Nanosheet-resin composite ultraviolet curing perovskite battery and preparation method thereof

Abstract

The invention relates to a nanosheet-resin composite ultraviolet curing perovskite battery and a preparation method thereof. The perovskite solar cell comprises a conductive substrate, a hole transport layer, a perovskite light absorption layer, a nanosheet-resin composite modification layer, an electron transport layer and an electrode which are arranged in sequence, the single-layer nanosheet-epoxy acrylate composite modification layer comprises a single-layer nanosheet and epoxy acrylate. According to the invention, a single-layer nanosheet and epoxy acrylate are blended for the first time, and an integrated perovskite layer in-situ packaging modification layer with conductive, water vapor barrier and mechanical enhancement functions is formed through an ultraviolet in-situ curing process, so that deposition-packaging can be completed synchronously. According to the scheme, the problems of thermal / solvent damage and interface stress caused by traditional post-packaging are solved, and the humidity and thermal cycling stability of the device are remarkably improved.

Description

Technical Field

[0001] This invention belongs to the field of perovskite solar cells, specifically relating to a nanosheet-resin composite UV-cured perovskite solar cell and its preparation method, particularly a perovskite solar cell based on an MXene monolayer / epoxy acrylate UV in-situ cured composite modification layer and its preparation method. Background Technology

[0002] Currently, the commercial application of perovskite solar cells is mainly limited by their poor environmental stability. Perovskite materials are extremely sensitive to factors such as water, oxygen, and heat, leading to rapid performance degradation. Traditional back-end packaging technologies (such as covering the complete device with a glass or polymer cover) have inherent defects:

[0003] Interface problem: There is a physical gap between the encapsulation layer and the perovskite active layer, which cannot effectively block the lateral penetration of water and oxygen and interface erosion.

[0004] Process damage: Post-packaging processes (such as hot pressing and bonding) may involve high temperatures or solvents, causing irreversible damage to the fragile perovskite lattice and the interface of the formed charge transport layer.

[0005] Stress mismatch: The thermal expansion coefficients of the independent packaging layer and the various layers of the device do not match, which can easily generate internal stress during long-term use, leading to delamination or cracking.

[0006] Therefore, developing an in-situ encapsulation technology that is perfectly compatible with perovskite layers and can be implemented under mild conditions has become a key problem that urgently needs to be solved in this field. Summary of the Invention

[0007] The purpose of this invention is to address the problems existing in the prior art by providing a nanosheet-resin composite UV-cured perovskite solar cell and its preparation method, particularly a perovskite solar cell based on an MXene monolayer / epoxy acrylate UV in-situ cured composite modification layer and its preparation method.

[0008] This invention is the first to blend monolayer nanosheets with epoxy acrylate at a mass ratio of 10-15:85-90, and then use an in-situ UV curing process to form an integrated perovskite layer in-situ encapsulation and modification layer that combines conductivity, moisture barrier, and mechanical reinforcement functions, achieving simultaneous "deposition-encapsulation". This solution solves the problems of thermal / solvent damage and interfacial stress caused by traditional post-encapsulation, and significantly improves the device's humidity and thermal cycling stability.

[0009] The objective of this invention can be achieved through the following methods: This invention provides a nanosheet-resin composite UV-curable perovskite solar cell, comprising the following components arranged sequentially: Conductive substrate, hole transport layer, perovskite light-absorbing layer, monolayer nanosheet-epoxy acrylate composite modification layer, electron transport layer, electrode; The nanosheet-resin composite modification layer includes a single layer of nanosheets and epoxy acrylate.

[0010] As one embodiment of the present invention, the monolayer nanosheet includes one or more of MXene monolayer nanosheets, graphene monolayer nanosheets, graphene derivative monolayer nanosheets (such as graphene oxide, fluorinated graphene), transition metal chalcogenide monolayer nanosheets, hexagonal boron nitride monolayer nanosheets, and black phosphorus monolayer nanosheets.

[0011] Graphene derivative monolayer nanosheets include one or more of graphene oxide and fluorinated graphene. Graphene and its derivatives are classic two-dimensional conductive / barrier materials, and incorporating them covers a very wide range of materials. Different degrees of oxidation / functionalization of the derivatives can also tune hydrophilicity and interfacial interactions.

[0012] Transition metal chalcogenides include one or more of MoS2 and WS2. Transition metal chalcogenides possess semiconductor properties and tunable work functions, allowing for finer interface energy level matching.

[0013] Hexagonal boron nitride monolayer nanosheets: known as "white graphene", they are excellent insulators and high thermal conductivity materials, emphasizing barrier and heat dissipation functions.

[0014] Black phosphorus monolayer nanosheets: with tunable direct band gap and high carrier mobility, they are a high-potential option.

[0015] The preferred monolayer nanosheets are MXene monolayer nanosheets, and the interaction between MXene monolayer nanosheets and epoxy acrylate is as follows: Chemical interactions: The abundant functional groups (such as -OH, -O, -F) on the surface of MXene nanosheets may form hydrogen bonds with the ester and epoxy groups in the epoxy acrylate prepolymer. More importantly, during UV-initiated free radical curing, some unsaturated bonds or functional groups on the MXene surface may participate in or partially participate in the cross-linking reaction, forming chemical bonds at the interface.

[0016] Physical interaction: The liquid epoxy acrylate prepolymer fully impregnates the MXene nanosheets, and the cross-linked polymer network formed after curing tightly wraps and anchors the MXene nanosheets, forming a typical "brick-and-mortar" composite structure (MXene is the "brick" and the polymer is the "mortar").

