Sulfur-free synthesis of size tunable rickardite (Cu Te) spheroids and planar squares.

We report a novel synthesis of monodisperse samples of copper telluride with crystallinity and stoichiometry corresponding to forms of rickardite, Cu Te ( < 1). This synthesis makes use of a ligand balanced reaction to allow control over shape and size by varying the relative and absolute concentration of oleylamine to stearic acid. The rickardite samples presented here display size dependent plasmon peaks in the near infrared and direct energy band gaps between 1.7 and 2.3 eV. As such they may find utility in photovoltaic, thermoelectric or as novel optical materials for study of surface plasmons.