A method for regulating the crystallization orientation of a pyrrolopyrrole dione donor-acceptor conjugated polymer
Thermal and solvent annealing methods simplify the control of crystalline orientation in pyrrole-2,5-dione-based polymers, enhancing their applicability in electronic devices by alternating between side-standing and lying-down configurations.
Patent Information
- Application Number
- CN202210593344.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-05-27
- Publication Date
- 2025-07-15
- Estimated Expiration
- 2042-05-27
AI Technical Summary
The prior art is difficult to effectively regulate the crystallization orientation of pyrrolopyrrole dione donor-acceptor conjugated polymers, resulting in poor carrier mobility performance, especially in different types of organic optoelectronic devices.
By alternating thermal annealing and solvent annealing, the molecular chains of pyrrolopyrrole dione donor-acceptor conjugated polymers are regulated to achieve a reversible transformation of flat and sideways on the substrate, including high-temperature thermal annealing and long-term solvent annealing in a confined space of chloroform solvent.
The reversible transformation of the crystal orientation of conjugated polymers has been achieved, and the carrier mobility performance has been improved. It is suitable for a variety of organic photoelectric devices, such as planar structure field effect transistors, vertical structure field effect transistors and organic solar cells.
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Figure CN115058023B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of optoelectronic polymer materials, and particularly to a method for regulating the crystal orientation of donor-acceptor conjugated polymers based on pyrrolopyrrole dione. Background Art
[0002] Conjugated polymers are a popular topic in the scientific research field. After more than a decade of development, important progress has been made in the molecular structure design and processing technology of conjugated polymers, and the performance of the field-effect transistors constructed by them has been significantly improved. The carrier mobility performance of conjugated polymers not only depends on the molecular structure of the conjugated units, but also is related to the crystal orientation of the polymer thin film. High-performance conjugated polymer materials are mainly based on electron donor-acceptor (D-A) molecular systems. Thiophene is a relatively common donor unit, and pyrrolopyrrole dione (DPP) is a relatively common electron acceptor unit. The copolymerization of pyrrolopyrrole dione and thiophene to form donor-acceptor conjugated polymers is widely used in the field of organic optoelectronic devices.
[0003] In recent years, the crystal form regulation of donor-acceptor conjugated polymers has attracted the attention of many researchers to meet the requirements of different device types. When the conjugated polymer is arranged in a standing-on-edge orientation on the substrate, that is, the conjugated backbone is parallel to the substrate, it is helpful for the carrier transport of planar-structured field-effect transistors (Adv. Mater. 2016, 28, 9430-9438). If the polymer lies flat on the substrate, that is, the polymer plane is parallel to the substrate, it will lead to a decrease in the carrier mobility of the field-effect transistor, but it may increase the carrier mobility in vertical-structured field-effect transistors and improve the efficiency in organic solar cell devices (Chem. Mater. 2021, 33, 4541-4550). Therefore, the standing-on-edge arrangement of conjugated polymers is an ideal arrangement form in planar-structured OFETs. The current research progress has reported many methods to regulate the arrangement of conjugated polymers on the substrate, including methods such as changing the molecular structure, molecular weight, and regularity. However, there are few studies on regulating the standing-on-edge and lying-flat crystal orientations of polymers at present, and the regulation methods are all based on complex molecular structure design and surface substrate modification, and the process is relatively complex. Summary of the Invention
[0004] The purpose of the present invention is to overcome the defects of the above-mentioned existing technologies and provide a method for regulating the crystal orientation of donor-acceptor conjugated polymers based on pyrrolopyrrole dione, which is of great significance for realizing the wide application of conjugated polymers in various structural devices. Through the regulation of the polymer molecular chain from lying flat to standing on edge, it can be applied in various types of devices, including planar-structured field-effect transistors and vertical-structured field-effect transistors.
[0005] The object of the present invention can be achieved by the following technical solutions:
[0006] The object of the present invention is to provide a method for regulating the crystallization orientation of a pyrrolopyrrole dione donor-acceptor conjugated polymer. The regulation method is as follows: through thermal annealing or solvent annealing, the molecular chains of the pyrrolopyrrole dione donor-acceptor conjugated polymer (DPP3T) form a transformation between lying flat and standing upright on the substrate.