[0017] As one embodiment of the present invention, a method for preparing a nanosheet-resin composite modification layer is as follows: The monolayer nanosheets were added to the solvent and magnetically stirred to obtain a dispersion. Then, epoxy acrylate prepolymer, photoinitiator and functional additives were added and stirred again. After standing and degassing, the composite modified layer solution was obtained. The composite modification layer solution was spin-coated onto the perovskite light-absorbing layer and cured with ultraviolet light to form a film, thus obtaining a single-layer nanosheet-epoxy acrylate composite modification layer.

[0018] After the composite modification layer solution is applied, it can be cured instantly at low temperature: the UV curing process is completed instantly (in seconds) at room temperature, completely avoiding the thermal stress damage and decomposition of the perovskite lattice caused by prolonged high temperature in the traditional thermal curing process. At the same time, it can form a tight interface in situ: the liquid slurry can well wet the perovskite surface, and the composite modification layer formed after curing has a tight physical contact with the perovskite without gaps, achieving a seamless connection.

[0019] The cured epoxy acrylate itself forms a dense, low-porosity cross-linked polymer film, possessing intrinsic barrier properties against water and oxygen. Meanwhile, single-layer nanosheets, such as MXene, exert a "maze effect": two-dimensional MXene nanosheets are uniformly dispersed within the polymer matrix, acting like countless parallel, impermeable "barriers" within the polymer. Water and oxygen molecules must bypass these nanosheets when permeating the film, significantly lengthening the permeation path and thus substantially reducing water and oxygen permeability. The two work synergistically: epoxy acrylate ensures the integrity of the film and immobilizes MXene, while MXene greatly enhances the barrier properties of the polymer film. The combination produces a synergistic barrier effect of "1+1>>2". Neither epoxy acrylate film nor MXene film alone can achieve such excellent barrier levels.

[0020] Preferably, the concentration of monolayer nanosheets in the dispersion is 5-10 mg / ml. The solvent includes anhydrous chlorobenzene (CB).

[0021] Preferably, the mass ratio of single-layer nanosheets to epoxy acrylate prepolymer is 10-15:85-90.

[0022] Preferably, the mass ratio of monolayer nanosheets to photoinitiator is 10-15:1-2.

[0023] Preferably, the mass ratio of single-layer nanosheets to functional additives is 10-15:1-2.

[0024] Preferably, the photoinitiator is one or more of TPO (initiator) and TEA (co-initiator).

[0025] Preferably, the functional additive is trimethylolpropane triacrylate (TMPTA).

[0026] Preferably, the magnetic stirring speed is 250-350 rpm, and the time is 1.5-2.5 h. The magnetic stirring is carried out under nitrogen protection.

[0027] Preferably, after magnetic stirring, centrifugation is performed to remove the precipitate and obtain a dispersion. The centrifugation speed is 7000-9000 rpm and the time is 8-12 min.

[0028] Preferably, the stirring speed is continued at 250-350 rpm for 8-12 minutes. The epoxy acrylate prepolymer is added under light-protected conditions while stirring continues.

[0029] Preferably, the spin coating speed is 2500-3500 rpm and the time is 25-35 s. The ambient humidity for spin coating is <5%RH.

[0030] Preferably, UV curing is performed using ultraviolet light (365nm) irradiation. The intensity of the ultraviolet light irradiation is 40-60mW / cm². 2 The duration of ultraviolet light irradiation is 10-20 seconds.

[0031] In one embodiment of the present invention, the conductive substrate is FTO.

[0032] In one embodiment of the present invention, the hole transport layer material includes one of organic HTL and inorganic HTL. Organic HTL includes one of Spiro-OMeTAD, PEDOT:PSS, and SAMs. Inorganic HTL includes one of nickel oxide and tin oxide.

[0033] In one embodiment of the present invention, the perovskite light-absorbing layer is made of ABX3 type perovskite. Wherein, A represents cesium ions (Cs). + ), rubidium ions (Ru + ), Methylamino (MA) + ), formamidinyl (FA + B is any one or at least two of the following: ) 2+ ) and / or tin ions (Sn 2+ X is bromide ion (Br) ), iodide ions (I) ), chloride ions (Cl) Any one or at least two of the following.

[0034] In one embodiment of the present invention, the electron transport layer comprises one of a metal oxide and an organic material. The metal oxide includes TiO2, SnO2, and CeO2. x One of them; organic materials include PCBM and in-situ cyclized polyacrylonitrile.

[0035] In one embodiment of the present invention, the electrode includes a back electrode and a transparent conductive electrode. The back electrode includes a metal electrode (Au / Ag), a carbon-based electrode, and a bilayer metal electrode; the transparent conductive electrode includes TCOs (ITO / FTO), metal mesh / nanowires, and composite structures (such as NiO / Ag / NiO).

[0036] In one embodiment of the present invention, the thickness of the hole transport layer is 20-50 nm.

[0037] The thickness of the perovskite light-absorbing layer is 450-550 nm.

[0038] The thickness of the MXene-epoxy acrylate composite modification layer is 5-10 nm.

[0039] The thickness of the electron transport layer is 35-50 nm.

[0040] The thickness of the electrode is 80 nm-150 nm.

