Use of a class of imide-based large dipole moment volatile solid additives in bulk heterojunction organic solar cells
By using imide-based volatile solid additives with large dipole moments in organic solar cells, the problems of existing additives being difficult to remove and having limited variety have been solved, thereby improving photoelectric performance and stability and reducing costs.
Patent Information
- Application Number
- CN202510194241.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-21
- Publication Date
- 2026-01-16
- Estimated Expiration
- 2045-02-21
AI Technical Summary
Existing additives with large dipole moments are difficult to remove from organic solar cells, affecting device stability. At the same time, the types of existing additives are limited, making it difficult to effectively control the morphology of the active layer.
A large dipole moment volatile solid additive based on imide was developed to improve morphological stability and photoelectric performance by regulating intermolecular interactions and used as the photoactive layer of bulk heterojunction organic solar cells at a ratio of 3-30% of the donor mass.
It achieves better molecular stacking regulation, enhances the morphological stability of the active layer, improves photoelectric performance, reduces costs, and the additives can be completely removed by annealing to form a uniform acceptor domain, which improves exciton dissociation and charge transport.
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Figure CN120097892B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the field of organic solar cells, in particular, the present application relates to a class of imide-based large dipole moment volatile solid additives in bulk heterojunction organic solar cells. BACKGROUND
[0002] Organic solar cells have been widely studied due to their advantages such as lightness, flexibility, and solution processing. In bulk heterojunction organic solar cells, the active layer formed by blending donor and acceptor materials is an important part of photoelectric conversion, and its photoelectric conversion efficiency is highly dependent on the morphology of the active layer. Solid additives are an important morphology adjustment strategy (Chinese patents, publication numbers: CN110518120A, CN119277880A, CN118890906A).
[0003] Currently, most solid additives are based on benzene or thiophene aromatic ring derivatives, and the dipole moment is usually small, limiting the interaction with donor-acceptor molecules. Large dipole moment additive molecules have strong intermolecular interactions, which can more effectively act on donor-acceptor molecules, optimize their packing behavior, improve the morphology of organic solar cells, and enhance the photoelectric performance. However, large dipole moment additives often have strong intermolecular interactions, which are generally difficult to remove after the preparation of solar cells, thereby negatively affecting the stability of organic solar cells (OSCs). Therefore, it is extremely challenging to develop solid additives with large dipole moments and good volatility. SUMMARY
[0004] In view of the current research status of solid additives for organic solar cells, the purpose of the present application is to develop a class of solid additives with large dipole moments and good removability to improve the performance of organic solar cell devices. The method of adjusting the dihedral angle of imide to control intermolecular interactions is used to realize the volatility of large dipole moment additives.
[0005] The technical solution adopted by the present application is: the application of a class of imide-based large dipole moment volatile solid additives, the solid additive has the following structural general formula:
[0006]
[0007] Wherein, Ar1 is ; R1, R2, R3, R4, R5 are each independently F, Cl, Br, I or H.
[0008] Ar2 is ; R9, R10, R11, R12 are each independently F, Cl, Br, I or H.
[0009] and R1, R2, R3, R4, R5, R9, R10, R11, R12 are not simultaneously H.
[0010] The solid additive is used as a solid additive of a bulk heterojunction organic solar cell.
[0011] Further, in the above simultaneous structure, R1, R2, R3, R4, R5 are not simultaneously H, and R9, R10, R11, R12 can be simultaneously H.
[0012] Further, the solid additive is used in a photoactive layer of a bulk heterojunction organic solar cell.
[0013] Further, the solid additive is used in a photoactive layer of a PM6:BTP-eC9 bulk heterojunction organic solar cell.
[0014] Further, the photoactive layer of the PM6:BTP-eC9 bulk heterojunction organic solar cell comprises a donor, an acceptor and the solid additive, and the mass of the solid additive is 3-30% of the mass of the donor.
[0015] The preparation method of the imide-based large-dipole-moment volatile solid additive,
[0016]
[0017] The compound (I) and the compound (II) are reacted in a solution to obtain the above solid additive.
[0018] Specifically, the compound I and the compound II are dosed at a molar ratio of 1:1-20, the reaction temperature is 150-160 DEG C, the reaction time is 2-8 h, and the solvent is N,N-dimethylformamide.
[0019] The beneficial effects of the present application are:
[0020] 1. The additive with a large dipole moment can better interact with the donor and the acceptor, and has a better regulating effect on the molecular packing and the active layer morphology.
[0021] 2. The large-dipole-moment additive has good volatility and can be completely removed by annealing, which is conducive to enhancing the stability of the active layer morphology.
[0022] 3. At present, most solid additives are based on benzene ring and thiophene derivatives, and the development of imide-type additives is conducive to expanding the types of additives.
[0023] 4. The large-dipole-moment additive can induce the acceptor to nucleate first and then grow, which is conducive to forming acceptor domains with uniform size and improving exciton dissociation and charge transport.
