Improved conductive ink composition

Abstract

Improved conductive ink compositions and methods of making and using the conductive ink compositions are provided. The improved conductive ink compositions include a silver complex formed by mixing a silver carboxylate, specifically a silver decanoate isomer, and at least one solubilizing agent, where the at least one solubilizing agent includes a terpene, a terpenoid, or a combination thereof. The silver carboxylate of the subject ink compositions is decarboxylated at a temperature of 250°C or less. The conductive ink compositions preferably further include a non-acid stabilizer, and optionally further include an acid stabilizer and / or an adhesion promoter. Methods of making conductive structures are also provided, including methods in which the compositions of the present disclosure are applied to a suitable substrate by various techniques.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Patent Application No. 63 / 477,806, filed December 29, 2022, the disclosure of which is incorporated herein by reference in its entirety.

[0002] FIELD OF THE INVENTION The present disclosure relates generally to novel ink compositions and methods of their preparation and use. More particularly, the present disclosure relates to improved ink compositions that include silver carboxylates and are particle-free, forming conductive structures at low temperatures. [Background technology]

[0003] Background of the Invention The electronics, display, and energy industries rely on the production and use of coatings and patterns of conductive materials to form circuits on organic and inorganic substrates. Printed electronics offers an attractive alternative to conventional technologies by enabling the creation of low-cost, large-area, flexible devices. There is a great need for highly conductive materials with fine-scale features in modern electronics, such as solar cell electrodes, flexible displays, radio frequency identification tags, antennas, and many others. In an effort to make these high-technology devices more accessible, the substrates used typically have relatively low temperature resilience and require low processing temperatures to maintain their integrity.

[0004] The majority of commercially produced conductive inks are specifically designed for inkjet, screen printing, or roll-to-roll processing methods to process large areas with fine-scale features in a short time. These inks have completely different viscosity and composition parameters. Particle-based inks are based on conductive metal particles, which are typically synthesized separately and then incorporated into the ink formulation. The resulting ink is then tailored for the specific particle processing.

[0005] Typically, precursor-based inks are based on thermally unstable precursor complexes that undergo reduction to conductive metals upon heating. Conventional particle- and precursor-based methods generally rely on high temperatures to form conductive coatings and therefore may be incompatible with substrates that require low processing temperatures to maintain their integrity. For example, silver compounds containing carbamates or other relatively low-molecular-weight ligands (compared to polymer stabilizers) have been synthesized that decompose at temperatures around 150°C, resulting in electrical conductivities approaching those of bulk silver. Unfortunately, even at these temperatures, the inks can be incompatible with many plastic and paper substrates commonly used in flexible electronics and biomedical devices.

[0006] International Publication No. WO 2015 / 160938 provides conductive ink compositions, methods of manufacture and use, and conductive structures prepared using the ink compositions. Some ink compositions include a silver carboxylate, at least one solubilizer, and a catalyst that decarboxylates the silver carboxylate to form conductive structures. The decarboxylation reaction can occur at low temperatures.

[0007] European Patent No. EP3597707B1 provides a conductive ink composition for inkjet or screen printing processes. The conductive ink composition comprises a silver carboxylate, a terpene, and at least one carboxylic acid as a further component. The ink composition can be used in a method for producing a pattern on a substrate. International Publication Nos. WO2015 / 192248A1 and WO2018 / 146617A1 provide conductive ink compositions containing a silver carboxylate, a solvent, and a polymer binder.

[0008] Despite these and other advances in the field, a need continues to exist for particle-free conductive ink compositions with improved properties. Accordingly, it is an object of the present invention to provide improved particle-free, stable conductive ink compositions and methods for their preparation and use, particularly compositions that can form conductive structures at low temperatures, ideally without a catalyst. It is also an object of the present invention to provide improved particle-free, stable conductive ink compositions and methods for their preparation and use, where the compositions have reasonable adhesion to a variety of substrates for a variety of purposes. Such purposes may include those related to inkjet printing epoxy molding compounds (EMCs) with both thin and thick layers, solder resist functionality, silver nanowire substrates (SNWs), and the like. Such conductive inks can be used on a variety of substrates to form conductive structures with excellent physical, mechanical, and electrical properties. It is a further object of the present invention to provide improved conductive ink compositions that are particle-free and stable, and methods for their preparation and use, wherein the compositions have improved stability even in the absence of an acid stabilizer. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] International Publication No. 2015 / 160938 [Patent Document 2] European Patent No. 3597707 [Patent Document 3] International Publication No. 2015 / 192248 [Patent Document 4] International Publication No. 2018 / 146617 Summary of the Invention

[0010] Summary of the Invention The present disclosure addresses these and other considerations by providing, in one aspect, a conductive ink composition comprising a silver complex formed by combining silver decanoate, at least one solubilizer, and a stabilizer, wherein the silver decanoate is decarboxylated at a temperature at or below 250° C. to form conductive structures.

[0011] In some embodiments, the technology described herein relates to a conductive ink composition comprising silver decanoate, at least one solubilizing agent, and at least one non-acid stabilizer, wherein the at least one solubilizing agent comprises a terpene, a terpenoid, or a combination thereof, and wherein the silver decanoate is decarboxylated at a temperature of 250° C. or less to form a conductive structure.

[0012] In some aspects, the technology described herein relates to a method of making a conductive structure, the method comprising dissolving silver decanoate in at least one solubilizing agent to form a conductive ink composition, wherein the at least one solubilizing agent comprises a terpene, a terpenoid, or a combination thereof, and the conductive ink composition further comprises at least one non-acid stabilizer.

[0013] In some aspects, the technology described herein relates to a method of making a conductive ink composition comprising dissolving silver decanoate in at least one solubilizing agent to form a conductive ink composition, wherein the at least one solubilizing agent comprises a terpene, a terpenoid, or a combination thereof, and wherein the conductive ink composition further comprises at least one non-acid stabilizer. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 shows the stability of exemplary ink composition formulations of the present disclosure.

[0015] [Figure 2] FIG. 2 shows the stability of exemplary ink composition formulations of the present disclosure.

[0016] [Figure 3] FIG. 3 shows the stability of exemplary ink composition formulations of the present disclosure.

[0017] [Figure 4] FIG. 4 shows the stability of exemplary ink composition formulations of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0018] Detailed Description of the Invention Ink compositions derived from silver metal precursors are described in PCT International Publication No. WO 2013 / 096664 A1, which is incorporated herein by reference in its entirety. Additional conductive ink compositions are described, for example, in PCT International Publication No. WO 2015 / 160938 A1, which is also incorporated herein by reference in its entirety. These ink compositions advantageously do not contain metal particles but typically require a catalyst, such as an amine-containing catalyst, to promote decarboxylation of the silver complexes at low temperatures, thereby forming conductive metal structures.

[0019] Other improved conductive ink compositions are described in U.S. Patent Application Nos. 63 / 316,949, filed March 4, 2022, 63 / 370,343, filed August 3, 2022, and 63 / 384,202, filed November 17, 2022, each of which is incorporated herein by reference in its entirety. These ink compositions include silver decanoate and at least one solubilizing agent. In some embodiments, the ink composition includes at least one α-branched silver decanoate isomer. In some embodiments, the ink composition includes an adhesion promoter including a reactive silane or an epoxide. In preferred embodiments, the improved conductive ink composition does not require a catalyst to decarboxylate the silver complex.

[0020] Disclosed herein is an improved conductive ink composition comprising silver decanoate and at least one solubilizing agent, which forms conductive metal structures at low temperatures. The composition preferably further comprises a stabilizer, preferably a non-acid stabilizer, such as a β-diketone stabilizer. The stabilizer in the present composition is preferably soluble in the ink composition and can increase the metal loading, for example, by about 0.5% to about 3%, without reducing the conductivity of conductive metal structures formed from the ink composition at low temperatures on various substrates. Furthermore, the ink composition containing the stabilizer is stable at 30°C and even 40°C without visible precipitation / plating for extended periods, and the viscosity of the ink composition is suitable for use with standard inkjet printheads, including Samba and Ricoh printheads. By using a lower decomposition temperature and a shortened tack time to form conductive structures, the improved conductive ink composition is compatible with more substrates that do not require high processing temperatures to maintain their integrity. Furthermore, the method for making the conductive ink composition is simple and produces a high yield of conductive structures.

[0021] The conductive ink composition can have a low viscosity, making it compatible with a wide range of patterning techniques, including slot-die coating, spin coating, and roll-to-roll printing, including gravure, flexography, rotary screen printing, screen printing, aerosol jet printing, inkjet printing, airbrushing, Mayer rod coating, flood coating, 3D printing, and electrohydrodynamic printing. In particular, the ink is compatible with inkjet printing, dip coating, and spray coating. The patterned features can be highly conductive at room temperature and can achieve bulk conductivity upon decomposition at moderate temperatures (e.g., below about 100°C in some cases). Finally, the ink composition can remain stable at room temperature for several months without particle precipitation.

