Multicolor-tunable Ca8MgBi(PO4)7: Ce3+, Tb3+, Mn2+ phosphors under dual-channel excitation

A series of color-tunable phosphors Ca8MgBi(PO4)7(CMBPO): Ce3+, Tb3+, Mn2+ have been prepared by high-temperature solid-state reaction process. The X-ray diffraction (XRD), field-emission scanning electron microscope (FESEM), photoluminescence excitation (PLE) and emission (PL) spectra were utilized to characterize the samples. Through the dual-channel excitation process, energy transfers (ET) occur simultaneously between Ce3+  → Tb3+ and Ce3+  → Mn2+. In addition, ETs process from Ce3+ to Tb3+/Mn2+ has been proved to be a resonance type, which is manifested by dipole–dipole/dipole-quadrupole interactions. Moreover, the emission band of CMBPO:0.20Mn2+ distributed in the red and far-red regions matches well with the red light wavelength required for phytochrome protein (PR and PFR), indicating that the phosphor can be used as a new type of red luminescent powder absorbed by plant photosensitive pigment and promoted plant growth. Importantly, the CMBPO:0.10Ce3+, 0.08Tb3+, zMn2+ can emit white light by properly tuning the ratio of Tb3+ and Mn2+ under ultraviolet (UV) excitation. The results suggested that the present phosphors can be a potential candidate for white light emitting diodes (WLEDs).