Boldizar Janko
Dept of Physics and the Institute for Theoretical Sciences, University of Notre Dame, USA
Virtually all known fluorophores exhibit mysterious episodes of emission intermittency. A remarkable feature of the phenomenon is a power-law distribution of on- and off-times observed in colloidal semiconductor quantum dots, nanorods, nanowires and some organic dyes. For nanoparticles, the resulting power law extends over an extraordinarily wide dynamic range: nine orders of magnitude in probability density and five to six orders of magnitude in time. Exponents hover about the ubiquitous value of -3/2. Dark states routinely last for tens of seconds—practically forever on quantum mechanical timescales. Despite such infinite states of darkness, the dots miraculously recover and start emitting again. Although the underlying mechanism responsible for this phenomenon remains a mystery and many questions persist, I argue that substantial theoretical progress has been made.
Friday, October 30, 2009 at 4:00 PM
Room L211, Technological Institute
Refreshments are served at 3:30 PM
Colloquim Speakers October 30th Schedule