[0024] 5. Thanks to the strong intermolecular interaction of the large dipole moment additive, the additive in the application is used in the proportion of only 3%-30% of the donor mass in the bulk heterojunction organic solar cell, which is far lower than 150% of the commonly used additive 1,4-diiodobenzene in the market, and is conducive to reducing the cost. BRIEF DESCRIPTION OF DRAWINGS
[0025] Figure 1 The Fourier infrared spectra of the additive pClPA, the mixture PM6:BTP-eC9 and PM6:BTP-eC9:pClPA before and after annealing.
[0026] Figure 2 The in-situ UV-visible absorption spectra of the active layer solution (PM6:BTP-eC9) treated with or without the additive pClPA, and the change of the maximum absorption peak position of the donor with time.
[0027] Figure 3 The current density-voltage curve of the PM6:BTP-eC9 bulk heterojunction organic solar cell device treated without additive, treated with the commonly used additive 1,4-diiodobenzene in the market and treated with the additive pClPA described in Example 1.
[0028] Figure 4 The current density-voltage curve of the PM6:BTP-eC9 bulk heterojunction organic solar cell device treated without additive, and treated with the additive pFPA, pBrPA, pIPA, 3FPA, 3FPA-1, 5FPA described in the application.
[0029] Figure 5 The dihedral angle of the additive oClPA, mClPA, pClPA described in the application. DETAILED DESCRIPTION
[0030] The experimental methods used in the following examples are all conventional methods unless otherwise specified.
[0031] The materials, reagents and the like used in the following examples can be obtained from commercial channels unless otherwise specified.
[0032] The technical solutions of the application will be further specifically described through specific examples. It should be understood that the implementation of the application is not limited to the following examples, and any form of variation or change of the application will fall within the scope of protection of the application. In the application, unless specified, all parts, percentages are mass units, and the equipment and raw materials used can be purchased from the market or are commonly used in the art.
[0033] The following is explained in the examples:
[0034] Example 1
[0035]
[0036] In a 25 mL reaction flask, 500 mg of phthalic anhydride, 430 mg of 4-chloroaniline were added, using 7 mL of N,N-dimethylformamide as solvent. The reaction was carried out at 150 °C for 2.5 h under argon protection. After the reaction was completed, the reaction solution was cooled to room temperature, and then poured into ice water. The solid was collected by filtration. The product was purified by column separation and recrystallized with methanol and chloroform to obtain white crystals of pClPA (796 mg, 91.60 %). The product was identified by mass spectrometry. HRMS (MALDI-TOF) Calcd for C 14 H8ClNO2 Exact Mass: 257.0244, found: 257.0187 (M + ).
[0037] Example 2
[0038]
[0039] In a 25 mL reaction flask, 500 mg of phthalic anhydride, 497 mg of 3,4,5-trifluoroaniline were added, using 7 mL of N,N-dimethylformamide as solvent. The reaction was carried out at 150 °C for 3.5 h under argon protection. After the reaction was completed, the reaction solution was cooled to room temperature, and then poured into ice water. The solid was collected by filtration. The product was purified by column separation and recrystallized with methanol and chloroform to obtain white crystals of 3FPA (872 mg, 93.20 %). The product was identified by mass spectrometry. HRMS (MALDI-TOF) Calcd for C 14 H6F3NO2 Exact Mass: 277.0351, found: 277.0255 (M + ).
[0040] Example 3
[0041]
[0042] In a 25 mL reaction flask, 500 mg of phthalic anhydride, 497 mg of 3,4,5-trifluoroaniline were added, using 7 mL of N,N-dimethylformamide as solvent. The reaction was carried out at 150 °C for 3.5 h under argon protection. After the reaction was completed, the reaction solution was cooled to room temperature, and then poured into ice water. The solid was collected by filtration. The product was purified by column separation and recrystallized with methanol and chloroform to obtain white crystals of 3FPA (872 mg, 93.20 %). The product was identified by mass spectrometry. HRMS (MALDI-TOF) Calcd for C 14H7Cl2NO2Exact Mass: 290.9854, found: 290.9754 (M+).
[0043] The following imide additives were synthesized according to the method of the above examples, and the structure of the product was identified by mass spectrometry.
[0044]
[0045] Example 4
[0046] The solid additive pClPA synthesized in Example 1 and the commonly used additive 1,4-diiodobenzene on the market were applied to the PM6:BTP-eC9 bulk heterojunction organic solar cell. The specific steps are as follows: first, the conductive ITO substrate was cleaned. It was sequentially ultrasonically cleaned in deionized water, acetone and isopropanol for 30 min, and then the dried ITO substrate was placed in a plasma cleaning instrument for cleaning for 3 min to completely remove the surface organic matter. Then, PEDOT:PSS was spin-coated on the treated ITO substrate. The PEDOT:PSS was uniformly spin-coated on the surface of the ITO substrate at a speed of 4000 rpm, and after spin-coating, it was annealed at 150°C for 18 min, and then the ITO substrate was transferred to the glove box. The donor PM6 and the acceptor BTP-eC9 were dissolved in chloroform at a mass ratio of 1:1.2 to prepare a solution with a total concentration of 15.4 mg / mL. Add the additive pClPA with a mass of 15% of the donor to the solution to prepare the active layer solution treated with the additive pClPA; add the additive DIB with a mass of 150% of the donor to the solution to prepare the active layer solution treated with the additive DIB. The prepared active layer solution needs to be stirred at 40°C for 3 h in advance for standby. The active layer solution was spin-coated on the surface of PEDOT:PSS at a speed of 4000 rpm, and then annealed at 100°C for 10 min. Subsequently, 0.5 mg / mL of PNDIT-F3N methanol solution was spin-coated on the surface of the active layer at a speed of 3000 rpm. Finally, under the pressure of about 10⁻ 4 Pa, silver electrode was evaporated on the surface of PNDIT-F3N, and the thickness of the silver electrode was about 80 nm, to obtain an organic solar cell device.
