Co-existence phenomenon of Ce3+/Ce4+ and Tb3+ in Ce/Tb co-doped Zn2(BO3)(OH)0.75F0.25 phosphor: Luminescence and energy transfer

A serials of Zn₂(BO₃)(OH)_0.75F_0.25 (ZBF), Tb³⁺, Ce^3+/4+ single-doped ZBF and Tb³⁺/Ce^3+/4+ co-doped ZBF novel phosphors with belt-like morphology were obtained through hydrothermal reaction without any surfactant. The obtained samples were characterized by XRD, SEM, EDS, TEM, TGA, XPS, DR, PL, and DT. The TGA curve shows that the phosphor is thermal stability. XPS results show that Tb³⁺ is present in the Tb-doped phosphor, and the Ce³⁺/Ce⁴⁺ mixed valence is present in the Ce-doped phosphor. The PL results indicate that ZBF host material and ZBH:Ce^3+/4+ can emit blue light, ZBF:Tb³⁺ can emit green light. Compared with the Tb³⁺ single doped phosphor, the Tb³⁺/Ce^3+/4+ co-doped phosphors shown stronger emission and shorter decay time, which is attributed to the effective energy transfer from the Ce^3+/4+ to Tb³⁺ ions.