Method for obtaining water-processable n-type conducting polymers

Abstract

The present invention provides a method for producing a water-processable n-type conducting polymer, comprising the steps of: a) adding a monomer to a solvent system comprising water in the presence of a catalyst and a base to prepare a reaction solution; b) polymerizing the monomer in the reaction solution to obtain an n-type conductive polymer; c) post-treating the n-type conductive polymer dispersion to obtain a water-processable n-type conductive polymer; The present invention relates to a method comprising:

Description

[Technical Field]

[0001] The present invention relates to a method for producing a water-processable n-type conductive polymer that is polymerized from water, a water-processable n-type conductive polymer obtained by such a method, and a water-based ink comprising the water-processable n-type conductive polymer obtained by such a method. [Background technology]

[0002] Water-based conductive polymer (CP) inks have a wide range of industrial applications, including 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 conductive polymer ink with a pure electrical conductivity of 1 S cm. -1 and exceeds 4000 S cm by secondary doping or post-treatment. -1 They have reached values ​​exceeding 100%. Their success is largely due to their easy synthesis in water, exceptional aqueous processability, and outstanding electrical performance. Applications in areas such as bioelectronics and thermoelectric devices often require the complementary use of both p-type and n-type (electron transporting) materials. The availability of n-type materials suitable for aqueous polymerization and processing remains limited. However, waterborne n-type (electron transporting) conducting polymers become important when considering complementary components for semiconductor devices and circuits.

[0003] The BBL:PEI ethanol-based inks reported in WO 2022 / 106017 and WO 2022 / 106018 are a first step toward environmentally friendly solvent-based inks. However, there are several issues that partially limit their application. First, ethanol has strict requirements regarding fire prevention during production, transportation, storage, and use. Furthermore, the inks disclosed in the above applications are primarily limited to deposition methods such as spray casting, spin casting, and the like due to their large particle size. As can be seen from the above references, the maximum electrical conductivity of BBL:PEI inks is 10 S cm.-1 less than 1000 .mu.m and is not suitable for devices that are sensitive to sheet resistance.

[0004] Recently, Tang et al. synthesized poly(3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione) (PBFDO) in DMSO and demonstrated an unprecedented 1000 S cm for an n-type polymer. -1 This breakthrough achievement demonstrates electrical conductivity exceeding 1000 kJ / cm². Despite this excellent conductivity, the purification process of PBFDO requires large amounts of DMSO during the dialysis process. While this work marks a first step toward developing n-type conductive polymers processed with non-toxic solvents, its reliance on DMSO, a solvent known to have adverse health effects, highlights the need for alternative approaches. Water remains the preferred choice for the synthesis and processing of conductive inks for large-scale printed electronics, as it is the safest and most sustainable option.

[0005] The development of water-based n-type CP inks with high conductivity, processability, and stability comparable to PEDOT:PSS remains a challenging scientific and industrial endeavor with far-reaching implications for low-cost printed organic electronics. Summary of the Invention

[0006] In view of the above, the present invention aims to solve the problems of the prior art. To this end, the present invention provides a method for producing a water-processable n-type conducting polymer that is polymerized in water, comprising the steps of: a) adding a monomer to a solvent system comprising water in the presence of a catalyst and a base to prepare a reaction solution; b) polymerizing the monomer in the reaction solution to obtain an n-type conductive polymer dispersion; c) post-treating the n-type conductive polymer dispersion to obtain a water-processable n-type conductive polymer; The present invention relates to a method comprising the steps of:

[0007] It should be noted that a catalyst precursor is also formed along with the water-processable n-type conducting polymer, which can be easily separated from the water-processable n-type conducting polymer and recycled as described in more detail below.

[0008] The monomer has a centrosymmetric benzene ring as the backbone, an active hydrogen, and at least one electron-withdrawing group at the benzylic position, such as a carbonyl, carboxyl, amide, alkoxyacyl, or the like. [ka]

[0009] Furthermore, the monomer may be in the form of a heterocyclic moiety having a centrosymmetric benzene ring fused with at least one, preferably at least two, rings, preferably a five-membered ring. The monomer further comprises an active hydrogen and at least one electron-withdrawing group at the benzylic position. In particular, the monomer may be 3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione (HBFDO), 5,7-dihydropyrrolo[2,3-f]indole-2,6(1H,3H)-dione, or 3,7-dihydrobenzo[1,2-b:4,5-b']dithiophene-2,6-dione. [ka]

[0010] In particular, the monomer is 3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione (HBFDO). In such an embodiment, the n-type conductive polymer can be poly[(2,2'-(2,5-dihydroxy-1,4-phenylene)diacetic acid)-co-3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione] (PDADF), poly[(2,2'-(2,5-dihydroxy-1,4-phenylene)diacetic acid) (PDADF-P), or a mixture thereof. The structure of PDADF-P is similar to that of PDADF, but lacks the heterocyclic segment. In PDADF, m and n are integers that may be the same or different. The overall outline of the method of the present invention is summarized as follows: [ka] where AQ is a catalyst, as described in more detail below.

