Fused ring electron acceptor material containing imine bond as well as preparation and application of fused ring electron acceptor material
By designing fused-ring electron acceptor materials containing imine bonds and employing specific synthetic routes and solvent systems, the stability problem caused by the enlargement of the conjugated backbone was solved, achieving near-infrared absorption and efficient photoelectric conversion.
Patent Information
- Application Number
- CN202511804671.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-03
- Publication Date
- 2026-03-06
AI Technical Summary
In existing technologies, the introduction of π-bridges to increase the conjugation length of the conjugated framework results in high material synthesis costs and insufficient structural stability, making it difficult to achieve narrow bandgap electron acceptor materials with near-infrared absorption.
Using fused-ring electron acceptor materials containing imine bonds, and with an octa-aryl fused heterocyclic unit and a chalcogenide as the central core, and introducing an electron-withdrawing EG end unit, combined with specific solvents and catalysts, a highly efficient synthesis was achieved through silanization, nitrosation, and Knoevenagel condensation reactions.
The light absorption range of the material was extended to the near-infrared region, improving structural stability and photoelectric performance, and achieving a photoelectric conversion efficiency of over 16%.
Smart Images
Figure CN121609710A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of fused-ring electron acceptor materials, specifically to a fused-ring electron acceptor material containing imine bonds, its preparation, and its application. Background Technology
[0002] Organic semiconductor materials containing trapezoidal fused rings have attracted widespread attention due to their excellent performance in electronic devices such as organic field-effect transistors (OFETs), organic solar cells (OSCs), and photodetectors (OPDs). One of the focal points in the design of organic semiconductor acceptor materials is how to modify the molecular structure to change the energy level structure, light absorption properties, and intermolecular interactions to achieve a wider spectral response range and higher carrier mobility. Currently, strategies have been proposed to broaden the light absorption range of acceptor materials by controlling the molecular structure to change the optical band gap, such as widening the π-conjugated backbone length, side-chain engineering, fused ring core engineering, and end-group engineering. Among these strategies, the modification and adjustment of the electron cloud distribution of the donor and acceptor units in trapezoidal fused ring acceptor materials has been widely used to modulate the photoelectric properties of organic semiconductor materials.
[0003] However, obtaining narrow bandgap electron acceptor materials with cutoff absorption wavelengths greater than 1000 nm typically requires introducing ethylene or heterocyclic units as π-bridges between the donor and acceptor units to extend the π-conjugated backbone of the main chain. The introduction of π-bridges leads to an increase in exocyclic σ-bonds in the main chain, resulting in increased molecular recombination energy and poor structural stability. Therefore, constructing near-infrared absorption electron acceptors that satisfy specific photoelectric properties and are easily synthesized is crucial. Summary of the Invention
[0004] The purpose of this invention is to provide a fused-ring electron acceptor material containing imine bonds, its preparation and application, to solve the problems of the existing technology that introduce π-bridges to increase the conjugation length of the conjugated skeleton to achieve near-infrared absorption in the absorption range of the material, resulting in high synthesis costs, and the increase in the number of freely rotating chemical bonds in the conjugated skeleton, which increases the recombination energy of the molecule and leads to insufficient structural stability of the molecule.
[0005] To achieve the above objectives, the present invention provides the following technical solution: a fused-ring electron acceptor material containing imine bonds, comprising a narrow bandgap electron acceptor material containing imine bonds, the general molecular structure of which is shown in the following formula:
[0006]
[0007] The central core is an octa-aroma fused heterocyclic unit;
[0008] X1 is selected from the oxalic group elements, including oxygen, sulfur and selenium atoms;
[0009] R1 and R2 are each independently selected from: C1-C26 alkyl, C1-C24 alkoxy, C1-C24 alkylthio, and C1-C26 partially fluorinated alkyl;
[0010] The EG unit is an electron-deficient functional group or a substituent unit with electron-withdrawing ability, selected from any of the following groups:
[0011]
[0012] R3 can be a hydrogen atom, halogen, hydroxyl group, nitro group, cyano group, ester group (such as C1-C20 alkoxy acyl group), carbonyl group, C1-C20 alkyl group, or C1-C20 alkoxy group.
