Dangling ultrafine nano silica on graphene oxide to form hybrid nanocomposite: enhancement of dielectric properties

Abstract

AbstarctDefects induced graphene oxide-amine functionalized silica hybrid nanocomposite (GO-NH-(CH2)3-SiO2) has been synthesized through sonochemical route with dangling of amine functionalized silica, SiO2-(CH2)3-NH2 on GO. SiO2-(CH2)3-NH2 nanoparticles (dia ∼ 10–15 nm) have been dangled through chemical conjugations at the defective sites of the GO (on one to two layers)/with functional groups to obtain the hybrid nanocomposite. Dielectric properties of defects induced GO-NH-(CH2)3-SiO2 hybrid nanocomposite pellet has been calculated with various frequencies and temperatures. The dielectric constant of the GO-NH-(CH2)3-SiO2 nanocomposite has been encountered to be as high as 730 at 1 KHz which is 36 times higher than that of the free SiO2-(CH2)3-NH2 NPs. The roles of dangling of SiO2-(CH2)3-NH2 on GO and overall functional groups of nanocomposite that lead to such a high dielectric constant have been straightened out. The dielectric constant of the nanocomposite in the range of 20 Hz to 2 MHz and its temperature dependent behaviour in the range of 150 to 400 °C have been elucidated with the apposite governing mechanism. The ac and dc conductivities of the composite have been calculated using impedance measurement and the behaviour observed to be like a semiconducting material. Temperature dependent high dielectric constant of the composite reveals a new era for its use at high temperature. The synthesis method reported here is very easy and economical which can yield large scale production for industrial applications. Further, the findings directed us that the new hybrid composite could be used in designing the high dielectric constant material based electronic and energy storage devices.