Luminescence, energy transfer and thermal stability of LiBaB9O15:Sm3+, Eu3+ for white LEDs

Abstract A series of Sm 3+ , Eu 3+ , and Sm 3+ /Eu 3+ doped LiBaB 9 O 15 are synthesized by a high temperature solid-state method. LiBaB 9 O 15 :Eu 3+ can produce red emission ( λ ex = 395 nm), and the peak locates at 616 nm, which is attributed to 5 D 0 → 7 F 2 transition of Eu 3+ . LiBaB 9 O 15 :Sm 3+ can create orange–red emission ( λ ex = 395 nm), and the peak locates at 599 nm, which is assigned to 4 G 5/2 → 6 H 7/2 transition of Sm 3+ . The energy transfer from Sm 3+ to Eu 3+ in LiBaB 9 O 15 is confirmed by decay times of Sm 3+ . When the temperature is 150 °C, the emission intensity of Eu 3+ in LiBaB 9 O 15 :0.05Sm 3+ , 0.1Eu 3+ is decreased to 76% of the initial intensity at room temperature, and the activation energy is calculated to be 0.268 eV, which prove good thermal stability of LiBaB 9 O 15 :Sm 3+ , Eu 3+ . The emission intensity of LiBaB 9 O 15 :Sm 3+ , Eu 3+ can be tuned by tuning Eu 3+ content, and Commission International de I’Eclairage (CIE) chromaticity coordinates of LiBaB 9 O 15 :Sm 3+ , Eu 3+ are located in the red region.