Electron transport type conductive ink containing benzodifuranone substance

Abstract

An electron transport type conductive ink containing a benzodifuranone substance, comprising: a benzodifuranone substance, a specific surfactant, and a solvent, wherein the benzodifuranone substance has the following structural unit: (I). The present invention introduces a specific surfactant capable of interacting with the benzodifuranone substance, and the specific surfactant generally contains a unit capable of forming hydrogen bonds or ionic electrostatic interactions with the benzodifuranone substance, so that in addition to the dispersibility of the surfactant itself, the interactions enable the benzodifuranone substance to remain in a more stably dispersed state after dispersion, and not to easily agglomerate over time.

Description

An electron-transmitting conductive ink containing benzodifurandione substances Technical Field

[0001] The present invention belongs to the field of conductive polymer materials, and in particular relates to an electron-transmitting conductive ink containing a benzodifurandione substance, and uses thereof. Background Art

[0002] Conductive polymers generally refer to polymers with alternating conjugated single and double bonds in their backbone. This structure allows charge carriers to migrate along the chain, endowing the material with both semiconducting and conductive properties, thus pioneering the field of organic electronics. Compared to inorganic semiconductors or metals, conductive polymers generally offer significant advantages in terms of processability, lightweightness, flexibility, and the ability to selectively adjust their properties through chemical modification. Since the discovery of conductive polyacetylene, conductive polymers have experienced rapid development. Currently, a variety of conductive polymers, including polyaniline, polythiophene, polypyrrole, and poly(ethylene-3,4-dioxythiophene) (PEDOT), have emerged and found widespread market application in areas such as antistatic coatings, display screens, and capacitors. However, the conductive polymers currently in industrial use typically have a positive backbone and are primarily used to transport cationic charge carriers, known as p-type conductive polymers. In contrast, n-type conductive polymers, with a negative backbone and used to transport anionic charge carriers, have lagged behind in development. The lack of compatible n-type conductive polymers has severely limited the development of organic integrated circuits, which require a combination of high-performance p-type and n-type materials.

[0003] Another advantage of organic conductive polymers is the ability to cost-effectively fabricate large-area devices from solution. However, due to their charge and the strong electrostatic interactions between materials, organic conductive polymers are generally difficult to dissolve. For example, conductive polyacetylene, while its conductivity rivals that of some metals, is insoluble and infusible, making it difficult to process and achieve practical application. Currently, p-type conductive polymers are typically dispersed using polyanionic surfactants, which bind to the positively charged backbone. For example, the combination of polystyrene sulfonic acid (PSS) and PEDOT, PEDOT:PSS, can form a dispersion in water and is particularly important in industry. However, for n-type conductive polymers, alkyl chain modification of the polymer backbone is currently the most common method. This increases the number of steps and cost associated with polymer preparation, making it unsuitable for industrial production. Furthermore, all reported n-type conductive polymers are processed using toxic / carcinogenic organic solvents such as chloroform and chlorobenzene, which poses risks to worker health and the environment when used on a large scale. Recently, a paper (A solution-processed n-type conducting polymer with ultrahigh conductivity. Nature, 2022, 611, 271.) and a patent (An n-type conjugated polymer, its preparation method, and application. Application number: 202110679959.2) disclosed an n-type conducting polymer, poly(benzofurandione) (PBFDO), and its preparation method. A paper (Highly Conductive, and Solution-Processable N-Doped Transparent Organic Conductor. J. Am. Chem. Soc. 2023, 145, 3706) used poly(benzofurandione) to prepare electrodes for electrochromic devices. However, this n-type conducting polymer is currently primarily processed using high-boiling-point solvents such as dimethyl sulfoxide (DMSO), N,N-dimethylacetamide (DMAc), or N,N-dimethylformamide (DMF). On the one hand, film formation requires vacuum removal of the solvent, making the processing steps somewhat cumbersome. On the other hand, it may dissolve the underlying materials during the processing of organic electronic devices, causing damage, requiring the adjustment of the material's solution processing properties. Currently, no n-type conducting polymers that can be processed in water or alcohol solutions have been reported. Summary of the Invention

[0004] Therefore, the purpose of the present invention is to prepare a liquid composition of electron-transporting conductive polymer particles with negative main chain charge and a stable uniform dispersion formed by a water / alcohol solution, thereby filling the gap in the existing water / alcohol-soluble n-type conductive polymers.

