Conductive ink compositions comprising gold and methods for making the same

Abstract

To provide conductive ink compositions comprising gold and methods for making the same.SOLUTION: A particle-free gold-complex based ink is described where a gold carboxylate is complexed with an amine. Upon heating the solution, the gold cation catalyzes the oxidative amidation of the amine with the carboxylate to form a short-chain or polymeric amide while simultaneously reducing the gold cation to metallic gold. This method is extremely versatile and allows preparation of both pure metallic gold films and polymer gold composites with unique properties. In one aspect, ink compositions for making a conductive gold structure are provided which comprise a gold salt and a complexing agent, and optionally further comprises a short-chain carboxylic acid or salt thereof, where the gold salt is a carboxylate or is capable of forming a carboxylate with the short-chain carboxylic acid or salt thereof.SELECTED DRAWING: None

Description

[Technical field]

[0001] CITED RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Patent Application No. 62 / 540,903, filed Aug. 3, 2017, the disclosure of which is incorporated by reference in its entirety herein.

[0002] FIELD OF THEINVENTION The present disclosure relates generally to conductive gold ink compositions and methods for making same. [Background technology]

[0003] 2. Background of the Invention The majority of commercially produced conductive inks are specifically designed for inkjet, screen printing, or roll-to-roll processing to process large areas with fine-scale features in short periods of time. These inks have disparate viscosity and synthesis parameters. Particle-based inks are based on conductive metal particles, which are typically synthesized separately and then incorporated into an ink formulation. The resulting ink is then tailored for the specific particle process. Precursor-based inks are based on thermally unstable precursor complexes that are reduced to conductive metals upon heating. Previous particle-based and precursor-based methods generally rely on high temperatures to form conductive coatings and therefore may not be compatible with substrates that require low processing temperatures to maintain their integrity.

[0004] There is a need in the art for better compositions and methods for producing high quality conductive metallic inks at conversion temperatures lower than those of existing conductive ink compositions (e.g., silver-based inks). There is also a need for ink compositions that are stable and can be stored at room temperature. Summary of the Invention [Means for solving the problem]

[0005] Described herein are improved ink compositions for forming conductive structures comprising gold and methods of making said conductive structures.

[0006] In one aspect, disclosed herein is an ink composition for making conductive gold structures, the ink composition comprising a gold salt; and a complexing agent, and optionally further comprising a short chain carboxylic acid or salt thereof, where the gold salt is a carboxylate or can form a carboxylate with the short chain carboxylic acid or salt thereof.

[0007] In some embodiments, the gold salt is a gold(I) salt, a gold(II) salt, or a gold(III) salt. In some embodiments, the gold salt is or includes gold(III) formate, gold(III) acetate, gold(III) propionate, gold(III) lactate, gold(III) oxalate, gold(III) carbonate, gold(III) nitrate, gold(III) nitrite, gold(III) phosphate, gold(III) oxide, gold(III) fluoride, gold(III) bromide, gold(I) chloride, gold(III) chloride, gold(III) chloride trihydrate, gold(III) hydroxide, gold(I) iodide, hydrogen tetrabromoaurate(III) hydrate, potassium gold(III) chloride, or gold(III) terephthalate.

[0008] In some embodiments, the gold salt is a gold carboxylate.

[0009] In some embodiments, the molar ratio of complexing agent to the gold salt is approximately 6:1.

[0010] In some embodiments, the complexing agent is or comprises an alkylamine or ammonia, hi some embodiments, the alkylamine is or comprises a primary amine, a secondary amine, or a polyamine.

[0011] In some embodiments, the alkylamine is selected from the group consisting of methylamine, dimethylamine, ethylamine, diethylamine, propylamine, dipropylamine, butylamine, dibutylamine, amylamine, isoamylamine, dipentylamine, and combinations thereof.

[0012] In some embodiments, the alkylamine is selected from the group consisting of methylamine, dimethylamine, ethylamine, diethylamine, propylamine, dipropylamine, butylamine, dibutylamine, amylamine, dipentylamine, and combinations thereof.

[0013] In some embodiments, the short chain carboxylic acid is selected from the group consisting of formic acid, acetic acid, propionic acid, lactic acid, oxalic acid, citric acid, and citraconic acid.

[0014] In some embodiments, the citraconic acid is produced from citraconic anhydride.

[0015] In some embodiments, the short chain carboxylic acid is selected from the group consisting of formic acid, acetic acid, propionic acid, lactic acid, oxalic acid, and citric acid.

[0016] In some embodiments, the composition further comprises methylenediamine or ethylenediamine.

[0017] In some embodiments, the composition further comprises a solvent selected from the group consisting of ethanol, butanol, propylene glycol, water, and combinations thereof.

[0018] In some embodiments, the gold salt is gold(III) formate and the complexing agent is selected from the group consisting of methylamine, dimethylamine, ethylamine, diethylamine, propylamine, dipropylamine, butylamine, dibutylamine, amylamine, dipentylamine, ammonia, and combinations thereof.

[0019] In some embodiments, the complexing agent is selected from the group consisting of methylamine, dimethylamine, ethylamine, diethylamine, propylamine, dipropylamine, butylamine, dibutylamine, amylamine, dipentylamine, ammonia, and combinations thereof, and the short chain carboxylic acid is acetic acid.

[0020] In some embodiments, the composition further comprises ethylenediamine.

[0021] In some embodiments, the composition further comprises a solvent selected from the group consisting of ethanol, butanol, propylene glycol, water, and combinations thereof.

[0022] In another aspect, disclosed herein is an alternative ink composition for making conductive structures comprising gold. The ink composition comprises a gold salt of an organic acid; a monomer component; and about 16 a solvent having a boiling point at or below 0° C.; where the conjugate base of the organic acid reacts with the monomer building blocks to form a polymer during which ionic gold is reduced to elemental gold.

[0023] In some embodiments, the polymer is a polyamide, polyimide, polyamideimide, or polyester.

[0024] In some embodiments, the organic acid comprises a dicarboxylic acid selected from the group consisting of oxalic acid (ethanedioic acid), malonic acid (propanedioic acid), succinic acid (butanedioic acid), glutaric acid (pentanedioic acid), adipic acid (hexanedioic acid), pimelic acid (heptanedioic acid), suberic acid (octanedioic acid), azelaic acid (nonanedioic acid), sebacic acid (decanedioic acid), undecanedioic acid, dodecanedioic acid, tridecanedioic acid, hexadecanedioic acid, and terephthalic acid.

