3) The prepared perovskite precursor solution was dropped onto the hole transport layer and spin-coated at 4000 rpm for 30 s. 500 μL of anhydrous diethyl ether (DE) was dropped onto the wet perovskite film 15 s after spin-coating to dissolve it. Then, the film was annealed at 100 °C for 30 min to obtain the perovskite light-absorbing layer Cs. 0.05 (FA 0.96 MA 0.04 ) 0.95 (I 0.95 Br 0.05 3.

[0062] (4) Dissolve 4CPPDCl in a mixed solution of isopropanol / chlorobenzene to obtain a 4CPPDCl passivation layer solution with a concentration of 1 mg / mL. Spin coat the passivation layer solution onto the perovskite light-absorbing layer at a speed of 3000 rpm for 30 s, and then anneal at 100 °C for 5 min to obtain the modified layer.

[0063] (5) Place the sample prepared in step (4) into a vacuum evaporation coating equipment, and the vacuum degree reaches 5×10 -4 After Pa, C60 was deposited at an evaporation rate of 0.2 Å / s to obtain an electron transport layer with a thickness of 25 nm.

[0064] (6) Place the sample prepared in step (5) into a vacuum evaporation coating equipment, and the vacuum degree reaches 5×10 -4 After Pa, a BCP interface control layer with a thickness of 6 nm was deposited at an evaporation rate of 0.2 Å / s.

[0065] (7) Place the sample prepared in step (6) into a vacuum evaporation coating equipment, and the vacuum degree reaches 5×10 -4 After Pa, metallic Ag was deposited at an evaporation rate of 2 Å / s to obtain an Ag electrode coating with a thickness of 100 nm.

[0066] The perovskite solar cell device fabricated using the above steps has an effective area of ​​0.06 cm². 2 .

[0067] Example 4 This embodiment prepares a perovskite solar cell. The remaining steps are the same as in embodiment 1, and will not be repeated here. However, in step (4) of this embodiment, the concentration of the 4CPPDCl passivation layer solution is 0.5 mg / mL.

[0068] Example 5 This embodiment prepares a perovskite solar cell. The remaining steps are the same as in embodiment 1, and will not be repeated here. However, in step (4) of this embodiment, the concentration of the 4CPPDCl passivation layer solution is 1.5 mg / mL.

[0069] Example 6 This embodiment prepares a perovskite solar cell. The remaining steps are the same as in embodiment 1, and will not be repeated here. However, in step (4) of this embodiment, the concentration of the 4CPPDCl passivation layer solution is 2.0 mg / mL.

[0070] Comparative Example 1 This comparative example prepared a perovskite solar cell. The difference between this comparative example and Example 1 is that no modification layer was prepared, i.e., no step (4) was prepared. The rest is the same as Example 1, and will not be repeated here.

[0071] Comparative Example 2 This comparative example prepared a perovskite solar cell. The difference between this comparative example and Example 2 is that no modification layer was prepared, i.e., no step (4) was prepared. The rest is the same as Example 2, and will not be repeated here.

[0072] Comparative Example 3 This comparative example prepared a perovskite solar cell. The difference between this comparative example and Example 3 is that no modification layer was prepared, i.e., no step (4) was prepared. The rest is the same as Example 3, and will not be repeated here.

[0073] Test case 1. The photoelectric performance of the perovskite solar cells prepared in Examples 1-3 and Comparative Examples 1-3 was analyzed.

[0074] Under simulated AM1.5 sunlight (light intensity 100mW / cm²), 2 The perovskite solar cell devices prepared in Examples 1 and 3, and Comparative Examples 1 and 3 were tested respectively (effective device area: 0.06 cm²). 2 The current-voltage curves (JV) of the sample were obtained by reverse scanning from 1.5V to 0.5V at a scan rate of 20mV / s. The results are shown in Tables 1 and 2. Figure 1 , Figure 2 .

[0075] Table 1

[0076] Table 2

[0077] Under simulated AM1.5 sunlight conditions (light intensity 100 mW / cm²), 2 The perovskite solar cells prepared in Example 2 and Comparative Example 2 were tested respectively (effective device area: 10.24 cm²). 2 The current-voltage curves (JV) of the micro-components were obtained by reverse scanning from 6V to 0.5V at a scan rate of 20mV / s. The results are shown in Table 3. Figure 3 .

[0078] Table 3

[0079] From Table 1, Table 2, Table 3 and Figure 1 , Figure 2 , Figure 3 It can be seen that the short-circuit current density of the perovskite solar cell after treatment with 4CPPDCl is ( J SC ), open circuit voltage ( V OC Both the fill factor (FF) and fill power (F) were improved, with the battery device in Example 1 treated with 4CPPDCl showing an effective area of ​​0.06 cm². 2The photoelectric efficiency (26.28%) of the battery device in Example 3 (without 4CPPDCl treatment) is higher than that of the battery device in Comparative Example 1 (23.67%). The battery device in Example 3 treated with 4CPPDCl (effective area: 0.06 cm²) 2 The photoelectric efficiency (26.62%) of the device was higher than that of the untreated battery device in Comparative Example 3 (24.29%); meanwhile, the micro-component treated with 4CPPDCl in Example 2 (pore area: 10.24 cm²) was also higher. 2 The photoelectric efficiency of the micro-module (22.61%) was higher than that of the micro-module in Comparative Example 2 without 4CPPDCl treatment (19.97%), proving that 4CPPDCl treatment can improve the photoelectric performance of perovskite solar cells.

