Nanoscience and Nanotechnology Commons^™

Exploring The Silent Aspect Of Carbon Nanopores, Teresa J. Bandosz

Publications and Research

Recently, owing to the discovery of graphene, porous carbons experienced a revitalization in their explorations. However, nowadays, the focus is more on search for suitable energy advancing catalysts sensing, energy storage or thermal/light absorbing features than on separations. In many of these processes, adsorption, although not emphasized sufficiently, can be a significant step. It can just provide a surface accumulation of molecules used in other application-driving chemical or physical phenomena or can be even an additional mechanism adding to the efficiency of the overall performance. However, that aspect of confined molecules in pores and their involvement in the overall performance …

In Depth Characterisation Of The Biomolecular Coronas Of Polymer Coated Inorganic Nanoparticles With Differential Centrifugal Sedimentation, André Perez-Potti, Hender Lopez, Beatriz Pelaz, Abuelmagd Abdelmonem, Mahmoud G. Soliman, Ingmar Schoen, Philip M. Kelly, Kenneth A. Dawson, Wolfgang J. Parak, Zeljka Krpetic, Marco P. Monopoli

Articles

Advances in nanofabrication methods have enabled the tailoring of new strategies towards the controlled production of nanoparticles with attractive applications in healthcare. In many cases, their characterisation remains a big challenge, particularly for small-sized functional nanoparticles of 5 nm diameter or smaller, where current particle sizing techniques struggle to provide the required sensitivity and accuracy. There is a clear need for the development of new reliable characterisation approaches for the physico-chemical characterisation of nanoparticles with significant accuracy, particularly for the analysis of the particles in the presence of complex biological fluids. Herein, we show that the Differential Centrifugal Sedimentation can …

3-D Fabry–Pérot Cavities Sculpted On Fiber Tips Using A Multiphoton Polymerization Process, Jonathan W. Smith, Jeremiah C. Williams, Joseph S. Suelzer, Nicholas G. Usechak, Hengky Chandrahalim

Faculty Publications

This paper presents 3-D Fabry–Pérot (FP) cavities fabricated directly onto cleaved ends of low-loss optical fibers by a two-photon polymerization (2PP) process. This fabrication technique is quick, simple, and inexpensive compared to planar microfabrication processes, which enables rapid prototyping and the ability to adapt to new requirements. These devices also utilize true 3-D design freedom, facilitating the realization of microscale optical elements with challenging geometries. Three different device types were fabricated and evaluated: an unreleased single-cavity device, a released dual-cavity device, and a released hemispherical mirror dual-cavity device. Each iteration improved the quality of the FP cavity's reflection spectrum. The …

Surface Enhanced Raman Spectroscopy (Sers) As A Nanoscale Adsorption Phenomenon: Development Of Tailored Nanomaterials For Applications In Drug Detection, Chiara Deriu

FIU Electronic Theses and Dissertations

Surface Enhanced Raman Spectroscopy (SERS) is an analytical technique in which nanostructured substrates amplify the inherently weak Raman signal of an adsorbed species by several orders of magnitude, enabling the detection of trace compounds, up to the single molecule level. While this may be an exceptional tool for any analytical scientist, SERS is at present relegated to the role of academic sensation, and is underutilized in everyday analytical practice. The SERS community is increasingly attributing this setback to a poor understanding of nanoscale surfaces and their chemical environment; since molecular adsorption at the nanostructured surface enables SERS detection, uncertainty about …

Nanoscale Colocalization Of Fluorogenic Probes Reveals The Role Of Oxygen Vacancies In The Photocatalytic Activity Of Tungsten Oxide Nanowires, Meikun Shen, Tianben Ding, Steven T. Hartman, Fudong Wang, Christina Krucylak, Zheyu Wang, Che Tan, Bo Yin, Rohan Mishra, Matthew D. Lew, Bryce Sadtler

Electrical & Systems Engineering Publications and Presentations

Defect engineering is a strategy that has been widely used to design active semiconductor photocatalysts. However, understanding the role of defects, such as oxygen vacancies, in controlling photocatalytic activity remains a challenge. Here, we report the use of chemically triggered fluorogenic probes to study the spatial distribution of active regions in individual tungsten oxide nanowires using super-resolution fluorescence microscopy. The nanowires show significant heterogeneity along their lengths for the photocatalytic generation of hydroxyl radicals. Through quantitative, coordinate-based colocalization of multiple probe molecules activated by the same nanowires, we demonstrate that the nanoscale regions most active for the photocatalytic generation of …

Hybrid Electrochemical Capacitors: Materials, Optimization, And Miniaturization, Richa Agrawal

FIU Electronic Theses and Dissertations

With the ever-advancing technology, there is an incessant need for reliable electrochemical energy storage (EES) components that can provide desired energy and power. At the forefront of EES systems are electrochemical capacitors (ECs), also known as supercapacitors that typically have higher power and superior cycle longevity but lower energy densities than their battery counterparts. One of the routes to achieve higher energy density for ECs is using the hybrid EC configuration, which typically utilizes a redox electrode coupled with a counter double-layer type electrode.

