Electron transport conductive ink containing benzodifurandione-based materials

Abstract

The present invention discloses an electron transport conductive ink containing a benzodifuran-based substance, the electron transport conductive ink containing the benzodifuran-based substance comprising a benzodifuran-based substance, a specific surfactant, and a solvent, The benzodifurandione-based substance has the following structural units: [Formula 1] JPEG2026502810000013.jpg127170The present invention provides for the introduction of a specific surfactant capable of interacting with the above-mentioned benzodifurandione-based substance, typically one having a unit that forms a hydrogen bond or an ionic electrostatic force with the benzodifurandione-based substance. In addition to the dispersibility of the surfactant itself, the above-mentioned force stabilizes the position of the benzodifurandione-based substance after dispersion, making it less likely to aggregate over time and result in undesirable dispersibility in the dispersion liquid.

Description

[Technical Field]

[0001] The present invention is in the field of conductive polymer materials, and more particularly relates to electron transport conductive inks containing benzodifurandione-based materials and their uses. [Background technology]

[0002] Conductive polymers typically refer to polymers with alternating conjugated structures of single and double bonds in the main chain. This structure allows carriers to migrate along the main chain, endowing the material with semiconducting and conducting properties, paving the way for organic electronics. Compared to inorganic semiconducting materials and metals, conductive polymers typically offer advantages such as processability, light weight, flexibility, and ease of modification through chemical structure and selectivity control. Since the discovery of conductive polyacetylene, conductive polymers have developed rapidly. Currently, many conductive polymers, including polyaniline, polythiophene, polypyrrole, and poly(3,4-ethylenedioxythiophene) (PEDOT), have emerged and are widely used in antistatic coatings, displays, and capacitors. However, currently commercially available conductive polymers typically have a positively charged main chain and are primarily used to transport cation carriers, i.e., p-type conductive polymers. On the other hand, the development of n-type conductive polymers for transporting anion carriers due to their negatively charged main chains has been slow, and there has been a lack of compatible n-type conductive polymer materials for p-type, which has significantly limited the development of organic integrated circuits that require a combination of high-performance p-type and n-type materials.

[0003] Another advantage of organic conductive polymers is their ability to be fabricated into large-area devices at low cost using solutions. However, because organic conductive polymers are charged, strong electrostatic interactions exist between materials, making them generally difficult to dissolve. For example, conductive polyacetylene has a conductivity comparable to that of some metals, but its insolubility and infusibility make it difficult to process for practical use. Currently, p-type conductive polymers typically employ polyanionic surfactants to bond with the positively charged backbone and achieve dispersion. For example, the conjugate of polystyrene sulfonate (PSS) and PEDOT (PEDOT:PSS) can form dispersions in water, making it particularly important in industrial applications. However, the current method for producing n-type conductive polymers involves modifying the polymer backbone with alkyl chains, which increases the manufacturing process and costs, making industrial production unsuitable. Meanwhile, currently reported n-type conductive polymers are processed using toxic / carcinogenic organic solvents such as chloroform and chlorobenzene, which can harm the health of workers and the environment in large-scale applications. Recently, a paper (A solution-processed n-type conducting polymer with ultrahigh conductivity. Nature, 2022, 611, 271) and a Chinese patent publication (n-type conjugated polymer and its manufacturing method, application number: 202110679959.2) have disclosed the n-type conductive polymer polybenzodifurandione (PBFDO) and its manufacturing method. Another paper (Highly Conductive and Solution-Processable N-doped Transparent Organic Conductor. J. Am. Chem. Soc. 2023, 145, 3706) reported the fabrication of electrodes for electrochromic devices from polybenzodifurandione. However, currently, these n-type conductive polymers are mainly processed in high-boiling solvents such as dimethyl sulfoxide (DMSO), N,N-dimethylacetamide (DMAc), or N,N-dimethylformamide (DMF).The deposition process requires the removal of the solvent in a vacuum, which makes the processing somewhat cumbersome, and the solution processing properties of the material must be adjusted to avoid the possibility of the underlying material being dissolved and destroyed when processing organic electronic devices. Currently, no n-type conductive polymers that can be processed in a water / alcohol solution have been reported. Summary of the Invention [Problem to be solved by the invention]