[0005] In particular, the present invention also provides a method for adjusting the properties (Seebeck coefficient and work function) of a liquid composition comprising the n-type conductive polymer poly(benzofurandione) (PBFDO) (i.e., a blend of a benzofurandione-based substance and other surfactants), as well as its application in organic electronic devices. The composition can be used to prepare high-performance organic thermoelectric materials and electron transport layers in organic solar cell devices. Compared with the existing technology, the device performance is significantly improved and is more conducive to the preparation of large-area devices.

[0006] The present invention discloses an electron transmission conductive ink containing a benzodifurandione substance, which comprises: a benzodifurandione substance, a specific surfactant and a solvent;

[0007] Wherein, the benzodifurandione substance has the following structural units:

[0008]

[0009] Wherein, m, n, k are positive integers;

[0010] The Y is the counter ion in the n-type conjugated polymer or the n-type conjugated polymer structure containing the counter ion, and the counter ion is selected from one of an organic cation or an inorganic cation;

[0011] The specific surfactant is selected from anionic surfactants, cationic surfactants, nonionic surfactants or amphoteric surfactants;

[0012] The solvent is selected from one or more of water and alcohol solvents.

[0013] Preferably, the solvent is selected from one or more of methanol, ethanol, isopropanol, n-butanol, ethylene glycol monomethyl ether, and ethylene glycol. Preferably, the alcohol solvent is one or more of ethanol, isopropanol, and ethylene glycol monomethyl ether.

[0014] Furthermore, an electron-transmitting conductive ink containing benzodifurandione substances includes the following substances in mass fractions:

[0015] Benzodifurandione substances 0.2~1 wt%

[0016] Specific surfactant 1~6 wt%

[0017] Solvent residue.

[0018] Furthermore, the specific surfactant is selected from surfactants that can form hydrogen bonds with the benzodifurandione substance.

[0019] Furthermore, the specific surfactant is a polymer.

[0020] Furthermore, the structure of the specific surfactant contains one or more of an ether group, an amide group, an ester group or a carbonyl group.

[0021] The present invention introduces a specific surfactant that can interact with the above-mentioned benzodifurandione substances. Generally, the surfactant has a unit that can form hydrogen bonds or ionic electrostatic forces with the benzodifurandione substances. Therefore, in addition to the dispersibility of the surfactant itself, the above-mentioned forces can also make the position of the benzodifurandione substances more stable after dispersion, and are less likely to agglomerate over time, resulting in unsatisfactory dispersion in the dispersion liquid.

[0022] Specifically, the present invention introduces a specific surfactant containing ether or ester groups during the polymerization process of the n-type conductive polymer PBFDO. The surfactant can form hydrogen bonds or ionic electrostatic interactions with PBFDO, thereby forming a composite particle. The solvent is then replaced during dialysis to form a stable water- and alcohol-soluble n-type conductive ink.

[0023] Furthermore, the specific surfactant is selected from one or more of polyether derivatives, polylactic acid derivatives, polyacrylic acid derivatives, polyacrylamide derivatives, polyamide derivatives, imidazole-based polymer derivatives, thiazole-based polymer derivatives, oxazole-based polymer derivatives, and any binary or multi-polymers and their derivatives of any of the above optional objects.

[0024] In the present invention, whether the dispersibility of the electron-transmitting conductive ink containing benzodifurandione substances is ideal is related to the strength of the interaction force formed between the surfactant and the benzodifurandione substances, that is, it is related to the density of the units of hydrogen bonds or ionic electrostatic forces. Therefore, the specific surfactant of the present invention preferably has a polymer structure with a large number of repeating units, so that it can form a strong interaction with the benzodifurandione polymer; small molecule surfactants do not have the above effect, or the effect is very weak.

[0025] The above-mentioned specific surfactants include, but are not limited to, polylactic acid, polylactic acid-glycolic acid copolymer PLGA, poly (N-isopropylacrylamide), poly (N, N-diethylacrylamide), poly (N-vinylcaprolactam), poly (2-ethyl-oxazoline), etc.

