THE EFFECT OF TRI-SODIUM CITRATE DIHYDRATE ON MORPHOLOGICAL AND OPTICAL PROPERTIES OF TbPO4.H2O NANOPHOSPHORS

Abstract

Luminescent materials doped with rare earth ions which have advantages of high stability, non-complex fabrication, easy surface functionalization, friendly to environment have been very promising materials in biomedical applications. In this report, we present a number of results achieved of the effect of tri-sodium citrate dihydrate agents on morphology and optical properties of TbPO₄.H₂O nanophosphors. These nanophosphors were successfully synthesised using wet chemistry techniques. Morphological, structure and optical properties of TbPO₄.H₂O nanophosphors were investigated by field emission scanning electron microscopy, energy-dispersive X-ray, X-ray diffraction and photoluminescence spectroscopy. The mean size of TbPO₄.H₂O nanorods is about 50 ¸ 80 nm in diameter and 500 ¸ 800 nm in length. The presence of tri-sodium citrate dihydrate (0.1M) have changed the morphology of the nanophosphors from a rods to a rectangular form (with a length of about 100 ¸ 200 nm and a width of about 10 ¸ 30 nm) and improve the luminescent ability of the nanophosphors. The green emission spectrum of TbPO₄.H₂O nanophosphors is composed of four well-resolved peaks at 488 nm, 540 nm, 585 nm and 618 nm, which correspond to the ⁵D₄-⁷F_j (J = 6, 5, 4, 3) transitions of Tb³⁺ ions. These results show high potential application of TbPO₄.H₂O nanophosphors for the development of fluorescent labelling in biomedicine.