An organic photoelectric compound based on a vinylcarbazole phosphonic acid structure, and a preparation method and application thereof

Abstract

The application belongs to the field of organic solar cell materials, and discloses an organic photoelectric compound based on a vinylcarbazole phosphonic acid structure and a preparation method and application thereof, the organic photoelectric compound has the following four structures: The organic photoelectric compound based on the vinylcarbazole phosphonic acid structure of the application forms firm chemical bonding with a metal oxide electrode (such as ITO or ZnO) through a phosphonic acid group, effectively passivates surface defects, and optimizes energy level alignment; meanwhile, the polymer main chain endows the material with excellent film-forming property and covering capacity, can form a uniform, dense and stable interface layer on the electrode, thereby significantly inhibiting charge recombination, improving carrier selective transmission efficiency, and enhancing the stability of the device in long-term operation and complex environment. The system provides an effective material solution for constructing an OPV device with high performance, high stability and suitable for large-area processing.

Description

Technical Field

[0001] This invention belongs to the field of organic solar cell materials, specifically relating to an organic photoelectric compound based on a vinylcarbazole phosphonic acid structure, its preparation method, and the application of this organic photoelectric compound as an interface material in optoelectronic devices. Background Technology

[0002] Organic photovoltaics (OPVs) have broad application prospects in portable energy, building-integrated photovoltaics, and wearable devices due to their advantages such as light weight, flexibility, semi-transparency, and suitability for large-area continuous fabrication using solution methods. In recent years, with the development of novel donor-acceptor materials, the photoelectric conversion efficiency of devices has been continuously improved. Charge-selective transport and recombination suppression at the electrode / active layer interface have gradually become key factors affecting device performance and stability.

[0003] Currently, the introduction of interface layers is crucial for optimizing energy level matching and improving carrier extraction. Besides small molecule interface materials, inorganic metal oxides (such as zinc oxide, ZnO) are also widely used as electron transport layers or interface modification layers. Although ZnO possesses high electron mobility and good optical transparency, its direct application has significant limitations: First, its surface often contains defect states (such as oxygen vacancies), which easily become charge recombination centers, leading to losses in open-circuit voltage and fill factor; second, the interfacial adhesion between ZnO and the organic active layer is poor, resulting in suboptimal energy level matching, and during solution processing, crystallinity or particle size distribution issues may affect film uniformity, limiting its application in OPV devices.

[0004] To overcome the aforementioned shortcomings, polymer interface materials have attracted attention due to their excellent film-forming properties and mechanical stability. They can form continuous, dense capping layers, effectively reducing interface defect density. However, existing polymer materials still have limitations in terms of chemical bonding strength with electrodes (such as ITO) and fine energy level control. Therefore, developing a polymer interface material that can simultaneously achieve strong interface anchoring, excellent film-forming properties, high carrier transport efficiency, and good stability has become an important direction in this field. Summary of the Invention

[0005] This invention addresses the problems of poor small molecule film-forming properties, insufficient interface stability, and weak polymer interface anchoring ability in existing organic solar cell interface materials. It provides a class of interface materials based on monomers and polymers of vinylcarbazole phosphonic acid, their preparation methods, and their applications in organic optoelectronic devices.

[0006] To achieve the above objectives, on the one hand, the present invention provides an organic photoelectric compound based on a vinylcarbazole phosphonic acid structure, having any one of the structures of formula (1) to (4):

[0007]

[0008] Equation (1);

[0009]

[0010] Equation (2);

[0011]

[0012] Equation (3);

[0013]

[0014] Equation (4).

[0015] As a further preferred technical solution of the present invention, the following steps are included:

[0016] Step S1: 3,6-Dibromo-9-vinylcarbazole and diethyl phosphonate undergo a CP coupling reaction under the catalysis of a catalyst to prepare an organic photoelectric compound with the structure of formula (1), wherein the catalyst is at least one of triethylamine, piperidine, pyridine, [1,1'-bis(diphenylphosphine)ferrocene]palladium dichloride, and triphenylphosphine palladium.