[0007] Furthermore, the molecular structural formula of the pyrrolopyrrole dione donor-acceptor conjugated polymer is as follows:
[0008]
[0009] Wherein R is an alkyl side chain with a branched structure.
[0010] Furthermore, the number-average molecular weight of the pyrrolopyrrole dione donor-acceptor conjugated polymer is 18,000 - 40,000 kg / mol.
[0011] Furthermore, when through solvent annealing, the alkyl side chain density of the pyrrolopyrrole dione donor-acceptor conjugated polymer has a positive correlation with the number of molecules inducing the crystallization orientation transformation.
[0012] Furthermore, it is more suitable that the alkyl side chain density refers to the side chain density of the following structural formula.
[0013]
[0014] Furthermore, the crystallization orientation transformation of the DPP3T conjugated polymer has annealing temperature and time dependence, and the concentration of the DPP3T conjugated polymer solution is controlled by changing the ratio of DPP3T to the solvent.
[0015] Furthermore, the process of regulating the crystallization orientation includes:
[0016] Forming a standing upright orientation of the pyrrolopyrrole dione donor-acceptor conjugated polymer through thermal annealing;
[0017] Achieving the transformation from standing upright to lying flat by placing the pyrrolopyrrole dione donor-acceptor conjugated polymer in a closed atmosphere of chloroform solvent;
[0018] Repeatedly achieving the reversible transformation process between standing upright and lying flat in this way.
[0019] Furthermore, the process of regulating the reversible transformation includes:
[0020] Dissolving the pyrrolopyrrole dione donor-acceptor conjugated polymer in a good solvent, and then naturally cooling and dropping it on a square silicon wafer to form a lying flat crystallization orientation;
[0021] After high-temperature annealing, a standing crystal orientation is formed, and then it is placed in a closed space with chloroform solvent for solvent annealing to form a lying crystal orientation, thereby forming a reversible transformation between the lying and standing crystal orientations of the conjugated polymer.
[0022] Furthermore, the regulation of the reversible transformation process includes:
[0023] (a) Take a pyrrolopyrrole dione-based donor-acceptor conjugated polymer and add it to chloroform solvent to obtain a DPP3T polymer solution;
[0024] (b) Heat and stir the DPP3T polymer solution until it reaches a completely dissolved state, and then drop it onto a silicon wafer and let it dry naturally to form a uniform thin film, thereby forming a lying crystal orientation;
[0025] (c) Use a pipette to transfer and drop the DPP3T polymer solution cooled to room temperature onto a square silicon wafer, and perform high-temperature thermal annealing treatment in an argon atmosphere to form a standing crystal orientation. After the annealing is completed, place it in a closed space with a chloroform vapor atmosphere for solvent annealing treatment to form a lying crystal orientation;
[0026] (d) Place the silicon wafer after solvent annealing on a hot stage and heat it to remove the residual solvent on the surface, thereby forming a reversible transformation between the lying and standing crystal orientations of the conjugated polymer.
[0027] Furthermore, in step (a), the concentration of the DPP3T solution is controlled to 5 - 10 mg / mL by changing the ratio of DPP3T to the solvent;
[0028] In step (b), the DPP3T polymer solution is heated and stirred at 80 °C for at least 6 h until it reaches a completely dissolved state.
[0029] Furthermore, in step (c), the DPP3T polymer solution cooled to room temperature is transferred and dropped onto a square silicon wafer, and high-temperature thermal annealing treatment is performed in an argon atmosphere for 3 - 6 h, and the temperature range is 230 - 270 °C. After the annealing is completed, place it in a closed space with a chloroform vapor atmosphere for solvent annealing treatment, and the solvent annealing time is 72 h - 96 h;
[0030] In step (d), the silicon wafer after solvent annealing is placed on an 80 °C hot stage for heating.
[0031] Compared with the prior art, the present invention has the following technical advantages:
[0032] 1. The conjugated polymer DPP3T used in this technical solution has a relatively large alkyl side chain density, and the solvent is generally a good solvent such as chloroform. This method has the advantage of simple operation.
