An organic-inorganic perovskite solar cell with oriented intrinsic dipoles and its fabrication method.

Abstract

This invention provides an organic-inorganic perovskite solar cell with intrinsically aligned perovskite dipoles, comprising, from bottom to top, a conductive substrate, an electron transport layer, an intrinsically aligned perovskite thin film, a hole transport layer, and a metal counter electrode; or, comprising, from bottom to top, a conductive substrate, an intrinsically aligned perovskite thin film, a hole transport layer, and a metal counter electrode. The preparation method of the intrinsically aligned perovskite thin film includes the steps of: adding sulfonamide to a perovskite precursor solution and mixing thoroughly; spin-coating the mixture onto the electron transport layer or conductive substrate and annealing. This invention utilizes volatile, highly polar small-molecule sulfonamide as an initiator for the intrinsically aligned perovskite dipoles, inducing the reorientation of the perovskite dipoles, thereby achieving vertical orientation polarization of the perovskite thin film and effectively improving the photoelectric conversion efficiency and stability of the solar cell.

Description

Technical Field

[0001] This invention relates to an organic-inorganic perovskite solar cell with oriented perovskite intrinsic dipoles and its fabrication method, belonging to the field of perovskite solar cell technology. Background Technology

[0002] Organic-inorganic hybrid perovskites have become one of the most promising semiconductor materials due to their advantages such as high absorption coefficient, tunable bandgap, low cost, and ease of fabrication. To date, the highest certified photoelectric conversion efficiency of perovskite solar cells has reached 25.7%, comparable to high-performance silicon-based solar cells. However, due to the polycrystalline nature of perovskite films prepared by solution methods, positively or negatively charged defects at grain boundaries and surfaces attract electrons or holes through Coulomb interactions, inevitably causing severe nonradiative recombination. Therefore, enhancing the directional extraction and transport capabilities of charge carriers is a necessary approach to suppress open-circuit voltage loss and maintain long-term efficient and stable output of the device.

[0003] Studies based on methylamine hybrid perovskites have shown that the rotation of methylamine ions with strong dipole moments within the lattice creates localized spontaneous polarization within the thin film, and the resulting changes in the local electrostatic field affect carrier transport. However, the orientation of localized polarization in perovskites is usually disordered, resulting in negligible macroscopic net polarization and a nearly flat energy band structure. On the one hand, the flat band structure is not conducive to the directional transport of extracted carriers within the photoactive layer, causing unnecessary quenching of photogenerated carriers within the layer. On the other hand, the energy level mismatch between the perovskite layer and the charge transport layer exacerbates the recombination loss at the interface, limiting further performance improvements. Furthermore, the fabrication of the electron transport layer in perovskite devices requires high temperatures and complex processes. Perovskite solar cells without an electron transport layer are more competitive in the commercialization of perovskite solar cells due to their lower manufacturing costs and greater application flexibility. However, the energy level mismatch between the perovskite layer and the conductive substrate causes severe recombination losses, resulting in lower photoelectric conversion efficiency for perovskite solar cells without an electron transport layer.

[0004] To address the aforementioned problems, this invention is proposed. Summary of the Invention

[0005] To address the problems of interfacial energy level mismatch and low carrier extraction efficiency in perovskite solar cells, this invention proposes an organic-inorganic perovskite solar cell with oriented perovskite intrinsic dipoles and its fabrication method. This invention utilizes volatile inorganic small molecule sulfonamides as initiators for the oriented alignment of perovskite intrinsic dipoles, inducing the reorientation of the perovskite dipoles and thus achieving vertical orientation polarization of the perovskite thin film. The vertically aligned dipoles determine the gradient band structure of the light-absorbing layer in the perovskite solar cell and the energy level alignment at the interface, effectively enhancing the built-in electric field and suppressing nonradiative recombination. Furthermore, the change in the local dielectric field of the thin film after the oriented alignment of the perovskite intrinsic dipoles significantly reduces the exciton binding energy, which is beneficial for efficient carrier extraction and transport. The perovskite dipole modulation strategy of this invention effectively improves the photoelectric conversion efficiency and stability of organic-inorganic perovskite solar cells.

[0006] The technical solution of the present invention is as follows:

[0007] An organic-inorganic perovskite solar cell with oriented perovskite intrinsic dipoles, characterized in that,

[0008] It includes, from bottom to top, a conductive substrate, an electron transport layer, a perovskite thin film with intrinsically aligned dipoles, a hole transport layer, and a metal counter electrode;

[0009] or,

[0010] It includes a conductive substrate arranged from bottom to top, a perovskite thin film with intrinsic dipoles oriented, a hole transport layer, and a metal counter electrode;

[0011] The method for preparing the intrinsically dipole-oriented perovskite thin film includes the following steps: adding sulfonamide to a perovskite precursor solution and mixing it evenly to obtain a spin-coating solution; spin-coating the solution onto an electron transport layer or a conductive substrate and annealing it to obtain the intrinsically dipole-oriented perovskite thin film.

[0012] According to the present invention, the conductive substrate, electron transport layer, hole transport layer, and metal counter electrode can be obtained according to the prior art.

[0013] According to a preferred embodiment of the present invention, the conductive substrate is a fluorine-doped tin oxide (FTO) transparent conductive substrate with a thickness of 140-160 nm.

[0014] According to a preferred embodiment of the present invention, the electron transport layer is dense titanium dioxide with a thickness of 20-30 nm.

[0015] According to a preferred embodiment of the present invention, the hole transport layer is 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene (Spiro-OMeTAD) with a thickness of 200-250 nm.

[0016] According to a preferred embodiment of the present invention, the metal counter electrode layer is a silver (Ag) counter electrode with a thickness of 100-140 nm.

[0017] According to a preferred embodiment of the present invention, the thickness of the intrinsically dipole-oriented perovskite thin film is 550-600 nm; the intrinsically dipole-oriented perovskite thin film has a gradient band structure, transitioning from p-type semiconductor to n-type semiconductor from bottom to top.

[0018] According to a preferred embodiment of the present invention, the preparation of the perovskite precursor solution comprises the steps of dissolving formamidine lead iodide (FAPbI3) single crystal powder and methylamine chloride (MACl) in a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide to obtain the perovskite precursor solution. Preferably, the molar ratio of formamidine lead iodide single crystal powder to methylamine chloride is 1:0.35; the volume ratio of N,N-dimethylformamide to dimethyl sulfoxide in the mixed solvent is 3-5:1; and the concentration of formamidine lead iodide single crystal powder in the mixed solvent is 1.6-1.8 mol / L.