[0017] Step S2: The organic photoelectric compound with the structure of formula (1) is reacted with trimethylbromosilane to remove the alkoxy group, thereby obtaining the organic photoelectric compound with the structure of formula (2);

[0018] Step S3: The organic photoelectric compound with the structure of formula (1) undergoes free radical polymerization under azobisisobutyronitrile to obtain the organic photoelectric compound with the structure of formula (3);

[0019] Step S4: The organic photoelectric compound with the structure of formula (3) is reacted with trimethylbromosilane to remove the alkoxy group, thereby obtaining the organic photoelectric compound with the structure of formula (4).

[0020] As a further preferred technical solution of the present invention, step S1 specifically includes:

[0021] 3,6-dibromo-9-vinylcarbazole, diethyl phosphonate, solvent a and catalyst were added under inert gas protection and CP coupling reaction was carried out at room temperature or under reflux. The mixture was then extracted with dichloromethane, the organic phases were combined, dried with anhydrous sodium sulfate, the solvent was removed under reduced pressure, and the mixture was separated by column chromatography to obtain the organic photoelectric compound with the structure of formula (1).

[0022] Wherein, solvent a is at least one of chloroform, dichloromethane, and tetrahydrofuran; the ratio of solvent a to 3,6-dibromo-9-vinylcarbazole is 10-20 liters / mol.

[0023] As a further preferred technical solution of the present invention, step S2 specifically includes:

[0024] Under inert gas protection, the organic photoelectric compound of formula (1) was dissolved in solvent b at room temperature. Trimethylbromosilane was added dropwise to the solution under stirring. The resulting mixture was stirred at room temperature to carry out the dealkoxylation reaction. Then, methanol was slowly added to quench the excess trimethylbromosilane. The solvent was removed under reduced pressure. The crude product was purified by recrystallization to obtain the organic photoelectric compound of formula (2).

[0025] Wherein, solvent b is at least one of chloroform, dichloromethane, and 1,2-dichloroethane; the ratio of solvent b to the organic photoelectric compound of formula (1) is 10-20 liters / mol.

[0026] As a further preferred technical solution of the present invention, step S3 specifically includes:

[0027] Under inert gas protection, the organic photoelectric compound with the structure of formula (1) and azobisisobutyronitrile (AIBN) were mixed, solvent c was added and mixed evenly, and the reaction was stirred at room temperature or under heating. The mixture was then concentrated to dryness under reduced pressure using a rotary evaporator to obtain a brownish-yellow oily crude product. The crude product was purified by silica gel column chromatography with gradient elution using dichloromethane / methanol as the eluent to obtain a pale yellow solid, which is the organic photoelectric compound with the structure of formula (3).

[0028] Wherein, solvent c is one of o-dichlorobenzene, toluene, carbon tetrachloride, and methanol; the molar ratio of the organic photoelectric compound with the structure of formula (1) to azobisisobutyronitrile is 1: 0.01~0.1.

[0029] As a further preferred technical solution of the present invention, step S4 specifically includes:

[0030] Under inert gas protection, the organic photoelectric compound with the structure of formula (3) was dissolved in solvent d at room temperature. Trimethylbromosilane was added dropwise in batches while stirring, and the reaction was stirred at room temperature. Then, methanol was slowly added to quench the excess trimethylbromosilane. The solvent was removed under reduced pressure. The crude product was purified by recrystallization to obtain the organic photoelectric compound with the structure of formula (4).

[0031] Wherein, the solvent d is at least one of chloroform, dichloromethane, and 1,2-dichloroethane; the ratio of solvent d to the organic photoelectric compound of formula (3) is 10-20 liters / mol.

[0032] According to a second aspect of the present invention, the present invention also provides an application of the organic optoelectronic compounds of the above formulas (1)-(4) as interface modification materials in modifying the electron transport layer in optoelectronic devices.

[0033] According to a second aspect of the present invention, the present invention also provides an organic solar cell comprising, in sequence, a conductive glass, an electron transport layer, a modification layer, an active layer, a hole transport layer and a metal electrode, wherein the modification layer is deposited from an organic photoelectric compound of formulas (1)-(4) above.

