Synthesis of CuInGaSe₂ nanoparticles by low temperature colloidal route

Abstract

CIGS nanoparticles were synthesized by a low temperature colloidal route for the absorber layer of photovoltaic devices. The CIGS nanoparticles were prepared by reacting CuI, InI₃, GaI₃ in pyridine with Na₂Se in methanol at 0°C under inert atmosphere. The reaction products of dark red and yellow colors were turned out to be NaI and CIGS nanoparticles, respectively, by ICP-AES and SEM-EDS analyses. Chalcopyrite structure of the CIGS nanoparticles was confirmed by XRD and TEM diffraction patterns. As compared to the particles from Cu_0.9In_0.8 Ga_0.3Se₂ ratio, more uniform and smaller nanoparticles were obtained from Cu_1.1In_0.68Ga_0.23Se_1.91 stoichiometric ratio. The CIGS nanoparticles were measured to be in the ranges of 5-20 nm. However, tube like CIGS particles with length of several γn and width in the range of 100-300 nm were obtained from Cu_0.9In_0.8Ga_0.3Se₂, and Cu_0.9In_0.7Ga_0.4Se₂. The morphological change of the CIGS particles seems to be closely related to the ratio of Cu/(In+Ga).