Organic conjugated polymers based on pyrrolo[3,4-c]pyrrole-1,4-dione structural units, their preparation methods and applications

Abstract

This invention discloses an organic conjugated polymer based on the pyrrolo[3,4-c]pyrrolo-1,4-dione structural unit, its preparation method, and its applications. This invention utilizes side-chain engineering to introduce aromatic groups onto one side of the pyrrolo[3,4-c]pyrrolo-1,4-dione to construct an asymmetric structural unit, thereby improving tensile properties. The organic conjugated polymer provided by this invention has the following structural formula (Formula I).

Description

Technical Field

[0001] This invention belongs to the field of organic field-effect transistors, specifically relating to a class of organic conjugated polymers based on pyrrolo[3,4-c]pyrrole-1,4-dione structural units, their preparation methods, and their application in stretchable electronic products (such as stretchable organic field-effect transistors). Background Technology

[0002] With the ever-increasing demand for wearable devices and implantable electronics, flexible and stretchable electronics have experienced rapid development in recent years. Currently, stretchable organic semiconductors have demonstrated great potential applications in numerous fields, including wearable devices, displays, and energy storage devices. As an indispensable core component of these electronic products, the active layer of organic semiconductors must possess excellent electrical properties while also maintaining outstanding mechanical properties. Over the years, scientists have developed diverse strategies from various perspectives, including structural engineering, elastomer blending, and the development of intrinsically stretchable organic semiconductor materials.

[0003] The development of intrinsically stretchable organic semiconductor materials begins with polymer molecular structure design, aiming to create materials with intrinsically stretchable properties without relying on changes in macroscopic geometry, blending with elastomers, or adding small-molecule additives. Therefore, when using these materials to fabricate devices, large-area fabrication can be achieved through solution methods, avoiding complex phase separation processes. Solution methods also provide various ways to control the morphology of solid films, such as by adjusting parameters like solution concentration, additive type, and solvent temperature to achieve precise control over film properties.

[0004] Pyrrolopyrroledione (DPP) is an important structural unit. Organic polymers based on DPP possess long-range π-π conjugated structures and good chemical and photostability. The rigid planar structure of its main chain facilitates the superposition of π-π electron clouds, forming a relatively ordered stack, which is beneficial for achieving high electron mobility; the side chains provide numerous possibilities for derivatization. Therefore, DPP and its derivatives are widely used in organic field-effect transistors, organic photovoltaic devices, organic light-emitting diodes, and other fields. Summary of the Invention

[0005] The purpose of this invention is to provide an organic conjugated polymer based on the pyrrolo[3,4-c]pyrrolo-1,4-dione structural unit, its preparation method and application; this invention utilizes side chain engineering to introduce an aromatic group on one side of the pyrrolo[3,4-c]pyrrolo-1,4-dione to construct an asymmetric structural unit, thereby improving tensile properties.

[0006] The organic conjugated polymer based on the pyrrolo[3,4-c]pyrrole-1,4-dione structural unit provided by this invention has the structural formula shown in Formula I:

[0007]

[0008] In Equation I, R1, R2, R3, and R4 are each independently selected from: C1-C 50 Straight-chain alkyl groups;

[0009] Ar is selected from any one of substituted or unsubstituted aryl and heteroaryl groups, and the bonding mode within the group is selected from single bond or double bond;

[0010] The ratio of x to y is 1:1 to 1:10;

[0011] Furthermore, Ar can be selected from any one of the following structural formulas a to l:

[0012]

[0013] R are each independently selected from hydrogen, C1-C 50 Alkyl and C1-C 50 Any one of the alkoxy groups; Indicates the connection position of the Ar group in Formula I;

[0014] The Ar is most preferably any one of thiophene group, bithiophene group, and bisthiophene group.

[0015] The present invention also provides a method for preparing the above-mentioned organic conjugated polymer based on the pyrrolo[3,4-c]pyrrole-1,4-dione structural unit.

