In situ fabrication of photocurable conductive adhesives with silver nano-particles in the absence of capping agent

To increase electrical conductivity and reduce number of processes, this paper aims to fabricate in situ photocurable conductive adhesives with Ag nano-particles in the absence of polymeric protector. The mixture of epoxy–acrylic resin and reactive monomer, as well as AgNO3 in ethylene glycol, is irradiated by UV light to form silver nano-particles without capping agent and was followed by adding photoinitiator to produce photocurable adhesive with silver nano-particles. In particular, as measured by transmission electron microscopy, the diameter of Ag nano-particle is 30–50 nm for 1 M and 80–90 nm for 2 and 3 M of AgNO3, in ethylene glycol. Furthermore, taking 1:1 weight ratio of photosensitive mixture to 3 M of AgNO3 in ethylene glycol as an example, the surface electrical resistivity of photocurable conductive adhesive may be reduced to 8.803×106 (Ω/□) after exposing to 900 mJ/cm2.