[0033] 2. This technical solution designs a set of rigorous crystallization orientation transformation logics and corresponding operation means. Among them, the transformation of the crystal form of the DPP3T copolymer from lying flat to standing upright requires high-temperature thermal annealing, while the reversible transformation from standing upright to lying flat is achieved through long-term solvent annealing in a closed space in chloroform solvent. And this solution clearly defines the time dependence. When the solvent annealing time is short, the crystallization orientation transformation from standing upright to lying flat cannot occur.
[0034] 3. In this technical solution, through the alternating operation of thermal annealing and solvent annealing, the reversible transformation of the crystal form of the DPP3T copolymer can be realized on the substrate, and it can be cycled multiple times.
[0035] 4. The method of regulating the crystallization orientation transformation of the conjugated polymer DPP3T through the alternating operation of thermal annealing and solvent annealing in this technical solution is simple to operate, and it has great significance for the wide application of conjugated polymers in various structural devices. Through the regulation of the polymer molecular chain from lying flat to standing upright, it can be applied in various types of devices, including planar structure field-effect transistors, vertical structure field-effect transistors, organic solar cells, diodes, etc. Brief Description of the Drawings
[0036] Figure 1 It is a schematic diagram of solvent annealing of the DPP3T conjugated polymer thin film, in which the DPP3T is subjected to solvent annealing in an atmosphere with chloroform vapor;
[0037] Figure 2 It is a grazing incidence X-ray schematic diagram (GIXRD) of different crystallization orientations of the DPP3T conjugated polymer thin film;
[0038] Figure 3 It is a schematic diagram of different crystal form arrangements of the DPP3T conjugated polymer thin film. Detailed Embodiments
[0039] In the present invention, the donor-acceptor conjugated polymer (DPP3T) obtained by copolymerizing a single thiophene unit with an acceptor DPP unit can achieve the reversible transformation of the lying flat and standing upright crystallization orientations of the conjugated polymer through thermal annealing in an argon atmosphere and solvent annealing in a closed space. The crystal forms with different crystal structures can be applied to various types of devices, including planar structure field-effect transistors, vertical structure field-effect transistors, organic solar cells, diodes, etc. The method provided by the present invention for regulating the crystal form of the donor-acceptor conjugated polymer is simple and easy to operate, avoiding complex molecular structure design, and has application prospects.
[0040] The present invention will be described in detail below with reference to the drawings and specific embodiments. In this technical solution, features such as preparation means, materials, structures, or composition ratios that are not clearly described are regarded as common technical features disclosed in the prior art.
[0041] Example 1
[0042] 10 mg of DPP3T conjugated polymer was added to 0.5 mL of chloroform solvent to prepare a polymer solution with a concentration of 10 mg / mL. It was stirred at 80 °C for at least 6 h until it reached a completely dissolved state. The DPP3T conjugated polymer solution showed a dark blue color. The completely dissolved DPP3T solution was naturally cooled to room temperature. The DPP3T solution cooled to room temperature was transferred onto a square silicon wafer using a pipette and allowed to evaporate naturally to form a uniform thin film. Schematic diagrams of different crystal form arrangements are as shown in the appendix Figure 3 , which are the lying - down and standing - side - by - side arrangements respectively. The DPP3T polymer showed a lying - down crystal orientation. Then it was placed in a glove box with an argon atmosphere and subjected to thermal annealing at 230 °C for 3 h, showing a standing - side - by - side crystal orientation. Then the silicon wafer was moved to a closed space with chloroform solvent at the bottom of the container for solvent annealing. The annealing time was 72 h, showing a lying - down crystal orientation.
[0043] During the thermal annealing and solvent annealing, GIXRD tests were carried out on it. Schematic diagram of solvent annealing is as shown in the appendix Figure 1 , and the crystal orientations of its thermal annealing and solvent annealing are as shown in the appendix Figure 2 . During the thermal annealing and solvent annealing, a reversible transformation of the polymer crystal orientation occurred.
