Organic solar cell device quadripolymer donor and preparation and application thereof
Through the combination of tetra-copolymer design and non-fullerene receptors, the polymer structure of organic solar cells is optimized, and the problems of D-A copolymer and terpolymer are solved, and the problems of uneven monomer distribution are achieved are achieved with high efficiency Improved device performance.
Patent Information
- Application Number
- CN202411267384.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-11
- Publication Date
- 2024-12-13
AI Technical Summary
The efficiency of existing D-A copolymers and terpolymers in organic solar cells is sensitive to molecular weight changes. The random distribution of the third monomer affects the device efficiency and the micromorphology of the active layer, limiting the improvement of device performance.
Using a tetramer design, D1-A1-D2-A2 type tetramer donor is prepared by introducing new unit structures, combining non-fullerene acceptors, optimizing the structure and proportion of the polymer and improving device efficiency.
Through the quaternary copolymer design, the efficiency of the device is significantly improved, the molecular structure optimization reduces dihedral angle deflection, improves the morphology and charge separation efficiency of the active layer, and achieves a power conversion efficiency of 18.13%.
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Figure CN119119430A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of chemistry. Background Art
[0002] As the most important component in the device structure of organic solar cells, the active layer of organic solar cells is composed of donor and acceptor materials, among which the polymer donor material is usually DA copolymer and terpolymer. At present, PM6 and PBQ10 are the most commonly used DA copolymers, also known as alternating polymer donor materials. They have periodic molecular sequences and thus have high crystallinity and strong intermolecular stacking (①Zhang, M., Guo, X., Ma, W., et al, A Large-Bandgap Conjugated Polymer for Versatile Photovoltaic Applications with High Performance[J]. Advanced Materials, 27(31): 4655-60, 2015. ②Sun, C., Pan, F., Qiu, B., et al, D–A Copolymer Donor Based on Bithienyl Benzodithiophene D-Unit and Monoalkoxy Bifluoroquinoxaline A-Unit for High-Performance Polymer Solar Cells[J]. Chemistry of Materials, 32(7): 3254-3261, 2020.). Studies have shown that terpolymerization is a low-cost strategy for preparing high-performance new polymer donor materials (③Yang, T., Liao, C., Duan, Y., et al, Tradeoff between Intermolecular Interaction and Backbone Disorder by HighMolecular Dipole Block for Improving Blend Morphology of Polymer Solar Cells[J]. Advanced Functional Materials,, 32(51): 2208950, 2022. ④Lu, J.. Wu, J.. Huang, B., et al, Non-covalent Intramolecular Interactions Induced High-PerformanceTerpolymer Donors[J]. Advanced Functional Materials, 34(13): 2312545, 2023.).The diversity of the third monomer can expand the types of polymer donors, and by precisely controlling the content of the third monomer, donor polymers with better matching with non-fullerene acceptors can be obtained. However, although DA copolymers and terpolymers have shown great potential in OSCs, their limitations have gradually emerged (⑤Wu, J., Li, G., Fang, J., et al, Randomterpolymer based on thiophene-thiazolothiazole unit enabling efficient non-fullerene organic solar cells[J]. Nature Communications, 11, 4612, 2020.⑥Deng, X.;Huang, B., Fang, Y., et al, High-Performance Terpolymers with Well-DefinedStructures Facilitate PCE Over 19%for Polymer Solar Cells[J]. Advanced Functional Materials, 34(24): 2315476, 2024). First, the efficiency of devices based on PM6 and PBQ10 is very sensitive to changes in molecular weight, which limits their commercial application. Secondly, the random distribution of the third monomer may be detrimental to the continuous improvement of device efficiency and will affect the micromorphology of the active layer and the charge separation efficiency. Summary of the invention
[0003] The purpose of the present invention is to address the problems existing in the current design of active layer materials and to propose a high-performance quaternary polymer donor to broaden the types of molecular structure designs of organic solar cells and improve device performance.
[0004] Quaternary copolymerization can not only broaden the types of polymer donor materials, but also prepare donor polymers with higher matching degree with non-fullerene acceptors by precisely controlling the monomer ratio. In the present invention, a D1-A1-D2-A2 type quaternary polymer donor H4 was prepared by introducing two other units, which has higher device efficiency than PM6 and ternary copolymer H14. This result shows that quaternary copolymerization is of great significance for the design of donor materials, and it can obtain efficient polymer materials in a simple and convenient way.
[0005] The present invention is achieved through the following technical solutions.
