Preparation method of self-assembled monomolecular layer, self-assembled monomolecular layer and perovskite solar cell

Abstract

The invention discloses a preparation method of a self-assembled monomolecular layer. The preparation method comprises the following steps: carrying out hydroxylation treatment on the surface of a conductive glass substrate; the preparation method comprises the following steps: carrying out vapor deposition on a hydroxylated conductive glass substrate through a vapor-phase precursor containing amphiphilic fluorosilane molecules F13C6H4SiCl3-Th-CHO to form a uniform SAM layer on the surface of the conductive glass substrate, and carrying out thermocuring treatment to form a stable and ordered SAM layer on the surface of the conductive glass substrate. The self-assembled monomolecular layer is prepared by the preparation method of the self-assembled monomolecular layer. According to the perovskite solar cell, a perovskite layer, a hole transport layer and an electrode are sequentially deposited on the SAM layer on the surface of the conductive glass substrate. According to the preparation method, the designed and synthesized amphiphilic cross-linked SAM molecules are matched with the electric field assisted vapor deposition and thermocuring steps to prepare the self-assembled monomolecular layer with high density, strong interface bonding force and low water vapor invasion, the comprehensive performance is obviously superior to that of a traditional SAM layer preparation method, and the stability of a perovskite assembly is improved.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic technology, specifically to perovskite solar cells, and more particularly to a method for preparing a self-assembled monolayer, the self-assembled monolayer, and a perovskite solar cell. Background Technology

[0002] In recent years, perovskite solar cells (PSCs) have become an important direction for next-generation photovoltaic technology due to their advantages such as high photoelectric conversion efficiency, low cost, and solution-processability. Their laboratory efficiency has exceeded 26%, approaching that of crystalline silicon solar cells. However, the commercialization of perovskite cells is still limited by stability issues, with interfacial degradation considered one of the main factors leading to performance degradation.

[0003] To improve interface stability, self-assembled monolayers (SAMs) are widely used for interface modification between perovskites and electrodes or transport layers. SAMs form covalent bonds with the substrate through chemical anchoring groups, which can effectively passivate interface defects, regulate energy level matching, and suppress charge recombination, thereby significantly improving device efficiency and stability.

[0004] Existing methods for preparing SAM layers mainly include solution immersion, spin coating, and conventional vapor deposition. Conventional methods have the following problems: 1. Poor film uniformity: The solution immersion method is limited by the difference in solvent polarity and surface energy, which easily leads to the formation of molecular clusters, resulting in a coverage rate of less than 70%. 2. Low degree of order: Self-assembly without external field assistance relies on intermolecular forces, resulting in disordered arrangement and affecting charge transport; 3. Poor mechanical strength and stability: It is prone to desorption or decomposition under humid heat or sunlight; 4. Insufficient controllability in preparation: Solvent residues and batch variations make industrialization difficult. Summary of the Invention

[0005] The technical problem to be solved by this invention is: to address the poor performance of SAM layers in existing technologies, this invention provides a method for preparing a self-assembled monolayer, a self-assembled monolayer, and a perovskite solar cell. It utilizes a designed and synthesized amphiphilic cross-linked SAM molecule, combined with electric field-assisted vapor deposition and thermal curing steps, to obtain a self-assembled monolayer with high density, strong interfacial bonding, and low water vapor intrusion. Its overall performance is significantly superior to traditional SAM layer preparation methods, improving the stability of perovskite modules.

[0006] The technical solution adopted by this invention to solve its technical problem is: a method for preparing a self-assembled monolayer, comprising the following steps: S1. Substrate pretreatment: The surface of the conductive glass substrate is subjected to hydroxylation treatment; S2. Electric Field Assisted Vapor Deposition: The conductive glass substrate obtained in step S1 is placed in an electric field assisted vapor deposition apparatus, and amphiphilic fluorosilane molecules F are transported into it. 13 A vapor-phase precursor of C6H4SiCl3-Th-CHO is used for vapor deposition to form a uniform SAM layer on the surface of a conductive glass substrate. S3. Thermal curing: The conductive glass substrate obtained in step S3 is thermally cured to form a stable and ordered SAM layer on the surface of the conductive glass substrate. The SAM layer is a self-assembled monolayer.

[0007] The method for preparing self-assembled monolayers of the present invention can improve the adhesion and stability of self-assembled monolayers, and has good structural rigidity and good thermal stability. It also improves interfacial wettability and energy level matching. The overall performance of the prepared SAM layer is significantly better than that of SAM layers prepared by traditional SAM layer preparation methods.

