@article{chagnot_abello_wang_dawlaty_rodriguez-lopez_zhang_augustyn_2024, title={Influence of Finite Diffusion on Cation Insertion-Coupled Electron Transfer Kinetics in Thin Film Electrodes}, volume={171}, ISSN={["1945-7111"]}, DOI={10.1149/1945-7111/ad1d98}, abstractNote={Materials that undergo ion-insertion coupled electron transfer are important for energy storage, energy conversion, and optoelectronics applications. Cyclic voltammetry is a powerful technique to understand electrochemical kinetics. However, the interpretation of the kinetic behavior of ion insertion electrodes with analytical solutions developed for ion blocking electrodes has led to confusion about their rate-limiting behavior. The purpose of this manuscript is to demonstrate that the cyclic voltammetry response of thin film electrode materials undergoing solid-solution ion insertion without significant Ohmic polarization can be explained by well-established models for finite diffusion. To do this, we utilize an experimental and simulation approach to understand the kinetics of Li+ insertion-coupled electron transfer into a thin film material (Nb2O5). We demonstrate general trends for the peak current vs scan rate behavior, with the latter parameter elevated to an exponent between limiting values of 1 and 0.5, depending on the solid-state diffusion characteristics of the film (diffusion coefficient, film thickness) and the experiment timescale (scan rate). We also show that values < 0.5 are possible depending on the cathodic potential limit. Our results will be useful to fundamentally understand and guide the selection and design of intercalation materials for multiple applications.}, number={1}, journal={JOURNAL OF THE ELECTROCHEMICAL SOCIETY}, author={Chagnot, Matthew and Abello, Sofia and Wang, Ruocun and Dawlaty, Jahan and Rodriguez-Lopez, Joaquin and Zhang, Chao and Augustyn, Veronica}, year={2024}, month={Jan} } @article{dewey_jones_lucas_hall_sultana_abello_budhathoki-uprety_2023, title={Carbon Nanotubes for Optical Detection of Quaternary Ammonium Compounds in Complex Media}, volume={6}, ISSN={2574-0970 2574-0970}, url={http://dx.doi.org/10.1021/acsanm.3c02219}, DOI={10.1021/acsanm.3c02219}, abstractNote={Quaternary ammonium compounds (QACs) are widely used in disinfectants, cleaners, preservatives, cosmetics, and agriculture. Recently, QACs have been detected in the human bloodstream, breast milk, and neonatal mouse brain, which shows that these compounds can cross biological barriers. In vivo studies showed that chronic low-level exposure to QACs causes developmental, reproductive, and immune dysfunctions, whereas in vitro studies indicate that QACs can affect reproductive systems, disrupt cholesterol biosynthesis, increase inflammatory cytokines, and decrease mitochondrial functions. Effects of QACs on health are gradually emerging, amid increased use of QAC disinfectants during the COVID-19 pandemic. Analysis of biological fluids including blood, urine, sweat, and saliva can provide vital information in determining the biological effects of analytes. Biofluid analysis is convenient yet crucial because of non-invasive/or minimally invasive procedures that can be performed outside hospital settings. Interest in optical detection methods for biofluid analysis has been growing due to recent advances in detection technologies and availability of tunable materials to aid the technologies. Detection in the near-infrared (NIR) spectral range is advantageous over the visible range mainly due to minimal autofluorescence, light-scattering, and absorption from native biological molecules in the NIR range. Photoluminescent single-walled carbon nanotubes (SWCNTs) are promising candidates for the development of NIR optical probes and sensors due to their non-photobleaching NIR fluorescence, tunable surface chemistry, and high sensitivity. Herein, we report optical detection of QACs in protein-rich media and a model biofluid. We functionalized photoluminescent SWCNTs with bile salt derivatives that enabled the detection of QACs in artificial sweat and serum-protein-enriched media. The QAC detection was significant at nanomolar concentrations, which is within the threshold that can affect various physiological processes. Thus, nanotube-based optical detection could be well suited for the analysis of QACs in biological fluids.}, number={17}, journal={ACS Applied Nano Materials}, publisher={American Chemical Society (ACS)}, author={Dewey, Hannah M. and Jones, Jaron and Lucas, Sydney and Hall, Shelby and Sultana, Nigar and Abello, Sofia Mariapaz and Budhathoki-Uprety, Januka}, year={2023}, month={Aug}, pages={15530–15539} }