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Detailed Program
Paper Number : GL-O08
Time Frame : 14:19~14:31
Presentation Date : Thurse day, 27, November
Session Name : Glass & Optp-Electonic Materials
Session Chair 1# : Woon Jin Chung
Session Chair 2# : Hirokazu Masai
Influence of composition on near-infrared luminescence of BaSnxO3
Yosuke OHYA
Nagaoka University of Technology
Near-infrared (NIR) phosphors have attracted attention in various fields such as in vivo luminescence imaging1) and spectral conversion materials for Si solar cells2). The GaAs and YAG:Er is known as phosphors exhibiting a strong infrared luminescence. They include a rare earth element or toxic element which leads the problems on raw material supply and handling of the synthesis and disposal. Barium stannate (BaSnO3) has cubic perovskite crystal structure without rare earth nor toxic elements. Mizoguchi et al.3) reported that strong near-infrared luminescence was observed in BaSnO3. They presumed that the origin of the luminescence related to Sn2+. In this study, the influence of molar ratio of Sn to Ba in BaSnxO3 on near-infrared luminescence was investigated to increase the luminescent intensity.
The powders of BaSnxO3 (x = 0.80 – 1.60) were synthesized by solid-state reaction. Powders of SnO2 and BaCO3 as starting materials were mixed in the molar ratio of Ba : Sn = 1 : x (x = 0.80 – 1.60) in 2 - propanol using an alumina mortar and pestle. The mixture was pressed into pellets under a uniaxial pressure of 70 MPa and sintered at 1350¡É for 3 h in air.
XRD measurements revealed that all the resultant samples had BaSnO3 phase. From the cathodoluminescence measurements, all the samples exhibited near-infrared luminescence with a peak wavelength at 890 nm. Fig.1 shows the dependence of luminescence intensity on starting composition x. The intensity increased with increasing x, and reached the maximum at x = 1.25. Further increasing x resulted in the decrease of the intensity which reflects a concentration quenching. The luminescence intensity of x = 1.25 was 2 times higher than that of x = 1.00. The results imply that the excess Sn plays an important role in the enhancement of the luminescence. Result of XPS measurements will be reported in order to discuss the enhancement.

Fig.1. The dependence of near-infrared luminescence intensity
on starting composition x of BaSnxO3.

References:
[1]Michael D. Ward et al., Coordin. Chem. Rev., 251(2007)1663
[2]Ye Li et al., Appl. Phys. Exp., 6(2013) 082301
[3]H. Mizoguchi et al., J. AM. CHEM. SOC., 126(2004) 9796
Acknowledgements :