Improved photoabsorption and refined electrochemical properties of pseudocapacitive CuxO thin film electrode with Zn incorporation for applications in optoelectronic and charge storage

We report the consequence of Zn doping on some surface and electrochemical characteristics of CuxO nanostructured film, obtained via a facile and cost effective two electrode electrochemistry. Impact of Zn dopant on photoabsorption and supercapacitive responses of CuxO thin film electrode was examined. Microstructural studies revealed anisotropic growth of monoclinic and cubic CuxO crystals featuring alternate arrangements of O and Cu ions. Some structural properties of Zn-doped CuxO film were also found varying with Zn content. CuxO film exhibited red shift in its band structure and its optical energy band gap consequently declined from 2.62 to 2.20 eV with increasing Zn dopant. Zn-doped CuxO film also demonstrated highly stable pseudocapacitive response with improved specific capacitance of 263 F g−1 and areal capacity of 5.83 mA h cm−2. Lower series and charge transfer resistances as well as huge ohmic resistivity drop were also observed in the CuxO electrode with Zn dopant, indicating better ionic conductivity and charge storage capability. The study demonstrates successful incorporation of Zn ion in CuxO lattice structure and showed that supercapacitive and photocatalytic properties of CuxO thin electrode can be tailored by simply introducing Zn dopant impurity.