Ting Gao Group meeting May 2004 Novel Chemiresistors Approaches.

Ting Gao

Group meeting May 2004

Novel Chemiresistors Approaches

Monitor Swelling Induced Resistance Increases

Time

Res

ista

nce

R

Rmax

Rbaseline

Insulating Polymer/Carbon Black Sensors: How It Works

e-

e-

Analyte

Response of sensor isdescribed as Rmax/Rb

Array Response

SensorArray

∆R / R

Time

∆R

Glass substrate

Polymer/ Carbon Black Solution

gap

Sensor #

e -2 e -Ec/KT

: core-core seperation : ~ 1 År : the relative permittivity of the dielectric medium between the coresEc: the activation energy, essentially the Coulomb energy associated with charging two neutral particles and inversely proportional to the relative permittivity of the dielectric media

R/R ~ e -2-1If Ec/KT doesn’t change, ~ 0.2 Å results in 50% R/R changes.

Resistance between the gold nanocrystals

~~~~~~~~~~~~~~~

HAuCl4 (H2O) + RSH(Toluene) Au-SR(Toluene) NaBH4

(C8H17)4NBr

Preparation of Thiol Capped Gold Nanocrystals

H

ON

Organic Ligand capped TiO2-CB as Chemiresistors

Ti(O-isoPropoxide)4 + 4 H2O TiO2 + 4C2H5OHH+

OHHO

HO OH

OH

HO OH

OH

RCOOHOORROO

ROO OOR

OOR

ROO OOR

OOR

e-

e-

Analyte

6100

6120

6140

6160

6180

6200

6220

6240

6260

6280

3900 4400 4900 5400

47800

47850

47900

47950

48000

48050

48100

48150

48200

3900 4400 4900 5400

4660000

4670000

4680000

4690000

4700000

4710000

4720000

4730000

3900 4400 4900 5400

99800

100000

100200

100400

100600

100800

101000

101200

101400

101600

101800

102000

3900 4400 4900 5400

PEOTiO2 + dye

TiO2 +C15COOHAu-S-C8

S/N 217.2643 2.4588 17.2612 18.4464 /R R 0.0230 0.0050 0.0013 0.0092

Resistance Response to Eight Analytes TestedR

/R

Time (S)

Analytes from left to right:HexaneTHFEthanolEthyl AcetateCyclohexaneHeptaneN-octaneIso-octane

Time (s)

R

()

Third Try of TiO2 + Ligand C15COOH

-0.00020

0.00020.00040.00060.00080.001

0.00120.00140.00160.0018

0 500 1000 1500R

/R

Exposure Numbers

0

0.0002

0.0004

0.0006

0.0008

0.001

0.0012

0.0014

0.0016

0.0018

0 50 100 150 200

Series1

Series2

Series3

Series4

Series5

Series6

Series7

Third Try of TiO2 + Ligand C15COOH

R/R

Exposure Numbers along Time Scale

N C8H17C8H17

C8H17

C8H17

+

Br-

OH

O

OH

O

OH

O

O

O

HO

HOOH

BrBr

Br BrBrBr

H

Cl

N O

N

HO

HOOH

N+

O O-

C6H4-1,2,-[CO2CH2CH(C2H5)(CH2)3CH3]2

Monomers Tried in This Test

Cellulose PEVA PEO Au-S-C8 Au-S-C2-Ph Au-S-C3 Au-S-C12/CB Au-S-C16/CBRb 52201.2355 25772.427 144102.386 5648.21591 17151.0538 45795.6152 400086.915 1575606.67R 52287.2649 25872.7741 144268.358 5663.819 17189.3001 46381.4784 404107.443 1588298.1R-Rb 86.0294505 100.347075 165.972059 15.6030903 38.246343 585.863225 4020.52818 12691.425stdev(Rb) 3.0415208 5.55445059 10.9419545 0.03716976 0.24526122 5.17490084 8.53526262 331.319398S/N 9.42833714 6.02202222 5.05613688 139.926388 51.9804186 37.7374847 157.016382 12.7685703DR/R 0.00164803 0.00389358 0.00115176 0.00276248 0.00222997 0.012793 0.01004914 0.00805494

(C8H17)4NBr (C8H17)4NBr add Plastisizer C11COOH C11COOH add plastisizerRb 2215429.85 10271833.8 1615589.94 346925.479 1501.21855 1581.89234 65131.6519 72720.8782R 2179965.74 10305545.7 1621236.13 350094.581 1503.12578 1584.15409 65333.9202 72958.589R-Rb -35464.1059 33711.9053 5646.18286 3169.10148 1.90722363 2.26174715 202.268267 237.710756stdev(Rb) 5448.48499 14782.5365 794.936074 69.798494 0.04942321 0.04987837 16.7028461 10.6041284S/N -2.1696616 0.76017412 2.36756264 15.1345266 12.8632114 15.1150833 4.03660282 7.47227076DR/R -0.01600778 0.00328198 0.00349481 0.00913482 0.00127045 0.00142977 0.00310553 0.00326881

C23COOH C23COOH add plastisizer 3-methyl-2-phenylvaleric acidRb 28443.1759 31842.188 906994.848 261927.352 1387.66856 1719.9211R 28502.2158 31917.8798 917641.267 265369.113 1391.11558 1726.1754R-Rb 59.0399269 75.6917967 10646.419 3441.76173 3.44702109 6.25429701stdev(Rb) 3.55993522 4.17202053 460.295663 105.300015 0.03434286 0.07947505S/N 5.52818365 6.04757305 7.70984092 10.8950973 33.4569408 26.2316997DR/R 0.00207572 0.00237709 0.01173813 0.01314014 0.00248404 0.00363639

