The Effect of the Solution Flow and Electrical Field on the Homogeneity of Large-Scale Electrodeposited ZnO Nanorods.

In this paper, we demonstrate the significant impact of the solution flow and electrical field on the homogeneity of large-scale ZnO nanorod electrodeposition from an aqueous solution containing zinc nitrate and ammonium nitrate, primarily based on the X-ray fluorescence results. The homogeneity can be enhanced by adjusting the counter electrode size and solution flow rate. We have successfully produced relatively uniform nanorod arrays on an 8 × 10 cm2 i-ZnO-coated fluorine-doped tin oxide (FTO) substrate using a compact counter electrode and a vertical stirring setup. The as-grown nanorods exhibit similar surface morphologies and dominant, intense, almost uniform near-band-edge emissions in different regions of the sample. Additionally, the surface reflectance is significantly reduced after depositing the ZnO nanorods, achieving a moth-eye effect through subwavelength structuring. This effect of the nanorod array structure indicates that it can improve the utilization efficiency of light reception or emission in various optoelectronic devices and products. The large-scale preparation of ZnO nanorods is more practical to apply and has an extremely broad application value. Based on the research results, it is feasible to prepare large-scale ZnO nanorods suitable for antireflective coatings and commercial applications by optimizing the electrodeposition conditions.

Enhancement of electrochemical detection performance towards 2,4,6-trinitrotoluene by a bottom layer of ZnO nanorod arrays.

The ZnO nanostructure layers have been widely investigated as electrodes for sensors due to their intrinsic advantages such as high active area and low cost. In this work, to enhance the detection properties of ZnO nanostructural electrodes, self-organized ZnO nanorod arrays were synthesized using the chemical bath deposition (CBD) method on FTO glasses and ZnO nanoparticles. The fabricated ZnO electrodes on the two different substrates were characterized by SEM, TEM, XRD, and XPS. Subsequently, the detection performance of ZnO nanorod electrodes was electrochemically measured in a 2,4,6-trinitrotoluene (2,4,6-TNT) solution by CV and EIS. The differences in current densities between the ZnO electrodes were determined by the width of the ZnO nanorods, resulting in a ∼45% higher detection efficiency with F-CBD (the ZnO nanorods on FTO) electrodes compared to S-CBD (the ZnO nanorods on ZnO nanoparticles) electrodes.

Nanoscale electrical properties of ZnO nanorods grown by chemical bath deposition.

Well-aligned zinc oxide nanorod arrays (ZNAs) synthesized using chemical bath deposition were fabricated on a gallium-doped zinc oxide substrate, and the effects of varying the precursor concentrations on the growth and nanoscale electrical properties of the ZNAs were investigated. The as-synthesized ZNAs were characterized using field-emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), conducting atomic force microscopy (CAFM), and scanning surface potential microscopy (SSPM). The FESEM and AFM images show that the growth rate in terms of length and diameter is highly sensitive to the precursor concentration. CAFM and SSPM analyses indicate that when concentrations of both the zinc acetate and hexamethylenetetramine solutions were 30 mM, the coverage percentages of the recordable and conducting regions on the ZNA surface were 48.3% and 0.9%, which is suitable for application in resistive random access memory devices.