@article {1658,
	title = {Observation of Photoinduced Proton Transfer between the Titania Surface and Dye Molecule},
	journal = {The Journal of Physical Chemistry C},
	year = {2020},
	author = {Nishikiori, H. and Kondo, H. and Kageshima, Y. and Hooshmand, N. and Panikkanvalappil, S. R. and Valverde-Ch{\'a}vez, D.A. and Silva, C. and El-Sayed, M.A. and Teshima,K.}
}
@article {1659,
	title = {Plasmonic and chiroplasmonic nanobiosensors based on gold nanoparticles},
	journal = {Talanta},
	year = {2020},
	author = {Sharifi, M. and Hosseinali, S.H. and Alizadeh, R.H. and Hasan, A. and Attar, F. and Salihi, A. and Shekha, M.S. and Amen, K.M. and Aziz, F.M. and Saboury, A.A. and Akhtari, K. and Taghizadeh, A. and Hooshmand, N. and El-Sayed, M. A. and Falahati, M.}
}
@article {1656,
	title = {Enhanced Electrochemical Dark-Field Scattering Modulation on Single Hybrid Core-Shell Nanostructure},
	journal = {The Journal of Physical Chemistry C},
	year = {2019},
	author = {Zhou, J. and Panikkanvalappil, S.R. and Kang, S. and Yu, S. and Zhang, S. and El-Sayed, M.A. and Tsukruk, V.V.}
}
@article {1652,
	title = {Enhancing Plasmonic{\textendash}Photonic Hybrid Cavity Modes by Coupling of Individual Plasmonic Nanoparticles},
	journal = {The Journal of Physical Chemistry C},
	year = {2019},
	author = {Zhang, S. and Panikkanvalappil, S.R. and Kang, S. and Smith, M.J. and Yu, S. and El-Sayed, M. and Tsukruk, V.V.}
}
@article {1636,
	title = {Dual-excitation nanocellulose-plasmonic membranes for molecular and cellular SERS detection},
	journal = {ACS applied materials \& interfaces},
	year = {2018},
	author = {S. Zhang and R. Xiong and Mahmoud, M A and E. Quigley and H. Chang and El-Sayed, M. A. and Tsukruk, V. V.}
}
@article {1639,
	title = {Gold Nanorod-Photothermal Therapy Alters Cell Junctions and Actin Network in Inhibiting Cancer Cell Collective Migration},
	journal = {ACS nano},
	year = {2018},
	author = {Y. Wu and Ali, M. R. K. and B. Dong and T. Han and K. Chen and J. Chen and Y. Tang and N. Fang and F. Wang and El-Sayed, M. A.}
}
@article {1593,
	title = { Electrically Controlled Plasmonic Behavior of Gold Nanocube@ Polyaniline Nanostructures: Transparent Plasmonic Aggregates},
	journal = {Chem. Mater.},
	year = {2016},
	author = {Jeon, J.-W. and Ledin, P. A. and Geldmeier, J. A. and Ponder, J. F. and Mahmoud, M A and El-Sayed, M. and Reynolds, J. R. and Tsukruk, V. V.}
}
@article {1575,
	title = {Light-responsive plasmonic arrays consisting of silver nanocubes and a photoisomerizable matrix.},
	journal = {ACS Appl Mater Interfaces},
	volume = {7},
	year = {2015},
	month = {2015 Mar 4},
	pages = {4902-12},
	abstract = {We report on the synthesis of novel branched organic-inorganic azo-polyhedral oligomeric silsesquioxane (POSS) conjugates (Azo-POSS) and their use as a stable active medium to induce reversible plasmonic modulations of embedded metal nanostructures. A dense monolayer of silver nanocubes was deposited on a quartz substrate using the Langmuir-Blodgett technique and subsequently coated with an ultrathin Azo-POSS layer. The reversible light-induced photoisomerization between the trans and cis states of the azobenzene-terminated branched POSS material results in significant changes in the refractive index (up to 0.17) at a wavelength of 380 nm. We observed that the pronounced and reversible change in the surrounding refractive index results in a corresponding hypsochromic plasmonic shift of 6 nm in the plasmonic band of the embedded silver nanocubes. The reversible tuning of the plasmonic modes of noble-metal nanostructures using a variable-refractive-index medium opens up the possibility of fabricating photoactive, hybrid, ultrathin coatings with robust, real-time, photoinitiated responses for prospective applications in photoactive materials that can be reversibly tuned by light illumination.},
	issn = {1944-8252},
	doi = {10.1021/am508993z},
	author = {Ledin, Petr A and Russell, Michael and Geldmeier, Jeffrey A and Tkachenko, Ihor M and Mahmoud, Mahmoud A. and Shevchenko, Valery and El-Sayed, Mostafa A. and Tsukruk, Vladimir V.}
}
@article {1576,
	title = {Silver nanocube aggregation gradient materials in search for total internal reflection with high phase sensitivity},
	journal = {Nanoscale},
	volume = {7},
	year = {2015},
	pages = {5230-5239},