[0004] Therefore, the object of the present invention is to realize the preparation of a liquid composition of a stable and uniform dispersion of electron-transport conductive polymer particles with negatively charged main chains and a water / alcohol solution, thereby filling the void of n-type conductive polymers that can be processed in conventional water / alcohol solutions.

[0005] In particular, the present invention provides a method for adjusting properties (Seebeck coefficient and work function) based on a liquid composition containing polybenzodifurandione (PBFDO), an n-type conductive polymer (i.e., a benzodifurandione-based material blended with other surfactants), and its use in organic electronic devices. This method can be used to produce high-performance organic thermoelectric materials and electron transport layers in organic solar cell devices, significantly improving device performance compared to conventional techniques and advantageously enabling the production of larger-area devices. [Means for solving the problem]

[0006] The present invention discloses an electron transport conductive ink containing a benzodifuran-based material. The electron transport conductive ink containing a benzodifuran-based material includes a benzodifuran-based material, a specific surfactant, and a solvent, The benzodifurandione-based substance has the following structural units: [ka] where m, n, and k are positive integers, Y is an n-type conjugated polymer containing a counterion or a counterion in the structure of the n-type conjugated polymer, and the counterion is one selected from an organic cation or an inorganic cation; the specific surfactant is selected from an anionic surfactant, a cationic surfactant, a nonionic surfactant, or an amphoteric surfactant; The solvent is one or more selected from water and alcohol-based solvents.

[0007] Preferably, the solvent is one or more selected from methanol, ethanol, isopropyl alcohol, n-butanol, ethylene glycol monomethyl ether, and ethylene glycol. Preferably, the alcohol-based solvent is one or more selected from ethanol, isopropyl alcohol, and ethylene glycol monomethyl ether.

[0008] Further, an electron transport conductive ink containing a benzodifurandione-based material, the electron transport conductive ink containing a benzodifurandione-based material, comprises the following mass fractions of components: Benzodifurandione substances 0.2~1wt% Specific surfactant 1-6wt% Solvent balance.

[0009] Furthermore, the specific surfactant is selected from surfactants that can form hydrogen bonds with the benzodifurandione-based substance.

[0010] Furthermore, the specific surfactant is a polymer.

[0011] Furthermore, the structure of the specific surfactant has one or more of an ether group, an amide group, an ester group, or a carbonyl group.

[0012] The present invention introduces a specific surfactant that can interact with the above-mentioned benzodifurandione-based substance, usually one that has a unit that forms a hydrogen bond or an ionic electrostatic force with the benzodifurandione-based substance.In addition to the dispersibility of the surfactant itself, the above-mentioned force stabilizes the position of the benzodifurandione-based substance after dispersion, making it less likely to aggregate over time and result in undesirable dispersibility in the dispersion liquid.

[0013] Specifically, the present invention introduces a specific surfactant containing an ether bond or an ester group during the polymerization process of PBFDO, an n-type conductive polymer, which forms hydrogen bonds or ionic-electrostatic interactions with PBFDO and combines with it to form particles. Furthermore, through solvent replacement during the dialysis process, a stable n-type conductive ink is formed that can be processed in a water / alcohol solution.

[0014] Furthermore, the specific surfactant is one or more selected from polyether derivatives, polylactic acid derivatives, polyacrylic acid derivatives, polyacrylamide derivatives, polyamide derivatives, imidazole polymer derivatives, thiazole polymer derivatives, oxazole polymer derivatives, and any divalent or polyvalent polymers thereof and their derivatives.