[0044] Example 2
[0045] 5 mg of DPP3T conjugated polymer was added to 0.5 mL of chloroform solvent to prepare a polymer solution with a concentration of 10 mg / mL. It was stirred at 80 °C for at least 6 h until it reached a completely dissolved state. The DPP3T conjugated polymer solution showed a dark blue color. The completely dissolved DPP3T solution was naturally cooled to room temperature. The DPP3T solution cooled to room temperature was transferred onto a square silicon wafer using a pipette and allowed to evaporate naturally to form a uniform thin film, showing a lying - down crystal orientation. Then it was placed in a glove box with an argon atmosphere and subjected to thermal annealing at 230 °C for 3 h, showing a standing - side - by - side crystal orientation. Then the silicon wafer was moved to a closed space with chloroform solvent at the bottom of the container for solvent annealing. The annealing time was 72 h, showing a lying - down crystal orientation. During the thermal annealing and solvent annealing, a reversible transformation of the polymer crystal orientation occurred.
[0046] Example 3
[0047] 1 mg of DPP3T conjugated polymer was added to 0.5 mL of chloroform solvent to prepare a polymer solution with a concentration of 10 mg / mL. It was stirred at 80 °C for at least 6 h until it reached a completely dissolved state. The DPP3T conjugated polymer solution showed a dark blue color. The completely dissolved DPP3T solution was naturally cooled to room temperature. The DPP3T solution cooled to room temperature was transferred to a square silicon wafer by a pipette and naturally dried to form a uniform thin film, showing a lying crystal orientation. Then it was placed in a glove box with an argon atmosphere and subjected to a thermal annealing treatment at 230 °C for 3 h, showing a standing crystal orientation. Then the silicon wafer was moved to a closed space with chloroform solvent at the bottom of the container for solvent annealing. The annealing time was 72 h, showing a lying crystal orientation. During the thermal annealing and solvent annealing processes, the polymer crystal orientation underwent a reversible transformation.
[0048] Example 4
[0049] 5 mg of DPP3T conjugated polymer was added to 0.5 mL of chloroform solvent to prepare a polymer solution with a concentration of 10 mg / mL. It was stirred at 80 °C for at least 6 h until it reached a completely dissolved state. The DPP3T conjugated polymer solution showed a dark blue color. The completely dissolved DPP3T solution was naturally cooled to room temperature. The DPP3T solution cooled to room temperature was transferred to a square silicon wafer by a pipette and naturally dried to form a uniform thin film, showing a lying crystal orientation. Then it was placed in a glove box with an argon atmosphere and subjected to a thermal annealing treatment at 230 °C for 3 h, showing a standing crystal orientation. Then the silicon wafer was moved to a closed space with chloroform solvent at the bottom of the container for solvent annealing. The annealing time was 72 h, showing a lying crystal orientation. During the thermal annealing and solvent annealing processes, the polymer crystal orientation underwent a reversible transformation.
[0050] Example 5
[0051] 5 mg of DPP3T conjugated polymer was added to 0.5 mL of chloroform solvent to prepare a polymer solution with a concentration of 10 mg / mL. It was stirred at 80 °C for at least 6 h until it reached a completely dissolved state. The DPP3T conjugated polymer solution showed a dark blue color. The completely dissolved DPP3T solution was naturally cooled to room temperature. The DPP3T solution cooled to room temperature was transferred to a square silicon wafer by a pipette and naturally dried to form a uniform thin film, showing a lying crystal orientation. Then it was placed in a glove box with an argon atmosphere and subjected to a thermal annealing treatment at 230 °C for 3 h, showing a standing crystal orientation. Then the silicon wafer was moved to a closed space with chloroform solvent at the bottom of the container for solvent annealing. The annealing time was 72 h, showing a lying crystal orientation. During the thermal annealing and solvent annealing processes, the polymer crystal orientation underwent a reversible transformation.
[0052] Example 6
[0053] 5 mg of DPP3T conjugated polymer was added to 0.5 mL of chloroform solvent to prepare a polymer solution with a concentration of 10 mg / mL. It was stirred at 80 °C for at least 6 h until it reached a completely dissolved state. The DPP3T conjugated polymer solution showed a dark blue color. The completely dissolved DPP3T solution was naturally cooled to room temperature. The DPP3T solution cooled to room temperature was transferred to a square silicon wafer by a pipette and naturally dried to form a uniform thin film, showing a lying crystalline orientation. Then it was placed in a glove box with an argon atmosphere and subjected to a thermal annealing treatment at 230 °C for 3 h, showing a standing crystalline orientation. Then the silicon wafer was moved to a closed space with chloroform solvent at the bottom of the container for solvent annealing. The annealing time was 96 h, showing a lying crystalline orientation. During the thermal annealing and solvent annealing processes, the crystalline orientation of the polymer formed a reversible transformation.