[0016] The method for preparing the organic conjugated polymer based on the pyrrolo[3,4-c]pyrrole-1,4-dione structural unit provided by the present invention includes the following steps:

[0017] In an inert atmosphere and in the presence of a catalyst, the compounds shown in Formula II, Formula III, and Formula IV were subjected to Stille coupling reaction in an organic solvent to obtain the organic conjugated polymer shown in Formula I.

[0018]

[0019] In formulas II, III, and IV above, R1, R2, R3, R4, and Ar are defined in the same way as R1, R2, R3, R4, and Ar in formula I. In formula IV, Y is a trialkyltin group or a borate ester group.

[0020] In the above preparation method, the inert atmosphere gas is nitrogen.

[0021] The catalyst is composed of a palladium catalyst and a phosphine ligand.

[0022] The palladium catalyst is selected from tetra(triphenylphosphine)palladium and tris(dibenzylideneacetone)dipalladium, specifically tetra(triphenylphosphine)palladium;

[0023] The phosphine ligand is selected from at least one of triphenylphosphine, trio-tolylphosphine, tris(2-furanyl)phosphine and 2-(di-tert-butylphosphine)biphenyl, and may specifically be triphenylphosphine;

[0024] The molar ratio of the compounds shown in Formula II, Formula III, and Formula IV is 1:n:n+1, where n is 1 to 10; the molar ratio of the palladium catalyst to the compound shown in Formula IV is 0.01-0.1:1, specifically 0.05:1; the molar ratio of the palladium catalyst to the phosphine ligand is 0.1-0.5:1, specifically 0.25:1.

[0025] The reaction temperature of the Stille coupling reaction can be 90–120°C, preferably 110°C, and the reaction time can be 8–24 h, preferably 20 h.

[0026] The organic solvent is selected from at least one of toluene, tetrahydrofuran, and chlorobenzene.

[0027] The Stille coupling reaction is followed by the following steps: the solution system obtained after the coupling reaction is added dropwise to methanol and filtered to obtain a polymer solid; then the polymer solid is extracted sequentially with methanol, acetone and n-hexane; finally, the target product is extracted with chloroform and concentrated by rotary evaporation, and the chloroform containing the target product is added dropwise to methanol to precipitate and filtered to obtain the final product, which is the organic conjugated polymer shown in Formula I.

[0028] The compound shown in Formula II above is prepared by a method comprising the following steps:

[0029] 1) The compound shown in Formula V and the tert-butylbenzeneiodonium salt shown in Formula VI were subjected to an Ullmann-Goldberg reaction in a solvent to obtain the compound shown in Formula VII;

[0030]

[0031] In equations V and VII, the definitions of R1 and R2 are the same as those in equation I;

[0032] 2) The compound shown in Formula VII undergoes a bromination reaction to obtain the compound shown in Formula II.

[0033] In step 1) of the above method, the molar ratio of the compound shown in formula V to the compound shown in formula VI is 1:1 to 1:5, preferably 1:1.5;

[0034] The catalyst used in the reaction is CuI, and the molar ratio of the compound shown in Formula V to CuI can be 1:0.1-1, specifically 1:0.4;

[0035] The reaction uses K2CO3 to provide an alkaline environment, and the molar ratio of the compound shown in Formula V to K2CO3 is 1:1-5, specifically 1:3;

[0036] The reaction temperature can be 100-150℃, specifically 130℃, and the reaction time can be 12-36h, specifically 24h.

[0037] The solvent is DMF;

[0038] The reaction system also includes the ligand 4,4'-di-tert-butyl-2,2'-dipyridine; the molar ratio of the compound shown in Formula V to the ligand 4,4'-di-tert-butyl-2,2'-dipyridine can be 1:0.8-1.0.

[0039] In step 2) of the above method, the bromination reaction is as follows: one drop of triethylamine is added to the chloroform solvent of compound VII, N-bromosuccinimide is added and stirred under ice-water bath conditions, and then the reaction is carried out at room temperature (about 30°C) to obtain compound II.

[0040] The molar ratio of the compound shown in Formula VII to N-bromosuccinimide can be 1:2-3, and the reaction time is approximately 2-3 h.