[0034] As a further preferred embodiment of the present invention, the conductive glass is indium tin oxide glass, the electron transport layer is zinc oxide, the active layer is a bulk heterojunction (BHJ) active layer composed of a polymer donor (PM6) and a small molecule acceptor (CH-B), the hole transport layer is molybdenum trioxide, and the metal electrode is gold or silver.

[0035] This invention designs an organic optoelectronic compound based on a vinylcarbazole phosphonic acid structure as an interface material. Through the formation of strong chemical bonds between the phosphonic acid groups and metal oxide electrodes (such as ITO or ZnO), it effectively passivates surface defects and optimizes energy level alignment. Simultaneously, the polymer backbone endows the material with excellent film-forming properties and covering ability, enabling the formation of a uniform, dense, and stable interface layer on the electrode. This significantly suppresses charge recombination, improves carrier selective transport efficiency, and enhances the stability of the device under long-term operation and complex environments. This system provides an effective material solution for constructing high-performance, high-stability OPV devices suitable for large-area fabrication.

[0036] Compared with the prior art, the present invention can achieve the following beneficial effects:

[0037] The organic optoelectronic materials of this invention have simple synthesis steps, are easy to purify, and have a well-defined structure. Compared with traditional ZnO interface layers, organic photovoltaic devices prepared using the organic optoelectronic materials of this invention as interface modification materials exhibit superior photovoltaic performance, with a photoelectric conversion efficiency of up to 18.58%. Attached Figure Description

[0038] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0039] Figure 1 The diagram shows the synthesis circuits of the organic photoelectric compounds in Examples 1 and 2.

[0040] Figure 2 The diagram shows the synthesis circuits of the organic photoelectric compounds in Examples 3 and 4.

[0041] Figure 3 The current-voltage curves are those of organic photovoltaic devices prepared using the organic optoelectronic compounds of Examples 2 and 4 as interface modification layers.

[0042] The objectives, features, and advantages of this invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0043] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0044] Unless otherwise defined, the technical terms used in the following embodiments have the same meanings as commonly understood by those skilled in the art to which this invention pertains. Unless otherwise specified, the experimental reagents used in the following embodiments are conventional biochemical reagents; and the experimental methods described are conventional methods.

[0045] Examples 1-4 below are examples of the synthesis of organic photoelectric compounds.

[0046] Example 1

[0047] like Figure 1 The synthetic route of the organic optoelectronic compound provided in this embodiment is as follows:

[0048] To a 100 mL two-necked round-bottom flask, add 1.40 g of 3,6-dibromo-9-vinylcarbazole, 2.21 g of diethyl phosphonite (16.0 mmol), and 0.8 mmol of [1,1'-bis(diphenylphosphine)ferrocene]palladium dichloride (Pd(dppf)Cl2, 585 mg). Purify the reaction mixture with argon using a double-row tube system (repeated three times). Under argon protection, add 30 mL of anhydrous tetrahydrofuran (THF), followed by 2.78 mL (20.0 mmol) of anhydrous triethylamine, and stir until homogeneous. Place the flask in an oil bath and heat to 68°C, stirring magnetically for 12 h. During the reaction, take a small sample of the reaction mixture and monitor the progress using thin-layer chromatography. Once the reactants are confirmed to be completely consumed, stop heating and allow the reaction mixture to cool naturally to room temperature. Under stirring, the cooled reaction solution was slowly poured into 100 mL of saturated ammonium chloride aqueous solution for quenching, followed by extraction with dichloromethane three times, 50 mL each time. All organic phases were combined, dried with an appropriate amount of anhydrous sodium sulfate, filtered to remove the desiccant, and the filtrate was collected. The filtrate was concentrated to dryness under reduced pressure using a rotary evaporator to obtain a brownish-yellow oily crude product. The crude product was purified by silica gel column chromatography (silica gel particle size 200-300 mesh) using a gradient elution with petroleum ether / ethyl acetate (volume ratio 10:1-3:1). The target fraction was collected, concentrated under reduced pressure to obtain target compound 1 (as shown in Formula 1 below), a pale yellow solid totaling 1.34 g, with a yield of 72%.

