Perovskite solar cell based on co-self-assembly molecule-induced interface in-situ polymerization and preparation method thereof

Abstract

The invention discloses a perovskite solar cell based on co-self-assembly molecule-induced interface in-situ polymerization and a preparation method thereof. The perovskite solar cell comprises a nickel oxide layer, a co-self-assembly layer, an in-situ polymer layer, a perovskite layer, a passivation layer, an electron transport layer and a top electrode which are sequentially arranged on the surface of a substrate, wherein the in-situ polymer layer is arranged between the co-self-assembly layer and the perovskite layer, the co-self-assembly layer comprises co-self-assembly molecules, and the co-self-assembly molecules are formed by mixing first self-assembly molecules and second self-assembly molecules with sulfydryl at the tail end; a perovskite layer precursor solution for preparing the perovskite layer comprises ionic liquid, and the cation part of the ionic liquid contains end groups of carbon-carbon double bonds. Based on dual mechanisms of co-self-assembly molecules and in-situ polymerization, the defects of a perovskite buried interface can be effectively passivated, interface contact is enhanced, and the photoelectric conversion efficiency and long-term stability of the perovskite cell can be remarkably improved.

Description

Technical Field

[0001] The present invention relates to a perovskite solar cell based on co - self - assembled molecule - induced in - situ polymerization at the interface and a manufacturing method thereof, belonging to the technical field of perovskite solar cells. Background Art

[0002] In recent years, in the field of renewable energy, inverted perovskite solar cells (IPSCs) have received extensive attention due to their excellent photoelectric conversion efficiency and flexible fabrication process. The introduction of self - assembled molecules (SAMs) has greatly improved the photoelectric conversion efficiency of the cells. However, the existing self - assembled molecular layers are mainly adsorbed on the surface of the transparent conductive layer / metal oxide by chemical methods, but there are still some problems in the actual anchoring process. First, during the self - assembly process of SAM molecules on the oxide surface, due to insufficient intermolecular forces and poor anchoring ability, the coverage is often uneven. This unevenness leads to local charge accumulation, which in turn affects the photoelectric conversion efficiency. In addition, during the formation of the self - assembled monolayer film, the steric hindrance effect of the molecular chain may cause hindrance to the molecular arrangement, and its distribution characteristics are easily regulated by environmental parameters (such as temperature, substrate topography, etc.), thereby forming a heterogeneous micro - region structure, resulting in deteriorated interface contact and blocked carrier transport, ultimately significantly weakening the performance and stability of the device. These defects limit the application of SAMs in high - efficiency perovskite solar cells.

[0003] In recent years, in order to enhance the anchoring ability of self - assembled molecules and improve their coverage, researchers have made various attempts. The patent with the publication number CN119192239A discloses a novel SAM hole - transporting material containing a phenanthro - triazole moiety, where phenanthro - triazole serves as the parent nucleus and the phosphonic acid moiety serves as the anchoring group. Phenanthro - triazole has the characteristic of a larger conjugated plane, which is beneficial to intermolecular stacking and charge transport. At the same time, the introduction of triazole increases the dipole moment of the molecule, which is beneficial to hole extraction. This SAM hole - transporting material is used in inverted perovskite solar cells and has good solubility and wettability while having a strong anchoring ability. The patent with the publication number CN118555884A discloses a method for improving the surface properties of the substrate through plasma treatment or chemical modification to enhance the coverage effect of SAM. The structure of the perovskite solar cell is a conductive substrate, nickel oxide NiO x / SAM hole - transporting layer, perovskite light - absorbing layer, electron - transporting layer, blocking layer and top electrode. Among them, the surface of NiO x is subjected to O 2 plasma treatment for different times, and then a SAM solution is spin - coated to form a film. Tests show that after O 2 plasma treatment of NiO xAfter the surface, the surface roughness of the hole transport layer is reduced, and the film conductivity is enhanced. The present invention realizes the uniform and robust anchoring of SAM molecules through the improvement of the NiO x film surface, thereby promoting charge extraction and suppressing interfacial non-radiative recombination. A patent with publication number CN118922003A discloses a strategy for hybrid SAMs, in which the surface of nickel oxide is modified by preparing hybrid SAMs by regulating the contents of 6-(iodo-λ5-azanyl)hexanoic acid compounds (I) and 4-(9-carbazolyl)-butyl phosphonate compounds (II) with different chain lengths. Among them, the mass percentage content of compound (I) in the hole modification layer is a, 30% ≤ a ≤ 70%, and the mass percentage content of compound (II) in the hole modification layer is b, 30% ≤ b ≤ 70%, which is more conducive to obtaining a hole modification layer with excellent interfacial modification ability and passivation ability. However, although the above several methods can enhance the anchoring ability of SAMs to the oxide surface to a certain extent and solve the problems of low coverage and uneven distribution existing in the application of existing self-assembled monolayers in inverted perovskite solar cells, the key technical problems of the interfacial contact between the SAM layer and the lower surface of the perovskite and the peeling off of the perovskite film caused by the interfacial contact problem under the action of long-term temperature and humidity, resulting in the decline of the long-term stability of the perovskite battery, have not been properly solved. Therefore, developing SAM-based inverted perovskite solar cells that can effectively improve the photoelectric efficiency and have excellent long-term stability is one of the technical problems that need to be solved in this field at present. Summary of the Invention

