Enhanced photoelectrochemical performance of nanoparticle ZnO photoanodes for water-splitting application

• The thermal evaporation setup has the opportunity to vary source-substrate distance vertically by moving ups and downs the substrate holder.
• The proposed system has the ability to use different size of substrates.
• The deposition time has great influenced on the morphology, crystallinity and Photoconversion efficiency of ZnO photoanodes.
• The ZnO photoanode deposited on 20 min deposition time has better Photoconversion efficiency than the ZnO photoanode deposited on 10 or 30 min.

In this paper, fabrication of ZnO nanoparticle photoanodes for water splitting application is presented. At first, metal zinc films have been deposited on bare fluorine-doped tin oxide glass substrates by thermal evaporation method with chamber pressure 0.05 mbar, source temperature 700 °C and source-substrate distance 3 cm for fabrication of the photoanodes. This deposited zinc films have been annealed at 500 °C for 2 h in atmosphere for obtaining ZnO films. The prepared ZnO films with deposition times (10, 20 and 30 min) are characterized and investigated to find out the photoelectrochemical properties and their suitability for splitting of water. It has been observed that all the ZnO films have high crystallinity wurtzite structure and uniformly distributed nanoparticles with the size of 32–58 nm. ZnO film with 20 min sample has smallest nanoparticles (32 nm) than the others. All the ZnO photoanodes have exhibited higher solar to hydrogen conversion efficiency (0.29–0.42%) than the other researchers data. Among them, ZnO with 20 min sample has been showed maximum efficiency of 0.64% for UV illumination and 0.42% for visible light illumination than the ZnO photoanodes prepared with other deposition times (10 and 30 min).