Physical Sciences and Mathematics Commons^™

Development Of Acceptor-Integrated Crystalline Organic Materials, Brandon Yarbrough

Theses and Dissertations

We report the first example of fullerene-containing porous covalent-organic scaffold, which combines not only crystallinity and porosity, but also integrates the intrinsic properties of a redox-active buckyball, along with the ability to tune electronic properties. Thus, the presented studies not only demonstrate the possibility of merging the strong electron accepting properties of fullerene-based derivatives with the versatility of covalent-organic frameworks (COFs), but also begin the class of crystalline, entirely organic, donor-acceptor fullerene COFs through covalently modifying the channel walls. These studies could foreshadow new avenues for buckyball utilization for applications ranging from organic photovoltaics to molecular electronics.

Photo-Induced Charge Transport In Graphene And Semiconducting Wse2 Integrated With Zero-Dimensional Materials For Enhancing Optoelectronic Device Characteristics, Srishti Chugh

Open Access Theses & Dissertations

Two-dimensional (2D) materials encompass a diverse array of properties from the metallic-like character of graphene to the semiconducting nature of many of the transition metal dichalcogenides (TMDCs) such as tungsten diselenide (WSe2). These materials exhibit intriguing interactions with incoming radiation which makes them interesting for electronics and optoelectronics, especially given the high electron mobility and the ballistic nature of the electronic transport under certain conditions. In particular, the semiconducting TMDCs, such as WSe2, express an indirect-to-direct optical transition with scaling from the bulk to monolayers. Despite the enhanced optical absorption characteristics of monolayer WSe2 stemming from its direct band gap, …

Tridecacyclene: Synthesis And Structural Properties Of Non-Planar Polycyclic Aromatic Hydrocarbons And Studies Towards A Fragment Of The Fullerene C240, Daniel Sumy

Graduate College Dissertations and Theses

While investigating strategies to prepare precursors to highly strained buckybowls, we focused our attention on the Lewis acid aldol cyclization of 1-acenaphthenone derivatives which has been shown to produce a cyclic tetramer as a byproduct. Surprisingly, despite the interesting structural and electronic properties that have recently been observed as a result of the incorporation of eight-membered rings into polycyclic aromatic hydrocarbons, this cyclic tetramer has largely been ignored. As a result of this, we set our sights on the isolation and characterization of this cyclic tetramer.

The initial approach employed subjecting 1-acenaphthenone to the most common conditions used in trimerization—TiCl4 …

Preparation And Characterization Of Singlet-Oxygen Generating Thiol-Ene Networks Containing Fullerene And Metallofullerene Derivatives, Emily Matthews Barker

Dissertations

This work explores the derivatization of C₆₀ and Sc₃N@C₈₀ with S-, P-, and C- centered radicals, and is the first exploration into the functionalization of Sc₃N@C₈₀ with sulfur and phosphorous. The number of addends bound to C₆₀, as a function of reaction time and molar ratios, as well as, structure-property relationships including thermal stability, solubility, and singlet oxygen generation were explored. Fullerene derivatives exhibiting enhanced solubility were incorporated into two different thiol-ene polymer matrices at varying thiol-ene monomer concentrations (1:1 or 1:0.75 molar equivalents) and at different C₆₀ loadings (0, …

Environmental Fullerene Chemistry: Elucidating Critical Reaction Pathways And Resulting Products In The Aqueous Phase, Jiewei Wu

McKelvey School of Engineering Theses & Dissertations

As the production of fullerenes and fullerene-based materials approaches industrial scale, there are increasing interests/concerns regarding their (potential) environmental impact(s) upon release. To date, a number of critical, aqueous-based fullerene transformation pathways under environmentally relevant conditions remain poorly understood. Comprehensive, fundamental, and quantitative understanding of the potential (major) reaction pathways and resulting products of fullerene materials, particularly in aquatic systems, is now crucial for their accurate fate, transport, life cycle, risk assessment(s), and thus ultimate material sustainability.

Herein, this dissertation is focused on identifying and elucidating aqueous transformation pathways of fullerene materials, focused on C60 as a model fullerene, under …

Synthesis And Characterization Of "Click Inspired" Thiol-Ene-Fullerene Nanocomposites, Amber Danielle Windham

Dissertations

This work explores the covalent incorporation of C₆₀ and Sc₃N@C₈₀ fullerenes into thiol-ene networks by a facile, one-pot photochemical reaction with multifunctional thiol and alkene monomers. Synthesis of disulfide bonds within the tri-functional thiol monomer served to photochemically initiate the reaction when cleaved. This was followed by thermal curing of the pre-polymer for preparation of fullerene-containing thiol-ene films. Films were characterized by standard techniques including infrared spectroscopy, gel percent, and thermogravimetric analysis. The role of C₆₀ and Sc₃N@C₈₀ as suitable alkenes for free-radical reaction with multifunctional thiols was investigated by preparing a …

Highly Fluorinated, Coinage Metal Complexes Of Tris(Pyrazolyl)Borates With Additional Electron Withdrawing Groups And Pyrazolate Π-Stackings With Arenes, Naleen Bandupriya Jayaratna

Chemistry & Biochemistry Dissertations

Tris(pyrazolyl)borates are very popular ligands in inorganic chemistry, bioinorganic chemistry, and organometallic chemistry due to their attractive properties. It is possible to extensively modify the steric and electronic properties of these ligands by changing the pyrazolyl substituent groups. Taking into account the importance and current interest of fluorinated tris(pyrazolyl)borates and weakly coordinating anions in general, three new tris(pyrazolyl)borates, [HB(4-Cl-3,5-(CF₃)₂Pz)₃]-, [HB(3,4,5-(CF₃)3Pz)₃] and [HB(4-(NO₂)-3,5-(CF3)₂Pz)₃]- have been developed (Pz = pyrazolyl). Silver alkene adducts of the ligands have been isolated to evaluate the electronic properties of the ligands and to study their catalytic properties. These adducts found to be the most electron deficient …

