One-step electrodeposition of Ag-decorated ZnO nanowires

Abstract

Pure and Ag-decorated ZnO nanowires (ZnO NWs) were grown by electrodeposition technique onto ITO conductive glass substrate. A new contribution to the knowledge of Ag dependence of morphological, structural, optical properties is reported, as well as the electrochemical behavior of the ITO/Ag-ZnO NWs electrode/Na 2 SO 4 electrolyte solution interface. X-ray diffraction revealed that the all samples are mainly crystallized in wurtzite ZnO phase. The scanning electron microscopy images show that in the absence or presence of Ag, nanowires appear uniform and stand perpendicular onto substrate with hexagonal shape implying the occurrence of the wurtzite ZnO crystal structure. The presence of Ag nanoparticles is clearly envisioned by EDX spectra. The obtained results According to optical measurements the band gap for undoped ZnO NWs is about 3.25 eV, close to that of ZnO (films, powder and nanorods) 3.36 eV. Optical absorption shows a surface Plasmon resonance effect at 400 nm and 550 nm. Microanalysis confirmed that the amount of Ag in thin solid films is proportional to the Ag content in the starting electrolyte. The increase of Ag-doping results in a decrease of the photoluminescence intensity and blue shift and has been assigned to the Plasmon effect of Ag. Photoelectrochemical measurements showed that the photocurrent increases from 0.05 mA for undoped ZnO NWs to 0.14 mA for the 3% Agdecorated ZnO NWs.

Recent progress in the electrochemical deposition of ZnO nanowires: synthesis approaches and applications

“…However, when ZnO is doped with 3.7% of Ag, a reduction of 10% in the transmittance was reported compared with undoped ZnO 159 . A similar behavior was observed when Ag nanoparticles are used to decorate ZnO nanowires, a reduction in the transmittance of 40-55% was measured when different concentration of Ag were incorporated (from 1 to 3%) to ZnO nanowires 160 .…”

“…The maximum photoelectrochemical response was observed for the maximum Ag concentration (3%). An increment from 0.05 to 0.13 mA•cm -2 was observed under UV illumination 160 . An UV photoresponse of IUVon/IUVoff ~ 1.48 was observed for ZnO:Ag rod-wire.…”

“…Two other peaks were also identified, at ~373 nm due to excite emission, and at 400 nm associated to oxygen vacancies or zinc interstitial defects 171 . For Ag-decorated ZnO nanowires, a red-shift in the band gap is observed and the PL intensity decreases 160 . However, when ZnO nanowires are coated with Ni, the green emission observed in ZnO nanowires is quenched 172 .…”

Photoelectrochemical activity of ZnO:Ag/rGO photo-anodes synthesized by two-steps sol-gel method

“…[33] The decrease of both lattice parameters of ZnO wurtzite structure after doping by Ag is caused by the interstitial incorporation of Ag + into ZnO lattice. [34] While, the increase of the lattice parameters in ZnO:Ag/rGO thin film might be due to the residual stress in the sample or to the lattice strain due to the existence of rGO. [35,36] On the other hand, as can be seen in Fig.…”

Decoration of Ag Nanoparticle on ZnO Nanowire by Intense Pulsed Light and Enhanced UV Photodetector

“…Attempts have been made to improve the properties of ZnO with annealing [24], impurity doping [25], plasma treatment [26], and UV treatment [27]. In addition, Ag NPs were incorporated to improve the properties using thermal techniques [28], UV techniques [29], evaporation [30], sputtering [31], and electrodeposition [32]. Among them, the thermal and UV techniques have employed the solution process.…”