Stabilized water-based ink comprising n-type conducting polymer and a method for obtaining such an ink

Abstract

The present invention relates to a water-based ink comprising an n-type conducting polymer and an ink solvent comprising at least 90% water, wherein said ink further comprises a stabilizer being a zwitter ion, a neutral surfactant or a combination thereof.

Description

[0001] STABILIZED WATER-BASED INK COMPRISING N-TYPE CONDUCTING POLYMER AND A METHOD FOR OBTAINING SUCH AN INK

[0002] TECHNICAL FIELD

[0003] The present invention relates to a stabilized water-based ink comprising n- type conducting polymer and a method for obtaining such an ink.

[0004] BACKGROUND OF THE INVENTION

[0005] Water-based conducting polymer inks have broad industrial applications, such as antistatic coatings, polymer capacitors, organic solar cells, displays (LCD / OLED), and printed electronics. PEDOT:PSS is a commercially available p-type (hole-transporting) water-based conducting polymer ink with a pristine electrical conductivity > 1 S cm-1, reaching values > 4000 S cm-1after secondary doping or posttreating. However, water-based n-type (electron-transporting) conducting polymers are crucial when considering complementary components in semiconducting devices and circuitry.

[0006] Notably, several pioneering works have explored the processing of n-type conducting polymer in green solvents through methods such as hydrophilic side chain engineering, self-doping, and polymer dopants. However, these approaches have generally yielded electrical conductivity bellow 8 S cnr1. To address this challenge, previous work of the applicant reported the synthesis and processing of PDADF in water, achieving an electrical conductivity 66 S cnr1based on the poly(benzodifurandione) (PBFDO) backbone. However, this value remains two orders of magnitude lower than that of PBFDO (-2000 S cnr1), likely due to polymerization degree and defect formation. Moreover, PBFDO can only be processed in health harmful solvent DMSO, which limits its scalability for large-scale printing electronics. Despite all these efforts, the electrical conductivity of n-type polymers in green solventwater, still lags significantly behind that of p-type materials like PEDOT:PSS.

[0007] The BBL: PEI ethanol-based inks reported in WO 2022 / 106017 and WO 2022 / 106018 are the first step towards n-type inks comprising environmentally friendly solvents. However, there are several problems partially limiting their application. First of all, ethanol has strict requirements for fire prevention during production, transportation, storage, and usage. Further, the inks disclosed in the above-referenced applications are mainly limited to deposition methods such as spray-casting, spincasting and the like due to the large particle size. As may be gleaned from the abovecited references, the highest electrical conductivity of BBL: PEI inks is below 10 S cm-1, which make them unsuitable for devices sensitive to sheet resistance.

[0008] Recently, Fei Huang et al. reported a solution-processed n-type conducting polymer poly(benzodifurandione) (PBFDO) with electrical conductivity over 2000 S cm-1(Nature, 2022, s41586-022-05295-8). PBFDO is polymerized and processed in dimethyl formamide (DMF) or dimethyl sulfoxide (DMSO), solvents that are hard to print in an industrial setting, and that suffer from a disadvantage of being environmentally harmful.

[0009] It has been shown that PBFDO DMSO ink can undergo dialysis in water thus providing PBFDO water ink. However, such an ink lacks stability, showing an increasing amount of dedoped PBFDO and decreasing electrical conductivity during prolonged storage.

[0010] Considering the above, there is a need for developing an ink comprising an n-type conducting polymer and an environmentally benign solvent, such as water, wherein the ink is stable during storage and provides high conductivity.

[0011] SUMMARY OF THE INVENTION

[0012] Considering the above, the present invention aims to solve the problems of the prior art. To this end, the present invention relates to a water-based ink comprising an n-type conducting polymer and an ink solvent comprising at least 90% water. The water-based ink according to the present invention further comprises a stabilizer being a zwitter ion, a neutral surfactant or a combination thereof. The n-type conducting polymer according to the present invention may be water-soluble.

[0013] The n-type conducting polymer may be poly(benzodifurandione) (PBFDO) and derivatives thereof. PBFDO has the following structure:

[0014] wherein n is an integer from 2 to 10000.

