Perovskite solar cell and method of manufacturing the same

Abstract

The application relates to a perovskite solar cell and a preparation method thereof. The perovskite solar cell comprises a conductive substrate electrode, a hole transport layer, a perovskite layer and a counter electrode which are arranged in a stack, the hole transport layer comprises a self-assembled monomolecular material and an organic additive, and the organic additive has R1 and R2, wherein R1 is an acidic group, and R2 is a nitrogen-containing group. The perovskite solar cell can improve the photoelectric conversion efficiency of the cell by adding the specific organic additive in the hole transport layer, so that the hole transport layer is in full contact with the perovskite layer and the conductive substrate electrode. In addition, the nitrogen-containing group in the organic additive can also induce the crystalline orientation of the perovskite layer and passivate the perovskite layer.

Description

Technical Field

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

[0002] Perovskite solar cells possess advantages such as high light absorption coefficient, tunable bandgap, simple fabrication process, and low cost, making them one of the most promising solar cells for application. The structure of a perovskite solar cell mainly includes a conductive substrate electrode, a hole transport layer, a perovskite layer, an electron transport layer, and a counter electrode. The hole transport layer plays a crucial role in collecting and transporting holes, thereby achieving effective separation of electrons and holes, and significantly impacting the cell's efficiency and stability.

[0003] Self-assembled monolayers (SAMs) are ordered monolayers that spontaneously adsorb and form on a solid substrate. In recent years, they have been used as hole transport layers in perovskite solar cells. Currently, the main self-assembled monolayer materials used as hole transport layers include (2-(9H-carbazole-9-yl)ethyl)phosphonic acid (2PACz) and (4-(3,6-dimethyl-9H-carbazole-9-yl)butyl)phosphonic acid (Me-4PACz). Compared to traditional hole transport materials, self-assembled monolayer materials have advantages such as high hole selectivity, high fabrication compatibility, and low parasitic absorption. Self-assembled monolayer materials typically have a structure with one hydrophilic end and one oleophilic end. During cell fabrication, the hydrophilic end reacts and bonds with the transparent conductive substrate, exposing the oleophilic end to the surface of the SAM layer and allowing it to directly contact the perovskite layer. However, the solutions used to prepare the perovskite layer usually include highly polar solvents such as DMF, DMSO, or NMP. These solvents have poor compatibility with the lipophilic groups on the surface of the SAM layer. Therefore, the perovskite solution has poor wettability on the surface of the SAM layer, and the formed perovskite layer cannot make sufficient contact with the SAM layer, which reduces the photoelectric conversion efficiency of the perovskite solar cell. Summary of the Invention

[0004] Therefore, it is necessary to provide a perovskite solar cell with high photoelectric conversion efficiency and its preparation method.

[0005] One aspect of this application provides a perovskite solar cell, the perovskite solar cell comprising a conductive substrate electrode, a hole transport layer, a perovskite layer and a counter electrode stacked together, the hole transport layer comprising a self-assembled monomolecule material and an organic additive, the organic additive having R1 and R2, wherein R1 is an acidic group and R2 is a nitrogen-containing group.

[0006] The aforementioned perovskite solar cells improve photoelectric conversion efficiency by incorporating specific organic additives into the hole transport layer, ensuring sufficient contact between the hole transport layer, the perovskite layer, and the conductive substrate electrode. Specifically, during the fabrication of the perovskite solar cell, acidic groups in the organic additive molecular chain undergo a bonding reaction with the conductive substrate electrode, effectively enhancing the bonding strength between the hole transport layer and the conductive substrate electrode. Nitrogen-containing groups in the organic additive molecular chain are exposed on the surface of the hole transport layer, and these nitrogen-containing groups possess suitable polarity, thus improving the wettability of the perovskite solution on the surface of the hole transport layer, thereby ensuring a tight bond between the perovskite layer and the hole transport layer. Furthermore, the nitrogen-containing groups can also induce the crystallization orientation of the perovskite layer and passivate it.

[0007] In some embodiments, R1 includes at least one of -COOH, -SO3H and -PO3H2.

[0008] In some embodiments, R2 includes at least one of -NH2, -N=CHNH2, -N=C(NH2)2, -N(CH3)C(NH2)=NH and -C≡N.

[0009] In some embodiments, the organic additive further includes a linking group L connecting R1 and R2, wherein L includes C1-C8 alkyl, C1-C8 heteroalkyl, and C5-C6 alkyl groups. 12 At least one of the aryl groups.

