Polymer capacitors comprising solution-processed n-type conducting polymers

Abstract

The present invention relates to a polymer capacitor comprising an anode, a dielectric layer, and a cathode, wherein the cathode comprises a solution-processed n-type conducting polymer having a conductivity of at least 100 S / cm, preferably at least 500 S / cm.

Description

[Technical Field]

[0001] The present invention relates to polymer capacitors comprising solution-processed n-type conducting polymers and to methods for making water-based n-type conducting polymers for use in such devices. [Background technology]

[0002] Water-based conductive polymer 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 However, when considering complementary components for semiconductor devices and circuits, water-based n-type (electron transporting) conducting polymers become important.

[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, Fei Huang et al. reported a solution-processed n-type conductive polymer poly(benzodifurandione) (PBFDO) with an electrical conductivity exceeding 2000 S / cm (Nature, 2022, s41586-022-05295-8).

[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 cost-effective printed organic electronics.

[0006] Polymer capacitors are electrolytic capacitors (e-caps) with a solid conductive polymer electrolyte. There are four types: polymer tantalum electrolytic capacitors (polymer Ta-e-cap), polymer aluminum electrolytic capacitors (polymer Al-e-cap), hybrid polymer capacitors (hybrid polymer Al-e-cap), and polymer niobium oxide electrolytic capacitors.

[0007] Polymer Ta-e-cap is available in a rectangular surface mount device (SMD) chip style. Polymer Al-e-cap and hybrid polymer Al-e-cap are available in a rectangular surface mount device (SMD) chip style, a cylindrical SMD (V-chip) style, or as a radial leaded version (single ended).

[0008] Polymer capacitors are characterized by particularly low internal equivalent series resistance (ESR) and high ripple current ratings. These electrical parameters are similar to those of solid tantalum capacitors in terms of temperature dependence, reliability, and service life, but they have much better temperature dependence and a significantly longer service life than aluminum electrolytic capacitors with non-solid electrolytes. Polymer e-caps typically have higher leakage current ratings than other solid or non-solid electrolytic capacitors.

[0009] Polymer capacitors are also available in hybrid constructions. Hybrid polymer aluminum electrolytic capacitors combine a solid polymer electrolyte with a liquid electrolyte. These types are characterized by low ESR values, low leakage current, and immunity to transients. However, like non-solid e-caps, they have a temperature-dependent service life.

[0010] Polymer capacitors are primarily used in power supplies for integrated electronic circuits as buffer, bypass and decoupling capacitors in devices with flat or compact designs. They therefore compete with multilayer ceramic capacitors (MLCCs), but offer higher capacitance values ​​and are free from microphonic effects (such as class 2 and class 3 ceramic capacitors).

[0011] The most important electrical property of the electrolyte in an electrolytic capacitor is its electrical conductivity. The electrolyte forms the counter electrode, or cathode, of the electrolytic capacitor (e-cap). The advantage of a solid polymer electrolyte is that the capacitor has a significantly lower ESR and a lower temperature dependence of the electrical parameters.

[0012] Currently available polymer electrolytes are made from precursors consisting of very small base materials that can penetrate even the smallest pores. The size of these precursors limits the size of the pores in etched aluminum anode foils or the size of tantalum powder. The polymerization rate must be controlled during capacitor fabrication. Polymerization that is too fast results in incomplete coverage of the anode, while polymerization that is too slow increases production costs. Neither the precursor nor the polymer or its residues can chemically or mechanically attack the anodic oxide. Polymer electrolytes must be highly stable over long periods of time and across a wide temperature range. Currently available polymer e-caps employ either polypyrrole (PPy) or polythiophene (PEDOT). However, capacitors containing these polymers suffer from poor thermal stability. The daily operating temperatures of supercapacitors used in applications such as autonomous driving can exceed 170°C. Conventional conductive polymers, even with air-free encapsulation, lose their conductivity at these temperatures.

[0013] Therefore, there is a need for a polymer capacitor comprising a solution-processed, preferably water-based, n-type CP ink with high conductivity, processability, and stability. Summary of the Invention

[0014] In view of the above, the present invention aims to solve the problems of the prior art. To this end, the present invention relates to a polymer capacitor comprising an anode, a dielectric layer, and a cathode, wherein the cathode comprises a solution-processed n-type conducting polymer having a conductivity of at least 100 S / cm, preferably at least 500 S / cm.