[0019] Preferably, the preparation method of formamidine lead-iodine single crystal powder includes the following steps: mixing lead acetate and formamidine acetate in a molar ratio of 3:4, adding them to an aqueous solution of hydroiodic acid, keeping the mixture at 80-90℃ for 2-4 hours, and then washing and annealing to obtain formamidine lead-iodine single crystal powder; the concentration of the aqueous solution of hydroiodic acid is 55-58 wt%; the annealing temperature is 150-180℃, and the treatment time is 12-24 hours.

[0020] According to a preferred embodiment of the present invention, the molar ratio of formamidinium lead iodine in the sulfonamide and perovskite precursor solution is 0.02-0.08:1, preferably 0.04:1.

[0021] According to a preferred embodiment of the present invention, the spin coating parameters are: a rotation speed of 5000-6000 rpm, a spin coating time of 40-50 seconds, and the addition of diethyl ether as an anti-solvent at the 10th second after the start of spin coating, wherein the volume ratio of diethyl ether to spin coating solution is 10-13:1.

[0022] According to a preferred embodiment of the present invention, the annealing temperature is 100-160°C, and the annealing time is 10-15 minutes. More preferably, the annealing temperature is 140-160°C.

[0023] According to a preferred embodiment of the present invention, both the spin coating and annealing processes must be carried out in a protective gas atmosphere; the protective gas is nitrogen.

[0024] According to the present invention, the perovskite thin film with intrinsically oriented dipoles is a formamidinium / methylamine lead iodide-based perovskite.

[0025] The method for fabricating the above-mentioned organic-inorganic perovskite solar cell with intrinsically aligned perovskite dipoles includes the following steps:

[0026] (1) Pretreatment of conductive substrate;

[0027] (2) An electron transport layer is prepared on a conductive substrate, and then an intrinsic dipole-oriented perovskite thin film is prepared on the electron transport layer; or, an intrinsic dipole-oriented perovskite thin film is prepared directly on a conductive substrate.

[0028] (3) A hole transport layer is prepared on a perovskite thin film with intrinsic dipole orientation;

[0029] (4) Fabricate a metal counter electrode on the hole transport layer.

[0030] According to the present invention, steps (1), (2) the electron transport layer, (3), and (4) can be prepared using existing technologies.

[0031] According to a preferred embodiment of the present invention, in step (1), the pretreatment method for the conductive substrate includes the following steps: ultrasonically cleaning the conductive substrate sequentially in deionized water, isopropanol, and ethanol, and drying it with nitrogen gas; then performing ultraviolet ozone treatment. Preferably, the ultrasonic cleaning time in each solvent is 10-20 minutes; the ultraviolet ozone treatment time is 10-30 minutes.

[0032] According to a preferred embodiment of the present invention, step (2) of the method for preparing an electron transport layer on a conductive substrate includes the steps of immersing the conductive substrate in an aqueous solution of titanium tetrachloride (TiCl4), and then washing, drying, and annealing at high temperature to obtain the electron transport layer.

[0033] Preferably, the concentration of the TiCl4 aqueous solution is 200-250 mmol / L. The immersion temperature is 65-75℃, and the immersion time is 55-65 min. The high-temperature annealing treatment temperature is 180-200℃, the treatment time is 30-60 min, and the treatment atmosphere is air.

[0034] According to a preferred embodiment of the present invention, in step (3), the method for preparing the hole transport layer includes the following steps: mixing Spiro-OMeTAD, chlorobenzene, 4-tert-butylpyridine, lithium bis(trifluoromethane)sulfonylimide acetonitrile solution, and FK209(4-tert-butyl-2-(1H-pyrazol-1-yl)pyridine]cobalt(III)) acetonitrile solution, stirring thoroughly to dissolve and obtain a doped Spiro-OMeTAD solution; then spin-coating the doped Spiro-OMeTAD solution onto a perovskite film with intrinsically dipole oriented alignment, and drying to obtain a hole transport layer. The mass-to-volume ratio of Spiro-OMeTAD to chlorobenzene is 90:1 mg / mL. The concentration of the lithium bis(trifluoromethane)sulfonylimide acetonitrile solution is 500-540 mg / mL, and the concentration of the FK209 acetonitrile solution is 350-400 mg / mL. The volume ratio of chlorobenzene, 4-tert-butylpyridine, lithium bis(trifluoromethane)sulfonylimide acetonitrile solution, and FK209 acetonitrile solution is 1000:39:23:10. The spin-coating speed is 3000-4000 rpm, and the spin-coating time is 20-30 seconds.

[0035] According to a preferred embodiment of the present invention, in step (4), thermal evaporation is performed at a vacuum level of less than 1*10. -4 Pa below, with The evaporation rate allows the metal electrode to be deposited on the hole transport layer.

[0036] The technical features and beneficial effects of this invention are as follows:

[0037] 1. This invention uses sulfonamide, a volatile pure inorganic molecule, as an initiator to regulate perovskite crystallization. This initiator transforms from an amide state to a polar state under the induction of a polar solvent and possesses an extremely strong molecular dipole moment. Therefore, it is added to the perovskite precursor solution to induce the directional alignment of intrinsic dipoles in the perovskite film. Currently available sulfonamide analogs for regulating perovskite are mostly organic additives that passivate film defects through Lewis acid-base coordination to improve device performance. Therefore, the added additives remain on the final film, and the resulting low dielectric constant molecules are detrimental to the effective collection of charge carriers during long-term stable operation of the device. In contrast, the sulfonamide used in this invention is an inorganic small molecule that completely volatilizes from the film after annealing, without adversely affecting device performance. Furthermore, its mechanism of action lies in inducing the directional alignment of intrinsic dipoles in the perovskite, further stimulating the intrinsic advantages of the perovskite film.

[0038] 2. The polar molecule crystallization control strategy employed in this invention effectively induces the vertical orientation rearrangement of intrinsic dipoles in perovskite. Compared to commonly used methods induced by external bias voltage, this strategy avoids irreversible damage to the film caused by the external electric field. This strategy yields perovskite films with high crystallinity while inducing directional polarization.

