Chiral conjugated polymer as well as preparation method and application thereof

Abstract

The invention discloses a chiral conjugated polymer as well as a preparation method and application thereof. The structural formula of the polymer is as shown in a formula I, in the formula I, 2, 2-dimethoxy-1, 1-binaphthyl is selected from any one of R configuration and S configuration, R1 is selected from any one of C1-C50 linear or branched alkyl, C1-C50 alkoxy, C7-C50 aralkyl and C5-C50 hetero-alkyl, R2 is selected from any one of C1-C50 alkyl, C1-C50 alkoxy, C7-C50 aralkyl and C5-C50 hetero-alkyl, and R3 is selected from any one of C1-C50 alkyl, C1-C50 alkyl and C5-C50 hetero-alkyl. Ar is selected from any one of aryl, heteroaryl, substituent-containing aryl and substituent-containing heteroaryl, and a bonding mode in the group is selected from at least one of single bond, double bond and triple bond; x: y is 1: (5-15); wherein heteroatoms in the heteroalkyl are at least one of oxygen, sulfur and selenium, and the substitution number of the heteroatoms is 1-10. The polymer is prepared by adopting a carbon-carbon coupling reaction. The chiral conjugated polymer is obtained by introducing a certain proportion of chiral groups, and the specific detection of circularly polarized light of the organic field effect transistor is realized. # imgabs0 #

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials and relates to a chiral conjugated polymer and a preparation method and application thereof. Background Art

[0002] Circularly polarized light (CPL) is a special optical phenomenon in which the endpoints of its electric vector trace a circular path in a plane perpendicular to the direction of propagation. It can be viewed as the superposition of two plane-polarized beams with equal amplitudes, orthogonal vibration directions, and a phase difference of ±π / 2. Circularly polarized light is categorized as left-handed (LCPL) or right-handed (RCPL) depending on the direction of rotation. Circularly polarized light has a wide range of applications in optics and display technology, photography and filters, remote sensing, environmental monitoring, and information encryption and transmission. Detecting circularly polarized light is crucial in scientific experiments and technological applications. For example, it can help improve the precision of optical systems, optimize display technology, and provide greater security in information encryption. Organic field-effect transistors (OFETs) are crucial in detecting circularly polarized light. Through the transistor's signal amplification, they enable highly sensitive detection of circularly polarized light and implement functions such as chirality recognition. Organic semiconductors are key materials for OFETs. However, limited research on circularly polarized light detection using OFETs is currently limited due to the limited development of organic semiconductor materials. Summary of the Invention

[0003] The present invention aims to provide a chiral conjugated polymer, its preparation method, and its application in circularly polarized light detection. By utilizing backbone engineering, the present invention introduces a certain proportion of chiral groups (2,2'-dimethoxy-1,1'-binaphthalene) into the conjugated polymer, resulting in a chiral conjugated polymer that enables specific detection of circularly polarized light using an organic field-effect transistor.

[0004] The present invention provides a polymer, the structural formula of which is shown in Formula I:

[0005] In the formula I, the 2,2´-dimethoxy-1,1´-binaphthyl group is selected from any one of the R configuration and the S configuration, R1 is selected from any one of a C1-C50 straight chain or branched alkyl group, a C1-C50 alkoxy group, a C7-C50 aralkyl group, and a C5-C50 heteroalkyl group; Ar is selected from any one of an aryl group, a heteroaryl group, an aryl group containing a substituent, and a heteroaryl group containing a substituent, and the bonding mode within the group is selected from at least one of a single bond, a double bond, and a triple bond; x:y is 1:5-15; wherein the heteroatom in the heteroalkyl group is at least one of oxygen, sulfur, and selenium, and the number of heteroatom substitutions is 1-10.

[0006] In the above polymer, in Formula I, R1 is selected from a C1-C50 linear or branched alkyl group; Ar is selected from any one of an aryl group, a heteroaryl group, an aryl group containing a substituent, and a heteroaryl group containing a substituent.

