A normal perovskite solar cell based on modification of buried interface by dipole molecules and a preparation method thereof

Abstract

The application discloses a normal perovskite solar cell based on modification of buried bottom interface by dipole molecules and a preparation method thereof, and belongs to the technical field of perovskite solar cells. The application adopts dipole molecules containing phosphate groups and carbonyl functional groups to modify the SnO2 / perovskite buried bottom interface. The dipole molecules can effectively passivate interface defects, release interface residual stress and promote improvement of perovskite film quality, so that the device efficiency and long-term operation stability are improved. The method adopted by the application aims to passivate interface defects and promote directional electron transmission and extraction by multiple functional groups of the dipole molecules, so as to reduce interface energy loss and improve interface stability, thereby providing a new idea for realizing high-efficiency, long-term operation stable perovskite solar cells and laying a solid foundation for commercial application of perovskite photovoltaic technology.

Description

Technical Field

[0001] This invention belongs to the field of perovskite solar cell technology, and provides an upright perovskite solar cell based on a buried interface modified with dipole molecules and its preparation method. Background Technology

[0002] Over the past decade, metal halide perovskite solar cells (PSCs) have garnered significant attention due to their superior photoelectric performance. In particular, the power conversion efficiency (PCE) of PSCs has now exceeded 27%, comparable to silicon solar cells. However, most high-efficiency PSCs are fabricated in inert gas environments such as nitrogen, leading to high fabrication costs, poor reproducibility, and incompatibility with large-scale fabrication processes. To effectively overcome these limitations, air-processed PSCs have attracted considerable attention, achieving significant progress in PCE and stability in recent years. Specifically, the PCE of air-processed nip-type upright PSCs has now exceeded 26%, but this still lags behind the high-efficiency PSCs fabricated under inert gas atmospheres and is far below the Shockley-Queisser theoretical efficiency limit of 33%. Therefore, air-processed nip-type PSCs still face numerous technical challenges. It is well known that the interface between the SnO2 electron transport layer (ETL) and the perovskite layer (called the buried interface) is crucial for achieving high-efficiency and stable upright PSCs. However, defects, residual stress, and energy level mismatches often exist at the SnO2 / perovskite interface, leading to severe nonradiative recombination, which limits the photovoltaic performance of upright PSCs and restricts their long-term stability. Therefore, it is urgent to improve the PCE and stability of upright PSCs by precisely controlling the buried interface from the perspective of function-driven molecular design.

[0003] Among various interface modification materials, interface dipole molecules (IDMs) have significant advantages in modifying buried interfaces of PSCs, specifically: First, IDMs easily tune the work function of SnO2 and perovskite, promoting energy level matching at the SnO2 / perovskite interface and thus suppressing interfacial charge accumulation; second, the intrinsic dipole moment of these molecules can enhance the interfacial electric field, promoting directional carrier transport and reducing nonradiative recombination losses; furthermore, the functional groups containing lone pairs of electrons on IDMs can coordinate with undercoordinated metal ion defects in the films on both sides of the interface, reducing defect-induced nonradiative recombination. Although IDMs have made a series of breakthroughs in interfacial defect passivation research, there are still many opportunities in screening novel IDMs. Functional group design is crucial to simultaneously achieve energy level tuning and defect passivation. Considering undercoordinated metal ions (such as Pb...) 2+ and Sn 4+The main defect at the buried interface is the presence of functional groups with strong coordination capabilities, such as -COOH, C=O, -SH, and -PO3H, which should be introduced to functionalize IDMs. To maximize the defect passivation effect of IDMs and enhance their interaction with the functional layer, it is necessary to design IDMs with multiple active sites to modulate the buried interface. Furthermore, dipole moment modulation is essential for improving carrier transport capacity at the interface. Therefore, when designing IDMs, both defect passivation and interfacial dipole effects should be considered to effectively suppress nonradiative recombination losses caused by defects and promote interfacial charge transport.

[0004] In summary, there is an urgent need to design and develop multifunctional IDMs through functional groups to regulate the buried interface and further improve the PCE and stability of air-prepared upright PSCs. Summary of the Invention

[0005] In view of this, one objective of the present invention is to provide an upright perovskite solar cell based on a buried interface modified by dipole molecules; another objective of the present invention is to provide a method for preparing an upright perovskite solar cell based on a buried interface modified by dipole molecules.

[0006] To achieve the above objectives, the present invention provides the following technical solution: 1. A positive perovskite solar cell based on a dipole molecule-modified buried interface, wherein the positive perovskite solar cell has a dipole molecule-modified layer between the perovskite light-absorbing layer and the electron transport layer, with dipole molecules as the material.

[0007] Preferably, the dipolar molecule is any one of phthaloylglycine (DA), phthalimide (DD), and diethyl phthalimide methyl phosphate (DP), and its chemical structural formula is as follows: .

[0008] Preferably, the upright perovskite solar cell comprises, from bottom to top, a conductive substrate layer, an electron transport layer, a dipole molecule modification layer, a perovskite light-absorbing layer, a hole transport layer, and a metal back electrode.

[0009] More preferably, the conductive substrate is either ITO or FTO; The electron transport layer is made of any one or more of tin dioxide (SnO2), titanium dioxide (TiO2), or zinc oxide (ZnO); The perovskite light-absorbing layer is made of ABX3 type perovskite, where A is methylamine ion (MA). + ), formamidinium ion (FA) + ) or cesium ions (Cs +Any one or more of the following, where B is lead ion (Pb). 2+ ) or tin ions (Sn 2+ X is any one or more of the following, where X is an iodide ion (I - ), bromide ions (Br) - ) or chloride ions (Cl - Any one or more of the following; The hole transport layer is made of 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene (Spiro-OMeTAD), poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), poly(3-hexylthiophene-2,5-diyl) (P3HT), or nickel oxide (NiO). x Any one or more of the following; The material of the back electrode layer is any one of Au, Ag, or low-temperature carbon electrode.

