Preparation method of aromatic nitrile compound and application of aromatic nitrile compound in photovoltaic field

Abstract

The invention relates to the field of photovoltaics, in particular to a preparation method and application of an aromatic nitrile compound shown as a formula (I). The structural formula of the formula (I) is as follows: # imgabs0. The preparation method provided by the invention can be used for obtaining a product with high reaction yield and high product purity; the synthesis reaction raw materials are easy to obtain, the reaction conditions are mild, the operation is easy to control, the raw materials are safe and reliable, toxic substances are prevented from being used, and a foundation can be laid for later industrial enlarged production.

Description

Technical Field

[0001] The present invention relates to the field of photovoltaics, and particularly to a preparation method and application of an aromatic nitrile compound. Background Art

[0002] A solar cell includes a base layer, a hole transport layer, an active layer, an electron transport layer, and an electrode layer. The level of the photoelectric conversion efficiency directly affects the quality of the solar cell. Polymer donors (such as PCDTBT) and small molecule acceptors (such as the Y6 series) are the current mainstream types of photovoltaic materials. Non-fullerene acceptors (NFAs) have become a research hotspot due to their high absorption coefficient and adjustable energy levels.

[0003] The current challenges of photovoltaic materials are, firstly, the efficiency bottleneck: it is difficult for the photoelectric conversion efficiency (PCE) of traditional materials to exceed 20%; secondly, the stability problem: molecular aggregation and interfacial defects result in insufficient device lifetime.

[0004] The cyano group and aromatic ring structure of the compound of formula (I) can lower the LUMO energy level (about -3.8 eV), forming an energy level difference of 0.6 eV with common donor materials (such as PM6, HOMO ≈ -5.4 eV), which promotes exciton separation. In Patent CN108864135B, a compound with a similar structure is used in the active layer of an organic photovoltaic device, with an open-circuit voltage (Voc) reaching 0.85 V and a PCE reaching 12.5%. The high polarity of the aromatic ring substituents can improve the contact between the electrode / active layer interface and reduce charge recombination. For example, in Patent CN101541890A, a compound containing a biphenyl structure is used as the hole transport layer, and the device fill factor (FF) is increased to 75%.

[0005] However, the known synthesis methods in the current literature have disadvantages such as long reaction steps, high reagent costs, the need for noble metal catalysis, harsh reaction conditions, complex post-treatment, low yield, and poor economy, and are not suitable for process scale-up production. Therefore, it is of great significance to optimize and develop the synthesis method of this compound. Summary of the Invention

[0006] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a preparation method of the compound of formula (I) with easily available reaction raw materials, mild reaction conditions, easy operation control, safety and reliability, and high yield, so as to solve the problems raised in the above background art.

[0007] The present invention overcomes the disadvantages of low yield and poor economy in previous literature.

[0008] To achieve the above purpose and other related purposes, the present invention provides a preparation method of an aromatic nitrile compound of formula (I), which is characterized by including the following steps:

[0009]

[0010] Step (1): 2,4,5,6-tetrachloroisophthalonitrile and diphenylamine react in a reaction solvent under the action of a catalyst to form a compound of formula (I).

[0011] Preferably, the reaction solvent is selected from one or more of acetonitrile, DMF, dichloromethane, chloroform, DME, tetrahydrofuran, 2-methyltetrahydrofuran.

[0012] Preferably, in step (1), the catalyst is selected from one or more of palladium catalysts, copper catalysts, and nickel catalysts.

[0013] Preferably, in step (1), the reaction temperature is 70 - 90 °C, preferably 80 °C; the reaction time is 40 - 72 hours, preferably 40 - 72 hours.

[0014] The present invention also provides the application of the compound shown in formula (I) in the photovoltaic field. The compound of formula (I) has the following effects: light absorption optimization effect: the strong electron-withdrawing effect of the cyano group redshifts the absorption spectrum to the near-infrared region (700–1000 nm), covering a wider solar spectrum; charge transport enhancement effect: the planar configuration of the polyaromatic ring promotes the ordered packing between molecules, and the carrier mobility can reach 10-3 cm 2 ·V-1·si1; stability improvement effect: the symmetric structure and rigid core reduce film defects, inhibit oxygen / moisture penetration, and the device life is extended to 1000 hours (85 °C aging test). Description of the Drawings

[0015] Figure 1 It is the NMR spectrum of the compound of formula (I) in Example 1. Detailed Embodiments

[0016] The method of the present invention will be described below through specific examples. It should be understood that these examples are used to illustrate the basic principles, main features, and advantages of the present invention, and the present invention is not limited by the scope of the following examples; the implementation conditions adopted in the examples can be further adjusted according to specific requirements, and the implementation conditions not specified are usually the conditions in conventional experiments.

[0017] In the following examples 1 The 1H NMR spectra were measured using a Bruker instrument (400 MHz), and the chemical shifts are expressed in ppm. Tetramethylsilane internal standard (0.00 ppm) was used. 1 Representation method of 1H NMR: s = singlet, d = doublet, t = triplet, q = quartet, m = multiplet, br = broad peak, dd = doublet of doublets, dt = doublet of triplets. When coupling constants are provided, the unit is Hz.

