The influence of capping thioalkyl acid on the growth and photoluminescence efficiency of CdTe and CdSe quantum dots

Abstract

The influence of thioalkyl acid ligand was evaluated during aqueous synthesis at 100 °C and under hydrothermal conditions (150 °C) of CdTe and CdSe quantum dots (QDs). Experiments performed with 3-mercaptopropionic acid (MPA), 6-mercaptohexanoic acid (MHA) and 11-mercaptoundecanoic acid (MUA) demonstrated that the use of MHA and MUA allowed for the preparation of very small nanoparticles (0.6-2.5 nm) in carrying out the reaction under atmospheric pressure or in an autoclave and that the photophysical properties of QDs were dependent on the ligand and on the synthesis conditions. The influence of various experimental conditions, including the Te-to-Cd ratio, temperature, and precursor concentration, on the growth rate of CdTe or CdSe QDs has been systematically investigated. The fluorescence intensities of CdTe QDs capped with MPA, MHA, or MUA versus pH were also found to be related to the surface coverage of the nanoparticles.

Enhanced Photostability from CdSe(S)/ZnO Core/Shell Quantum Dots and Their Use in Biolabeling

“…Se 2-addition to a growing QD surface. The CdSe(S)/ZnO core/shell QDs were prepared by the slow injection of a 0.01 m aqueous solution of Zn(OAc) 2 to the crude CdSe(S) QDs under atmospheric pressure and by further heating at reflux for 2 h. At basic pH [the pH value measured at the end of the hydrothermal synthesis of CdSe(S) QDs was found to be 10.9], Zn(OAc) 2 is first hy- In comparison with the spectrum for the syntheses conducted under normal pressure at 100°C, [14] the PL spectrum of the CdSe(S) cores does not show a shallow trap emission because of incomplete passivation. The luminescence of MPA-capped CdSe(S) QDs is dominated by near-band-edge luminescence at 511 nm (PL quantum yield of 13 %).…”

Impairments of spatial learning and memory following intrahippocampal injection in rats of 3-mercaptopropionic acid-modified CdTe quantum dots and molecular mechanisms

“…8,48,49 Given that the dose-and size-effect relationship of MPA-modified CdTe QDs has been investigated here, the role of functionalized ligand MPA should be investigated in further studies, as well as other key molecular targets.…”

Synthesis of Glutathione Coated Quantum Dots

“…These defects can be eliminated by the selection of capping agents. The process of functionalization involves ligand exchange with thioalkyl acids such as thioglycolic acid (TGA) (Xu et al 2008), mercaptoacetic acid (MAA) (Abd El-sadek et al 2011), mercaptopropionic acid (MPA) (Cui et al 2007), mercaptoundecanoic acid (MUA) (Aldeek et al 2008), mercaptosuccinic acid (MSA) (Huang et al 2007) or reduced GSH.…”