Self-assembled arrays of ZnO nanoparticles and their application as varistor materials

Suresh C. Pillai, John M. Kelly*, Declan E. McCormack, Raghavendra Ramesh

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

93 Citations (Scopus)


Linear arrays of ZnO nanoparticles have been successfully prepared by a simple sol-gel condensation reaction involving chemical modifiers, followed by drying (80°C) and calcination (500°C). The calcined material (nano-array ZnO) is composed of approximately spherical nanoparticles of average diameter 21 ± 3 nm, self-assembled to form arrays extending in length to 2-4 μrn. The morphology of the ZnO is found to depend sensitively on the amounts of chemical modifiers present. In their absence the ZnO produced (nano-ZnO) is an unstructured agglomerate of nanoparticles. The mechanism for formation of these linear arrays has been investigated by examining the intermediates formed at 80°C and 250°C using XRD and TEM and by following the decomposition reactions using TGA and DSC. Varistors prepared from the nano-array ZnO by sintering (1050°C) with appropriate mixtures of metal oxides showed a breakdown voltage of 786 ± 30 V mm-1, which is substantially higher than that of samples prepared under similar conditions from either micron-sized commercial ZnO (507 ± 30 V mm-1) or from nano-ZnO (683 ± 30 V mm-1).

Original languageEnglish
Pages (from-to)1572-1578
Number of pages7
JournalJournal of Materials Chemistry
Issue number10
Publication statusPublished - May 21 2004
Externally publishedYes

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Chemistry


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