Enhancement of Solar-to-Hydrogen Conversion Efficiency Achieved for Silicon Doped ZnO Nanorods
In the present work, Silicon (Si)-doped Zinc Oxide nanorods (ZnO NRs) were hydrothermally grown on ITO substrates. X-ray diffraction pattern revealed the formation of c-axis oriented hexagonal wurtzite structure nanorods. From the UV-Visible spectra a reduction in optical band gap from 3.25 to 3.21 eV was observed with the incorporation of Si in ZnO host lattice. The Si-doped ZnO NRs sample shows an enhanced photocurrent density of 2.1 mA/cm2 at 0.9 V (vs. Ag/AgCl), as compared to bare ZnO NRs (0.95 mA/cm2) in 0.1 M NaOH aqueous solutions. The results presented an enhanced solar-to-hydrogen conversion efficiency of 121% by using silicon as a dopant. With introduction of Si4+ ion into ZnO host more number of carriers are generated which may be accounted for this enhancement. The results henceforth recommends the suitability of Si-doped ZnO NRs as an efficient active photo electrode material in liquid junction photoelectrochemical applications.
The authors would like to thank IIT(ISM), Dhanbad, India for providing research fellowship and Central Research Facility (CRF) respectively. The authors sincerely thank to the Ministry of Human Resource and Development project under the scheme-Establishment of Centre of Excellence for Training and Research in Frontier Areas of Science and Technology (FAST) in Renewable Energy vide letter F. No. 5-5/2014-TS.VII dated 04.09.2014.