[0025] In some embodiments, the monomeric component comprises a diamine, an N-silylated diamine, or a diisocyanate.

[0026] In some embodiments, the diamine comprises a linear aliphatic diamine, a branched aliphatic diamine, a cycloaliphatic diamine, or an aromatic diamine.

[0027] In some embodiments, the monomer building blocks are selected from the group consisting of ethylenediamine (1,2-diaminoethane), N-alkylated diamines, 1,1-dimethylethylenediamine, 1,1-dimethylethylenediamine, tetramethylethylenediamine (TMEDA), ethambutol, TMEDA, 1,3-diaminopropane (propane-1,3-diamine), putrescine (butane-1,4-diamine), cadaverine (pentane-1,5-diamine), or hexamethylenediamine (hexane-1,6-diamine), ethylenediamine, 1,2-diaminopropane, diphenylethylenediamine, trans-1,2-diaminocyclohexane, 1,4-diazacycloheptane, o-xylylenediamine (OXD), m-xylylenediamine (MXD). , p-xylylenediamine (PXD), o-phenylenediamine (OPD), m-phenylenediamine (MPD), p-phenylenediamine (PPD), 2,5-diaminotoluene, N-methylated derivatives of phenylenediamine, imethyl-4-phenylenediamine, N,N'-di-2-butyl-1,4-phenylenediamine, diamines having two aromatic rings, 4,4'-diaminobiphenyl or 1,8-diaminonaphthalene, toluene diisocyanate (TDI), methylene diphenyl diisocyanate (MDI), hexamethylene diisocyanate (HDI), methyl isocyanate (MIC), and isophorone diisocyanate (IPDI).

[0028] In some embodiments, the polymer is a polyimide formed from a poly(amic acid) precursor, a polyisoimide precursor, a mixture of diester-acids and diamines, a mixture of tetracarboxylic acids and diamines, a mixture of dianhydrides and diisocyanates, a polyetherimide via a nucleophilic aromatic substitution reaction, or a mixture of 4,4'-methylenediphenyldiisocyanate (MDI) and trimellitic anhydride (TMA).

[0029] In some embodiments, the polyester is selected from the group consisting of polyethylene adipate (PEA), polybutylene succinate (PBS), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polyethylene naphthalate (PEN), and Vectran.

[0030] In yet another aspect, a method for making a conductive structure comprising gold is disclosed herein, the method comprising the steps of: providing a metal salt composition comprising a gold salt and a complexing agent; adding a short-chain carboxylic acid or a salt of the short-chain carboxylic acid to the combined metal salt composition and complexing agent to form an ink composition; optionally partially evaporating the complexing agent from the ink composition to form a concentrated formulation; and reducing the metal salt composition to form a conductive structure comprising gold, where the concentrated formulation and the conductive structure comprising gold are formed at a temperature of about 160° C. or lower.

[0031] In some embodiments, the temperature is about 140° C. or lower.

[0032] In some embodiments, the short chain carboxylic acid or salt of the short chain carboxylic acid is not added until after the gold salt has dissolved in the complexing agent.

[0033] In some embodiments, the method further comprises depositing the ink composition on a substrate.

[0034] In some embodiments, the ink composition is deposited on the substrate by a method selected from the group consisting of spray processing, dip coating, spin coating, inkjet printing, and e-jet printing.

[0035] In some embodiments, the method further comprises depositing the concentrated formulation onto a substrate.

[0036] In some embodiments, the concentrated formulation is deposited on the substrate by a method selected from the group consisting of screen printing, roll-to-roll processing, and direct ink writing.

[0037] In yet another aspect, disclosed herein is an alternative method for making a conductive structure comprising gold, the method comprising providing a gold salt of an organic acid and a monomer building block; and causing polymer formation between a conjugate base of the organic acid and the monomer building block.

[0038] Those skilled in the art will understand that any embodiment disclosed herein may be applied in any aspect, if applicable. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0039] Detailed Description of the Invention Disclosed herein is a precursor-based gold conductive ink composition that preferably includes one or more of the following features. First, the formation of gold conductive structures from the ink composition can be catalyzed by gold ions in the ink itself in the absence of a catalyst. This feature is fundamentally different from previously known precursor-based conductive inks (e.g., the silver conductive ink composition disclosed in U.S. Pat. No. 9,469,773). Second, the elemental gold produced from the ink composition is pure and uncontaminated with by-products. Third, the ink composition can have low viscosity so as to be compatible with a wide range of patterning techniques, including direct ink writing, inkjet printing, and airbrush spraying. Fourth, patterned features prepared using the ink can be highly conductive at room temperature and can achieve bulk conductivity upon annealing at mild temperatures (e.g., <140° C.).

[0040] As used herein, the terms "conductive ink composition," "conductive ink," "ink composition," "ink," or variations thereof may be used interchangeably.

[0041] As disclosed herein, a conductive "gold ink composition" refers to an ink composition that includes, but is not limited to, a gold salt. For example, although disclosure of solvents and complexing agents that include a gold salt is provided herein, this disclosure should in no way limit the ink composition to compositions that include a gold salt as the only metal source. In some embodiments, a conductive gold ink composition may include another metal salt; for example, a palladium salt may be added to promote the stability of the conductive ink.

[0042] In one aspect of the present disclosure, gold conductive structures are obtained through a gold-catalyzed amidation reaction. For example, a gold salt (e.g., a gold carboxylate) can be dissolved in an amine solution, where the amine reacts with the carboxyl group in the gold carboxylate to form an amide, and the ionic gold is reduced to elemental form. In such a reaction, the amine functions as both a complexing agent and a reducing agent.

[0043] The gold-catalyzed amidation reaction may occur at a temperature of approximately 120° C. At such a temperature, all of the liquid product is evaporated, leaving only the conductive elemental gold. However, in some cases, it may be advantageous to carry out the reaction at a lower temperature, for example, approximately 100° C., approximately 80° C., approximately 60° C., or even lower. The inventors have discovered that the temperature of the reaction may be controlled by the selection of the carboxylic acid used to form the gold carboxylate. For example, the reaction temperature may be as low as 60° C., or even lower, by selecting an appropriate carboxylic acid for use in the ink composition. In some cases, a liquid product may remain after the formation of elemental gold. The remaining liquid product may be removed by evaporation in a subsequent step, or by other means, as appropriate for the situation and conditions.

