Hybrid organic-inorganic layered electronic materials : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Physics at Massey University, Manawatu campus, New Zealand
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Date
2012
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Massey University
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Abstract
Hybrid organic-inorganic materials combine distinct features of organic and inorganic
components into single molecular frameworks that exhibit tunable electronic, optical and
magnetic properties. An extending layered network is formed by covalently bound layers of
inorganic materials that are electronically coupled by organic components. A control on the
stacking orientation of these layers can help tailor the structural, physical and chemical
properties of resulting compounds.
This thesis presents an investigation of the synthesis, characterization and effects of
doping, primarily by ion-implantation, on structural, chemical and physical properties of
transition-metal oxide based organic-inorganic hybrid materials. These materials were
synthesized and characterized by a variety of experimental techniques. The crystal structures
of these compounds were probed by powder and single-crystal X-ray diffraction while
various other techniques such as Raman spectroscopy, X-ray photoelectron spectroscopy,
magnetic and resistivity measurements were applied to examine the chemical and physical
properties of these materials. The crystal structure of these materials consists of infinite layers
of transition metal oxides interlinked by organic ligands. The organic-ligands are aligned so
as to define small cages within these structures, potentially, to accommodate metal ions.
Intercalation of alkali-metal atoms within these cages brings about important altercations in
the structural, chemical and physical properties of these materials. The presence of
intercalated species was confirmed by single-crystal X-ray diffraction and X-ray
photoelectron spectroscopy while spectral changes observed from Raman measurements and
a significant reduction in electrical resistance of implanted materials refer to charge carrierinjection
into the conduction band.
Significant changes in structure and physical properties of these materials were
observed by increasing the number of atoms in ligand tethers while introduction of additional
metal atoms, by in-situ doping, in the inorganic oxide layers, leads to strong
antiferromagnetic interactions in otherwise diamagnetic materials. These results demonstrate
the possibilities of exploiting the self-assembly of organic and inorganic precursors to realize
the potential applications these materials have to offer.
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Keywords
Organic materials, Inorganic materials, Hybrid materials, Electronic materials, Materials