[0007] In the above polymer, in the formula I, R1 is selected from a C8-C30 straight or branched alkyl group; In Ar, the aryl group is selected from any one of a monocyclic aryl group, a bicyclic aryl group and a tricyclic aryl group; wherein the heteroaryl group is selected from any one of a monocyclic heteroaryl group, a bicyclic heteroaryl group and a tricyclic heteroaryl group, and the heteroatom in the heteroaryl group is selected from at least one of oxygen, sulfur and selenium; In the aryl group containing a substituent and the heteroaryl group containing a substituent, the substituent is any one of a C1-C50 alkyl group, a C1-C50 alkylthio group, a C1-C50 alkylcarbonyl group, an acyloxy group, a nitrile group and a C1-C50 alkoxy group, and the number of the substituents is an integer of 1 to 4.

[0008] In the above polymer, Ar is selected from any one of the following structural formulas a to u:

[0009] In the above structural formulas a to u, R2 is selected from any one of hydrogen, a C1-C50 straight or branched alkyl group, and a C1-C50 alkoxy group.

[0010] In the structural formulas a to u of the present invention, R2 is selected from any one of hydrogen, a C5-C16 straight-chain or branched alkyl group, and a C5-C16 alkoxy group.

[0011] In the above polymer, in the formula I, the ratio of x:y is 1:10.

[0012] In the present invention, in the formula I, 2,2´-dimethoxy-1,1´-binaphthyl is specifically selected from (R)-6,6´-dibromo-2,2´-dimethoxy-1,1'-binaphthyl or (S)-6,6´-dibromo-2,2´-dimethoxy-1,1´-binaphthyl; R1 is specifically 2-octyldodecyl; Ar is specifically 2,2´-bithiophene; and x:y=1:10.

[0013] The present invention also provides a method for preparing the polymer represented by the above formula I, comprising the following steps: in the presence of an inert atmosphere and a catalyst, subjecting the compound represented by the above formula II, the compound represented by the above formula III, and the compound represented by the above formula IV to a carbon-carbon coupling reaction in an organic solvent to obtain the compound represented by the above formula I;

[0014] In the formula II, III and IV, R1 and Ar are the same as those in the formula I, and Y is a trialkyltin group or a borate group.

[0015] In the above preparation method, the molar ratio of the compound represented by formula II, the compound represented by formula III, and the compound represented by formula IV may be 1:5-15:6-16, specifically 1:10:11, 1:5-11:6-11, 1:10-15:11-16, or 1:7-12:8-13; The molar ratio of the compound represented by formula II to the palladium catalyst and the phosphine ligand may be 1:0.01-1.20:0.03-9.6, specifically 1:0.02:0.08, 1:0.01-0.02:0.03-0.08, 1:0.02-1.20:0.08-9.6 or 1:0.01-1.00:0.03-5.0; The reaction temperature of the carbon-carbon coupling reaction can be 90-110° C., specifically 110° C., and the reaction time can be 24-96 h, specifically 72 h, 24-72 h, 72-96 h or 35-75 h.

[0016] In the above preparation method, 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 at least one of tetrakis(triphenylphosphine)palladium, tris(tri-p-methylphenylphosphine)palladium, tris(dibenzylideneacetone)dipalladium and bis(1,4-diphenylphosphine)butylpalladium dichloride; and the phosphine ligand is selected from at least one of triphenylphosphine, o-tritolylphosphine, tri(2-furyl)phosphine and 2-(di-tert-butylphosphine)biphenyl; The organic solvent is selected from at least one of toluene, o-dichlorobenzene and chlorobenzene; In the formula IV, Y is the trialkyltin-based tin reagent selected from trimethyltin and / or tributyltin.

