Fabrication of heterostructure NiO/ZnO thin film for pseudocapacitor application

Abstract

An ordered NiO/ZnO heterojunction electrochemical electrode was prepared on an FTO substrate by using the spin-coating method. XRD patterns confirmed the ZnO NRs of varying lengths and NiO NPs of varying sizes are grown in the same manner as hexagonal wurtzite and cubic crystal structures, respectively. An important outcome is that both the crystal structures are fused together as a heterostructure film. Almost all Zn, Ni and O atoms primarily involved in forming heterostructure films are strongly observed. Furthermore, the charge carrier transition from the conduction band edge and/or localised defect state to the valance band edge is measured by photoluminescence spectra. Eventually, it is perceived that p-type NiO/ZnO heterostructure film has ferromagnetism, whereas n-type ZnO and p-type NiO films have weak FM and superparamagnetism. The GCD of the NiO/ZnO thin film electrode display a pseudocapacitive behaviour. A maximum Csp of 114 F/cm(3) is obtained from both the CV and GCD studies, which are mainly attributed to the morphological characteristics of nanorod and nanoparticle self-assembling architectures, as well as a rational composition of the two constituents. The experimental results reveal that the spin-coated NiO/ZnO thin films are promising materials for electrochemical supercapacitors. [GRAPHICS] .