[0015] The solution-processed n-type conductive polymer may further have a work function of at least 4.7 eV, preferably at least 4.9 eV. Furthermore, the solution-processed n-type conductive polymer may be free of side chains. In the present invention, the term "free of side chains" refers to a polymer with only one carbon atom extending from its conjugated backbone. This embodiment offers the advantage of improving the interface of the active material with the nanoparticles and / or electron collector surface, since the side chains provide some distance between the π-system of the polymer and the surface of the electron collector, thereby reducing charge transfer. Furthermore, the solution-processed n-type conductive polymer may comprise a repeating unit comprising a centrosymmetric benzene ring as the backbone, an active hydrogen, and at least one electron-withdrawing group at the benzylic position. In particular, the solution-processed n-type conductive polymer can be poly(benzodifurandione) (PBFDO), 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, as shown below. The structure of PDADF-P is similar to that of PDADF, but lacks the heterocyclic segment. [ka]

[0016] The n-type conductive polymer used in the polymer capacitor of the present invention is 1) adding a monomer to a solvent system comprising a polar aprotic solvent and an oxidizing agent in the presence of a catalyst to obtain a reaction solution; 2) polymerizing the monomer in the reaction solution to obtain an ink containing an n-type conductive polymer; It can be produced by a method comprising:

[0017] The catalyst is a quinone or quinone precursor and comprises at least one branched side chain. The term "quinone precursor" refers to a species capable of forming a quinone structure. The side chain may comprise 3 to 100 carbon atoms. The side chain may further comprise at least one functional group, such as a hydroxyl group. Furthermore, the side chain may further comprise a branching center. Furthermore, the side chain may comprise at least one chiral center. It has been demonstrated that the catalyst produced by this method does not crystallize during the polymerization reaction because the at least one branched side chain prevents such crystallization. Because the catalyst does not crystallize, it does not need to be removed from the ink, eliminating the need for a dialysis step, as described in WO 2022 / 262159.

[0018] Thus, one advantage of the above method is that the catalyst does not crystallize due to the presence of at least one branched side chain, eliminating the need for a dialysis step to remove the catalyst. Branched side chains that are sufficiently long will not crystallize, while branched side chains with 3-4 carbon atoms will crystallize.

[0019] 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]

[0020] 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]

[0021] 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 is polybenzodifurandione (PBFDO).

[0022] According to certain embodiments, the catalyst may be vitamin E. As is well known in the art, vitamin E is a group of eight fat-soluble compounds that includes four tocopherols and four tocotrienols, as shown below. [ka]

[0023] It should be noted that according to the above method, the term vitamin E refers to at least one of the above species. In other words, each of the above species may be present in the reaction solution in pure form, or at least two of the above species may be present in any combination. Therefore, vitamin E can be selected from the group consisting of α-tocopherol, β-tocopherol, γ-tocopherol, δ-tocopherol, α-tocotrienol, β-tocotrienol, γ-tocotrienol, δ-tocotrienol, and mixtures thereof.

[0024] Vitamin E (a collective term for tocopherols and tocotrienols) is a natural product with high redox activity. Vitamin E is synthesized in photosynthetic plants and can be extracted in large quantities from them. All vitamin E molecules have long, branched hydrocarbon side chains and are naturally oily substances that do not crystallize at room temperature. According to the above method, inks containing n-type conductive polymers can be synthesized in one step or one pot using vitamin E as a catalyst, without the need for post-treatments such as dialysis and solvent removal. Compared to the three-step method reported by Fei Huang, the above method is significantly simpler.

[0025] Surprisingly, it has been found that vitamin E itself does not have catalytic activity, but its oxidized form does. In the presence of an oxidizing agent, vitamin E forms a benzoquinone derivative. According to the above method, the polymerization reaction is initiated by in-situ oxidation. Therefore, compared to methods known in the art, the above method offers the advantage of being a simplified and cost-effective method for producing inks comprising n-type conductive polymers. The major advantages of using vitamin E as a catalyst are its availability, low cost, and non-toxicity.

[0026] In certain embodiments, the polar aprotic solvent is DMSO and the oxidizing agent is hydrogen bromide (HBr), which is volatile and does not affect film formation when the ink is printed.

[0027] Alternatively, the oxidizing agent is an ionic liquid comprising a cation and an anion. In such embodiments, the method comprises: 3) Electrolyzing the reaction solution and Step 3) is carried out simultaneously with or after step 1).