[0010] 2. The above-mentioned method for preparing an upright perovskite solar cell includes the following steps: (1) The electron transport layer material solution was spin-coated onto a pretreated conductive substrate and then subjected to annealing and ultraviolet ozone irradiation treatment to prepare the electron transport layer. (2) Spin-coat the solution of the dipole molecules onto the electron transport layer prepared in step (1), and anneal the layer to obtain the dipole molecule modified layer. (3) The solution of the perovskite precursor material is dropped onto the dipole molecule modified layer prepared in step (2), and after spin coating, an antisolvent is added and then annealed to obtain the perovskite light-absorbing layer. (4) Spin-coat the hole transport layer material solution onto the perovskite light-absorbing layer prepared in step (3) to obtain the hole transport layer; (5) The metal back electrode material is deposited on the hole transport layer prepared in step (4) to obtain the upright perovskite solar cell based on the buried interface modified by dipole molecules.

[0011] Preferably, in step (1), the pretreatment method of the conductive substrate is as follows: the conductive substrate is cleaned and then subjected to ultraviolet ozone pretreatment or plasma pretreatment. The method of ultraviolet ozone pretreatment is as follows: the conductive substrate is ultrasonically cleaned sequentially with detergent, deionized water, and anhydrous ethanol, then dried with nitrogen gas, and treated with ultraviolet ozone for 10-50 min.

[0012] Preferably, in step (1), the spin coating speed is 1000~5000 rpm and the time is 20~60 s, and the annealing temperature is 80~150 ℃ and the time is 5~30 min; The ultraviolet ozone treatment time is 10~50 min.

[0013] Preferably, in step (2), the concentration of the dipole molecules in the solution is 0.1 to 10 mg / mL, and the solvent in the solution is any one or more of dichloromethane, chloroform, chlorobenzene, dichlorobenzene, toluene, ethyl acetate or isopropanol; The spin coating speed is 2000~6000 rpm and the time is 10~50 s, and the annealing temperature is 80~150℃ and the time is 10~50 min.

[0014] Preferably, in step (3), the antisolvent is any one or more of chlorobenzene, dichloromethane, toluene, ethyl acetate, chloroform or diethyl ether; The spin coating process is carried out in two steps: first, spin coating is performed at a speed of 1000-3000 rps for 10-60 s, and then spin coating is performed at a speed of 2000-6000 rps for 20-60 s. The annealing temperature is 100~150 ℃ and the annealing time is 20~50 min; Preferably, in step (4), the spin coating speed is 2000~6500 rpm and the time is 20~60 s.

[0015] The beneficial effects of this invention are: 1. This invention discloses a positive perovskite solar cell based on a buried interface modified with dipole molecules. By modifying the interface between the perovskite light-absorbing layer and the electron transport layer with dipole molecules, the interface defects are passivated, residual tensile stress at the interface is released, the interface energy level mismatch is reduced, and double-sided chemical bridging is achieved, thereby suppressing non-radiative recombination at the interface and significantly improving the stability of the buried interface.

[0016] 2. This invention discloses a perovskite solar cell based on a buried interface modified with dipole molecules that achieves a photoelectric conversion efficiency of 25.68%. The unencapsulated perovskite solar cell can still maintain an initial efficiency of over 93.9% after aging for 1944 hours under conditions of 20-30% relative humidity, demonstrating excellent environmental stability. The perovskite solar cell still retains over 90.8% of its initial efficiency after continuous operation at maximum power point for 782 hours.

[0017] 3. This invention uses dipole molecules as interface modification layer materials, which have the advantages of simple process, good reproducibility and good universality in improving upright perovskite solar cells. It is of great significance in promoting the industrialization of upright perovskite solar cells.

[0018] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0019] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein: Figure 1 In Figure a, the electrostatic potential distribution diagrams of the dipole molecules DA, DD, and DP used in Examples 1-3 are shown respectively; in Figure b, the optimal configurations and binding energies of DA, DD, and DP adsorbed on the SnO2 surface are shown respectively; and in Figures c and d, the optimal configurations and binding energies of DA, DD, and DP adsorbed on the perovskite surface are shown respectively. Figure 2 The images show the FTIR spectra of the DP and SnO2 / DP films in Example 1. Figure 3 In the figure, a and b are the Sn 3d and O1s XPS images of the SnO2 film in the comparative example and the SnO2 / DP film in Example 1, respectively. Figure 4 In the figures, a and b are the AFM images of the SnO2 film in the comparative example and the SnO2 / DP film in Example 1, respectively. Figure 5 In the figures, a and b are the KPFM diagrams of the SnO2 film in the comparative example and the SnO2 / DP film in Example 1, respectively. Figure 6 In the figure, a and b represent the conductivity and electron mobility of the SnO2 film in the comparative example and the SnO2 / DP film in Example 1, respectively. Figure 7 The FTIR spectra of DP, DP+PbI2 and DP+FAI in Example 1; Figure 8 In the comparison example, 'a' represents the FAI in the comparative example and the DP+FAI in Example 1. 1 H NMR spectra, b represents FAI in the comparative example and DP, DP+FAI and DP+PbI2 in Example 1. 13 C10 NMR spectra, where c represents DP, DP+FAI, and DP+PbI2 from Example 1. 31 P NMR spectrum; Figure 9In Figure a, Pb 4f XPS plots of the PVSK film in the comparative example and the DP / PVSK film in Example 1 are shown; in Figure b, N 1s XPS plots of the DP and DP / PVSK films in Example 1 are shown; and in Figure c, I 3d XPS plots of the PVSK film in the comparative example and the DP / PVSK film in Example 1 are shown. Figure 10 In Figure 1, a and b are the GIXRD patterns of the unmodified perovskite film (Control) prepared in the comparative example and the DP-modified perovskite film (DP) in Example 1, respectively. Figure 2 is the (211) crystal plane of the unmodified perovskite film (Control) prepared in the comparative example and the DP-modified perovskite film (DP) in Example 1. The function graph; Figure 11 In the figure, a and b are PL mapping diagrams of the perovskite film (Control) without dipole molecule modification prepared in the comparative example and the perovskite film (DP) modified with DP in Example 1, respectively. Figure 12 SCLC images of pure electronic devices (ITO / SnO2 (or SnO2 / DP) / PVSK / PCBM / BCP / Ag) prepared in the comparative examples of the unmodified perovskite film (Control) and the DP-modified perovskite film (DP) in Example 1. Figure 13 In the figures, a and b are SEM images of the surface of the perovskite film (Control) without dipole molecule modification prepared in the comparative example and the perovskite film (DP) modified with DP in Example 1, respectively; c and d are the corresponding grain size distribution statistics. Figure 14 In the figures, a and b are SEM images of the bottom surfaces of the perovskite film (Control) without dipole molecule modification prepared in the comparative example and the perovskite film (DP) modified with DP in Example 1, respectively; c and d are the corresponding grain size distribution statistics. Figure 15 In the comparative examples, a and b represent the SnO content in SnO2, respectively. x The unmodified perovskite film (Glass / ITO / SnO2 / PVSK) prepared on the substrate and the SnO2 film in Example 1 x PL and TRPL spectra of DP-modified perovskite films (Glass / ITO / SnO2 / DP / PVSK) prepared on DP substrates. Figure 16The current density-voltage curves are shown for the unmodified perovskite solar cell device (Control) in the comparative examples and the DP-modified perovskite solar cell device (DP) in Example 1. Figure 17 To compare the stability of the unmodified perovskite solar cell device (Control) in the comparative examples and the DP-modified perovskite solar cell device (DP) in Example 1 under an environment with a humidity of 20-30%; Figure 18 To compare the stability of the unmodified perovskite solar cell device (Control) in the examples and the DP-modified perovskite solar cell device (DP) in Example 1 under continuous maximum power point (MPP) tracking. Detailed Implementation

