Method for improving tensile property of organic photovoltaic active layer based on chlorinated plastic and application

Abstract

The invention discloses a method for improving the tensile property of an organic photovoltaic active layer based on chlorinated plastic and application. Introducing chlorinated plastic as a function regulator into the donor-acceptor blend to obtain an active layer solution, spin-coating the solution on the surface of the PSS layer glass substrate, and after spin-coating, performing thermal annealing treatment to form an organic photovoltaic active layer film, the chlorinated plastic accounting for 5-50% of the total mass of the organic photovoltaic material. The prepared organic photovoltaic active layer film can be further used for constructing a solar cell, and through modification of the chlorinated plastic on the active layer, the microstructure of the active layer can be effectively regulated and controlled and the interaction force between molecules can be enhanced, so that collaborative optimization of mechanical properties and photoelectric properties is realized. According to the method, the tensile flexibility of the high-efficiency organic solar cell can be improved, the photoelectric conversion efficiency of the high-efficiency organic solar cell can be maintained and even improved as much as possible, and the method has remarkable technical innovation and application and popularization value.

Description

Technical Field

[0001] This invention belongs to the field of photovoltaic device fabrication technology, specifically relating to a method and application for improving the tensile properties of organic photovoltaic active layers based on chlorinated plastics. Background Technology

[0002] Organic solar cells (OSCs) have become highly promising next-generation optoelectronic devices due to their flexibility, lightweight, and low cost. With the increasing demand for flexible electronic products such as wearable devices, developing organic photovoltaic thin films with excellent stretchability has become a key direction for improving the overall performance of these devices. However, current mainstream high-performance OSC devices typically employ blends of polymer donors and small molecule acceptors. While these systems offer high photoelectric conversion efficiency, they generally suffer from inherent defects such as insufficient mechanical strength and low elongation at break (crack initiation strain is typically less than 10%), severely limiting their practical application value in flexible applications.

[0003] Current technologies primarily focus on improving the mechanical properties of thin films by introducing elastomers or constructing dynamic covalent networks. For example, attempts are made to use all-polymer blends such as poly(3-hexylthiophene) (P3HT): polyethylene terephthalate (PET), and poly[2,6-di(2-ethylhexyl)-4,8-bis(2-ethylhexyl)-benzo[1,2-b:4,5-b']thiadiene]-2,6-diyl: poly(4,9-dithieno[3,2-b:5,6-b']diazathane]; or by introducing elastomers and crosslinking agents such as polyurethane (PU), styrene-ethylene-butadiene-styrene (SEBS), polydimethylsiloxane (PDMS), chloroprene rubber (CR), and 2,6-bis(4-azidobenzylene)cyclohexanone. While these strategies can enhance the self-healing ability and tensile recovery of the active layer to some extent through physical or chemical means, they are often accompanied by a significant decrease in photoelectric conversion efficiency.

[0004] Therefore, there is an urgent need for a new method that can significantly improve the stretching properties of the active layer without significantly reducing the photoelectric conversion efficiency. Summary of the Invention

[0005] To address the current technical bottleneck of balancing photoelectric conversion efficiency and mechanical tensile properties in organic photovoltaic devices, the present invention aims to provide a method and application for improving the tensile properties of the active layer of organic photovoltaics based on chlorinated plastics.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A method for improving the tensile properties of the active layer of an organic photovoltaic based on chlorinated plastics involves adding chlorinated plastics as a functional additive to an organic photovoltaic material composed of electron donor and electron acceptor materials, wherein the chlorinated plastics account for 5%-50% of the total mass of the organic photovoltaic material; the plastics include chlorinated polypropylene, chlorinated polyvinyl chloride, chlorinated nitrile rubber, chlorinated polyolefin, chlorinated polystyrene, chlorinated polyether, chlorinated polyether ether ketone, chlorinated polyacrylate, chlorinated polyimide, and chlorinated polyamide.

[0007] Furthermore, the electron donor materials include poly(3-hexylthiophene), polythiophene-benzodithiophene, polydithiophene-benzodithiophene, PM6, D18, PBDB-T-2F, PTB7-Th, polycarbazole, polyfluorene, poly(p-phenyleneethylene), poly(arylethyleneethylene), poly(p-phenylene), poly(aryl), porphyrins, and phthalocyanines.

[0008] Furthermore, the electron acceptor material includes methyl [6,6]-phenyl-C61-butyrate, methyl [6,6]-phenyl-C71-butyrate, perylene imide derivatives, naphthalene imide derivatives, BTP-eC9, L8-BO, Y6, Y6-BO, Y14, A-1, N3, SMA1, IT-4F, and ITIC.

[0009] Specifically, chlorinated plastics and organic photovoltaic materials are first dissolved separately in an organic solvent, mixed and stirred at 30~70℃ for 3-5 hours to obtain an active layer solution. This solution is then spin-coated onto the surface of a PSS layer glass substrate. After spin-coating, a heat annealing treatment is performed to form an organic photovoltaic active layer film.