Triphenylamine-, Porphyrin- And Fullerene-Based Derivatives For Photovoltaic And Other Applications, Danisha Marie Rivera Nazario

Open Access Theses & Dissertations

Proper collection of charges at the electrodes is an important process in organic solar cells. Interfacial layers between the electrodes and the photoactive layer have been design to improve charge collection and ohmic contacts. The most studied interfacial layer between the anode and the photoactive layer is the negatively charged polymer poly(3,4-ethylendioxythiophene):poly(styrenesulfonate) (PEDOT:PSS), that possesses good hole transporting ability. However, inhomogeneities at the surface of the electrode after deposition of the polymer lower the stability and performance of the OPV devices. Triphenylamine (TPA) derivatives have received increased attention in the organic solar cells (OSCs) field because of their favorable light …

Design And Synthesis Of Polymer-Based Advanced Nanomaterials Using Raft Polymerization And Click Reaction, Junting Li

Theses and Dissertations

This research focuses on exploring new synthetic approaches to prepare polymer-based advanced nanomaterials using highly efficient chemical tools, such as reversible addition-fragmentation chain transfer (RAFT) polymerization and click reactions.

In the first project, novel synthetic routes to produce fullerene-based polymers were designed. First, mono-alkynyl functionalized fullerene was prepared starting with pristine fullerene (C₆₀). Methyl methacrylate and 6-azido hexyl methacrylate were then randomly copolymerized via RAFT polymerization with well-controlled molecular weights and copolymer compositions. Finally, the two moieties were covalently assembled into a series of well-defined side-chain fullerene polymers (SFP's) via the copper-catalyzed click reaction. The TGA and UV-vis …

Synthesis And Characterization Of Acceptor: Donor Block Copolymers For Organic Photovoltaics, Brandon Cory Achord

Dissertations

Mankind needs sources of clean power. Photovoltaic (PV) cells, in use since 1839, have proven reliable and practical for certain applications. PV cell efficiency has changed over the years from 1-2% to ultra-high efficiency cells operating at efficiencies greater than 40%. Organic photovoltaics are a potential transformative technology platform. The potential for cell use, efficiency and cost are all parts of the research and development focus at the time this document was written. This research was initiated with a focus on the synthesis and understanding of the variables effecting acceptor-donor block copolymer. The self-assembled morphology resulting from varying volume ratios …

Physical And Electrical Properties Of Trimetallic Nitride Template Endohedral Metallofullerenes And Their Polymer Nanocomposites, Hanaa Mohammed Ahmed

Dissertations

The main objective of this study was characterization of pure metallic nitride fullerene, MNF, and MNF containing polymers to evaluate these materials as suitable devices for tunable applications. Polymer-fullerene nanocomposites consisting of linear polyurethane (PU) segments crosslinked via polyhydroxylated fullerenes (C₆₀ and Sc₃N@C₈₀, a metallic nitride fullerene) were prepared and characterized for their mechanical and dielectric properties using dynamic mechanical analysis (DMA) and broadband dielectric spectroscopic techniques. Polyhydroxylated fullerenes C₆₀(OH)₂₉ and Sc₃N@C₈₀(OH)₁₈ were synthesized in a high yield through a solid-state high sheer ball-milling procedure and were …

Design And Regioselective Synthesis Of Two And Three-Pronged C60 Fullerene Derivatives And Their Applications In Molecular Electronics, Angy Ortiz-Hernandez

All Dissertations

Since the introduction of semiconductors in the second half of the 20th century, advancements in electronics and technology have been tremendous. In particular, the rapid development of silicon-based computer chip technology and miniaturization of electronic components has been tremendous. Since silicon-based materials have a limit in terms of size, scientists proposed that individual molecules could behave as single electronic components for high degree of miniaturization.
Given that the molecules of interest must have dimensions on the nanometer scale, be able to bind to the electrode surface and have electron donor-acceptor properties, C₆₀ fullerene has been a prime candidate for …

Synthesis Of Trimetallic Nitride Endohedral Metallofullerene Derivatives For Enhanced Solar Energy Conversion, Julio Pinzon Joya

All Dissertations

The preparation and electrochemical properties of donor - acceptor systems based on trimetallic nitride endohedral metallofullerenes (TNT-EMFs) for enhanced solar energy conversion is described. It was found that TNT-EMFs have an enhanced ability to stabilize charge separated states formed upon light irradiation when compared to empty cage fullerene analogues. The influence of the linker connecting the donor and acceptor moieties was studied in two different systems. Optimal conditions for preparing cyclopropanated Bingel-Hirsch derivaties of the most common TNT-EMFs were found; this functionalization approach is a very useful alternative to the 1,3-dipolar cycloaddition reactions that yield pyrrolidine derivatives, because the latter …

Development Of Fullerene Based Sturctures For Photovoltaic And Electronic Applications, Amit Palkar

All Dissertations

Solar energy can be envisioned as a long term alternative to rapidly depleting fossil fuels. The energy from the sun can be harnessed by constructing donor-acceptor (D-A) type devices where the incident photon induces the transfer of an electron from the donor to the acceptor. If recombination is prevented, this electron can then be channeled through an external circuit, thus leading to the generation of photocurrent. Porphyrins, which are the naturally occurring pigments in photosynthesis, have been widely established as donors while fullerenes, such as C₆₀ and C₇₀ , due to their unique electron accepting properties, have been …