[0028] In particular, step 3) can be carried out using a nickel cathode and a carbon anode at a voltage in the range of 4 to 6 V for a period in the range of 10 to 60 minutes.

[0029] The cation in the ionic liquid can be selected from the group consisting of 1-ethyl-3-methylimidazolium (EMIM), 1-butyl-3-methylimidazolium (BMIM), 1-allyl-3-methylimidazolium (AMIM), 1-hexyl-3-methylimidazolium (HMIM), butylmethylpyrrolidinium (BMP), propylmethylpyrrolidinium (PMP), triethylsulfonium, and mixtures thereof. The structures of the cations are shown below. [ka]

[0030] According to the method, the anion is chloride (Cl - ), bromide (Br - ), iodide (I - ), acetic acid (OAc), tetrafluoroboric acid (BF4 - ), hexafluorophosphate (PF6 - ), bistrifluoromethanesulfonimide (TFSI), trifluoromethanesulfonic acid (OTf), dicyanamide (DCA), hydrogen sulfate (HSO4 - ), ethyl sulfate (ESO4 - ), thiocyanic acid (SCN), tosylic acid (OTs), mesylic acid (OMs), tetrachloroaluminic acid (AlCl4 -), diethyl phosphate (DEP), dimethyl phosphate (DMP), lactate (La), L-alanine anion (APP), and mixtures thereof. The structures of the above anions are shown below. [ka]

[0031] As mentioned above, the solvent system of the method comprises a polar aprotic solvent, which can be dimethyl sulfoxide (DMSO), dimethylformamide (DMF), dimethylacetamide (DMA), or a combination thereof.

[0032] The ratio of the oxidizing agent to the vitamin E is within the range of 0.1 to 100, preferably 0.25 to 5, and more preferably 1 to 3.

[0033] The polymerization reaction, ie step b) of the above process, can take place at a temperature between 20°C and 150°C.

[0034] The above method is 4) removing the catalyst by extraction and recycling the catalyst. may further comprise:

[0035] The extraction can be carried out using an alkane or an ether.

[0036] The overall outline of the above method is summarized as follows: [ka]

[0037] Therefore, inks containing n-type conductive polymers produced by the above method can be used to manufacture polymer capacitors of the present invention. The n-type conductive inks can be spin-coated or drop-cast in air at ambient temperature to form films with thicknesses of 1 nm to 1 cm, more preferably 10 nm to 10 μm. Such films may exhibit electrical conductivities of approximately 1000 S / cm.

[0038] The anode may be tantalum (Ta) in the form of a high purity sintered tantalum powder, with tantalum pentoxide (Ta2O5) as the dielectric.

[0039] Alternatively, the anode may be aluminum (Al) in the form of a high purity, electrochemically etched (roughened) aluminum foil with aluminum oxide (Al2O3) as the dielectric.

[0040] Alternatively, the anode may be niobium dioxide (NbO) using niobium pentoxide (Nb2O5) as the dielectric.

[0041] The polymer capacitors are in the form of rectangular SMD chips, usually molded in a plastic case, and may be available with sintered tantalum anodes or laminated aluminum anode foils.

[0042] Alternatively, the polymer capacitor may be in the form of a cylinder (Al only).

[0043] The polymer capacitor may be encapsulated with a resin, such as an epoxy resin, which prevents contact with air and improves the stability of the capacitor.

[0044] The present invention provides a method for making a polymer capacitor comprising an anode, a dielectric layer, and a cathode, wherein the cathode comprises a solution-processed n-type conducting polymer having a conductivity of at least 100 S / cm, preferably at least 500 S / cm, the method comprising: a) providing an anode and a dielectric layer; b) applying a cathode material onto the dielectric layer to provide a polymer capacitor; c) drying the polymer capacitor; Further reference is made to a method comprising:

[0045] The method according to the present invention comprises: a) sealing the polymer capacitor It may further include:

[0046] Step d) may be performed by applying an encapsulant, such as an epoxy, over the polymer capacitor and curing the polymer capacitor at a temperature of 100°C to 150°C for 1 hour to 24 hours. For example, the encapsulant may be cured overnight at 120°C. The curing temperature is preferably maintained at a level that avoids premature degradation of the polymer capacitor prior to capacitance testing.

[0047] The method according to the present invention comprises: a') anodizing the anode material to form the anode and dielectric layer may further comprise Step a') is performed before step a).