[0015] By the term “derivatives of PBFDO” is understood a polymer having the following structure: wherein at least one of z, m and n is greater than 0, wherein x=0-100, y=0- 100, and wherein the building blocks are arranged in any order. In particular, only one of z, m and n may be greater than 0. For instance, z may be in the range from 1 to 100, while m and n may be in the range from 0 to 100. Alternatively, all three of z, m and n may be greater than 0, such as z=1-100, m=1-100 and n=1-100.

[0016] The n-type conducting polymer being a derivative of PBFDO and described above thus comprises a building block A having the structure: building block B having the structure: building block C having the structure: building block D having the structure: building block E having the structure:

[0017] The building blocks A-E may be arranged in any order. In other words, many possible arrangements of the building blocks are possible. For instance, the building blocks may be arranged in the orders A-B-C-D-E, A-C-B-D-E, E-B-C-D-A, B-C-A-D-E- C-A-C-D and so forth. Building blocks D may be attached to each other in three possible ways as depicted below.

[0018] It should be noted that building block E is obtained by oxidation of two building blocks D in the left structure above.

[0019] It should be noted that x, y, z, m and n are integers that may have the same or different values. Since at least one of z, m and n is greater than 0, at least one of the building blocks C, D and E is always present. Examples of possible polymer structures are given below.

[0020]

[0021] The carboxylic groups above may be at least partially deprotonated and bear ions selected from the group consisting of alkali metals, alkaline earth metals, Fe, Ni, Co, tetraalkylammonium, 1 ,3-alkylimidazolium, n-alkyl-pyridinium or the like. In particular, the ions may be selected from a group consisting of Li+, Na+, K+, Me4N+, BU4N+.

[0022] It should also be noted that by derivative thereof is further understood polymers having the following structure:

[0023] R = H, alkyl, aryl, etc

[0024] The stabilizer may be a zwitter ion. A zwitter-ion, also referred to as inner salt, may comprise a sulphonate group and an ammonium group. The zwitter ion may be a sulfobetain.

[0025] In particular, the zwitter-ion may be selected from a group consisting of 3- (N,N-Dimethylmyristylammonio)propanesulfonate (SB3-14), 3-(N,N-

[0026] Dimethylpalmitylammonio)propanesulfonate (SB3-16), 3-(1-Pyridino)-1 -propane Sulfonate (NDSB-201), 3-[Dimethyl-(2-hydroxyethyl)ammonio]-1 -propanesulfonate (NDSB-211), 3-(N-Phenylmethyl-N,N-dimethylammonio)propanesulfonate (NDSB- 256), 3-[N,N-Dimethyl(3-myristoylaminopropyl)ammonio]propanesulfonate (ASB-14), (TPPS), (DMAPS) or mixtures thereof, as depicted below.

[0027] Preferably, the zwitter-ion is 3-(N,N-

[0028] Dimethylmyristylammonio)propanesulfonate (SB3-14), 3-(N,N-

[0029] Dimethylpalmitylammonio)propanesulfonate (SB3-16) or a mixture thereof.

[0030] Further, the zwitter ion may be selected from the group consisting of:

[0031]

[0032] Taurine L-carnitine Ectoine

[0033] DSPEA

[0034] Stachydrine

[0035] Creatine

[0036] Cetyl hydroxysultaine Stearyl hydroxysultaine Stearyl betaine

[0037] Lauramine oxide Dimethyloleylamineoxide

[0038] Myristamine oxide 16:0 Lyso PC

[0039] Stearamine oxide

[0040]

[0041] 3-((2-Aminoethyl)-dimethylammonio) propane-1 -sulfonate

[0042] Myristyl hydroxysultaine

[0043]

[0044] The stabilizer may further be a neutral surfactant, such as a surfactant selected from but not limited to the group below. Further, the stabilizer may be a combination of a zwitter ion and a neutral surfactant.

[0045] As mentioned above, the ink solvent comprises at least 90% water, which implies that the water-based ink according to the present invention is environmentally benign, cost-efficient and easy to manufacture, transport and use. Preferably, the ink solvent comprises at least 99% water, such as 100% water.