[0039] 3. This invention aims to further enhance the inherent advantages of perovskite. The key to this invention is the successful induction of the directional arrangement of intrinsic dipoles in the perovskite thin film. The vertically aligned dipoles optimize the device's band structure, which is crucial for improving device performance. This invention successfully induced the directional arrangement of intrinsic dipoles in perovskite by introducing highly polar volatile small molecules. It effectively modulates the perovskite band structure, which is key to carrier extraction and transport in perovskite devices. This invention successfully modulates the gradient band structure of the perovskite thin film, resulting in an electric field direction consistent with the built-in electric field. This enhanced built-in electric field promotes efficient carrier extraction and transport, and can be effectively applied to perovskite solar cells and other photovoltaic devices.

[0040] 4. In this invention, the reoriented dipoles alter the local dielectric field inside the perovskite thin film, thereby effectively reducing the exciton binding energy and enhancing the carrier mobility, extending the carrier lifetime, and achieving an ultra-long carrier diffusion distance of more than 1700 nm.

[0041] 5. In this invention, the dipole rearrangement improves the carrier dynamics of perovskite solar cells, thereby increasing the photoelectric conversion efficiency of the resulting nip structure based on the TiO2 electron transport layer from 21.61% to 23.84%. Furthermore, it exhibits good stability; the unencapsulated device retains 92% of its initial efficiency after 1080 hours of storage under environmental conditions. The sulfonamide, acting as an initiator, completely volatilizes after film annealing, and the improved device performance stems from the enhancement of the intrinsic properties of the perovskite.

[0042] 6. The fabrication of the electron transport layer in perovskite devices requires high temperatures and complex processes. Therefore, perovskite solar cells without an electron transport layer are more competitive in the commercialization of perovskite solar cells. However, due to the energy level mismatch at the interface between the perovskite and the conductive substrate, the efficiency of existing perovskite solar cells without an electron transport layer is relatively low. This invention fabricates a perovskite solar cell without an electron transport layer. Due to the gradient band structure formed by the directional alignment of intrinsic dipoles, improved interface energy level alignment, and efficient carrier extraction and transport, the device with an electron transport layer achieves a photoelectric conversion efficiency of 20.37%, which is one of the highest efficiencies of perovskite solar cells without an electron transport layer to date. Attached Figure Description

[0043] Figure 1 The images are scanning electron microscope (SEM) images of the organic-inorganic perovskite thin films prepared in Examples 1(c), 3(b), 4(d) and Comparative Example 1(a) of the present invention.

[0044] Figure 2The piezoelectric microscopy (PFM) phase images of the organic-inorganic perovskite thin films prepared in Example 1(b) and Comparative Example 1(a) of the present invention are shown, with the scale bar length being 2 μm.

[0045] Figure 3 Ultraviolet photoelectron spectra (UPS) of organic-inorganic perovskite films prepared in Example 1(b) and Comparative Example 1(a) of the present invention at different depths.

[0046] Figure 4 The structural model and current density-voltage curve of the solar cell prepared in Example 1 of the present invention are shown.

[0047] Figure 5 The stability test results are shown for the solar cells prepared in Example 1 and Comparative Example 1 of this invention.

[0048] Figure 6 The structural model and current density-voltage curve of the solar cell prepared in Example 2 of the present invention are shown.

[0049] Figure 7 The stability test results are shown for the solar cells prepared in Example 2 and Comparative Example 2 of this invention. Detailed Implementation

[0050] The present invention will be further described below through specific embodiments, but is not limited thereto.

[0051] Unless otherwise specified, all raw materials used in the embodiments are conventional raw materials that can be purchased commercially; unless otherwise specified, all methods used in the embodiments are existing technologies.

[0052] Example 1

[0053] A method for fabricating an organic-inorganic perovskite solar cell with intrinsically aligned perovskite dipoles includes the following steps:

[0054] (1): FTO transparent conductive substrate (length × width: 19 × 24 mm) 2 The conductive substrate (with a thickness of 150 nm) was ultrasonically cleaned sequentially in deionized water, isopropanol, and ethanol solutions for 15 minutes in each solvent, and then dried with nitrogen. The cleaned conductive substrate was then treated under ultraviolet ozone conditions for 20 minutes.

[0055] (2): The pretreated FTO was immersed in a 225 mmol / L TiCl4 aqueous solution and kept at 70 °C for 1 h to deposit a TiO2 electron transport layer. After deposition, the battery substrate was rinsed in deionized water and ethanol and sonicated for 3 min, then dried with nitrogen and annealed in air at 200 °C for 30 min to obtain an electron transport layer with a thickness of 20 nm.

[0056] (3): The preparation method of FAPbI3 single crystal is as follows: 1.5 mol lead acetate and 2 mol formamidine acetate are mixed and added to 5 ml of 57 w% hydroiodic acid aqueous solution. The mixture is kept at 80°C for 3 hours to obtain black FAPbI3. FAPbI3 single crystal is obtained by cleaning and annealing. The annealing temperature is 150°C and the treatment time is 18 h.

[0057] FAPbI3 single crystals, MACl, and sulfonamide were dissolved in a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide in a molar ratio of 1:0.35:0.04 (N,N-dimethylformamide and dimethyl sulfoxide volume ratio of 4:1), with a FAPbI3 concentration of 1.8 mol / L. The mixture was stirred at 40°C for 4 hours. Under a nitrogen atmosphere, 70 μL of the prepared precursor solution was pipetted and uniformly spin-coated onto the electron transport layer prepared in step (2) using a spin coater. The specific spin-coating process parameters were as follows: 6000 rpm for 50 seconds, and 800 μL of diethyl ether antisolvent was added dropwise 10 seconds after the start of spin-coating. After spin-coating, the film was annealed at 150°C for 10 minutes under a nitrogen atmosphere to obtain a perovskite film with an intrinsically dipole orientation and a thickness of 560 nm.

[0058] (4) 90 mg Spiro-OMeTAD, 39 μL 4-tert-butylpyridine, 23 μL bis(trifluoromethane)sulfonylimide lithium salt acetonitrile solution (mass concentration 520 mg / mL), 10 μL FK209 acetonitrile solution (mass concentration 375 mg / mL), and 1 mL chlorobenzene solution were mixed and stirred at room temperature for 12 h to obtain a doped Spiro-OMeTAD solution. The doped Spiro-OMeTAD solution was spin-coated onto the surface of an intrinsically dipole-oriented perovskite thin film, and dried to obtain a hole transport layer. The spin-coating speed was 3500 rpm, the spin-coating time was 25 seconds, and the thickness of the prepared hole transport layer (Spiro) was 200 nm.

