An electron donor-acceptor conjugated polymer and a preparation method and application thereof

Abstract

The application discloses an electron donor-acceptor conjugated polymer and a preparation method and application thereof. The polymer adopts carbazole with an oligoether chain or an alkyl chain as an electron donor unit, adopts anthraquinone as an electron acceptor unit, and adopts an alkynyl group as an electron bridge to realize the connection of the electron donor unit and the electron acceptor unit. Under light irradiation, the electron bridge and the electron acceptor can be active sites for oxygen reduction after obtaining electrons, and can selectively reduce oxygen into hydrogen peroxide, so the electron donor-acceptor conjugated polymer is an excellent photocatalyst and can improve the yield of photocatalytic hydrogen peroxide production.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of photocatalysis, more particularly, to an electron donor-acceptor conjugated polymer, a preparation method and application thereof, and a strategy for improving the photocatalytic yield of hydrogen peroxide based on the polymer. BACKGROUND

[0002] Hydrogen peroxide, as a chemical with a key position in modern industry and life, plays an irreplaceable role in many fields such as medical disinfection, wastewater treatment, and energy storage. However, the traditional industrial production of anthraquinone oxidation not only consumes a huge amount of energy, but also produces toxic by-products in the production process, limiting its sustainable development. Photocatalytic synthesis of hydrogen peroxide uses water and oxygen, which are abundant on earth and can be regenerated sustainably, as raw materials, which conforms to the concept of green chemistry and sustainable development. Currently, in the research of photocatalytic synthesis of hydrogen peroxide, organic photocatalysts can flexibly adjust the photophysical and photochemical processes in the photocatalytic synthesis of hydrogen peroxide by designing and regulating the molecular structure, thereby optimizing the catalytic performance. However, the low generation rate of photo-generated carriers, high exciton binding energy, and low hydrogen peroxide yield limit the further development and practical application of organic photocatalysts. Therefore, developing organic photocatalysts with high photo-generated carrier generation and separation ability, low exciton binding energy, and high hydrogen peroxide yield is the key challenge and research focus in this field.

[0003] Chinese patent CN113145167A discloses an electron donor-acceptor conjugated polymer, a preparation method and application thereof. The polymer photocatalyst is prepared by Suzuki polymerization reaction with a boronic acid-based monomer having an electron donor unit structure and a dibromide monomer having an electron acceptor unit structure. When the electron donor-acceptor conjugated polymer is dispersed in pure water and irradiated with simulated sunlight with a light power of 100 mW / cm 2 , the highest yield of hydrogen peroxide is 1400 μmol·g -1 ·h -1 ·h SUMMARY

[0004] The primary object of the present application is to overcome the problem of low hydrogen peroxide yield when using the existing electron donor-acceptor conjugated polymer as a photocatalyst for synthesizing hydrogen peroxide, and to provide an electron donor-acceptor conjugated polymer to improve the yield of photocatalytic hydrogen peroxide production.

[0005] A further object of the present application is to provide a preparation method of an electron donor-acceptor conjugated polymer.

[0006] Another object of the present application is to provide the use of the above-mentioned electron donor-acceptor conjugated polymer.

[0007] The above-mentioned object of the present application is achieved by the following technical solutions.

[0008] An electron donor-acceptor conjugated polymer has the following structure shown in formula (I):

[0009] Formula (I);

[0010] wherein, is an electron donor unit; is an electron acceptor unit; is an electron bridge; the polymerization degree n = 1-100;

[0011] The electron donor unit is formula (a-1) or (a-2);

[0012] Formula (a-1); Formula (a-2);

[0013] In formula (a-2), R is a linear alkyl group with 12-14 carbon atoms;

[0014] The electron acceptor unit is formula (b):

[0015] Formula (b);

[0016] The electron bridge is ;

[0017] The P represents a site connected with the electron acceptor unit, the m represents a site connected with the electron donor unit, and the J and K represent sites connected with the electron bridge.

[0018] The present application discloses a conjugated polymer with an electron donor-electron acceptor alternating connection structure, wherein the electron donor and the electron acceptor are connected through an alkynyl electron bridge, the electron donor unit is a carbazole with an oligoether chain or an alkyl chain, and the electron acceptor unit is anthraquinone.

