CN111440191A - A-D-A type indacenodithiophene small molecule with nuclear methyl group and preparation method thereof - Google Patents

Abstract

The invention discloses an A-D-A type indacenodithiophene core-terminal methyl small molecule and a preparation method thereof. The target product is obtained by reacting 6-methyl-3- (dicyanomethylene) indolone with indacenobithiophene under the protection of inert gas and purifying by column chromatography. The rigidity of the framework plane of the indacenodithiophene nucleus is beneficial to improving the effective conjugation length and promoting the carrier migration in molecules; meanwhile, the bulky non-coplanar side chains distributed on two sides of the framework can inhibit long-range ordered accumulation, provide a pseudo-three-dimensional charge transfer channel, and form an acceptor-donor-acceptor (A-D-A) conjugated structure with an electron-withdrawing group, so that the spectrum absorption of the material can be widened and enhanced, and the material can be applied to the construction of high-efficiency organic solar cell materials. The conjugated micromolecule has narrow band gap, has better absorption in the ultraviolet and visible light range, is used as an acceptor material in an organic solar cell, and obtains good device efficiency.

Description

A-D-A type indacenodithiophene small molecule with nuclear methyl group and preparation method thereof

Technical Field

The invention relates to the technical field of organic solar cells, in particular to an A-D-A type indacenobithiophene core-terminal methyl small molecule and a preparation method thereof.

Background

Current human activities and industrial development require a large amount of energy, mostly obtained by burning fossil fuels, but their use has proven to be the main cause of climate change. The solar energy has great potential to become the next generation energy source due to the advantages of huge reserves, cleanness, no pollution, no region limitation and the like. Currently, inorganic silicon solar cells have been widely used in industry because of their stable and high photoelectric conversion efficiency. However, since the silicon single crystal processing technology is complex, the purity requirement is high, and the refining of the high-purity silicon easily causes environmental pollution, the cost for manufacturing the inorganic silicon solar cell is high, the energy consumption is high, the environmental protection is not facilitated, and the further popularization and application of the inorganic silicon solar cell are limited.

Organic solar cells have attracted considerable attention in recent years due to their advantages of being lightweight, low-priced, flexible, translucent, and capable of being produced in a large area. Due to the special spherical space structure of the fullerene derivative, electrons can be delocalized on the whole molecular surface, the fullerene derivative has high electron mobility and high electron affinity, and can perform ultra-fast photoinitiation charge transfer and separation when being blended with a donor material, so that the fullerene derivative is popular in an organic photovoltaic cell acceptor material for a long time. However, the fullerene derivative has very weak absorption in an ultraviolet visible light region, is not easy to carry out chemical modification, so that the energy level and the absorption spectrum of the fullerene derivative are not easy to adjust, and after the fullerene derivative and a donor material form a blended film, the fullerene is easy to migrate and aggregate, so that the appearance of the film is unstable, and further development of the film is limited.

Novel non-fullerene receptors are diverse in variety, are easy to chemically modify, and generally have strong absorption in the ultraviolet and visible region. Compared with a polymer receptor, the small molecule receptor has the characteristics of fixed and definite structure and molecular weight, easiness in purification, no batch difference and the like. The Indacenodithiophene (IDT) structure has a large and rigid plane conjugated structure as an aromatic condensed ring, can effectively enhance intermolecular charge transfer and intermolecular effective pi-pi overlap, has a wide light absorption range, and is an effective unit for constructing a non-fullerene small molecule receptor. Therefore, the development of a novel small molecule acceptor material with Indacenodithiophene (IDT) structure as a core has been a research focus in the field.

Disclosure of Invention

The invention aims to provide an A-D-A type indacenodithiophene core-terminal methyl small molecule and a preparation method thereof. The invention relates to a non-fullerene solar cell device which is applied to the active layer and contains A-D-A type indacenodithiophene nucleus terminal methyl small molecules.

