TY - JOUR T1 - Photoexcited Surface Frustrated Lewis Pairs for Heterogeneous Photocatalytic Co2 Reduction JF - Am. Chem. Soc. Y1 - 2016 A1 - Ghuman, K. K. A1 - Hoch, L. B. A1 - Szymanski, P. A1 - Loh, J. Y. A1 - Kherani, N. P. A1 - El-Sayed, M. A. A1 - Ozin, G. A. A1 - Singh, C. V. ER - TY - JOUR T1 - Energy-Transfer Efficiency in Eu-Doped ZnO Thin Films: The Effects of Oxidative Annealing on the Dynamics and the Intermediate Defect States JF - Acs Applied Materials & Interfaces Y1 - 2014 A1 - Ahmed, S. M. A1 - Szymanski, P. A1 - El-Nadi, L. M. A1 - El-Sayed, M. A. VL - 6 SN - 1944-8244 N1 - Ahmed, Samah M. Szymanski, Paul El-Nadi, Lotfia M. El-Sayed, Mostafa A. M3 - 10.1021/am404662k ER - TY - JOUR T1 - The Last Step in Converting the Surface Plasmonic Energy into Heat by Nanocages and Nanocubes on Substrates JF - Small Y1 - 2013 A1 - Szymanski, P. A1 - Mahmoud, M A A1 - El-Sayed, M. A. VL - 9 SN - 1613-6810 N1 - Szymanski, Paul Mahmoud, Mahmoud A. El-Sayed, Mostafa A. M3 - 10.1002/smll.201300233 ER - TY - JOUR T1 - Different Methods of Increasing the Mechanical Strength of Gold Nanocages JF - Journal of Physical Chemistry Letters Y1 - 2012 A1 - Mahmoud, M A A1 - Szymanski, P. A1 - El-Sayed, M. A. AB - Using the ultrafast coherent modulation of the surface plasmon band intensity with the totally symmetric lattice vibration of gold nanocages, we were able to determine and use their frequencies as a measure of the cage's mechanical stability. The presence of an inner "stiff" transition-metal nanoshell with a higher value of the elastic modulus is found to increase the frequency of the lattice vibration of the outer soft gold nanoshell. This could also explain the observed increase in both the gold lattice vibrational frequency as well as the lattice vibration relaxation time in the Au-Pt and Au-Pd double-shell nanocages. It is also found that when these nanoparticles are assembled into monolayers on quartz substrates by the Langmuir-Blodgett technique, the oscillation frequency of the gold shell with the transition metal having the largest elastic constant suffers the least change in its oscillation frequency as a result of its resistance to distortion as a result of binding to the substrate. VL - 3 SN - 1948-7185 N1 - Times Cited: 0Mahmoud, Mahmoud A. Szymanski, Paul El-Sayed, Mostafa A. M3 - 10.1021/jz301503z ER - TY - JOUR T1 - Some recent developments in photoelectrochemical water splitting using nanostructured TiO2: a short review JF - Theoretical Chemistry Accounts Y1 - 2012 A1 - Szymanski, P. A1 - El-Sayed, M. A. AB - Photoelectrochemical cells with TiO2 electrodes to convert sunlight and water into gaseous hydrogen and oxygen are a source of clean and renewable fuel. Despite their great potential, far-from-ideal performance and poor utilization of the solar spectrum have prevented them from becoming a widespread and practical technology. We review recent experimental work that uses dynamics measurements to study limitations of photoelectrochemical cells from a fundamental level and the use of TiO2 nanotube arrays as a superior alternative to TiO2 nanoparticles. Through a combination of nanoscale size control, doping, composite materials, and the incorporation of noble-metal nanoparticles, improved performance and light harvesting are demonstrated. VL - 131 SN - 1432-881X N1 - Times Cited: 0Szymanski, Paul El-Sayed, Mostafa A. M3 - 10.1007/s00214-012-1202-2 ER - TY - JOUR T1 - Tailoring Plasmonic and Electrostatic Field Effects To Maximize Solar Energy Conversion by Bacteriorhodopsin, the Other Natural Photosynthetic System JF - Nano Letters Y1 - 2011 A1 - Yen, C. W. A1 - Hayden, S. C. A1 - Dreaden, Erik A1 - Szymanski, P. A1 - El-Sayed, Mostafa A AB - We have explored the plasmonic field enhancement of current production from bacteriorhodopsin (bR) by maximizing the blue light effect, where the influx of blue photons absorbed by the long-lived M intermediate drastically shortens the time scale of the bR photocycle, leading to current enhancement. To this end, we used three approaches in our solution-based cell: proton selective Nafion membrane. (2) We maximized the plasmonic surface (1) We improved the charge carrier separation in solution through the use of a field effects by selecting the capping polymer with minimum surface field screening and best nanopartide stability. (3) We selected the plasmonic nanoparticle with the strongest plasmonic field whose surface plasmon resonance has the largest spectral overlap with the blue light absorbing M-intermediate. Theoretical models are used to explain experimental results, which show a 40 nm cuboidal nanoparticle capped with 55k PVP polymer to give the best photocurrent enhancement. Enhanced by this particle, bR in our Nafion membrane solution cell gave a photocurrent of 0.21 mu A/cm(3), which is 5000 times larger than the published results for thin film bR electrochemical cells even with an applied bias. Additional possible enhancements are proposed. VL - 11 SN - 1530-6984 N1 - Yen, Chun-Wan Hayden, Steven C. Dreaden, Erik C. Szymanski, Paul El-Sayed, Mostafa A. M3 - 10.1021/nl2018959 ER -