[0046] The ratio between the n-type conducting polymer and the stabilizer may be from 1 :0.1 to 1 :2, preferably from 1 :0.5 to 1 :1.5, and most preferably from 0.8 to 1 :1.2, based on the repeating unit of the n-type conducting polymer. In particular, the ratio between the n-type conducting polymer and the stabilizer may be 1 :1 .

[0047] Concentration of the n-type conducting polymer in the ink may be 0.1-100 mg / ml, preferably 0.1-10 mg / ml, more preferably 1 mg / ml to 10 mg / ml.

[0048] The present invention further relates to a method for manufacturing a waterbased ink comprising an n-type conducting polymer. The method according got the present invention comprises the steps of: a) providing a first solution of an n-type conducting polymer in a first solvent; b) dialysing the first solution in an ink solvent comprising at least 90% of water, thus obtaining a second solution comprising the n-type conducting polymer and the ink solvent; c) adding a stabilizer selected from zwitter ions, neutral surfactants or a combination thereof to the second solution, thus obtaining the water-based ink.

[0049] As mentioned above, the n-type conducting polymer may be poly(benzodifurandione) (PBFDO) and derivatives thereof.

[0050] PBFDO may be manufactured by any method known in the art, including (i) polymerization of 3, 7-dihydrobenzo[1 ,2-b:4,5-b']difuran-2, 6-dione (HBFDO) in DMSO using 2,3,5,6-tetramethyl-1 ,4-benzoquinone (TMQ) as catalyst (Huang et al.), (ii) solvent-promoted polymerization in DMSO activated with acetic anhydride (AC2O) (Liu et al.), (iii) copper-catalyzed cascade oxidative polymerization (Zhang et al.), (iv) transition-metal-oxide-catalyzed polymerization (e.q. selenium dioxide, molybdenum trioxide) (Li et al.) and (v) iron oxide Fe2Oa (Ting et al.)

[0051] The first solvent may be a polar aprotic solvent. The polar aprotic solvent may be dimethyl sulfoxide (DMSO), dimethyl formamide (DMF), dimethyl acetamide (DMA) or a combination thereof.

[0052] The ratio between the first solvent and the ink solvent during step b) may be from 1 :10 to 1 :50. Step b) may be repeated several times by letting the first solution to dialyse and then replacing the ink solvent by a fresh portion of the ink solvent. By such an approach, it is ensured that the first solvent is replaced by the ink solvent completely.

[0053] The ratio between the n-type conducting polymer and the stabilizer may be from 1 :0.1 to 1 :2, based on the repeating unit of the n-type conducting polymer.

[0054] As mentioned above, the stabilizer may be a zwitter ion, in particular but not limited to a zwitter ion comprising a sulphonate group and an ammonium group. Further, the stabilizer may be a neutral surfactant, or a combination of a neutral surfactant and a zwitter ion.

[0055] As mentioned above, the n-type water-based conducting ink according to the present invention may be used in manufacturing of an organic electronic device. Such an organic electronic device may be an organic electrochemical transistor (OECT), a thermoelectric device, a ternary logic inverter, a solar cell, a photodiode, an organic light emitting diode (OLED), a capacitor, a battery, a fuel cell, a sensor or a memory.

[0056] BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Embodiments of the invention will now be described by way of example with reference to the accompanying drawings, of which:

[0058] Fig. 1 shows a scheme of PBFDO synthesis route and processing method to water; Fig. 2 a) UV-vis-NIR spectrum of PBFDO (H2O) over time compared with PBFDO (DMSO). b) Scheme of zwitterions, c) UV-vis-NIR spectrum of PBFDO (ZW) over time, d) Absorbance at 500 nm of PBFDO (H2O) with zwitterions, e) Absorbance at 845 nm of PBFDO (H2O) with zwitterions;

[0059] Fig. 3 depicts absorbance spectroelectrochemistry of PBFDO film on FTO, 0.1 M NaCI as the electrolyte;

[0060] Fig. 4a-e illustrate UV-vis-NIR spectra of PBFDO (H2O) ink with the addition of different zwitterions;

[0061] Fig. 5a-c depicts XPS 0(1 s) spectra of films obtained from: a. PBFDO (DMSO), b. PBFDO (H2O) ink, c. PBFDO (ZW) ink;

