Fabrication of dual excitation, dual emission nanophosphor with broad UV and IR excitation through simultaneous doping of triple rare earth ions Er~(3+), Yb~(3+), Eu~(3+) in GdPO_4

摘要

Dual excitation, dual emission properties have been introduced in triple rare earth ion (Er~(3+), Yb~(3+), Eu~(3+)) doped nanoparticles of GdPO_4 synthesized via multiple routes such as pechini type sol-gel process (PSG), co-precipitation (CPP) and high temperature solid state reaction (SSR) method. All synthesis routes produce nanoparticles in the range of 5-10 nm. Whereas highly fluorescent monoclinic nanocrystals (～10 nm) are produced by controlled SSR, as synthesized hexagonal phase nanoparticles by CPP and PSG show less fluorescence that improves when phase transforms to monoclinic upon annealing at 1000 ℃. GdPO_4:Er~(3+), Yb~(3+), Eu~(3+) nanoparticles are simultaneously excitable by UV (250-410 nm) and IR radiation (～980 nm) and exhibits dual emission i.e., intense orange red (Eu~(3+) emission) under UV excitation and bright green (~2H_(11/2) → ~4I_(15/2) transition of Er~(3+)) and red (~4F_(9/2) → ~4I_(15/2) transition of Er~(3+)) under IR excitation. The results present successful doping of triple rare earth ions in particles of nanometer dimensions with both up and down conversion fluorescence properties that can be used as potential spectrum converter for solar cells.