Near-infrared light induced curing of electrically conductive adhesive assisted by upconversion particles

Abstract

In this work, the upconversion nanoparticle-assisted near infrared photopolymerization (UCAP) technology was used to cure an electrically conductive adhesive (ECA) with excellent conductivity and shear strength for the first time. Silver coated copper particles, epoxy acrylic resin and a reactive monomer were mixed with upconversion nanoparticles (UCNPs) and a photoinitiator to prepare the ECA. With the assistance of upconversion nanoparticles, near-infrared (NIR) light was converted into UV light inducing the photo-curing of the ECA. In the meantime, the photo-thermal effect of NIR light rapidly increased the temperature of the system to initiate the thermal-curing of the ECA, and no additional heating was required. The synergistic effect of photo-curing and thermal-curing during the UCAP process resulted in a sufficient curing of the ECA, which solved the problem of the incomplete UV-curing of the ECA. In addition, the photo-curing and thermal-curing processes were carried out almost concurrently and the whole process could be accomplished in several minutes, which is really highly efficient, green and energy-saving.