[0017] In the above-mentioned preparation method, the carbon-carbon coupling reaction further includes the following treatment steps: mixing the system after the carbon-carbon coupling reaction with methanol and filtering to obtain a solid; then washing the solid with methanol, n-hexane and acetone in sequence, and taking the washed solid; finally, extracting the target product from the washed solid with chloroform, and mixing the chloroform and methanol containing the target product, and filtering under reduced pressure to obtain a solid, which is the polymer represented by Formula I.

[0018] The polymer represented by formula I of the present invention is used to prepare an organic field effect transistor device for circularly polarized light detection.

[0019] In the above application, the organic field effect transistor has the ability to respond to ultraviolet-visible-near infrared light in the range of 200-850 nm.

[0020] In the above applications, the organic field-effect transistors specifically include s-synaptic devices and artificial electronic skin devices.

[0021] The present invention also provides a field effect device, comprising a thin film made from the polymer represented by the above formula I.

[0022] The present invention further provides a method for preparing the above-mentioned field effect device, comprising the following steps: dissolving the polymer represented by Formula I in an organic solvent, then spin-coating the polymer on a substrate to obtain a semiconductor polymer film, and then preparing the field effect device; In the above-mentioned method for preparing a field effect device, the organic solvent 1 is specifically selected from at least one of chloroform, o-dichlorobenzene, 1,1,2,2-tetrachloroethane and toluene; The spin coating process is as follows: by controlling the time, rotation speed, and drop amount of the solution spin coating, the solution droplets falling on the substrate are fully distributed on the substrate surface due to the centrifugal force and gravity generated when the substrate rotates; the substrate can be a commonly used substrate known in the art.

[0023] In the above method for preparing the field effect device, the concentration of the polymer represented by Formula I can be 2 mg / mL to 10 mg / mL.

[0024] The present invention has the following beneficial effects: The polymer represented by Formula I provided by the present invention has intrinsic chirality. Organic field-effect transistor devices prepared based on the polymer have excellent carrier transport performance, which is beneficial for the detection of circularly polarized light. At the same time, it is responsive to ultraviolet-visible-near-infrared light in the range of 200 to 850 nm. Field-effect transistors prepared using the polymer can exhibit a specific response to circularly polarized light, which is beneficial for its application in s-synaptic devices and artificial electronic skin devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a method for preparing the polymer R-pDPP4TBN-10 described in Formula I in Example 1 of the present invention.

[0026] Figure 2 This is a method for preparing the polymer S-pDPP4TBN-10 described in Formula I in Example 2 of the present invention.

[0027] Figure 3 Circular dichroism spectra of polymers R-pDPP4TBN-10 and S-pDPP4TBN-10 described in Formula I in Example 3 of the present invention.

[0028] Figure 4The transfer curves of the polymers R-pDPP4TBN-10 and S-pDPP4TBN-10 of Formula I prepared in Example 4 of the present invention are shown in FIG. 1 , wherein: Figure 4 In the figure, a is the transfer curve of polymer R-pDPP4TBN-10, and b is the transfer curve of S-pDPP4TBN-10.

[0029] Figure 5 The graph is a transfer curve change diagram and a polar coordinate diagram of the response current of the polymer R-pDPP4TBN-10 of Formula I prepared in Example 5 of the present invention under circularly polarized light; wherein, Figure 5 In the figure a is the transfer curve change diagram, and in the figure b is the polar coordinate diagram of the response current.

[0030] Figure 6 The graph showing the transfer curve change and the polar coordinate graph of the response current of the polymer S-pDPP4TBN-10 of Formula I prepared in Example 6 under circularly polarized light is shown; wherein, Figure 6 In the figure a is the transfer curve change diagram, and in the figure b is the polar coordinate diagram of the response current. DETAILED DESCRIPTION

[0031] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0032] Unless otherwise specified, the materials and reagents used in the following examples can be obtained from commercial sources.

