Structural and Optical Study of Ga³⁺ Substitution in CuInS₂ Nanoparticles Synthesized by a One-Pot Facile Method

Abstract

A one-pot method was used to synthesize CuIn x Ga 1– x S 2 nanoparticles by substituting In 3+ with Ga 3+ . The samples with composition of gallium ranging from 0% to 100% were synthesized by solving copper chloride, indium trichloride, gallium acetylacetonate, and thiourea as precursors in 1-octadecene, oleylamine, and oleic acid as noncoordinating, coordinating, and capping agent solvents, respectively. Depending on the chemical composition and synthesis conditions, the morphology of the as-synthesized nanoparticles obtained was trigonal, semitrigonal, hexagonal, and quasi-spherical. X-ray photoelectron spectroscopy and X-ray diffraction confirmed that Ga 3+ substituted In 3+ without any segregation over a wide range. The as-synthesized CuIn x Ga 1– x S 2 nanoparticles showed narrow size distribution across the entire composition range ( x = 0–1) and band gap tuned in the range from 1.44 to 2.28 eV. The morphology, structure, and optical properties of the synthesized nanoparticles were characterized using transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), UV–visible (UV–vis) spectroscopy, and X-ray photoelectron spectroscopy (XPS). The mechanism of complex formation up to nanoparticle synthesis was also discussed.