Non-fullerene electron acceptor material with side chain substituted with Y6 as well as preparation method and application of non-fullerene electron acceptor material

Abstract

The invention discloses a non-fullerene electron acceptor material with a side chain substituted with Y6 as well as a preparation method and application of the non-fullerene electron acceptor material. According to the non-fullerene electron acceptor material, on the basis of a Y6 molecular skeleton, a side chain substituent group R1 is introduced, and the chemical structural general formula of the non-fullerene electron acceptor material is shown as a formula I: [formula I] # imgabs0 #, and R1 is # imgabs1 #. The non-fullerene electron acceptor material with the side chain replacing Y6 is synthesized through a simple preparation process, spectral absorption and active layer morphology of the acceptor material are efficiently regulated and controlled, and the performance of the non-fullerene electron acceptor material is improved. The absorption is enhanced in a visible light region of 500-700nm, the open-circuit voltage of the cell is increased, and the highest photoelectric conversion efficiency reaches 16.1%.

Description

Technical Field

[0001] The present invention relates to the technical field of organic solar cells, and more specifically to a non-fullerene electron acceptor material with side chain substituted Y6, and a preparation method and application thereof. Background Art

[0002] Bulk heterojunction organic solar cells have attracted extensive attention from researchers for their advantages such as light weight, flexibility, and large area. The morphology inside the active layer material determines key physical processes such as the generation and dissociation of excitons, the transfer and recombination of charges, and thus affects the photoelectric conversion efficiency (PCE) of organic solar cell devices. Regulation of the molecular skeleton can effectively regulate the morphology, but in order to achieve more precise regulation of the morphology, it is often necessary to regulate the substituted side chains on the molecular skeleton. For example, a large number of researchers have regulated the substituted side chains of the star non-fullerene acceptor material Y6, which has improved the PCE of organic solar cells as acceptor materials. The invention patent with publication number CN114181242A discloses a silane-substituted aromatic condensed ring compound and its preparation method and application, including: introducing a silane chain into the side chain structure of an organic small molecule to obtain an organic small molecule acceptor material with excellent solubility and a silane-substituted aromatic condensed ring; applying it to an organic solar cell to obtain a high energy conversion efficiency (15.3%); at the same time, during the external stress stretching process, it exhibits good intrinsic flexibility and stretchable mechanical properties. Therefore, regulating the substitution of side chains is an effective way to improve the PCE of organic photovoltaic cells. However, the PCE of organic photovoltaic cells still needs to be further improved to meet the high requirements of batteries in application fields. Summary of the invention

[0003] Due to the above-mentioned defects in the prior art, the present invention provides a new type of non-fullerene acceptor material. On the basis of the Y6 molecular skeleton, different side chain substitution groups are introduced to effectively regulate the morphology of the active layer, and it is applied to organic solar cells to further improve the PCE of the battery.

[0004] To achieve the above object, in the first aspect, the present invention provides a non-fullerene electron acceptor material, characterized in that: the non-fullerene electron acceptor material is based on the Y6 molecular skeleton, and a side chain substituent group R1 is introduced, and its chemical structure is shown in Formula I:

[0005] Where R1 is

[0006] In the above formula, R is selected from C1 to C 30 Straight chain, C1~C 30 One of the following: a branched chain, a benzene ring substituted with different alkyl chains, a thiophene ring substituted with different alkyl chains; R2 is selected from C1~C 30Straight chain, C1~C 30 One of the branches of

[0007] A is selected from one of the following structural units:

[0008]

[0009] Preferably, the chemical structure of the non-fullerene electron acceptor material is as shown below:

[0010]

[0011] Preferably, the chemical structure of the non-fullerene electron acceptor material is as shown below:

[0012]

[0013] In a second aspect, the present invention provides a method for preparing a non-fullerene electron acceptor material, characterized in that it comprises the following steps:

[0014] Step S1: The compound represented by formula II reacts with N-bromosuccinimide to obtain a compound represented by formula III:

