Organic conjugated polymer based on pyrrolo [3, 4-c] pyrrole-1, 4-diketone structural unit as well as preparation method and application of organic conjugated polymer

Abstract

The invention discloses an organic conjugated polymer based on a pyrrolo [3, 4-c] pyrrole-1, 4-diketone structural unit as well as a preparation method and application of the organic conjugated polymer. According to the invention, side chain engineering is utilized, an aromatic group is introduced to one side of pyrrolo [3, 4-c] pyrrole-1, 4-diketone to construct an asymmetric structural unit, and the tensile property is improved. The organic conjugated polymer provided by the invention has a structural formula as shown in a formula I in the specification. # imgabs0 #

Description

Technical Field

[0001] The present invention belongs to the field of organic field effect transistors, and specifically relates to an organic conjugated polymer based on a pyrrolo[3,4-c]pyrrole-1,4-dione structural unit, a preparation method thereof, and an application thereof in stretchable electronic products (such as stretchable organic field effect transistors). Background Art

[0002] With the increasing demand for wearable devices and implantable electronic products, flexible and stretchable electronic products have experienced rapid development in recent years. At present, stretchable organic semiconductors have shown great potential for application in many fields, including wearable devices, displays, and energy storage devices. As an indispensable core component of these electronic products, the organic semiconductor active layer must have excellent electrical properties while taking into account excellent mechanical properties. Over the years, scientists have constructed a variety of strategies from various angles, including structural engineering, elastomer blending, and the development of intrinsically stretchable organic semiconductor materials.

[0003] The development of intrinsically stretchable organic semiconductor materials starts from the design of polymer molecular structure, with the goal of designing materials with intrinsic stretchability, without relying on changes in macroscopic geometric structure, and without blending with elastomers or adding small molecule additives. Therefore, when using such materials to manufacture devices, large-scale preparation can be achieved through solution methods, avoiding complex phase separation processes. Solution methods also provide a variety of methods for regulating the morphology of solid-state films, such as fine-tuning film properties by adjusting parameters such as solution concentration, additive type, and solvent temperature.

[0004] Diketopyrrolopyrrole (DPP) is an important structural unit. Organic polymers based on diketopyrrolopyrrole have long-range π-π conjugated structures and good chemical stability and photostability. The rigid planar structure of its main chain easily promotes the superposition of π-π electron clouds, forming a relatively orderly stacking, which is conducive to achieving higher electron mobility; the side chain provides many 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 the present invention is to provide an organic conjugated polymer based on a pyrrolo[3,4-c]pyrrole-1,4-dione structural unit, and a preparation method and application thereof; the present invention utilizes side chain engineering to introduce an aromatic group on one side of pyrrolo[3,4-c]pyrrole-1,4-dione to construct an asymmetric structural unit, thereby achieving improved tensile properties.

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

[0007]

[0008] In Formula I, R 1 , R 2 , R 3 and R 4 Each independently selected from: C 1 -C 50 A straight chain alkyl group;

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

[0010] x: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 is each independently selected from hydrogen, C 1 -C 50 Alkyl and C 1 -C 50 Any of the alkoxy groups; Represents the connection position of the Ar group in Formula I;

[0014] The Ar is most preferably any one of a thienyl group, a dithienyl group and a thienyl group.

[0015] The present invention also provides a method for preparing the 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 comprises the following steps:

[0017] In an inert atmosphere, in the presence of a catalyst, the compound represented by formula II, the compound represented by formula III and the compound represented by formula IV are subjected to Stille coupling reaction in an organic solvent to obtain an organic conjugated polymer represented by formula I;

[0018]

[0019] In the above formula II, III, and IV, R 1 , R 2 , R 3 , R4 and Ar are defined as R in Formula I 1 , R 2 , R 3 , R 4 and Ar, in Formula IV, Y is a trialkyltin group or a borate group.