[0011] According to the present invention, the solvent system may consist of water. In other words, the solvent system may comprise substantially only water, e.g., at least 99% by volume (vol%). Such an embodiment offers the advantage of a cost-effective and environmentally friendly production method.

[0012] The catalyst of the present invention comprises a polar group. In particular, the catalyst of the present invention can be selected from carboxyl- and sulfonyl-substituted benzoquinones (AQs). In other words, the catalyst of the present invention comprises a benzoquinone core structure and at least one substituent comprising a carboxyl moiety (-COOH) or a sulfonyl moiety (-SO3H). It should be noted that the catalyst can comprise multiple substituents, which may be the same or different. The catalyst can be efficiently separated, recovered, and recycled after polymerization, consistently producing water-processable n-type conducting polymers with electrical performance similar to that of virgin, i.e., polymers produced using a non-recycled catalyst.

[0013] In particular, the catalyst has the following structure: [ka] wherein R0, R1, and R3 are independently H, Me, or —CH2R4R5COOH; R4 and R5 are independently H or Me; R2 is -COOH or -SO2OH) may have:

[0014] A particularly preferred catalyst is 3-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dien-1-yl)propanoic acid (TMQ-PA, R 0 =R 1 =R 3 R = Me, R = R = H, R = -COOH), 3,3'-(4,5-dimethyl-3,6-dioxocyclohexa-1,4-diene-1,2-diyl)dipropionic acid (AAMMQ, R = R = Me, R = -CHR RCOOH, R, R = H or Me, R = -COOH), 3,3'-(2,5-dimethyl-3,6-dioxocyclohexa-1,4-diene-1,4-diyl)dipropionic acid (AMAMQ, R = R = Me, R = -CHR RCOOH, R, R = H or Me, R = -COOH), and combinations thereof.

[0015] The base, i.e., proton acceptor, is added to the reaction solution simultaneously with the monomer and catalyst or immediately after the monomer and catalyst are added. The base is added to dissolve the catalyst in the solvent system. Alternatively, the catalyst and base may be added first and stirred for a few minutes, followed by the addition of the monomer. The base may be specifically MOH, where M is Li. + , Na + , K. + , Me4N + , Bu4N + or a combination thereof.

[0016] These catalysts, also called AQs, can be synthesized by a Michael addition reaction followed by oxidation with N-bromosuccinimide (NBS), as explained in detail below. AQs are highly crystalline, water-insoluble organic acids. However, when neutralized with a strong base, AQs become highly water-soluble [AQs]. - If the solvent system consists of water, [AQ] - can catalyze the polymerization of water-insoluble HBFDO monomer to water-processable PDADF. Notably, after polymerization, the aqueous solution becomes strongly acidic, and [AQs] - The advantage of this process is that PDADF inks can be easily recycled, with the advantages of being cost-effective and having low environmental impact.

[0017] The catalyst can be prepared using the following synthetic route: [ka]

[0018] Step c) can be carried out by solvent extraction, for example by addition of diethyl ether. In such an embodiment, the catalyst dissolves in the organic phase and the polymer dissolves in the aqueous phase.

[0019] Furthermore, the method comprises: a') adding a surfactant to the reaction solution It may further include:

[0020] Step a') can be carried out during or immediately after step a), in other words, the surfactant can be added to the reaction solution simultaneously with the monomer, the catalyst, and optionally the base, or can be added after the polymerization and purification process.

[0021] As can be seen from the above, the surfactant is not essential for the method according to the first embodiment. However, if the polymer is to be used for spin casting and if the catalyst contains a carboxyl substituent, the surfactant must be added. However, if the catalyst contains a sulfonyl substituent, spin casting may be performed without the addition of a surfactant. Furthermore, the surfactant may be added to improve electrical properties by modifying the thin film morphology and surface roughness.

[0022] The surfactant may be selected from polyethylene glycol (PEG), polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), sodium polystyrene sulfonate (PSSNa), polystyrene sulfonic acid (PSSH), sodium dodecylbenzene sulfonate (DBSNa), polyquaternium-4 (PQ-4), polyquaternium-10 (PQ-10), polydiallyldimethylammonium chloride (PDADMAC), polydiallyldiethylammonium chloride (PDADEAC), TWEEN® 20, TWEEN® 80, κ-carrageenan, PEG-PPG-PEG, polyoxyethylene (10) tridecyl ether, Triton™ X-100, or a combination thereof. [ka]

[0023] According to the present invention, the solvent system may comprise a polar aprotic solvent. In such embodiments, the method may further comprise: d) performing a solvent exchange to remove the polar aprotic solvent and further comprising:

[0024] The polar aprotic solvent may be dimethyl sulfoxide (DMSO), dimethylformamide (DMF), dimethylacetamide (DMA), or a combination thereof. The ratio of water to the polar aprotic solvent is 10:90 to 90:10, preferably 40:60 to 60:40.