[0015] Where R is selected from C1~C 30 Straight chain, C1~C 30 One of the following: branched chains, benzene rings substituted with different alkyl chains, and thiophene rings substituted with different alkyl chains;

[0016] Step S2: Under an inert gas environment, the compound represented by formula III reacts with lithium diisopropylamide and N,N-dimethylformamide to obtain a compound represented by formula IV:

[0017]

[0018] Step S3: Under an inert gas environment, the compounds represented by Formula IV and Formula V react to obtain a compound represented by Formula VI:

[0019] Wherein R2 is selected from C1~C 30 Straight chain, C1~C 30 One of the branches of

[0020] Step S4: reacting the compound represented by Formula VI with different indone to obtain the non-fullerene electron acceptor material as claimed in claim 1, i.e., the compound represented by Formula I.

[0021] Preferably, in steps S2 to S3, the inert gas is nitrogen or argon;

[0022] And / or, in step S1, the reaction solvent is one or both of tetrahydrofuran and N,N-dimethylformamide; the reaction temperature can be 0°C-100°C; and the reaction time is 1 to 24 hours;

[0023] And / or, in step S2, the reaction solution is tetrahydrofuran; the reaction temperature can be -80°C to 30°C; the reaction time is 1 to 24 hours;

[0024] And / or, in step S3, the reaction is carried out in a mixed system of an alkaline solution and an organic solvent; the catalyst is a palladium catalyst; the reaction temperature is 25° C. to 100° C.; and the reaction time is 1 to 48 hours;

[0025] And / or, in step S4, the reaction solvent is chloroform; the catalytic base is an organic base; the reaction temperature is 25° C.-100° C.; and the reaction time is 1-24 hours.

[0026] Furthermore, in the step S1, the reaction temperature is 25°C and the reaction time is 12 hours; in the step S2, the reaction is first carried out at a temperature of -78°C and then returned to 25°C for further reaction for 4 hours; in the step S3, the alkaline solution is an aqueous sodium carbonate solution; the organic solvent is tetrahydrofuran; the catalyst is tetrakistriphenylphosphine palladium, the reaction temperature is 80°C, and the reaction time is 36 hours; in the step S4, the catalytic base is pyridine; the reaction temperature is 68°C; and the reaction time is 12 hours.

[0027] In a third aspect, the present invention provides an application of a non-fullerene electron acceptor material in an organic solar cell, characterized in that the organic solar cell comprises a negative electrode, an electron transport layer stacked above the negative electrode, an active layer stacked above the electron transport layer, a hole transport layer stacked above the active layer, and a positive electrode stacked above the hole transport layer; the active layer comprises the non-fullerene electron acceptor material as described above.

[0028] In the last aspect, the present invention provides an application of a non-fullerene electron acceptor material in an organic solar cell, characterized in that the organic solar cell comprises a negative electrode, a hole transport layer stacked above the negative electrode, an active layer stacked above the hole transport layer, an electron transport layer stacked above the active layer, and a positive electrode stacked above the electron transport layer; the active layer comprises the non-fullerene electron acceptor material as described above.

[0029] Compared with the prior art, the above invention has the following advantages or beneficial effects:

[0030] The present invention provides and prepares a new type of side chain substituted non-fullerene acceptor material, and uses it as an acceptor material for an organic solar cell, which has the following advantages: (1) a simple preparation process, which reduces the complexity of the synthesis; (2) the side chain substitution efficiently regulates the spectral absorption of the acceptor material, and it can be found from the ultraviolet-visible light absorption spectrum that it has enhanced absorption in the visible light region of 500 to 700 nm; (3) the side chain substitution can regulate the morphology of the active layer, and achieve a high open circuit voltage (V oc ) improvement; (4) the acceptor material BTP-PhTO-1 provided by the present invention has excellent photoelectric conversion efficiency, and the photoelectric conversion efficiency exceeds 16%. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The present invention and its features and advantages will become more apparent upon reading the detailed description of non-limiting embodiments made with reference to the following accompanying drawings.

