CN109608475B - A '-pi-A' type organic small molecule and preparation method and application thereof - Google Patents

Abstract

The invention provides an A '-pi-A' type organic small molecule and a preparation method and application thereof. The A ' -pi-A ' type organic micromolecule takes a TPTI unit with weak electron absorption as a central nucleus A, 3-hexylthiophene, 3' -dioctyl- (2,2':5', 2' -trithiophene) as a pi conjugate bridge, and 1, 3-indandione and 3-ethyl rhodanine as electron absorption terminals A '. The preparation method is characterized in that intermediates M1 and A' are subjected to Knoevenagel condensation reaction under the action of a solvent and a catalyst to obtain the compound. The A ' -pi-A ' type organic micromolecule can realize the regulation and control of the photoelectric properties of micromolecule structure, absorption spectrum, band gap, front line molecular orbit energy level and the like by changing the pi bridge and different electron-withdrawing terminals (A '), can prepare micromolecule photoelectric functional materials with excellent photoelectric properties, and can be applied to the preparation of solar cells.

Description

A '-pi-A' type organic small molecule and preparation method and application thereof

Technical Field

The invention relates to the technical field of solar cells, in particular to an A '-pi-A' type organic micromolecule based on a thieno [2',3': 5.6] pyrido [3,4-g ] thieno [3,2-c ] -isoquinoline-5, 11(4H,10H) -diketone (TPTI for short) structural unit, and a preparation method and application thereof.

Background

An organic small molecule solar cell is a device which directly converts solar energy into electric energy by utilizing a photovoltaic effect based on organic small molecules. The composite material has the advantages of light weight, low price, simple preparation process, good controllability of the chemical structure of the material and the like, and has obvious advantages in future application. Since the last 90 s, through continuous efforts of nearly thirty years, the energy conversion efficiency (PCE) of organic solar cells has been steadily improved, showing broad application and research and development prospects. Currently, PCEs of acceptor-donor-acceptor (a-D-a) type organic small molecule tandem solar cells based on the indacene unit have exceeded 17% (Meng L, Zhang Y, Wan X, et al. organic and solution-processed solar cells with 17.3% efficiency. science,2018,361, 1094-. PCEs have also exceeded 10% for organic solar cells based on small molecule donor materials (Zhang H, Liu Y, Sun Y, et al. development high-performance small organic solar cells via large planar structure and an electron-with-driving central units chemical Communications,2016,53, 451-. However, the organic small molecule solar cell still has the problems of low carrier mobility, complex synthesis steps, poor stability and the like, and a new organic small molecule donor material with excellent photoelectric properties needs to be developed.

Thieno [2',3': 5.6] pyrido [3,4-g ] thieno [3,2-c ] -isoquinoline-5, 11(4H,10H) -dione (TPTI) is a conjugated five-ring fused ring system containing an amide bond, and has good planarity and weak electron withdrawing property. The bulk heterojunction organic solar cell constructed by using the conjugated polymer containing the TPTI unit as a donor and the fullerene derivative (such as PCBM) as an acceptor shows good photovoltaic performance, and PCE of the bulk heterojunction organic solar cell exceeds 8% (Cao J, Chen S, Qi Z, et al. an effective selected conjugated polymer for organic solar cells, RSC Advances,2014,4,5085-5087), which shows that the TPTI unit has great development potential in the aspect of constructing high-efficiency organic solar cell materials. However, few organic small molecule solar cell donor materials based on a TPTI unit are reported at present, and particularly, an a ' -pi-a ' type organic small molecule donor material in which a TPTI unit with weak electron absorption is used as a central core (a), an electron absorption unit (such as 1, 3-indandione or 3-ethyl rhodanine) is used as a terminal (a '), and an aromatic heterocyclic unit is a pi-conjugated bridge, and a preparation method and photovoltaic application thereof are not reported yet.

Disclosure of Invention

The invention aims to solve the technical problems of few types of TPTI organic micromolecule solar cell materials, narrow application field and the like in the prior art, provides a TPTI-based A ' -pi-A ' type organic micromolecule, can realize the regulation and control of the photoelectric properties such as micromolecule structure, absorption spectrum, band gap, front line molecule rail energy level and the like by changing a pi bridge and different electron-withdrawing terminals (A '), and achieves the purpose of preparing the micromolecule photoelectric functional material with excellent photoelectric properties. The preparation method is simple and high in recovery rate, and can be applied to preparation of solar cells.

In order to solve the technical problem, the invention provides an A '-pi-A' type organic small molecule, wherein the A '-pi-A' type organic small molecule has a structural formula shown in the following formula I:

in the formula I: r is selected from any one of the following groups:

R₁any one selected from the following groups: -C₆H₁₃、-C₈H₁₇、-C₁₂H₂₅、-C₁₆H₃₃、

A' is selected from any one of the following groups:

as a general technical concept, the invention also provides a preparation method of the a ' -pi-a ' type organic micromolecule, the a ' -pi-a ' type organic micromolecule is obtained by performing Knoevenagel condensation reaction on intermediates M1 and a ' under the action of a solvent and a catalyst, and the intermediate M1 has a structural formula of the following formula III:

in the formula III: r is selected from any one of the following groups:

R₁any one selected from the following groups: -C₆H₁₃、-C₈H₁₇、-C₁₂H₂₅、-C₁₆H₃₃、

In the preparation method, the mol ratio of the intermediate M1 to A' is preferably 1: 3-4.

In the preparation method, the molar ratio of the catalyst to the intermediate M1 is preferably 11-14: 1.

In the preparation method, preferably, the catalyst is one of pyridine, piperidine and triethylamine.

In the above preparation method, preferably, the solvent is one of chloroform and acetonitrile.

In the preparation method, preferably, the intermediate M1 is prepared by the following method:

s1-1, reacting the compound 1 with the compound 2 to obtain a compound 3;

s1-2, heating and reacting the compound 3, palladium acetate, cesium carbonate, tricyclohexyl phosphorus fluoborate and N, N-Dimethylacetamide (DMF) to obtain a compound 4;

s1-3, carrying out a light-shielding reaction on the compound 4 and bromosuccinimide (NBS) to obtain a compound 5;

s1-4, mixing the compound 5, a 3-alkylthiophene tin reagent and tetratriphenylphosphine palladium, and heating to react to obtain a compound 6;

s1-5, reacting the compound 6, N-dimethylacetamide and POCl3 to obtain an intermediate M1;

the compound 1 is

The compound 2 is

The compound 3 is:

the compound 4 is:

the compound 5 is:

the compound 6 is:

the reaction scheme of intermediate M1 is:

in the preparation method, preferably, in S1-1, the molar ratio of the compound 1 to the compound 2 is 2-3: 1.

In the preparation method, preferably, in S1-2, the compound 3, palladium acetate, cesium carbonate and tricyclohexyl fluoroborate are in a molar ratio of 1: 0.6-0.8: 12-16: 1-2.

In the preparation method, preferably, in S1-3, the molar ratio of the compound 4 to NBS is 1: 2-3.

In the preparation method, preferably, in S1-4, the molar ratio of the compound 5, the 3-alkylthiophentinoin and the tetratriphenylphosphoropalatinum is 1: 3-4: 0.04-0.06.

The above preparation method is preferred, in the S1-5, the compound 6, DMF and POCl₃The molar ratio of (A) to (B) is 1: 2-3: 3-5.

