OFET sensors
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The document discusses Organic Field-Effect Transistor (OFET) sensors, highlighting their structure, working principles, and applications in various sensing fields including biosensors, chemical sensors, and explosive detection. It covers different organic materials used for the active layer, device configurations, and the potential advantages of OFET sensors such as biodegradability and flexibility. The conclusion emphasizes the need for further improvements in sensitivity, selectivity, and stability for practical applications.
![Introduction
Sensors
Transducer
Conversion into signals
Applications
[2]
Organic conducting polymers
Discovery [1]
Applications
Organic Thin Film Transistor (OTFT)
[1] H. Shirakawa et al. , “Synthesis of electrically conducting organic polymers: halogen derivatives of
polyacetylene, (ch),”, 1977
[2] P. Lin and F. Yan, “Organic thin-film transistors for chemical and biological sensing,” 2012
OFET Sensors : IIT Bombay
2](https://image.slidesharecdn.com/ofetsensors-131214075958-phpapp01/85/OFET-sensors-2-320.jpg)
![Device Structure & Working
OECT
Source & Drain electrodes
OSC channel
Electrolytic layer on top
OFET
Similar to OECT
Direct interaction with analyte
Two configurations
[1]
[1] P. Lin and F. Yan, “Organic thin-film transistors for chemical and biological sensing,”, 2012
OFET Sensors : IIT Bombay
4](https://image.slidesharecdn.com/ofetsensors-131214075958-phpapp01/85/OFET-sensors-4-320.jpg)
![OFETs in detail
Two configurations
Top contact
Bottom contact
Lower mobility in the channel
Follows standard MOSFET equations
[1]
[1] H. Ma, et al., “Multifunctional phosphoric acid self-assembled monolayers on metal oxides as
dielectrics, interface modification layers and semiconductors for low-voltage high-performance organic
field-effect transistors,”, 2012
OFET Sensors : IIT Bombay
5](https://image.slidesharecdn.com/ofetsensors-131214075958-phpapp01/85/OFET-sensors-5-320.jpg)
![Bio-sensors : DNA
[2]
Zhang et al. used pentacene as the OSC channel
DNA adsorption VT shift Electron extraction by DNA
Improvement suggestions
Reducing film thickness or
current
Increase substrate
temperature
[3]
Yan et al. proposed another device using P3HT
[2]
[1]
[1]http://www.intechopen.com/books/biosensors/design-and-fabrication-of-nanowire-basedconductance-biosensor-using-spacer-patterning-techniq
[2] Q. Zhang and V. Subramanian, 2012
[3] F. Yan, S. M. Mok, J. Yu, H. L. Chan, and M. Yang, 2009
OFET Sensors : IIT Bombay
7](https://image.slidesharecdn.com/ofetsensors-131214075958-phpapp01/85/OFET-sensors-7-320.jpg)
![Bio-sensors : Glucose & Others
[1]
J.Liu et al. proposed PEDOT-PSS organic channel with GOx
entrapped
GOx entrapped during polymerization
Redox reaction channel and glucose with Gox
catalysis
[2]
Sensor based on Ta2O5 and P3HT , by Bartic et al.
GOx anchored on surface
Cyanopropyltrichlorosilane treatment
[3]
Roberts et al. OFET to detect glucose, cystein, and MPA by
DDFTTF as the OSC channel
[1] J. Liu, M. Agarwal, and K. Varahramyan, “Glucose sensor based on organic thin film transistor using glucose
oxidase and conducting polymer,” , 2008
[2] C. Bartic, A. Campitelli, and S. Borghs, “Field-effect detection of chemical species with hybrid
organic/inorganic transistors,” , 2003
[3] M. E. Roberts, S. C. B. Mannsfeld, N. Queralt, C. Reese, J. Locklin, W. Knoll, and Z. Bao, “Water-stable organic
transistors and their application in chemical and biological sensors,”
OFET Sensors : IIT Bombay
8](https://image.slidesharecdn.com/ofetsensors-131214075958-phpapp01/85/OFET-sensors-8-320.jpg)
![Chemical Sensors : Ions & pH
[1]
Ji et al. P3HT as the OSC, with Ta2O5 and valinomycin
subsequently deposited on top
+ +
Detects K , H ions and pH levels
[2]
Scarpa et al. used P3HT as channel
+ +
2+
K , Na, Ca ions and pH levels even at 0.001%
[3]
Maddalena et al. had a sulfate receptor with incorporated
thiol group, coupled polystyrene layer
Detects sulphate ions with 1mM
[1] T. Ji, P. Rai, S. Jung, and V. K. Varadan, “In vitro evaluation of flexible ph and potassium ion-sensitive organic
field effect transistor sensors,” 2008
[2] G. Scarpa, A.-L. Idzko, A. Yadav, and S. Thalhammer, “Organic ISFET based on poly (3-hexylthiophene),” 2010
[3] F. Maddalena, M. J. Kuiper, B. Poolman, F. Brouwer, J. C. Hummelen, D. M. de Leeuw, B. De Boer, and
P. W. M. Blom, “Organic field-effect transistor-based biosensors functionalized with protein receptors,” , 2010
OFET Sensors : IIT Bombay
10](https://image.slidesharecdn.com/ofetsensors-131214075958-phpapp01/85/OFET-sensors-10-320.jpg)
![Chemical Sensors : Ions & pH
[1]
Bartic et al. reported a P3HT OSC OFET
Indicates the pH values after in-situ amplification
Coating with arachidic acid improves the sensitivity
[2]
Pentacene OSC based OFET proposed by Loi et al.
