Non-fullerene acceptor material based on thiophene derivative pi bridge as well as preparation method and application of non-fullerene acceptor material

Abstract

The invention discloses a non-fullerene acceptor material based on a thiophene derivative pi bridge as well as a preparation method and application of the non-fullerene acceptor material. The non-fullerene acceptor material has two or more conjugated molecular junctions of pi-A-D-A type repetitive units, and comprises three types of molecular building blocks, namely a thiophene derivative pi bridge, an aromatic ring core D with an electron donating property and a terminal unit A with an electron withdrawing property. Organic photovoltaic non-fullerene acceptor molecules can be flexibly constructed by utilizing multi-selectivity and combination of three types of molecular blocks, and introduction of a thiophene derivative pi bridge is beneficial to enhancement of a D-A effect, improvement of a conjugation degree, enhancement of intermolecular accumulation of an acceptor and improvement of charge mobility. The non-fullerene acceptor material can be prepared by using relatively common tinning reaction and Stille coupling reaction, and has a stronger electron donating and withdrawing effect, proper molecular accumulation and relatively high photovoltaic performance.

Description

Technical Field

[0001] The present invention relates to the technical field of organic solar cells, and more specifically to a non-fullerene acceptor material based on a thiophene derivative π bridge, and a preparation method and application thereof. Background Art

[0002] As the global demand for renewable energy continues to rise, solar photovoltaic power generation, as one of the important renewable energy sources, is receiving widespread attention. As an emerging photovoltaic technology, organic solar cells have shown great potential in the fields of flexible, colorful, transparent devices and indoor photovoltaics due to their advantages such as semi-transparency, easy processing, lightweight and large-area preparation (Liu et al., Advanced Materials Technologies, 2021, 6, 2000960). Thanks to the progress of material innovation and device manufacturing process, the performance of organic solar cells has been significantly improved in recent years, especially the development of ADA-type non-fullerene acceptor materials, which has enabled the photoelectric conversion efficiency of small-area devices in the laboratory to exceed 20%. ADA-type non-fullerene acceptor molecules are composed of an electron-donating fused aromatic ring core D and an electron-withdrawing terminal unit A. They have the advantage of modular synthesis, which facilitates rapid receptor construction and performance optimization by selecting different molecular building blocks. In addition, the ADA-type non-fullerene acceptor is connected by π bridges to form oligomers or even polymers, which have better stability than small molecules. This is mainly attributed to the fact that this structural extension can greatly increase the size of the molecule and effectively increase the glass transition temperature (T g ). Therefore, it is of great research value to continue to develop π-bridge polymer-based non-fullerene acceptor materials (Peng et al., Advanced Materials, 2023, 2300175). Thiophene is the most commonly used π-bridge unit with electron-donating properties. Its introduction can increase the highest occupied molecular orbital energy level of the acceptor molecule. At the same time, the sulfur atom forms non-covalent interactions with various elements in the molecule, which helps to enhance the planarity of the molecular skeleton and promote close stacking between molecules, thereby improving the charge transfer capacity (Liu et al., Nature Communications, 2023, 12, 4148). Therefore, thiophene-based photovoltaic materials generally have lower LUMO energy levels, narrower optical band gaps, and higher spectral utilization efficiency than phenyl materials, thereby achieving higher short-circuit current density (J sc ). However, the current photoelectric conversion efficiency of the polymeric non-fullerene acceptor materials based on thiophene π-bridges still lags behind that of small molecule acceptor materials. Therefore, how to introduce a better π-bridge to improve the photoelectric conversion efficiency is a technical problem that needs to be solved urgently. Summary of the invention

[0003] Due to the defects of the prior art, the present invention provides a non-fullerene acceptor material based on a thiophene derivative π bridge, a preparation method and application thereof, which has stronger electron donating and pulling effects, suitable molecular stacking and higher photovoltaic performance.

[0004] To achieve the above objectives, in the first aspect, the present invention provides a non-fullerene acceptor material based on a thiophene derivative π bridge, having a conjugated molecular junction of two or more π-ADA type repeating units, including three types of molecular building blocks: a thiophene derivative π bridge, an aromatic ring core D with electron-donating properties, and an end unit A with electron-withdrawing properties; having a structure shown in Formula I or Formula II:

[0005]

[0006] Wherein the π bridge is a thiophene derivative, D1, D2 and D3 are condensed aromatic units, A1 to A6 are electron-withdrawing units, n is 2 to 100, and the thiophene derivative π bridge has any structure shown in Formula III:

[0007]

[0008] Wherein, R1 is independently selected from C1~C 20 The alkyl group;

[0009] Ar is a 6- to 14-membered aryl group or a 5- to 12-membered heteroaryl group, and the heteroatom is selected from N, O and S.

