Upcoming Colloquia

Optical Spectroscopy of Individual Nanocrystal Quantum Dots

Han Htoon

Softmatter Nanotechnology and Advanced Spectroscopy,
Los Alamos National Laboratory,
Los Alamos, New Mexico 87545, USA

Monday, March 22, 10am

Chemistry Division Auditorium, TA-46, Bld. 535, Rm. 103


Optical spectroscopy has been an indispensable tool in probing fundamental photophysics of nanoscale materials. Conventional optical spectroscopy approaches that usually require sampling hundreds to thousands of individual nano-objects, are effective only in measuring averaged characteristics of an ensemble. As a result, these approaches are incapable of probing variations in optical characteristics that result from strong quantum confinement effects in different individual nanostructures. Furthermore, they are also powerless in probing electronic fine structures with energy splittings smaller than the inhomogeneously broadened ensemble spectral features. Here I will review single nanostructure optical spectroscopy approaches that are designed to overcome these problems of ensemble averaging. Specifically I will review how single NQD photoluminescence (PL) imaging, low temperature PL and magnetoPL, PL excitation and time resolved PL techniques help attain a profound understanding on the fine structure of band-edge exciton states as well as the competition between radiative and non-radiative processes.