Tuning Transparent Supercapacitor Performance by Controlling the Morphology of its ZnO Electrodes

Transparent supercapacitors were fabricated using nanostructures ZnO electrodes deposited using reactive magnetron sputtering. By fine tuning the deposition process parameters the electrodes with different morphologies were obtained, from hierarchical through sponge-like to nanocolumnar. The device performance related to the electrode morphology was assessed. It was found that the nanocolumnar electrodes provided best performance both in terms of effective device capacitance (18.3 μF/cm²) and transparency ( ≈ 100% in the visible range). The worst performance, with 80% lower effective capacitance, was obtained in the devices with the sponge-like morphology.