Growth and characterization of CuInS₂ nanoparticles prepared using sonochemical synthesis

In this study, copper indium disulfide (CuInS₂) nanoparticles were synthesized using the sonochemical method. The structural, optical, and electrical properties of the CuInS₂ nanoparticles were investigated as a function of the [Cu]/[Cu+In] molar ratio in the precursor solution. X-ray diffraction patterns show that all samples consisted of the tetragonal CuInS₂ phase with a preferential orientation along the (112) crystal plane. With a decrease in the [Cu]/[Cu+In] molar ratio in precursor solution, the diffraction peaks slightly shifted to lower angles. Transmission electron microscopy images confirm that the samples consisted of the tetragonal CuInS₂ phase with an average diameter in the range of 9.2-14.8nm. Samples with [Cu]/[Cu+In] molar ratio greater than 0.50 were p-type semiconductors whereas those with [Cu]/[Cu+In] molar ratio of less than 0.47 were n-type semiconductors. The carrier concentrations and mobilities of the samples are in the ranges of 3.31×10¹⁸-8.16×10¹⁵cm^-3 and 2.13-59.0cm²V^-1s^-1, respectively. The conversion efficiency of a thin-film solar cell with the structure glass/Mo/CuInS₂/CdS/i-ZnO/ZnO:Al was around 1% under illumination at 100mW/cm².