[0044] Thus, in some embodiments, an ink composition for making conductive gold structures is provided, the ink composition comprising a gold salt, and a complexing agent, and optionally further comprising a short chain carboxylic acid or salt thereof, where the gold salt is a carboxylate or the gold salt can form a carboxylate with the short chain carboxylic acid or salt thereof. Stated another way, the present disclosure provides an ink composition for making conductive gold structures, the ink composition comprising a gold salt; and one of (a) a complexing agent; (b) a complexing agent and a short chain carboxylic acid, or (c) a complexing agent and a salt of a short chain carboxylic acid, where the gold salt is a carboxylate or the gold salt can form a carboxylate with the short chain carboxylic acid or salt thereof.

[0045] Gold salts that find use in the compositions of the present invention include, but are not limited to, gold(III) formate, gold(III) acetate, gold(III) propionate, gold(III) lactate, gold(III) oxalate, or mixtures thereof. In some embodiments, gold(III) butyrate and gold(III) pentanoate may also be used if their reaction temperatures are higher.

[0046] Additional gold salts may also be used, including gold(I) salts and gold(II) salts.

[0047] In some embodiments, the reaction temperature is 180° C. or less, 170° C. or less, 160° C. or less, 150° C. or less, 140° C. or less, 130° C. or less, 120° C. or less, 110° C. or less, 100° C. or less, 90° C. or less, 100° C. or less, 110° C. or less, 120° C. or less, 130° C. or less, 140° C. or less, 150° C. or less, 160° C. or less, 170° C. or less, 180° C. or less, 180° C. or less, 190° C. or less, 200° C. or less, 210° C. or less, 220° C. or less, 230° C. or less, 240° C. or less, 250° C. or less, 260° C. or less, 270° C. or less, 280° C. or less, 290° C. or less, 300° C. or less, 310° C. or less, 320° C. or less, 330° C. or less, 340° C. or less, 350° C. or less, 360° C. or less, 370° C. or less, 380° C. or less, 390° C. or less, 400° C. or less, 410° C. or less, 420° C. or less, 430° C. or less, 440° C. or less, 450° C. or less, 460° C. or less, 470° C. or less, 480° C. or less, 490 °C or lower, or 80 °C or lower. In some embodiments, the reaction temperature may be greater than 180 °C.

[0048] In some embodiments, the only conductive material in the gold ink composition is gold. In some embodiments, multiple conductive materials are included in the gold ink; for example, palladium may be used as a stabilizing agent. Further information regarding the stabilizing properties of palladium may be found in U.S. Provisional Patent Application No. 62 / 540,829, filed Aug. 3, 2017, entitled "Conductive Ink Compositions Comprising Palladium and Methods for Making the Same," which is incorporated by reference in its entirety.

[0049] In one embodiment, the complexing agent is an alkylamine. To form a conductive ink, the gold salt is dissolved in the alkylamine. The alkylamine contains at least one C 1-8An amino group substituted with an alkyl group, where the alkyl group has a specified number of carbon atoms (i.e., C 1-8 means 1 to 8 carbon atoms), linear, cyclic, or branched, or a combination thereof. Examples of alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, t-butyl, isobutyl, sec-butyl, pentyl, isopentyl, cyclohexyl, cyclopentyl, and the like. The alkylamine can be a primary amine, secondary amine, or tertiary amine, preferably a primary amine. In some cases, one or more of the carbon atoms in the alkyl group can be replaced with a heteroatom (e.g., oxygen, sulfur, or nitrogen).

[0050] The alkylamine, which is a weak base, acts as a reducing agent for the gold salt through an amidation reaction. In addition, the alkylamine also functions as a stabilizer and solvent for the gold salt. Any suitable alkylamine that reduces or stabilizes the gold salt or additional metal salt may be used. In some embodiments, the alkylamine has a boiling point of about 140° C. or lower. In some embodiments, the alkylamine has a boiling point of about 120° C. or lower. In some embodiments, the alkylamine has a boiling point of about 100° C. or lower. Examples of alkylamines that have a boiling point of about 120° C. or lower include CH 15 N isomer, CH 13 N isomers, CH 11Examples of alkylamines include, but are not limited to, isomers of N, isomers of CHN, isomers of CHN, and isomers of CHN. For ease of handling, it may be desirable for the alkylamine to have a boiling point of about 40°C or higher. Examples of alkylamines having a boiling point between about 40°C and 180°C include, but are not limited to, methylamine, ethylamine, aniline, propylamine, n-butylamine, amylamine, isoamylamine, s-butylamine, isobutylamine, isopentylamine, 1-methylbutylamine, 1-amino-2-methylbutane, N-methyldiethylamine, diethylamine, dipropylamine, dibutylamine, and dipentylamine. Alkylamines containing ether linkages, such as methoxyethylamine, are also believed to be suitable for use in the compositions of the present invention. Preferably, the amine is propylamine, n-butylamine, or amylamine; more preferably, propylamine or n-butylamine.

[0051] In some embodiments, the alkylamine is selected from the group consisting of methylamine, ethylamine, propylamine, butylamine, amylamine, isoamylamine, and methoxyethylamine. In some embodiments, the alkylamine is selected from the group consisting of methylamine, ethylamine, propylamine, butylamine, and amylamine.

[0052] The alkylamine may be selected based on its boiling point for a particular application. For deposition methods (e.g., inkjet printing or e-jet), greater stability is generally preferred, and therefore it may be preferable to use an alkylamine with a higher boiling point (e.g., amylamine with a boiling point of about 104°C). In some aspects, it may be desirable to add a short chain diamine (e.g., methylenediamine or ethylenediamine) in addition to the alkylamine to provide even greater stability. However, if ethylenediamine is used alone, the conductivity of the resulting gold-containing product may not be as high as desired. Therefore, it may be advantageous to use a combination of alkylamine and ethylenediamine (e.g., a ratio of amylamine and ethylenediamine to prepare a gold-based ink). Alkylamine vs. The ratio of ethylenediamine, on a volume:volume basis, can range from about 4:1 to about 1:4, and is preferably about 1:1. Another short chain diamine, such as methylenediamine, can be used in place of or in addition to ethylenediamine.

