Sonia Ceron

In this work, silver nanoparticles (AgNPs) used in conductive inks were synthesized for implementation in printable and flexible electronics. The nanoparticles were obtained using silver nitrate as a precursor agent, sodium citrate as a reductive/protective agent and sodium borohydride as a reductive, whose concentrations were varied for optimization. The optical absorption, morphology, size-distribution, crystallinity and stability over time of the processed nanoparticles were determined upon the content of the chemical contents. The AgNPs-based inks were then tested as conductive wires drawn on different common flexible substrates to measure their electrical characteristics and demonstrate their relevance in printable electronics.

In this work, an eco-friendly 3D screen printing technique implemented in roll-to-roll technology for the manufacturing of flexible electronics is presented. The conductive ink was prepared through the decomposition of hydrogen peroxide, an eco-friendly reagent, onto the surfaces of silver nanoparticles. A biodegradable master pattern for screen printing was printed by 3D fused deposition modeling using a polylactic acid filament. This technique was implemented to fabricate hybrid touch-sensitive sensors, to be used as electrical switches, on both photographic and conventional office papers. The functionality of these sensors was demonstrated, and the systems were tested under aging and bending conditions, proving the reliability of this technological approach in flexible electronics and offering a biodegradable alternative.

The functionalization of conductive inks has been carried out through the decomposition of hydrogen peroxide (H₂O₂) onto the surface of silver nanoparticles (AgNPs). The ink prepared using this eco-friendly chemical reagent has been characterized structurally, chemically, and morphologically, showing the presence of stable AgNPs with suitable properties as well as the absence of residual contamination. The electrical conductivity of such a solution-processable ink is evidenced for patterns designed on flexible photographic paper substrates, using a refillable fountain pen that is implemented as a printing mechanism for the fabrication of simple printed circuit boards (PCBs). The functionality and durability of the tested systems are demonstrated under various mechanical constraints, aiming to basically reproduce the normal operation conditions of flexible electronic devices. The obtained results indicate that the implementation of these AgNP-based inks is relevant for direct applications in inkjet printing technology, thus paving the way for the use of greener chemicals in ink preparation.