A-π-D-π-A type corrole donor photovoltaic material and preparation method and application thereof

Abstract

The present invention discloses a preparation method and application of A‑π‑D‑π‑A type corrole donor photovoltaic materials. The A‑π‑D‑π‑A type corrole donor photovoltaic material uses the corrole ring as the central electron-donating unit, pyrrolopyrrole diketo as the electron-withdrawing unit, and is connected to the corrole through a π bridge, thereby forming an A‑π‑D‑π‑A type, forming a push-pull electron effect, and can effectively play the role of electron transmission. The present invention adopts an A‑π‑D‑π‑A type structure as a donor part, which can adjust its LUMO energy level so that the exciton can be better dissociated, and at the same time, the large conjugated main structure enhances the light absorption ability of the photovoltaic material, which can play the role of effectively transferring charges. In addition, the synthesis steps of the A‑π‑D‑π‑A type corrole donor photovoltaic material are explored, which also provides direction for optimizing and developing corrole small molecule donor materials, and has important application prospects in solar cells.

Description

Technical Field

[0001] The invention belongs to the field of organic small molecule photovoltaic materials, and specifically relates to A-π-D-π-A type corrole donor photovoltaic materials and preparation methods and applications thereof. Background Art

[0002] Organic solar cell technology uses organic materials as active layers to convert solar energy into electrical energy. It also has the advantages of light weight, flexibility, solution processing, and low material cost. Therefore, it has attracted widespread attention from academia and the business community. At present, the efficiency of devices based on polymers as donor materials under laboratory conditions has exceeded 20%, but the problems of batch differences in polymer materials have limited its development to a certain extent. The characteristics of small molecule donor materials such as fixed structure, easy regulation of spectral absorption and energy levels, and small batch differences have attracted the interest of many researchers. In recent years, organic solar cells based on small molecule donor materials have developed rapidly, and the energy conversion efficiency of devices has exceeded 17%. However, there is still a long way to go to achieve large-scale commercial production, among which the stability of materials and devices is an important obstacle to the development of organic solar cells. For small molecule donors, materials such as polythiophenes, benzodithiophenes, triethylamines, and porphyrins have been developed for the selection of materials, but the stability of the materials is not high, the efficiency needs to be improved, and new materials still need to be developed.

[0003] As a derivative of porphyrin, corrole, like porphyrin, also has a large π conjugated system, high molar absorption coefficient, good planarity, and multiple chemical sites for modification. Therefore, it also has the potential to be used as an electron-donating unit in small molecule battery materials. For small molecule donor materials, the A-π-D-π-A type (acceptor unit-π bridge-donor unit-π bridge-acceptor unit) structure can extend the conjugated system, promote the intermolecular π-π stacking, and enhance the intramolecular charge transfer, thereby reducing the optical band gap. It is a better structural type in small molecule donor materials. However, no research progress has been found on the A-π-D-π-A type corrole small molecule solar cell materials.

[0004] In summary, it is of great significance to study how to synthesize A-π-D-π-A type corrole small molecule donor materials. After many attempts, we found a method for preparing A-π-D-π-A type corrole small molecule donor materials. Summary of the invention

[0005] In order to solve the shortcomings and deficiencies of the prior art, the primary purpose of the present invention is to provide an A-π-D-π-A type corrole donor photovoltaic material.

[0006] The corrole and the small molecule receptor of the present invention are bonded by chemical bonds to form an organic small molecule donor battery material, wherein the corrole unit with a large π conjugated plane is used as the donor part of the small molecule, and the electron-withdrawing unit connected by a triple bond is used as the receptor part of the small molecule, forming an A-π-D-π-A type structure. The structure effectively adjusts the absorption spectrum of the material and improves the carrier mobility of the material; at the same time, by changing the electron-withdrawing ability of the electron-withdrawing group, the HOMO and LUMO energy levels of the molecule are effectively adjusted. By using the corrole material of this structure, the purpose of optimizing the photoelectric conversion efficiency of the device can be achieved.

[0007] Another object of the present invention is to provide a method for preparing the above-mentioned A-π-D-π-A type corrole donor photovoltaic material.