[0013] The preparation of a fused-ring electron acceptor material containing imine bonds includes the following steps:
[0014] S1. The conditions for the silanization reaction are as follows: the solvent is tetrahydrofuran, n-butyllithium is used as a strong base, the molar ratio of compound A to the strong base is 1:2 to 1:4, and the reaction is carried out at -78 to -70°C for 1 to 2 hours; then trimethylchlorosilane (TMSCl) is added as a reactant, the molar ratio of substrate to reactant is 1:3 to 1:4, and the reaction is carried out at 0 to 30°C for 5 to 10 hours.
[0015]
[0016] S2: The conditions for the nitrosation reaction are as follows: the solvent is a polar organic solvent, nitrosium tetrafluoroborate is the nitrosating agent, the molar ratio of compound B to the nitrosating agent is 1:2 to 1:4, and the reaction is carried out at 0 to 30°C for 1 to 3 hours to obtain compound C.
[0017]
[0018] Among them, polar organic solvents include, but are not limited to, dimethyl sulfoxide, N,N'-dimethylformamide, N-methylpyrrolidone, acetonitrile, chlorobenzene, and chloroform;
[0019]
[0020] The reaction conditions for S3: Knoevenagel condensation reaction are as follows: the solvent is an aromatic solvent, the catalyst is an acid anhydride and a boron trifluoride diethyl ether complex, with a molar ratio of 1:0.1 to 1:1.5, and the molar ratio of compound C to the EG type end group is 1:3 to 1:4. The reaction is carried out at 0 to 50 °C for 30 to 60 minutes to obtain a compound with the structure shown in Formula 1. The aromatic solvent includes, but is not limited to, toluene, xylene, trimethylbenzene, chlorobenzene, and dichlorobenzene, and the acid anhydride includes, but is not limited to, acetic anhydride, propionic anhydride, valeric anhydride, succinic anhydride, maleic anhydride, and glutaric anhydride.
[0021] Application of an imine-bonded electron acceptor material in the fabrication of optoelectronic functional devices.
[0022] Furthermore, the optoelectronic functional devices include organic photovoltaic cells, photodetectors, organic field-effect devices, and organic light-emitting semiconductor devices.
[0023] Compared with the prior art, the present invention provides a fused ring electron acceptor material containing imine bonds, its preparation and application. By setting the polar imine bonds as π-bridges to connect the electron-donating and electron-withdrawing units, the optical band gap of the molecule is effectively reduced, and the absorption range of the material is extended to around 1000 nm. At the same time, due to the simple molecular structure and fewer freely rotating single bonds in the conjugated backbone, the structural stability and photoelectric performance reliability of the material are improved.
[0024] By employing an octa-aroma fused heterocyclic unit as the central core and combining it with optional oxalic elements (O, S, Se) as X1 substituents, the planarity and conjugation of the molecule are enhanced, and the electron cloud distribution is optimized, thereby achieving a wider absorption spectrum and higher carrier mobility.
[0025] By introducing EG end units with electron-withdrawing capabilities and combining them with the diverse selection of R3 substituents (such as halogen, cyano, ester, etc.), the energy level structure and light absorption properties of the molecule were further adjusted, enhancing the electron affinity and solubility of the material, thereby broadening its absorption range in the near-infrared region and improving the device fabrication adaptability.
[0026] By adopting a three-step synthetic route (silanization, nitrosation, and Knoevenagel condensation) and combining specific solvents, catalysts, and reaction conditions, an efficient and controllable synthetic process was achieved, improving the purity and yield of the target product. This provides a feasible route for the large-scale preparation of high-quality fused-ring electron acceptor materials.
