Luminescence and Energy Transfer Characteristics of Tb3+- and Ce3+-Codoped BaBPO5 Phosphors

The luminescence properties of barium borate phosphate phosphors doped with trivalent terbium ions and the effects of codoping cerium and sodium ions on their emission characteristics were investigated. BaBPO 5 :Tb 3+ phosphors exhibit intense green emissions upon excitation at 230 nm. The emissions can be assigned to various 5 D 4 → 7 F J ( J =3, 4, 5, and 6) transitions of Tb 3+ ions. Excitation in the 200–230 nm range in BaBPO 5 :Tb 3+ is ascribed to spin-allowed transitions. The relatively weak excitation band at 268 nm is attributed to spin-forbidden transitions. The codoping of Ce 3+ ions along with Tb 3+ in BaBPO 5 results in Tb 3+ emissions and the quenching of Ce 3+ emissions. Energy transfer from Ce 3+ ions to Tb 3+ ions increases with an increase in Ce 3+ content. The codoping of sodium ions in terbium and cerium ions-doped BaBPO 5 phosphors leads to luminescence enhancement. This enhancement is attributed to the reduction in non-radiative losses. These investigations reveal that the phosphors containing Tb 3+ , Ce 3+ , and Na + ions in the BaBPO 5 host have potential for applications as green phosphors for tricolor lamps.