[0006] The quaternary polymer donor for an organic solar cell device described in the present invention has the following basic unit structure:
[0007]
[0008] Wherein, D1 and D2 are donor groups, and D1 is (4,8-bis(5-(2-ethylhexyl)-4-fluorothienyl)benzo[1,2-B:4,5-B']dithienyl)bis(trimethyltinyl) (abbreviated as F-BDT):
[0009]
[0010] D2 is (5,5'-(2,6-bis(trimethylstannyl)benzo[1,2-B:4,5-B']dithiophene-4,8-diyl)bis(thiophene-5,2-diyl))bis(tripropylsilane) (abbreviated as Si-BDT):
[0011]
[0012] A1 is an acceptor group, 1,3-bis(5-bromothienyl)-5,7-bis(2-ethylhexyl)benzo[1,2-c:4,5-c']dithiophene-4,8-dione (2Br-BDD for short):
[0013]
[0014] A2 is an acceptor group, 5,8-bis(5-bromothiophene-2-yl)-6,7-difluoro-2-((2-hexyldecyl)oxy)quinoxaline (DFQ for short):
[0015]
[0016] The invention discloses a method for preparing a quaternary polymer donor for an organic solar cell device, comprising the following steps: adding donor groups D1 and D2 and acceptor groups A1 and A2 into a reaction bottle at a monomer ratio of 0.9:0.9:0.1:0.1 of the polymer, flushing the reaction container with argon for 15-20 minutes, adding a catalyst, flushing with argon again for 15-20 minutes, heating the reaction product to reflux at 115°C for 24 hours, stopping the reaction, pouring the reaction solution into methanol for sedimentation, filtering, and then extracting with n-hexane, acetone and chloroform respectively, and drying the final extraction solution with a rotary evaporator, sedimenting in methanol again, filtering, and obtaining a polymer donor H4.
[0017] The donor groups D1 and D2 are F-BDT and Si-BDT respectively, and the acceptor groups A1 and A2 are 2Br-BDD and DFQ respectively; the catalyst is Pd(PPh3)4.
[0018] The invention discloses an application of a quaternary polymer donor of an organic solar cell device in an organic solar cell device.
[0019] The obtained polymer donor and acceptor L8-BO (non-fullerene small molecule organic matter) were dissolved in 1,2,4-trimethylbenzene solution at a ratio of 1:1.2 to serve as the active layer of the organic solar device. ZnO was spin-coated on a clean ITO glass sheet, followed by the active layer, and finally molybdenum trioxide and silver were evaporated. The active layer concentration was 7.3 mg / mL, and the spin coating speed was 2000 r / min.
[0020] The present invention can obtain more types of tetrapolymers based on existing binary polymer materials through tetrapolymerization, which is a simple and effective way to prepare high-performance polymer donors.
[0021] The present invention, based on conventional binary DA copolymerization, performs Stille coupling polymerization on four donor (acceptor) groups to prepare a quaternary copolymer, thereby reducing the difficulty of molecular design and obtaining a quaternary copolymer with better performance. Experiments have shown that the molecular structure design of the quaternary polymer donor material optimizes its intermolecular stacking, reduces dihedral angle deflection, can significantly improve device performance, adjust molecular flatness, optimize active layer morphology, and the efficiency has reached 18.13%.
[0022] The beneficial effects of the present invention are as follows: by adjusting the donor and acceptor groups introduced into the polymer, the structure of the polymer donor is effectively regulated. oc 0.828V, J sc 27.79mAcm -2 , the fill factor (FF) is 78.78, and the power conversion efficiency is 18.13%, which has strong feasibility. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Figure 1 It is H4 in chloroform 1 H NMR spectrum.
[0024] Figure 2 It is H14 in chloroform 1 H NMR spectrum.
[0025] Figure 3 It is PM6 in chloroform 1 H NMR spectrum.
[0026] Figure 4 This is the test result of high temperature gel permeation chromatography (GPC) of H4 polymer donor, where Mn and PDI are 35.82 kDa and 2.51, respectively.
[0027] Figure 5 This is the test result of high temperature gel permeation chromatography (GPC) of H14 polymer donor, where Mn and PDI are 34.64 kDa and 3.12, respectively.
[0028] Figure 6 It is the test result of high temperature gel permeation chromatography (GPC) of PM6 polymer donor, where Mn and PDI are 35.07 kDa and 2.71 respectively.
[0029] Figure 7 It is the electronic structure diagram of H4 calculated by density functional theory (DFT), in which the dihedral angles θ1, θ2 and θ3 are -5.63°, -10.4° and 8.65°, respectively.
[0030] Figure 8 This is the electronic structure diagram of H14 calculated by density functional theory (DFT), where the dihedral angles θ1, θ2, and θ3 are 7.99°, -9.53°, and 11.02°, respectively.
