Surface passivated aqueous mediated synthesis of CdTe QDs: potential nano thin films

Abstract

Cadmium Telluride (CdTe) semiconductor quantum dots (QDs) have potential applications in optoelectronics, biomedical and photovoltaic solar cells. In spite of having tremendous potentiality in the applied fields, the literature reveals scanty reports about the low cost, environmentally sustainable and ambient temperature methodology for the synthesis of CdTe QDs. Currently, the aqueous synthesis route is more promising due to its more reproducibility, less toxicity and biocompatibility. However, the reported aqueous methods also find defect associated photoluminescence due to the presence of surface trap states, which diminish luminescence property drastically with red-shift emission. The present work reportssynthesis of surface passivated FCC cubic crystalline CdTe QDs (size ∼4–7 nm from x-ray diffraction and transmission electron microscopic techniques) in an atom economic greener way, where Polyvinylpyrollidone is acting as capping agent. Polyvinylpyrollidone effectively passivates the surface of QDs by quenching surface dangling bonds, which is proved by photoluminescence investigation with quality single band edge emission at 500 nm (λex = 335 nm, Eg = 2.48 eV). The characterized CdTe nanomaterials were subjected to the fabrication of thin films by simple and cost-effective spin coating method.