[0041] This invention also provides a method for preparing a perovskite solar cell containing an MXene-epoxy acrylate composite modification layer, comprising the following steps: S1. Conductive substrate pretreatment; S2. Prepare a hole transport layer on a conductive substrate; S3. Spin-coat the perovskite light-absorbing layer precursor solution onto the hole transport layer, and anneal the solution to prepare the perovskite light-absorbing layer. S4. Spin-coat the composite modification layer solution onto the perovskite light-absorbing layer to prepare a single-layer nanosheet-epoxy acrylate composite modification layer; S5. Deposit an electron transport layer on a single-layer nanosheet-epoxy acrylate composite modification layer; S6. Electrodes are fabricated on the electron transport layer to obtain a perovskite solar cell.

[0042] In one embodiment of the present invention, in step S1, the pretreatment of the conductive substrate is ultraviolet ozone treatment for 15-25 minutes.

[0043] As one embodiment of the present invention, in step S2, the preparation parameters of the hole transport layer are: 3500-4500 rpm, 25-35s, annealing at 110-130℃ for 10-20min.

[0044] In one embodiment of the present invention, in step S3, the annealing temperature is 90-110°C and the time is 8-12 minutes. A one-step or two-step spin-coating method is used to coat the perovskite light-absorbing layer precursor solution.

[0045] As one embodiment of the present invention, in step S3, in a nitrogen glove box, the materials of the perovskite light-absorbing layer are weighed according to the molar ratio of the perovskite composition, dissolved in a solvent (DMF and DMSO with a volume ratio of 3-5:1) to prepare a precursor solution (concentration of 0.5-1.5.0 mol / L). The precursor solution is then spin-coated onto the hole transport layer (rotation speed of 4000 rpm / 30s). 250-350 μL of the anti-solvent chlorobenzene is added dropwise at the 4-5s countdown. The mixture is then annealed (annealed at 90-110℃ for 8-12 min) to prepare the perovskite light-absorbing layer.

[0046] In one embodiment of the present invention, in step S4, the composite modified layer solution is prepared by adding monolayer nanosheets to a solvent, stirring magnetically to obtain a dispersion, then adding epoxy acrylate prepolymer, photoinitiator, and functional additives and continuing stirring, followed by standing to remove bubbles to obtain the composite modified layer solution. During the preparation of the composite modified layer solution, light-protected conditions should be maintained as much as possible.

[0047] Epoxy acrylate is a UV-curable material. Conventionally, directly coating a polymer precursor solution onto a perovskite surface can lead to solvents dissolving or damaging the perovskite layer. However, the chlorobenzene used in this invention has extremely low solubility for fully crystalline perovskite films (such as MAPbI3). This invention does not use a "corrosive solution" that would damage the perovskite, but rather a "functional slurry" that is chemically inert to the perovskite. The coating process of this invention occurs after the perovskite light-absorbing layer has fully crystallized and formed a stable film, but before the deposition of the electron transport layer, perfectly avoiding the solvent-sensitive stage of the perovskite precursor solution or intermediate phase. This invention uses UV light-initiated free radical polymerization, and the curing process is completed instantaneously within seconds to tens of seconds, constituting "flash" curing. Even if the slurry contains trace amounts of mild solvent, its contact time with the perovskite surface is minimized due to rapid curing, resulting in minimal risk of physical damage. This invention can rapidly construct a physical barrier: under UV irradiation, the epoxy acrylate rapidly crosslinks, locking MXene nanosheets within the newly formed polymer network. This initially formed dense network immediately becomes an isolation layer, further blocking the contact between the remaining solvent components in the slurry and the perovskite.

[0048] Compared with the prior art, the present invention has the following beneficial effects: By leveraging the synergistic effect of MXene-epoxy acrylate composite layer and UV curing, three key issues in the field of perovskite solar cells have been resolved: (1) Poor environmental stability: Perovskite materials are extremely sensitive to water (H2O) and oxygen (O2), and will decompose rapidly in humid, light-exposed and heated environments, leading to permanent failure of battery performance. This is the primary bottleneck restricting its commercial application. This invention solves the problems of insufficient barrier properties and poor interfacial compatibility of traditional encapsulation materials by using a blend of single-layer nanosheets (5-15 parts by weight) and epoxy acrylate prepolymer (80-95 parts by weight), thus preparing a perovskite battery with both super strong water and oxygen barrier properties and high efficiency in humid environments after encapsulation, compared with unencapsulated perovskite batteries.

[0049] (2) Efficiency loss due to interface defects: There are a large number of dangling bonds and uncoordinated ions (such as Pb²) at the interface between the perovskite light-absorbing layer and the charge transport layer (such as the electron transport layer). + These defects become nonradiative recombination centers for charge carriers, trapping electrons or holes and causing a decrease in open-circuit voltage (Voc) and fill factor (FF), resulting in actual efficiency far below the theoretical limit. This invention addresses the efficiency loss caused by interface defects through the synergistic effect of nanosheet surface functional groups, the chemical passivation of perovskite, and the physical encapsulation of an epoxy acrylate crosslinking network, leading to a significant improvement in battery efficiency. The principle of solving efficiency loss using MXene surface functional groups (-O / -F) as an example is as follows: Physical passivation: Liquid composite slurry can penetrate into the nanoscale pores and grain boundaries of perovskite films, and after solidification, it directly seals these defect sites, reducing non-radiative recombination centers.

[0050] Chemical passivation: Functional groups (such as -F, -OH) on the MXene surface can interact with uncoordinated Pb²⁺ on the perovskite surface. + Ions coordinate with each other, effectively passivating these charged defects and suppressing carrier recombination at the interface.