[0010] In some embodiments, the organic additive is selected from at least one of guanidinoacetic acid, ethyl guanidinosulfonate, inositol phosphate, guanidinium β-propionate, L-3-guanidinoalanine hydrochloride, 4-guanidinobutyric acid, L-arginine, p-guanidinobenzoic acid salt, 2-guanidinosuccinic acid, and (S)-(-)-2-guanidinoglutaric acid.

[0011] In some embodiments, the self-assembled monomolecule material includes at least one of compound (I) and compound (II), the structural formulas of which are as follows:

[0012]

[0013] Among them, R3, R4, R5, R6, R7, R8, R9 and R 10 Each is independently selected from at least one of -H, -CH3, -C2H5, -OCH3, -X and -NH2.

[0014] In some embodiments, the molar ratio of the organic additive to the self-assembled monomolecular material is (2-5):100.

[0015] In some embodiments, the perovskite solar cell further includes an electron transport layer disposed between the perovskite layer and the counter electrode.

[0016] Another aspect of this application provides a method for fabricating the above-mentioned perovskite solar cell, comprising the following steps:

[0017] The self-assembled monomolecule material and the organic additive are added to a solvent to prepare a mixed solution;

[0018] The mixed solution is coated onto the surface of the conductive substrate electrode to prepare the hole transport layer;

[0019] The perovskite layer is formed on the hole transport layer;

[0020] A counter electrode is formed on the perovskite layer.

[0021] In some embodiments, the concentration of the self-assembled monomolecule material in the mixed solution is 0.5 g / L to 1.5 g / L, and the concentration of the organic additive is 0.01 g / L to 0.04 g / L. Attached Figure Description

[0022] Figure 1 The image shows a comparison of the contact angles of the perovskite solution on the hole transport layer surface of Example 1 and Comparative Example 1, where a represents Example 1 and b represents Comparative Example 1.

[0023] Figure 2 The current density-voltage curves are for Examples 1, 2, 4 and 6.

[0024] Figure 3 The current density-voltage curves are for Example 1, Comparative Example 1, and Comparative Example 4. Detailed Implementation

[0025] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings. Preferred embodiments of this application are shown in the drawings. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of this application.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items. In the description of this application, "a plurality of" means at least two, such as two, three, etc., unless otherwise expressly specified.

[0027] The weights of the relevant components mentioned in the embodiments of this application can refer not only to the specific content of each component, but also to the proportional relationship between the weights of the components. Therefore, any scaling up or down of the content of the relevant components according to the embodiments of this application is within the scope disclosed in the embodiments of this application. Specifically, the weights mentioned in the embodiments of this application can be well-known units of mass in the chemical industry, such as μg, mg, g, and kg.

[0028] One embodiment of this application provides a perovskite solar cell, including a conductive substrate electrode, a hole transport layer, a perovskite layer and a counter electrode stacked together. The hole transport layer includes a self-assembled monomolecule material and an organic additive. The organic additive has R1 and R2, wherein R1 is an acidic group and R2 is a nitrogen-containing group.

[0029] Understandably, in the aforementioned hole transport layer, the self-assembled monomolecular material serves as the main component, playing a role in collecting and transporting holes. Compared to traditional hole transport materials, this material exhibits stronger hole selectivity and less parasitic absorption. It should be noted that during the preparation of the hole transport layer, the self-assembled monomolecular material can adsorb onto the surface of the conductive substrate electrode and form a self-assembled monomolecular layer (SAM layer) on the electrode surface through self-assembly. Organic additives can be dispersed within the SAM layer, thereby forming the hole transport layer.

[0030] Furthermore, the R1 group in the organic additive has a certain degree of acidity, enabling it to undergo a bonding reaction with the conductive substrate electrode, thus enhancing the bonding strength between the hole transport layer and the conductive substrate electrode. The R2 group in the organic additive is exposed on the surface of the hole transport layer. Because the R2 group has suitable polarity, it is compatible with highly polar solvents (such as N,N-dimethylformamide and dimethyl sulfoxide) used in the preparation of the perovskite layer. Therefore, during the preparation of the perovskite layer, the perovskite solution coated on the surface of the hole transport layer can fully wet the surface of the hole transport layer, improving the problem of poor wettability of the perovskite solution on the SAM layer surface. This allows for a tighter bond between the perovskite layer and the hole transport layer, while also enhancing the bonding strength between them, further improving the photoelectric conversion efficiency and stability of the battery.