	abstract = {We fabricated monolayer coatings of a silver nanocube aggregation to create a step-wise optical strip by applying different surface pressures during slow Langmuir-Blodgett deposition. The varying amount of randomly distributed nanocube aggregates with different surface coverages in gradient manner due to changes in surface pressure allows for continuous control of the polarization sensitive absorption of the incoming light over a broad optical spectrum. Optical characterization under total internal reflection conditions combined with electromagnetic simulations reveal that the broadband light absorption depends on the relative orientation of the nanoparticles to the polarization of the incoming light. By using computer simulations, we found that the electric field vector of the s-polarized light interacts with the different types of silver nanocube aggregations to excite different plasmonic resonances. The s-polarization shows dramatic changes of the plasmonic resonances at different angles of incidence (shift of 64 nm per 10[degree] angle of incidence). With a low surface nanocube coverage (from 5\% to 20\%), we observed a polarization-selective high absorption of 80\% (with an average 75\%) of the incoming light over a broad optical range in the visible region from 400 nm to 700 nm. This large-area gradient material with location-dependent optical properties can be of particular interest for broadband light absorption, phase-sensitive sensors, and imaging.},
	doi = {10.1039/C4NR06430E},
	url = {http://dx.doi.org/10.1039/C4NR06430E},
	author = {Konig, Tobias A. F. and Ledin, Petr A and Russell, Michael and Geldmeier, Jeffrey A and Mahmoud, Mahmoud. A. and El-Sayed, Mostafa A. and Tsukruk, Vladimir V.}
}
@article {1363,
	title = {Electrically Tunable Plasmonic Behavior of Nanocube-Polymer Nanomaterials Induced by a Redox Active Electrochromic Polymer},
	journal = {ACS nano},
	year = {2014},
	isbn = {1936-0851},
	author = {K{\"o}nig, Tobias AF and Ledin, Petr A and Kerszulis, Justin and Mahmoud, Mahmoud A. and El-Sayed, Mostafa A. and Reynolds, John R and Tsukruk, Vladimir V.}
}
@article {1364,
	title = {Silver Nanocube Aggregates in Cylindrical Pores for Higher Refractive Index Plasmonic Sensing},
	journal = {Particle \& Particle Systems Characterization},
	volume = {31},
	number = {2},
	year = {2014},
	pages = {274-283},
	isbn = {1521-4117},
	author = {K{\"o}nig, Tobias and Kodiyath, Rajesh and Combs, Zachary A. and Mahmoud, Mahmoud and El-Sayed, Mostafa A and Tsukruk, Vladimir V.}
}
@article {1357,
	title = {Stacked Gold Nanorectangles with Higher Order Plasmonic Modes and Top-Down Plasmonic Coupling},
	journal = {The Journal of Physical Chemistry C},
	volume = {118},
	number = {10},
	year = {2014},
	pages = {5453-5462},
	isbn = {1932-7447},
	author = {Malak, Sidney T. and König, Tobias and Near, Rachel and Combs, Zachary A. and El-Sayed, Mostafa A. and Tsukruk, Vladimir V.}
}
@article {1399,
	title = {Aptamer-Assisted Assembly of Gold Nanoframe Dimers},
	journal = {Particle \& Particle Systems Characterization},
	volume = {30},
	number = {12},
	year = {2013},
	pages = {1071-1078},
	isbn = {1521-4117},
	author = {Combs, Zachary A. and Malak, Sidney T. and K{\"o}nig, Tobias and Mahmoud, Mahmoud A. and Ch{\'a}vez, Jorge L and El-Sayed, Mostafa A and Kelley-Loughnane, Nancy and Tsukruk, Vladimir V.}
}
@article {1349,
	title = {Assemblies of silver nanocubes for highly sensitive SERS chemical vapor detection},
	journal = {J. Mater. Chem. A},
	volume = {1},
	number = {8},
	year = {2013},
	note = {CAPLUS AN 2013:172950(Journal; Online Computer File)},
	month = {//},
	pages = {2777-2788},
	publisher = {Royal Society of Chemistry},
	type = {10.1039/c2ta00867j},
	abstract = {Probably Ag nanocube (AgNC) aggregates within cylindrical pores (PAM-AgNC) can be employed as efficient nanostructures for highly efficient, robust, tunable, and reusable surface-enhanced Raman scattering (SERS) substrates for trace level org. vapor detection which is a challenging task in chem. detection. The authors demonstrate the ability to tune both the detection limit and the onset of signal satn. of the substrate by switching the adsorption behavior of AgNCs between highly aggregated and more disperse by varying the no. of adsorption-mediating polyelectrolyte bilayers on the pore walls of the membrane. The different AgNC distributions show large differences in the trace vapor detection limit of the common Raman marker benzenethiol (BT) and a widely used explosive binder N-Me-4-nitroaniline (MNA), demonstrating the importance of the large electromagnetic field enhancement assocd. with AgNC coupling. The SERS substrate with highly aggregated AgNCs within the cylindrical pores allows for consistent trace detection of mid ppb (\~{}500) for BT analyte, and a record limit of detection of low ppb (\~{}3) for MNA vapors with an estd. achievable limit of detection of \~{}600 ppt. The dispersed AgNC aggregates do not sat. at higher ppb concns., providing an avenue to distinguish between higher ppb concns. and increase the effective range of the SERS substrate design. A comparison between the AgNC substrate and an electroless deposition substrate with Ag quasi-nanospheres (PAM-AgNS) also demonstrates a higher SERS activity, and better detection limit, by the nanocube aggregates. This is supported by FDTD electromagnetic simulations that suggest that the higher integrated electromagnetic field intensity of the hot spots and the large specific interfacial areas impart greatly improved SERS for the AgNCs. Also, the AgNC substrate can be reused multiple times without significant loss of SERS activity which opens up new avenues for in-field monitoring. [on SciFinder(R)]},
