Nanocrystalline Ca2Gd8Si6O26 (CGS): Sm3+ 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 Sm3+ concentration. Under 405 similar to nm excitation wavelength, the photoluminescence spectra showed three emission peaks at 565 similar to nm (4G5/2 similar to?similar to 6H5/2) and at 650 similar to nm (4G5/2 similar to?similar to 6H9/2), and with an intense orange emission at 600 similar to nm (4G5/2 similar to?similar to 6H7/2). Based on the orange emission performance, the Sm3+ concentration was optimized to be at 2 similar to mol%. The low voltage cathodoluminescence (CL) properties were also performed for 2 similar to mol% Sm3+-doped CGS phosphors as a function of accelerating voltage (15 similar to 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.