[0031] In some embodiments, R1 is selected from at least one of -COOH, -SO3H, and -PO3H2. These acidic groups can react more effectively with the conductive substrate electrode, further enhancing the bonding strength between the hole transport layer and the perovskite layer. It should be noted that one molecule of the organic additive may include one or more R1 groups.

[0032] In some embodiments, R2 is selected from at least one of -NH2, -N=CHNH2, -N=C(NH2)2, -N(CH3)C(NH2)=NH, and -C≡N. These nitrogen-containing groups have suitable polarity, which can effectively improve the wettability of the perovskite solution on the hole transport layer surface and can also induce the crystallization orientation of the perovskite material, thus passivating the perovskite layer surface. It should be noted that one molecule of organic additive may include one or more R2 groups. Understandably, -N(CH3)C(NH2)=NH is a methylguanidine group, with the following structural formula:

[0033]

[0034] In some embodiments, the organic additive further includes a linking group L connecting R1 and R2, wherein L includes C1-C8 alkyl, C1-C8 heteroalkyl, and C5-C6 alkyl groups. 12 At least one of the aryl groups. When L is selected from the above-mentioned linking groups, the organic additive can have a suitable length. Therefore, when the acidic group at one end of the organic additive is adsorbed on the surface of the conductive substrate electrode, the nitrogen-containing group at the other end can still be exposed on the surface of the hole transport layer, thereby improving the wettability of the perovskite solution.

[0035] Understandably, the carbon atom in L can serve as the linking site for R1 and R2, when L is selected from C1-C8 alkyl, C1-C8 heteroalkyl, and C5-C6 alkyl groups. 12 When L is selected from aryl groups, R1 and R2 can be attached to any one of the carbon atoms in L. For example, R1 and R2 are attached to the carbon atoms at both ends of the C4 alkyl molecular chain. When L is selected from C1-C8 alkyl, C1-C8 heteroalkyl, and C5-C6 alkyl groups... 12 When there are multiple aryl groups, R1 is attached to one L group and R2 is attached to another L group. The two L groups can be directly attached or attached through other linking groups. For example, L includes ethyl and phenyl. R1 is attached to the first carbon atom of the ethyl group and R2 is attached to the first carbon atom of the phenyl group. The second carbon atom of the ethyl group is attached to the fourth carbon atom of the phenyl group.

[0036] Furthermore, when the organic additive has R1 and / or R2, the linking group L is disposed between any one of R1 and R2. For example, if a molecule of organic additive has two R1s and one R2, and the linking group L is a C4 alkyl group, then one R1 is attached to the first carbon atom of the C4 alkyl group, R2 is attached to the fourth carbon atom of the C4 alkyl group, and the other R1 may be attached to the first, second, third, or fourth carbon atom of the C4 alkyl group.

[0037] Understandably, C1 to C8 alkyl refers to alkyl groups containing 1 to 8 carbon atoms, and each time it appears, it can independently be C1 alkyl, C2 alkyl, C3 alkyl, C4 alkyl, C5 alkyl, C6 alkyl, C7 alkyl, or C8 alkyl. Suitable examples include, but are not limited to: methyl (Me, -CH3), ethyl (Et, -CH2CH3), 1-propyl (n-Pr, n-propyl, -CH2CH2CH3), 2-propyl (i-Pr, i-propyl, -CH(CH3)2), 1-butyl (n-Bu, n-butyl, -CH2CH2CH2CH3), 2-methyl-1-propyl (i-Bu, i-butyl, -CH2CH(CH3)2), 2-butyl (s-Bu, s-butyl, -CH(C H3)CH2CH3) and 2-methyl-2-propyl (t-Bu, t-butyl, -C(CH3)3), 1-pentyl (n-pentyl, -CH2CH2CH2CH2CH3), 2-pentyl (-CH(CH3)CH2CH2CH3), 3-pentyl (-CH(CH2CH3)2), 2-methyl-2-butyl (-C(CH3)2CH2CH3), 3-methyl-2-butyl (-CH(CH3)CH(CH3)2), 3-methyl-1-butyl (- CH2CH2CH(CH3)2), 2-methyl-1-butyl(-CH2CH(CH3)CH2CH3), 1-hexyl(-CH2CH2CH2CH2CH2CH3), 2-hexyl(-CH(CH3)CH2CH2CH2CH3), 3-hexyl(-CH(CH2CH3)(CH2CH2CH3)), 2-methyl-2-pentyl(-C(CH3)2CH2CH2CH3), 3-methyl-2-pentyl(-CH(CH3)CH( CH3)CH2CH3), 4-methyl-2-pentyl (-CH(CH3)CH2CH(CH3)2), 3-methyl-3-pentyl (-C(CH3)(CH2CH3)2), 2-methyl-3-pentyl (-CH(CH2CH3)CH(CH3)2), 2,3-dimethyl-2-butyl (-C(CH3)2CH(CH3)2), 3,3-dimethyl-2-butyl (-CH(CH3)C(CH3)3 and octyl (-(CH2)7CH3).