[0025] When the solvent system comprises a polar aprotic solvent, the catalyst may be a quinone oxidizer selected from tetramethylbenzoquinone (TMQ), alkyl-, sulfonyl-, and carboxyl-substituted benzoquinones (AQ), or combinations thereof.

[0026] The polymerization step (ie, step b) may proceed at a temperature of from 20°C to 150°C.

[0027] As mentioned above, the method of the present invention comprises: c') removing the catalyst by extraction and / or oxidation to recycle the catalyst. It may further include:

[0028] The method of the present invention may also include additional steps, such as work-up and purification steps, which may be carried out in water.

[0029] The present invention further relates to a water-processable n-type conductive polymer comprising a conventional conjugated structure having a centrosymmetric benzene ring fused to two rings, preferably five-membered rings, wherein the fused ring preferably comprises a heteroatom such as O, N, or S. The water-processable n-type conductive polymer further comprises a segment having a benzene ring comprising at least one substituent having a relatively electronegative element (e.g., O, N, or S) bonded to carbon by a single bond, each substituent having an acidic hydrogen. In particular, the water-processable n-type conductive polymer can be poly[(2,2'-(2,5-dihydroxy-1,4-phenylene)diacetic acid)-co-3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione] (PDADF), poly[(2,2'-(2,5-dihydroxy-1,4-phenylene)diacetic acid) (PDADF-P), or a mixture thereof.

[0030] The polymer according to the present invention can be obtained by the above method.

[0031] The present invention also relates to a water-based n-type conductive ink comprising the water-processable n-type conductive polymer described above.

[0032] Therefore, the n-type conductive ink of the present invention can be spin-coated or drop-cast in air at room temperature to form a film with a thickness of 1 nm to 1 cm, more preferably 10 nm to 10 μm, which may exhibit an electrical conductivity of approximately 60 S / cm.

[0033] The present invention further relates to an organic optical or electronic device comprising the above n-type conductive polymer.

[0034] As mentioned above, the n-type water-based conductive ink according to the present invention can be used in organic optical or electronic devices such as OECTs, thermoelectric devices, ternary logic inverters, OPVs, OLEDs, organic supercapacitors, batteries, fuel cells, sensors, and memories.

[0035] Embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which: [Brief explanation of the drawings]

[0036] [Figure 1] Figure 1 shows a schematic diagram of the synthesis of PBFDO and PDADF over the designed catalyst TMQ-PA. [Figure 2] 1 illustrates a polymer of the present invention. [Figure 3] (a) Synthesis route of the new catalyst TMQ-PA, (b) possible reaction routes for PDADF polymerization and catalyst recycling, and (c) 1H NMR spectrum of the recycled catalyst. [Figure 4] Figure 1 shows spectroscopic characterization of PBFDO synthesized from TMQ and TMQ-PA: (a) UV-vis spectra of PBFDO and PDADF (50 weight percent (wt%) TW80), and (b) FTIR spectra of PBFDO synthesized from TMQ and TMQ-PA. [Figure 5-1] Figure 1 shows FTIR and XPS spectral analyses of PBFDO and PDADF: (a) Comparison of FTIR spectra of PBFDO and PDADF, offset; (b) Comparison of FTIR spectra of PDADF and sodium (Na)-substituted HPDA, offset; and XPS spectra of PBFDO (c, e) and PDADF (d, f). [Figure 5-2] Figure 1 shows FTIR and XPS spectral analyses of PBFDO and PDADF: (a) Comparison of FTIR spectra of PBFDO and PDADF, offset; (b) Comparison of FTIR spectra of PDADF and sodium (Na)-substituted HPDA, offset; and XPS spectra of PBFDO (c, e) and PDADF (d, f). [Figure 5-3] Figure 1 shows FTIR and XPS spectral analyses of PBFDO and PDADF: (a) Comparison of FTIR spectra of PBFDO and PDADF, offset; (b) Comparison of FTIR spectra of PDADF and sodium (Na)-substituted HPDA, offset; and XPS spectra of PBFDO (c, e) and PDADF (d, f). [Figure 6] Figure 1 shows FTIR spectra. (a) One equivalent of sodium hydroxide (NaOH) was added to an aqueous dispersion of HBFDO to form HPDA-Na, which has a fully ring-opened structure. (b) Different mass ratios of HPDA were added to a 5 mg / mL PBFDO DMSO ink, stirred overnight, and then cast into a film. FTIR spectra were measured. [Figure 7] Figure 1 shows X-ray absorption spectroscopy (XAS) probing the transitions from the C- and O-core levels to unoccupied states of PDADF and PBFDO. [Figure 8-1] Electrical properties and characteristics of TEGs composed of PDADF n-legs and PEDOT:PSS p-legs. (a) Electrical conductivity. (b) Comparison of n-CP conductivity with different treatment solvents. [Figure 8-2]Electrical properties and characteristics of a TEG composed of a PDADF n-leg and a PEDOT:PSS p-leg. (c) Normalized PDADF (50 weight percent (wt%) TW80) thin film conductivity as a function of time during storage at room temperature. (d) Output voltage and power of the TEG at different temperature differentials. [Figure 8-3] Electrical properties and characteristics of a TEG composed of PDADF n-legs and PEDOT:PSS p-legs. (e) Variation with open-circuit voltage and short-circuit current. (f) Output of a TEG with gold contacts under different temperature gradients. [Figure 9] Figure 1 shows atomic force microscopy (AFM) height images of the microstructures of PBFDO synthesized from different catalysts from TMQ and TMQ-PA: AFM height images of PDADF and PDADF (50 wt % TW80) synthesized from water. [Figure 10] Figure 2 shows 2D grazing incidence wide-angle X-ray scattering (GIWAXS) patterns of PBFDO (a, b) and PDADF (c, d). [Figure 11] Figure 1 shows (a) in-plane and (b) out-of-plane GIWAXS line cuts of PBFDO (with TMQ or TMQ-PA), PDADF, and PDADF (50 wt% TW80) films. Table 1 summarizes the π-π stacking and lamellar distances calculated from the GIWAXS 1D data, as well as the FWHM of the (010) and (100) peaks. [Figure 12-1] Figure 1 shows the Seebeck coefficient measurements of PBFDO, PDADF, and PDADF (50 wt% TW80), where negative values ​​indicate the n-type character of these polymers. [Figure 12-2] Figure 1 shows the Seebeck coefficient measurements of PBFDO, PDADF, and PDADF (50 wt% TW80), where negative values ​​indicate the n-type character of these polymers. [Figure 13-1] FIG. 1 shows the thermal stability of PDADF. [Figure 13-2] FIG. 1 shows the thermal stability of PDADF. [Figure 13-3]FIG. 1 shows the thermal stability of PDADF. [Figure 14-1] FIG. 1 shows the thermal stability of PDADF. [Figure 14-2] FIG. 1 shows the thermal stability of PDADF. [Figure 15] FIG. 1 is a diagram showing the internal resistance of an OTEG according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0037] As mentioned above, the present invention provides a method for producing a water-processable n-type conducting polymer, comprising the steps of: a) adding a monomer to a solvent system comprising water in the presence of a catalyst and a base to prepare a reaction solution; b) polymerizing the monomer in the reaction solution to obtain an n-type conductive polymer dispersion; c) post-treating the n-type conductive polymer dispersion to obtain a water-processable n-type conductive polymer; The present invention provides a method comprising:

[0038] Figure 2 illustrates the polymers described in this application. Thus, Figure 2a shows the synthesis of PBFDO from DMSO using TMQ as a catalyst according to the reported method. Attempts to directly polymerize HBFDO from water using duroquinone (TMQ) as the oxidant failed due to the low solubility of TMQ in water, resulting in a reddish-brown mixture and no polymerization (Figure 2b). To solve this problem, a carboxyl group was introduced into TMQ to increase its water solubility using the synthetic method shown in Figure 3a. TMQ-PA (3-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dien-1-yl)propanoic acid) was synthesized in two steps with an overall yield of 48%.

[0039] The synthesis of PBFDO from DMSO using TMQ-PA as a catalyst demonstrates its ability to promote polymerization and in situ doping (Figure 2c). However, when water was used instead of DMSO under the same conditions as in (c), no polymer was detected (Figure 2d). As shown in Figure 2e, PDADF could be obtained from aqueous polymerization using 1 equivalent of sodium hydroxide (NaOH). Adding Tween 80 (TW80) as a surfactant to the final PDADF aqueous ink resulted in the formation of PDADF (50 wt% TW80), as shown in Figure 2f.

[0040] PBFDO was synthesized in DMSO according to the procedure outlined by Tang and coworkers as previously described, and the catalytic efficiency of TMQ-PA for the oxidation of HBFDO was examined and compared with that of TMQ (Figure 2c). Fourier transform infrared (FTIR) spectra of PBFDO produced by TMQ-PA and TMQ showed a peak at 1781 cm. -1 They show identical absorption characteristics, including an indistinguishable fingerprint region (Figure 4b) along with the characteristic carbonyl peak of . However, attempts to synthesize PBFDO by reacting TMQ-PA with HBFDO in water failed because the solubility of TMQ-PA in water was still limited (Figure 2d). This problem was resolved by introducing one equivalent of sodium hydroxide (NaOH), which produced water-soluble sodium 3-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dien-1-yl)propanoate (TMQ-PANa), and TMQ-PA was completely dissolved in water. Addition of one equivalent of HBFDO to an aqueous TMQ-PANa solution resulted in the formation of a partially ring-opened PBFDO copolymer structure, PDADF, as shown in Figures 1 and 3b. In particular, upon reaction with HBFDO, TMQ-PANa precipitates as the water-insoluble 6-hydroxy-5,7,8-trimethylchroman-2-one (HTMCO), which can be recovered by solvent extraction using a mixture of water and diethyl ether. The extracted compound was analyzed by proton nuclear magnetic resonance ( 1H NMR revealed a TMQ-PA:HTMCO ratio of approximately 1:1.4 (Figure 3c). HTMCO can be reoxidized to TMQ-PA using the same synthetic procedure as in Figure 3a, resulting in a purity of over 99% and a recovery of 74% of the initial oxidant.