[0026] Furthermore, the electron-transmitting conductive ink containing benzodifurandione substances is composed of a solid and a liquid composition;

[0027] The solid accounts for 0.1-20 wt % of the electron-transmitting conductive ink containing benzodifurandione substances.

[0028] Preferably, the solid accounts for 1-10 wt % of the electron-transporting conductive ink containing benzodifurandione substances; more preferably, 1.5-3 wt %.

[0029] Furthermore, the mass ratio of the benzodifurandione substance to the specific surfactant is 1:1-1:10.

[0030] Furthermore, the particle size of the solid is 20-2000 nm. Preferably, the particle size is controlled to be 40-200 nm.

[0031] The particle size of the n-type conductive polymer ions in the liquid composition can be adjusted by changing the addition ratio of the specific surfactant (ie, changing the mass ratio of the conductive polymer to the specific surfactant in the composite particles).

[0032] Furthermore, the liquid composition further comprises one or more of a UV stabilizer, a cross-linking agent, a work function modifier, a preservative, a thickener, and a cosolvent;

[0033] The co-solvent can be selected from one or more of nitrile solvents, ether solvents, ester solvents, sulfoxide solvents, ketone solvents, and amide solvents.

[0034] The UV stabilizer is selected from one or a combination of at least two of 2,2,6,6-tetramethyl-4-piperidinyl ester, phenyl o-hydroxybenzoate, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-hydroxy-4-methoxybenzophenone, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, and hexamethylphosphoric triamide; the crosslinker is selected from one or a combination of at least two of tetraethyl orthosilicate, methacryloxypropyl di-terminated polydimethylsiloxane, and methacryloxypropyl mono-terminated polydimethylsiloxane; and the amphoteric salt work function modifier is selected from one or a combination of at least two of phosphorylcholine, sulfobetaine, carboxybetaine, ammonium oxide, amino acids, and their derivatives.

[0035] Furthermore, the number average molecular weight of the specific surfactant is 10-500 kDa.

[0036] Another object of the present invention is to provide a method for preparing the above-mentioned electron-transmitting conductive ink containing benzodifurandione substances, characterized in that after the preparation of the benzodifurandione substances is completed, the solvent is used to replace the original polar solvent.

[0037] Another object of the present invention is to provide an application of the electron-transmitting conductive ink containing the benzodifurandione substance in the optoelectronic field.

[0038] Based on the various n-type conductive inks prepared, the present invention demonstrates their application as active layers in organic thermoelectric devices and electron transport layers in organic solar cells by fabricating organic electronic devices using them. These methods demonstrate the broad application value of the resulting electron-transport n-type conductive inks in the field of organic electronics.

[0039] Compared with the prior art, the main advantages of the present invention are as follows:

[0040] 1) The conductive ink of the present invention is mainly used for transmitting electrons and has air-stable n-type conductivity, which can meet the requirements of existing organic electronic devices for electron transmission and the development of pn integrated circuits;

[0041] 2) The conductive ink of the present invention can be processed using water / alcohol solvents, overcoming the shortcomings of most existing n-type conductive polymers that use toxic organic solvents. The processing conditions are simple and can meet the requirements of environmentally friendly "green chemistry". BRIEF DESCRIPTION OF THE DRAWINGS

[0042] FIG1 is a graph showing the particle size distribution of the water-dispersible electron-transmitting conductive ink prepared in Example 1;

[0043] FIG2 is a graph showing the particle size distribution of the ethanol-dispersed electron-transmitting conductive ink prepared in Example 2;

[0044] FIG3 is a graph showing the particle size distribution of the isopropyl alcohol-dispersed electron-transmitting conductive ink prepared in Example 4;

[0045] FIG4 is a graph showing the particle size distribution of the isopropyl alcohol-dispersed electron-transmitting conductive ink prepared in Example 5;

[0046] FIG5 is a diagram showing the work function range adjustment of the isopropyl alcohol-dispersed electron transport conductive ink by regulating the addition amount of dodecyldimethylsulfonyl betaine in Example 6;

