Tunable Fluorescence Emission and Efficient Energy Transfer in Doped Organic Nanoparticles

Luminescent organic nanoparticles consisting of a green-emitting ESIPT compound DHBIA doped with a red-emitting dye MAFN have been prepared by the reprecipitation method. It was found that emission of nanoparticles can be tuned gradually from green to red by increasing doping levels. These nanoparticles could be analyzed as a system of densely packed chromophores that showed efficient energy transfer from DHBIA to MAFN. The energy transfer in these systems was assigned to the Förster resonance mechanism. A simple model was modified and used to analyze quantitatively this energy transfer behavior in doped nanoparticles. The bathochromic of guest emission was presumably due to solid state solvation effects (SSSE).