[0010] Furthermore, the organic solvent is one or more of chloroform, chlorobenzene, dichlorobenzene, trichlorobenzene, toluene, xylene, tetrahydrofuran, or N,N-dimethylformamide.

[0011] Furthermore, the temperature of the heat annealing treatment is 80-200℃, and the time is 10-30 minutes.

[0012] A stretchable organic photovoltaic active layer film, wherein the organic photovoltaic active layer film is prepared by the above method.

[0013] Furthermore, the thickness of the organic photovoltaic active layer film is 30-500 nm.

[0014] A solar cell device, wherein the solar cell has a forward-facing device structure, comprising, from bottom to top, a conductive substrate, a hole transport layer, an active layer, an electron transport layer, and a metal electrode; or has an inverted device structure, comprising, from bottom to top, a conductive substrate, an electron transport layer, an active layer, a hole transport layer, and a metal electrode, wherein the active layer solution is deposited onto the surface of the hole transport layer or the electron transport layer to form a blended active layer.

[0015] Furthermore, the deposition method includes one or more of spin coating, blade coating, and printing.

[0016] In terms of device structure, the present invention uses a conductive substrate, which is selected from ITO thin film, graphene thin film, carbon nanotube thin film, metal nanowire thin film or conductive polymer thin film; preferably, the conductive substrate is ITO thin film or metal nanowire thin film.

[0017] Regarding the selection of electrode materials, the metal electrode materials described in this invention include, but are not limited to, one of gold (Au), silver (Ag), copper (Cu), aluminum (Al), calcium (Ca), nickel (Ni), zinc (Zn), titanium (Ti), gallium (Ga), or other alloys.

[0018] Regarding the selection of functional layers, this invention preferentially uses 2PACz as the hole transport layer, with a thickness ranging from 20 nm to 70 nm; it also preferably uses PDINN or PNDIT-F3N as the electron transport layer, with a thickness ranging from 10 nm to 40 nm. Furthermore, this invention preferably uses Ag or liquid metal EGaIn as the metal electrode, with a thickness ranging from 100 nm to 300 nm.

[0019] This invention significantly improves the photoelectric conversion performance of organic photovoltaic films at low concentrations by introducing a chlorinated plastic modifier, and effectively optimizes the compatibility of the donor-acceptor interface. Simultaneously, by appropriately increasing the content of this component, the tensile strength and flexibility of the film can be significantly enhanced. Furthermore, the chlorinated plastic is inexpensive and economical, effectively reducing preparation costs, and its molecular structure is highly compatible with conjugated polymers, making it less likely to disrupt the photoelectric transmission channels within the active layer.

[0020] In addition to possessing excellent mechanical properties, the chlorinated plastic modification component of this invention must also be selected in a way that matches the donor and acceptor materials in order to achieve a synergistic improvement in the mechanical and photoelectric properties of the film.

[0021] This invention also addresses the problem that the active layer morphology of current bulk heterojunction (BHJ) organic solar cells is complex, which can easily lead to mechanical enhancement failure or damage to charge transport channels. This invention reveals two core mechanisms for enhancing mechanical properties: interface compatibility regulation and intermolecular interaction regulation.

[0022] Specifically, in the BHJ active layer system composed of conjugated polymer donors and small molecule acceptors, the chlorine substituents in the chlorinated plastic molecular chain can form non-covalent interactions with the thiophene units and carbonyl groups of the donor and acceptor materials (dipole-dipole interactions between C-Cl dipoles and carbonyl groups (C=O), sulfur atoms (S), etc.). This interaction promotes the formation of a high-density dynamic entanglement structure between the donor-acceptor interpenetrating network and the chlorinated plastic molecular chain, thereby significantly improving the tensile toughness and crack propagation resistance of the film. The effectiveness of this process depends not only on the matching degree of solubility parameters between the host material and the chlorinated plastic, but also on the complementarity of molecular structures (such as the degree of chlorination, chain segment length, and spatial adaptability of the conjugated polymer side chains). Only when the three form a thermodynamically stable blend system and the phase separation scale is controlled within the optimal charge transport range can effective mechanical reinforcement be achieved while avoiding damage to the charge separation and transport channels at the donor-acceptor interface.

[0023] Furthermore, this invention introduces a hydrogen bond-mediated dynamic mechanical reinforcement mechanism. In the chloroalkyl side chain of the chlorinated plastic, the β-H adjacent to the chlorine atom (which is partially positively charged due to the strong electron-withdrawing effect of Cl, acting as a hydrogen bond donor) can form intermolecular hydrogen bonds with the carbonyl oxygen (which is partially negatively charged, acting as a hydrogen bond acceptor) in the donor-acceptor material molecule. In this process, the dynamic reversibility of hydrogen bonds drives the re-optimization of the molecular chain arrangement: the chlorinated plastic molecular chains are orderly interwoven in the donor-acceptor interpenetrating network, forming dynamically reversible cross-linking-like nodes. These nodes can temporarily break under tensile stress to dissipate energy, and after unloading, they can restore the network structure through hydrogen bond recombination. This not only avoids brittle fracture of the film but also constructs a flexible support framework for the active layer, while optimizing the mechanical response and elastic recovery characteristics of the film.