[0047] Among them, PM6, BTP-eC9 and PNDIT-F3N were purchased from Solarmer; 1,4-diiodobenzene was purchased from TCI; chloroform and methanol were purchased from Bailingwei Technology; PEDOT:PSS was purchased from Heraeus.
[0048] In the N2-filled glove box, AAA-grade solar simulator AM 1.5 G (100 mW / cm 2) The open-circuit voltage, short-circuit current, fill factor and energy conversion efficiency of the prepared photovoltaic devices were tested, as shown in Table 1 and Figure 3 The additive pClPA can effectively improve the short-circuit current (J SC ) and fill factor (FF), and the energy conversion efficiency is increased from 16.13% to 18.58%, which is higher than 17.74% of 1,4-diiodobenzene. This is due to the larger dipole moment of the additive pClPA, which has stronger intermolecular interaction with the donor and acceptor than 1,4-diiodobenzene, which is more conducive to improving the morphology of the active layer.
[0049] Table 1 Photovoltaic device test data
[0050]
[0051] Example 5
[0052] The additive pFPA, pBrPA, pIPA, 3FPA, 3FPA-1, 5FPA treated PM6:BTP-eC9 bulk heterojunction organic solar cell devices were prepared by referring to the method of Example 4 above, and the open-circuit voltage, short-circuit current, fill factor and energy conversion efficiency of the prepared photovoltaic devices were tested, as shown in Table 2 and Figure 4 .
[0053] Table 2 Photovoltaic device test data
[0054]
[0055] Benefiting from the strong intermolecular interaction of the large dipole moment additive, the use ratio of the additive described in the present application in the bulk heterojunction organic solar cell is only 3%-30% of the mass of the donor, which is much lower than 150% of the commonly used additive 1,4-diiodobenzene in the market, which is conducive to reducing the cost.
[0056] Example 6
[0057] The Fourier infrared spectrometer was used to verify the volatility of the additive pClPA in Example 1. As shown in Figure 1 , the characteristic peaks of the additive pClPA at 1713 cm -1 , 824 cm -1 and 716 cm -1 almost completely disappeared after annealing at 100°C for 10 min, which indicates that the additive pClPA can be removed by annealing. As shown in Figure 5 , the dihedral angles of the additives oClPA, mClPA and pClPA described in the present application are 37.8°, 37.9° and 68.4° respectively, which helps to reduce the planarity of the additive molecules, control the intermolecular interaction and enhance the volatility of the additive.
[0058] Example 7
[0059] The effect of the additive pClPA in Example 1 on the film-forming kinetics of the donor and acceptor was investigated using in-situ UV-Vis absorption spectroscopy. Figure 2 As shown, the position of the maximum absorption peak of the receptor changes over time. Compared with the donor, the additive pClPA has a more significant effect on the receptor. With the evaporation of the solvent, the entire film formation process can be simply divided into three stages: the first stage, the solution state, where the position of the maximum absorption peak remains almost unchanged; the second stage, the crystallization and growth stage, where the maximum absorption peak rapidly red-shifts; and the third stage, the thin film state, where the position of the maximum absorption peak tends to stabilize again. The crystallization and growth stage of the receptor lasts for 12 s and maintains a uniform red-shift, indicating that receptor nucleation and crystal growth occur simultaneously, which may generate receptor domains of non-uniform size, restricting charge transport. The crystallization and growth stage of the receptor treated with additive pClPA is extended to 22 s, which is conducive to the formation of ordered intermolecular stacking. In addition, the crystallization and growth stage of the receptor is divided into three parts, indicating that additive pClPA can induce receptor nucleation first and then growth, which is beneficial to the generation of receptor domains of uniform size.
[0060] Finally, it should be emphasized that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. Use of imide-type large dipole moment volatile solid additives characterized in that, The solid additive has the following structure: ； The solid additive is used in a photoactive layer of a bulk heterojunction organic solar cell.
2. Use of a class of imide-based, large-dipole-moment, volatile solid additives according to claim 1, characterized in that: The solid additive is used in a photoactive layer of a PM6:BTP-eC9 bulk heterojunction organic solar cell.
3. Use of a class of imide-based, large dipole moment, volatile solid additives according to claim 2, characterized in that: The photoactive layer of the PM6:BTP-eC9 bulk heterojunction organic solar cell comprises a donor, an acceptor and a solid additive, and the mass of the solid additive is 3-30% of the mass of the donor.