[0008] Another object of the present invention is to provide application of the above-mentioned A-π-D-π-A type corrole donor photovoltaic material.

[0009] The purpose of the present invention is achieved through the following technical solutions:

[0010] An A-π-D-π-A type corrole donor photovoltaic material having the following chemical structure:

[0011]

[0012] Wherein, each A is the same as or different from each other and independently represents an electron-withdrawing group having a conjugated structure; Ar represents one of hydrogen, an alkyl group, an alkoxy group, a substituted or unsubstituted aromatic group; and M represents a metal element or three hydrogen elements.

[0013] Preferably, Ar is one of the following structures:

[0014]

[0015] Wherein, R1 and R2 are alkyl or alkoxy groups having a carbon number of 0-20, and when the carbon number is 0, R1 and R2 are hydrogen or hydroxyl groups.

[0016] Preferably, A is one of the following structural units:

[0017]

[0018] Wherein, R1 and R2 are alkyl or alkoxy groups having a carbon number of 0-20, and when the carbon number is 0, R1 and R2 are hydrogen or hydroxyl groups.

[0019] Another object of the present invention is to provide a method for preparing the A-π-D-π-A type corrole donor photovoltaic material, comprising the following steps:

[0020] (1) Under the protection of an inert gas and in the presence of an acid catalyst, 5-iodo-2-thiophenecarboxaldehyde and pyrrole are reacted in a light-proof condition to form compound A after purification:

[0021]

[0022] (2) Under the protection of an inert gas, compound A and Ar-CHO are dissolved in a mixed solvent under light-proof conditions, reacted for 2±0.5 hours under the action of an acid catalyst, extracted, and an oxidant is added to react for 30±10 minutes, and compound B is formed after purification:

[0023]

[0024] (3) Under the protection of an inert gas, A-Br and triisopropylsilyl acetylene are heated in the presence of a mixed solvent and a catalyst to undergo a Sonogashira coupling reaction, and after purification, compound C is formed:

[0025]

[0026] (4) removing the protecting group from compound C to obtain an intermediate product, and heating the intermediate product and compound B in a mixed solvent and a catalyst under the protection of an inert gas to carry out a Sonogashira coupling reaction, and obtaining the A-π-D-π-A type corrole donor photovoltaic material (compound D) after purification:

[0027]

[0028] (5) Dissolving the metal salt and compound D in a mixed solvent at room temperature, reacting in the dark, and obtaining the A-π-D-π-A type corrole donor photovoltaic material after purification:

[0029] Here, M represents a metal element.

[0030] Preferably, the acid catalyst in step (1) is trifluoroacetic acid, and the amount used is 0.1 to 0.2 times the amount of 5-iodo-2-thiophenecarboxaldehyde; and the reaction time is 10±5 minutes.

[0031] Preferably, the mixed solvent in step (2) is water / methanol, and the volume ratio is 1:1 to 1:2; the concentration of Ar-CHO is 4 to 6 mmol / L; the acid catalyst in step (2) is concentrated hydrochloric acid with a mass fraction of 36 to 38%, and the amount used is 0.02 to 0.04 times the volume of the water / methanol mixed solvent, and the reaction temperature is 20 to 30°C;

[0032] The extractant in step (2) is dichloromethane, and the oxidant is 2,3-dichloro-5,6-dicyano-1,4-benzoquinone.

[0033] Preferably, the mixed solvent in step (3) is tetrahydrofuran / triethylamine, with a volume ratio of 2:1 to 10:1; the catalysts used are bis(triphenylphosphine)palladium dichloride and cuprous iodide, with the amounts of both being 0.1 to 0.2 times the amount of A-Br substance, and the reaction temperature is 60 to 80°C.

[0034] Preferably, the structure of the intermediate product in step (4) is: The mixed solvent is tetrahydrofuran / triethylamine, and the volume ratio is 2:1-10:1; the catalysts used are tri(dibenzylideneacetone)dipalladium and triphenylphosphine, and the amounts used are 0.2 times and 2 times the amount of compound B, respectively; the reaction temperature is 60-80°C, and the reaction time is 12±4 hours.