[0024] Furthermore, this invention utilizes Lewis acid-base interactions to enhance the synergistic effect between chlorinated plastics and the host material, precisely controlling the phase separation structure and mechanical stability. Specifically, in chlorinated plastic molecules, sp atoms carry a partial positive charge due to the strong electron-withdrawing effect of Cl atoms. 3 Hybridized C atoms (Lewis acid sites) can form specific Lewis acid-base complexes with nitrogen atoms (containing lone pairs of electrons, Lewis base sites) of carbazole units and sulfur atoms (containing lone pairs of electrons, Lewis base sites) of benzodithiophene units in donor materials. This interaction can further refine the donor-acceptor phase separation scale, improve the interfacial compatibility and continuity of the phase region, and enhance intermolecular binding forces, preventing phase delamination during stretching. For example, the active layer system composed of polymer donors such as PM6 / D18 and small molecule acceptors such as BTP-eC9 / L8-BO achieves significant improvement in mechanical properties without compromising photoelectric conversion efficiency (PCE) through the synergistic regulation of non-covalent entanglement, hydrogen bonding, and Lewis acid-base complexation.

[0025] The structural formula of the organic photovoltaic polymer donor material involved is as follows:

[0026]

[0027]

[0028] The structural formula of the organic photovoltaic small molecule acceptor material involved is as follows:

[0029] The structural formula of the chlorinated plastics involved is as follows:

[0030] The present invention has the following beneficial effects: (1) This invention introduces chlorinated plastics with chlorine substituents of specific molecular structures as functional regulators into the donor-acceptor blended active layer. Compared with the active layer without chlorinated plastics, the introduction of an appropriate amount of chlorinated plastics significantly improves the structural stability, mechanical ductility, and charge transport efficiency of the active layer. This effectively optimizes the tensile ductility of the active layer and reduces the bulk elastic modulus of the material. While improving mechanical compliance, it further precisely controls the compatibility and aggregated state structure of the donor-acceptor interface, thereby achieving synergistic optimization of conductivity and photovoltaic performance. This provides key technical support for the application of organic solar cells in emerging application scenarios such as flexible wearable and rollable devices. In addition, the method for preparing organic photovoltaic thin films containing chlorinated plastics proposed in this invention is also applicable to various organic optoelectronic devices (including but not limited to organic solar cells, organic light-emitting diodes, organic thin-film transistors, and organic photodetectors), and can significantly improve the long-term stability of the devices.

[0031] (2) This invention also found that the photovoltaic performance of chlorinated plastic modified films exhibits a clear structure-property relationship with the doping amount: that is, as the doping amount of chlorinated plastic increases, the photoelectric conversion efficiency of the device shows a change characteristic of first increasing and then decreasing. Although chlorinated plastic itself does not have photovoltaic activity, the chlorine substituents in its molecular backbone can produce a synergistic effect with the conjugated system, so that a small amount of doping can improve the interfacial compatibility of the donor-acceptor blend system, effectively suppress excessive phase separation and promote the orderly stacking of molecular chains. This optimization of the microstructure not only improves the mechanical stability of the device, but also avoids the loss of photoelectric performance caused by mechanical stress.

[0032] (3) Compared with traditional tensile property modification methods, this invention successfully achieves the dual goals of enhancing mechanical properties and maintaining photoelectric properties through precise control of chlorinated plastics. It cleverly solves the contradiction that mechanical property improvement in traditional modification strategies often comes at the cost of sacrificing photoelectric properties, while simplifying the preparation process and possessing significant technological innovation and application promotion value. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the structure of an organic solar cell in a positive orientation device according to an embodiment of the present invention.

[0034] Figure 2 The stress-strain curves of Examples 1-4 and Comparative Example 1 obtained by the underwater thin film test method are shown.

[0035] Figure 3 The bar chart shows the crack initiation strain corresponding to different CPP ratios in the total mass of the active layer (D18:L8-BO) in Example 5.

[0036] Figure 4 JV curves of the organic solar cell devices prepared in Example 6 and Comparative Example 3; Figure 5 The efficiency-fill factor curves are for the organic solar cell devices prepared in Examples 7-10 and Comparative Example 4. Detailed Implementation

[0037] To make the content of this invention easier to understand, the technical solution of this invention will be further described below with reference to specific embodiments, but this invention is not limited thereto.

[0038] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, all reagents and materials used in the following examples are commercially available products.