[0019] The electron donor-acceptor conjugated polymer of the present application can serve as an active site for oxygen reduction under light irradiation, and can selectively reduce oxygen into hydrogen peroxide, so it is an excellent photocatalyst and can improve the yield of photocatalytic hydrogen peroxide production.

[0020] The catalyst of the present application introduces an oligoether chain at the electron donor carbazole group, and the electronic effect and steric effect of the oligoether chain effectively adjust the structure of the electron donor, so as to promote more excitons to dissociate into photo-generated carriers, and further improve the yield of photocatalytic hydrogen peroxide production when the obtained electron donor-acceptor conjugated polymer is used as a photocatalyst.

[0021] The catalyst of the present application can promote more excitons to dissociate into photo-generated carriers by introducing linear alkyl with carbon number of 12-14 at the electron donor carbazole group, thereby improving the yield of photo-catalytic production of hydrogen peroxide when the obtained electron donor-acceptor conjugated polymer is used as a photo-catalyst.

[0022] Preferably, the electron donor-acceptor conjugated polymer has the structure shown in the following formula (II):

[0023] Formula (II).

[0024] Preferably, the electron donor-acceptor conjugated polymer has the structure shown in the following formula (III):

[0025] Formula (III).

[0026] The present application also protects the preparation method of the electron donor-acceptor conjugated polymer shown in the above formula (II), comprising the following steps:

[0027] obtaining and obtaining the electron donor-acceptor conjugated polymer with the structure shown in formula (II) through polymerization reaction.

[0028] Preferably, in the preparation method of the electron donor-acceptor conjugated polymer shown in formula (II), obtained by reaction of 1,3,6,8-tetrabromo-9H-carbazole and 1-bromo-2-(2-methoxyethoxy)ethane.

[0029] Preferably, in the preparation method of the electron donor-acceptor conjugated polymer shown in formula (II), and obtaining the electron donor-acceptor conjugated polymer with the structure shown in formula (II) by reaction in the presence of a palladium catalyst, cuprous iodide and a base.

[0030] Preferably, in the preparation method of the electron donor-acceptor conjugated polymer shown in formula (II), and the molar ratio of 1: (4.05-4.2).

[0031] Preferably, in the preparation method of the electron donor-acceptor conjugated polymer shown in formula (II), the palladium catalyst can be tetrakis(triphenylphosphine)palladium and / or bis(triphenylphosphine)palladium chloride.

[0032] Preferably, in the preparation method of the electron donor-acceptor conjugated polymer shown in formula (II), the base is one or more of triethylamine, sodium carbonate, potassium carbonate.

[0033] Preferably, in the preparation method of the electron donor-acceptor conjugated polymer shown in formula (II), the reaction temperature is 70-90 DEG C, and the reaction time is 24-48 hours.

[0034] Preferably, in the preparation method of the electron donor-acceptor conjugated polymer shown in formula (II), the reaction atmosphere is inert atmosphere. Specifically, the reaction atmosphere is nitrogen atmosphere and / or argon atmosphere.

[0035] Preferably, in the preparation method of the electron donor-acceptor conjugated polymer shown in formula (II), the reaction is carried out in an organic solvent, and the organic solvent is one or more of dimethylacetamide, N-methylpyrrolidone and dimethylformamide.

[0036] Preferably, in the preparation method of the electron donor-acceptor conjugated polymer shown in formula (II), after the reaction, a post-treatment operation can be further included, and the post-treatment operation includes ultrasonic, centrifugation, washing and vacuum drying in sequence.

[0037] The application also protects the preparation method of the electron donor-acceptor conjugated polymer shown in formula (III) above, which comprises the following steps:

[0038] The compound shown in formula (III) is prepared through a polymerization reaction. The compound shown in formula (III) is prepared through a polymerization reaction. The compound shown in formula (III) is prepared through a polymerization reaction.

[0039] Preferably, in the preparation method of the electron donor-acceptor conjugated polymer shown in formula (III), The compound shown in formula (III) is obtained through reaction of 1,3,6,8-tetrabromo-9H-carbazole and 1-bromotridecane.

