Polymer containing thieno [3, 4-b] thiophene and application thereof

Abstract

The invention relates to the technical field of organic photovoltaic cell materials, in particular to a thieno [3, 4-b] thiophene-containing polymer and application thereof. When # imgabs0 # imgabs1 # is introduced into a polymer repeating unit to serve as a donor material to be matched with a proper acceptor material to be applied to a semitransparent organic photovoltaic device, better photoelectric conversion efficiency and transmissivity are obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of organic photovoltaic cell materials, and in particular to a polymer containing thieno[3,4-b]thiophene and applications thereof. Background Art

[0002] With the increasing global demand for renewable energy, developing high-performance solar photovoltaic technology is an effective way to address energy and environmental issues. Compared to traditional silicon-based photovoltaics and emerging perovskite photovoltaic technologies, the organic semiconductor materials used in organic photovoltaic cells (OPV) have attracted widespread attention from researchers due to their advantages such as light weight, high absorption coefficient, easy structural adjustment, and ease of purification. Currently, by selecting organic semiconductor materials with different band gaps, semi-transparent organic photovoltaic cells can be prepared that absorb light energy mainly in the near-infrared and ultraviolet bands and allow a moderate amount of visible light to pass through. Semi-transparent OPV can be used in application scenarios such as building integrated photovoltaics (BIPV), on-board energy systems, agricultural photovoltaic greenhouses, and smart dimming windows.

[0003] Current research in semi-transparent organic photovoltaic cells focuses on balancing the relationship between photon conversion efficiency (PCE) and average visible light transmittance (AVT), while maximizing light utilization efficiency (LUE). Active layer engineering is an effective approach to addressing this balance. An ideal semi-transparent organic solar cell active layer should allow the transmission of a significant portion of visible light photons to achieve high visible light transmittance, while maximizing the absorption and utilization of photons in the non-visible region (near-ultraviolet and near-infrared) to achieve high energy conversion. This means selectively absorbing and utilizing the entire solar spectrum, thereby achieving an optimal balance between optical and electrical performance. Developing active layer materials with near-infrared absorption is one of the most effective strategies for improving the performance of semi-transparent organic solar cells. With the rapid development of active layer electron acceptor materials in recent years, the optoelectronic performance of semi-transparent organic solar cells has also rapidly improved. However, with respect to electron donor materials, the development of efficient polymer donor materials suitable for semi-transparent organic photovoltaic cells is relatively lagging. Therefore, further development of efficient polymer donor materials is crucial for advancing the technological development of semi-transparent organic photovoltaic cells. Summary of the Invention

[0004] Based on this, in order to address the deficiencies of the prior art, the present invention aims to provide a polymer containing thieno[3,4-b]thiophene, which can be used as a photoactive layer donor material in semi-transparent organic photovoltaic devices to improve the performance of the device.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A polymer containing thieno[3,4-b]thiophene has a structure as shown in formula (I):

[0007]

[0008] in:

[0009] Each occurrence of Y is independently selected from O, S or Se;

[0010] Each occurrence of Z is independently selected from O or S;

[0011] Each occurrence of R1 is independently selected from -H, -D, -F, -Cl, -Br, -I, -CN or -CF3;

[0012] R2, at each occurrence, is independently selected from a straight chain alkyl group having 1 to 20 carbon atoms, or a branched chain alkyl group having 3 to 20 carbon atoms;

[0013] R3, R4, R5, R6, each occurrence, is independently selected from -H, -D, -F, -Cl, -Br, -I, -CN, -CF3, a straight-chain alkyl group having 1-20 carbon atoms, a branched-chain alkyl group having 3-20 carbon atoms, a straight-chain alkoxy group having 1-20 carbon atoms, a branched-chain alkoxy group having 3-20 carbon atoms, a straight-chain alkylthio group having 1-20 carbon atoms, or a branched-chain alkylthio group having 3-20 carbon atoms;

[0014] Each occurrence of R7 is independently selected from a straight chain alkyl group having 1 to 20 carbon atoms, a branched chain alkyl group having 3 to 20 carbon atoms, a * A substituted or unsubstituted aromatic group having 6 to 20 carbon atoms, or a * a substituted or unsubstituted heteroaromatic group having 5 to 20 ring atoms;

[0015] R * Each occurrence is independently selected from -D, -F, -Cl, -Br, -I, -CN, -CF3, a straight-chain alkyl group having 1-20 carbon atoms, a branched-chain alkyl group having 3-20 carbon atoms, a straight-chain alkoxy group having 1-20 carbon atoms, a branched-chain alkoxy group having 3-20 carbon atoms, a straight-chain alkylthio group having 1-20 carbon atoms, or a branched-chain alkylthio group having 3-20 carbon atoms;

[0016] R8, at each occurrence, is independently selected from -H, -D, -F, -Cl, -Br, -I, -CN, -CF3, a straight-chain alkyl group having 1-20 carbon atoms, a branched-chain alkyl group having 3-20 carbon atoms, a straight-chain alkoxy group having 1-20 carbon atoms, a branched-chain alkoxy group having 3-20 carbon atoms, a straight-chain alkylthio group having 1-20 carbon atoms, or a branched-chain alkylthio group having 3-20 carbon atoms;

[0017] n is the number of repeating units, and n is an integer selected from 1 to 10,000.

[0018] Formula (I) of the present invention The polymer containing thieno[3,4-b]thiophene comprises repeating units With repeating units described and The copolymerization is random copolymerization. That is, the polymer containing thieno[3,4-b]thiophene described in the present invention is a random polymer consisting of repeating units. and repeating units Random copolymerization.

[0019] Furthermore, the polymer containing thieno[3,4-b]thiophene has a structure as shown in formula (II-1) or (II-2):

[0020]

[0021] In one embodiment, Y is selected from S.

[0022] In one embodiment, each occurrence of R1 is independently selected from -H, -F or -Cl.

[0023] In one embodiment, each occurrence of R2 is independently selected from a linear alkyl group having 1 to 10 carbon atoms, or a branched alkyl group having 3 to 10 carbon atoms.

[0024] Furthermore, each occurrence of R2 is independently selected from methyl, ethyl, -C4H9, -C6H 13 、-C8H 17 、

[0025] Where: * indicates the connection site.

[0026] In a specific embodiment, Selected from the following groups:

[0027]

[0028] Understandably, is the corresponding unit in formula (I), formula (II-1) or (II-2).

[0029] In one embodiment, each occurrence of R7 is independently selected from a linear alkyl group having 1 to 20 carbon atoms, a branched alkyl group having 3 to 20 carbon atoms, a * Substituted or unsubstituted phenyl, or R * a substituted or unsubstituted thienyl group.

[0030] Furthermore, the R *Each occurrence is independently selected from -D, -F, -Cl, -Br, -I, -CN, -CF3, a straight-chain alkyl group having 1 to 10 carbon atoms, a branched-chain alkyl group having 3 to 10 carbon atoms, a straight-chain alkoxy group having 1 to 10 carbon atoms, a branched-chain alkoxy group having 3 to 10 carbon atoms, a straight-chain alkylthio group having 1 to 10 carbon atoms, or a branched-chain alkylthio group having 3 to 10 carbon atoms.

[0031] Further, each of the R7 is independently selected from phenyl, -C6H 13 、-C8H 17 、

[0032] In one embodiment, each occurrence of R8 is independently selected from -H, or -F.