[0020] The present invention will be further described below with reference to specific embodiments. The accompanying drawings are for illustrative purposes only, representing schematic diagrams rather than actual physical objects, and should not be construed as limiting the scope of this patent. To better illustrate the embodiments of the present invention, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0021] The structural formulas of phthaloylglycine (DA), phthalimide (DD), and diethyl phthalimide methyl phosphate (DP) involved in the following examples are not shown below: .

[0022] Comparative Examples The specific method for fabricating upright perovskite solar cells without dipole molecule modification of the buried interface is as follows: (1) The ITO conductive substrate is ultrasonically cleaned with detergent, deionized water and anhydrous ethanol for 20 min in sequence, dried with nitrogen, treated with ultraviolet ozone for 15 min and cooled to obtain the pretreated ITO conductive substrate for use. (2) Add 200 μL of ammonia solution with a mass fraction of 28% and 200 μL of RbCl solution with a concentration of 3 mg / mL to 200 μL of SnO2 nanoparticle dispersion with a mass fraction of 12%. Mix well to obtain a SnO2 dispersion treated with ammonia and RbCl. Filter the dispersion through 0.22 μm PVDF. Take 40 μL and drop it onto the ITO conductive substrate pretreated in step (1). Spin coat at 3000 rpm for 30 s. Then anneal at 100 ℃ for 30 min. Finally, perform ultraviolet ozone treatment for 20 min to prepare the electron transport layer. (3) Dissolve 18.75 mg MABr, 6.15 mg PbBr2, 19.58 mg CsI, 33 mg MACl, 246.28 mg FAI and 764.45 mg PbI2 in 1 mL of a mixed solvent of DMF and DMSO (V DMF :V DMSO = 4:1), shake for 1 h to obtain a perovskite precursor solution with a concentration of 1.675 mol / L. Then, the perovskite precursor solution is filtered through 0.22 μm PTFE, and 40 μL is added to the electron transport layer prepared in step (2). First, spin coat at 1000 rpm for 10 s, then spin coat at 5000 rpm for 30 s. 80 μL of chlorobenzene is added as an antisolvent 16 s before the end of spin coating. Anneal at 130 ℃ for 30 min to prepare the perovskite light-absorbing layer. (4) Dissolve 72.3 mg Spiro-OMeTAD in 1 mL of chlorobenzene, and add 28.8 μL of TBP, 17.5 μL of Li-TFSI solution (concentration of 520 mg / mL, solvent of anhydrous acetonitrile) and 20 μL of FK209 (concentration of 200 mg / mL, solvent of anhydrous acetonitrile) to the Spiro-OMeTAD solution. After mixing, drop the solution onto the perovskite light-absorbing layer prepared in step (3), and spin coat at 3000 rpm for 30 s to prepare the hole transport layer. (5) In high vacuum (10 -4 Under the condition of Pa), an Ag electrode with a thickness of 100 nm is deposited on the hole transport layer obtained in step (4) by thermal evaporation to form a metal back electrode, thus obtaining an upright perovskite solar cell without dipole molecule modification of the buried interface. Example 1