[0004] The main object of the present invention is to provide a perovskite solar cell and a manufacturing method based on co-self-assembled molecule-induced interfacial in-situ polymerization to overcome the deficiencies in the prior art.

[0005] To achieve the foregoing invention object, the technical solutions adopted by the present invention include: An embodiment of the present invention provides a perovskite solar cell based on co-self-assembled molecule-induced interfacial in-situ polymerization, which includes: a nickel oxide layer, a co-self-assembled layer, an in-situ polymer layer, a perovskite layer, a passivation layer, an electron transport layer, and a top electrode sequentially disposed on the surface of a substrate; Among them, the in-situ polymer layer is disposed between the co-self-assembled layer and the perovskite layer. The co-self-assembled layer includes co-self-assembled molecules, and the co-self-assembled molecules are formed by mixing a first self-assembled molecule and a second self-assembled molecule containing a mercapto group at the end; the perovskite layer precursor solution for preparing the perovskite layer includes an ionic liquid, and the cation part of the ionic liquid contains a terminal group with a carbon-carbon double bond; the in-situ polymer layer is formed by in-situ polymerization of the second self-assembled molecule and the ionic liquid; The first self-assembled molecule has a structure shown in formula (I), and the second self-assembled molecule has a structure shown in formula (II) and / or formula (III): Among them, 2 ≤ n ≤ 5, 3 ≤ x ≤ 12, and 2 ≤ y ≤ 12.

[0006] The embodiment of the present invention also provides a preparation method of the perovskite solar cell based on co - self - assembly molecule - induced in - situ polymerization, which includes: Providing a substrate; And sequentially preparing a nickel oxide layer, a co - self - assembly layer, an in - situ polymer layer, a perovskite layer, a passivation layer, an electron transport layer, a blocking layer, and a top electrode on the surface of the substrate, thereby obtaining a perovskite solar cell based on co - self - assembly molecule - induced in - situ polymerization.

[0007] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention adopts the Co - SAMs strategy constructed by SAM - 2 with a special structure. On the one hand, it strengthens the anchoring ability of the self - assembly molecule to the surface of the lower - layer oxide and improves its coverage rate; at the same time, combined with the in - situ free - radical polymerization reaction, it enhances the adhesion ability of the self - assembly molecule to the buried interface of the upper - layer perovskite, greatly improving the photoelectric conversion efficiency and long - term stability of the device. Brief Description of the Drawings

[0008] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments recorded in the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0009] Figure 1 It is a schematic cross - sectional structure diagram of the perovskite solar cell provided by the present invention; Figure 2 It is a surface roughness diagram of the self - assembly layer of the perovskite solar cells prepared in Example 1 and Comparative Example 1 of the present invention; Figure 3 It is a conductivity curve diagram of the perovskite solar cell samples prepared in Example 1 and Comparative Example 1 of the present invention; Figure 4 It is a surface morphology diagram of the perovskite solar cell thin films prepared in Example 1 and Comparative Example 1 of the present invention; Figure 5 It is a time - resolved fluorescence spectrum diagram of the perovskite solar cell thin films prepared in Example 1 and Comparative Example 1 - 2 of the present invention; Figure 6 It is an I - V curve diagram of the perovskite solar cell samples prepared in Example 1 and Comparative Example 1 - 2 of the present invention; Figures 7 - 8It is the bonding force curve graph of the perovskite solar cell thin films prepared in Example 1 of the present invention and Comparative Examples 1-2; Figure 9 It is the long-term stability curve graph of the perovskite solar cell samples prepared in Example 1 of the present invention and Comparative Example 1; Description of the drawings: 1 - transparent conductive substrate, 2 - nickel oxide layer, 3 - co-self-assembled layer, 4 - in-situ polymer layer, 5 - perovskite layer, 6 - passivation layer, 7 - electron transport layer, 8 - top electrode. Detailed implementation manners