As a general technical concept, the present invention also provides an a '-pi-a' type organic small molecule having a structural formula of formula II below:

in the formula II: r is selected from any one of the following groups:

R₁any one selected from the following groups: -C₆H₁₃、-C₈H₁₇、-C₁₂H₂₅、-C₁₆H₃₃、

A' is selected from any one of the following groups:

as a general technical concept, the invention also provides a preparation method of the A '-pi-A' type organic micromolecule, wherein the A '-pi-A' type organic micromolecule is obtained by performing Stille coupling reaction on an intermediate M2 and an intermediate M3 under the action of a solvent and a catalyst;

the intermediate M2 has the following structural formula shown in IV:

the intermediate M3 has the following structural formula V:

in the preparation method, preferably, the intermediate M2 is prepared by the following method:

s2-1, reacting the compound 4, Tetrahydrofuran (THF) and Lithium Diisopropylamide (LDA) at-78 ℃,

s2-2, adding trimethyl tin chloride (Me) continuously₃SnCl) at room temperature to afford intermediate M2,

the compound 4 is:

the reaction scheme of intermediate M2 is:

in the preparation method, preferably, the intermediate M3 is prepared by the following method:

s3-1, heating and reacting the compound 7 and A' under the action of a solvent and a catalyst to obtain a compound M3;

the compound 7 is

The reaction scheme of intermediate M3 is:

in the above preparation method, preferably, the catalyst is tetratriphenylphosphine palladium.

In the above preparation method, preferably, the solvent is toluene or chlorobenzene.

In the preparation method, the mol ratio of the intermediate M2 to the intermediate M3 is preferably 1: 2-3.

In the preparation method, the molar ratio of the catalyst to the intermediate M2 is preferably 0.02-0.05: 1.

In the above preparation method, preferably, in S2-2, the compound 4, LDA and Me₃The mol ratio of SnCl is 1: 2-3: 3-5.

In the preparation method, preferably, in S3-1, the molar ratio of the compound 7 to a' is 1: 2-4.

As a general technical concept, the invention also provides an application of the A '-pi-A' type organic micromolecule in the preparation of solar cells.

In the above application, preferably, the application method is:

(1) spin-coating a conductive film of PEDOT/PSS polymer on the anode;

(2) spin-coating a layer of A '-pi-A' type organic micromolecule and PC₇₁A photoactive layer formed by blending BM;

(3) vacuum evaporating metal calcium as a cathode modification layer;

(4) and evaporating cathode metal aluminum to obtain the solar cell.

Compared with the prior art, the invention has the advantages that:

(1) the invention provides a small molecule with A ' -pi-A ' configuration based on TPTI, which can realize the regulation and control of the photoelectric properties such as small molecule structure, absorption spectrum, band gap, front line molecular orbital energy level and the like by changing a pi bridge and different electron-withdrawing terminals (A '), thereby achieving the purpose of preparing a small molecule photoelectric functional material with excellent photoelectric properties.

(2) The invention provides a TPTI-based micromolecule with A '-pi-A' configuration, which has a controllable absorption spectrum (300-900 nm). And meanwhile, the high-performance high-voltage capacitor has good thermal stability and high open-circuit voltage, which is beneficial to obtaining a high-efficiency device.

(3) The invention provides a preparation method of a small molecule with A '-pi-A' configuration based on TPTI, the synthetic route has the advantages of wide raw material supply, simple and efficient synthesis and the like, and in addition, the method has very high popularization and very good repeatability.

(4) The invention provides a TPTI-based methodApplication of small molecules with A '-pi-A' configuration in preparation of solar cells, wherein the small molecules with the A '-pi-A' configuration are used as donor phase material and acceptor phase material (PC)₇₁BM) is adopted to optimize the photovoltaic performance by means of adjusting the ratio of a donor to a acceptor, additives and the like, the obtained energy conversion efficiency (PCE) reaches 3.82 percent, and the corresponding open-circuit voltage (V) is obtained_oc) Reaches 1.04V, short-circuit current (J)_sc) Reaches 7.04mA/cm²The Fill Factor (FF) reached 52.17%. The result is the first attempt of TPTI type small molecular materials in the aspect of organic solar cells, and shows that the TPTI type small molecular materials have potential research and development and application prospects in the aspect of organic photoelectric functional materials, especially organic solar cell materials.

Drawings

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention.

FIG. 1 is a synthetic scheme of CS6 and CS7 in examples 1 and 2 of the present invention.

FIG. 2 is a synthetic scheme of CS8 and CS9 in examples 3 and 4 of the present invention.

FIG. 3 is a graph showing UV-VIS absorption spectra of CS6, CS7, CS8 and CS9 thin films on a quartz plate in an experimental example of the present invention.

FIG. 4 is a cyclic voltammogram of CS6, CS7, CS8, and CS9 in an experimental example of the present invention.

Fig. 5 is a structural view of a solar cell in an experimental example of the present invention.

Fig. 6 is a graph of current-voltage characteristics (J-V) of an organic small molecule solar cell prepared based on four small molecules CS6, CS7, CS8, and CS9 in an experimental example of the present invention.

Detailed Description

The invention is further described below with reference to the drawings and specific preferred embodiments of the description, without thereby limiting the scope of protection of the invention. The examples described below are intended to facilitate the understanding of the invention without having any limiting effect thereon. The method is a conventional method unless otherwise specified. The reaction mass can be purchased from a publicly available commercial source unless otherwise specified.

Example 1:

a TPTI unit-based A ' -pi-A ' type micromolecule CS6 takes the TPTI unit with weak electron absorption as a central core A, 3-hexylthiophene as a pi conjugate bridge and 1, 3-indandione as an electron absorption terminal A '.

CS6 has the general structural formula of formula I:

wherein R is 2-octyl dodecyl, R₁Is n-hexyl and A' is 1, 3-indandione.

The specific chemical structural formula of CS6 is:

a preparation method of CS6 according to this embodiment, the synthetic route is shown in fig. 1, and the specific preparation method includes the following steps:

(1)2, 5-dibromo-N¹,N⁴-bis (2-octyldodecyl) -N¹,N⁴Synthesis of (di) thiophen-3-yl) terephthalamide (Compound 3).

1.1 in a 250mL three-necked flask under argon atmosphere, 11.6g (30.56mmol) of N- (2-octyldodecyl) thiophen-3-amine (Compound 1), 5mL of triethylamine and 40mL of dried dichloromethane were added.

1.2, 5g (13.89mmol) of 2, 5-dibromoterephthaloyl dichloride (compound 2) was dissolved in 40mL of dry dichloromethane to obtain a mixed solution.

And 1.3, slowly dropwise adding the mixed solution obtained in the step 1.2 into the three-necked bottle obtained in the step 1.1 in ice bath, and raising the temperature to room temperature for reacting overnight after the dropwise adding is finished.

And 1.4, adding water to quench the reaction, extracting dichloromethane to obtain an organic phase, drying the organic phase by using anhydrous magnesium sulfate, filtering, and removing the solvent by rotation to obtain a crude product.

