group (py-SH) was reported towards OFET designing to increase channel sensitivity to Hg
2+ ion. This material is capable of sensing Hg
2+ ion as low as 0.01 lM
[44].
8 1-D and 2-D Nanomaterials and Nanostructures
Class of 2-D nanomaterials contains Graphene, MoS 2 , phosphorene and many
more. All the 2-D structures impose best electrical and conduction properties which
makes them suitable choices. Among the all, graphene is the most preferred choice
of researchers.
Carbon nanostructures such as reduced graphene [45–50], CNT (single wall and
multiwall) structures [47, 51] were modified or anchored with biomolecules such
aptamers [52], peptides [45], DNAzyme [53, 54], nanoparticle [49, 54] and with
various polymers [46] to make sensor more sensitive and selective towards Hg
(II) [46, 47, 51–53], Cd (II) [48], Cu (II) [45], Ni (II) [45], Pb (II) [49, 51, 54].
In recent times, the 2D-layered transition-metal dichalcogenides (TMDs)
gained attention due to its tunable electronic properties, high swapping ratio
of *10
8 , carrier freedom of movement of 200 cm
2 V
−1 s
−1 [55–57]. These
exceptional features are making MoS 2 a hopeful material in future FET sensing.
Li et al. [57], has tried to explore the working and masking ability towards
Schottky barrier (SC). The author also tried explore its use as an ionosphere towards
As (III) with reported LOD of 0.1 ppb. Also, An and Jang [55] had designed a
sensor utilizing the properties of MoS 2 and conducting polymer carboxylic polypyrrole (CPPy). As it is using two electronically conducting entities, hence it will
result in extensively satisfying results. The electrode formed was named as carboxylic polypyrrole (CPPy)-coated flower-like MoS 2 Nano-spheres (CFMNSs) in
order to bind As (III) with LOD: 1 pM. Zhou et al. [56] had also used MoS 2
structure decorated with Au NPs and functionalised by DNA electrode and named it
hybrid FET towards sensing of Hg (II) with LOD: 9.9 nM and showed isolated
behaviour towards potential interfering metal ions such as As
5+ , Cd
2+ , Pb
2+ etc.
Black phosphorus (BP) is a material belongs to TMDs. Like graphene BP is also
have multilayers stacked together with Vander Waal interaction and can be exfoliated to mono or multilayered systems. BP shows better carrier mobility (1000 cm
2
V
−1 s
−1
) than conventional materials, larger current on/off ratio (1 Â 10
3 to
1 Â 10
5 ) than graphene and better molecule adsorption. Most fascinating feature is
its high surface to volume ratio for designing an ultrasensitive sensing platform
using BP. The biggest and the only limitation with BP is its physical stability [58].
Guihua Zhou et al. Had reported FET for As (III) ions, for that, BP film acts as
channel material although the probe dithiothreitol (DTT) decorated on gold
(Au) nanoparticles (NPs) acts as receptor for As (III). Author acclaimed the stable,
sensitive and selective probe for As (III) with LOD 1 nM [59]. Li et al. [58], had
Materials for Electrical Detection of Water Pollutants
117
2+ ion. This material is capable of sensing Hg
2+ ion as low as 0.01 lM
[44].
8 1-D and 2-D Nanomaterials and Nanostructures
Class of 2-D nanomaterials contains Graphene, MoS 2 , phosphorene and many
more. All the 2-D structures impose best electrical and conduction properties which
makes them suitable choices. Among the all, graphene is the most preferred choice
of researchers.
Carbon nanostructures such as reduced graphene [45–50], CNT (single wall and
multiwall) structures [47, 51] were modified or anchored with biomolecules such
aptamers [52], peptides [45], DNAzyme [53, 54], nanoparticle [49, 54] and with
various polymers [46] to make sensor more sensitive and selective towards Hg
(II) [46, 47, 51–53], Cd (II) [48], Cu (II) [45], Ni (II) [45], Pb (II) [49, 51, 54].
In recent times, the 2D-layered transition-metal dichalcogenides (TMDs)
gained attention due to its tunable electronic properties, high swapping ratio
of *10
8 , carrier freedom of movement of 200 cm
2 V
−1 s
−1 [55–57]. These
exceptional features are making MoS 2 a hopeful material in future FET sensing.
Li et al. [57], has tried to explore the working and masking ability towards
Schottky barrier (SC). The author also tried explore its use as an ionosphere towards
As (III) with reported LOD of 0.1 ppb. Also, An and Jang [55] had designed a
sensor utilizing the properties of MoS 2 and conducting polymer carboxylic polypyrrole (CPPy). As it is using two electronically conducting entities, hence it will
result in extensively satisfying results. The electrode formed was named as carboxylic polypyrrole (CPPy)-coated flower-like MoS 2 Nano-spheres (CFMNSs) in
order to bind As (III) with LOD: 1 pM. Zhou et al. [56] had also used MoS 2
structure decorated with Au NPs and functionalised by DNA electrode and named it
hybrid FET towards sensing of Hg (II) with LOD: 9.9 nM and showed isolated
behaviour towards potential interfering metal ions such as As
5+ , Cd
2+ , Pb
2+ etc.
Black phosphorus (BP) is a material belongs to TMDs. Like graphene BP is also
have multilayers stacked together with Vander Waal interaction and can be exfoliated to mono or multilayered systems. BP shows better carrier mobility (1000 cm
2
V
−1 s
−1
) than conventional materials, larger current on/off ratio (1 Â 10
3 to
1 Â 10
5 ) than graphene and better molecule adsorption. Most fascinating feature is
its high surface to volume ratio for designing an ultrasensitive sensing platform
using BP. The biggest and the only limitation with BP is its physical stability [58].
Guihua Zhou et al. Had reported FET for As (III) ions, for that, BP film acts as
channel material although the probe dithiothreitol (DTT) decorated on gold
(Au) nanoparticles (NPs) acts as receptor for As (III). Author acclaimed the stable,
sensitive and selective probe for As (III) with LOD 1 nM [59]. Li et al. [58], had
Materials for Electrical Detection of Water Pollutants
117