[0041] The chemical structure of PDADF and its differences from PBFDO were investigated. The FTIR spectrum of PDADF shows several distinct features compared to PBFDO (Fig. 5a). The latter has a peak at 1781 cm -1 While PDADF shows a pronounced C=O stretching of the lactone moiety at 1850–1776 cm, it lacks a clear peak in the same region. -1 , 1752~1624cm -1 , and 1623~1471cm -1 Three broad features are observed within the range of 1752-1624 cm -1 The features in the highlighted region are attributed to the characteristic bands of carboxylic acid groups. These features are qualitatively similar to those observed in the FTIR spectrum of HBFDO monomer treated with one equivalent of sodium hydroxide (NaOH). One equivalent of sodium hydroxide (NaOH) is known to be unstable in aqueous alkaline environments, leading to ring-opening and the formation of sodium 2-(4-(carboxymethyl)-2,5-dihydroxyphenyl)acetate (HPDA-Na). This observation is also consistent with the decrease in pH measured before (11.59) and after (4.98) polymerization. Addition of one equivalent of sodium hydroxide (NaOH) to an aqueous dispersion of PBFDO polymerized with TMQ in DMSO revealed FTIR absorption characteristics similar to those of PDADF, confirming the presence of at least a partially ring-opened structure in PDADF (Figure 5a).

[0042] In an attempt to further understand the FTIR spectrum of PDADF, we compared PDADF with 2,2′-(2,5-dihydroxy-1,4-phenylene)diacetic acid (HPDA) and its sodium (Na)-substituted derivatives (HPDA-Na and HPDA-2Na, Figure 5 b). 1H NMR analysis revealed that the sodium (Na) substitution of HPDA made minimal difference. The FTIR spectrum of HPDA-Na exhibited a peak at approximately 1621–1542 cm -1 This shows the generation of a new asymmetric COO- vibration [vas(COO-)], which becomes more prominent as the deprotonation of the carboxylic acid in HPDA-2Na progresses. This vas(COO-) peak appears in the pink region (1545–1462 cm) corresponding to the C=C stretching. -1 ), coupled with the broadened peak of PDADF (1621-1462 cm -1 ), which is the basis for the features observed in the PDADF derivatives. Compared to the HPDA derivatives, the broader C=C stretch of PDADF is expected to be due to the formation of new C=C bonds between methylene groups during polymerization. The C=C bond vibration absorption of PBFDO is similarly broad (Figure 5a, approximately 1450 cm). -1 Furthermore, the characteristic band of the carboxylic acid group (1752–1624 cm -1 ) gradually shifts and decreases in intensity as sodium (Na) substitution of HPDA increases, explaining the broad features exhibited by PDADF in this region.

[0043] To further explore the structural differences of PDADF relative to PBFDO and the absence of a distinct lactone C=O peak in the FTIR spectrum of PDADF, PBFDO was mixed with various mass ratios of HPDA. When a large amount of HPDA was added, the peak at 1781 cm -1 The peak position of the C=O vibration in the doped PBFDO was observed to shift (Fig. 6b). + COO-(H + This corresponds to the strengthening of the C=O vibrations hypothesized to occur upon contact with the COO-(H) / OH groups. This change is relatively small due to the difficulty in incorporating HPDA into PBFDO, as evidenced by the white crystals observed after the film dried. However, in films of the partially ring-opened polymer, the C=O groups of the lactone are converted to COO-(H) / OH groups. +) / OH groups, the lactone C=O vibrations are expected to be broadened and significantly shifted. Based on these results, the lactone C=O vibrations of PDADF are broadened and shifted to higher wavenumbers compared to PBFDO, resulting in a peak at approximately 1800 cm. -1 It is assumed that absorption is observed at (Fig. 5a).

[0044] To further characterize the chemical structure of PDADF, X-ray photoelectron spectroscopy (XPS) was performed. The XPS O(1s) spectrum of PDADF showed the presence of PBFDO (C=O at 531.7 eV, C=O at 533.4 eV, C=O at 535.1 eV, and C=OH at 535.1 eV). + In contrast to PBFDO, an additional peak at 533.2 eV (OH on phenol) can be fitted. This observation indicates that PDADF has a more complex chemical structure (Figure 5c, Figure 5d). As a result, the C=O peak of PDADF is broader and has a larger area compared to PBFDO, suggesting the complex presence of C=O from both the open carboxylic acid moiety and the closed lactone moiety (Figure 5d). The C=O-H peak corresponds to the doping state of the protons bonded to the C=O group. + Peaks can be seen in both the PDADF and PBFDO polymers.