[0008] Furthermore, in step S1, the conductive glass substrate is FTO or ITO, and the surface of the conductive glass substrate is subjected to hydroxylation treatment to form a hydroxylated structure on the surface of the conductive glass substrate.

[0009] Furthermore, in step S2, the trichlorosilyl SiCl3- undergoes a condensation reaction with the hydroxylated structure of the conductive glass substrate after hydrolysis to form Si-OM bonds.

[0010] Furthermore, in step S2, the conductive glass substrate is placed in an electric field-assisted vapor deposition apparatus and deposited for 30-60 minutes under conditions of 50-100 Pa and 70-90 °C, with a vertical electric field of 5-10 V / cm applied.

[0011] Furthermore, in S3, the SAM layer thickness is 2-5 nm, the SAM layer coverage on the conductive glass substrate is >98%, the contact angle of the SAM layer is 110±5°, the surface roughness Rq of the SAM layer is <1 nm, and the water vapor transmission rate of the SAM layer is less than 10. -6 g / m 2 / day, the mechanical strength of the SAM layer is >30MPa.

[0012] Furthermore, the temperature for heat curing in S3 is 80-90℃, and the time is 10-30 minutes.

[0013] Furthermore, the SAM molecules in the SAM layer are composed of anchoring groups, linking groups, and terminal groups.

[0014] Furthermore, the anchoring group is a trichlorosilyl SiCl3- forming a Si-OM bond with the conductive oxide substrate, the linking group is the molecular backbone, and the linking group is a highly fluorinated aromatic chain F. 13C6H4, wherein the terminal group is a thiophene-aldehyde Th-CHO group.

[0015] The technical solution adopted by the present invention to solve its technical problem is: a self-assembled monolayer, wherein the self-assembled monolayer is prepared by the above-mentioned method for preparing a self-assembled monolayer.

[0016] The technical solution adopted by the present invention to solve its technical problem is: a perovskite solar cell, wherein a perovskite layer, a hole transport layer and an electrode are sequentially deposited on the SAM layer on the surface of the above-mentioned conductive glass substrate to obtain a perovskite solar cell.

[0017] Compared with the prior art, the beneficial effects of the present invention are: 1. The present invention provides a method for preparing a self-assembled monolayer, a self-assembled monolayer, and a perovskite solar cell. The method improves the molecular arrangement order and coverage through electric field induction, enhances mechanical strength and water resistance through thermosetting, and improves interfacial wettability and energy level matching through amphiphilic molecular structure, thereby significantly improving the performance of the SAM layer and the perovskite solar cell.

[0018] 2. The present invention provides a method for preparing a self-assembled monolayer, a self-assembled monolayer, and a perovskite solar cell. The anchoring group improves adhesion and enhances stability, while the linking group serves as a molecular backbone, providing a hydrophobic barrier and structural rigidity. The highly fluorinated SAM segments have extremely strong hydrophobicity, reducing water vapor permeability to an extremely low level. Attached Figure Description

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0020] Figure 1 This is a schematic flowchart of the method for preparing a self-assembled monolayer according to the present invention. Detailed Implementation

[0021] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the invention, and therefore only show the components relevant to the invention.

[0022] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, features defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0023] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0024] like Figure 1 As shown, a method for preparing a self-assembled monolayer includes the following steps: S1. Substrate pretreatment: The conductive glass substrate is FTO or ITO. The surface of the conductive glass substrate is subjected to hydroxylation treatment to form an M-OH hydroxylated structure on the surface of the conductive glass substrate, where M is Sn or In.

[0025] S2. Electric Field Assisted Vapor Deposition: The conductive glass substrate obtained in step S1 is placed in an electric field assisted vapor deposition apparatus, and amphiphilic fluorosilane molecules F are transported into it. 13 A gas-phase precursor of C6H4SiCl3-Th-CHO was deposited at 50-100 Pa and 70-90 °C for 30-60 minutes under a vertical electric field of 5-10 V / cm, perpendicular to the substrate. The electrode spacing was 5 cm. The electric field caused the molecular heads to adsorb and arrange themselves in an orderly manner, thus forming a uniform SAM layer on the conductive glass substrate surface. The trichlorosilyl SiCl3- group in the amphiphilic fluorosilane molecule undergoes hydrolysis and condenses with the hydroxylated structure of the conductive glass substrate to form Si-OM bonds.