[0048] 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]

[0049] [Figure 1] 1 is a diagram showing a schematic cross-sectional structure of a polymer capacitor according to the present invention. [Figure 2] 1A-1C illustrate various embodiments of a polymer capacitor according to the present invention. [Figure 3] 3A and 3B are a perspective view and a cross-sectional view of the polymer capacitor shown in FIG. 2. [Figure 4] 3A and 3B are a perspective view and a cross-sectional view of the polymer capacitor shown in FIG. 2. [Figure 5] FIG. 1 shows the change in conductivity of a polymer electrode annealed at 200° C. in nitrogen. [Figure 6] FIG. 1 shows the change in conductivity of a polymer electrode in a resin-encapsulated capacitor after annealing at 200° C. in air. [Figure 7] FIG. 1 shows the change in conductivity of a polymer electrode annealed at 300° C. in nitrogen. [Figure 8] FIG. 1 shows the change in conductivity of a polymer ink stored in air. [Figure 9-1] FIG. 1 shows the thermal stability of solution-processed n-type conductive polymers used in polymer capacitors according to the present invention. [Figure 9-2] FIG. 1 shows the thermal stability of solution-processed n-type conductive polymers used in polymer capacitors according to the present invention. [Figure 10] FIG. 1 shows the capacitance retention of a polymer capacitor of the present invention compared with a reference capacitor. [Figure 11] FIG. 10 shows the thermal stability results in terms of capacitance of a capacitor according to the invention compared to a reference capacitor. [Figure 12] 1A and 1B show models of an ideal capacitor and a real capacitor. [Figure 13] FIG. 1 shows impedance spectroscopy comparing a polymer capacitor according to the present invention with a reference capacitor. DETAILED DESCRIPTION OF THE INVENTION

[0050] As discussed above, the present invention provides a polymer capacitor comprising an anode, a dielectric layer, and a cathode, wherein the cathode comprises a solution-processed n-type conducting polymer having a conductivity of at least 100 S / cm, preferably at least 500 S / cm.

[0051] In the embodiment shown in Figure 1, a schematic cross-sectional view of a polymer capacitor according to the present invention is shown. As can be seen, the polymer capacitor comprises an aluminum electrode (Al / Al2O3) comprising an aluminum (Al) foil and an oxide layer. The n-type conductive polymer is spin-coated onto the aluminum electrode. The top electrode is in the form of aluminum (Al) applied by vapor deposition. The thickness of the top electrode is 50-500 nm. The polymer capacitor is encapsulated with epoxy.

[0052] In the embodiment shown in Figure 2, different types of polymer capacitors are shown, from left to right: a polymer aluminum electrolytic capacitor (polymer Al-e-cap), a polymer tantalum electrolytic capacitor (polymer Ta-e-cap), and a hybrid polymer capacitor (hybrid polymer Al-e-cap). Furthermore, Figure 3 shows a perspective view and a cross-sectional view of a polymer Al-e-cap. Similarly, Figure 4a shows a perspective view and a cross-sectional view of a polymer Ta-e-cap, and Figure 4b shows a perspective view and a cross-sectional view of a hybrid polymer Al-e-cap.

[0053] As can be seen in Figure 3, a polymer capacitor 10 is shown comprising two terminals 1 and 1', a silver paste layer 2, and an encapsulation layer 3 in the form of a molded resin. In vertical cross section, aluminum foil 4 acts as the anode, aluminum oxide layer 5 acts as the dielectric, and polymer layer 6, comprising a solution-processed n-type conducting polymer, acts as the cathode.

[0054] Figure 4a shows yet another embodiment of a rectangular capacitor 210 having a tantalum anode 204, a tantalum pentoxide dielectric 205, a cathode layer 206 comprising a solution-processed n-type conductive polymer, and a silver paste layer 202. As can be seen in Figure 4a, the capacitor 210 comprises an encapsulation layer 203 in the form of a molded resin.

[0055] FIG. 4b shows a cylindrical polymer capacitor 310 comprising an aluminum anode 304, an aluminum oxide dielectric 305, a separator sheet 312, and a hybrid cathode 306 comprising a solution-processed n-type conductive polymer and an electrolyte impregnated into the separator sheet 312.

