"Room-temperature stabilization of nanoscale superionic Ag2Se"

T Hu: J S Wittenberg and A M Lindenberg; Nanotechnology, 09/24/14.

Additional Authors: J S Wittenberg and A M Lindenberg

Abstract:

Superionic materials are multi-component solids in which one sub-lattice exhibits high ionic conductivity within a fixed crystalline structure. This is typically associated with a structural phase transition occurring significantly above room temperature. Here, through combined temperature-resolved x-ray diffraction and differential scanning calorimetry, we map out the nanoscale size-dependence of the Ag2Se tetragonal to superionic phase transition temperature and determine the threshold size for room-temperature stabilization of superionic Ag2Se. For the first time, clear experimental evidence for such stabilization of the highly ionic conducting phase at room temperature is obtained in ~2 nm diameter spheres, which corresponds to a >100 ?C suppression of the bulk phase transition temperature. This may enable technological applications of Ag2Se in devices where high ionic conductivity at room temperature is required.