[0051] Energy level optimization: MXene has an adjustable work function, and its introduction may optimize the energy level alignment between the perovskite and the electron transport layer, promote electron extraction and transport, and reduce interface energy loss.

[0052] (3) Poor process compatibility between traditional encapsulation technology and perovskite devices: Existing standalone post-encapsulation technology is difficult to perfectly match with perovskite devices that are sensitive to heat, solvents, and mechanical stress. During the encapsulation process or after long-term use, new damage or stress is easily introduced, and effective and durable protection cannot be provided. Unlike standalone post-encapsulation technology, this invention is the first to blend MXene monolayer nanosheets with epoxy acrylate and form an integrated perovskite layer in-situ encapsulation modification layer with conductive, moisture barrier and mechanical enhancement functions through an ultraviolet in-situ curing process, so as to achieve simultaneous "deposition-encapsulation". Attached Figure Description

[0053] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 The images show the physical morphology of the devices prepared in Example 1 and Comparative Example 1, where A represents the device with an in-situ passivation layer and B represents the device without a passivation layer. Figure 2 The images show the physical morphology of the devices in Example 1 and Comparative Example after 130 days. In Example 1, A-30 Days represents the device with an in-situ passivation layer, and B-30 Days represents the device without a passivation layer. Figure 3 The JV curves for Example 1 and Comparative Example 1; Figure 4 The JV curves for Examples 1, 2-1, 2-2, and 2-3 are shown. Figure 5 Here are statistical charts of efficiency data for Examples 1, 2-1, 2-2, and 2-3; Figure 6 The JV curves for Example 1 and Comparative Example 3; Figure 7 The JV curves for Example 1 and Comparative Example 4; Figure 8 The JV curves for Example 1 and Comparative Example 5; Figure 9 The JV curves for Example 1 and Comparative Example 6; Figure 10 The following are statistical charts of efficiency data from Examples 3-6. Detailed Implementation

[0054] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The following examples are implemented under the premise of the technical solution of the present invention, providing detailed implementation methods and specific operating procedures, which will help those skilled in the art to further understand the present invention. It should be noted that the scope of protection of the present invention is not limited to the following embodiments; any adjustments and improvements made under the concept of the present invention are all within the scope of protection of the present invention.

[0055] This invention provides a perovskite solar cell containing a single-layer nanosheet-epoxy acrylate composite modification layer, comprising, in sequence: a conductive substrate, a hole transport layer, a perovskite light-absorbing layer, a single-layer nanosheet-epoxy acrylate composite modification layer, an electron transport layer, and an electrode; wherein the single-layer nanosheet-epoxy acrylate composite modification layer comprises single-layer nanosheets and epoxy acrylate.

[0056] The epoxy acrylate in this invention has the following functions: (1) UV-curable matrix: As a reactive prepolymer, it can rapidly crosslink to form a dense three-dimensional network structure under the action of photoinitiator and ultraviolet light, which constitutes the main framework of the composite modification layer and provides basic mechanical strength and encapsulation.

[0057] (2) Dispersing and fixing monolayer nanosheets: Its liquid prepolymer form can be used as a dispersion medium for nanosheets, and the MXene nanosheets can be "locked" in the polymer grid by solidification to prevent them from agglomerating or migrating, thus constructing a stable composite structure.

[0058] (3) Interface wetting and adhesion: It has good wettability with the perovskite layer, and after curing, it can form a tight physical contact and strong adhesion with the perovskite surface.

[0059] Example 1 This embodiment prepares a perovskite solar cell containing an MXene-epoxy acrylate composite modification layer, comprising, in sequence: a conductive substrate, a hole transport layer, a perovskite light-absorbing layer, an MXene-epoxy acrylate composite modification layer, an electron transport layer, and an electrode. The preparation method is as follows: (1) Pretreatment of conductive substrate: FTO glass was treated with ultraviolet ozone for 20 min; (2) A hole transport layer (nickel oxide, 40 nm thick) was prepared on a conductive substrate. The preparation parameters were: 4000 rpm / 30 s, annealing at 120 °C for 15 min. (3) In a nitrogen glove box, according to the perovskite Cs 0.05 MA 0.05 FA 0.9 Pb(I 0.95 Br 0.05 Weigh CsI, FAI, MAI, PbI2, and PbBr2 in the molar ratio of 4:1 and dissolve them in DMF and DMSO solvents to prepare a 1.0 mol / L precursor solution. Spin-coat the perovskite light-absorbing layer precursor solution onto the hole transport layer at 4000 rpm for 30 s. Add 300 μL of the antisolvent chlorobenzene at the 5-second countdown and anneal (100 °C for 10 min) to prepare a perovskite light-absorbing layer (500 nm thick). (4) Take 0.5g of monolayer Ti3C2T x The powder was added to 50 ml of anhydrous chlorobenzene (CB) and magnetically stirred (300 rpm) for 2 hours under nitrogen protection to avoid ultrasonic treatment and prevent the film from breaking. The precipitate was removed by centrifugation (8000 rpm, 10 min) to obtain a monolayer MXene / CB dispersion with a concentration of about 5 mg / ml.

[0060] Under light-protected conditions, 85 parts of epoxy acrylate prepolymer were mixed with MXene / CB dispersion (the mass ratio of epoxy acrylate prepolymer to MXene was 85:15), and 1.5 parts of silane coupling agent KH-560 were added.