[0010] The present invention can flexibly construct organic photovoltaic non-fullerene receptor molecules by utilizing the multiple selectivity and combination of three types of molecular building blocks. The introduction of thiophene derivative π bridge is conducive to enhancing the DA effect, improving the degree of conjugation, and enhancing the intermolecular stacking of the receptor, thereby improving the charge mobility.

[0011] Furthermore, D1, D2 and D3 have any structure shown in Formula IV:

[0012]

[0013] Wherein, X1 and X2 are independently selected from O, S or Se; R2, R3 and R4 are independently selected from C1~C 24 A straight chain or branched chain alkyl group.

[0014] Furthermore, A1-A6 has any structure shown in Formula V:

[0015]

[0016] Wherein, X3 and X4 are independently selected from H, F, Cl, Br, CH3, OCH3 or CN.

[0017] In a second aspect, the present invention provides a method for preparing the non-fullerene acceptor material based on a thiophene derivative π bridge as described above, comprising the following steps:

[0018] (1) The thiophene derivative is subjected to tination reaction to obtain compound a:

[0019]

[0020] (2) Compound a obtained in step (1) is subjected to Stille coupling reaction with the bromide b of the small molecule receptor NF under the catalytic action of a catalyst and a ligand to obtain compound c:

[0021]

[0022] or

[0023] .

[0024] Furthermore, in the step (1), the molar ratio of the tin compound of the thiophene derivative, the catalyst and the ligand is 1:0.03~0.1:0.6~0.2; in the step (2), the solvent of the Stille coupling reaction is selected from at least one of dioxane, toluene, xylene or chlorobenzene; the molar ratio of the small molecule receptor NF and compound b is 1:2~4; the catalyst is selected from at least one of tetrakis(triphenylphosphine)palladium, bis(triphenylphosphine)palladium dichloride, palladium acetate or tris(dibenzylideneacetone)dipalladium, and the ligand is selected from at least one of tri-tert-butylphosphine, tris(o-methylphenyl)phosphine or 4,5-bis(diphenylphosphine)-9,9-dimethylxanthene; the reaction temperature of the Stille coupling reaction is 90~140°C, and the reaction time is 6~48 hours.

[0025] In a third aspect, the present invention provides a semiconductor material comprising at least one of the non-fullerene acceptor material based on a thiophene derivative π bridge as described above and the non-fullerene acceptor material based on a thiophene derivative π bridge prepared by the preparation method as described above.

[0026] In the last aspect, the present invention provides a solar cell device, comprising a substrate, an anode, an anode modification layer, a photoactive layer, a cathode modification layer and a cathode, wherein the photoactive layer is prepared by blending the non-fullerene acceptor material based on a thiophene derivative π bridge and an electron donor material; the non-fullerene acceptor material based on a thiophene derivative π bridge is at least one of the non-fullerene acceptor material based on a thiophene derivative π bridge as described above and the non-fullerene acceptor material based on a thiophene derivative π bridge prepared by the preparation method as described above.

[0027] Furthermore, the electron donor material is at least one of PTB7-Th, PBDB-T and PM6; the mass ratio of the electron donor material to the non-fullerene acceptor material based on the thiophene derivative π bridge in the photoactive layer is 1:1 to 1.5.

[0028] Compared with the prior art, the above invention has the following advantages or beneficial effects:

[0029] The present invention provides a non-fullerene acceptor material based on a thiophene derivative π bridge. By using a strongly electron-donating substituted thiophene (such as edot, etc.) as a connector of the acceptor, the conjugation degree of the acceptor molecule is increased, the absorption band gap of the molecule is increased, and the charge transfer between and within the molecule is enhanced, which is conducive to obtaining a large short-circuit current in an organic solar cell. Secondly, by introducing the thiophene derivative π bridge, not only an intramolecular S...O non-covalent interaction but also a H...O non-covalent interaction can be formed, thereby enhancing the intermolecular stacking of the acceptor material and improving the carrier transport performance and the filling factor of the device.

