cleavage, thermal chemical vapor deposition techniques (TCVD), plasma enhanced
chemical vapor deposition techniques (PCVD), chemical methods, electrochemical
process, etc. [22–25].
Graphene and functionalized graphene as a novel substrate for plasmonic
nanoparticles decoration have been well studied and explored. Also, the 2D surface
of these materials shows strong non-covalent affinity towards biomolecules, plasmonic nanoparticles (like Au, Ag, Cu, etc.) via p-p interaction, d electron -pp interaction, electrostatic force or sometimes hydrogen bonding, which provide an
excellent platform for conjugation [26]. Thus, the graphene/metal top surface (e.g.,
Au, Ag monometallic or bimetallic) of such structures easily can be modified for
chemical and biological sensing applications. Graphene interacted with plasmonic
nanoparticles through localized surface plasmon resonance (LSPR) mechanism,
offers a great platform for sensing applications like chemical-sensors, bio-sensors,
etc. It is also used in transparent, physically flexible, and tunable (chemical)
materials in electronics applications. The optical-electrical phenomenon arose when
light interacts with a metal surface is called Surface Plasmon Resonance (SPR) [27].
These high charge density oscillations at metal-dielectric (or metal/vacuum) interface propagated in a parallel direction or the metal-dielectric interfaces. That’s why
SPR techniques are very sensitive to any change occurred in the boundary of the
interfaces, for example, such as adsorption of nanoparticles to the 2D nanosheets.
The 2D graphene, GO, and 0D GQDs as a fluorescence, colorimetric, and electrochemical sensing platform have attracted the attention of the scientific community
recently. These three detection techniques are mostly discussed in this chapter for the
sensing of water pollutant. The fluorescent (optical) detection techniques have been
recognized as promising and powerful tools for quantitative detection of anions and
cations. Depending on the design of the nanomaterials optical method can be divided
into three techniques, such as colorimetric, fluorometric, and chemiluminescent
methods. The GO and GQDs are reported as fluorescent materials when their lateral
size dimension becomes few nanometers. Thus, graphene-based materials decoration with plasmonic nanoparticles has been used in fluorescence sensing applications
[28]. Again peroxidase mimic property (as artificial nanozyme) of plasmonic
nanoparticles decorated graphene and their applicability in colorimetric sensing
(naked eye detection) for water pollutant are well established. This interesting
property of these nanomaterials can be analyzed by a redox reaction caused by
reduction of H 2 O 2 in the presence of oxidation of a variety of chromogenic substrates like pyrogallol, O-phenylenediamine (OPD), 3,3′,5,5′-tetramethylbenzidine
(TMB), and 2,2′-azino-bis-(3-ethyl benzothiazoline-6-sulfonic acid) (ABTS), to
produce orange, blue and green colour suspension respectively. It is interesting to
note that compared to other substrates, TMB is less carcinogenic as well as products
have high absorption coefficient value. Thus, it is the most common chromogen used
to study horseradish peroxidase (HRP) mimics, in acidic conditions for naked-eye
detection of ions and biomolecules. Usually, graphene decorated with monometallic
or bimetallic nanoparticles shows better peroxidase mimic activity compared to bare
graphene sheets [29, 30]. Generally, electrochemical sensor based on particularly
stripping voltammetry technique and regarded as a very useful tool for on-site
Plasmonic Nanoparticles Decorated Graphene Sheets for Detection …
81
chemical vapor deposition techniques (PCVD), chemical methods, electrochemical
process, etc. [22–25].
Graphene and functionalized graphene as a novel substrate for plasmonic
nanoparticles decoration have been well studied and explored. Also, the 2D surface
of these materials shows strong non-covalent affinity towards biomolecules, plasmonic nanoparticles (like Au, Ag, Cu, etc.) via p-p interaction, d electron -pp interaction, electrostatic force or sometimes hydrogen bonding, which provide an
excellent platform for conjugation [26]. Thus, the graphene/metal top surface (e.g.,
Au, Ag monometallic or bimetallic) of such structures easily can be modified for
chemical and biological sensing applications. Graphene interacted with plasmonic
nanoparticles through localized surface plasmon resonance (LSPR) mechanism,
offers a great platform for sensing applications like chemical-sensors, bio-sensors,
etc. It is also used in transparent, physically flexible, and tunable (chemical)
materials in electronics applications. The optical-electrical phenomenon arose when
light interacts with a metal surface is called Surface Plasmon Resonance (SPR) [27].
These high charge density oscillations at metal-dielectric (or metal/vacuum) interface propagated in a parallel direction or the metal-dielectric interfaces. That’s why
SPR techniques are very sensitive to any change occurred in the boundary of the
interfaces, for example, such as adsorption of nanoparticles to the 2D nanosheets.
The 2D graphene, GO, and 0D GQDs as a fluorescence, colorimetric, and electrochemical sensing platform have attracted the attention of the scientific community
recently. These three detection techniques are mostly discussed in this chapter for the
sensing of water pollutant. The fluorescent (optical) detection techniques have been
recognized as promising and powerful tools for quantitative detection of anions and
cations. Depending on the design of the nanomaterials optical method can be divided
into three techniques, such as colorimetric, fluorometric, and chemiluminescent
methods. The GO and GQDs are reported as fluorescent materials when their lateral
size dimension becomes few nanometers. Thus, graphene-based materials decoration with plasmonic nanoparticles has been used in fluorescence sensing applications
[28]. Again peroxidase mimic property (as artificial nanozyme) of plasmonic
nanoparticles decorated graphene and their applicability in colorimetric sensing
(naked eye detection) for water pollutant are well established. This interesting
property of these nanomaterials can be analyzed by a redox reaction caused by
reduction of H 2 O 2 in the presence of oxidation of a variety of chromogenic substrates like pyrogallol, O-phenylenediamine (OPD), 3,3′,5,5′-tetramethylbenzidine
(TMB), and 2,2′-azino-bis-(3-ethyl benzothiazoline-6-sulfonic acid) (ABTS), to
produce orange, blue and green colour suspension respectively. It is interesting to
note that compared to other substrates, TMB is less carcinogenic as well as products
have high absorption coefficient value. Thus, it is the most common chromogen used
to study horseradish peroxidase (HRP) mimics, in acidic conditions for naked-eye
detection of ions and biomolecules. Usually, graphene decorated with monometallic
or bimetallic nanoparticles shows better peroxidase mimic activity compared to bare
graphene sheets [29, 30]. Generally, electrochemical sensor based on particularly
stripping voltammetry technique and regarded as a very useful tool for on-site
Plasmonic Nanoparticles Decorated Graphene Sheets for Detection …
81