1.5, the crude product is separated and purified by column chromatography (eluent: dichloromethane) to obtain 8.72g of yellow solid, namely 2, 5-dibromo-N¹,N⁴-bis (2-octyldodecyl) -N¹,N⁴Bis (thien-3-yl) terephthalamide, in 60% yield (compound 3). The structural characterization data for this compound is as follows:

hydrogen nuclear magnetic resonance spectroscopy:¹H NMR(400MHz,CDCl₃,δ/ppm)：7.13(dd,J＝5.1,3.2Hz,2H),7.09(s,2H),6.85(br,2H),6.76(dd,J＝5.1,1.2Hz,2H),3.75(br,4H),1.57-1.52(m,2H),1.29-1.24(m,64H),0.90-0.85(m,12H)。

the compound has a correct structure and is 2, 5-dibromo-N according to the nuclear magnetic resonance hydrogen spectrum¹,N⁴-bis (2-octyldodecyl) -N¹,N⁴-bis (thien-3-yl) terephthalamide (compound 3).

(2) Synthesis of 4, 10-bis (2-octyldodecyl) -4, 10-dihydrothieno [2',3':5,6] pyrido [3,4-g ] thieno [3,2-c ] isoquinoline-5, 11-dione (Compound 4).

2.1 under an argon atmosphere, in a 250mL three-necked flask, 8g of Compound 3(7.64mmol), 1.3g of palladium acetate (5.85mmol), 37g of cesium carbonate (113.57mmol), 3.46g of tricyclohexylphosphonium fluoroborate (9.42mmol) and 150mL of N, N-dimethylacetamide were added. The temperature is raised to 120 ℃ and the reaction is carried out for 24 hours.

2.2, cooling to room temperature, adding water to quench the reaction, and extracting with chloroform to obtain an organic phase. The organic phase was dried over anhydrous magnesium sulfate, filtered and the solvent was removed by rotary evaporation to give a crude product.

2.3, the crude product was separated and purified by column chromatography (eluent: petroleum ether: dichloromethane: 10: 1) to obtain 4.25g of a yellow solid, i.e., 4, 10-bis (2-octyldodecyl) -4, 10-dihydrothieno [2',3':5,6] pyrido [3,4-g ] thieno [3,2-c ] isoquinoline-5, 11-dione (compound 4) in 63% yield. The structural characterization data for this compound is as follows:

hydrogen nuclear magnetic resonance spectroscopy:¹H NMR(400MHz,CDCl₃,δ/ppm):8.88(s,2H),7.49(d,J＝5.4Hz,2H),7.10(d,J＝5.5Hz,2H),4.24(s,4H),2.04(s,2H),1.56(s,6H),1.22(s,58H),0.85(m,12H)。

nuclear magnetic resonance carbon spectrum:¹³C NMR(100MHz,CDCl₃,δ/ppm):161.64,139.47,130.04,126.86,126.12,123.67,117.97,117.77,77.32,77.00,76.68,49.74,37.13,31.89,31.85,31.67,29.96,29.60,29.56,29.51,29.31,29.25,26.67,22.66,14.08。

mass spectrum: MS (MALDI-TOF, m/z) C₅₆H₈₈N₂O₂S₂Theoretical value 885.450; found 885.776.

As can be seen from the above, the compound has a correct structure and is 4, 10-bis (2-octyldodecyl) -4, 10-dihydrothieno [2',3':5,6] pyrido [3,4-g ] thieno [3,2-c ] isoquinoline-5, 11-dione (compound 4).

(3) Synthesis of 2, 8-dibromo-4, 10-bis (2-octyldodecyl) -4, 10-dihydrothieno [2',3':5,6] pyrido [3,4-g ] thieno [3,2-c ] isoquinoline-5, 11-dione (Compound 5)

3.1 in a 250mL three-necked flask, 4.42g of Compound 4(5mmol) and 120mL of chloroform were added.

3.2, 2.23g of NBS (12.5mmol) was dissolved in 30mL of DMF to obtain a mixed solution.

3.3, slowly dripping the mixed solution in the step 3.2 into the three-necked bottle in the step 3.1, and reacting at room temperature in a dark place overnight.

3.4, adding water to quench the reaction, and extracting an organic phase by using trichloromethane. The organic phase was dried over anhydrous magnesium sulfate, filtered and the solvent was spun off to obtain the crude product.

3.5, separating and purifying the crude product by column chromatography (eluent: petroleum ether: dichloromethane: 15: 1) to obtain 4.79g of yellow solid, namely 2, 8-dibromo-4, 10-di (2-octyldodecyl) -4, 10-dihydrothieno [2',3':5,6] pyrido [3,4-g ] thieno [3,2-c ] isoquinoline-5, 11-diketone (compound 5) with the yield of 92%. The structural characterization data for this compound is as follows:

hydrogen nuclear magnetic resonance spectroscopy:¹H NMR(400MHz,CDCl₃,δ/ppm):8.70(s,2H),7.07(s,2H),4.16(s,4H),1.98(s,2H),1.58(s,6H),1.29(d,J＝5.5Hz,58H),0.86(dd,J＝12.1,6.5Hz,12H).

nuclear magnetic resonance carbon spectrum:¹³C NMR(100MHz,CDCl₃,δ/ppm):161.15,138.87,129.39,126.88,123.43,120.90,118.84,115.14,77.32,77.20,77.00,76.68,49.78,36.99,31.90,31.86,31.52,29.95,29.61,29.56,29.51,29.32,29.26,26.54,22.67,22.64,14.10,14.08.

mass spectrum: MS (MALDI-TOF, m/z) C₅₆H₈₆Br₂N₂O₂S₂Theoretical value 1043.240; found 1043.737.

As can be seen from the above, the compound has a correct structure and is 2, 8-dibromo-4, 10-bis (2-octyldodecyl) -4, 10-dihydrothieno [2',3':5,6] pyrido [3,4-g ] thieno [3,2-c ] isoquinoline-5, 11-dione (compound 5).

(4) Synthesis of 2, 8-bis (4-hexylthiophen-2-yl) -4, 10-bis (2-octyldodecyl) -4, 10-dihydrothieno [2',3':5,6] pyrido [3,4-g ] thieno [3,2-c ] isoquinoline-5, 11-dione (Compound 6)

4.1 under an argon atmosphere, in a 100mL three-necked flask, 4.17g of Compound 5(4mmol), 9g of 3-hexylthiophenatotin reagent (16mmol), 230mg of tetrakistriphenylphosphine palladium (0.2mmol) and 40mL of toluene were added. The temperature is raised to 120 ℃ and the reaction is carried out for 24 hours.

4.2, cooling to room temperature, extracting with dichloromethane to obtain an organic phase, drying the organic phase with anhydrous magnesium sulfate, filtering, and removing the solvent by rotary removal to obtain a crude product.