[0033] In a specific embodiment, the Selected from the following groups:

[0034]

[0035] Understandably, is the corresponding unit in formula (II-1).

[0036] In a specific embodiment, the Selected from the following groups:

[0037]

[0038] Understandably, is the corresponding unit in formula (II-2).

[0039] In one embodiment, each occurrence of R3, R4, R5, and R6 is independently selected from -H, -D, -F, -Cl, -Br, -I, -CN, -CF3, a straight-chain alkyl group having 1-10 carbon atoms, a branched-chain alkyl group having 3-10 carbon atoms, a straight-chain alkoxy group having 1-10 carbon atoms, a branched-chain alkoxy group having 3-10 carbon atoms, a straight-chain alkylthio group having 1-10 carbon atoms, or a branched-chain alkylthio group having 3-10 carbon atoms.

[0040] Furthermore, each occurrence of R3, R4, R5, and R6 is independently selected from -H, -C6H 13 、-C8H 17 、 -F or -Cl.

[0041] In a specific embodiment, the polymer containing thieno[3,4-b]thiophene according to the present invention is selected from the following structures but is not limited thereto:

[0042]

[0043]

[0044] In one embodiment, according to the polymer containing thieno[3,4-b]thiophene of the present invention, the number average molecular weight (Mn) of the polymer is selected from 10,000-1,000,000.

[0045] Furthermore, the number average molecular weight (Mn) of the polymer is between 20,000 and 1,000,000.

[0046] Furthermore, the number average molecular weight (Mn) of the polymer is between 20,000 and 50,000.

[0047] The present invention further relates to a mixture comprising a polymer containing thieno[3,4-b]thiophenes as described above.

[0048] Furthermore, the mixture comprises an electron donor material and an electron acceptor material, wherein the electron donor material is selected from the polymer containing thieno[3,4-b]thiophene as described above; and the electron acceptor material is selected from one or more of fullerene acceptor materials and non-fullerene acceptor materials.

[0049] The fullerene acceptor material is selected from C60 or C70 or its derivatives, such as PC 61 BM, PC 71 BM.

[0050] The non-fullerene acceptor material is selected from any of the following structures, but is not limited thereto:

[0051]

[0052]

[0053] In an optional embodiment, the mass ratio of the electron donor material to the electron acceptor material in the mixture is selected from 2:1 to 1:2.

[0054] Furthermore, the mass ratio of the electron donor material to the electron acceptor material in the mixture is selected from 1:1 to 1:2.

[0055] The present invention further relates to a composition comprising the polymer or mixture containing thieno[3,4-b]thiophenes as described above, and at least one organic solvent.

[0056] In some optional embodiments, the organic solvent is selected from but not limited to: tetralin, 1,5-dimethyltetrahydrofuran, methyltetrahydrofuran, decahydronaphthalene, chlorobenzene, o-dichlorobenzene, 1,2,4-trichlorobenzene, 1,4-dimethylnaphthalene, toluene, o-xylene, m-xylene, p-xylene, mesitylene, o-diethylbenzene, m-diethylbenzene, p-diethylbenzene, 1,2,3,4-tetramethylbenzene, 1,2,3,5-tetramethylbenzene, 1,2,4,5-tetramethylbenzene, acetophenone, diphenyl ether, 2-methylthiophene, 3-methylthiophene, chloromethane, dichloromethane, chloroform, dichloroethylene, trichloromethane, Ethylene, 1,2-trichlorotrifluoroethane, 1,2-dichloroethane, 1,1,1-trichloroethane, 1,1,2,2-tetrachloroethane, carbon tetrachloride, tetrahydrofuran, anisole, 2,4-dimethylanisole, 1-methylnaphthalene, morpholine, 1,4-dioxane, N-methylpyrrolidone, acetone, cyclopentanone, cyclohexanone, methyl ethyl ketone, ethyl acetate, n-butyl acetate, carbon disulfide, carbon tetrachloride, N,N-dimethylformamide, dimethylacetamide, dimethyl sulfoxide, indane, methyl benzoate, ethyl benzoate, acetonitrile, hexamethylphosphoramide, or a mixed solvent of two or more.

[0057] In some optional embodiments, the organic solvent is selected from but not limited to chlorobenzene, toluene, o-xylene, or chloroform.

[0058] In some optional embodiments, the composition further comprises additives for adjusting viscosity, adjusting film-forming properties, and improving adhesion.

[0059] In some optional embodiments, the additive is selected from but not limited to 1,8-diiodooctane, diphenyl ether, anthracene, 1,4-diiodobenzene, 1,3-dibromo-5-chlorobenzene, 3,5-dichlorobromobenzene, 1-chloronaphthalene, and 1,3,5-tribromobenzene.

[0060] The present invention also provides an organic photovoltaic cell, comprising an anode, a cathode, and a photoactive layer located between the anode and the cathode, wherein the photoactive layer comprises the aforementioned polymer containing thieno[3,4-b]thiophene, the aforementioned mixture, or is prepared from the aforementioned composition.

[0061] In some optional embodiments, the photoactive layer can be prepared by dissolving a photoactive layer donor material and an acceptor material in an organic solvent to obtain a photoactive layer solution, and using the photoactive layer solution to prepare the photoactive layer by printing or coating. The donor material is selected from the aforementioned polymer containing thieno[3,4-b]thiophene; and the acceptor material is selected from one or more of a fullerene acceptor material and a non-fullerene acceptor material.

[0062] In some optional embodiments, the printing or coating preparation method can be, but is not limited to, inkjet printing, gravure printing, spray printing, letterpress printing, screen printing, dip coating, spin coating, doctor blade coating, roller printing, twist roller printing, offset printing, flexographic printing, rotary printing, spray coating, brush coating, pad printing, slot extrusion coating, etc.

[0063] In one embodiment, the anode and cathode may be made of a transparent or semi-transparent conductive material, but is not limited thereto. The conductive material can be a conductive metal oxide, such as indium oxide, zinc oxide, tin oxide, indium tin oxide (ITO), fluorine-doped tin oxide (FTO), gallium-doped zinc oxide (GZO), aluminum-doped zinc oxide (AZO), indium zinc oxide (IZO) and indium gallium zinc oxide (IGZO); conductive polymers, such as poly(3,4-ethylenedioxythiophene) / poly(4-styrenesulfonate) (PEDOT / PSS), polypyrrole and polyaniline; conductive carbon materials, such as graphene, carbon nanotubes, etc.; nanoconductive materials, such as metal nanoparticles or nanowires, etc.; ultra-thin metal layers capable of maintaining a certain transmittance and composite stacks containing the same, such as metal layers formed of metals such as gold, platinum, silver, copper, cobalt, nickel, indium or aluminum, or film stacks containing alloys of any of these metals; ultra-thin metal layers capable of maintaining a certain transmittance and composite stacks with metal oxides, such as MoO3 and Ag composite stacks, MoO3 and Cu and Ag composite stacks, etc.

[0064] In some optional embodiments, the organic photovoltaic cell is stacked with an anode, an anode buffer layer, a photoactive layer, a cathode buffer layer and a cathode in sequence from bottom to top, and the photoactive layer comprises the above-mentioned thieno[3,4-b]thiophene-containing polymer, the above-mentioned mixture, or is prepared from the above-mentioned composition.

