Luminescent properties of Tb3+-doped Ca2SnO4 phosphor

The novel green light emitting phosphors Ca2SnO4:Tb3+ were synthesized via a traditional solid state reaction method. All as-prepared phosphors were studied systematically by X-ray diffraction, scanning micrograph images, photoluminescence spectra, decay curves, afterglow spectra and thermoluminescence glow curves. The cross-relaxation of two adjacent Tb3+ ions led to the main emission peaks locate at 483 and 545 nm under excitation of 255 nm. The CIE chromaticity coordinates are x=0.197 and y=0.279. The intensities of photoluminescence and afterglow are dependent on the concentration of Tb3+ ions. The optimal concentration of Tb3+ ions for the best afterglow characteristic was experimentally to be 0.1 mol%. After irradiation by 254 nm, the duration of afterglow can last more than 3 h. The mechanism of long afterglow in Ca2SnO4:Tb3+ is also discussed.