[0039] In this embodiment of the invention, the structure of the prepared solar cell device is as follows: Figure 1 As shown, a positively positioned device configuration is used. From bottom to top, the layers are a conductive substrate, a hole transport layer, an active layer, an electron transport layer, and a metal electrode; the photodetector also uses the same diode structure.

[0040] The chlorinated polypropylene (CPP) used in the following examples was purchased from RHAWN, with product batch number RH841204, CAS number 68442-33-1, and purity AR.

[0041] The mechanical properties of the films were characterized using the film-on-water (FOW) and film-on-elastic (FOE) methods, as detailed in the following examples: In the FOW test, the first size was 2×2cm. 2The glass substrate was ultrasonically cleaned sequentially with isopropanol, detergent dilution, deionized water, acetone, and isopropanol (each step for 15 min), followed by nitrogen purging to remove residual solvent. The cleaned glass substrate was then treated in a UV-Ozone cleaner for 20 min to enhance surface hydrophilicity. A poly(sodium styrenesulfonate) solution (PSS) dilution (PSS to deionized water volume ratio of 1:4) was prepared. This PSS dilution was spin-coated onto the glass substrate at 4500 rpm for 30 s, followed by annealing at 150°C for 20 min on a high-precision temperature-controlled hot plate. After annealing, the sample was transferred to a glove box under an inert argon atmosphere for cooling. The active layer solution prepared in the example was spin-coated onto the cooled PSS layer surface at 1000 rpm for 30 s. After spin coating, the film was placed on a high-precision temperature-controlled hot stage at 100℃ for 10 minutes for thermal annealing to form a dense and uniform active layer film. The film thickness was then measured multiple times using a profilometer, and the average value was recorded. The annealed active layer film was cut into multiple strips approximately 2cm x 5mm in length and width using a laser. The glass substrate was slowly immersed in water, allowing the active layer film to detach from the glass substrate and float on the water surface. The testing instrument was started for mechanical zeroing. The film was gently blown with a syringe to guide it to the PDMS fixture. Water was slowly added to the FOW water tank, raising the liquid level until the film was adsorbed onto the PDMS surface. A tensile zeroing operation was performed again before testing. After testing, the fixture was mechanically zeroed, and the PDMS surface was wiped with chloroform / ethanol for the next test. The stress-strain curves of the film were recorded using the FOW testing system, where the thickness of both the pure and hybrid films was approximately 200nm.

[0042] In the FOE test, the first step is to prepare a 1.5×1.5cm sample. 2 The glass slide was cleaned, and following the FOW test procedure described above, PSS and an active layer were spin-coated onto the glass substrate. Then, PDMS was cut into strips approximately 6 cm long and 2 cm wide and fixed onto a self-made stretching machine. The glass slide with the active layer spin-coated was adhered to the PDMS substrate and then immersed in deionized water for approximately 30 minutes. At this point, the PSS layer dissolved in the water, the glass substrate detached automatically, leaving only the active layer film on the PDMS substrate, thus achieving the transfer of the active layer film from the glass substrate to the PDMS substrate. The original length of the active layer film was measured using vernier calipers. Under real-time observation with a polarizing microscope, uniaxial tension was applied to the film until a fine crack appeared, and the tensile strain value at this point was recorded as the crack initiation strain.

[0043] Example 1

[0044] Weigh 2.8 mg of donor material PM6 (CAS: 1802013-83-7) and 3.36 mg of acceptor material BTP-eC9 (CAS: 2598965-39-8), and dissolve them in 369.2 μL of chloroform to obtain a mixed solution. Separately, dissolve 0.308 mg of CPP in 30.8 μL of chloroform. After stirring at room temperature for 30 min, add the CPP solution to the mixed solution (i.e., CPP accounts for 5% of the total mass of PM6 and BTP-eC9). Continue stirring at 50 °C for 4 h until the mixture is completely dissolved to obtain a homogeneous active layer solution. Spin-coat the active layer solution onto the surface of a glass substrate containing a PSS layer to prepare the active layer film (spin-coating method is the same as the steps in the FOW test). Figure 2 As shown, the fracture strain of the prepared active layer film is 5.5±0.5%, which is 34.17% higher than that of Comparative Example 1 without CPP (fracture strain of about 4.1%).

[0045] Example 2

[0046] 2.8 mg of donor material PM6 and 3.36 mg of acceptor material BTP-eC9 were weighed and dissolved in 338.4 μL of chloroform to obtain a mixed solution. Separately, 0.616 mg of CPP was dissolved in 61.6 μL of chloroform. After stirring at room temperature for 30 min, the CPP solution was added to the mixed solution (i.e., CPP accounts for 10% of the total mass of PM6 + BTP-eC9). The mixture was stirred continuously at 50 °C for 4 h until it was completely dissolved to obtain a homogeneous active layer solution. The active layer solution was spin-coated onto the surface of a glass substrate containing a PSS layer to prepare the active layer film. Figure 2 As shown, the fracture strain of the prepared active layer film is 6.9±0.5%, which is 68% higher than that of Comparative Example 1 (fracture strain of about 4.1%) without the addition of CPP.

