Dual-Mode Silver Itaconate Conductive Ink: Bridging Ultra-Precise Electronics and Flexible Sensors via Tunable...

The demand for ultraprecision and multifunctional electronic devices has driven advancements in printed electronics, particularly in conductive inks that enable high-resolution patterning and compatibility with flexible substrates at low processing temperatures. While silver nanoparticle (AgNP)-based inks have been widely adopted, nonparticulate alternatives like silver itaconate (AgIt) remain underexplored. AgIt, a compound derived from itaconic acid, presents a promising precursor due to its molecular structure, which enhances thermal stability and enables precise control over decomposition behavior, morphology, and particle size of the resulting silver. Despite these advantages, AgIt-based inks have not been systematically investigated for electronic applications. Here, we developed a dual-mode, particle-free conductive ink using AgIt as a precursor. Initially, the AgIt-diamine (AgIt-DAP) ink required high-temperature sintering to achieve optimal conductivity, although it shows excellent stability. By introducing formic acid, we created a silver-amine-acid complex ink (AgIt-DAP-FA) that achieved a dramatic improvement in electrical performance at low temperatures, significantly expanding its versatility. Our work highlights three key innovations: (1) the acid-induced tunability of the AgIt-DAP ink, which enhanced conductivity by 10⁷ times under mild conditions; (2) the comprehensive elucidation of the decomposition mechanisms and performance modulation before and after acid modification, providing critical insights into the silver film formation process; and (3) the demonstration of the ink's adaptability to both rigid and flexible substrates through Ultra-Precise Deposition (UPD) and inkjet printing techniques. The AgIt-DAP ink was successfully employed to fabricate ultraprecise LED circuits on glass substrates, while the AgIt-DAP-FA ink enabled the development of high-sensitivity flexible sensors on polymers. This work bridges material innovation with practical application, offering a universal strategy for designing tunable, particle-free conductive inks. By addressing limitations in substrate compatibility and performance adaptability, our AgIt-based ink system advances the development of next-generation printed electronics for LEDs, wearable sensors, and multifunctional devices.