Morphology controlled synthesis of ZnO nanostructures by varying pH

Sambath, K.; Saroja, M.; Venkatachalam, M.; Rajendran, K.; Muthukumarasamy, N.

doi:10.1007/s10854-011-0507-6

Cited by 20 publications

(13 citation statements)

References 24 publications

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“…There are two reasons accounting for this result: First, as a kind of strong alkali and weak acid salt, Zn(CH 3 COO) 2 is less acidic than Zn(NO 3 ) 2 and more OH − ions were produced by the hydrolysis process of CH 3 COO − and a high concentration is beneficial for the formation of ZnO nanorods with large diameters . The pH test results showed that the pH values of the initial solution S1 and S2 were 6.67 and 6.61, which are in good accord with the conclusion that an hexagonal rod‐like shape is formed at lower pH values of 5 and 6 . The higher pH value for S1 also confirms the assumption that more OH − anions were generated by the hydrolysis process of CH 3 COO − , which resulted in the formation of a stable alkali environment with a higher concentration of OH − anions.…”

Section: Resultssupporting

confidence: 72%

Precursor‐controlled synthesis of different ZnO nanostructures by the hydrothermal method

Jiao

Bai

et al. 2013

Physica Status Solidi (a)

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Versatile ZnO nanostructures have been fabricated by a two‐step hydrothermal method. Controllable growth of ZnO is feasible by using different kinds of zinc sources. It is revealed by scanning electron microscopy that ZnO nanorods with average diameter 155 nm were synthesized by using Zn(CH3COO)2 as the zinc source. As for the situation when Zn(NO3)2 was used, taper‐like ZnO nanostructure with large aspect ratio was formed. In particular, two‐dimensional ZnO nanosheets can be fabricated when ZnCl2 was introduced and the distinctive X‐ray diffraction spectrum indicates that the anisotropic growth of ZnO along its <0001> direction was hindered, which was caused by the attraction of Cl− ions onto the ZnO polar face instead of growth units. Consequently, the anisotropic growth of ZnO along this direction was hindered, while the other two samples were vertically aligned against the substrates, which can be deduced from their sharp and strong ZnO (002) diffractions. Additionally, their optical properties including the absorptions of ultraviolet light and the corresponding optical bandgaps were also measured by an ultraviolet–visible spectrometer, which changed with the structural transformations. All these properties make them feasible for applications in the fields of both solar cells and biosensors.

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Section: Resultssupporting

confidence: 72%

Precursor‐controlled synthesis of different ZnO nanostructures by the hydrothermal method

Jiao

Bai

et al. 2013

Physica Status Solidi (a)

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“…Indeed, in order to obtain ZnO, many studies used a thermal treatment after the precipitation step [20][21][22][23]. However, the water condensation phenomenom could also appear directly in the solution.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Al doped ZnO nanoparticles by aqueous coprecipitation

et al. 2014

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International audienceAl-doped ZnO particles were obtained by a simple route: soda addition in aqueous cationic solution. The effects of temperature, hydrolysis duration, reagent concentration and time were investigated. A non-topotactic reaction mechanism, involving firstly the precipitation of various hydroxide compounds depending on the route (low or high pH), followed by the dissolution-recrystallization of the hydroxide species into ZnO was demonstrated. The Al concentration in the final ZnO nanopowders did not exceed 0.3 at.% which correspond to the solubility limit of Al in ZnO. The different experimental conditions allow the morphology of ZnO particles to be controlled from isotropic nanoparticles of several tens of nanometers, platelets of several hundreds of nanometers or agglomerates of needle like particles

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“…The UV–vis spectrum in Fig. (A) was used to establish the energy gaps of the ZnOMSs as reported by Sambath et al Using the simplified formula ( αhv ) 2 = r ( hv–E d ), where α = absorption coefficient, E d = energy gap, hv = the photon energy and r = constant. Figure (B) shows a plot of ( αhv ) 2 against hv .…”

Section: Resultsmentioning

confidence: 99%