[0061] Add photoinitiator TPO (1 part) and TEA (1 part), continue stirring for 10 minutes, and then let stand to remove bubbles; The prepared high-performance composite modification layer solution was spin-coated (spray coating parameters: 3000 rpm / 30 s, ambient humidity <5%RH) onto the perovskite light-absorbing layer. Then, it was irradiated with 365 nm ultraviolet light (intensity 50 mW / cm²). 2 The film was formed by UV curing with an exposure time of 10 seconds to obtain an MXene-epoxy acrylate composite modified layer (10 nm thick). (5) Depositing an electron transport layer (C) on the MXene-epoxy acrylate composite modified layer. 60 (thickness is 45nm). (6) An electrode (Ag, 100 nm) is prepared on the electron transport layer to obtain a perovskite solar cell.

[0062] Example 2 This embodiment prepared a perovskite solar cell containing an MXene-epoxy acrylate composite modification layer. The structure and preparation method are basically the same as those in Example 1, except that the mass ratio of epoxy acrylate prepolymer and MXene was changed.

[0063] The degradation of the perovskite solar cells prepared in Examples 1 and 2 is shown in Table 1: Table 1

[0064] Example 3 This embodiment prepares a perovskite solar cell containing a single-layer nanosheet-epoxy acrylate composite modification layer. The structure and preparation method are basically the same as those in Example 1, the only difference being that the single-layer Ti3C2T... x Replace with graphene and its derivatives: graphene oxide.

[0065] Example 4 This embodiment prepares a perovskite solar cell containing a single-layer nanosheet-epoxy acrylate composite modification layer. The structure and preparation method are basically the same as those in Example 1, the only difference being that the single-layer Ti3C2T... x Replace with a transition metal chalcogenide: MoS2.

[0066] Example 5 This embodiment prepares a perovskite solar cell containing a single-layer nanosheet-epoxy acrylate composite modification layer. The structure and preparation method are basically the same as those in Example 1, the only difference being that the single-layer Ti3C2T... x Replace with hexagonal boron nitride monolayer nanosheets.

[0067] Example 6 This embodiment prepares a perovskite solar cell containing a single-layer nanosheet-epoxy acrylate composite modification layer. The structure and preparation method are basically the same as those in Example 1, the only difference being that the single-layer Ti3C2T... x Replace with black phosphorus monolayer nanosheets.

[0068] Comparative Example 1 This comparative example prepared a perovskite solar cell with the same structure and preparation method as Example 1, except that no composite modification layer was prepared.

[0069] The perovskite solar cells prepared in Example 1 and Comparative Example 1 are as follows: Figure 1 As shown, A is a device with an in-situ passivation layer (Example 1); B is a device without a passivation layer (Comparative Example 1). The device morphology after 30 days is shown in the figure. Figure 2 As shown, A-30Day is the device with an in-situ passivation layer (Example 1), in which the perovskite layer showed no obvious degradation; B-30Day is the device without a passivation layer (Comparative Example 1), in which the perovskite layer has yellowed and degraded.

[0070] This invention addresses efficiency loss caused by interface defects by synergistically combining the chemical passivation effect of MXene nanosheet surface functional groups (-O / -F) with perovskite and the physical encapsulation of epoxy acrylate crosslinking network, thereby significantly improving battery efficiency.

[0071] The preparation method is as follows: (1) Pretreatment of conductive substrate: FTO glass was treated with ultraviolet ozone for 20 min; (2) A hole transport layer was prepared on a conductive substrate. The preparation parameters were: 4000 rpm / 30s, annealing at 120℃ for 15min. (3) Spin-coat the perovskite light-absorbing layer precursor solution onto the hole transport layer and anneal it (anneal at 100℃ for 10 min) to prepare the perovskite light-absorbing layer. (4) Electrodes are fabricated on the electron transport layer to obtain perovskite solar cells.

[0072] Comparative Example 2 This comparative example prepared a perovskite solar cell with the same structure and preparation method as Example 1, except that different epoxy acrylate prepolymers and MXene ratios (95:5, 80:20) were used.

[0073] Comparative Example 3 This comparative example prepared a perovskite solar cell with the same structure and preparation method as Example 1, except that the epoxy acrylate prepolymer was replaced with PMMA prepolymer.

[0074] PMMA is typically a thermoplastic resin that requires high-temperature melting or solvent evaporation to form a film, posing a risk of heat damage or solvent corrosion. Epoxy acrylates, on the other hand, can be cured at room temperature under UV light, avoiding these problems. After curing, the density of its crosslinked network, solvent resistance, and mechanical strength are all superior to those of linear polymer PMMA.

[0075] The preparation method is as follows: (1) Pretreatment of conductive substrate: FTO glass was treated with ultraviolet ozone for 20 min; (2) A hole transport layer was prepared on a conductive substrate. The preparation parameters were: 4000 rpm / 30s, annealing at 120℃ for 15min. (3) Spin-coat the perovskite light-absorbing layer precursor solution onto the hole transport layer and anneal it (anneal at 100℃ for 10 min) to prepare the perovskite light-absorbing layer. (4) Add 0.5g of monolayer Ti3C2Tx powder to 50ml of anhydrous chlorobenzene (CB), and stir magnetically (300rpm) for 2 hours under nitrogen protection to avoid ultrasonic treatment and prevent the sheet from breaking; centrifuge (8000rpm, 10min) to remove the precipitate and obtain a monolayer MXene / CB dispersion with a concentration of about 5mg / ml.

[0076] Under light-protected conditions, PMMA (85 parts) was mixed with MXene / CB dispersion (PMMA:MXene mass ratio of 85:15), and silane coupling agent KH-560 (1.5 parts) was added.