[0033] Example 1. Synthesis of chiral conjugated polymer represented by formula I In this example, the raw materials used to prepare the chiral conjugated polymer represented by Formula I (the polymer is defined as R-pDPP4TBN-10) are as follows: The compound represented by formula II is specifically (R)-6,6'-dibromo-2,2'-dimethoxy-1,1'-binaphthyl (CAS: 117745-45-6), which is recorded as compound 1; The compound represented by formula III is specifically 2,5-di(2-octyldodecyl)-3,6-dibromodithiophenepyrrolopyrroledione (CAS: 1260685-63-9), R1 is 2-octyldodecyl, and is recorded as compound 2; The compound represented by Formula IV is specifically 5,5'-bis(trimethyltin)-2,2'-dithiophene (CAS: 143367-56-0), Ar is 2,2'-dithiophene, and is recorded as Compound 3.

[0034] Chemical reaction flow chart Figure 1 As shown, the specific reaction conditions of R-pDPP4TBN-10 are as follows: Compounds 1 (4.63 mg), 2 (100 mg), and 3 (53 mg) were dissolved in anhydrous toluene (10 mL). Nitrogen was purged for 20 minutes. The catalyst, tris(dibenzylideneacetone)dipalladium (Pd2(dba)3), 1.97 mg, and the ligand, o-tritolylphosphine (P(o-Tol)3), were added. Nitrogen purging was continued for 20 minutes. The reaction was carried out at 100°C under nitrogen protection for 72 hours. After cooling to room temperature, the reaction system was poured into 100 mL of methanol. The precipitated solid was filtered. The resulting solid was extracted with methanol, n-hexane, and acetone in that order using a Soxhlet extractor to remove the catalyst, unreacted starting materials, and oligomers. Finally, the target product was extracted with chloroform. The chloroform solution containing the target product was then poured into 200 mL of methanol. The precipitated solid was filtered to obtain the final product, R-pDPP4TBN-10 (90 mg, 86% yield). The structural confirmation data are as follows: Proton spectrum: 1 H NMR (500 MHz, CDCl2CDCl2, 373 K) δ 8.92 (s, 2 H), 8.09 (d, J =37.9 Hz, 0.4H), 7.53 (s, 0.4H), 7.35 – 6.84 (m, 5.8H), 4.25 – 3.68 (m, 4.6H), 2.05 (s, 2H), 2.02 – 0.15 (m, 76H); Molecular weight: M w / M n (GPC) = 119 / 65 kg mol -1 ; From the above, it can be seen that the structure of the above product is correct, which is the polymer R-pDPP4TBN-10 represented by formula I (specifically, in formula I, R1 is 2-octyldodecyl; Ar is 2,2´-dithiophene; x:y=1:10).

[0035] Example 2: Synthesis of Chiral Conjugated Polymers Represented by Formula I In this embodiment, the raw materials used to prepare the chiral conjugated polymer represented by formula I (polymer is defined as) are as follows: The compound represented by formula II is specifically (S)-6,6'-dibromo-2,2'-dimethoxy-1,1'-binaphthyl (CAS: 74866-27-6), which is recorded as compound 4; The compound represented by formula III and the compound represented by formula IV are the same as those in Example 1 of the present invention and are respectively recorded as compounds 2 and 3.