[0015] In the present invention, whether the dispersibility of the electron transport conductive ink containing a benzodifuran-based substance is ideal depends on the strength of the interaction between the surfactant and the benzodifuran-based substance, i.e., the density of units of hydrogen bonding or ionic electrostatic interaction. Therefore, it is preferable that the specific surfactant of the present invention has a polymer structure with many repeating units so that it can form strong interactions with polymer compounds such as benzodifuran-based substances. On the other hand, small molecule surfactants do not have the above effect or have only a small effect.

[0016] The specific surfactants include, but are not limited to, polylactic acid, polylactic acid-hydroxyacetic acid copolymer (PLGA), poly(N-isopropylacrylamide), poly(N,N-diethylacrylamide), poly(N-vinylcaprolactam), poly(2-ethyloxazoline), and the like.

[0017] Furthermore, the electron transport conductive ink containing the benzodifuran-based substance is composed of a solid and liquid composition, and the solid content accounts for 0.1 to 20 wt% of the electron transport conductive ink containing the benzodifuran-based substance.

[0018] Preferably, the solid occupies 1 to 10 wt %, more preferably 1.5 to 3 wt %, of the electron transport conductive ink containing the benzodifurandione-based substance.

[0019] Furthermore, the mass ratio of the benzodifurandione substance to the specific surfactant is 1:1 to 1:10.

[0020] Furthermore, the particle size of the solid is 20 to 2,000 nm, preferably 40 to 200 nm.

[0021] The particle size of the n-type conductive polymer ions contained in the liquid composition is adjusted by changing the addition ratio of the specific surfactant, i.e., by changing the mass ratio of the conductive polymer and the specific surfactant in the composite particles.

[0022] The liquid composition further comprises one or more of a UV stabilizer, a crosslinking agent, a work function modifier, a preservative, a thickener, and a solubilizing agent.

[0023] The solubilizing agent is one or more selected from the group consisting of nitrile solvents, ether solvents, ester solvents, sulfoxide solvents, ketone solvents, and amide solvents.

[0024] Here, the UV stabilizer is one or a combination of at least two selected from 2,2,6,6-tetramethyl-4-piperidinyl esters, phenyl o-hydroxybenzoate, 2-(2'-hydroxy-5'-methylphenyl)-benzotriazole, 2-hydroxy-4-methoxybenzophenone, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, and hexamethylphosphortriamine.

[0025] The crosslinking agent is one or a combination of at least two selected from tetraethyl orthosilicate, polydimethylsiloxane having methacryloxypropyl at both ends, and polydimethylsiloxane having methacryloxypropyl at one end.

[0026] The work function adjuster is one or a combination of at least two selected from phosphocholine, sulfobetaine, carboxybetaine, ammonium oxide, amino acid-based substances, and derivatives thereof.

[0027] Furthermore, the number average molecular weight of the specific surfactant is 10 to 500 kDa.

[0028] Another object of the present invention is to provide a method for producing an electron transport conductive ink containing the above-mentioned benzodifuran-based material, in which the original polar solvent is replaced with the above solvent after the production of the benzodifuran-based material is completed.

[0029] Another object of the present invention is to provide an electron transport conductive ink containing the above benzodifurandione-based material for use in the field of optoelectronics.

[0030] In this invention, organic electronic devices were fabricated based on the prepared n-type conductive inks, and their use as an active layer in organic thermoelectric devices and as an electron transport layer in organic solar cells was demonstrated. These methods demonstrated the wide range of applications of the obtained electron transport n-type conductive inks in the organic electronics field. [Effects of the Invention]

[0031] Compared with the prior art, the main advantages of the present invention are as follows:

[0032] (1) The conductive ink of the present invention is mainly used for electron transport and has air-stable n-type conductivity, which can meet the needs for electron transport in existing organic electronic devices and the development of pn integrated circuits.

