Photoluminescence and cathodoluminescence properties of nanocrystalline Ca ₂Gd ₈Si ₆O ₂₆: Sm ³⁺ phosphors

Nanocrystalline Ca ₂Gd ₈Si ₆O ₂₆ (CGS): Sm ³⁺ phosphors were synthesized by solvothermal reaction method. The structural and morphological properties of the samples were evaluated by X-ray diffraction and scanning electron microscopy. The photoluminescence excitation and emission spectra along with decay properties were investigated as a function of Sm ³⁺ concentration. Under 405 nm excitation wavelength, the photoluminescence spectra showed three emission peaks at 565 nm ( ⁴G _5/2 → ⁶H _5/2) and at 650 nm ( ⁴G _5/2 → ⁶H _9/2), and with an intense orange emission at 600 nm ( ⁴G _5/2 → ⁶H _7/2). Based on the orange emission performance, the Sm ³⁺ concentration was optimized to be at 2 mol%. The low voltage cathodoluminescence (CL) properties were also performed for 2 mol% Sm ³⁺-doped CGS phosphors as a function of accelerating voltage (1-5 kV). From the CL spectra, the reddish-orange emission was observed. The calculated Commission International De I-Eclairage chromaticity coordinates are in close proximity to the chromaticity coordinates of Nichia corporation developed amber light emitting diodes.