[0062] Fig. 6 shows FTIR spectra of PBFDO obtained from water ink over time;

[0063] Fig. 7 illustrates UV-vis-NIR spectra of different inks: a. PBFDO (DMSO) ink bubbled with oxygen, b. PBFDO (DMSO) mixed with different amount of water, c. Absorbance at 500 nm of PBFDO (H2O) and PBFDO (ZW) in various gas environments, d. Absorbance at 845 nm of PBFDO (H2O) and PBFDO (ZW) in various gas environments;

[0064] Fig. 8a-f depicts UV-vis-NIR spectra of PBFDO DMSO mixed with different amount of water;

[0065] Fig. 9a-f shows PBFDO (H2O) and PBFDO (ZW) ink stored in different conditions;

[0066] Fig. 10 illustrates: a, b 2D GIWAXS patterns, c out-of-plane and in-plane line cuts of GIWAXS, d, e AFM images of PBFDO (H2O) and PBFDO (ZW);

[0067] Fig. 11a-b depicts 2D image of GIWAXS: a. PBFDO (ZW) film without washing; b. ZW film;

[0068] Fig. 12a-d shows Lorentz peak fitting of 1 D GIWAXS data;

[0069] Fig. 13 illustrates: a. Conductivity, b. Seebeck coefficient, c. Power factor over time of PBFDO (H2O) and PBFDO (ZW); Fig. 14a-f shows Seebeck coefficient of PBFDO (ZW) ink over time;

[0070] Fig. 15a-f depicts Seebeck coefficient of PBFDO (H2O) ink over time.

[0071] DETAILED DESCRIPTION OF THE INVENTION

[0072] As mentioned above, the present invention relates to a water-based ink comprising an n-type conducting polymer and an ink solvent comprising at least 90% water. The water-based ink according to the present invention further comprises a zwitter-ion.

[0073] The invention is exemplified by a PBFDO water-based ink [PBFDO (H2O)] that can be obtained by a one-step solvent exchange process through dialysis against water (Figure 1a). However, the PBFDO nanoparticles in water tend to dedope in the ink formulation, leading to the decreased of electrical conductivity when stored in ambient condition. To address this issue, various additives were incorporated into PBFDO (H2O) ink, demonstrating that the addition of zwitterions stabilized the waterbased ink (Fig. 2b). Among the zwitterions tested, SB3-14 (ZW) exhibits the best performance. This novel approach resulted in a PBFDO water ink stabilized in water for 161 days, showcasing the remarkable conductivity up to 1370 ± 82 S cm-1, among the highest reported for n-type polymers processed in water and other green solvents. Notably, the maximum power factor of the PBFDO processed from water was up to 184 pW rrr1K'2.

[0074] To obtain PBFDO (H2O) ink, the PBFDO (DMSO) ink, synthesized from previous reported method by Huang et al. was dialyzed in deionized water for 3 days according to the following procedure. The PBFDO (DMSO) ink (5 mg / mL, around 60 mL) was dialyzed against deionized water (1 L, replaced daily) for 3 days, thus removing DMSO almost entirely. The polymer solution in the dialysis bag was concentrated by rotary evaporation and filtered using a 1 pm GMF filter, yielding PBFDO (H2O) ink. The final concentration was determined by measuring the mass of PBFDO solid after drying 1 mL of ink, approximately 6 mg / mL.

[0075] It was found that PBFDO could be dispersed in water via solvent exchange, forming a water-based PBFDO ink. However, the initially black PBFDO (H2O) ink turned amaranth after being stored at ambient for 2 months. To investigate this change, ultraviolet-visible-near-infrared (UV-vis-NIR) absorption spectra of the solution were measured over time as shown in Figure 2a. The initial PBFDO (H2O) displayed the more pronounced peak at 500 nm and 845 nm, assigned to the dedoped PBFDO (Figure 3), demonstrating that dedoping occurred during the dialysis against water. The normalized absorbance of these dedoping peaks (500 nm and 845 nm) significantly increased in the first two month and then stabilized after four months (Figure 2a).

