Synthesis and luminescence properties of reddish orthosilicate oxyapatite phosphor LiGd9(SiO4)6O2:Sm3+

A series of reddish-emitting apatite-type phosphor LiGd9(SiO4)6O2:Sm3+ was prepared by using an appropriate solid-state method. The photoluminescence (PL), photoluminescence excitation (PLE) spectra, and decay times of the samples were characterized to investigate the photoluminescence properties for application in white light-emitting diodes (w-LEDs). The photoluminescence investigations showed that LiGd9(SiO4)6O2:Sm3+ phosphor emitted reddish emission, which ascribed to the transitions of the Sm3+ from the 4G5/2 excited state to the 6H5/2, 6H7/2, and 6H9/2 states, respectively. The critical quenching concentration of Sm3+ in LiGd9(SiO4)6O2 phosphors were determined to be about 3 mol%. Moreover, the spectroscopic data and fluorescence decay dynamics indicate that the energy transfer from Gd3+ to Sm3+ ions takes place in LiGd9(SiO4)6O2: Sm3+ phosphor. All the results indicated that the LiGd9(SiO4)6O2: Sm3+ phosphor could efficiently assimilate the near ultraviolet (n-UV) light and act as a suitable warm light candidate for n-UV w-LEDs.