Hydrothermal growth of undoped and boron doped ZnO nanorods as a photoelectrode for solar water splitting applications

Abstract

Abstract: Undoped and boron-doped ZnO nanorods (NRs) were grown on ITO glass substrates by using hydrothermal techniques. The as grown nanorods were investigated by using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), UV–visible spectroscopy, and photoelectrochemical study. XRD spectra reveal the confirmations regarding the hexagonal wurtzite structure along with preferential orientation (002). The observation of (002) peak shows a red shift. The average size distribution of NRs in doped and undoped sample ranges from 169 to 191 nm. The absorption spectra clearly revealed the band gap tunability feature of the samples with a change in doping percentage. Photoluminescence spectra clearly indicate the presence of oxygen defects. Photocurrent density as high as ∼0.622 and 2.6 mA/cm2 were obtained for undoped and 6% B-doped ZnO NRs arrays respectively, at +0.44 V vs. Ag/AgCl electrode under visible light AM 1.5 G (100 mW/cm2) in 0.1 M electrolyte solutions of NaOH. More enhancement in photoconversion efficiency (PCE) from 0.491 to 2.054% was observed for undoped ZnO NRs and optimum 6% B-doped ZnO in 0.1 M NaOH electrolyte solution. Graphical abstract: [InlineMediaObject not available: see fulltext.].