[0031] Fig. 9 This is the electronic structure diagram of PM6 calculated by density functional theory (DFT), in which the dihedral angle deviations θ1, θ2 and θ3 are 1.4°, -2.39° and -8.95°, respectively.
[0032] Fig.10 This is a diagram of the structure of an organic solar cell device.
[0033] Fig.11 It is a device efficiency diagram of three devices H4:L8-BO, H14:L8-BO, and PM6:L8-BO prepared by the present invention using H4, H14, and PM6 as donors. DETAILED DESCRIPTION
[0034] The present invention will be further described by the following examples and comparative examples.
[0035] In order to systematically study the effect of the number of polymer monomers on device performance, we prepared binary, ternary and quaternary polymer donor materials, named PM6, H14 and H4 respectively.
[0036] Example 1: Synthesis of tetrapolymer H4 and preparation of solar cells.
[0037] 0.0200 g (0.0213 mmol) of F-BDT, 0.0163 g (0.0213 mmol) of 2Br-BDD, 0.0021 g (0.0022 mmol) of Si-BDT, 0.0016 g (0.0022 mmol) of DFQ and anhydrous toluene (7 mL) were added to a 50 mL two-necked round-bottom flask. The reaction vessel was flushed with argon for 20 min, and 0.0015 g (0.0013 mmol) of Pd(PPh3)4 was added. After flushing with argon for another 20 min, the reaction product was heated to reflux at 115°C for 24 h to obtain prepolymer I. The reactant was cooled to room temperature, poured into methanol (50 mL), and then purified by extraction with n-hexane, acetone and chlorobenzene Soxhlet. The resulting binary copolymer H4 (yield 70%) was recovered as a solid from chloroform by methanol precipitation and dried under vacuum for 24 h. Elemental analysis calculated for H4: C, 67.156; H, 6.659; F, 3.044; ; S, 20.026; O, 2.434; N, 0.227; Si, 0.455.
[0038] The obtained polymer donor and acceptor L8-BO (non-fullerene small molecule organic matter) were dissolved in 1,2,4-trimethylbenzene solution at a ratio of 1:1.2 to serve as the active layer of the organic solar device. ZnO was spin-coated on a clean ITO glass sheet, followed by the active layer, and finally molybdenum trioxide and silver were evaporated. The active layer concentration was 30 mg / mL, and the spin coating speed was 1800 r / min. The structure of the solar cell is shown in the figure. Fig.10 shown.
[0039]
[0040] Comparative Example 1: Synthesis of binary copolymer PM6 and preparation of solar cells.
[0041] 0.0200 g (0.0213 mmol) of F-BDT, 0.0163 g (0.0213 mmol) of 2Br-BDD and anhydrous toluene (7 mL) were added to a 50 mL double-necked round-bottom flask. The reaction vessel was flushed with argon for 20 min, and 0.0015 g (0.0013 mmol) of Pd(PPh3)4 was added. After flushing with argon for another 20 min, the reaction product was heated to reflux at 115°C for 24 h to obtain a crude product. The reactants were cooled to room temperature, poured into methanol (50 mL), and then purified by extraction with n-hexane, acetone and chlorobenzene Soxhlet. The resulting binary copolymer PM6 (yield 70%) was recovered as a solid from chloroform by methanol precipitation and dried under vacuum for 24 h. Elemental analysis calculated for PM6: C, 67.27; H, 6.61; F, 3.04; S, 20.52; O, 2.56.
[0042] The obtained polymer donor and acceptor L8-BO (non-fullerene small molecule organic matter) were dissolved in 1,2,4-trimethylbenzene solution at a ratio of 1:1.2 to serve as the active layer of the organic solar device. ZnO was spin-coated on a clean ITO glass sheet, followed by the active layer, and finally molybdenum trioxide and silver were evaporated. The active layer concentration was 7.3 mg / mL, and the spin coating speed was 2000 r / min. The structure of the solar cell is shown in the figure. Fig.10 shown.
[0043]
[0044] Comparative Example 2: Synthesis of terpolymer H14 and preparation of solar cells.
