Investigation of structural, optical, electrochemical and dielectric properties of SnO₂/GO nanocomposite

We report the synthesis of tin dioxide/graphene oxide (SnO₂/GO) nanocomposite through simple hydrothermal method. X-ray diffraction (XRD) and transmission electron microscopy (TEM) confirm the rutile tetragonal structure of the nanocomposite with average particle size of 13.37 ± 3.57 nm. The presence of only Sn, O and C in the EDX spectrum confirms the purity of our sample and a large defect density in the composite is found. The 3.7 eV band gap energy, determined by ultra-violet (UV) and photoluminescence (PL), of the nanocomposite is compatible with that of SnO₂. Electrochemical measurements have shown that the material has a nice reversible redox process, suggesting its good capacitive behavior as well as a very low internal and charge transfer resistances of 1.43 Ω and 2.12 Ω, respectively. An increase in dielectric constant is observed, which is attributed to small grain size and high defect density. Conduction takes place through hopping process and the rapid increase in conductivity at high frequencies is due to increase in charge density (detached charges from traps + conduction electrons).