[0047] FIG6 is a schematic structural diagram of an organic solar cell device prepared in Example 10;

[0048] FIG7 is a performance graph of an organic solar cell device using the electron transport conductive ink prepared according to the present invention as an electron transport layer in Example 10, wherein a blank (i.e., not using the electron transport conductive ink according to the present invention) is provided as a comparative example;

[0049] FIG8 shows the chemical structural formulas of the electron donor material PM6 and the electron acceptor material Y6 of the anode buffer material described in the embodiment. DETAILED DESCRIPTION

[0050] In order to more clearly illustrate the technical solutions of the present invention, the following examples are given. Unless otherwise stated, the raw materials, reactions and post-processing methods mentioned in the examples are common raw materials on the market and technical methods well known to those skilled in the art.

[0051] In the embodiments of the present invention, unless otherwise mentioned, all steps involved in preparing the organic solar cell adopt conventional means well known to those skilled in the art.

[0052] Example 1

[0053] An electron-transmitting conductive ink containing a benzodifurandione substance, comprising the following components in mass fractions:

[0054] Benzodifurandione substances 0.75 wt%

[0055] Polyether F127 5.75 wt%

[0056] Pure water balance.

[0057] The preparation method of the electron-transmitting conductive ink containing benzodifurandione substances is as follows:

[0058]

[0059] Benzo[1,2-b:4,5-b"]difuran-2,6(3H,7H)-dione (380.3 mg, 2 mmol), tetramethyl-1,4-benzoquinone (492.6 mg, 3 mmol), and polyether F127 (Mn = 10,000-30,000 Da) were dissolved in a 1:1 (v / v) mixture of DMSO and DMAc (40 mL total volume). The solution was degassed under vacuum and flushed with nitrogen. After stirring at 80°C for 4 h, the mixture was allowed to cool to room temperature and then added to a pre-treated dialysis bag (molecular weight cutoff 10 kDa). The mixture was first dialyzed against DMSO for three days and then against aqueous solution for solvent exchange. The solution in the dialysis bag was collected and filtered through a polyethersulfone aqueous filter (0.45 μm) to obtain an aqueous solution-processable electron-transporting conductive polymer ink with a solids content of 6.5 wt%.

[0060] Example 2

[0061] An electron-transmitting conductive ink containing a benzodifurandione substance, comprising the following components in mass fractions:

[0062] Benzodifurandione substances 0.65 wt%

[0063] Polyether F127 4.15 wt%

[0064] Ethanol residue.

[0065] The preparation method of the electron-transmitting conductive ink containing benzodifurandione substances is as follows:

[0066]

[0067] Benzo[1,2-b:4,5-b"]difuran-2,6(3H,7H)-dione (380.3 mg, 2 mmol), tetramethyl-1,4-benzoquinone (492.6 mg, 3 mmol), and polyether F127 (Mn = 10,000-30,000 Da) were dissolved in a 1:1 (v / v) mixture of DMSO and DMAc (40 mL total volume). The solution was degassed under vacuum and flushed with nitrogen. After stirring at 80°C for 4 h, the mixture was allowed to cool to room temperature and then added to a pre-treated dialysis bag (molecular weight cutoff 10 kDa). The solution was first dialyzed against DMSO for three days and then against ethanol for solvent exchange. The solution in the dialysis bag was collected and filtered through a polyethersulfone aqueous filter (0.45 um) to obtain an aqueous solution-processable electron-transporting conductive polymer ink with a solids content of 4.8 wt%.

[0068] Example 3

[0069] An electron-transmitting conductive ink containing a benzodifurandione substance, comprising the following components in mass fractions:

[0070] Benzodifurandione substances 0.75 wt%

[0071] Poly(lactic-co-glycolic acid) PLGA 4.65 wt%

[0072] Ethanol / tetrahydrofuran mixed solution (ethanol:tetrahydrofuran = 1:4, v / v) balance.