[0010] In view of the defects of the prior art, through long-term research and a large number of practices by the inventors of this case, the technical solution of the present invention can be proposed. Mainly by using the Co-SAMs strategy, on the one hand, it enhances the anchoring ability of the co-self-assembled layer on the surface of the lower oxide layer, improves the coverage rate of the SAM hole transport layer, reduces the surface roughness of the SAM and increases the conductivity, which is beneficial to the extraction of holes and the adaptation of interface energy levels; on the other hand, it enhances the interfacial adhesion between the co-self-assembled layer and the upper perovskite interface. By introducing a new SAM material with a special end group (such as a mercapto group), the in-situ polymer POL-AVM is formed in-situ at the buried bottom interface of the perovskite by the in-situ polymerization reaction of the active mercapto end group of Co-SAMs and the carbon-carbon double bond under heating conditions. Through this dual mechanism based on Co-SAMs and in-situ polymerization, it can not only effectively passivate the defects at the buried bottom interface of the perovskite, inhibit non-radiative polymerization, enhance interfacial contact, but also significantly improve the photoelectric conversion efficiency and long-term stability of the perovskite solar cell.

[0011] To facilitate the understanding of this application, the following will describe this application in more detail. However, it should be understood that the present invention can be implemented in many different forms and is not limited to the embodiments or examples described herein. On the contrary, the purpose of providing these embodiments or examples is to make the understanding of the disclosure content of the present invention more thorough and comprehensive.

[0012] Specifically, as an aspect of the technical solution of the present invention, a perovskite solar cell based on co-self-assembled molecule-induced in-situ polymerization includes: a nickel oxide layer, a co-self-assembled layer, an in-situ polymer layer, a perovskite layer, a passivation layer, an electron transport layer, and a top electrode sequentially arranged on the surface of the substrate; Wherein, the in-situ polymer layer is arranged between the co-self-assembled layer and the perovskite layer, the co-self-assembled layer includes co-self-assembled molecules, and the co-self-assembled molecules are formed by mixing a first self-assembled molecule and a second self-assembled molecule with a mercapto group at the end; the perovskite layer precursor solution for preparing the perovskite layer includes an ionic liquid, and the cation part of the ionic liquid contains a carbon-carbon double bond end group; the in-situ polymer layer is formed by the in-situ polymerization of the second self-assembled molecule and the ionic liquid; The first self-assembled molecule has a structure shown in formula (I), and the second self-assembled molecule has a structure shown in formula (II) and / or formula (III): where 2 ≤ n ≤ 5, 3 ≤ x ≤ 12, and 2 ≤ y ≤ 12.

[0013] In the present invention, the second self-assembled molecule has a thiol end group, providing a binding site for in-situ free radical polymerization. The cationic part of the ionic liquid also has a terminal group with a carbon-carbon double bond. Therefore, a polymer layer is in-situ generated between the co-self-assembled layer and the perovskite layer by annealing heating, and this polymer layer can well improve the interfacial contact between the co-self-assembled layer and the perovskite layer.

[0014] In some more specific embodiments, a schematic cross-sectional structure diagram of the perovskite solar cell based on co-self-assembled molecule-induced interfacial in-situ polymerization in the present invention is as Figure 1 shown, including: a transparent conductive substrate 1, a nickel oxide layer 2, a co-self-assembled layer 3, an in-situ polymer layer 4, a perovskite layer 5, a passivation layer 6, an electron transport layer 7, and a top electrode 8.

[0015] The SAM-2 structural self-assembled molecule introduced in the present invention, the thiol end group can provide an initiation site for in-situ free radical polymerization, which is one of the necessary points for initiating free radical polymerization; introducing at least one ionic liquid of formula (IV) or formula (V) in the perovskite precursor solution, the cationic part of which contains a terminal group with a carbon-carbon double bond, which is the second necessary condition for initiating free radical polymerization; during the annealing heating process, the thiol initiates the free radical polymerization reaction of the carbon-carbon double bond, and a polymer layer is in-situ generated at the interface between the co-self-assembled layer and the perovskite layer.

[0016] In some embodiments, the ionic liquid has a structure shown in formula (IV) and / or formula (V): where 1 ≤ x 1 ≤ 3, 1 ≤ x 2 ≤ 3.

[0017] In some embodiments, the content of the first self-assembled molecule in the co-self-assembled molecule is 50 wt% - 75 wt%, and the content of the second self-assembled molecule is 25 wt% - 50 wt%.

[0018] In some embodiments, the perovskite solar cell includes a substrate and, in sequence on the surface of the substrate, a nickel oxide layer, a co-self-assembled layer, an in-situ polymer layer, a perovskite layer, a passivation layer, an electron transport layer, a blocking layer, and a top electrode.

[0019] In some more specific embodiments, the perovskite solar cell structure includes a substrate and a nickel oxide layer, a co - self - assembly layer, an in - situ polymer layer, a perovskite layer, a passivation layer, an electron transport layer, and a top electrode, which are sequentially disposed on the substrate.