[0040] Preferably, in the preparation method of the electron donor-acceptor conjugated polymer shown in formula (III), The compound shown in formula (III) is obtained through reaction in the presence of a palladium catalyst, cuprous iodide and a base. Preferably, in the preparation method of the electron donor-acceptor conjugated polymer shown in formula (III),

[0041] The molar ratio of the compound shown in formula (III) to the compound shown in formula (II) is 1: (4.05-4.2). Preferably, in the preparation method of the electron donor-acceptor conjugated polymer shown in formula (III), the palladium catalyst can be tetrakis(triphenylphosphine)palladium and / or bis(triphenylphosphine)palladium chloride.

[0042] Preferably, in the preparation method of the electron donor-acceptor conjugated polymer shown in formula (III), the base is one or more of triethylamine, sodium carbonate and potassium carbonate.

[0043] Preferably, in the preparation method of the electron donor-acceptor conjugated polymer shown in formula (III), the base is one or more of triethylamine, sodium carbonate and potassium carbonate.

[0044] ​Preferably, in the preparation method of the electron donor-acceptor conjugated polymer shown in formula (III), the reaction temperature is 70-90 DEG C, and the reaction time is 24-48 hours.

[0045] Preferably, in the preparation method of the electron donor-acceptor conjugated polymer shown in formula (III), the reaction atmosphere is inert atmosphere.

[0046] Preferably, in the preparation method of the electron donor-acceptor conjugated polymer shown in formula (III), the reaction is carried out in an organic solvent, and the organic solvent is one or more of dimethylacetamide, N-methylpyrrolidone and dimethylformamide.

[0047] Preferably, in the preparation method of the electron donor-acceptor conjugated polymer shown in formula (III), after the reaction, a post-treatment operation can be further included, and the post-treatment operation includes ultrasonic, centrifugation, washing and vacuum drying in sequence.

[0048] The application also protects the application of the electron donor-acceptor conjugated polymer of any one of the above in the production of hydrogen peroxide by photocatalysis as a photocatalyst.

[0049] The application also protects the application of the electron donor-acceptor conjugated polymer of any one of the above in promoting the generation of photo-generated carriers as a photocatalyst.

[0050] The application also protects the application of the electron donor-acceptor conjugated polymer of any one of the above in reducing the exciton binding energy as a photocatalyst.

[0051] The application also protects a method for producing hydrogen peroxide by photocatalysis, which comprises the following steps: adding the electron donor-acceptor conjugated polymer of any one of the above into water, and generating hydrogen peroxide by irradiation.

[0052] Compared with the prior art, the application has the following beneficial effects:

[0053] The application discloses a conjugated polymer with an electron donor-electron acceptor alternating connection structure, wherein the electron donor and the electron acceptor are connected through an alkyne group electronic bridge, the electron donor unit is carbazole with an oligoether chain or an alkyl chain, and the electron acceptor unit is anthraquinone.

[0054] The electron donor-acceptor conjugated polymer of the application can be used as an active site for oxygen reduction under irradiation, and can selectively reduce oxygen into hydrogen peroxide, is an excellent photocatalyst, and can improve the yield of hydrogen peroxide produced by photocatalysis. BRIEF DESCRIPTION OF DRAWINGS

[0055] Figure 1 The nuclear magnetic resonance (NMR) of the electron donor-acceptor conjugated polymer of Example 1, Example 2 and Comparative Example 1 is shown in the following table. 13C-NMR) spectrum.

[0056] Figure 2 is a diffuse reflectance infrared spectrogram of the electron donor-acceptor conjugated polymer of Example 1, Example 2 and Comparative Example 1.

[0057] Figure 3 is a Raman spectrum of the electron donor-acceptor conjugated polymer of Example 1, Example 2 and Comparative Example 1.

[0058] Figure 4 is an XRD graph of the electron donor-acceptor conjugated polymer of Example 1, Example 2 and Comparative Example 1.

[0059] Figure 5 is a scanning electron microscope characterization graph of the electron donor-acceptor conjugated polymer of Example 1, Example 2 and Comparative Example 1.

