Effect of Silver Nanowires on the Resistivity of Electronically Conductive Adhesives

Large-scale silver nanowires with a length of 30∼90 μm were synthesized by a polyol process. Electronically conductive adhesives (ECAs) were made by adding micro-sized silver flakes and silver nanowires to the polymer composites consisting mainly of epoxy resin, cure agent and catalyst. The volume resistivity of the ECAs was researched as a function of silver filling loading and sintering temperature. The results indicate that the volume resistivity of ECAs first decreases and then increases with the increase of fractions of silver nanowires when the curing temperature is 180 °C. With the increase of curing temperature, the volume resistivity of ECAs decreases. In the condition of the ECAs filled with 65% silver fillers (the ratio of silver micro-sized silver flakes and silver nanowires is 55:10), the volume resistivity of ECAs reaches 6.5×10−4 and 1.3×10−4 Ω·cm when cured at 180 and 300 °C, respectively. The dramatic improvement in the conductivity of the ECAs is due to the low-temperature sintering of the silver nanowires at 300 °C. Effect of silver nanowires on the resistivity of ECAs was discussed in terms of the distribution and sintering behavior of silver nanowires and interaction relationship between silver nanowires and micro-sized silver flakes.