[0045] 0.0200 g (0.0213 mmol) of F-BDT, 0.0163 g (0.0213 mmol) of 2Br-BDD, 0.0016 g (0.0022 mmol) of DFQ and anhydrous toluene (7 mL) were added to a 50 mL double-necked round-bottom flask. The reaction vessel was flushed with argon for 20 min, and 0.0015 g (0.0013 mmol) of Pd(PPh3)4 was added. After flushing with argon for another 20 min, the reaction product was heated to reflux at 115°C for 24 h to obtain a crude product. The reactant was cooled to room temperature, poured into methanol (50 mL), and then purified by extraction with n-hexane, acetone and chlorobenzene Soxhlet. The resulting binary copolymer H14 (yield 82%) was recovered as a solid from chloroform by methanol precipitation and dried under vacuum for 24 h. Elemental analysis calculated for H14: C, 66.94; H, 6.614; F, 6.095; N, 2.36; S, 16.192; O, 1.345; Si, 0.455.
[0046] The obtained polymer donor and acceptor L8-BO (non-fullerene small molecule organic matter) were dissolved in 1,2,4-trimethylbenzene solution at a ratio of 1:1.2 to serve as the active layer of the organic solar device. ZnO was spin-coated on a clean ITO glass sheet, followed by the active layer, and finally molybdenum trioxide and silver were evaporated. The active layer concentration was 7.3 mg / mL, and the spin coating speed was 2000 r / min. The structure of the solar cell is shown in the figure. Fig.10 shown.
[0047]
[0048] The solar cells prepared in the above examples were characterized by instrument testing, and the results are as follows:
[0049] Depend on Figure 4-6 It can be seen that the three polymers have similar molecular weights and are comparable.
[0050] Depend on Figure 7 It can be seen that the tetrapolymer H4 exhibits a smaller dihedral angle and a deeper HOMO energy level than Figure 8 H14 and Fig. 9 PM6 tends to be more densely packed, which helps to improve the crystallinity.
[0051] Depend on Fig.11 It can be seen that the organic solar cells based on the tetrapolymer H4 show better device performance than the devices prepared based on H14 and PM6.
Claims
1. A quaternary polymer donor for an organic solar cell device, characterized in that It has the following basic unit structure: Wherein, D1 and D2 are donor groups, and D1 is (4,8-bis(5-(2-ethylhexyl)-4-fluorothienyl)benzo[1,2-B:4,5-B']dithienyl)bis(trimethyltinyl): D2 is (5,5'-(2,6-bis(trimethylstannyl)benzo[1,2-B:4,5-B']dithiophene-4,8-diyl)bis(thiophene-5,2-diyl))bis(tripropylsilane): A1 is an acceptor group, 1,3-bis(5-bromothienyl)-5,7-bis(2-ethylhexyl)benzo[1,2-c:4,5-c']dithiophene-4,8-dione: A2 is an acceptor group, 5,8-bis(5-bromothiophen-2-yl)-6,7-difluoro-2-((2-hexyldecyl)oxy)quinoxaline:
2. The method for preparing a quaternary polymer donor for an organic solar cell device according to claim 1, characterized in that The following steps are involved: The donor groups D1 and D2 and the acceptor groups A1 and A2 are added to the reaction bottle at a monomer ratio of 0.9:0.9:0.1:0.1 of the polymer, and the reaction container is flushed with argon for 15-20 minutes. After adding the catalyst, it is flushed with argon again for 15-20 minutes, and the reaction product is heated to reflux at 115°C for 24 hours to stop the reaction. The reaction solution is poured into methanol for precipitation, filtered, and then extracted with n-hexane, acetone, and chloroform respectively. The final extraction solution is dried by rotary evaporator, precipitated in methanol again, and filtered to obtain polymer donor H4; Among them, D1 is (4,8-bis(5-(2-ethylhexyl)-4-fluorothienyl)benzo[1,2-B:4,5-B']dithienyl)bis(trimethyltinyl); D2 is (5,5'-(2,6-bis(trimethyltinyl)benzo[1,2-B:4,5-B']dithiophene-4,8-diyl)bis(thiophene-5,2-diyl))bis(tripropylsilane); A1 is 1,3-bis(5-bromothienyl)-5,7-bis(2-ethylhexyl)benzo[1,2-c:4,5-c']dithiophene-4,8-dione: A2 is 5,8-bis(5-bromothien-2-yl)-6,7-difluoro-2-((2-hexyldecyl)oxy)quinoxaline: the catalyst is Pd(PPh3)4.
3. Application of the quaternary polymer donor of an organic solar cell device according to claim 1 in an organic solar device: dissolving the obtained polymer donor and the acceptor L8-BO in a 1:1.2 ratio in 1,2,4-trimethylbenzene solution as the active layer of the organic solar device; spin coating ZnO on a clean ITO glass sheet and then spin coating the active layer, and finally evaporating molybdenum trioxide and silver; the active layer concentration is 7.3 mg / mL, and the spin coating speed is 2000 r / min.