In this dissertation, both scale-up (coin-cell type) as well as scale-down (on-chip miniaturized) hybrid ECs were …

Catalyzed Synthesis Of Zinc Clays By Prebiotic Central Metabolites, Marcelo I. Guzman, Ruixin Zhou, Kaustuv Basu, Hyman Hartman, Christopher J. Matocha, S. Kelly Sears, Hajatollah Vali

Chemistry Faculty Publications

How primordial metabolic networks such as the reverse tricarboxylic acid (rTCA) cycle and clay mineral catalysts coevolved remains a mystery in the puzzle to understand the origin of life. While prebiotic reactions from the rTCA cycle were accomplished via photochemistry on semiconductor minerals, the synthesis of clays was demonstrated at low temperature and ambient pressure catalyzed by oxalate. Herein, the crystallization of clay minerals is catalyzed by succinate, an example of a photoproduced intermediate from central metabolism. The experiments connect the synthesis of sauconite, a model for clay minerals, to prebiotic photochemistry. We report the temperature, pH, and concentration dependence …

Metal-Organic Hybrid Nanocomposites For Energy Harvesting Applications, Thulitha Madawa Abeywickrama

Masters Theses & Specialist Projects

Various synthetic methods have been developed to produce metal nanostructures including copper and iron nanostructures. Modification of nanoparticle surface to enhance their characteristic properties through surface functionalization with organic ligands ranging from small molecules to polymeric materials including organic semiconducting polymers is a key interest in nanoscience. However, most of the synthetic methods developed in the past depend widely on non-aqueous solvents, toxic reducing agents, and high temperature and high-pressure conditions. Therefore, to produce metal nanostructures and their nanocomposites with a simpler and greener method is indeed necessary and desirable for their nano-scale applications. Hence the objective of this thesis …

Visible-Light-Responsible Co-Catalysts Enhanced By Graphene For Solar Energy Harvesting, Chen Ying

Masters Theses & Specialist Projects

This study focuses on the visible light response of hetero-structures of TiO2-graphene- MoS2 for solar energy harvestings. The commercial P25 TiO2 nano-particles, and selfprepared layered reduced graphene oxides (RG) and MoS2 were assembled for the targeted hetero-structure materials as visible-light responsible solar harvesting cocatalysts. The hydrothermal method was applied for nano-material synthesis, the reduction of graphene oxides, and bonding formation. Multiple characterization methods (SEM-TEM, XRD, XPS, UV-VIS, PL, FT-IR, TGA) have been applied to understand the electron-hole pair separation and recombination, and performance tuning in their visible-light photo-catalysis rhodamine B (Rh.B) degradations process

Compared to TiO2, an obvious red shift …

Molecular Helices As Electron Acceptors In High-Performance Bulk Heterojunction Solar Cells, Yu Zhong, M. Tuan Trinh, Rongsheng Chen, Geoffrey E. Purdum, Petr P. Khlyabich, Melda Sezen, Seokjoon Oh, Haiming Zhu, Brandon Fowler, Boyuan Zhang, Wei Wang, Chang-Yong Nam, Matthew Y. Sfeir, Charles T. Black, Michael L. Steigerwald, Yueh-Lin Loo, Fay Ng, X.-Y. Zhu, Colin Nuckolls

Publications and Research

Despite numerous organic semiconducting materials synthesized for organic photovoltaics in the past decade, fullerenes are widely used as electron acceptors in highly efficient bulk-heterojunction solar cells. None of the non-fullerene bulk heterojunction solar cells have achieved efficiencies as high as fullerene-based solar cells. Design principles for fullerene-free acceptors remain unclear in the field. Here we report examples of helical molecular semiconductors as electron acceptors that are on par with fullerene derivatives in efficient solar cells. We achieved an 8.3% power conversion efficiency in a solar cell, which is a record high for non-fullerene bulk heterojunctions. Femtosecond transient absorption spectroscopy revealed …

Effect Of Surface Omniphobicity On Drying By Forced Convection, Madani A. Khan, Jeffrey Alston, Andrew Guenthner