[0076] The UV-vis-NIR spectra of different zwitterions were measured in terms of storage time, demonstrating that zwitterions can inhibit PBFDO dedoping process in water-based ink (Figure 4a-e), with ZW showing the most significant inhibition effect (Figure 2c). For qualitative analysis, the neutral peaks of dedoped PBFDO at 500 nm and 845 nm were monitored over time. The peak at 500 nm indicated that zwitterions with longer hydrophobic side chains, such as ZW and ASB-14, provided better inhibition of the dedoping process, while all tested zwitterions exhibited some inhibitory effect (Figure 2d). The absorbance change at 845 nm showed a similar trend across the different zwitterions (Figure 2e). In addition, X-ray photoelectron spectroscopy (XPS) was performed to further investigate the dedoping process. The peak at 534.4 eV of XPS 0(1 s) spectra of pristine PBFDO which corresponds to doped state of PBFDO accounts for 37% of the carbonyl groups, as shown in Figure 5a. In comparison, the same peak in PBFDO (H2O) ink stored for 65 days decreased significantly to approximately 15% (Figure 5b), indicating substantial dedoping over time. However, in the case of PBFDO (ZW) ink stored for 65 days, the doping peak remained at 26% (Figure 5c), suggesting that the addition of ZW effectively slows down the dedoping process, as indicated by the almost unchanged area of the peak at 534.4 eV.

[0077] Then, the structure of PBFDO obtained from the water-based ink was characterized using Fourier-transformed infrared (FTIR) spectroscopy. The FTIR spectra of PBFDO obtained from the water ink over time showed identical absorption features to those of PBFDO made from DMSO ink (Figure 6). This excluded the alterations in the polymer structure. Fourier-transformed infrared (FTIR) spectra samples were prepared by evaporating solvent on a 40°C hotplate to form a solid sample, then measured with PerkinElmer Spectron 3 in ATR mode.

[0078] Further control experiments involved storing PBFDO (H2O) and PBFDO (ZW) inks in ambient air, oxygen, and argon. The characteristic dedoping peak at 500 nm indicated that PBFDO (H2O) in ambient air and argon had similar absorption but increased under oxygen (top line in Figure 7c). In stark contrast, ZW showed outstanding inhibition, with no significant increase within 20 days even in an oxygen environment. The absorbance change at 845 nm followed a similar trend, confirming oxygen's significant role in dedoping (Figure 7d and Figure 9a-f). Building upon the analysis of the aforementioned data, the inventors propose that PBFDO nanoparticles can be dedoped by oxygen in the water ink formulation. However, the dedoping process is significantly inhibited when ZW is added to the water ink.

[0079] The ultraviolet-visible-near-infrared (UV-vis-NIR) absorption spectroscopy measurements were performed using a Perkin Elmer Lambda. Unless otherwise noted, the UV-vis-NIR spectra were measured from the diluted water solution samples (0.1 mg / mL). Spectroelectrochemistry measurements were conducted using a the Potentiostat BioLogic SP-200 with a 0.1 M NaCI aqueous solution as the electrolyte. PBFDO thin film was casted on FTO and served as the working electrode, where the Ag / AgCI as the reference electrode and platinum wire the counter electrode. For each voltage step, the potential was held constant for 300 s before measuring the UV-vis- NIR spectra.

[0080] Microstructure of PBFDO films obtained from PBFDO (H2O) and PBFDO (ZW) was characterized by grazing incidence wide-angle X-ray scattering (GIWAXS). The 2D images of GIWAXS reveal that both films have an edge-on orientation with respect to the substrates (Figure 10a and 10b), and no ZW remains after the film washed with acetone (Figure 11a-b). PBFDO (H2O) film exhibits a strong TT-TT stacking (010) signal at qxy = 1.85 A-1 (d-spacing = 3.39 A) and lamellar (100) peak at qz = 0.58 A-1 (d-spacing = 10.79 A). In contrast, PBFDO (ZW) washed films show a TT-TT stacking value of 3.33 A and larger lamellar stacking (d-spacing = 12.09 A), leading to higher TT-TT stacking crystallinity with longer coherence lengths and lower paracrystalline disorder (Figure 10c, Figure 12a-d and Table 3). Atom force microscopy (AFM) reveals that PBFDO (ZW) film exhibits a smooth and uniform film morphology, with a roughness around 1.22 nm (Figure 10e). On the contrary, without addition of ZW, PBFDO (H2O) forms a less uniform film with some cracks which might explain its lower conductivity (vide infra). For obtaining thin films, PBFDO (H2O) and PBFDO (ZW) solution was spin-casted (2000 rpm, 1 min, acceleration 2000 rpm s’1, then 3000 rpm, 10 s, acceleration 3000 rpm s-1) onto prewashed and plasma-cleaned substrates, such as glass, Au, FTO, and patterned Cr / Au on glass. The films were immediately annealed on a 200°C hotplate after spin-casting for 2 minutes. PBFDO (ZW) films were submerged into acetone for 30 min to remove the ZW residuals, then dried with nitrogen gun. Film thickness was measured by Dektak XT Bruker.