[0035] Preferably, the metal salt in step (5) is copper acetate, the mixed solvent is dichloromethane / methanol, the volume ratio is 1:1, the reaction temperature is 20-30° C., and the reaction time is 3±1 hours.

[0036] Another object of the present invention is to provide an application of the A-π-D-π-A type corrole donor photovoltaic material. Preferably, the A-π-D-π-A type corrole donor photovoltaic material is used as a donor material for an organic solar cell.

[0037] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0038] (1) The A-π-D-π-A type corrole small molecule donor material designed by the present invention has the corrole ring as the central electron-donating unit, pyrrolopyrrole diketo as the electron-withdrawing unit, and is connected to the corrole through a π bridge, thereby forming an A-π-D-π-A type, forming a push-pull electron effect, which can effectively play the role of electron transmission. Using a π bridge to connect the electron-withdrawing unit at the two meso positions of the corrole can effectively increase the π conjugated system and intramolecular charge transfer (ICT) of the molecule, and effectively broaden the ultraviolet absorption spectrum (UV-vis) of the material.

[0039] (2) The present invention adopts the A-π-D-π-A structure as the donor part, which can adjust its LUMO energy level so that the exciton can be better dissociated. At the same time, the large conjugated main structure enhances the light absorption ability of the photovoltaic material and can effectively transfer charges. And by introducing metal elements into the corrole cavity, the HUMO and LUMO energy levels of the battery donor part can be effectively adjusted, thereby designing an organic solar cell material with a better matching energy level between the donor material and the acceptor material.

[0040] (3) The A-π-D-π-A type corrole small molecule donor material designed in the present invention can provide a new design idea for the selection of electron donating units in organic solar cells, and explore a practical method for synthesizing this type of corrole donor material, laying the foundation for future research, industrial production and commercial application. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 The UV-visible absorption spectra of the solutions obtained in Example 5 and Example 6 are shown in FIG.

[0042] Figure 2 The UV-visible absorption spectra of the films obtained in Example 5 and Example 6 are shown in FIG.

[0043] Figure 3 The photovoltaic cells prepared from the materials obtained in Example 5 and Example 6 were subjected to the conditions of AM 1.5 and 100 mW / cm 2 Current-voltage curve under illumination. DETAILED DESCRIPTION

[0044] The present invention is further described in detail below in conjunction with examples and drawings, but the embodiments of the present invention are not limited thereto.

[0045] If no specific conditions are specified in the examples of the present invention, the experiments were carried out under conventional conditions or conditions recommended by the manufacturer. All raw materials, reagents, etc., whose manufacturers are not specified, are conventional products that can be purchased commercially.

[0046] Example 1

[0047] Synthesis of compound 2:

[0048] The reaction equation is as follows:

[0049]

[0050] Under Ar atmosphere, compound 1 (508 mg, 2.134 mmol) and pyrrole (6.5 mL, 95 mmol) were added to a 50 mL double-necked flask, trifluoroacetic acid (15 μL, 0.21 mmol, dissolved in 5 mL dichloromethane) was added to the reaction system, and the reaction was carried out for 10 min in the dark. Triethylamine was then added to stop the reaction. Pyrrole was removed by vacuum distillation, and PE:DCM:EA=8:1:1 was used as the eluent to pass through a silica gel column. 522.4 mg of dark yellow solid was obtained with a yield of 69%.

[0051] 1H NMR (400MHz, DMSO-d6) δ10.63(s,2H),7.10(d,J=3.6Hz,1H),6.61(q,J=2.5Hz,2 H),6.43(d,J=4.3Hz,1H),5.90(q,J=2.7Hz,2H),5.82–5.75(m,2H),5.57(s,1H).

