Optical properties of ZnO nanoparticles synthesized by varying the sodium hydroxide to zinc acetate molar ratios using a Sol-Gel process

Abstract

Material property dependence on the OH−/Zn2+ molar ratio of the precursor was investigated by varying the amount of NaOH during synthesis of ZnO. It was necessary to control the water content and temperature of the mixture to ensure the reproducibility. It was observed that the structural properties, particle size, photoluminescence intensity and wavelength of maximum intensity were influenced by the molar ratio of the precursor. The XRD spectra for ZnO nanoparticles show the entire peaks corresponding to the various planes of wurtzite ZnO, indicating a single phase. UV measurements show the absorption that comes from the ZnO nanoparticles in visible region. The absorption edge of these ZnO nanoparticles are shifted to higher energies and the determined band gap energies are blue shifted as the OH−/Zn2 molar ration increases, due to the quantum confinement effects. The photoluminescence characterization of the ZnO nanostructures exhibited a broad emission band centred at green (600 nm) region for all molar ratios except for OH−/Zn2+ = 1.7 where a second blue emission around 468 nm was also observed. The photoluminescence properties of ZnO nanoparticles were largely determined by the size and surface properties of the nanoparticles.

Effect of annealing temperature on structural, optical, and photocatalytic properties of titanium dioxide nanoparticles

“…Therefore, we can suggest that anatase content decreases with an increase in annealing temperature while rutile content increases. The Debye-Scherrer [ 15 ] Eq. (6) was used to estimate the average crystal size (D) of the TiO 2 nanoparticles.…”

“…Philips Bruker D8 advance X-ray diffractometer, Cu Kα X-ray (λ = 1.5406 Å) was used at 40 kV, 30 mA, at a scanning range of 20–60° to obtain the crystal structure and the phase of the synthesized TiO 2 NPs. Debye-Scherer's equation was used to calculate crystal sizes [ 15 ]. Identification of the crystalline phase was made based on the joint committee powder diffraction standard (JCPDS).…”

Cell-biological effects of zinc oxide spheres and rods from the nano- to the microscale at sub-toxic levels

“…Apart from their unintended presence in the workplace and the environment, zinc oxide particles have many applications in biomedical materials technology, nanomedicine, health care, and consumer products, where the particle parameters play the key role with respect to their physicochemical and biological properties (Ann et al 2015 ; Cheng et al 2013 ). There are different synthetic methods for the preparation of ZnO particles with defined properties, including chemical vapor deposition, sol-gel syntheses, hydrothermal synthesis, and precipitation methods (Amarilio-Burshtein et al 2010 ; Dejene et al 2011 ). Different strategies for the synthesis of ZnO particles in the microscale were reported, but only a few permit the synthesis of monodisperse ZnO particles of different shape in the size range between 50 and 500 nm in a well-dispersed, colloidally stable form (Eskandari et al 2009 ; Nagvenkar et al 2016 ).…”

A Facile Approach for the Preparation of Nano-size Zinc Oxide in Water/Glycerol with Extremely Concentrated Zinc Sources

“…Many methods have been developed to synthesize ZnO nanoparticles with different sizes and morphologies, including chemical vapor deposition [ 11 ], sol-gel methods [ 12 ], hydrothermal methods [ 13 ], laser ablation [ 14 ], microemulsion techniques [ 15 ], and others [ 16 ]. Due to their large specific surface areas as well as high surface energies, ZnO nanoparticles tend to agglomerate easily.…”