The technical scheme adopted by the invention is as follows: A-D-A type indacenodithiophene small molecule with a methyl group at the core terminus, which is characterized in that: has a structure shown in formula I as follows:

the invention also aims to provide a preparation method of the A-D-A type indacenobithiophene core-terminal methyl small molecule, which is characterized by comprising the following steps:

the method comprises the following steps: synthesis of SJ-CHO:

(1) to a dried 100m L nitrogen bottle, 0.5mmol of IDT-CHO and 0.6mmol of tributyl (1, 3-dioxazolidine-2-methyl) phosphine bromide were added, and 20m L of anhydrous tetrahydrofuran was added, followed by magnetic stirring for 5min to sufficiently dissolve;

(2) adding 1.5mmol of sodium hydride into the reaction nitrogen bottle under the ice bath condition, removing the ice bath after the addition, heating to room temperature, and reacting for 16 hours under the room temperature condition;

(3) after the reaction is finished, quenching redundant NaH by using a cooled HCl solution with the mass fraction of 10%, adjusting the pH value of the reaction mixture to be acidic, and stirring for 4-5h at room temperature;

(4) concentrating the contents of the reaction flask, adding 50m L ethyl acetate to extract the organic layer, washing the organic layer with water, then with brine, drying over anhydrous magnesium sulfate, filtering and evaporating to dryness to obtain a crude product, purifying the crude product by silica gel column chromatography with dichloromethane/petroleum ether volume ratio of 2: 1 as mobile phase, purifying and then performing rotary evaporation to obtain a yellow solid with a yield of 60%,¹H NMR(400MHz,CDCl₃,ppm):9.56(d,J＝7.7Hz,2H),7.53-7.42(m,4H),7.38(s,2H),7.14-7.02(m,16H),6.44(dd,J＝15.4,7.7Hz,2H),2.54(t,J＝7.9Hz,8H),1.53(s,8H),1.35–1.25(m,24H),0.85(s,12H).

step two: synthesis of SJ-IC-M:

(1) adding 0.3mmol SJ-CHO, 1.8mmol 6-methyl-3- (dicyanomethylene) indolone, 50m L chloroform and 1m L pyridine into a two-necked flask, vacuumizing and filling nitrogen for three times, circulating, and deoxidizing the mixture with nitrogen for 30min under the nitrogen atmosphere;

(2) the mixture is reacted and refluxed for 12h at 65 ℃;

(3) after the reaction was completed, it was cooled to room temperature, and the mixture was poured into 400m L of methanol for washing, magnetically stirred for 12 hours, and then suction-filtered to obtain a crude product.

(4) The crude product was purified via dichloromethane/petroleum ether 1: purifying by silica gel column chromatography as mobile phase, purifying, performing rotary evaporation, vacuum drying the product in a vacuum drying oven at 50 deg.C for one day to obtain purple solid with yield of 50%,¹H NMR(400MHz,CDCl₃,ppm):8.56(s,2H),8.46(s,2H),8.36(d,J＝11.7Hz,2H),7.78(d,J＝7.7Hz,2H),7.53(d,J＝10.9Hz,4H),7.43(d,J＝14.7Hz,2H),7.36(s,2H),7.12(q,J＝8.0Hz,16H),2.57(dd,J＝14.0,6.4Hz,14H),1.58(d,J＝8.3Hz,8H),1.30(s,24H),0.86(d,J＝7.4Hz,12H).

the other technical scheme of the invention is as follows: a preparation method of a non-fullerene solar cell device with a small molecule of an A-D-A type indacenodithiophene nucleus terminal methyl as an acceptor is characterized by comprising the following steps:

the solar cell comprises an ITO glass layer, a PEDOT PSS anode interface layer arranged on the ITO glass layer, an active layer containing SJ-IC-M arranged on the PEDOT PSS anode interface layer, a PDINO cathode interface layer arranged on the active layer, and an Al electrode layer arranged on the PDINO cathode interface layer.

The other technical scheme of the invention is as follows: a method for synthesizing A-D-A type indacenodithiophene nucleus-terminated methyl micromolecule is characterized by comprising the following steps: the reaction equation of the specific synthetic route is as follows:

compared with the prior art, the invention has the beneficial effects that:

a novel non-fullerene micromolecule organic functional material is developed, and compared with the existing inorganic solar cell, the energy consumption of the prepared organic photovoltaic device is less, the pollution to the environment is less, and the organic photovoltaic device is more energy-saving and environment-friendly. In addition, the A-D-A type indacenodithiophene small molecule with a core-terminal methyl group can be dissolved in common organic solvents such as chloroform, dichloromethane, tetrahydrofuran, ethyl acetate and the like, and can be processed by a solution processing mode.

Meanwhile, compared with a fullerene receptor material, the large and rigid plane conjugated structure effectively enhances intermolecular charge transmission and intermolecular effective pi-pi overlap, widens the absorption range of the fullerene receptor material in an ultraviolet visible light region, and improves the energy levels of HOMO and L UMO of molecules by methyl at two ends so as to enable the molecules to be more matched with the energy levels of a donor material.

Drawings

FIG. 1 is a structural diagram of a small molecule of A-D-A type indacenodithiophene core terminal methyl group of the present invention.

