Low-cost and large-scale synthesis of CuInS2 and CuInS2/ZnS quantum dots in diesel

Abstract In this paper, we present the results of the syntheses of CuInS 2 (CIS) and CIS/ZnS core/shell quantum dots (QDs) by heating-up method using diesel as the high boiling-point reaction solvent. The influences of the synthesis parameters, namely the reaction temperature, growth time and the Cu:In molar ratio to the structure and optical properties of the obtained QDs were systematically investigated. CIS QDs were synthesised at the reaction temperatures of 200–230 °C for 5–45 min and the Cu:In molar ratios of 0.5:1–1.5:1. The optical characteristics from absorption and photoluminescence spectra have been used as indicators to the quality of the synthesised QDs, showing clearly that the highest quality CIS QDs were obtained at the reaction temperature of 210 °C for 15 min with the Cu:In molar ratio of 1:1. For such QDs, their mean size of 3.5 nm was determined directly from the transmission electron microscopy (TEM) image and calculated from their XRD pattern.