[0073] The preparation method of the electron-transmitting conductive ink containing benzodifurandione substances is as follows:

[0074]

[0075] Benzo[1,2-b:4,5-b"]difuran-2,6(3H,7H)-dione (380.3 mg, 2 mmol), tetramethyl-1,4-benzoquinone (492.6 mg, 3 mmol), and PLGA were dissolved in DMSO (40 mL total volume). The solution was degassed under vacuum and flushed with nitrogen. After stirring at 80°C for 4 h, the mixture was allowed to cool to room temperature and then added to a pre-treated dialysis bag (molecular weight cutoff 10 kDa). The mixture was first dialyzed against DMSO for three days and then against a mixture of ethanol and tetrahydrofuran (4:1, v / v) for solvent exchange. The solution in the dialysis bag was collected and filtered through a polytetrafluoroethylene filter (0.45 μm). This yielded an ethanol-processable electron-transporting conductive polymer ink (ethanol:tetrahydrofuran = 1:4, v / v) with a solids content of 5.4 wt%.

[0076] Poly(lactic-co-glycolic acid) copolymer (PLGA) (copolymer ratio 1:1, n / n, Mn 40,000-70,000 Da) was purchased from Beijing Huawei Raycus Co., Ltd.

[0077] Example 4

[0078] An electron-transmitting conductive ink containing a benzodifurandione substance, comprising the following components in mass fractions:

[0079] Benzodifurandione substances 0.6 wt%

[0080] Poly(2-ethyl-oxazoline) 2.0 wt%

[0081] Isopropyl alcohol residue.

[0082] The preparation method of the electron-transmitting conductive ink containing benzodifurandione substances is as follows:

[0083]

[0084] Benzo[1,2-b:4,5-b"]difuran-2,6(3H,7H)-dione (380.3 mg, 2 mmol), tetramethyl-1,4-benzoquinone (492.6 mg, 3 mmol), and poly(2-ethyl-oxazoline) were dissolved in a 1:1 (v / v) mixture of DMSO and DMAc (total volume 40 mL). The solution was degassed under vacuum and flushed with nitrogen. After stirring at 80°C for 4 h, the mixture was allowed to cool to room temperature and then added to a pre-treated dialysis bag (molecular weight cutoff 10 kDa). The mixture was first dialyzed against DMSO for three days and then against isopropanol for solvent exchange. The solution in the dialysis bag was collected and filtered through a 1 μm polytetrafluoroethylene filter to obtain an isopropanol-processable electron-transporting conductive polymer ink with a solids content of 2.6 wt%.

[0085] Poly(2-ethyl-oxazoline) (Mn 100,000–250,000 Da) was purchased from MacLean Reagents.

[0086] Example 5

[0087] An electron-transmitting conductive ink containing a benzodifurandione substance, comprising the following components in mass fractions:

[0088] Benzodifurandione substances 0.65 wt%

[0089] Poly(2-ethyl-oxazoline) 4.15 wt%

[0090] Isopropyl alcohol residue.

[0091] The preparation method of the electron-transmitting conductive ink containing benzodifurandione substances is as follows:

[0092]

[0093] Benzo[1,2-b:4,5-b"]difuran-2,6(3H,7H)-dione (380.3 mg, 2 mmol), tetramethyl-1,4-benzoquinone (492.6 mg, 3 mmol), and poly(2-ethyl-oxazoline) were dissolved in a 1:1 (v / v) mixture of DMSO and DMAc (total volume 40 mL). The solution was degassed under vacuum and flushed with nitrogen. After stirring at 80°C for 4 h, the mixture was allowed to cool to room temperature and then added to a pre-treated dialysis bag (molecular weight cutoff 10 kDa). The mixture was first dialyzed against DMSO for three days and then against isopropanol for solvent exchange. The solution in the dialysis bag was collected and filtered through a 0.45 μm organic polytetrafluoroethylene filter to obtain isopropanol-processable electron-transporting conductive polymer inks with varying particle sizes. The resulting solution had a solid content of 4.8 wt%.

[0094] Poly(2-ethyl-oxazoline) (Mn 100,000–250,000 Da) was purchased from MacLean Reagents.