[0022] Thus, conductive ink compositions (also referred to as "conductive inks" or "inks") have been created for printing highly conductive features at low temperatures. Such inks are stable, particle-free, and can be suitable for a wide range of patterning techniques. In some embodiments, a "particle-free" ink is an ink that does not contain any particles greater than about 10 nm in diameter. In some embodiments, a "particle-free" ink is an ink that has less than about 1% particles, preferably less than about 0.1% particles. A silver salt is used in the ink as a precursor material, which ultimately yields silver in a conductive silver coating, line, or pattern. Any suitable silver precursor may be used.

[0023] In one aspect, the conductive ink composition includes a silver complex formed by mixing a silver carboxylate and at least one solubilizing agent. In a preferred embodiment, the silver carboxylate is soluble in the solubilizing agent. Solubility, as known to those skilled in the art, is the property of a substance, such as a silver carboxylate, to dissolve in a solvent, such as a solubilizing agent. In some embodiments, the silver complex is first applied to a substrate. In some embodiments, the silver carboxylate is converted to a conductive silver structure at a temperature of about 250°C or less. In some embodiments, the silver carboxylate is converted to a conductive silver structure at a temperature of about 100°C or less. In some embodiments, the silver carboxylate is converted to the conductive silver structure at a temperature of about 220°C, about 210°C or less, about 190°C or less, about 180°C or less, about 170°C or less, about 160°C or less, about 150°C or less, about 140°C or less, about 130°C or less, about 120°C or less, about 110°C or less, about 90°C or less, about 80°C or less, about 70°C or less, about 60°C or less, or about 50°C or less.

[0024] Silver carboxylate The silver carboxylate of the present conductive ink composition comprises a silver salt of an aliphatic carboxylic acid. In some embodiments, the silver carboxylate comprises a silver salt of a long-chain aliphatic carboxylic acid. In specific embodiments, the silver carboxylate comprises a silver salt of a long-chain aliphatic carboxylic acid having 5 to 15 carbon atoms, 8 to 12 carbon atoms, or even 9 to 11 carbon atoms.

[0025] In preferred embodiments, the silver carboxylate of the present composition comprises silver decanoate, or, in particular, a silver decanoate isomer or a mixture of silver decanoate isomers. For example, in some embodiments, at least one decanoic acid isomer used to form the silver decanoate of the conductive ink composition has the following structure: [ka] wherein R1 and R2 are each independently an alkyl group, R3 is either hydrogen or an alkyl group, and R1, R2, and R3 collectively contain a total of 8 carbon atoms. Thus, silver decanoate formed from the above decanoic acid isomers has the following structure: [ka] where the R, R, and R groups have the definitions provided above. Such structures are referred to herein as α-branched silver decanoate isomers.

[0026] In some embodiments, the R1 and R2 groups of the α-branched silver decanoate isomer are each independently methyl or ethyl.

[0027] In specific embodiments, the at least one decanoic acid isomer used to form the silver decanoate of the present conductive ink composition can be, for example, 2,2-dimethyloctanoic acid, 2,2,3,5-tetramethylhexanoic acid, 2,4-dimethyl-2-isopropylpentanoic acid, 2,5-dimethyl-2-ethylhexanoic acid, 2,2-diethylhexanoic acid, 2-butylhexanoic acid, or any combination of these α-branched decanoic acid isomers.

[0028] The corresponding silver carboxylates can be formed from each of these decanoic acid isomers, as described in the Examples section and as would be understood by one of ordinary skill in the art. Specifically, the silver decanoate isomer can be, for example, an α-branched silver decanoate isomer, such as silver 2,2-dimethyloctanoate, silver 2,2,3,5-tetramethylhexanoate, silver 2,4-dimethyl-2-isopropylpentanoate, silver 2,5-dimethyl-2-ethylhexanoate, silver 2,2-diethylhexanoate, silver 2-butylhexanoate, or any combination of these compounds.

[0029] The silver carboxylate is preferably not formed from a straight chain alkanoic acid, for example, the silver carboxylate is preferably not formed from n-decanoic acid.

[0030] In embodiments, about 0.4 grams to about 1.0 grams of silver carboxylate, specifically silver decanoate containing at least one α-branched silver decanoate isomer, is dissolved per gram of solubilizing agent. In some embodiments, about 0.4 grams, about 0.5 grams, about 0.6 grams, about 0.7 grams, about 0.8 grams, about 0.9 grams, or even about 1.0 grams of silver carboxylate, specifically at least one or more α-branched silver decanoate isomers, is dissolved per gram of solubilizing agent.

[0031] solubilizer As described above, the present conductive ink composition includes at least one solubilizing agent capable of dissolving the silver carboxylate of the present disclosure, preferably completely dissolving the silver carboxylate, to produce a particle-free conductive ink composition. Specifically, the solubilizing agent acts as a stabilizer and solvent, but is not intended to act as a reducing agent for the silver carboxylate. In some embodiments, the solubilizing agent has a boiling point of about 250°C or less. In some embodiments, the solubilizing agent has a boiling point of about 200°C or less. In some embodiments, the solubilizing agent has a boiling point of about 100°C or less. In some embodiments, the lysing agent has a boiling point of about 220°C or less, about 210°C or less, about 190°C or less, about 180°C or less, about 170°C or less, about 160°C or less, about 150°C or less, about 140°C or less, about 130°C or less, about 120°C or less, about 110°C or less, about 90°C or less, about 80°C or less, about 70°C or less, about 60°C or less, or about 50°C or less.

[0032] In some embodiments, the solubilizer may be selected based on the type of silver carboxylate used to make the ink composition. In some embodiments, the solubilizer may be selected based on the boiling point / tack time of the specific application. In some embodiments, the solubilizer may be selected based on the type of substrate to which the ink composition will be applied, with regard to compatibility and wetting issues. For example, for deposition methods such as inkjet printing or e-jet, higher stability is generally preferred, and therefore, it may be preferable to use a solubilizer with a higher boiling point.

[0033] In some embodiments, the lysing agent comprises an alkane hydrocarbon, a carbamate, an alkene, a cyclic hydrocarbon, an aromatic hydrocarbon, an amine, a polyamine, an amide, an ether, an ester, an alcohol, a thiol, a thioether, a phosphine, or a combination thereof.

[0034] In some embodiments, the dissolution agent comprises an organic solvent. 5~20 For example, the solubilizing agent can include pentane, hexane, heptane, octane, nonane, decane, undecane, dodecane, tridecane, tetradecane, pentadecane, hexadecane, octadecane, nonadecane, or icosane.

[0035] In some embodiments, the lytic agent is C 6~10 The solubilizing agent may comprise one or more cyclic hydrocarbons having a length of 0.05 to 0.05 mm. For example, the solubilizing agent may comprise cyclohexane, cycloheptane, cyclooctane, cyclononane, cyclodecane, or decalin. In some embodiments, the solubilizing agent comprises an aromatic hydrocarbon. For example, the solubilizing agent may comprise benzene, toluene, xylene, or tetralin. In some embodiments, the solubilizing agent comprises xylene.

[0036] In some embodiments, the solubilizing agent comprises a linear ether, a branched ether, or a cyclic ether. In some embodiments, the solubilizing agent comprises a linear or branched ether. For example, the solubilizing agent may comprise dimethyl ether, diethyl ether, dipropyl ether, dibutyl ether, or methyl t-butyl ether. In some embodiments, the solubilizing agent comprises one or more cyclic ethers. For example, the solubilizing agent may comprise tetrahydrofuran, tetrahydropyran, dihydropyran, or 1,4-dioxane.

[0037] In some embodiments, the dissolving agent comprises an alcohol. In some embodiments, the dissolving agent comprises a primary alcohol, a secondary alcohol, or a tertiary alcohol. In some embodiments, the alcohol comprises propanol, butanol, pentanol, hexanol, octanol, or a combination thereof. In some embodiments, the alcohol comprises 1-propanol, 2-propanol, 1-methoxy-2-propanol, 1-butanol, 2-butanol, 1-pentanol, 2-pentanol, 3-pentanol, 1-hexanol, 2-hexanol, 3-hexanol, 1-octanol, 2-octanol, 3-octanol, tetrahydrofurfuryl alcohol, cyclopentanol, terpineol, or a combination thereof.

[0038] In some embodiments, the lysis agent comprises a ketone. More specifically, in some embodiments, the lysis agent comprises actylacetone.

[0039] The solubilizers used in the present conductive ink compositions are ideally suited for use in industrial-scale mass production. Therefore, in some embodiments, it may be advantageous for the solubilizer to be non-toxic and / or less damaging to the environment than many commonly used organic solvents. In some embodiments, it may be advantageous for the solubilizer to have a higher flash point than many commonly used organic solvents. In some embodiments, it may be advantageous for the solubilizer to be subject to fewer regulations than many commonly used organic solvents. For example, aromatic hydrocarbons such as xylene, toluene, and mesitylene are highly regulated in most industrialized countries. Therefore, the use of alternatives to these solvents may be advantageous. Additionally, conductive inks formulated from aromatic hydrocarbons may have flash points below 60°C and therefore are typically unacceptable in mass production environments. Therefore, in some embodiments, the solubilizers of the present conductive ink compositions are free of aromatic hydrocarbons.

