More Like this

1. Release, detection and toxicity of fragments generated during artificial accelerated weathering of CdSe/ZnS and CdSe quantum dot polymer composites

   https://doi.org/10.1039/C8EN00249E  

   Gallagher, Miranda J. ; Buchman, Joseph T. ; Qiu, Tian A. ; Zhi, Bo ; Lyons, Taeyjuana Y. ; Landy, Kaitlin M. ; Rosenzweig, Zeev ; Haynes, Christy L. ; Fairbrother, D. Howard ( January 2018 , Environmental Science: Nano)

   Next generation displays and lighting applications are increasingly using inorganic quantum dots (QDs) embedded in polymer matrices to impart bright and tunable emission properties. The toxicity of some heavy metals present in commercial QDs ( e.g. cadmium) has, however, raised concerns about the potential for QDs embedded in polymer matrices to be released during the manufacture, use, and end-of-life phases of the material. One important potential release scenario that polymer composites can experience in the environment is photochemically induced matrix degradation. This process is not well understood at the molecular level. To study this process, the effect of an artificially accelerated weathering process on QD–polymer nanocomposites has been explored by subjecting CdSe and CdSe/ZnS QDs embedded in poly(methyl methacrylate) (PMMA) to UVC irradiation in aqueous media. Significant matrix degradation of QD–PMMA was observed along with measurable mass loss, yellowing of the nanocomposites, and a loss of QD fluorescence. While ICP-MS identified the release of ions, confocal laser scanning microscopy and dark-field hyperspectral imaging were shown to be effective analytical techniques for revealing that QD-containing polymer fragments were also released into aqueous media due to matrix degradation. Viability experiments, which were conducted with Shewanella oneidensis MR-1, showed a statistically significant decrease in bacterial viability when the bacteria were exposed to highly degraded QD-containing polymer fragments. Results from this study highlight the need to quantify not only the extent of nanoparticle release from a polymer nanocomposite but also to determine the form of the released nanoparticles ( e.g. ions or polymer fragments). 

   more » « less
2. The shell thickness and surface passivation dependence of fluorescence decay kinetics in CdSe/ZnS core-shell and CdSe core colloidal quantum dots

   https://doi.org/10.1016/j.jlumin.2017.08.024  

   Rajapaksha, Ruwini D. ; Ranasinghe, Mahinda I. ( December 2017 , Journal of Luminescence)
3. Quantification of the Photon Absorption, Scattering, and On-Resonance Emission Properties of CdSe/CdS Core/Shell Quantum Dots: Effect of Shell Geometry and Volumes

   https://doi.org/10.1021/acs.analchem.0c00016  

   Xu, Joanna Xiuzhu ; Yuan, Yucheng ; Liu, Muqiong ; Zou, Shengli ; Chen, Ou ; Zhang, Dongmao ( April 2020 , Analytical Chemistry)
4. Optimizing Electron Transfer from CdSe QDs to Hydrogenase for Photocatalytic H 2 Production

   https://doi.org/10.1039/C9CC01150A  

   Sanchez, Monica Kiewit ; Wu, Chang-hao ; Adams, Michael W ; Dyer, Richard Brian ( January 2019 , Chemical Communications)

   A series of viologen related redox mediators of varying reduction potential has been characterized and their utility as electron shuttles between CdSe quantum dots and hydrogenase enzyme has been demonstrated. Tuning the mediator LUMO energy optimizes peformance of this hybrid photocatalytic system by balancing electron transfer rates of the shuttle 

   more » « less
5. Thermally activated delayed photoluminescence from pyrenyl-functionalized CdSe quantum dots

   https://doi.org/10.1038/nchem.2906  

   Mongin, Cédric ; Moroz, Pavel ; Zamkov, Mikhail ; Castellano, Felix N. ( February 2018 , Nature Chemistry)