Excellent thermostability and emission properties of Sr2CaTeO6:Sm3+ red emitting phosphor for high color-rendering white LEDs

A novel phosphor, red emitting Sr2CaTeO6:Sm3+ has been developed for white LEDs. The crystal structure and luminescence properties of this phosphor were investigated systematically. The space group of phase Sr2CaTeO6 compounds with a double-perovskite structure was found to be monoclinic P21/n (No.14). The Sr2CaTeO6:Sm3+ showed broad excitation band from 350 to 500 nm (monitored with emission wavelength at 648 nm), which is well aligned with 365 and 400 nm LED chips. Upon 407 nm near-UV excitation, the Sr2CaTeO6:Sm3+ exhibited red emission peak at about 658 nm. We found that Sr2CaTeO6:Sm3+ with 2 mol% of Sm3+ doping achieved the optimal performance. Meanwhile, the Sr2CaTeO6:Sm3+ phosphor showed good thermal stability. Finally, a near-UV pumped warm w-LED with the Sr2CaTeO6:Sm3+ phosphor, blue-emitting BAM:Eu2+ and green-emitting Lu-AG:Ce3+ phosphors was fabricated, which indicated that the Sr2CaTeO6:Sm3+ can be a promising red-emitting material for pc-LEDs.