Investigation of ionic doping in all-solid-state organic electrochemical transistors
Organic electrochemical transistors (OECTs) represent a new generation of transistors based on the electrochemical doping of conjugated semiconductors, which possess attractive features such as high transconductance and low operation voltage compared to conventional field-effect transistors. Neve...
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sg-ntu-dr.10356-1738022024-03-07T08:52:06Z Investigation of ionic doping in all-solid-state organic electrochemical transistors Hou, Kunqi Lew Wen Siang School of Physical and Mathematical Sciences WenSiang@ntu.edu.sg Engineering Organic electrochemical transistor Solid electrolyte Ionic doping Organic electrochemical transistors (OECTs) represent a new generation of transistors based on the electrochemical doping of conjugated semiconductors, which possess attractive features such as high transconductance and low operation voltage compared to conventional field-effect transistors. Nevertheless, the utilization of liquid electrolytes in OECTs restricts their potential applications in wearable electronics due to stability and packaging issues. Consequently, the development of all-solid-state OECTs (SSOECTs) becomes imperative to enable stable operation and expand the application scenarios of OECTs beyond bioelectronics. In this thesis, an extensive investigation of ionic doping in all-solid-state OECTs is performed for addressing the stability and scalability challenges associated with the use of liquid electrolytes. Firstly, an electrochemical annealing effect is observed in Poly (3,4- ethylenedioxythiophene)-poly (styrene sulfonate) (PEDOT:PSS)-based SSOECTs, which induces a significant change in film microstructure and carrier transport mobility, resulting in enhancement of electrical performance and thermal stability of SSOECTs. Further, we proceed to develop a universal solid polymer electrolyte based on thermoplastic polyurethane (TPU) ionic gels and showed good OECT performance with four different ion-permeable semiconductors to prove the generality of the TPU solid electrolyte. It is found that the electrochemical doping ability of the electrolyte is influenced by the hydrophilicity/hydrophobicity of the ionic liquids used in the electrolyte for various types of conjugated polymers. These transistors are also found to be robust against a wide temperature range, retaining their functionality from -50 °C to 120 °C. To demonstrate the applications of the developed SSOECTs, ‘in-electrolyte computing’ capability of our SSOECTs are assessed through tuning the parameters of the ionic circuits, e.g., ionic resistance (Rb) and gate capacitance (Cg) It is found that the charging dynamics of SSOECTs is heavily influenced by the bulk resistance of the solid electrolyte, resulting in tunable device performance with varying gate-channel distance. A 12-channel SSOECT-based multiplexer platform is further demonstrated based on this concept. Additionally, tunable transistor performance is also realized by adjusting the gate capacitance, resulting in nonvolatile SSOECT-based synaptic devices by scaling down the gate geometry. These results demonstrate a promising candidate for the developed SSOECTs for the next generation of sensory data processing and communication systems. Doctor of Philosophy 2024-02-28T04:30:31Z 2024-02-28T04:30:31Z 2023 Thesis-Doctor of Philosophy Hou, K. (2023). Investigation of ionic doping in all-solid-state organic electrochemical transistors. Doctoral thesis, Nanyang Technological University, Singapore. https://hdl.handle.net/10356/173802 https://hdl.handle.net/10356/173802 10.32657/10356/173802 en RIE2020 ASTAR AME IAF-ICP (Grant No. I1801E0030) MOE2019-T2-2-106 MOE2019-T2-2- 066 IAF-ICP (No. I2201E0013) This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License (CC BY-NC 4.0). application/pdf Nanyang Technological University |
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Engineering Organic electrochemical transistor Solid electrolyte Ionic doping Hou, Kunqi Investigation of ionic doping in all-solid-state organic electrochemical transistors |
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Organic electrochemical transistors (OECTs) represent a new generation of transistors based
on the electrochemical doping of conjugated semiconductors, which possess attractive features
such as high transconductance and low operation voltage compared to conventional field-effect
transistors. Nevertheless, the utilization of liquid electrolytes in OECTs restricts their potential
applications in wearable electronics due to stability and packaging issues. Consequently, the
development of all-solid-state OECTs (SSOECTs) becomes imperative to enable stable
operation and expand the application scenarios of OECTs beyond bioelectronics.
In this thesis, an extensive investigation of ionic doping in all-solid-state OECTs is
performed for addressing the stability and scalability challenges associated with the use of
liquid electrolytes. Firstly, an electrochemical annealing effect is observed in Poly (3,4-
ethylenedioxythiophene)-poly (styrene sulfonate) (PEDOT:PSS)-based SSOECTs, which
induces a significant change in film microstructure and carrier transport mobility, resulting in
enhancement of electrical performance and thermal stability of SSOECTs. Further, we proceed
to develop a universal solid polymer electrolyte based on thermoplastic polyurethane (TPU)
ionic gels and showed good OECT performance with four different ion-permeable
semiconductors to prove the generality of the TPU solid electrolyte. It is found that the
electrochemical doping ability of the electrolyte is influenced by the
hydrophilicity/hydrophobicity of the ionic liquids used in the electrolyte for various types of
conjugated polymers. These transistors are also found to be robust against a wide temperature
range, retaining their functionality from -50 °C to 120 °C.
To demonstrate the applications of the developed SSOECTs, ‘in-electrolyte computing’
capability of our SSOECTs are assessed through tuning the parameters of the ionic circuits,
e.g., ionic resistance (Rb) and gate capacitance (Cg) It is found that the charging dynamics of
SSOECTs is heavily influenced by the bulk resistance of the solid electrolyte, resulting in
tunable device performance with varying gate-channel distance. A 12-channel SSOECT-based
multiplexer platform is further demonstrated based on this concept. Additionally, tunable
transistor performance is also realized by adjusting the gate capacitance, resulting in nonvolatile
SSOECT-based synaptic devices by scaling down the gate geometry. These results
demonstrate a promising candidate for the developed SSOECTs for the next generation of
sensory data processing and communication systems. |
author2 |
Lew Wen Siang |
author_facet |
Lew Wen Siang Hou, Kunqi |
format |
Thesis-Doctor of Philosophy |
author |
Hou, Kunqi |
author_sort |
Hou, Kunqi |
title |
Investigation of ionic doping in all-solid-state organic electrochemical transistors |
title_short |
Investigation of ionic doping in all-solid-state organic electrochemical transistors |
title_full |
Investigation of ionic doping in all-solid-state organic electrochemical transistors |
title_fullStr |
Investigation of ionic doping in all-solid-state organic electrochemical transistors |
title_full_unstemmed |
Investigation of ionic doping in all-solid-state organic electrochemical transistors |
title_sort |
investigation of ionic doping in all-solid-state organic electrochemical transistors |
publisher |
Nanyang Technological University |
publishDate |
2024 |
url |
https://hdl.handle.net/10356/173802 |
_version_ |
1794549448120991744 |