[0027] By applying the electron acceptor material to optoelectronic functional devices such as organic photovoltaic cells and photodetectors, its excellent performance in terms of wide spectral response, high short-circuit current density, and high open-circuit voltage has been demonstrated, thereby achieving a photoelectric conversion efficiency of over 16% and promoting the development of near-infrared optoelectronic devices. Attached Figure Description
[0028] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.
[0029] Figure 1The receptor material prepared in Example 1 of this invention 1 H NMR spectrum;
[0030] Figure 2 The receptor material prepared in Example 2 of this invention 1 H NMR spectrum;
[0031] Figure 3 The ultraviolet-visible absorption spectra of the thin films of compounds 1 and 2 provided in the embodiments of the present invention. Detailed Implementation
[0032] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.
[0033] As attached Figure 1 To be continued Figure 3 As shown:
[0034] The anhydrous tetrahydrofuran and anhydrous acetonitrile used in the following examples were purchased from Anhui Zesheng Technology Co., Ltd.; toluene, dichloromethane, petroleum ether, acetic anhydride, n-butyllithium, trimethylchlorosilane, nitrosium tetrafluoroborate, and methanol were purchased from Shanghai Titan Technology Co., Ltd.; and 3-(dicyanomethylene)indoketone was purchased from Suzhou Nakai Technology Co., Ltd.
[0035] The materials were tested using a Bruker AVANCE-400 nuclear magnetic resonance spectrometer. 1 HNMR spectrum.
[0036] Example 1:
[0037] This invention provides a fused-ring electron acceptor material containing an imine bond, its preparation and application, wherein R1 is... R2 is X1 is a sulfur atom, EG is The preparation method of the electron acceptor material is as follows:
[0038] (1) Compound 6 and trimethylchlorosilane were reacted with n-butyllithium to give compound 7, wherein compound 6 was synthesized according to the reference (Adv. Mater. 2020, 32, 1908205.):
[0039]
[0040] Synthesis of Compound 7: In a dry 100 mL round-bottom double-necked flask, weigh out Compound 6 (0.51 g, 0.50 mmol) and anhydrous tetrahydrofuran (40 mL). Cool to -78 °C, add n-butyllithium (2.5 M, 0.8 mL, 2.0 mmol) under nitrogen protection, and stir at -70 °C for 1 hour. Add trimethylchlorosilane (0.22 g, 2.0 mmol), and continue stirring until room temperature. React overnight. Extract with dichloromethane, remove the solvent using a rotary evaporator, and purify by silica gel column chromatography using dichloromethane and petroleum ether as eluents to obtain a pale yellow solid (0.54 g, 0.46 mmol), which is Compound 7.
[0041] (2) Compound 7 and nitrosium tetrafluoroborate undergo a nitrosation reaction to give compound 8:
[0042]
[0043] Synthesis of Compound 8: Compound 7 (0.47 g, 0.40 mmol) and anhydrous acetonitrile (30 mL) were weighed into a dry 50 mL round-bottom double-necked flask. Nitrosium tetrafluoroborate (0.19 g, 1.60 mmol) was added under nitrogen protection, and the mixture was stirred at room temperature for 2 hours. The reaction was quenched by adding water, extracted with dichloromethane, and the solvent was removed by rotary evaporation. The mixture was purified by silica gel column chromatography using dichloromethane and petroleum ether as eluents to give a light green solid (0.41 g, 0.38 mmol), which was Compound 8.
