Multicolor-tunable Ca_8MgBi(PO_4)_7: Ce~(3+),Tb~(3+), Mn~(2+) phosphors under dual-channel excitation

摘要

A series of color-tunable phosphors Ca_8MgBi(PO_4)_7(CMBPO): Ce~(3+), Tb~(3+), Mn~(2+) have been prepared by high-temperature solid-state reaction process. The X-ray diffraction (XRD), field-emission scanning electron microscope (FESEM), photolu-minescence excitation (PLE) and emission (PL) spectra were utilized to characterize the samples. Through the dual-channel excitation process, energy transfers (ET) occur simultaneously between Ce~(3+) →Tb~(3+) and Ce~(3+) →Mn~(2+). In addition, ETs process from Ce~(3+) to Tb~(3+)/Mn~(2+) has been proved to be a resonance type, which is manifested by dipole-dipole/dipole-quadrupole interactions. Moreover, the emission band of CMBPO:0.20Mn~(2+) distributed in the red and far-red regions matches well with the red light wavelength required for phytochrome protein (P_R and P_(FR)), 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:0.10Ce~(3+), 0.08Tb~(3+), zMn~(2+) can emit white light by properly tuning the ratio of Tb~(3+) and Mn~(2+) under ultraviolet (UV) excitation. The results suggested that the present phosphors can be a potential candidate for white light emitting diodes (WLEDs).