[0020] In the above-mentioned preparation method, the gas of the inert atmosphere is nitrogen;

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

[0022] Wherein, the palladium catalyst is selected from tetrakis(triphenylphosphine)palladium and tris(dibenzylideneacetone)dipalladium, and specifically can be tetrakis(triphenylphosphine)palladium;

[0023] The phosphine ligand is selected from at least one of triphenylphosphine, tri-o-tolylphosphine, tri(2-furyl)phosphine and 2-(di-tert-butylphosphino)biphenyl, and specifically can be triphenylphosphine;

[0024] The molar ratio of the compound represented by formula II, the compound represented by formula III, and the compound represented by formula IV is 1:n:n+1, where n is 1 to 10; the molar ratio of the palladium catalyst to the compound represented by formula IV is 0.01-0.1:1, specifically 0.05:1; the molar ratio of the palladium catalyst to the phosphine ligand can be 0.1-0.5:1, specifically 0.25:1;

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

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

[0027] The Stille coupling reaction also includes the following operations: dripping the solution system obtained after the coupling reaction into methanol and filtering to obtain a polymer solid; then extracting the polymer solid with methanol, acetone and n-hexane in sequence, and finally extracting the target product with chloroform and concentrating it by rotary evaporation, and dripping the chloroform containing the target product into methanol for precipitation, and filtering to obtain the final product, which is the organic conjugated polymer shown in formula I.

[0028] The compound represented by the above formula II is prepared by a method comprising the following steps:

[0029] 1) subjecting the compound represented by formula V and the tert-butylbenzeniodonium salt represented by formula VI to an Ullmann-Goldberg reaction in a solvent to obtain a compound represented by formula VII;

[0030]

[0031] In formula V and VII, R 1 , R 2 The definition of R is the same as that of Formula I 1 , R 2 Definition of;

[0032] 2) allowing the compound represented by formula VII to undergo bromination reaction to obtain the compound represented by formula II.

[0033] In step 1) of the above method, the molar ratio of the compound represented by formula V to the compound represented by 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 represented by formula V to CuI can be 1:0.1-1, specifically 1:0.4;

[0035] Reaction using K 2 CO 3 Providing an alkaline environment, the compound represented by formula V and K 2 CO 3 The molar ratio is 1:1-5, specifically 1:3;

[0036] The reaction temperature of the reaction can be 100-150°C, specifically 130°C, and the reaction time can be 12-36h, specifically 24h;

[0037] The solvent is DMF;

[0038] A ligand 4,4'-di-tert-butyl-2,2'-bipyridine is also added into the reaction system; the molar ratio of the compound represented by formula V to the ligand 4,4'-di-tert-butyl-2,2'-bipyridine can be 1:0.8-1.0.

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

[0040] Wherein, the molar ratio of the compound represented by Formula VII to N-bromosuccinimide can be 1:2-3, and the reaction time is about 2-3 hours.

[0041] The organic conjugated polymer of the present invention has excellent tensile properties: high initial strain at break, no decrease in parallel mobility when stretched to 150% once, and the parallel mobility can still be maintained after 3,000 cycles of stretching when the stretching ratio is 100%. No other additives or elastomeric materials need to be added when subsequently applied to flexible devices.

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

[0043] The present invention has the following advantages:

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

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

[0046] 3. The obtained polymer itself has excellent carrier transport performance and solubility, is easy to form a film, and provides convenience for subsequent device processing.

[0047] 4. The obtained polymer itself has good intrinsic stretchability, and no other additives or elastomeric materials need to be added when it is subsequently applied to flexible devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 This is a flow chart for the preparation 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 the present invention 1 H-NMR spectrum.

[0050] Figure 3 is the compound of formula II described in Example 1 of the present invention 13 C-NMR spectrum.

[0051] Figure 4 This is a flow chart for the preparation of the polymer described in Formula I in Example 2 of the present invention.

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

[0053] Figure 6 Optical microscope images of two polymer films, PtBP3DPP4T and PDPP4T, transferred to the PDMS substrate and then stretched to a certain ratio.

[0054] Figure 7 The mobilities of PtBP3DPP4T and PDPP4T polymer films were tested after being stretched to a certain ratio once.

[0055] Figure 8Optical microscope images of the two polymer films, PtBP3DPP4T and PDPP4T, taken after being transferred to the PDMS substrate and stretched to 100%.

