Flexible single-component block polymer-based material as well as preparation method and application of flexible single-component block polymer-based material

Abstract

The invention relates to a block polymer material based on a flexible single component as well as a preparation method and application thereof. The molecular structure of the polymer material is as follows: # imgabs0 #: firstly synthesizing a BDT polymer donor fragment and a polymer acceptor material PYHT fragment; and transferring the polymer donor material PM6 fragment to the polymer acceptor material PYHT fragment by using an injector, and continuing polymerization to obtain the material. As an optical active layer material, the material can realize high-efficiency photoelectric conversion of a device, and meanwhile, the mechanical property of the active layer material is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of organic solar cells, and particularly relates to the synthesis of a class of BDT-type polymer donors and Y-series acceptor flexible single-component block polymer materials and their application in organic solar cell devices. Background Art

[0002] Organic photovoltaics (OPV) is an emerging technology that is feasible for large-scale roll-to-roll manufacturing and has the advantages of light weight, high flexibility and low cost. At the same time, it has the potential for development into flexible wearables and can be applied to more scenarios such as life and industrial production. Among them, the donor and acceptor of the single-component organic solar cell material are connected by covalent bonds, which can inhibit the gradual demixing between the donor and the acceptor, provide a long-term stable nanophase morphology, and have great application prospects. However, the current single-component block polymer organic solar cell materials have rigid connections in their polymer chains and lack good mechanical properties, which often makes it difficult to maintain stability under external forces. Therefore, solving the problem of rigid polymer chains is an important step towards industrial functionalization. The Enhanced Intramolecular Hole Transfer in Block Copolymer Enables>15% and Operational Stable Single-Material-Organic Solar Cells reported by Professor Yuan Jianyu's team at Soochow University in Advanced Materials is the single-component block polymer with the highest photoelectric conversion efficiency, with a PCE of 15.02%; the Towards efficient and stable organic solar cells: fixing the morphology problem in block copolymer active layers with synergistic strategies supported by interpretable machine learning reported by Professor Yan Han's team at Xi'an Jiaotong University in Energy & Environmental Science added small molecule additives to the single-component block polymer for regulation, and the photoelectric conversion efficiency reached 15.9%. At present, whether the block polymer is regulated by adding additives or not, its connecting chains are rigid and have poor mechanical flexibility, which poses a huge obstacle to industrial application. Summary of the invention

[0003] The purpose of the present invention is to provide a class of flexible single-component block polymer materials, preparation methods and applications in view of the problems existing in the prior art. This class of materials is a class of flexible single-component block polymer materials with BDT-type polymer donors and Y-series acceptors, that is, a flexible chain is introduced into the acceptor part of the single-component material, and the flexible chain replaces the rigid thiophene unit, so that the tensile properties of the polymer chain are better, and the problem of easy breakage due to rigid connection under external force is solved, and efficient organic solar cells can be obtained through simple solution processing.

[0004] The present invention discloses a class of flexible single-component block polymer materials having the following molecular structure:

[0005]

[0006] Wherein, X is a H atom or a halogen atom, R1 and R2 are alkyl chains, and a represents the length of the flexible chain.

[0007] The flexible single-component block polymer material described in the present invention also includes derivatives thereof.

[0008] The preparation method of a class of flexible single-component block polymer materials described in the present invention is as follows (taking PM6-b-PYIT as an example):

[0009] (1) Synthesis of BDT-type polymer donor fragments: The raw materials BDT-2F and BDD-2Br were polymerized in solvent toluene to obtain the polymer donor PM6 fragment.

[0010] (2) Synthesis of polymer receptor material PYHT fragment: The raw materials 2,5-bis(trimethyltinyl)thiophene, 1,6-bis(5-(trimethyltinyl)thiophene)hexyl and Y5-2Br were polymerized in solvent toluene to obtain the polymer receptor PYHT fragment.

[0011] (3) Synthesis of flexible single-component block polymer material PM6-b-PYHT: The obtained polymer donor material PM6 fragment was transferred to the reaction tube of the polymer acceptor material PYHT fragment by syringe, and the polymerization was continued to preliminarily obtain the flexible single-component block polymer material PM6-b-PYHT. It was precipitated with methanol, filtered, and extracted with solvents such as n-hexane, acetone, dichloromethane, and chloroform in turn, and then passed through a silica gel chromatography column, and finally concentrated, precipitated, and filtered to obtain the final product, the flexible single-component block polymer material PM6-b-PYHT.

[0012] Its molecular structure is as follows:

[0013]

[0014] The present invention discloses a class of flexible single-component block polymer materials used as photoactive layer materials in the preparation of polymer single-component organic solar devices.

[0015] Furthermore, the polymer single-component organic solar cell device described in the present invention comprises an indium tin oxide (ITO) conductive glass anode, an anode modification layer, a photoactive layer, a cathode modification layer, and a cathode. The anode modification layer is PEDOT / PSS (30nm); the cathode modification layer is F3N (30nm); the cathode is a deposited layer of Ag (100nm); and the active layer material is the flexible single-component material described in the present invention.