[0020] Among them, the co - self - assembly layer is located between NiO x and the perovskite, and includes self - assembly molecules represented by the compound of formula (I), named SAM - 1. The introduced self - assembly molecules contain at least one of the compounds of formula (II) and formula (III), named SAM - 2.

[0021] Where 2 ≤ n ≤ 5, 3 ≤ x ≤ 12, 2 ≤ y ≤ 12.

[0022] The mass percentage content of SAM - 1 in the Co - SAMs is a, 50% ≤ a ≤ 75%, and the mass percentage content of SAM - 2 in the Co - SAMs is b, 25% ≤ b ≤ 50%.

[0023] Among them, the ionic liquid added to the perovskite layer precursor solution contains at least one of the ionic liquids represented by formula (IV) and formula (V), named AVMTF 2 。

[0024] Where 1 ≤ x 1 ≤ 3, 1 ≤ x 2 ≤ 3.

[0025] The concentration of the ionic liquid added to the perovskite layer precursor solution is 0.05 - 0.2 mg / mL.

[0026] In the present invention, the phosphoric acid anchoring end of SAM - 2 is used to enhance the anchoring ability of Co - SAMs molecules on the surface of the lower - layer NiO x so as to improve the coverage rate and uniformity of the co - self - assembly layer; the mercapto end group of SAM - 2, as an electron - withdrawing group, can not only passivate NiO xSurface defects, while providing contact sites for in-situ polymerization, during the annealing process, an in-situ radical polymerization reaction occurs with at least one of the ionic liquids of formula (IV) or formula (V) aggregated on the bottom surface of the perovskite to form a POL-AVM polymer. The formation of this polymer helps to further strengthen the adhesion between the co-self-assembled layer and the perovskite bottom interface. At the same time, POL-AVM forms multiple hydrogen bond interactions with the perovskite organic cations, further inhibiting the escape of organic cations, thereby reducing interface defects and enhancing the stability of the perovskite solar cell. Through this dual mechanism based on Co-SAMs and in-situ polymerization, not only can the defects at the buried bottom interface of the perovskite be effectively passivated and the interface contact be enhanced, but also the photoelectric conversion efficiency and long-term stability of the perovskite solar cell can be significantly improved.

[0027] As another aspect of the technical solution of the present invention, the preparation method of the perovskite solar cell based on co-self-assembled molecule-induced interface in-situ polymerization described above includes: Providing a substrate; And, sequentially preparing a nickel oxide layer, a co-self-assembled layer, an in-situ polymer layer, a perovskite layer, a passivation layer, an electron transport layer, a blocking layer, and a top electrode on the surface of the substrate, thereby obtaining a perovskite solar cell based on co-self-assembled molecule-induced interface in-situ polymerization.

[0028] In some embodiments, the preparation method specifically includes: cleaning the substrate, and then using a spin coating method to prepare a nickel oxide layer on the surface of the substrate and performing an annealing treatment.

[0029] Further, the substrate is a transparent conductive substrate, and the transparent conductive substrate includes an ITO substrate or an FTO transparent conductive glass substrate, and is not limited thereto.

[0030] Furthermore, the sheet resistance of the conductive glass ITO is 7-25 Ω, and the refractive index is 85-95%.

[0031] Further, the spin coating speed used in the spin coating method is 1500-3000 rpm.

[0032] Further, the annealing temperature of the annealing treatment is 150-200 °C.

[0033] Further, the annealing time of the annealing treatment is 15-30 min.

[0034] In some embodiments, the preparation method specifically includes: mixing a first self-assembled molecule with a second self-assembled molecule having a mercapto end group to form a mixed molecular solution, and then using a spin coating method to apply the co-self-assembled molecular solution on the surface of the nickel oxide layer and performing an annealing treatment to obtain a co-self-assembled layer.

[0035] Further, the concentration of the co - self - assembled molecular solution is 0.4 - 0.8 mg / mL, and the mass ratio of the first self - assembled molecule to the second self - assembled molecule is 1:1 - 3:1.

[0036] Further, the spin - coating speed used in the spin - coating method is 2000 - 4000 rpm.

[0037] Further, the annealing temperature of the annealing treatment is 100 - 150 °C.

[0038] Further, the annealing time of the annealing treatment is 10 - 15 min.

[0039] In some embodiments, the preparation method specifically includes: applying a perovskite layer precursor solution onto the surface of the co - self - assembled layer by spin - coating and performing annealing treatment to obtain a perovskite layer; wherein, the perovskite layer precursor solution includes a solute and a solvent; the solute includes any one or a combination of more than one of formamidinium hydroiodide, methylammonium bromide, lead iodide, lead bromide, methylamine hydrochloride, cesium iodide, potassium iodide, and ionic liquid, and is not limited thereto.