[0040] In preferred embodiments, the solubilizing agent comprises a terpene, a terpenoid, or a combination thereof. For example, in some embodiments, the solubilizing agent comprises pinene, limonene, particularly D-limonene, terpineol, or a combination thereof. In preferred embodiments, the solubilizing agent comprises limonene. In other preferred embodiments, the solubilizing agent comprises terpineol. In yet other preferred embodiments, the solubilizing agent comprises a combination of limonene and terpineol.

[0041] Not all terpenes and terpenoids are suitable for use in the conductive ink compositions of the present disclosure. For example, in some embodiments, the solubilizer does not include alpha-terpinene, gamma-terpinene, terpinolene, or terpene-4-ol. Alternatively or additionally, in some embodiments, it may be advantageous for the solubilizer to be a purified form of the solubilizer. For example, in some embodiments, the solubilizer is purified terpineol, purified limonene, or a combination of purified terpineol and purified limonene. A purified solubilizer is understood to be at least 95% pure, at least 97% pure, at least 98% pure, at least 99% pure, or even more pure.

[0042] In some embodiments, the solubilizer is added in an amount such that the silver carboxylate is substantially or completely dissolved in the solubilizer. In some embodiments, "substantially soluble" means that the silver carboxylate has a solubility in the solubilizer at 25° C. of at least about 200 g / L, at least about 300 g / L, at least about 400 g / L, or even higher. In embodiments in which the silver carboxylate is substantially or completely dissolved in the solubilizer, the conductive ink composition can be considered particle-free.

[0043] In some embodiments, the conductive ink composition comprises two or more solubilizing agents. In some embodiments, the volume ratio of the two solubilizing agents in the conductive ink is about 1 to about 1 for the first solubilizing agent to the second solubilizing agent. In some embodiments, the volume ratio of the two solubilizing agents in the conductive ink is about 2 to about 1 for the first solubilizing agent to the second solubilizing agent. In some embodiments, the volume ratio of the two solubilizing agents is about 3 to about 1 for the first solubilizing agent to the second solubilizing agent. In some embodiments, the volume ratio of the two solubilizing agents is about 4 to about 1 for the first solubilizing agent to the second solubilizing agent.

[0044] In some embodiments, the flash point of the conductive ink composition may be altered by changing the volume ratio of two or more solvents in the conductive ink. For example, in some embodiments, the flash point of the conductive ink composition may be increased by increasing the relative amount of a solvent having a higher flash point compared to a solvent having a lower flash point. More specifically, in some embodiments, the flash point of the conductive ink composition may be adjusted by changing the ratio of limonene to terpineol in the conductive ink composition. Even more specifically, the flash point of the conductive ink composition may be decreased by increasing the ratio of limonene to terpineol in the conductive ink composition.

[0045] Acid stabilizer In another aspect, a conductive ink composition is provided that further comprises an organic acid to stabilize the ink composition. It should be understood that even if no additional organic acid is added to the formulation, residual organic acid may remain present at low levels in the silver carboxylate of the present conductive ink composition (e.g., the silver decanoate preparation described below), but in some cases, it may be advantageous to add an acid stabilizer to the conductive ink formulation of the present disclosure. For example, the presence of an acid stabilizer in the conductive ink formulation may increase the stability of the formulation, particularly during storage at elevated temperatures (e.g., 30°C or 40°C). Without intending to be bound by theory, it is believed that the presence of an acid stabilizer in these formulations inhibits the formation of metallic silver during storage.

[0046] In some embodiments, the added acid stabilizer is C 6~12 The acid stabilizer is an α-branched alkanoic acid. In a preferred embodiment, the added acid stabilizer is one or more of the decanoic acid isomers used to produce the silver decanoate of the conductive ink composition. For example, the added acid stabilizer can be an α-branched decanoic acid isomer. In another preferred embodiment, the added acid stabilizer is 2,2-dimethylhexanoic acid or 2,2-dimethylnonanoic acid.

[0047] The added acid stabilizer is preferably not a linear alkanoic acid. For example, the added acid stabilizer is preferably not n-heptanoic acid, n-octanoic acid, or n-decanoic acid. The added acid stabilizer is also preferably not a secondary alkanoic acid, such as 2-butylhexanoic acid.

[0048] The added acid stabilizer is preferably included in the conductive ink composition in an amount ranging from 0 to 15 wt %, hi some embodiments, the added acid stabilizer is included at about 0.5 wt %, about 1.5 wt %, about 5 wt %, about 10 wt %, or even about 15 wt %.

[0049] Non-acid stabilizer In another aspect, a conductive ink composition is provided that includes a non-acid stabilizer to stabilize the ink composition, which can be used in addition to or as a replacement for any of the acid stabilizers described above.

[0050] In some embodiments, the non-acid stabilizer is a β-diketone.

[0051] In some embodiments, the β-diketone has the structure of formula (I): [ka] wherein each R group is independently a C1-C6 straight or branched chain alkyl group optionally substituted with an aryl group, or an aryl group; each R group is independently -H, a C1-C6 straight or branched chain alkyl group optionally substituted with an aryl group; or two R groups together form a double bond optionally substituted with a C1-C6 straight or branched chain alkyl group optionally further substituted with an aryl group, or a double bond optionally substituted with an aryl group.

[0052] In some embodiments, the R4 and R5 groups of formula (I) are independently substituted with an alkoxy, hydroxy, thio, amino, halo, cyano, or nitro group.

[0053] In more specific embodiments, each R4 group is independently a C1-C4 straight or branched chain alkyl group optionally substituted with a phenyl group, or a phenyl group; each R5 group is independently -H, a C1-C4 straight or branched chain alkyl group optionally substituted with a phenyl group; or two R5 groups together form a double bond optionally substituted with a C1-C4 straight or branched chain alkyl group optionally further substituted with a phenyl group, or a double bond optionally substituted with a phenyl group.

[0054] In even more specific embodiments, each R group is independently methyl, ethyl, or phenyl; each R group is independently hydrogen, methyl, ethyl, or benzyl; or two R groups together form a double bond optionally substituted with a methyl, ethyl, or phenyl group.

[0055] In even more specific embodiments, the β-diketone is one of the following compounds: [ka]

[0056] In some embodiments, the conductive ink formulation includes more than one of the above compounds.

[0057] Adhesion promoter In another aspect, there is provided a conductive ink composition further comprising an adhesion promoter that increases the adhesion of the ink to a substrate onto which the ink is printed. It is contemplated that any agent that improves the adhesive properties of the ink and does not significantly impair the fluid or other physical properties of the ink composition, including its stability, or the electrical or other physical properties of the conductive structures produced using the ink can be utilized as an adhesion promoter in the present ink composition.

[0058] It should be understood that the adhesion promoter and the acid or β-diketone stabilizer may each be included in the conductive ink composition in any combination, either together or separately.

[0059] The adhesion promoter is preferably selected consistent with the choice of substrate onto which the ink will be printed.

[0060] In some embodiments, the adhesion promoter comprises a reactive silane. Reactive silanes are known in the chemical and material science fields to enhance the performance of coatings. For example, they can improve adhesion to inorganic substrates, cause crosslinking, improve dispersion of composition components, improve hydrophobicity, and trap moisture. In specific embodiments, the reactive silane comprises an alkoxysilane group, e.g., a trialkoxysilyl group. In some embodiments, the alkoxysilyl group can be oligomerized or polymerized into a number of different chain length configurations. In some embodiments, the adhesion promoter comprises an alkyl group, more specifically, an alkyl group comprising a second reactive moiety. For example, the adhesion promoter can comprise a polyalkene, e.g., poly-1,2-butadiene. Suitable adhesion promoters are commercially available, for example, from Gelest, Inc., Morrisville, PA, USA.

[0061] In some embodiments, the adhesion promoter comprises an epoxy group. More specifically, the adhesion promoter can comprise an epoxy group coupled to a silane, such as any of the reactive silanes described above. In some embodiments, the adhesion promoter can comprise an epoxy group coupled to an alkoxysilane group, such as a trialkoxysilyl group. In specific embodiments, the adhesion promoter can comprise an epoxy group coupled to a trialkoxysilyl group, such as a trimethoxysilyl group or a triethoxysilyl group.

[0062] The adhesion promoter preferably includes a linker group that couples the reactive silane group with a second reactive group, e.g., an alkyl group containing a reactive moiety such as a polyalkene or epoxy group. The linker group can be any suitable chemical linker. In some embodiments, the linker group is an alkyl linker group, e.g., a C2-C 10 It is an alkyl linker group. In some embodiments, the linker group is a substituted alkyl linker group, in which the alkyl linker group is substituted with any suitable substituent. For example, the alkyl linker group may be substituted with one or more alkyl, alkenyl, alkynyl, alkoxy, alkanoyl, alkylamino, hydroxy, thio, amino, alkanoylamino, alkylcarboxy, carbonate, halo, nitro, cyano groups, etc. In some embodiments, one or more of the carbon atoms of the linker may be replaced with a suitable heteroatom. In specific embodiments, the heteroatom may be oxygen, sulfur, or nitrogen in any combination. More specifically, the heteroatom may be oxygen.