[0016] The present invention improves the tensile properties by modifying the connecting units of the polymer chain, and uses a flexible chain to replace the thiophene unit in the material to achieve the transition from rigid to flexible connection. Since only the receptor part is changed, the main part of the material does not change much and the synthesis process is not too complicated. At the same time, the connection of covalent bonds inside the material brings about improved stability and improved power generation performance. Most importantly, the introduction of flexible groups has greatly improved the mechanical properties of the material and has better resistance to external forces, which is of great practical significance for achieving the goal of large-area wearable. The introduction of flexible chain connections achieves better mechanical flexibility than the original rigid connection of thiophene groups.

[0017] Compared with the currently reported materials, the flexible single-component block polymer material of the present invention has the following characteristics: (1) the polymer donor material and the polymer acceptor material are connected by covalent bonds to achieve effective exciton dissociation and charge generation; (2) the donor and acceptor parts are covalently connected to one material, making the organic solar device easier to process; (3) because the donor and acceptor parts are covalently connected, the morphology of the active layer can be better resisted during the aging process of the device, and the device stability is better; (4) the acceptor part introduces a flexible group, and the single-component material has better mechanical properties than the original rigid material, and can be better used in the preparation of wearable organic solar cells. Therefore, this type of material is a type of single-component organic solar material with great development prospects and application potential.

[0018] The flexible single-component block polymer material of the present invention is used as a photoactive layer material to prepare a single-component organic solar device, thereby achieving efficient photoelectric conversion of the device and improving the mechanical properties of the active layer material. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 UV-visible absorption spectrum of PM6-b-PYIT solid film.

[0020] Figure 2 It is the UV-visible absorption spectrum of PM6-b-PYHT solid film of the present invention.

[0021] Figure 3 This is the cyclic voltammetry curve of PM6-b-PYIT solid film.

[0022] Figure 4 This is the cyclic voltammetry curve of the PM6-b-PYHT solid film of the present invention.

[0023] Figure 5 JV curve of PM6-b-PYIT single-component solar cell device.

[0024] Figure 6 This is the JV curve of the PM6-b-PYHT single-component solar cell device of the present invention.

[0025] Figure 7 This is the tensile stress-strain curve of PM6-b-PYIT film.

[0026] Figure 8 This is the tensile stress-strain curve of the PM6-b-PYHT film of the present invention. DETAILED DESCRIPTION

[0027] The present invention is further described below by means of specific examples, but these specific embodiments do not limit the protection scope of the present invention in any way.

[0028] Example 1

[0029] Taking PM6-b-PYIT as an example, the preparation method of a type of flexible single-component block polymer material described in this embodiment is based on the following steps.

[0030] 1.1 Synthesis of flexible polymer receptor fragments.

[0031] In a 25 ml reaction tube, Y5-2Br (60 mg, 0.0320 mmol), 2,5-bis(trimethyltinyl)thiophene (11.8 mg, 0.0288 mmol), 1,6-bis(5-(trimethyltinyl)thiophene)hexyl (1.8 mg, 0.0032 mmol), tridibenzylideneacetone dipalladium (0.59 mg, 0.00064 mmol), tri(o-methylphenyl)phosphine (0.78 g, 0.00256 mmol), and toluene (2 mL) were added in sequence. Under nitrogen protection, the mixture was stirred and refluxed in an oil bath at 110 °C for 5 h.

[0032] The synthetic route is as follows:

[0033]

[0034] 1.2 Synthesis of polymer donor fragments.

[0035] In a 10 ml reaction tube, BDT-2F (27.1 mg, 0.0288 mmol), BDD-2Br (22.1 mg, 0.0288 mmol), tetrakistriphenylphosphine palladium (3.7 g, 0.00317 mmol), and toluene (3 mL) were added in sequence. Under nitrogen protection, the mixture was stirred and refluxed in an oil bath at 110°C for 3 h.

[0036] The synthetic route is as follows:

[0037]

[0038] 1.3 Synthesis of flexible single components.

[0039] After the donor fragment and the receptor fragment were synthesized, the donor fragment was sucked out with a syringe and injected into the reaction tube of the polymer receptor, and the reaction was continued in a 110°C oil bath with stirring and reflux for 24 hours. After the reaction was completed, the polymer was injected into methanol for precipitation, filtered, and extracted with n-hexane, acetone, dichloromethane, and finally chloroform. The chloroform extraction product was collected and most of the solvent was evaporated under reduced pressure.

[0040] The molecular structure of the product is as follows:

[0041]

[0042] Example 2

[0043] Performance characterization of flexible single-component materials and preparation and testing of photovoltaic devices.

[0044] The UV-visible absorption spectrum of the flexible single-component material was measured by HP-8453 UV-visible spectrometer.

[0045] The organic solar cell device based on flexible single-component material includes: an indium tin oxide (ITO) conductive glass anode, an anode modification layer, a photoactive layer, a cathode modification layer, and a cathode. The anode modification layer is PEDOT / PSS (30nm); the cathode modification layer is PF3N (30nm), and the cathode is a deposited layer of Ag (100nm); the active layer material is PM6-b-PYIT or the flexible single-component block polymer material PM6-b-PYHT described in the present invention.