[0047] Example 3

[0048] 2.8 mg of donor material PM6 and 3.36 mg of acceptor material BTP-eC9 were weighed and dissolved in 276.8 μL of chloroform to obtain a mixed solution. Separately, 1.232 mg of CPP was dissolved in 123.2 μL of chloroform. After stirring at room temperature for 30 min, the CPP solution was added to the mixed solution (i.e., CPP accounts for 20% of the total mass of PM6 + BTP-eC9). The mixture was stirred continuously at 50 °C for 4 h until it was completely dissolved to obtain a homogeneous active layer solution. The active layer solution was spin-coated onto the surface of a glass substrate containing a PSS layer to prepare the active layer film. Figure 2 As shown, the fracture strain of the prepared active layer film is 8.7±0.5%, which is 112% higher than that of Comparative Example 1 without CPP (fracture strain of about 4.1%).

[0049] Example 4

[0050] 2.8 mg of donor material PM6 and 3.36 mg of acceptor material BTP-eC9 were weighed and dissolved in 92 μL of chloroform to obtain a mixed solution. Separately, 3.08 mg of CPP was dissolved in 308 μL of chloroform. After stirring at room temperature for 30 min, the CPP solution was added to the mixed solution (i.e., CPP accounts for 50% of the total mass of PM6 + BTP-eC9). The mixture was stirred continuously at 50 °C for 4 h until it was completely dissolved to obtain a homogeneous active layer solution. The active layer solution was spin-coated onto the surface of a glass substrate containing a PSS layer to prepare the active layer film. Figure 2 As shown, the fracture strain of the prepared active layer film was 14.8 ± 0.5%, which is 260% higher than that of Comparative Example 1 (fracture strain of approximately 4.1%) without CPP. Furthermore, as shown in Examples 1-4, the stretchability (ductility) of the active layer of the organic solar cell is significantly enhanced with increasing CPP content. This is mainly attributed to the enhanced interfacial compatibility network constructed by CPP within the active layer, effectively suppressing the propagation of microcracks.

[0051] Example 5

[0052] 2.0 mg of donor material D18 (CAS: 2433725-54-1) and 2.4 mg of acceptor material L8-BO (CAS: 2668341-40-8) were weighed and mixed, then dissolved in 263.7 μL, 241.7 μL, 197.7 μL, and 65.7 μL of chloroform to obtain mixed solutions. Separately, different masses of CPP (0.22 mg, 0.44 mg, 0.88 mg, and 2.2 mg) were dissolved in 22 μL, 44 μL, 88 μL, and 220 μL of chloroform, respectively. After stirring at room temperature for 30 min, these solutions were added to the mixed solutions, with the corresponding CPP percentages of the total D18+L8-BO mass being 5%, 10%, 20%, and 50%, respectively. The mixture was stirred continuously at 50 °C for 4 h until completely dissolved to obtain a homogeneous active layer solution. The active layer solution was then spin-coated onto the surface of a glass substrate containing a PSS layer to prepare the active layer film. Figure 3 As shown, Comparative Example 2, without added CPP, exhibited microcracks under extremely low strain, with a crack initiation strain (COS) of only 1.5 ± 0.5%. However, under the same tensile conditions, no cracks were observed on the surface of the active layer when the CPP content reached 50%. With increasing CPP content, the elastic modulus of the active layer decreased, while the fracture strain and toughness were effectively improved, thus significantly enhancing the tensile properties of the D18 / L8-BO active layer film.

[0053] Example 6

[0054] Donor material D18 2 mg and acceptor materials BTP-eC9 2.2 mg and L8-BO 0.4 mg were dissolved in 262.7 μL of chloroform to obtain a mixture solution; separately, CPP 0.23 mg was dissolved in 23 μL of chloroform, stirred at room temperature for 30 min, and then added to the mixture solution (i.e., CPP accounts for 5% of the total mass of the ternary mixture). The mixture was stirred continuously at 50 °C for 4 h until the mixture was completely dissolved to obtain a homogeneous active layer solution.

[0055] The active layer solution prepared in this embodiment is further used to construct an organic solar cell device, which adopts an upright device structure. The specific preparation method is as follows: (1) The ITO glass substrate, after initial wiping and cleaning, was ultrasonically cleaned sequentially with isopropanol, diluted detergent, deionized water, acetone and isopropanol, and then the residual solvent on the surface was dried with nitrogen. The ITO glass substrate was then treated in a UVO cleaner for 25 min. 50 μL of 2PACz (CAS: 20999-38-6) anhydrous ethanol solution (concentration of 0.3 mg / mL) was spin-coated onto the treated ITO surface at 4000 r / min for 30 s. The sample was then transferred to a high-precision temperature-controlled hot plate and annealed at 150 °C for 20 min to obtain a dry and dense hole transport layer film (thickness of 40 nm), and then quickly transferred to a glove box filled with argon.