[0053] In some embodiments, sufficient alkylamine may be added to facilitate the amidation reaction between the short chain gold carboxylate and the alkylamine to form the conductive ink. Preferably, an excess of alkylamine compared to the short chain carboxylic acid is used to ensure that the short chain carboxylic acid is not available to be complexed and thereby act as a reducing agent. The molar ratio of the alkylamine to the short chain carboxylate is at least about 1:1, preferably at least about 3:1, and more preferably at least about 6:1. In some embodiments, the molar ratio of the alkylamine to the short chain carboxylate is greater than 6:1. For ease of operation, it may be desirable to add sufficient amine to dissolve the gold salt or any additional metal salt. The amount of alkylamine required may be determined by slowly adding the alkylamine to the gold salt and any additional metal salt and monitoring the dissolution of the gold salt and any additional metal salt. In some aspects, about 2 mL of alkylamine may be used to dissolve about 1 g of gold salt or any additional metal salt. Other methods known to those skilled in the art to aid in the dissolution of the gold salt and any additional metal salts are also contemplated, including the addition of solvents or other components (e.g., higher molecular weight alkyl amines or diamines) to aid in dissolution.

[0054] In some aspects, it may be desirable to add a solvent to the mixture of alkylamine and gold salt (and any additional metal salts). The solvent preferably has a boiling point of at most 180° C. Examples of suitable solvents include water, alcohols (including, for example, methanol, ethanol, 1-propanol, and 2-propanol), esters, ketones, and ethers. Preferably, the solvent is water, ethanol, butanol, or propylene glycol. In some aspects, the solvent may include two or more co-solvents. For example, the solvent may include water and another co-solvent (e.g., butanol or propylene glycol).

[0055] In another embodiment, the complexing agent is ammonium hydroxide (e.g., ammonia or aqueous ammonia). To form the conductive ink, the gold salt (and any additional metal salts, if applicable) are dissolved in the ammonium hydroxide. The ammonium hydroxide, which is a weak base, acts as a stabilizer and solvent for the gold salt (and any additional metal salts, if applicable). The ammonium hydroxide is not intended to act as a reducing agent for the gold ink composition (i.e., it does not appreciably reduce the gold salt or any additional metal salts, if applicable).

[0056] In another aspect of the disclosure, a short-chain carboxylic acid may be added to the composition (e.g., in addition to the gold carboxylate and alkylamine) to form the conductive ink composition. In any of the embodiments described herein, preferably after dissolving the gold salt (and any additional metal salt, if applicable) in the complexing agent, the short-chain carboxylic acid is added to form the ink formulation. The short-chain carboxylic acid may function as a reducing agent for the gold salt (and any additional metal salt, if applicable). Alternatively, or in addition, a salt (e.g., an ammonium salt) of the short-chain carboxylic acid may be added to form the ink formulation. The salt of the short-chain carboxylic acid may function as a reducing agent for the gold salt (and any additional metal salt, if applicable), generally as described herein with reference to the short-chain carboxylic acid. Without wishing to be bound by theory, it is believed that by adding a short chain carboxylic acid in the presence of a complexing agent, an acid-base complex is formed between the short chain carboxylic acid and the complexing agent, thereby preventing the short chain carboxylic acid from immediately reducing the gold salt (and any further salts, if applicable). As the ink formulation is concentrated and the complexing agent is removed by appropriate conditions, including evaporation, the short chain carboxylic acid is liberated and reduction of the gold salt to elemental gold (gold in zero oxidation state) by the short chain carboxylic acid can occur. If one or more further metal salts are present (e.g., silver or palladium salts), the further metal salts are also reduced to their corresponding elemental metal forms.

[0057] In some embodiments, the short chain carboxylic acid may have a chain length of 7 carbons or less, typically 5 carbons or less. Examples of short chain carboxylic acids include, but are not limited to, formic acid, acetic acid, propionic acid, butyric acid, and pentanoic acid. Preferably, the short chain carboxylic acid has a chain length of 2 carbons or less. More preferably, the short chain carboxylic acid is formic acid. Formic acid has been found to be particularly advantageous due to its low boiling point and volatile by-products. Formic acid contains aldehyde functionality, which enhances its reducing ability. As the gold salt is reduced to elemental gold, formic acid is then oxidized to a carboxylic acid, which in turn forms carbon dioxide and water, both of which are volatile by-products. Thus, short chain carboxylic acids containing aldehyde functionality are preferred short chain carboxylic acids. Furthermore, the use of formic acid can result in the formation of carbon dioxide and water, leaving no residual reducing agent.

[0058] In an alternative aspect of the present disclosure, the short chain carboxylic acid is a reducing agent for the gold salt (or any additional metal salt, if applicable), but the acid is substantially prevented from reducing the gold salt due to complexation with the complexing agent that occurs upon adding the short chain carboxylic acid to the mixture. Generally, reduction of the gold salt does not occur until the complexing agent is partially or completely evaporated from the ink formulation. The complexing agent may be evaporated after depositing the ink formulation on a desired substrate. At that point, the acid reduces the gold salt to form a conductive gold coating or other gold structure on the substrate. Alternatively, the complexing agent may be partially evaporated from the ink during further processing steps to increase the viscosity of the ink and form a concentrated formulation for use in printing techniques (e.g., direct ink writing). In this case, prior to deposition, partial reduction of the gold salt occurs, so that the ink may have a composite structure that includes a mixture of unreacted gold salt along with conductive gold particles (e.g., nanocrystals) formed during the partial reduction. The viscosity of such composite inks may be tailored for printing techniques such as direct ink writing, where the ink must spread into gaps during the fabrication of three-dimensional structures. Evaporation of the complexing agent typically occurs at elevated temperatures below about 120° C., or between about 50° C. and 100° C., or between about 60° C. and 90° C. The evaporation may occur over a period of minutes or hours, depending on the volatility of the complexing agent and the temperature at which the evaporation is performed. The complexing agent may also evaporate at room temperature for longer periods. The reaction may be evaporated at room temperature. In some cases, the evaporation may be performed under reduced pressure. In embodiments where a silver salt is present as the additional metal salt, UV light may also be used to accelerate the reaction in place of heat, since UV light reduces the silver salt.

[0059] In some embodiments, it may be desirable to add a solvent to the mixture of ammonium hydroxide and gold salt (and any additional metal salts, if applicable). The solvent preferably has a boiling point of up to 160° C. Examples of suitable solvents include water, alcohols (including, for example, methanol, ethanol, 1-propanol, and 2-propanol), esters, ketones, and ethers. Preferably, the solvent is water or ethanol.

[0060] Preferably, particle formation can occur only after pattern formation when evaporation continues. Highly conductive gold structures remain after reduction even at low processing temperatures because the low boiling points of the non-gold components allow for controlled and complete or near complete removal of the non-gold components.