4.3, the crude product is separated and purified by column chromatography (eluent: petroleum ether: dichloromethane: 2: 1) to obtain 3.89g of yellow solid, namely 2, 8-bis (4-hexylthiophen-2-yl) -4, 10-bis (2-octyldodecyl) -4, 10-dihydrothieno [2',3':5,6] pyrido [3,4-g ] thieno [3,2-c ] isoquinoline-5, 11-dione (compound 6), with the yield of 80%. The structural characterization data for this compound is as follows:

hydrogen nuclear magnetic resonance spectroscopy:¹H NMR(400MHz,CDCl₃,δ/ppm):8.74(s,2H),7.14(s,2H),7.07(s,2H),6.92(s,2H),4.21(s,4H),2.63(t,J＝7.7Hz,4H),2.03(s,2H),1.64(d,J＝7.7Hz,4H),1.58(s,2H),1.37-1.21(m,72H),0.94-0.84(m,20H)。

nuclear magnetic resonance carbon spectrum:¹³C NMR(100MHz,CDCl₃,δ/ppm):161.46,144.67,139.56,137.99,136.18,129.58,126.80,126.23,123.46,120.49,116.42,113.22,77.32,77.00,76.68,49.47,37.03,31.90,31.88,31.66,30.49,30.37,29.97,29.62,29.56,29.34,29.28,29.00,27.83,26.84,26.69,22.67,22.62,17.51,14.10,13.59。

mass spectrum: MS (MALDI-TOF, m/z) C₇₆H₁₁₆N₂O₂S₄Theoretical value 1218.020; found 1218.325.

As is clear from the above, the compound has a correct structure and is 2, 8-bis (4-hexylthiophen-2-yl) -4, 10-bis (2-octyldodecyl) -4, 10-dihydrothieno [2',3':5,6] pyrido [3,4-g ] thieno [3,2-c ] isoquinoline-5, 11-dione (Compound 6).

(5) Synthesis of 5,5' - (4, 10-bis (2-octyldodecyl) -5, 11- dioxo 4,5,10, 11-tetrahydrothiophene [2',3':5,6] pyrido [3,4-g ] thieno [3,2-c ] isoquinoline-2, 8-diyl) bis (3-hexylthiophene-2-carbaldehyde) (intermediate M1).

5.1 under argon atmosphere, in a 250mL three-necked flask, 4.44g of Compound 6(3.65mmol) and 60mL of 1.2-dichloroethane were added, and 1mL of DMF (10mmol) was slowly added to the reaction system at 0 ℃ to react for 15 min.

5.2, 1.82mL of POCl₃(13.65mmol) was slowly added to the reaction system, and after completion of the dropwise addition, the reaction was carried out at room temperature for 1 hour.

5.3, heating to 80 ℃ and reacting for 24 hours.

And 5.4, cooling to room temperature, adding water to quench the reaction, extracting an organic phase by using trichloromethane, drying the organic phase by using anhydrous magnesium sulfate, and filtering to obtain a crude product.

And 5.5, separating and purifying the crude product by using column chromatography (eluent: petroleum ether: dichloromethane: 1) to obtain 2.65g of red solid, namely the compound 5,5' - (4, 10-bis (2-octyldodecyl) -5, 11- dioxo 4,5,10,11 tetrahydrothiophene [2',3':5,6] pyrido [3,4-g ] thieno [3,2-c ] isoquinoline-2, 8-diyl) bis (3-hexylthiophene-2-formaldehyde), wherein the yield is 57%. The structural characterization data for this compound is as follows:

hydrogen nuclear magnetic resonance spectroscopy:¹H NMR(400MHz,CDCl₃,δ/ppm):10.02(s,2H),8.73(d,J＝5.0Hz,2H),7.20(s,2H),7.15(s,2H),4.21(s,4H),2.97(t,J＝7.0Hz,4H),2.01(s,2H),1.81-1.67(m,4H),1.58(s,2H),1.30(dd,J＝60.3,15.4Hz,72H),0.95-0.80(m,20H)。

nuclear magnetic resonance carbon spectrum:¹³C NMR(100MHz,CDCl₃,δ/ppm):181.39,161.02,153.79,144.40,139.87,136.95,136.11,129.50,127.47,127.04,123.79,118.50,115.32,77.32,77.00,76.68,49.61,37.03,31.88,31.85,31.58,31.54,31.43,29.98,29.63,29.60,29.53,29.32,29.29,29.03,28.60,26.61,22.65,22.64,22.56,14.08,14.05。

mass spectrum: MS (MALDI-TOF, m/z) C₇₈H₁₁₆N₂O₄S₄Theoretical value 1274.041; found 1274.430.

As can be seen from the above, the compound has a correct structure and is an intermediate 5,5' - (4, 10-bis (2-octyldodecyl) -5, 11-dioxo-4, 5,10, 11-tetrahydrothieno [2',3':5,6] pyrido [3,4-g ] thieno [3,2-c ] isoquinoline-2, 8-diyl) bis (3-hexylthiophene-2-carbaldehyde) (intermediate M1).

(6) Synthesis of small molecule CS6

6.1 under argon atmosphere, 0.81g M1(0.63mmoL), 0.37g of 1.3-indandione (2.51mmoL) and 60mL of chloroform were added to a 100mL three-necked flask, respectively, followed by stirring, addition of 1mL of pyridine, stirring and heating to 75 ℃ for 12 hours.

6.2, after the reaction is finished, extracting by dichloromethane, washing by water, drying by anhydrous magnesium sulfate, and filtering to obtain a crude product.

And 6.3, separating and purifying the crude product by column chromatography (eluent: petroleum ether: dichloromethane: 1: 3) to obtain 0.67g of black solid, namely the micromolecule CS6, with the yield of 71%. The structural characterization data of the small molecule is as follows:

hydrogen nuclear magnetic resonance spectroscopy:¹H NMR(400MHz,CDCl₃,δ/ppm):8.48(s,2H),7.84(dd,J＝22.5,6.4Hz,6H),7.66(dd,J＝13.2,6.5Hz,4H),7.06(d,J＝9.3Hz,4H),4.18(s,4H),2.84(t,J＝7.4Hz,4H),2.00(s,2H),1.78-1.57(m,6H),1.53-1.22(m,74H),0.94(t,J＝6.8Hz,6H),0.80(m,12H)。

nuclear magnetic resonance carbon spectrum:¹³C NMR(100MHz,CDCl₃,δ/ppm):190.00,189.16,160.65,158.00,145.99,141.91,140.24,140.16,136.30,134.66,134.47,131.87,131.78,129.18,126.77,123.64,122.80,122.67,122.56,118.75,115.03,77.32,77.00,76.68,49.78,36.90,31.89,31.61,31.37,30.04,29.72,29.64,29.62,29.55,29.52,29.36,29.21,26.73,22.66,22.64,14.09,14.07。

mass spectrum: MS (MALDI-TOF, m/z) C₉₆H₁₂₄N₂O₆S₄Theoretical value 1530.301; found 1531.054.

As can be seen from the above, the product has a correct structure and is a micromolecule CS6 based on TPTI and 1, 3-indandione and shown in a structural formula (1), wherein R is 2-octyl dodecyl, and R is₁Is n-hexyl and A' is 1, 3-indandione.

The micromolecule CS6 of the embodiment is applied to preparing an organic solar cell, the micromolecule CS6 prepared in the embodiment is used as a donor material in the organic solar cell and is used for constructing a bulk heterojunction type organic solar cell together with an acceptor phase material, the structure of the cell is shown in figure 5 and is ITO/PEDOT: PSS/photoactive layer/Ca/Al, and the photoactive layer is formed by micromolecules CS6 and PC shown in structural formula I₇₁BM blending.

The preparation method of the solar cell comprises the following steps:

(1) the anode is made of Indium Tin Oxide (ITO) conductive glass, an anode modification layer PEDOT/PSS polymer conductive film is coated on the ITO conductive glass in a spin mode, and the ITO conductive glass is processed for 15 minutes at the temperature of 150 ℃.

