Luminescent properties of Sr2B2O5: Tm3+, Na+ blue phosphor

A novel blue phosphor, Sr2B2O5: Tm3+, Na+ for white light-emitting diodes (W-LEDs) was prepared by solid-state synthesis and its structure and luminescence properties were investigated. This phosphor can be effectively excited within the broad near ultraviolet (NUV) wavelength region, from 340 nm to 370 nm, and exhibits a satisfactory blue performance. The emission peaks are observed at 457 nm (blue) and 475 nm (blue), due to the respective transitions of 1D2→3F4 and 1G4→H6. Seven mole percent of doping concentration of Tm3+ was shown to be optimal. Concentration quenching occurs when Tm3+ concentration is beyond 7 mol%, its mechanism being explained by dipole–dipole interaction of Tm3+ and being confirmed by decay property measurements. We have made a deep analysis on the effect of charge compensation reagent on luminescence intensity. Good blue emissions with the CIE chromaticity coordinates (0.173, 0.165) could be achieved. Our results suggest that the Sr2B2O5: Tm3+, Na+ phosphor is a potential blue-emitting material.