[0049]

[0050] Equation (1)

[0051] The structure of compound 1 was characterized as follows:

[0052] 1 H NMR (400 MHz, CDCl3) δ: 8.61 (dd, J = 13.7, 1.4 Hz, 2H), 7.95 (ddd,J = 12.4, 8.5, 1.5 Hz, 2H), 7.72 (dd, J = 8.5, 3.0 Hz, 2H), 7.24 (d, J = 15.8Hz, 1H), 5.66 (dd, J = 15.9, 1.2 Hz, 1H), 5.41 (dd, J = 8.9, 1.2 Hz, 1H), 4.25 – 4.08 (m, 8H), 1.35 (t, J = 7.1 Hz, 12H).

[0053] 13 C NMR (101 MHz, CDCl3) δ: 140.97, 140.94, 129.17, 129.05, 127.74,124.26, 124.15, 122.35, 122.18, 120.33, 118.42, 109.79, 109.63, 105.99,61.13, 61.08, 15.41, 15.35.

[0054] 31 P NMR (162 MHz, CDCl3) δ: 19.92.

[0055] HRMS Calcd for C 22 H 29 NNaO6P2 + (M+Na) + Found: 488.1362;

[0056] Example 2

[0057] like Figure 1 The synthetic route of the organic optoelectronic compound provided in this embodiment is as follows:

[0058] Under a nitrogen atmosphere, compound 1 (Formula 1) (930 mg, 2.0 mmol) was dissolved in anhydrous dichloromethane (30 mL) at room temperature. Trimethylbromosilane (2.64 mL, 20.0 mmol) was added dropwise to the stirred solution over 5 minutes. The resulting mixture was stirred at room temperature for 12 hours, and the reaction progress was monitored by thin-layer chromatography. After confirming that the starting material was completely consumed, excess trimethylbromosilane was quenched by slowly adding methanol (10 mL), and the solvent was removed under reduced pressure. The crude product was purified by recrystallization from methanol / methyl tert-butyl ether (volume ratio = 1:4) to obtain the target phosphonic acid compound 2 (Formula 2 below, denoted as VK-PA), a white solid, totaling 566 mg, in yield of 80%.

[0059]

[0060] Equation (2)

[0061] The structure of compound 2 was characterized as follows:

[0062] 1 H NMR (400 MHz, DMSO-d6) δ: 9.05 (s, 3 h), 8.42 (d, J = 13.7 Hz, 1H), 7.83 (s, 1H), 7.69 (d, J = 13.5 Hz, 1H), 7.55 (s, 1H), 7.32 (t, J = 55.0 Hz,2H), 1.05 (d, J = 3.1 Hz, 2H).

[0063] 31 P NMR (162 MHz, DMSO) δ: 14.97.

[0064] HRMS Calcd for C 14 H 13 LiNO6P2 + (M+Li) + Found: 360.0373; Found: 360.3238.

[0065] Example 3

[0066] like Figure 2 The synthetic route of the organic optoelectronic compound provided in this embodiment is as follows:

[0067] Compound 1 (Formula 1) (930 mg, 2.0 mmol) and azobisisobutyronitrile (AIBN, 16.2 mg, 0.1 mmol) were added sequentially to a 10 mL Schlenk tube. The reaction mixture was purged with argon using a double-row tube system (repeated three times). Under argon protection, 1.0 mL of anhydrous carbon tetrachloride was added, and the mixture was stirred until homogeneous. The reaction flask was placed in an oil bath and heated to 80°C with magnetic stirring for 24 h. During the reaction, a small amount of the reaction solution was taken and the reaction progress was monitored by thin-layer chromatography. Once the starting material was confirmed to have ceased conversion, heating was stopped, and the reaction mixture was allowed to cool naturally to room temperature. The solution was concentrated to dryness using a rotary evaporator under reduced pressure to obtain a brownish-yellow oily crude product. The crude product was purified by silica gel column chromatography (silica gel particle size 200-300 mesh), and gradient elution was performed using dichloromethane / methanol (volume ratio 20:1-10:1). The target component was collected and concentrated under reduced pressure to obtain target compound 3 (as shown in Formula 3 below), a total of 428 mg of pale yellow solid, with a yield of 46%.