[0023] The specific method for fabricating upright perovskite solar cells based on dipole molecule DP-modified buried interface is as follows: (1) The ITO conductive substrate is ultrasonically cleaned with detergent, deionized water and anhydrous ethanol for 20 min in sequence, dried with nitrogen, treated with ultraviolet ozone for 15 min and cooled to obtain the pretreated ITO conductive substrate for use. (2) Add 200 μL of ammonia solution with a mass fraction of 28% and 200 μL of RbCl solution with a concentration of 3 mg / mL to 200 μL of SnO2 nanoparticle dispersion with a mass fraction of 12%. Mix well to obtain a SnO2 dispersion treated with ammonia and RbCl. Filter the dispersion through 0.22 μm PVDF. Take 40 μL and drop it onto the ITO conductive substrate pretreated in step (1). Spin coat at 3000 rpm for 30 s. Then anneal at 100 ℃ for 30 min. Finally, perform ultraviolet ozone treatment for 20 min to prepare the electron transport layer. (3) Add 40 μL of DP dispersion with a concentration of 0.2 mg / mL to the electron transport layer after step (2), spin coat at 5000 rpm for 30 s, and then anneal at 100 ℃ for 10 min to prepare the DP-modified buried interface, which is the dipole molecule modified layer. (4) Dissolve 18.75 mg MABr, 6.15 mg PbBr2, 19.58 mg CsI, 33 mg MACl, 246.28 mg FAI, and 764.45 mg PbI2 in 1 mL of a mixed solvent of DMF and DMSO (V DMF :V DMSO = 4:1), shake for 1 h to obtain a perovskite precursor solution with a concentration of 1.675 mol / L. Then, the perovskite precursor solution is filtered through 0.22 μm PTFE, and 40 μL is added to the dipole molecule modified layer prepared in step (3). First, spin coat at 1000 rpm for 10 s, then spin coat at 5000 rpm for 30 s. 80 μL of chlorobenzene is added as an antisolvent 16 s before the end of spin coating. Anneal at 130 ℃ for 30 min to prepare the perovskite light-absorbing layer. (5) Dissolve 72.3 mg Spiro-OMeTAD in 1 mL of chlorobenzene, and add 28.8 μL of TBP, 17.5 μL of Li-TFSI solution (concentration of 520 mg / mL, solvent of anhydrous acetonitrile) and 20 μL of FK209 (concentration of 200 mg / mL, solvent of anhydrous acetonitrile) to the Spiro-OMeTAD solution. After mixing, drop the solution onto the perovskite light-absorbing layer prepared in step (3), and spin coat at 3000 rpm for 30 s to prepare the hole transport layer. (6) In high vacuum (10-4 Under the condition of Pa), an Ag electrode with a thickness of 100 nm is deposited on the hole transport layer obtained in step (4) by thermal evaporation to form a metal back electrode, thereby obtaining an upright perovskite solar cell based on the buried interface modified by the dipole molecule DP. Example 2

[0024] The specific method for fabricating upright perovskite solar cells based on DA-modified buried interfaces with dipole molecules is as follows: Compared with Example 1, Example 2 replaced the DP solution with a concentration of 0.2 mg / mL in step (3) with a DA solution with a concentration of 0.4 mg / mL. The other preparation process was exactly the same as in Example 1, and an upright perovskite solar cell based on the DA-modified buried interface of the dipole molecule was prepared. Example 3

[0025] The specific method for fabricating upright perovskite solar cells based on DD-modified buried interfaces is as follows: Compared with Example 1, Example 3 replaced the DP solution with a concentration of 0.2 mg / mL in step (3) with a DD solution with a concentration of 0.3 mg / mL. The other preparation process was exactly the same as in Example 1, and a positive perovskite solar cell based on the buried interface modified by the dipole molecule DD was obtained. Example 4

[0026] The specific method for fabricating upright perovskite solar cells based on dipole molecule-modified buried interface is as follows: (1) The FTO conductive substrate is ultrasonically cleaned with detergent, deionized water and anhydrous ethanol for 10 min in sequence, dried with nitrogen, treated with ultraviolet ozone for 10 min and cooled to obtain the pretreated FTO conductive substrate for use. (2) Add 200 μL of ammonia solution with a mass fraction of 28% and 200 μL of RbCl solution with a concentration of 3 mg / mL to 200 μL of TiO2 nanoparticle dispersion with a mass fraction of 12%. Mix well to obtain a SnO2 dispersion treated with ammonia and RbCl. Filter the dispersion through 0.22 μm PVDF. Take 40 μL and drop it onto the ITO conductive substrate pretreated in step (1). Spin coat at 3000 rpm for 30 s. Then anneal at 170 ℃ for 30 min. Finally, perform ultraviolet ozone treatment for 20 min to prepare the electron transport layer. (3) Add 40 μL of DP dispersion with a concentration of 0.2 mg / mL to the electron transport layer after step (2), spin coat at 5000 rpm for 30 s, and then anneal at 100 ℃ for 10 min to prepare the DP-modified buried interface, which is the dipole molecule modified layer. (4) Dissolve 18.75 mg MABr, 6.15 mg PbBr2, 19.58 mg CsI, 33 mg MACl, 246.28 mg FAI, and 764.45 mg PbI2 in 1 mL of a mixed solvent of DMF and DMSO (V DMF :V DMSO = 4:1), shake for 1 h to obtain a perovskite precursor solution with a concentration of 1.675 mol / L. Then, the perovskite precursor solution is filtered through 0.22 μm PTFE, and 40 μL is added to the dipole molecule modified layer prepared in step (3). First, spin coat at 1000 rpm for 10 s, then spin coat at 5000 rpm for 30 s. 80 μL of chlorobenzene (CB) is added as an antisolvent 16 s before the end of spin coating. Anneal at 130℃ for 30 min to prepare the perovskite light-absorbing layer. (5) Dissolve 72.3 mg of 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene (Spiro-OMeTAD) in 1 mL of chlorobenzene, and add 28.8 μL of TBP, 17.5 μL of Li-TFSI solution (concentration of 520 mg / mL, solvent of anhydrous acetonitrile) and 20 μL of FK209 (concentration of 200 mg / mL, solvent of anhydrous acetonitrile) to the 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene (Spiro-OMeTAD) solution, mix well and drop onto the perovskite light-absorbing layer prepared in step (3), spin-coat at 3000 rpm for 30 s to prepare the hole transport layer; (6) In high vacuum (10 -4 Under the condition of Pa), an Ag electrode with a thickness of 100 nm is deposited on the hole transport layer obtained in step (4) by thermal evaporation to form a metal back electrode, thereby obtaining an upright perovskite solar cell based on the buried interface modified by the dipole molecule DA. Example 5