variations in charge at the gate-channel interface
coating the floating gate with thioaminic groups
Water stable OFET which can detect pH 3 to 11, using DFTTF
OSC channel by Roberts et al.[3]
[1] C. Bartic, A. Campitelli, and S. Borghs, “Field-effect detection of chemical species with hybrid
organic/inorganic transistors,” 2003
[2] A. Loi, I. Manunza, and A. Bonfiglio, “Flexible, organic, ion-sensitive field-effect transistor,” 2005
[3] M. E. Roberts, S. C. B. Mannsfeld, N. Queralt, C. Reese, J. Locklin, W. Knoll, and Z. Bao, “Water-stable organic
transistors and their application in chemical and biological sensors,” 2008
OFET Sensors : IIT Bombay
11](https://image.slidesharecdn.com/ofetsensors-131214075958-phpapp01/85/OFET-sensors-11-320.jpg)
![Gas Sensors
[1]
Laurs et al. observed that oxygen, iodine and bromine could
vary the current through the OFET fabricated with
phthalocyanines (Pcs) as the OSC.
[2]
Torsi et al. fabricated NTCDA
based OFET, and found four
characteristic parameters to
be varying.
[3]
[4]
Someya et al. and Torsi et al.
Reported the dependancy of
sensitivity on grain size.
[1] H. Laurs and G. Heiland, “Electrical and optical properties of phthalocyanine films,” 1987
[2] L. Torsi, A. Dodabalapur, L. Sabbatini, and P. Zambonin, “Multi-parameter gas sensors based on organic thinfilm-transistors,” 2000
[3] T. Someya, A. Dodabalapur, A. Gelperin, H. E. Katz, and Z. Bao, “Integration and response of organic
electronics with aqueous microfluidics,” 2002
[4] L. Torsi, A. J. Lovinger, B. Crone, T. Someya, A. Dodabalapur, H. E.Katz, and A. Gelperin, “Correlation between
oligothiophene thin film transistor morphology and vapor responses,” 2002
OFET Sensors : IIT Bombay
13](https://image.slidesharecdn.com/ofetsensors-131214075958-phpapp01/85/OFET-sensors-13-320.jpg)
![Explosive vapor sensor
A particular type of gas sensor
OFETs as explosive sensors
RDX
[1]
TNT
Materials proposed to be
used as OSC channel
Poly 3-hexylthiophene
(P3HT)
[2]
II
Cu tetraphenylpophyrin
(CuTPP)
[1] Ravishankar S. et al. “Explosive vapor sensor using poly 3-hexylthiophene and Cu tetraphenylporphyrin
composite based organic field effect transistors“ 2008
[2] http://www.aist.go.jp/aist_e/aist_laboratories/2information
OFET Sensors : IIT Bombay
15](https://image.slidesharecdn.com/ofetsensors-131214075958-phpapp01/85/OFET-sensors-15-320.jpg)
![Device structure and fabrication
[1]
SiO2 layer grown on n silicon wafer
Au / Ti Source & Drains are patterned
HMDS Surface enhancement
CuTPP & P3HT dissolved in chloroform is spin coated
[1] Ravishankar S. et al. “Explosive vapor sensor using poly 3-hexylthiophene and Cu tetraphenylporphyrin
composite based organic field effect transistors“ 2008
OFET Sensors : IIT Bombay
16](https://image.slidesharecdn.com/ofetsensors-131214075958-phpapp01/85/OFET-sensors-16-320.jpg)
OFET sensors
- 1. OFET Sensors Titto Thomas 133079015 M.Tech Seminar
- 2. Introduction Sensors Transducer Conversion into signals Applications [2] Organic conducting polymers Discovery [1] Applications Organic Thin Film Transistor (OTFT) [1] H. Shirakawa et al. , “Synthesis of electrically conducting organic polymers: halogen derivatives of polyacetylene, (ch),”, 1977 [2] P. Lin and F. Yan, “Organic thin-film transistors for chemical and biological sensing,” 2012 OFET Sensors : IIT Bombay 2
- 3. More about OTFTs Internal amplification and noise correction Compatibility with existing VLSI Technology Sensors could be Biodegradable Flexible Cost effective More information than any other sensor OTFT OFET Sensors : IIT Bombay OECT OFET 3
