(244e) Nanostructured ZnO Thin Film for Photoelectrochemical Splitting of Water

Abstract: The photoelectrochemical production of hydrogen from water using solar energy has drawn considerable attention due to the importance of using hydrogen as a clean and renewable source. The effectiveness of such a photoelectrochemical cell in converting radiation energy to electricity depends upon the efficiency with which light is absorbed by the photoanode, the number of e^- - h⁺ pairs generated at the photoanode and their separation.

In this study, Nanostructured ZnO thin films supported on conducting substrate was successfully fabricated by sol-gel spin coating method. We present an extensive characterization of the structural, morphological, electrical, optical and electrochemical property of ZnO films to assess the mechanisms of photoelectrochemical behaviour of ZnO thin films. X-Ray diffraction pattern confirmed the prominent evolution of thermodynamic stable hexagonal wurtzite ZnO having band gap 3.16eV. The films were subjected to SEM and AFM to investigate surface morphology and surface topography, respectively. As synthesized film was converted into working electrode and employed in photoelectrochemical cell under varying electrolytic conditions. The films offered high photovoltage and short circuit current. Photocurrent of 1mA was recorded under short circuit condition in aqueous electrolyte at 13pH. To investigate the effect of electrolyte on photocurrent, different electrolytic combinations were tried such as different pH, addition of sacrificial donor and hole scavenger to the electrolyte. It was observed that such additives to the electrolyte play an important role in reduction of electron hole recombination which in turn enhanced the overall photocurrent.