	keywords = {polymer electrolyte film silver nanocube nanosphere SERS sensor explosive, porous alumina silver nanoparticle SERS substrate explosive, silver nanocube nanosphere SERS sensor benzenethiol methyl nitroaniline polyelectrolyte, vapor sensor silver nanoparticle SERS substrate},
	isbn = {2050-7496},
	doi = {10.1039/c2ta00867j},
	author = {Kodiyath, Rajesh and Malak, Sidney T. and Combs, Zachary A. and Koenig, Tobias and Mahmoud, Mahmoud A. and El-Sayed, Mostafa A. and Tsukruk, Vladimir V.}
}
@article {1380,
	title = {Rapid and Efficient Prediction of Optical Extinction Coefficients for Gold Nanospheres and Gold Nanorods},
	journal = {Journal of Physical Chemistry C},
	volume = {117},
	number = {45},
	year = {2013},
	note = {Near, Rachel D. Hayden, Steven C. Hunter, Ronald E., Jr. Thackston, Daniel El-Sayed, Mostafa A.},
	month = {Nov},
	pages = {23950-23955},
	isbn = {1932-7447},
	doi = {10.1021/jp4082596},
	author = {Near, R. D. and Hayden, S. C. and Hunter, R. E. and Thackston, D. and El-Sayed, M. A.}
}
@article {1348,
	title = {Surface Assembly and Plasmonic Properties in Strongly Coupled Segmented Gold Nanorods},
	journal = {Small},
	year = {2013},
	note = {MEDLINE AN 2013463112(Journal; Article; (JOURNAL ARTICLE))},
	month = {//},
	abstract = {An assembly strategy is reported such that segmented nanorods fabricated through template-assisted methods can be robustly transferred and tethered to a pre-functionalized substrate with excellent uniformity over large surface areas. After embedding the rods, sacrificial nickel segments were selectively etched leaving behind strongly coupled segmented gold nanorods with gaps between rods below 40 nm and as small as 2 nm. Hyper-spectral imaging is utilized to measure Rayleigh scattering spectra from individual and coupled nanorod elements in contrast to common bulk measurements. This approach discerns the effects of not only changing segment and gap size but also the presence of characteristic defects on the plasmonic coupling between closely spaced nanorods. Polarized hyper-spectral measurements are conducted to provide direct observation of the anisotropic plasmonic resonance modes in individual and coupled nanorods, which are close to those predicted by computer simulations for nanorods with ideal shapes. Some common deviations from ideal shape such as non-flat facets and asymmetric tails are demonstrated to result in the appearance of characteristic plasmon resonances, which have not been considered before. The large-scale assembly of coupled noble nanostructures with fine control over geometry and high uniformity provides means to strongly tune the scattering, absorption, and near-field plasmonic properties through the geometric arrangement of precisely controlled nanorod segments.[on SciFinder (R)]},
	isbn = {1613-6829},
	author = {Gupta, Maneesh K. and Konig, Tobias and Near, Rachel and Nepal, Dhriti and Drummy, Lawrence F. and Biswas, Sushmita and Naik, Swati and Vaia, Richard A. and El-Sayed, Mostafa A. and Tsukruk, Vladimir V.}
}
@article {1342,
	title = {Pronounced Effects of Anisotropy on Plasmonic Properties of Nanorings Fabricated by Electron Beam Lithography},
	journal = {Nano Letters},
	volume = {12},
	number = {4},
	year = {2012},
	note = {Times Cited: 3Near, Rachel Tabor, Christopher Duan, Jinsong Pachter, Ruth El-Sayed, Mostafa},
	month = {Apr},
	pages = {2158-2164},
	abstract = {Gold nanoring dimers were fabricated via EBL with dimensions of 127.6 +/- 2.5 and 57.8 +/- 2.3 nm for the outer and inner diameters, respectively, with interparticle separations ranging from 17.8 +/- 3.4 to 239.2 +/- 3.7 nm. The coupling between the inner and outer surfaces of a single nanoring renders it very sensitive to any anisotropy. We found that anisotropy in the particle geometry and anisotropy introduced by the substrate combine to create very unique spectral features in this system.},
	isbn = {1530-6984},
	doi = {10.1021/nl300622p},
	author = {Near, R. and Tabor, C. and Duan, J. S. and Pachter, R. and El-Sayed, M.}
}
@article {1334,
	title = {The unusual fluorescence intensity enhancement of poly(p-phenyleneethynylene) polymer separated from the silver nanocube surface by H-bonded LbL shells},
	journal = {Journal of Materials Chemistry},
	volume = {22},
