Biomedical Engineering Reference
In-Depth Information
Pt
SWCNT
Resistor
CO
DL: 1 ppm CO
CR: 1-10 ppm CO
OT: RT
[236]
Au, Ag
MWCNT
Resistor
NO
DL: 500 ppb NO
[235]
2
2
OT: RT
Rst: <2 min
Au, Pt
MWCNT
Resistor
NO
, NH
DL: 100 ppb NO
[246]
2
3
2
DL: 5 ppm NH
3
OT: 150°C
Rst: <2 min
Pt, Pd
MWCNT
Resistor
NO
, H
S, NH
,
DL: 100 ppb NO
[247]
2
2
3
2
CR: 5-1000 ppm NH
CO
3
CR: 0.1-10 ppm H
S
2
OT: 200°C
Rst: <10 min
Au
MWCNT
Resistor
NO
, H
S, NH
,
DL: 100 ppb NO
[248]
2
2
3
2
CO, SO
, N
O
OT: 20-250°C
Rst: <4 min
2
2
Au
MWCNT
Amperom
Acetylene
Sensitivity: 80 nA/
ppm
RC: 10-50 ppm
Linearity: 1-28 mM
[240]
Pt
MWCNT
Amperom
Glucose
Sens.: 52.7 (
µ
A/cm
2
)/
[239]
mM
Rst: 25 s (50 ppm)
DL = detection limit; S = sensitivity; CR = concentration range; Rst = response time;
Rct = recovery time; OT = operating temperature.
9.5
Transducers Using Carbon Nanotubes
A gas sensor combines a transducer and a gas-sensitive material that
is responsible for gas adsorption, thus sensitivity. Selective coatings
must be engineered and fabricated for high performance of sensing
devices as well. Typically, sensor materials are very important for gas
detection as chemical interface, but transducer is also strategic for
advanced gas sensors in order to transduce the chemical information
captured by sensor material into a measurable sensor response for
signal processing.
Various principles of transduction can be used for gas sensors: the
electrical charge transfer in the chemiresitors; the chemical gating
electrically induced and modulated in the FET; the amperometric,
voltammetric, and potentiometric effects in the electrochemical
