Luminescence and structural characterization on praseodymium (Pr3+) doped potassium bromide (KBr) single crystals

The luminescence properties of praseodymium (Pr3+) ion in potassium bromide (KBr) host have been investigated. The excitation bands observed in the region 220-300nm are attributed to the transitions from 4f level to the 5d crystal field splitting levels of Pr3+ ion. Emission bands originated due to transition of P-3(2) H-3(6) (564nm), P-3(0) H-3(6) (604nm), D-1(2) P-3(4) (721nm) and P-3(0) F-3(2) (659nm) have been observed. Optical absorption, photoluminescence (PL) and thermoluminescence (TL) studies confirms the trivalent state of Pr3+ ion in KBr host. Trap parameters for the TL glow curve have been calculated and the values are tabulated by using Chen's peak shape method. The lattice cell parameters of Pr3+ doped KBr single crystals are a=b=c=6.596 angstrom, ===90 degrees. From the scanning electron microscopy (SEM) micrograph analysis, the particle size ranges from a few micrometres to 5m. Electron paramagnetic resonance (EPR) spectrum exhibits two resonance signals at magnetic fields of 2895 and 3106 gauss with g-values of 2.32 and 2.16, respectively, calculated using Lande's formula.