[0095] Example 6

[0096] Based on the conductive ink prepared in Example 5, dodecyldimethylsulfonyl betaine was further added to achieve the preparation of an electron-transmitting conductive ink with a low work function and alcohol-soluble processability. The process is as follows:

[0097] To 50 mL of the conductive ink prepared in Example 5, 720 mg of dodecyldimethylsulfonyl betaine (35 wt% of the total benzodifurandione content) was added. The mixture was stirred at room temperature for 30 minutes, homogenized for 10 minutes, and filtered through a 0.45 μm organic polytetrafluoroethylene filter to obtain an alcohol-soluble, electron-transmitting conductive ink with a low work function. The work function was 4.15 eV as measured by Kelvin probe. Furthermore, the work function can be further adjusted by controlling the amount of dodecyldimethylsulfonyl betaine added (as shown in Figure 5).

[0098] Example 7

[0099] Based on the conductive ink prepared in Example 6, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole was further added to achieve the preparation of an electron-transmitting conductive ink with UV resistance, low work function, and alcohol-soluble processability. The process is as follows:

[0100] To 50 mL of the conductive ink prepared in Example 6, 120 mg of 2-(2'-hydroxy-5'-methylphenyl)benzotriazole (5 wt% of the benzodifurandione substance) was added. The mixture was stirred at room temperature for 30 min, homogenized in a homogenizer for 10 min, and filtered through an organic polytetrafluoroethylene filter (0.45 um) to obtain an alcohol-soluble, processable, and UV-resistant electron-transmitting conductive ink.

[0101] Comparative Example 1

[0102] This comparative example does not add any additional surfactant. The specific process is as follows:

[0103] Benzo[1,2-b:4,5-b"]difuran-2,6(3H,7H)-dione (380.3 mg, 2 mmol) and tetramethyl-1,4-benzoquinone (492.6 mg, 3 mmol) were dissolved in DMSO (40 mL). The solution was degassed under vacuum and flushed with nitrogen. After stirring at 80°C for 6 h, the mixture was allowed to cool to room temperature. The solution was then added to a pre-treated dialysis bag (molecular weight cutoff 10 kDa) and dialyzed against DMSO for three days. Subsequently, the solution was dialyzed against ethanol for solvent exchange. During the dialysis process, as the DMSO was replaced by ethanol, the prepared poly(benzofurandione) precipitated as a solid in the dialysis bag, preventing the production of a conductive polymer ink processable in ethanol.

[0104] Comparative Example 2

[0105] This comparative example uses a low molecular weight F127 surfactant. The specific process is as follows:

[0106] Benzo[1,2-b:4,5-b"]difuran-2,6(3H,7H)-dione (380.3 mg, 2 mmol), tetramethyl-1,4-benzoquinone (492.6 mg, 3 mmol), and polyether F127 (Mn = 5000 Da) were dissolved in a 1:1 (v / v) mixture of DMSO and DMAc (total volume 40 mL). The solution was degassed under vacuum and flushed with nitrogen. After stirring at 80°C for 4 h, the mixture was allowed to cool to room temperature and then added to a pre-treated dialysis bag (molecular weight cutoff 10 kDa). The solution was first dialyzed against DMSO for three days and then against aqueous solution for solvent exchange. The liquid in the dialysis bag was then collected and filtered through a polyethersulfone aqueous filter (0.45 um). However, the prepared solution could not pass through the filter, and thus an aqueous solution-processable electron-transporting conductive polymer ink could not be obtained.

[0107] Comparative Example 3

[0108] This comparative example uses an equal mass of poly(diallyldimethylammonium chloride) as a surfactant instead of the polyether F127 in Example 1. The specific process is as follows:

[0109] Benzo[1,2-b:4,5-b"]difuran-2,6(3H,7H)-dione (380.3 mg, 2 mmol), tetramethyl-1,4-benzoquinone (492.6 mg, 3 mmol), and poly(diallyldimethylammonium chloride) (Mn = 400,000-500,000 Da) were dissolved in a 1:1 (v / v) mixture of DMSO and DMAc (40 mL total volume). The solution was degassed under vacuum and flushed with nitrogen. After stirring at 80°C for 4 h, the mixture was allowed to cool to room temperature and then added to a pre-treated dialysis bag (molecular weight cutoff 10 kDa). The mixture was first dialyzed against DMSO for three days and then dialysis against aqueous solution for solvent exchange. During the solvent exchange process, the resulting mixture gradually precipitated as a solid in the dialysis bag, preventing the production of an aqueous solution-processable electron-transporting conductive polymer ink.