[0044] (3) Compound 8 and 5,6-difluoro-3-(dicyanomethylene)indone (IC-2F) undergo a Knoevenagel condensation reaction to give target product 1:
[0045]
[0046] Synthesis of Compound 1: In a dry 50 mL round-bottom double-necked flask, 0.16 g (0.15 mmol) of Compound 8 and 0.087 g (0.38 mmol) were weighed and dissolved in 10 mL of toluene. Under nitrogen protection, 0.2 mL of acetic anhydride and 0.1 mL of boron trifluoride diethyl ether were added, and the mixture was stirred at room temperature for 30 minutes. The solvent was removed by rotary evaporation. The product was purified by silica gel column chromatography using dichloromethane and petroleum ether as eluents. The purified product was washed with methanol to obtain the target product 1, a black solid (0.20 g, 0.13 mmol). The 1H NMR spectrum of Compound 1 is as follows: 1¹H NMR (400MHz, Chloroform-d) δ 8.51 (dd, J=10.0, 6.4Hz, 2H), 7.68 (t, J=7.4Hz, 2H), 4.76 (d, J=6.4Hz, 4H), 3.23 (m, 4H), 2.07 (p, J=6.4Hz, 2H), 1.92 (m, 4H), 1.75–1.53 (m, 10H), 1.42 (d, J=8.4Hz, 12H), 1.37–0.78 (m, 34H), 0.77 (td, J=7.0, 2.8Hz, 12H), 0.67 (td, J=7.0, 4.2Hz, 6H). The mass spectrometry data for compound 1 are: MALDI-HRMS m / z: calcd for C 84 H 92 F4N 10 O2S5 [M+]: 1508.5944; found: 1508.5965.
[0047] Example 2:
[0048] This embodiment is basically the same as the previous embodiment, except that R1 is R2 is X1 is a sulfur atom, EG is The preparation method of the electron acceptor material is as follows:
[0049] (1) Compound 3 and trimethylchlorosilane were reacted with n-butyllithium to give compound 4, wherein compound 3 was synthesized according to the reference (Nat.Sci.Rev.,2020,7(7):1239–1246.):
[0050]
[0051] Synthesis of Compound 4: In a dry 100 mL round-bottom double-necked flask, 0.44 g (0.40 mmol) of Compound 6 and 40 mL of anhydrous tetrahydrofuran were weighed. The mixture was cooled to -78 °C, and under nitrogen protection, 0.6 mL (2.5 M, 1.6 mmol) of n-butyllithium was added. The mixture was stirred at -70 °C for 1 hour. Trimethylchlorosilane (0.18 g, 1.6 mmol) was added, and the mixture was stirred until room temperature was reached. The reaction was allowed to proceed overnight. The mixture was extracted with dichloromethane, and the solvent was removed by rotary evaporation. Using dichloromethane and petroleum ether as eluents, the mixture was purified by silica gel column chromatography to obtain a pale yellow solid (0.43 g, 0.35 mmol), which was Compound 4.
[0052] (2) Compound 4 and nitrosium tetrafluoroborate undergo a nitrosation reaction to give compound 5:
[0053]
[0054] Synthesis of Compound 5: Compound 4 (0.39 g, 0.31 mmol) and anhydrous acetonitrile (25 mL) were weighed into a dry 50 mL round-bottom double-necked flask. Nitrosium tetrafluoroborate (0.14 g, 1.20 mmol) was added under nitrogen protection, and the mixture was stirred at room temperature for 2 hours. The reaction was quenched by adding water, extracted with dichloromethane, and the solvent was removed by rotary evaporation. The mixture was purified by silica gel column chromatography using dichloromethane and petroleum ether as eluents to give a light green solid (0.31 g, 0.27 mmol), which was compound 5.
[0055] (3) Compound 5 and 5,6-difluoro-3-(dicyanomethylene)indone (IC-Cl-delta) undergo a Knoevenagel condensation reaction to give target product 2:
[0056]
[0057] Synthesis of Compound 2: In a dry 50 mL round-bottom double-necked flask, 0.14 g (0.10 mmol) of Compound 5 and 0.057 g (0.25 mmol) of IC-Cl-delta were weighed and dissolved in 10 mL of toluene. Under nitrogen protection, 0.2 mL of acetic anhydride and 0.1 mL of boron trifluoride diethyl ether were added, and the mixture was stirred at room temperature for 30 minutes. The solvent was removed by rotary evaporation. The product was purified by silica gel column chromatography using dichloromethane and petroleum ether as eluents. The purified product was washed with methanol to obtain the target product 2, which was a black solid (0.13 g, 0.082 mmol). The 1H NMR spectrum of Compound 2 is as follows: 1 H NMR (400MHz, Chloroform-d) δ8.65 (d, J=6.4Hz, 2H), 7.91-7.79 (m, 2H), 7.68 (dd, J=5.6, 1.6Hz, 2H), 4.76 (t, J=7.2Hz, 2H), 3.21 (t, J=8.0Hz, 2H), 2. 12 (m, 2H), 1.98 (m, 4H), 1.72-1.56 (m, 4H), 1.54-1.46 (m, 3H), 1.47-1.28 ( m, 19H), 1.23-0.87 (m, 40H), 0.76 (t, J=6.8Hz, 12H), 0.70 (t, J=6.8Hz, 6H). The mass spectrometry data for compound 2 are: MALDI-HRMS m / z: calcd for C 88 H 102 Cl2N 10 O2S5 [M+]: 1560.6168; found: 1560.6187.
