Ultrafast Thermal Analysis of Surface Functionalized Gold Nanorods in Aqueous Solution

Huang, Jingyu; Park, Jonglo; Wang, Wei; Murphy, Catherine J.; Cahill, David G.

doi:10.1021/nn304738u

Cited by 72 publications

(96 citation statements)

References 58 publications

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“…32 On average, the AuNRs synthesized have dimensions of 5 x 30 nm (Supporting Figure 1). Prior to use, the excess cetyltrimethylammonium bromide (CTAB) capping agent was rinsed from the AuNRs by centrifugation in Milliipore water at 5,000x g for 25 min.…”

Section: Methodsmentioning

confidence: 99%

In Situ Detection and Identification of Hair Dyes Using Surface-Enhanced Raman Spectroscopy (SERS)

2015

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Hair is one of the most common types of physical evidence found at a crime scene. Forensic examination may suggest a connection between a suspect and a crime scene or victim, or it may demonstrate an absence of such associations. Therefore, forensic analysis of hair evidence is invaluable to criminal investigations. Current hair forensic examinations are primarily based on a subjective microscopic comparison of hair found at the crime scene with a sample of suspect's hair. Since this is often inconclusive, the development of alternative and more-accurate hair analysis techniques is critical. In this study, we utilized surface-enhanced Raman spectroscopy (SERS) to demonstrate that artificial dyes can be directly detected on hair. This spectroscopic technique is capable of a confirmatory identification of analytes with single molecule resolution, requires minimal sample, and has the advantage of fluorescence quenching. Our study reveals that SERS can (1) identify whether hair was artificially dyed or not, (2) determine if a permanent or semipermanent colorants were used, and (3) distinguish the commercial brands that are utilized to dye hair. Such analysis is rapid, minimally destructive, and can be performed directly at the crime scene. This study provides a novel perspective of forensic investigations of hair evidence.

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Section: Methodsmentioning

confidence: 99%

In Situ Detection and Identification of Hair Dyes Using Surface-Enhanced Raman Spectroscopy (SERS)

2015

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“…As shown in Figure 19, the TDTR signal is dominantly determined by the interfacial thermal conductance when delay time is longer than 2 ns. TDTR technique is therefore implemented extensively to study the thermal transport mechanisms across interfaces, including the effect of surface chemistry on interfacial thermal conductance across functionalized liquid-solid boundary [95,117,118] and solid-solid interfaces [119], interfacial thermal conductance between metals and dielectrics, [120][121][122][123][124] and interface between low dimensional materials and bulk substrates [125][126][127] Let's consider bulk materials first to introduce the physical picture we based on to determine heat capacity and thermal conductivity simultaneously. Under periodic laser heating, the penetration depth is defined as a characteristic length which describes the depth of temperature gradient penetrates into the sample can be written as , = √2 / 0 where 0 is the modulation frequency, is volumetric heat capacity and the index of directions corresponds to in-plane ( = ) and cross-plane ( = ) respectively.…”

Section: Transient Thermoreflectance Techniquementioning

confidence: 99%

Measurement Techniques for Thermal Conductivity and Interfacial Thermal Conductance of Bulk and Thin Film Materials

Zhao

Qian

et al. 2016

Journal of Electronic Packaging

384

222

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Thermal conductivity and interfacial thermal conductance play crucial roles in the design of engineering systems where temperature and thermal stress are of concerns. To date, a variety of measurement techniques are available for both bulk and thin film solid-state materials with a broad temperature range. For thermal characterization of bulk material, the steady-state method, transient hot-wire method, laser flash diffusivity method, and transient plane source method are most used.For thin film measurement, the 3ω method and the transient thermoreflectance technique including both time-domain and frequency-domain analysis are widely employed. This work reviews several most commonly used measurement techniques. In general, it is a very challenging task to determine thermal conductivity and interfacial thermal conductance with less than 5% error.Selecting a specific measurement technique to characterize thermal properties needs to be based on: 1) knowledge on the sample whose thermophysical properties is to be determined, including the sample geometry and size, and the material preparation method; 2) understanding of fundamentals and procedures of the testing technique, for example, some techniques are limited to samples with specific geometries and some are limited to a specific range of thermophysical properties; 3) understanding of the potential error sources which might affect the final results, for example, the convection and radiation heat losses.

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“…The two pulses have the same spectrum of 785 ± 1.5 nm and orthogonal circular polarization. The two beams are colinear; a transient absorption measurement is used to optimize the spatial overlap of the two pulses within the sample cell (46). We set the zero of delay time at the position of the maximum of the signal.…”

mentioning

confidence: 99%

Resonant secondary light emission from plasmonic Au nanostructures at high electron temperatures created by pulsed-laser excitation

Huang¹,

Wang

Murphy³

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

139

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Plasmonic nanostructures are of great current interest as chemical sensors, in vivo imaging agents, and for photothermal therapeutics. We study continuous-wave (cw) and pulsed-laser excitation of aqueous suspensions of Au nanorods as a model system for secondary light emission from plasmonic nanostructures. Resonant secondary emission contributes significantly to the background commonly observed in surface-enhanced Raman scattering and to the light emission generated by pulsed-laser excitation of metallic nanostructures that is often attributed to two-photon luminescence. Spectra collected using cw laser excitation at 488 nm show an enhancement of the broad spectrum of emission at the electromagnetic plasmon resonance of the nanorods. The intensity of anti-Stokes emission collected using cw laser excitation at 785 nm is described by a 300 K thermal distribution of excitations. Excitation by subpicosecond laser pulses at 785 nm broadens and increases the intensity of the anti-Stokes emission in a manner that is consistent with electronic Raman scattering by a high-temperature distribution of electronic excitations predicted by a two-temperature model. Broadening of the pulse duration using an etalon reduces the intensity of anti-Stokes emission in quantitative agreement with the model. Experiments using a pair of subpicosecond optical pulses separated by a variable delay show that the timescale of resonant secondary emission is comparable to the timescale for equilibration of electrons and phonons.gold nanorods | electron-hole pairs | surface-enhanced Raman scattering background

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Ultrafast Thermal Analysis of Surface Functionalized Gold Nanorods in Aqueous Solution

Cited by 72 publications

References 58 publications

In Situ Detection and Identification of Hair Dyes Using Surface-Enhanced Raman Spectroscopy (SERS)

In Situ Detection and Identification of Hair Dyes Using Surface-Enhanced Raman Spectroscopy (SERS)

Measurement Techniques for Thermal Conductivity and Interfacial Thermal Conductance of Bulk and Thin Film Materials

Resonant secondary light emission from plasmonic Au nanostructures at high electron temperatures created by pulsed-laser excitation

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