[0077] Add photoinitiator TPO and TEA (2 parts in total), continue stirring for 10 minutes, and then let stand to remove bubbles; The prepared high-performance composite modification layer solution was spin-coated (spray coating parameters: 3000 rpm / 30 s, ambient humidity <5%RH) onto the perovskite light-absorbing layer. Then, it was irradiated with 365 nm ultraviolet light (intensity 50 mW / cm²). 2 The MXene-PMMA composite modified layer was obtained by UV curing technology (exposure time 20 seconds) to form a film. (5) Deposit an electron transport layer on the MXene-PMMA composite modified layer; (6) Electrodes are fabricated on the electron transport layer to obtain a perovskite solar cell.

[0078] Comparative Example 4 This comparative example prepared a perovskite solar cell with the same structure and preparation method as Example 1, except that the epoxy acrylate prepolymer was replaced with diethylene glycol diacrylate.

[0079] The present invention also conducted experiments on other crosslinking resins, such as diethylene glycol diacrylate, but the results were not as good as those of the epoxy acrylate of the present invention.

[0080] Diethylene glycol diacrylate is a small-molecule crosslinking agent, and its crosslinking density may be too high after curing, resulting in a brittle film and poor stress compatibility with the perovskite interface. Epoxy acrylate, as a prepolymer, has a longer molecular chain, providing better flexibility and interfacial adhesion, forming a composite layer that combines rigidity and flexibility.

[0081] The epoxy acrylate of the present invention has the following effects: (1) Synergistic effect: This "rigid-flexible" structure enables its solidified network to resist external scratches and deformations, and to disperse energy through micro-deformation when subjected to bending stress, thus avoiding the brittle fracture of purely rigid materials. In contrast, the short-chain structure of diethylene glycol diacrylate results in its network being more flexible than rigid, and it is brittle overall; PMMA, on the other hand, is a typical rigid-brittle material due to its carbon-carbon backbone and large α-methyl side groups.

[0082] (2) Ideal dual functional groups: Reactive end groups: Acryloyloxy groups, located at both ends of the molecular chain, ensure efficient free radical copolymerization, enabling long-chain crosslinking between prepolymers to construct a three-dimensional network that is both strong and resilient.

[0083] Functional side groups: secondary hydroxyl groups, which are strongly polar groups introduced after the ring-opening reaction of the epoxy group. They do not participate in the curing reaction, but can: Enhanced adhesion: The formation of strong hydrogen bonds with the polar atoms on the perovskite layer and MXene nanosheet surface is the chemical basis for achieving "seamless" in-situ encapsulation and preventing interface delamination.

[0084] (3) Diethylene glycol diacrylate homopolymer exhibits high hardness but is extremely brittle due to its dense crosslinking points and short chain segments; while PMMA is a linear polymer with acceptable hardness but poor flexibility and is prone to creep. The "rigid-flexible" network of epoxy acrylate has irreplaceable advantages in the flexible application scenarios of perovskite batteries.

[0085] The preparation method is as follows: (1) Pretreatment of conductive substrate: FTO glass was treated with ultraviolet ozone for 20 min; (2) A hole transport layer was prepared on a conductive substrate. The preparation parameters were: 4000 rpm / 30s, annealing at 120℃ for 15min. (3) Spin-coat the perovskite light-absorbing layer precursor solution onto the hole transport layer and anneal it (anneal at 100℃ for 10 min) to prepare the perovskite light-absorbing layer. (4) Take 0.5g of monolayer Ti3C2T x The powder was added to 50 ml of anhydrous chlorobenzene (CB) and magnetically stirred (300 rpm) for 2 hours under nitrogen protection to avoid ultrasonic treatment and prevent the film from breaking. The precipitate was removed by centrifugation (8000 rpm, 10 min) to obtain a monolayer MXene / CB dispersion with a concentration of about 5 mg / ml.

[0086] Under light-protected conditions, diethylene glycol diacrylate (85 parts) was mixed with MXene / CB dispersion (diethylene glycol diacrylate and MXene mass ratio of 85:15), and silane coupling agent KH-560 (1.5 parts) was added.

[0087] Add photoinitiator TPO and TEA (2 parts in total), continue stirring for 10 minutes, and then let stand to remove bubbles; The prepared high-performance composite modification layer solution was spin-coated (spray coating parameters: 3000 rpm / 30 s, ambient humidity <5%RH) onto the perovskite light-absorbing layer. Then, it was irradiated with 365 nm ultraviolet light (intensity 50 mW / cm²). 2 The film was formed by UV curing (exposure time 20 seconds) to obtain the MXene-diethylene glycol diacrylate composite modified layer; (5) Deposit an electron transport layer on the MXene-diethylene glycol diacrylate composite modification layer; (6) Electrodes are fabricated on the electron transport layer to obtain a perovskite solar cell.

[0088] Comparative Example 5 This comparative example prepared a perovskite solar cell with the same structure and preparation method as Example 1, except that equal amounts of epoxy acrylate prepolymer and initiator were added to the perovskite light-absorbing layer precursor solution.

[0089] Epoxy acrylate is encapsulated in situ by in-situ polymerization with a thermal initiator in the perovskite light-absorbing layer. Without MXene nanosheets, the conductive / carrier extraction function is lacking. Thermal curing requires temperatures above 80°C, which can easily damage the perovskite.

