Synthesis and characterization of CdTe quantum dots by one-step method

Abstract

L-Cysteine (Cys)-capped CdTe quantum dots (QDs) were prepared when sodium tellurite worked as a tellurium source and sodium borohydride acted as a reductant. The influences of various experimental variables, including pH values, Cd/Te and Cd/Cys molar ratios, on the photoluminescence (PL) quantum yield (QY) of the obtained CdTe QDs have been systematically investigated. Experimental results indicated that green to red emitting CdTe QDs with maximum quantum yield of 19.4% can be prepared at pH 11.5 and n_(Cd²⁺₎:n_(Te²⁻₎:n_(Cys) = 1:0.07:2.0. X-Ray powder diffraction (XRD) and transmission electron microscopy (TEM) were used to characterize the crystal structure and shape of CdTe QDs. The results showed that the prepared CdTe QDs were of cubic zinc blend crystal structure in a sphere-like shape.

KEY WORDS: Semicondutor nanocrystal, Chemical synthesis, Optical properties, Luminescence

Bull. Chem. Soc. Ethiop. 2013, 27(3), 387-393.

DOI: http://dx.doi.org/10.4314/bcse.v27i3.7