[0081] Grazing-incidence wide-angle X-ray scattering (GIWAXS) experiments were conducted at 9A ll-SAXS beamline of the Pohang Accelerator Laboratory in South Korea. The beam energy was 11.07 KeV and incident angle was 0.12°. Atomic force microscope (AFM) images were recorded with an Icon XR from Bruker, using a silicon nitride cantilever with a spring constant of 40 N nr1. The Zeta potential of the solutions was characterized by dynamic light scattering at Zetasizer Nano ZS90 (laser wavelength = 632.8 nm) at room temperature. XPS was performed with a Scienta-200 hemispherical analyzer using monochromatized Al Ka source with photon energy of 1486.6 eV. All photoelectron spectroscopy measurements were carried out with a base pressure lower than 1 *1 O'9mbar.

[0082] Table 3. Summary of the calculated TT-TT stacking and lamellar distances and FWHM of (010) and (100) peaks from GIWAXS 1 D data.

[0083] TT-TT stacking Lamellar stacking qxyqxyCoherenc Paracrystalli qzqzCoherence Paracrystalli

[0084] Polymer (010) (010)elength ne disorder (100) (100) length ne disorder s

[0085] (A1) (A) (A) (A) (A1) (A) (A) (A)

[0086] PBFDO 3.38 0.582 10.78

[0087] 1.8538 17.65 0.1649 14.94 0.3198

[0088] (H2O) 9 6 5

[0089] PBFDO 3.33 0.519 12.08

[0090] 1.8848 19.75 0.1544 17.62 0.3117

[0091] (ZW) 4 9 5

[0092] Next, the electrical and thermoelectric performance of the water-based ink according to the present invention over time was investigated. PBFDO (H2O) ink exhibits a decrease in electrical conductivity in the first two months and gradually tends to stabilize around 178 ± 34 S cm-1. In stark contrast, PBFDO (ZW) films exhibits an outstanding and stable conductivity up to 1370 ± 82 S cm-1over time, demonstrating the inhibition of dedoping using ZW (Figure 13a). The conductivity results are consistent with the UV-vis-NIR data in Figure 2a where the dedoping peaks at 500 nm and 845 nm intends to be stable after 112 days. The Seebeck coefficient (S) of the film obtained from each ink has a slight change within 90 days (Figure 13b and Figure 14a-f and 15a-f), but has a greater absolute value compared to pure PBFDO obtained from DMSO ink. However, the SPBFDO <Z ) shows a drop after 90 days compared to SPBFDO <H2O). Due to the change of Seebeck coefficient over time, the power factor (PF) of PBFDO (ZW) exhibits an increased PF over time and up to 165 pW nr1K'2when the ink was stored for 82 days (highest value is around 184 pW nr1K'2, stored for 50 days) (Figure 13c), and decrease in the next 80 days but still was around 100 pW nr1K'2. Note that most of n-type conjugated polymers with high PF necessitate the flammable or hazardous solvents such as chloroform, dichlorobenzene and dimethyl sulfoxide, limiting their usage in a large scale. In comparison, PBFDO (ZW) is fully water processable, exhibiting the highest conductivity and power factor among the solution processed n-type organic materials in green and non-green solvent (Table 4).