[0052] Example 2

[0053] Synthesis of compound 4:

[0054] The reaction equation is as follows:

[0055]

[0056] Under Ar atmosphere, compound 2 (678.2 mg, 1.965 mmol) and compound 3 (159.4 mg, 0.9823 mmol) were added to a 250 mL two-necked bottle, dissolved in a methanol / water mixed solvent (92 mL: 86 mL), stirred for 15 min, and 5.2 mL of 36% concentrated hydrochloric acid was slowly added to the two-necked bottle. The reaction was protected from light for 90 min. The reaction solution was extracted with 150 mL of dichloromethane, dried and transferred to a 250 mL two-necked bottle, 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) (446.0 mg, 1.965 mmol) was added, stirred for 30 min, and the reaction was terminated. The column was dry-packed with 200-300 mesh silica gel powder, and the reaction solution was directly poured into the silica gel column for column chromatography, using dichloromethane as the eluent. Then tetrahydrofuran was used as the eluent to pass the GPC column. Recrystallization was performed using methanol / chloroform to obtain 173.1 mg of a dark green solid with a yield of 21%.

[0057] 1 H NMR (400MHz, CF3COOD) δ7.65(d,J=4.1Hz,2H),7.58(d,J=3.9Hz,2H),7.50(s,2H),7.42(d,J=7. 8Hz,2H),7.32(s,2H),7.18(s,2H),7.09(d,J=7.4Hz,2H),6.61(s,2H),1.24(s,9H).MALDI-TOF m / z:calcd.for[C 37 H 28 I2N4S2]:845.98; found:846.05.

[0058] Example 3

[0059] Synthesis of compound 6:

[0060] The reaction equation is as follows:

[0061]

[0062] Under Ar atmosphere, 2,5-di(2-ethylhexyl)-3,6-di(2'-thienyl)-pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione (Compound 5) (154.6 mg, 0.2561 mmol) was added to a 50 mL two-necked bottle, 10 mL of tetrahydrofuran and 2 mL of triethylamine were added, and the mixture was stirred for 30 min. Bis(triphenylphosphine)palladium dichloride (Pd(PPh3)2Cl2) (17.9 mg, 0.02561 mmol) and cuprous iodide (CuI) (4.7 mg, 0.02561 mmol) were added to the bottle, and the mixture was ventilated for 15 min. Triisopropylsilyl acetylene (500.0 mg, 2.741 mmol) was added to the bottle with a syringe, and the mixture was heated to 65°C overnight. After the solvent was removed by rotary evaporation, the residue was passed through a silica gel column using PE:DCM=3:1 as the eluent to obtain 165.4 mg of a dark red solid with a yield of 91%.

[0063] 1 H NMR(500MHz,Chloroform-d)δ9.65(d,J=4.6Hz,4H),8.99(d,J=4.6Hz,4H),6.75(s,2H) ,2.72(d,J=6.7Hz,4H),1.70(s,2H),1.52–1.29(m,23H),0.97(dt,J=19.5,7.0Hz,12H).

[0064] Example 4

[0065] Synthesis of compound 7:

[0066] The reaction equation is as follows:

[0067]

[0068] Compound 6 (165.4 mg, 0.2346 mmol) was added to a 50 mL single-mouth bottle, dissolved with 5 mL of tetrahydrofuran, and tetrabutylammonium fluoride (1 M, 0.35 mL, 0.35 mmol) was slowly added dropwise, and the reaction was continued for 10 min. The mixture was extracted with dichloromethane, and the solvent was removed by rotary evaporation. The mixture was directly subjected to the next step of reaction without further purification.

[0069] Example 5

[0070] Synthesis of compound 8:

[0071] The reaction equation is as follows:

[0072]

[0073] Under Ar atmosphere, compound 7 (128.7 mg, 0.2346 mmol) and compound 4 (50.0 mg, 0.05906 mmol) were added to a 50 mL double-necked bottle, dissolved with 10 mL of ultra-dry tetrahydrofuran and 1 mL of ultra-dry triethylamine, stirred for 30 min, and tri(dibenzylideneacetone)dipalladium (Pd2(dba)3) (8.6 mg, 0.01181 mmol) and triphenylphosphine (PPh3) (31.0 mg, 0.1181 mmol) were added, and stirring was continued for 15 min, and the temperature was raised to 70 ° C for reaction for 12 h. After the reaction was completed, it was cooled to room temperature, extracted with chloroform, and the solvent was removed by rotary evaporation. Chloroform was used as the eluent to pass through a silica gel column, and then tetrahydrofuran was used as the eluent to pass through a GPC column. Recrystallization was performed using methanol / chloroform to obtain 31.0 mg of a black solid with a yield of 31%.