[0033] (2) The conductive ink of the present invention can be processed using a water / alcohol solvent, overcoming the drawback of using toxic organic solvents in many conventional n-type conductive polymers, and meeting the demand for "green chemistry" with simple processing conditions and environmental friendliness. [Brief explanation of the drawings]

[0034] [Figure 1] FIG. 2 is a graph showing the particle size distribution of the water-dispersed electron transport conductive ink produced in Example 1. [Figure 2] FIG. 10 is a graph showing the particle size distribution of the ethanol-dispersed electron transport conductive ink produced in Example 2. [Figure 3] FIG. 10 is a graph showing particle size distribution measurement of the isopropyl alcohol-dispersed electron transport conductive ink produced in Example 4. [Figure 4] FIG. 10 is a graph showing the particle size distribution of the isopropyl alcohol-dispersed electron transport conductive ink produced in Example 5. [Figure 5] FIG. 10 is a diagram showing the adjustment of the work function range of the isopropyl alcohol-dispersed electron transport conductive ink achieved by controlling the amount of dodecyldimethylsulfopropylbetaine added in Example 6. [Figure 6] FIG. 1 is a schematic diagram illustrating the configuration of an organic solar cell element produced in Test Example 3. [Figure 7] FIG. 10 is a performance graph of an organic solar cell element using the electron transport type conductive ink of the present invention manufactured in Test Example 3 as an electron transport layer, and shows, as a comparative example, a case where a blank was provided, i.e., no electron transport type conductive ink of the present invention was used. [Figure 8] 1 shows the chemical structural formulas of an electron donor material PM6 and an electron acceptor material Y6 of an anode buffer material according to an example. DETAILED DESCRIPTION OF THE INVENTION

[0035] In order to more clearly explain the technical solution of the present invention, the following examples are given. Unless otherwise specified, the raw materials, reaction and post-treatment means appearing in the examples are common raw materials on the market and technical means well known to those skilled in the art.

[0036] In the embodiments of the present invention, unless otherwise specified, conventional means well known to those skilled in the art are employed in the manufacturing process of the organic solar cell.

[0037] Example 1

[0038] An electron transport conductive ink comprising a benzodifurandione-based material comprising the following mass fractions of components: Benzodifurandione-based substances 0.75wt% Polyether F127 5.75wt% Pure water remainder.

[0039] The method for producing the electron transport conductive ink containing the above-mentioned benzodifurandione-based substance is as follows.

[0040] [ka]

[0041] 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 (total volume 40 mL). The solution was degassed under vacuum and protected with nitrogen gas. After stirring at 80 °C for 4 h, the mixture was cooled to room temperature and placed in a pre-treated permeation bag (10 kDa molecular weight cutoff). The solution was first dialyzed against DMSO for 3 days, followed by aqueous dialysis. The solution in the permeation bag was then collected and filtered through a polyethersulfone aqueous filter head (0.45 μm) to obtain an aqueous processable electron transport conductive polymer ink. The solids content of the resulting solution was 6.5 wt%.

[0042] Example 2

[0043] An electron transport conductive ink comprising a benzodifurandione-based material comprising the following mass fractions of components: Benzodifurandione-based substances 0.65wt% Polyether F127 4.15wt% Ethanol remainder.

[0044] The method for producing the electron transport conductive ink containing the above-mentioned benzodifurandione-based substance is as follows.

[0045] [ka]

[0046] 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 (total volume 40 mL). The solution was degassed under vacuum and protected with nitrogen gas. After stirring at 80 °C for 4 h, the mixture was cooled to room temperature and placed in a pre-treated permeation bag (10 kDa molecular weight cutoff). The solution was dialyzed against DMSO for 3 days, followed by ethanol dialysis. The solution in the permeation bag was then collected and filtered through a polyethersulfone aqueous filter head (0.45 μm) to obtain an aqueous processable electron-transport conductive polymer ink. The solids content of the resulting solution was 4.8 wt%.

