Ultrafast transient absorption spectroscopy of porphyrin-based NanoGUMBOS, silver-gold core-shell, and silicon nanoparticles

Abstract

Event Abstract Back to Event Ultrafast transient absorption spectroscopy of porphyrin-based NanoGUMBOS, silver-gold core-shell, and silicon nanoparticles Jeewan C. Ranasinghe1, Asela S. Dikkumbura1, Rami A. Khoury1, Isiah Warner1 and Louis Haber1* 1 Louisiana State University, United States Ultrafast transient absorption spectroscopy provides information about excited state dynamics including electron transfer, energy transfer, internal conversion, and intersystem crossing providing important information relevant in optoelectronics, photovoltaics, and molecular sensing applications. The excited-state spectroscopy and ultrafast dynamics of porphyrin and zinc porphyrin-based nanoGUMBOS are reported. NanoGUMBOS are nanoparticles derived from a group of uniform materials based on organic salts or solid phase equivalents of ionic liquids. Porphyrin and zinc porphyrin dyes in water exhibit long-lived excited states on the order of several nanoseconds due to intersystem crossing to triplet states. However, these porphyrin lifetimes are significantly faster when in the nanoGUMBOS environment due to electronic delocalization, energy transfer, and enhanced intersystem crossing. In another study, the ultrafast spectroscopy of silver and silver-gold core-shell colloidal nanoparticles are investigated as a function of pump excitation power and nanoparticle size. The excited-state lifetimes of these plasmonic nanoparticles and their corresponding plasmon spectra show pump power dependence of electron-phonon and phonon-phonon scattering lifetimes. Additionally, the synthesis and spectroscopic characterization of silicon nanoparticles (SiNPs) are reported. As-synthesized SiNPs are terminated with allyl amine to protect the surface against oxidation. Temperature and pH-dependent luminescence is studied to determine the underlying mechanics of the corresponding excited-state relaxation. The photoluminescence intensity is observed to decrease under increasing temperature, indicating the presence of thermally-activated nonradiative relaxations with both reversible and nonreversible components. Overall, the synthesis, characterization, and ultrafast spectroscopy of a wide variety of colloidal nanomaterials are studied for the development of potential optoelectronic and molecular sensing applications. Acknowledgements Generous financial support for this work was provided from Louisiana State University. We would like to acknowledge Ying Xiao for help with transmission electron microscopy. Keywords: transient absorption, Nanoparticles, NanoGUMBOS, Silicon, core-shell, Electron-phonon and electron-electron interactions Conference: National Organization for the Professional Advancement of Black Chemists and Chemical Engineers (NOBCChE) 45th Annual Conference , Orlando, Florida, United States, 17 Sep - 20 Sep, 2018. Presentation Type: Poster Presentation Topic: Physical Chemistry Citation: Ranasinghe JC, Dikkumbura AS, Khoury RA, Warner I and Haber L (2019). Ultrafast transient absorption spectroscopy of porphyrin-based NanoGUMBOS, silver-gold core-shell, and silicon nanoparticles. Front. Chem. Conference Abstract: National Organization for the Professional Advancement of Black Chemists and Chemical Engineers (NOBCChE) 45th Annual Conference . doi: 10.3389/conf.fchem.2018.01.00015 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 09 Oct 2018; Published Online: 17 Jan 2019. * Correspondence: Mr. Louis Haber, Louisiana State University, Baton Rouge, United States, lhaber@lsu.edu Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Jeewan C Ranasinghe Asela S Dikkumbura Rami A Khoury Isiah Warner Louis Haber Google Jeewan C Ranasinghe Asela S Dikkumbura Rami A Khoury Isiah Warner Louis Haber Google Scholar Jeewan C Ranasinghe Asela S Dikkumbura Rami A Khoury Isiah Warner Louis Haber PubMed Jeewan C Ranasinghe Asela S Dikkumbura Rami A Khoury Isiah Warner Louis Haber Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.