[0110] Test Example 1

[0111] The liquids prepared in Examples 1-5 and Comparative Example 2 were spin-coated into films, and the conductivity of the resulting films was measured using a quadruped probe method to illustrate the high conductivity characteristics of the water-alcohol-soluble electron-transmitting conductive ink proposed in the present invention.

[0112] Testing conditions were as follows: glass substrates were cleaned with deionized water, acetone, and isopropyl alcohol, respectively, and dried in an oven at 60°C. Thin films were then spin-coated at 2000 rpm onto the cleaned glass substrates. Sheet resistivity of the films was measured using a Halpa HPS2663 quad-probe probe, and thickness was measured using a step profiler. The resulting films can be variably adjusted by varying the surfactant and dosage.

[0113] Table 1 Conductivity test of conductive ink in Examples 1-5 and Comparative Example 2

[0114]

[0115] From the above data, it can be seen that the obtained film can be greatly adjusted by varying the surfactant and the amount used.

[0116] Test Example 2

[0117] The electron-transmitting conductive ink prepared in Example 4 was spin-coated into a film. Different temperature differences were applied on both sides of the film to measure the Seebeck coefficient of the obtained material. Combined with the conductivity measured in Example 8, the power factor was calculated to be 195 μW m -1 K-2 , which illustrates the application of the water-alcohol soluble electron-transmitting conductive ink proposed by the present invention in n-type thermoelectric devices.

[0118] Table 2 Thermoelectric performance parameters of the conductive ink in Example 4

[0119]

[0120] Test Example 3

[0121] The low-work-function, alcohol-soluble, electron-transporting conductive ink prepared in Example 6 was used to prepare the electron transport layer of an organic solar cell, demonstrating the application of the conductive ink of the present invention as an electron transport material in organic optoelectronic devices. The organic solar cell device structure is ITO (20 nm) / PEDOT:PSS (40 nm) / PM6:Y6 (1:1.5, m / m, 100 nm) / electron transport layer (10-150 nm) / silver electrode (80 nm). The structure is shown in Figure 6. The device preparation process is as follows:

[0122] A glass substrate coated with indium tin oxide (ITO) was cleaned with deionized water, acetone, and isopropanol, respectively, and dried in an oven at 60°C. A 40 nm thick layer of poly(3,4-ethylenedioxythiophene):polystyrenesulfonic acid (PEDOT:PSS, CLEVIOS PVP Al 4083) was then spin-coated onto the cleaned ITO glass substrate and heated on a hot plate at 140°C in air for 15 min. The active layer donor material, conjugated polymer PM6, and the acceptor material, Y6, were weighed in a clean bottle at a ratio of 1:1.5 (m / m). The mixture was transferred to a nitrogen-protected film-forming glove box (purchased from VAC) and dissolved in chloroform containing 1 wt% 1,8-diiodooctane. A 100 nm thick active layer film was then spin-coated onto the PEDOT:PSS film using a spin spinner and a surface profiler. The low work function, alcohol-soluble, electron-transporting conductive ink obtained in Example 6 was diluted with isopropyl alcohol to different concentrations and spin-coated on the active layer to prepare an electron-transporting layer with a thickness of 10 to 100 nm. The film was then transferred to a vacuum deposition chamber connected to a glove box and then deposited through a mask at approximately 10 -7 Silver (80 nm) electrodes were evaporated under the conditions of Pa.

[0123] The energy of the simulated sunlight was calibrated to 100 mW / cm3 using a silicon photodiode calibrated by the National Renewable Energy Laboratory (NREL) and a KG5 filter before testing. 2The energy conversion efficiency of the device was measured under a standard solar spectrum AM1.5 solar simulator (Model 91192, Oriel, USA), and the photon and unilluminated carrier density-voltage (JV) characteristics of the solar cell device were recorded using a Keithley 2410 and a Keithley 236 digital source meter, respectively.

[0124] This embodiment also provides a comparative example without the conductive ink of the present invention, that is, without an electron transport layer. The relationship between the current density and voltage of the device under illumination is shown in FIG7 , and the specific device efficiency is shown in Table 3.