[0038] Understandably, "heteroalkyl" refers to an alkyl group in which at least one carbon atom is replaced by a non-carbon atom, which can be an N atom, O atom, S atom, etc. For example, if a carbon atom in an alkyl group that is attached to the parent nucleus is replaced by a non-carbon atom, the resulting heteroalkyl group is an alkoxy group (e.g., -OCH3, etc.), an amine (e.g., -NHCH3, -N(CH3)2, etc.), or a thioalkyl group (e.g., -SCH3). If a carbon atom in an alkyl group that is not attached to the parent nucleus is replaced by a non-carbon atom, the resulting heteroalkyl group is an alkyl ether (e.g., -CH2CH2-O-CH3, etc.), an alkylamine (e.g., -CH2NHCH3, -CH2N(CH3)2, etc.), or a thioalkyl ether (e.g., -CH2-S-CH3). If the terminal carbon atom of an alkyl group is replaced by a non-carbon atom, the resulting heteroalkyl group is a hydroxyalkyl group (e.g., -CH2CH2-OH), an aminoalkyl group (e.g., -CH2NH2), or an alkyl mercapto group (e.g., -CH2CH2-SH). Phrases containing the term, such as “C1-C8 heteroalkyl”, refer to heteroalkyl groups containing 1 to 8 carbon atoms, and each time they appear, they can be independently C1 heteroalkyl, C2 heteroalkyl, C3 heteroalkyl, C4 heteroalkyl, C5 heteroalkyl, C6 heteroalkyl, C7 heteroalkyl, or C8 heteroalkyl.

[0039] Understandably, "aryl" refers to an aromatic hydrocarbon group derived from an aromatic ring compound by removing one hydrogen atom. It can be a monocyclic aryl or a fused-ring aryl, and for polycyclic compounds, at least one must be an aromatic ring system. For example, "C5~C5..." 12 "Aryl" refers to an aryl group containing 5 to 12 carbon atoms. Each time it appears, it can independently be C5 aryl, C6 aryl, C7 aryl, C8 aryl, or C9 aryl. 10 Aryl or C 12 Aryl. Suitable examples include, but are not limited to, cyclopentyl or phenyl.

[0040] In some embodiments, the organic additive is selected from at least one of guanidinoacetic acid, ethyl guanidinosulfonate, inositol phosphate, guanidinium β-propionate, L-3-guanidinoalanine hydrochloride, 4-guanidinobutyric acid, L-arginine, p-guanidinobenzoate, 2-guanidinosuccinic acid, and (S)-(-)-2-guanidinoglutaric acid. Understandably, using a protonated organic additive with a hydrogen halide acid can protonate the nitrogen-containing group, thereby further improving the wettability of the perovskite solution on the hole transport layer surface, and the halide anion can also passivate the interface between the hole transport layer and the conductive substrate electrode, while simultaneously passivating the interface between the hole transport layer and the perovskite layer. It should be noted that ethyl guanidinosulfonate is an organic compound having the structure shown below:

[0041]

[0042] In some embodiments, the self-assembled monomolecular material includes compound (I) and compound (II), the structural formulas of which are as follows:

[0043]

[0044] Among them, R3, R4, R5, R6, R7, R8, R9 and R 10 Each compound (I) and compound (II) are independently selected from at least one of -H, -CH3, -C2H5, -OCH3, -X, and -NH2, where X is a halogen atom. Optionally, X is selected from at least one of Cl, Br, and I. By selecting compounds (I) and (II) as self-assembled monomolecule materials, the photoelectric conversion efficiency of the battery can be improved.

