Issue 25, 2013

Differential effects of β-mercaptoethanol on CdSe/ZnS and InP/ZnS quantum dots

Abstract

The small thiol β-mercaptoethanol (BME) has been used as an anti-blinking reagent for CdSe/ZnS quantum dots (QDs), although its effects on QD photoluminescence are complex. It acts as an antioxidant as well as a hole scavenger on both CdSe and CdTe, which leads to changes in emission intensity and lifetime that vary qualitatively according to BME concentration, time of incubation, and pH of the solution. Because the band edge energies of InP/ZnS are shifted from those of CdTe and CdSe, it may be expected that thiols including BME might be unable to trap holes from these QDs. In this study, we use steady-state and time-resolved emission spectroscopy with physical fitting models combined with blinking analysis to compare the effects of different concentrations of BME on CdSe/ZnS vs. InP/ZnS QDs over time. We also find excellent correspondence between simple physical model parameters and blinking off times, a finding that will be useful for all blinking studies involving semiconductor nanoparticles. BME alters blinking in InP/ZnS QDs with a single ZnS shell, but not those with double thickness shells. The effects are similar to those seen with CdSe/ZnS, despite very different effects of BME on steady-state spectra, and highly pH-dependent.

Graphical abstract: Differential effects of β-mercaptoethanol on CdSe/ZnS and InP/ZnS quantum dots

Supplementary files

Article information

Article type
Paper
Submitted
22 Jan 2013
Accepted
09 May 2013
First published
10 May 2013

Phys. Chem. Chem. Phys., 2013,15, 10418-10428

Differential effects of β-mercaptoethanol on CdSe/ZnS and InP/ZnS quantum dots

M. Georgin, L. Carlini, D. Cooper, S. E. Bradforth and J. L. Nadeau, Phys. Chem. Chem. Phys., 2013, 15, 10418 DOI: 10.1039/C3CP50311A

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