[0045] Regarding the C(1s) spectra, PDADF and PBFDO exhibit similar fitting peaks due to their similar carbon chemical environments, except for the different binding energies of the CO peaks. This observation is consistent with the O(1s) spectrum of PDADF, which shows the presence of C-OH and CO-C peaks (Figures 5e and 5f). In summary, XPS confirmed that the PDADF backbone comprises both closed and open ring structures.

[0046] To further explore the electronic properties of PDADF, we used X-ray absorption spectroscopy (XAS) to investigate the transitions from the C and O core levels of PDADF to unoccupied states. Figure 7 shows the C and O K-edge XAS spectra of PDADF compared to PBFDO. It is clear that the spectral characteristics of PDADF are highly consistent with those of PBFDO. Particularly noteworthy is the similarity of the O K-edge features, which are very similar to those of PBFDO (Figure 7a). This consistency is attributed to the occurrence of self-doping in the O-related molecular structure of PBFDO, as previously reported. Instead, a slight difference is observed in the C K-edge spectrum (Figure 7b), where the first absorption of PBFDO corresponds only to the shoulder structure, indicating a change in the C-related molecular structure of PDADF, which is attributed to the ring-opening moiety. Furthermore, a slight increase in the absorption energy of PDADF compared to PBFDO was also observed. Assuming that the exciton binding energies of PDADF and PBFDO are the same, this increase suggests a slight decrease in the lowest unoccupied molecular orbital (LUMO) energy level of PDADF. The corresponding electron affinity (EA) of PDADF is approximately 0.1 eV lower than that of PBFDO. Generally, the similar absorption characteristics observed for PDADF and PBFDO indicate that the electronic properties of both polymers are similar.

[0047] Based on the aforementioned FTIR, XPS, and XAS data, we propose that the PDADF structure contains both closed and open ring moieties, similar to those of PBFDO. In the latter, the lactone moiety opens to form carboxylic acid and phenolic groups, facilitating polymer dispersion in water. However, due to limitations in polymer characterization, quantifying the ratio between these structures is difficult.

[0048] Next, the electrical and thermoelectric properties of PDADF were investigated and compared with those of PBFDO (Figure 8a). The electrical conductivity of PBFDO films processed from DMSO and measured by the four-point probe method was approximately 1379 ± 83 S cm for TMQ. -1, and approximately 1297±98 S cm for TMQ-PA. -1 This result confirms the catalytic efficiency of TMQ-PA for the oxidation of HBFDO in DMSO. In contrast, the PDADF film drop-cast from water exhibited a catalytic activity of 30.9 ± 4.6 S cm. -1 The lower electrical conductivity of PDADF relative to PBFDO is likely due to the coarser morphology of the former compared to the latter (see Figure 9). Using Tween 80 (TW80) as a surfactant resulted in a more homogeneous film (Figure 9), with an electrical conductivity of 66 S cm. -1 (Average 48±18S cm -1 , see Table 2). While these values ​​are lower than those measured for PBFDO in DMSO, they are the highest reported for n-type conducting polymers synthesized and processed from water or water / alcohol mixtures (Figure 8b), and are also the highest among n-type conducting polymers processed entirely at room temperature. Remarkably, the electrical conductivity of PDADF synthesized using recycled TMQ-PA is comparable to that of PDADF produced using freshly synthesized oxidants (Table 2, entry 4), highlighting the robustness and effectiveness of the recycling process.

[0049] [Table 1]

[0050] Grazing incidence wide-angle X-ray scattering (GIWAXS) revealed that PBFDO and PDADF films exhibited similar edge-on stacking orientation on the substrate, with PDADF exhibiting a weaker π-π stacking (010) signal compared to PBFDO (Figures 10 and 11). PDADF exhibited q z =0.657Å -1(d-spacing = 9.53 Å), showing lamellar packing, and the addition of TW80 increases the d-spacing to 13.46 Å (Figure 11b). Furthermore, both PDADF and PDADF (50 wt% TW80) exhibit less crystalline π-π stacking, a reduced coherence length, and increased quasicrystalline disorder both in-plane and out-of-plane compared to PBFDO (Table 1).

[0051] The Seebeck coefficient of PDADF is -12.25±1.16μV K -1 When TW80 was used as the surfactant, this value was −10.52 ± 1.02 μV K -1 For comparison, the Seebeck coefficient of the PBFDO film is approximately -20 μV K -1 , which is consistent with previous reports. The negative sign of the Seebeck coefficient value is consistent with electrons being the majority charge carriers.

[0052] Typically, n-type conductive polymers are prone to degradation when processed and manipulated in air. This degradation is primarily due to the quenching of radical anions by atmospheric moisture and oxygen. The air stability of PDADF films was studied by monitoring the change in electrical conductivity over time and under ambient conditions. Thin films of PDADF (71 ± 9 nm thick, 50 wt% TW80) showed excellent electrical conductivity retention of 90% even after 146 days (Figure 8c). This result is particularly noteworthy for an n-type conjugated polymer synthesized and processed entirely from water. Furthermore, PDADF exhibited excellent thermal stability, with no phase transitions observed (Figures 13 and 14).

