A potential single-component white-light-emitting phosphor CaMoO₄:La³⁺,Dy³⁺: hydrothermal synthesis, luminescence properties and energy transfer

A series of Ca_0.8La_0.2−xMoO₄:xDy³⁺ phosphors have been prepared by a hydrothermal method. The X-ray diffraction (XRD) analysis reveals that the crystal structures of the samples are coincided with the tetragonal CaMoO₄. The introduction of La³⁺ and Dy³⁺ ions does not change the structure of the host lattice. The luminescence properties indicate that Ca_0.8La_0.2−xMoO₄:xDy³⁺ exhibits a strong excitation band between 200 and 325 nm centered at 284 nm, and several sharp lines locate from 325 to 460 nm monitored by the yellow emission of 575 nm, which is matched well with the dominant emission of a UV light-emitting-diode (LED) chip. Compared with CaMoO₄:0.05Dy³⁺ phosphors, the characteristic emission intensities of 575 nm (⁴F_9/2→⁶H_13/2) and 488 nm (⁴F_9/2→⁶H_15/2) of Dy³⁺ in CaMoO₄:0.15La³⁺,0.05Dy³⁺ enhance obviously. When the doping concentration of Dy³⁺ is beyond 3%, a quenching phenomenon occurs accompanied with an energy-transfer via a dipole–dipole interaction. The energy-transfer critical distance was also calculated. The obtained CaMoO₄:0.19La³⁺,0.01Dy³⁺ shows bright white emission with the Commission Internationale de L’Eclairage (CIE) color coordinates of (0.3123, 0.3434) and a color temperature of 6429 K upon nUV-light excitation of 353 nm, indicating that the obtained phosphor may be used as a single-component phosphor for W-LEDs.