[0059] (5) By means of thermal evaporation, in a vacuum degree less than 1*10 -4 Pa below, with The evaporation rate allows for the deposition of a 120 nm thick silver electrode layer on the hole transport layer, resulting in an organic-inorganic perovskite solar cell with oriented perovskite intrinsic dipoles.

[0060] The scanning electron microscope (SEM) image of the intrinsically dipole-oriented perovskite thin film prepared in step (3) of this embodiment is shown below. Figure 1 As shown in c. From Figure 1 It can be seen that the organic-inorganic perovskite with added sulfonamide exhibits a uniform morphology and shows an increased grain size compared to the comparative example.

[0061] The piezoelectric microscopy (PFM) phase diagram of the perovskite thin film with intrinsically dipole orientation prepared in step (3) of this embodiment is shown below. Figure 2 As shown in b. From Figure 2 The phase distribution shows that, compared with the single phase normal distribution of the comparative example, the internal region of the organic-inorganic perovskite with added sulfonamide exhibits additional vertical polarization.

[0062] The ultraviolet photoelectron spectroscopy (UPS) spectrum of the perovskite thin film with intrinsically dipole orientation prepared in step (3) of this embodiment is shown below. Figure 3 As shown in b, the work function of the perovskite film gradually decreases with increasing depth, i.e., closer to the electron transport layer. The perovskite film with intrinsically dipole orientation transitions from a p-type semiconductor to a more n-type semiconductor, exhibiting a gradient band structure, while the perovskite film prepared in Comparative Example 1 shows a similar band structure at different depths.

[0063] The structure and current density-voltage curve of the solar cell prepared in this embodiment are as follows: Figure 4 As shown, under standard test conditions (AM1.5 illumination), the reverse scanning photoelectric conversion efficiency of the battery device with oriented dipole arrangement is 23.84%, the open-circuit voltage is 1.143V, and the short-circuit current is 25.39mA / cm². 2 The fill factor is 82.15%; the photoelectric conversion efficiency under forward scanning is 23.43%, the open-circuit voltage is 1.142V, and the short-circuit current is 25.28mA / cm. 2 The fill factor was 81.15%, which is significantly higher than that of control sample 1.

[0064] The stability test of the unencapsulated solar cell device prepared in this embodiment is as follows: Figure 5 As shown, after 1080 hours of storage at 25°C, 20% relative humidity, in air, and in darkness, it can maintain more than 92% of the initial efficiency, which is a significant improvement over Comparative Example 1.

[0065] Example 2

[0066] A method for preparing an organic-inorganic perovskite solar cell with intrinsically aligned dipoles is described in Example 1, except that step (2) is omitted, i.e., the perovskite thin film with intrinsically aligned dipoles is directly deposited on a pretreated FTO transparent conductive substrate.

[0067] The other steps and conditions are the same as in Example 1.

[0068] The structure and current density-voltage curve of the solar cell prepared in this embodiment are as follows: Figure 6As shown, under standard test conditions (AM1.5 illumination), the reverse scanning photoelectric conversion efficiency of the battery device with oriented dipole arrangement is 20.37%, the open-circuit voltage is 1.063V, and the short-circuit current is 24.58mA / cm². 2 The fill factor is 77.95%, the photoelectric conversion efficiency under forward scanning is 19.56%, the open-circuit voltage is 1.054V, and the short-circuit current is 24.36mA / cm. 2 With a fill factor of 76.18%, it is one of the most efficient perovskite solar cells reported to date without an electron transport layer.

[0069] The stability test of the unencapsulated solar cell device prepared in this embodiment is as follows: Figure 7 As shown, after 1080 hours of storage at 25°C, 20% relative humidity, in air, and in darkness, it can maintain more than 90% of its initial efficiency, which is significantly improved compared to the device stability in Comparative Example 2.

[0070] Note: The perovskite thin film prepared in this embodiment is the same as that in Example 1. The polarization and band structure of the thin film are the same as those in Example 1, and will not be repeated here.

[0071] Example 3

[0072] A method for fabricating an organic-inorganic perovskite solar cell with intrinsically aligned perovskite dipoles, as described in Example 1, except that:

[0073] In step (3), FAPbI3 single crystals, MACl, and sulfonamide were dissolved in a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide at a molar ratio of 1:0.35:0.02 (N,N-dimethylformamide and dimethyl sulfoxide volume ratio of 4:1), with the concentration of FAPbI3 being 1.8 mol / L. The mixture was stirred at 40°C for 4 hours. Under a nitrogen atmosphere, 70 μL of the prepared precursor solution was transferred using a pipette and uniformly spin-coated onto the electron transport layer prepared in step (2) using a spin coater. The specific spin-coating process parameters were as follows: 6000 rpm for 50 seconds, and 800 μL of diethyl ether antisolvent was added dropwise 10 seconds after the start of spin-coating. After spin-coating, the film was annealed at 150°C for 10 minutes under a nitrogen atmosphere to obtain a perovskite film with intrinsically dipole orientation.

[0074] The other steps and conditions are the same as in Example 1.

[0075] The scanning electron microscope (SEM) image of the dipole-oriented perovskite layer prepared in step (3) of this embodiment is shown below. Figure 1 As shown in b. From Figure 1 It can be seen that the organic-inorganic perovskite with added sulfonamide exhibits a uniform morphology and shows a slightly increased grain size compared to the comparative example.

[0076] The solar cell prepared in this embodiment, under standard test conditions (AM1.5 illumination), exhibits a photoelectric conversion efficiency of 23.36% with reverse scanning, an open-circuit voltage of 1.129V, and a short-circuit current of 25.27mA / cm². 2 The fill factor is 81.87%; the photoelectric conversion efficiency under forward scanning is 22.65%, the open-circuit voltage is 1.121V, and the short-circuit current is 25.19mA / cm. 2 The fill factor was 80.22%. The photoelectric conversion efficiency was higher than that of Comparative Example 1, but slightly lower than that of Example 1.