[0090] Other composite encapsulation or edge encapsulation methods: such as polyurethane matrix, room temperature curing but requiring ALD equipment, at RH 60% T 80 =1200 hours; UV adhesive sealing of the silicon frame edge improves airtightness, but rigid structures are not suitable for flexible devices and have limitations: ALD process equipment is expensive (>$500k / unit), and the yield of large-area fabrication is <80%; edge encapsulation cannot solve the problem of intrinsic degradation of the perovskite layer surface.

[0091] The preparation method is as follows: (1) Pretreatment of conductive substrate: FTO glass was treated with ultraviolet ozone for 20 min; (2) A hole transport layer was prepared on a conductive substrate. The preparation parameters were: 4000 rpm / 30s, annealing at 120℃ for 15min. (3) Preparation of blending precursor solution and perovskite light-absorbing layer: The epoxy acrylate prepolymer and thermal initiator (such as benzoyl peroxide, BPO) are directly added to the perovskite light-absorbing layer precursor solution (Cs 0.05 MA 0.05 FA 0.9 Pb(I 0.95 Br 0.05 The perovskite-polymer blend precursor solution was uniformly mixed in a DMF / DMSO solution to form a perovskite-polymer blend precursor solution. The amounts of epoxy acrylate prepolymer and initiator added were the same as the mass of solids contained in an equivalent amount of composite modified layer in the examples.

[0092] The aforementioned blended precursor liquid is spin-coated onto the hole transport layer and immediately subjected to a two-step annealing process (e.g., first treated at 65°C for 1 minute, then treated at 100°C for 15 minutes). During this process, perovskite crystallization and thermally initiated polymerization and curing of epoxy acrylate occur simultaneously, forming a perovskite light-absorbing layer with an embedded polymer network.

[0093] (4) Electron transport layer deposition: deposit an electron transport layer (such as C60, PCBM or SnO2) directly on the perovskite light-absorbing layer prepared in step (3). (5) Electrode preparation: Metal electrodes (such as Ag or Cu) are prepared on the electron transport layer by thermal evaporation or magnetron sputtering to obtain the comparative perovskite solar cell.

[0094] Comparative Example 6 This comparative example prepared a perovskite solar cell with a structure and preparation method basically the same as in Example 1, the only difference being that equal amounts of Ti3C2T were used. x The powder was added to the perovskite light-absorbing layer precursor solution.

[0095] The preparation method is as follows: (1) Pretreatment of conductive substrate: FTO glass was treated with ultraviolet ozone for 20 min; (2) A hole transport layer was prepared on a conductive substrate. The preparation parameters were: 4000 rpm / 30s, annealing at 120℃ for 15min. (3) Preparation of blended precursor solution and perovskite light-absorbing layer: Equal amounts of Ti3C2T x Powder is directly added to the perovskite light-absorbing layer precursor solution (Cs 0.05 MA0.05 FA 0.9 Pb(I 0.95 Br 0.05 The perovskite-Ti3C2Tx powder is uniformly mixed in a DMF / DMSO solution to form a perovskite-Ti3C2Tx powder blend precursor solution.

[0096] The above-mentioned blended precursor liquid was spin-coated onto the hole transport layer and immediately subjected to a two-step annealing treatment (first at 65°C for 1 minute, then at 100°C for 15-20 minutes). During this process, perovskite crystallization and thermally initiated polymerization and curing of epoxy acrylate occurred simultaneously, forming a perovskite light-absorbing layer with an embedded polymer network.

[0097] (4) Electron transport layer deposition: deposit an electron transport layer (such as C60, PCBM or SnO2) directly on the perovskite light-absorbing layer prepared in step (3). (5) Electrode preparation: Metal electrodes (such as Ag or Cu) are prepared on the electron transport layer by thermal evaporation or magnetron sputtering to obtain the comparative perovskite solar cell.

[0098] The degradation of the perovskite solar cells prepared in Example 1 and the comparative example is as follows: Figure 1-2 As shown.

[0099] Figure 1 The images show the physical morphology of the devices prepared in Example 1 and Comparative Example 1, where A represents the device with an in-situ passivation layer and B represents the device without a passivation layer. Figure 2 The images show the physical morphology of the devices in Example 1 and Comparative Example 1 after 30 days. In the example, A-30 Days represents the device with an in-situ passivation layer, and B-30 Days represents the device without a passivation layer. The degradation of the perovskite solar cells prepared in Example 1 and the comparative example is shown in Table 2: Table 2

[0100] Performance testing: IV curve tests were performed on the perovskite photovoltaic cells using an AM 1.5G standard solar simulator and a 2400 source meter to obtain the device's performance parameters (Voc, FF, Jsc, PCE), where the light source intensity was 100 mW / cm². 2 The test conditions were a glove box environment with N2 introduced; JV curve tests were performed on single-electron or single-hole devices in a dark environment using a 2400V meter, with the test voltage range being 0~2V.

[0101] The test results of the examples and comparative examples are as follows: Figure 3-9 As shown Figure 3The JV curves are for Example 1 and Comparative Example 1. The efficiency of Example 1 is 25.79%, and the efficiency of Comparative Example 1 is 20.04%. Figure 4 The JV curves are for Examples 1, 2-1, 2-2, and 2-3. Figure 5 The chart shows the efficiency data statistics for Examples 1, 2-1, 2-2, and 2-3. The efficiency of Example 1 (85:15) is 25.79%, the efficiency of Example 2-1 (90:10) is 24.15%, the efficiency of Example 2-2 (95:5) is 23.31%, and the efficiency of Example 2-3 (80:20) is 23.73%.