[0047] Example 3

[0048] An electron transport conductive ink comprising a benzodifurandione-based material comprising the following mass fractions of components: Benzodifurandione-based substances 0.75wt% Polylactic acid-hydroxyacetic acid copolymer PLGA 4.65wt% The remainder was an ethanol / tetrahydrofuran mixed solution (ethanol:tetrahydrofuran=1:4, v / v).

[0049] The method for producing the electron transport conductive ink containing the above-mentioned benzodifurandione-based substance is as follows.

[0050] [ka]

[0051] 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 protected with nitrogen gas. After stirring at 80 °C for 4 h, the mixture was cooled to room temperature and placed in a pre-treated permeation bag (10 kDa molecular weight cutoff). The solution was dialyzed against DMSO for 3 days, followed by dialysis against an ethanol / tetrahydrofuran mixture (1:4, v / v). The solution was then collected and filtered through a polytetrafluoroethylene filter head (0.45 μm) to obtain an electron-transporting conductive polymer ink processable in ethanol (ethanol:tetrahydrofuran = 1:4, v / v). The solids content of the resulting solution was 5.4 wt%.

[0052] Polylactic acid-hydroxyacetic acid copolymer PLGA (copolymerization ratio 1:1, n / n, Mn 40,000-70,000 Da) was purchased from Beijing Huawei Aerobic Co., Ltd.

[0053] Example 4

[0054] An electron transport conductive ink comprising a benzodifurandione-based material comprising the following mass fractions of components: Benzodifurandione-based substances 0.6wt% Poly(2-ethyl-2-oxazoline) 2.0wt% Isopropyl alcohol balance.

[0055] The method for producing the electron transport conductive ink containing the above-mentioned benzodifurandione-based substance is as follows.

[0056] [ka]

[0057] 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-2-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 protected with nitrogen gas. After stirring at 80 °C for 4 h, the mixture was cooled to room temperature and placed in a pre-treated permeation bag (10 kDa molecular weight cutoff). The solution was dialyzed against DMSO for 3 days, followed by dialysis against isopropyl alcohol. The solution in the permeation bag was then collected and filtered through an organic polytetrafluoroethylene filter head (1 μm) to obtain an electron-transporting conductive polymer ink processable in isopropyl alcohol. The solids content of the resulting solution was 2.6 wt%.

[0058] Poly(2-ethyl-2-oxazoline) (Mn 100,000-250,000 Da) was purchased from Macklin Reagent Company.

[0059] Example 5

[0060] An electron transport conductive ink comprising a benzodifurandione-based material comprising the following mass fractions of components: Benzodifurandione-based substances 0.65wt% Poly(2-ethyl-2-oxazoline) 4.15wt% Isopropyl alcohol balance.

[0061] The method for producing the electron transport conductive ink containing the above-mentioned benzodifurandione-based substance is as follows.

[0062] [ka]

[0063] 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-2-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 protected with nitrogen gas. After stirring at 80 °C for 4 h, the mixture was cooled to room temperature and placed in a pre-treated permeation bag (10 kDa molecular weight cutoff). The solution was first dialyzed against DMSO for 3 days, followed by dialysis with isopropyl alcohol. The solution in the permeation bag was then collected and filtered through an organic polytetrafluoroethylene filter head (0.45 μm) to obtain an electron-transporting conductive polymer ink processable with isopropyl alcohol solutions of different particle sizes. The solids content of the resulting solution was 4.8 wt%.

[0064] Poly(2-ethyl-2-oxazoline) (Mn 100,000-250,000 Da) was purchased from Macklin Reagent Company.