[0068]

[0069] Equation (3)

[0070] The structure of compound 3 was characterized as follows:

[0071] 1 H NMR (400 MHz, CDCl3) δ: 8.54 (dd, J = 13.7, 4.9 Hz, 2H), 7.77 (dd,J = 12.5, 8.3 Hz, 2H), 7.57–7.46 (m, 2H), 4.13–4.01 (m, 11H), 1.26 (q, J =7.1, 5.9 Hz, 16H).

[0072] 13 C NMR (101 MHz, CDCl3) δ: 142.09, 142.07, 128.28, 128.16, 124.38, 124.28, 124.17, 124.05, 121.33, 117.56, 115.64, 110.73, 110.57, 61.30, 61.26,61.22, 61.20, 61.17, 61.08, 61.03, 15.44, 15.39, 15.37, 15.33.

[0073] 31 P NMR (162 MHz, CDCl3) δ: 21.34, 20.20, 19.58.

[0074] n=2, HRMS Calcd for C 44 H 60 LiN2O 12 P4 + (M+Li) + Found: 939.3251; Found: 939.4834.

[0075] n=3, HRMS Calcd for C 66 H 89 LiN3O 18 P6 + (M+Li) + : 1405.2230; Found:1405.5492.

[0076] Example 4

[0077] like Figure 2 The synthetic route of the organic optoelectronic compound provided in this embodiment is as follows:

[0078] Under a nitrogen atmosphere, compound 3 (Formula 3) (233 mg, 0.5 mmol) was dissolved in anhydrous dichloromethane (10 mL) at room temperature. Trimethylbromosilane (0.6 mL, 5.0 mmol) was added dropwise to the stirred solution over 2 minutes. The resulting mixture was stirred at room temperature for 12 hours, and the reaction progress was monitored by thin-layer chromatography. After confirming that the starting material was completely consumed, excess trimethylbromosilane was quenched by slowly adding methanol (5 mL), and the solvent was removed under reduced pressure. The crude product was purified by recrystallization from methanol / methyl tert-butyl ether (volume ratio = 1:4) to obtain the target phosphonic acid compound 4 (Formula 4 below, denoted as PVK-PA), a white solid, totaling 110 mg, with a yield of 62%.

[0079]

[0080] Equation (4)

[0081] The structure of compound 4 was characterized as follows:

[0082] 1 H NMR (400 MHz, DMSO-d6) δ: 8.45 (d, J = 13.7 Hz, 2H), 7.74 (t, J =10.4 Hz, 2H), 7.58 (d, J = 8.5 Hz, 2H), 1.22 (s, 2H), 1.10 (s, 3H).

[0083] 13 C NMR (101 MHz, DMSO) δ: 141.93, 128.93, 125.38, 123.67, 111.51,31.77, 2.49, 2.29.

[0084] 31 P NMR (162 MHz, DMSO) δ: 15.83, 14.82, 14.40.

[0085] Based on the compounds 1, 2, 3 and 4 prepared above, the following are application examples of the organic optoelectronic compounds as described in Examples 5-8.

[0086] Comparative Example 1

[0087] This comparative example provides a conventional solar cell device without interface modification, which adopts a Glass / ITO / ETL / PM6:CH-B / MoO3 / Ag structure, and the specific fabrication method is as follows:

[0088] 1) Substrate cleaning: The indium tin oxide (ITO) glass substrate was sequentially immersed in a detergent solution, deionized water, acetone, and isopropanol, and cleaned in an ultrasonic bath for 15 minutes in each solution, then dried with nitrogen. Before use, the cleaned ITO substrate was subjected to UV exposure treatment for 15 minutes in a UV ozone chamber (Jelite Corporation).

[0089] 2) Deposition of the electron transport layer: The prepared ZnO solution was first spin-coated onto the ITO glass substrate at a speed of 3000 rpm for 20 seconds, followed by heat annealing in air at 200°C for 60 minutes. Afterward, the substrate was transferred to a glove box filled with nitrogen.

