TY - JOUR T1 - Observation of Photoinduced Proton Transfer between the Titania Surface and Dye Molecule JF - The Journal of Physical Chemistry C Y1 - 2020 A1 - Nishikiori, H. A1 - Kondo, H. A1 - Kageshima, Y. A1 - Hooshmand, N. A1 - Panikkanvalappil, S. R. A1 - Valverde-Chávez, D.A. A1 - Silva, C. A1 - El-Sayed, M.A. A1 - Teshima,K. ER - TY - JOUR T1 - Operando Investigation into Dynamic Evolution of Cathode–Electrolyte Interfaces in a Li-Ion Battery JF - Nano letters Y1 - 2019 A1 - Chen, D. A1 - Mahmoud, M.A. A1 - Wang, J.H. A1 - Waller, G.H. A1 - Zhao, B. A1 - Qu, C. A1 - El-Sayed, M.A. A1 - Liu, M. ER - TY - JOUR T1 - On-Resonance Chiral Metamaterial for Chiroptical Sensing at the Molecular Level JF - CLEO: QELS Fundamental Science Y1 - 2017 A1 - Mousavi, H A1 - et al. ER - TY - JOUR T1 - Optimizing the antitumor efficacy of AuNR-assisted plasmonic photothermal therapy and its molecular impact JF - Cancer Research Y1 - 2016 A1 - Rahman, MA A1 - et al. ER - TY - JOUR T1 - Observing Real-Time Molecular Event Dynamics of Apoptosis in Living Cancer Cells using Nuclear-Targeted Plasmonically Enhanced Raman Nanoprobes JF - ACS nano Y1 - 2014 A1 - Kang, Bin A1 - Austin, Lauren A1 - El-Sayed, Mostafa A. VL - 8 SN - 1936-0851 J1 - ACS Nano ER - TY - JOUR T1 - The optical, photothermal, and facile surface chemical properties of gold and silver nanoparticles in biodiagnostics, therapy, and drug delivery JF - Archives of Toxicology Y1 - 2014 A1 - Austin, Lauren A1 - Mackey, Megan A. A1 - Dreaden, Erik C. A1 - El-Sayed, Mostafa A. SN - 0340-5761 J1 - Arch. Toxicol. ER - TY - JOUR T1 - The one dimensional photofragment translational spectroscopic technique: intramolecular clocking of energy redistribution for molecules falling apart1 JF - Time-of-Flight Mass Spectrometry and its Applications Y1 - 2012 A1 - Hwangl, Hyun Jin A1 - Grifliths, Jennifer A1 - El-Sayed, M. A. SN - 0444596186 ER - TY - JOUR T1 - Observation of optical gain in solutions of CdS quantum dots at room temperature in the blue region JF - Applied Physics Letters Y1 - 2006 A1 - Darugar, Q. A1 - Qian, Wei A1 - El-Sayed, Mostafa A AB - The optical gain dynamics has been studied for two CdS quantum dot samples dispersed in toluene at room temperature. This was carried out by using femtosecond transient absorption technique with an excitation at 400 nm and gain measurement was studied at the fluorescence maxima (440 and 460 nm). The optical gain lifetime was found to be as long as 20 ps under pump fluence as low as 0.77 mJ/cm(2). The low threshold is the result of long lifetime of electrons and holes and narrow emission bandwidth. These results suggest that CdS quantum dots in solution are excellent gain media for optically pumped high power blue lasers. VL - 88 SN - 0003-6951 N1 - Darugar, Q Qian, W El-Sayed, MA M3 - 10.1063/1.2217138 ER - TY - JOUR T1 - The Optically Detected Coherent Lattice Oscillations in Silver and Gold Monolayer Periodic Nanoprism Arrays:  The Effect of Interparticle Coupling JF - The Journal of Physical Chemistry B Y1 - 2005 A1 - Huang, Wenyu A1 - Qian, Wei A1 - El-Sayed, Mostafa A AB - Using femtosecond transient spectroscopy, we studied the optically detected laser-induced coherent phonon oscillation of monolayers of periodic arrays of prismatic-shaped silver and gold nanoparticles, assembled by using the technique of nanosphere lithography. In this method, the same size of polystyrene sphere and the same vacuum conditions are used. Under these circumstances, the gold nanoprisms formed are found to have sharper tips than the corresponding silver nanoprisms. For both gold and silver nanoparticles, the surface plasmon absorption maximum is found to depend linearly on size. The coherent lattice oscillation periods are also found to depend linearly on size. However, although the observed dependence for the silver nanoparticle is found to follow the calculated dependence of a single particle on size (based on a one-dimensional standing wave model), the gold nanoparticle deviates from this model, and the deviation is found to increase with the size of the nanoparticles. This deviation can be explained by considering interparticle coupling. A simple interparticle lattice oscillating dipolar coupling model of the dimer is found to qualitatively account for both the sign and the size dependence of the deviation. The absence of this deviation in the silver nanoparticle