Investigation on Structural and Optical Properties of Sodium ion (Na+) Doped Layered Perovskite Sr2CeO4

Abstract

Powder and ceramic of a few compositions of system Sr2Ce1-xNaxO4 (x=0, 0.02, 0.04, 0.06 and 0.10) were prepared by the conventional solid-state reaction method. The phase and structure of the synthesized samples were investigated by x-ray diffraction technique. The analysis of XRD data indicated that in Sr2CeO4, substitution sites of Na1+ ions depend on the doping concentration. Na1+ ions occupy Ce-sites when concentration is x = 0.02. With increasing doping amount (x=0.04, 0.06 and 0.10) Na1+ substituted into both Sr and Ce site. Purity of the synthesized samples was reconfirmed using Raman and Fourier Transformation Infrared (FTIR) spectroscopy techniques. The optical band gap was recorded by UV-Vis absorption spectra; optical band gap energy of the samples lies between 2.91 - 3.10 eV. Room temperature photoluminescence (PL) measurements show that there two excitation peaks located around 290 nm and 350 nm. For Na doped samples, intensity of higher wavelength peak is more than the lower wavelength peak making them suitable candidate for UV excitation source. All the Na1+ doped samples display an intense blue emission at 472 nm similar to undoped Sr2CeO4. But the intensity of emission for the doped samples is weak as compared to undoped sample. Scanning electron microscopic studies of fractured surfaces of the sintered pellets have indicated that dopant Na has played a significant role in the grain growth. Grain size and morphology of Na doped samples are different from undoped Sr2CeO4.