[0036] Chemical reaction flow chart Figure 2As shown, the specific reaction step conditions of S-pDPP4TBN-10 are as follows: Compounds 4 (4.63 mg), 2 (100 mg), and 3 (53 mg) were dissolved in anhydrous toluene (10 mL) and nitrogen was purged for 20 minutes. The catalyst, tris(dibenzylideneacetone)dipalladium (1.97 mg), and the ligand, o-tritolylphosphine (2.62 mg), were added and nitrogen purging continued for another 20 minutes. The reaction was carried out at 100°C under nitrogen protection for 72 hours. After cooling to room temperature, the reaction system was poured into 100 mL of methanol, and the precipitated solid was filtered. The resulting solid was extracted with methanol, n-hexane, and acetone in that order using a Soxhlet extractor to remove the catalyst, unreacted starting materials, and oligomers. Finally, the target product was extracted with chloroform. The chloroform solution containing the target product was then poured into 200 mL of methanol, and the precipitated solid was filtered to obtain the final product, S-pDPP4TBN-10 (91 mg, 87% yield). The structural confirmation data are as follows: Proton spectrum: 1 H NMR (500 MHz, CDCl2CDCl2, 373 K): δ 8.90 (s, 2H), 8.05 (d, J =37.9 Hz, 0.4H), 7.53 (s, 0.4H), 7.35 – 6.84 (m, 5.8H), 4.25 – 3.68 (m, 4.6H), 2.05 (s, 2H), 1.48 – 0.89(m, 76H). Molecular weight: M w / M n (GPC) = 139 / 74 kg mol -1 . From the above, it can be seen that the structure of the above product is correct, which is the polymer S-pDPP4TBN-10 represented by Formula I (specifically, in Formula I, R1 is 2-octyldodecyl; Ar is 2,2'-dithiophene; x:y=1:10).

[0037] Example 3, Circular dichroism spectra of polymers R-pDPP4TBN-10 and S-pDPP4TBN-10 described in Formula I of the present invention: The polymers R-pDPP4TBN-10 and S-pDPP4TBN-10 prepared in Examples 1 and 2 of the present invention were dissolved in various organic solvents, including chloroform, o-dichlorobenzene, 1,1,2,2-tetrachloroethane, and other solvents, such as toluene. The polymers R-pDPP4TBN-10 and S-pDPP4TBN-10 of the present invention have good solubility in chlorinated solvents (such as chloroform, o-dichlorobenzene, 1,1,2,2-tetrachloroethane) (the solubility is about 15 mg / mL at room temperature (25°C)). A high-quality thin film was prepared by spin coating the chloroform solution of the polymers R-pDPP4TBN-10 and S-pDPP4TBN-10 shown in Formula I (the drop volume was 200 microliters, the rotation speed was 3000 rpm, and the time was 1 minute) onto a quartz wafer. The thin films were subjected to circular dichroism spectroscopy tests, and the results were as follows: Figure 3 As shown. Figure 3 It can be seen that the chiral conjugated polymers R-pDPP4TBN-10 and S-pDPP4TBN-10 exhibit symmetric circular dichroism (CD) signals in the wavelength range of 200 nm to 900 nm, showing the Cotton effect.

[0038] It can be seen from the above that the polymers R-pDPP4TBN-10 and S-pDPP4TBN-10 described in Formula I of the present invention are chiral conjugated polymers.

[0039] Example 4: Preparation of field effect devices of polymers R-pDPP4TBN-10 and S-pDPP4TBN-10: According to the method described in the literature (Chem. Rev. 2012, 112, 2208-2267), a 300 nm thick layer of silicon dioxide was deposited on single-crystalline silicon. The film was then gold-plated using photolithography to a width of 1440 μm and a length of 50 μm. The film was then modified with a monolayer of octadecyltrichlorosilane. The polymers R-pDPP4TBN-10 and S-pDPP4TBN-10 (3 mg) prepared in Examples 1 and 2 of the present invention were dissolved in 1 mL of o-dichlorobenzene and spin-coated onto the modified film. After vacuum annealing at 100°C, a polymer field-effect device was prepared, and its electrical properties were tested. The corresponding transfer curve is as follows Figure 4 As shown by Figure 4 The results show that the transistor devices prepared from the polymers R-pDPP4TBN-10 and S-pDPP4TBN-10 of the present invention exhibit hole transport properties. Among them, the maximum and average hole mobility of the device based on R-pDPP4TBN-10 reached 0.12 cm 2 ·V -1 ·s -1 and 0.11 cm2 ·V -1 s -1 , the average on-off ratio is 1.2×10 5 The maximum and average hole mobility of the device based on S-pDPP4TBN-10 reached 0.11 cm 2 ·V -1 ·s -1 and 0.10 cm 2 ·V -1 ·s -1 , the average on / off ratio is 2.9×10 5 , the average threshold voltage is -2 V.

