SINSLIM · Smart Inorganic Nanocrystals for Sub-diffraction Limited IMaging

The goal of this proposal is to design and fabricate ""smart"" inorganic fluorophores, which could replace to replace currently used organic dyes for far-field sub-diffraction limited microscopy applications. Delicate band-gap engineering of the structure and composition of colloidal semiconductor nanocrystals is suggested as a path to achieving the required nonlinear all-optical control over their luminescent properties. In conjunction with the inherent photostability, tunability and ease of excitation of these nanocrystals, this can pave the way towards greatly simplified instrumentation and techniques, implying dramatically reduced costs and significantly broader accessibility to sub-diffraction limited imaging.The proposed research is a concerted effort both on colloidal synthesis of complex multicomponent semiconductor nanocrystals and on time and frequency resolved photophysical studies down to the single nanocrystal level. Several schemes for photoactivation and reversible photobleaching of designed nanocrystals, where the localization regime of excited carriers differs between the electrons and the holes, will be explored. These include effective ionization of the emitting nanocrystal core and optical pumping of two-color emitting QDs to a single emitting state. Fulfilling the optical and material requirements from this type of system, including photostability, control of intra-nanocrystal charge- and energy-transfer processes, and a large quantum yield, will inevitably reveal some of the fundamental properties of the unique system of strongly coupled quantum dots in a single nanocrystal.""