[0065] Example 6

[0066] Dodecyldimethylsulfopropylbetaine was further added to the conductive ink prepared in Example 5 to produce an electron transport conductive ink with a low work function that can be processed in an alcohol solution. The procedure is as follows:

[0067] 50 mL of the conductive ink prepared in Example 5 was taken, and 720 mg of dodecyldimethylsulfopropylbetaine (35 wt% of the benzodifurandione-based substance) was added. The mixture was stirred at room temperature for 30 minutes, then homogenized for 10 minutes and filtered through an organic polytetrafluoroethylene filter head (0.45 μm) to obtain an electron transport conductive ink with a low work function that can be processed in alcohol solution. The work function was measured with a Kelvin probe to be 4.15 eV. Furthermore, the work function range could be further adjusted by controlling the amount of dodecyldimethylsulfopropylbetaine added, as shown in Figure 5.

[0068] Example 7

[0069] 2-(2'-hydroxy-5'-methylphenyl)-benzotriazole was further added to the conductive ink prepared in Example 6 to produce an electron transport conductive ink that is UV-resistant, has a low work function, and can be processed in an alcohol solution. The procedure is as follows.

[0070] 50 mL of the conductive ink prepared in Example 6 was taken, and 120 mg of 2-(2'-hydroxy-5'-methylphenyl)-benzotriazole (5 wt% of the benzodifurandione-based substance added) was added. The mixture was stirred at room temperature for 30 minutes, then homogenized in a homogenizer for 10 minutes and filtered through an organic polytetrafluoroethylene filter head (0.45 μm) to obtain an electron transport conductive ink that is UV-resistant, has a low work function, and can be processed in an alcohol solution.

[0071] Comparative Example 1

[0072] In this comparative example, no additional surfactant was added. The specific procedure was as follows.

[0073] 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 protected with nitrogen gas. After stirring at 80 °C for 6 h, the solution was returned to room temperature and placed in a pre-treated permeation bag (10 kDa molecular weight cutoff). The solution was first dialyzed against DMSO for 3 days, followed by ethanol dialysis. During dialysis, as DMSO was replaced by ethanol, the prepared polybenzodifurandione precipitated as a solid in the permeation bag, making it impossible to obtain a conductive polymer ink processable with ethanol.

[0074] Comparative Example 2

[0075] In this comparative example, a low molecular weight surfactant, F127, was used. The specific procedure is as follows:

[0076] 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 = 5,000 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 protected with nitrogen gas. After stirring at 80 °C for 4 h, the mixture was cooled to room temperature and placed in a pre-treated permeation bag (10 kDa molecular weight cutoff). The solution was first dialyzed against DMSO for 3 days, followed by aqueous dialysis. The solution in the permeation bag was then collected and filtered through a polyethersulfone aqueous filter head (0.45 μm). However, the resulting solution failed to pass through this filter head, making it impossible to obtain an electron-transporting conductive polymer ink processable in aqueous solution.

[0077] Comparative Example 3

[0078] In this comparative example, an equal mass of polydiallyldimethylammonium chloride was used as a surfactant instead of polyether F127 in Example 1. The specific procedure was as follows.

[0079] 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 (total volume 40 mL). The solution was degassed under vacuum and protected with nitrogen gas. After stirring at 80 °C for 4 h, the mixture was cooled to room temperature and placed in a pre-treated permeation bag (molecular weight cutoff: 10 kDa). The mixture was first dialyzed against DMSO for 3 days, followed by aqueous dialysis. The resulting mixture gradually precipitated as a solid in the permeation bag during the solvent exchange process, making it impossible to obtain an electron-transporting conductive polymer ink processable in aqueous solution.

[0080] Test Example 1

[0081] The liquids prepared in Examples 1 to 5 and Comparative Example 2 were spin-coated, and the conductivity of the resulting thin films was measured using a four-point probe method. This demonstrates the high conductivity properties of the electron transport conductive inks proposed in this invention that can be processed using a water / alcohol solution.

[0082] The test conditions were as follows: glass substrates were washed with deionized water, acetone, and isopropyl alcohol, respectively, and then dried in an oven at 60°C. The corresponding liquids were then spin-coated onto the washed glass substrates at 2,000 rpm to obtain thin films. The sheet resistance of the thin films was measured using a HELPASS four-point resistivity measuring instrument HPS2663, and the thickness of the resulting thin films was measured using a step gauge. The resulting thin films could be significantly adjusted by changing the surfactant and its amount.

