Room Temperature Synthesis of Metal Chalcogenides in Ethylenediamine.

Reaction of sulfur and selenium with elemental or ionic metals in liquid ethylenediamine at room temperature produced metal chalcogenides ME (M = Cu, Sn, Co(2+), Ni(2+), Mn(2+), or Pb(2+); E = S or Se), Ag(2)E, M(2)E(3) (M = Bi or Sb). The results showed that the products had a range of crystalline sizes from 10 to 100 nm. Some reactions produced molecular precursors. Heat treatment of these precursors at 250 degrees C under a N(2) atmosphere induced crystalline chalcogenides. The pre- and postheated metal chalcogenides were analyzed by X-ray diffraction (XRD). Some key compounds are analyzed by X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The roles of ethylenediamine in the reaction system are also discussed in this report.