[0040] Further, the solvent includes a mixed solvent formed by DMF and DMSO, and is not limited thereto.

[0041] Further, an anti - solvent is added during the spin - coating process, and the anti - solvent includes any one or a combination of more than one of chlorobenzene, toluene, anisole, and is not limited thereto.

[0042] Further, the annealing temperature of the annealing treatment is 100 - 150 °C.

[0043] Further, the annealing time of the annealing treatment is 20 - 60 min.

[0044] In some embodiments, the preparation method specifically includes: applying a passivation layer solution onto the surface of the perovskite layer by spin - coating and performing annealing treatment to obtain a passivation layer; wherein, the passivation layer solution includes a solute and a solvent; the solute includes any one or a combination of more than one of 2 - phenylethylamine hydrochloride, phenethylammonium bromide, thiophenylethylammonium chloride, and is not limited thereto.

[0045] Further, the solvent includes any one or a combination of more than one of isopropanol, DMF, DMSO, and is not limited thereto.

[0046] Further, the spin - coating speed used in the spin - coating method is 2000 - 4000 rpm.

[0047] Further, the spin - coating time used in the spin - coating method is 20 - 40 s.

[0048] Further, the annealing temperature of the annealing treatment is 60 to 100 °C.

[0049] Further, the annealing time of the annealing treatment is 5 to 10 min.

[0050] In some embodiments, the preparation method specifically includes: transferring the film obtained after depositing the passivation layer to a thermal evaporator, and sequentially depositing an electron transport layer, a blocking layer, and a top electrode under a vacuum of <5×10 -5 Pa.

[0051] Further, the electron transport layer includes electron transport layer C60 and / or PCBM, and the thickness of the electron transport layer is 8 to 30 nm.

[0052] Further, the blocking layer includes blocking layer BCP and / or ALD tin oxide, and the thickness of the blocking layer is 5 to 20 nm.

[0053] Further, the top electrode includes any one of top electrode Ag, top electrode Cu, and top electrode Au, and the thickness of the top electrode is 70 to 120 nm.

[0054] Among them, in some more specific implementation cases, the preparation method of the perovskite solar cell based on co-self-assembled molecule-induced in-situ interfacial polymerization includes the following steps: 1) Provide a glass substrate and a conductive glass ITO and clean them. The selected ITO has a sheet resistance of 7 - 25 Ω and a refractive index of 85 - 95%; 2) On the conductive glass, prepare a NiO x layer and then anneal it. The spin coating speed of the NiO x layer is 1500 - 3000 rpm, such as 1700 rpm, 1900 rpm, 2200 rpm, 2500 rpm, or 3000 rpm, as well as specific point values between the above point values. The annealing temperature is 150 - 200 °C, and the annealing time is 15 - 30 min; 3) On the ITO / NiO x layer, prepare a Co-SAMs layer and then anneal it. The concentration of the Co-SAMs solution is 0.4 - 0.8 mg / mL, where 1 ≤ SAM-1 / SAM-2 ≤ 3. The spin coating speed is 2000 - 4000 rpm, such as 2000 rpm, 3000 rpm, 3500 rpm, or 4000 rpm, as well as specific point values between the above point values. The annealing temperature is 100 - 150 °C, and the annealing time is 10 - 15 min; 4) During the preparation of the perovskite layer, the solutes of the precursor solution of the perovskite thin film may include formamidinium hydroiodide (FAI), methylammonium bromide (MABr), lead iodide PbI 2 , lead bromide PbBr 2 , methylammonium chloride (MACl), cesium iodide (CsI), potassium iodide (KI), and at least one of the ionic liquids of formula (IV) or formula (V) added to the perovskite precursor solution, with the required concentration being 0.05 - 0.2 mg / mL; 5) The solvent of the precursor solution of the perovskite thin film is a mixed solvent of DMF and DMSO (4:1, v:v); the three-dimensional perovskite thin film is spin-coated, and an anti-solvent is dropped during the spin-coating process; the anti-solvent is preferably any one or a combination of at least two of chlorobenzene, toluene, or anisole. The spin-coating speed is controlled in two steps. The first step is 500 - 1000 rpm, and the spin-coating time is 5 - 10 s. The second step is 3000 - 5000 rpm, and the time is 25 - 40 s. The temperature of the post-treatment is 100 - 150 °C; 6) The passivation layer is selected from at least one of 2-phenylethylamine hydrochloride, phenethylammonium bromide, or thiophenylethylammonium chloride. The solvent is a mixed solution of at least one of isopropanol, DMF, or DMSO, and the mixing ratio is 5‰ - 15‰. The spin-coating method is used, with a rotation speed of 2000 - 4000 rpm, a time of 20 - 40 s, an annealing temperature of 60 - 100 °C, and an annealing time of 5 - 10 min; 7) Subsequently, the thin film is transferred to a thermal evaporator, and an electron transport layer C60 with a thickness of 20 nm, a blocking layer BCP with a thickness of 7 nm, and a top electrode Ag with a thickness of 100 nm are deposited respectively under a high vacuum (<5×10 -5 Pa).