[0074] MALDI-TOF m / z:calcd.for[C 101 H 106 N8O4S6]:1686.67; found:1688.66.

[0075] The corrole organic small molecule photovoltaic material prepared in this example was dissolved in chloroform solution, and its molar concentration was (10 -5 -10 -4 mol / L), the UV-visible absorption spectrum of the obtained chloroform solution is shown in Figure 1 Example 5 has a relatively broad absorption in chloroform solution, with three groups of peaks appearing, among which the highest absorption peak is located at 439 nm.

[0076] The corrole organic small molecule photovoltaic material prepared in this example was prepared into a thin film by spin coating, and the film thickness was about 100 nm. The ultraviolet-visible absorption spectrum of the thin film was shown in FIG. Figure 2 Example 5 has a relatively wide absorption in the film, with three groups of peaks, wherein the maximum absorption peak is located at 600 nm, the absorption band edge is at 842 nm, and the optical band gap is 1.47 eV, indicating that Example 5 has a relatively narrow band gap.

[0077] The heterojunction cell prepared by using the corrole organic small molecule photovoltaic material of this embodiment as a donor and Y6 as an acceptor has a device structure of: ITO / PEDOT:PSS / Example 5:Y6 / PDINO / Ag, and at AM 1.5, 100mW / cm 2 The current-voltage curve under light is shown in Figure 3 The photoelectric conversion efficiency of the prepared device is 0.035%, and the short-circuit current is 0.36 mA / cm 2 , the open circuit voltage is 0.39V and the fill factor is 25.92%.

[0078] Example 6

[0079] Synthesis of compound 9:

[0080] The reaction equation is as follows:

[0081]

[0082] Compound 8 (38.8 mg, 0.02298 mmol) was added to a 50 mL single-mouth bottle, and a mixed solvent of dichloromethane and methanol (10 mL:10 mL) was added and stirred for 15 min. Copper acetate (21.0 mg, 0.1149 mmol) was added to the single-mouth bottle and reacted for 3 h in the dark. The solvent was removed by rotary evaporation, and the silica gel column was passed using PE:DCM=1:1 as the eluent, and then tetrahydrofuran was used as the eluent for the GPC column. Recrystallization was performed using methanol / chloroform to obtain 26.3 mg of a dark green solid with a yield of 79%.

[0083] MALDI-TOF m / z:calcd.for[C 101 H 103 CuN8O4S6]:1746.57; found:1748.60.

[0084] The donor photovoltaic material prepared in this example was dissolved in a chloroform solution with a mass concentration of (10 -5 -10 - 4 mol / L), the UV-visible absorption spectrum of the obtained chloroform solution is shown in Figure 1 Example 6 has a relatively broad absorption in chloroform solution, with three groups of peaks, among which the highest absorption peak is located at 579 nm.

[0085] The donor photovoltaic material prepared in this example was prepared into a thin film by spin coating, and the film thickness was about 100 nm. The ultraviolet-visible absorption spectrum of the thin film was shown in FIG. Figure 2 Example 6 has a wide absorption in the film, with three groups of peaks, among which the maximum absorption peak is located at 600nm, the absorption band edge is at 792nm, and the optical band gap is 1.57eV, indicating that the introduction of metal can play a role in regulating the band gap of this type of material.

[0086] The heterojunction cell prepared by using the corrole organic small molecule photovoltaic material of this embodiment as a donor and Y6 as an acceptor has a device structure of: ITO / PEDOT:PSS / Example 6:Y6 / PDINO / Ag, and at AM 1.5, 100mW / cm 2 The current-voltage curve under light is shown in Figure 3The photoelectric conversion efficiency of the prepared device is 0.0038%, and the short-circuit current is 0.054mA / cm 2 , the open circuit voltage is 0.27V and the fill factor is 25.92%.