[0061] In another aspect, the gold conductive structures are obtained through gold-catalyzed polymerization. For example, elemental gold can be formed by combining a gold salt of an organic acid with a monomer component, where the conjugate base of the organic acid reacts with the monomer component to form a polymeric material while yielding elemental gold. In some embodiments, the resulting polymer is a polyamide. In some embodiments, the resulting polymer is a polyimide. In some embodiments, the resulting polymer is a polyamideimide. In some embodiments, the resulting polymer is a polyester.

[0062] Typically, polyamide formation requires an activating group (e.g., carbonyl chloride) in addition to the carboxylate and diamine components for polymerization to occur at low temperatures (<140° C.). Harmful by-products (e.g., hydrochloric acid) are often formed. As disclosed herein, elemental gold can function as a catalyst to avoid the formation of harmful by-products.

[0063] In some embodiments, the polyamide is formed between a gold salt of an organic acid and a diamine, hi some embodiments, the polyamide is formed with a diisocyanate and a gold salt of an organic acid.

[0064] In some embodiments, the organic acid is a dicarboxylic acid.Exemplary dicarboxylic acids include, but are not limited to, oxalic acid (ethanedioic acid), malonic acid (propanedioic acid), succinic acid (butanedioic acid), glutaric acid (pentanedioic acid), adipic acid (hexanedioic acid), pimelic acid (heptanedioic acid), suberic acid (octanedioic acid), azelaic acid (nonanedioic acid), sebacic acid (decanedioic acid), undecanediic acid, dodecanediic acid, tridecanediic acid, hexadecanedioic acid, and terephthalic acid.In some embodiments, the organic acid is terephthalic acid.

[0065] In some embodiments, the monomeric component is a diamine. In some embodiments, the monomeric component is an N-silylated diamine. In some embodiments, the monomeric component is a diisocyanate.

[0066] In some embodiments, the diamine is a linear aliphatic diamine (ethylenediamine (1,2-diaminoethane), N-alkylated diamines, 1,1-dimethylethylenediamine, 1,1-dimethylethylenediamine, tetramethylethylenediamine (TMEDA), ethambutol, TMEDA, 1,3-diaminopropane (propane-1,3-diamine), putrescine (butane-1,4-diamine), cadaverine (pentane-1,5 -diamine), or hexamethylenediamine (hexane-1,6-diamine).

[0067] In some embodiments, the diamine is a branched aliphatic diamine, including but not limited to, ethylenediamine or a derivative thereof, such as 1,2-diaminopropane, diphenylethylenediamine, or trans-1,2-diaminocyclohexane.

[0068] In some embodiments, the diamine is a cycloaliphatic diamine (e.g., 1,4-diazacycloheptane). In some embodiments, the diamine is a xylylenediamine (including, but not limited to, o-xylylenediamine (OXD), m-xylylenediamine (MXD), or p-xylylenediamine (PXD).

[0069] In some embodiments, the diamine is an aromatic diamine, including but not limited to, o-phenylenediamine (OPD), m-phenylenediamine (MPD), p-phenylenediamine (PPD), or 2,5-diaminotoluene (which is related to PPD but contains a methyl group on the ring).

[0070] In some embodiments, the diamines include various N-methylated derivatives of phenylenediamines, such as dimethyl-4-phenylenediamine or N,N'-di-2-butyl-1,4-phenylenediamine.

[0071] In some embodiments, the diamine includes a diamine having two aromatic rings and its derivatives, such as 4,4'-diaminobiphenyl or 1,8-diaminonaphthalene.

[0072] In some embodiments, the diisocyanate includes, but is not limited to, toluene diisocyanate (TDI), methylene diphenyl diisocyanate (MDI), hexamethylene diisocyanate (HDI), methyl isocyanate (MIC), or isophorone diisocyanate (IPDI).

[0073] In some embodiments, the polymer is a polyimide derivatized from a poly(amic acid) precursor. In some embodiments, the polyimide is formed from a polyisoimide precursor. In some embodiments, the polyimide is formed from a diester-acid and a diamine. In some embodiments, the polyimide is formed from a tetracarboxylic acid and a diamine. In some embodiments, the polyimide is formed from a dianhydride and a diisocyanate. In some embodiments, the polyimide is formed from a polyetherimide via a nucleophilic aromatic substitution reaction.

[0074] In some embodiments, the polymer is a polyamideimide formed, for example, between 4,4'-methylenediphenyldiisocyanate (MDI) and trimellitic anhydride (TMA).

[0075] In some embodiments, the polymer is a polyester formed between a gold salt of a dicarboxylic acid and a diol. Exemplary polyesters include polyethylene adipate (PEA), polybutylene succinate (PBS), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (P TT), polyethylene naphthalate (PEN) or Vectran. [Table 1]

[0076] In some embodiments, it may be desirable to add a solvent to the polymerization mixture of the gold salt and monomer components. The solvent preferably has a boiling point of at most 160° C. Examples of suitable solvents include water, alcohols (including, for example, methanol, ethanol, 1-propanol, and 2-propanol), esters, ketones, and ethers. Preferably, the solvent is water or ethanol.

[0077] It will be readily apparent to those skilled in the relevant art that other suitable modifications and adaptations to the methods and applications described herein may be made without departing from the scope of the invention or any of its embodiments. Now that the invention has been described in detail, the invention will be more clearly understood by reference to the following examples, which are included herein for illustrative purposes only and are not intended to be limitations of the invention. EXAMPLES

[0078] The following non-limiting examples are provided to further illustrate embodiments of the invention disclosed herein. It should be appreciated by those skilled in the art that the techniques disclosed in the examples that follow represent approaches found to work well in the practice of the invention and therefore may be considered to constitute examples of modes for its practice. However, those skilled in the art should appreciate in light of this disclosure that many changes can be made in the specific embodiments disclosed and still obtain the same or similar results without departing from the spirit and scope of the invention.

[0079] Example 1. Gold-catalyzed amidation Gold ion inks can be made by complexation with six nitrogens from the group consisting of ammonia, primary amines, secondary amines, or polyamines and stoichiometric amounts of carboxylate counterions relative to the ionic valence of the gold species. For example, typically gold(III) acetate can be dissolved in ammonia or an amine to produce its corresponding amide at moderate temperatures (80-140°C). Other carboxylate counterions could be used (e.g., from gold salts). polycarboxylates or other single carboxylates.

[0080] Additionally, gold oxide or other gold salts could be dissolved in solution with their corresponding carboxylic acid and nitrogen-containing groups to make their corresponding amides or polyamides.

[0081] For example, 1 mMol of Au(III) acetate was dissolved in 6 mMol of dibutylamine to produce a largely particle-free translucent yellow solution. Upon deposition on a substrate and heating to 120° C., a gold film was formed during the formation of dibutylacetamide.

