Insight into the synthesis and luminescence properties of the single-ion-activated single-phased Na3ScSi2O7:Dy3+ phosphor for white light-emitting diodes

Abstract

In recent years, single-ion activated single-phase white phosphors played a crucial role in the field of near-ultraviolet (n-UV) white light-emitting diode (w-LED) illumination. In this work, a series of Na3Sc1–xSi2O7:xDy3+ phosphors was successfully prepared by high-temperature solid-state reaction method. The morphology and phase composition of the phosphors were confirmed by X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM). Due to the 6H15/2 → 6P7/2 transition of Dy3+, the photoluminescence (PL) excitation spectrum of Na3Sc1–xSi2O7:xDy3+ exhibits a series of absorption peaks in the range of 250–450 nm and the strongest excitation peak is located at 349 nm. The PL spectra shows that the optimal doping concentration of Dy3+ is 0.13, which is controlled by dipole–dipole interaction according to the corresponding concentration quenching mechanism. The thermal stability of Na3Sc0.87Si2O7:0.13Dy3+ phosphor was investigated in detail and the compound has good thermal stability with activation energy of 0.198 eV. The decay time value of Na3Sc0.87Si2O7:0.13Dy3+ phosphor was calculated to be 0.4015 ms. The CIE chromaticity coordinates indicated that the phosphor produced warm white-light emission and testified the potential application of Na3ScSi2O7:Dy3+ as a new-style w-LEDs phosphor.