[0030] In addition, the non-fullerene acceptor material based on thiophene derivative π bridge provided by the present invention has good film-forming properties. The material is used in solar cells. After device preparation and optimization, the conversion efficiency can reach more than 18%. At the same time, the open circuit voltage of the battery is higher than 0.92 volts and the short circuit current is higher than 25 mA / cm 2 , the filling factor is higher than 78%. 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 is the molecular formula of compound X-1 prepared in the example of the present invention.

[0033] Figure 2 The Maldi-Tof mass spectra of compound X-1 prepared in the example of the present invention and comparative example S1 are shown.

[0034] Figure 3 The UV absorption graphs of compound X-1 prepared in the example of the present invention and comparative example S1 are shown. DETAILED DESCRIPTION

[0035] 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.

[0036] In the following examples and comparative examples of the present invention, "C1 to C 20 ” and “C1~C 24" refers to the number of carbon atoms contained in the group, such as C1~C 20 The alkyl group refers to an alkyl group with 1 to 20 carbon atoms; in the present invention, "alkyl" refers to a group formed by an alkane compound losing any hydrogen atom, and the alkane compound includes straight-chain alkanes, branched alkanes, and cycloalkanes; in the present invention, "aryl" is a group formed by losing any hydrogen atom on the aromatic ring in an aromatic compound molecule; the aromatic compound includes a compound containing an aromatic ring and a compound in which at least one hydrogen atom on the aromatic ring is substituted by an alkyl group.

[0037] In the description and claims of the present invention:

[0038] The non-fullerene acceptor material based on the thiophene derivative π bridge has a conjugated molecular junction of two or more π-ADA type repeating units, including three types of molecular building blocks: the thiophene derivative π bridge, the electron-donating aromatic ring core D, and the electron-withdrawing terminal unit A; and has a structure shown in Formula I or Formula II:

[0039]

[0040] Wherein the π bridge is a thiophene derivative, D1, D2 and D3 are condensed aromatic units, A1 to A6 are electron-withdrawing units, n is 2 to 100, and the thiophene derivative π bridge has any structure shown in Formula III:

[0041]

[0042] Wherein, R1 is independently selected from C1~C 20 Ar is a 6- to 14-membered aryl group or a 5- to 12-membered heteroaryl group, and the heteroatom is selected from N, O and S.

[0043] The following specific embodiments and examples may be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments and examples; and the experimental methods shown in the following embodiments are conventional methods unless otherwise specified; the materials and reagents are purchased from commercial sources unless otherwise specified.

[0044] Example 1

[0045] This embodiment provides a non-fullerene acceptor material based on a thiophene derivative π bridge, having a conjugated molecular junction of two or more π-ADA type repeating units, including three types of molecular building blocks: a thiophene derivative π bridge, an electron-donating aromatic ring core D, and an electron-withdrawing terminal unit A; having a structure shown in Formula I or Formula II:

[0046]

[0047] Wherein the π bridge is a thiophene derivative, D1, D2 and D3 are condensed aromatic units, A1 to A6 are electron-withdrawing units, n is 2 to 100, and the thiophene derivative π bridge has any structure shown in Formula III:

[0048]

[0049] Wherein, R1 is independently selected from C1~C 20 The alkyl group;

[0050] Ar is a 6- to 14-membered aryl group or a 5- to 12-membered heteroaryl group, and the heteroatom is selected from N, O and S.

[0051] As a preferred technical solution, D1, D2 and D3 have any structure shown in Formula IV:

[0052]

[0053] Wherein, X1 and X2 are independently selected from O, S or Se; R2, R3 and R4 are independently selected from C1~C 24 A straight chain or branched chain alkyl group.

[0054] The A1-A6 has any structure shown in Formula V:

[0055]

[0056] Wherein, X3 and X4 are independently selected from H, F, Cl, Br, CH3, OCH3 or CN

[0057] From the above description and structural formula, it can be found that by utilizing the multi-selectivity and combination of three types of molecular building blocks, organic photovoltaic non-fullerene receptor molecules can be flexibly constructed. The introduction of thiophene derivative π bridge is beneficial to enhance the DA effect, improve the degree of conjugation, enhance the intermolecular stacking of the receptor, and improve the charge mobility.

