Synthesis of SnO_2 Nanoparticles by Facile Aqueous and Non-Aqueous Solution Processes: Structural and Optical Properties

摘要

The size-controlled and well-dispersed SnO_2 nanoparticles were synthesized via aqueous and non-aqueous sol-gel method using dihydrated tin dichloride (SnCI_2-2H_2O) as a precursor and ammonium chloride (NH_4CI) as a weak ionic media. Resultant precipitate was calcined at 450 ℃ in dry air and the calcined white powder was characterized for detailed chemical, structural and morphological properties. Scanning and tunneling electron microscopic observation showed agglomerated particles with particle size varying from 9-15 nm. X-ray diffraction results revealed diffraction pattern matching to tetragonal phase of SnO_2 with broader peak showing nanometric nature of particles. The presence of symmetric and asymmetric frequencies at 1158 cm~(-1) and 657 cm~(-1) corresponds to Sn-0 bond, which gets stronger on annealing, supporting formation of a strong Sn-O-Sn network, as observed from Fourier transform (FTIR) spectroscopy. Raman spectroscopic observation revealed broad band at 568 cm~(-1) corresponding to surface modes and intense bands at 623 cm~(-1) corresponding to the different modes of vibrations of Sn-0 bonds in tetragonal SnO_2. Raman scattering result showed a broad band at 568 cm~(-1) corresponding to surface modes and the intense bands at 623 cm~(-1) corresponding to the different modes of vibrations with expansion and contraction of Sn-0 bonds in tetragonal SnO_2.