Facile large scale solution synthesis of nanostructured iron, nickel and cobalt telluride and possible applications

dc.contributor.advisor Yue Wu
dc.contributor.author Hong, Sungbum
dc.contributor.department Chemical and Biological Engineering
dc.date 2018-08-11T17:46:03.000
dc.date.accessioned 2020-06-30T03:03:02Z
dc.date.available 2020-06-30T03:03:02Z
dc.date.copyright Sun Jan 01 00:00:00 UTC 2017
dc.date.embargo 2017-10-14
dc.date.issued 2017-01-01
dc.description.abstract <p>Transition metal chalcogenides existing in a wide variety of stoichiometries have shown captivating electrical performances. Among them, the earth-abundance and environmental friendliness of iron (Fe), cobalt (Co) and nickel (Ni) chalcogenides have dragged scientists’ attention. Moreover, as state-of-art nanotechnology has impacted on conventional bulk technology in regard to enhancement in performance and discovery of new characteristics, it has been found that nanostructured the Fe, Co and Ni chalcogenides can be exploited for many applications such as superconductor, battery, thermoelectric materials and magnetic material, yet synthesis of these materials has been only accomplished in several milligram scales and normally involved costly equipment and extreme reaction conditions.</p> <p>This thesis proposes facile one-pot solution synthesis methods of nanostructured FeTe2, CoTe and NiTe with over 80% yielding and ~7.0g of final product per batch. An ethylene glycol based system enables a mild reaction condition and short reaction time. The as-synthesized FeTe2 show 1-D nanowires with 26 à  à ± 6nm diameters and a usage of hydrazine for the reaction is appeared to be a key factor to acquire uniform morphology. CoTe and NiTe are synthesized by a one-step reaction. The CoTe 1-D nanorods with uniform thickness of 11 à  à ± 2nm are synthesized only by 5 minutes of reaction and the NiTe 2-D nanoparticles and its conjugated structures with 12 à  à ± 3nm diameters are obtained by 4 hours of reaction. The final solution is further washed, dried and pulverized.</p> <p>The materials powder is spark plasma sintered (SPSed) into disks, and then seebeck coefficient and electrical conductivity are measured. For FeTe2, although it behaves as an intrinsic semiconductor materials, an unusual p-n conduction switching behavior of FeTe2 is observed, which is possibly because of the unintentional tellurium n-type doping generated by thermally expanded cell can attribute to the behavior. As an application of this behavior, a preliminary experiment of thermally controllable p-n junction diode is managed to show a partial success. Meanwhile, the substantially lower seebeck coefficient and higher electrical conductivity in of NiTe and CoTe agree with the highly metallic behaviors, leaving a possible application as dopants for other semiconductor application.</p>
dc.format.mimetype application/pdf
dc.identifier archive/lib.dr.iastate.edu/etd/15321/
dc.identifier.articleid 6328
dc.identifier.contextkey 11051216
dc.identifier.doi https://doi.org/10.31274/etd-180810-4949
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath etd/15321
dc.identifier.uri https://dr.lib.iastate.edu/handle/20.500.12876/29504
dc.language.iso en
dc.source.bitstream archive/lib.dr.iastate.edu/etd/15321/Hong_iastate_0097M_16499.pdf|||Fri Jan 14 20:39:20 UTC 2022
dc.subject.disciplines Chemical Engineering
dc.subject.disciplines Materials Science and Engineering
dc.subject.disciplines Mechanics of Materials
dc.subject.disciplines Nanoscience and Nanotechnology
dc.subject.keywords cobalt telluride nanorod
dc.subject.keywords FeTe2 nanowire
dc.subject.keywords Iron telluride nanowire
dc.subject.keywords nickel telluride nanoparticle
dc.subject.keywords p-n junction diode
dc.title Facile large scale solution synthesis of nanostructured iron, nickel and cobalt telluride and possible applications
dc.type article
dc.type.genre thesis
dspace.entity.type Publication
relation.isOrgUnitOfPublication 86545861-382c-4c15-8c52-eb8e9afe6b75
thesis.degree.discipline Chemical Engineering
thesis.degree.level thesis
thesis.degree.name Master of Science
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