[0082] Similarly, when 6 mMol of methylamine was used, a gold film was formed at 120° C. while methylacetamide was produced.

[0083] When an electron-withdrawing group, such as a halide (preferentially fluoride), was added to an amine, such as perfluorinated dibutylamine, the reaction took place at much lower temperatures, in some cases as low as 80° C.

[0084] Example 2. Gold-catalyzed polymerization Here, Au(III) terephthalate was mixed with 1,4-phenylenediamine in alcohol. At 120°C, the solution polymerized in less than 5 minutes. At 100°C, the solution polymerized in less than 10 minutes. Remarkably, the polymer film was immediately metallized with a gold film on the surface without any by-products.

[0085] Example 3. Alternative Gold Ink Compositions An alternative gold ink composition is provided as follows: Au(III) citraconic acid salt is synthesized by mixing gold(III) hydroxide and citraconic anhydride in a molar ratio (1:1.5-1:4) as a slurry in methanol. The Au(III) citraconic acid precipitate is isolated by evaporating the solvent and washing with methanol. The resulting solid is mixed with amylamine in a 6:1 ratio to form a translucent solution of Au(III) citraconic acid. This solution is then deposited on a substrate and heated to 100°C for 5-10 minutes. At this temperature, the solution completely decomposes to metallic gold and forms a continuous, highly conductive film (<0.1 ohms per square (OPS)).

[0086] The above various methods and techniques provide many ways to implement the present invention. Of course, it should be understood that not all of the objects or advantages described can necessarily be achieved according to any particular embodiment described herein. Thus, for example, a person skilled in the art will recognize that the method can be performed in a manner that achieves or optimizes one or a group of advantages as taught herein, even if it does not necessarily achieve other objects or advantages as taught or suggested herein. Various advantageous and disadvantageous alternatives are mentioned herein. It should be understood that some preferred embodiments specifically include one, another, or several advantageous features, while others specifically exclude one, another, or several disadvantageous features, while still others can specifically alleviate a current disadvantageous feature by the inclusion of one, another, or several advantageous features.

[0087] Moreover, those skilled in the art will recognize the applicability of various features from different embodiments. Similarly, the various elements, features, and steps discussed above, as well as other known equivalents of each such element, feature, or step, may be mixed and matched by those skilled in the art to practice methods in accordance with the principles described herein. Among the various elements, features, and steps, some are specifically included and others are specifically excluded in various embodiments.

[0088] While the present invention has been disclosed in the context of certain embodiments and examples, it will be understood by those skilled in the art that the embodiments of the present invention extend beyond the specifically disclosed embodiments to other alternative embodiments and / or uses and modifications and equivalents thereof.

[0089] Many variations and alternative elements are disclosed in the embodiments of the invention, and still further variations and alternative elements will be apparent to those of ordinary skill in the art.

[0090] In some embodiments, the numbers expressing quantities of ingredients, properties (e.g., molecular weight, reaction conditions, etc.) used to describe and claim certain embodiments of the invention should be understood to be modified in some cases by the term "about". Thus, in some embodiments, the numerical parameters set forth in the written description and accompanying claims are approximations that may vary depending on the desired properties sought to be obtained by a particular embodiment. In some embodiments, the numerical parameters should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of some embodiments of the invention are approximations, the numerical values ​​set forth in the specific examples are reported as precisely as possible. The numerical values ​​set forth in some embodiments of the invention may contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements.

[0091] In some embodiments, the terms "a" and "an" and "this, its, the" and similar references used in the context of describing certain embodiments of the invention (particularly in the context of certain of the claims below) can be interpreted to cover both the singular and the plural. The recitation of ranges of values ​​herein is merely intended to serve as a shorthand method of individually referring to each separate value falling within the range. Unless otherwise indicated herein, each separate value is incorporated herein as if it were individually set forth herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by the context. The use of any and all examples or exemplary language (e.g., "such as") provided in connection with certain embodiments herein is intended merely to better illustrate the invention and does not pose a limitation on the scope of the invention as otherwise claimed. No language in this specification should be construed as indicating any non-claimed element essential to the practice of the invention.

[0092] The classification of alternative elements or embodiments of the invention disclosed herein should not be construed as limiting. Each group member may be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group may be included in or deleted from a group for reasons of convenience and / or patentability. When any such inclusion or deletion occurs, the specification is hereby deemed to be modified and thus include the group as fulfilling the written description of all Markush groups used in the appended claims.

[0093] Preferred embodiments of the invention are described herein. Variations to those preferred embodiments will become apparent to those of skill in the art upon reading the foregoing description. Those of skill in the art may use such variations where appropriate, and it is contemplated that the invention may be practiced in other ways than as specifically described herein. Accordingly, many embodiments of the invention include all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is intended to be included in the present invention unless otherwise indicated herein. or otherwise, are encompassed by the present invention unless the circumstances clearly contradict.

[0094] Additionally, various references have been made throughout this specification to patents and printed publications. Each of the above cited references and printed publications is individually incorporated herein by reference in its entirety.

