A white-light emitting phosphor LuNbO4:Dy3+ with tunable emission color manipulated by energy transfer from NbO43− groups to Dy3+

A single-phase white-light emitting phosphor LuNbO4:Dy3+ was synthesized using the solid state method in air for the first time. X-ray diffraction (XRD) along with excitation spectra, emission spectra, decay times and thermal stability were exploited to characterize the asprepared phosphors. Under ultraviolet (UV) excitation (261 nm), the self-activated emission of the LuNbO4 host is peaked at 402 nm with a broad emission band ranging from 320 nm to 600 nm, ascribing to the charge transfer in NbO43− groups, which has spectral overlapping to the excitation of f-f transitions of Dy3+ in LuNbO4:Dy3+ phosphors. They show both the broad host emission and sharp emission lines due to the characteristic f-f transitions of Dy3+ ions, which exhibit tunable white light emissions due to the energy transfer from the NbO43− groups in the host to Dy3+ with increased Dy3+ content. The optimal chromaticity coordinates and Correlated Color Temperature (CCT) in LuNbO4:Dy3+ are (x=0.336, y=0.311) and 5299 K, respectively, which occur when the doping Dy3+ is 0.01. The decrease of decay lifetime for host emission in LuNbO4:Dy3+ with raised Dy3+ content demonstrates the energy transfer from the host to Dy3+. The energy transfer mechanism in LuNbO4:Dy3+ phosphors was determined to be a resonant type via dipole-dipole mechanism. Moreover, good thermal stability was also identified in Lu0.99NbO4:0.01Dy3+ and its emission intensity was reduce to 85% of its initial value at 100 °C and 62% at 200 °C, the chromaticity color coordinate values of Lu0.99NbO4:0.01Dy3+ had a slight shift with raised temperature. The current research suggests that LuNbO4:Dy3+ could potentially serve as a single-phase white-light emitting phosphor in solid-state lighting and display fields.