[0065] In some optional embodiments, the cathode buffer layer material can be selected from metal complexes, metal oxides, metal salts, etc. with low work function, such as metal complexes of 8-hydroxyquinoline, complexes containing Alq3, metal complexes containing Liq, LiF, Ca, titanium oxide (TiO x ), zinc oxide (ZnO), cesium carbonate (Cs2CO3), etc.; it can also be a polymer material, such as PFN-Br or PFN or PDINN or PDINO or PNDIT-F3N-Br or PNDIT-F3N, etc., but not limited to this.

[0066] In some optional embodiments, the anode buffer layer material is selected from PEDOT:PSS, molybdenum oxide (MoO x ), vanadium oxide (V2O5), nickel oxide (NiO), tungsten oxide (WO x), small molecule self-assembly materials such as 2PACz, MeO-2PACz, etc., but not limited thereto.

[0067] It should be noted that, in order to improve the performance of the organic photovoltaic cell, the organic photovoltaic cell may further comprise other functional layers, including but not limited to a charge blocking layer, a charge transport layer or a passivation layer.

[0068] In some optional embodiments, the organic photovoltaic cell further comprises a substrate.

[0069] In some optional embodiments, the substrate is disposed on one side of the anode and on a different side from the photoactive layer.

[0070] In another embodiment, the substrate is disposed on one side of the cathode and on a different side from the photoactive layer.

[0071] In some optional embodiments, as the substrate, a substrate having excellent transparency, surface smoothness, ease of handling and water resistance can be used. Specifically, a glass substrate, a film glass substrate or a transparent plastic substrate can be used. The plastic substrate can include a film in the form of a single layer or multiple layers, such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyetheretherketone (PEEK), polyimide (PI), polyparaxylene (Parylene), etc., but is not limited thereto, and substrates commonly used for organic photovoltaic cells can also be used.

[0072] In an optional embodiment, the organic photovoltaic cell according to the present invention is a semi-transparent organic photovoltaic cell.

[0073] The present invention also provides that the organic photovoltaic cell is mainly used in outdoor photovoltaics, such as building photovoltaics, vehicle photovoltaics, agricultural photovoltaics and smart windows.

[0074] Beneficial effects of the present invention:

[0075] The present invention introduces The group has strong electron-donating properties. The group has strong electron-withdrawing properties. Both units are asymmetric, which can cause local irregularities in the polymer region, improving the polymer's solubility, processability, and near-infrared absorption. When used as a donor material in combination with a suitable acceptor material in semi-transparent organic photovoltaic devices, it achieves good photoelectric conversion efficiency and transmittance. BRIEF DESCRIPTION OF THE DRAWINGS

[0076] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0077] Figure 1 This is the GPC spectrum of the polymer (P31) described in Polymer Synthesis Example 8.

[0078] Figure 2 It is a schematic structural diagram of an embodiment of an organic photovoltaic device (OPV) device of the present invention. DETAILED DESCRIPTION

[0079] The following examples are provided for a better understanding of the present invention and are not intended to limit the best mode of implementation. They do not limit the content and scope of protection of the present invention. Any product identical or similar to the present invention obtained by anyone under the guidance of the present invention or by combining the features of the present invention with other prior arts shall fall within the scope of protection of the present invention.

[0080] The terms "and / or", "or / and", and "and / or" used herein include any one of two or more related listed items, and also include any and all combinations of the related listed items, wherein the arbitrary and all combinations include any combination of two related listed items, any more related listed items, or all related listed items. It should be noted that when at least three items are connected by at least two conjunctions selected from "and / or", "or / and", and "and / or", it should be understood that in this application, the technical solution undoubtedly includes technical solutions connected by "logical and" and also undoubtedly includes technical solutions connected by "logical or". For example, "A and / or B" includes three parallel solutions of A, B and A+B. For example, the technical solution of "A, and / or, B, and / or, C, and / or, D" includes any one of A, B, C, and D (that is, the technical solution of all being connected by "logical OR"), and also includes any and all combinations of A, B, C, and D, that is, the combination of any two or any three of A, B, C, and D, and also includes the four-item combination of A, B, C, and D (that is, the technical solution of all being connected by "logical AND").

[0081] In the present invention, organic photovoltaic device, organic solar cell, OPV and OSC have the same meaning and can be interchanged.

[0082] In the present invention, photoactive layer and active layer have the same meaning and can be interchanged.

[0083] In the present invention, when a group contains multiple substituents with the same symbol, the substituents may be the same or different from each other, for example The six Rs on the benzene ring may be the same as or different from each other.

[0084] In the present invention, the "number of ring atoms" refers to the number of atoms among the atoms constituting the ring itself of a structural compound (e.g., a monocyclic compound, a condensed ring compound, a cross-linked compound, a carbocyclic compound, a heterocyclic compound) formed by atoms bonding to form a ring. When the ring is substituted by a substituent, the atoms contained in the substituent are not included in the ring atoms. The same applies to the "number of ring atoms" described below unless otherwise specified. In an aromatic group, the number of ring atoms is the same as the number of carbon atoms; in a heteroaromatic group, the number of ring atoms is the number of carbon atoms plus the number of heteroatoms; for example, the number of ring atoms of a benzene ring is 6, the number of ring atoms of a naphthalene ring is 10, the number of ring atoms of a quinoline ring is 10, the number of ring atoms of a thienyl group is 5, and the number of ring atoms of a thienothiophene group is 8.

[0085] In the present invention, "aromatic group" refers to an optional functional group or substituent derived from an aromatic carbocyclic ring. The aromatic group can be a monocyclic aromatic group (e.g., phenyl) or a polycyclic aromatic group. In other words, the aromatic group can be a monocyclic aromatic group, a condensed ring aromatic group, two or more monocyclic aromatic groups connected by carbon-carbon conjugation, a monocyclic aromatic group and a condensed ring aromatic group connected by carbon-carbon conjugation, or two or more condensed ring aromatic groups connected by carbon-carbon conjugation. That is, unless otherwise indicated, two or more aromatic groups connected by carbon-carbon conjugation can also be considered as aromatic groups of the present application. Aromatic groups include, but are not limited to, phenyl, biphenyl, terphenyl, naphthyl, and derivatives thereof.

[0086] In the present invention, "heteroaromatic group" refers to a monovalent heteroaromatic ring or derivative thereof containing 1, 2, 3, 4, 5, 6 or more heteroatoms in the ring, wherein the heteroatom can be at least one of B, O, N, P, Si, Se and S. The heteroaromatic group can be a monocyclic heteroaromatic group or a polycyclic heteroaromatic group. In other words, the heteroaromatic group can be a single heteroaromatic ring system or multiple heteroaromatic ring systems connected by carbon-carbon bonds, and any heteroaromatic ring system is a heteroaromatic monocyclic ring or a heteroaromatic fused ring. Heteroaromatic groups include, but are not limited to, thienyl, furyl, selenophenyl, thienothiphenyl, thienoselenophenyl, pyridyl, pyrimidinyl, triazinyl and their derivatives.