Comparison of Monomer and Polymer to Hexane

Comparison of Monomer and Polymer to Hexane Cellulose PEVA PEO

S/N 9.4283 6.022 5.056R/R 0.0016 0.004 0.001

(C8H17)4NBr add PlastisizerS/N -2.17 0.76 2.368 15.13R/R -0.016 0.003 0.003 0.009

C23COOH add plastisizerS/N 5.5282 6.048 7.71 10.9R/R 0.0021 0.002 0.012 0.013

C11COOH add plastisizerS/N 12.863 15.12 4.037 7.472R/R 0.0013 0.001 0.003 0.003

3-methyl-2-phenylvaleric acidS/N 33.457 26.23R/R 0.0025 0.004

Gold-S- C8 C2Ph C3 C12/CB C16/CBS/N 139.93 51.98 37.74 157 12.77R/R 0.0028 0.002 0.013 0.01 0.008

OH

O

Proposed Mechanism for Better Sensors

Free space

-0.0002

0.0003

0.0008

0.0013

0.0018

0 100 200

Time (s)

R/R

C24H50/Plastisizer to n-Hexane

-1.0E-04

1.0E-04

3.0E-04

5.0E-04

7.0E-04

9.0E-04

0 50 100 150 200

Series1

Series4

Series6

C20H42

C24H50

C30H62

Time (s)R

/R

Response of Several Monomer/CB to Hexane

Response of Several Monomer/CB to Hexane

-1.0E-04

1.0E-04

3.0E-04

5.0E-04

7.0E-04

9.0E-04

0 50 100 150 200

Series1

Series4

Series6

C20H42

C24H50

C30H62

Time (s)

R/R

C20H42/P

C24H50/P

C30H62/P

Time (s)R

/R

Reproducibility of a Typical Monomer/CB to Analytes

7244

7246

7248

7250

7252

7254

7256

7258

7260

7262

217000 218000 219000 220000 221000 222000 223000

Time (S)

R (

)

C24H50/Plastisizer to analytes.

Analytes from left to right: 6,6,5,4,7,5,7,1,1,4,5,1,5,5,8,1,8,7,8,4,6,7,7,3,8,5


39880

39900

39920

39940

39960

39980

40000

217000 218000 219000 220000 221000 222000 223000

Time (S)

O

O

HO

HOOH


R (

)


Time (S)


50940

50960

50980

51000

51020

51040

51060

51080

51100

51120

217000 218000 219000 220000 221000 222000 223000

H

Cl

N O

N

R (

)

Dose Response to Hexane

0

0.020.04

0.06

0.080.1

0.12

0.14

0.160.18

0.2

0 0.05 0.1 0.15 0.2

Series1Series2Series3Series4Series5Series6Series7Series8Series9

P/Po

R/

RC20H42

C20H42/PC24H50

C24H50/PC30H62

C30H62/PC10H12O5

C4H9O5

C4H9NO5

Dose Response to Ethanol

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0 0.05 0.1 0.15 0.2


P/Po

R/

RC20H42

C20H42/PC24H50

C24H50/PC30H62

C30H62/PC10H12O5

C4H9O5

C4H9NO5

Dose Response to Butylamine

C20H42

C20H42/PC24H50

C24H50/PC30H62

C30H62/PC10H12O5

C4H9O5

C4H9NO50

0.51

1.5

22.5

3

3.5

44.5

5

0 0.01 0.02 0.03


P/Po

R/

R

Experimental Setup

gas mixer

multimeter

air

air

sens

or

cham

ber

analyte: 1 2 3 … 8

MFC

MFC

0 200 400 600 800 1000

Time (s)

conc

entr

atio

n

Analyte chosen in random order

All the concentrations were controlled at 0.5% P/Po

Stability of a Typical Monomer/CB to Analytes

Exposure numbers along Time scale

R/R

0

0.001

0.002

0.003

0.004

0.005

0.006

0.007

0.008

0.009

0.01

0 50 100 150 200

N C8H17C8H17

C8H17

C8H17

+

Br-

with plastisizer



R/R

C24H50 with plastisizer

0

0.0005

0.001

0.0015

0.002

0.0025

0 50 100 150 200



R/R

C30H62

-0.0002

0

0.0002

0.0004

0.0006

0.0008

0.001

0.0012

0 50 100 150 200



R/R

-0.001

-0.0005

0

0.0005

0.001

0.0015

0.002

0.0025

0.003

0.0035

0 50 100 150 200

O

O

HO

HOOH

3-D Pattern of the Sensor Array to the Analytes

0

0.001

0.002

0.003

0.004

0.005

0.006

0.007

0.008

sensorsanalytes

R

/R

Principal Components Analysis Plot of the R/Rb Response of the Detector Array

Conclusions

Ligands capped TiO2 nanocrystals with carbon black composites are promising chemical vapor sensors.

Using monomers mixed with carbon black can easily make an sensor arrays with fast response time, good reproducibility and stability, better diversity, and having the ability to classify and identify vapors.

Additional tips:High density functional groupMore environmental friendlyFun

Acknowledgements

Prof. Nathan S. LewisBrian SiskLewis’ Group

TiO2:Don, Bruce, Jordon and Tony

$$$ NIH

Ting Gao Group meeting May 2004 Novel Chemiresistors Approaches.

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