[0032] Figure 1 The UV-visible absorption spectra of the non-fullerene acceptor materials Y6 and BTP-PhTO-1 in one embodiment of the present invention;

[0033] Figure 2 This is the JV curve of an organic photovoltaic cell assembled from non-fullerene acceptor material Y6 and BTP-PhTO-1 in an application example of the present invention. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments will be described clearly and completely below. Obviously, the embodiments described below are only part of the embodiments of the present invention, rather than all the embodiments.

[0035] The terms "comprise", "include" and any variations thereof in the following embodiments and comparative examples are intended to cover non-exclusive inclusions, for example, a process, method, or product comprising a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units that are not listed, or may optionally include other steps or units that are inherent to these processes, methods, or products.

[0036] In addition, the experimental methods shown in the following examples are conventional methods unless otherwise specified; the materials and reagents are purchased from commercial sources unless otherwise specified.

[0037] Example 1: Preparation of BTP-PhTO-1

[0038]

[0039] Under nitrogen protection, compound 1 was dissolved in tetrahydrofuran solution, cooled to 0°C, 2.2 eq N-bromosuccinimide was added, the mixture was returned to room temperature and stirred overnight, sodium thiosulfate aqueous solution was added to quench the reaction, dichloromethane was extracted, the solvent was removed by rotation, and compound 2 was separated and purified by column chromatography, with a yield of 90%. MS (MALDI-TOF): 820.1 [M] + .

[0040] Under nitrogen protection, compound 2 was dissolved in tetrahydrofuran solution, lithium diisopropylamide (2.2 eq.) was added dropwise at -78°C, reacted for 1 hour at -78°C, returned to room temperature for 2 hours, cooled to -78°C, N,N-dimethylformamide (2.4 eq.) was added, reacted for 0.5 hour at -78°C, returned to room temperature for 1 hour, water was added to quench the reaction, extracted with dichloromethane, the solvent was removed by rotation, and compound 3 was separated and purified by column chromatography, with a yield of 50%. MS (MALDI-TOF): 876.1 [M] + .

[0041] Under nitrogen protection, a 2M sodium carbonate aqueous solution and 5% eq tetrakis triphenylphosphine palladium were added to a tetrahydrofuran solution of compound 3 and compound 4 (5 eq), and the mixture was reacted at 78°C for 36 hours, cooled to room temperature, extracted with dichloromethane after adding water, dried over anhydrous magnesium sulfate, and separated by column chromatography to purify compound 5 after removing the solvent, with a yield of 73%. MS (MALDI-TOF): 1640.3 [M] + .

[0042] Compound 5 and INCN-2F (6 eq.) were dissolved in chloroform, and a few drops of pyridine were added as a catalyst. The mixture was reacted under reflux for 12 hours, cooled to room temperature, and the solvent was removed by vortexing. Compound BTP-PhTO-1 was obtained by column chromatography separation and purification with a yield of 86%. MS (MALDI-TOF): 2064.0 [M] + .

[0043] Example 2: Preparation of BTP-PhTO-2

[0044]

[0045] Compound 5 and INCN-2Cl (6 eq.) were dissolved in chloroform, and a few drops of pyridine were added as a catalyst. The mixture was reacted under reflux for 12 hours, cooled to room temperature, and the solvent was removed by vortexing. Compound BTP-PhTO-2 was obtained by column chromatography separation and purification, with a yield of 82%. MS (MALDI-TOF): 2129.9 [M] + .

[0046] Example 3: Spectral absorption measurement of acceptor materials Y6 and BTP-PhTO-1

[0047] Reference material Y6 and BTP-PhTO-1 were dissolved in chloroform respectively, and the compound was evenly thrown on the quartz slice by the method of film throwing. The absorption spectrum of the compound is shown in Figure 1 BTP-PhTO-1 has a higher absorption rate than Y6 in the visible light region of 500-700nm.