[0026] S3. Thermal Curing: The conductive glass substrate obtained in step S3 is thermally cured at a temperature of 80-90℃ for 10-30 minutes, forming a stable and ordered SAM layer on the surface of the conductive glass substrate. The SAM layer is a self-assembled monolayer. The SAM layer thickness is 2-5 nm, the coverage of the SAM layer on the conductive glass substrate is >98%, the contact angle of the SAM layer is 110±5°, the surface roughness Rq of the SAM layer is <1 nm, and the water vapor transmission rate of the SAM layer is less than 10%. -6 g / m 2 / day, the mechanical strength of the SAM layer is >30MPa.

[0027] Specifically, the SAM molecules in the SAM layer consist of anchoring groups, linking groups, and terminal groups. The anchoring groups are trichlorosilyl SiCl3-, which form Si-OM bonds with the conductive oxide substrate (FTO or ITO), improving adhesion and enhancing stability.

[0028] Specifically, the linking group is a highly fluorinated aromatic chain F. 13 C6H4 provides a hydrophobic barrier and structural rigidity. The highly fluorinated SAM segments exhibit extremely strong hydrophobicity, reducing water vapor permeability to a very low level. Simultaneously, the linking groups act as the molecular backbone, providing structural rigidity and good thermal stability.

[0029] Specifically, the terminal group is a thiophene-aldehyde (Th-CHO) group. The thiophene-aldehyde (Th-CHO) group has perovskite-philic properties, used to regulate energy level matching and passivate interfacial defects. Its large dipole moment is key to achieving directional adsorption and ordered arrangement of molecules in electric field-assisted vapor deposition.

[0030] A self-assembled monolayer is prepared by the above-described method for preparing a self-assembled monolayer.

[0031] A perovskite solar cell is fabricated by sequentially depositing a perovskite layer, a hole transport layer, and an electrode on a SAM layer on the surface of a conductive glass substrate.

[0032] Example 1: The surface of an ITO conductive glass substrate was treated with oxygen plasma (50W, 30 seconds) to form an M-OH hydroxylated structure on the surface of the conductive glass substrate.

[0033] S2. Electric Field Assisted Vapor Deposition: The conductive glass substrate obtained in step S1 is placed in an electric field assisted vapor deposition apparatus, and amphiphilic fluorosilane molecules F are transported into it. 13The gaseous precursor of C6H4SiCl3-Th-CHO was deposited at 50 Pa and 85 °C for 30-60 minutes with a vertical electric field of 8 V / cm applied. During the deposition process, the direction of the electric field was perpendicular to the substrate, and the electrode spacing was 5 cm. The electric field caused the molecular heads to be oriented and adsorbed in an orderly manner, thus forming a uniform SAM layer on the surface of the conductive glass substrate.

[0034] S3. The conductive glass substrate obtained in step S3 is thermally cured at a temperature of 85°C for 10 minutes to form a stable and ordered SAM layer on the surface of the conductive glass substrate.

[0035] Performance characterization results: SAM layer thickness: 3.4 nm (elliptic polarimeter test), contact angle: 112°, cell performance: PCE=25.8%, FF=83.2%, Voc=1.16V, Jsc=24.3 mA / cm 2 Damp heat stability: Efficiency degradation of <12% after 2000 hours at 85℃ / 85%RH.

[0036] The SAM layer performance is balanced in Example 1.

[0037] Example 2 differs from Example 1 in that a vertical electric field of 5V / cm, a pressure of 50Pa, a deposition time of 30min, a curing temperature of 90℃, and a curing time of 20min are applied. This SAM layer remains effective even under low electric fields, verifying the applicability of low electric fields to FTO substrates.

[0038] Example 3 differs from Example 2 in that a vertical electric field of 10 V / cm, a pressure of 50 Pa, deposition time of 30 min, curing temperature of 85 °C, and curing time of 30 min are applied. This SAM layer exhibits the best stability, verifying the excellent stability achieved with a high electric field and thorough curing. In Comparative Example 1, a SAM layer was prepared using a conventional solution immersion method (toluene solution). SAM molecules were dissolved in toluene, and the ITO substrate was immersed for 30 minutes and then air-dried. The SAM layer had a coverage of 65%, contained molecular clusters, had a contact angle of 95°, a PCE of 22.1%, and exhibited an efficiency decay of >30% after 1000 hours of damp heat testing, with poor film-forming properties.

[0039] Comparative Example 2: Non-electric field assisted vapor deposition, using the same SAM molecules, deposited under non-electric field conditions. The SAM layer has low orderliness, 85% coverage, 102° contact angle, PCE=23.5%, efficiency decay of >20% after 1000 hours of damp heat testing, low crosslinking density after thermosetting, disordered molecular arrangement, and poor water resistance.