[0058] Example 2

[0059] This embodiment provides a method for preparing a non-fullerene acceptor material based on a thiophene derivative π bridge as described in Embodiment 1, comprising the following steps:

[0060] (1) The thiophene derivative is subjected to tination reaction to obtain compound a:

[0061]

[0062] (2) Compound a obtained in step (1) is subjected to Stille coupling reaction with the bromide b of the small molecule receptor NF under the catalytic action of a catalyst and a ligand to obtain compound c:

[0063]

[0064] or

[0065] .

[0066] As some preferred preparation parameters, in the step (1), the molar ratio of the tin compound of the thiophene derivative, the catalyst and the ligand is 1:0.03~0.1:0.6~0.2; in the step (2), the solvent of the Stille coupling reaction is selected from at least one of dioxane, toluene, xylene or chlorobenzene; the molar ratio of the small molecule receptor NF and compound b is 1:2~4; the catalyst is selected from at least one of tetrakis(triphenylphosphine)palladium, bis(triphenylphosphine)palladium dichloride, palladium acetate or tris(dibenzylideneacetone)dipalladium, and the ligand is selected from at least one of tri-tert-butylphosphine, tri(o-methylphenyl)phosphine or 4,5-bis(diphenylphosphine)-9,9-dimethylxanthene; the reaction temperature of the Stille coupling reaction is 90~140°C, and the reaction time is 6~48 hours.

[0067] From the steps of the above preparation method, it can be seen that the non-fullerene acceptor material (compound c) in Example 1 can be prepared by using the more common tination reaction and Stille coupling reaction. The process is relatively easy to control, the preparation process is easy to scale up, and the raw materials are easy to obtain and the cost is low.

[0068] To further help understand the technical solution of the present invention, the technical solution of the present invention is described in more detail below through several specific implementation examples.

[0069] Example 1: Preparation and characterization of receptor material X-1

[0070] See also Figure 1 is the molecular formula of the receptor material X-1. The synthetic route of the receptor material X-1 is as follows:

[0071] Step (1): Compound 1 is subjected to tination reaction to obtain compound 2:

[0072] ;

[0073] Compound 1 (710 mg) and ultra-dry tetrahydrofuran (30 ml) were added to a 100 ml two-necked round-bottom flask, and then n-butyl lithium (5.2 ml, 2.4 M) was slowly added dropwise at -78 °C. After the addition, the reaction solution continued to react at this temperature for 1 hour, and then trimethyltin chloride (1 M) was added thereto, and the reaction continued for 1 hour. After the reaction was completed, water was added to quench the reaction, and the mixture was extracted with ether. The organic phase was dried over anhydrous sodium sulfate and then spin-dried to obtain a crude product, which was then recrystallized in ethanol to obtain compound 2 (white solid, 1.5 g, 66%), 1HNMR (400MHz, CDCl3, ppm): δ: 4.15 (S, 4H), 0.33 (s, 18H).

[0074] Step (2): Compound 2 obtained in step (1) is coupled with compound 3 to obtain receptor material X-1:

[0075]

[0076] In a 50 ml round-bottom flask, compound 2 (100 mg), compound 3 (862 mg), and toluene (20 ml) were added, and after bubbling in nitrogen for 15 mins, tetrakistriphenylphosphine palladium (5 mg) was added, and the reaction was carried out at 110°C for 12 h. After the reaction was completed, water was added to quench the reaction, and the organic phase was extracted with chloroform. After drying the organic phase over anhydrous sodium sulfate, it was spin-dried to obtain a crude product, which was separated and purified by silica gel column chromatography (eluent: chloroform: petroleum ether = 1:1, v / v) to obtain receptor X-1 (680 mg, 87.2%). 1H NMR (500 MHz,CDCl3): δ=9.14 (d, 4H); 8.73(d, 2H); 8.57(t, 2H); 8.37(m, 2H); 8.10(m, 2H);7.62(t, 2H); 4.80(s, 8H); 4.59(t, 4H); 3.22(s, 8H); 2.15(m, 4H); 1.88(m, 8H);1.54 (m, 12H); 1.42-0.66(m, 236H). Maldi-Tof: found, 3642.89, its Tof spectrum is as follows Figure 1 As shown, the UV absorption spectrum is Figure 2 shown.