[0087] In the present invention, the number of carbon atoms of a straight-chain alkyl group may be C1-C20, C1-C16, C1-C10, or C1-C6. The number of carbon atoms of a branched-chain alkyl group may be C3-C20, C3-C16, C3-C10, or C3-C6. The number of carbon atoms of a cycloalkyl group may be C3-C20, C3-C16, C3-C10, or C3-C6. Non-limiting examples of straight-chain alkyl groups include methyl (-CH3), ethyl (-C2H5), n-propyl (-C3H7), n-butyl (-C4H9), n-pentyl (-C5H 11 ), n-hexyl (-C6H 13 ), n-heptyl (-C7H 15 ), n-octyl (-C8H 17 ), n-nonyl (-C9H 19 ),-C 10 H 21 、-C 11 H 23 、-C 12 H 25 、-C 13 H 27 、-C 14 H 29 、-C 15 H 31 、-C 16 H 33 Non-limiting examples of branched alkyl groups include isopropyl, branched alkyl groups containing 4 C atoms, branched alkyl groups containing 5 C atoms, branched alkyl groups containing 6 C atoms, branched alkyl groups containing 7 C atoms, branched alkyl groups containing 8 C atoms, branched alkyl groups containing 9 C atoms, branched alkyl groups containing 10 C atoms, branched alkyl groups containing 11 C atoms, branched alkyl groups containing 12 C atoms, branched alkyl groups containing 13 C atoms, branched alkyl groups containing 14 C atoms, branched alkyl groups containing 15 C atoms, and branched alkyl groups containing 16 C atoms. Non-limiting examples of cycloalkyl groups include: cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloalkyl groups containing 7 C atoms, cycloalkyl groups containing 8 C atoms, cycloalkyl groups containing 9 C atoms, cycloalkyl groups containing 10 C atoms (such as adamantyl), cycloalkyl groups containing 11 C atoms, cycloalkyl groups containing 12 C atoms, cycloalkyl groups containing 13 C atoms, cycloalkyl groups containing 14 C atoms, cycloalkyl groups containing 15 C atoms, and cycloalkyl groups containing 16 C atoms.

[0088] The term "alkoxy" refers to a group having the structure "-O-alkyl," i.e., an alkyl group as defined above attached to another group via an oxygen atom. A linear alkoxy group refers to a group in which the alkyl group in the "-O-alkyl" group is selected from a linear alkyl group, wherein the carbon atoms of the linear alkyl group may be C1-C20, C1-C16, C1-C10, or C1-C6; a branched alkoxy group refers to a group in which the alkyl group in the "-O-alkyl" group is selected from a branched alkyl group, wherein the number of carbon atoms of the branched alkyl group may be C3-C20, C3-C16, C3-C10, or C3-C6.

[0089] The term "alkylthio" refers to a group having the structure "-S-alkyl," i.e., an alkyl group as defined above attached to another group via a sulfur atom. A linear alkylthio group means that the alkyl group in the "-S-alkyl" group is selected from a linear alkyl group, wherein the carbon atoms of the linear alkyl group may be C1-C20, C1-C16, C1-C10, or C1-C6; a branched alkylthio group means that the alkyl group in the "-S-alkyl" group is selected from a branched alkyl group, wherein the number of carbon atoms of the branched alkyl group may be C3-C20, C3-C16, C3-C10, or C3-C6.

[0090] In the present invention, one or more groups “independently selected” means that when one or more groups appear simultaneously in multiple places in a compound, they are all independently selected and may be the same or different.

[0091] In the present invention, the single bond connecting the substituent runs through the corresponding ring, indicating that the substituent can be connected to any position of the ring, for example R is connected to any substitutable position of the benzene ring.

[0092] In the process of describing the structural elements of the present invention, the words "include" or "comprises" and the like used in the present invention mean that the devices or materials preceding the word include the devices or materials listed after the word and their equivalents, without excluding other devices or materials.

[0093] In the description of the present invention, it should be understood that the terms "upper", "lower", "between layers", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which organic solar cell devices are conventionally placed when in use, or are the orientations or positional relationships conventionally understood by those skilled in the art. These terms are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, they should not be understood as limiting the present invention.

[0094] The terms "combination thereof", "any combination thereof", "any combination thereof", "combination" and the like used in the present invention include all suitable combinations of any two, any three or more of the listed groups.

[0095] In the present invention, “further”, “further”, “particularly”, etc. are used for descriptive purposes to indicate differences in content, but should not be understood as limiting the scope of protection of the present invention.

[0096] In the present invention, the terms "optionally," "optional," and "optional" mean optional or dispensable, i.e., they refer to either option being selected from two parallel options: "with" or "without." If a technical solution contains multiple "optional" clauses, each "optional" clause is independent unless otherwise specified and there are no conflicts or constraints.

[0097] In the present invention, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0098] Polymer Synthesis Examples

[0099] The following examples are provided to facilitate a better understanding of the disclosure of the present invention and are not intended to limit the present invention in any way. The experimental methods used in the following examples are conventional methods unless otherwise specified, and the materials and reagents used are all prior art and can be obtained from commercial sources unless otherwise specified.

[0100] Synthesis of monomer M1:

[0101]

[0102] Synthesis of compound 1-3:

[0103] Accurately weigh compound 1-1 (908 mg, 2 mmol), compound 1-2 (2239 mg, 6 mmol), and toluene (20 mL) were added to a 50 mL three-necked flask, the nitrogen atmosphere was replaced three times, tetrakistriphenylphosphine palladium (116 mg, 0.1 mmol) was added, the nitrogen atmosphere was replaced twice, and the mixture was heated to 90 ° C for 3 h. The reaction was monitored by TLC. After the reaction was completed, water was added to quench the reaction, and the mixture was extracted with ethyl acetate. The organic phase was dried over anhydrous sodium sulfate, and the excess solvent was distilled off under reduced pressure. The sample was mixed with silica gel for column chromatography, and the eluent was PE:DCM = 5:1 (v / v) to obtain approximately 694 mg of compound 1-3, with a yield of 75.3%, and MS: 460.92.

[0104] Synthesis of monomer M1:

[0105] Compound 1-3 (461 mg, 1 mmol) and DMF (10 mL) were accurately weighed and added sequentially into a 50 mL three-necked flask, and NBS (534 mg, 3 mmol) was added in batches. The temperature was then raised to 80°C and allowed to react overnight. After the reaction was complete, water was added to quench the reaction, and the mixture was extracted with ethyl acetate. The organic phase was dried over anhydrous sodium sulfate, and the excess solvent was removed by distillation under reduced pressure. The mixture was recrystallized from ethanol to obtain approximately 425 mg of monomer M1 with a yield of 68.7% and MS: 618.63.

[0106] Synthesis of monomer M2:

[0107]

[0108] Synthesis of compound 2-3:

[0109] Accurately weigh compound 2-1 (944 mg, 2 mmol), compound 2-2 (2744 mg, 6 mmol), and toluene (20 mL) were added to a 50 mL three-necked flask in sequence, the nitrogen atmosphere was replaced three times, tetrakistriphenylphosphine palladium (116 mg, 0.1 mmol) was added, the nitrogen atmosphere was replaced twice, and the mixture was heated to 90 ° C for 3 h. The reaction was monitored by TLC. After the reaction was completed, water was added to quench the reaction, and the mixture was extracted with ethyl acetate. The organic phase was dried over anhydrous sodium sulfate, and the excess solvent was distilled off under reduced pressure. The sample was mixed with silica gel and subjected to column chromatography with an eluent of PE:DCM = 5:1 (v / v) to obtain approximately 786 mg of compound 2-3, a yield of 60.8%, and MS: 646.85.