	number = {33},
	year = {2012},
	note = {Times Cited: 0Lisunova, Milana Mahmoud, Mahmoud Holland, Neal Combs, Zachary A. El-Sayed, Mostafa A. Tsukruk, Vladimir V.},
	pages = {16745-16753},
	abstract = {The fluorescence intensity of poly(p-phenyleneethynylene) (PPE) polymer separated from the surface of plasmonic silver nanocubes (47 nm AgNCs) is measured by varying the number of layers of polyvinyl pyrrolidone (PVPON) and polymethyl acrylic acid (PMAA), n. The shell thickness is sensitive to the solvent due to the formation of a solvent-sensitive hydrogen bonding network. The fluorescent behavior of the PPE on the core-shell PPE-(PVPON-PMAA) n-AgNCs structures fabricated here was evaluated as a function of n as well as the nature of the surrounding solvent. Surprisingly, the fluorescence intensity of the outer PPE shell is found to increase dramatically (by more than an order of magnitude) as its separation from the nanoparticle surface increases and then decreases at a distance that depends upon the swelling behavior of the polymer shells. The distance for the highest fluorescence enhancement was found to be 20.0 nm and 24.0 nm, in water and ethanol respectively. The observed change in the fluorescence intensity of the PPE polymer with increasing its separation from the plasmonic surface is proposed to result from the interplay between a short range quenching mechanism and a relatively long-range plasmonic fluorescence enhancing mechanism. DDA calculations gave support to the significant contribution of the latter mechanism.},
	isbn = {0959-9428},
	doi = {10.1039/c2jm32450d},
	author = {Lisunova, M. and Mahmoud, M. and Holland, N. and Combs, Z. A. and El-Sayed, M. A. and Tsukruk, V. V.}
}
@article {1075,
	title = {Influence of Steam Treatment on Dye-Titania Complex Formation and Photoelectric Conversion Property of Dye-Doped Titania Gel},
	journal = {Journal of Physical Chemistry C},
	volume = {115},
	number = {6},
	year = {2011},
	note = {Nishikiori, Hiromasa Uesugi, Yohei Takami, Shohei Setiawan, RudiAgus Fujii, Tsuneo Qian, Wei El-Sayed, Mostafa A.},
	month = {Feb},
	pages = {2880-2887},
	abstract = {Xanthene dye molecules form a chelate complex with the titanium species on the titania surface in dye-titania systems. The complex formation causes a fast electron injection into the titania conduction band. In this study, simple spectroscopic and photocurrent measurements of the xanthene dye-doped titania gels prepared by the sol-gel method were conducted in order to clarify the influence of a steam treatment on the dye-titania interaction and electron transfer. The photocurrent quantum efficiency of the fluorescein-doped electrode was remarkably increased by the steam treatment compared to that of the untreated electrode consisting of an amorphous titania gel. The photocurrent action spectrum was red-shifted, and the short circuit photocurrent and open circuit voltage values increased with the steam treatment time. The steam treatment promoted the dye-titania complex formation, a negative shift in the conduction band potential of the titania, and the electron injection from the dye to the titania.},
	isbn = {1932-7447},
	doi = {10.1021/jp109958z},
	author = {Nishikiori, H. and Uesugi, Y. and Takami, S. and Setiawan, R. and Fujii, T. and Qian, Wei and El-Sayed, Mostafa A}
}
@article {1084,
	title = {Multimodal plasmon coupling in low symmetry gold nanoparticle pairs detected in surface-enhanced Raman scattering},
	journal = {Applied Physics Letters},
	volume = {98},
	number = {18},
	year = {2011},
	note = {Dreaden, Erik C. Near, Rachel D. Abdallah, Tamer Talaat, M. Hassan El-Sayed, Mostafa A.},
	month = {May},
	abstract = {We report on surface-enhanced Raman scattering of silicon phonon vibrations from arrays of gold nanoprism pairs fabricated by electron beam lithography. We found that resonant excitation of the quadrupolar surface plasmon mode of the nanoprisms increases Raman scattering intensity from the substrate as the distance between the nanoparticle pairs decreases. Finite element modeling and plasmon coupling theory indicate that symmetry is reduced as the nanoparticles approach, resulting in increased dipole-quadrupole coupling. Plasmonic enhancement of the incident and Raman-scattered photons results from the dipolar component of the mixed plasmonic field. This effect is expected to be largest in assemblies/aggregates of nanoparticles. (C) 2011 American Institute of Physics. [doi:10.1063/1.3555429]},
	isbn = {0003-6951},
	doi = {10.1063/1.3555429},
	author = {Dreaden, Erik and Near, R. D. and Abdallah, T. and Talaat, M. H. and El-Sayed, Mostafa A}
}
@article {1111,
	title = {Effect of Orientation on Plasmonic Coupling between Gold Nanorods},
	journal = {Acs Nano},
	volume = {3},