(2) Spin coating a layer of small molecule CS6 and receptor material PC₇₁Photoactive layer (CS 6: PC) formed by blending BM₇₁BM weight ratio of 1: 1, and BM weight ratio of 1: 0.5-2).

(3) After drying for half an hour, metal calcium (about 20nm) is evaporated in vacuum to be used as a cathode modification layer.

(4) Finally, cathode metallic aluminum (about 100nm) is evaporated, and the area of the plated metal (about 4 mm) is controlled by a mask²)。

The photovoltaic performance of the organic solar cell is under simulated sunlight (AM1.5G, 100 mW/cm)²) Testing was performed by Keithley2602 table source, etc.

Example 2:

a TPTI unit-based A ' -pi-A ' type micromolecule CS7 takes a TPTI unit with weak electron absorption as a central core A, 3-hexylthiophene as a pi conjugate bridge and 3-ethyl rhodanine as an electron absorption tail end A '.

CS7 has the general structural formula of formula I:

wherein R is 2-octyl dodecyl, R₁Is n-hexyl, A' is 3-ethyl rhodanine, and the specific chemical structural formula is shown as follows:

a preparation method of CS7 according to this embodiment, the synthetic route is shown in fig. 1, and the specific preparation method includes the following steps:

(1) synthesis of intermediate M1(5,5' - (4, 10-bis (2-octyldodecyl) -5, 11- dioxo 4,5,10, 11-tetrahydrothiophene [2',3':5,6] pyrido [3,4-g ] thieno [3,2-c ] isoquinoline-2, 8-diyl) bis (3-hexylthiophene-2-carbaldehyde)): same as in example 1.

(2) Synthesis of CS 7: to a 100mL three-necked flask, 0.82g of intermediate M1(0.63mmol) and 0.40g of 3-ethylrhodanine (2.51mmol) were added under argon atmosphere, and after stirring, 1mL of pyridine was added, followed by stirring and heating to 75 ℃ for 12 hours. After the reaction is finished, dichloromethane is extracted, washed, dried by anhydrous magnesium sulfate and filtered to obtain a crude product. The crude product was purified by column chromatography (eluent: petroleum ether: dichloromethane: 1) to give 0.63g of brown solid in 65% yield.

Hydrogen nuclear magnetic resonance spectroscopy:¹H NMR(400MHz,CDCl₃,δ/ppm):8.59(s,2H),7.85(s,2H),7.13(s,2H),7.03(s,2H),4.17(m,8H),2.80(t,J＝7.8Hz,4H),2.00(s,2H),1.73-1.63(m,4H),1.59(s,8H),1.40-1.21(m,70H),0.96-0.79(m,22H)。

nuclear magnetic resonance carbon spectrum:¹³C NMR(100MHz,CDCl₃.δ/ppm):191.44,167.18,160.77,151.10,142.28,139.89,135.96,132.34,129.18,127.23,126.76,123.52,122.40,120.37,117.91,114.20,77.32,77.00,76.68,49.58,39.92,37.05,31.90,31.87,31.62,31.08,29.99,29.69,29.64,29.62,29.58,29.37,29.34,29.19,29.12,26.73,22.67,22.63,14.10,12.30。

mass spectrum: MS (MALDI-TOF, m/z) C₈₈H₁₂₆N₄O₄S₈Theoretical value 1560.480; found 1561.074.

As can be seen from the above, the product has a correct structure and is a small molecule CS7 based on TPTI and 3-ethyl rhodanine and shown in a structural formula I, wherein R is 2-octyl dodecyl group, and R is₁Is n-hexyl and A' is 3-ethyl rhodanine.

The micromolecule CS7 of the embodiment is applied to preparing an organic solar cell, the micromolecule CS7 prepared in the embodiment is used as a donor material in the organic solar cell and is used for constructing a bulk heterojunction type organic solar cell together with an acceptor phase material, the structure of the cell is shown in figure 5 and is ITO/PEDOT: PSS/photoactive layer/Ca/Al, and the photoactive layer is formed by micromolecules CS6 and PC shown in structural formula I₇₁BM blending.

The preparation method of the solar cell comprises the following steps:

(1) the anode is made of Indium Tin Oxide (ITO) conductive glass, an anode modification layer PEDOT/PSS polymer conductive film is coated on the ITO conductive glass in a spin mode, and the ITO conductive glass is processed for 15 minutes at the temperature of 150 ℃.

(2) Spin coating a layer of small molecule CS6 and receptor material PC₇₁BM blend (CS 7: PC)₇₁BM weight ratio of 1: 1, which can be implemented at a weight ratio of 1: 0.5-2).

(3) After drying for half an hour, metal calcium (about 20nm) is evaporated in vacuum to be used as a cathode modification layer.

(4) Finally, cathode metallic aluminum (about 100nm) is evaporated, and the area of the plated metal (about 4 mm) is controlled by a mask²)。

The photovoltaic performance of the organic solar cell is under simulated sunlight (AM1.5G, 100 mW/cm)²) Testing was performed by Keithley2602 table source, etc.

Example 3:

A-pi-A' type small molecule CS8 based on TPTI unit: the TPTI unit with weak electron withdrawing property is used as the central core A, 3, 3' -dioctyl- (2,2':5', 2' -trithiophene) is a pi conjugate bridge, and 1, 3-indandione is used as the electron withdrawing end A '.

CS8 has the general structural formula of formula ii:

wherein R is 2-octyl dodecyl, R₁Is n-octyl, A' is 1, 3-indandione, and the specific chemical structural formula of the small molecule CS8 is shown as follows:

a preparation method of CS8 according to this embodiment, the synthetic route is shown in fig. 2, and the specific preparation method includes the following steps:

(1) synthesis of Compound 4(4, 10-bis (2-octyldodecyl) -4, 10-dihydrothieno [2',3':5,6] pyrido [3,4-g ] thieno [3,2-c ] isoquinoline-5, 11-dione): same as in example 1.

(2) Synthesis of 4, 10-bis (2-octyldodecyl) -2, 8-bis (trimethylstannyl) -4, 10-dihydrothieno [2',3':5,6] pyrido [3,4-g ] thieno [3,2-c ] isoquinoline-5, 11-dione (intermediate M2):

2.1 under argon atmosphere, 0.95g of Compound 4(1.07mmol) and 60mL of tetrahydrofuran were added to a 250mL three-necked flask, the temperature was lowered to-78 ℃, 1.16mL of lithium diisopropylamide (2.35mmol) was slowly added dropwise to the three-necked flask, and the reaction was allowed to proceed for 2 hours while maintaining the temperature.

2.2, adding trimethyl tin chloride into the reaction bottle, raising the temperature to room temperature, and reacting overnight.

And 2.3, adding water to quench the reaction, extracting with diethyl ether, drying an organic phase with anhydrous magnesium sulfate, filtering, and removing the solvent by spinning to obtain a crude product.

2.4 recrystallization of the crude product from isopropanol gives 1.17g of a yellow solid, intermediate M2, in 90% yield.

