Synthesis of ZnS, CdS and Core-Shell Mixed CdS/ZnS, ZnS/CdS Nanocrystals in Tapioca Starch Matrix

Abstract

Gel of tapioca starch (TS) is a suitable matrix for the formation of ZnS, CdS and core-shell ZnS/CdS as well as CdS/ZnS quantum dots (QDs). These QDs reside in the matrix as non-agglomerating 3 - 10 nm nanocrystals. It is demonstrated that amylopectin is responsible for the QDs formation rather than amylose. Combination of ZnS with CdS in the core-shell QDs results in the increase in the intensity of emission without any shift of its wavelength.