Non-fullerene acceptor materials based on thiophene derivative π bridge, preparation method and application thereof

Abstract

The application discloses a non-fullerene acceptor material based on a thiophene derivative pi bridge, a preparation method and application thereof. The non-fullerene acceptor material has a conjugated molecular knot with two or more than two pi-A-D-A type repeating units, and includes three types of molecular building blocks, namely, a thiophene derivative pi bridge, an aromatic ring core D with electron-donating properties, and a terminal unit A with electron-withdrawing properties. The application can flexibly construct an organic photovoltaic non-fullerene acceptor molecule by using the multi-selectivity and combination of the three types of molecular building blocks. The introduction of the thiophene derivative pi bridge is favorable for enhancing the D-A effect, improving the conjugation degree, and enhancing the intermolecular packing of the acceptor and improving the charge mobility. The non-fullerene acceptor material can be prepared by using a relatively common tin reaction and a Stille coupling reaction, has stronger electron-donating and electron-withdrawing effects, suitable molecular packing, and higher photovoltaic performance.

Description

Technical Field

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

[0002] With the increasing global demand for renewable energy, solar photovoltaic power generation, as one of the most important renewable energy sources, is attracting widespread attention. As an emerging photovoltaic technology, organic solar cells (ORCS) have shown great potential in flexible, colorful, transparent devices, and indoor photovoltaics due to their advantages such as semi-transparency, ease of processing, lightweight, and large-area fabrication (Liu et al., Advanced Materials Technologies, 2021, 6, 2000960). Thanks to advances in materials innovation and device fabrication processes, the performance of ORCS has significantly improved in recent years. In particular, the development of ADA-type non-fullerene acceptor materials has enabled small-area devices in the laboratory to achieve photoelectric conversion efficiencies exceeding 20%. ADA-type non-fullerene acceptor molecules consist of an electron-donating fused aromatic ring core (D) and an electron-withdrawing terminal unit (A). These molecules offer the advantage of modular synthesis, facilitating rapid receptor construction and performance optimization through the selection of diverse molecular building blocks. Furthermore, oligomerization or even polymerization of these ADA-type non-fullerene acceptors via π-bridges exhibits superior stability compared to small molecules. This is primarily due to the fact that this structural extension significantly increases the molecular size and effectively raises the material's 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 electron-donating π-bridge unit. 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 ability (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 polymeric non-fullerene acceptor materials based on thiophene π-bridges still lags behind that of small molecule acceptor materials. Therefore, how to introduce more excellent π-bridges to achieve improved photoelectric conversion efficiency is a technical problem that needs to be solved urgently. Summary of the Invention

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

[0004] To achieve the above objectives, in a 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 electron-donating aromatic ring core D, and an electron-withdrawing terminal unit A; 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 ring 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 Alkyl;

[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 multi-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 to A6 have 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) Thiophene derivatives are subjected to tination reaction to obtain compound a:

[0019]

[0020] (2) Compound a obtained in step (1) is subjected to a 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 above preparation method.

[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) as a connector for the acceptor, the conjugation degree of the acceptor molecule is increased, the absorption band gap of the molecule is increased, and charge transfer between and within the molecule is enhanced, which is beneficial for obtaining a large short-circuit current in an organic solar cell. Secondly, the introduction of the thiophene derivative π bridge not only forms intramolecular S...O non-covalent interactions, but also H...O non-covalent interactions, thereby enhancing the intermolecular stacking of the acceptor material and improving the carrier transport performance and fill factor of the device.

[0030] In addition, the non-fullerene acceptor material based on the thiophene derivative π bridge provided by the present invention has good film-forming properties. The material is used in solar cells. After device fabrication 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 an example of the present invention.