[0110] Synthesis of monomer M2:

[0111] Accurately weigh compound 2-3 (647 mg, 1 mmol) and DMF (10 mL) were added sequentially into a 50 mL three-necked flask, and NBS (534 mg, 3 mmol) was added in batches. The temperature was then raised to 80°C and reacted overnight. After the reaction was complete, water was added to quench the reaction, and the mixture was extracted with ethyl acetate. The organic phase was dried over anhydrous sodium sulfate, and the excess solvent was removed by distillation under reduced pressure. The mixture was recrystallized from ethanol to obtain approximately 615 mg of monomer M2 with a yield of 76.5% and MS: 804.36.

[0112] Synthesis of monomer M3:

[0113]

[0114] Synthesis of compound 3-2:

[0115] Accurately weigh compound 2-1 (944 mg, 2 mmol), compound 3-1 (2347 mg, 6 mmol), and toluene (20 mL) were added to a 50 mL three-necked flask in sequence, the nitrogen atmosphere was replaced three times, tetrakistriphenylphosphine palladium (116 mg, 0.1 mmol) was added, the nitrogen atmosphere was replaced twice, and the mixture was heated to 90 ° C for 3 h. The reaction was monitored by TLC. After the reaction was completed, water was added to quench the reaction, and the mixture was extracted with ethyl acetate. The organic phase was dried over anhydrous sodium sulfate, and the excess solvent was distilled off under reduced pressure. The sample was mixed with silica gel for column chromatography, and the eluent was PE:DCM = 5:1 (v / v) to obtain about 698 mg of compound 3-2, a yield of 67.8%, and MS: 514.97.

[0116] Synthesis of monomer M3:

[0117] Accurately weigh compound 3-2 (515 mg, 1 mmol) and DMF (10 mL) were added sequentially into a 50 mL three-necked flask, and NBS (534 mg, 3 mmol) was added in batches. The temperature was then raised to 80°C and reacted overnight. After the reaction was complete, water was added to quench the reaction, and the mixture was extracted with ethyl acetate. The organic phase was dried over anhydrous sodium sulfate, and the excess solvent was removed by distillation under reduced pressure. The mixture was recrystallized from ethanol to obtain approximately 546 mg of monomer M3 with a yield of 81.3% and MS: 671.88.

[0118] Synthesis of monomer M4:

[0119]

[0120] Synthesis of compound 4-2:

[0121] Accurately weigh compound 2-1 (944 mg, 2 mmol), compound 4-1 (2520 mg, 6 mmol), and toluene (20 mL) were added to a 50 mL three-necked flask in sequence, the nitrogen atmosphere was replaced three times, tetrakistriphenylphosphine palladium (116 mg, 0.1 mmol) was added, the nitrogen atmosphere was replaced twice, and the mixture was heated to 90 ° C for 3 h. The reaction was monitored by TLC. After the reaction was completed, water was added to quench the reaction, and the mixture was extracted with ethyl acetate. The organic phase was dried over anhydrous sodium sulfate, and the excess solvent was distilled off under reduced pressure. The sample was mixed with silica gel for column chromatography, and the eluent was PE:DCM = 5:1 (v / v) to obtain about 793 mg of compound 4-2, a yield of 69.2%, and MS: 572.80.

[0122] Synthesis of monomer M4:

[0123] Accurately weigh compound 4-2 (573 mg, 1 mmol) and DMF (10 mL) were added to a 50 mL three-necked flask in sequence, and NBS (534 mg, 3 mmol) was added in batches. The temperature was then raised to 80°C and reacted overnight. After the reaction was complete, water was added to quench the reaction, and the mixture was extracted with ethyl acetate. The organic phase was dried over anhydrous sodium sulfate, and the excess solvent was removed by distillation under reduced pressure. The mixture was recrystallized from ethanol to obtain approximately 523 mg of monomer M4 with a yield of 71.6% and MS: 730.45.

[0124] Synthesis of monomer M5:

[0125]

[0126] Synthesis of compound 5-2:

[0127] Accurately weigh compound 2-1 (944 mg, 2 mmol), compound 5-1 (2448 mg, 6 mmol), and toluene (20 mL) were added to a 50 mL three-necked flask in sequence, the nitrogen atmosphere was replaced three times, tetrakistriphenylphosphine palladium (116 mg, 0.1 mmol) was added, the nitrogen atmosphere was replaced twice, and the mixture was heated to 90 ° C for 3 h. The reaction was monitored by TLC. After the reaction was completed, water was added to quench the reaction, and the mixture was extracted with ethyl acetate. The organic phase was dried over anhydrous sodium sulfate, and the excess solvent was distilled off under reduced pressure. The sample was mixed with silica gel for column chromatography, and the eluent was PE:DCM = 5:1 (v / v) to obtain about 745 mg of compound 5-2, with a yield of 68.1%, and MS: 547.12.

[0128] Synthesis of monomer M5:

[0129] Accurately weigh compound 5-2 (548 mg, 1 mmol) and DMF (10 mL) were added sequentially into a 50 mL three-necked flask, and NBS (534 mg, 3 mmol) was added in batches. The temperature was then raised to 80°C and reacted overnight. After the reaction was complete, water was added to quench the reaction, and the mixture was extracted with ethyl acetate. The organic phase was dried over anhydrous sodium sulfate, and the excess solvent was removed by distillation under reduced pressure. The mixture was recrystallized from ethanol to obtain approximately 528 mg of monomer M5 with a yield of 74.9% and MS: 704.69.

[0130] Synthesis of monomer M6:

[0131]

[0132] Accurately weigh compound 6-1 (870 mg, 2 mmol) and THF (20 mL) were added to a 50 mL three-necked flask in sequence, and the nitrogen was replaced three times. n-BuLi (2.4 mL, 6 mmol, 2.5 M) was added dropwise at -75 ° C. and stirred for 1 h. Trimethyltin chloride (1275 mg, 6.4 mmol) was added dropwise at -75 ° C. Then the mixture was naturally restored to room temperature and stirred for 5 h. After the reaction was completed, water was added to quench the reaction, and the mixture was extracted with petroleum ether. The organic phase was dried over anhydrous sodium sulfate, and the excess solvent was distilled off under reduced pressure. The mixture was recrystallized from isopropanol to obtain about 1014 mg of monomer M6 with a yield of 66.7% and MS: 760.51.

[0133] Synthesis of monomer M7:

[0134]

[0135] Accurately weigh compound 7-1 (982 mg, 2 mmol) and THF (20 mL) were added to a 50 mL three-necked flask in sequence, and the nitrogen was replaced three times. n-BuLi (2.4 mL, 6 mmol, 2.5 M) was added dropwise at -75 ° C. and stirred for 1 h. Trimethyltin chloride (1275 mg, 6.4 mmol) was added dropwise at -75 ° C. Then the mixture was naturally returned to room temperature and stirred for 5 h. After the reaction was completed, water was added to quench the reaction, and petroleum ether was extracted. The organic phase was dried over anhydrous sodium sulfate, and the excess solvent was distilled off under reduced pressure. The mixture was recrystallized from isopropanol to obtain about 1225 mg of monomer M7 with a yield of 75.0% and MS: 816.77.

