Dielectrics of graphene oxide decorated with nanocomposite silica-coated calcium copper titanate (CCTO) nanoparticles

Abstract

This work presents the synthesis of the noble nanocomposites of silica-coated calcium copper titanate–graphene (CCTO@SiO2–GO) by the established sol–gel method. This paper showed the decoration of CCTO@SiO2 NPs on the surface of graphene oxide and how the decoration/attachment depends on various environmental and instrumental factors like sonication time, stirring rate, centrifugation rpm and the thickness of silica shell coated on CCTO NPs. The prepared CCTO@SiO2–GO composites were characterized by suitable characterization techniques. FESEM and TEM confirmed the morphological study of nanocomposites and how the CCTO@SiO2 NPs are attached to the surface of GO sheet. FTIR has shown the presence of O–H, N–C groups which help in the formation of types of bonds between CCTO@SiO2 NPs and GO. This work further revealed an excellent result of a dielectric study, indicating that the best-decorated CCTO@SiO2 NPs over the surface of the GO sheet cause the increment of dielectric constant e′ from 102 up to 105. Meanwhile, this study also suggested high loss e″ up to 106 at a lower frequency, i.e. 20 Hz at RT which can be useful for microelectronic devices. This variance of dielectrics is due to the effect of polarization and decoration of CCTO@SiO2 NPs over the GO sheets. As the frequency increases from 20 Hz to 2 MHz, the dielectric constant e′, as well as the loss of e″, reached up to 102 values for the highest decorated material. Our study also clearly explained a uniform variation in dielectric constant ranges from 1 × 102 to 1.5 × 104 at a different temperature range from room temperature to 560 °C with a frequency range of 3 × 104 Hz to 2 × 106 Hz, and the value varies accordingly with the synthesis method.