[0054] Comparative Example 1
[0055] 5 mg of DPP3T conjugated polymer was added to 0.5 mL of chloroform solvent to prepare a polymer solution with a concentration of 10 mg / mL. It was stirred at 80 °C for at least 6 h until it reached a completely dissolved state. The DPP3T conjugated polymer solution showed a dark blue color. The completely dissolved DPP3T solution was naturally cooled to room temperature. The DPP3T solution cooled to room temperature was transferred to a square silicon wafer by a pipette and naturally dried to form a uniform thin film, showing a lying crystalline orientation. Then it was placed in a glove box with an argon atmosphere and subjected to a thermal annealing treatment at 180 °C for 3 h, showing a lying crystalline orientation, and the crystalline orientation did not change.
[0056] Comparative Example 2
[0057] 5 mg of DPP3T conjugated polymer was added to 0.5 mL of chloroform solvent to prepare a polymer solution with a concentration of 10 mg / mL. It was stirred at 80 °C for at least 6 h until it reached a completely dissolved state. The DPP3T conjugated polymer solution showed a dark blue color. The completely dissolved DPP3T solution was naturally cooled to room temperature. The DPP3T solution cooled to room temperature was transferred to a square silicon wafer by a pipette and naturally dried to form a uniform thin film, showing a lying crystalline orientation. Then it was placed in a glove box with an argon atmosphere and subjected to a thermal annealing treatment at 230 °C for 1 h. The crystal form did not change, showing an obvious lying crystalline orientation.
[0058] Comparative Example 3
[0059] 5 mg of the DPP3T conjugated polymer was added to 0.5 mL of chloroform solvent to prepare a polymer solution with a concentration of 10 mg / mL. It was stirred at 80 °C for at least 6 h until it reached a completely dissolved state. The DPP3T conjugated polymer solution showed a dark blue color. The completely dissolved DPP3T solution was naturally cooled to room temperature. The DPP3T solution cooled to room temperature was transferred to a square silicon wafer by a pipette and naturally dried to form a uniform thin film, showing a lying flat crystal orientation. Then it was placed in a glove box with an argon atmosphere and subjected to a thermal annealing treatment at 230 °C for 3 h, showing a standing upright crystal orientation. Then the silicon wafer was moved to a closed space with chloroform solvent at the bottom of the container for solvent annealing. The annealing time was 24 h respectively, showing a standing upright crystal orientation, and the crystal structure did not change significantly.
[0060] Comparative Example 4
[0061] 5 mg of the DPP3T conjugated polymer was added to 0.5 mL of chloroform solvent to prepare a polymer solution with a concentration of 10 mg / mL. It was stirred at 80 °C for at least 6 h until it reached a completely dissolved state. The DPP3T conjugated polymer solution showed a dark blue color. The completely dissolved DPP3T solution was naturally cooled to room temperature. The DPP3T solution cooled to room temperature was transferred to a square silicon wafer by a pipette and naturally dried to form a uniform thin film. Then it was placed in a glove box with an argon atmosphere and subjected to a thermal annealing treatment at 230 °C for 3 h, showing a standing upright crystal orientation. Then the silicon wafer was moved to a closed space with chloroform solvent at the bottom of the container for solvent annealing. The annealing time was 48 h respectively, and a relatively weak lying flat crystal orientation appeared in the crystal orientation.
[0062] It can be seen from the comparison between the examples and the comparative examples that when the thermal annealing of the DPP3T copolymer is more than 3 h, the crystal orientation on the substrate will change from lying flat to standing upright, and when the solvent annealing of DPP3T is carried out for more than 72 h in the CHCl3 solvent atmosphere, the crystal orientation can change from standing upright to lying flat.
[0063] The above description of the embodiments is for those of ordinary skill in the art to understand and use the invention. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative labor. Therefore, the present invention is not limited to the above embodiments, and the improvements and modifications made by those skilled in the art without departing from the scope of the present invention should be within the protection scope of the present invention.