[0027] The specific method for fabricating upright perovskite solar cells based on dipole molecule-modified buried interface is as follows: (1) The FTO conductive substrate is ultrasonically cleaned with detergent, deionized water and anhydrous ethanol for 40 min in sequence, dried with nitrogen, treated with ultraviolet ozone for 50 min and cooled to obtain the pretreated FTO conductive substrate for use. (2) Add 200 μL of ammonia solution with a mass fraction of 28% and 200 μL of RbCl solution with a concentration of 3 mg / mL to 200 μL of ZnO2 nanoparticle dispersion with a mass fraction of 12%. Mix well to obtain a SnO2 dispersion treated with ammonia and RbCl. Filter the dispersion through 0.22 μm PVDF. Take 40 μL and drop it onto the ITO conductive substrate pretreated in step (1). Spin coat at 3000 rpm for 30 s. Then anneal at 100 ℃ for 3 min. Finally, perform ultraviolet ozone treatment for 20 min to prepare the electron transport layer. (3) 40 μL of DP dispersion with a concentration of 0.02 mg / mL (solvent is isopropanol) is dropped onto the electron transport layer after step (2), spin-coated at 5000 rpm for 30 s, and then annealed at 100 ℃ for 10 min to prepare the DP-modified buried interface, which is the dipole molecule modified layer. (4) Dissolve 18.75 mg MABr, 6.15 mg PbBr2, 19.58 mg CsI, 33 mg MACl, 246.28 mg FAI, and 764.45 mg PbI2 in 1 mL of a mixed solvent of DMF and DMSO (V DMF :V DMSO = 4:1), shake for 1 h to obtain a perovskite precursor solution with a concentration of 1.675 mol / L. Then, the perovskite precursor solution is filtered through 0.22 μm PTFE, and 40 μL is added to the dipole molecule modified layer prepared in step (3). First, spin coat at 1000 rpm for 10 s, then spin coat at 5000 rpm for 30 s. 80 μL of chlorobenzene is added as an antisolvent 16 s before the end of spin coating. Anneal at 130 ℃ for 30 min to prepare the perovskite light-absorbing layer. (5) Dissolve 72.3 mg of 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene (Spiro-OMeTAD) in 1 mL of chlorobenzene, and add 28.8 μL of TBP, 17.5 μL of Li-TFSI solution (concentration of 520 mg / mL, solvent of anhydrous acetonitrile) and 20 μL of FK209 (concentration of 200 mg / mL, solvent of anhydrous acetonitrile) to the 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene (Spiro-OMeTAD) solution, mix well and drop onto the perovskite light-absorbing layer prepared in step (3), spin-coat at 3000 rpm for 30 s to prepare the hole transport layer; (6) In high vacuum (10 -4 Under the condition of Pa), an Ag electrode with a thickness of 100 nm is deposited on the hole transport layer obtained in step (4) by thermal evaporation to form a metal back electrode, thereby obtaining an upright perovskite solar cell based on the buried interface modified by the dipole molecule DA.

[0028] Performance testing Figure 1 In Figure a, the electrostatic potential distribution of the dipolar molecules DA, DD, and DP used in Examples 1-3 are shown respectively; in Figure b, the optimal configurations and binding energies of DA, DD, and DP adsorbed on the SnO2 surface are shown; and in Figures c and d, the optimal configurations and binding energies of DA, DD, and DP adsorbed on the perovskite surface are shown respectively. Figure 1 As shown in Figure a, the electron cloud density preferentially distributes around the highly polar P=O (in DP) and C=O (in DA, DD, and DP) functional groups. Notably, the P=O group in DP exhibits a significantly higher negative electron cloud density, indicating that the P=O group has a superior electron donor capability in coordination with common Lewis acid defects (undercoordinated metal cations on the perovskite surface). This suggests that the P=O and two C=O groups in the multi-site DP molecule should exhibit excellent synergistic defect passivation. Furthermore, compared to DA, DP and DD possess larger dipole moments, indicating their potential to induce a stronger interfacial electric field, thereby promoting energy level alignment at the ETL / perovskite interface and improving charge extraction efficiency. Figure 1 As shown in b, for those with V O Defective SnO2 surface, E b The order is: DP (-3.28 eV) > DD (-2.28 eV) > DA (-2.22 eV). Compared with DD and DA, DP has significantly stronger chemical bonds, mainly attributed to the P=O and C=O groups and their interaction with Sn. 4+ The co-coordination effect is consistent with the ESP results. Similarly, such as Figure 1 As shown in c, for those containing V I For defective perovskite surfaces, the binding energy order is E b (DP) (-1.75 eV) > E b (DD) (-1.63 eV) > E b (DA) (-1.54 eV). The P=O and C=O groups can react with V... I Possible Pb in the surrounding area 2+ The ions form effective coordination bonds. Although the absolute energy difference is smaller than that on SnO2, DP consistently exhibits the strongest interaction, further confirming the crucial role of the P=O group. Figure 1 As shown in Figure d, the adsorption of DP is mainly due to the interaction between its terminal ethoxyalkyl hydrogen and the surrounding I. - Dominated by multiple weak electrostatic interactions between ions. The cumulative effect of these different interactions leads to a stable total binding energy and a comprehensive Vg. FA Saturation. For DD, its binding originates from imide NH and I. - The interactions between ions, and the hydrogen bonds between its carbonyl oxygen and the nearby FA cation. For DA, although its carboxylic acid hydrogen can interact with I... - Interacting, but the carbonyl oxygen of the same group and I - The mutual repulsion between them weakens the overall adsorption, resulting in its E b The lowest value among the three. In summary, DP exhibits excellent passivation ability for various defects and is suitable for preparing buried interfaces for nip-type PSCs.

[0029] Figure 2 The images show the FTIR spectra of the DP and SnO2 / DP films from Example 1. Figure 2 As can be seen from the data, the peak of the P=O stretching vibration of pure DP is located at 1243.49 cm⁻¹. -1 At that location, after interacting with SnO2, due to the interaction between the P=O group and Sn... 4+ The coordination bonding resulted in a small wavenumber shift (1202.00 cm⁻¹) in the P=O group. -1 Meanwhile, the C=O stretching vibration peak increased from 1716.83 cm⁻¹. -1 Moved to 1708.75 cm -1 This is attributed to C=O and Sn 4+ The coordination effect of Sn. These shifts are attributed to the redistribution of electron density on the P=O and C=O functional groups, which weakens the bond strength and lowers their vibrational frequencies. This indicates that the P=O and C=O groups can simultaneously coordinate with Sn. 4+ Coordination, but the former is much stronger than the latter, further confirming the importance of introducing P=O groups into IDMs.