[0136] Synthesis of monomer M8:

[0137]

[0138] Accurately weigh compound 8-1 (837 mg, 2 mmol) and THF (20 mL) were added to a 50 mL three-necked flask in sequence, and the nitrogen was replaced three times. n-BuLi (2.4 mL, 6 mmol, 2.5 M) was added dropwise at -75 ° C. and stirred for 1 h. Trimethyltin chloride (1275 mg, 6.4 mmol) was added dropwise at -75 ° C. Then the mixture was naturally returned to room temperature and stirred for 5 h. After the reaction was completed, water was added to quench the reaction, and the mixture was extracted with petroleum ether. The organic phase was dried over anhydrous sodium sulfate, and the excess solvent was distilled off under reduced pressure. The mixture was recrystallized from isopropanol to obtain about 1203 mg of monomer M8 with a yield of 80.8% and MS: 744.15.

[0139] Synthesis of monomer M9:

[0140]

[0141] Accurately weigh compound 9-1 (950 mg, 2 mmol) and THF (20 mL) were added to a 50 mL three-necked flask in sequence, and the nitrogen was replaced three times. n-BuLi (2.4 mL, 6 mmol, 2.5 M) was added dropwise at -75 ° C. and stirred for 1 h. Trimethyltin chloride (1275 mg, 6.4 mmol) was added dropwise at -75 ° C. Then the mixture was naturally returned to room temperature and stirred for 5 h. After the reaction was completed, water was added to quench the reaction, and the mixture was extracted with petroleum ether. The organic phase was dried over anhydrous sodium sulfate, and the excess solvent was distilled off under reduced pressure. The mixture was recrystallized from isopropanol to obtain about 1158 mg of monomer M9 with a yield of 72.3% and MS: 800.54.

[0142] Synthesis of monomer M10:

[0143]

[0144] Synthesis of compound 10-1:

[0145] Accurately weigh compound 2-1 (4.72 g, 10 mmol), compound 1-2 (11.20 g, 30 mmol), and toluene (100 mL) were added to a 250 mL three-necked flask in sequence, the nitrogen atmosphere was replaced three times, tetrakistriphenylphosphine palladium (580 mg, 0.5 mmol) was added, the nitrogen atmosphere was replaced twice, and the mixture was heated to 90 ° C for 3 h. The reaction was monitored by TLC. After the reaction was completed, water was added to quench the reaction, and the mixture was extracted with ethyl acetate. The organic phase was dried over anhydrous sodium sulfate, and the excess solvent was distilled off under reduced pressure. The sample was mixed with silica gel for column chromatography, and the eluent was PE:DCM = 5:1 (v / v) to obtain about 3.89 g of compound 10-1, with a yield of 81.3%, MS: 478.51.

[0146] Synthesis of monomer M10:

[0147] Compound 10-1 (3.83 g, 8 mmol) and DMF (80 mL) were accurately weighed and added sequentially into a 250 mL three-necked flask. NBS (4.27 g, 24 mmol) was added in batches, and the temperature was then raised to 80°C for overnight reaction. After the reaction was complete, water was added to quench the reaction, and the mixture was extracted with ethyl acetate. The organic phase was dried over anhydrous sodium sulfate, and the excess solvent was removed by distillation under reduced pressure. The mixture was recrystallized from ethanol to obtain approximately 3.69 g of monomer M10 with a yield of 72.5% and MS: 636.09.

[0148] Polymer Synthesis Example 1: Synthesis of Polymer (P1)

[0149]

[0150] Monomer M6 (380 mg, 0.5 mmol) and monomer M1 (309 mg, 0.5 mmol) were accurately weighed and added sequentially to a 50 mL thick-walled pressure-resistant tube. 14 mL of ultra-dry o-xylene was added and nitrogen was purged for 10 minutes. Tetrakistriphenylphosphine palladium (29 mg, 0.025 mmol) was then added and nitrogen purged for another 10 minutes. The reaction mixture was allowed to react at 110°C for 25 hours before heating was discontinued. The reaction solution was cooled to room temperature and added dropwise to methanol to precipitate a solid. The solid was filtered and the filter cake was thoroughly washed in a Soxhlet extractor with n-hexane, ethyl acetate, and dichloromethane. The remaining solid was dissolved in chloroform and added dropwise to methanol to precipitate a solid. The solid was filtered and vacuum dried to obtain approximately 323 mg of polymer (P1) with a yield of 72.5%, Mn: 30.8 kDa, and PDI: 2.54.

[0151] Polymer Synthesis Example 2: Synthesis of Polymer (P2)

[0152]

[0153] Monomer M6 (380 mg, 0.5 mmol) and monomer M10 (318 mg, 0.5 mmol) were accurately weighed and added sequentially to a 50 mL thick-walled pressure-resistant tube. 14 mL of ultra-dry o-xylene was added and nitrogen was purged for 10 minutes. Tetrakistriphenylphosphine palladium (29 mg, 0.025 mmol) was then added and nitrogen purged for another 10 minutes. The reaction mixture was allowed to react at 110°C for 25 hours before heating was stopped. The reaction solution was cooled to room temperature and added dropwise to methanol to precipitate a solid. The solid was filtered and the filter cake was thoroughly washed in a Soxhlet extractor with n-hexane, ethyl acetate, and dichloromethane. The remaining solid was dissolved in chloroform and added dropwise to methanol to precipitate a solid. The solid was filtered and the filter cake was vacuum dried to obtain approximately 344 mg of polymer (P2) with a yield of 75.7%, Mn: 34.7 kDa, and PDI: 2.34.

[0154] Polymer Synthesis Example 3: Synthesis of Polymer (P10)

[0155]

[0156] Monomer M7 (408 mg, 0.5 mmol) and monomer M10 (318 mg, 0.5 mmol) were accurately weighed and added sequentially to a 50 mL thick-walled pressure-resistant tube. 14 mL of ultra-dry o-xylene was added and nitrogen was purged for 10 minutes. Tetrakistriphenylphosphine palladium (29 mg, 0.025 mmol) was then added and nitrogen purged for another 10 minutes. The reaction mixture was allowed to react at 110°C for 25 hours before heating was stopped. The reaction solution was cooled to room temperature and added dropwise to methanol to precipitate a solid. The solid was filtered and the filter cake was thoroughly washed in a Soxhlet extractor with n-hexane, ethyl acetate, and dichloromethane. The remaining solid was dissolved in chloroform and added dropwise to methanol to precipitate a solid. The solid was filtered and the filter cake was vacuum dried to obtain approximately 301 mg of polymer (P10) with a yield of 62.4%, Mn: 28.1 kDa, and PDI: 2.12.

[0157] Polymer Synthesis Example 4: Synthesis of Polymer (P14)

[0158]

[0159] Monomer M7 (408 mg, 0.5 mmol) and monomer M2 (402 mg, 0.5 mmol) were accurately weighed and added sequentially to a 50 mL thick-walled pressure-resistant tube. 14 mL of ultra-dry o-xylene was added and nitrogen was purged for 10 minutes. Tetrakistriphenylphosphine palladium (29 mg, 0.025 mmol) was then added and nitrogen purged for another 10 minutes. The reaction mixture was allowed to react at 110°C for 25 hours before heating was discontinued. The reaction solution was cooled to room temperature and added dropwise to methanol to precipitate a solid. The solid was filtered and the filter cake was thoroughly washed in a Soxhlet extractor with n-hexane, ethyl acetate, and dichloromethane. The remaining solid was dissolved in chloroform and added dropwise to methanol to precipitate a solid. The solid was filtered and vacuum dried to obtain approximately 387 mg of polymer (P14) with a yield of 68.3%, Mn: 33.5 kDa, and PDI: 2.60.

