Luminescence characteristics of strontium borate phosphate phosphors

New green emitting phosphors based on SrBPO5 with high brightness are prepared via solid-state reactions at high temperatures in reducing atmosphere. SrBPO5 doped with trivalent terbium ions emit weakly in blue and orange light region and strongly in green light region on excitation at 220 nm. The blue and green-orange emissions are ascribed to 5D3 → 7FJ and 5D4 → 7FJ (where J = 3-6) transitions of Tb3+ ions, respectively. The co-doping of Ce3+ and Tb3+ in SrBPO5 phosphors results in strong emission from Tb3+ ions on excitation in the UV region corresponding to excitation bands of Ce3+ ions. The enhanced luminescence observed in Sr0.94Tb0.01Na0.05BPO5 and Sr0.89Tb0.01Ce0.05Na0.05BPO5 phosphors is understood as due to a reduction in the non-radiative energy transfer. Sr0.89Tb0.01Ce0.05Na0.05BPO5 synthesized in reducing atmosphere show nearly two-order enhancement in emission intensity of 542 nm peak on excitation at 254 nm as compared with the intensity of 542 nm emission in Sr0.99Tb0.01BPO5. These results suggest the possibility of the potential of SrBPO5-related phosphors in tri-color lamps.