Claims
1. A method for regulating the crystallization orientation of a pyrrolopyrrole dione donor-acceptor conjugated polymer, characterized in that, The regulation method is as follows: through the alternating operation of thermal annealing and solvent annealing, the molecular chains of the pyrrolopyrrole dione donor-acceptor conjugated polymer are transformed between lying flat and standing upright on the substrate; The process of regulating the crystal orientation includes: Forming a standing upright orientation of the pyrrolopyrrole dione donor-acceptor conjugated polymer through thermal annealing; Realizing the transformation from standing upright to lying flat by placing the pyrrolopyrrole dione donor-acceptor conjugated polymer in a closed atmosphere of chloroform solvent; Repeatedly realizing the reversible transformation process between standing upright and lying flat in this way; The process of regulating the reversible transformation includes: Dissolving the pyrrolopyrrole dione donor-acceptor conjugated polymer in a good solvent, and then naturally cooling and dropping it on a square silicon wafer to form a lying flat crystal orientation; After high-temperature annealing, a standing upright crystal orientation is formed, and then it is placed in a closed space with chloroform solvent for solvent annealing to form a lying flat crystal orientation, thereby forming a reversible transformation of the lying flat and standing upright crystal orientations of the conjugated polymer; The molecular structural formula of the pyrrolopyrrole dione donor-acceptor conjugated polymer is: ； wherein R is an alkyl side chain with a branched structure; The solvent annealing time is 72h - 96h.
2. A method for regulating the crystallization orientation of a pyrrolopyrrole dione donor-acceptor conjugated polymer according to claim 1, characterized in that, The number-average molecular weight of the pyrrolopyrrole dione donor-acceptor conjugated polymer is 18000 - 40000 kg / mol.
3. A method for regulating the crystal orientation of a pyrrolopyrrole dione donor-acceptor conjugated polymer according to claim 1, characterized in that, When through the action of solvent annealing, the alkyl side chain density of the pyrrolopyrrole dione donor-acceptor conjugated polymer is positively correlated with the number of molecules inducing the crystal orientation transformation.
4. A method for regulating the crystallization orientation of a pyrrolopyrrole dione donor-acceptor conjugated polymer according to claim 3, characterized in that, The molecular structural formula of the pyrrolopyrrole dione donor-acceptor conjugated polymer is: 。 5. A method for regulating the crystallization orientation of a pyrrolopyrrole dione donor-acceptor conjugated polymer according to claim 1, characterized in that, The process of regulating the reversible transformation includes: (a) Taking the pyrrolopyrrole dione donor-acceptor conjugated polymer and adding it to chloroform solvent to obtain a DPP3T polymer solution; (b) Heating and stirring the DPP3T polymer solution until it is completely dissolved, and then dropping it on the silicon wafer and naturally evaporating to dryness to form a uniform thin film, thereby forming a lying flat crystal orientation; (c) Using a pipette to transfer and drop the DPP3T polymer solution cooled to room temperature onto a square silicon wafer, and performing high-temperature thermal annealing treatment in an argon atmosphere to form a standing upright crystal orientation. After the annealing is completed, it is placed in a closed space with chloroform vapor atmosphere for solvent annealing treatment to form a lying flat crystal orientation; (d) Placing the silicon wafer after solvent annealing on a hot stage for heating to remove the residual solvent on the surface, thereby forming a reversible transformation of the lying flat and standing upright crystal orientations of the conjugated polymer.
6. A method for regulating the crystallization orientation of a pyrrolopyrrole dione donor-acceptor conjugated polymer according to claim 5, characterized in that, In step (a), the concentration of the DPP3T solution is controlled to 5 - 10 mg / mL by changing the ratio of DPP3T to the solvent; In step (b), the DPP3T polymer solution is heated and stirred at 80 °C for at least 6 h until it is completely dissolved.
7. A method for regulating the crystal orientation of a pyrrolopyrrole dione donor-acceptor conjugated polymer according to claim 5, characterized in that In step (c), the DPP3T polymer solution cooled to room temperature is transferred and dropped onto a square silicon wafer, and high-temperature thermal annealing treatment is performed in an argon atmosphere for 3 - 6 h, and the temperature range is 230 - 270 °C. After the annealing is completed, it is placed in a closed space with chloroform vapor atmosphere for solvent annealing treatment; In step (d), the silicon wafer after solvent annealing is placed on an 80 °C hot stage for heating.