I am working on ZnO nanorods synthesis through hydrothermal method. In literature the common precursors are used for all the nanostructures of ZnO. My question is that why nanorods are formed rather then other nanostructures... Which thing is necessary for the controlling of the alligment(orientation) of ZnO nanorods in hydrothermal method
In our research we have formed films which consisted of flake-shape particles besides nanorod at temperature of 65C. The orientation and shape of nanorods can be controlled mostly by temperature, concentration of precursor, the length of rod - by the time of synthesis.
Morphology of seed-layer is important factor in synthesis of ZnO nanoparticles.
Nanorods is formed rather then other nanostructures due to the wurtzite structure of ZnO.
Hi, crystalline nanostructures are synthesized in solution at low temperature mainly due to the wet-chemical reactions: you would like to read explanation and more informations about that in our recent publication attached here (Chromium inhibition and size-selected Au nanocluster catalysis for the solution growth of low-density ZnO nanowires). Moreover, wet-chemical nanowires usually start to grow from low-energy nucleation sites on substrate, thus, among all, the substrate morphology, material and functionalization (seed-layer ot others) are key-elements in order to achieve well aligned nanowires.
Article Chromium inhibition and size-selected Au nanocluster catalys...
Thanks to every one .. specially to Vito Errico for his paper...Entitle" Chromium inhibition and size-selected Au nanocluster catalysis for the solution growth of low-density ZnO nanowires" . but in this paper you did not mention the thickness of gold seed layer on chromium... How much must be the manimum thickness of Au, and Cr for good quality ZnO nanorods???
Hi, thank you for appreciating our article.
In our article we did not use a continuous layer of gold, but individual nanometric (please see figure3 for dimensions) gold particles on which the nanowires nucleate.
One purpose of the article is to show that it is possible to localize the growth of nanowires at precise nanometric sites where the gold nanoparticles are located, and at the same time to inhibite their growth elsewhere thanks to the layer of chromium. By depositing a thin Au film layer, probably you do not need the layer of Chromium, since all the surface is covered by gold.
As reported in the article, other groups have analysed that the deposition of a uniform layer of gold seems to not be catalytic (NWs growth from solution at low temperature). However we can not exclude that irregularities and very small features in the surface of the gold layer could locally give rise to catalysis effects. Moreover, gold have very good lattice agreement with ZnO, thus with flat gold layer there could be NWs growth with the predominant effects on lattice adaptation rather than on catalysis effects.
Hoping to have clarified your doubt.
Thanks,
Vito.
Hi Ahmed. Thanks for your question. We acquired scanning electron microscope (SEM) pictures of the samples and we analyse them using ImageJ software (Wayne Rasband National Institute of Health USA, http://imagej.nih.gov/ij). ImageJ is a free software tool that after calibration (we use the scale bar in the SEM pictures) permits to measure point-to-point distances in the pictures, and thus the sizes of each singular nanowire. You could read further information on the latest paragraph (“ZnO nanowire densities”) of the supplementary information of the article, attached here for reference. Hoping I have clarified your doubt. Vito
http://www.nature.com/article-assets/npg/srep/2015/150723/srep12336/extref/srep12336-s1.pdf
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