Colloidal synthesis of pure CuInTe2 crystallites based on the HSAB theory

Abstract

The colloidal method has extensively been used to synthesize ternary and quaternary copper sulfides and selenides. The formation pathway and the crystallization mechanism of these nanostructures have also been investigated. Although tellurides form part of the chalcogenides, little has been reported on them particularly the crystallization mechanism of these nanostructures. Herein, we report on the colloidal synthesis of CuInTe₂. Typically reaction temperatures play a vital role in the formation of colloidal nanostructures. At temperatures below 250 °C, no formation of CuInTe₂ was seen. At 250 °C formation of CuInTe₂ could be observed with formation of binary impurities. A change in the sequence in which precursors were added at 250 °C yielded pure CuInTe₂. Therefore starting with InCl₃ and elemental Te dissolved in OLA and TOP, respectively, then adding CuCl dissolved in OLA yielded a pure CuInTe₂ phase with agglomerated cubic structures. The pure CuInTe₂ crystallites had an optical band gap of 1.22 eV in comparison to 0.93 eV of the impure CuInTe₂ phase.