Photoluminescence, thermally stimulated luminescence and electron paramagnetic resonance investigations of Tb3+ doped SrBPO5

Trap level spectroscopic studies were carried out on γ-irradiated Tb (1 mole%) doped SrBPO5 were carried out using photoluminescence (PL), thermally stimulated luminescence (TSL) and electron paramagnetic resonance (EPR) techniques. The incorporation of Tb in the 3+ oxidation state was ascertained from PL studies. Life time for Tb3+ emission corresponding to the intense transition 5D4 → 7F5 at 543 nm was determined. The spectral characteristics of the TSL glows have shown that Tb3+ ions act as the emission center for the glow peak at 475 K. The trap parameters of the glow peak were determined. EPR investigations at room temperature/77 K revealed the stabilization of three boron oxygen hole trapped centers (BOHC's) and oxygen centered radicals such as O− and O2− and trapped electrons in room temperature γ-irradiated samples. TSL glow peak at 475 K was found to be associated with recombination of electron released from trapped electron center and the BOHC2 center.

EPR spectra of BOHC's in 2 kGy γ-irradiated SrBPO5:Tb sample using Receiver Gain RG = 4 × 104, Modulation Amplitude MA = 0.25 G, Microwave power setting 6.3 mW: (A) un-annealed sample recorded at 300 K, (B) un-annealed sample recorded at 100 K and (C) sample annealed at 550 K for 10 min and recorded at 100 K.Figure optionsDownload as PowerPoint slideHighlights
► PL studies on Tb doped SrBPO5 phosphor have shown emission due to Tb3+ associated with 5D3 → 7FJ and 5D4 → 7FJ (J = 3, 4, 5 and 6) transitions.
► The EPR studies on γ-irradiated samples revealed formation of three types of boron oxygen hole trapped centres viz., BOHC1, BOHC2 and BOHC3 and an electron trapped centre.
► The TSL peak at 475 K was associated with the thermal destruction of BOHC2.