arrays is blamed on the weak interparticle coupling due to their rounded tips and the possibility of oxidation of their surfaces.Using femtosecond transient spectroscopy, we studied the optically detected laser-induced coherent phonon oscillation of monolayers of periodic arrays of prismatic-shaped silver and gold nanoparticles, assembled by using the technique of nanosphere lithography. In this method, the same size of polystyrene sphere and the same vacuum conditions are used. Under these circumstances, the gold nanoprisms formed are found to have sharper tips than the corresponding silver nanoprisms. For both gold and silver nanoparticles, the surface plasmon absorption maximum is found to depend linearly on size. The coherent lattice oscillation periods are also found to depend linearly on size. However, although the observed dependence for the silver nanoparticle is found to follow the calculated dependence of a single particle on size (based on a one-dimensional standing wave model), the gold nanoparticle deviates from this model, and the deviation is found to increase with the size of the nanoparticles. This deviation can be explained by considering interparticle coupling. A simple interparticle lattice oscillating dipolar coupling model of the dimer is found to qualitatively account for both the sign and the size dependence of the deviation. The absence of this deviation in the silver nanoparticle arrays is blamed on the weak interparticle coupling due to their rounded tips and the possibility of oxidation of their surfaces. PB - American Chemical Society VL - 109 SN - 1520-6106 UR - http://dx.doi.org/10.1021/jp0526647 CP - 40 N1 - doi: 10.1021/jp0526647 J1 - J. Phys. Chem. B M3 - 10.1021/jp0526647 ER - TY - Generic T1 - Optically detected coherent picosecond lattice oscillations in two dimensional arrays of gold nanocrystals of different sizes and shapes induced by femtosecond laser pulses T2 - Proceedings of SPIE Y1 - 2005 A1 - Huang, Wenyu A1 - Qian, Wei A1 - El-Sayed, Mostafa A AB - The nanosphere lithography (NSL) technique is used to make periodic gold array of prismatic nanoparticles. We use the femtosecond time resolved double beam transient optical detection to determine the coherent lattice oscillation in gold nanoparticles. Coherent lattice oscillation is compared on gold nanoparticles of different sizes and shapes. The effect of changing shape on the oscillation period was studied. Different environmental effects on the coherent lattice oscillation are eliminated by measuring the oscillation of the prismatic shape before and after we anneal it to spherical shape of the same number of atoms. A large change in the oscillation period is observed which agrees with the calculated period using different equations for the corresponding shapes. JA - Proceedings of SPIE VL - 5927 UR - http://dx.doi.org/10.1117/12.620501 M3 - 10.1117/12.620501 ER - TY - JOUR T1 - Optical Properties and Ultrafast Dynamics of Metalic Naocrystals JF - Annual Review of Physical Chemistry Y1 - 2003 A1 - Link, Stephan A1 - El-Sayed, Mostafa A AB - ? Abstract? Noble metal particles have long fascinated scientists because of their intense color, which led to their application in stained glass windows as early as the Middle Ages. The recent resurrection of colloidal and cluster chemistry has brought about the strive for new materials that allow a bottoms-up approach of building improved and new devices with nanoparticles or artificial atoms. In this review, we discuss some of the properties of individual and some assembled metallic nanoparticles with a focus on their interaction with cw and pulsed laser light of different energies. The potential application of the plasmon resonance as sensors is discussed.? Abstract? Noble metal particles have long fascinated scientists because of their intense color, which led to their application in stained glass windows as early as the Middle Ages. The recent resurrection of colloidal and cluster chemistry has brought about the strive for new materials that allow a bottoms-up approach of building improved and new devices with nanoparticles or artificial atoms. In this review, we discuss some of the properties of individual and some assembled metallic nanoparticles with a focus on their interaction with cw and pulsed laser light of different energies. The potential application of the plasmon resonance as sensors