[0102] Figure 6 The JV curves are for Example 1 and Comparative Example 3. The efficiency of Example 1 is 25.79%, and the efficiency of Comparative Example 3 is 21.94%. Figure 7 The JV curves are for Example 1 and Comparative Example 4. The efficiency of Example 1 is 25.79%, and the efficiency of Comparative Example 4 is 22.19%. Figure 8 The JV curves are for Example 1 and Comparative Example 5. The efficiency of Example 1 is 25.79%, and the efficiency of Comparative Example 5 is 22.83%. Figure 9 The JV curves are for Example 1 and Comparative Example 6. The efficiency of Example 1 is 25.79%, and the efficiency of Comparative Example 6 is 23.19%. Figure 10 Efficiency statistics for Examples 3, 4, 5, and 6 are presented. The efficiency of Example 3 is 24.33%, that of Example 4 is 24.2%, that of Example 5 is 24.13%, and that of Example 6 is 24.82%. The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A nanosheet-resin composite UV-curable perovskite solar cell, characterized in that, Including the following settings in sequence: Conductive substrate, hole transport layer, perovskite light-absorbing layer, monolayer nanosheet-epoxy acrylate composite modification layer, electron transport layer, electrode; The nanosheet-resin composite modification layer includes a single layer of nanosheets and epoxy acrylate.

2. The UV-curable perovskite solar cell according to claim 1, characterized in that, Monolayer nanosheets include one or more of the following: MXene monolayer nanosheets, graphene monolayer nanosheets, graphene derivative monolayer nanosheets, transition metal chalcogenide monolayer nanosheets, hexagonal boron nitride monolayer nanosheets, and black phosphorus monolayer nanosheets.

3. The UV-curable perovskite solar cell according to claim 1, characterized in that, Preparation method of nanosheet-resin composite modification layer: The monolayer nanosheets were added to the solvent and magnetically stirred to obtain a dispersion. Then, epoxy acrylate prepolymer, photoinitiator and functional additives were added and stirred again. After standing and degassing, the composite modified layer solution was obtained. The composite modification layer solution was spin-coated onto the perovskite light-absorbing layer and cured with ultraviolet light to form a film, thus obtaining a single-layer nanosheet-epoxy acrylate composite modification layer.

4. The UV-curable perovskite solar cell according to claim 3, characterized in that, In the dispersion, the concentration of monolayer nanosheets is 5-10 mg / ml; And / or, the mass ratio of monolayer nanosheets to epoxy acrylate prepolymer is 10-15:85-90; And / or, the mass ratio of monolayer nanosheets to photoinitiator is 10-15:1-2; And / or, the mass ratio of monolayer nanosheets to functional additives is 10-15:1-2; And / or, the photoinitiator is one or more of TPO and TEA; And / or, the functional additive is trimethylolpropane triacrylate; And / or, the solvent includes anhydrous chlorobenzene.

5. The UV-curable perovskite solar cell according to claim 3, characterized in that, The magnetic stirring speed is 250-350 rpm, and the time is 1.5-2.5 hours; And / or, after magnetic stirring, centrifugation is performed to remove the precipitate and obtain a dispersion; the centrifugation speed is 7000-9000 rpm and the time is 8-12 min; And / or, continue stirring at a speed of 250-350 rpm for 8-12 minutes; And / or, the spin coating speed is 2500-3500 rpm and the time is 25-35 s; And / or, UV curing involves irradiating with ultraviolet light at an intensity of 40-60 mW / cm². 2 The duration of ultraviolet light irradiation is 10-20 seconds.

6. The UV-curable perovskite solar cell according to claim 1, characterized in that, The conductive substrate is FTO; And / or, the hole transport layer material includes one of organic HTL and inorganic HTL; organic HTL includes one of Spiro-OMeTAD, PEDOT:PSS, and SAMs materials; inorganic HTL includes one of nickel oxide and tin oxide materials.

7. The UV-curable perovskite solar cell according to claim 1, characterized in that, The perovskite light-absorbing layer is made of ABX3 type perovskite; wherein, A is any one or a combination of at least two of cesium ions, rubidium ions, methylamino groups, and formamidinium groups; B is lead ions and / or tin ions; and X is any one or a combination of at least two of bromide ions, iodide ions, and chloride ions.

8. The UV-curable perovskite solar cell according to claim 1, characterized in that, The electron transport layer includes one of the following: metal oxides and organic materials; Metal oxides include TiO2, SnO2, and CeO. x One of them; Organic materials include one of PCBM and in-situ cyclized polyacrylonitrile.

9. The UV-curable perovskite solar cell according to claim 1, characterized in that, The electrode includes one of a back electrode and a transparent conductive electrode; The back electrode includes one of the following: a metal electrode, a carbon-based electrode, and a double-layer metal electrode; Transparent conductive electrodes include one of the following: TCOs, metal mesh / nanowires, and composite structures.

10. A method for preparing a UV-curable perovskite solar cell as described in claim 1, characterized in that, Includes the following steps: S1. Conductive substrate pretreatment; S2. Prepare a hole transport layer on a conductive substrate; S3. Spin-coat the perovskite light-absorbing layer precursor solution onto the hole transport layer, and anneal the solution to prepare the perovskite light-absorbing layer. S4. Spin-coat the composite modification layer solution onto the perovskite light-absorbing layer to prepare a single-layer nanosheet-epoxy acrylate composite modification layer; S5. Deposit an electron transport layer on a single-layer nanosheet-epoxy acrylate composite modification layer; S6. Electrodes are fabricated on the electron transport layer to obtain a perovskite solar cell.

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