AgNP Ink Research Articles

Room-temperature Sinterable Silver Nanoparticle Ink with Low-molecular-weight Poly(N-vinylpyrrolidone) Ligand

Abstract A highly conductive silver (Ag) film or pattern was prepared on a poly(ethylene terephthalate) (PET) substrate by using room-temperature sinterable silver nanoparticle (AgNP) ink without any thermal treatment. The most critical factor in the room-temperature sintering of the AgNP ink was the molecular weight of the poly(N-vinylpyrrolidone) (PVP) ligand. AgNP-10 ink having a PVP ligand with the lowest molecular weight of 10000 Da produced a conductive Ag film with 6.3% of the conductivity of bulk silver without any post-treatment such as heating.

Fabrication of an organic field effect transistor using nano imprinting of Ag inks and semiconducting polymers

A simple and cheap procedure for flexible electronics fabrication was demonstrated by imprinting metallic nanoparticles (NPs) on flexible substrates. Silver NPs with an average diameter of 10 nm were prepared via an improved chemical approach and Ag Np ink was produced in α-terpineol with a concentration up to 15%. Silver micro/nanostructures with a dimension varying from nanometres to microns were produced on a flexible substrate (polyimide) by imprinting the as-prepared silver ink. The fine fluidic properties of an Ag NP/α-terpineol solution and low melting temperatures of silver nanoparticles render a low pressure and low temperature procedure, which is well suited for flexible electronics fabrication. The effects of sintering and mechanical bending on the conductivity of imprinted silver contacts were also investigated. Large area organic field effect transistors (OFET) on flexible substrates were fabricated using an imprinted silver electrode and semiconducting polymer. The OFET with silver electrodes imprinted from our prepared oleic acid stabilized Ag nanoparticle ink show an ideal ohmic contact; therefore, the OFET exhibit high performance (Ion/Ioff ratio: 1 × 103; mobility: 0.071 cm2 V−1 s−1).

Dip Pen Nanolithography of Conductive Silver Traces

We report the first demonstration of subμm, sub-50-μΩ·cm conductive traces directly written by Dip Pen Nanolithography (DPN). We achieved subμm Ag lines with 28.8 μΩ·cm average resistivity after direct-write printing from a silver nanoparticle-based ink suspension and annealing at 150 °C for 10 min. This compares to Ag bulk resistivity of 1.63 μΩ·cm, where the difference is within the range of previously reported variations in conductivity of Ag-based inks due to annealing conditions and larger width scales. We leveraged DPN’s ability to directly place materials at specific locations in order to fabricate and characterize these conductive silver (Ag) traces on electrode patterns and multiple substrates (SiO2, Kapton, mica). The low viscosity of the AgNP ink solution allowed write speeds up to 1600 μm/s, almost 4 orders of magnitude higher than typical thiol-on-gold DPN writing speeds. This direct-write methodology paves the way for site-specific deposition of metallic materials for use in applications such as circuit repair, sensor element functionalization, failure analysis, gas sensing, and printable electronics.