Enhanced Solar Photoelectrochemical Conversion Efficiency of ZnO:Cu Electrodes for Water-Splitting Application

Abstract

n-typeZnO:Cu photoanodes were fabricated by simple spray pyrolysis deposition technique. Influence of low concentration (range ~10−4–10−1%) of Cu doping in hexagonal ZnO lattice on its photoelectrochemical performance has been investigated. The doped photoanodes displayed 7-time enhanced conversion efficiencies with respect to their undoped counterpart, as estimated from the photocurrents generated under simulated solar radiation. This is the highest enhancement in the solar conversion efficiency reported so far for the Cu-doped ZnO. This performance is attributed to the red shift in the band gap of the Cu-doped films and is in accordance with the incident-photon-current-conversion efficiency (IPCE) measurements. Electrochemical studies reveal ann-typenature of these photoanodes. Thus, the study indicates a high potential of doped ZnO films for solar energy applications, in purview of the development of simple nanostructuring methodologies.

Role of Graphene Oxide as a Sacrificial Interlayer for Enhanced Photoelectrochemical Water Oxidation of Hematite Nanorods

“…A decrease of the micro strain represents a lower number of lattice imperfections and defects. 32,33 The GO-based photoanodes show a 33% lower micro strain compared to the pristine hematite photoanodes.…”

H:ZnO Nanorod-Based Photoanode Sensitized by CdS and Carbon Quantum Dots for Photoelectrochemical Water Splitting

“…[8][9] This, in turn, yields a very low solarto-hydrogen (STH) conversion efficiency. Therefore, broadening the absorption spectrum of ZnO material to the visible or near-IR region, which accounts for about 45% of the whole solar energy spectrum, has been widely studied; for example, doping with metal [10][11][12][13] and nonmetal ions, [14][15] and hydrogenation 6,16 has received extensive attention to improve light absorption and charge transport.…”

Doped Zinc Oxide Nanostructures for Photovoltaic Solar Cells Application

“…Cu/Zn of 1%) was assigned to induce crystallographic defects on ZnO lattices by Cu dopant which reduced the crystalline quality of the film. They observed on the other hand that raising Cu content to 3% enhances the carrier concentration and mobility in the conduction band of the semiconductor [10], thereby lowering the amount of crystallographic defects in the film and increasing the crystalline quality of the film along the ZnO (002) plane [13]. Further increase in Cu content to 5% lowered the crystalline quality of the film sample significantly as indicated in Figure 6, which is an indication of more compressive strain in the films at higher doping level [1,2].…”

“…The choice of a particular technique would be guided by some factors such as the application intended for the synthesis, effectiveness of the technique and cost implication [10,11]. ZnO has been identified as one of the semiconductors with the largest number of novel nanostructures such as nanocombs, nanorings, nanohelixes/nanosprings, nanobelts, nanowires, nanorods, nanotubes, nanocages, etc., with a wide range of technological applications [12][13][14][15]. Novel applications of ZnO nanostructures include optical modulator waveguide, photonic crystals, surface acoustic wave filters, varistors, photodetectors, gas sensors, lightemitting diode, photodiodes and solar cells, amongst others [12].…”

“…Photovoltaic (PV) application of ZnO nanostructures requires large internal surface area with porous and high surface roughness to support good penetration of electrolyte [13,14]. Chemical techniques are very simple, much reliable and cost-effective for the synthesis of high-quality electrodes for PV application.…”