- 4. Device Structure & Working OECT Source & Drain electrodes OSC channel Electrolytic layer on top OFET Similar to OECT Direct interaction with analyte Two configurations [1] [1] P. Lin and F. Yan, “Organic thin-film transistors for chemical and biological sensing,”, 2012 OFET Sensors : IIT Bombay 4
- 5. OFETs in detail Two configurations Top contact Bottom contact Lower mobility in the channel Follows standard MOSFET equations [1] [1] H. Ma, et al., “Multifunctional phosphoric acid self-assembled monolayers on metal oxides as dielectrics, interface modification layers and semiconductors for low-voltage high-performance organic field-effect transistors,”, 2012 OFET Sensors : IIT Bombay 5
- 6. OFET Sensors in detail OFET Sensors Bio-Sensors DNA Proteins Glucose Others OFET Sensors : IIT Bombay Gas Sensors Chemical Sensors Ions Humidity Other sensors X-ray Others pH Others 6
- 7. Bio-sensors : DNA [2] Zhang et al. used pentacene as the OSC channel DNA adsorption VT shift Electron extraction by DNA Improvement suggestions Reducing film thickness or current Increase substrate temperature [3] Yan et al. proposed another device using P3HT [2] [1] [1]http://www.intechopen.com/books/biosensors/design-and-fabrication-of-nanowire-basedconductance-biosensor-using-spacer-patterning-techniq [2] Q. Zhang and V. Subramanian, 2012 [3] F. Yan, S. M. Mok, J. Yu, H. L. Chan, and M. Yang, 2009 OFET Sensors : IIT Bombay 7
- 8. Bio-sensors : Glucose & Others [1] J.Liu et al. proposed PEDOT-PSS organic channel with GOx entrapped GOx entrapped during polymerization Redox reaction channel and glucose with Gox catalysis [2] Sensor based on Ta2O5 and P3HT , by Bartic et al. GOx anchored on surface Cyanopropyltrichlorosilane treatment [3] Roberts et al. OFET to detect glucose, cystein, and MPA by DDFTTF as the OSC channel [1] J. Liu, M. Agarwal, and K. Varahramyan, “Glucose sensor based on organic thin film transistor using glucose oxidase and conducting polymer,” , 2008 [2] C. Bartic, A. Campitelli, and S. Borghs, “Field-effect detection of chemical species with hybrid organic/inorganic transistors,” , 2003 [3] M. E. Roberts, S. C. B. Mannsfeld, N. Queralt, C. Reese, J. Locklin, W. Knoll, and Z. Bao, “Water-stable organic transistors and their application in chemical and biological sensors,” OFET Sensors : IIT Bombay 8
- 9. Bio-sensors : Overview OFET Sensors : IIT Bombay 9
- 10. Chemical Sensors : Ions & pH [1] Ji et al. P3HT as the OSC, with Ta2O5 and valinomycin subsequently deposited on top + + Detects K , H ions and pH levels [2] Scarpa et al. used P3HT as channel + + 2+ K , Na, Ca ions and pH levels even at 0.001% [3] Maddalena et al. had a sulfate receptor with incorporated thiol group, coupled polystyrene layer Detects sulphate ions with 1mM [1] T. Ji, P. Rai, S. Jung, and V. K. Varadan, “In vitro evaluation of flexible ph and potassium ion-sensitive organic field effect transistor sensors,” 2008 [2] G. Scarpa, A.-L. Idzko, A. Yadav, and S. Thalhammer, “Organic ISFET based on poly (3-hexylthiophene),” 2010 [3] F. Maddalena, M. J. Kuiper, B. Poolman, F. Brouwer, J. C. Hummelen, D. M. de Leeuw, B. De Boer, and P. W. M. Blom, “Organic field-effect transistor-based biosensors functionalized with protein receptors,” , 2010 OFET Sensors : IIT Bombay 10