	number = {11},
	year = {2009},
	note = {Tabor, Christopher Van Haute, Desiree El-Sayed, Mostafa A.},
	month = {Nov},
	pages = {3670-3678},
	abstract = {Radiative coupling of induced plasmonic fields in metal nanoparticles has drawn increasing attention in the recent literature due to a combination of improved experimental methods to study such phenomena and numerous potential applications, such as plasmonic nanoparticle rulers and plasmonic circuitry. Many groups, including ours, have used a near-exponential fit to express the size scaling of plasmonic coupling. First, we show experimental agreement between previously simulated nanorod coupling and plasmonic coupling in electron beam lithography (EBL) fabricated nanorods using the near-exponential expression. Next, we study the effect of nanoparticle orientation on plasmonic coupling using EBL and DDA simulations. We develop a mathematical relationship that is consistent with our findings and quantitatively describes plasmonic coupling between nanorods as a function of orientation, separation, induced dipole strength, and the dielectric constant of the medium. For applications utilizing plasmonic coupling to become viable with particle shapes that do not have spherical symmetry, such as nanoprisms and nanorods, comparison of the experimental and theoretical results of how particle orientation affects plasmonic coupling is essential.},
	isbn = {1936-0851},
	doi = {10.1021/nn900779f},
	author = {Tabor, C. E. and Van Haute, D. and El-Sayed, Mostafa A}
}
@article {1110,
	title = {The sensitivity of the energy band gap to changes in the dimensions of the CdSe quantum rods at room temperature: STM and theoretical studies},
	journal = {Chemical Physics Letters},
	volume = {473},
	number = {4-6},
	year = {2009},
	note = {Talaat, H. Abdallah, T. Mohamed, M. B. Negm, S. El-Sayed, Mostafa A.},
	month = {May},
	pages = {288-292},
	abstract = {The energy band gap of a series of different sizes of CdSe quantum rods have been determined by STM technique at room temperature. The results confirm that the band gap of CdSe quantum rods (QRs) depends mainly on the width (the dimension of the electron confinement) and only slightly on the length as shown previously in the literatures. The experimental data is compared to that calculated using two theoretical models, the effective mass approximation (EMA) and the semi-empirical pseudopotential method (SEPM). The theoretical values for the energy band gap at varying radius are in agreement with the experimental results within 0.08 eV. (c) 2008 Published by Elsevier B.V.},
	isbn = {0009-2614},
	doi = {10.1016/j.cplett.2008.11.025},
	author = {Talaat, M. H. and Abdallah, T. and Mohamed, MB and Negm, S. and El-Sayed, Mostafa A}
}
@article {1115,
	title = {Surface-Enhanced Raman Scattering Enhancement by Aggregated Silver Nanocube Monolayers Assembled by the Langmuir-Blodgett Technique at Different Surface Pressures},
	journal = {Journal of Physical Chemistry C},
	volume = {113},
	number = {14},
	year = {2009},
	note = {Mahmoud, M. A. Tabor, C. E. El-Sayed, M. A.},
	month = {Apr},
	pages = {5493-5501},
	abstract = {The surface-enhanced Raman scattering spectrum of poly(vinyl) pyrrolidone (PVP) molecules capping 50 nm silver nanocubes assembled in a monolayer via the Langmuir-Blodgett (LB) technique is studied at different surface pressures (at different nanoparticle densities). The observed correlation between the intensity of different SERS bands of the PVP with the nanoparticle density and those of the extinction intensity of the localized surface plasmon resonance bands (as a measure of the surface plasmon field) suggests the following: (1) the observed SERS enhancement results mostly from surface fields of the aggregated nanoparticles; and (2) the relative intensities of the different Raman bands are in reasonable agreement with those expected from the electromagnetic mechanism of enhancement. Besides the large surface plasmon field used in the Raman scattering enhancement, the broad SPR band of the aggregated nanocubes provides an additional advantage in the analytical applications of Raman spectroscopy.},
	isbn = {1932-7447},
	doi = {10.1021/jp900648r},
	author = {Mahmoud, M A and Tabor, C. E. and El-Sayed, Mostafa A}
}
@article {1112,
	title = {On the Use of Plasmonic Nanoparticle Pairs As a Plasmon Ruler: The Dependence of the Near-Field Dipole Plasmon Coupling on Nanoparticle Size and Shape},
	journal = {Journal of Physical Chemistry A},
	volume = {113},
	number = {10},
	year = {2009},
	note = {Tabor, Christopher Murali, Raghunath Mahmoud, Mahmoud El-Sayed, Mostafa A.},
	month = {Mar},
	pages = {1946-1953},
