Effect of copper on structural, optical and electrochemical properties of SnO2 nanoparticles

Pure and Cu doped Sn0 2 nanopowders have been synthesized by chemical precipitation method using SnCl 4 .5H 2 O, NH 3 .H 2 O and CuSO 4 .5H 2 O as raw materials. The products have been annealed at 600 ° C for 5 hours under ambient condition in order to improve the crystallinity. Powder XRD results show that the samples crystallize in tetragonal rutile type Sn0 2 phase. The average crystalline size of pure Sn0 2 is found to be around 10 nm. The crystal structure of the Sn0 2 does not change with the introduction of Cu, but the crystalline size decreases to 8 nm and 6.5 nm for Cu doping of 10 & 20 wt.% respectively. These results have been confirmed by the transmission electron microscopy (TEM) studies. UV-VIS diffusion reflectance spectroscopy (DRS) revealed the band gap energies to be 3.56, 3.31, 3.28 eV for pure and Cu (10 & 20 wt.% ) doped Sn0 2 respectively. Temperature dependent resistivity measurement showed that both the pure and Cu doped samples are suitable for gas sensing applications. The electrochemical nature of the samples has been studied using cyclic voltammetric method.