Multimodal Carbon Nanotube-based Sensors with Tunable
Sensitivity for Nitric Oxide and Carbon Monoxide DetectionLisa Je1, Suchol Savagatrup2, Maggie He3, Timothy Swager4
1Department of Chemistry, Vassar College, Poughkeepsie, NY1Department of Engineering, Dartmouth College Thayer School of Engineering, Hanover, NH; Dual Degree
2,3,4Department of Chemistry, Massachusetts Institute of Technology (MIT), Cambridge, MA.
• The National Science Foundation (NSF Award ECCS-
0939514)
• The Center for Energy Efficient Electronics Science
(E3S) at The University of California, Berkeley
• The Massachusetts Institute of Technology Summer
Research Program (MIT-SRP)
• Vassar College Tananbaum Leaders Fellowship
• Furthermore, Je. L is grateful for the guidance of Prof.
Timothy M. Swager, Dr. Suchol Savagatrup,
Dr. Maggie He, and the Swager group for support.
ConclusionsFabrication SensingIntroduction
Synthesis of Ligands
Carbon Nanotube Functionalization
Carbon Nanotube Characterization
• Organic syntheses of iodonium salts as ligands
for SWCNTs functionalization
• All ligands were functionalized according to the
iodonium method in Chem Matter., 2016; 28 (23)
8542-8549
Acknowledgements
Objectives & Motivations
Hypothesis
Experimental Methods
Future Work & Implications
• Detecting gases such as nitric oxide (NO) and
carbon monoxide (CO) is important for monitoring
their influences on human & environmental health
https://www.sciencetopia.net/pollution/air
https://www.senatorwindows.ie/2016/05/carbon
-monoxide-poisoning-the-silent-killer/
NO Detection Cu(II) CO Detection Cu(I)
Angew. Chem. Int. Ed. 1999, 38, 1865-1868
Murad F.
• Apparatus for FET sensing
- Mass Flow Controllers (MFC): gas flow [Yellow]
- MUX: translates gas sensing into current [Blue]
- Sensing Chamber: gas reaction enclosure [Red]
• FET fabrication process
1. Clean substrate (channels)
2. Drop cast SWCNTs in solvent
3. Copper complex infusion in solvent
An example of a finished
FET substrate
• We hypothesize that the FET gate voltage can
be manipulated to switch the oxidation state of
copper (Cu) on the functionalized SWCNTs to
selectively sense NO and CO.
• NO will bind to the sensor at the Cu (II) state and
CO to Cu (I) state.
• CuClO4 is a better selector than CuCl2• Functionalized-1 (F-1) SWCNTs tested better than
Pristine SWCNTs
• Vg = 3V, -3V appears to be worse than Vg = 0V
• Highest sensitivity so far is F1-SWCNT with
CuClO4 with Vg=0V at (ΔG/G0) 15-20%
• Non-reversible with CuClO4
• Successful in F-1, F-2, and F-3 synthesis
• Voltage modulation at different values [-5,5V]
• Different weak coordinating ions as selector
• CO sensing
• Complete F-4 synthesis
• These key findings are the basic architectures
for future Vg modulation in FET gaseous sensing
for higher induced current (ΔG/G0) signal
Raman
Spectroscopy
X-Ray
Photoelectron
Spectroscopy(XPS)
Thermogravimetric
Analysis (TGA)
3-phenanthroline iodonium salt (F-3)
2-bipyridine iodonium salt (F-1)
3-bipyridine iodonium salt (F-2)
A functionalized SWCNT
• We will develop a field-effect transistor (FET)
single wall carbon nanotube (SWCNT) based
chemical sensor to sense NO and CO via the
modulation of the transistor’s gate and drain voltage
An electrical schematic of a FET substrate channel
• The proposed device’s architecture will aid in the
development of future selective sensors due to the
comparable size and compatibility between other
nanoelectronics and biological nano-assemblies
• Main findings include the devices responding
to NO and CO gases with a substantial induced
current (ΔG/G0) signal
A visual model of a FET channel
Performance of SWCNTs in Ten Different Parameters First Exposures
Summary Statements
P-SWCNT
F-1-SWCNT
Legend
Main Findings
2. F-1
SWCNTs
gate voltage
modulation of
-3V and 3V
appear to
give a lower
induced
signal current
than 0 Vg
1. F-1
SWCNTs
appear to
have
higher
induced
current
signal
compared
to Pristine
SWCNTs
F-1 versus Pristine SWCNTs with CuClO4
F-1 SWCNTs gate voltage modulation with CuClO4