[0093] Electrical conductivity was measured by a four-point probe technique. The conductivity was calculated using the equation: o = IL / VWd, where W is the sample width, d is the film thickness, and L is the length between two electrodes (W = 4000 pm, L = 20 pm, and d is dependent on different samples). The Seebeck coefficients were measured inside the glovebox by a pair of Peltier elements to provide a temperature difference. All these measurements used a Keithley 4200-SCS semiconductor characterization system.

[0094] Table 4. Summary of solution-processed n-type conducting polymer, electrical conductivity (o), thermoelectric power factor (PF), and processing solvents. Regarding the solvent abbreviations, CB = chlorobenzene, CF = chloroform, HFIP = 1 ,1 ,1 ,3,3,3-Hexafluoro-2-propanol, ODCB = 1 ,2-dichlorobenzene, TECE = Tetrachloroethane, TCE = trichloroethylene, MSA = methanesulfonic acid, and Tol = toluene.

[0095] TBDOPV-T-518 N-DMBI 2023 114 200 ODCB f-BSeI2TEG-FT N-DMBI 2023 103.5 70.1 CF

[0096] BBL PCAT-K 2023 0.3 5 Water

[0097] PBFDO H+2022 2011 90 DMSO

[0098] PDTzTI-TEG N-DMBI 2022 34 15.7 ODCB

[0099] PFC1TVT PSpF 2022 4.2 67 ODCB

[0100] PDTz TP-DMBI 2021 11 15 ODCB

[0101] PC1BD TP-DMBI 2021 1 32 ODCB f-BTI2TEG-FT / PBTI N-DMBI 2021 116.3 65.7 CF

[0102] PFC1TVT N-DMBI 2021 38.3 22.7 ODCB

[0103] N-N N-DMBI 2021 0.65 3.2 ODCB

[0104] PBN-19 TDAE 2021 7.8 24.8 TECE

[0105] PBDOPVTT NDI-TBAF 2021 0.2 67 ODCB

[0106] PBDOPVTT N-DMBI 2021 8.1 21 ODCB

[0107] BBL PEI 2021 7.7 11 EtOH

[0108] TBDPPV N-DMBI 2020 85 76 ODCB

[0109] TBDOPV-T N-DMBI 2020 59 106 ODCB pNB-TzDP N-DMBI 2020 11.6 53.4 CB

[0110] FBDPPV TAM 2020 21 51 TCE / ODCB

[0111] BBL P(g42T-T) 2020 2 2.2 MSA

[0112] UFBDPPV TAM 2020 22.5 80 ODCB

[0113] PDTzTI TDAE 2019 4.6 7.6 CB

[0114] P(PzDPP-CT2) N-DMBI 2019 8.4 57.3 ODCB

[0115] FBDPPV (N-DMBI)22019 7.9 7 Tol

[0116] LPPV-1 N-DMBI 2019 1.1 1.96 ODCB / TCE

[0117] PDPF N-DMBI 2018 1.3 4.65 ODCB

[0118] P(NDI2OD-Tz2) TDAE 2018 0.1 1.5 CF

[0119] PNDI2TEG-2Tz N-DMBI 2018 1.8 4.6 CF

[0120] TEG-N2200 N-DMBI 2018 0.17 0.4 CF p(gNDI-gT2) N-DMBI 2018 0.3 0.4 CF

[0121] C1BDPPV TBAF 2017 0.62 0.63 CB

[0122] PNDTI-BBT-DP N-DMBI 2017 5 14 CF

[0123] FBDPPV N-DMBI 2015 14 28 ODCB

[0124] To summarize, water-based ink comprising an n-type conducting polymer and an ink solvent comprising at least 90% water, wherein said ink further comprises a zwitter-ion is provided through a simple dialysis process from a first solution of an n- type conducting polymer in a first solvent. To address the issue of dedoping and thus instability of the water-based ink, the addition of a zwitter ion, as exemplified by PBFDO (ZW) ink, resulted in conductivity up to 1370 ± 82 S cm-1and stability for over 161 days, achieving a maximum power factor about 184 pW nr1K'2, being among the highest values in n-type conducting polymers. The water-based ink and the method for manufacturing thereof as described above mark a significant advancement in the development of highly conductive n-type polymers processed in water, paving the way for more sustainable large-scale applications.

