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