is discussed. PB - Annual Reviews VL - 54 SN - 0066-426X UR - http://dx.doi.org/10.1146/annurev.physchem.54.011002.103759 CP - 1 N1 - doi: 10.1146/annurev.physchem.54.011002.103759 J1 - Annu. Rev. Phys. Chem. ER - TY - JOUR T1 - Observation of large changes in the band gap absorption energy of small CdSe nanoparticles induced by the adsorption of a strong hole acceptor JF - Nano Letters Y1 - 2001 A1 - Landes, Christy F. A1 - Braun, Markus A1 - Burda, Clemens A1 - El-Sayed, Mostafa A AB - When butylamine In relatively high concentrations (0.1-0.25 M) is added to a colloidal solution of CdSe nanoparticles (NPs) that are approximately 1.6 nm in diameter, the band gap absorption changes from a broad, relatively weak absorption centered at 445 nm to a narrow, relatively strong absorption centered at 414 nm. The effect of concentration on the observed spectrum shows an isobestic point, suggesting an equilibrium between two species. The possible mechanisms for such a transformation are discussed. VL - 1 SN - 1530-6984 N1 - Landes, C Braun, M Burda, C El-Sayed, MA M3 - 10.1021/nl015619t ER - TY - JOUR T1 - Origin of emission from porous silicon: Temperature-dependence correlation with proton conductivity JF - Physical Review B Y1 - 2000 A1 - Zou, Bingsuo A1 - Wang, Jianping A1 - Liu, C. A1 - Zhang, J.Z. A1 - El-Sayed, Mostafa A AB - The excitation, emission, and Fourier transform infrared (FTIR) spectra of freshly prepared and aged porous silicon (PS) are examined. The effects of aging and temperature changing on the emission and excitation spectra of fresh and aged PS samples is also studied. Aging in air is found to result in a redshift in the emission spectrum, but a blueshift in the excitation spectrum. Increasing the temperatures leads to a general decrease in the emission intensities of both samples: however, the green emission of fresh sample shows an unusually large and sudden increase in its intensity at the same temperature at which the proton conductivity in the silicon wafer increases. The temperature dependence of the O-H vibration intensity of silicon wafers shows a sudden decrease at that temperature. These results are consistent with a model in which the excitation leads to the formation of exciton in the confined nanostructure, and the formation of electron and hole that are trapped by surface traps, whose nature is dependent on the chemical composition of the surface (and thus its age). These conclusions are confirmed by the results of the FTIR spectra of the two samples, the temperature dependence of the emission, and its correlation with the proton conductivity in the fresh PS. PB - APS VL - 62 UR - http://link.aps.org/doi/10.1103/PhysRevB.62.16595 CP - 24 M3 - 10.1103/PhysRevB.62.16595 ER - TY - JOUR T1 - Optical rotation of the second harmonic radiation from retinal in bacteriorhodopsin monomers in Langmuir-Blodgett film: evidence for nonplanar retinal structure. JF - Biophysical journal Y1 - 1997 A1 - Volkov, V. V. A1 - Svirko, Y P A1 - Kamalov, Valey F. A1 - Song, Li A1 - El-Sayed, Mostafa A KW - Bacteriorhodopsins KW - Biophysical Phenomena KW - Biophysics KW - Circular Dichroism KW - Molecular Structure KW - Optics and Photonics KW - Retinaldehyde KW - Spectrophotometry AB - We observed optical rotation of the plane of polarization of the second harmonic (SH) radiation at 532 nm (in resonance with the retinal absorption) generated in reflection geometry in Langmuir-Blodgett film of bacteriorhodopsin (bR). The analysis of the experimental data showed that this effect arises from the nonvanishing contribution of the antisymmetrical part of the hyperpolarizability tensor. This requires that the dipole moment of the resonant electronic transition, the change of the dipole moment upon electronic excitation, and the long axis of the retinal not be coplanar. Such conditions are satisfied only if the retinal has a nonplanar geometry, a conclusion that could lend support to the heterogeneity model of the origin of the biphasic band shape of the linear CD spectrum of the retinal in bR. On the basis of our theoretical analysis, we were able to estimate the angle between the induced dipole moment and the plan that contains the long axis of the chromophore and the transition dipole moment of the retinal absorption. VL - 73 CP - 6 U1 - http://www.ncbi.nlm.nih.gov/pubmed/9414228?dopt=Abstract M3 - 10.1016/S0006-3495(97)78342-5 ER -