[0160] Polymer Synthesis Example 5: Synthesis of Polymer (P17)

[0161]

[0162] Monomer M8 (372 mg, 0.5 mmol) and monomer M10 (318 mg, 0.5 mmol) were accurately weighed and added sequentially to a 50 mL thick-walled pressure-resistant tube. 14 mL of ultra-dry o-xylene was added and nitrogen was purged for 10 minutes. Tetrakistriphenylphosphine palladium (29 mg, 0.025 mmol) was then added and nitrogen purged for another 10 minutes. The reaction mixture was allowed to react at 110°C for 25 hours before heating was discontinued. The reaction solution was cooled to room temperature and added dropwise to methanol to precipitate a solid. The solid was filtered and the filter cake was thoroughly washed in a Soxhlet extractor with n-hexane, ethyl acetate, and dichloromethane. The remaining solid was dissolved in chloroform and added dropwise to methanol to precipitate a solid. The solid was filtered and vacuum dried to yield approximately 319 mg of polymer (P17) with a yield of 71.5%, Mn: 26.4 kDa, and PDI: 2.57.

[0163] Polymer Synthesis Example 6: Synthesis of Polymer (P23)

[0164]

[0165] Monomer M8 (372 mg, 0.5 mmol) and monomer M3 (336 mg, 0.5 mmol) were accurately weighed and added sequentially to a 50 mL thick-walled pressure-resistant tube. 14 mL of ultra-dry o-xylene was added and nitrogen was purged for 10 minutes. Tetrakistriphenylphosphine palladium (29 mg, 0.025 mmol) was then added and nitrogen purged for another 10 minutes. The reaction mixture was allowed to react at 110°C for 25 hours before heating was stopped. The reaction solution was cooled to room temperature and added dropwise to methanol to precipitate a solid. The solid was filtered and the filter cake was thoroughly washed in a Soxhlet extractor with n-hexane, ethyl acetate, and dichloromethane. The remaining solid was dissolved in chloroform and added dropwise to methanol to precipitate a solid. The solid was filtered and vacuum dried to obtain approximately 285 mg of polymer (P23) with a yield of 61.4%, Mn: 35.2 kDa, and PDI: 2.46.

[0166] Polymer Synthesis Example 7: Synthesis of Polymer (P29)

[0167]

[0168] Monomer M8 (372 mg, 0.5 mmol) and monomer M4 (365 mg, 0.5 mmol) were accurately weighed and added sequentially to a 50 mL thick-walled pressure-resistant tube. 14 mL of ultra-dry o-xylene was added and nitrogen was purged for 10 minutes. Tetrakistriphenylphosphine palladium (29 mg, 0.025 mmol) was then added and nitrogen purged for another 10 minutes. The reaction mixture was allowed to react at 110°C for 25 hours before heating was discontinued. The reaction solution was cooled to room temperature and added dropwise to methanol to precipitate a solid. The solid was filtered and the filter cake was thoroughly washed in a Soxhlet extractor with n-hexane, ethyl acetate, and dichloromethane. The remaining solid was dissolved in chloroform and added dropwise to methanol to precipitate a solid. The solid was filtered and vacuum dried to yield approximately 322 mg of polymer (P29) with a yield of 65.3%, Mn: 36.1 kDa, and PDI: 2.83.

[0169] Polymer Synthesis Example 8: Synthesis of Polymer (P31)

[0170]

[0171] Accurately weigh monomer M9 (400 mg, 0.5 mmol) and monomer M10 (318 mg, 0.5 mmol) and add them to a 50 mL thick-walled pressure-resistant tube in sequence. Add 14 mL of ultra-dry o-xylene and blow nitrogen for 10 minutes. Then add tetrakistriphenylphosphine palladium (29 mg, 0.025 mmol) and continue blowing nitrogen for 10 minutes. After reacting at 110 ° C for 25 hours, stop heating. The reaction solution was cooled to room temperature and added dropwise to methanol to precipitate solids. The solids were filtered and the filter cake was washed thoroughly with n-hexane, ethyl acetate and dichloromethane in a Soxhlet extractor. The remaining solids were dissolved in chloroform and added dropwise to methanol to precipitate solids. The solids were filtered and the filter cake was vacuum dried to obtain about 349 mg of polymer (P31) with a yield of 73.6%, Mn: 35.5 KDa, PDI: 2.36. GPC spectrum is shown in Figure 1 .

[0172] Polymer Synthesis Example 9: Synthesis of Polymer (P36)

[0173]

[0174] Monomer M9 (400 mg, 0.5 mmol) and monomer M5 (353 mg, 0.5 mmol) were accurately weighed and added sequentially to a 50 mL thick-walled pressure-resistant tube. 14 mL of ultra-dry o-xylene was added and nitrogen was purged for 10 minutes. Tetrakistriphenylphosphine palladium (29 mg, 0.025 mmol) was then added and nitrogen purged for another 10 minutes. The reaction mixture was allowed to react at 110°C for 25 hours before heating was discontinued. The reaction solution was cooled to room temperature and added dropwise to methanol. The solid precipitated and was filtered. The filter cake was thoroughly washed with n-hexane, ethyl acetate, and dichloromethane in a Soxhlet extractor. The remaining solid was dissolved in chloroform and added dropwise to methanol to precipitate the solid. The solid was filtered and vacuum dried to obtain approximately 296 mg of polymer (P36) with a yield of 58.1%, Mn: 30.6 kDa, and PDI: 2.73.

[0175] Semi-transparent organic photovoltaic (OPV) device embodiment

[0176] The preparation process and device characterization of the semi-transparent organic photovoltaic cell including the above-mentioned thieno[3,4-b]thiophene-containing polymer are described in detail below through specific device examples.

[0177] refer to Figure 2 The semi-transparent organic photovoltaic cell includes a substrate, an anode, an anode buffer layer, a photoactive layer, a cathode buffer layer and a cathode layer stacked in sequence; wherein the materials of the anode, the anode buffer layer, the photoactive layer, the cathode buffer layer and the cathode layer are, in sequence: indium tin oxide ITO / PEDOT:PSS / photoactive layer material / PNDIT-F3N / ultra-thin metal layer.

[0178] The steps for preparing device embodiment 1 are as follows:

[0179] 1) ITO substrate cleaning:

[0180] The ITO conductive glass was cleaned with detergent, rinsed, and then ultrasonically cleaned with deionized water, acetone, and isopropyl alcohol for 15 minutes. It was then blown dry with nitrogen and treated in a plasma cleaner for 5 minutes to further clean the surface and improve wettability.

[0181] 2) Preparation of anode buffer layer

[0182] PEDOT:PSS(Clevios TM P VP Al 4083) was evenly spin-coated on ITO at a spin-coating speed of 3000 rpm for 30 s, and dried at 150° C. for 15 min to obtain an anode buffer layer.

[0183] 3) Preparation of photoactive layer

[0184] In a glove box (inert gas atmosphere), the photoactive layer material solution is evenly spin-coated on the anode buffer layer at a rotation speed of 1800-4000 rpm to obtain an active material layer with a total thickness of about 100 nm; wherein the donor material in the photoactive layer material solution is selected from polymer (P1); the acceptor material is selected from Y6-BO and PC 61 BM; polymer (P1): Y6-BO: PC 61 BM was added to the chloroform solution at a mass ratio of 1:1.2:0.3, with a total concentration of 15 mg / mL.

