https://doi.org/10.1140/epjp/s13360-022-03293-3
Regular Article
Effect of pH variations on structural and morphological properties of ZnO nanocrystals
Department of Physics, National Institute of Technology Srinagar, Hazratbal, 190006, Srinagar, Jammu and Kashmir, India
Received:
21
April
2022
Accepted:
12
September
2022
Published online:
28
September
2022
Various ZnO nanostructures were synthesized varying solution pH using sol–gel technique. Zinc acetatedihydrate (0.3 M concentration) was used as the precursor, and triethylene tetramine (0.2 M concentration) was used as surface directing agent. Solution of pH (7.1, 9.0, 10, and 10.5) was carefully adjusted by adding 0.5 M NaOH solution drop wise, until desired pH value occurred. Field emission scanning electron microscope was used to investigate morphological structures. Structural, chemical analysis, optical characterizations were carried out using X-ray diffraction, FTIR, Raman and UV–vis spectroscopic techniques. At solution pH of 7.1, nanospindle-like structure was observed, whereas hollow hexagonal tubes were observed at the solution pH of 9. Furthermore, increasing the pH of the solution to 10 causes the formation of nanomaize-like structures which further transforms into lotus flower-like structure at the solution pH value of 10.5. Flower-like structure is composed of leaves same as that of cone-like structure (with similar dimension) and comparatively better crystallinity with sharp features. X-ray diffraction analysis revealed the growth of wurtzite ZnO phase with the presence of (100), (002) and (101) planes. Ultraviolet–visible analysis (UV–vis) also demonstrated that ZnO nanocrystals have good optical properties with band gap energy (Eg) between 3.17 and 3.27 eV. The further elemental and compositional analysis was done by Raman and FTIR spectroscopy, respectively.
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© The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2022. Springer Nature or its licensor holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.