[0083] [Table 1]

[0084] These data demonstrate that the resulting thin films can be significantly tuned by varying the surfactant and the amount used.

[0085] Test Example 2

[0086] The electron transport conductive ink prepared in Example 4 was spin-coated onto a film, and different temperatures were applied to both sides of the thin film to measure the Seebeck coefficient of the resulting material. Combined with the conductivity measured in Test Example 1, the calculated power factor was 195 μWm -1 K -2 This demonstrates the application of the proposed water / alcohol solution processable electron transport conductive ink to n-type thermoelectric devices.

[0087] [Table 2]

[0088] Test Example 3

[0089] The low work function, alcohol-processable electron-transporting conductive ink prepared in Example 6 was used to fabricate an electron-transporting layer for an organic solar cell, thereby demonstrating the use of the conductive ink of the present invention as an electron-transporting material in an organic photovoltaic device. The structure of the organic solar cell device was ITO (20 nm) / PEDOT:PSS (40 nm) / PM6:Y6 (1:1.5, m / m, 100 nm) / electron-transporting layer (10-150 nm) / silver electrode (80 nm). The structure is shown in Figure 6. The device fabrication process is as follows:

[0090] Indium tin oxide (ITO)-plated glass substrates were washed with deionized water, acetone, and isopropyl alcohol and dried in an oven at 60 °C. Then, a 40 nm thick film of poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS, CLEVIOS PVP Al 4083) was spin-coated onto the cleaned ITO glass substrates and heated on a heating platform at 140 °C for 15 min in air. The active layer, consisting of the conjugated polymer PM6 (electron donor material) and Y6 (electron acceptor material), was weighed into a clean bottle (1:1.5, m / m) and transferred to a nitrogen-protected glovebox (purchased from VAC). The active layer was then dissolved in chloroform containing 1 wt% 1,8-diiodooctane. A 100 nm thick film was spin-coated onto the PEDOT:PSS film using a rotary homogenizer and profilometer. The low-work-function, alcohol-processable electron-transport conductive ink obtained in Example 6 was diluted with isopropyl alcohol to different concentrations and spin-coated onto the active layer to prepare an electron-transport layer with a thickness ranging from 10 to 100 nm. The thin film was then transferred to a vacuum deposition chamber connected to a glove box, and a mask plate was used to cover the active layer with a thickness of approximately 10 nm. -7 Silver (80 nm) electrodes were evaporated under the conditions of 0.1 Pa.

[0091] The solar-simulated energy was measured at 100 mW / cm using a silicon photodiode and KG5 filter, which were calibrated at the National Renewable Energy Laboratory (NREL) before testing. 2 The energy conversion efficiency of the device was measured using a standard solar spectrum AM1.5 solar simulator (model no. 91192, Oriel, USA), and the photon and non-irradiated carrier density-voltage (JV) characteristics of the solar cell device were recorded using a Keithley 2410 and a Keithley 236 source meter, respectively.

[0092] In addition, in this example, a comparative example was provided in which the conductive ink of the present invention was not used, i.e., a comparative example without an electron transport layer. The relationship between the current density and voltage due to light irradiation of the element is shown in Figure 7, and the specific element efficiency is shown in Table 3.

[0093] FIG. 8 shows the chemical structures of the electron donor material PM6 and the electron acceptor material Y6 of the anode buffer material according to the example.

[0094] [Table 3]

[0095] From the above data, it can be seen that the electron transport conductive ink prepared in this invention can be used as an electron transport layer to significantly improve device performance and has excellent thickness insensitive properties.

[0096] Test Example 4

[0097] The alcohol-processable electron transport conductive ink prepared in Example 4 was spin-coated onto a film, which was then annealed in an inert atmosphere at different temperatures for 30 minutes, and the conductivity was measured. This shows that the thin films formed from the conductive ink of the present invention have excellent thermal stability and can further crystallize after heating to achieve different conductivities. The test results are shown in Table 4.