[0077] Example 2: Preparation of acceptor material X-2

[0078] In a 50ml round-bottom flask, compound 4 (200), compound 2 (50mg), toluene (20ml) were added, and after bubbling in nitrogen for 15mins, tris(dibenzylideneacetone)dipalladium (5mg) and tris(o-methylphenyl)phosphine (10mg) were added, and the reaction was carried out at 110℃ for 12h. After the reaction was completed, water was added to quench the reaction, and chloroform was used for extraction. The organic phase was dried over anhydrous sodium sulfate, concentrated, and then precipitated in methanol to obtain receptor X-2 (178 mg, 89%). Mn: 18320; PDI: 2.7. The reaction process is as follows:

[0079]

[0080] The UV absorption spectrum of acceptor material X-2 is similar to that of acceptor material X-1.

[0081] Comparative Example

[0082] Compound 2 obtained in the first step of Example 1 is coupled with compound 5 to obtain receptor material S1:

[0083]

[0084] In a 50 ml round-bottom flask, compound 2 (100 mg), compound 3 (862 mg), and toluene (20 ml) were added, and after bubbling in nitrogen for 15 mins, tetrakistriphenylphosphine palladium (5 mg) was added, and the reaction was carried out at 110°C for 12 h. After the reaction was completed, water was added to quench the reaction, and the organic phase was extracted with chloroform. After drying the organic phase over anhydrous sodium sulfate, it was spin-dried to obtain a crude product, which was separated and purified by silica gel column chromatography (eluent: chloroform: petroleum ether = 1:1, v / v) to obtain receptor X-1 (627 mg, 72.4%). 1H NMR (500 MHz, CDCl3): δ =9.18 (s, 2H); 9.14 (s, 2H); 8.76 (d, 2H); 8.55 (dt, 2H); 8.14 (s, 2H); 7.99 (d, 2H); 7.66 (s, 2H); 7.65 (t, 2H); 4.79(s, 8H); 3.23(s, 8H); 2.16(m, 4H);1.88(m, 8H); 1.59-1.49 (m, 20H); 1.44-0.84(m, 186H); 0.84-0.74(m, 36H).Maldi-Tof: found, 3583.70, the Tof chart is as follows Figure 1 As shown, the UV absorption spectrum is Figure 2 shown.

[0085] S1 is a non-fullerene acceptor material bridged by thiophene, and X-1 is a non-fullerene acceptor material based on a π bridge of a thiophene derivative. Their thin film UV absorption spectra are shown in the attached Figure 3 Compared with the acceptor material S1, X-1 has strong and narrow absorption in the wavelength range of 750~850nm, and the maximum absorption peak is slightly red-shifted, which indicates that the introduction of the thiophene derivative π bridge can not only enhance the intramolecular donor-acceptor interaction, but also enhance the intermolecular stacking of the acceptor material by forming intramolecular S...O non-covalent interactions and H...O non-covalent interactions.

[0086] Example 3

[0087] This embodiment provides a semiconductor material, comprising at least one of the non-fullerene acceptor material based on a thiophene derivative π bridge as described in Embodiment 1 and the non-fullerene acceptor material based on a thiophene derivative π bridge prepared by the preparation method described in Embodiment 2.

[0088] Example 4

[0089] The present embodiment provides a solar cell device, comprising a substrate, an anode, an anode modification layer, a photoactive layer, a cathode modification layer and a cathode, wherein the photoactive layer is prepared by blending the non-fullerene acceptor material based on a thiophene derivative π bridge and an electron donor material; the non-fullerene acceptor material based on a thiophene derivative π bridge is at least one of the non-fullerene acceptor material based on a thiophene derivative π bridge as described in Example 1 and the non-fullerene acceptor material based on a thiophene derivative π bridge prepared by the preparation method described in Example 2.

[0090] Preferably, the electron donor material is at least one of PTB7-Th, PBDB-T and PM6; the mass ratio of the electron donor material to the non-fullerene acceptor material based on the thiophene derivative π bridge in the photoactive layer is 1:1 to 1.5. The solar cell device comprises a substrate, an anode, an anode modification layer, a photoactive layer, a cathode modification layer and a cathode. Preferably, the substrate is glass or polyethylene terephthalate (PET), the anode is indium tin oxide (ITO); the anode modification layer is poly (3,4-ethylenedioxythiophene): polystyrene sulfonate (PEDOT:PSS); the cathode modification layer is poly [(9,9-bis (3'-(N,N-dimethylamino)propyl) fluorenyl-2,7-diyl) -alt- [(9,9-di-n-octylfluorenyl-2,7-diyl) -bromide (PFN-Br); the cathode is silver.