[0041] The organic conjugated polymer of this invention exhibits excellent tensile properties: high fracture initiation strain, no decrease in parallel migration rate when stretched to 150% in a single cycle, and the parallel migration rate remains unchanged after 3000 cycles of cyclic stretching at a 100% stretch ratio. Therefore, no additional additives or elastomer materials are required for its subsequent application in flexible devices.

[0042] The present invention also provides the application of the organic conjugated polymer shown in Formula I as a stretchable organic semiconductor material. The application is the use of the organic conjugated polymer shown in Formula I in the preparation of organic field-effect transistors, organic photovoltaic devices, and organic light-emitting diodes. Specifically, the organic conjugated polymer shown in Formula I is used to prepare the active layer material of organic field-effect transistors.

[0043] The present invention has the following advantages:

[0044] 1. The synthesis steps are short and easy to produce and purify.

[0045] 2. The obtained polymer has good chemical stability.

[0046] 3. The resulting polymer itself has excellent carrier transport performance and solubility, and is easy to form into a film, which facilitates subsequent device processing.

[0047] 4. The resulting polymer itself has good intrinsic stretchability, and no other additives or elastomer materials need to be added when it is subsequently applied to flexible devices. Attached Figure Description

[0048] Figure 1 This is a flowchart illustrating the preparation process of the compound described in Formula II in Example 1 of the present invention.

[0049] Figure 2 The compound of formula II in Example 1 of this invention 1 H-NMR spectrum.

[0050] Figure 3 The compound of formula II in Example 1 of this invention 13 C-NMR spectrum.

[0051] Figure 4 This is a flowchart illustrating the preparation process of the polymer described in Formula I in Example 2 of the present invention.

[0052] Figure 5 This is a structural diagram of a conjugated polymer field-effect transistor device based on Embodiment 3 of the present invention.

[0053] Figure 6 These are optical microscope images of PtBP3DPP4T and PDPP4T polymer films, respectively, after being transferred onto PDMS substrates and stretched to a certain scale.

[0054] Figure 7 The migration rates were obtained by stretching two polymer films, PtBP3DPP4T and PDPP4T, to a certain ratio in a single operation.

[0055] Figure 8 These are optical microscope images of PtBP3DPP4T and PDPP4T polymer films, respectively, after being transferred onto PDMS substrates and stretched to 100% scale.

[0056] Figure 9 The migration rates were measured after two polymer films, PtBP3DPP4T and PDPP4T, were transferred onto a PDMS substrate and stretched to 100% scale. Detailed Implementation

[0057] The present invention will now be described in further detail with reference to specific embodiments. The given embodiments are merely illustrative of the invention and not intended to limit its scope. The embodiments provided below can serve as a guide for further improvements by those skilled in the art and do not constitute a limitation on the invention in any way.

[0058] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Unless otherwise specified, the materials and reagents used in the following examples are commercially available.

[0059] Example 1: Synthesis of the compound shown in Formula II (R1 is C 10 H 21 R2 is C 12 H 25 )

[0060] The specific reaction steps and conditions are as follows:

[0061] Chemical reaction flow chart as follows Figure 1 As shown, compound V (1.65 mmol, R1 is C) was used. 10 H 21 R2 is C 12 H 25 The compound tert-butylbenzyl iodine salt (2.47 mmol) and the compound were dissolved in 50 mL of DMF. Then, the catalyst CuI (0.66 mmol), the base K2CO3 (4.95 mmol), and the ligand 4,4'-di-tert-butyl-2,2'-dipyridine (1.32 mmol) were added. The reaction was carried out in air at 130 °C for 24 h. The reaction was stopped, the reaction system was dried by rotary evaporation, and the sample was loaded onto the dry surface. The intermediate (0.33 mmol, yield: 25.6%) was obtained by separation by silica gel column chromatography.

