Photoluminescence in Pb2+ activated SrB4O7 and SrB2O4 phosphors

The powder samples of SrB4O7:Pb2+ and SrB2O4:Pb2+ were prepared by solution combustion synthesis method. The synthesis is based on the exothermic reaction between the fuel (Urea) and Oxidizer (Ammonium nitrate). The synthesized materials were characterized using TG-DTA, powder XRD, SEM and the photoluminescence properties were studied using a Hitachi F-7000 spectrophotometer at room temperature. Both the samples SrB4O7:Pb2+ and SrB2O4:Pb2+ show broad emission of Pb2+ respectively at 307 nm and 360 nm (corresponds to 3P1 to 1S0 transition). The optimum concentrations of Pb2+ in both the phosphors SrB4O7:Pb2+ and SrB2O4:Pb2+ were found to be 3 mol% (relative to Sr) and for this concentration the critical transfer distance R0 were calculated to be 10.21 Å and 12.22 Å respectively. The Stokes shifts were calculated to be respectively 4464 cm−1 and 8454 cm−1. The emission bands of both the phosphors are in the UV region and the phosphors can be potential candidates for application in UV lamps.