[0125] Although the present invention has been described with reference to various embodiments, those skilled in the art will recognize that changes may be made without departing from the scope of the invention. It is intended that the detailed description be regarded as illustrative and that the appended claims including all the equivalents are intended to define the scope of the invention.

Claims

CLAIMS1 . A water-based ink comprising an n-type conducting polymer and an ink solvent comprising at least 90% water, wherein said ink further comprises a stabilizer being a zwitter ion, a neutral surfactant or a combination thereof.

2. The water-based ink according to any one of the preceding claims, wherein said n-type conducting polymer is poly(benzodifurandione) (PBFDO) and derivatives thereof.

3. The water-based ink according to any one of the preceding claims, wherein said stabilizer is a zwitter-ion comprising a sulphonate group and an ammonium group.

4. The water-based ink according to claim 4, wherein said zwitter ion is a sulfobetain.

5. The water-based ink according to claim 4, wherein said zwitter-ion is selected from a group consisting of 3-(N,N-Dimethylmyristylammonio)propanesulfonate (SB3-14), 3-(N,N-Dimethylpalmitylammonio)propanesulfonate (SB3-16), 3-(1- Pyridino)-1 -propane Sulfonate (NDSB-201), 3-[Dimethyl-(2- hydroxyethyl)ammonio]-1-propanesulfonate (NDSB-211), 3-(N-Phenylmethyl- N,N-dimethylammonio)propanesulfonate (NDSB-256), 3-[N,N-Dimethyl(3- myristoylaminopropyl)ammonio]propanesulfonate (ASB-14), 3-(Triphenylphosphonio)propane-I -sulfonate (TPPS), [2-(Methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide, (DMAPS) or mixtures thereof.

6. The water-based ink according to any one of the preceding claims, wherein said ink solvent comprises at least 99% water.

7. The water-based ink according to any one of the preceding claims, wherein the ratio between said n-type conducting polymer and said stabilizer is from 1 :0.1 to 1:2, based on the repeating unit of the n-type conducting polymer.

8. The water-based ink according to any one of the preceding claims, wherein concentration of the n-type conducting polymer in said ink is 0.1-100 mg / ml, preferably 0.1-10 mg / ml, more preferablyl mg / ml to 10 mg / ml.

9. A method for manufacturing a water-based ink comprising an n-type conducting polymer, said method comprising the steps of: a) providing a first solution of an n-type conducting polymer in a first solvent; b) dialysing said first solution in an ink solvent comprising at least 90% of water, thus obtaining a second solution comprising said n-type conducting polymer and said ink solvent; c) adding a stabilizer being a zwitter ion, a neutral surfactant or a combination thereof to said second solution, thus obtaining said water-based ink.

10. The method according to claim 9, wherein said first solvent is a polar aprotic solvent.

11. The method according to claim 9 or 10, wherein the ratio between said first solvent and said ink solvent during step b) is from 1 : 10 to 1 :50.

12. The method according to any one of claims 9-11 , wherein the ratio between said n-type conducting polymer and said stabilizer is from 1:0.1 to 1 :2, based on the repeating unit of the n-type conducting polymer.

13. The method according to any one of claims 9-12, wherein said n-type conducting polymer is poly(benzodifurandione) (PBFDO) and derivatives thereof.

14. The method according to any one of claims 9-13, wherein said stabilizer is a zwitter ion.

15. The method according to any one of claims 9-14, wherein said zwitter-ion is selected from a group consisting of 3-(N,N- Dimethylmyristylammonio)propanesulfonate (SB3-14), 3-(N,N-Dimethylpalmitylammonio)propanesulfonate (SB3-16), 3-(1-Pyridino)-1- propane Sulfonate (NDSB-201), 3-[Dimethyl-(2-hydroxyethyl)ammonio]-1- propanesulfonate (NDSB-211), 3-(N-Phenylmethyl-N,N- dimethylammonio)propanesulfonate (NDSB-256), 3-[N,N-Dimethyl(3- myristoylaminopropyl)ammonio]propanesulfonate (ASB-14), 3-(Triphenylphosphonio)propane-I -sulfonate (TPPS), [2-(Methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide, (DMAPS) or mixtures thereof.

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