Growth of Sm(OH)3 nanocrystals by chemical bath deposition and its thermal annealing treatment to Sm2O3

Abstract

Sm(OH)3 nanocrystals were prepared by the green chemical bath deposition (CBD) approach and further subjected to thermal annealing treatment (TAT) at 1000°C in air atmosphere to obtain Sm2O3 nanocrystals. Scanning Electron Microscopy (SEM), Fourier transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), Photoluminescence (PL) and Raman Spectroscopy techniques were employed to examine the nanocrystals. SEM micrographs showed little morphological changes after TAT. FTIR spectra displayed bands associated with Sm-OH and CO32− bonds and, after TAT, these bands disappeared completely. According to XRD results, Sm(OH)3 nanocrystals were obtained in hexagonal phase, and after TAT, the Sm2O3 cubic phase can be seen. Absorption bands associated with electronic transitions reported for Sm(OH)3 and Sm2O3 nanocrystals were registered. A shift at 4.5–4.7eV in the band gap was obtained, presenting the quantum confinement effect. The emissions band observed by photoluminescence showed peaks associated with the magnetic moment and 4G5/2→6H5/2 electronic transition. Finally, the results of Raman spectra confirmed the synthesis of Sm(OH)3 nanocrystals and their transition to Sm2O3.