Fluorescent polyelectrolyte capped silver nanoclusters: Optimization and spectroscopic evaluation

In the present Letter, we have synthesized water soluble Ag nanoclusters using PMAA as a template with different Ag+:COO− ratios, to optimize it for highest brightness using less UV exposure time. Fluorescence polarization was 0.30 and was found to vary with excitation and emission wavelength with few hundred picoseconds average fluorescence lifetime. Fluorescence correlation spectroscopy data depicts slower diffusion at red excitation compared to blue excitation in confocal volume than conventionally synthesized colloids proving presence of multiple sizes. The optical properties of the particles are dependent upon the excitation wavelength used and the emission wavelength collected.