[0098] [Table 4]

[0099] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments set forth above, and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics thereof. Therefore, in all respects, the examples are intended to be illustrative and not limiting. The scope of the present invention is defined by the appended claims, rather than the foregoing description, and all changes that come within the meaning and range of equivalency of the claims are intended to be embraced therein.

[0100] Although this specification is described according to the embodiments, each embodiment does not necessarily include only one independent technical means. This description in this specification is for the purpose of clarity, and those skilled in the art should understand the specification as a whole, and may appropriately combine the technical means in each embodiment to form other embodiments that are understandable to those skilled in the art.

Claims

1. An electron transport type conductive ink containing a benzodifuran-based substance, the electron transport type conductive ink containing a benzodifuran-based substance comprising a benzodifuran-based substance, a specific surfactant and a solvent, The benzodifurandione-based substance has the following structural units: 【Chemistry 1】 where m, n, and k are positive integers, Y is a counter ion in the structure, and is one selected from an organic cation or an inorganic cation; the specific surfactant is selected from an anionic surfactant, a cationic surfactant, a nonionic surfactant, or an amphoteric surfactant; The electron transport conductive ink containing a benzodifuran-based substance is characterized in that the solvent is one or more selected from the group consisting of water and alcohol-based solvents.

2. The electron transport conductive ink containing the benzodifurandione-based material comprises the following mass fractions of components: Benzodifurandione-based substances: 0.2 to 1 wt% Specific surfactant 1 to 6 wt% Solvent Remainder 2. An electron transport conductive ink comprising the benzodifurandione substance according to claim 1.

3. 2. The electron transport conductive ink containing a benzodifuran-based material according to claim 1, wherein the specific surfactant is selected from surfactants capable of forming hydrogen bonds with the benzodifuran-based material.

4. 2. The electron transport conductive ink containing a benzodifuran-based substance according to claim 1, wherein the specific surfactant is a polymer having one or more of an ether group, an amide group, an ester group, or a carbonyl group.

5. The electron transport conductive ink containing a benzodifuran-based substance according to claim 4, characterized in that the specific surfactant is one or more selected from polyether-based derivatives, polylactic acid-based derivatives, polyacrylic acid-based derivatives, polyacrylamide-based derivatives, polyamide-based derivatives, imidazole-based polymer derivatives, thiazole-based polymer derivatives, oxazole-based polymer derivatives, and any divalent or polyvalent polymers thereof and their derivatives.

6. The electron transport type conductive ink containing the benzodifuran-based substance according to claim 1, characterized in that the electron transport type conductive ink containing the benzodifuran-based substance is composed of a solid and liquid composition, and the solid content accounts for 0.1 to 20 wt % of the electron transport type conductive ink containing the benzodifuran-based substance.

7. the liquid composition includes one or more of a UV stabilizer, a crosslinking agent, a work function adjuster, a preservative, a thickener, and a solubilizing agent; 7. The electron transport conductive ink containing a benzodifuran-based substance according to claim 6, wherein the solubilizing agent is one or more selected from the group consisting of nitrile-based solvents, ether-based solvents, ester-based solvents, sulfoxide-based solvents, ketone-based solvents, and amide-based solvents.

8. 2. The electron transport conductive ink containing a benzodifuran-based substance according to claim 1, wherein the specific surfactant has a number average molecular weight of 5 kDa to 500 kDa.

9. A method for producing an electron transport conductive ink containing a benzodifurandione-based substance according to any one of claims 1 to 8, characterized in that after production of the benzodifurandione-based substance is completed, the original polar solvent is replaced with the solvent.

10. Use of an electron transport conductive ink comprising the benzodifurandione material according to any one of claims 1 to 8 in the field of optoelectronics.

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