[0077] Example 4

[0078] A method for fabricating an organic-inorganic perovskite solar cell with intrinsically aligned perovskite dipoles, as described in Example 1, except that:

[0079] In step (3), FAPbI3 single crystals, MACl, and sulfonamide were dissolved in a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide at a molar ratio of 1:0.35:0.08 (N,N-dimethylformamide and dimethyl sulfoxide volume ratio of 4:1), with the concentration of FAPbI3 being 1.8 mol / L. The mixture was stirred at 40°C for 4 hours. Under a nitrogen atmosphere, 70 μL of the prepared precursor solution was transferred using a pipette and uniformly spin-coated onto the electron transport layer prepared in step (2) using a spin coater. The specific spin-coating process parameters were as follows: 6000 rpm for 50 seconds, and 800 μL of diethyl ether antisolvent was added dropwise 10 seconds after the start of spin-coating. After spin-coating, the film was annealed at 150°C for 10 minutes under a nitrogen atmosphere to obtain a perovskite film with intrinsically dipole orientation.

[0080] The other steps and conditions are the same as in Example 1.

[0081] The scanning electron microscope (SEM) image of the dipole-oriented perovskite layer prepared in step (3) of this embodiment is shown below. Figure 1 As shown in d. Figure 1 It can be seen that the organic-inorganic perovskite with added sulfonamide exhibits a uniform morphology and shows a significantly increased grain size compared to the control.

[0082] The solar cell prepared in this embodiment, under standard test conditions (AM1.5 illumination), exhibits a photoelectric conversion efficiency of 22.95% with reverse scanning, an open-circuit voltage of 1.121V, and a short-circuit current of 25.15mA / cm². 2 The fill factor is 81.42%; the photoelectric conversion efficiency under forward scanning is 22.18%, the open-circuit voltage is 1.115V, and the short-circuit current is 25.01mA / cm. 2The fill factor was 79.55%. The photoelectric conversion efficiency was higher than that of Comparative Example 1, but slightly lower than that of Examples 1 and 3.

[0083] Example 5

[0084] A method for fabricating an organic-inorganic perovskite solar cell with intrinsically aligned perovskite dipoles, as described in Example 2, differs in that:

[0085] In step (3), FAPbI3 single crystal, MACl, and sulfonamide were dissolved in a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide at a molar ratio of 1:0.35:0.02 (N,N-dimethylformamide and dimethyl sulfoxide volume ratio of 4:1), with the concentration of FAPbI3 being 1.8 mol / L. The mixture was stirred at 40°C for 4 hours. Under a nitrogen-protected atmosphere, 70 μL of the prepared precursor solution was transferred using a pipette and uniformly spin-coated onto the FTO transparent conductive substrate pretreated in step (1). The specific spin-coating process parameters were as follows: 6000 rpm for 50 seconds, with 800 μL of diethyl ether antisolvent added 10 seconds after the start of spin-coating. After spin-coating, the film was annealed at 150°C for 10 minutes under a nitrogen atmosphere to obtain a perovskite film with intrinsically dipole orientation.

[0086] The other steps and conditions are the same as in Example 2.

[0087] The solar cells fabricated in this experiment, under standard test conditions (AM1.5 illumination), exhibited a reverse-scan photoelectric conversion efficiency of 19.61%, an open-circuit voltage of 1.043V, and a short-circuit current of 24.44mA / cm². 2 The fill factor is 76.92%; the photoelectric conversion efficiency under forward scanning is 18.89%, the open-circuit voltage is 1.035V, and the short-circuit current is 24.21mA / cm. 2 The fill factor was 75.37%. The photoelectric conversion efficiency was higher than that of Comparative Example 2, but slightly lower than that of Example 2.

[0088] Example 6

[0089] A method for fabricating an organic-inorganic perovskite solar cell with intrinsically aligned perovskite dipoles, as described in Example 2, differs in that:

[0090] In step (3), FAPbI3 single crystal, MACl, and sulfonamide were dissolved in a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide at a molar ratio of 1:0.35:0.08 (N,N-dimethylformamide and dimethyl sulfoxide volume ratio of 4:1), with the concentration of FAPbI3 being 1.8 mol / L. The mixture was stirred at 40°C for 4 hours. Under a nitrogen-protected atmosphere, 70 μL of the prepared precursor solution was transferred using a pipette and uniformly spin-coated onto the FTO transparent conductive substrate pretreated in step (1). The specific spin-coating process parameters were as follows: rotation speed 6000 rpm, running for 50 seconds, and 800 μL of diethyl ether antisolvent added 10 seconds after the start of spin-coating. After spin-coating, the film was annealed at 150°C for 10 minutes in a nitrogen atmosphere to obtain a perovskite film with intrinsically dipole orientation.

[0091] The other steps and conditions are the same as in Example 2.

[0092] The solar cell prepared in this embodiment, under standard test conditions (AM1.5 illumination), exhibits a photoelectric conversion efficiency of 18.99% with reverse scanning, an open-circuit voltage of 1.045V, and a short-circuit current of 24.05mA / cm². 2 The fill factor is 75.58%; the photoelectric conversion efficiency under forward scanning is 18.29%, the open-circuit voltage is 1.032V, and the short-circuit current is 23.88mA / cm. 2 The fill factor was 74.23%. The photoelectric conversion efficiency was higher than that of Comparative Example 2, but slightly lower than that of Examples 2 and 5, while the hysteresis phenomenon was slightly improved compared to Example 5.

[0093] Example 7

[0094] A method for fabricating an organic-inorganic perovskite solar cell with intrinsically aligned perovskite dipoles, as described in Example 1, except that:

[0095] In step (3), the film annealing temperature was changed. FAPbI3 single crystals, MACl, and sulfonamide were dissolved in a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide at a molar ratio of 1:0.35:0.04 (N,N-dimethylformamide and dimethyl sulfoxide volume ratio 4:1), with a FAPbI3 concentration of 1.8 mol / L. The mixture was stirred at 40°C for 4 hours. Under a nitrogen atmosphere, 70 μL of the prepared precursor solution was transferred using a pipette and uniformly spin-coated onto the electron transport layer prepared in step (2) using a spin coater. The specific spin-coating process parameters were as follows: 6000 rpm for 50 seconds, with 800 μL of diethyl ether antisolvent added 10 seconds after the start of spin-coating. After spin-coating, the film was annealed at 100°C for 15 minutes under a nitrogen atmosphere to obtain a perovskite film with intrinsically dipole orientation.