STAR Program Research Presentations

Low energy surfaces can strongly repel both oil and water. Recently these surfaces have been fabricated on various substrates including fabric, aluminum, stainless steel and many other materials. In this experiment we explore the use of low energy surface deposition on aluminum alloy, stainless steel and silicon substrates, to enhance the drying rate of liquids removed from the surface by forced convection. We control surface roughness by substrate abrasion and by the growth of Al₂O₃ nanograss to enhance liquid repellence by use of a hierarchical texture. Liquid repellence of the substrates is measured by contact angles of …

Three-Dimensional Scaffolds Of Graphene, Carbon Nanotubes And Transition-Metal Oxides For Applications In Electronics, Sensors And Energy Storage, Gilbert N. Mbah

Department of Chemistry: Dissertations, Theses, and Student Research

Electronics, sensors and energy storage devices are the new waves behind economic development, security and communication¹. Engineering small sizes of electronic, sensors and energy storage devices is the hurdle limiting efficient, portable and vast applications of Nano-devices for economic, security and communication advancement². Silicon the major material used in transistors has approached its limit to fabricated Nano-devices³. The discovery of free standing, one atomic layer thick and two-dimensional graphene sheets with high conductivity, inert, high specific surface area, stable and high tensile strength material in 2004 has shown capabilities to replaced silicon in electronics, …

Structural Patterns At All Scales In A Nonmetallic Chiral Au_133(Sr)_52 Nanoparticle, Chenjie Zeng, Yuxiang Chen, Kristin Kirschbaum, Kannatassen Appavoo, Matthew Y. Sfeir, Rongchao Jin

Publications and Research

Structural ordering is widely present in molecules and materials. However, the organization of molecules on the curved surface of nanoparticles is still the least understood owing to the major limitations of the current surface characterization tools. By the merits of x-ray crystallography, we reveal the structural ordering at all scales in a super robust 133–gold atom nanoparticle protected by 52 thiolate ligands, which is manifested in self-assembled hierarchical patterns starting from the metal core to the interfacial –S–Au–S– ladder-like helical “stripes” and further to the “swirls” of carbon tails. These complex surface patterns have not been observed in the smaller …

Reconfigurable Solid-State Dye-Doped Polymer Ring Resonator Lasers, Hengky Chandrahalim, Xudong Fan

Faculty Publications

This paper presents wavelength configurable on-chip solid-state ring lasers fabricated by a single-mask standard lithography. The single- and coupled-ring resonator hosts were fabricated on a fused-silica wafer and filled with 3,3′-Diethyloxacarbocyanine iodide (CY3), Rhodamine 6G (R6G) and 3,3′-Diethylthiadicarbocyanine iodide (CY5)-doped polymer as the reconfigurable gain media. The recorded lasing threshold was ~220 nJ/mm² per pulse for the single-ring resonator laser with R6G, marking the lowest threshold shown by solid-state dye-doped polymer lasers fabricated with a standard lithography process on a chip. A single-mode lasing from a coupled-ring resonator system with the lasing threshold of ~360 nJ/mm² per pulse …

One-Pot Synthesis Of Anionic (Nitrogen) And Cationic (Sulfur) Codoped High-Temperature Stable, Visible Light Active, Anatase Photocatalysts, Suresh Pillai, Declan Mccormack, Steven Hinder, Pradeepan Periyat

Articles

No abstract provided.

One-Pot Synthesis Of Anionic (Nitrogen) And Cationic (Sulfur) Codoped High-Temperature Stable, Visible Light Active, Anatase Photocatalysts, Suresh Pillai, Declan Mccormack, Steven Hinder, Pradeepan Periyat

Articles

No abstract provided.

Influence Of Magnesium Nitrate On The Corrosion Performance Of Sol-Gel Coated Aa2024-T3 Aluminium Alloy, Rajath Varma, Brendan Duffy, John Cassidy

Articles

Traditional anti-corrosion technology has relied heavily on using reducible metal species, predominantly hexavalent chromium (Cr(VI)), for protecting reactive metal alloys such as aluminium which is extensively used in the aerospace sector. However, the impending changes in the use of Cr(VI) in Europe and the United States have forced aerospace manufacturers to examine alternative materials for protecting aluminium. One of the most promising alternatives being investigated are organosilane based sol-gels containing anticorrosion additives. In this work the anti-corrosion properties of magnesium (II) nitrate (Mg(NO3)2) as a inhibitor was investigated at different concentrations (0.1% - 1.0 wt %) in a methyltriethoxysilane (MTEOS) …