[0056] Fig. 9 The mobility of two polymer films, PtBP3DPP4T and PDPP4T, was tested after being transferred to a PDMS substrate and stretched to 100%. DETAILED DESCRIPTION

[0057] The present invention is further described in detail below in conjunction with specific embodiments, and the examples provided are only for illustrating the present invention, rather than for limiting the scope of the present invention. The examples provided below can be used as a guide for further improvements by those of ordinary skill in the art, and do not constitute a limitation of the present invention in any way.

[0058] The experimental methods in the following examples, unless otherwise specified, are all conventional methods, and are performed according to the techniques or conditions described in the literature in the field or according to the product instructions. The materials, reagents, etc. used in the following examples, unless otherwise specified, can all be obtained from commercial channels.

[0059] Example 1. Synthesis of the compound represented by formula II (R 1 C 10 H 21 , R 2 C 12 H 25 )

[0060] The specific reaction step conditions are as follows:

[0061] Chemical reaction flow chart Figure 1 As shown, compound V (1.65 mmol, R 1 C 10 H 21 , R 2 C 12 H 25 ) and compound tert-butylbenzeniodonium salt (2.47 mmol) were dissolved in 50 mL DMF, and then catalyst CuI (0.66 mmol) and base K 2 CO 3 (4.95mmol), ligand 4,4'-di-tert-butyl-2,2'-bipyridine (1.32mmol), react at 130°C in air atmosphere for 24h, stop the reaction, spin dry the reaction system, dry load the sample, and separate the intermediate (0.33mmol, yield: 25.6%) using a silica gel column;

[0062] Then, the intermediate (0.13 mmol) was dissolved in 10 mL of chloroform, and a drop of triethylamine was added. N-bromosuccinimide (0.33 mmol) was added in an ice-water bath, and the reaction was carried out at 30° C. in the dark. Samples were taken every half an hour and the reaction was monitored by thin layer column chromatography. According to the progress of the reaction, an appropriate amount of N-bromosuccinimide was added until the reaction substrate was completely converted into the dibromo product II. The reaction was stopped, the sample was loaded by wet method, and the product (0.12 mmol, yield: 94.5%) was separated by silica gel column.

[0063] The structural confirmation data are as follows:

[0064] 1 H NMR (700 MHz, Benzene-d 6 )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),6.59(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 N 2 O 2 S 2 Br 2 :924.2927; molecular ion peak position: 924.2926.

[0066] From the above, we can see that the product structure is correct.

[0067] Example 2, Synthesis of the polymer represented by formula I (R 1 C 10 H 21 , R 2 C 12 H 25 , R 3 C 10 H 21 , R 4 C 12 H 25 , Ar is a bithiphenyl group)

[0068] Chemical reaction flow chart Figure 4 As shown, the compound II (20.7 μmol) and compound III (62.2 μmol) obtained in Example 1 of the present invention (R 3 C 12 H 25 , R 4 C 10 H 21 ), and 5,5'-bis(trimethylstannyl)-2,2'-bithiophene (82.9 μmol) were dissolved in anhydrous toluene, nitrogen was bubbled for 10 min, catalyst tetrakis(triphenylphosphine)palladium (4.1 μmol) and triphenylphosphine (16.5 μmol) were added to flush the reaction tube and replace it with nitrogen atmosphere, and the reaction was terminated at 110°C for 20 h. After cooling the reaction system to room temperature, it was poured into 100 mL of methanol to precipitate the solid, and filtered. The obtained polymer solid was extracted with methanol, acetone, and n-hexane in turn, and the target product was removed, and finally the target product was extracted with chloroform, the chloroform solution of the target product was concentrated by rotary evaporation, poured into 100 mL of methanol to precipitate the polymer solid, and filtered and dried to obtain polymer I (80.4 mg, yield: 98.6%).

[0069] The structural confirmation data are as follows:

[0070] Elemental analysis: calculated value is C 266 H 394 N 8 O 8 S 16 : C, 73.53; H, 9.14; N, 2.58; S, 11.81; Measured value: C, 73.27; H, 8.91, N, 2.71, S, 11.94.

[0071] It can be seen from the above that the product structure is correct and is a polymer shown in formula I. It is denoted as: PtBP3DPP4T.