[0055] In the present invention, based on the dual mechanisms of Co-SAMs and in-situ polymerization, it can not only effectively passivate the defects at the perovskite buried interface, enhance the interface contact, but also significantly improve the photoelectric conversion efficiency and long-term stability of the perovskite solar cell. The present invention adopts the Co-SAMs strategy constructed by the special structure SAM-2. On the one hand, it strengthens the anchoring ability of the self-assembled molecules on the surface of the lower nickel oxide; at the same time, it combines the in-situ free radical polymerization at the interface to enhance the adhesion ability of the co-self-assembled layer to the upper perovskite buried interface, greatly improving the photoelectric conversion efficiency and long-term stability of the device.

[0056] In the present invention, through structural screening, self-assembled molecules with the SAM-2 structure (such as 11-mercaptoundecylphosphonic acid (MPA)) are introduced into self-assembled molecules with the SAM-1 structure (such as [4-(7H-dibenzocarbazol-7-yl)butyl]phosphonic acid (4PADCB)) to form a co-self-assembled molecular structure (Co-SAMs). Meanwhile, based on the free radical polymerization mechanism, an ionic liquid with a carbon-carbon double bond at the end group (such as 1-allyl-3-vinylimidazolium bis(trifluoromethanesulfonyl)imide (AVMTF 2 )) is added to the perovskite layer precursor solution. Under heating conditions, the thiol group initiates free radical polymerization of the carbon-carbon double bond, and a polymer is in-situ generated at the buried interface between the co-self-assembled layer and the perovskite layer, thereby improving the coverage rate of the SAM lower layer while enhancing the adhesion force with the perovskite buried interface, achieving better interfacial contact, suppressing interfacial non-radiative polymerization, and enabling the device to have excellent photoelectric conversion efficiency and excellent long-term stability.

[0057] The present invention is further illustrated by the following examples: According to the following examples, the present invention can be better understood. However, those skilled in the art can easily understand that the specific material ratios, process conditions and their results described in the examples are only used to illustrate the present invention, and should not and will not limit the present invention described in detail in the claims.

[0058] Unless otherwise specified, various raw materials, reaction equipment, testing equipment and testing methods used in the following examples are well-known in the art.

[0059] Example 1 1. Raw material preparation: (1) Hole transport layer (nickel oxide + co-self-assembled layer): Weigh nickel oxide NiO x (100.0 mg) and dissolve it in 500 μL of deionized water. Weigh [4-(7H-dibenzocarbazol-7-yl)butyl]phosphonic acid (4PADCB, SAM-1) 300.0 mg and 11-mercaptoundecylphosphonic acid (MPA, SAM-2) 100.0 mg respectively and dissolve them in 1 mL of absolute ethanol (concentration: 0.4 mg / mL); (2) Perovskite layer: In a nitrogen glove box, weigh formamidinium hydroiodide FAI (181.4 mg), methylammonium bromide MABr (6.3 mg), lead iodide PbI 2 (529.0 mg), and lead bromide PbBr 2(2.03 mg), methylammonium chloride MACl (68.77 mg), cesium iodide CsI (16.8 mg), and dissolve them in 800 μL of a mixed solution of DMF: DMSO with a volume ratio of 4:1. Weigh 50 mg of 1-allyl-3-vinylimidazolium bis(trifluoromethanesulfonyl)imide ionic liquid and add it to the perovskite precursor solution, stir at room temperature for 2 h and set aside.

[0060] (3) Passivation layer: Prepare a thiopheneethylammonium chloride solution with a concentration of 1.0 mg / mL, and the solvent is isopropanol.

[0061] (4) The electron transport layer, blocking layer, and electrode are C60, BCP, and Ag respectively, and all are deposited by evaporation.

[0062] 2. Implementation process: Select an ITO (sheet resistance 7 Ω, refractive index 93%) substrate, which needs to be ultrasonically treated with deionized water, isopropanol, and ethanol solution before use, and the duration is 20 min for each.

[0063] (1) Hole transport layer (nickel oxide + co-self-assembled layer): Nickel oxide layer: Prepared in air, spin-coating speed is 2000 rpm, spin-coating time is 30 s, annealing temperature is 200 °C, and annealing time is 30 min.

[0064] Co-self-assembled layer: Prepared in a glove box, spin-coating speed is 3000 rpm, spin-coating time is 30 s, annealing temperature is 120 °C, and annealing time is 10 min.

