Effects of precursor concentration and reaction time on sonochemically synthesized ZnO nanoparticles

Abstract

The sonochemical reaction between Zn(NO 3 ) 2 and hexamethylenetetramine (HMT) resulted in different products depending on amounts of Zn(II) cations in the aqueous solution. Crystalline phase pure ZnO nanoparticles were obtained by using 0.05 M Zn(NO 3 ) 2 -HMT. This single phase was formed by low power sonication for 20 min in an ultrasonic bath at ambient conditions and its morphology did not change for the next 60 min. Higher concentrations of precursors (0.1 and 0.5 M) led to a mixture of zinc compounds including plate-like Zn 5 (OH) 8 (NO 3 ) 2 (H 2 O). In contrast, a mixed phase ZnO/Zn 5 (OH) 6 (CO 3 ) 2 and a single phase Zn 5 (OH) 6 (CO 3 ) 2 were formed when the precursor concentrations were decreased to 0.01 and 0.005 M, respectively. The resulting infrared absorption and ultraviolet/visible emission were dependent on the phases and defects in these zinc compounds.

Effect of NaOH concentration on optical properties of zinc oxide nanoparticles

“…Intensive studies have been done on various factors, such as precursor concentrations [8,9], temperature [10,11], duration [12], surfactant concentration [7], dopant concentration [6], solvent medium [13], pH of reaction mixture [14] and source of light during synthesis [15], which individually and collectively affect the shape, size and optical properties of ZnO. Various researchers [16][17][18] suggested that NaOH concentration plays a vital role in determining the morphology, size and optical bandgap of obtained nanostructures.…”

Carrier recombination in sonochemically synthesized ZnO powders

“…Based on the above analysis and previously demonstrated strong correlation between the surface defects and optoelectronic properties of ZnO materials [28,[48][49][50], one can expect that the SPV decays would be remarkably different in the SC samples obtained at different stirring times. This is exactly what is seen in Fig.…”

Synthesis and characterization of single phase ZnO nanostructures via solvothermal method: influence of alkaline source

“…This is evident that, despite the simplicity and moderate conditions employed in this study, smaller crystallite sizes could be produced. According to [39], a crystallite size of 21.59 nm and 36.89 nm can be obtained for ZnO from KOH and NaOH, respectively in a sol-gel method. Their reaction time and drying temperature were maintained at 2 hours and 70 o C. In another study by [24], an average crystallite size of 33 nm was recorded in a solvothermal method using Zinc acetate and Triethanolamine (TEA) media.…”