Molecular sensitized GdF3:Eu3+ for color tuning and highly enhanced luminescent properties.

In this work, we report on the preparation of [2,3-f]pyrazino[1,10]phenanthroline-2,3-dicarboxylic anions (PPDB(2-)) modified GdF3:Eu(3+) nanocrystals by a versatile ligand exchange approach for highly enhanced luminescent properties. The samples were carefully characterized by X-ray powder diffraction, transmission electron microscopy, infrared spectra and photoluminescence. It is found that all GdF3:Eu(3+) nanoparticles were entirely composed of homogeneous nano-spheres with an average diameter of about 30-35 nm. After PPDB(2-) capping, GdF3:Eu(3+) nanocrystals exhibited higher color purity and shorter lifetime time, which can be well recognized as a consequence of surface structure modification and local symmetry alteration near Eu(3+) ions. High color purity and short lifetime of PPDB(2-) modified GdF3:Eu(3+) nanocrystals predict highly enhanced red luminescence, which showed the quantum efficiency of ~34%. The highly enhanced luminescent property enables its potential application as chemosensor for detection of heavy metal ions.