The sculpturing effect of chloride ions on the shape transformation of silver nanoparticles is presented. UV-vis spectroscopy and transmission electron microscopy (TEM) were used to monitor the evolution of silver nanoplates. Clcan etch the corners and side faces of the silver nanoprism, and the resulting nanoparticles are disk-like in shape. The dissolved silver atoms would aggregate to form small silver clusters, which were stabilized by the Cland citrate ions. The facet-selective etching effect of Clis mainly attributed to the surface energy difference of each face of the nanoplate. The thickness of the nanodisk increased during the etching process because of the redeposition of sliver clusters on the {111} planes. The prepared nanodisk also gave rise to high SERS intensity of the probing molecule.

We study the properties of ThCr2Si2 structure BaMn2As2 and BaMn2Sb2 using density functional calculations of the electronic and magnetic as well experimental measurements on single crystal samples of BaMn2As2. These materials are local moment magnets with moderate band gap antiferromagnetic semiconducting ground states. The electronic structures show substantial Mn -pnictogen hybridization, which stabilizes an intermediate spin configuration for the nominally d 5 Mn. The results are discussed in the context of possible thermoelectric applications and the relationship with the corresponding iron / cobalt / nickel compounds Ba(Fe,Co,Ni)2As2.

No abstract