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Electrochemical Study of Under-Potential Deposition Processes on Transition Metal Surfaces

Description: Copper under-potential deposition (UPD) on iridium was studied due to important implications it presents to the semiconductor industry. Copper UPD allows controlled superfilling on sub-micrometer trenches; iridium has characteristics to prevent copper interconnect penetration into the surrounding dielectric. Copper UPD is not favored on iridium oxides but data shows copper over-potential deposition when lower oxidation state Ir oxide is formed. Effect of anions in solution on silver UPD at platinum (Pt) electrodes was studied with the electrochemical quartz crystal microbalance. Silver UPD forms about one monolayer in the three different electrolytes employed. When phosphoric acid is used, silver oxide growth is identified due to presence of low coverage hydrous oxide species at potentials prior to the monolayer oxide region oxide region.
Date: August 2006
Creator: Flores Araujo, Sarah Cecilia
Partner: UNT Libraries

Photophysical studies of silver(I), platinum(II), palladium(II), and nickel(II) complexes and their use in electronic devices.

Description: This dissertation deals with two major topics that involve spectroscopic studies of (a) divalent group 10 metals and (b) silver(I)-phosphine complexes. The scope of the work involved the delineation of the electronic structure of these complexes in different environments and their use in electronic devices. The first topic is a look at the luminescence of tetrahedral silver(I)-phosphine complexes. Broad unstructured emissions with large Stokes shifts were found for these complexes. Computational analysis of the singlet and triplet state geometries suggests that this emission is due to a Jahn-Teller type distortion. The second topic represents the major thrust of this research, which is an investigation into the electronic structure of M(diimine)X2 (M= Pt(II), Pd(II), or Ni(II); X = dichloro, or dithiolate ligands) complexes and their interactions with an electron acceptor or Lewis acid. Chapter 3 assesses the use of some of these complexes in dye sensitized solar cells (DSSCs); it is shown that these complexes may lead to a viable alternative to the more expensive ruthenium-based dyes that are being implemented now. Chapter 4 is an investigation into donor/acceptor pairs involving this class of complexes, which serves as a feasibility test for the use of these complexes in organic photo-voltaics (OPVs) and thin-film field-effect transistors (OTFTs). The mixing of a donor Pt molecule with an electron deficient nitrofluorenone gives rise to new absorption bands in the NIR region. Computational studies of one of the solids suggest that these complexes may have metallic behavior. Chapter 5 demonstrates association in solution, previously unobserved, for Pt(diimine)Cl2 complexes. This chapter is an investigation into the effects of the association mode for this class of complexes on the absorption and emission properties. One of the complexes was used as the emitter in organic light emitting diodes (OLEDs). The results of this study show that these complexes ...
Date: December 2007
Creator: Hudson, Joshua M.
Partner: UNT Libraries

Rediscovery of the Elements: The Platinum Metals

Description: Article describing the history of the platinum metals, from its discovery in the New World and subsequent experiments in Europe. Tourist information is provided regarding areas pertinent to the history of platinum.
Date: Spring 2009
Creator: Marshall, James L., 1940- & Marshall, Virginia R.
Partner: UNT College of Arts and Sciences

Design, Synthesis and Screening of Homoleptic and Heteroleptic Platinum(ii) Pyridylazolate Complexes for N-type Semiconducting and Light-emitting Devices

Description: A series of heteroleptic and homoleptic platinum(II) complexes has been synthesized and characterized towards their use in thin film devices such as organic light-emitting diodes (OLEDs) and organic thin film transistors (OTFTs). Pyridylpyrazolate- and pyridyltetrazolate-containing ligands were selected due to their structural rigidity and ease of functionalization. Single-crystal x-ray diffraction studies of two selected heteroleptic complexes show strong aggregation with preferential stacking into vertical columns with a varying degree of overlap of the neighboring square planar molecular units. It is shown that the close proximity of the molecules to one another in the stack increases semiconducting character, phosphorescence quantum yields, and shorter radiative lifetimes. The potential for these materials towards incorporation into high-efficiency doping free white OLEDs (DFW-OLEDs) for solid-state lighting and display applications has been realized and will be expanded upon by present and future embodiments of materials in this thesis.
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Date: August 2012
Creator: Oswald, Iain William Herbert
Partner: UNT Libraries