[0030] Figure 3 In Figure a and b, the Sn 3d and O1s XPS images of the SnO2 film in the comparative example and the SnO2 / DP film in Example 1, respectively, are shown. Figure 3 As can be seen from a, after DP processing, Sn 3d 3 / 2 and Sn 3d 5 / 2 The binding energies of the characteristic peaks shifted from 494.71 eV and 486.30 eV to 495.31 eV and 486.88 eV, respectively, confirming the binding energies of P=O and C=O with Sn. 4+ Coordinate bonding. For example... Figure 3 As shown in Figure b, for the original SnO2 thin film, the two main peaks are located at 530.62 eV (lattice oxygen, O). L ) and 531.93 eV (oxygen vacancy, O V After DP modification, these peaks shifted to 530.83 eV and 532.23 eV, respectively. Furthermore, O... L The peak area ratio increased from 68.77% to 87.69%, confirming that P=O and C=O support the undercoordinated Sn. 4+ Or effective passivation of oxygen vacancy defects.

[0031] Figure 4 In Figure 1, a and b are the AFM images of the SnO2 film in the comparative example and the SnO2 / DP film in Example 1, respectively. From... Figure 4 As can be seen, the surface roughness of the SnO2 film decreased from 0.85 nm to 0.78 nm after DP modification. The decrease in roughness indicates that DP modification makes the SnO2 / DP film more dense and uniform. This smoothed surface structure helps to improve interfacial contact, thereby providing favorable conditions for charge transport.

[0032] Figure 5 In Figure 1, a and b are the KPFM diagrams of the SnO2 film in the comparative example and the SnO2 / DP film in Example 1, respectively. From... Figure 5 As can be seen from the comparison, the SnO2 thin film sample modified by DP exhibits a higher surface potential and a more uniform surface potential distribution, indicating that DP can effectively regulate and improve the surface electrical properties of SnO2 thin film, thereby forming a channel that is more conducive to charge transport.

[0033] Figure 6 In the figures, a and b represent the electrical conductivity and electron mobility of the SnO2 film in the comparative example and the SnO2 / DP film in Example 1, respectively. Figure 6 As shown in Figure a, the SnO2 / DP film exhibits higher conductivity compared to pure SnO2. The conductivity of the SnO2 / DP film is determined to be 9.22 × 10⁻⁶ based on the JV characteristics.-3 mS·cm -1 It is the original SnO2 (6.42×10⁻⁶). -3 mS·cm -1 The electron mobility was 1.44 times that of the original SnO2 film. Meanwhile, the electron mobility increased from 3.12 × 10⁻⁶ for the original SnO2 film. -3 cm 2 ·V -1 ·S -1 Increased to 3.82 × 10⁻⁶ for SnO₂ / DP thin films -3 cm 2 ·V -1 ·S -1 ,like Figure 6 As shown in Figure b, the increased conductivity and electron mobility can facilitate efficient charge transport and extraction in photovoltaic devices, primarily due to the passivation of oxygen vacancies and uncoordinated Sn by DP. 4+ defect.

[0034] Figure 7 The images show the FTIR spectra of DP, DP+PbI2, and DP+FAI in Example 1. Figure 7 As shown, after mixing with FAI, the C=O and P=O stretching vibrations in DP decreased from 1718.50 cm⁻¹. -1 Moved to 1715.72 cm -1 And from 1244.03 cm -1 Moved to 1240.18 cm -1 This confirms that C=O and P=O are related to FA. + The interaction between them. Similarly, after mixing with PbI2, the C=O and P=O peaks of DP shifted to 1714.96 cm⁻¹, respectively. -1 and 1191.96 cm -1 This indicates that oxygen-containing groups can react with Pb. 2+ Strong coordination bonds are formed.

[0035] Figure 8 In the comparison example, 'a' represents the FAI in the comparative example and the DP+FAI in Example 1. 1 H NMR spectra, b represents FAI in the comparative example and DP, DP+FAI and DP+PbI2 in Example 1. 13 C10 NMR spectra, where c represents DP, DP+FAI, and DP+PbI2 from Example 1. 31 pNMR spectrum. From Figure 8 As can be seen in a, compared to the pure FAI molecule, the -NH2 (position 1) signal of FAI in DP+FAI is split, and the H at position 2 undergoes a chemical shift. This change indicates that a hydrogen bond has formed between FAI and DP, and... Figure 1 The theoretical calculation results are consistent. From... Figure 8 As can be seen from b, firstly, the characteristic peaks related to C=O (positions 7 and 8) have shifted, confirming that C=O in DP interacts with both FAI and PbI2; furthermore, the chemical shift of the DP+FAI solution shifts to higher fields, indicating that FAI... + Hydrogen bonds formed between DP and DP. From Figure 8 As can be seen from c, after mixing with FAI and PbI2, the chemical shift of P=O in the DP molecule shifts to a lower field, further confirming the interaction between P=O and FAI. + or Pb 2+ The strong coordination between them is beneficial for passivating uncoordinated FA or Pb defects.

[0036] Figure 9 Image a shows the Pb 4f XPS plots of the PVSK film in the comparative example and the DP / PVSK film in Example 1; image b shows the N 1s XPS plots of the DP and DP / PVSK films in Example 1; and image c shows the I 3d XPS plots of the PVSK film in the comparative example and the DP / PVSK film in Example 1. Figure 9 As can be seen from a, after DP processing, Pb 4f 5 / 2 and Pb 4f 7 / 2 The peaks shifted from 142.38 eV and 137.50 eV to 143.30 eV and 138.46 eV, respectively, which is attributed to the P=O and / or C=O in DP with undercoordinated Pb. 2+ The coordination effect between them. From Figure 9 As can be seen from b, the shift in the binding energy of the N 1s peak indicates the presence of hydrogen bonds or coordination bonds between DP and perovskite. From... Figure 9 As can be seen from c, the shift of the I 3d peak further verifies the relationship between P=O and C=O and I. - Hydrogen bonding between them.

