Length Of Zinc Oxide Nanorods Research Articles

Tailoring ZnO nanorods for efficient photocatalytic production of H2O2 from water without sacrificial agents: A study on length optimization

In this study, we investigated the optimal length of zinc oxide nanorods (ZnO NRs) for the production of photocatalytic hydrogen peroxide (H2O2) using a hydrothermal method at 150 °C with reaction times ranging from 2 to 12 h. The study found that the size of the crystals increased when the reaction duration was extended, resulting in an increase in the size from 26 to 48 nm. SEM measurements indicated that ZnO exhibited longitudinal growth along the c-axis, increasing the nanorod length from 1 μm to 3.5 μm. The bandgaps of the ZnO NRs were between 3.21 and 3.25 eV. The optimal conditions for H2O2 production were identified to be 10 min of sonication and 15 min of UV illumination. The generation of H2O2 increased with the dosage of ZnO, ranging from 0.01 to 0.3 g/20 ml. The highest H2O2 production was attained by employing ZnO NRs at 1.6 μm in length with 49 mgL−1 Under UV irradiation and 28 mgL−1 under sonication irradiation. This study offers new perspectives for the design and production of H2O2 using ZnO NRs of a certain length, which may be beneficial for environmental remediation and energy generation.

Fabrication of silver nanodome embedded zinc oxide nanorods for enhanced Raman spectroscopy

Herein, we demonstrate a facile and versatile method to decorate various sizes of silver nanodomes (ZnONR@AgND) along the length of zinc oxide nanorods (AgND) grown over fluorine-doped tin oxide (FTO) substrate. The silver nanodomes (AgND) embedded along the edges of hexagonal zinc oxide nanorods/FTO (ZnONR) substrate were fabricated by using a combination of size selective ZnONR growth and thermal reconstruction. The prepared heterostructure's structural, morphological, and optical behaviors were analyzed by Transmission electron microscopy (TEM), X-Ray diffraction, Raman spectroscopy, field emission scanning electron microscopy (FE-SEM), and UV-Vis spectroscopy. The results confirm the formation of ZnONR@AgND heterostructure with close-packing and construction of the crystalline AgND, adhering to the different faces of the 1D semiconducting ZnONR rods. The AgND size and separation was controlled by the initial sputter thickness and the thermal budget employed during annealing. Insight into the enhanced mechanism for surface-enhanced raman scattering (SERS) activity of ZnONR@AgND was ascertained by probing the hot-spot localization and the enhancement in the electric field by COMSOL simulations and experimentally verified by using rhodamine 6 G (R6G) probe molecules at various concentration 10−3 − 10−12 M. The prepared ZnONR@AgND demonstrated a superior SERS signal (~10 times) due to localization of the hot spots at the AgNDs compared to pure Ag nanoparticles substrate (for 10−6 M). The improved SERS performance of the ZnONR@AgND is attributed to an effective charge transport within the plasmonic AgND, semiconducting ZnO, and the R6G molecule facilitated by the ability of the heterostructure to accommodate multiple hot-spots in a limited volume. This work demonstrates that the SERS activity of semiconductor-based hybrid Raman substrate can be significantly improved by effectively tuning the metal nanoparticle size and density along the length of such hybrid nanowires.

Morphology dependent photocatalytic and magnetic properties of ZnO nanostructures

Zinc oxide (ZnO) nanostructures of different morphology are synthesized by simple soft-chemical approaches. X-ray diffraction and Raman spectra reveal the formation of highly crystalline single-phase hexagonal wurtzite nanostructures of ZnO. TEM micrographs indicate that ZnO nanoparticles are spherical in shape having a size of about 8nm whereas the length of ZnO nanorods are about 30–40nm. SEM micrographs show that ZnO nanoassembly is spherical and porous and is about 100–400nm in size whereas the length of the ZnO microrods are about 4–5µm having a diameter of about 150nm. The ZnO microdiscs are 2–3μm in size. Photoluminescence spectra of the various ZnO nanostructures show that the near band edge emission of ZnO is strongly dependent on their size and shape. Furthermore, the sharp decrease in the intensity of green emission as shape and size changes from nano to microstructures undoubtedly indicates the suppression of oxygen vacancies due to change in the surface to volume ratio i.e. decrease in the surface area from nano to microstructures. Thus, photocatalytic performance of ZnO nanostructures strongly depends on the presence of oxygen vacancies as well as higher surface area. ZnO nanostructures show size, shape and defect concentration dependent ferromagnetic behavior and photocatalytic activity.

Effects of position, thickness, and annealing temperature of Ag buffer layer on the shape of ZnO nanocrystals grown by a simple hydrothermal process

Abstract

Spontaneous and stimulated emission of vertically aligned ZnO nanorods of different lengths

The effect of the length of zinc oxide nanorods on their photoluminescence (PL) has been studied in the visible through UV spectral region. Hexagonally faceted columnar nanorods grown on (100) Si substrates have been shown to be aligned almost vertically. The chemistry of point defects in the nanorods depends on their position in the reactor during growth. The room-temperature PL spectrum of the nanorods shows narrow peaks due to stimulated free-exciton emission. The threshold optical pump power density for lasing in the longer ZnO nanorods is 8000 kW/cm2, and the laser radiation is directed predominantly along their axis.