	abstract = {The localized surface plasmon resonance (LSPR) spectral band of a gold or silver nanoparticle is observed to shift as a result of the near-field plasmonic field of another nanoparticle. The dependence of the observed shift on the interparticle distance is used as a ruler in biological systems and gave rise to a plasmonic ruler equation in which the fractional shift in the dipole resonance is found to decrease near exponentially with the interparticle separation in units of the particle size. The exponential decay length constant was observed to be consistent among a small range of nanoparticle sizes, shapes, and types of metal. The equation was derived from the observed results on disks and spherical nanoparticles and confirmed using results on a DNA conjugated nanosphere system. The aim of the present paper is to use electron beam lithography and DDA calculations to examine the constancy of the exponential decay length value in the plasmonic ruler equation on particle size and shape of a number of particles including nanoparticles of different symmetry and orientations. The results suggest that the exponent is almost independent of the size of the nanoparticle but very sensitive to the shape. A discussion of the nanoparticles most suitable for different applications in biological systems and a comparison of the plasmonic ruler with Forster resonance energy transfer (FRET) is mentioned.},
	isbn = {1089-5639},
	doi = {10.1021/jp807904s},
	author = {Tabor, C. E. and Murali, R. and Mahmoud, M A and El-Sayed, Mostafa A}
}
@article {1120,
	title = {Can the observed changes in the size or shape of a colloidal nanocatalyst reveal the nanocatalysis mechanism type: Homogeneous or heterogeneous?},
	journal = {Topics in Catalysis},
	volume = {48},
	number = {1-4},
	year = {2008},
	note = {Narayanan, Radha Tabor, Christopher El-Sayed, Mostafa A.},
	month = {May},
	pages = {60-74},
	abstract = {The surface energy of metallic nanocrystals is relatively high compared to bulk materials due to the metal-metal bond deficiency of the surface atoms. This results in an insufficient chemical valency. In addition, smaller nanoparticles possess a higher degree of curvature, weakening, the bonding of their surface atoms. This is especially true for non-spherical shapes, which are comprised of a large number of sharp corner and edge sites. These atomic sites possess higher surface energies due to the lower number of shared bonds with the nanoparticle, resulting in instability of the surface atoms and rendering them physically unstable and chemically active. In many instances, the constant "bombardment" of these surface atoms by the solvent molecules as well as by the reactant molecules when these nanocrystals are in colloidal solution could lead to surface atom dissolution, both physically and/or chemically. This phenomenon could alter the functionality of the metallic colloidal nanoparticle from supplying catalytically active sites (in heterogeneous catalysis) to serving as a reservoir of catalytically active species to the solution (in homogeneous catalysis). In the latter type, if the atoms of the nanocatalyst appear in the products, the nanoparticle is no longer a catalyst but a reactant. In this review we attempt to answer the question raised in the title by examining our Previous work on the changes in size, shape, and other physical and chemical properties of colloidal transition metal nanoparticles during the nanocatalysis of two fundamentally different and important reactions: (1) the gentle electron-transfer reaction at room temperature involving the reduction of hexacyanoferrate (III) ions with thiosulfate ions and (2) the more harsh Suzuki cross-coupling reaction between phenylboronic acid and iodobenzene that takes place at 100 degrees C for 12 h. Changes in the nanoparticle dimensions were followed with TEM and HRTEM. Raman and FTIR spectroscopies were used to follow the chemical changes. For each change, we will use the above definition to see if the observed change can help us determine whether the catalysis is homogeneous or heterogeneous.},
	isbn = {1022-5528},
	doi = {10.1007/s11244-008-9057-4},
	author = {Narayanan, Radha and Tabor, C. E. and El-Sayed, Mostafa A}
}
@article {1122,
	title = {A new catalytically active colloidal platinum nanocatalyst: The multiarmed nanostar single crystal},
	journal = {Journal of the American Chemical Society},
	volume = {130},
	number = {14},
	year = {2008},
	note = {Mahmoud, Mahmoud A. Tabor, Christopher E. El-Sayed, Mostafa A. Ding, Yong Wang, Zhong Lin},
	month = {Apr},
	pages = {4590-+},
