Solvent interface effect on the size and crystalline nature of the GdPO₄:Eu³⁺ nanorods

Abstract GdPO₄:Eu³⁺ nanorods (~20 nm) were synthesized by a facile hydrothermal technique based on the water/2-PrOH interface. The size of nanorods was controlled by varying the reaction temperature and solvent interface. After calcination at 700°C, the hexagonal phase of as-prepared GdPO₄·H₂O:Eu³⁺ nanorods was transformed into the monoclinic phase, which was confirmed by XRD patterns and TEM images. During the calcination process, along with the phase transformation, the size of nanorods was also shortened by the removal of H₂O molecules from the lattice. Photoluminescence (PL) excitation spectra revealed the efficient energy transfer between Gd³⁺ and Eu³⁺ ions and the orange-red emission was typically observed from PL spectra because the Eu³⁺ ions exist with inversion symmetry in the lattice. Also, these GdPO₄:Eu³⁺ nanorods were highly dispersible in water.