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

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

[0035] The technical solutions in the embodiments will be described clearly and completely below. Obviously, the embodiments described below are only a 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 losing any hydrogen atom of an alkane compound, and the alkane compound includes straight-chain alkanes, branched-chain 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 the structure shown in Formula I or Formula II:

[0039]

[0040] Wherein the π bridge is a thiophene derivative, D1, D2 and D3 are condensed ring 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. 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 ring 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 Alkyl;

[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] Said 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 bridges is beneficial to enhance the DA effect, increase 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 Example 1, comprising the following steps:

[0060] (1) Thiophene derivatives are subjected to tination reaction to obtain compound a:

[0061]

[0062] (2) Compound a obtained in step (1) is subjected to a 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, 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.

[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 relatively common tinization 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 readily available 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 acceptor material X-1. The synthetic route of the acceptor 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 round-bottom flask. Then, n-butyl lithium (5.2 ml, 2.4 M) was slowly added dropwise at -78°C. The reaction mixture was allowed to react at this temperature for 1 hour. Trimethyltin chloride (1 M) was then added and the reaction continued for another hour. After completion, the reaction was quenched with water and extracted with ether. The organic phase was dried over anhydrous sodium sulfate and then spin-dried to obtain the crude product. The product was then recrystallized from ethanol to yield compound 2 (white solid, 1.5 g, 66%). H NMR (400 MHz, 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] To a 50ml round-bottom flask, compound 2 (100mg), compound 3 (862mg), and toluene (20ml) were added. After bubbling nitrogen for 15 minutes, tetrakistriphenylphosphine palladium (5mg) was added and the mixture was allowed to react at 110°C for 12 hours. After completion of the reaction, water was added to quench the reaction and the mixture was extracted with chloroform. The organic phase was dried over anhydrous sodium sulfate and then spin-dried to obtain a crude product. The crude product 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 2 As shown in the UV absorption spectrum Figure 3 shown.

[0077] Example 2: Preparation of Acceptor Material X-2

[0078] In a 50ml round-bottom flask, compound 4 (200mg), compound 2 (50mg), and toluene (20ml) were added. After bubbling nitrogen for 15 minutes, tris(dibenzylideneacetone)dipalladium (5mg) and tris(o-methylphenyl)phosphine (10mg) were added and reacted at 110°C for 12 hours. After completion of the reaction, water was added to quench the reaction, and the mixture was extracted with chloroform. The organic phase was dried over anhydrous sodium sulfate, concentrated, and then precipitated in methanol to obtain receptor X-2 (178mg, 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] To a 50ml round-bottom flask, compound 2 (100mg), compound 3 (862mg), and toluene (20ml) were added. After bubbling nitrogen for 15 minutes, tetrakistriphenylphosphine palladium (5mg) was added and the mixture was allowed to react at 110°C for 12 hours. After completion of the reaction, water was added to quench the reaction and the mixture was extracted with chloroform. The organic phase was dried over anhydrous sodium sulfate and then spin-dried to obtain a crude product. The crude product was separated and purified by silica gel column chromatography (eluent: chloroform: petroleum ether = 1:1, v / v) to obtain receptor X-1 (627mg, 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 2 As shown in the UV absorption spectrum Figure 3 shown.

[0085] S1 is a thiophene-bridged non-fullerene acceptor material, and X-1 is a thiophene derivative π-bridged non-fullerene acceptor material. Their thin film UV absorption spectra are shown in the attached Figure 3 Compared with the acceptor material S1, X-1 has a strong and narrow absorption in the wavelength range of 750~850nm, and the maximum absorption peak is slightly red-shifted. This shows 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 Example 1 and the non-fullerene acceptor material based on a thiophene derivative π bridge prepared by the preparation method described in Example 2.

