|
CuI nanocrystals were formed by attrition of Cu and I at ambient
temperature. They were characterized by XRD to be zincblende, g -CuI with an
average particle size of 20 - 40 nm. The crystallographic phase transitions from
zincblende (g -phase)-to-distorted wurtzite (b -phase)-to-disordered zincblende
(a -phase) were also investigated through non-isothermal DSC. Transition
temperatures, enthalpies and entropies of these two-phase transitions as well as
their "activation energies" were obtained, treating the phase transitions as
"reactions". It is inferred that attrition imparts a partial cation disorder
into CuI, unlike a wet chemical reaction. Attrition essentially prepares the fcc
Cu lattice for accommodation of I ions in a weakly covalent arrangement.
|