Surfactant-based synthesis of optically active colloidal GdF3:Ce3+(5%), Eu3+(x%) and GdF3:Ce3+(5%), Eu3+(5%)/SiO2 phosphor nanocomposites

The synthesis of water dispersible phosphor materials is important due to the possibility of their applications in sensors, bioimaging, magnetic resonance imaging (MRI), etc. Surfactants are in use for the controlled size synthesis of nanomaterials as well as for tuning the dispersibility of colloidal particles in different solvents. In this study, we exploited cetrimonium bromide (CTAB) with pre-added lanthanide ions or with "so called modified counterions" for the synthesis of water dispersible phosphor materials. Colloidal GdF3:Ce3+(5%)(,) Eu3+(x%) (where x is 1, 3, 5 and 7% Eu+3) and GdF3:Ce3+(5%)(,) Eu3+(5%)/SiO2 phosphor nanocomposites were synthesized. Initially, cationic CTAB system was altered by pre-adding selected lanthanides required for synthesizing phosphors as well as silica-phosphor nanocomposite. Later, the same modified CTABs were used for single step synthesis of nanoparticles as well as nanocomposites. The elemental and structural characterizations were performed using x-ray photoelectron spectroscopy (XPS), and powder x-ray diffraction (XRD) techniques. The size and morphology of the samples were checked using a transmission electron microscope (TEM). The photoluminescence (PL) properties were explored using a spectrofluorometer, and the results established the formation of phosphor nanocomposite. The method expanded the possibilities of size and shape control in for phosphor materials. Furthermore, the study offered a way to decrease the use of lanthanide while keeping the phosphor's overall properties intact. The results shown that this study can pave an alternate way for the synthesis of nano-sized structures of GdF3: Ce3+(5%) Eu3+(x%) and also for size and shape control in GdF3: Ce3+(5%) Eu3+(x%)/SiO2 type nanocomposites.