[0096] The other steps and conditions are the same as in Example 1.

[0097] The solar cell prepared in this embodiment, under standard test conditions (AM1.5 illumination), exhibits a photoelectric conversion efficiency of 23.34% with reverse scanning, an open-circuit voltage of 1.131V, and a short-circuit current of 25.26mA / cm². 2 The fill factor is 81.72%; the photoelectric conversion efficiency under forward scanning is 22.81%, the open-circuit voltage is 1.128V, and the short-circuit current is 25.11mA / cm. 2 The fill factor was 80.52%. The photoelectric conversion efficiency was higher than that of Comparative Example 1, but slightly lower than that of Example 1.

[0098] Example 8

[0099] A method for fabricating an organic-inorganic perovskite solar cell with intrinsically aligned perovskite dipoles, as described in Example 2, differs in that:

[0100] In step (3), the film annealing temperature was changed. FAPbI3 single crystal, MACl, and sulfonamide were dissolved in a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide in a molar ratio of 1:0.35:0.04 (N,N-dimethylformamide and dimethyl sulfoxide volume ratio of 4:1), wherein the concentration of FAPbI3 was 1.8 mol / L, and stirred at 40°C for 4 hours. Under a nitrogen-protected atmosphere, 70 μL of the prepared precursor solution was transferred using a pipette and uniformly spin-coated onto the FTO transparent conductive substrate pretreated in step (1) using a spin coater. The specific spin-coating process parameters were as follows: rotation speed 6000 rpm, running for 50 seconds, and 800 μL of diethyl ether antisolvent was added dropwise 10 seconds after the start of spin-coating. After spin-coating, the film was annealed at 100°C for 15 minutes in a nitrogen atmosphere to prepare a perovskite film with intrinsically dipole orientation.

[0101] The other steps and conditions are the same as in Example 2.

[0102] The solar cell prepared in this embodiment, under standard test conditions (AM1.5 illumination), exhibits a photoelectric conversion efficiency of 19.74% with reverse scanning, an open-circuit voltage of 1.058V, and a short-circuit current of 24.34mA / cm². 2 The fill factor is 76.67%; the photoelectric conversion efficiency under forward scanning is 18.98%, the open-circuit voltage is 1.047V, and the short-circuit current is 24.13mA / cm. 2 The fill factor was 75.12%. The photoelectric conversion efficiency was higher than that of Comparative Example 2, but slightly lower than that of Example 2.

[0103] Therefore, the annealing temperature of the perovskite film is a crucial factor determining the evaporation rate of sulfonamide. A higher annealing temperature enhances the reactivity of carrier redirection and facilitates the directional alignment of dipoles. However, excessively high annealing temperatures are detrimental to the stability of organic components in the perovskite film. The preferred annealing parameters for this invention are annealing at 150°C for 10 minutes.

[0104] Comparative Example 1

[0105] An organic-inorganic perovskite solar cell fabrication method, as described in Example 1, except that:

[0106] In step (3), sulfonamide is not added. Specifically, FAPbI3 single crystals and MACl are dissolved in a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide at a molar ratio of 1:0.35 (N,N-dimethylformamide and dimethyl sulfoxide volume ratio is 4:1), with a FAPbI3 concentration of 1.8 mol / L. The mixture is stirred at 40°C for 4 hours. Under a nitrogen atmosphere, 70 μL of the prepared precursor solution is transferred using a pipette and uniformly spin-coated onto the electron transport layer prepared in step (2). The specific spin-coating parameters are as follows: rotation speed 6000 rpm, running for 50 seconds, and 800 μL of diethyl ether antisolvent added 10 seconds after the start of spin-coating. After spin-coating, the film is annealed at 150°C for 10 minutes under a nitrogen atmosphere to obtain a perovskite film.

[0107] The other steps and conditions are the same as in Example 1.

[0108] The scanning electron microscope (SEM) image of the perovskite layer prepared in step (3) of this comparative example is shown below. Figure 1 As shown in a. From Figure 1 It can be seen that organic-inorganic perovskite without the addition of sulfonamide has smaller and less uniform grain size.

[0109] The phase image of the perovskite layer prepared in step (3) of this comparative example is shown in the piezoelectric microscopy (PFM) phase image. Figure 2 As shown in a. From Figure 2 The phase distribution shows that the phase of the thin film is normally distributed at 127°.

[0110] The ultraviolet photoelectron spectroscopy (UPS) spectrum of the perovskite layer prepared in step (3) of this comparative example is shown below. Figure 3 As shown in figure a, the surface work function and band edge position of the thin film remain essentially unchanged with increasing depth, exhibiting a flat band structure.

[0111] The solar cell prepared in this comparative example, under standard test conditions (AM1.5 illumination), exhibited a reverse scanning photoelectric conversion efficiency of 21.61%, an open-circuit voltage of 1.091V, and a short-circuit current of 24.98mA / cm². 2The fill factor is 79.28%, the photoelectric conversion efficiency under forward scanning is 20.83%, the open-circuit voltage is 1.086V, and the short-circuit current is 24.76mA / cm. 2 The fill factor is 77.47%.

[0112] The stability test results of the unencapsulated solar cell device prepared in this comparative example are as follows: Figure 5 As shown, after 1080 hours of storage at 25°C, 20% relative humidity, in air, and in darkness, only 79% of the initial efficiency is retained.

[0113] Comparative Example 2

[0114] An organic-inorganic perovskite solar cell fabrication method, as described in Example 2, except that:

[0115] In step (3), sulfonamide is not added. Specifically, FAPbI3 single crystals and MACl are dissolved in a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide at a molar ratio of 1:0.35 (N,N-dimethylformamide and dimethyl sulfoxide volume ratio is 4:1), with a FAPbI3 concentration of 1.8 mol / L. The mixture is stirred at 40°C for 4 hours. Under a nitrogen atmosphere, 70 μL of the prepared precursor solution is transferred using a pipette and uniformly spin-coated onto the conductive substrate treated in step (1). The specific spin-coating parameters are as follows: rotation speed 6000 rpm, running for 50 seconds, and 800 μL of diethyl ether antisolvent added 10 seconds after the start of spin-coating. After spin-coating, the film is annealed at 150°C for 10 minutes under a nitrogen atmosphere to obtain a perovskite film.

