Prof. H. Peter Lu Profile

Prof. H. Peter Lu

Senior Research Scientist at Bowling Green State Univ

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Publications (3)

Proceedings Article | 28 February 2006 Paper

Live cell imaging of the endocytosis and the intracellular trafficking of multifunctional lipid nanoparticles

Tieqiao Zhang, S. Narasimhan Danthi, Jianwu Xie, Dehong Hu, Peter Lu, King Li

Proceedings Volume 6095, 60950D (2006) https://doi.org/10.1117/12.645398

KEYWORDS: Nanoparticles, Particles, Luminescence, Microscopy, Live cell imaging, Medicine, Cancer, Oncology, Genetics, Diffusion

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Proceedings Article | 27 February 2006 Paper

Single molecule electron transfer process of ruthenium complexes

Dehong Hu, Peter Lu

Proceedings Volume 6092, 609207 (2006) https://doi.org/10.1117/12.638845

KEYWORDS: Molecules, Ruthenium, Quantum efficiency, Photodetectors, Phosphorescence, Transition metals, Single molecule spectroscopy, Continuous wave operation, Oxygen, Statistical analysis

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Proceedings Article | 19 June 2003 Paper

Nanosurface enhanced Raman scattering fluctuation dynamics

Leyun Zhu, Gregory Schenter, Miodrag Micic, Yung Suh, Nicholas Klymyshyn, H. Lu

Proceedings Volume 4962, (2003) https://doi.org/10.1117/12.478914

KEYWORDS: Molecules, Raman spectroscopy, Surface enhanced Raman spectroscopy, Nanoparticles, Silver, Raman scattering, Finite element methods, Particles, Molecular interactions, Optical spheres

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Here, we report our results on excitation intensity and nanoscale Ag cluster dependent spectral fluctuation dynamics of surface enhanced Raman scattering. We have studied single-Ag-cluster surface enhanced Raman scattering (SERS) intensity fluctuations under low molecule surface coverage of rhodamine 6G (R6G) and cytochrome c. By applying both experimental and theoretical approaches, we observed that spectral fluctuation phenomena are associated with SERS not only from single-molecule loaded nanoclusters but also from submonolayer molecule loaded nanoclusters. The nanoscale confinement of the local electric field enhancement under the laser excitation defines the SERS fluctuation. A new AFM-coupled two-channel photon time-stamping system, enabling in situ correlation of the topographic and spectroscopic information for single nanoparticle clusters, was used to record Raman intensity fluctuation trajectories at sub-μs resolution. Experimentally, we found that SERS fluctuation dynamics are highly inhomogeneous amongst nanocluster interstitial sites. Although the fluctuation above ~50 W/cm² excitation is dominated by photoinduced processes, spontaneous fluctuation can be observed at lower excitation intensity. Although a single Raman-active molecule confined within the volume of an electric field excitation gives a significant Raman spectral fluctuation, observation of the fluctuation alone may not be sufficient in identifying a single-molecule origin of a Raman spectrum. The Raman signal comes predominately from the localized electric field enhancement at interstitial sites, occuring in a very small volume at nanoscale (capable of holding only one or a few molecules), as estimated from finite-element methods simulations of an electric field enhancement using a classical electrodynamics approach. Such a small number of molecules, which are presumably under discrete diffusion and exposed to interactions with a locally strong electric field, results in the observed Raman fluctuation. The fluctuation autocorrelation amplitude is proportional to the reverse number of molecules confined at the volume of the electric field enhancement.

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