FIG. 2 is a schematic structural diagram of an A-D-A type indacenodithiophene core-terminal methyl group-based small molecule solar cell device.

FIG. 3 is a nuclear magnetic hydrogen spectrum of a small molecule of A-D-A type indacenodithiophene nuclear-terminal methyl group of the present invention.

FIG. 4 is a specific reaction equation of a small molecule of A-D-A type indacenodithiophene core-terminal methyl group according to the present invention.

Detailed Description

The invention is further described below with reference to the accompanying drawings.

The reaction equation of the invention is shown in figure 4, and the specific reaction steps are as follows: a synthesis method of a small molecule of A-D-A type indacenodithiophene nuclear terminal methyl comprises the following steps:

(1) SJ-CHO Synthesis by adding 0.5mmol IDT-CHO and 0.6mmol tributyl (1, 3-dioxazolidine-2-methyl) phosphonium bromide to a dried 100m L nitrogen bottle and 20m L anhydrous tetrahydrofuran, stirring magnetically for 5min to dissolve completely, adding 1.5mmol sodium hydride to the nitrogen bottle under ice bath, removing the ice bath and raising the temperature to room temperature after the addition is completed, reacting at room temperature for 16h, quenching the excess NaH with a cooled 10% by mass HCl solution, adjusting the reaction mixture to acidic pH, stirring at room temperature for 4-5h, concentrating the contents of the reaction bottle, adding 50m L ethyl acetate to extract the organic matter, washing the organic layer with water, then washing with brine, drying over anhydrous magnesium sulfate, filtering and evaporating to dryness to obtain a crude product, purifying by dichloromethane/petroleum ether volume ratio 2: 1 as mobile phase silica gel, purifying, and performing column chromatography to obtain a yellow solid with a yield of 60%.

(2) SJ-IC-M is synthesized by adding 0.3mmol SJ-CHO, 1.8mmol 6-methyl-3- (dicyanomethylene) indolone, 50M L chloroform and 1M L pyridine into a two-necked flask, vacuumizing and charging nitrogen, circulating for three times, deoxidizing the mixture by nitrogen for 30min under nitrogen atmosphere, reacting and refluxing the mixture at 65 ℃ for 12h, after the reaction is finished, cooling to room temperature, pouring the mixture into 400M L methanol for washing, magnetically stirring for 12h, then carrying out suction filtration to obtain a crude product, purifying the crude product by using dichloromethane/petroleum ether 1:1 as mobile phase silica gel column chromatography, carrying out rotary evaporation after purification, putting the product into a vacuum drying oven, and carrying out vacuum drying at 50 ℃ for one day to finally obtain a purple solid with the yield of 50%.

Claims (4)

1. A-D-A type indacenodithiophene small molecule with a methyl group at the core terminus, which is characterized in that: has a structure shown in formula I as follows:

2. the small molecule containing A-D-A type indacenodithiophene core terminal methyl group with the structure as shown in formula I in claim 1, which comprises the following steps:

synthesis of SJ-IC-M:

(1) adding 0.3mmol SJ-CHO, 1.8mmol 6-methyl-3- (dicyanomethylene) indolone, 50m L chloroform and 1m L pyridine into a two-necked flask, vacuumizing and filling nitrogen for three times, circulating, and deoxidizing the mixture with nitrogen for 30min under the nitrogen atmosphere;

(2) the mixture is reacted and refluxed for 12h at 65 ℃;

(3) after the reaction was completed, it was cooled to room temperature, and the mixture was poured into 400m L of methanol for washing, magnetically stirred for 12 hours, and then suction-filtered to obtain a crude product.

(4) And purifying the crude product by taking dichloromethane/petroleum ether 1:1 as mobile phase silica gel column chromatography, performing rotary evaporation after purification, putting the product into a vacuum drying oven, and performing vacuum drying at 50 ℃ for one day to finally obtain a purple solid with the yield of 50%.

3. A non-fullerene solar cell device preparation according to claim 1, wherein:

the solar cell comprises an ITO glass layer, a PEDOT PSS anode interface layer arranged on the ITO glass layer, an active layer containing SJ-IC-M arranged on the PEDOT PSS anode interface layer, a PDINO cathode interface layer arranged on the active layer, and an Al electrode layer arranged on the PDINO cathode interface layer.

4. The method for synthesizing a small molecule of A-D-A type indacenodithiophene nuclear-terminal methyl according to claim 1, wherein the method comprises the following steps: the reaction equation of the specific synthetic route is as follows:

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