scholarly journals Effect of Morphology and Plasmonic on Au/ZnO Films for Efficient Photoelectrochemical Water Splitting

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2338
Author(s):  
Mohamed Zayed ◽  
Nourhan Nasser ◽  
Mohamed Shaban ◽  
Hind Alshaikh ◽  
Hany Hamdy ◽  
...  

To improve photoelectrochemical (PEC) water splitting, various ZnO nanostructures (nanorods (NRs), nanodiscs (NDs), NRs/NDs, and ZnO NRs decorated with gold nanoparticles) have been manufactured. The pure ZnO nanostructures have been synthesized using the successive ionic-layer adsorption and reaction (SILAR) combined with the chemical bath deposition (CBD) process at various deposition times. The structural, chemical composition, nanomorphological, and optical characteristics have been examined by various techniques. The SEM analysis shows that by varying the deposition time of CBD from 2 to 12 h, the morphology of ZnO nanostructures changed from NRs to NDs. All samples exhibit hexagonal phase wurtzite ZnO with polycrystalline nature and preferred orientation alongside (002). The crystallite size along (002) decreased from approximately 79 to 77 nm as deposition time increased from 2 to 12 h. The bandgap of ZnO NRs was tuned from 3.19 to 2.07 eV after optimizing the DC sputtering time of gold to 4 min. Via regulated time-dependent ZnO growth and Au sputtering time, the PEC performance of the nanostructures was optimized. Among the studied ZnO nanostructures, the highest photocurrent density (Jph) was obtained for the 2 h ZnO NRs. As compared with ZnO NRs, the Jph (7.7 mA/cm2) of 4 min Au/ZnO NRs is around 50 times greater. The maximum values of both IPCE and ABPE are 14.2% and 2.05% at 490 nm, which is closed to surface plasmon absorption for Au NPs. There are several essential approaches to improve PEC efficiency by including Au NPs into ZnO NRs, including increasing visible light absorption and minority carrier absorption, boosting photochemical stability, and accelerating electron transport from ZnO NRs to electrolyte carriers.

2014 ◽  
Vol 492 ◽  
pp. 311-315
Author(s):  
Bashir Ahmmad ◽  
Kensaku Kanomata ◽  
Fumihiko Hirose

Metal-organic chemical vapor deposition (MOCVD) method has been applied to grow nanostructured ZnO films on Si (100) substrate at temperatures ranging from 200 to 550 °C. The as-prepared films were characterized by XRD, SEM, XPS analysis. The growth rate of ZnO films increases with increasing the deposition temperatures. The deposition temperatures have a drastic effect on the crystallinity and morphology of the nanostructured ZnO. Whisker shaped ZnO is formed at a temperature of 350 °C. The deposition time also affects the morphology of the particles. At 400 °C, sample with one hour deposition forms whisker shaped ZnO nanostructures whereas that of with two hours deposition forms flower-like nanostructures.


2014 ◽  
Vol 602-603 ◽  
pp. 871-875
Author(s):  
Yen Pei Fu ◽  
Jian Jhih Chen

In this study, ZnO films, prepared by Chemical Bath Deposition (CBD), are applied as the conductive layers for thin film solar cells. Zinc acetate is used as a source of zinc, and different proportions of ammonia solution are added and well mixed. The growth of zinc oxide films in reaction solutions is taken place at 80°C and then heated to 500°C for one hour. In this study, the different ammonia concentrations and deposition times is controlled. The thin film structure is Hexagonal structure, which is determined by X-ray diffraction spectrometer (XRD) analysis. Scanning electron microscopy (SEM) is used as the observation of surface morphology, the bottom of the film is the interface where the heterogeneous nucleation happens. With the increase of deposition time, there were a few attached zinc oxide particles, which is formed by homogeneous nucleation. According to UV / visible light (UV / Vis) absorption spectrometer transmittance measurements and the relationship between/among the incident wavelength, it can be converted to the energy gaps (Eg), which are about 3.0 to 3.2eV, by using fluorescence spectroscopy analysis. The emission of zinc oxide films has two wavelengths which are located on 510nm and 570nm. According to Based on the all analytic results, the ammonia concentration at 0.05M, and the deposition time is 120 minutes, would obtain the conditions of ZnO films which is more suitable for applications of conductive layer material in thin film solar cell.


Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4102 ◽  
Author(s):  
Ting Li ◽  
Dongyan Ding

We synthesized Ni/Si-codoped TiO2 nanostructures for photoelectrochemical (PEC) water splitting, by electrochemical anodization of Ti-1Ni-5Si alloy foils in ethylene glycol/glycerol solutions containing a small amount of water. The effects of annealing temperature on PEC properties of Ni/Si-codoped TiO2 photoanode were investigated. We found that the Ni/Si-codoped TiO2 photoanode annealed at 700 °C had an anatase-rutile mixed phase and exhibited the highest photocurrent density of 1.15 mA/cm2 at 0 V (vs. Ag/AgCl), corresponding to a photoconversion efficiency of 0.70%, which was superior to Ni-doped and Si-doped TiO2. This improvement in PEC water splitting could be attributed to the extended light absorption, faster charge transfer, possibly lower charge recombination, and longer lifetime.


2014 ◽  
Vol 875-877 ◽  
pp. 228-231
Author(s):  
Shafique Ahmed Arain ◽  
Christopher Wilkins ◽  
Hafiz Badaruddin

Diethyl dithiocarbamate [Cd (S2CN Et2)2] complex is used to deposit the cadmium sulphide thin film at much lower temperature by Aerosol Assisted Chemical Vapour deposition (AACVD) and same precursor is used to synthesize the nanocrystals in Oleylamine at elevated temperature. Thermogravimetric analysis shows that precursor [Cd (S2CN Et2)2] decomposes in the single stage, losing 62% of total weight. Deposition of thin films at 300°C and 400°C showed the growth of CdS clusters which were made of granular crystallites. These results are confirmed by SEM analysis. Thermolysis of the precursor in oleylamine at 240°C gave the nanoparticles most of them are monodispersed spherical shape, few having mono and dipod structures. TEM images confirm the structures. XRD results show the thin films and nanoparticles have hexagonal phase of CdS.


2018 ◽  
Vol 828 ◽  
pp. 124-136 ◽  
Author(s):  
I. Neelakanta Reddy ◽  
Ch. Venkata Reddy ◽  
Adem Sreedhar ◽  
Jaesool Shim ◽  
Migyung Cho ◽  
...  

2002 ◽  
Vol 730 ◽  
Author(s):  
R. Groenen ◽  
E.R. Kieft ◽  
J.L. Linden ◽  
M.C.M. van de Sanden

AbstractAluminum doped ZnO films are deposited on glass substrates at a temperature of 200°C by expanding thermal plasma CVD. Surface texture, morphology and crystal structure have been studied by AFM, SEM and XRD. A rough surface texture, which is essential for application as front electrode in thin film solar cells, is obtained during deposition. The addition of aluminum as a dopant results in distinct differences in film morphology, a transition from large, rounded crystallites to a more pyramid-like structure is observed. The structure of films is hexagonal with a preferred crystal orientation in the faces (002) and (004), indicating that films are oriented with their c-axes perpendicular to the substrate plane. In addition, spectroscopic ellipsometry is used to evaluate optical and electronic film properties. The presence of aluminum donors in doped films is confirmed by a shift in the ZnO band gap energy from 3.32 to 3.65 eV. In combination with reflection and transmission measurements in the visible and NIR ranges, film resistivities have been obtained from the free-carrier absorption. These results are consistent with direct measurements. Resistivities as low as 6.0 10-4 Ωcm have been obtained.


2021 ◽  
pp. 2109709
Author(s):  
Guijuan Wei ◽  
Yongli Shen ◽  
Xixia Zhao ◽  
Ying Wang ◽  
Weiqing Zhang ◽  
...  

Nanoscale ◽  
2020 ◽  
Vol 12 (23) ◽  
pp. 12292-12299
Author(s):  
Ying-Chu Chen ◽  
Zhi-Jie Wu ◽  
Yu-Kuei Hsu

Anti-reflection enhanced the light harvesting efficiency of a ∼10-μm-long 1D ZnO NRA, which is evidently manifested in the quasi-theoretical photocurrent density that reached ∼0.9 mA cm−2 for solar photoelectrochemical water splitting.


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