[0056] (2) Spin-coat the obtained active layer solution onto the surface of the 2PACz layer obtained in step (1) with spin-coating parameters of 30 μL, 1500 r / min, and 40 s. After spin-coating, place it on a hot stage at 100 ℃ for 10 min for heat annealing to promote film crystallization and phase separation.

[0057] (3) Spin-coat 80 μL of a 0.5 mg / mL polydiimide naphthalimide (PDINN, CAS: 1020180-01-1) methanol solution onto the surface of the active layer obtained in step (2) at a spin-coating speed of 3000 r / min for 40 s. Place the prepared composite thin film substrate (40 nm thick) into a vacuum evaporation apparatus and deposit a 100 nm thick silver metal electrode on the PDINN surface to obtain the organic solar cell device.

[0058] Under standard test conditions (AM1.5G, 100mW cm⁻¹) -2 The device performance was tested under the following conditions. The results show that the open-circuit voltage (Voc) is 0.87 ± 0.008 V, and the short-circuit current density (Jsc) is 28.01 ± 0.11 mA cm⁻¹. -2The fill factor (FF) is 81.2 ± 0.54%. Compared to the control group without CPP (Comparative Example 3), the power conversion efficiency (PCE) of the device in this embodiment is significantly improved to 20.01 ± 0.14%. Figure 4 As shown.

[0059] Example 7

[0060] 2.8 mg of donor material PM6 and 3.36 mg of acceptor material BTP-eC9 were dissolved in 369.2 μL of chloroform to obtain a mixed solution. Separately, 0.308 mg of CPP was dissolved in 30.8 μL of chloroform. After stirring at room temperature for 30 min, the solution was added to the mixed solution (i.e., CPP accounted for 5% of the total mass of the mixture). The mixture was stirred continuously at 50 °C for 4 h until it was completely dissolved to obtain a homogeneous active layer solution. The obtained active layer solution was used to construct an organic solar cell device, following the same steps as in Example 6.

[0061] Under standard illumination conditions (AM1.5G, 100mW cm⁻¹) -2 The device was tested. The measured Voc was 0.85 ± 0.05 V, and the Jsc was 27.8 ± 0.4 mA cm⁻¹. -2 The FF was 77.3 ± 1.1%. Compared with the control group (Comparative Example 4) without CPP, the PCE of the device in this embodiment was improved to 18.37 ± 0.20%. Figure 5 As shown.

[0062] Example 8

[0063] 2.8 mg of donor material PM6 and 3.36 mg of acceptor material BTP-eC9 were dissolved in 338.4 μL of chloroform to obtain a mixture solution. Separately, 0.616 mg of CPP was dissolved in 61.6 μL of chloroform. After stirring at room temperature for 30 min, the mixture was added to the mixture solution (i.e., CPP accounted for 10% of the total mass of the mixture). The mixture was stirred continuously at 50 °C for 4 h until it was completely dissolved to obtain a homogeneous active layer solution. The obtained active layer solution was used to construct an organic solar cell device, following the same steps as in Example 6.

[0064] Under standard test conditions (AM1.5G, 100mW cm⁻¹) -2 The measured Voc of the device was 0.85±0.05V, and Jsc was 27.4±0.4mA cm. -2 The FF was 78.9±1.1%. Compared with the control group without CPP (Comparative Example 4), the PCE of the device in this embodiment reached 18.51±0.05%.

[0065] Example 9

[0066] 2.8 mg of donor material PM6 and 3.36 mg of acceptor material BTP-eC9 were dissolved in 276.8 μL of chloroform to obtain a mixture solution. Separately, 1.232 mg of CPP was dissolved in 123.2 μL of chloroform. After stirring at room temperature for 30 min, the mixture was added to the mixture solution (i.e., CPP accounted for 20% of the total mass of the mixture). The mixture was stirred continuously at 50 °C for 4 h until it was completely dissolved to obtain a homogeneous active layer solution. The obtained active layer solution was used to construct an organic solar cell device, following the same steps as in Example 6.

[0067] Under standard test conditions (AM1.5G, 100mW cm⁻¹) -2 The measured Voc of the device was 0.85±0.05V, and Jsc was 26.5±0.4mA cm. -2 The FF was 75.8 ± 1.1%. At this point, the device's PCE was 17.20 ± 0.05%. Compared to the control group (Comparative Example 4) without CPP, this device maintained a relative stability of 95.3% in PCE. Figure 5 As shown.