[0058] Example 3:
[0059] Organic solar cells with the electron acceptor material of this application as the active layer are prepared.
[0060] The two organic photovoltaic materials prepared in Examples 1 and 2 were dissolved in chloroform to prepare a solution of 5 mg / mL. The solution was then spin-coated onto a glass slide at 1500 rpm. The resulting thin films were analyzed using a Lambda 365 UV-Vis spectrophotometer with a scanning range of 300-1100 nm to obtain the UV-Vis absorption spectra. The UV-Vis absorption spectra of compounds 1-2 are shown below. Figure 3 As shown, the thin films of the compounds exhibit significant absorption in the 650-1000 nm range, with a wide absorption range and a maximum absorption peak located at 800-900 nm. Compound 1 has an optical bandgap of 1.25 eV, and compound 2 has an optical bandgap of 1.26 eV. Blending these compounds with wide-bandgap donor materials that complement their absorption ranges is beneficial for preparing photovoltaic devices and achieving ideal photoelectric conversion efficiency.
[0061] Fabrication and testing of a solar cell device with an imine bond-containing electron acceptor:
[0062] Conventional devices based on donor D18: fused-ring electron acceptors are fabricated using an ITO / 2PACz / D18:Acceptors / PNDIT-F3N / Ag structure. The specific steps are as follows:
[0063] First, the surface of the indium tin oxide (ITO) glass substrate was swept with an airflow to remove dust particles. Then, under ultrasonic treatment, it was washed for 10 minutes each with 3-5 vol% detergent (twice), deionized water (six times), acetone (once), and isopropanol (once). After cleaning, the glass was dried overnight in an oven at 80°C and stored for later use. A dry petri dish containing the ITO glass was placed in a UV cleaner for UV ozone surface treatment for 12 minutes. Next, the glass slide was fixed in a spin coater, and an ethanol solution of (2-(9H-carbazole-9-yl)ethyl)phosphonate (2PACz) was uniformly coated onto the ITO substrate at 3500 rpm for 20 seconds. Annealing was then performed in air at 140°C for 15 minutes. After annealing, the substrate was transferred to a glove box under a nitrogen atmosphere. Using chloroform as a solvent, an active layer solution of D18:Acceptors (donor to acceptor ratio of 1:1) was prepared, with 1-chloronaphthalene as an additive, and its volume percentage concentration set at any value between 0.2% and 1.2%, and the total solute concentration set at 12-16 mg / mL. The substrate containing the 2PACz thin film layer was placed in a spin coater with a spin speed of 2000-4000 rpm and a spin coating time of 30 seconds. After spin coating, the material covering the common electrode was removed, and the substrate was annealed. The annealing temperature was set at any value between 70 and 90°C in 5°C intervals, and the annealing time was set at any value between 5 and 15 minutes in 2-minute intervals. The optimal active layer thickness was approximately 110 nm. Further, a PNDIT-F3N methanol solution with a concentration of 1 mg / mL and containing glacial acetic acid additive (v / v: 0.5%) was prepared and coated onto the active layer with a spin speed of 3500 rpm and a spin coating time of 30 seconds. Finally, a 1×10⁻⁶ ppm solution was applied to the substrate. -4 Under a vacuum of Pa, a silver electrode with a thickness of approximately 100 nm was deposited by physical vapor deposition, resulting in an effective device area of 0.05 square centimeters. Using an Orielsol 3A (Newport) as a solar simulator, the fabricated device was placed under standard sunlight at AM 1.5G (100 mW / cm2), and current density-voltage (JV) data were acquired using a Keithley 2400 semiconductor analyzer.
