Growth and characterization of CuInS2 nanoparticles prepared using sonochemical synthesis

• CuInS2 nanoparticles were synthesized using the sonochemical method.
• Samples are the tetragonal CuInS2 with an average diameter between 9.2 and 14.8 nm.
• Samples with [Cu]/[Cu+In] molar ratio greater than 0.50 were p-type semiconductors.
• The conversion efficiency of thin-film solar cell was around 1% under illumination.

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 9.2–14.8 nm. 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 × 1015 cm−3 and 2.13–59.0 cm2 V−1 s−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 100 mW/cm2.