[0040] From the above, it can be seen that the polymers R-pDPP4TBN-10 and S-pDPP4TBN-10 of the present invention exhibit semiconductor properties, laying a foundation for circularly polarized light detection.

[0041] Example 5. Changes in transfer curve and polar coordinates of response current of polymer R-pDPP4TBN-10 represented by formula I under circularly polarized light Based on the organic field effect transistor device prepared in Example 4 of the present invention, left-handed and right-handed circularly polarized light detection was performed on the polymer R-pDPP4TBN-10. Figure 5 As shown in middle a, the transistor device based on R-pDPP4TBN-10 exhibited significant photoresponse differences under left-handed circularly polarized light and right-handed circularly polarized light (808 nm, 3.4 mW cm -2 , V G = -5V, V DS = -60V), where the photocurrent under right-handed circularly polarized light is higher than that under left-handed circularly polarized light. Further photoresponse (R) calculations show that the device prepared with the polymer R-pDPP4TBN-10 of the present invention has an R value of 1.14 AW under right-handed polarized light. -1 , while under left-handed polarized light, the R value is 0.83 AW -1 The difference between the two shows good circular polarization response and discrimination ability. The circular polarization response test was further carried out by changing the polarization state of the incident light, such as Figure 5 As shown in Figure 2(b), the R-pDPP4TBN-10 device can measure the ellipticity of the incident light beam.

[0042] From the above, it can be seen that the polymer R-pDPP4TBN-10 represented by formula I of the present invention can distinguish right-handed polarized light from left-handed polarized light, has a better response to right-handed polarized light, and can achieve specific detection of circularly polarized light.

[0043] Example 6: Changes in transfer curve and polar coordinates of response current of the polymer S-pDPP4TBN-10 described in Formula I under circularly polarized light Based on the organic field effect transistor device prepared in Example 4 of the present invention, left-handed and right-handed circularly polarized light detection was performed on the polymer S-pDPP4TBN-10. Figure 6 As shown in middle a, the transistor device based on S-pDPP4TBN-10 exhibits significant photoresponse differences under left-handed circularly polarized light and right-handed circularly polarized light (808 nm, 3.4 mW cm −2， V G = -5V, V DS = -60V), where the photocurrent under left-handed circularly polarized light is higher than that under right-handed circularly polarized light. Further calculation of the photoresponse (R) shows that the device prepared from the polymer S-pDPP4TBN-10 of the present invention has an R value of 1.16 AW under left-handed polarized light. -1 , while the R value is 0.84 AW under right-hand polarized light -1 The difference between the two shows good circular polarization response and discrimination ability. The circular polarization response test was further carried out by changing the polarization state of the incident light, such as Figure 6 As shown in b, the device prepared from the polymer S-pDPP4TBN-10 of the present invention can measure the ellipticity of the incident light beam.

[0044] As can be seen from the above, the polymer S-pDPP4TBN-10 represented by formula I of the present invention can distinguish right-handed polarized light from left-handed polarized light, has a better response to left-handed polarized light, and can achieve specific detection of circularly polarized light.

Claims

1. A polymer having the structural formula shown in Formula I: In the formula I, 2,2'-dimethoxy-1,1'-binaphthyl is selected from any one of R configuration and S configuration, R1 is selected from any one of C1-C50 straight chain or branched alkyl, C1-C50 alkoxy, C7-C50 aralkyl and C5-C50 heteroalkyl; Ar is selected from any one of aryl, heteroaryl, aryl containing a substituent and heteroaryl containing a substituent, and the bonding mode within the group is selected from at least one of a single bond, a double bond and a triple bond; x:y is 1:5-15; wherein, The heteroatom in the heteroalkyl group is at least one of oxygen, sulfur and selenium, and the number of heteroatom substitutions is 1 to 10.

