@article {1587,
	title = {Probing Structural Evolution and Charge Storage Mechanism of Nio2hx Electrode Materials Using in Operando Resonance Raman Spectroscopy},
	journal = { Advanced Science},
	year = {2016},
	author = {Chen, D. and Xiong, X. and Zhao, B. and Mahmoud, M A and El-Sayed, M. A. and Liu, M.}
}
@article {1385,
	title = {Properties of pi-Conjugated Fluorescence Polymer-Plasmonic Nanoparticles Hybrid Materials (vol 116, 13336, 2012)},
	journal = {Journal of Physical Chemistry C},
	volume = {117},
	number = {9},
	year = {2013},
	note = {Mahmoud, M. A. Poncheri, A. J. El-Sayed, M. A. Bryant, J. Bunz, U.},
	month = {Mar},
	pages = {4876-4876},
	isbn = {1932-7447},
	doi = {10.1021/jp4006197},
	author = {Mahmoud, M A and Poncheri, A. J. and El-Sayed, M. A. and Bryant, J. and Bunz, U.}
}
@article {1338,
	title = {Properties of pi-Conjugated Fluorescence Polymer-Plasmonic Nanoparticles Hybrid Materials},
	journal = {Journal of Physical Chemistry C},
	volume = {116},
	number = {24},
	year = {2012},
	note = {Times Cited: 1Mahmoud, M. A. Poncheri, A. J. El-Sayed, M. A.},
	month = {Jun},
	pages = {13336-13342},
	abstract = {Recently, great interest has risen in studying and using hybrid material made by mixing polymeric materials with plasmonic nanoparticles. In the present work, the photophysical properties of two poly(p-phenyleneethynylene) fluorescent polymers, varying in chain length, were studied as a function of (1) pure polymer surface compression after deposition from a Langmuir-Blodgett trough onto a substrate and (2) deposition of a constant amount of polymer onto the surface of silver nanocube arrays of varying particle densities. The results are discussed in terms of the surface pressure and nanoparticle topography effects on conformation of the fluorescent polymer. It was found that the short polymer is much less affected by increased surface pressure, remaining isolated from interchain interaction. The long polymer exhibits signs of conjugation breaking, presumably due to compression of its longer, "tangled", structure. The two polymer chains in the nanoparticle/polymer series of experiments exhibited a blue-shift and a substantial narrowing of their emission spectra when deposited onto the lowest surface pressure nanoparticle sample. With increasing nanoparticle density, the spectra continue to blue-shift and narrow. This effect is presumably a combined effect of conformational changes that shift the emission to higher energy (blue-shift) and plasmonic effects that result in enhancement of primary emission of the polymer (emission from the 0-0 and 1-0 transitions), thus narrowing the emission.},
	isbn = {1932-7447},
	doi = {10.1021/jp303908e},
	author = {Mahmoud, M A and Poncheri, A. J. and El-Sayed, M. A.}
}
@article {1077,
	title = {Plasmonic Field Effects on the Energy Transfer between Poly(p-phenyleneethynylene) Fluorescent Polymer and Au Nanocages},
	journal = {Journal of Physical Chemistry C},
	volume = {115},
	number = {26},
	year = {2011},
	note = {Mahmoud, M. A. El-Sayed, M. A.},
	month = {Jul},
	pages = {12726-12735},
	abstract = {Colloidal gold nanocages (AuNCs) with a wall length of 60 nm and wall thickness of 6 nm were prepared by the galvanic replacement method. The AuNCs were assembled into monolayers with different percents of surface coverage, using the Langmuir-Blodgett technique. The same technique was used to coat the assembled monolayers of AuNCs with another monolayer of poly(p-phenyleneethynylene) (PPE) fluorescent polymer. The surface plasmon resonance (SPR) spectrum of the AuNCs red-shifts as the percent of AuNCs coverage increases due to growth of the interparticle surface plasmon resonance field coupling as interparticle distance decreases. While after coating the AuNCs array with PPE, the SPR of all the AuNCs monolayers arrays were red-shifted to the same position (693 nm). This unsystematic red-shift behavior is based on the presence of two plasmon fields (inside and outside of AuNCs) and is described by discrete dipole approximation (DDA) simulation. The polymer fluorescence intensity is found to decrease when the polymer is deposited over the AuNCs. This observation is due to the energy transfer between the excited PPE and the AuNCs as well interchain energy transfer. Upon turning on the plasmonic field (exciting the surface plasmon resonance band), it is found that the fluorescence intensity of the polymer increased to a maximum value at AuNCs percent coverage of 10\% and then decreased as the interparticle separation distance decreased. DDA calculations showed that this is consistent with the dependence of the SPR field strength on the interparticle separation. Physically, this is a result of the interplay between the changes in the surface plasmon fields within the cavity of each nanoparticle and their external surface fields as a pair of AuNCs approach one another.},
	isbn = {1932-7447},
	doi = {10.1021/jp2007528},
	author = {Mahmoud, M A and El-Sayed, Mostafa A}
}
@article {1093,
	title = {Plasmonic Field Enhancement of the Exciton-Exciton Annihilation Process in a Poly(p-phenyleneethynylene) Fluorescent Polymer by Ag Nanocubes},
