Laser-Induced Size Reduction of Noble Metal Particles

Takami, Akinori; Kurita, and Hideaki; Koda, Seiichiro

doi:10.1021/jp983503o

Cited by 524 publications

(599 citation statements)

References 15 publications

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“…According to Mie theory and even more advanced theoretical models such as the effective medium model, smaller is the metallic nano-particles, blue is the shift of the plasmon frequency. This is evidenced clearly in some elegant experiments using nano or/and femtosec regimes of laser induced size reduction of noble metal particles (52)(53)(54). Figure 4 reports the experimental variation of the nano-gold surface plasmon wavelength versus temperature.…”

Section: Figurementioning

confidence: 78%

Surface Plasmon Resonance Tunability in Au−VO2 Thermochromic Nano-composites

Mâaza

Nemraoui²,

Sella

et al. 2005

Gold Bull

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A new type of photo-active nano-composite material appropriate for Ultra-fast Nonlinear Optical (3) ( ) applications has been synthesized and optically characterized. Compared to standard noble metal particles-oxide nano-composites exhibiting a superior effective (3) ( ) due to the enhancement of the local electric field, these Au-VO 2 nano-composites display an additional reversibly tunable surface plasmon frequency under external temperature stimuli. Such a smart plasmon tunability is correlated to the Mott's type semiconducting/metallic 1st order transition of the host VO 2 matrix. The nano-gold surface plasmon wavelength shifts reversibly from 645 nm to 598nm when the Au-VO 2 nano-composites temperature varies from 25°C to 120°C.

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Section: Figurementioning

confidence: 78%

Surface Plasmon Resonance Tunability in Au−VO2 Thermochromic Nano-composites

Mâaza

Nemraoui²,

Sella

et al. 2005

Gold Bull

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“…High-powered pulses shorter than a relaxation time of τ r = r p 2 /6.75α p for spheres of radius r p and thermal diffusivity α p rapidly heat individual NPs 9 which exhibit negligible conductive/convective and radiative heat loss on timescales <τ r . 27 Heating thus confined to a nanoparticle (NP) subsequently superheats a thin layer of adjacent fluid. At temperatures ~85% of Tcritical, pressure due to fluid surface tension, σ, given by p s = 2σ/r p , is overcome and adjacent fluid vaporizes.…”

Section: Introductionmentioning

confidence: 99%

Microscale Heat Transfer Transduced by Surface Plasmon Resonant Gold Nanoparticles

2007

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Visible radiation at resonant frequencies is transduced to thermal energy by surface plasmons on gold nanoparticles. Temperature in ≤10-microliter aqueous suspensions of 20-nanometer gold particles irradiated by a continuous wave Ar+ ion laser at 514 nm increased to a maximum equilibrium value. This value increased in proportion to incident laser power and in proportion to nanoparticle content at low concentration. Heat input to the system by nanoparticle transduction of resonant irradiation equaled heat flux outward by conduction and radiation at thermal equilibrium. The efficiency of transducing incident resonant light to heat by microvolume suspensions of gold nanoparticles was determined by applying an energy balance to obtain a microscale heat-transfer time constant from the transient temperature profile. Measured values of transduction efficiency were increased from 3.4% to 9.9% by modulating the incident continuous wave irradiation.

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“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] Time-resolved transient absorption spectroscopy allows one to follow the electronphonon relaxation dynamics in thin metal films [21][22][23][24] and small metal particles. [1][2][3][4][5][6][7][8][9][10][11][12][13] In particular, silver 1,2,9 and gold [2][3][4][5][6][7][8][10][11][12][13] nanoparticles have been studied intensively as they show a strong absorption band in the visible region, which is due to the excitation of the surface plasmon resonance.…”

Section: Introductionmentioning

confidence: 99%

“…However, if the pump power is increased significantly, the temperature of the metal nanoparticle lattice can be raised to values well above its melting temperature within a few picoseconds (when using ultrashort laser pulses) while the temperature of the environment initially remains constant. This can then lead to size [14][15][16][17] and shape [18][19][20] changes of the nanoparticles before the deposited laser energy can be released to the surrounding medium by phonon-phonon interactions which are usually on the order of 100 ps. 4,7 It was recently reported 29 that gold nanorods prepared by an electrochemical method 30 and encapsulated in micelles in aqueous solution undergo a rod-to-sphere shape transformation within about 30 ps due to melting of the nanorods.…”

Section: Introductionmentioning

confidence: 99%

Laser-Induced Shape Changes of Colloidal Gold Nanorods Using Femtosecond and Nanosecond Laser Pulses

2000

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Gold nanorods have been found to change their shape after excitation with intense pulsed laser irradiation. The final irradiation products strongly depend on the energy of the laser pulse as well as on its width. We performed a series of measurements in which the excitation power was varied over the range of the output power of an amplified femtosecond laser system producing pulses of 100 fs duration and a nanosecond optical parametric oscillator (OPO) laser system having a pulse width of 7 ns. The shape transformations of the gold nanorods are followed by two techniques: (1) visible absorption spectroscopy by monitoring the changes in the plasmon absorption bands characteristic for gold nanoparticles; (2) transmission electron microscopy (TEM) in order to analyze the final shape and size distribution. While at high laser fluences (∼1 J cm -2 ) the gold nanoparticles fragment, a melting of the nanorods into spherical nanoparticles (nanodots) is observed when the laser energy is lowered. Upon decreasing the energy of the excitation pulse, only partial melting of the nanorods takes place. Shorter but wider nanorods are observed in the final distribution as well as a higher abundance of particles having odd shapes (bent, twisted, φ-shaped, etc.). The threshold for complete melting of the nanorods with femtosecond laser pulses is about 0.01 J cm -2 . Comparing the results obtained using the two different types of excitation sources (femtosecond vs nanosecond laser), it is found that the energy threshold for a complete melting of the nanorods into nanodots is about 2 orders of magnitude higher when using nanosecond laser pulses than with femtosecond laser pulses. This is explained in terms of the successful competitive cooling process of the nanorods when the nanosecond laser pulses are used. For nanosecond pulse excitation, the absorption of the nanorods decreases during the laser pulse because of the bleaching of the longitudinal plasmon band. In addition, the cooling of the lattice occurring on the 100 ps time scale can effectively compete with the rate of absorption in the case of the nanosecond pulse excitation but not for the femtosecond pulse excitation. When the excitation source is a femtosecond laser pulse, the involved processes (absorption of the photons by the electrons (100 fs), heat transfer between the hot electrons and the lattice (<10 ps), melting (30 ps), and heat loss to the surrounding solvent (>100 ps) are clearly separated in time.

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Laser-Induced Size Reduction of Noble Metal Particles

Cited by 524 publications

References 15 publications

Surface Plasmon Resonance Tunability in Au−VO2 Thermochromic Nano-composites

Surface Plasmon Resonance Tunability in Au−VO2 Thermochromic Nano-composites

Microscale Heat Transfer Transduced by Surface Plasmon Resonant Gold Nanoparticles

Laser-Induced Shape Changes of Colloidal Gold Nanorods Using Femtosecond and Nanosecond Laser Pulses

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