	abstract = {Nanocatalysts that possess large amounts of atoms on sharp corners and edges and high indexed sites are known to be more catalytically active. We report here on a novel yet simple method to synthesize in large yields a very active platinum nanocatalyst; the multiarmed nanostar single crystal. We utilize a seed mediated method using tetrahedral nanoparticles that are also synthesized by a new and simple technique. High-resolution TEM shows that the nanostar has many arms, varying from a few to over 30, whereby even the largest ones :re found to have single-crystal structures. This strongly suggests that they are formed by a growth mechanism of the seed crystals and not by the aggregation of seed crystals, which should produce twinning planes. Due to the reduction reaction of ferricyanide by thiosulfate, the nanostars are found to have an activation energy, which is nearly 60\% of that of the tetrahedral seeds themselves, both having the same PVP capping agent. This is undoubtedly due to the multiarms with edges, corners, and the presence of high indexed facets in the nanostar catalyst.},
	isbn = {0002-7863},
	doi = {10.1021/ja710646t},
	author = {Mahmoud, M A and Tabor, C. E. and El-Sayed, Mostafa A and Ding, Y. and Wang, Z.L.}
}
@article {1136,
	title = {Change in titania structure from amorphousness to crystalline increasing photoinduced electron-transfer rate in dye-titania system},
	journal = {Journal of Physical Chemistry C},
	volume = {111},
	number = {26},
	year = {2007},
	note = {Nishikiori, Hiromasa Qian, Wei El-Sayed, Mostafa A. Tanaka, Nobuaki Fujii, Tsuneo},
	month = {Jul},
	pages = {9008-9011},
	abstract = {Thin titania gel films containing well-dispersed fluorescein dye were prepared by the sol-gel method and treated with steam to promote crystal growth of the titania particles. It is known that steam treatment converts the titania structure from amorphousness to crystalline. In the present study, such change is found to increase the rate of the photoinduced electron transfer from and to dispersed fluorescein dye molecules.},
	isbn = {1932-7447},
	doi = {10.1021/jp072625q},
	author = {Nishikiori, H. and Qian, Wei and El-Sayed, Mostafa A and Tanaka, N. and Fujii, T.}
}
@article {1134,
	title = {Dependence of the threshold energy of femtosecond laser ejection of gold nanoprisms from quartz substrates on the nanoparticle environment},
	journal = {Journal of Physical Chemistry C},
	volume = {111},
	number = {25},
	year = {2007},
	note = {Tabor, Christopher Qian, Wei El-Sayed, Mostafa A.},
	month = {Jun},
	pages = {8934-8941},
	abstract = {Recently, it was reported that gold nanoprisms in a monolayer array on a quartz substrate were ejected in air when irradiated with femtosecond laser pulses near their surface plasmon absorption maximum. It was deduced from the measured reduction in particle thickness upon irradiation that the ejection mechanism involved ablation of surface atoms from the gold particle, which generates an intense pressure at the particle-substrate interface. The present study reports on this phenomenon when the substrate-bound nanoparticle is immersed in a liquid environment. In this system, it is found that the nanoparticle ejection requires less than one tenth the energy required if the system was irradiated in air. The ejected nanoparticle is also found to increase in thickness instead of the decrease observed in air. These results suggest another photoinitiated ejection mechanism, different from surface ablation, when the particles are surrounded by a liquid environment. From this and other spectroscopic and microscopic results on the ejected nanoprisms, we suggest a mechanism that involves energy transfer from the photoexcited nanoprism to the solvent within cavities and defects at the particle-substrate interface. The hot-solvent molecules result in an intense pressure at the particle-substrate interface, resulting in particle ejection. Ejection is proposed to consist of two processes, namely nanoparticle-substrate dissociation and nanoparticle solvation and diffusion away from the substrate. These two processes have independently been studied as a function of solvent property.},
	isbn = {1932-7447},
	doi = {10.1021/jp070282q},
	author = {Tabor, C. E. and Qian, Wei and El-Sayed, Mostafa A}
}
@article {1155,
	title = {Using silica films and powders modified with benzophenone to photoreduce silver nanoparticles},
	journal = {Journal of Photochemistry and Photobiology a-Chemistry},
	volume = {181},
	number = {2-3},
	year = {2006},
	note = {Eustis, Susie Krylova, Galina Smirnova, Natalie Eremenko, Anna Tabor, Christopher Huang, Wenyu El-Sayed, Mostafa A.},
	month = {Jul},
	pages = {385-393},