[0060] Figure 6 is a transmission electron microscope characterization graph of the electron donor-acceptor conjugated polymer of Example 1, Example 2 and Comparative Example 1.

[0061] Figure 7 is a transient photocurrent response characterization graph of the electron donor-acceptor conjugated polymer of Example 1, Example 2 and Comparative Example 1 under argon atmosphere.

[0062] Figure 8 is a variable-temperature photoluminescence spectrum of the electron donor-acceptor conjugated polymer of Example 1, Example 2 and Comparative Example 1.

[0063] Figure 9 is a variable-temperature photoluminescence intensity versus temperature graph of the electron donor-acceptor conjugated polymer of Example 1, Example 2 and Comparative Example 1. DETAILED DESCRIPTION

[0064] In order to more clearly, completely describe the technical solutions of the present application, the present application is further described in detail below through specific examples, and it should be understood that the specific examples described herein are only used to explain the present application, and are not used to limit the present application, and various changes can be made within the scope of the present application.

[0065] Example 1

[0066] An electron donor-acceptor conjugated polymer has the following structure shown in formula (II):

[0067] Formula (II).

[0068] The preparation method of the above-mentioned electron donor-acceptor conjugated polymer comprises the following steps:

[0069] Step S1. 100 mg of 1,3,6,8-tetrabromo-9H-carbazole and 149 mg of potassium carbonate were added to 5 mL of N,N-dimethylformamide, and after stirring at room temperature for 30 minutes, 20 mg of 1-bromo-2-(2-methoxyethoxy)ethane was added. After 12 h of reaction, a white precipitate was obtained, and the monomer product was obtained by filtration. The structural formula is as follows:

[0070] .

[0071] 1 H NMR (400 MHz, Chloroform- d ) δ 8.07 (d, J = 4 Hz, 2H), 7.81 (d, J =2 Hz, 2H), 5.43-5.46 (m, 2H), 3.79-3.83 (m, 2H), 3.47-3.50 (m, 2H), 3.34-3.37(m, 2H), 3.26 (s, 3H).

[0072] Step S2. The monomer prepared in step S1 (50 mg) and 2,6-diethynyl-9,10-anthracenedione (96 mg) were dissolved in 8 mL of dimethylformamide (DMF) under an argon atmosphere. (PPh)2PdCl2(27 mg), CuI (3.5 mg), and triethylamine (8 mL) were added to the solution. The reaction mixture was stirred at 80°C for 48 h. After cooling, ultrasonic treatment in DMF for 30 min was performed, followed by centrifugation and ultrasonic washing with ethanol for 3 times. Then the catalyst was filtered and dried under vacuum at 60°C to obtain an electron donor-acceptor conjugated polymer represented by formula (II), named PEG-alky-AQ. Analysis showed that the polymer degree of polymerization was distributed in 1-100.

[0073] Example 2

[0074] An electron donor-acceptor conjugated polymer has the following structure represented by formula (III):

[0075] Formula (III).

[0076] The preparation method of the above-mentioned electron donor-acceptor conjugated polymer comprises the following steps:

[0077] Step S1. 100 mg of 1,3,6,8-tetrabromo-9H-carbazole and 149 mg of potassium carbonate were added to 5 mL of N,N-dimethylformamide, and after stirring at room temperature for 30 minutes, 20 mg of 1-bromo-2-(2-methoxyethoxy)ethane was added. After 12 h of reaction, a white precipitate was obtained, and the monomer product was obtained by filtration. The structural formula is as follows:

[0078] .

[0079] 1 H NMR (600 MHz, Chloroform- d ) δ 8.07 (d, J = 6 Hz, 2H), 7.81 (d, J =6 Hz, 2H), 5.11-5.16 (m, 2H), 1.80 (t, J = 24 Hz, 2H), 1.27 (s, 20H), 0.90(t, J = 18 Hz, 3H).