[0063] In some embodiments, the adhesion promoter has the structure shown in Formula (II): [ka] wherein each R' is independently a C1-C6 alkyl group and L' is an alkyl linker group. In more specific embodiments of structural formula (II), each R' is independently a methyl or ethyl group. In other more specific embodiments of structural formula (II), L' is a substituted C2-C10 C2-C containing alkyl linker groups 10 It may be an alkyl linker group. In some embodiments of Structural Formula (II), one or more of the carbon atoms of L' may be replaced with a suitable heteroatom, such as oxygen, sulfur, or nitrogen in any combination. More specifically, the heteroatom may be oxygen.

[0064] In some more specific embodiments, the adhesion promoter has the structure shown in formula (III): [ka] wherein each R' is independently a methyl or ethyl group, X is a heteroatom, and each n is independently 1 to 6. In some embodiments of Structural Formula (III), each R' is a methyl group, X is oxygen, and each n is independently 1 to 3.

[0065] In some specific embodiments, the adhesion promoter of the conductive ink composition is [ka] This compound is readily soluble in typical ink formulations. Specifically, ink formulations containing this adhesion promoter can be prepared at 0.1-0.5% without reducing the conductivity of structures produced from this ink on various substrates. Furthermore, inks containing this adhesion promoter are stable for 14-30 days at 40°C without visible precipitation or plating. These formulations also exhibit suitable viscosities for use in typical industrial inkjet printhead technology. The addition of up to 3% water to the ink formulation does not reduce the stability of these inks at 40°C.

[0066] In some specific embodiments, the adhesion promoter of the conductive ink composition is [ka] is.

[0067] Particle-free conductive ink composition Provided herein is a conductive ink composition comprising the above-described silver carboxylate. For example, in some embodiments, the silver carboxylate is silver decanoate, and the silver decanoate comprises at least one α-branched silver decanoate isomer as described above. In some embodiments, the at least one α-branched silver decanoate isomer is a silver salt of 2,2-dimethyloctanoic acid, 2,2,3,5-tetramethylhexanoic acid, 2,4-dimethyl-2-isopropylpentanoic acid, 2,5-dimethyl-2-ethylhexanoic acid, 2,2-diethylhexanoic acid, 2-butylhexanoic acid, or any combination of these α-branched decanoic acid isomers.

[0068] In some embodiments, the conductive ink composition does not contain a catalyst. In particular, when the silver carboxylate is silver decanoate, such as a silver decanoate containing at least one α-branched silver decanoate isomer or a mixture of various α-branched silver decanoate isomers, it may not be necessary to include a catalyst, even an amine-containing catalyst, in the composition. Thus, in these embodiments, the conductive structure can be formed from the conductive ink composition by heating the silver complex at a temperature of about 250° C. or less to form the conductive structure.

[0069] In some embodiments, the conductive ink composition has a silver concentration of from about 1 to about 50 percent by weight of the conductive ink composition. In some embodiments, the conductive ink composition has a silver concentration of from about 1 to about 40 percent by weight of the conductive ink composition. In some embodiments, the conductive ink composition has a silver concentration of from about 1 to about 30 percent by weight of the conductive ink composition. In some embodiments, the conductive ink composition has a silver concentration of from about 1 to about 20 percent by weight of the conductive ink composition. In some embodiments, the conductive ink composition has a silver concentration of from about 1 to about 10 percent by weight of the conductive ink composition. In some embodiments, the conductive ink composition has a silver concentration of from about 5 to about 15 percent by weight of the conductive ink composition. In some embodiments, the conductive ink composition may comprise about 1 weight percent, about 2 weight percent, about 3 weight percent, about 4 weight percent), about 5 weight percent, about 6 weight percent, about 7 weight percent, about 8 weight percent, about 9 weight percent, about 10 weight percent), about 11 weight percent), about 12 weight percent, about 13 weight percent, about 14 weight percent, about 15 weight percent, about 16 weight percent), about 17 weight percent), about 18 weight percent, about 19 weight percent, about 20 weight percent, about 21 weight percent, about 22 weight percent), about 23 weight percent, about 24 weight percent, about 25 weight percent in the conductive ink composition. about 26 weight percent, about 27 weight percent, about 28 weight percent), about 29 weight percent, about 30 weight percent, about 31 weight percent, about 32 weight percent, about 33 weight percent, about 34 weight percent), about 35 weight percent, about 36 weight percent, about 37 weight percent, about 38 weight percent, about 39 weight percent, about 40 weight percent, about 41 weight percent, about 42 weight percent, about 43 weight percent, about 44 weight percent, about 45 weight percent, about 46 weight percent, about 47 weight percent, about 48 weight percent, about 49 weight percent, about 50 weight percent, or even higher weight percent silver concentrations.

[0070] In some embodiments, the electrical conductivity of a conductive structure formed from the conductive ink composition is measured. In some embodiments, the electrical conductivity of the conductive structure is measured to be about 2×10 -6 ohm-cm ~ approx. 1 × 10 -5 In some embodiments, the electrical conductivity of the conductive structure is about 3×10 -6 ohm-cm ~ approx. 6 × 10 -6 In some embodiments, the electrical conductivity of the conductive structure is at least about 2×10 ohm-cm. -6 ohm-cm, approximately 3 × 10 -6 ohm-cm, approximately 4 × 10 -6 ohm-cm, approximately 5 × 10 -6 ohm-cm, approximately 6 × 10 -6 ohm-cm, approximately 7 × 10 -6 ohm-cm, approximately 8 × 10 -6 ohm-cm, or approximately 9 × 10 -6 In some embodiments, the electrical conductivity of the conductive structure is at most about 1×10 ohm-cm. -5 ohm-cm, approximately 9 × 10 -6 ohm-cm, approximately 8 × 10 -6 ohm-cm, approximately 7 × 10 -6 ohm-cm, approximately 6 × 10 -6 ohm-cm, approximately 5 × 10 -6 ohm-cm, approximately 4 × 10 -6 ohm-cm, or approximately 3 × 10 -6 It is ohm-cm.

[0071] The electrical conductivity of the conductive structures, in some embodiments, can be expressed in units of ohms per square (also called ohms / square or OPS) in terms of sheet resistivity (i.e., bulk resistivity divided by thickness). For example, in some embodiments, the resistivity of the conductive structures is 5 ohms per square or less, 2 ohms per square or less, 1 ohm per square or less, 0.5 ohms per square or less, or even lower. Preferably, the resistivity of the conductive structures is 1 ohm per square or less.

[0072] The conductive ink compositions of the present disclosure can be used to form conductive structures with high levels of bulk silver. Specifically, in some embodiments, the conductive structures have a bulk silver content of at least 1%. In more specific embodiments, the conductive structures have a bulk silver content of at least 2%, at least 5%, at least 10%, at least 15%, at least 20%, or even higher.

[0073] Method for making conductive ink composition According to another aspect, the present disclosure provides methods for making conductive ink compositions, particularly any of the conductive ink compositions described above. These methods include dissolving silver decanoate in at least one solubilizing agent to form a conductive ink composition, where the silver decanoate comprises at least one α-branched silver decanoate isomer, such as any of the silver decanoates described above, and the at least one solubilizing agent comprises a terpene, a terpenoid, or a combination thereof. The conductive ink compositions formed by these methods preferably further comprise at least one non-acid stabilizer, particularly any of the non-acid stabilizers described above.

[0074] Method for forming a conductive structure In another aspect, a method of making a conductive structure is disclosed. In some embodiments, the method comprises applying any of the conductive ink compositions described above to a suitable substrate. In some embodiments, the method comprises heating the conductive ink composition on the substrate at a decomposition temperature of about 250° C. or less to form the conductive structure. In some embodiments, the method comprises heating the conductive ink composition on the substrate at a decomposition temperature of about 100° C. or less to form the conductive structure. In some embodiments, the method includes heating the conductive ink composition on the substrate to a decomposition temperature of about 210°C or less, about 200°C or less, about 190°C, about 180°C or less, about 170°C or less, about 160°C, about 150°C or less, about 140°C or less, about 130°C or less, about 120°C or less, about 110°C or less, about 90°C or less, about 80°C or less, about 70°C or less, about 60°C or less, or about 50°C or less to form a conductive structure. In some embodiments, the conductive ink composition is heated using a heat source. Examples of heat sources include IR lamps, an oven, or a heated substrate.

[0075] In preferred embodiments, the conductive ink composition of the present method does not include a catalyst. More specifically, in some embodiments, the conductive ink composition of the present method does not include an amine-containing catalyst.