	journal = {Journal of the American Chemical Society},
	volume = {132},
	number = {8},
	year = {2010},
	note = {Mahmoud, Mahmoud A. Poncheri, Adam J. Phillips, Ronnie L. El-Sayed, Mostafa A.},
	month = {Mar},
	pages = {2633-2641},
	abstract = {Using the Langmuir-Blodgett (LB) technique, a poly(paraphenyleneethynylene) (PPE) fluorescent conjugated polymer was assembled on either a quartz substrate (system I) or on the surface of silver nanocube (AgNC) monolayers (system II). The fluorescence intensity of the polymer was studied in system I as a function of the surface density of the polymer sample when deposited on quartz substrates and in system II on the surface coverage of the underlying AgNC monolayers. In system I, a continual increase in the fluorescence intensity is observed as the surface density of excited polymer is increased. In system II, the fluorescence intensity of the polymer first increased until a threshold surface coverage of AgNC was reached, after which it decreased rapidly with increasing surface coverage in the AgNC monolayer. The exciting light intensity dependence is studied before and after this threshold in system II. The results suggest that one-photon processes were responsible for the increased intensity before the threshold, and two-photon processes were responsible for the rapid decrease in the polymer fluorescence intensity after the threshold. These observations are explained by the increase of the surface plasmon enhancement of the exciting light intensity as the nanoparticle surface coverage is increased. In turn, this increases the polymer absorption rate, which results in a continuous increase in the exciton density and is evident by an increase in the fluorescence intensity. At the threshold, the increased exciton density leads to an increase in the rate of exciton-exciton collisions, which leads to exciton-exciton annihilations. When this phenomenon becomes faster than the rate of fluorescence emission, an intensity decrease is observed. By exploiting the surface plasmon enhancement of absorption processes, we have observed the first exciton-exciton annihilation using a low-intensity Hg-lamp continuous wave source.},
	isbn = {0002-7863},
	doi = {10.1021/ja907657j},
	author = {Mahmoud, M A and Poncheri, A. J. and Phillips, R. L. and El-Sayed, Mostafa A}
}
@article {1091,
	title = {Polystyrene Microspheres: Inactive Supporting Material for Recycling and Recovering Colloidal Nanocatalysts in Solution},
	journal = {Journal of Physical Chemistry Letters},
	volume = {1},
	number = {1},
	year = {2010},
	note = {Mahmoud, M. A. Snyder, B. El-Sayed, M. A.},
	month = {Jan},
	pages = {28-31},
	abstract = {Alumina and silica have been the most commonly, used solid supports in the recovery of colloidal nanocatalysts in solution. In order to avoid possible involvement of the support in the catalytic mechanism, polystyrene microspheres are here demonstrated to be effective and nonreactive supports on which the nanocatalyst can be easily attached by using the swelling and shrinking properties of the polystyrene microspheres. The activation energy of the reduction of 4-nitrophenol with sodium borohydride on platinum nanocubes free in solution is comparable to those on polystyrene microspheres.},
	isbn = {1948-7185},
	doi = {10.1021/jz9000449},
	author = {Mahmoud, M A and Snyder, B. and El-Sayed, Mostafa A}
}
@article {1107,
	title = {Photocatalysis in Gold Nanocage Nanoreactors},
	journal = {Journal of Physical Chemistry A},
	volume = {113},
	number = {16},
	year = {2009},
	note = {Yen, C. W. Mahmoud, M. A. El-Sayed, M. A.},
	month = {Apr},
	pages = {4340-4345},
	abstract = {The photodegradation of methyl orange was found to take place very efficiently using hollow Au nanocages which are known to have remaining Ag on their interior walls which can be oxidized to Ag(2)O. The degradation rate is found to be more efficient than photodegradation reaction using semiconductor nanomaterials, such as TiO(2) and ZnO. The reaction rate is found to increase by increasing the degree of Ag oxidation on the interior wall of the nanocages prior to the reaction and is a function of the nanocavity size and the pore density of the nanocage walls. As the cage size varies, it is found that the photocatalytic rate increases and then decreases with a maximum rate at nanoparticle size of 75 nm with a medium pore density-in the walls. All these results suggest that the catalysis is occurring inside the cavity, whose interior walls are covered with the Ag(2)O catalysts. Similar to the mechanism proposed in the degradation by the other semiconductors, we propose that the photodegradation mechanism involves the formation of the hydroxyl radical resulting from the photoexcitation of the Ag(2)O semiconductor. The observed results on the rate are discussion in terms of (1) the surface area of the inner wall covered with Ag (Ag(2)O), (2) the density and size of the pores in the walls, and (3) the cavity size of the nanoparticles.},
	isbn = {1089-5639},
	doi = {10.1021/jp811014u},
	author = {Yen, C. W. and Mahmoud, M A and El-Sayed, Mostafa A}
}