[0080] Step S2. The monomer prepared in step S1 (50 mg) and 2,6-diethynyl-9,10-anthracenedione (90 mg) were dissolved in 8 mL dimethylformamide (DMF) under argon atmosphere. (PPh)2PdCl2(27 mg), Cul (3.5 mg), triethylamine (8 mL) were added to the solution. The reaction mixture was stirred at 80 °C for 48 h. After cooling, the solution was sonicated in DMF for 30 min, then centrifuged, and washed with ethanol for 3 times. The catalyst was then filtered and dried under vacuum at 60 °C to obtain the electron donor-acceptor conjugated polymer represented by formula (III), named as C13-alky-AQ. The polymer degree of polymerization was analyzed to be distributed in 1-100.

[0081] Example 3

[0082] A method for photocatalytic production of hydrogen peroxide, comprising the following steps:

[0083] 1 mg of the electron donor-acceptor conjugated polymer of Example 1 was ultrasonically dispersed in 50 mL of pure water for 30 min, stirred and irradiated with a xenon lamp to simulate sunlight, with a light power of 100 mW / cm 2 , to perform a test for photocatalytic production of hydrogen peroxide. After 1 h of testing, the hydrogen peroxide yield was 2549 μmol·g -1 ·h -1 .

[0084] Example 4

[0085] A method for photocatalytic production of hydrogen peroxide, comprising the following steps:

[0086] 1 mg of the electron donor-acceptor conjugated polymer of Example 2 was ultrasonically dispersed in 50 mL of pure water for 30 min, stirred and irradiated with a xenon lamp to simulate sunlight, with a light power of 100 mW / cm 2 , to perform a test for photocatalytic production of hydrogen peroxide. After 1 h of testing, the hydrogen peroxide yield was 2452 μmol·g -1 ·h -1 .

[0087] Comparative Example 1

[0088] An electron donor-acceptor conjugated polymer having the structure shown in formula (IV):

[0089] Formula (IV).

[0090] The preparation method of the above-mentioned electron donor-acceptor conjugated polymer includes the following steps:

[0091] 1,3-Diacetylenebenzene (100 mg) and 2,6-dibromoanthraquinone (290 mg) were dissolved in 8 mL of dimethylformamide (DMF) under an argon atmosphere. (PPh)₂PdCl₂ (55 mg), CuI₂ (7 mg), and triethylamine (8 mL) were added to the solution. The reaction mixture was stirred at 80 °C for 48 hours. After cooling, the mixture was sonicated in DMF for 30 minutes, then centrifuged and sonicated three times with ethanol. The catalyst was then filtered and dried under vacuum at 60 °C to obtain the electron donor-acceptor conjugated polymer shown in formula (IV), named Benz-alky-AQ.

[0092] 1 mg of the electron donor-acceptor conjugated polymer of formula (IV) was ultrasonically dispersed in 50 mL of pure water for 30 min. The mixture was stirred and then irradiated with a xenon lamp simulating sunlight at a power of 100 mW / cm². 2 The photocatalytic production of hydrogen peroxide was tested, and after 1 hour, the hydrogen peroxide yield was 1423 μmol·g. -1 ·h -1 .

[0093] Performance testing:

[0094] The electron donor-acceptor conjugated polymers of Example 1, Example 2, and Comparative Example 1 were tested using solid-state nuclear magnetic resonance spectroscopy, infrared spectroscopy, Raman spectroscopy, X-ray powder diffraction, scanning electron microscopy, and transmission electron microscopy, respectively. The test results are as follows:

[0095] Figure 1 The nuclear magnetic resonance (NMR) of the electron donor-acceptor conjugated polymers of Examples 1, 2, and Comparative Example 1 are shown. 13 C-NMR spectrum. Figure 1 (a) in the figure is the nuclear magnetic resonance (NMR) of the electron donor-acceptor conjugated polymer of Example 1. 13 C-NMR spectrum. Figure 1 (b) is the nuclear magnetic resonance (NMR) of the electron donor-acceptor conjugated polymer of Example 2. 13 C-NMR spectrum. Figure 1 (c) in the figure represents the nuclear magnetic resonance (NMR) of the electron donor-acceptor conjugated polymer of Example 1. 13 C-NMR spectrum.

[0096] Figure 2 These are diffuse reflectance infrared spectra of the electron donor-acceptor conjugated polymers of Examples 1, 2, and 1 Comparative Example.