	abstract = {Porous silica (SiO2 films and powders), modified with benzophenone (BP), facilitates the formation of stable sliver nanoparticles by taking advantage of the solid supported photosensitizer. The silica serves as a carrier for the BP into an aqueous solution and its subsequent removal. Benzophenone, bound to a silica film, was able to reduce silver ions to generate nanoparticles in solution, while silica powder with bound BP generates silver nanoparticles that are attracted to the silica. Silver nanoparticles are also fabricated in porous silica films by incorporating silver ions into the films before casting and then irradiating the film in a solution containing BP. From pH studies, it is concluded that the ketyl-radicals and anion-radicals of BP and IPA both take part in the reduction of silver ions. These synthetic studies provide a new photochemical reduction method by immobilizing the reactant on a silica surface allowing generation of silver nanoparticles in solution attached to powders or inside a film for catalytic applications or increased conductivity of silica films. (c) 2006 Elsevier B.V. All rights reserved.},
	isbn = {1010-6030},
	doi = {10.1016/j.jphotochem.2005.12.024},
	author = {Eustis, Susie and Krylova, G. and Smirnova, N. and Eremenko, A. and Tabor, C. E. and Huang, Wenyu and El-Sayed, Mostafa A}
}
@article {1225,
	title = {Probing the primary event in the photocycle of photoactive yellow protein using photochemical hole-burning technique},
	journal = {Photochemistry and Photobiology},
	volume = {72},
	number = {5},
	year = {2000},
	note = {Mascianglioli, T Devanathan, S Cusanovich, MA Tollin, G El-Sayed, MA},
	month = {Nov},
	pages = {639-644},
	abstract = {Photochemical hole-burning spectroscopy was used to study the excited-state electronic structure of the 4-hydroxycinnamyl chromophore in photoactive yellow protein (PYP), This system Is known to undergo a trans-to-cis isomerization process on a femtosecond-to-picosecond time scale, similar to membrane-bound rhodopsins, and is characterized by a broad featureless absorbance at 446 nm, Resolved vibronic structure was observed for the hole-burned spectra obtained when PYP in phosphate buffer at pH 7 was frozen at low temperature and irradiated with narrow bandwidth laser light at 331 nm, The approximate homogeneous width of 752 cm(-1) could be calculated From the deconvolution of the hole-burned spectra leading to an estimated dephasing time of similar to 14 fs for the PYP excited-state structure. The resolved vibronic structure also enabled us to obtain an estimated change in the C=C stretching frequency, from 1663 cm(-1) in the ground state to similar to 1429 cm(-1) upon photoexcitation. The results obtained allowed us to speculate about the excited-state structure of PYP, We discuss the data for PYP in relation to the excited-state model proposed for the photosynthetic membrane protein bacteriorhodopsin, and use it to explain the primary event in the function of photoactive biological protein systems. Photoexcitation was also carried out at 475 nm, The vibronic structure obtained was quite different both in terms of the frequencies and Franck-Condon envelope. The origin of this spectrum was tentatively assigned.},
	isbn = {0031-8655},
	doi = {10.1562/0031-8655(2000)072<0639:ptpeit>2.0.co;2},
	author = {Mascianglioli, T. and Devanathan, S. and Cusanovich, M. A. and Tollin, G. and El-Sayed, Mostafa A}
}
@article {1287,
	title = {Fourier Transform Infrared Spectroscopic Studies of the Effect of Ca2+ Binding on the States of Aspartic Acid Side Chains in Bacteriorhodopsin},
	journal = {The Journal of Physical Chemistry},
	volume = {99},
	year = {1995},
	note = {doi: 10.1021/j100019a066},
	month = {1995},
	pages = {7776 - 7781},
	publisher = {American Chemical Society},
	abstract = {View http://dx.doi.org/10.1021/j100019a066 for article{\textquoteright}s front page in lieu of an abstract},
	isbn = {0022-3654},
	doi = {doi: 10.1021/j100019a066},
	url = {http://dx.doi.org/10.1021/j100019a066},
	author = {Masuda, Satoshi and Nara, Masayuki and Tasumi, Mitsuo and El-Sayed, Mostafa A and Lanyi, Janos K.}
}
@book {1285,
	title = {Ultrafast Processes in Chemistry and Photobiology},
	year = {1995},
	publisher = {Blackwell Science},
	organization = {Blackwell Science},
	abstract = {This new volume continues the tradition of the {\textquoteright}Chemistry for the 21st Century{\textquoteright} Series in exploring areas of active research in chemistry today which are likely to have a profound effect on the science of chemistry in the future. Lasers have had, and will have, a positive impact on chemistry with the short pulse width of the laser enabling chemists to measure the primary processes of important chemical changes. This use of lasers to measure ultrafast processes in chemistry and photobiology is one of the most active as well as one of the most fundamental field of research. This volume presents expert contributions summarizing the state-of-the-art in this most important area.},
	isbn = {086542893X},
	author = {El-Sayed, Mostafa A and Tanaka, I. and Molin, I.U.N.}
}