[0064] The photovoltaic parameters of solar cells fabricated using compounds 1-2 as electron acceptors and D18 as donor materials are summarized in the table below:
[0065] compound Open circuit voltage (V) <![CDATA[Short-circuit current density (mAcm -2 )]]> Fill factor (%) Photoelectric conversion efficiency (%) Formula 1 0.809 28.73 72.42 16.8 Formula 2 0.835 27.84 68.97 16.0
[0066] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.
Claims
1. An imine bond-containing fused-ring electron acceptor material, characterized by, The imine-containing narrow-band-gap electron-accepting material has a molecular structure represented by the following general formula: wherein the central core moiety is an eight-membered aromatic fused heterocyclic unit; X1 is selected from the group consisting of chalcogens, including oxygen atom, sulfur atom and selenium atom; R1 and R2 are each independently selected from the group consisting of C1-C26 alkyl, C1-C24 alkoxy, C1-C24 alkylthio, C1-C26 partially fluorinated alkyl; The EG unit is an electron-deficient functional group or a substituent unit with electron-withdrawing ability, and is selected from any one of the following groups: wherein R3 is hydrogen atom, halogen, hydroxyl, nitro, cyano, ester group (such as C1-C20 alkoxyacyl), carbonyl C1-C20 alkyl or C1-C20 alkoxy.
2. A preparation of a fused ring electron acceptor material containing an imine bond, which is suitable for use in the fused ring electron acceptor material containing an imine bond according to claim 1, characterized by The method comprises the following steps: S1, the silylation reaction is carried out under the following conditions: tetrahydrofuran is used as the solvent, n-butyllithium is used as the strong base, the molar ratio of compound A to the strong base is 1:2-1:4, the reaction is carried out at a temperature of-78-70°C for 1-2 hours, then trimethylsilyl chloride (TMSCl) is added as the reactant, the molar ratio of the substrate to the reactant is 1:3-1:4, and the reaction is carried out at a temperature of 0-30°C for 5-10 hours; S2, the nitrosylation reaction is carried out under the following conditions: a polar organic solvent is used as the solvent, nitrosyl tetrafluoroborate is used as the nitrosylation reagent, the molar ratio of compound B to the nitrosylation reagent is 1:2-1:4, and the reaction is carried out at a temperature of 0-30°C for 1-3 hours to obtain compound C, wherein the polar organic solvent includes but is not limited to dimethyl sulfoxide, N,N'-dimethylformamide, N-methylpyrrolidone, acetonitrile, chlorobenzene and chloroform; S3, the Knoevenagel condensation reaction is carried out under the following conditions: an aromatic solvent is used as the solvent, an acid anhydride and boron trifluoride etherate complex are used as the catalyst, the molar ratio of the two is 1:0.1-1:1.5, the molar ratio of compound C to the EG type end group is 1:3-1:4, and the reaction is carried out at a temperature of 0-50°C for 30-60 minutes to obtain a compound having a structure represented by formula 1; wherein the aromatic solvent includes but is not limited to toluene, xylene, mesitylene, chlorobenzene and dichlorobenzene, and the acid anhydride includes but is not limited to acetic anhydride, propionic anhydride, valeric anhydride, succinic anhydride, maleic anhydride and glutaric anhydride.
3. Use of the imine-containing electron-accepting material according to claim 1 in the preparation of a photoelectric functional device. 4.The application of the imine bond-containing fused-ring electron acceptor material according to claim 3, characterized in that, The photoelectric functional device includes an organic photovoltaic cell, a photodetector, an organic field effect device and an organic light-emitting semiconductor device.