Luminescence properties of BiPO4:Ln (Ln = Dy3+, Tb3+ and Sm3+) orthophosphate phosphors for near-UV-based solid-state lighting

The BiPO 4 :Ln (Ln = Dy 3+ , Tb 3+ and Sm 3+ ) phosphor were prepared using wet chemical synthesis and studied its photoluminescence properties. Under 352 nm excitation, the BiPO 4 :Dy 3+ phosphor shows the blue (481 nm) and yellow (575 nm) emissions due to the 4 F 9/2 → 6 H 15/2 and 4 F 9/2 → 6 H 13/2 transitions of the Dy 3+ ion, respectively. When BiPO 4 :Tb 3+ phosphor was excited at 378 nm, it emits efficient narrow green emission at 545 nm due to 5 D 4 → 7 F 5 transition. The BiPO 4 :Sm 3+ phosphor shows yellow, orange and red emissions centred at 598 nm, which is attributed to the 4 G 5/2 → 6 H 7/2 transition of the Sm 3+ ion. The CIE coordinates indicate that the prepared phosphors have high colour purity. The photoluminescence results suggests that BiPO 4 :Ln (Ln = Dy 3+ , Tb 3+ and Sm 3+ ) phosphor may be used as a possible material for near-UV-based solid-state lighting.