[0116] The other steps and conditions are the same as in Example 2.

[0117] The solar cell prepared in this comparative example, under standard test conditions (AM1.5 illumination), exhibited a reverse scanning photoelectric conversion efficiency of 16.00%, an open-circuit voltage of 0.971V, and a short-circuit current of 23.85mA / cm². 2 The fill factor is 69.07%, the photoelectric conversion efficiency under forward scanning is 12.61%, the open-circuit voltage is 0.923V, and the short-circuit current is 23.41mA / cm. 2 The fill factor was 58.34%. The photoelectric conversion efficiency was significantly lower than that of Example 2, and it exhibited severe hysteresis.

[0118] The stability test results of the unencapsulated solar cell device prepared in this comparative example are as follows: Figure 7 As shown, after 1080 hours of storage at 25°C, 20% relative humidity, in air, and in darkness, only 64% of the initial efficiency was maintained, indicating a significant loss of efficiency.

[0119] Comparative Example 3

[0120] An organic-inorganic perovskite solar cell fabrication method, as described in Example 1, except that:

[0121] In step (3), a sulfonamide analog is introduced: FAPbI3 single crystal, MACl, and 3,4-difluorobenzenesulfonamide are dissolved in a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide in a molar ratio of 1:0.35:0.04 (N,N-dimethylformamide and dimethyl sulfoxide volume ratio is 4:1), wherein the concentration of FAPbI3 is 1.8 mol / L, and the mixture is stirred at 40°C for 4 hours. Under a nitrogen-protected atmosphere, 70 μL of the prepared precursor solution is transferred using a pipette and uniformly spin-coated onto the electron transport layer prepared in step (2) using a spin coater. The specific spin-coating process parameters are as follows: rotation speed 6000 rpm, running for 50 seconds, and 800 μL of diethyl ether antisolvent is added dropwise 10 seconds after the start of spin-coating. After spin-coating, the film is annealed at 150°C for 10 minutes in a nitrogen atmosphere to obtain a perovskite film.

[0122] The 3,4-difluorobenzenesulfonamide used in step (3) has similar functional groups to the sulfonamides preferred in this invention, and is used as a reference in this comparative example to study the effect of sulfonamide analogs on perovskite solar cells.

[0123] The other steps and conditions are the same as in Example 1.

[0124] The solar cell prepared in this comparative example, under standard test conditions (AM1.5 illumination), exhibited a photoelectric conversion efficiency of 22.97% with reverse scanning, an open-circuit voltage of 1.126V, and a short-circuit current of 25.11mA / cm². 2 The fill factor is 81.26%, the photoelectric conversion efficiency under forward scanning is 12.61%, the open-circuit voltage is 1.120V, and the short-circuit current is 25.02mA / cm. 2 The fill factor is 22.09%. The photoelectric conversion efficiency is lower than that of the battery in Example 1, and it exhibits a significant hysteresis phenomenon compared to Example 1.

[0125] Comparative Example 4

[0126] An organic-inorganic perovskite solar cell fabrication method, as described in Example 2, except that:

[0127] In step (3), a sulfonamide analog is introduced: FAPbI3 single crystal, MACl, and 3,4-difluorobenzenesulfonamide are dissolved in a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide in a molar ratio of 1:0.35:0.04 (N,N-dimethylformamide and dimethyl sulfoxide volume ratio is 4:1), wherein the concentration of FAPbI3 is 1.8 mol / L, and the mixture is stirred at 40°C for 4 hours. Under a nitrogen-protected atmosphere, 70 μL of the prepared precursor solution is transferred using a pipette and uniformly spin-coated onto the FTO transparent conductive substrate pretreated in step (1) using a spin coater. The specific spin-coating process parameters are as follows: rotation speed 6000 rpm, running for 50 seconds, and 800 μL of diethyl ether antisolvent is added dropwise 10 seconds after the start of spin-coating. After spin-coating, the film is annealed at 150°C for 10 minutes in a nitrogen atmosphere to obtain a perovskite film.

[0128] The 3,4-difluorobenzenesulfonamide used in step (3) has similar functional groups to the sulfonamides preferred in this invention, and is used as a reference in this comparative example to study the effect of sulfonamide analogs on perovskite solar cells.

[0129] The other steps and conditions are the same as in Example 2.

[0130] The solar cell prepared in this comparative example, under standard test conditions (AM1.5 illumination), exhibited a reverse scanning photoelectric conversion efficiency of 17.93%, an open-circuit voltage of 1.013V, and a short-circuit current of 24.55mA / cm². 2 The fill factor is 72.10%, the photoelectric conversion efficiency under forward scanning is 14.75%, the open-circuit voltage is 0.957V, and the short-circuit current is 23.96mA / cm. 2 The fill factor is 64.33%. The photoelectric conversion efficiency is lower than that of the battery in Example 2, and it exhibits severe hysteresis.

[0131] Therefore, the performance improvement of 3,4-difluorobenzenesulfonamide as an additive in perovskite films is due to the interaction between functional groups such as S=O and perovskite Pb. + The coordination between the components passivates defects and has little effect on the band structure of perovskite thin films. The energy level mismatch is not optimized, resulting in low photoelectric conversion efficiency of devices without electron transport layer structure. Inefficient carrier transport leads to a relatively serious hysteresis phenomenon.

Claims

1. An organic-inorganic perovskite solar cell with oriented perovskite intrinsic dipoles, characterized in that, It includes, from bottom to top, a conductive substrate, an electron transport layer, a perovskite thin film with intrinsically aligned dipoles, a hole transport layer, and a metal counter electrode. or, It includes a conductive substrate arranged from bottom to top, a perovskite thin film with intrinsic dipoles oriented, a hole transport layer, and a metal counter electrode; The method for preparing the intrinsically dipole-oriented perovskite thin film includes the following steps: adding sulfonamide to a perovskite precursor solution and mixing it evenly to obtain a spin-coating solution; spin-coating the solution onto an electron transport layer or a conductive substrate and annealing it to obtain the intrinsically dipole-oriented perovskite thin film. The preparation of the perovskite precursor solution includes the following steps: dissolving formamidine lead iodine (FAPbI3) single crystal powder and methylamine chloride (MACl) in a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide to obtain the perovskite precursor solution. The annealing temperature is 100-160℃.

