In attempts to mimic the olfactory receptors, a broad range of electrochemical sensors made of different materials have been explored and designed. The most commonly used electrochemical sensors include metal oxide chemical semiconductors (eg SnO₂ and ZnO) [69, 97], organic effect transistors [98, 99], conductive polymers of both intrinsically conductive types (e. g. , polythiophenes), and Those combined with conductive particles (eg, graphene polymer composite or carbon nanotubes) [100-105]. The most common class of electrochemical sensors, metal oxide sensors (MOS), are chemical resistors that typically heat up and react with volatile organic analytes to alter electrical properties (eg, resistance or capacitance). Are [106-108]. The main problem with using conventional electrochemical sensors (for example, unmodified metal oxide sensors or conductive polymers) for chemical sensing has been the almost indistinguishable sensor responses among similar analytes. This is due to the nature of that particular type of sensor, which relies primarily on the physical absorption or nonspecific chemical interactions between chemical analytes and sensor receptors. Relying on physical absorption, in most cases, leads to poor selectivity of electrochemical sensors to target analytes as well as interference with ambient humidity, which in particular greatly limits the use of such sensors. In addition, the fundamental deviation of the sensor response due to aging is a major challenge for the development of electrochemical sensors. [76]
In attempts to mimic the olfactory receptors, a broad range of electrochemical sensors made of
different
materials have
been explored
and designed. The most
commonly
used
electrochemical sensors include metal oxide
chemical
semiconductors (
eg
SnO₂ and
ZnO
) [69, 97], organic effect transistors [98, 99], conductive polymers of both
intrinsically
conductive types (
e. g.
,
polythiophenes
), and Those combined with conductive particles (
eg
, graphene polymer composite or carbon nanotubes) [100-105]. The most common
class
of electrochemical sensors, metal oxide sensors (MOS), are
chemical
resistors that
typically
heat up and react with volatile organic analytes to alter electrical properties (
eg
, resistance or capacitance). Are [106-108]. The main problem with using conventional electrochemical sensors (
for example
, unmodified metal oxide sensors or conductive polymers) for
chemical
sensing has been the almost indistinguishable sensor responses among similar analytes. This is due to the nature of that particular type of sensor, which relies
primarily
on the physical absorption or nonspecific
chemical
interactions between
chemical
analytes and sensor receptors. Relying on physical absorption,
in most cases
, leads to poor selectivity of electrochemical sensors to target analytes
as well
as interference with ambient humidity, which
in particular
greatly
limits the
use
of such sensors.
In addition
, the fundamental deviation of the sensor response due to aging is a major challenge for the development of electrochemical sensors. [76]