Morphological growth and phase formation of CuInSe2nanocrystals by an ambient pressure polylol-based solution synthesis

Abstract

Single-phase and well-dispersed CuInSe₂ nanoparticles and nanoplates were successfully synthesized through an ambient pressure solution chemical process using green triethylene glycol (TEG) as solvent, copper(II) chloride, indium(III) chloride and selenium powder as precursor sources. Morphological growth of the CuInSe₂ nanoparticles and nanoplates synthesized respectively with the hydrazine- and ethylenediamine-assisted TEG reaction solution was investigated by XRD, TEM, HRTEM, SAED, XPS and EDX analysis. The results showed that the growth process of CuInSe₂ nanoparticles derived from the hydrazine-assisted solution only underwent quick reduction reaction of elemental Se to Se²⁻ and cupric Cu²⁺ to Cu⁺ to directly form the ternary compound. The growth of CuInSe₂ nanoplates derived from the ethylenediamine-assisted solution involved in the formation of intermediate phase CuSe with lamellar morphology and subsequently a transformation of the CuSe phase into CuInSe₂ phase by gradual reduction of cupric Cu²⁺ to cuprous Cu⁺, In³⁺ and active Se²⁻ participation at growing lattice sites.