[0037] Figure 10 In Figure 1, a and b are the GIXRD patterns of the unmodified perovskite film (Control) prepared in the comparative example and the DP-modified perovskite film (DP) in Example 1, respectively. Figure 2 is the (211) crystal plane of the unmodified perovskite film (Control) prepared in the comparative example and the DP-modified perovskite film (DP) in Example 1. The function graph. From Figure 10As can be seen, for the control film, the characteristic peaks gradually shift to lower angles as the incident angle increases, which is attributed to the interfacial tensile stress caused by lattice expansion. In contrast, the variation in interplanar spacing of the DP-modified perovskite film at different incident angles is significantly reduced, indicating that the interfacial tensile stress is significantly released. The small shift in diffraction peaks and the subtle changes in d-interface spacing indicate that the tensile strain of the DP-modified film is significantly reduced. This is mainly attributed to the effective passivation of internal defects in the perovskite by DP's interfacial modulation.

[0038] Figure 11 In Figure 1, a and b are PL mapping images of the unmodified perovskite film (Control) prepared in the comparative example and the DP-modified perovskite film (DP) in Example 1, respectively. From... Figure 11 It can be seen that the PL intensity of the DP-modified perovskite film in Example 1 is significantly higher than that of the control perovskite film in the comparative example. This is because DP effectively passivates the defects on the bottom surface of the perovskite film, which significantly suppresses the non-radiative recombination caused by traps.

[0039] Figure 12 SCLC images of a pure electronic device (ITO / SnO2 (or SnO2 / DP) / PVSK / PCBM / BCP / Ag) prepared in the comparative examples and the DP-modified perovskite film (DP) in Example 1 are shown. Figure 12 As shown, the V of the control device TFL The initial voltage was 0.25 V, which was reduced to 0.14 V after DP modification. The calculated defect state density of the control device was 4.14 × 10⁻⁶. 15 cm -3 The defect density of the DP-modified device was significantly reduced to 2.31 × 10⁻⁶. 15 cm -3 This further confirms the effectiveness of DP in passivating defects on the bottom surface of perovskite films. After DP modification, defect passivation, improved crystallinity, and reduced residual stress are likely the main reasons for the reduction in trapped states.

[0040] Figure 13 In Figure 1, a and b are SEM images of the surface of the perovskite film (Control) without dipole molecule modification prepared in the comparative example and the perovskite film (DP) modified with DP in Example 1, respectively. Figures c and d show the corresponding grain size distribution statistics. Figure 13As shown, the average grain size of the perovskite film deposited on SnO2 is 876.8 nm, and obvious grain boundaries and a small amount of PbI2 residue can be observed on the film surface. In contrast, the average grain size of the perovskite film deposited on the SnO2 / DP substrate is significantly increased to 1145.5 nm, the PbI2 content at the grain boundaries is significantly reduced, and the film is more uniform and dense.

[0041] Figure 14 In Figure 1, a and b are SEM images of the bottom surfaces of the perovskite film (Control) prepared in the comparative example without dipole molecule modification and the perovskite film (DP) modified in Example 1, respectively. Figures c and d show the corresponding grain size distribution statistics. Figure 14 As shown, the perovskite buried interface in the control sample exhibits numerous pores and discontinuous regions, with a statistically average grain size of 970.6 nm. In contrast, the perovskite substrate surface in the DP-modified sample is smoother and denser, with a grain size increasing to 1162.2 nm, and the porosity at the interface is significantly reduced. These results demonstrate that DP modification optimizes the surface properties of the SnO2 substrate, inducing the growth of large grains, high crystallinity, and low defect density in perovskite films. Simultaneously, it significantly improves the contact quality at the buried interface, which is beneficial for reducing non-radiative recombination losses and improving carrier extraction efficiency.

[0042] Figure 15 In the comparative examples, a and b represent the SnO content in SnO2, respectively. x The unmodified perovskite film (Glass / ITO / SnO2 / PVSK) prepared on the substrate and the SnO2 film in Example 1 x PL and TRPL spectra of DP-modified perovskite films (Glass / ITO / SnO2 / DP / PVSK) prepared on a DP substrate. Figure 15 As shown, SnO2 / DP / perovskite (in Example 1, SnO2 / DP / perovskite) x The average PL lifetime of the DP-modified perovskite film (Glass / ITO / SnO2 / DP / PV SK) prepared on the DP substrate was shortened to 233.4 ns, while the unmodified control sample (in the comparative example on SnO2) had a significantly shorter average PL lifetime. x The average PL lifetime of the unmodified perovskite films (Glass / ITO / SnO2 / PVSK) prepared on the substrate was 351.4 ns (as shown in Table 1). This shortened lifetime indicates efficient electron extraction at the SnO2 / DP / perovsk interface and suppression of trap-assisted nonradiative recombination, which is related to the reduction in interface defect density and improved energy level alignment. The shortened carrier lifetime is consistent with the decrease in steady-state PL intensity and more pronounced PL quenching.

[0043] Table 1 Fitting results of TRPL spectra Figure 16 To compare the current density-voltage curves of the unmodified perovskite solar cell device (Control) in Example 1 and the DP-modified perovskite solar cell device (DP) in Example 1, Table 2 shows the photovoltaic parameters of PSCs before and after DA, DD, and DP modification. Figure 16 The photovoltaic parameters of PSCs were obtained from the tests, as shown in Table 2. Figure 16 As shown in Table 2, the efficiency of perovskite solar cells in Examples 1, 2, and 3 is significantly improved, especially in Example 1. Due to the synergistic effect of multiple functional groups, the device modified with DP containing both P=O and C=O achieves a higher PCE, reaching 25.69% (J). SC 25.33 mA / cm 2 V OC With a V of 1.183 and an FF of 85.75%, this is one of the highest efficiencies reported for devices fabricated under ambient air conditions.

[0044] Table 2. Summary of photovoltaic parameters of control and PSCs modified with optimal concentrations of DA, DD, and DP. Figure 17 To compare the stability of the unmodified perovskite solar cell device (Control) in Example 1 and the DP-modified perovskite solar cell device (DP) in Example 1 under an environment with a humidity of 20-30%. Figure 17 As shown, after aging for 1944 h, the PCE of the DP-modified upright perovskite solar cell in Example 1 remained at 93.92% of its initial value, while the control device in the comparative example only maintained 81.05%, indicating a significantly faster degradation rate. This result demonstrates that DP modification significantly improves the humidity stability of the device.

