Crystal Structure and Photoluminescence Properties of Ca3(PO4)2:Eu3+ Phosphors With High Emission Efficiency

ABSTRACT The influence of Eu 3+ concentration on the crystal structure and photoluminescence (PL) properties of Ca 3‐ x (PO 4 ) 2 : x Eu 3+ (0.06 ≤ x ≤ 0.10) phosphors is systematically investigated using X‐ray diffraction (XRD) Rietveld refinement, scanning electron microscopy (SEM), Fourier transform infrared (FT‐IR) spectroscopy, UV‐visible spectroscopy, and PL spectroscopy. The prepared phosphors exhibit a single rhombohedral phase with the space group R 3 c . The constituent ions occupy various crystallographic sites, including Ca(1–5), Eu(1–3), P(1–3), and O(1–10) sites. Under 397‐nm excitation, the emission spectra show distinct emission peaks between 525 and 725 nm, corresponding to the 5 D 1 → 7 F j ( j = 1 and 2) and 5 D 0 → 7 F j ( j = 1, 2, 3, and 4) transitions of Eu 3+ ions. The concentration quenching observed in the phosphors is attributed to electric multipolar interactions. Among the prepared phosphors, Ca 2.92 (PO 4 ) 2 :0.08Eu 3+ phosphor shows the highest emission efficiency and excellent color performance. These results demonstrate that Ca 3‐ x (PO 4 ) 2 : x Eu 3+ phosphors have significant potential as red‐emitting materials for white light–emitting diode (WLED) applications.