Blue and green emissions with high color purity from nanocrystalline Ca2Gd8Si6O26:Ln (Ln = Tm or Er) phosphors

Blue and green light emissive nanocrystalline Ca2Gd8Si6O26 (CGS):Tm3+ and CGS:Er3+ phosphors with high color purity were prepared by solvothermal reaction method. The structural and morphological properties of these phosphors were evaluated by the powder X-ray diffraction (XRD) and scanning electron microscopy, respectively. From the XRD results, Tm3+:CGS and Er3+:CGS phosphors had the characteristic peaks of oxyapatite in the hexagonal lattice structure. The visible luminescence properties of phosphors were obtained by ultraviolet (UV) or near-UV light and low voltage electron beam (0.5–5 kV) excitation. The photoluminescence and cathodoluminescence properties were investigated by changing the variation of Tm3+ or Er3+ concentrations and the acceleration voltage, respectively. The CGS:Tm3+ phosphors exhibited the blue emission due to 1D2→3F4 transition, while the CGS:Er3+ phosphors showed the green emission due to 4S3/2→4I15/2 transition. The color purity and chromaticity coordinates of the fabricated phosphors are comparable to or better than those of standard phosphors for lighting or imaging devices.

Figure optionsDownload as PowerPoint slideHighlights
► Nanocrystalline Ca2Gd8Si6O26 (CGS):Tm3+ and CGS:Er3+ phosphors were prepared by solvothermal reaction method.
► The visible luminescence properties of phosphors were investigated by exciting with ultraviolet (UV) or near-UV light and low voltage electron beam (0.5–5 kV).
► The photoluminescence spectra of CGS:Tm3+ under 359 nm excitation and CGS:Er3+ under 380 nm excitation showed the strong blue (1D2 → 3F4 at 456 nm) and green (4S3/2 → 4I15/2 at 550 nm) colors with the color purity 87% and 96%, respectively
► The low accelerating voltage cathodoluminescence spectra of CGS:Tm3+ and CGS:Er3+ showed the strong blue and green emissions with the high color purity 95% and 96%, respectively.
► The obtained results are hint at the promising applications to produce high quality LEDs and FED devices.