[0072]

[0073] Embodiment 3,

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

[0075] The polymer was prepared into a 5 mg / mL chloroform solution for later use. 20 μL of the above solution was taken with a pipette and spin-coated at a speed of 2 kr / min on a 1×1 cm OTS-modified Si / SiO 2 The film was formed on the chip. The PDMS substrate (precursor: cross-linking agent = 15:1, v:v) was lifted up and stretched to different proportions and transferred to the Si / SiO2 pre-printed with 10 μm channel interdigitated gold electrodes. 2After being annealed at 160℃ for 10min, it is used as the active layer of the field effect transistor (the structure of the field effect transistor is as follows Figure 5 or placing the PDMS with polymer I film on a stretching machine and cyclically stretching it for different times at 100% strain, and then closely fitting it on a Si / SiO2 pre-printed with 10 μm channel interdigitated gold electrodes. 2 The transfer was performed on the chip and the mobility was tested after annealing at 160°C for 10 min.

[0076] PDPP4T is a comparative polymer, which is a polymer without adding the asymmetric structural unit shown in Formula II for co-polymerization, and the reaction conditions are the same as those of polymer I (x:y=0:1).

[0077]

[0078] Figure 6 Optical microscope images of two polymer films, PtBP3DPP4T and PDPP4T, transferred to the PDMS substrate and then stretched to a certain ratio.

[0079] Figure 7 The mobilities of PtBP3DPP4T and PDPP4T polymer films were tested after being stretched to a certain ratio once.

[0080] Figure 8 Optical microscope images of the two polymer films, PtBP3DPP4T and PDPP4T, taken after being transferred to the PDMS substrate and stretched to 100%.

[0081] Fig. 9 The mobility of two polymer films, PtBP3DPP4T and PDPP4T, was tested after being transferred to a PDMS substrate and stretched to 100%.

[0082] Depend on Figure 6-Figure 9 It can be seen 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. For those skilled in the art, without departing from the purpose and scope of the present invention, and without the need to carry out unnecessary experimental conditions, the present invention can be implemented in a wide range under equivalent parameters, concentrations and conditions. Although the present invention provides specific embodiments, it should be understood that the present invention can be further improved. In a word, according to the principles of the present invention, the application is intended to include any changes, uses or improvements to the present invention, including departure from the disclosed scope in the application, and changes made with conventional techniques known in the art.

Claims

1. Organic conjugated polymer represented by formula I: In Formula I, R1, R2, R3 and R4 are each independently selected from: C1-C 50 A straight chain alkyl group; Ar is selected from any one of substituted or unsubstituted aryl and heteroaryl, and the bonding mode within the group is selected from a single bond or a double bond; x:y 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 is independently selected from hydrogen, C1-C 50 Alkyl and C1-C 50 Any of the alkoxy groups; represents the connection position of the Ar group in Formula I.

3. The polymer according to claim 2, characterized in that The Ar is any one of a thienyl group, a dithienyl group and a thienyl group.

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

5. The method according to claim 4, characterized in that The gas of the inert atmosphere is nitrogen; The catalyst is composed of a palladium catalyst and a phosphine ligand. Wherein, the palladium catalyst is selected from tetrakis(triphenylphosphine)palladium and tris(dibenzylideneacetone)dipalladium; The phosphine ligand is at least one selected from triphenylphosphine, tri-o-tolylphosphine, tri(2-furyl)phosphine and 2-(di-tert-butylphosphino)biphenyl; The molar ratio of the compound represented by formula II, the compound represented by formula III and the compound represented by formula IV is 1:n:n+1, where n is 1-10.

6. The method according to claim 4, characterized in that The reaction temperature of the Stille coupling reaction is 90-120° C., and the reaction time is 8-24 hours.

7. Use of the organic conjugated polymer represented by formula I as described in any one of claims 1 to 3 as a stretchable organic semiconductor material.

8. The use according to claim 7, characterized in that: Application of organic conjugated polymers shown in formula I in the preparation of organic field effect transistors, organic photovoltaic devices and organic light emitting diodes.

9. The use 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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