[0125] FIG8 shows the chemical structural formulas of the electron donor material PM6 and the electron acceptor material Y6 of the anode buffer material described in the embodiment.

[0126] Table 3 Performance of organic solar cells based on electron transport layers of different thicknesses prepared with conductive ink in Example 6

[0127]

[0128] From the above data, it can be seen that the electron transport conductive ink prepared by the present invention can be used as an electron transport layer, significantly improving device performance and having excellent thickness insensitivity.

[0129] Test Example 4

[0130] The alcohol-soluble, electron-transmitting conductive ink prepared in Example 4 was spin-coated into films, which were then thermally annealed at various temperatures in an inert atmosphere for 30 minutes. The conductivity of the films was then measured. This demonstrates that the films formed from the conductive ink of the present invention exhibit excellent thermal stability and can further crystallize upon heating, achieving improved conductivity. The test results are shown in Table 4.

[0131] Table 4 Conductivity of the conductive ink after spin coating and thermal annealing in Example 4

[0132]

[0133] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations that come within the meaning and range of equivalents of the claims be embraced therein.

[0134] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. An electron-transporting conductive ink containing benzodifurandione substances, characterized in that, The electron-transporting conductive ink containing benzodifurandione substances comprises: benzodifurandione substances, a specific surfactant, and a solvent; Among them, the benzodifurandione substances have the following structural units: ； Among them, m, n, and k are positive integers; The Y is a counter ion in the structure and is selected from one of organic cations or inorganic cations; The specific surfactant is selected from anionic surfactants, cationic surfactants, nonionic surfactants, or amphoteric surfactants; The solvent is selected from one or more of water and alcohol solvents.

2. The electron-transporting conductive ink containing benzodifurandione substances according to claim 1, characterized in that The electron-transporting conductive ink containing benzodifurandione substances comprises substances with the following mass fraction components: Benzodifurandione substances 0.2 - 1 wt% Specific surfactant 1 - 6 wt% Solvent balance.

3. The electron transport type conductive ink containing benzodifurandione substances according to claim 1, characterized in that, The specific surfactant is selected from surfactants that can form hydrogen bonds with the benzodifurandione substances.

4. The electron transport type conductive ink containing benzodifurandione substances according to claim 1, characterized in that, The specific surfactant is a polymer and has one or more of an ether group, an amide group, an ester group, or a carbonyl group.

5. The electron-transporting conductive ink containing benzodifurandione substances according to claim 4, characterized in that, The specific surfactant is selected from polyether derivatives, polylactic acid derivatives, polyacrylic acid derivatives, polyacrylamide derivatives, polyamide derivatives, imidazole-based polymer derivatives, thiazole-based polymer derivatives, oxazole-based polymer derivatives, and any binary or multi-polymer and its derivatives among the above optional objects, one or more of them.

6. The electron transport type conductive ink containing benzodifurandione substances according to claim 1, characterized in that, In the electron-transporting conductive ink containing benzodifurandione substances, it consists of a solid and a liquid composition; Among them, the solid accounts for 0.1 - 20 wt% of the electron-transporting conductive ink containing benzodifurandione substances.

7. The electron transport type conductive ink containing benzodifurandione substances according to claim 6, characterized in that, The liquid composition further includes one or more of a UV stabilizer, a crosslinking agent, a work function regulator, a preservative, a thickening agent, and a co-solvent; The co-solvent can be selected from one or more of nitrile solvents, ether solvents, ester solvents, sulfoxide solvents, ketone solvents, and amide solvents.

8. The electron-transporting conductive ink containing benzodifurandione substances according to claim 1, characterized in that, The number average molecular weight of the specific surfactant is 5 kDa - 500 kDa.

9. The preparation method of the electron transport type conductive ink containing benzodifurandione substances according to any one of claims 1-8, characterized in that, After the preparation of the benzodifurandione substance-containing material is completed, the original polar solvent is replaced with the solvent.

10. The application of the electron-transporting conductive ink containing benzodifurandione substances according to any one of claims 1 - 8 in the optoelectronic field.

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