[0056] Figure 5 shows the change in conductivity of the polymer electrode after annealing in nitrogen at 200°C. As can be seen from the figure, the capacitor of the present invention shows almost no change in conductivity even after 8 hours, demonstrating excellent thermal stability.

[0057] The resin-encapsulated capacitor can be annealed in air with good results. As can be seen from Figure 6, even after 6 hours of annealing in air at 200°C, there was only a slight decrease in conductivity.

[0058] When the annealing temperature was increased to 300 °C, the thermal stability was impaired, and the conductivity decreased significantly already after 2 h in nitrogen atmosphere (Fig. 7).

[0059] The ink comprising the solution-processed n-type conductive polymer used in the polymer capacitor of the present invention exhibited excellent storage stability, as shown in FIG.

[0060] Figures 9a and 9b show the thermal stability of the n-type conductive polymer, i.e., polybenzodifurandione (PBFDO), used in the polymer capacitor of the present invention. As can be seen, PBFDO exhibits excellent thermal stability with little loss in conductivity up to 200°C. As confirmed in Figure 9c, the solution-processed n-type conductive polymer can be heat-resistant up to 225°C. The term "heat-resistant" means that the solution-processed n-type conductive polymer maintains conductivity in the film up to 225°C.

[0061] The polymer capacitors according to the invention and the reference capacitor were fabricated as follows: A commercially available anodized aluminum foil (ANOFOL, H18) with a thickness of 50 μm and an oxide layer of 4 μm was obtained from Steinert.

[0062] A reference sample was obtained using PEDOT:PSS as the conductive polymer. PEDOT:PSS (Clevios PH 1000 with 5 weight percent (wt%) ethylene glycol as a secondary dopant) was spin-coated (1500 rpm for 30 seconds) onto anodized aluminum and dried on a hotplate (110 °C). The PEDOT:PSS did not appear to penetrate the oxide layer, and resistances measured with a multimeter were in the 100 kΩ range (over 10 MΩ when measured directly on the oxide and less than 1 Ω when probing the unanodized foil).

[0063] The resistance and capacitance of the fabricated films were tested using a multimeter and an LCR meter. The resistance of the PEDOT:PSS film was around 400 Ω / square. The capacitance of this structure was around 20 nF. Probing the anodized aluminum oxide alone gave a capacitance of around 20 pF.

[0064] The samples of the present invention were obtained using PBFDO as the n-type conductive polymer, and spin-coated at 500 / 1000 rpm for 3 minutes, followed by 3000 rpm for 30 seconds.

[0065] Drying was performed on a hotplate at 40 °C for the inventive (n-ink) samples and at 110 °C for the reference (PEDOT:PSS) samples. A 100 nm thick top electrode was obtained by aluminum evaporation. The samples did not short circuit during processing (i.e., the conductive polymer did not penetrate the oxide).

[0066] Stray material from spin coating and evaporation was removed from the edges of the samples by applying and peeling off capton tape to prevent shorts caused by evaporated aluminum on the edges of samples that did not have a thick oxide layer.

[0067] One end of each strip was etched with 0.5 M sodium hydroxide (NaOH) to remove oxide and ensure electrical contact with the underlying aluminum (Al) electrode.

[0068] Three inventive samples and three reference samples were placed in a mold and the epoxy was cast in. Two inventive samples and two reference samples were placed in an oven without sealing.

[0069] The epoxy (COTRONICS Duralco 4460) was cured overnight at 120° C. The cure temperature was kept below 125° C. to prevent premature degradation of the polymer capacitors before capacitance testing.

[0070] Cables and alligator connectors were used to connect to the samples. The cables were capable of operating up to 200°C and contained aluminum shields. All shields were connected to each other and grounded. Nine cables were used, eight of which were used for the four caps and one for grounding or shielding.

[0071] The LCR meter was calibrated to the new setup and high temperature cables. All samples were measured at room temperature using both the LCR meter and potentiostat impedance spectroscopy before epoxy encapsulation.

[0072] The capacitors were tested at 125°C, 150°C, and 200°C, with LCR and impedance values ​​monitored twice a day at 200°C.

[0073] The capacitance results are summarized in Table 1. The measured capacitance and normalized capacitance of each sample before and after the high temperature test are shown. [Table 1]

[0074] Figure 10 shows the capacitance retention of the inventive sample and the reference sample as a function of time and temperature. As can be seen, the reference sample comprising PEDOT:PSS exhibits a continuous decrease in capacitance with increasing temperature. On the other hand, the inventive sample comprising n-ink appears to stabilize after an initial decrease. Figure 11 shows the capacitance values ​​of the samples.