[0088] Example 4

[0089] This 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 a 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)]), and 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 to 20 mg / mL, preferably 5 to 10 mg / mL, and the concentration of the electron acceptor can be 1.5 to 30 mg / mL, preferably 5 to 15 mg / mL. The photoactive layer is annealed at a temperature of 50 to 150° C. for 1 to 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 utilizes an upright device structure, specifically a glass substrate / ITO / PEDOT:PSS / PBDB-T:X-1 / PFN-Br / silver. The ITO layer is attached to the glass substrate. The ITO and glass substrate are collectively referred to as ITO glass. The ITO glass is ultrasonically washed with detergent, water, acetone, and isopropyl alcohol for 30 minutes each. It is then oven-dried at 90°C overnight. After the ITO glass is treated with UV-ozone for 15 minutes, PEDOT:PSS is spin-coated on the ITO layer and heated in a 140°C oven for 15 minutes before being quickly transferred to a glove box for later 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% 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% melamine by mass) was spin-coated on the active layer. Finally, the negative electrode of the battery was placed in a vacuum of about 1×10 -4 The device is completed by thermal evaporation of 150nm silver electrodes 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 SourceMeter instrument.

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

[0098] Compared to the solar cell prepared based on the comparative example, the solar cell based on Example 1 exhibited higher device performance, demonstrating that the modification with the thiophene derivative in Example 1 indeed improves the efficiency of both intermolecular and intramolecular charge transfer, thereby comprehensively enhancing cell performance. Furthermore, the non-fullerene acceptor material X-1, based on the thiophene derivative π bridge, exhibits excellent film-forming properties. After device fabrication and optimization, the material was used in solar cells, achieving a conversion efficiency exceeding 18%. Furthermore, the cell exhibited an open-circuit voltage exceeding 0.92 volts and a short-circuit current exceeding 25 mA / 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] The test results of the above embodiments and application examples indicate 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 bridges is beneficial for enhancing the DA effect, increasing the degree of conjugation, and enhancing the intermolecular stacking of the receptor, thereby improving charge mobility.

[0102] In summary, the present invention provides a non-fullerene acceptor material based on a thiophene derivative π bridge, its preparation method, and application. The non-fullerene acceptor material comprises a conjugated molecular structure of two or more π-ADA repeating units, comprising three molecular building blocks: a thiophene derivative π bridge, an electron-donating aromatic ring core D, and an electron-withdrawing terminal unit A. By utilizing the multi-selectivity and combination of these three molecular building blocks, the present invention enables the flexible construction of organic photovoltaic non-fullerene acceptor molecules. The introduction of the thiophene derivative π bridge enhances the DA effect, increases the degree of conjugation, and enhances the intermolecular stacking of the acceptor, thereby improving charge mobility. The non-fullerene acceptor material can be prepared using the relatively common tination reaction and Stille coupling reaction, and exhibits stronger electron-donating and electron-withdrawing interactions, suitable molecular stacking, and high photovoltaic performance.

[0103] Those skilled in the art should understand that they can implement variations by combining the prior art with the above embodiments, which will not be described in detail here. Such variations do not affect the essence 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-mentioned 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 that do not depart 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 by: 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 ring aromatic units, A1 to A6 are electron-withdrawing units, n is 2 to 100, and the π bridge has any structure shown in Formula III: ， Wherein, R1 is independently selected from C1~C 20 Alkyl; Ar is a 6- to 14-membered aryl group or a 5- to 12-membered heteroaryl group, wherein the heteroatom is selected from N, O, and S; The D1, D2 and D3 have the structure shown in Formula IV: ， In formula IV, X1 and X2 are independently selected from O, S or Se; R2 and R3 are independently selected from C1~C 24 A straight or branched chain alkyl group; Said A1 and A4 have the structure shown in Formula V: ， In Formula V, X3 is independently selected from H, F, Cl, Br, CH3, OCH3 or CN; Said A2, A3, A5 and A6 have the structure shown in Formula VI: ， In Formula VI, X3 and X4 are independently selected from H, F, Cl, Br, CH3, OCH3 or CN.

2. A semiconductor material, characterized in that A non-fullerene acceptor material based on a thiophene derivative π bridge according to claim 1.

3. 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 the non-fullerene acceptor material based on the thiophene derivative π bridge according to claim 1.

4. A solar cell device according to claim 3, 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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