2. The organic-inorganic perovskite solar cell with oriented perovskite intrinsic dipoles according to claim 1, characterized in that, Includes one or more of the following conditions: i. The conductive substrate is a fluorine-doped tin oxide (FTO) transparent conductive substrate with a thickness of 140-160 nm; ii. The electron transport layer is made of dense titanium dioxide with a thickness of 20-30 nm; iii. The hole transport layer is 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene (Spiro-OMeTAD), with a thickness of 200-250 nm; iv. The metal counter electrode layer is a silver (Ag) counter electrode with a thickness of 100-140 nm.

3. The organic-inorganic perovskite solar cell with oriented perovskite intrinsic dipoles according to claim 1, characterized in that, The thickness of the intrinsic dipole-oriented perovskite film is 550-600 nm; the intrinsic dipole-oriented perovskite film has a gradient band structure, which transitions from p-type semiconductor to n-type semiconductor from bottom to top.

4. The organic-inorganic perovskite solar cell with oriented perovskite intrinsic dipoles according to claim 1, characterized in that, The molar ratio of formamidinium lead-iodine single crystal powder to methylamine chloride is 1:0.35; the volume ratio of N,N-dimethylformamide to dimethyl sulfoxide in the mixed solvent is 3-5:1; and the concentration of formamidinium lead-iodine single crystal powder in the mixed solvent is 1.6-1.8 mol / L.

5. The organic-inorganic perovskite solar cell with oriented perovskite intrinsic dipoles according to claim 4, characterized in that, The preparation method of formamidine lead-iodine single crystal powder includes the following steps: mixing lead acetate and formamidine acetate in a molar ratio of 3:4, adding them to a hydroiodic acid aqueous solution, keeping the mixture at 80-90℃ for 2-4 hours, washing, and undergoing a second annealing treatment to obtain formamidine lead-iodine single crystal powder; the concentration of the hydroiodic acid aqueous solution is 55-58 wt%; the second annealing treatment temperature is 150-180℃, and the treatment time is 12-24 hours.

6. The organic-inorganic perovskite solar cell with oriented perovskite intrinsic dipoles according to claim 1, characterized in that, The molar ratio of formamidinium, lead, and iodine in the sulfonamide and perovskite precursor solution is 0.02-0.08:

1.

7. The organic-inorganic perovskite solar cell with oriented perovskite intrinsic dipoles according to claim 1, characterized in that, The spin coating parameters are: rotation speed 5000-6000 rpm, spin coating time 40-50 seconds, and diethyl ether anti-solvent added dropwise 10 seconds after the start of spin coating. The volume ratio of diethyl ether to spin coating solution is 10-13:

1.

8. The organic-inorganic perovskite solar cell with oriented perovskite intrinsic dipoles according to claim 1, characterized in that, The annealing process takes 10-15 minutes.

9. The organic-inorganic perovskite solar cell with oriented perovskite intrinsic dipoles according to claim 1, characterized in that, The annealing temperature is 140-160℃.

10. The organic-inorganic perovskite solar cell with oriented perovskite intrinsic dipoles according to claim 1, characterized in that, Both spin coating and annealing processes must be carried out in a protective gas atmosphere; the protective gas is nitrogen.

11. A method for preparing an organic-inorganic perovskite solar cell with oriented perovskite intrinsic dipoles as described in any one of claims 1-10, comprising the steps of: (1) Pretreatment of conductive substrate; (2) An electron transport layer is prepared on a conductive substrate, and then an intrinsic dipole-oriented perovskite thin film is prepared on the electron transport layer; or, an intrinsic dipole-oriented perovskite thin film is prepared directly on a conductive substrate. (3) A hole transport layer is prepared on a perovskite thin film with intrinsic dipoles oriented in a specific direction; (4) Prepare a metal counter electrode on the hole transport layer.

12. The method for preparing an organic-inorganic perovskite solar cell with oriented perovskite intrinsic dipoles according to claim 11, characterized in that, Includes one or more of the following conditions: i. In step (1), the pretreatment method of the conductive substrate includes the following steps: ultrasonically cleaning the conductive substrate in deionized water, isopropanol and ethanol in sequence, and drying it with nitrogen gas. Then, ultraviolet ozone treatment is performed; the ultrasonic cleaning time in each solvent is 10-20 minutes; the ultraviolet ozone treatment time is 10-30 minutes. ii. In step (2), the method for preparing an electron transport layer on a conductive substrate includes the following steps: immersing the conductive substrate in an aqueous solution of titanium tetrachloride (TiCl4), and then washing, drying, and annealing at high temperature to obtain the electron transport layer; The concentration of the TiCl4 aqueous solution was 200-250 mmol / L; the immersion temperature was 65-75℃ and the immersion time was 55-65 min; the high-temperature annealing temperature was 180-200℃ and the treatment time was 30-60 min, and the treatment atmosphere was air. iii. In step (3), the method for preparing the hole transport layer includes the following steps: mixing Spiro-OMeTAD, chlorobenzene, 4-tert-butylpyridine, lithium bis(trifluoromethane)sulfonylimide salt acetonitrile solution, and FK209 ([4-tert-butyl-2-(1H- A solution of pyrazol-1-ylpyridine, cobalt(III) and acetonitrile was mixed and stirred thoroughly to dissolve the doped Spiro-OMeTAD solution. The doped Spiro-OMeTAD solution was then spin-coated onto an intrinsically dipole-oriented perovskite film, followed by drying to obtain a hole transport layer. The mass ratio of Spiro-OMeTAD to chlorobenzene was 90:1 mg / mL, the concentration of the lithium bis(trifluoromethane)sulfonylimide acetonitrile solution was 500-540 mg / mL, the concentration of the FK209 acetonitrile solution was 350-400 mg / mL, and the volume ratio of chlorobenzene, 4-tert-butylpyridine, the lithium bis(trifluoromethane)sulfonylimide acetonitrile solution, and the FK209 acetonitrile solution was 1000:39:23:

10. The spin-coating speed was 3000-4000 rpm, and the spin-coating time was 20-30 seconds. iv. By means of thermal evaporation deposition, under a vacuum degree of less than 1*10 -4 At Pa, metal counter electrodes were deposited on the hole transport layer at an evaporation rate of 0.1–0.8 Å / s.

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