[0045] Figure 18 To compare the stability of the unmodified perovskite solar cell device (Control) in the examples and the DP-modified perovskite solar cell device (DP) in Example 1 under continuous maximum power point (MPP) tracking. Figure 18 As shown, after 782 hours of aging, the PCE of the control device decreased to 65.26% of the initial value, while the DP-modified device maintained an initial efficiency of 90.82%, with a significant reduction in degradation.

[0046] Similarly, a comparison of the performance of the upright perovskite solar cells based on the dipole molecule-modified buried interface prepared in Examples 1, 4, and 5 with the upright perovskite solar cells without the dipole molecule-modified buried interface in the comparative examples shows that... In summary, this invention discloses a strategy for achieving high-efficiency and stable upright perovskite solar cells by modifying the SnO2 / perovskite interface with a multi-site IDM. The synergistic effect of C=O and P=O groups in the dipole molecules (DP, DA, or DD) enables bidirectional defect passivation, reduces residual tensile stress at the interface, optimizes energy level alignment, and enhances buried interface contact, thereby improving the quality and durability of the buried interface. This facilitates interface electron extraction and suppresses nonradiative recombination of interface carriers. The upright perovskite solar cell modified with DP achieved a champion efficiency of 25.68%, one of the highest efficiencies reported to date for upright PSCs processed in air. Importantly, the DP-modified device exhibited excellent operational stability, maintaining an initial efficiency of 90.82% after 782 h of MPP operation at 40 ± 5 °C. This work provides an effective method for stabilizing the buried interface through the rational design of multi-site IDM. This strategy significantly reduces the dependence of high-efficiency and stable perovskite solar cells on inert gas environments, laying a solid foundation for the industrial deployment of low-cost, high-performance perovskite photovoltaic technology.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A positive perovskite solar cell based on a buried interface modified with dipole molecules, characterized in that, The upright perovskite solar cell has a dipole molecular modification layer between the perovskite light-absorbing layer and the electron transport layer, which serves as the material for the dipole molecular modification layer.

2. The upright perovskite solar cell according to claim 1, characterized in that, The dipole molecule is any one of phthaloylglycine, phthalimide, and diethyl phthaloyldiimide methyl phosphate, and its chemical structural formula is: 。 3. The upright perovskite solar cell according to claim 1, characterized in that, The upright perovskite solar cell comprises, from bottom to top, a conductive substrate layer, an electron transport layer, a dipole molecule modification layer, a perovskite light-absorbing layer, a hole transport layer, and a metal back electrode.

4. The upright perovskite solar cell according to claim 3, characterized in that, The conductive substrate is either ITO or FTO. The electron transport layer is made of any one or more of tin dioxide, titanium dioxide, or zinc oxide. The material of the perovskite light-absorbing layer is ABX3 type perovskite, wherein A is any one or more of methylamine ions, formamidinium ions, or cesium ions, B is any one or more of lead ions or tin ions, and X is any one or more of iodide ions, bromide ions, or chloride ions. The hole transport layer is made of any one or more of 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], poly(3-hexylthiophene-2,5-diyl) or nickel oxide; The material of the back electrode layer is any one of Au, Ag, or low-temperature carbon electrode.

5. The method for preparing an upright perovskite solar cell according to any one of claims 1 to 4, characterized in that, The preparation method includes the following steps: (1) The electron transport layer material solution was spin-coated onto a pretreated conductive substrate and then subjected to annealing and ultraviolet ozone irradiation treatment to prepare the electron transport layer. (2) Spin-coat the solution of the dipole molecules onto the electron transport layer prepared in step (1), and anneal the layer to obtain the dipole molecule modified layer. (3) The solution of the perovskite precursor material is dropped onto the dipole molecule modified layer prepared in step (2), and after spin coating, an antisolvent is added and then annealed to obtain the perovskite light-absorbing layer. (4) Spin-coat the hole transport layer material solution onto the perovskite light-absorbing layer prepared in step (3) to obtain the hole transport layer; (5) The metal back electrode material is deposited on the hole transport layer prepared in step (4) to obtain the upright perovskite solar cell based on the buried interface modified by dipole molecules.

6. The preparation method according to claim 5, characterized in that, In step (1), the pretreatment method of the conductive substrate is specifically as follows: the conductive substrate is cleaned and then subjected to ultraviolet ozone pretreatment or plasma pretreatment. The method of ultraviolet ozone pretreatment is as follows: the conductive substrate is ultrasonically cleaned sequentially with detergent, deionized water, and anhydrous ethanol, then dried with nitrogen gas, and treated with ultraviolet ozone for 10-50 min.

7. The preparation method according to claim 5, characterized in that, In step (1), the spin coating speed is 1000~5000 rpm and the time is 20~60 s, and the annealing temperature is 80~150 ℃ and the time is 5~30 min; The ultraviolet ozone treatment time is 10~50 min.

8. The preparation method according to claim 5, characterized in that, In step (2), the concentration of the dipole molecules in the solution is 0.1 to 10 mg / mL, and the solvent in the solution is any one or more of dichloromethane, chloroform, chlorobenzene, dichlorobenzene, toluene, ethyl acetate or isopropanol. The spin coating speed is 2000~6000 rpm and the time is 10~50 s, and the annealing temperature is 80~150 ℃ and the time is 10~50 min.

9. The preparation method according to claim 5, characterized in that, In step (3), the antisolvent is any one or more of chlorobenzene, dichloromethane, toluene, ethyl acetate, chloroform or diethyl ether; The spin coating process is carried out in two steps: first, spin coating is performed at a speed of 1000-3000 rps for 10-60 s, and then spin coating is performed at a speed of 2000-6000 rps for 20-60 s. The annealing temperature is 100~150 ℃ and the annealing time is 20~50 min.

10. The preparation method according to claim 5, characterized in that, In step (4), the spin coating speed is 2000~6500 rpm and the time is 20~60 s.

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