[0097] Figure 3 These are the Raman spectra of the electron donor-acceptor conjugated polymers of Examples 1, 2, and 1 (Comparative Example 1).

[0098] Figure 4 These are XRD patterns of the electron donor-acceptor conjugated polymers of Examples 1, 2, and 1 (Comparative Example 1).

[0099] Figure 5 Scanning electron microscope (SEM) images show the electron donor-acceptor conjugated polymers of Examples 1, 2, and 1 (Comparative Example 1). Figure 5 (a) is a scanning electron microscope characterization of the electron donor-acceptor conjugated polymer of Example 1. Figure 5 (b) is a scanning electron microscope characterization of the electron donor-acceptor conjugated polymer of Example 2. Figure 5 (c) in the figure is a scanning electron microscope characterization of the electron donor-acceptor conjugated polymer of Comparative Example 1.

[0100] Figure 6 Transmission electron microscopy characterization images of the electron donor-acceptor conjugated polymers of Examples 1, 2 and Comparative Example 1. Figure 6 (a) is a transmission electron microscope characterization of the electron donor-acceptor conjugated polymer of Example 1. Figure 6 (b) is a transmission electron microscope characterization of the electron donor-acceptor conjugated polymer of Example 2. Figure 6 (c) in the figure is a transmission electron microscope characterization of the electron donor-acceptor conjugated polymer of Comparative Example 1.

[0101] The characteristic signal of the alkynyl group is derived from the solid state. 13 C nuclear magnetic resonance (C10) 13 The method was determined using C-NMR spectroscopy, Fourier transform infrared spectroscopy (FT-IR), and Raman spectroscopy. Specifically, 13 A signal of approximately 90 ppm in C-NMR ( Figure 1 ), ≈2210 cm⁻¹ in the FT-IR spectrum -1 The signal at the location ( Figure 2 ) and the 2200 cm in the Raman spectrum -1 The signal at the location ( Figure 3 The characteristic signal of the alkynyl group was determined. Furthermore, 13 The ketone carbon signal peak at approximately 180 ppm in the C NMR spectrum ( Figure 1 ), in the FT-IR spectrum at ~1670 cm⁻¹ -1 The stretching vibration signal peak at C=O (Figure 2 ), all of which provide important evidence for the determination of polymer structure. For PEG-alky-AQ, 13 The C-NMR spectrum corresponds to the carbon peaks of the oligoether chain modified by carbazole group at ≈71 ppm, ≈58 ppm and ≈44 ppm, while for C13-alky-AQ, 13 The C-NMR spectrum corresponds to the carbon peaks of the alkyl chain modified by carbazole group at ≈45 ppm, ≈30 ppm and ≈15 ppm, Figure 1 ), all of which prove the success of catalyst synthesis. Powder X-ray diffraction (PXRD) patterns ( Figure 4 ), scanning electron microscope (SEM) patterns ( Figure 5 ) and transmission electron microscope (TEM) patterns ( Figure 6 ) show that all the photocatalysts exhibit the layered characteristics of amorphous carbon. The successful polymerization of the electron donor-acceptor conjugated polymers of Example 1, Example 2 and Comparative Example 1 is determined by the above various analysis methods.

[0102] Figure 7 are the transient photocurrent response characterization diagrams of the electron donor-acceptor conjugated polymers of Example 1, Example 2 and Comparative Example 1 under argon atmosphere. Through the analysis of Figure 7 , it can be known that the amount of photo-generated carriers of the electron donor-acceptor conjugated polymers of Example 1 and Example 2 is significantly increased compared with Comparative Example 1.

[0103] In order to further explore the reason for the increase of photo-generated carriers, tests related to Figure 8 and Figure 9 are carried out. Figure 8 are the variable-temperature photoluminescence (PL) spectra of the electron donor-acceptor conjugated polymers of Example 1, Example 2 and Comparative Example 1. Figure 8 (a) in is the variable-temperature photoluminescence (PL) spectrum of the electron donor-acceptor conjugated polymer of Example 1. Figure 8 (b) in is the variable-temperature photoluminescence (PL) spectrum of the electron donor-acceptor conjugated polymer of Example 2. Figure 8 (c) in is the variable-temperature photoluminescence (PL) spectrum of the electron donor-acceptor conjugated polymer of Comparative Example 1.