[0185] 4) Preparation of cathode buffer layer

[0186] The cathode buffer layer material PNDIT-F3N solution (PNDIT-F3N was dissolved in methanol to prepare a solution with a concentration of 1 mg / mL, and 0.3 vol% acetic acid was added as a cosolvent) was evenly spin-coated on the photoactive layer at a spin coating speed of 2000 rpm and a rotation time of 25 s to obtain a cathode buffer layer.

[0187] 5) Cathode layer preparation

[0188] In high vacuum (1×10 -6 In the atmosphere of 100 mbar, metal Au was first evaporated on the cathode buffer layer to form an Au layer with a thickness of about 1 nm, and then 15 nm of Ag was evaporated on the Au layer to form an Au (1 nm) / Ag (15 nm) cathode layer.

[0189] 6) Packaging

[0190] The devices were encapsulated with UV-curable resin in a nitrogen glove box.

[0191] Device Examples 2-9

[0192] The preparation methods of device examples 2-9 are the same as those of device example 1, except that the donor material in the photoactive layer is selected differently. Specifically, the donor material polymer (P1) is replaced by polymer (P2), polymer (P10), polymer (P14), polymer (P17), polymer (P23), polymer (P29), polymer (P31) and polymer (P36), respectively. See Table 1 for details.

[0193] The prepared semi-transparent organic photovoltaic cell was subjected to a performance test. Under the irradiation of AM1.5 standard light from a solar simulator, the test device data are shown in Table 1.

[0194] Table 1

[0195]

[0196] As shown in Table 1, when the thieno[3,4-b]thiophene-containing polymers described herein are used as donor materials in conjunction with suitable acceptor materials in semi-transparent organic photovoltaic devices, they exhibit excellent photoelectric conversion efficiency and average transmittance. In particular, devices 3, 4, 6, 8, and 9 exhibit photoelectric conversion efficiencies exceeding 11%.

[0197] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A polymer containing thieno[3,4-b]thiophene, characterized in that: It has the structure shown in formula (I): in: Each occurrence of Y is independently selected from O, S or Se; Each occurrence of Z is independently selected from O or S; Each occurrence of R1 is independently selected from -H, -D, -F, -Cl, -Br, -I, -CN or -CF3; R2, at each occurrence, is independently selected from a straight chain alkyl group having 1 to 20 carbon atoms, or a branched chain alkyl group having 3 to 20 carbon atoms; R3, R4, R5, R6, each occurrence, is independently selected from -H, -D, -F, -Cl, -Br, -I, -CN, -CF3, a straight-chain alkyl group having 1-20 carbon atoms, a branched-chain alkyl group having 3-20 carbon atoms, a straight-chain alkoxy group having 1-20 carbon atoms, a branched-chain alkoxy group having 3-20 carbon atoms, a straight-chain alkylthio group having 1-20 carbon atoms, or a branched-chain alkylthio group having 3-20 carbon atoms; Each occurrence of R7 is independently selected from a straight chain alkyl group having 1 to 20 carbon atoms, a branched chain alkyl group having 3 to 20 carbon atoms, a * A substituted or unsubstituted aromatic group having 6 to 20 carbon atoms, or a * a substituted or unsubstituted heteroaromatic group having 5 to 20 ring atoms; R * Each occurrence is independently selected from -D, -F, -Cl, -Br, -I, -CN, -CF3, a straight-chain alkyl group having 1-20 carbon atoms, a branched-chain alkyl group having 3-20 carbon atoms, a straight-chain alkoxy group having 1-20 carbon atoms, a branched-chain alkoxy group having 3-20 carbon atoms, a straight-chain alkylthio group having 1-20 carbon atoms, or a branched-chain alkylthio group having 3-20 carbon atoms; R8, at each occurrence, is independently selected from -H, -D, -F, -Cl, -Br, -I, -CN, -CF3, a straight-chain alkyl group having 1-20 carbon atoms, a branched-chain alkyl group having 3-20 carbon atoms, a straight-chain alkoxy group having 1-20 carbon atoms, a branched-chain alkoxy group having 3-20 carbon atoms, a straight-chain alkylthio group having 1-20 carbon atoms, or a branched-chain alkylthio group having 3-20 carbon atoms; n is the number of repeating units, and n is an integer selected from 1 to 10,000.

2. The polymer containing thieno[3,4-b]thiophenes according to claim 1, characterized in that Having the structure shown in formula (II-1) or (II-2):

3. The polymer containing thieno[3,4-b]thiophenes according to claim 1 or 2, characterized in that Each occurrence of R1 is independently selected from -H, -F or -Cl.

4. The polymer containing thieno[3,4-b]thiophenes according to claim 1 or 2, characterized in that Each occurrence of R2 is independently selected from a straight chain alkyl group having 1 to 10 carbon atoms, or a branched chain alkyl group having 3 to 10 carbon atoms; Preferably, each occurrence of R2 is independently selected from methyl, ethyl, -C6H 13 、-C8H 17 、-C4H9、 or 5. The polymer containing thieno[3,4-b]thiophenes according to claim 1 or 2, characterized in that described Selected from the following groups: Wherein: * indicates the connection site.

6. The polymer containing thieno[3,4-b]thiophenes according to claim 1 or 2, characterized in that Each occurrence of R7 is independently selected from a linear alkyl group having 1 to 20 carbon atoms, a branched alkyl group having 3 to 20 carbon atoms, a * Substituted or unsubstituted phenyl, or R * a substituted or unsubstituted thienyl group; Among them, the R * Each occurrence is independently selected from -D, -F, -Cl, -Br, -I, -CN, -CF3, a straight-chain alkyl group having 1 to 10 carbon atoms, a branched-chain alkyl group having 3 to 10 carbon atoms, a straight-chain alkoxy group having 1 to 10 carbon atoms, a branched-chain alkoxy group having 3 to 10 carbon atoms, a straight-chain alkylthio group having 1 to 10 carbon atoms, or a branched-chain alkylthio group having 3 to 10 carbon atoms.

7. The polymer containing thieno[3,4-b]thiophenes according to claim 2, characterized in that Each occurrence of R8 is independently selected from -H, or -F; Preferably, Selected from the following groups: Preferably, Selected from the following groups:

8. The polymer containing thieno[3,4-b]thiophenes according to claim 1 or 2, characterized in that Each occurrence of R3, R4, R5, and R6 is independently selected from -H, -D, -F, -Cl, -Br, -I, -CN, -CF3, a straight-chain alkyl group having 1 to 10 carbon atoms, a branched-chain alkyl group having 3 to 10 carbon atoms, a straight-chain alkoxy group having 1 to 10 carbon atoms, a branched-chain alkoxy group having 3 to 10 carbon atoms, a straight-chain alkylthio group having 1 to 10 carbon atoms, or a branched-chain alkylthio group having 3 to 10 carbon atoms.

9. The polymer containing thieno[3,4-b]thiophenes according to claim 1, characterized in that The polymer containing thieno[3,4-b]thiophene is selected from the following structures:

10. A mixture, characterized in that The mixture comprises the polymer containing thieno[3,4-b]thiophenes according to any one of claims 1 to 9.

11. An organic photovoltaic cell, characterized in that: The organic photovoltaic cell comprises an anode, a cathode, and a photoactive layer located between the anode and the cathode; the photoactive layer comprises the polymer containing thieno[3,4-b]thiophene according to any one of claims 1 to 9 or the mixture according to claim 10; preferably, the organic photovoltaic cell is a semi-transparent organic photovoltaic cell.

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