[0090] 3) Deposition of the active layer: PM6:CH-B (donor to acceptor ratio of 1:1.2) was completely dissolved in chloroform (CF) at a donor concentration of 7.0 mg / mL. 50% by weight of the solid additive 2,5-dichlorothiophene[3,2-b]thiophene (TT-Cl) was added, and the mixture was spin-coated onto the electron transport layer (ETL) at 2000 rpm for 30 seconds. After spin-coating, the mixed film was annealed at 90°C for 5 minutes. The optimal active layer thickness was approximately 100 nm.

[0091] 4) Deposition of hole transport layer and electrodes: at 2×10 -6 A 2.7 nm thick MoO3 layer and a 150 nm thick silver electrode were deposited under vacuum conditions. The active area of ​​the device is 4 mm², and a 3.24 mm² mask was used for current-voltage (JV) testing.

[0092] Example 5

[0093] This embodiment provides a solar cell prepared by modifying ZnO with compound 1 as an interface modification material. The only difference between the preparation method and Comparative Example 1 is that a modification layer is deposited on the electron transport layer (ETL) before depositing the active layer. All other steps are the same as those in Comparative Example 1.

[0094] In this embodiment, the deposition method of the modified layer is as follows: Compound 1 is dissolved in methanol at 0.3 mg / mL, filtered through a 0.22-micron filter, and then spin-coated at 5000 rpm for 20 seconds onto the electron transport layer (ETL). After spin-coating, it is heat-annealed at 100°C for 5 minutes.

[0095] Example 6

[0096] The only difference from Example 5 is that compound 1 is replaced with compound 2 (VK-PA).

[0097] Example 7

[0098] The only difference from Example 5 is that compound 1 is replaced by compound 3.

[0099] Example 8

[0100] The only difference from Example 5 is that compound 1 is replaced with compound 4 (PVK-PA).

[0101] Comparative Example 2

[0102] The only difference from Example 5 is that compound 1 is replaced with polymer PVK, the structure of which is as follows:

[0103] .

[0104] Comparative Example 3

[0105] The only difference from Example 5 is that compound 1 is replaced by compound 2PACz, the structure of which is as follows:

[0106] .

[0107] The relevant photoelectric parameters of the devices prepared in Comparative Examples 1-3 and Examples 5-8 are obtained and summarized in Table 1.

[0108] Table 1

[0109]

[0110] As shown in Table 1, the solar cells prepared by modifying ZnO with organic photoelectric compounds 1-4 as interface modifiers all achieve high power conversion efficiencies, significantly better than those of comparative examples 1-3. The comprehensive comparison demonstrates the effectiveness of the vinylcarbazole phosphonic acid compounds as interface materials, with compound 4 (PVK-PA) showing the best performance, enabling organic solar cell devices to achieve a photoelectric conversion efficiency as high as 18.58%. Benefiting from their well-defined molecular structure and simple preparation process, these materials show promising application prospects in flexible, large-area fabrication of high-performance and highly stable organic solar cells.

[0111] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and various changes or modifications can be made to these embodiments without departing from the principles and essence of the present invention. The scope of protection of the present invention is defined only by the appended claims.

Claims

1. An organic photoelectric compound based on a vinylcarbazole phosphonic acid structure, characterized in that, It has any one of the structures of equations (1) to (4): ； Equation (1) ； Equation (2) ； Equation (3) ； Equation (4).

2. The method for preparing the organic photoelectric compound according to claim 1, characterized in that, Includes the following steps: Step S1: 3,6-Dibromo-9-vinylcarbazole and diethyl phosphonate undergo a CP coupling reaction under the catalysis of a catalyst to prepare an organic photoelectric compound with the structure of formula (1), wherein the catalyst is at least one of triethylamine, piperidine, pyridine, [1,1'-bis(diphenylphosphine)ferrocene]palladium dichloride, and triphenylphosphine palladium. Step S2: The organic photoelectric compound with the structure of formula (1) is reacted with trimethylbromosilane to remove the alkoxy group, thereby obtaining the organic photoelectric compound with the structure of formula (2); Step S3: The organic photoelectric compound with the structure of formula (1) undergoes free radical polymerization under azobisisobutyronitrile to obtain the organic photoelectric compound with the structure of formula (3); Step S4: The organic photoelectric compound with the structure of formula (3) is reacted with trimethylbromosilane to remove the alkoxy group, thereby obtaining the organic photoelectric compound with the structure of formula (4).

