Hot Brownian Particles and Photothermal Correlation Spectroscopy

Radünz, Romy; Rings, Daniel; Kroy, Klaus; Cichos, Frank

doi:10.1021/jp810466y

Cited by 62 publications

(77 citation statements)

References 30 publications

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“…The sharp separation of the two lobes also considerably extends recently developed photothermal correlation spectroscopy techniques. 12 Besides the commonly calculated autocorrelation of the signal magnitude, cross-correlations of positive and negative signals become accessible and allow for the detection of anisotropic and directed motion with unprecedented accuracy (to be published). Accordingly, it is apparent that the careful control and understanding of the photothermal signal generation mechanism would provide great value for these applications or even pave the way for new developments.…”

Section: Articlementioning

confidence: 99%

“…At higher numerical apertures (i.e., NA d = 0.8), the interference contribution determines the photothermal signal up to a temperature rise of about 50 K. Above this temperature scattering contributes more than 10% and increases strongly. Therefore, the scattering intensity from the refractive index profile is relevant to a number of experiments 12,13,27,28 and cannot be neglected for quantitative data analysis. The nonlinear dependence of scattering and interference contributions to the total signal at moderate temperature rises is directly related to the inverse distance dependence of the refractive index change which involves a diverging length scale.…”

Section: Articlementioning

confidence: 99%

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Photothermal Single-Particle Microscopy: Detection of a Nanolens

2012

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Combining quantitative photothermal microscopy and light scattering microscopy as well as accurate MIE scattering calculations on single gold nanoparticles, we reveal that the mechanism of photothermal single-molecule/particle detection is quantitatively explained by a nanolensing effect. The lensing action is the result of the long-range character of the refractive index profile. It splits the focal detection volume into two regions. Our results lay the foundation for future developments and quantitative applications of single-molecule absorption microscopy.

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Section: Articlementioning

confidence: 99%

Section: Articlementioning

confidence: 99%

Photothermal Single-Particle Microscopy: Detection of a Nanolens

2012

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“…[22][23][24][25][26] Photothermal microscopy is one of the methods allowing background-free detection of absorbers at room temperature and in the absence of residual absorption by the sample [18,[27][28][29][30][31][32][33] with a sensitivity reaching the single-molecule level. [34] Further developments of this technique, including photothermal correlation spectroscopy, [35][36][37] photothermal tracking, [38] wide-field photothermal detection, [39] and its combination with fluorescence microscopy make photothermal microscopy a valuable tool in a large variety of applications. In this work, we simultaneously detected absorption and fluorescence signals from the same single gold NPs, which allows us to estimate directly their luminescence quantum yield.…”

Section: Introductionmentioning

confidence: 99%

Correlated Absorption and Photoluminescence of Single Gold Nanoparticles

2011

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We perform simultaneous absorption (photothermal) and fluorescence detection of gold nanospheres with diameters of 80, 60, 40, 20, 10, and 5 nm. We unambiguously identify the same individual nanoparticles (NPs) over large areas (>400 μm(2)) by means of atomic force microscopy (AFM) and optical absorption (photothermal) microscopy. We correlate the height of NPs measured with AFM with absorption and fluorescence signals from the same individual NPs. That allows us to compare their brightness and estimate their fluorescence quantum yield at the single NP level.

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“…More generally, heat transfer from nanoparticles or nanostructures to a fluid environment is a subject of active research, stimulated by the development of experimental techniques such as time-resolved optical absorption or reflectivity or photothermal correlation spectroscopy (5). Applications include, e.g., the enhancement of cooling from structured surfaces, local heating of fluids by selective absorption from nanoparticles, with possible biomedical hyperthermia uses (6,7).…”

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Heat transfer from nanoparticles: A corresponding state analysis

Mérabia

Shenogin

Joly

et al. 2009

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

199

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In this contribution, we study situations in which nanoparticles in a fluid are strongly heated, generating high heat fluxes. This situation is relevant to experiments in which a fluid is locally heated by using selective absorption of radiation by solid particles. We first study this situation for different types of molecular interactions, using models for gold particles suspended in octane and in water. As already reported in experiments, very high heat fluxes and temperature elevations (leading eventually to particle destruction) can be observed in such situations. We show that a very simple modeling based on Lennard-Jones (LJ) interactions captures the essential features of such experiments and that the results for various liquids can be mapped onto the LJ case, provided a physically justified (corresponding state) choice of parameters is made. Physically, the possibility of sustaining very high heat fluxes is related to the strong curvature of the interface that inhibits the formation of an insulating vapor film.interfaces ͉ liquids ͉ Kapitsa resistance S ubmicron-scale heat transfer is attracting a growing interest, motivated by both fundamental and technological points of view. In fluids, considerable attention has been devoted to the so-called nanofluids (1, 2), in which nanoparticles in dilute suspension appear to modify both bulk heat transfer and critical heat fluxes. Although the former effect can presumably be understood in terms of particle aggregation (3, 4), the latter is still poorly understood.More generally, heat transfer from nanoparticles or nanostructures to a fluid environment is a subject of active research, stimulated by the development of experimental techniques such as time-resolved optical absorption or reflectivity or photothermal correlation spectroscopy (5). Applications include, e.g., the enhancement of cooling from structured surfaces, local heating of fluids by selective absorption from nanoparticles, with possible biomedical hyperthermia uses (6, 7). Recent experiments demonstrated the possibility of reaching very high local temperatures by using laser heating of nanoparticles (8-10), even reaching the melting point of gold particles suspended in water. From a conceptual point of view, such experiments raise many interesting questions compared with usual, macroscopic heattransfer experiments. How are the phase diagram and heattransfer equations modified at small scales? How relevant is the presence of interfacial resistances, and how do they change with temperature?The case of nanofluids (11) is a good illustration of the role that can be played by molecular simulation in the interpretation of such complex situations. Although many interpretations have been proposed to explain the reported experimental results, it is only simulation of simple models that has been able to disprove some of these interpretations and to demonstrate the validity of the alternative, aggregation scenario. Interestingly, the use of complex models with accurate interaction force fields is not, in genera...

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Hot Brownian Particles and Photothermal Correlation Spectroscopy

Cited by 62 publications

References 30 publications

Photothermal Single-Particle Microscopy: Detection of a Nanolens

Photothermal Single-Particle Microscopy: Detection of a Nanolens

Correlated Absorption and Photoluminescence of Single Gold Nanoparticles

Heat transfer from nanoparticles: A corresponding state analysis

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