Samarium-decorated ZrO2@SnO2 nanostructures, their electrical, optical and enhanced photoluminescence properties

Abstract

In the present work, pure ZrO2@SnO2 and Samarium (Sm-x) (x = 1%, 8% and 12%)-doped ZrO2@SnO2 nanoparticles (NPs) successfully synthesized by facile low-cost co-precipitation technique. As-synthesized nanostructures (NS) were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), UV-visible, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT-IR), Brunauer-Emmett-Teller (BET) spectroscopic investigation. The tetragonal crystal phase of the as-synthesized Sm-x:ZrO2@SnO2 NS confirmed by XRD analysis. The observed peak shift in the XRD patterns confirmed incorporation of dopant into host lattice. The Sm-x:ZrO2@SnO2 NS present irregular spherical morphology and high agglomeration confirmed by FESEM microscope analysis. The presence of functional groups, chemical bonding, chemical constituents and valence state of the NS confirmed by FT-IR and XPS analysis. The Sm-x:ZrO2@SnO2 NS showed higher surface area and smaller optical band gap (454 cm(2)/g and 2.12 eV) than the pure ZrO2@SnO2 NS (189-196 cm(2)/g and 2.84 eV). Photoluminescence (PL) spectra of undoped ZrO2@SnO2 and Sm-x:ZrO2@SnO2 NS exhibited oxygen vacancies. Undoped ZrO2@SnO2 NS exhibited emission intensity at 370.6 nm (lambda(excitation) = 300 nm) whereas, Sm-x:ZrO2@SnO2 NS showed emission intensities at 453.4 nm, 476.3 nm, 601.3 nm (lambda(excitation) = 300 nm). Electrical property studies of Sm-x:ZrO2:SnO2 (1%, 8% and 12%) NS showed large variation in Hall constant (0.125 x 10(6) cm(2)/coulomb to 0.647 x 10(6) cm(2)/coulomb) with proportionately large variation in the resistivity (147.8 omega-cm to 456.8 omega-cm) for all the doped samples as compared with pure ZrO2@SnO2 NS. The Sm3+-doped ZrO2@SnO2 NS showed higher stability, intense PL emission and enhanced electrical properties.