[0045] Optionally, the self-assembled monomolecular materials include, but are not limited to, at least one of [2-(9H-carbazole-9-yl)ethyl]phosphoric acid, [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphoric acid, [4-(3,6-dimethoxy-9H-carbazole-9-yl]butyl]phosphoric acid, [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphoric acid, and [2-(2,7-dimethoxy-9H-carbazole-9-yl)ethyl]phosphoric acid.

[0046] Understandably, [2-(9H-carbazole-9-yl)ethyl]phosphoric acid can also be called 2PACz, [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphoric acid can also be called 3,6-Me-4PACz, [4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphoric acid can also be called 3,6-MeO-4PACz, [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphoric acid can also be called 3,6-MeO-2PACz, and [2-(2,7-dimethoxy-9H-carbazole-9-yl)ethyl]phosphoric acid can be called 2,7-MeO-2PACz.

[0047] In some embodiments, the molar ratio of the organic additive to the self-assembled monomolecule material is (2–5):100. When the molar ratio is within this range, the wettability of the perovskite solution on its surface can be improved while ensuring the hole transport efficiency of the hole transport layer. Optionally, the molar ratio of the organic additive to the self-assembled monomolecule material can be 2:100, 2.5:100, 3:100, 3.5:100, 4:100, 4.5:100, or 5:100, and other suitable selections can be made within the range of (2–5):100.

[0048] In some embodiments, the material of the conductive substrate electrode may be, but is not limited to, at least one of fluorine-doped tin oxide (FTO), indium-doped tin oxide (ITO), aluminum-doped zinc oxide (AZO), boron-doped zinc oxide (BZO), and indium-doped zinc oxide (IZO).

[0049] In some embodiments, the perovskite layer is made of perovskite with the structural formula ABX3, wherein A comprises an organic cation, an inorganic cation, or a mixture of organic and inorganic cations, and B comprises an organic cation, an inorganic cation, or a mixture of organic and inorganic cations.

[0050] In the above embodiments, perovskite materials with corresponding ions can be selected to prepare the perovskite layer according to actual needs. Optionally, A includes CH3NH3. + CH(NH2)2 + Li + Na + K + 、Rb + and Cs + At least one of them, B includes Pb 2+ Sn 2 + Be 2+ Mg 2+ Ca 2+ 、Sr 2+ Ba 2+ Zn 2+ 、Ge 2+ Fe 2+ Co 2+ and Ni 2+ At least one of them, X includes F - Cl - ,Br - and I - At least one of them.

[0051] In some embodiments, perovskite can be Cs 0.35 FA 0.65 PbI 1.8 Br 1.2 Cs 0.05 MA 0.10 FA 0.85 PbI3, where FA is formamidinium ion and MA is methylamine ion.

[0052] In some embodiments, the counter electrode comprises a metal electrode. Optionally, the metal electrode includes, but is not limited to, at least one of Ag, Cu, C, and Au. The material of the counter electrode may also be at least one of ITO, AZO, BZO, IZO, and IWO.

[0053] In some embodiments, the perovskite solar cell further includes an electron transport layer disposed between the perovskite layer and the counter electrode. Optionally, the composition of the electron transport layer may be an electron transport material commonly used in the art, including but not limited to at least one of [6,6]-phenyl-C61-butyrate (PC61BM), [6,6]-phenyl-C71-butyrate (PC71BM), fullerene C60, fullerene C70, tin dioxide, and zinc oxide.

[0054] In some embodiments, an interface modification layer is further disposed between the electron transport layer and the metal electrode. The efficiency of the perovskite solar cell can be further improved by providing an interface modification layer. Optionally, the interface modification layer can be made of commonly used interface modification materials in the art, including but not limited to 2,9-dimethyl-4,7-biphenyl-1,10-o-phenanthroline (BCP).

[0055] The aforementioned perovskite solar cells improve photoelectric conversion efficiency by incorporating specific organic additives into the hole transport layer, ensuring sufficient contact between the hole transport layer, the perovskite layer, and the conductive substrate electrode. Specifically, during the fabrication of the perovskite solar cell, acidic groups in the organic additive molecular chain undergo a bonding reaction with the conductive substrate electrode, effectively enhancing the bonding strength between the hole transport layer and the conductive substrate electrode. Nitrogen-containing groups in the organic additive molecular chain are exposed on the surface of the hole transport layer, and these nitrogen-containing groups possess suitable polarity, thus improving the wettability of the perovskite solution on the surface of the hole transport layer, thereby ensuring a tight bond between the perovskite layer and the hole transport layer. Furthermore, the nitrogen-containing groups can also induce the crystallization orientation of the perovskite layer and passivate it.