[0053] Next, we evaluated the feasibility of fabricating the first all-polymer, water-processable, flexible organic thermoelectric generator (OTEG). An aqueous dispersion of PDADF (50 wt. % TW80) was used to fabricate the n-type leg, and PEDOT:PSS (5 wt. % EG) was used for the p-type leg. Polyethylene naphthalate (PEN) foil (100 μm thick) was used as the flexible substrate, and gold electrodes were patterned by evaporation through a shadow mask. Subsequently, PDADF and PEDOT:PSS were drop-cast through the mask. Importantly, all processes and measurements were performed in air without sealing. These flexible OTEGs processed from water exhibited an internal resistance of 78 Ω (Figure 15), open-circuit voltage and short-circuit current responses proportional to the applied temperature gradient, and a notable thermovoltage of 42.6 μV K. -1 (Figure 8e). The power output per pn pair of the TEG exhibits a temperature gradient and quadratic relationship, ranging from 0.25 nW (△T = 10 K) to 14.7 nW (△T = 50 K).

[0054] According to a specific embodiment of the present invention, the catalyst can be synthesized as follows: Methanesulfonic acid (10 mL) was heated to 70°C in an oil bath, and 2,3,5-trimethylbenzene-1,4-diol (1 g, 6.57 mmol) and tert-butyl acrylate (1.09 mL, 7.42 mmol) were added with stirring. The reaction was continued at 70°C for 90 minutes, after which the mixture was diluted with 100 mL of water and extracted three times with ethyl acetate. The extract was washed with water, saturated sodium bicarbonate (NaHCO), saturated sodium chloride (NaCl), and dried (sodium sulfate (NaSO)). The solvent was removed using a rotary evaporator. The residue was purified by silica gel chromatography to obtain the pure solid lactone HTMCO (0.81 g, 60% yield). To 90 mL of 10% aqueous acetonitrile containing the lactone 6-hydroxy-5,7,8-trimethylchroman-2-one (HTMCO) (1.8 g, 8.73 mmol) was added dropwise a solution of NBS (1.63 g, 9.16 mmol) in 18 mL of acetonitrile. The reaction mixture was stirred at 25 °C for 1 h, and the solvent was removed using a rotary evaporator. The residue was diluted with water and extracted several times with ether. The combined ether extracts were washed with water and brine and dried using sodium sulfate (NaSO). The solvent was removed, and the product was crystallized (acetone-hexane) to give 1.5 g of TMQ-PA (80% yield). [ka]

[0055] The PDADF aqueous ink was synthesized as follows: TMQ-PA (7.89 mmol, 1.75 g, 1 equiv.) was added to a 250 mL round-bottom flask equipped with a stir bar, followed by freshly prepared 0.5 M sodium hydroxide (NaOH) (7.89 mmol, 15.8 mL, 1 equiv.) and stirred at room temperature (RT) for 10 min until all TMQ-PA was dissolved. An additional 42.5 mL of DI water was added to the solution to form a 30 mg / mL dispersion according to the monomer HBFDO. HBFDO (7.89 mmol, 1.50 g, 1 equiv.) was added to the diluted solution and stirred at 100 °C for 3.5 h. The final suspension was cooled to room temperature, diluted with water, and extracted five times with diethyl ether until the organic phase became colorless. All diethyl ether was recovered and purified by column chromatography to obtain a recycled mixture of the catalyst and its precursor, which was then oxidized to produce TMQ-PA. The PDADF aqueous phase was collected by centrifugation (6000 rpm, 10 min) and washed five more times with DI water. The PDADF was collected from the bottom of the centrifuge tube to form an approximately 20 mg / mL aqueous dispersion for drop casting and other thin film processing methods.

[0056] PDADF (50 wt% TW80) was synthesized as follows: PDADF was synthesized based on the same method as above, and then 0.75 g of TW80 (0.5 times the mass according to HBFDO) was added. The mixture was stirred for another 2 days to finally form a PDADF (50 wt% TW80) aqueous ink.

[0057] Thus, the method of the present invention unexpectedly succeeded in producing a doped poly(2,2'-(2,5-dihydroxy-1,4-phenylene)diacetic acid) (PDADF) aqueous ink (Figure 2e). The resulting PDADF exhibited excellent electrical conductivity, 30.9 S cm. -1 Furthermore, when the surfactant TW80 was added to the PDADF water-based ink to form PDADF (50 wt% TW80), the conductivity of the drop-cast film reached a maximum of 66 S cm. -1 (Average 48±18S cm -1) and surprisingly, the spin-cast film exhibits a peak temperature of 16 S cm -1 The PDADF film maintained its conductivity at 90% even after 147 days in ambient air without encapsulation, demonstrating state-of-the-art air stability. Furthermore, the catalyst TMQ-PA exhibited excellent recyclability, achieving a 74% recovery rate during aqueous polymerization. PDADF films maintained the same high conductivity using recycled catalysts. Furthermore, TMQ-PA has proven versatile and efficient in PBFDO polymerization, achieving comparable performance. To demonstrate the practicality of PDADF, we demonstrated its application as the n-type component of a thermoelectric generator (TEG), achieving a maximum output power of 14.7 nW at a temperature difference (△T) of 50 K, equivalent to one pn pair. The water-based n-type PDADF ink is expected to be utilized in a wide range of applications due to its water-processability, cost-effectiveness, recyclable catalyst, and excellent electrical conductivity. This ink is particularly promising for complementary hole- and electron-based devices, such as TEGs and bioelectronic devices.