[0062] Then, the intermediate (0.13 mmol) was dissolved in 10 mL of chloroform, one drop of triethylamine was added, and N-bromosuccinimide (0.33 mmol) was added in an ice-water bath. The reaction was carried out at 30 °C in the dark. Samples were taken every half hour to monitor the reaction progress using thin-layer column chromatography, and N-bromosuccinimide was added as needed until the substrate was completely converted to dibromo-substituted product II. The reaction was then stopped, and the product (0.12 mmol, yield: 94.5%) was obtained by wet loading and separation using a silica gel column.

[0063] The structural verification data is as follows:

[0064] 1H NMR (700MHz, Benzene-d6) δ (ppm): 9.20 (d, J = 4.2Hz, 1H), 8.99 (d, J = 4.2Hz, 1H), 7.21 (d, J = 8.3Hz, 2H), 7.11 (d, J = 8.3Hz, 2H), 6.61 (d, J = 4.2Hz, 1H), 6.5 9(d,J=4.2Hz,1H),4.03(d,J=7.7Hz,2H),2.10(m,1H),1.47-1.44(m,6H),1. 34-1.25(m,34H),1.13(s,9H),0.92(t,J=7.0Hz,3H),0.92(t,J=7.0Hz,3H).

[0065] MALDI-FTICR-MS m / z:[M] + The calculated value is C 48 H 66 N2O2S2Br2: 924.2927; Molecular ion peak position: 924.2926.

[0066] As can be seen from the above, the structure of the product is correct.

[0067] Example 2: Synthesis of the polymer shown in Formula I (R1 is C 10 H 21 R2 is C 12 H 25 R3 is C 10 H 21 R4 is C 12 H 25 Ar is a bithiophene group.

[0068] Chemical reaction flow chart as follows Figure 4 As shown, compound II (20.7 μmol) and compound III (62.2 μmol) obtained in Example 1 of this invention (R3 is C) 12 H 25 R4 is C 10 H 21), and 5,5'-bis(trimethylsilyl)-2,2'-bithiophene (82.9 μmol) were dissolved in anhydrous toluene, bubbled under nitrogen for 10 min, and then tetra(triphenylphosphine)palladium (4.1 μmol) catalyst was added. Triphenylphosphine (16.5 μmol) was used to purge the reaction tube to replace the nitrogen atmosphere, and the reaction was stopped after 20 h at 110 °C. After cooling the reaction system to room temperature, the solid was precipitated in 100 mL of methanol and filtered. The obtained polymer solid was successively extracted with methanol, acetone, and n-hexane using a Soxhlet extractor to remove the solid. Finally, the target product was extracted with chloroform, and the chloroform solution of the target product was concentrated by rotary evaporation. The polymer solid was precipitated in 100 mL of methanol, filtered, and dried to obtain polymer I (80.4 mg, yield: 98.6%).

[0069] The structural verification data is as follows:

[0070] Elemental analysis: The calculated value is C. 266 H 394 N8O8S 16 :C,73.53;H,9.14;N,2.58;S,11.81;Measured values:C,73.27;H,8.91,N,2.71,S,11.94.

[0071] As can be seen from the above, the structure of the product is correct, and it is the polymer shown in Formula I. It is denoted as: PtBP3DPP4T.

[0072]

[0073] Example 3

[0074] The specific application steps of using the p-type polymer film stretched according to Embodiment 2 of the present invention as the active layer material of a field-effect transistor are as follows:

[0075] A chloroform solution of 5 mg / mL was prepared from the polymer and set aside. 20 μL of this solution was spin-coated onto a 1 × 1 cm OTS-modified Si / SiO2 wafer at 2 kr / min using a pipette. The film was then lifted from a PDMS substrate (precursor:crosslinker = 15:1, v:v) and stretched to different ratios before being transferred onto a Si / SiO2 wafer pre-printed with 10 μm channel gold electrodes. After annealing at 160 °C for 10 min, it was used as the active layer for a field-effect transistor (FET). (The structure of the FET is shown in the figure.) Figure 5 (as shown); or PDMS with a polymer I film is placed on a stretching machine and cyclically stretched at 100% strain for different numbers of times, and then tightly bonded to a Si / SiO2 wafer pre-printed with 10μm channel intercalated gold electrodes for transfer. After annealing at 160℃ for 10 min, the mobility is tested.