[0080] 2. The microstructure of the perovskite light-absorbing thin films prepared in the examples and comparative examples was characterized using scanning electron microscopy (SEM).

[0081] Figure 4 (a) is a SEM image of the surface of the perovskite light-absorbing layer prepared in Comparative Example 1 without 4CPPDCl modification. Figure 4 (b) is a SEM image of the surface of the perovskite light-absorbing layer modified with 4CPPDCl prepared in Example 1. Figure 5 SEM images of the perovskite absorbing layer without 4CPPDCl modification prepared in Comparative Example 1, and the perovskite absorbing layers modified with 4CPPDCl prepared in Examples 4 (4CPPDCl concentration of 0.5 mg / mL), 1 (4CPPDCl concentration of 1.0 mg / mL), 5 (4CPPDCl concentration of 1.5 mg / mL), and 6 (4CPPDCl concentration of 2.0 mg / mL). (Source: [Insert SEM images here]) Figure 4 A comparison of (a) and (b) shows that the perovskite film modified with 4CPPDCl has larger grains and fewer grain boundaries; Figure 5 It can be seen that as the concentration of 4CPPDCl increases, the grain size shows a trend of increasing and then stagnating, and the material aggregation leads to more shadows.

[0082] Figure 6 The images show SEM images of the cross-sections of the perovskite light-absorbing layer prepared in Comparative Example 1 without 4CPPDCl modification and the perovskite light-absorbing layer prepared in Example 1 with 4CPPDCl modification. It can be seen that the perovskite light-absorbing layer prepared in Example 1 with 4CPPDCl modification has significantly larger grains in cross-section, and more grains exhibit vertical orientation, indicating that 4CPPDCl modification can effectively control the crystallization orientation and improve the morphology of the film.

[0083] 3. The photoluminescence (PL) spectra of the perovskite light-absorbing thin films prepared in Example 1 and Comparative Example 1 were analyzed to characterize the defect density, such as... Figure 7 The images show the photoluminescence spectra (PL spectra) of the perovskite absorber layer prepared in Comparative Example 1 without 4CPPDCl modification and the perovskite absorber layer prepared in Example 1 with 4CPPDCl modification. Figure 8 The images show the delayed fluorescence (TRPL) spectra of the perovskite absorbing layer prepared in Comparative Example 1 without 4CPPDCl modification and the perovskite absorbing layer prepared in Example 1 with 4CPPDCl modification.

[0084] Figure 7 The results show that the emission intensity of the perovskite light-absorbing layer film modified with 4CPPDCl is much higher than that of the perovskite light-absorbing layer film without 4CPPDCl modification. This can be attributed to the fact that the modification effect of the additive improves the film formation quality of the perovskite film, increases the grain size of the film, and suppresses nonradiative transitions. Figure 8 The results show that the average lifetime of the perovskite film without 4CPPDCl modification is 327.51 ns, while the average lifetime of the perovskite film modified with 4CPPDCl increases to 950.11 ns. This indicates that 4CPPDCl modification can effectively passivate defects in the film and improve the quality of the perovskite film.

[0085] 4. The perovskite light-absorbing thin films prepared in Example 1 and Comparative Example 1 were analyzed using slightly incident wide-angle X-ray scattering. Figure 9 The images show the slightly incident wide-angle X-ray scattering spectra of the perovskite light-absorbing layer prepared in Comparative Example 1 without 4CPPDCl modification and the perovskite light-absorbing layer prepared in Example 1 with 4CPPDCl modification.

[0086] Figure 9 The results show that 4CPPDCl modification has a certain regulatory effect on the crystallization of perovskite films, causing perovskite to preferentially grow along the (100) plane.

[0087] Figure 10 The figure shown is a linear fitting diagram of the 2θ-sin2φ curve of the perovskite light-absorbing layer. It can be seen that the residual stress of the perovskite film modified with 4CPPDCl is significantly reduced.

[0088] 5. The performance of the perovskite solar cell devices prepared in Example 1 and Comparative Example 1 was characterized.

[0089] Figure 11 The perovskite solar cells prepared in Comparative Example 1 without 4CPPDCl modification and those prepared in Example 1 with 4CPPDCl modification are compared. V OC , J SC Relationship between light intensity and illumination. Figure 11 The results show that the slope of the perovskite solar cell device modified with 4CPPDCl prepared in Example 1 is less than that of the perovskite solar cell device without 4CPPDCl modification prepared in Comparative Example 1, indicating that the defect-assisted recombination of the perovskite solar cell device modified with 4CPPDCl prepared in Example 1 is significantly reduced.

