Substrate free ultrasonic-assisted hydrothermal growth of ZnO nanoflowers at low temperature

Abstract

ZnO nanoflowers (NFs) have been synthesised using a simple cost effective ultrasonic-assisted hydrothermal method at low temperature of 95 °C. Here the NFs consist of petal-like arrangement of several hexagonal-shaped nanorods, the length and diameter of which lie in a range of 100-150 nm and 30-70 nm, respectively. ZnO NFs possess hexagonal wurtzite phase, high crystallinity and strong absorption in the UV region. The optical band gap 3.25 eV of these NFs estimated by two different ways is found to be nearly the same. Room temperature photoluminescence spectrum reveals that the ZnO NFs exhibit dominant UV emission and three major emissions in the visible i.e. violet, blue-green and yellow. NFs are promising nanostructures for application in environment related sensors and antimicrobial activity.

Using a Patterned Sapphire Template And The Lift-off Technique To Synthesize ZnO Nanoflower Arrays With Enhanced Photoluminescence Properties

“…We used synthesis time to analyze the properties of ZnO nanorods synthesized on a p-type silicon (Si) < 100 > wafer, as well as the properties of ZnO nano ower arrays synthesized on a prepared patterned substrate. The investigated ZnO nano owers had different shapes from most reported ZnO nano owers, which typically present with prickly sphere-like, rod-like [11], or sea anemone-like morphologies [15]. A series of experiments were performed to investigate the effect of synthesis time on the physical properties, which included the crystal characteristics, morphology, height (or length), diameter, and aspect ratio, and the optical properties, such as the photoluminescence (PL) spectra of the ZnO nanorods and ZnO nano ower arrays.…”

A Novel Synthesis of ZnO Nanoflower Arrays Using a Lift-Off Technique with Different Thicknesses of Al Sacrificial Layers on a Patterned Sapphire Substrate

“…A shortcoming of this research is that they used the expensive GaN/LiAlO 2 substrate and a laser to prepare that substrate. Katiyar et al used the ultrasonic-assisted hydrothermal method to grow the ZnO nanoflowers at a low temperature with no substrate [19]. A shortcoming of this research is that they could not synthesize the ZnO nanoflowers in the array or matrix structure.…”

Investigations of a Statistical and Analytical Method to Find the Relationship between the Morphological and Optical Properties of ZnO Nanoflower Arrays

“… 1 Katiyar et al used the ultrasonic-assisted hydrothermal method to synthesize ZnO nanoflowers at 95 °C, and the nanoflowers were constructed by hexagonal-shaped nanorods to form the petal-like arrangement. 2 Ai et al used a reactive vapor deposition method to synthesize ZnO nanoflowers with the outward appearance of flake petals. 3 The hydrothermal method is a low-temperature process to synthesize ZnO nanomaterials with different structures.…”

“… 13 Katiyar et al used the ultrasonic-assisted hydrothermal method to synthesize ZnO nanoflowers at 95 °C, but apparently, ZnO nanoflowers grew in a versatile direction. 2 However, the problems of these processes are that people have difficulty duplicating the fabrication processes to manufacture the templates and to manufacture ZnO nanoflowers with large areas. Therefore, we investigated a new technology in which the details were described clearly in the paragraph of experimental procedures to synthesize ZnO nanoflowers with an easy process and a large area, because the template could be easily fabricated.…”

“…For example, Huang et al used the vapor–liquid–solid method to synthesize ZnO nanowires, and they could control the diameters of ZnO nanowires by varying the thickness of the Au catalyst film . Katiyar et al used the ultrasonic-assisted hydrothermal method to synthesize ZnO nanoflowers at 95 °C, and the nanoflowers were constructed by hexagonal-shaped nanorods to form the petal-like arrangement . Ai et al used a reactive vapor deposition method to synthesize ZnO nanoflowers with the outward appearance of flake petals .…”