Enhanced optoelectronic and supercapacitive performance of electrodeposited Mn3O4 thin film prepared from two-electrode: An effect of Zn-ion incorporation

Abstract

Here in, we report electrodeposited Mn3O4 thin film doped with various level of Zn dopant (0 ≤ 𝑥? ≤ 5.0,%), on a layer of indium tin oxide (ITO) on glass substrate. The deposition route involves the use of two electrode electrochemical cell system comprising graphite and the substrate as counter and working electrodes, respectively. Some surface properties such as those of morphological, crystal structure, optical, electrical and electrochemical were studied to evaluate the films’ potentials in energy conversion and storage devices. Microstructural studies revealed the films grew with isotropic morphology of good tetragonal shaped crystal structure with even distribution and possessing required surface area on the substrate surfaces. Raman prominent peak at 659 cm−1 wave number indicates a typical A1g Raman vibrating mode of Mn2+ in a Mn3O4 spinel structure. The crystallite size and microstrain values were found varying from 38 to 43 nm and 5.6 × 10−3 to 3.2 × 10−3, with respect to increase in dopant content, respectively. Energy band gap and Urbach energy were varied from 3.28 to 2.68 eV and 1.59 to 2.17 eV with increasing level of dopant content, accordingly. Electrochemical charge storage area capacitance (12.62 to 21.35 mF cm−2)/capacity (5.1 to 8.1 μAh cm−2) and rate capability of Mn3O4 electrode were found to improve with Zn dopant. The work therefore discusses the tailoring of band absorption and supercapacitive characteristic of electrodeposited Mn3O4 thin film with Zn-doping for enhanced energy application.