Synthesis and luminescent property of Sm3+ doped and (Sm3+, Zr4+) co-doped calcium stannate phosphors via co-precipitation and sintering

Sm3+ doped calcium stannate (CaSnO3:Sm3+) and (Sm3+, Zr4+)-co-doped calcium stannate (CaSnO3:Sm3+, Zr4+) photoluminescent phosphors were synthesized via co-precipitation and subsequent sintering in oxidizing atmosphere at 1400 degrees C for 60 min with SnCl4.5H2O, CaCl2.2H2O, ZrO(NO3)(2.x)H2O and Sm2O3 as main raw materials. The synthesized samples were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, photoluminescent spectroscopy, luminescent decay curves, afterglow spectroscopy and thermo-luminescent glow curves. The results show that CaSnO3 pure phase is synthesized in co-precipitation reaction at an optimum molar ratio of CaCl2.2H2O:SnCl4.5H2O of 1.4:1.0 and subsequent sintering at 1400 degrees C for 60 min. Calcium stannate as a host matrix can be doped with Sm3+ ions or co-doped with Sm3+/Zr4+ ions for the formation of white photoluminescent phosphors. CaSnO3:0.03Sm(3+) phosphor has an optimum photo luminescent intensity. Also, the fluorescent emission intensity of CaSnO3:0.03Sm(3+),0.04Zr(4+) phosphor under excitation of 365 nm wavelength can be enhanced due to Zr4+ ions doping at an optimum doping amount y of 0.04. The CIE 1931 chromaticity coordinates change from (0.3600, 0.3535) for CaSnO3:0.03Sm(3+) phosphor to (0.3622, 0.3574) for CaSnO3:0.03Sm(3+), 0.04Zr(4+) phosphor as the average crystalline size decreases from 71.5 to 68.3 nm and the unit cell volume increases from 0.2686 to 0.2775 nm(3). In addition, the electron transition mechanism for the photoluminescent and long afterglow properties was also discussed.