The hydrothermal synthesis of ultra-high aspect ratio Ag nanoflakes and their performance as conductive fillers in heaters and pastes

Abstract

Ag nanoflakes with a size ranging from 5 to 60 μm, a thickness of several tens of nanometers and an aspect ratio of up to 800 have been synthesized via a hydrothermal method. PVP was used as both a surfactant, inducing anisotropic growth of the Ag nanoflakes, and as a reductant, reducing Ag⁺ to Ag. An Ag–oxalate complex was used as a precursor, allowing effective control of the kinetic growth of the Ag nanoflakes. Influences on the size and morphology of the Ag nanoflakes, such as H⁺ concentration and reaction time, were discussed and analyzed. Our method can be easily scaled up for mass production. A large interfacial contact area between the Ag nanoflakes with more electrical channels makes the Ag nanoflakes excellent conductive fillers.