[0076] PDPP4T, as a comparative polymer, is a polymer that was not mixed with asymmetric structural units as shown in Formula II, and the reaction conditions were the same as those for polymer I (x:y = 0:1).

[0077]

[0078] Figure 6 These are optical microscope images of PtBP3DPP4T and PDPP4T polymer films, respectively, after being transferred onto PDMS substrates and stretched to a certain scale.

[0079] Figure 7 The migration rates were obtained by stretching two polymer films, PtBP3DPP4T and PDPP4T, to a certain ratio in a single operation.

[0080] Figure 8 These are optical microscope images of PtBP3DPP4T and PDPP4T polymer films, respectively, after being transferred onto PDMS substrates and stretched to 100% scale.

[0081] Figure 9 The migration rates were measured after two polymer films, PtBP3DPP4T and PDPP4T, were transferred onto a PDMS substrate and stretched to 100% scale.

[0082] Depend on Figures 6-9 It is known that the polymer film made from the polymer of the present invention has good stretchability.

[0083] The present invention has been described in detail above. Those skilled in the art will recognize that the invention can be practiced in a wide range of ways with equivalent parameters, concentrations, and conditions without departing from its spirit and scope, and without requiring unnecessary experiments. While specific embodiments have been provided, it should be understood that further modifications can be made to the invention. In summary, according to the principles of the invention, this application is intended to include any changes, uses, or improvements to the invention, including changes made using conventional techniques known in the art that depart from the scope disclosed herein.

Claims

1. The organic conjugated polymer shown in Formula I: In Equation I, R1, R2, R3, and R4 are each independently selected from: C1-C 50 Straight-chain alkyl groups; Ar is selected from any one of substituted or unsubstituted aryl and heteroaryl groups, and the bonding mode within the group is selected from single bond or double bond; The x:y ratio is 1:1 to 1:

10.

2. The polymer according to claim 1, characterized in that, The Ar is selected from any one of the following structural formulas a to l: R are each independently selected from hydrogen, C1-C 50 Alkyl and C1-C 50 Any one of the alkoxy groups; This indicates the connection position of the Ar group in Formula I.

3. The polymer according to claim 2, characterized in that, Ar is any one of thienyl, bithienyl, and denominated thienyl.

4. A method for preparing the polymer according to any one of claims 1-3, comprising the following steps: in an inert atmosphere and in the presence of a catalyst, carrying out a Stille coupling reaction of the compound shown in formula II, the compound shown in formula III and the compound shown in formula IV in an organic solvent to obtain the organic conjugated polymer shown in formula I; In formulas II, III, and IV, R1, R2, R3, R4, and Ar are defined in the same way as R1, R2, R3, R4, and Ar in formula I. In formula IV, Y is a trialkyltin group or a borate ester group.

5. The method according to claim 4, characterized in that, The inert atmosphere is nitrogen. The catalyst is composed of a palladium catalyst and a phosphine ligand. The palladium catalyst is selected from tetra(triphenylphosphine)palladium and tris(dibenzylideneacetone)dipalladium; The phosphine ligand is selected from at least one of triphenylphosphine, tri-o-tolylphosphine, tris(2-furanyl)phosphine and 2-(di-tert-butylphosphine)biphenyl; The molar ratio of the compounds shown in Formula II, Formula III, and Formula IV is 1:n:n+1, where n is 1 to 10.

6. The method according to claim 4, characterized in that, The Stille coupling reaction is carried out at a temperature of 90–120 °C for 8–24 h.

7. The use of the organic conjugated polymer of Formula I as described in any one of claims 1-3 as a stretchable organic semiconductor material.

8. The application according to claim 7, characterized in that, The application of the organic conjugated polymer shown in Formula I in the preparation of organic field-effect transistors, organic photovoltaic devices, and organic light-emitting diodes.

9. The application according to claim 8, characterized in that, The organic conjugated polymer shown in Formula I is used to prepare the active layer material of the device.

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