[0076] In some embodiments, the conductive ink composition of the present method has a desired viscosity. In some embodiments, the desired viscosity is obtained using a Micro VISC viscometer. In some embodiments, the conductive ink composition has a viscosity of about 50 centipoise to about 1000 centipoise. In some embodiments, the conductive ink composition has a viscosity of about 5 centipoise to about 50 centipoise. In some embodiments, the conductive ink composition has a viscosity of about 10 centipoise to about 40 centipoise. In some embodiments, the conductive ink composition has a viscosity of about 20 centipoise to about 30 centipoise. In some embodiments, the conductive ink composition has a viscosity of about 18 centipoise to about 20 centipoise. In some embodiments, the conductive ink composition has a viscosity of about 18, about 19, or about 20 centipoise. In some embodiments, the conductive ink composition has a viscosity of at least about 5 centipoise, about 10 centipoise, about 20 centipoise, about 30 centipoise, about 40 centipoise, about 50 centipoise, about 60 centipoise, about 70 centipoise, about 80 centipoise, about 90 centipoise, about 100 centipoise, about 200 centipoise, about 300 centipoise, about 400 centipoise, about 500 centipoise, about 600 centipoise, about 700 centipoise, about 800 centipoise, or about 900 centipoise. In some embodiments, the conductive ink composition has a viscosity of up to about 1000 centipoise, about 900 centipoise, about 800 centipoise, about 700 centipoise, about 600 centipoise, about 500 centipoise, about 400 centipoise, about 300 centipoise, about 200 centipoise, about 100 centipoise, about 90 centipoise, about 80 centipoise, about 70 centipoise, about 60 centipoise, about 50 centipoise, about 40 centipoise, about 30 centipoise, about 20 centipoise, or about 10 centipoise.

[0077] In some embodiments, the viscosity of the conductive ink composition is adjusted based on the amount of solubilizer used. In some embodiments, the viscosity of the complex is adjusted based on the type of solubilizer used. For example, in embodiments where the solubilizer includes limonene and terpineol, increasing the percentage of terpineol in the conductive ink composition can increase the viscosity of the ink. In some embodiments, the viscosity of the silver complex can be adjusted from less than 5 centipoise with a large proportion of limonene to 50 centipoise with a large proportion of terpineol. Unless otherwise indicated, all viscosity values ​​are for samples at room temperature.

[0078] Application of conductive ink composition The conductive ink compositions of the present disclosure can be used in a variety of printing applications, including slot-die coating, spin coating, roll-to-roll printing, including gravure, flexography, rotary screen printing, screen printing, aerosol jet printing, inkjet printing, airbrush, Mayer rod coating, flood coating, 3D printing, dispenser, and electrohydrodynamic printing. In particular, the inks can be used in inkjet printing, dip coating, and spray coating.

[0079] Additionally, photolithography can be used to create patterns, creating masks to etch silver from specific areas, thereby creating high fidelity features. Both positive and negative tone patterning processes may be used to create the patterns.

[0080] In some embodiments, the silver salt of the silver carboxylate is completely dissolved in at least one solubilizer. The completely dissolved silver salt is compatible with many non-polar polymeric, glass, and ceramic substrates, which are particularly difficult to wet with polar complexes. In some embodiments, the conductive ink composition including the silver complex is applied to a polymeric substrate, for example, a flexible polymeric substrate such as a polyimide (PI) substrate, e.g., Kapton. In some embodiments, the conductive ink composition including the silver complex is applied to a non-polar polymeric substrate. In some embodiments, the conductive ink composition including the silver complex is applied to a glass substrate. In some embodiments, the conductive ink composition including the silver complex is applied to a ceramic substrate.

[0081] Furthermore, elastomers and 3D substrates, particularly those having non-planar topography, can be used in conjunction with the conductive structures. In some embodiments, the conductive ink composition comprising the silver complex is applied to an elastomer. In some embodiments, the conductive ink composition comprising the silver complex is applied to a 3D substrate.

[0082] In some embodiments, the conductive ink composition of the present disclosure may be applied to an epoxy substrate, such as an epoxy molding compound (EMC) substrate.

[0083] In some embodiments, the conductive ink composition of the present disclosure may be applied to a silver nanowire (SNW) substrate, a solder resist substrate (also called a solder mask substrate), or any other suitable substrate material.

[0084] In some embodiments, the ink composition of the present method has a metal salt concentration of about 0.1 to 50 percent by weight of the ink composition. In some embodiments, the ink composition of the present method has a metal salt concentration of about 0.1 to 40 percent by weight of the ink composition. In some embodiments, the ink composition has a metal salt concentration of about 1 to 30 percent by weight of the ink composition. In some embodiments, the ink composition has a metal salt concentration of about 1 to 20 percent by weight of the ink composition. In some embodiments, the ink composition has a metal salt concentration of about 1 to 10 percent by weight of the ink composition. In some embodiments, the ink composition has a metal salt concentration of about 5 to 15 percent by weight of the ink composition. In some embodiments, the ink composition has a metal concentration of about 0.1 weight percent, about 0.2 weight percent, about 0.3 weight percent, about 0.4 weight percent, about 0.5 weight percent, about 0.6 weight percent, about 0.7 weight percent, about 0.8 weight percent, about 0.9 weight percent, about 1 weight percent, about 2 weight percent, about 3 weight percent, about 4 weight percent), about 5 weight percent, about 6 weight percent, about 7 weight percent, about 8 weight percent, about 9 weight percent, about 10 weight percent, about 11 weight percent, about 12 weight percent, about 13 weight percent, about 14 weight percent, about 15 weight percent, about 16 weight percent, about 17 weight percent, about 18 weight percent, about 19 weight percent, or about 20 weight percent of the ink composition.

[0085] In some embodiments, the ink composition of the present method has a metal salt concentration of at least about 0.1 weight percent, about 0.2 weight percent, about 0.3 weight percent, about 0.4 weight percent, about 0.5 weight percent, about 0.6 weight percent, about 0.7 weight percent, about 0.8 weight percent, about 0.9 weight percent, 1 weight percent, about 2 weight percent, about 3 weight percent, about 4 weight percent), about 5 weight percent), about 6 weight percent, about 7 weight percent, about 8 weight percent, about 9 weight percent, about 10 weight percent, about 11 weight percent), about 12 weight percent, about 13 weight percent, about 14 weight percent, about 15 weight percent, about 16 weight percent, about 17 weight percent), about 18 weight percent, about 19 weight percent, or about 20 weight percent of the ink composition. In some embodiments, the ink composition has a metal salt concentration of up to about 40 weight percent, about 39 weight percent, about 38 weight percent, about 37 weight percent, about 36 weight percent, about 35 weight percent, about 34 weight percent, about 33 weight percent, about 32 weight percent, 31 weight percent, about 30 weight percent, about 29 weight percent, about 28 weight percent, about 27 weight percent, about 26 weight percent, about 25 weight percent, about 24 weight percent, about 23 weight percent, about 22 weight percent, about 21 weight percent, about 20 weight percent, about 19 weight percent, about 18 weight percent, about 17 weight percent, about 16 weight percent, about 15 weight percent, about 14 weight percent, about 13 weight percent, or about 12 weight percent of the ink composition.

[0086] In some embodiments, the ink composition of the present method has a metal complex concentration of about 0.1 to 50 percent by weight of the ink composition. In some embodiments, the ink composition of the present method has a metal complex concentration of about 0.1 to 40 percent by weight of the ink composition. In some embodiments, the ink composition has a metal complex concentration of about 1 to 30 percent by weight of the ink composition. In some embodiments, the ink composition has a metal complex concentration of about 1 to 20 percent by weight of the ink composition. In some embodiments, the ink composition has a metal complex concentration of about 1 to 10 percent by weight of the ink composition. In some embodiments, the ink composition has a metal complex concentration of about 5 to 15 percent by weight of the ink composition. In some embodiments, the ink composition has a metal complex concentration of about 0.1 weight percent, about 0.2 weight percent, about 0.3 weight percent, about 0.4 weight percent, about 0.5 weight percent, about 0.6 weight percent, about 0.7 weight percent, about 0.8 weight percent, about 0.9 weight percent), 1 weight percent), about 2 weight percent, about 3 weight percent, about 4 weight percent, about 5 weight percent, about 6 weight percent, about 7 weight percent), about 8 weight percent), about 9 weight percent, about 10 weight percent, about 11 weight percent, about 12 weight percent, about 13 weight percent), about 14 weight percent), about 15 weight percent, about 16 weight percent, about 17 weight percent, about 18 weight percent, about 19 weight percent, or about 20 weight percent of the ink composition.

[0087] Decomposition In another aspect, the conductive ink composition of the present disclosure is decomposed on a substrate to form a conductive structure on the substrate. In some embodiments, the conductive ink composition is decomposed by heating the reducible metal complex at a temperature of about 270°C or less. In some embodiments, the conductive ink composition is decomposed by heating the conductive ink composition at a temperature of about 260°C or less, about 250°C or less, about 240°C or less, about 230°C or less, about 220°C or less, about 210°C or less, about 200°C or less, about 190°C or less, about 180°C or less, about 170°C or less, about 160°C or less, about 150°C or less, about 140°C or less, about 130°C or less, about 120°C or less, about 110°C or less, about 100°C or less, about 90°C or less, about 80°C or less, or about 70°C or less. In some embodiments, the conductive ink composition is heated by a heat source, examples of which include an IR lamp, an oven, or a heated substrate.

