Ce3+/Mn2+-activated Ca7(PO4)2(SiO4)2: efficient luminescent materials for multifunctional applications

To develop new efficient phosphors for LEDs based on multifunctional applications, a series of Ce³⁺/Mn²⁺ activated Ca₇(PO₄)₂(SiO₄)₂ (CPS) samples were prepared by solid-state reaction method. Upon 365 nm excitation, a broad emission band around 439 nm in the Ce³⁺-single-doped CPS was observed. The optimal Ce³⁺ concentration was determined to be 3%, for which the quantum efficiency was obtained to be 90.4%, higher than that of the commercial BAM phosphor. By monitoring 458 nm, an intense and broad excitation band was found from 240 to 400 nm, which can match well with the near-ultraviolet (NUV) LED chip. For Ce³⁺-Mn²⁺ codoped CPS, a new red emission band belonging to Mn²⁺ appeared and an energy transfer from Ce³⁺ to Mn²⁺ was confirmed. It was also found that the emission spectra of Ce³⁺/Mn²⁺ could well cover the optical absorption bands of plants. The fabrication of the phosphors on NUV LED chip indicates that the present phosphors could be promising in solid lighting and plants growth.