2. The polymer according to claim 1, characterized in that In the formula I, R1 is selected from a C1-C50 straight-chain or branched alkyl group; Ar is selected from any one of an aryl group, a heteroaryl group, an aryl group containing a substituent, and a heteroaryl group containing a substituent.

3. The polymer according to claim 1 or 2, characterized in that In the formula I, R1 is selected from a C8-C30 straight or branched alkyl group; In Ar, the aryl group is selected from any one of a monocyclic aryl group, a bicyclic aryl group and a tricyclic aryl group; wherein the heteroaryl group is selected from any one of a monocyclic heteroaryl group, a bicyclic heteroaryl group and a tricyclic heteroaryl group, and the heteroatom in the heteroaryl group is selected from at least one of oxygen, sulfur and selenium; In the aryl group containing a substituent and the heteroaryl group containing a substituent, the substituent is any one of a C1-C50 alkyl group, a C1-C50 alkylthio group, a C1-C50 alkylcarbonyl group, an acyloxy group, a nitrile group and a C1-C50 alkoxy group, and the number of the substituents is an integer of 1 to 4.

4. The polymer according to any one of claims 1 to 3, characterized in that The Ar is selected from any one of the following structural formulas a to u: In the above structural formulas a to u, R2 is selected from any one of hydrogen, a C1-C50 straight or branched alkyl group, and a C1-C50 alkoxy group.

5. The polymer according to any one of claims 1 to 4, characterized in that In the formula I, x:y is 1:

10.

6. A method for preparing the polymer of formula I according to any one of claims 1 to 5, comprising the steps of: subjecting the compound of formula II, the compound of formula III, and the compound of formula IV to a carbon-carbon coupling reaction in an organic solvent in the presence of an inert atmosphere and a catalyst to obtain the compound of formula I; In the formula II, III and IV, R1 and Ar are the same as those in the formula I, and Y is a trialkyltin group or a borate group.

7. The preparation method according to claim 6, characterized in that The molar ratio of the compound represented by formula II, the compound represented by formula III, and the compound represented by formula IV is 1:5-15:6-16; The molar ratio of the compound represented by formula II to the palladium catalyst and the phosphine ligand is 1:0.01-1.20:0.03-9.6; The reaction temperature of the carbon-carbon coupling reaction is 90-110° C., and the reaction time is 24-96 hours.

8. The preparation method according to claim 6 or 7, 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 at least one of tetrakis(triphenylphosphine)palladium, tris(tri-p-methylphenylphosphine)palladium, tris(dibenzylideneacetone)dipalladium and bis(1,4-diphenylphosphine)butylpalladium dichloride; and the phosphine ligand is selected from at least one of triphenylphosphine, o-tritolylphosphine, tri(2-furyl)phosphine and 2-(di-tert-butylphosphine)biphenyl; The organic solvent is selected from at least one of toluene, o-dichlorobenzene and chlorobenzene; In the formula IV, Y is the trialkyltin-based tin reagent selected from trimethyltin and / or tributyltin.

9. The preparation method according to any one of claims 6 to 8, characterized in that After the carbon-carbon coupling reaction, the following treatment steps are also included: mixing the system after the carbon-carbon coupling reaction with methanol and filtering to obtain a solid; then washing the solid with methanol, n-hexane and acetone in sequence, and taking the washed solid; finally, extracting the target product from the washed solid with chloroform, and mixing the chloroform containing the target product with methanol, and filtering under reduced pressure to obtain a solid, which is the polymer represented by Formula I.

10. Use of the polymer represented by formula I according to any one of claims 1 to 5 in the preparation of an organic field effect transistor device for circularly polarized light detection.

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