Investigations of Ce³⁺ Co-Doped SbPO₄:Tb³⁺ Nano-Ribbons and Nanoparticles by Vibrational and Photoluminescence Spectroscopy

Nano-ribbons and very small nanoparticles (size 2–5 nm) of SbPO₄ doped with lanthanide ions (Ce³⁺ and Tb³⁺) are prepared at a relatively low temperature of 120 °C based on a solution method. Detailed vibrational and luminescence studies on these samples establish that these lanthanide ions are incorporated at Sb³⁺ site of the SbPO₄ lattice. The excitation spectrum corresponding to the Tb³⁺ emission and the excited state lifetime of the ⁵D₄ level of Tb³⁺ ions in the sample confirm the energy transfer from Ce³⁺ to Tb³⁺ ions in the SbPO₄ host. The extent of energy transfer from Ce³⁺ to Tb³⁺ in these samples is found to be around 60%. Dispersion of these nanomaterials in silica matrix effectively shields the lanthanide ions at the surface of the nano-ribbons/nanoparticles from the stabilizing ligands resulting in the reduction in the vibronic quenching of the excited state. Our results show significant reduction in the surface contribution in the decay curve corresponding to the ⁵D₄ level of the Tb³⁺ ions after incorporating the nano-ribbons/nanoparticles in silica. These nanomaterials incorporated in silica matrix can have potential applications in bio-assays and bio-imaging.