Advanced transition metal phosphide materials from single-source molecular precursors

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dc.contributor.advisorWhitmire, Kenton H.
dc.creatorColson, Adam Caleb
dc.date.accessioned2013-03-08T00:33:10Z
dc.date.available2013-03-08T00:33:10Z
dc.date.issued2012
dc.description.abstractIn this thesis, the feasibility of employing organometallic single-source precursors in the preparation of advanced transition metal pnictide materials such as colloidal nanoparticles and films has been investigated. In particular, the ternary FeMnP phase was targeted as a model for preparing advanced heterobimetallic phosphide materials, and the iron-rich Fe 3 P phase was targeted due to its favorable ferromagnetic properties as well as the fact that the preparation of advanced Fe 3 P materials has been elusive by commonly used methods. Progress towards the synthesis of advanced Fe 2-x Mn x P nanomaterials and films was facilitated by the synthesis of the novel heterobimetallic complexes FeMn(CO) 8 (μ-PR 1 R 2 ) (R 1 = H, R 2 = H or R 1 = H, R 2 = Ph), which contain the relatively rare μ-PH2 and μ-PPhH functionalities. Iron rich Fe 2-x Mn x P nanoparticles were obtained by thermal decomposition of FeMn(CO) 8 (μ-PH 2 ) using solution-based synthetic methods, and empirical evidence suggested that oleic acid was responsible for manganese depletion. Films containing Fe, Mn, and P with the desired stoichiometric ratio of 1:1:1 were prepared using FeMn(CO) 8 (μ-PH 2 ) in a simple low-pressure metal-organic chemical vapor deposition (MOCVD) apparatus. Although the elemental composition of the precursor was conserved in the deposited film material, spectroscopic evidence indicated that the films were not composed of pure-phase FeMnP, but were actually mixtures of crystalline FeMnP and amorphous FeP and Mn x O y . A new method for the preparation of phase-pure ferromagnetic Fe 3 P films on quartz substrates has also been developed. This approach involved the thermal decomposition of the single-source precursors H 2 Fe 3 (CO) 9 PR (R = t Bu or Ph) at 400 °C. The films were deposited using a simple home-built MOCVD apparatus and were characterized using a variety of analytical methods. The films exhibited excellent phase purity, as evidenced by X-ray diffraction, X-ray photoelectron spectroscopy, and field-dependent magnetization measurements, the results of which were all in good agreement with measurements obtained from bulk Fe 3 P. As-deposited Fe 3 P films were found to be amorphous, and little or no magnetic hysteresis was observed in plots of magnetization versus applied field. Annealing the Fe 3 P films at 550 °C resulted in improved crystallinity as well as the observation of magnetic hysteresis.
dc.format.extent204 p.en_US
dc.format.mimetypeapplication/pdf
dc.identifier.callnoTHESIS CHEM. 2012 COLSON
dc.identifier.citationColson, Adam Caleb. "Advanced transition metal phosphide materials from single-source molecular precursors." (2012) Diss., Rice University. <a href="https://hdl.handle.net/1911/70221">https://hdl.handle.net/1911/70221</a>.
dc.identifier.digitalColsonAen_US
dc.identifier.urihttps://hdl.handle.net/1911/70221
dc.language.isoeng
dc.rightsCopyright is held by the author, unless otherwise indicated. Permission to reuse, publish, or reproduce the work beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder.
dc.subjectApplied sciences
dc.subjectPure sciences
dc.subjectAdvanced transition
dc.subjectMetal phosphide
dc.subjectSingle-source
dc.subjectMolecular precursors
dc.subjectFIlms
dc.subjectNanoparticles
dc.subjectInorganic chemistry
dc.subjectMaterials science
dc.titleAdvanced transition metal phosphide materials from single-source molecular precursors
dc.typeThesis
dc.type.materialText
thesis.degree.departmentChemistry
thesis.degree.disciplineNatural Sciences
thesis.degree.grantorRice University
thesis.degree.levelDoctoral
thesis.degree.nameDoctor of Philosophy
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