Title :

Probing Energetic and Spatiotemporal Heterogeneity using Single-Emitter Spectroscopy

Abstract :

While ensemble measurements have been extremely successful in understanding the structure and dynamics in the condensed phase, they have often failed to capture the underlying details of the physical processes which give rise to the observed “bulk” behaviors. In this context, single-molecule fluorescence microscopy has emerged as a valuable technique to extract information regarding local (nanoscale) properties in complex (disordered) systems and understand the extent of spatiotemporal as well as energetic heterogeneities therein. This presentation will exemplify the efficacy of single-emitter spectroscopy to elucidate energetic inhomogeneity in two categories of luminescent semiconductor nanocrystals (undoped and dopedquantum-dots). Further, I will discuss the utility of single-molecule translational and rotational mobility measurements to provide insights on the extent of spatial and dynamic heterogeneity in polymer thin-films during plasticization, a process which involves solvent induced lowering of the glass transition temperature.