[0058] While the present invention has been described with reference to various embodiments, those skilled in the art will recognize that modifications may be made without departing from the scope of the invention. The detailed description is to be considered as exemplary, and it is the appended claims, including all equivalents, that are intended to define the scope of the invention.

[0059] [Table 2]

Claims

1. 1. A method for producing a water-processable n-type conducting polymer, comprising: a) preparing a reaction solution by adding a monomer to a solvent system comprising water in the presence of a catalyst and a base; b) polymerizing the monomer in the reaction solution to obtain an n-type conductive polymer; c) post-treating the n-type conductive polymer dispersion to obtain a water-processable n-type conductive polymer; The method comprising:

2. 2. The method of claim 1, wherein the catalyst is selected from sulfonyl-substituted benzoquinones and carboxyl-substituted benzoquinones.

3. The catalyst is selected from the group consisting of: 【Chemistry 1】 (In the formula, R ０ , R １ , and R ３ are independently H, Me, or —CH ２ R ４ R ５ COOH, R ４ and R ５ are independently H or Me; R ２ is -COOH or -SO ２ OH) 3. The method of claim 1 or 2, selected from the group consisting of:

4. The catalyst is 3-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dien-1-yl)propanoic acid (TMQ-PA, R ０ =R １ =R ３ = Me, R ４ =R ５ = H, R ２ =-COOH), 3,3'-(4,5-dimethyl-3,6-dioxocyclohexa-1,4-diene-1,2-diyl)dipropionic acid (AAMMQ, R ０ =R １ = Me, R ３ =-CH ２ R ４ R ５ COOH, R ４ , R ５ = H or Me, R ２ =-COOH), 3,3'-(2,5-dimethyl-3,6-dioxocyclohexa-1,4-diene-1,4-diyl)dipropionic acid (AMAMQ, R １ =R ３ = Me, R ０ =-CH ２ R ４ R ５ COOH, R ４ , R ５ = H or Me, R ２ 4. The method of claim 1, wherein the aryl group is selected from the group consisting of aryl, ...

5. The base is MOH, and M is Li ＋ , Na ＋ , K. ＋ , Me ４ N ＋ , Bu ４ N ＋ The method of any one of claims 1 to 4, wherein the compound is selected from the group consisting of:

6. The method comprises: a') adding a surfactant to the water-processable n-type conductive polymer The method of any one of claims 1 to 5, further comprising:

7. the solvent system further comprising a polar aprotic solvent, the method comprising: d) performing a solvent exchange to remove the polar aprotic solvent The method of any one of claims 1 to 6, further comprising:

8. 8. The method of claim 7, wherein the polar aprotic solvent is dimethyl sulfoxide (DMSO), dimethylformamide (DMF), dimethylacetamide (DMA), or a combination thereof.

9. 9. The method according to claim 7 or 8, wherein the ratio of water to the polar aprotic solvent is from 5:95 to 95:

5.

10. The method according to any one of claims 7 to 9, wherein a surfactant is added during step d).

11. The method according to any one of claims 1 to 10, wherein step b) is carried out at a temperature of from 20°C to 150°C.

12. 12. The method of any one of claims 1 to 11, wherein the monomer is 3,7-dihydrobenzo[1,2-b:4,5-b]difuran-2,6-dione (HBFDO), and the n-type conductive polymer is poly[(2,2'-(2,5-dihydroxy-1,4-phenylene)diacetic acid)-co-3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione] (PDADF), poly[(2,2'-(2,5-dihydroxy-1,4-phenylene)diacetic acid) (PDADF-P), or a mixture thereof.

13. The method comprises: c') removing the catalyst by extraction and oxidation to recycle the catalyst. The method of any one of claims 1 to 12, further comprising:

14. 1. A water-processable n-type conductive polymer comprising a normal conjugated structure having a centrosymmetric benzene ring fused with two rings, wherein the water-processable n-type conductive polymer further comprises a segment having a benzene ring comprising at least one substituent having a relatively electronegative element attached to a carbon by a single bond, wherein each substituent has an acidic hydrogen.

15. 15. The water-processable n-type conducting polymer of claim 14, wherein the n-type conducting polymer is poly[(2,2'-(2,5-dihydroxy-1,4-phenylene)diacetic acid)-co-3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione] (PDADF), poly[(2,2'-(2,5-dihydroxy-1,4-phenylene)diacetic acid) (PDADF-P), or a mixture thereof.

16. A water-based ink comprising the water-processable n-type conductive polymer of claim 14 or 15.

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