[0088] In some embodiments, the conductive ink composition is decomposed by exposing the composition to a light source having a wavelength of about 100 nm to about 1500 nm. In some embodiments, the conductive ink composition is decomposed by exposing the composition to a light source such as a xenon lamp or an IR lamp having a wavelength of about 100 nm to about 1000 nm. In some embodiments, the conductive ink composition is decomposed by exposing the composition to a light source having a wavelength of about 100 nm to about 700 nm. In some embodiments, the conductive ink composition is decomposed by exposing the composition to a light source having a wavelength of about 100 nm to about 500 nm. In some embodiments, the conductive ink composition is decomposed by exposing the composition to a light source having a wavelength of about 100 nm to about 300 nm. In some embodiments, the conductive ink composition is decomposed by exposing the composition to a light source having a wavelength of about 100 nm, about 200 nm, about 300 nm, about 400 nm, about 500 nm, about 600 nm, about 700 nm, about 800 nm, about 900 nm, or about 1000 nm.

[0089] In some embodiments, the conductive ink composition is decomposed by a combination of heating the reducible metal complex, e.g., at any of the temperatures listed above, and exposing the composition to a light source, e.g., at any of the wavelengths listed above.

[0090] In some embodiments, the electrical conductivity of the conductive structure is measured. In some embodiments, the electrical conductivity of the conductive structure is measured to be about 1×10 -6 In some embodiments, the electrical conductivity of the conductive structure is about 1×10 ohm-cm or higher. -6 ohm-cm ~ approx. 8 × 10 -4 In some embodiments, the electrical conductivity of the conductive structure is about 3×10 -6 ohm-cm ~ approx. 6 × 10 -6 In some embodiments, the electrical conductivity of the conductive structure is at least about 1×10 ohm-cm. -6 ohm-cm, approximately 2 × 10 -6 ohm-cm, approximately 3 × 10 -6 ohm-cm, approximately 4 × 10 -6 ohm-cm, approximately 5 × 10 -6 ohm-cm, approximately 6 × 10 -6 ohm-cm, approximately 7 × 10 -6 ohm-cm, approximately 8 × 10 -6 ohm-cm, approximately 9 × 10 -6 ohm-cm, approximately 1 x 10 -5 ohm-cm, approximately 2 × 10 -5 ohm-cm, approximately 3 × 10 -5 ohm-cm, approximately 4 × 10 -5 ohm-cm, approximately 5 × 10 -5 ohm-cm, approximately 6 × 10 -5 ohm-cm, approximately 7 × 10 -5 ohm-cm, approximately 8 × 10 -5 ohm-cm, approximately 9 × 10 -5 ohm-cm, approximately 1 x 10 -4 ohm-cm, approximately 2 × 10 -4 ohm-cm, approximately 3 × 10 -4 ohm-cm, approximately 4 × 10 -4ohm-cm, approximately 5 × 10 -4 ohm-cm, approximately 6 × 10 -4 ohm-cm, or approximately 7 × 10 -4 In some embodiments, the electrical conductivity of the conductive structure is at most about 8×10 ohm-cm. -4 ohm-cm, 7 × 10 -4 ohm-cm, approximately 6 × 10 -4 ohm-cm, approximately 5 × 10 -4 ohm-cm, approximately 4 × 10 -4 ohm-cm, approximately 3 × 10 -4 ohm-cm, approximately 2 × 10 -4 ohm-cm, or approximately 1×10 -4 ohm-cm, approximately 9 × 10 -5 ohm-cm, approximately 8 × 10 -5 ohm-cm, approximately 7 × 10 -5 ohm-cm, approximately 6 × 10 -5 ohm-cm, approximately 5 × 10 -5 ohm-cm, approximately 4 × 10 -5 ohm-cm, approximately 3 × 10 -5 ohm-cm, approximately 2 × 10 -5 ohm-cm, approximately 1 x 10 -5 ohm-cm, approximately 9 × 10 -6 ohm-cm, approximately 8 × 10 -6 ohm-cm, approximately 7 × 10 -6 ohm-cm, approximately 6 × 10 -6 ohm-cm, approximately 5 × 10 -6 ohm-cm, approximately 4 × 10 -6 ohm-cm, approximately 3 × 10 -6 ohm-cm, or approximately 2 × 10 -6 It is ohm-cm.

[0091] It will be readily apparent to those skilled in the relevant art that other suitable modifications and adaptations to the compositions and methods described herein can be made without departing from the scope of the invention or any embodiment thereof. Having now described the invention in detail, the present invention will be more clearly understood by reference to the following examples. The following examples are included herein for illustrative purposes only and are not intended to limit the invention. [Example]

[0092] Preparation of silver decanoate The decanoic acid used to form the silver carboxylate of the improved conductive ink composition preferably comprises at least one α-branched decanoic acid isomer. Decanoic acid can be converted to silver decanoate for use in the conductive ink composition according to the following general protocol: [ka] In the above structure, R1 and R2 are each independently an alkyl group, R3 is either a hydrogen or an alkyl group, and R1, R2, and R3 collectively contain a total of 8 carbon atoms.

[0093] In one exemplary preparation of silver decanoate isomer mixture, AgO powder (13.58 g, 0.058 mol) was slowly added to a solution of decanoic acid isomer mixture (21.20 g, 0.12 mol) in dry THF (175 mL) and stirred at room temperature. After 3 hours, the black silver oxide dissolved to form an off-white solution. The mixture was stirred overnight until it became a creamy white solution. Upon completion, methanol (600 mL) was poured into the mixture to precipitate silver decanoate. The solvent was removed, and additional methanol (600 mL) was added to remove excess decanoic acid. Finally, the excess methanol was removed, and silver decanoate was collected by centrifugation as a white solid (20 g, 60%). [ka]

[0094] In another exemplary preparation of silver decanoate, AgO powder (3.01 g, 0.013 mol) was slowly added to a solution of 2,2-diethylhexanoic acid (5.000 g, 0.029 mol) in dry THF (45 mL) and stirred at room temperature. After 24 h, the black silver oxide dissolved to form an off-white solution. The mixture was stirred for another 24 h until it became a creamy white solution. Upon completion, methanol (200 mL) was poured into the mixture to precipitate silver 2,2-diethylhexanoate (Ag-2,2-DEHA). The solvent was removed, and additional methanol (200 mL) was added to remove excess 2,2-diethylhexanoic acid. Finally, the excess methanol was removed, and Ag-2,2-DEHA was collected by centrifugation as a white solid (1.74 g, 21%). [ka]

[0095] In yet another exemplary preparation of silver decanoate, AgO powder (3.01 g, 0.013 mol) was slowly added to a solution of 2-butylhexanoic acid (5.000 g, 0.029 mol) in dry THF (45 mL) and stirred at room temperature. After 48 hours, the black silver oxide dissolved to form an off-white solution. The mixture was stirred for an additional 24 hours until it became a creamy white solution. Upon completion, methanol (200 mL) was poured into the mixture to precipitate silver 2-butylhexanoate (Ag-2-BHA). The solvent was removed, and additional methanol (200 mL) was added to remove excess 2-butylhexanoic acid. Finally, the excess methanol was removed, and Ag-2-BHA was collected by centrifugation as a white solid (3.4 g, 42%).

[0096] Exemplary ink formulations containing silver decanoate and their cure profiles Conductive ink compositions are generally prepared as described in U.S. Patent Application No. 63 / 316,949, filed March 4, 2022, U.S. Patent Application No. 63 / 370,343, filed August 3, 2022, and U.S. Patent Application No. 63 / 384,202, filed November 17, 2022.

[0097] Formulation 1 The control ink formulation contained 45% silver decanoate isomer mixture in 55% limonene with 3% decanoic acid isomer mixture post-added as an acid stabilizer. In the following formulations, the post-added decanoic acid isomer stabilizer is replaced with the test stabilizer compound indicated.

[0098] Formulation 2 45% silver decanoate isomer mixture in 55% limonene with post-addition of 3% 3,5-heptanedione.

[0099] Formulation 3 45% silver decanoate isomer mixture in 55% limonene with post-addition of 3% 3-methyl-2,4-pentanedione.

[0100] Formulation 4 45% silver decanoate isomer mixture in 55% limonene with post-addition of 3% 3-ethyl-2,4-pentanedione.

[0101] Formulation 5 45% silver decanoate isomer mixture in 55% limonene with post-addition of 3% 1-phenyl-1,3-butanedione.

[0102] Formulation 6 45% silver decanoate isomer mixture in 55% limonene with post-addition of 3% 3,3-dimethyl-2,4-pentanedione.

[0103] Formulation 7 45% silver decanoate isomer mixture in 55% limonene with post-addition of 3% 2,2,6,6-tetramethyl-3,5-heptanedione.

[0104] Formulation 8 45% silver decanoate isomer mixture in 55% limonene with post-addition of 3% 3-benzylidene-2,4-pentanedione.

[0105] Formulation 9 45% silver decanoate isomer mixture in 55% limonene with post-addition of 3% 3-benzyl-2,4-pentanedione.

[0106] Formulation 10 45% silver decanoate isomer mixture in 55% limonene with post-addition of 0.5% (3-glycidyloxypropyl)trimethoxysilane (GLYMO) and 3% 3,3-dimethyl-2,4-pentanedione.

[0107] Formulation 11 45% silver decanoate isomer mixture in 55% limonene with post-addition of 0.5% (3-glycidyloxypropyl)trimethoxysilane (GLYMO) and 3% 2,2,6,6-tetramethyl-3,5-heptanedione.

[0108] Formulation 12 45% silver decanoate isomer mixture in 55% limonene with 0.5% decanoic acid isomer mixture post-added.