[0091] The solvent used in the photoactive layer is at least one of toluene, xylene, trimethylbenzene, chloroform, chlorobenzene, dichlorobenzene and trichlorobenzene. The concentration of the electron donor material in the photoactive layer can be 1-20 mg / mL, preferably 5-10 mg / mL, and the concentration of the electron acceptor can be 1.5-30 mg / mL, preferably 5-15 mg / mL; the photoactive layer is annealed at a temperature of 50-150° C. and an annealing time of 1-30 minutes.

[0092] The technical solution of the present invention is described in more detail below through specific application examples.

[0093] Application Examples

[0094] The solar cell device adopts an upright device structure, specifically glass substrate / ITO / PEDOT:PSS / PBDB-T:X-1 / PFN-Br / silver. Among them, the ITO layer is attached to the glass substrate. ITO and glass substrate are collectively referred to as ITO glass. The ITO glass is washed with detergent, water, acetone and isopropanol in sequence under ultrasound for thirty minutes each. Then it is dried in an oven at 90°C overnight. After the ITO glass is treated with ultraviolet ozone for 15 minutes, PEDOT:PSS is spin-coated on the ITO layer, placed in a 140°C oven for heating for 15 minutes, and then quickly transferred to a glove box for standby use. The polymer donor PM6 (purchased from Shenzhen Ruixun Optoelectronic Materials Technology Co., Ltd.) and the non-fullerene acceptor material X-1 or comparative example S1 were dissolved in chlorobenzene at a weight ratio of 1:1.2, and 0.2% by volume of 1,8-diiodooctane was added as an additive. The total concentration of the solution was 16 mg / mL. The solution was stirred at 50°C for 4 hours, and then the solution was spin-coated on the PEDOT:PSS film as an active layer with a thickness of about 150 nm. In order to improve the electron input efficiency, a methanol solution of PFN-Br (0.5 mg / mL containing 0.25% mass concentration of melamine) was spin-coated on the active layer. Finally, the negative electrode of the battery was vacuumed at a degree of about 1×10 -4 The device is completed by thermal evaporation of 150nm silver electrode under Pa conditions. The area of ​​the device is 4mm 2 .

[0095] Performance Testing:

[0096] The device was tested by using an Oriel sol3A (Newport) solar simulator to simulate AM1.5G (100mW / cm 2 ) and measured using a Keithley 2400 digital source meter tester.

[0097] The parameters of the solar cell devices obtained from the application examples are summarized in Table 1.

[0098] Compared with the performance of the solar cell prepared based on the comparative example, the solar cell based on Example 1 shows higher device performance, which shows that the modification of thiophene derivatives in Example 1 can indeed improve the efficiency of charge transfer between molecules and within molecules, and comprehensively improve the battery performance. In addition, the non-fullerene acceptor material X-1 based on the π bridge of thiophene derivatives has good film-forming properties. The material is used in solar cells. After device preparation and optimization, the conversion efficiency can reach more than 18%. At the same time, the open circuit voltage of the battery is higher than 0.92 volts and the short circuit current is higher than 25mA / cm 2 , the filling factor is higher than 78%.

[0099] Table 1 Parameters of solar cell devices prepared based on acceptor materials X-1 and S1

[0100] Active layer <![CDATA[V oc (V)]]> <![CDATA[J sc (mA / cm 2 )]]> FF PCE(%) PM6-X-1 0.924 25.2 78.19 18.21 PM6-S1 0.910 24.47 77.07 17.16

[0101] From the test results of the above embodiments and application examples, it can be seen that the present invention can flexibly construct organic photovoltaic non-fullerene receptor molecules by utilizing the multi-selectivity and combination of three types of molecular building blocks. The introduction of thiophene derivative π bridge is beneficial to enhance the DA effect, improve the degree of conjugation, enhance the intermolecular stacking of the receptor, and improve the charge mobility.

