Tunable single-host full-color-emitting Ca9Zn1.5(PO4)7: Eu, Tb phosphor via Eu2+/Eu3+ dual-emitting

A series of Ca9Zn1.5(PO4)7: Eu, Tb phosphors were prepared by solid-state reaction method under reductive atmosphere. The crystal structure and morphology of the phosphors were characterized by the X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The results showed that the phosphors were pure and the doped ions did not change the structure of phosphors. Photoluminescence results indicated that Ca9Zn1.5(PO4)7: Eu shows a sharp blue emission peaking at 420 nm that was produced by 4f-5d transition of Eu2+, and accompanied by the emission of Eu3+ under UV excitation. The phosphor of Ca9Zn1.5(PO4)7: Tb shows that peaks within 370-380 nm correspond to the 7F6→5D3, 5G6, and 5L10 transitions. Additionally, the corresponding CIE color coordinate of Ca9Zn1.5(PO4)7: Eu, Tb changes from (0.2548, 0.087) to (0.3365, 0.3117) due to the energy transfer of Eu2+→Tb3+→Eu3+, which covering the purple to white region. Based on these summary, Ca9Zn1.5(PO4)7: Eu, Tb is a potential single-host white light emitting phosphor applied in WLEDs.