[0056] Another embodiment of this application provides a method for preparing the above-mentioned perovskite solar cell, comprising the following steps:

[0057] S10. Add the self-assembled single-molecule material and organic additives to the solvent to prepare a mixed solution;

[0058] S20. The mixed solution is coated on the surface of the conductive substrate electrode to prepare a hole transport layer;

[0059] S30. A perovskite layer is formed on the hole transport layer;

[0060] S40, Form a counter electrode on the perovskite layer.

[0061] Understandably, the preparation method of each layer in the process of preparing perovskite solar cells is not limited. For example, the preparation method can be chemical vapor deposition, physical epitaxial growth, electrochemical deposition, thermal evaporation, atomic layer deposition, magnetron sputtering, spin coating of precursor liquid, slot coating of precursor liquid, blade coating of precursor liquid, and mechanical pressing.

[0062] In some embodiments, the concentration of the self-assembled monomolecule material in the mixed solution is 0.5 g / L to 1.5 g / L, and the concentration of the organic additive is 0.01 g / L to 0.04 g / L. Optionally, the concentration of the self-assembled monomolecule material can be 0.5 g / L, 0.6 g / L, 0.7 g / L, 0.8 g / L, 0.9 g / L, 1.0 g / L, 1.1 g / L, 1.2 g / L, 1.3 g / L, 1.4 g / L, or 1.5 g / L; and the concentration of the organic additive can be 0.01 g / L, 0.015 g / L, 0.02 g / L, 0.025 g / L, 0.03 g / L, 0.035 g / L, or 0.04 g / L. Understandably, the concentration of the self-assembled monomolecule material can be selected from 0.5 g / L to 1.5 g / L, and the concentration of the organic additive can be selected from 0.01 g / L to 0.04 g / L.

[0063] In some embodiments, step S40 includes the following steps:

[0064] S401. An electron transport layer is prepared on the surface of the perovskite layer;

[0065] S402. Prepare a counter electrode on the surface of the electron transport layer.

[0066] In some embodiments, the following steps are included after step S401 and before step S402:

[0067] An interface modification layer is prepared on the electron transport layer.

[0068] The following are specific examples.

[0069] Example 1

[0070] The ITO glass substrate was cleaned sequentially with dish soap, water, acetone, and isopropanol using ultrasonic cleaning for 20 minutes each time. The cleaned ITO glass substrate was then immersed in isopropanol for storage.

[0071] Remove the ITO glass substrate, dry it with a nitrogen gun, and treat it in plasma cleaning for 3 minutes to improve wettability.

[0072] A mixed solution was prepared by adding (2-(9H-carbazole-9-yl)ethyl)phosphoric acid and inositol phosphate to methanol. The concentration of (2-(9H-carbazole-9-yl)ethyl)phosphoric acid in the mixed solution was 0.8 g / L, and the concentration of inositol phosphate was 0.031 g / L, meaning the molar ratio of inositol phosphate to (2-(9H-carbazole-9-yl)ethyl)phosphoric acid in the mixed solution was 5:100. The mixed solution was dynamically spin-coated onto an ITO glass substrate at a speed of 4000 rpm for 40 s. Subsequently, it was annealed at 90°C for 10 min to obtain a hole transport layer.

[0073] It will be composed of Cs 0.05 MA 0.10 FA 0.85 PbI3 perovskite crystals were added to a mixed solution of N,N-dimethylformamide and dimethyl sulfoxide to obtain a perovskite solution. The perovskite concentration in the solution was 1.5 mol / L, and the volume ratio of N,N-dimethylformamide to dimethyl sulfoxide was 4:1. The perovskite solution was spin-coated onto the surface of a hole transport layer at a speed of 4000 r / min for 50 s, with chlorobenzene added dropwise as an anti-solvent during the spin-coating process. Subsequently, the solution was annealed at 110 °C for 15 min to obtain the perovskite layer.

[0074] Fullerene C60, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline, and metallic silver were sequentially vacuum-deposited onto the surface of the perovskite layer to obtain an electron transport layer with a thickness of 30 nm, an interface modification layer with a thickness of 5 nm, and a metal electrode with a thickness of 100 nm, respectively. After fabrication, a perovskite solar cell was obtained.

