Hydrothermal synthesis, structures and luminescent properties of nanocrystaline Ca8Gd2(PO4)6O2:Eu2+, Eu3+ phosphors

• Ca8Gd2(PO4)6O2:Eu2+, Eu3+ ultrafine nanorods are prepared by a hydrothermal method.
• Ammonia and EDTA play a key role in the formation of nanorods.
• The effect of EDTA on the nanorod morphology is investigated.
• Eu ions from Ca2+ and Gd3+ sites emit the bluish-green and red colors, respectively.
• Nanorods exhibit hydrophilic nature, which is a basic requirement for bio applications.

Oxyapatite Ca8Gd2(PO4)6O2 (CGP):Eu2+, Eu3+ ultrafine nanorods were synthesized by a facile hydrothermal method. The effect of experimental conditions such as reaction time and concentration of ethylenediaminetetraacetic acid (EDTA) on the morphology of the nanomaterials was investigated. The structural properties were analyzed using the X-ray diffraction patterns, which confirm the hexagonal phase with space group P63/m. The pure hexagonal phase of CGP appeared without calcining in both non-EDTA and EDTA cases. The photoluminescence emission spectra of Eu ions activated CGP nanorods showed a broad bluish-green emitting band centered at 488 nm when doped in the Ca2+ sites while they showed a dominant red emission at 618 nm when doped in the Gd3+ site. These phosphors can be excited by near ultraviolet and visible light sources, which might be a promising material for the development of biomaterials due to its hydrophilic nature and white light-emitting diodes because of their rich emission properties.