[0109] Formulation 13 45% silver decanoate isomer mixture in 55% limonene with post-addition of 1% 3,3-dimethyl-2,4-pentanedione.

[0110] Formulation 14 45% silver decanoate isomer mixture in 55% limonene with post-addition of 1% 2,2,6,6-tetramethyl-3,5-heptanedione.

[0111] Formulation 15 45% silver decanoate isomer mixture in 55% limonene with post-addition of 0.5% decanoic acid isomer mixture and 0.5% 3,3-dimethyl-2,4-pentanedione.

[0112] Formulation 16 45% silver decanoate isomer mixture in 55% limonene with post-addition of 0.5% decanoic acid isomer mixture and 0.5% 2,2,6,6-tetramethyl-3,5-heptanedione.

[0113] Characterization of conductive ink formulations containing β-diketone stabilizers Figure 1 shows the low temperature stability of Formulations 1-7. Each formulation was sealed in a glass vial and held at 4°C for the indicated time. As indicated in the above descriptions of these formulations, each sample contained 45% silver decanoate isomer mixture, 55% limonene, and 3% test stabilizer. The control, Formulation 1, contained 3% post-added decanoic acid isomer mixture in place of the test stabilizer.

[0114] Test solutions that remain clear throughout the test period (ie, Formulations 6 and 7 on day 13) are considered stable under the test conditions.

[0115] Figure 2 shows the stability of Formulations 1-7 at elevated temperatures. Each formulation was sealed in a glass vial and held at 40°C for the indicated time. Only the control solution (Formulation 1) remained clear throughout the test period and was considered stable under the test conditions.

[0116] Figure 3 shows the high temperature stability of Formulations 1, 4, 6, 7, 8, and 9. As shown in this experiment, Formulations 1, 6, and 7 (only those vials shown at 23 and 28 days) remained clear for at least 28 days at 30°C under the test conditions.

[0117] Table 1 summarizes the resistivity of conductive structures formed from stable inks formulated with and without adhesion promoters. All inks were bar coated onto microscope glass using an appropriate bar and cured at 180°C for 1 hour. [Table 1]

[0118] The results shown in Table 1 indicate that the added components are easily removed from the conductive structures upon curing and do not affect resistivity. Furthermore, all inks tested in Table 1 print well under standard conditions.

[0119] Figure 4 shows the effect of stabilizer concentration on the stability of the ink formulation at 30° C. These results show that the stabilizer concentration can be reduced without significantly reducing the stability of the ink at this temperature and for these times.

[0120] All patents, patent publications, and other published references referred to herein are incorporated by reference in their entirety, as if each was individually and specifically incorporated by reference herein.

[0121] While specific examples have been provided, the above description is illustrative and not limiting. Any one or more of the features of the above-described embodiments may be combined in any manner with one or more features of any other embodiment of the present invention. Moreover, many variations of the present invention will become apparent to those skilled in the art upon review of this specification. Therefore, the scope of the present invention should be determined by reference to the appended claims, along with their full scope of equivalents.

Claims

1. Silver decanoate, at least one lysis agent, and at least one non-acid stabilizer A conductive ink composition comprising: the at least one lysing agent comprises a terpene, a terpenoid, or a combination thereof; A conductive ink composition, wherein the silver decanoate is decarboxylated at a temperature of 250° C. or less to form conductive structures.

2. The conductive ink composition of claim 1, wherein the at least one non-acid stabilizer is a β-diketone.

3. The β-diketone has the structure of formula (I): 【Chemistry 12】 [In the formula, each R ４ The groups are independently a C optionally substituted aryl group. １ ~C ６ is a straight or branched chain alkyl group or an aryl group; Each R ５ The groups are independently —H, C optionally substituted with aryl groups. １ ~C ６ a straight or branched chain alkyl group, or two R ５ The groups taken together form a C １ ~C ６ 3. The conductive ink composition of claim 2, wherein the double bond optionally substituted with a straight or branched chain alkyl group or the double bond optionally substituted with an aryl group.

4. Each R ４ and R ５ The conductive ink composition of claim 3 , wherein the groups are independently substituted with an alkoxy, hydroxy, thio, amino, halo, cyano, or nitro group.

5. Each R ４ groups are independently optionally substituted with phenyl groups １ ~C ４ a straight or branched chain alkyl group or a phenyl group; Each R ５ groups are independently —H, C optionally substituted with phenyl groups １ ~C ４ a straight or branched chain alkyl group, or two R ５ The groups taken together form a C optionally further substituted phenyl group. １ ~C ４ 4. The conductive ink composition of claim 3, wherein the double bond is optionally substituted with a straight or branched chain alkyl group or a phenyl group.

6. Each R ４ groups are independently methyl, ethyl, or phenyl; Each R ５ groups are independently hydrogen, methyl, ethyl, or benzyl, or two R ５ The conductive ink composition of claim 5 , wherein the groups together form a double bond that is optionally substituted with a methyl, ethyl, or phenyl group.

7. 2. The conductive ink composition of claim 1, wherein the silver decanoate comprises at least one α-branched silver decanoate isomer.

8. 2. The conductive ink composition of claim 1, wherein the silver decanoate comprises a plurality of α-branched silver decanoate isomers.

9. The silver decanoate has the structure: 【Chemistry 13】 [In the formula, R １ and R ２ are each independently an alkyl group, and R ３ is either hydrogen or an alkyl group, and R １ , R ２ and R ３ 10. The conductive ink composition of claim 1, wherein collectively, each of the groups contains a total of 8 carbon atoms.

10. R １ and R ２ The conductive ink composition of claim 9 , wherein each is independently methyl or ethyl.

11. 10. The conductive ink composition of claim 9, wherein the silver decanoate comprises silver 2,2-dimethyloctanoate, silver 2,2,3,5-tetramethylhexanoate, silver 2,4-dimethyl-2-isopropylpentanoate, silver 2,5-dimethyl-2-ethylhexanoate, silver 2,2-diethylhexanoate, silver 2-butylhexanoate, or a combination thereof.

12. The conductive ink composition of claim 1 , wherein the conductive ink composition is particle-free.

13. The conductive ink composition of claim 1 , wherein the terpene is a purified terpene or the terpenoid is a purified terpenoid.

14. The conductive ink composition of claim 1 , wherein the terpene is pinene or limonene.

15. The conductive ink composition of claim 1 , wherein the terpenoid is terpineol.

16. The conductive ink composition of claim 1 , wherein the at least one solubilizing agent comprises limonene.

17. The conductive ink composition of claim 16 , wherein the limonene is purified limonene.

18. The conductive ink composition of claim 1 further comprising an adhesion promoter.

19. The conductive ink composition of claim 18 , wherein the adhesion promoter comprises a reactive silane.

20. The conductive ink composition of claim 19 , wherein the adhesion promoter comprises an alkoxysilane.

21. The conductive ink composition of claim 20 , wherein the adhesion promoter comprises an ethoxysilyl-modified polyalkene.

22. 22. The conductive ink composition of claim 21, wherein the adhesion promoter comprises triethoxysilyl-modified poly-1,2-butadiene.

23. The conductive ink composition of claim 18 , wherein the adhesion promoter comprises a reactive silane and an epoxide.

24. The adhesion promoter has the structure of formula (II): 【Chemistry 14】 wherein each R′ is independently C １ ~C ６ and L' is an alkyl linker group.

25. 25. The conductive ink composition of claim 24, wherein each R' is independently a methyl or ethyl group.

26. L' is C ２ ~C １０ The conductive ink composition of claim 24, wherein the linker group is an alkyl group.

27. L' is a substituted C ２ ~C １０ The conductive ink composition of claim 26, wherein the linker group is an alkyl group.

28. 28. The conductive ink composition of claim 27, wherein one or more carbon atoms of L' are replaced with a heteroatom.

29. The adhesion promoter has a structure of formula (III): 【Chemistry 15】 25. The conductive ink composition of claim 24, having the formula: wherein each R' is independently a methyl or ethyl group, X is a heteroatom, and each n is independently 1 to 6.

30. 30. The conductive ink composition of claim 29, wherein each R' is a methyl group, X is oxygen, and each n is independently 1 to 3.

31. The adhesion promoter is 【Chemistry 16】 25. The conductive ink composition of claim 24, wherein

32. The conductive ink composition of claim 23 , wherein the adhesion promoter comprises an alkoxysilane.

33. 33. The conductive ink composition of claim 32, wherein the adhesion promoter comprises a methoxysilyl or ethoxysilyl group.

34. The conductive ink composition of claim 1 further comprising an acid stabilizer.

35. The acid stabilizer is C ６～１２ The conductive ink composition of claim 34, which is an α-branched alkanoic acid.

36. 36. The conductive ink composition of claim 35, wherein the acid stabilizer is an α-branched decanoic acid isomer.

37. The conductive ink composition of claim 36, wherein the acid stabilizer is 2,2-dimethylhexanoic acid or 2,2-dimethylnonanoic acid.

38. 10. The conductive ink composition of claim 1, wherein the silver decanoate comprises at least one α-branched silver decanoate isomer, the at least one solubilizer is limonene, the at least one non-acid stabilizer is a β-diketone, and the conductive ink composition further comprises an adhesion promoter comprising a reactive silane.

