Deep crystallization induced high thermal conductivity of low-temperature sintered Ag nanoparticles

We studied the mechanism and morphological evolution of a thermal interface material prepared by pressureless sintering of a paste containing silver nanoparticles (Ag NPs) flocculated with citrate or nitrate. A high thermal conductivity (>100 W/K-m) was obtained from the material sintered at 453 K for 30 min. Significant crystallization and large amounts of twins were observed in the material. These results could be ascribed to the thinner organic shells surrounded the Ag NPs, resulting in easy activation of Ostwald ripening.