Raman spectra, photoluminescence, and low-frequency dielectric properties of Ba_(0.97)La_(0.02)Ti_(1-x)Nb_(4x/5)O_3 (x=0.00,0.05) ceramics at room temperature

摘要

We are interested to investigate the effect of Nb~(5+) addition on morphological, dielectric, and optical properties of Ba_(0.97)La_(0.02)Ti_(1-x)Nb_(4x/5)O_3 (for x = 0.00, 0.05) ceramics. The BLT and BLT_(0.95)N_(0.04) were successfully synthesized by a low-cost molten-salt method. In addition, the structural phase purity of ceramics was definite by using X-ray diffraction (XRD) at room temperature (RT). Afterward, the morphology of our examples was explored using transmission electron microscopy (TEM) as well as dielectric characterizations. The dielectric constant decreased with increasing frequency. This is assigned to Maxwell-Wagner (M-W) interfacial polarization. What's more, the room temperature photoluminescence (PL) spectra indicated a synergic effect on BLT_(1-x)Nb_(4x/5) ceramics. At RT, compared to BLT sample, the peaks in the visible region for doped compound are shifted to the highest wavelengths. Note also that width at mid-height reduce for Nb~(5+)-doped BLT than none-doped example. Based on the photometric characterization and the results of the CIE coordinates, they discovered that synthesized perovskite may represent an appropriate candidate for semiconductor lighting devices and optoelectronic applications. Importantly, the tetragonal phases of BLT and BLT_(0.95)Nb_(0.04) examples can be improved by XRD and Raman spectrum. The incorporation of ions La~(3+) in the Ba-site is remarkable by the peak observed about 805 cm~(-1). As well, all modes show a significant broadening with the incorporation of Nb~(5+) on the titanium-site.