[0048] Example 4: Preparation of organic solar cells

[0049] The organic solar cell includes a negative electrode, an electron transport layer stacked on the negative electrode, an active layer stacked on the electron transport layer, a hole transport layer stacked on the active layer, and a positive electrode stacked on the hole transport layer; the active layer includes a non-fullerene electron acceptor material as in Example 1 or 2.

[0050] Specifically, the conductive polymer (styrene sulfonate) doped poly (3,4-ethylenedioxythiophene) (PEDOT:PSS) was thrown onto the indium tin oxide (ITO) interface at a rotation speed of 3000 for 30 seconds, baked at 150°C for 10 minutes, and transferred to a glove box filled with nitrogen. The reference material Y6 and the BTP-PhTO-1 prepared in Example 1 were respectively mixed with the polymer donor PM6 in chloroform and stirred to dissolve. The prepared solution was thrown onto the ITO sheet at different rotation speeds, thermally annealed at 100°C, then a PDINN modification layer was formed, and finally a silver electrode was evaporated to obtain an organic solar cell device. The AM1.5G intensity (100mW / cm 2 ) were used to measure the open circuit voltage, short circuit current and fill factor of the prepared solar cell device. The corresponding JV curves were Figure 2 .

[0051] Based on reference material Y6, the battery was manufactured and characterized according to the procedure of Example 4. Open circuit voltage V oc =0.835V, short circuit current J sc =24.7mA / cm 2 , filling factor FF = 75.4%, conversion efficiency PCE = 15.5%.

[0052] Based on the BTP-PhTO-1 of Example 1, a battery was manufactured and characterized according to the procedure of Example 6. Open circuit voltage V oc =0.866V, short circuit current J sc =24.6mA / cm 2 , fill factor FF = 75.7%, conversion efficiency PCE = 16.1%, its open circuit voltage and PCE are significantly improved compared with Y6

[0053] Example 5: Preparation of organic solar cells

[0054] The preparation method of the organic solar cell is similar to that of Example 4, but different from that of Example 4 in that the organic solar cell includes a negative electrode, a hole transport layer stacked on the negative electrode, an active layer stacked on the hole transport layer, an electron transport layer stacked on the active layer, and a positive electrode stacked on the electron transport layer; the active layer includes a non-fullerene electron acceptor material as in Example 1 or 2.

[0055] In summary, the present invention discloses a non-fullerene electron acceptor material with side chain substitution of Y6, a preparation method and application thereof. The non-fullerene electron acceptor material is a material in which a side chain substitution group R1 is introduced on the basis of the Y6 molecular skeleton. The present invention synthesizes a non-fullerene electron acceptor material through a simple preparation process, and the side chain substitution of Y6 efficiently regulates the spectral absorption and active layer morphology of the acceptor material, has enhanced absorption in the visible light region of 500 to 700 nm, realizes the improvement of the open circuit voltage of the battery, and the photoelectric conversion efficiency is as high as 16.1%.

[0056] Those skilled in the art should understand that those skilled in the art can implement variations by combining the prior art and the above embodiments, which will not be described in detail here. Such variations do not affect the essential content of the present invention, and will not be described in detail here.

[0057] The above describes the preferred embodiments of the present invention. It should be understood that the present invention is not limited to the above-mentioned specific embodiments, and the devices and structures that are not described in detail should be understood to be implemented in a common manner in the art; any technician familiar with the art can use the above-disclosed methods and technical contents to make many possible changes and modifications to the technical solutions of the present invention without departing from the scope of the technical solutions of the present invention, or modify them into equivalent embodiments of equivalent changes, which does not affect the essential content of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention are still within the scope of protection of the technical solutions of the present invention.