[0075] Impedance spectroscopy was performed using an Ivium potentiostat in the frequency range 100–100,000 Hz and at a voltage of 10 mV AC.

[0076] The impedance data was modeled using the equivalent circuit shown in Figure 12. The model proposes three different capacitive layers / processes. The three components are Al / AlO x Al / AlO at the CP interface, the CP / Al double layer (due to mobile ions), and the contact area between the alligator clip and the sample. x / It has been suggested that it is metal.

[0077] The phase angles are plotted in Figure 13, showing which process dominates at various frequencies. An ideal capacitor would have a phase angle of -90° across all frequencies.

[0078] In both the n-ink and PEDOT:PSS capacitors, a small phase angle towards -90° is initially observed at high frequencies. This behavior is more pronounced in the PEDOT:PSS sample and is thought to be related to ionic resistance (dissipation) processes.

[0079] For the n-ink sample, the phase angle improves after encapsulation and heating, while for the PEDOT:PSS sample, there is no change. The reason for this difference is likely the ionic PSS-rich phase of PEDOT:PSS, which makes it a less ideal material for polymer capacitors.

[0080] The above samples were measured by an LCR meter and impedance spectroscopy (potentiostat) at RT (air), 125°C (vacuum), 150°C (vacuum), 200°C (vacuum), RT (vacuum), and RT (air).

[0081] Figure 13a shows the phase angle of the inventive sample before encapsulation, Figure 13b shows the phase angle of the inventive sample at 200°C, and Figure 13c shows the phase angle of the reference sample at 200°C. LCR meter data indicates that the capacitance degradation of the PEDOT:PSS sample is much faster than that of the n-ink sample, confirming that the n-ink capacitor is more stable at high temperatures. Furthermore, impedance spectroscopy data indicates that the capacitance behavior of the n-ink capacitor is more ideal than that of the PEDOT:PSS capacitor.

[0082] 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.

Claims

1. 1. A polymer capacitor comprising an anode, a dielectric layer, and a cathode, wherein the cathode comprises a solution-processed n-type conducting polymer having a conductivity of at least 100 S / cm, preferably at least 500 S / cm.

2. 10. The polymer capacitor of claim 1, wherein the solution-processed N-type conductive polymer has a heat resistance up to 225°C.

3. 3. The polymer capacitor of claim 1 or 2, wherein the solution-processed n-type conducting polymer has a work function of at least 4.7 eV, preferably at least 4.9 eV.

4. The polymer capacitor of any one of claims 1 to 3, wherein the solution-processed n-type conductive polymer does not contain side chains.

5. The anode is tantalum (Ta) and the dielectric layer is tantalum oxide (Ta ２ O ５ 5. The polymer capacitor according to claim 1, wherein

6. The anode is niobium (II) oxide (NbO) and the dielectric layer is niobium (V) oxide (Nb ２ O ５ 6. The polymer capacitor according to claim 1, wherein

7. The anode is aluminum (Al) and the dielectric layer is aluminum oxide (Al ２ O ３ 5. The polymer capacitor according to claim 1, wherein

8. 8. The polymer capacitor of claim 1, wherein the solution-processed n-type conductive polymer is poly(benzodifurandione) (PBFDO), 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.

9. The polymer capacitor of any one of claims 1 to 8, wherein the polymer capacitor is in the form of a rectangular SMD chip.

10. The polymer capacitor of any one of claims 1 to 8, wherein the polymer capacitor is in the form of a cylinder.

11. The polymer capacitor of any one of claims 1 to 10, wherein the polymer capacitor is encapsulated.

12. 1. A method for making a polymer capacitor comprising an anode, a dielectric layer, and a cathode, wherein the cathode comprises a solution-processed n-type conducting polymer having a conductivity of at least 100 S / cm, preferably at least 500 S / cm, the method comprising: a) providing an anode and a dielectric layer; b) applying a cathode material onto the dielectric layer to provide a polymer capacitor; c) drying the polymer capacitor; The method comprising:

13. The method comprises: a) encapsulating the polymer capacitor 13. The method of claim 12, further comprising:

14. The method comprises: a') anodizing the anode material to prepare the anode and dielectric layer; and The method according to claim 12 or 13, wherein step a') is carried out before step a).

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