Synthesis of High-Quality N-Acetyl-l-Cysteine-Capped CdTe Quantum Dots by Hydrothermal Route and the Characterization through MALDI-TOF Mass Spectrometry

High-quality water-soluble N-acetyl-l-cysteine-capped CdTe quantum dots (QDs) have been synthesized through a hydrothermal route, which allows a rapid preparation time (<1 h) and tunable emitting peaks (from 535 to 650 nm) with excellent quantum yields as high as 45%. The influences of different synthetic parameters upon the growth kinetics and the quantum yields of prepared QDs have been systematically studied. The electron diffraction spectroscopy technique was employed to examine the impacts of the molar ratio of reactants and reaction time on the element compositions of prepared QDs. In particular, matrix-assisted laser desorption ionization time-of-flight mass spectrometry has been used for the first time to systematically study the sizes of CdTe QDs.