Hydrogen nuclear magnetic resonance spectroscopy:¹H NMR(400MHz,CDCl₃,δ/ppm):8.88(s,2H),7.10(s,2H),4.26(s,4H),2.05(s,2H),1.57(s,6H),1.30(d,J＝64.6Hz,58H),0.85(dd,J＝11.6,6.7Hz,12H),0.59-0.34(m,18H)。

nuclear magnetic resonance carbon spectrum:¹³C NMR(100MHz,CDCl₃,δ/ppm):161.79,140.72,140.20,129.64,126.33,124.67,123.96,123.34,77.32,77.20,77.00,76.68,49.50,37.21,31.89,31.89,31.77,30.00,29.62,29.56,29.33,29.29,26.75,22.66,14.09。

mass spectrum: MS (MALDI-TOF, m/z) C₆₂H₁₀₄N₂O₂S₂Sn₂: theoretical value 1218.019; found 1217.605.

As can be seen from the above, the compound has a correct structure and is an intermediate 4, 10-bis (2-octyldodecyl) -2, 8-bis (trimethylstannyl) -4, 10-dihydrothieno [2',3':5,6] pyrido [3,4-g ] thieno [3,2-c ] isoquinoline-5, 11-dione (intermediate M2).

(3) Synthesis of 2- ((5 "-bromo-3, 3" -dioctyl- [2,2':5',2 "-trithiophene ] -5-yl) methylene) -1H-indene-1, 3(2H) -dione (intermediate M3).

3.1 in a 50mL two-necked flask under argon atmosphere, 0.5g of Compound 7(5 ' -bromo-3, 3' -dioctyl- [2,2':5', 2' -trithiophene ] -5-aldehyde, commercially available) (0.86mmol), 0.25g of 1, 3-indanedione (1.72mmol) and 25mL of chloroform were added, 1mL of piperidine was slowly added dropwise to the flask at room temperature, and after the addition was completed, the temperature was raised to 70 ℃ for reaction overnight.

And 3.2, cooling to room temperature, adding water to quench the reaction, extracting with dichloromethane, washing with water, drying with anhydrous magnesium sulfate, and filtering to obtain a crude product.

3.3, separating and purifying the crude product by column chromatography (eluent: petroleum ether: dichloromethane: 1) to obtain a coffee solid of 438mg with a yield of 72%.

Hydrogen nuclear magnetic resonance spectroscopy:¹H NMR(400MHz,CDCl₃,δ/ppm):7.97(dd,J＝8.1,3.5Hz,2H),7.89(s,1H),7.79(dd,J＝13.3,9.3Hz,3H),7.37(d,J＝3.9Hz,1H),7.08(d,J＝3.9Hz,1H),6.93(s,1H),2.90-2.79(m,2H),2.79-2.67(m,2H),1.66-1.55(m,10H),1.28(s,14H),0.92-0.83(m,6H)。

from the above, the compound has a correct structure and is intermediate 2- ((5 ' -bromo-3, 3' -dioctyl- [2,2':5', 2' -trithiophene ] -5-yl) methylene) -1H-indene-1, 3(2H) -dione (intermediate M3).

(4) Synthesis of small molecule CS8

4.1 in a 50mL two-necked flask, under argon atmosphere, 0.38g of intermediate M2(0.32mmol), 0.5g of 2- ((5 ' -bromo-3, 3' -dioctyl- [2,2':5', 2' -trithiophene) were added in that order]-5-yl) methylene) -1H-indene-1, 3(2H) -dione (0.70mmol), 10mg, Pd (PPh)₃)₄(0.0087mmol) and 20mL of dry toluene. The reaction was evacuated with a stream of argon for 30 minutes and refluxed at 120 ℃ for 48 hours.

4.2, after the reaction is cooled, extracting by using trichloromethane, washing by using saturated saline solution, drying by using anhydrous magnesium sulfate, and filtering to obtain a crude product.

4.3, separating and purifying the crude product by column chromatography (eluent: petroleum ether: trichloromethane: 1: 3) to obtain 148mg of cyan solid with a yield of 24%.

Hydrogen nuclear magnetic resonance spectroscopy:¹H NMR(400MHz,CDCl₃,δ/ppm):8.80(s,2H),8.00-7.92(m,4H),7.89(s,2H),7.84(s,2H),7.80-7.78(m,2H),7.52(s,2H),7.42(d,J＝3.5Hz,2H),7.16(s,2H),7.13-7.09(m,2H),7.00(s,2H),4.26-4.23(m,4H),2.87-2.82(m,8H),1.74-1.70(m,6H),1.56-1.52(m,108H),1.32-1.17(m,24H)。

mass spectrum: MS (MALDI-TOF, m/z) C₁₃₂H₁₇₂N₂O₆S₈Theoretical value 2139.320; found 2138.174.

As can be seen from the above, the product has a correct structure and is a TPTI-based small molecule CS8 shown in a structural formula (2), wherein R is 2-octyldodecyl, and R is₁Is n-octyl and A' is 1, 3-indandione.

The micromolecule CS8 of the embodiment is applied to preparing an organic solar cell, the micromolecule CS8 prepared in the embodiment is used as a donor material in the organic solar cell and is used for constructing a bulk heterojunction type organic solar cell together with an acceptor phase material, the structure of the cell is shown in figure 5 and is ITO/PEDOT: PSS/photoactive layer/Ca/Al, and the photoactive layer is formed by micromolecules CS8 and PC shown in structural formula I₇₁BM blending.

The preparation method of the solar cell comprises the following steps:

(1) the anode is made of Indium Tin Oxide (ITO) conductive glass, an anode modification layer PEDOT/PSS polymer conductive film is coated on the ITO conductive glass in a spin mode, and the ITO conductive glass is processed for 15 minutes at the temperature of 150 ℃.

(2) Spin coating a layer of small molecule CS8 and receptor material PC₇₁BM blend (CS 8: PC)₇₁BM weight ratio of 1: 1, which can be implemented at a weight ratio of 1: 0.5-2).

(3) After drying for half an hour, metal calcium (about 20nm) is evaporated in vacuum to be used as a cathode modification layer.

(4) Finally, cathode metallic aluminum (about 100nm) is evaporated, and the area of the plated metal (about 4 mm) is controlled by a mask²)。

The photovoltaic performance of the organic solar cell is under simulated sunlight (AM1.5G, 100 mW/cm)²) Testing was performed by Keithley2602 table source, etc.

Example 4:

a '-pi-A' type small molecule CS9 based on TPTI unit: the TPTI unit with weak electron withdrawing property is used as the central core A, 3, 3' -dioctyl- (2,2':5', 2' -trithiophene) is a pi conjugate bridge, and 3-ethyl rhodanine is used as the electron withdrawing end A '.

CS9 has the general structural formula of formula ii:

wherein R is 2-octyl dodecyl, R₁Is n-octyl, A' is 3-ethyl rhodanine, and the specific chemical structural formula of the small molecule CS9 is shown as follows:

a preparation method of CS9 according to this embodiment, the synthetic route is shown in fig. 2, and the specific preparation method includes the following steps:

(1) synthesis of (E) -5- ((5 "-bromo-3, 3" -dioctyl- [2,2':5',2 "-trithiophene ] -5-yl) methylene) -3-ethyl-2-rhodanin-4-one:

1.1 in a 50mL two-necked flask under an argon atmosphere, 0.5g of Compound 7(0.86mmol), 0.28g of 3-ethylrhodanine (1.72mmol), and 25mL of chloroform were added, and 1mL of piperidine was slowly added dropwise to the three-necked flask at room temperature, and after the addition, the temperature was raised to 70 ℃ to react overnight.

