Executive Summary : | Although these MNCs are considered to be the next generation fluorophores, and are characterized by large Stokes shift, water solubility and excellent biocompatibility, yet there are a few severe limitations related to these MNCs as underlined below: (i) Generally, the stability of MNCs is low and this requires several iterations and optimizations of the synthetic protocols. (ii) Besides the smaller nanoclusters, the synthetic procedure often leads to larger sized metal nanoparticles which are mostly non-luminescent in nature. (iii) The photo-luminescence quantum yield (PLQY) is generally low which limits their applications, especially for investigations related to single molecule spectroscopy. (iv) The photostability of the MNCs is sometimes not very promising which again makes them not that suitable specially when luminescent properties have to be monitored over prolonged period of time. Hence, to address these shortcomings and use these MNCs for investigations involving both ensemble average and single molecule spectroscopy, several strategies have been employed. These involve aggregation induced emission, capped-ligand engineering, fine tuning the synthetic protocols, metallic kernel alloying etc. In this proposal, we intend to address the following objectives: * How to maximize the photoluminescence quantum yields (PLQY) and photostability of the MNCs once they are produced. * Use the electronic effects of surface ligands to modify the spectroscopic signatures of the MNCs. * Establish the role of oxidation states of the concerned metal in the MNC core and correlate the same with the spectroscopic properties and stability therein. * Explore the possibilities of white light emission and establish their role in preliminary device fabrication mainly related to LEDs. * Investigate the role of the MNCs in catalytic reactions. * Explore the role of these MNCs to serve as a molecular probe (mainly as a FRET pair) to study dynamics within complex biological environments using both ensemble average and single molecule spectroscopic investigations. * Using Fluorescence Correlation Spectroscopy (FCS) and Fluorescence Lifetime Imaging Microscopy (FLIM) to monitor the dynamics inside live cells. |