Synthesis and characterization of thermostable Dy3+-doped La5NbMo2O16 yellow-emitting phosphors for w-LEDs

In order to develop new phosphors, a series of novel trivalent dysprosium (Dy3+) activated single-phase yellow-emitting La5NbMo2O16 phosphors were firstly prepared through the high-temperature solid-state reaction method. Powder X-ray diffraction (XRD) patterns were measured to check the crystalline structure of La5NbMo2O16 phosphors. The photoluminescence (PL) spectra were used to characterize the luminescence properties of the prepared La5NbMo2O16:Dy3+ phosphors. Under 386 nm excitation, the PL spectra of La5NbMo2O16:Dy3+ phosphors mainly contain three dominant sharp peaks at blue (486 nm), yellow (574 nm), and red emission (669 nm), respectively. The intense peak at 574 nm attributes to the typical 4F9/2-6H13/2 transition of Dy3+ ions. The optimal sample is La5NbMo2O16:10 mol%Dy3+ phosphor with the estimated Rc = 18.89 Å. The obtained La5NbMo2O1610 mol%Dy3+ product shows high thermostability with high quenching temperature (above 480 K) and good activation energy (Ea = 0.32 eV). Besides, the CIE chromaticity coordinate (0.442, 0.474) of the La5NbMo2O16:10 mol%Dy3+ phosphor is in the yellow region. A white light-emitting diode (w-LED) with the chromaticity coordinates of (0.322, 0.335), a correlated color temperature (CCT) of 5974 K, and a color rendering index (Ra) of 90 was successfully fabricated. All results indicate that La5NbMo2O16:Dy3+ phosphors have extensive application prospects for w-LEDs.