A novel green-emitting Ni2+-doped Ca-Li hydroxyapatite nanopowders: structural, optical, and photoluminescence properties

Abstract

In recent times, novel luminescent phosphor materials have potential applications in multi-color-emitting devices and optical communications. In the present study, novel Ni2+-doped calcium-lithium hydroxyapatite (CLHA) nanopowders were successfully constructed by a facile mechanochemical synthesis. The synthesized samples were characterized by several microscopic and spectroscopic techniques. The hexagonal phase of the prepared sample was confirmed by X-ray diffraction results, and the average crystallite sizes were evaluated. The morphologies of the Ni2+-doped CLHA nanopowders were investigated by scanning electron microscopy and transmission electron microscopy investigations. Fourier transform infrared spectra demonstrated the formation of numerous vibrational modes ascribed to phosphate molecules and other hydroxyl groups. X-ray photoelectron spectroscopy analysis clearly indicates the presence of Ca, Li, P, O, and Ni elements. Optical absorption and electron paramagnetic resonance data indicated that the Ni2+ ions in the host lattice correspond to the octahedral site symmetry. Photoluminescence (PL) spectra of the Ni2+-doped CLHA nanopowders revealed strong green emission peaks. From the PL emission spectra, the chromaticity CIE parameters were evaluated, and the results indicated that the synthesized phosphor materials may be useful for lighting and display devices.