A5060572309- Spectroscopy and Chemometric Analyses
- Thin-Film Transistor Technologies
- Spectroscopy Techniques in Biomedical and Chemical Research
- Photonic and Optical Devices
- Quantum Dots Synthesis And Properties
- Aquatic Ecosystems and Phytoplankton Dynamics
- Semiconductor Lasers and Optical Devices
- Conducting polymers and applications
- Advanced Fluorescence Microscopy Techniques
- Organic Electronics and Photovoltaics
- Analytical Chemistry and Sensors
- Nanowire Synthesis and Applications
- Gold and Silver Nanoparticles Synthesis and Applications
- Electronic and Structural Properties of Oxides
- Surfactants and Colloidal Systems
- Analytical chemistry methods development
- Catalytic Processes in Materials Science
- Marine Toxins and Detection Methods
- Silicon Nanostructures and Photoluminescence
- Marine and environmental studies
- Advanced Fiber Optic Sensors
- ZnO doping and properties
- Nonlinear Optical Materials Studies
- Plasmonic and Surface Plasmon Research
- Pesticide Residue Analysis and Safety
Iowa State University
2014-2020
Baylor University
2019-2020
Ames National Laboratory
2014-2017
United States Department of Energy
2014
The University of Texas at Arlington
2012
Cyanobacteria can form dense blooms under specific environmental conditions, and some species produce secondary metabolites known as cyanotoxins, which present significant risks to public health the environment. Identifying toxins produced by cyanobacteria in surface water fish is critical ensuring high quality food for consumption, protectionn of recreational uses. Current analytical screening methods typically focus on one class cyanotoxins a single matrix rarely include saxitoxin. Thus,...
Removing organics from hybrid nanostructures is a crucial step in many bottom-up materials fabrication approaches. It usually assumed that calcination an effective solution to this problem, especially for thin films. This assumption has led its application thousands of papers. We here show general incorrect by using relevant and highly controlled model system consisting films ligand-capped ZrO
Helium plasmas are attractive reagents for the removal of organics from hybrid materials because their minimal ablative power and relative inertness, compared to oxidizing feed gases such as O2 highly inert Ar. This work describes use dilute helium selectively remove organic ligands films colloidal nanoparticles (i.e., nanoparticle assemblies). We determine contribution etching different plasma species in a model system consisting ZrO2 capped with trioctylphosphine oxide. Unexpectedly, we...
We here describe a bottom-up approach to control the composition of solid/solid interfaces in nanostructured materials, and we test its effectiveness on tetragonal ZrO2, an inorganic phase great technological significance. Colloidal nanocrystals capped with trioctylphosphine oxide (TOPO) or oleic acid (OA) are deposited, organic fraction ligands is selectively etched O2 plasma. The resulting all-inorganic colloidal nanocrystal assemblies either nearly bare (for OA-capped nanocrystals)...
Polar organic chemical integrative sampler (POCIS) is a passive sampling device that offers many advantages over traditional discrete methods, but quantitative time-weighted average (TWA) concentrations rely heavily on the robustness of rates. The effects changing concentration exposures POCIS rates and its ability to operate in an regime were investigated for 12 pesticides across range environmentally relevant concentrations. In five independent 21-day experiments, devices exposed these...
Directional-surface-plasmon-coupled Raman scattering (directional RS) has the combined benefits of surface plasmon resonance and spectroscopy, provides ability to measure adsorption monolayer-sensitive chemical information. Directional RS is performed by optically coupling a 50 nm gold film Weierstrass prism in Kretschmann configuration scanning angle incident laser under total internal reflection. The collected parameters on side interface include full surface-plasmon-polariton cone signal...
Abstract There is an increasing demand for nondestructive in situ techniques that measure chemical content, total thickness, and interface locations multilayer polymer films, scanning angle (SA) Raman spectroscopy combination with appropriate data models can provide this information. A SA method was developed to the composition of waveguide films extract location buried interfaces between layers 7‐ 80‐nm axial spatial resolution. The acquires spectra as incident light upon a prism‐coupled...
This paper describes a simple approach to the large-scale synthesis of colloidal Si nanocrystals and their processing into spin-on carbon-free nanocrystalline films. The synthesized silicon nanoparticles are capped with decene, dispersed in hexane, deposited on substrates. films exposed nonoxidizing room-temperature He plasma remove organic ligands without adversely affecting form crack-free thin We further show that reactive ion etching rate these is 1.87 times faster than for...
The photostability of bulk heterojunction organic photovoltaic films containing a polymer donor and fullerene-derivative acceptor was examined using resonance Raman spectroscopy controlled laser power densities. donors were poly(3-hexylthiophene-2,5-diyl) (P3HT), poly[[9-(1-octylnonyl)-9H-carbazole-2,7-diyl]-2,5-thiophenediyl-2,1,3-benzothiadiazole-4,7-diyl-2,5-thiophenediyl] (PCDTBT), or...
Fourier transform (FT)-plasmon waveguide resonance (PWR) spectroscopy measures light reflectivity at a interface as the incident frequency and angle are scanned. Under conditions of total internal reflection, reflected intensity is attenuated when satisfy for exciting surface plasmon modes in metal well guided within waveguide. Expanding upon concept two-frequency developed by Peterlinz Georgiadis [Opt. Commun. 1996, 130, 260], apparent index refraction thickness can be measured precisely...
P3HT (poly (3-hexylthiophene)) has been widely used as a donor in the active layer organic photovoltaic devices. Although moderately high-power conversion efficiencies have achieved with P3HT-based devices, structural details, such orientation of polymer units and extent H- J-aggregation are not yet fully understood; different measures taken to control ordering material. One measure, which exploited, is apply an electric field from Van de Graaff generator. Fluorescence (to measure anisotropy...