[0065] (2) Perovskite layer: Prepared in a glove box, two-step spin-coating method, the first step is 1000 rpm, spin-coating time is 10 s, the second step is 5000 rpm, spin-coating time is 40 s. 200 μL of chlorobenzene antisolvent is added dropwise at the 10th second before the end of spin-coating, annealing temperature is 120 °C, and annealing time is 30 min.

[0066] (3) Passivation layer: Prepared in a glove box, spin-coating speed is 3000 rpm, spin-coating time is 30 s, annealing temperature is 70 °C, and annealing time is 10 min (4) Electron transport layer, blocking layer, electrode: Under the condition of a vacuum of 1×10 -5 Pa, deposit C60, BCP, and Ag in sequence, and their thicknesses are 15 nm, 10 nm, and 100 nm respectively.

[0067] Example 2: The method is the same as that of Example 1, the difference is that (2-mercaptoethyl)phosphonic acid is selected to replace 11-mercaptoundecylphosphonic acid in Example 1 as SAM-2.

[0068] Example 3 The method is the same as that of Example 1, except that 1-allyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt is selected to replace the ionic liquid of 1-allyl-3-vinylimidazolium bis(trifluoromethanesulfonyl)imide salt in Example 1.

[0069] Comparative Example 1 The method is the same as that of Example 1, except that SAM-2 is missing.

[0070] Comparative Example 2 The method is the same as that of Example 1, except that tetramethylammonium bis(trifluoromethanesulfonyl)imide salt ionic liquid is selected to replace the 1-allyl-3-vinylimidazolium bis(trifluoromethanesulfonyl)imide salt ionic liquid in Example 1.

[0071] Performance characterization: Figure 1 It is a schematic cross-sectional view of the perovskite solar cell of the example; Figure 2 It is the surface roughness map of the self-assembled layer of the perovskite solar cells prepared in Example 1 and Comparative Example 1. It can be seen that Example 1 has a lower surface roughness compared with Comparative Example 1; Figure 3 It is the conductivity curve graph of the perovskite solar cell samples prepared in Example 1 and Comparative Example 1. It can be seen that Example 1 has a higher conductivity compared with Comparative Example 1, which is more conducive to accelerating the extraction of carriers; Figure 4 It is the surface morphology map of the perovskite solar cell thin films prepared in Example 1 and Comparative Example 1. It can be seen that Example 1 has larger grain sizes and a smoother surface compared with Comparative Example 1 and Comparative Example 2; Figure 5 It is the time-resolved fluorescence spectrum graph of the perovskite solar cell thin films prepared in Example 1 and Comparative Examples 1-2. It can be seen that Example 1 has a longer carrier lifetime compared with Comparative Example 2, which can better inhibit the interfacial non-radiative recombination process; Figure 6 It is the I-V curve graph of the perovskite solar cell samples prepared in Example 1 and Comparative Examples 1-2. It can be seen that Example 1 has a higher power conversion efficiency compared with Comparative Examples 1-2; Figures 7 - 8 It is the adhesion force curve graph of the perovskite solar cell thin films prepared in Example 1 and Comparative Examples 1-2. It can be seen that Example 1 has a greater interfacial adhesion force compared with Comparative Examples 1-2 and has better interfacial contact; Figure 9 It is the long-term stability curve graph of the perovskite solar cell samples prepared in Example 1 and Comparative Example 1. It can be seen that Example 1 has more excellent long-term stability compared with Comparative Example 1.

[0072] In addition, the inventors of this case also referred to the foregoing examples and conducted tests with other raw materials, process operations, and process conditions described in this specification, and all obtained relatively ideal results.

[0073] The foregoing has shown and described the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments, and what is described in the above embodiments and the specification is only to illustrate the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements fall within the scope of the present invention claimed.

Claims

1. A perovskite solar cell based on co-self-assembled molecules induced interface in-situ polymerization, characterized in that: include: A nickel oxide layer, a co-self-assembly layer, an in-situ polymer layer, a perovskite layer, a passivation layer, an electron transport layer and a top electrode are sequentially arranged on the surface of the substrate; The in-situ polymer layer is arranged between the co-self-assembly layer and the perovskite layer, the co-self-assembly layer includes co-self-assembly molecules, and the co-self-assembly molecules are formed by mixing first self-assembly molecules and second self-assembly molecules containing thiol groups at the ends; the perovskite layer precursor solution for preparing the perovskite layer includes an ionic liquid, and the cation part of the ionic liquid contains a carbon-carbon double bond end group; the in-situ polymer layer is formed by in-situ polymerization of the second self-assembly molecules and the ionic liquid; The first self-assembling molecule has a structure as shown in formula (I), and the second self-assembling molecule has a structure as shown in formula (II) and / or formula (III): Among them, 2≤ n ≤5, 3≤ x ≤12, 2≤ y ≤12.