[0104] In the temperature range of 200 K to 300 K, the PL intensity of the polymer gradually decreases with the increase of temperature. Further, the change rule of fluorescence intensity with temperature is fitted by using Arrhenius equation:

[0105]

[0106] where T is the thermodynamic temperature in Kelvin (K); I0is the fluorescence intensity at the initial temperature; I(T) represents the fluorescence intensity of the photocatalyst at temperature T; A is the pre-exponential factor; E a is the exciton binding energy; k B is the Boltzmann constant. A and E a were obtained by fitting the temperature-intensity plot.

[0107] Figure 9 is the plot of the temperature-dependent photoluminescence intensity of the electron donor-acceptor conjugated polymer of Example 1, Example 2 and Comparative Example 1 as a function of temperature. Figure 9 (a) in is the plot of the temperature-dependent photoluminescence intensity of the electron donor-acceptor conjugated polymer of Example 1 as a function of temperature. Figure 9 (b) in is the plot of the temperature-dependent photoluminescence intensity of the electron donor-acceptor conjugated polymer of Example 2 as a function of temperature. Figure 9 (c) in is the plot of the temperature-dependent photoluminescence intensity of the electron donor-acceptor conjugated polymer of Comparative Example 1 as a function of temperature. From Figure 9 It can be seen that the exciton binding energy (E a ) of the electron donor-acceptor conjugated polymer of Example 1 (PEG-alky-AQ) and Example 2 (C13-alky-AQ) are 74 meV and 52 meV, respectively, which are much smaller than that of the electron donor-acceptor conjugated polymer of Comparative Example 1 (Benz-alky-AQ) which is 184 meV. This result indicates that the electron donor-acceptor conjugated polymer of Example 1 (PEG-alky-AQ) and Example 2 (C13-alky-AQ) have lower exciton binding energy compared to the electron donor-acceptor conjugated polymer of Comparative Example 1 (Benz-alky-AQ), which facilitates the excitons to be more efficiently converted into photo-generated carriers.

[0108] It can be seen from Example 1 and Example 2 of the present application that the electron donor-acceptor conjugated polymer of Example 1 containing oligoether chain modified carbazole group as electron donor has higher hydrogen peroxide yield under the condition of pure water, open air, no sacrificial agent and simulated sunlight.

[0109] It can be seen from the above data that the electron donor-acceptor conjugated polymer of Example 1 (PEG-alky-AQ) and Example 2 (C13-alky-AQ) effectively reduce the exciton binding energy by introducing oligoether chain and alkyl chain to modify the carbazole group, respectively, compared to the electron donor-acceptor conjugated polymer of Comparative Example 1 (Benz-alky-AQ). The reduction of exciton binding energy facilitates more excitons to be dissociated into photo-generated carriers, thereby significantly improving the hydrogen peroxide yield.

[0110] Obviously, the above embodiments of the present application are merely exemplary but not intended to limit the embodiments of the present application. Based on the above description, any other variations or changes can be made by those skilled in the art without departing from the spirit and principles of the present application. It is not necessary to list all the embodiments here. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present application shall fall within the scope of the claims of the present application.

Claims

1. Use of an electron donor-acceptor conjugated polymer in reducing the exciton binding energy, characterized in that, The method for preparing the electron donor-acceptor conjugated polymer comprises the following steps: preparing with by polymerization reaction.

2. Use according to claim 1, characterized in that, Obtained by reaction of 1,3,6,8-tetrabromo-9H-carbazole with 1 -bromo-2-(2- methoxyethoxy)ethane.

3. Use of an electron donor-acceptor conjugated polymer in reducing the exciton binding energy, characterized in that, The method for preparing the electron donor-acceptor conjugated polymer comprises the following steps: mixing and obtained by polymerization reaction.

4. Use according to claim 3, characterized in that, Obtained by reaction of 1,3,6,8-tetrabromo-9H-carbazole and 1-bromotridecane.

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