[0090] It should be understood that the various forms of processes shown above can be used to rearrange, add, or delete steps. For example, the steps described in this disclosure can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this disclosure can be achieved, and this is not limited herein.

[0091] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this disclosure, "a plurality of" means two or more, unless otherwise explicitly specified.

[0092] The above description is merely a specific embodiment of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

Claims

1. A perovskite solar cell, characterized in that, The perovskite solar cell comprises, from bottom to top, a substrate layer, a hole transport layer, a perovskite light-absorbing layer, a modification layer, an electron transport layer, an interface control layer, and an electrode layer; the material of the modification layer is chlorophenylpiperazine salt.

2. The perovskite solar cell according to claim 1, characterized in that, The chlorophenylpiperazine salt is selected from at least one of 1-(4-chlorophenyl)piperazine hydrochloride, 1-(2-chlorophenyl)piperazine hydrochloride, 1-(3-chlorophenyl)piperazine hydrobromide, 1-(4-chlorophenyl)piperazine nitrate, 1-(4-chlorophenyl)piperazine sulfate, and 2-chloro-4-methylphenylpiperazine hydrochloride; the concentration of the chlorophenylpiperazine salt is 0.1~2 mg / mL.

3. The perovskite solar cell according to claim 1, characterized in that, The chemical formula of the perovskite structure in the perovskite light-absorbing layer is ABX3, wherein A is selected from at least one of methylammonium cation, formamidinium cation, and cesium ion; B is selected from at least one of lead ion and tin ion; and X is selected from at least one of chloride ion, bromide ion, iodide ion, and thiocyanate ion.

4. The perovskite solar cell according to claim 3, characterized in that, The chemical formula of the perovskite structure in the perovskite light-absorbing layer is FA. 1-x-y MA x Cs y Pb(I 1-z Br z )3, where x=0~1, y=0~1, z=0~1.

5. The perovskite solar cell according to claim 1, characterized in that, In the perovskite solar cell, the material of the substrate layer is selected from at least one of ITO, FTO, AZO, and IZO; The hole transport layer is a molecularly self-assembled hole transport layer, and its materials are selected from 4PADCB, PPA, MPA, TPA, N-ethylcarbazole-3-carboxylic acid, PEDOT:PSS, PTAA, and NiO. x At least one of CuI; the hole transport layer has a thickness of 5~50 nm; The electron transport layer is made of at least one material selected from C60, PCBM, ICBA, C70, TiO2, SnO2, ZnO, TiN, PDI, and NDI; the thickness of the electron transport layer is 10~50 nm. The material of the interface control layer is selected from at least one of BCP, BPhen, TPBi, LiF, PEIE, Al2O3, MgO, Cs2CO3, PVP, and PMMA; the thickness of the interface control layer is 1~20nm. The electrode layer is made of at least one of Ag, Au, Al, Cu, Cr-Au alloy, Ag-Au alloy, and Ag-Cu alloy; the thickness of the electrode layer is 50~100 nm.

6. The method for preparing a perovskite solar cell according to any one of claims 1 to 5, characterized in that, Includes the following steps: S1: Prepare a hole transport layer on the substrate; S2: Spin-coat the perovskite precursor solution onto the hole transport layer, and then anneal to obtain the perovskite light-absorbing layer. S3: A chlorophenylpiperazine salt solution is spin-coated onto the perovskite light-absorbing layer and then annealed to obtain a modified layer; S4: An electron transport layer, an interface control layer, and an electrode layer are sequentially prepared on the modified layer to obtain the perovskite solar cell.

7. The preparation method according to claim 6, characterized in that, Step S1, which involves preparing the hole transport layer, includes: spin-coating the hole transport layer material onto the substrate layer and annealing it to obtain the hole transport layer; the spin-coating speed is 2000~4000 rpm and the time is 20~40s; the annealing temperature is 100~150℃ and the time is 10~30min.

8. The preparation method according to claim 6, characterized in that, In step S2, the spin coating speed is 500~5000 rpm and the time is 20~45s; 10~25s after the start of spin coating, an anti-solvent is added for anti-dissolution, and then annealed at 100~150℃ for 20~30min to obtain the perovskite light-absorbing layer. The antisolvent is selected from at least one of anhydrous diethyl ether, chlorobenzene, o-dichlorobenzene, dichloromethane, n-hexane, toluene, isopropanol, and ethyl acetate.

9. The preparation method according to claim 6, characterized in that, In step S3, the spin coating speed is 1000~6000 rpm and the time is 5~30s; the annealing temperature is 100~150℃ and the time is 3~30min.

10. The preparation method according to claim 6, characterized in that, Step S4 involves sequentially preparing the electron transport layer, the interface control layer, and the electrode layer using vapor deposition, with a vacuum degree of 1×10⁻⁶. -3 ~5×10 -4 Pa; the evaporation rate of the electron transport layer is 0.1~0.3 Å / s, the evaporation rate of the interface control layer is 0.05~0.2 Å / s, and the evaporation rate of the electrode layer is 0.5~3 Å / s.

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