1.2, cooling to room temperature, adding water to quench the reaction, extracting with dichloromethane, washing with water, drying with anhydrous magnesium sulfate, and filtering to obtain a crude product.

1.3, the crude product was purified by column chromatography (eluent: petroleum ether: dichloromethane: 2: 1) to yield 448mg of a coffee solid in 78% yield.

Hydrogen nuclear magnetic resonance spectroscopy:¹H NMR(400MHz,CDCl₃,δ/ppm)：7.79(s,1H),7.23(s,1H),7.20(d,J＝3.8Hz,1H),7.05(d,J＝3.8Hz,1H),6.92(s,1H),4.19(q,J＝7.3Hz,3H),2.84-2.76(m,3H),2.76-2.69(m,2H),1.71-1.50(m,10H),1.31(dd,J＝22.6,15.5Hz,14H),0.87(dd,J＝7.0,3.4Hz,6H)。

as can be seen from the above, the compound has a correct structure and is an intermediate (E) -5- ((5 ' -bromo-3, 3' -dioctyl- [2,2':5', 2' -trithiophene ] -5-yl) methylene) -3-ethyl-2-rhodanin-4-one.

(2) Preparation of intermediate M2: same as in example 1.

(3) Synthesis of small molecule CS 9:

synthesis of Small molecule CS9 starting from intermediate M2(0.35g,0.29mmol) and (E) -5- ((5 "-bromo-3, 3" -dioctyl- [2,2':5',2 "-trithiophene ] -5-yl) methylene) -3-ethyl-2-rhodanin-4-one (0.5g,0.69 mmol). Synthesized in a similar manner to small molecule CS8, the crude product was purified by column chromatography (eluent: petroleum ether/chloroform 1/1) to yield a dark brown solid 0.12g with 19% yield.

Hydrogen nuclear magnetic resonance spectroscopy:¹H NMR(400MHz,CDCl₃,δ/ppm)：8.70(s,2H),7.76(s,2H),7.23-7.17(m,4H),7.15-7.08(m,4H),7.10-7.01(m,2H),4.29-4.11(m,8H),2.85-2.82(m,8H),2.03(s,6H),1.69-1.20(m,110H),0.89-0.85(m,30H).

mass spectrum: MS (MALDI-TOF, m/z) C₁₂₄H₁₇₄N₄O₄S₁₂: theory of thingsTheoretical value 2169.501; found 2168.010.

The micromolecule CS9 of the embodiment is applied to preparing an organic solar cell, the micromolecule CS9 prepared in the embodiment is used as a donor material in the organic solar cell and is used for constructing a bulk heterojunction type organic solar cell together with an acceptor phase material, the structure of the cell is shown in figure 5 and is ITO/PEDOT: PSS/photoactive layer/Ca/Al, and the photoactive layer is formed by micromolecules CS9 and PC shown in structural formula I₇₁BM blending.

The preparation method of the solar cell comprises the following steps:

(1) the anode is made of Indium Tin Oxide (ITO) conductive glass, an anode modification layer PEDOT/PSS polymer conductive film is coated on the ITO conductive glass in a spin mode, and the ITO conductive glass is processed for 15 minutes at the temperature of 150 ℃.

(2) Spin coating a layer of small molecule CS9 and receptor material PC₇₁BM blending (CS 9: PC)₇₁BM weight ratio of 1: 1, which can be implemented at a weight ratio of 1: 0.5-2).

(3) After drying for half an hour, metal calcium (about 20nm) is evaporated in vacuum to be used as a cathode modification layer.

(4) Finally, cathode metallic aluminum (about 100nm) is evaporated, and the area of the plated metal (about 4 mm) is controlled by a mask²)。

The photovoltaic performance of the organic solar cell is under simulated sunlight (AM1.5G, 100 mW/cm)²) Testing was performed by Keithley2602 table source, etc.

Experimental example:

the spectral, electrochemical and photovoltaic properties were determined as follows:

(1) spectral properties of the small molecules CS6, CS7, CS8 and CS9

FIG. 3 shows UV-VIS absorption spectra of small molecule CS6, CS7, CS8, and CS9 films on quartz slides. According to the ultraviolet-visible absorption spectrum, the peak values of the maximum absorption side bands (lambda) of the small molecules CS6, CS7, CS8 and CS9 on the quartz plate are 719nm, 711nm, 860nm and 724nm respectively. According to empirical formula E_g ^optThe corresponding optical band gaps of the polymer were calculated to be 1.72, 1.74, 1.61, 1.71eV, 1240/λ, respectively.

(2) Electrochemical properties of small molecules CS6, CS7, CS8 and CS9

FIG. 4 is a cyclic voltammogram of small molecules CS6, CS7, CS8, and CS 9. And (3) testing by adopting a three-electrode system: the working electrode is a platinum electrode coated with films of small molecules CS6, CS7, CS8 and CS9 in a knife coating manner, a platinum wire is a counter electrode, Ag/AgCl is a reference electrode, and Bu₄NPF₆As a supporting electrolyte, ferrocene redox couple is used as an internal standard. The test conditions were: the scanning range is-1.6V (vs. Ag/AgCl), and the scanning speed is 100 mV/s.

The HOMO/LUMO energy levels of the four small molecules are respectively-5.87/-3.57 eV, -5.70/-3.57eV, -5.53/-3.56eV and-5.38/-3.65 eV calculated according to the cyclic voltammogram. Since the small molecule TPTI unit in this embodiment has an electron-withdrawing capability, the HOMO levels of the four small molecules in this embodiment are relatively low.

(3) Photovoltaic properties of organic small molecule solar cells of small molecules CS6, CS7, CS8 and CS9

The prepared micromolecules can be used as donor materials in organic micromolecule solar cells to construct bulk heterojunction type organic solar cells together with acceptor phase materials, the structure of the organic solar cells is ITO/PEDOT: PSS/photoactive layer/Ca/Al, as shown in figure 5, the photoactive layer is formed by any one of micromolecules in examples 1 to 4 and PC₇₁BM blending. Wherein the reference numbers of figure 5 are: a-base anode, b-anode modifying layer, c-mixed active layer of donor material and acceptor material, d-cathode modifying layer and e-cathode.

In the organic micromolecule bulk heterojunction type solar cell, Indium Tin Oxide (ITO) is adopted as an anode, an anode modification layer PEDOT (PSS) polymer conductive film is coated on the ITO in a spinning mode, the PSS polymer conductive film is processed for 15 minutes at 150 ℃, and then a layer of prepared micromolecules and receptor material PC are coated in a spinning mode₇₁Drying for half an hour, vacuum evaporating to obtain metal calcium (about 20nm) as cathode modification layer, evaporating to obtain cathode aluminum (about 100nm), and controlling the area of plated metal (about 4 mm) by mask²). The photovoltaic performance of the organic micromolecule solar cell device is under simulated sunlight (AM1.5G, 100 mW/cm)²) Tong (Chinese character of 'tong')The tests were performed by Keithley2602 Table Source, etc.

Fig. 6 is a current-voltage characteristic (J-V) curve for an organic small molecule solar cell prepared based on four small molecules. The optimal photovoltaic performance of the photovoltaic device corresponding to the graph is as follows:

CS 6: energy conversion efficiency (PCE) — 3.82%, open circuit voltage (V)_oc) 1.04V, short-circuit current (J)_sc)＝7.04mA/cm²The Fill Factor (FF) is 52.17%.