- 11. Chemical Sensors : Ions & pH [1] Bartic et al. reported a P3HT OSC OFET Indicates the pH values after in-situ amplification Coating with arachidic acid improves the sensitivity [2] Pentacene OSC based OFET proposed by Loi et al. variations in charge at the gate-channel interface coating the floating gate with thioaminic groups Water stable OFET which can detect pH 3 to 11, using DFTTF OSC channel by Roberts et al.[3] [1] C. Bartic, A. Campitelli, and S. Borghs, “Field-effect detection of chemical species with hybrid organic/inorganic transistors,” 2003 [2] A. Loi, I. Manunza, and A. Bonfiglio, “Flexible, organic, ion-sensitive field-effect transistor,” 2005 [3] M. E. Roberts, S. C. B. Mannsfeld, N. Queralt, C. Reese, J. Locklin, W. Knoll, and Z. Bao, “Water-stable organic transistors and their application in chemical and biological sensors,” 2008 OFET Sensors : IIT Bombay 11
- 12. Chemical sensors : Overview OFET Sensors : IIT Bombay 12
- 13. Gas Sensors [1] Laurs et al. observed that oxygen, iodine and bromine could vary the current through the OFET fabricated with phthalocyanines (Pcs) as the OSC. [2] Torsi et al. fabricated NTCDA based OFET, and found four characteristic parameters to be varying. [3] [4] Someya et al. and Torsi et al. Reported the dependancy of sensitivity on grain size. [1] H. Laurs and G. Heiland, “Electrical and optical properties of phthalocyanine films,” 1987 [2] L. Torsi, A. Dodabalapur, L. Sabbatini, and P. Zambonin, “Multi-parameter gas sensors based on organic thinfilm-transistors,” 2000 [3] T. Someya, A. Dodabalapur, A. Gelperin, H. E. Katz, and Z. Bao, “Integration and response of organic electronics with aqueous microfluidics,” 2002 [4] L. Torsi, A. J. Lovinger, B. Crone, T. Someya, A. Dodabalapur, H. E.Katz, and A. Gelperin, “Correlation between oligothiophene thin film transistor morphology and vapor responses,” 2002 OFET Sensors : IIT Bombay 13
- 14. Gas sensors : overview OFET Sensors : IIT Bombay 14
- 15. Explosive vapor sensor A particular type of gas sensor OFETs as explosive sensors RDX [1] TNT Materials proposed to be used as OSC channel Poly 3-hexylthiophene (P3HT) [2] II Cu tetraphenylpophyrin (CuTPP) [1] Ravishankar S. et al. “Explosive vapor sensor using poly 3-hexylthiophene and Cu tetraphenylporphyrin composite based organic field effect transistors“ 2008 [2] http://www.aist.go.jp/aist_e/aist_laboratories/2information OFET Sensors : IIT Bombay 15
- 16. Device structure and fabrication [1] SiO2 layer grown on n silicon wafer Au / Ti Source & Drains are patterned HMDS Surface enhancement CuTPP & P3HT dissolved in chloroform is spin coated [1] Ravishankar S. et al. “Explosive vapor sensor using poly 3-hexylthiophene and Cu tetraphenylporphyrin composite based organic field effect transistors“ 2008 OFET Sensors : IIT Bombay 16
- 17. Device Characterization Significant rise in drain current & conductance in the presence of nitro compounds Threshold voltage is found out by linear fit of Transfer Chara Behavior can be modeled by using existing equations Shift in FTIR peaks on sensor exposure to RDX OFET Sensors : IIT Bombay 17
- 18. OFET explosive vapor sensor : Results & Conclusion Selectivity of the sensor for various vapors The OFET formed has high sensitivity to nitro based explosives ION & S parameters can be evaluated to check the presence OFET Sensors : IIT Bombay 18
- 19. Conclusions & Future Scope OFETs are effective sensors for detecting various types of materials Many materials being tried out to be used in sensors have a promising performance Also there is a need for new structures and modifications to enhance the sensing abilities of sensors Sensitivity, selectivity, stability all have to be improved before using them in real life applications OFET Sensors : IIT Bombay 19
- 20. Thank You OFET Sensors : IIT Bombay 20