By a News Reporter-Staff News Editor at Energy Weekly News -- A new study on Quantum Dots is now available. According to news reporting from Cambridge, Massachusetts, by VerticalNews journalists, research stated, "We investigate the temperature dependence of excitonic energy migration in CdSe/ZnCdS core/shell colloidal quantum dot (QD) solids using spectrally resolved transient photoluminescence spectroscopy. In line with previous studies, we observe that as excitons hop among different energy sites within the inhomogeneously broadened QD ensemble, the photoluminescence spectrum transiently shifts toward the red."
The news correspondents obtained a quote from the research from the Massachusetts Institute of Technology, "Using shape-engineered nanocrystals having a temperature-independent radiative lifetime, the magnitude of this transient red-shift is found to vary nonmonotonically with temperature. Near room temperature, the magnitude of this transient red-shift is determined by thermal equilibrium within the site energy distribution. As the sample temperature is reduced, the site-to-site hopping rate slows down and excitons become kinetically trapped at local minima in the global energy landscape. For a more homogeneous QD ensemble, reduction in site energy disorder causes the transition from thermodynamic to kinetic-limited behavior to shift to lower temperatures."
According to the news reporters, the research concluded: "These results have implications for the design of colloidal QD optoelectronic devices and advance our understanding of exciton dynamics and energy transport in disordered systems."
For more information on this research see: Transition from Thermodynamic to Kinetic-Limited Excitonic Energy Migration in Colloidal Quantum Dot Solids. Journal of Physical Chemistry C, 2014;118(15):7894-7900. Journal of Physical Chemistry C can be contacted at: Amer Chemical Soc, 1155 16TH St, NW, Washington, DC 20036, USA. (American Chemical Society - www.acs.org; Journal of Physical Chemistry C - www.pubs.acs.org/journal/jpccck)
Our news journalists report that additional information may be obtained by contacting L.V. Poulikakos, MIT, Dept. of Chem Engn, Cambridge, MA 02139, United States. Additional authors for this research include F. Prins and W.A. Tisdale.
Keywords for this news article include: Cambridge, Quantum Dots, Massachusetts, United States, Nanotechnology, Emerging Technologies, North and Central America
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