Hydrothermal processes for Tm3+ -doped GdV O4 nanocrystalline morphologies and their photoluminescence properties

Controlled reaction conditions in simple, template-free hydrothermal processes yield pure tetragonal zircon-type I41/amd TmGdV O4 nanocrystals with well-defined specific morphologies and sizes. Nitrate reagents under mild conditions (180 ∘C, pH=7, autogenous pressure) produce from square, hexagon and lozenge nanocrystals with sides starting in 20 nm, to porous spindles, nanotubes, nanorods and nanobelts depending of the reaction times. They exhibit photoluminescence in ∼1.95 μm similar to bulk single crystals. For the lowest Tm3+ concentration (0.2 % mol) in GdV O4 measured 3H4 and 3F4 fluorescence lifetimes τ are very near to their radiative values, τrad.