3. The preparation method according to claim 2, characterized in that, Step S1 specifically includes: 3,6-dibromo-9-vinylcarbazole, diethyl phosphonate, solvent a and catalyst were added under inert gas protection and CP coupling reaction was carried out at room temperature or under reflux. The mixture was then extracted with dichloromethane, the organic phases were combined, dried with anhydrous sodium sulfate, the solvent was removed under reduced pressure, and the mixture was separated by column chromatography to obtain the organic photoelectric compound with the structure of formula (1). Wherein, solvent a is at least one of chloroform, dichloromethane, and tetrahydrofuran; the ratio of solvent a to 3,6-dibromo-9-vinylcarbazole is 10-20 liters / mol.

4. The preparation method according to claim 2, characterized in that, Step S2 specifically includes: Under inert gas protection, the organic photoelectric compound of formula (1) was dissolved in solvent b at room temperature. Trimethylbromosilane was added dropwise to the solution under stirring. The resulting mixture was stirred at room temperature to carry out the dealkoxylation reaction. Then, methanol was slowly added to quench the excess trimethylbromosilane. The solvent was removed under reduced pressure. The crude product was purified by recrystallization to obtain the organic photoelectric compound of formula (2). Wherein, solvent b is at least one of chloroform, dichloromethane, and 1,2-dichloroethane; the ratio of solvent b to the organic photoelectric compound of formula (1) is 10-20 liters / mol.

5. The preparation method according to claim 2, characterized in that, Step S3 specifically includes: Under inert gas protection, the organic photoelectric compound with the structure of formula (1) and azobisisobutyronitrile (AIBN) were mixed, solvent c was added and mixed evenly, and the reaction was stirred at room temperature or under heating. The mixture was then concentrated to dryness under reduced pressure using a rotary evaporator to obtain a brownish-yellow oily crude product. The crude product was purified by silica gel column chromatography with gradient elution using dichloromethane / methanol as the eluent to obtain a pale yellow solid, which is the organic photoelectric compound with the structure of formula (3). Wherein, solvent c is one of o-dichlorobenzene, toluene, carbon tetrachloride, and methanol; the molar ratio of the organic photoelectric compound with the structure of formula (1) to azobisisobutyronitrile is 1: 0.01~0.

1.

6. The preparation method according to claim 2, characterized in that, Step S4 specifically includes: Under inert gas protection, the organic photoelectric compound with the structure of formula (3) was dissolved in solvent d at room temperature. Trimethylbromosilane was added dropwise in batches while stirring, and the reaction was stirred at room temperature. Then, methanol was slowly added to quench the excess trimethylbromosilane. The solvent was removed under reduced pressure. The crude product was purified by recrystallization to obtain the organic photoelectric compound with the structure of formula (4). Wherein, the solvent d is at least one of chloroform, dichloromethane, and 1,2-dichloroethane; the ratio of solvent d to the organic photoelectric compound of formula (3) is 10-20 liters / mol.

7. The application of the organic optoelectronic compound of claim 1 as an interface modification material in modifying the electron transport layer in optoelectronic devices.

8. An organic solar cell, characterized in that, It includes a conductive glass, an electron transport layer, a modification layer, an active layer, a hole transport layer, and a metal electrode arranged sequentially, wherein the modification layer is deposited from the organic optoelectronic compound of claim 1.

9. The solar cell according to claim 8, characterized in that, The conductive glass is indium tin oxide glass, the electron transport layer is zinc oxide, the active layer is a bulk heterojunction (BHJ) active layer composed of a polymer donor (PM6) and a small molecule acceptor (CH-B), the hole transport layer is molybdenum trioxide, and the metal electrode is gold or silver.

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