Hexagonal phase into Au plate-like particles: A precession electron diffraction study

Abstract

Crystalline defects can play a role in explaining speculative crystal growth mechanisms. Nevertheless, these structural features are commonly out of range for conventional diffraction characterizations. Particularly, defects in Au nanoplates (NPs) have attracted attention over the last 40 years due to the so called 1/3{422} “Forbidden Reflections” (FR). This work ends with the discussion of nanoplate defects by performing large angle tilting experiments in Transmission Electron Microscope (TEM) using several imaging techniques such as: bright/dark field (BF/DF) and the advanced Precession Electron Diffraction (PED) technique. Obtained results can relate FR with a hexagonal Au phase, presenting for the first time two hexagonal diffraction patterns on 112¯3 and 51¯4¯3¯ zone axes. This hexagonal-fcc interface is located inside of plate particles and has a hexagonal phase with a = 0.2870 nm and c = 0.7351 nm lattice parameters.