Sm3+/Pr3+ biactivated Ca3Y2Ge3O12:0.04Sm3+:Pr3+ red phosphor with high thermal stability for low correlated temperature WLED

ABSTRACT Sm3+ and Pr3+ ion co-doped phosphors Ca3Y2Ge3O12:0.04Sm3+:yPr3+ (0.001≤y≤0.006 mol%) were synthesized by high tempereture calcination process. The XRD results showed that samples Ca3Y2Ge3O12:0.04Sm3+:yPr3+ (0.001≤y≤0.006) were matched well with the standard profile Ca3Y2Ge3O12 (PCSD No. 27-0092) which possessed a cubic structure with the space group Ia-3d (230), and these synthesized samples exhibited irregular particles with large size of about 40 μm. The photoluminescence (PL) study demonstrated that the co-doped Pr3+ ions could improve the PL properties through the energy transition (ET) process between Pr3+ ions and Sm3+ ions, leading to a smaller liftimes of Ca3Y2Ge3O12:0.04Sm3+:0.003Pr3+ than Ca3Y2Ge3O12:0.04Sm3+. The optimum Pr3+ ions doping concentration was y = 0.003 and the CIE coordinates (0.5249, 0.4730) of Ca3Y2Ge3O12:0.04Sm3+:0.003Pr3+ lied in red light region. Notably, sample Ca3Y2Ge3O12:0.04Sm3+:0.003Pr3+ exhibited better thermal stability and larger activation energy (Ea) by compariton of Ca3Y2Ge3O12:0.04Sm3+. Finally, the WLED device based on Ca3Y2Ge3O12:0.04Sm3+:0.003Pr3+, (Ba, Sr)2SiO4: Eu2+ and a blue chip of 395 nm exhibited a low correlated temperature (CCT) of 3929 K and a color rendering index (Ra) of 89.