[0018] The mass spectrometry was determined using an LC / MS instrument, and the ionization method was ESI.

[0019] High-performance liquid chromatography instrument models: Agilent 1260, Thermo Fisher U3000; chromatographic column model: Waters xbrige C18 (4.6*150mm, 3.5μm); mobile phase: A: CAN, B: Water (0.1% H 3 PO 4 ); flow rate: 1.0 mL / min; gradient: 5% A for 1 min, increase to 20% A within 4 min, increase to 80% A within 8 min, 80% A for 2 min, back to 5% A within 0.1 min; wavelength: 220 nm; column oven: 35°C.

[0020] TLC: Thin-layer chromatography. The thin-layer chromatography silica gel plates used are Yantai Huanghai HSGF254 or Qingdao GF254 silica gel plates. The specifications of the silica gel plates used in thin-layer chromatography (TLC) are 0.2 mm - 0.3 mm, and the specifications of the silica gel plates used for separating and purifying products by thin-layer chromatography are 0.4 mm - 0.5 mm.

[0021] Column chromatography generally uses silica gel with a mesh size of 200 - 300 from Yantai Huanghai as the carrier.

[0022] In the following examples, unless otherwise specified, all temperatures are in Celsius. Unless otherwise specified, various starting materials and reagents are commercially available or synthesized according to known methods. Commercially available raw materials and reagents are used directly without further purification, unless otherwise specified. Commercially available manufacturers include but are not limited to Sinopharm Group, J&K Scientific Ltd., TCI (Shanghai) Chemical Industry Development Co., Ltd., Shanghai Bide Pharmaceutical Technology Co., Ltd., and Shanghai Merck Chemical Technology Co., Ltd., etc.

[0023] Unless otherwise specified in the examples, the solution in the reaction refers to an aqueous solution.

[0024] Unless otherwise specified in the examples, the reaction temperature is room temperature (20°C - 30°C).

[0025] The progress of the reaction in the examples was monitored by thin-layer chromatography (TLC). The eluent systems for column chromatography used to purify compounds or the developing agent systems for thin-layer chromatography include: A: petroleum ether and ethyl acetate system; B: dichloromethane and methanol system; C: n-hexane: ethyl acetate; where the volume ratio of the solvents varies according to the polarity of the compound, and a small amount of acidic or basic reagents can also be added for adjustment, such as acetic acid or triethylamine, etc.

[0026] The preferred embodiments of the present invention will be described in detail below.

[0027] Example 1

[0028] Synthesis of Compound of Formula (I)

[0029]

[0030] Diphenylamine (84.57 g, 0.50 mol) was dissolved in 2-methyltetrahydrofuran (120 mL). At 0 °C, NaH (60%, 20.99 g, 0.70 mol) was slowly added in portions. After addition, the temperature was maintained and stirred for 0.5 hour until no gas was evolved. A solution of 2,4,5,6-tetrachloroisophthalonitrile (26.60 g, 0.10 mol) in 2-methyltetrahydrofuran (40 mL) was slowly added dropwise to the reaction mixture. The temperature was maintained at about 80 °C. After dropwise addition, the mixture was stirred at a constant temperature for 48 hours. TLC (petroleum ether: ethyl acetate = 3:1) showed that the reaction was complete. The system was cooled to 0 °C. Water (100 mL) was slowly added to quench the reaction, and then the mixture was stirred at room temperature for 0.5 hour. The mixture was filtered, and the filter cake was washed with water (50 mL × 2). The crude product obtained after suction drying was slurried with EA (200 mL) for 2 hours. The mixture was filtered, and the filter cake was washed with EA (50 mL × 2). After suction drying, the solvent was evaporated to obtain 65.70 g of a yellow solid, with a yield of 82.47% and a purity of 97.40%.

[0031] 1 1H NMR (400 MHz, DMSO-d6) δ 7.33~7.25 (m, 16H), 7.15~7.00 (m, 24H).

[0032] The above examples are only for illustrating the technical concept and features of the present invention, and the purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. It should not be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit and essence of the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for preparing an aromatic nitrile compound of formula (I), characterized in that: The steps include: Step (1): 2,4,5,6-tetrachloroisophthalonitrile and diphenylamine are reacted with a catalyst in a reaction solvent to generate a compound of formula (I).

2. The preparation method according to claim 1, characterized in that: In step (1), the reaction solvent is selected from one or more of acetonitrile, DMF, dichloromethane, chloroform, DME, tetrahydrofuran, and 2-methyltetrahydrofuran.

3. The preparation method according to claim 1, characterized in that: In step (1), the catalyst is selected from one or more of a palladium catalyst, a copper catalyst, and a nickel catalyst.

4. Application of the compound represented by formula (I) in the photovoltaic field.

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