Temperature of a nanoparticle above a substrate under radiative heating and cooling

Abstract

Controlling the temperature in architectures involving nanoparticles and substrates is a key issue for applications involving micro and nanoscale heat transfer. We study the thermal behavior of a single nanoparticle interacting with a flat substrate under external monochromatic illumination, and with thermal radiation as the unique heat loss channel. We develop a model to compute the temperature of the nanoparticle, based on an effective dipole-polarizability approach. Using numerical simulations, we thoroughly investigate the impacts of various parameters affecting the nanoparticle temperature, such as the nanoparticle-to-substrate gap distance, the incident light wavelength and polarization, or the material resonances. This study provides a tool for the thermal characterization and design of micro or nanoscale systems coupling substrates with nanoparticles or optical antennas.

Observation of Undercooling in a Levitated Nanoscale Liquid Au Droplet

“…For T 0 = 1400 K, T f = 1125 K, m = 4 × 10 –17 kg, and t = 4.25 ms, we obtain Q abs. (λ = 532 nm) = 0.90, a value in reasonable agreement with values (≃0.75) reported for somewhat smaller particles. , …”

“…Over the limited range of T and m that is experimentally probed, the data can be effectively collapsed onto a scaled x -axis with x = S / [ m / m 0 ] 0.811 , where S is the laser power density. Since the absorption of visible light by a nanoparticle depends on multiple factors, including the radius and temperature of the nanoparticle, we have not attempted to derive an exact formula for the dependence of temperature on size. Instead, the scaling factor was determined empirically by fitting the data.…”

Exploiting gold nanoparticles for diagnosis and cancer treatments

“…As a resulting effect, the energy of the LSPR is released as heat, diffusing away from the NP and raising the temperature of the surrounding medium. The heating effect is maximal at the LSPR and represents the basic exploitation of plasmonic heating in the treatment of cells via PTT [54][55][56][57][58][59][60][61].…”

“…where h is the Planck's constant, c is the speed of light in vacuum, k B is the Boltzmann's constant, and e λ is the thermal emissivity. Since thermal emissivity and absorption efficiency Q abs of the NP are equals, we obtain the equation governing the NP temperature T [59]:…”

Detection of Intracellular Gold Nanoparticles: An Overview

“…The power absorbed by the AuNP is nearly proportional to the incident power carried by the external beam by the relation [ 64 ] where Q abs is the absorption efficiency given by Equation (1), I inc is the intensity of the external light beam, and the prefactor denotes the geometrical cross-section of the AuNP considered spherical in this case. The power thermally emitted by the AuNP at temperature T is given by the relation [ 65 ] where is the Planck’s constant, c is the speed of light in vacuum, e λ is the thermal emissivity and k B is the Boltzmann’s constant. It is reasonable to assume that the thermal emissivity is equal to absorption efficiency Q abs of the AuNP, hence inserting Equations (5) and (6) in Equation (4), we obtain where is the power density emitted by the AuNP before the illumination at the bath temperature T cell , and the denominator denotes the geometrical factor for a spherical NP, for NRs or NSs this factor should be changed accordingly.…”