Rapid synthesis of Tb 3+ -doped gadolinium oxyhydroxide and oxide green phosphors and their biological behaviour

Green phosphors based on terbium doped GdOOH and Gd 2 O 3 powders are prepared through a rapid microwave-assisted solution based method using ethanol as a solvent and without using anysurfactants. The as-prepared Tb 3+ :GdOOH powders are crystalline and show a flower-like morphology comprising many two-dimensional flake-like structures. The as-prepared powders show good luminescence properties under UV excitation and their conversion to Tb 3+ :Gd 2 O 3 by annealing takes place at modest temperatures. A considerable increase in luminescence intensity is observed for the annealed powders, which is ascribed to phase change from oxyhydroxide to oxide as well as an increase in crystallinity as a result of annealing. Cytotoxicity studies reveal that the as-prepared powders show considerable toxicity towards the cells, whereas the annealed powders do not hamper the cell growth.