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

Abstract

A series of Sm3+, Eu3+, and Sm3+/Eu3+ doped LiBaB9O15 are synthesized by a high temperature solid-state method. LiBaB9O15:Eu3+ can produce red emission (λex=395nm), and the peak locates at 616nm, which is attributed to 5D0→7F2 transition of Eu3+. LiBaB9O15:Sm3+ can create orange–red emission (λex=395nm), and the peak locates at 599nm, which is assigned to 4G5/2→6H7/2 transition of Sm3+. The energy transfer from Sm3+ to Eu3+ in LiBaB9O15 is confirmed by decay times of Sm3+. When the temperature is 150°C, the emission intensity of Eu3+ in LiBaB9O15:0.05Sm3+, 0.1Eu3+ is decreased to 76% of the initial intensity at room temperature, and the activation energy is calculated to be 0.268eV, which prove good thermal stability of LiBaB9O15:Sm3+, Eu3+. The emission intensity of LiBaB9O15:Sm3+, Eu3+ can be tuned by tuning Eu3+ content, and Commission International de I’Eclairage (CIE) chromaticity coordinates of LiBaB9O15:Sm3+, Eu3+ are located in the red region.