[0095] In closing, it should be understood that the embodiments of the invention disclosed herein are illustrative of the principles of the invention. Other modifications that may be employed are within the scope of the invention. Thus, by way of illustration, but not of limitation, alternative configurations of the invention may be utilized in accordance with the teachings herein. Thus, the embodiments of the invention are not limited to those precisely as shown and described. For example, the present invention provides the following: (Item 1) 1. An ink composition for producing conductive gold structures, said ink composition comprising: Gold salts; and a complexing agent, optionally further comprising a short chain carboxylic acid or a salt thereof; wherein the gold salt is a carboxylate or the gold salt is capable of forming a carboxylate with the short chain carboxylic acid or a salt thereof. (Item 2) 2. The ink composition according to claim 1, wherein the gold salt is a gold(I) salt, a gold(II) salt, or a gold(III) salt. (Item 3) 2. The ink composition according to item 1, wherein the gold salt is gold(III) formate, gold(III) acetate, gold(III) propionate, gold(III) lactate, gold(III) oxalate, gold(III) carbonate, gold(III) nitrate, gold(III) nitrite, gold(III) phosphate, gold(III) oxide, gold(III) fluoride, gold(III) bromide, gold(I) chloride, gold(III) chloride, gold(III) chloride trihydrate, gold(III) hydroxide, gold(I) iodide, tetrabromoauric(III) acid hydrate, potassium gold(III) chloride, or gold(III) terephthalate. (Item 4) 2. The ink composition according to claim 1, wherein the gold salt is a gold carboxylate. (Item 5) 2. The ink composition of claim 1, wherein the molar ratio of complexing agent to the gold salt is approximately 6:1. (Item 6) 2. The ink composition according to claim 1, wherein the complexing agent is an alkylamine or ammonia. (Item 7) 7. The ink composition according to claim 6, wherein the alkylamine is a primary amine, a secondary amine, or a polyamine. (Item 8) 7. The ink composition according to claim 6, wherein the alkylamine is selected from the group consisting of methylamine, dimethylamine, ethylamine, diethylamine, propylamine, dipropylamine, butylamine, dibutylamine, amylamine, isoamylamine, dipentylamine, and combinations thereof. (Item 9) 2. The ink composition according to claim 1, wherein the short chain carboxylic acid is selected from the group consisting of formic acid, acetic acid, propionic acid, lactic acid, oxalic acid, citric acid, and citraconic acid. (Item 10) Item 2. The ink composition of item 1, further comprising methylenediamine or ethylenediamine. (Item 11) Item 1. The ink composition of item 1, further comprising a solvent selected from the group consisting of ethanol, butanol, propylene glycol, water, and combinations thereof. (Item 12) the gold salt is gold(III) formate, and The complexing agent is selected from the group consisting of methylamine, dimethylamine, ethylamine, diethylamine, propylamine, dipropylamine, butylamine, dibutylamine, amylamine, dipentylamine, ammonia, and combinations thereof; Item 2. The ink composition according to item 1. (Item 13) the complexing agent is selected from the group consisting of methylamine, dimethylamine, ethylamine, diethylamine, propylamine, dipropylamine, butylamine, dibutylamine, amylamine, dipentylamine, ammonia, and combinations thereof; and The short chain carboxylic acid is acetic acid. Item 2. The ink composition according to item 1. (Item 14) Item 14. The ink composition according to item 13, further comprising ethylenediamine. (Item 15) Item 14. The ink composition according to item 13, further comprising a solvent selected from the group consisting of ethanol, butanol, propylene glycol, water, and combinations thereof. (Item 16) 1. An ink composition for producing a conductive structure comprising gold, the ink composition comprising: Gold salts of organic acids; Monomer building blocks; and A solvent having a boiling point of about 160° C. or lower; wherein a conjugate base of the organic acid reacts with the monomer component to form a polymer during which ionic gold is reduced to elemental gold. (Item 17) 17. The ink composition according to claim 16, wherein the polymer is a polyamide, a polyimide, a polyamideimide, or a polyester. (Item 18) Item 17. The ink composition according to item 16, wherein the organic acid comprises a dicarboxylic acid selected from the group consisting of oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, hexadecanedioic acid, and terephthalic acid. (Item 19) Item 17. The ink composition of item 16, wherein the monomer component comprises a diamine, an N-silylated diamine, or a diisocyanate. (Item 20) 20. The ink composition of claim 19, wherein the diamine comprises a linear aliphatic diamine, a branched aliphatic diamine, a cycloaliphatic diamine, or an aromatic diamine. (Item 21) The monomeric building blocks are selected from the group consisting of ethylenediamine, N-alkylated diamines, 1,1-dimethylethylenediamine, 1,1-dimethylethylenediamine, tetramethylethylenediamine, ethambutol, TMEDA, 1,3-diaminopropane, putrescine, cadaverine, or hexamethylenediamine, ethylenediamine, 1,2-diaminopropane, diphenylethylenediamine, trans-1,2-diaminocyclohexane, 1,4-diazacycloheptane, o-xylylenediamine, m-xylylenediamine, p-xylylenediamine, o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 2,5-diaminotoluene, N-methylated derivatives of phenylenediamine, dimethyl- 20. The ink composition according to item 19, wherein the diamine having two aromatic rings is selected from the group consisting of 4-phenylenediamine, N,N'-di-2-butyl-1,4-phenylenediamine, diamines having two aromatic rings, 4,4'-diaminobiphenyl or 1,8-diaminonaphthalene, toluene diisocyanate, methylene diphenyl diisocyanate, hexamethylene diisocyanate, methyl isocyanate, and isophorone diisocyanate. (Item 22) Item 17. The ink composition of item 16, wherein the polymer is a polyimide formed from a poly(amic acid) precursor, a polyisoimide precursor, a mixture of diester-acids and diamines, a mixture of tetracarboxylic acids and diamines, a mixture of dianhydrides and diisocyanates, a polyetherimide via a nucleophilic aromatic substitution reaction, or a mixture of 4,4'-methylenediphenyldiisocyanate and trimellitic anhydride. (Item 23) Item 18. The ink composition according to item 17, wherein the polyester is selected from the group consisting of polyethylene adipate, polybutylene succinate, poly(3-hydroxybutyrate-co-3-hydroxyvalerate), polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, and Vectran. (Item 24) 1. A method of making a conductive structure comprising gold, the method comprising: providing a metal salt composition comprising a gold salt and a complexing agent; adding a short chain carboxylic acid or salt thereof to the combined metal salt composition and complexing agent to form an ink composition; Optionally, partially evaporating the complexing agent from the ink composition to form a concentrated formulation; and reducing the metal salt composition to form a conductive structure comprising gold; wherein the concentrated formulation and the gold-containing conductive structure are formed at a temperature of about 160° C. or less. (Item 25) 25. The method of claim 24, wherein the temperature is about 140° C. or lower. (Item 26) 25. The method of claim 24, wherein the short chain carboxylic acid or salt of the short chain carboxylic acid is not added until after the gold salt has dissolved in the complexing agent. (Item 27) 25. The method of claim 24, further comprising depositing the ink composition on a substrate. (Item 28) 28. The method of claim 27, wherein the ink composition is deposited on the substrate by a method selected from the group consisting of spraying, dip coating, spin coating, ink jet printing, and e-jet printing. (Item 29) 25. The method of claim 24, further comprising depositing the concentrated formulation onto a substrate. (Item 30) 30. The method of claim 29, wherein the concentrated formulation is deposited on the substrate by a method selected from the group consisting of screen printing, roll-to-roll processing, and direct ink writing. (Item 31) 1. A method of making a conductive structure comprising gold, the method comprising: Providing a gold salt of an organic acid and a monomer building block; and causing polymer formation between the conjugate base of the organic acid and the monomer building blocks; The method includes:

Claims

1. An ink composition for producing conductive gold structures, the ink composition comprising: Gold salts; and a complexing agent, optionally further comprising a short chain carboxylic acid or a salt thereof; Including, wherein the gold salt is gold(III) formate, gold(III) acetate, gold(III) propionate, gold(III) lactate, gold(III) oxalate, or a mixture thereof; and wherein the complexing agent is an alkylamine or ammonia. Ink composition.