[0075] Example 2

[0076] The preparation method of Example 2 is basically the same as that of Example 1, except that an equimolar amount of (S)-(-)-2-guanidinoglutaric acid is used instead of inositol phosphate.

[0077] Example 3

[0078] The preparation method of Example 3 is basically the same as that of Example 1, except that equimolar amounts of 4-guanidinobutyric acid are used instead of inositol phosphate.

[0079] Example 4

[0080] The preparation method of Example 4 is basically the same as that of Example 1, except that an equimolar amount of ethyl guanidine sulfonate is used instead of inositol phosphate.

[0081] Example 5

[0082] The preparation method of Example 5 is basically the same as that of Example 1, except that equimolar amounts of 4-aminobutyric acid are used instead of inositol phosphate.

[0083] Example 6

[0084] The preparation method of Example 6 is basically the same as that of Example 1, except that an equimolar amount of guanidinophenethyl phosphoric acid is used instead of inositol phosphate.

[0085] Example 7

[0086] The preparation method of Example 7 is basically the same as that of Example 1, except that equimolar amounts of 4-cyanobutyric acid are used instead of inositol phosphate.

[0087] Example 8

[0088] The preparation method of Example 8 is basically the same as that of Example 1, except that an equimolar amount of guanidinyl benzoate salt is used instead of inositol phosphate.

[0089] Example 9

[0090] The preparation method of Example 9 is basically the same as that of Example 1, except that the concentration of inositol phosphate is 0.047 g / L, that is, in the mixed solution, the molar ratio of inositol phosphate to (2-(9H-carbazole-9-yl)ethyl)phosphoric acid is 7.5:100.

[0091] Comparative Example 1

[0092] The preparation method of Comparative Example 1 is basically the same as that of Example 1, except that inositol phosphate is not added when preparing the hole transport layer.

[0093] Comparative Example 2

[0094] The preparation method of Comparative Example 2 is basically the same as that of Example 1, except that an equimolar amount of ethyl phosphoric acid is used instead of inositol phosphate.

[0095] Comparative Example 3

[0096] The preparation method of Comparative Example 3 is basically the same as that of Example 1, except that an equimolar amount of 1-ethylguanidine is used instead of inositol phosphate.

[0097] Comparative Example 4

[0098] The preparation method of Comparative Example 4 is basically the same as that of Example 1, except that: no inositol phosphate is added when preparing the hole transport layer, and an equal amount of inositol phosphate is added to the perovskite solution, that is, Comparative Example 4 is a comparative example of inositol phosphate doping.

[0099] The composition of the organic additives in the preparation methods of Examples 1-9 and Comparative Examples 1-4 is shown in Table 1. It should be noted that the difference between Example 9 and Example 1 is the amount of inositol phosphate added.

[0100] The contact angles of the perovskite solutions of Example 1 and Comparative Example 1 on the hole transport layer surface were tested using standard testing methods, and the results are as follows: Figure 1 As shown, a is Example 1 and b is Comparative Example 1. Figure 1 It can be seen that the contact angle of the perovskite solution in Example 1 on the surface of the hole transport layer is significantly smaller than that in Comparative Example 1, indicating that the organic additive of this application can improve the wettability of the perovskite solution on the surface of the hole transport layer, thereby enabling sufficient contact between the hole transport layer and the perovskite layer, and thus achieving the goal of improving the photoelectric conversion efficiency of the battery. It should be noted that... Figure 1 The dotted lines in the image are measurement lines automatically generated by the testing instrument to obtain contact angle data. They cannot be deleted, therefore they are presented as lines of varying gray levels. Figure 1 middle.

[0101] The photoelectric conversion efficiency was obtained by testing the current density-voltage curves of the perovskite solar cells in each embodiment and comparative example. The specific test conditions are as follows: at 100 mW / cm². 2 The current density-voltage curve of the battery was tested using a Keithley 2400 source meter under standard sunlight intensity. The test results are shown in Table 1 below.

