No abstract

In this paper, we have reported the photoluminescence (PL) properties of the Ba 2 Mg(PO 4 ) 2 :Eu 3+ phosphor synthesized using a wet chemical method. The preliminary scanning electron microscopy (SEM) investigation of the sample revealed irregular surface morphology with particle sizes in the 10-50 μm range. The strongest

Cerium-doped Sr4 Al14 O25 phosphor is prepared using a single-step combustion synthesis and its X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence (PL) and thermoluminescence (TL) properties are characterized. XRD reveals the formation of the desired phase in the prepared sample. SEM micrographs of the prepared Sr4 Al14 O25 phosphor show that the particle size is 10 µm. The prepared Sr4 Al14 O25 , along with Sr4 Al14 O25 :Cex (x = 0.5-5 mol%) shows a PL emission peak at 314 nm under UV excitation of 262 nm wavelength due to 5d → 4f transition. The phosphor is suitable for higher concentrations of Ce ions. The TL glow peak reveals three clearly visible distinct peaks at temperatures around 130, 231 and 336ºC. The three peaks are separated by deconvolution and kinetic parameters calculated using Chen's peak shape method. The calculation shows that the reaction follows second-order kinetics with activation energy (E) values of 0.52, 0.81 and 1.12 eV, and frequency factor (s) values of 5.58 × 10(5) , 4.53 × 10(7) and 4.57 × 10(8) s(-1) for the three individual peaks.

A new Na3Ca2(SO4)3F: Ce(3+) phosphor synthesized by a solid state diffusion method is reported. The photoluminescence study showed a single high intensity emission peak at 307 nm wavelength when excited by UV light of wavelength 278 nm. An unresolved peak of comparatively less intensity was also observed at 357 nm along with the main peak. The characteristic emission of dopant Ce in Na3Ca2(SO4)3F phosphor clearly indicated that it resides in the host lattice in trivalent form. The emission peak can be attributed to 5d → 4f transition of rare earth Ce(3+) . The prepared sample is also characterized for its thermoluminescence properties. The TL glow curve of prepared sample showed a single broad peak at 147°C. The trapping parameters are also evaluated by Chen's method. The values of trap depth (E) and frequency factor (s) were found to be 0.64 ± 0.002 eV and 1.43 × 10(7)  s(-1) respectively. The study of PL and TL along with evaluation of trapping parameters has been undertaken and discussed for the first time.

No abstract