[0068] Example 10

[0069] 2.8 mg of donor material PM6 and 3.36 mg of acceptor material BTP-eC9 were dissolved in 92 μL of chloroform to obtain a mixture solution. Separately, 3.08 mg of CPP was dissolved in 308 μL of chloroform. After stirring at room temperature for 30 min, the mixture was added to the mixture solution (i.e., CPP accounted for 50% of the total mass of the mixture). The mixture was stirred continuously at 50 °C for 4 h until it was completely dissolved to obtain a homogeneous active layer solution. The obtained active layer solution was used to construct an organic solar cell device, following the same steps as in Example 6.

[0070] Under standard test conditions (AM1.5G, 100mW cm⁻¹) -2 The measured Voc of the device was 0.85±0.05V, and Jsc was 23.9±0.4mA cm. -2 The FF was 68.2 ± 1.1%. At this point, the device's PCE decreased to 13.87 ± 0.05%. Compared to the control group (Comparative Example 4) without CPP, the device's PCE remained at only 76.9%. Figure 5 As shown, this indicates that when the CPP content is too high, although it may improve charge transport, the excessive additives disrupt the phase separation morphology between the donor and acceptor, leading to an increase in nonradiative recombination, thereby reducing the overall photoelectric conversion efficiency of the device.

[0071] Therefore, as the CPP content increases, the device performance shows a trend of first increasing and then decreasing.

[0072] Comparative Example 1 The difference between this comparative example and Example 1 is that CPP was not added. 2.8 mg of donor material PM6 and 3.36 mg of acceptor material BTP-eC9 were dissolved in 400 μL of chloroform, and the mixture was stirred continuously at 50°C for 4 hours until completely dissolved to obtain a homogeneous active layer solution. The tensile strain of the obtained active layer film was determined to be 4.2 ± 0.5% using the floating film over water (FOW) method. Figure 2 (As shown).

[0073] Comparative Example 2 The difference between this comparative example and Example 5 is that CPP was not added. Instead, 2.0 mg of donor material D18 and 2.4 mg of acceptor material L8-BO were dissolved in 285.7 μL of chloroform, and the mixture was stirred continuously at 50°C for 4 hours until completely dissolved to obtain a homogeneous active layer solution. Experimental results show that the crack initiation strain of the active layer film in this system is 2.1 ± 0.5% (e.g., ...). Figure 3 (As shown).

[0074] Comparative Example 3 The difference between this comparative example and Example 6 is that CPP was not added. Donor material D18 2.0 mg, receptor material BTP-eC9 2.2 mg and receptor material L8-BO 0.4 mg were dissolved in 285.7 μL of chloroform and stirred continuously at 50°C for 4 h until the mixture was completely dissolved to obtain a homogeneous active layer solution.

[0075] The active layer film is prepared by spin-coating the active layer solution onto the surface of a glass substrate containing a PSS layer. The fracture strain of the prepared active layer film is 3.8 ± 0.3% according to the Forward-Facing Wood (FOW) test.

[0076] The resulting active layer solution was used to construct an organic solar cell device, following the same steps as in Example 6. Under standard test conditions (AM1.5G, 100mW cm⁻¹), -2 The device performance was tested, and the measured Voc was 0.86±0.007V, and Jsc was 28.03±0.33mA cm⁻¹. -2 The FF was 79.9±1.43%, and the PCE was 19.44±0.25% (e.g. Figure 4 (As shown).

[0077] Comparative Example 4 2.8 mg of donor material PM6 and 3.36 mg of acceptor material BTP-eC9 were dissolved in 400 μL of chloroform and stirred continuously at 50 °C for 4 h until the mixture was completely dissolved to obtain a homogeneous active layer solution. The construction method of the organic solar cell device is the same as in Example 6. Under standard test conditions (AM1.5G, 100mW cm⁻¹), -2The device performance was tested, and the measured Voc was 0.85±0.01V, and Jsc was 28.1±0.22mA cm⁻¹. -2 The FF was 75.4 ± 1.6%, and the PCE was 18.04 ± 0.20% (e.g. Figure 5 (As shown).

[0078] Comparative Example 5 A mixture solution was prepared by dissolving 2.8 mg of donor material PM6 and 3.36 mg of acceptor material BTP-eC9 in 215.2 μL of chloroform; a polymerization degree of approximately 9.5 x 10⁻⁶ was also prepared. 4 1.848 mg of polydimethylsiloxane (PDMS, CAS: 9016-00-6) with a fracture strain as high as 600% was dissolved in 184.8 μL of chloroform (i.e., PDMS accounted for 30% of the total mass of the mixture). After stirring at room temperature for 50 min, the PDMS solution was added to the mixture solution and stirred at 50 °C for 4 h until the mixture was completely dissolved to obtain a homogeneous active layer solution.

[0079] The active layer film is prepared by spin-coating the active layer solution onto the surface of a glass substrate containing a PSS layer. The fracture strain of the prepared active layer film is 14.40% as determined by FOW (Formula-Oxide-Wood) testing.