[0087] The synthesis methods of other A-π-D-π-A type corrole donor photovoltaic materials are similar to the above method and will not be repeated here.

[0088] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. An A-π-D-π-A type corrole donor photovoltaic material, characterized in that: It has the following chemical structure: ； M represents a metal element or 3 hydrogen elements; Ar is the following structure: ； A is the following structure: ； Wherein, R1 and R2 are alkyl or alkoxy groups having a carbon number of 0-20, and when the carbon number is 0, R1 and R2 are hydrogen or hydroxyl groups.

2. The method for preparing the A-π-D-π-A type corrole donor photovoltaic material according to claim 1, characterized in that: The following steps are involved: (1) Under the protection of inert gas and in the presence of an acid catalyst, 5-iodo-2-thiophenecarboxaldehyde and pyrrole are reacted in the dark to form compound A after purification: Compound A; (2) Under the protection of an inert gas, compound A and Ar-CHO are dissolved in a mixed solvent under light-proof conditions, reacted for 2±0.5 hours under the action of an acid catalyst, extracted, and an oxidant is added to react for 30±10 minutes, and compound B is formed after purification: Compound B; (3) Under the protection of an inert gas, A-Br and triisopropylsilyl acetylene are heated in a mixed solvent and a catalyst to undergo a Sonogashira coupling reaction, and after purification, compound C is formed: Compound C; (4) Removing the protecting group from compound C to obtain an intermediate product, the structure of which is: , and under the protection of an inert gas, the intermediate product and compound B are heated in the presence of a mixed solvent and a catalyst to perform a Sonogashira coupling reaction, and after purification, compound D is obtained, namely the A-π-D-π-A type corrole donor photovoltaic material: Compound D; (5) Dissolving the metal salt and compound D in a mixed solvent at room temperature, reacting in the dark, and obtaining the A-π-D-π-A type corrole donor photovoltaic material after purification: , where M represents a metal element.

3. The preparation method according to claim 2, characterized in that: The acid catalyst in step (1) is trifluoroacetic acid, and the amount used is 0.1 to 0.2 times the amount of 5-iodo-2-thiophenecarboxaldehyde; the reaction time is 10±5 minutes.

4. The preparation method according to claim 2, characterized in that: The mixed solvent in step (2) is water / methanol, and the volume ratio is 1:1-1:2; the concentration of Ar-CHO is 4-6 mmol / L; the acid catalyst in step (2) is concentrated hydrochloric acid with a mass fraction of 36-38%, and the amount used is 0.02-0.04 times the volume of the water / methanol mixed solvent, and the reaction temperature is 20-30 °C; The extractant in step (2) is dichloromethane, and the oxidant is 2,3-dichloro-5,6-dicyano-1,4-benzoquinone.

5. The preparation method according to claim 2, characterized in that: The mixed solvent in step (3) is tetrahydrofuran / triethylamine, with a volume ratio of 2:1 to 10:1; the catalysts used are bis(triphenylphosphine)palladium dichloride and cuprous iodide, with the amount of each being 0.1 to 0.2 times the amount of A-Br substance, and the reaction temperature is 60 to 80 °C.

6. The preparation method according to claim 2, characterized in that: The mixed solvent in step (4) is tetrahydrofuran / triethylamine, with a volume ratio of 2:1 to 10:1; the catalysts used are tri(dibenzylideneacetone)dipalladium and triphenylphosphine, with amounts of 0.2 times and 2 times the amount of compound B, respectively; the reaction temperature is 60 to 80 °C, and the reaction time is 12±4 hours.

7. The preparation method according to claim 2, characterized in that: In step (5), the metal salt is copper acetate, the mixed solvent is dichloromethane / methanol, the volume ratio is 1:1, the reaction temperature is 20-30°C, and the reaction time is 3±1 hours.

8. The use of the A-π-D-π-A type corrole donor photovoltaic material according to claim 1, characterized in that: The A-π-D-π-A type corrole donor photovoltaic material is used as a donor material for an organic solar cell.

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