Claims

1. A non-fullerene electron acceptor material, characterized in that: The non-fullerene electron acceptor material is based on the Y6 molecular skeleton, and a side chain substituent group R1 is introduced. The general chemical structure is shown in Formula I: [Formula I] Where R1 is In the above formula, R is selected from C1 to C 30 Straight chain, C1~C 30 One of the following: a branched chain, a benzene ring substituted with different alkyl chains, a thiophene ring substituted with different alkyl chains; R2 is selected from C1~C 30 Straight chain, C1~C 30 One of the branches of A is selected from one of the following structural units:

2. A non-fullerene electron acceptor material according to claim 1, characterized in that: The chemical structural formula of the non-fullerene electron acceptor material is shown below:

3. A non-fullerene electron acceptor material according to claim 1, characterized in that: The chemical structural formula of the non-fullerene electron acceptor material is shown below:

4. A method for preparing a non-fullerene electron acceptor material, characterized in that: The following steps are involved: Step S1: The compound represented by Formula II reacts with N-bromosuccinimide to obtain a compound represented by Formula III: [Formula II] [Formula III] Where R is selected from C1~C 30 Straight chain, C1~C 30 One of the following: branched chains, benzene rings substituted with different alkyl chains, and thiophene rings substituted with different alkyl chains; Step S2: Under an inert gas environment, the compound represented by formula III reacts with lithium diisopropylamide and N,N-dimethylformamide to obtain a compound represented by formula IV: [Formula IV] Step S3: Under an inert gas environment, the compounds represented by Formula IV and Formula V react to obtain a compound represented by Formula VI: [Formula V] [Formula VI] Wherein R2 is selected from C1~C 30 Straight chain, C1~C 30 One of the branches of Step S4: reacting the compound represented by Formula VI with different indone to obtain the non-fullerene electron acceptor material as claimed in claim 1, i.e., the compound represented by Formula I.

5. The method for preparing a non-fullerene electron acceptor material according to claim 4, characterized in that: In the steps S2 to S3, the inert gas is nitrogen or argon; And / or, in step S1, the reaction solvent is one or both of tetrahydrofuran and N,N-dimethylformamide; the reaction temperature can be 0°C-100°C; and the reaction time is 1 to 24 hours; And / or, in step S2, the reaction solution is tetrahydrofuran; the reaction temperature can be -80°C to 30°C; the reaction time is 1 to 24 hours; And / or, in step S3, the reaction is carried out in a mixed system of an alkaline solution and an organic solvent; the catalyst is a palladium catalyst; the reaction temperature is 25° C. to 100° C.; and the reaction time is 1 to 48 hours; And / or, in step S4, the reaction solvent is chloroform; the catalytic base is an organic base; the reaction temperature is 25° C.-100° C.; and the reaction time is 1-24 hours.

6. The method for preparing a non-fullerene electron acceptor material according to claim 5, characterized in that: In the step S1, the reaction temperature is 25°C and the reaction time is 12 hours; in the step S2, the reaction is first carried out at a temperature of -78°C and then returned to 25°C for further reaction for 4 hours; in the step S3, the alkaline solution is an aqueous sodium carbonate solution; the organic solvent is tetrahydrofuran; the catalyst is tetrakistriphenylphosphine palladium, the reaction temperature is 80°C, and the reaction time is 36 hours; in the step S4, the catalytic base is pyridine; the reaction temperature is 68°C; and the reaction time is 12 hours.

7. Application of non-fullerene electron acceptor materials in organic solar cells, characterized in that: The organic solar cell comprises a negative electrode, an electron transport layer stacked on the negative electrode, an active layer stacked on the electron transport layer, a hole transport layer stacked on the active layer, and a positive electrode stacked on the hole transport layer; the active layer comprises the non-fullerene electron acceptor material as described in any one of claims 1 to 3.

8. Application of non-fullerene electron acceptor materials in organic solar cells, characterized in that: The organic solar cell comprises a cathode, a hole transport layer stacked on the cathode, an active layer stacked on the hole transport layer, an electron transport layer stacked on the active layer, and a cathode stacked on the electron transport layer; the active layer comprises the non-fullerene electron acceptor material as claimed in any one of claims 1 to 3.

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