[0040] Comparative Example 3: No thermal crosslinking; the SAM layer was deposited but not thermally cured, and was allowed to air dry. The SAM layer exhibited poor mechanical strength, with a SAM coverage of 92%, a contact angle of 106°, a PCE of 23.9%, and delamination after 500 hours of damp heat testing. The efficiency decreased by more than 25%, indicating insufficient mechanical strength.

[0041] The parameters of Example 1, Example 2, Example 3, Comparative Example 1, Comparative Example 2, and Comparative Example 3 are compared in the table below.

[0042]

[0043] In summary, the self-assembled monolayer preparation method, self-assembled monolayer, and perovskite solar cell of this invention utilize a designed and synthesized amphiphilic cross-linked SAM molecule, combined with electric field-assisted vapor deposition and thermal curing steps, to obtain a self-assembled monolayer with high density, strong interfacial bonding, and low water vapor intrusion. The overall performance is significantly better than that of traditional SAM layer preparation methods, thus improving the stability of perovskite modules.

[0044] The above description is based on the preferred embodiments of the present invention. Through the above description, those skilled in the art can make various changes and modifications without departing from the technical concept of the present invention. The technical scope of the present invention is not limited to the contents of the specification, but must be determined by the scope of the claims.

Claims

1. A method for preparing a self-assembled monolayer, characterized in that, Includes the following steps: S1. Substrate pretreatment: The surface of the conductive glass substrate is subjected to hydroxylation treatment; S2. Electric Field Assisted Vapor Deposition: The conductive glass substrate obtained in step S1 is placed in an electric field assisted vapor deposition apparatus, and amphiphilic fluorosilane molecules F are transported into it. 13 A vapor-phase precursor of C6H4SiCl3-Th-CHO is used for vapor deposition to form a uniform SAM layer on the surface of a conductive glass substrate. S3. Thermal curing: The conductive glass substrate obtained in step S3 is thermally cured to form a stable and ordered SAM layer on the surface of the conductive glass substrate. The SAM layer is a self-assembled monolayer.

2. The method for preparing a self-assembled monolayer according to claim 1, characterized in that, In step S1, the conductive glass substrate is FTO or ITO, and the surface of the conductive glass substrate is subjected to hydroxylation treatment to form a hydroxylated structure on the surface of the conductive glass substrate.

3. The method for preparing a self-assembled monolayer according to claim 2, characterized in that, In step S2, trichlorosilyl SiCl3- undergoes a condensation reaction with the hydroxylated structure of the conductive glass substrate after hydrolysis, forming Si-OM bonds.

4. The method for preparing a self-assembled monolayer according to claim 3, characterized in that, In step S2, the conductive glass substrate is placed in an electric field-assisted vapor deposition apparatus and deposited for 30-60 minutes at 50-100 Pa and 70-90 °C, with a vertical electric field of 5-10 V / cm applied.

5. The method for preparing a self-assembled monolayer according to claim 1, characterized in that, In S3, the SAM layer thickness is 2-5 nm, the SAM layer coverage on the conductive glass substrate is >98%, the contact angle of the SAM layer is 110±5°, the surface roughness Rq of the SAM layer is <1 nm, and the water vapor transmission rate of the SAM layer is less than 10%. -6 g / m 2 / day, the mechanical strength of the SAM layer is >30MPa.

6. The method for preparing a self-assembled monolayer according to claim 5, characterized in that, The temperature for heat curing in S3 is 80-90℃, and the time is 10-30 minutes.

7. The method for preparing a self-assembled monolayer according to claim 1, characterized in that, The SAM molecules in the SAM layer consist of anchoring groups, linking groups, and terminal groups.

8. The method for preparing a self-assembled monolayer according to claim 2, characterized in that, The anchoring group is a trichlorosilyl SiCl3- that forms a Si-OM bond with the conductive oxide substrate; the linking group is the molecular backbone; and the linking group is a highly fluorinated aromatic chain F. 13 C6H4, wherein the terminal group is a thiophene-aldehyde Th-CHO group.

9. A self-assembled monolayer, characterized in that, The self-assembled monolayer is prepared by the method for preparing a self-assembled monolayer according to any one of claims 1-8.

10. A perovskite solar cell, characterized in that, A perovskite layer, a hole transport layer, and an electrode are sequentially deposited on the SAM layer on the surface of the conductive glass substrate as described in claim 9 to obtain a perovskite solar cell.

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