A High Absorption Efficiency Blue-Emitting Phosphor NaSrScSi2O7:Eu2+ for Near-Uv-pumped White Light-Emitting Diodes

The Eu2(+ )ion is extensively used as an activator due to its wide excitation band and high efficiency emission spectrum. However, most Eu2+-activated blue-emitting phosphors have low absorption efficiency in the near-ultraviolet (n-UV) region or lack the short-wavelength blue light emission (<450 nm), resulting in UV light leakage or poor color rendering. Herein, we have successfully prepared a brand-new blue phosphor NaSrScSi2O7: Eu2+ by solid-state reaction method. The Rietveld refinement of the powder diffraction data, luminescent properties, decay lifetime, quantum efficiency-and thermal quenching have been investigated in detail. Under 345 nm excitation, the NaSrScSi2O7: 0.03Eu(2+) phosphor manifests an asymmetric emission spectrum centered at 427 nm, and notably, shows a high absorption efficiency of 84.35%. Finally, we encapsulated two white light-emitting diodes (WLEDs) devices using as-prepared blue-emitting phosphor and three commercial phosphors. At 80 mA drive current, both packaged devices demonstrate warm white light. Meanwhile, the WLED-2 with NaSrScSi2O7: 0.03Eu(2+) blue-emitting phosphor has a lower correlated color temperature of 3726 K, its spectrum complements more short-wavelength spectrum, and the special color rendering index R-6 and R-7 increased from 95.2, 94.5 to 98.3, 96.5, respectively, compared with WLED-1 without present phosphor. These results demonstrate that NaSrScSi2O7: Eu2+ blue-emitting phosphor is a prospective novel luminescent material for WLEDs. (C) 2022 Elsevier B.V. All rights reserved.