2. The perovskite solar cell according to claim 1, characterized in that The ionic liquid has a structure as shown in formula (IV) and / or formula (V): Among them, 1≤ x1 ≤3, 1≤ x2 ≤3.

3. The perovskite solar cell according to claim 1, characterized in that: The content of the first self-assembly molecule in the co-self-assembly molecule is 50wt%~75wt%, and the content of the second self-assembly molecule is 25wt%~50wt%; and / or, the perovskite solar cell includes a substrate and a nickel oxide layer, a co-self-assembly layer, an in-situ polymer layer, a perovskite layer, a passivation layer, an electron transport layer, a blocking layer, and a top electrode arranged in sequence on the surface of the substrate.

4. The method for preparing a perovskite solar cell based on co-self-assembly molecule-induced interfacial in-situ polymerization according to any one of claims 1 to 3, characterized in that: include: providing a substrate; Furthermore, a nickel oxide layer, a co-self-assembly layer, an in-situ polymer layer, a perovskite layer, a passivation layer, an electron transport layer, a blocking layer, and a top electrode are sequentially prepared on the surface of a substrate, thereby obtaining a perovskite solar cell based on co-self-assembly molecules induced interface in-situ polymerization.

5. The preparation method according to claim 4, characterized in that: Specifically include: The substrate is cleaned, and then a nickel oxide layer is prepared on the surface of the substrate by spin coating and annealing is performed; preferably, the substrate is a transparent conductive substrate, and the transparent conductive substrate includes an ITO substrate or a FTO transparent conductive glass substrate; preferably, the spin coating speed used in the spin coating method is 1500~3000rpm; preferably, the annealing temperature of the annealing treatment is 150~200℃; preferably, the annealing time of the annealing treatment is 15~30min.

6. The preparation method according to claim 4, characterized in that: Specifically include: The first self-assembling molecule and the second self-assembling molecule are mixed to form a co-self-assembling molecule solution, and then the co-self-assembling molecule solution is applied to the surface of the nickel oxide layer by spin coating and annealing is performed to obtain a co-self-assembling layer; preferably, the concentration of the co-self-assembling molecule solution is 0.4-0.8 mg / mL, and the mass ratio of the first self-assembling molecule to the second self-assembling molecule is 1:1-3:1; preferably, the spin coating speed used in the spin coating method is 2000-4000 rpm; preferably, the annealing temperature of the annealing treatment is 100-150°C; preferably, the annealing time of the annealing treatment is 10-15 min.

7. The preparation method according to claim 4, characterized in that: Specifically include: A perovskite layer precursor solution is applied to the surface of the co-self-assembled layer by a spin coating method and annealed to obtain a perovskite layer; wherein the perovskite layer precursor solution comprises a solute and a solvent; the solute comprises any one or more combinations of formamidine hydroiodide, methylammonium bromide, lead iodide, lead bromide, methylamine hydrochloride, cesium iodide, potassium iodide and an ionic liquid; preferably, the solvent comprises a mixed solvent formed by DMF and DMSO; preferably, an anti-solvent is added during the spin coating process, and the anti-solvent comprises any one or more combinations of chlorobenzene, toluene, and anisole; preferably, the annealing temperature of the annealing treatment is 100-150°C; preferably, the annealing time of the annealing treatment is 20-60min.

8. The preparation method according to claim 4, characterized in that: Specifically include: A passivation layer solution is applied to the surface of a perovskite layer by a spin coating method and annealing treatment is performed to obtain a passivation layer; wherein the passivation layer solution comprises a solute and a solvent; the solute comprises any one or more combinations of 2-phenylethylamine hydrochloride, phenethylammonium bromide, and thiopheneethylammonium chloride; preferably, the solvent comprises any one or more combinations of isopropanol, DMF, and DMSO; preferably, the spin coating speed used in the spin coating method is 2000-4000 rpm; preferably, the annealing temperature of the annealing treatment is 60-100°C; preferably, the annealing time of the annealing treatment is 5-10 min.

9. The preparation method according to claim 4, characterized in that: Specifically include: The thin film obtained after the deposition of the passivation layer was transferred to a thermal evaporator and heated to a vacuum of <5 × 10 -5 The electron transport layer, the blocking layer and the top electrode were deposited in sequence under the condition of Pa.

10. The preparation method according to claim 9, characterized in that: The electron transport layer includes an electron transport layer C60 and / or PCBM, and the thickness of the electron transport layer is 8~30nm; and / or, the blocking layer includes a blocking layer BCP and / or ALD tin oxide, and the thickness of the blocking layer is 5~20nm; and / or, the top electrode includes any one of top electrode Ag, top electrode Cu, and top electrode Au, and the thickness of the top electrode is 70~120nm.

Images