CS 7: energy conversion efficiency (PCE) — 1.47%, open circuit voltage (V)_oc) 0.92V, short-circuit current (J)_sc)＝3.23mA/cm²The Fill Factor (FF) is 48.58%.

CS 8: energy conversion efficiency (PCE) — 0.53%, open circuit voltage (V)_oc) 0.63V, short-circuit current (J)_sc)＝2.67mA/cm²The Fill Factor (FF) is 33.06%.

CS 9: energy conversion efficiency (PCE) — 0.54%, open circuit voltage (V)_oc) 0.86V, short-circuit current (J)_sc)＝1.89mA/cm²The Fill Factor (FF) is 33.02%.

The invention takes synthesized micromolecules containing different pi conjugate bridges and terminal units based on TPTI as organic semiconductor active layers to prepare a plurality of organic micromolecule solar cell devices. The highest energy conversion efficiency reaches 3.82%, the open-circuit voltage is as high as 1.04V, and the filling factor reaches 52.17%. All experimental results show that the TPTI-based micromolecules provided by the invention are excellent micromolecule semiconductor materials and show potential application values in the aspect of organic solar cells. The invention not only has simple and effective synthesis method, but also prepares a series of A '-pi-A' type micromolecular materials based on TPTI. The method has very important significance for researching the relationship between the structure and the performance of the micromolecular semiconductor material, and can further guide the development of the micromolecular semiconductor material with high photoelectric performance.

The foregoing is merely a preferred embodiment of the invention and is not intended to limit the invention in any manner. Although the present invention has been described with reference to the preferred embodiments, it is not intended to be limited thereto. Those skilled in the art can make many possible variations and modifications to the disclosed embodiments, or equivalent modifications, without departing from the spirit and scope of the invention, using the methods and techniques disclosed above. Therefore, any simple modification, equivalent replacement, equivalent change and modification made to the above embodiments according to the technical essence of the present invention are still within the scope of the protection of the technical solution of the present invention.

Claims (10)

1. An A '-pi-A' type organic small molecule, wherein the A '-pi-A' type organic small molecule has a structural formula of formula I:

in the formula I: r is selected from any one of the following groups:

R₁any one selected from the following groups: -C₆H₁₃、-C₈H₁₇、-C₁₂H₂₅、-C₁₆H₃₃、

A' is selected from any one of the following groups:

and when R is

When radical, R₁Is not-C₆H₁₃A group; a' is not

A group.

2. The preparation method of the A ' -pi-A ' type organic micromolecule as claimed in claim 1, wherein the A ' -pi-A ' type organic micromolecule is obtained by performing a Knoevenagel condensation reaction on an intermediate M1 and a compound containing an A ' group under the action of a solvent and a catalyst, and the intermediate M1 has a structural formula shown in the following formula III:

in the formula III: r is selected from any one of the following groups:

R₁any one selected from the following groups: -C₆H₁₃、-C₈H₁₇、-C₁₂H₂₅、-C₁₆H₃₃、

The A 'group in the compound containing the A' group is selected from any one of the following groups:

3. the preparation method according to claim 2, wherein the molar ratio of the intermediate M1 to the compound containing an A' group is 1: 3-4;

and/or the molar ratio of the catalyst to the intermediate M1 is 15-22: 1;

and/or the catalyst is one of pyridine, piperidine and triethylamine;

and/or the solvent is one of trichloromethane and acetonitrile.

4. The preparation method according to claim 2 or 3, wherein the intermediate M1 is prepared by the following method:

s1-1, reacting the compound 1 with the compound 2 to obtain a compound 3;

s1-2, heating and reacting the compound 3, palladium acetate, cesium carbonate, tricyclohexyl phosphorus fluoborate and N, N-dimethylacetamide to obtain a compound 4;

s1-3, carrying out a light-resistant reaction on the compound 4 and bromosuccinimide to obtain a compound 5;

s1-4, mixing the compound 5, a 3-alkylthiophene tin reagent and tetratriphenylphosphine palladium, and heating to react to obtain a compound 6;

s1-5, reacting compound 6, N-dimethylacetamide and POCl₃Reacting to obtain an intermediate M1;

the compound 1 is

The compound 2 is

The compound 3 is:

the compound 4 is:

the compound 5 is:

the compound 6 is:

5. the preparation method according to claim 4, wherein in S1-1, the molar ratio of compound 1 to compound 2 is 2-3: 1;

and/or in S1-2, the molar ratio of the compound 3 to the palladium acetate to the cesium carbonate to the tricyclohexyl phosphorus fluoroborate is 1: 0.6-0.8: 12-16: 1-2;

and/or in the S1-3, the molar ratio of the compound 4 to bromosuccinimide is 1: 2-3;

and/or in the S1-4, the molar ratio of the compound 5, the 3-alkylthiophene tin and the tetratriphenylphosphonium palladium is 1: 3-4: 0.04-0.06;

and/or, in the S1-5, the compound 6, N-dimethylacetamide and POCl₃The molar ratio of (A) to (B) is 1: 2-3: 3-5.

6. An a '-pi-a' type organic small molecule, wherein the a '-pi-a' type organic small molecule has a structural formula of formula II:

in the formula II: r is selected from any one of the following groups:

R₁any one selected from the following groups: -C₆H₁₃、-C₈H₁₇、-C₁₂H₂₅、-C₁₆H₃₃、

A' is selected from any one of the following groups:

7. the preparation method of the A '-pi-A' type organic micromolecule according to claim 6, characterized in that the A '-pi-A' type organic micromolecule is obtained by performing Stille coupling reaction on an intermediate M2 and an intermediate M3 under the action of a solvent and a catalyst;

the intermediate M2 has the following structural formula shown in IV:

the intermediate M3 has the following structural formula V:

8. the preparation method of claim 7, wherein the intermediate M2 is prepared by the following method:

s2-1, reacting the compound 4, tetrahydrofuran and lithium diisopropylamide at-78 ℃,

s2-2, adding trimethyl tin chloride continuously to react at room temperature to obtain an intermediate M2,

the compound 4 is:

and/or the intermediate M3 is prepared by adopting the following method:

s3-1, heating and reacting the compound 7 and A' under the action of a solvent and a catalyst to obtain a compound M3;

the compound 7 is

9. The method according to claim 8, wherein the catalyst is tetrakistriphenylphosphine palladium;

and/or the solvent is toluene or chlorobenzene;

and/or the molar ratio of the intermediate M2 to the intermediate M3 is 1: 2-3;

and/or the molar ratio of the catalyst to the intermediate M2 is 0.02-0.05: 1;

and/or in S2-2, the molar ratio of the compound 4, lithium diisopropylamide and trimethyltin chloride is 1: 2-3: 3-5;

and/or in S3-1, the molar ratio of the compound 7 to A' is 1: 2-4.

10. The use of a small organic molecule of the a '-pi-a' type according to claim 1 or claim 6 for the preparation of a solar cell, characterized in that the application method is:

(1) spin-coating a conductive film of PEDOT/PSS polymer on the anode;

(2) spin-coating an optically active layer formed by blending A '-pi-A' type organic micromolecules and PC71 BM;

(3) vacuum evaporating metal calcium as a cathode modification layer;

(4) and evaporating cathode metal aluminum to obtain the solar cell.

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