Synthesis and Characterization of Thiol-Stabilized CdTe, CdSe Nanocrystals by a Modified Hydrothermal Method

Abstract

A modified method to prepare high-quality thiol-stabilized CdTe and CdSe nanocrystals (NCs) was reported in this paper. The experimental results showed that the PL properties of the CdTe NCs were strongly dependent on the initial TGA-to-cadmium ratio and concentration of the precursors in the solution. When the concentration of Cd <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2+</sup> was 6mM and [TGA]/[Cd <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2+</sup> ] was 2.4, the high reactivity of the monomers resulted in generating a large amount of nanoparticles in the nucleation stage, in favor of the reconstruction and optimum surface NCs in the following growth. Using lower concentration ([Cd <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2+</sup> ]=2mM) of precursors, this aqueous synthesis of thiol-stabilized CdTe NCs provided lower reaction yields, the optimum properties of NCs were obtained when [TGA]/[Cd <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2+</sup> ] was 1.2. In addition, CdSe NCs with the maximum PL QY of approximately 16% can be obtained with Na <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> SeSO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> as Se precursor instead of NaHSe.