[0102] Table 1

[0103]

[0104]

[0105] As shown in Table 1 above, the perovskite solar cells of Examples 1-8 exhibit good performance, with Example 1 showing the best open-circuit voltage (V0). OC The voltage is 1.13V, and the short-circuit current density (J) is... SC The value is 25.41 mA / cm. 2 The fill factor (FF) was 81.31%, and the power conversion efficiency (PCE) reached 23.37%. Compared with Example 1, the battery performance of Example 9 deteriorated. This is because Example 9 added more inositol phosphate, which relatively reduced the content of (2-(9H-carbazole-9-yl)ethyl)phosphoric acid in the hole transport layer. This resulted in a lower coverage ratio of [2-(9H-carbazole-9-yl)ethyl]phosphoric acid on the ITO glass surface, thereby reducing the efficiency of hole collection and transport in the hole transport layer and further affecting the battery performance.

[0106] The organic additive in Comparative Example 2 does not contain nitrogen-containing groups, and the organic additive in Comparative Example 3 does not contain acidic groups. Compared with Example 1, their photoelectric performance decreased, indicating that this application improves battery performance by using organic additives with both acidic and nitrogen-containing groups, thereby simultaneously improving the contact between the hole transport layer and the perovskite layer and the conductive substrate electrode. In Comparative Example 4, inositol phosphate was added to the perovskite layer, and its PCE was lower than that of Example 1. This indicates that by adding organic additives to the hole transport layer, this application can more effectively improve the wettability of the perovskite solution in the hole transport layer, allowing for sufficient contact between the hole transport layer and the perovskite layer.

[0107] Figure 2 The current density-voltage curves for Examples 1, 2, 4, and 6 are provided by [the relevant authority / organization]. Figure 2 It can be seen that, compared with the other three embodiments, Example 1, which uses inositol phosphate as an organic additive, has a higher open-circuit voltage and short-circuit current density. Figure 3 The current density-voltage curves for Example 1, Comparative Example 1, and Comparative Example 4 are provided by [the relevant authority / organization]. Figure 3 The comparison shows that in Example 1, adding an appropriate amount of inositol phosphate as an organic additive to the perovskite layer can significantly improve the open-circuit voltage and short-circuit current density of the battery.

[0108] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0109] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A perovskite solar cell, characterized in that, The perovskite solar cell includes a conductive substrate electrode, a hole transport layer, a perovskite layer and a counter electrode stacked together. The hole transport layer includes a self-assembled monomolecule material and an organic additive. The organic additive has R1 and R2, wherein R1 is an acidic group and R2 is a nitrogen-containing group. R1 includes at least one of -COOH, -SO3H and -PO3H2; R2 includes at least one of -NH2, -N=CHNH2, -N=C(NH2)2, -N(CH3)C(NH2)=NH and -C≡N; The self-assembled monomolecular material includes at least one of compound (I) and compound (II), and the structural formulas of compound (I) and compound (II) are as follows: ， Among them, R3, R4, R5, R6, R7, R8, R9 and R 10 Each is independently selected from at least one of -H, -CH3, -C2H5, -OCH3, -X and -NH2, where X is a halogen atom.

2. The perovskite solar cell as described in claim 1, characterized in that, The organic additive further includes a linking group L connecting R1 and R2, wherein L includes C1-C8 alkyl, C1-C8 heteroalkyl, and C5-C6 alkyl groups. 12 At least one of the aryl groups.

3. The perovskite solar cell according to claim 1, characterized in that, The organic additives include at least one of guanidinoacetic acid, ethyl guanidinosulfonate, inositol phosphate, guanidinium β-propionate, L-3-guanidinoalanine hydrochloride, 4-guanidinobutyric acid, L-arginine, p-guanidinobenzoic acid salt, 2-guanidinosuccinic acid, and (S)-(-)-2-guanidinoglutaric acid.

4. The perovskite solar cell according to claim 1, characterized in that, The molar ratio of the organic additive to the self-assembled monomolecule material is (2~5):

100.

5. The perovskite solar cell as described in claim 1, characterized in that, The perovskite solar cell further includes an electron transport layer disposed between the perovskite layer and the counter electrode.

6. The method for preparing a perovskite solar cell according to any one of claims 1 to 5, characterized in that, Includes the following steps: The self-assembled monomolecule material and the organic additive are added to a solvent to prepare a mixed solution; The mixed solution is coated onto the surface of the conductive substrate electrode to prepare the hole transport layer; The perovskite layer is formed on the hole transport layer; A counter electrode is formed on the perovskite layer.

7. The method for preparing a perovskite solar cell as described in claim 6, characterized in that, In the mixed solution, the concentration of the self-assembled monomolecular material is 0.5 g / L to 1.5 g / L, and the concentration of the organic additive is 0.01 g / L to 0.04 g / L.

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