[0080] The resulting active layer solution was used to construct an organic solar cell device, following the same steps as in Example 6. Under standard test conditions (AM1.5G, 100mW cm⁻¹), -2 The device performance was tested, and the measured Voc was 0.76±0.08V, and Jsc was 27.83±0.4mA cm. -2 The FF was 68.10±0.09%, and the PCE was 12.03±0.70%.

[0081] Comparative Example 6 The donor material, poly[N-9'-heptadecyl-2,7-carbazole-alt-5,5-(4',7'-di-2-thienyl-2',1',3'-benzothiadiazole)] (PCDTBT, CAS: 958261-50-2), and the small molecule acceptor, methyl [6,6]-phenyl-C61-butyrate (PC61BM, CAS: 160848-22-6), were dissolved in 92 μL of chloroform to obtain a mixture solution. Separately, 0.308 mg of CPP was dissolved in 308 μL of chloroform. After stirring at room temperature for 30 min, the mixture was added to the mixture solution (i.e., CPP accounted for 5% of the total mass of the mixture). The mixture was stirred at 50 °C for 4 h until it was completely dissolved to obtain a homogeneous active layer solution.

[0082] The active layer film is prepared by spin-coating the active layer solution onto the surface of a glass substrate containing a PSS layer. The fracture strain of the prepared active layer film is 4.6% as determined by FOW (Formula-Oxide-Wood) testing.

[0083] The resulting active layer solution was used to construct an organic solar cell device, following the same steps as in Example 6. Under standard test conditions (AM1.5G, 100mW cm⁻¹), -2 The device performance was tested under these conditions, and the measured Voc was 0.73 ± 0.06 V, and Jsc was 13.90 ± 0.4 mA cm⁻¹. -2 The FF was 38.6±0.6%, and the PCE was 3.92±0.60%.

[0084] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for improving the tensile properties of an organic photovoltaic active layer based on chlorinated plastics, characterized in that: Chlorinated plastics are added as functional additives to organic photovoltaic materials composed of electron donor materials and electron acceptor materials, wherein the chlorinated plastics account for 5%-50% of the total mass of the organic photovoltaic materials; the plastics include chlorinated polypropylene, chlorinated polyvinyl chloride, chlorinated nitrile rubber, chlorinated polyolefin, chlorinated polystyrene, chlorinated polyether, chlorinated polyether ether ketone, chlorinated polyacrylate, chlorinated polyimide, and chlorinated polyamide.

2. The method according to claim 1, characterized in that: The electron donor materials include poly(3-hexylthiophene), polythiophene-benzodithiophene, polydithiophene-benzodithiophene, PM6, D18, PBDB-T-2F, PTB7-Th, polycarbazole, polyfluorene, poly(p-phenyleneethylene), poly(arylethyleneethylene), poly(p-phenylene), poly(aryl), porphyrins, and phthalocyanines.

3. The method according to claim 1, characterized in that: The electron acceptor materials include methyl [6,6]-phenyl-C61-butyrate, methyl [6,6]-phenyl-C71-butyrate, perylene imide derivatives, naphthalene imide derivatives, BTP-eC9, L8-BO, Y6, Y6-BO, Y14, A-1, N3, SMA1, IT-4F, and ITIC.

4. The method according to claim 1, characterized in that: Specifically, chlorinated plastics and organic photovoltaic materials are first dissolved separately in an organic solvent, mixed, and stirred at 30~70℃ for 3-5 hours to obtain an active layer solution. This solution is then spin-coated onto the surface of a PSS layer glass substrate. After spin-coating, a heat annealing treatment is performed to form an organic photovoltaic active layer film.

5. The method according to claim 4, characterized in that: The organic solvent is one or more of chloroform, chlorobenzene, dichlorobenzene, trichlorobenzene, toluene, xylene, tetrahydrofuran, or N,N-dimethylformamide.

6. The method according to claim 4, characterized in that: The heat annealing process is performed at a temperature of 80-200℃ for 10-30 minutes.

7. A stretchable organic photovoltaic active layer thin film, characterized in that: The organic photovoltaic active layer film is prepared by the method described in any one of claims 1 to 6.

8. The organic photovoltaic active layer thin film according to claim 7, characterized in that: The thickness of the organic photovoltaic active layer film is 30-500 nm.

9. A solar cell device, characterized in that: The solar cell has a forward-facing device structure, consisting of a conductive substrate, a hole transport layer, an active layer, an electron transport layer, and a metal electrode, arranged from bottom to top; or it has an inverted device structure, consisting of a conductive substrate, an electron transport layer, an active layer, a hole transport layer, and a metal electrode, arranged from bottom to top, wherein the active layer solution described in claim 4 is deposited onto the surface of the hole transport layer or the electron transport layer to form a blended active layer.

10. The solar cell device according to claim 9, characterized in that: The deposition method includes one or more of spin coating, blade coating, and printing.

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