9
Optical Properties of Nanoparticles
9.1
General Remarks
In view of technical applications, the optical properties of nanoparticles and nanocomposites are of major interest. In addition to their economic importance, the
scientific background of these properties is of fundamental importance in order to
understand the behavior of nanomaterials.
When examining these optical properties, it is important to distinguish between
several major cases:
Adjustment of the index of refraction by adding nanoparticles to polymers.
Design of ultraviolet (UV) absorbers transparent for visible light.
Nanoparticulate pigments in transparent matrices.
Luminescent materials.
Photo- and electrochromic materials.
Bifunctional materials showing luminescence and ferromagnetic properties.
As the information relating to each of these examples is vast, only the most basic
facts will be explained at this point, although other optical properties will be
considered under one of the following topics.
9.2
Adjustment of the Index of Refraction
In many applications, it is necessary to adjust the index of refraction of a polymer
precisely to a given value. A typical example of this is the glue used to connect or fix
optical fibers for information transmission. One way to do this is to add nanoparticles with an index of refraction that differs from that of the polymer. At low
nanoparticle concentrations, the index of refraction of a composite n composite
consisting of a matrix with indices of refraction n matrix for the matrix and n particle
for the nanoparticles, may be estimated by:
n composite ¼ ð1 À cÞn matrix þ cn particle
ð9:1Þ
Nanomaterials: An Introduction to Synthesis, Properties and Applications, Second Edition. Dieter Vollath.
Ó 2013 Wiley-VCH Verlag GmbH & Co. KGaA. Published 2013 by Wiley-VCH Verlag GmbH & Co. KGaA.
j205
Optical Properties of Nanoparticles
9.1
General Remarks
In view of technical applications, the optical properties of nanoparticles and nanocomposites are of major interest. In addition to their economic importance, the
scientific background of these properties is of fundamental importance in order to
understand the behavior of nanomaterials.
When examining these optical properties, it is important to distinguish between
several major cases:
Adjustment of the index of refraction by adding nanoparticles to polymers.
Design of ultraviolet (UV) absorbers transparent for visible light.
Nanoparticulate pigments in transparent matrices.
Luminescent materials.
Photo- and electrochromic materials.
Bifunctional materials showing luminescence and ferromagnetic properties.
As the information relating to each of these examples is vast, only the most basic
facts will be explained at this point, although other optical properties will be
considered under one of the following topics.
9.2
Adjustment of the Index of Refraction
In many applications, it is necessary to adjust the index of refraction of a polymer
precisely to a given value. A typical example of this is the glue used to connect or fix
optical fibers for information transmission. One way to do this is to add nanoparticles with an index of refraction that differs from that of the polymer. At low
nanoparticle concentrations, the index of refraction of a composite n composite
consisting of a matrix with indices of refraction n matrix for the matrix and n particle
for the nanoparticles, may be estimated by:
n composite ¼ ð1 À cÞn matrix þ cn particle
ð9:1Þ
Nanomaterials: An Introduction to Synthesis, Properties and Applications, Second Edition. Dieter Vollath.
Ó 2013 Wiley-VCH Verlag GmbH & Co. KGaA. Published 2013 by Wiley-VCH Verlag GmbH & Co. KGaA.
j205