[0102] In summary, the present invention provides a non-fullerene acceptor material based on a thiophene derivative π bridge, a preparation method and application thereof. The non-fullerene acceptor material has a conjugated molecular junction of two or more π-ADA type repeating units, including three types of molecular building blocks: a thiophene derivative π bridge, an electron-donating aromatic ring core D, and an electron-withdrawing terminal unit A. The present invention can flexibly construct organic photovoltaic non-fullerene acceptor molecules by utilizing the multi-selectivity and combination of the three types of molecular building blocks. The introduction of the thiophene derivative π bridge is conducive to enhancing the DA effect, improving the degree of conjugation, and enhancing the intermolecular stacking of the acceptor, thereby improving the charge mobility. The non-fullerene acceptor material can be prepared using the more common tinization reaction and Stille coupling reaction, and has a stronger electron-donating and electron-withdrawing effect, suitable molecular stacking and higher photovoltaic performance.

[0103] 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.

[0104] 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. Non-fullerene acceptor materials based on thiophene derivative π bridges, characterized in that: A conjugated molecular junction having two or more π-ADA type repeating units, including three types of molecular building blocks: a thiophene derivative π bridge, an electron-donating aromatic ring core D, and an electron-withdrawing terminal unit A; having a structure shown in Formula I or Formula II: Wherein the π bridge is a thiophene derivative, D1, D2 and D3 are condensed aromatic units, A1 to A6 are electron-withdrawing units, n is 2 to 100, and the thiophene derivative π bridge has any structure shown in Formula III: Wherein, R1 is independently selected from C1~C 20 The alkyl group; Ar is a 6- to 14-membered aryl group or a 5- to 12-membered heteroaryl group, and the heteroatom is selected from N, O and S.

2. The non-fullerene acceptor material based on thiophene derivative π bridge according to claim 1, characterized in that: The D1, D2 and D3 have any structure shown in Formula IV: Wherein, X1 and X2 are independently selected from O, S or Se; R2, R3 and R4 are independently selected from C1~C 24 A straight chain or branched chain alkyl group.

3. The non-fullerene acceptor material based on thiophene derivative π bridge according to claim 1, characterized in that: A1-A6 has any structure shown in Formula V: Wherein, X3 and X4 are independently selected from H, F, Cl, Br, CH3, OCH3 or CN.

4. The method for preparing a non-fullerene acceptor material based on a thiophene derivative π bridge according to any one of claims 1 to 3, characterized in that: The following steps are involved: (1) The thiophene derivative is subjected to tination reaction to obtain compound a: (2) Compound a obtained in step (1) is subjected to Stille coupling reaction with the bromide b of the small molecule receptor NF under the catalytic action of a catalyst and a ligand to obtain compound c: or 。 5. The method for preparing a condensed ring-based non-fullerene electron acceptor material according to claim 4, characterized in that: In the step (1), the molar ratio of the tin compound of the thiophene derivative, the catalyst and the ligand is 1:0.03~0.1:0.6~0.2; in the step (2), the solvent of the Stille coupling reaction is selected from at least one of dioxane, toluene, xylene or chlorobenzene; the molar ratio of the small molecule receptor NF and compound b is 1:2~4; the catalyst is selected from at least one of tetrakis(triphenylphosphine)palladium, bis(triphenylphosphine)palladium dichloride, palladium acetate or tris(dibenzylideneacetone)dipalladium, and the ligand is selected from at least one of tri-tert-butylphosphine, tris(o-methylphenyl)phosphine or 4,5-bis(diphenylphosphine)-9,9-dimethylxanthene; the reaction temperature of the Stille coupling reaction is 90~140°C, and the reaction time is 6~48 hours.

6. A semiconductor material, characterized in that Contains at least one of the non-fullerene acceptor material based on a thiophene derivative π bridge according to any one of claims 1 to 3 and the non-fullerene acceptor material based on a thiophene derivative π bridge prepared by the preparation method according to claim 4 or 5.

7. A solar cell device comprising a substrate, an anode, an anode modification layer, a photoactive layer, a cathode modification layer and a cathode, characterized in that: The photoactive layer is prepared by blending the non-fullerene acceptor material based on the thiophene derivative π bridge and the electron donor material; the non-fullerene acceptor material based on the thiophene derivative π bridge is at least one of the non-fullerene acceptor material based on the thiophene derivative π bridge according to any one of claims 1 to 3, and the non-fullerene acceptor material based on the thiophene derivative π bridge prepared by the preparation method according to claim 4 or 5.

8. A solar cell device according to claim 7, characterized in that: The electron donor material is at least one of PTB7-Th, PBDB-T and PM6; the mass ratio of the electron donor material to the non-fullerene acceptor material based on the thiophene derivative π bridge in the photoactive layer is 1:1 to 1.5.

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