Absorption and scattering properties of nanoparticles in an absorbing medium: modeling with experimental validation

Fuente: arXiv
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Auteurs principaux: Pham, Thi Hong, Kien, Nguyen Trung, Tuyen, Nguyen Viet, Nguyen, Hung Q., Nghiem, H. T. M.
Format: Preprint
Publié: 2024
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author Pham, Thi Hong
Kien, Nguyen Trung
Tuyen, Nguyen Viet
Nguyen, Hung Q.
Nghiem, H. T. M.
author_facet Pham, Thi Hong
Kien, Nguyen Trung
Tuyen, Nguyen Viet
Nguyen, Hung Q.
Nghiem, H. T. M.
contents Absorption and scattering properties of nanoparticles immersed in an absorbing medium are essential in understanding the overall properties of composites and in designing materials with expected functionalities. In this paper, we establish a model based on both Kubelka-Munk theory and Mie theory that links the absorption and scattering properties of individual particles with the reflectance and transmittance spectra of its thin-film composite, supported by detailed experiments. Thin films consisting of TiO$_2$ nanoparticles embedded in PMMA are fabricated on glass substrates using spin-coating and then peeled off to form standalone samples for spectroscopy measurements. By using the Kubelka-Munk theory in combination with the Saunderson correction, the absorption $K$ and scattering $S$ coefficients of multiple nanoparticles are extracted from the measured transmittance and reflectance. On the other hand, the absorption $K$ and scattering $S$ coefficients are the sum of absorption and scattering cross-sections of individual particles, which are calculated from the Mie theory specified for particles in an absorbing medium, with the scattering $S$ coefficient further modulated by the anisotropy factor $g$. The effect of the particulate medium is incorporated through an effective refractive index. The overall model is validated by matching well between the $K-S$ coefficients extracted from experimental data and theoretical calculations. This agreement provides deep insight into the significant attenuating effect of absorption and scattering on each particle due to the surrounding medium. The validated model of nanoparticles immersed in an absorbing medium can be used to obtain preliminary results for materials designed in a number of applications, such as radiative cooling.
format Preprint
id arxiv_https___arxiv_org_abs_2408_04248
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Absorption and scattering properties of nanoparticles in an absorbing medium: modeling with experimental validation
Pham, Thi Hong
Kien, Nguyen Trung
Tuyen, Nguyen Viet
Nguyen, Hung Q.
Nghiem, H. T. M.
Optics
Applied Physics
Absorption and scattering properties of nanoparticles immersed in an absorbing medium are essential in understanding the overall properties of composites and in designing materials with expected functionalities. In this paper, we establish a model based on both Kubelka-Munk theory and Mie theory that links the absorption and scattering properties of individual particles with the reflectance and transmittance spectra of its thin-film composite, supported by detailed experiments. Thin films consisting of TiO$_2$ nanoparticles embedded in PMMA are fabricated on glass substrates using spin-coating and then peeled off to form standalone samples for spectroscopy measurements. By using the Kubelka-Munk theory in combination with the Saunderson correction, the absorption $K$ and scattering $S$ coefficients of multiple nanoparticles are extracted from the measured transmittance and reflectance. On the other hand, the absorption $K$ and scattering $S$ coefficients are the sum of absorption and scattering cross-sections of individual particles, which are calculated from the Mie theory specified for particles in an absorbing medium, with the scattering $S$ coefficient further modulated by the anisotropy factor $g$. The effect of the particulate medium is incorporated through an effective refractive index. The overall model is validated by matching well between the $K-S$ coefficients extracted from experimental data and theoretical calculations. This agreement provides deep insight into the significant attenuating effect of absorption and scattering on each particle due to the surrounding medium. The validated model of nanoparticles immersed in an absorbing medium can be used to obtain preliminary results for materials designed in a number of applications, such as radiative cooling.
title Absorption and scattering properties of nanoparticles in an absorbing medium: modeling with experimental validation
topic Optics
Applied Physics
url https://arxiv.org/abs/2408.04248