Ca9Sc(PO4)7:Ce3+,Mn2+ - A Red-Emitting Phosphor Based on Energy Transfer

A series of novel color‐tunable phosphors, Ca9Sc(PO4)7:xCe3+,yMn2+ (CSP:xCe3+,yMn2+), have been synthesized by traditional high‐temperature solid‐state reactions. The optical properties of CSP:xCe3+ and CSP:0.02Ce3+,yMn2+ were systematically investigated with various spectral technologies. A phosphor with a broad, deep‐red emission, CSP:0.02Ce3+,0.1Mn2+, was prepared by an energy transfer process with the CIE chromaticity coordinates (0.669, 0.307). CSP:Ce3+,Mn2+ phosphors excited at 254 nm display two broad emission bands: one centered at around 360 nm is assigned to the 5d1–4f1 electronic transition of Ce3+ ions, and the other at about 650 nm is attributed to the 4T1 (4G) → 6A1 (6S) transition of Mn2+ ions. The energy transfer mechanism from Ce3+ to Mn2+ in the CSP:Ce3+,Mn2+ samples was discovered to be the dipole–dipole interaction, which was confirmed by the estimated critical distance between Ce3+ and Mn2+ (13.0 Å) by the spectral overlap method. Furthermore, the higher thermal stability of CSP:Ce3+,Mn2+ makes it feasible for a potential application in white‐light‐emitting diodes (WLEDs). A phosphor with a broad, deep‐red emission, Ca9Sc(PO4)7:0.02Ce3+,0.1Mn2+ (CSP:0.02Ce3+,0.1Mn2+), was prepared by energy transfer from Ce3+ to Mn2+ through a dipole–dipole interaction. CSP:Ce3+,Mn2+ phosphors excited at 254 nm emit light in two bands: one at around 360 nm, assigned to the 5d1–4f1 transition of Ce3+, and the other at about 650 nm, derived from the 4T1 (4G) → 6A1 (6S) transition of Mn2+.