[0046] Example 3

[0047] Photophysical properties of PM6-b-PYHT and performance test of its single-component organic solar cell device.

[0048] The UV absorption spectrum of PM6-b-PYIT in solid mixed film is shown in Figure 1The absorption of PM6-b-PYHT is mainly distributed between 400nm-660nm and 700nm-830nm, with the donor absorption peak at 625nm and the acceptor absorption peak at 808nm. The UV absorption spectrum of PM6-b-PYHT in solid film is shown in Figure 2 The absorption of PM6-b-PYHT is mainly distributed between 400-660nm and 700nm-830nm, with the donor absorption peak at 626nm and the acceptor absorption peak at 806nm.

[0049] The cyclic voltammetry curve of PM6-b-PYIT in the solid film is shown in Figure 3 As shown. It presents reversible oxidation peak and reduction peak. According to the calculation formula E HOMO =-(E ox +4.40)eV, its HOMO energy level is -5.61eV; according to the calculation formula E LUMO =-(E red +4.40)eV, and their LUMO energy levels are -3.51eV respectively. From this calculation, the electrochemical band gap of PM6-b-PYIT is 2.10eV respectively.

[0050] The cyclic voltammetry curve of PM6-b-PYHT in solid film is shown in Figure 4 As shown. It presents reversible oxidation peak and reduction peak. According to the calculation formula E HOMO =-(E ox +4.40)eV, its HOMO energy level is -5.62eV; according to the calculation formula E LUMO =-(E red +4.40)eV, and their LUMO energy levels are -3.54eV. The electrochemical band gap of PM6-b-PYIT is calculated to be 2.08eV, which is similar to the performance of PM6-b-PYIT.

[0051] The JV curve of the photovoltaic device of PM6-b-PYIT is shown in Figure 5 The PM6-b-PYIT device exhibits good photovoltaic performance, with an open circuit voltage of 0.921 V and a short circuit current of 23.77 mA cm -2 , the fill factor is 66.20%, and the photoelectric conversion efficiency PCE is 14.51%. The JV curve of the photovoltaic device of PM6-b-PYHT is shown in Figure 6 The PM6-b-PYHT device exhibits good photovoltaic performance, with an open circuit voltage of 0.920 V and a short circuit current of 24.29 mA cm -2 , the filling factor is 63.82%, and the photoelectric conversion efficiency PCE is 14.26%.

[0052] The tensile stress-strain curve of PM6-b-PYIT film is shown in Figure 7 As shown in Figure 2, the PM6-b-PYIT film broke when the deformation reached 8.53% under tension, while the PM6-b-PYHT film broke when the deformation reached 14.56% (as shown in Figure 2). Figure 8 This indicates that replacing the rigid unit with a flexible unit can greatly improve the mechanical tensile properties of the single-component organic solar cell material.

[0053] Although the present invention has been described in conjunction with the preferred embodiments, the present invention is not limited to the above embodiments, and it should be understood that the appended claims summarize the scope of the present invention. Under the guidance of the inventive concept, those skilled in the art should be aware that certain changes made to the embodiments of the present invention will be covered by the spirit and scope of the claims of the present invention.

Claims

1. A class of flexible single-component block polymer materials characterized by It has the following molecular structure: Wherein, X is a H atom or a halogen atom, R1 and R2 are alkyl chains, and aa represents the length of the flexible chain.

2. A class of flexible single-component block polymer materials according to claim 1, characterized in that Including its derivatives.

3. The method for preparing a flexible single-component block polymer material according to claim 1, characterized in that Follow these steps: (1) Synthesis of BDT-based polymer donor fragments: The raw materials BDT-2F and BDD-2Br were polymerized in toluene solvent to obtain the polymer donor PM6 fragment; (2) Synthesis of polymer receptor material PYHT fragment: The raw materials 2,5-bis(trimethyltinyl)thiophene, 1,6-bis(5-(trimethyltinyl)thiophene)hexyl and Y5-2Br were polymerized in solvent toluene to obtain the polymer receptor PYHT fragment; (3) Synthesis of flexible single-component block polymer material PM6-b-PYHT: The obtained polymer donor PM6 fragment was transferred to the reaction tube of the polymer acceptor PYHT fragment by a syringe, and the polymerization was continued to preliminarily obtain the flexible single-component block polymer material PM6-b-PYHT; methanol was used for precipitation, and suction was filtered, and the solvents of n-hexane, acetone, dichloromethane and chloroform were used for extraction in sequence, and then the mixture was passed through a silica gel chromatography column, and finally concentrated, precipitated, and suction was filtered to obtain the flexible single-component block polymer material PM6-b-PYHT, whose molecular structure is as follows:

4. Use of the flexible single-component block polymer material according to claim 1 as a photoactive layer material in the preparation of a polymer single-component organic solar device.

5. The polymer single-component organic solar device according to claim 4, characterized in that It includes an indium tin oxide conductive glass anode, an anode modification layer, a photoactive layer, a cathode modification layer, and a cathode; The anode modification layer is PEDOT / PSS; the cathode modification layer is F3N; the cathode is a deposited layer of Ag; and the active layer material is the flexible single-component block polymer material.

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