Tuning the structural, optical, photoluminescence and dielectric properties of Eu super(2+)-activated mixed strontium aluminate phosphors with different rare earth co-activators

Different phosphor colors of SrAl sub(x)O sub(y): Eu sub(0.01) super(2+), R sub(0.01) super(3+) (R = Er super(3+), Tm super(3+) and Tb super(3+)) nanopowders and pellets have been synthesized via citrate combustion technique. XRD results revealed that monoclinic SrAl sub(2)O sub(4) was the major phase and hexagonal SrAl sub(12)O sub(19) was the minor phase. Meanwhile, Field emission SEM images showed hollow cylindrical-like shape structures filled with the large number of nanorods for the SrAl sub(x)O sub(y): Eu sub(0.01) super(2+), Tb sub(0.01) super(3+) sample. The values of measured band gap energy and calculated refractive index were mainly dependant on the ionic radius of R super(3+) co-doping ion. The PL emission spectra and afterglow properties were strongly affected by the lanthanide type (R super(3+)). For instance, Eu super(2+)-SrAl sub(x)O sub(y) sample achieved the maximum dielectric permittivity () ~16.77 and dielectric loss (tan delta ) ~0.19 at the microwave frequency region (1 GHz). Meanwhile, Tb super(3+), Eu super(2+)-SrAl sub(x)O sub(y) sample was possessed the minimum dielectric permittivity () ~1.36 and dielectric loss (tan delta ) ~0.0002 at the radiowave frequency region (100 MHz).