39. 39. The conductive ink composition of claim 38, further comprising an acid stabilizer.

40. 10. The conductive ink composition of claim 1, wherein the silver decanoate comprises at least one α-branched silver decanoate isomer, the at least one solubilizer is limonene, the at least one non-acid stabilizer is a β-diketone, and the conductive ink composition further comprises an acid stabilizer.

41. 10. The conductive ink composition of claim 1, wherein the conductive ink composition has a concentration of silver decanoate of about 1 to about 50 weight percent.

42. The conductive ink composition of claim 1, wherein the conductive ink composition has a viscosity of about 5 centipoise to about 50 centipoise.

43. The conductive ink composition of claim 1, wherein the conductive ink composition has a viscosity of about 50 centipoise to about 1000 centipoise.

44. 10. The conductive ink composition of claim 1, wherein the conductive structures have a resistivity of 5 ohms per square or less, 2 ohms per square or less, 1 ohm per square or less, or 0.5 ohms per square or less.

45. The conductive ink composition of claim 1 , wherein the conductive structures have a bulk silver content of at least 1%.

46. The conductive ink composition of claim 1 , wherein the silver decanoate is decarboxylated at a temperature of 180° C. or less to form conductive structures.

47. The conductive ink composition of claim 1 , wherein the silver decanoate is decarboxylated at a temperature of 150° C. or less to form conductive structures.

48. 1. A method of making a conductive ink composition, comprising: dissolving silver decanoate in at least one solubilizer to form a conductive ink composition. Including, the silver decanoate comprises at least one α-branched silver decanoate isomer, and the at least one solubilizing agent comprises a terpene, a terpenoid, or a combination thereof; the conductive ink composition further comprises at least one non-acid stabilizer; method.

49. 49. The method of claim 48, wherein the at least one non-acid stabilizer is a β-diketone.

50. The β-diketone has the structure of formula (I): 【Chemistry 17】 [In the formula, each R ４ The groups are independently a C optionally substituted aryl group. １ ~C ６ is a straight or branched chain alkyl group or an aryl group; Each R ５ The groups are independently —H, C optionally substituted with aryl groups. １ ~C ６ a straight or branched chain alkyl group, or two R ５ The groups taken together form a C １ ~C ６ 50. The method of claim 49, wherein the double bond optionally substituted with a straight or branched chain alkyl group, or the double bond optionally substituted with an aryl group.

51. Each R ４ and R ５ 51. The method of claim 50, wherein the groups are independently substituted with alkoxy, hydroxy, thio, amino, halo, cyano, or nitro groups.

52. Each R ４ groups are independently optionally substituted with phenyl groups １ ~C ４ a straight or branched chain alkyl group or a phenyl group; Each R ５ groups are independently —H, C optionally substituted with phenyl groups １ ~C ４ a straight or branched chain alkyl group, or two R ５ The groups taken together form a C optionally further substituted phenyl group. １ ~C ４ 51. The method of claim 50, wherein the double bond is formed as an optionally substituted straight or branched chain alkyl group or as an optionally substituted phenyl group.

53. Each R ４ groups are independently methyl, ethyl, or phenyl; Each R ５ groups are independently hydrogen, methyl, ethyl, or benzyl, or two R ５ 53. The method of claim 52, wherein the groups taken together form a double bond optionally substituted with a methyl, ethyl, or phenyl group.

54. 49. The method of claim 48, wherein the conductive ink composition is particle-free.

55. 49. The method of claim 48, wherein the silver decanoate comprises a plurality of α-branched silver decanoate isomers.

56. The silver decanoate has the structure: [Chemistry 18] [In the formula, R １ and R ２ are each independently an alkyl group, and R ３ is either hydrogen or an alkyl group, and R １ , R ２ and R ３ 49. The method of claim 48, wherein collectively, the alkyl groups have a total of 8 carbon atoms.

57. R １ and R ２ 57. The method of claim 56, wherein each is independently methyl or ethyl.

58. 57. The method of claim 56, wherein the silver decanoate comprises silver 2,2-dimethyloctanoate, silver 2,2,3,5-tetramethylhexanoate, silver 2,4-dimethyl-2-isopropylpentanoate, silver 2,5-dimethyl-2-ethylhexanoate, silver 2,2-diethylhexanoate, silver 2-butylhexanoate, or a combination thereof.

59. 49. The method of claim 48, wherein the terpene is a purified terpene or the terpenoid is a purified terpenoid.

60. 49. The method of claim 48, wherein the terpene is pinene or limonene.

61. 49. The method of claim 48, wherein the terpenoid is terpineol.

62. 49. The method of claim 48, wherein the at least one lysing agent comprises limonene.

63. 63. The method of claim 62, wherein the limonene is purified limonene.

64. 49. The method of claim 48, wherein the conductive ink composition further comprises at least one adhesion promoter.

65. 65. The method of claim 64, wherein the at least one adhesion promoter comprises a reactive silane.

66. 66. The method of claim 65, wherein the at least one adhesion promoter comprises an alkoxysilane.

67. 67. The method of claim 66, wherein the at least one adhesion promoter comprises an ethoxysilyl-modified polyalkene.

68. 68. The method of claim 67, wherein the at least one adhesion promoter comprises triethoxysilyl-modified poly-1,2-butadiene.

69. 65. The method of claim 64, wherein the at least one adhesion promoter comprises a reactive silane and an epoxide.

70. The at least one adhesion promoter has the structure of formula (II): 【Chemistry 19】 wherein each R′ is independently C １ ~C ６ and L' is an alkyl linker group.

71. 71. The method of claim 70, wherein each R' is independently a methyl or ethyl group.

72. L' is C ２ ~C １０ - an alkyl linker group.

73. L' is a substituted C ２ ~C １０ - an alkyl linker group.

74. 74. The method of claim 73, wherein one or more carbon atoms of L' are replaced with a heteroatom.

75. The at least one adhesion promoter has a structure of formula (III): 【Chemistry 20】 71. The method of claim 70, having the formula: wherein each R' is independently a methyl or ethyl group, X is a heteroatom, and each n is independently 1 to 6.

76. 76. The method of claim 75, wherein each R' is a methyl group, X is oxygen, and each n is independently 1 to 3.

77. said at least one adhesion promoter 【Chemistry 21】 71. The method of claim 70, wherein:

78. 70. The method of claim 69, wherein the at least one adhesion promoter comprises an alkoxysilane.

79. 79. The method of claim 78, wherein the at least one adhesion promoter comprises a methoxysilyl or ethoxysilyl group.

80. 49. The method of claim 48, wherein the conductive ink composition further comprises at least one acid stabilizer.

81. The at least one acid stabilizer is C ６～１２ 81. The method of claim 80, wherein the alkanoic acid is an α-branched alkanoic acid.

82. 82. The method of claim 81, wherein the at least one acid stabilizer is an α-branched decanoic acid isomer.

83. 83. The method of claim 82, wherein the at least one acid stabilizer is 2,2-dimethylhexanoic acid or 2,2-dimethylnonanoic acid.

84. 49. The method of claim 48, wherein the silver decanoate comprises at least one α-branched silver decanoate isomer, the at least one solubilizer comprises limonene, and the conductive ink composition further comprises at least one adhesion promoter comprising a reactive silane.

85. 85. The method of claim 84, wherein the conductive ink composition further comprises at least one acid stabilizer.

86. 49. The method of claim 48, wherein the silver decanoate comprises at least one α-branched silver decanoate isomer, the at least one solubilizing agent comprises limonene, and the conductive ink composition further comprises at least one acid stabilizer.

87. 49. The method of claim 48, wherein the conductive ink composition has a concentration of silver decanoate of from about 1 to about 50 weight percent.

88. 49. The method of claim 48, wherein the conductive ink composition has a viscosity of about 5 centipoise to about 50 centipoise.

89. 49. The method of claim 48, wherein the conductive ink composition has a viscosity of about 50 centipoise to about 1000 centipoise.

90. 49. The method of claim 48, wherein the silver decanoate is decarboxylated at a temperature of 180° C. or less to form a conductive structure.

91. 49. The method of claim 48, wherein the silver decanoate is decarboxylated at a temperature of 150° C. or less to form a conductive structure.

92. 1. A method of forming a conductive structure, comprising: applying the conductive ink composition of any one of claims 1 to 47 to a substrate; heating the conductive ink composition on the substrate to a temperature of about 250° C. or less to form the conductive structure; A method comprising:

93. 93. The method of claim 92, wherein the conductive ink composition is applied by gravure, flexography, rotary screen printing, screen printing, aerosol jet printing, ink jet printing, airbrush, Mayer rod coating, flood coating, 3D printing, slot die coating, spin coating, roll-to-roll printing including dispenser or electrohydrodynamic printing.

94. 93. The method of claim 92, wherein the conductive structure has a resistivity of 5 ohms per square or less, 2 ohms per square or less, 1 ohm per square or less, or 0.5 ohms per square or less.

95. 93. The method of claim 92, wherein the conductive structure has a bulk silver content of at least 1%.

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