Growth Kinetics of Zinc Sulphide Nanocrystals Synthesized by Colloidal Thermolysis of Fatty Acid Carboxylates

Abstract

Zinc sulphide (ZnS) is an important semiconductor with widespread electronic and catalytic applications. The growth kinetics of ZnS nanocrystals synthesized by the thermal decomposition of zinc ricinoleate carboxylates in an oleylamine:dodecanethiol (1: 1) solvent mixture isreported. Crystalline sphalerite ZnS nanocrystals with quantum dot sizes of 2.3-5.3 nm were obtained at temperatures higher than 240°C. The p-XRD patterns showed a clear relationship between the crystallite sizes and the peak broadness at a temperature range of 250-300°C. The optical bandgap energies of the ZnS nanocrystals reduced from 4.27 eV to 3.73 eV as the time of reaction increased from 20 to 60 min at 250°C. The activation energy for the growth kinetics of the ZnS nanocrystals was determined to be 36.24 kJ/mol which compares closely to those reported in the literature for aqueous systems.