2. The ink composition described in claim 1, wherein the molar ratio of complexing agent to the gold salt is 6:

1.

3. The ink composition described in claim 2, wherein the alkylamine is a primary amine, a secondary amine, or a polyamine.

4. The ink composition described in claim 2, wherein the alkylamine is selected from the group consisting of methylamine, dimethylamine, ethylamine, diethylamine, propylamine, dipropylamine, butylamine, dibutylamine, amylamine, isoamylamine, dipentylamine, and combinations thereof.

5. The ink composition of claim 1, wherein the short chain carboxylic acid is selected from the group consisting of formic acid, acetic acid, propionic acid, lactic acid, oxalic acid, citric acid, and citraconic acid.

6. The ink composition of claim 1, further comprising methylenediamine or ethylenediamine.

7. The ink composition of claim 1, further comprising a solvent selected from the group consisting of ethanol, butanol, propylene glycol, water, and combinations thereof.

8. The gold salt is gold(III) formate, and The complexing agent is selected from the group consisting of methylamine, dimethylamine, ethylamine, diethylamine, propylamine, dipropylamine, butylamine, dibutylamine, amylamine, dipentylamine, ammonia, and combinations thereof; The ink composition according to claim 1 .

9. The complexing agent is selected from the group consisting of methylamine, dimethylamine, ethylamine, diethylamine, propylamine, dipropylamine, butylamine, dibutylamine, amylamine, dipentylamine, ammonia, and combinations thereof; and The short chain carboxylic acid is acetic acid. The ink composition according to claim 1 .

10. The ink composition of claim 9, further comprising ethylenediamine.

11. The ink composition of claim 9, further comprising a solvent selected from the group consisting of ethanol, butanol, propylene glycol, water, and combinations thereof.

12. An ink composition for producing a conductive structure comprising gold, the ink composition comprising: Gold salts of organic acids; Monomer building blocks; and A solvent having a boiling point of 160° C. or lower; Including, wherein the gold salt is a gold(III) salt; wherein the organic acid is oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, hexadecanedioic acid, or terephthalic acid; An ink composition wherein a conjugate base of said organic acid reacts with said monomeric building blocks to form a polymer during which ionic gold is reduced to elemental gold.

13. The ink composition of claim 12, wherein the polymer is a polyamide, a polyimide, a polyamideimide, or a polyester.

14. The ink composition of claim 12, wherein the monomeric component comprises a diamine, an N-silylated diamine, or a diisocyanate.

15. The ink composition of claim 14, wherein the diamine comprises a linear aliphatic diamine, a branched aliphatic diamine, a cyclic aliphatic diamine, or an aromatic diamine.

16. The monomeric building blocks are selected from the group consisting of ethylenediamine, N-alkylated diamines, 1,1-dimethylethylenediamine, 1,1-dimethylethylenediamine, tetramethylethylenediamine, ethambutol, TMEDA, 1,3-diaminopropane, putrescine, cadaverine, or hexamethylenediamine, ethylenediamine, 1,2-diaminopropane, diphenylethylenediamine, trans-1,2-diaminocyclohexane, 1,4-diazacycloheptane, o-xylylenediamine, m-xylylenediamine, p-xylylenediamine, o-phenylenediamine.

15. The ink composition of claim 14, wherein the diisocyanate is selected from the group consisting of N,N'-di-2-butyl-1,4-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 2,5-diaminotoluene, N-methylated derivatives of phenylenediamine, dimethyl-4-phenylenediamine, N,N'-di-2-butyl-1,4-phenylenediamine, diamines having two aromatic rings, 4,4'-diaminobiphenyl or 1,8-diaminonaphthalene, toluene diisocyanate, methylene diphenyl diisocyanate, hexamethylene diisocyanate, methyl isocyanate, and isophorone diisocyanate.

17. The ink composition of claim 12, wherein the polymer is a polyimide formed from a poly(amic acid) precursor, a polyisoimide precursor, a mixture of diester-acids and diamines, a mixture of tetracarboxylic acids and diamines, a mixture of dianhydrides and diisocyanates, a polyetherimide via a nucleophilic aromatic substitution reaction, or a mixture of 4,4'-methylenediphenyldiisocyanate and trimellitic anhydride.

18. The ink composition of claim 13, wherein the polyester is selected from the group consisting of polyethylene adipate, polybutylene succinate, poly(3-hydroxybutyrate-co-3-hydroxyvalerate), polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, and vectran.

19. A method of making a conductive structure comprising gold, the method comprising: providing a metal salt composition comprising a gold salt and a complexing agent; adding a short chain carboxylic acid or salt thereof to the combined metal salt composition and complexing agent to form an ink composition; Optionally, partially evaporating the complexing agent from the ink composition to form a concentrated formulation; and reducing the metal salt composition to form a conductive structure comprising gold; Inclusive of wherein the gold salt is gold(III) formate, gold(III) acetate, gold(III) propionate, gold(III) lactate, gold(III) oxalate, or a mixture thereof; wherein the complexing agent is an alkylamine or ammonia; and A method wherein said concentrated formulation and said gold-containing conductive structure are formed at a temperature of 160° C. or less.

20. The method of claim 19, wherein the temperature is 140°C or lower.

21. The method of claim 19, wherein the short chain carboxylic acid or salt of the short chain carboxylic acid is not added until after the gold salt has dissolved in the complexing agent.

22. The method of claim 19, further comprising depositing the ink composition on a substrate.

23. The method of claim 22, wherein the ink composition is deposited on the substrate by a method selected from the group consisting of spraying, dip coating, spin coating, inkjet printing, and e-jet printing.

24. The method of claim 19, further comprising depositing the concentrated formulation onto a substrate.

25. The method of claim 24, wherein the concentrated formulation is deposited on the substrate by a method selected from the group consisting of screen printing, roll-to-roll processing, and direct ink writing.

26. A method of making a conductive structure comprising gold, the method comprising: Providing a gold salt of an organic acid and a monomer building block; and causing polymer formation between the conjugate base of the organic acid and the monomer building blocks; Inclusive of wherein the gold salt is a gold(III) salt; wherein the organic acid is oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, hexadecanedioic acid, or terephthalic acid; method.