| 1. |
- Enrico, Alessandro, et al.
(författare)
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Ultrafast Direct Writing of Polymers as a Simple Fabrication Method for Organic Electrochemical Transistors
- 2023
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Ingår i: 2023 22nd International Conference on Solid-State Sensors, Actuators and Microsystems, Transducers 2023. - : Institute of Electrical and Electronics Engineers Inc.. ; , s. 1543-1546
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Konferensbidrag (refereegranskat)abstract
- Organic ionic/electronic conductors (OMIECs) offer a promising alternative to metals and inorganic semiconductors for direct interfacing between human-made electronics and biological tissues. A device that takes advantage of the mixed ionic/electronic conductivity of OMIEC materials is the organic electrochemical transistor (OECT). High-density OECTs are typically fabricated using costly cleanroom-based lithography and complex lift-off processes. To simplify the fabrication of OECTs, we propose laser direct writing of conjugated polymers using a commercial two-photon polymerization 3D printer. Ultrafast laser direct writing allows single-digit micrometer resolution and high-speed processing, thereby enabling a cost-effective and simple fabrication process.
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| 2. |
- Shakya, Jyoti, et al.
(författare)
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2D MXene electrochemical transistors
- 2024
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Ingår i: Nanoscale. - 2040-3364 .- 2040-3372. ; 16:6, s. 2883-2893
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Tidskriftsartikel (refereegranskat)abstract
- The solid-state field-effect transistor, FET, and its theories were paramount in the discovery and studies of graphene. In the past two decades another transistor based on conducting polymers, called organic electrochemical transistor (ECT), has been developed and largely studied. The main difference between organic ECTs and FETs is the mode and extent of channel doping; while in FETs the channel only has surface doping through dipoles, the mixed ionic-electronic conductivity of the channel material in organic ECTs enables bulk electrochemical doping. As a result, organic ECTs maximize conductance modulation at the expense of speed. To date ECTs have been based on conducting polymers, but here we show that MXenes, a class of 2D materials beyond graphene, enable the realization of electrochemical transistors (ECTs). We show that the formulas for organic ECTs can be applied to these 2D ECTs and used to extract parameters like mobility. These MXene ECTs have high transconductance values but low on-off ratios. We further show that conductance switching data measured using ECT, in combination with other in situ-ex situ electrochemical measurements, is a powerful tool for correlating the change in conductance to that of the redox state, to our knowledge, this is the first report of this important correlation for MXene films. 2D ECTs can draw great inspiration and theoretical tools from the field of organic ECTs and have the potential to considerably extend the capabilities of transistors beyond those of conducting polymer ECTs, with added properties such as extreme heat resistance, tolerance for solvents, and higher conductivity for both electrons and ions than conducting polymers. Here we show that not only conducting polymers, but also 2D MXenes can be used as materials for electrochemical transistors ECTs. MXene extend the capabilities of ECTs with properties such as extreme heat resistance, and higher conductivity/speeds.
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| 3. |
- Zeglio, Erica, 1987-, et al.
(författare)
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Mixing Insulating Commodity Polymers with Semiconducting n-type Polymers Enables High-Performance Electrochemical Transistors
- 2024
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Ingår i: Advanced Materials. - 0935-9648 .- 1521-4095.
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Tidskriftsartikel (refereegranskat)abstract
- Diluting organic semiconductors with a host insulating polymer is used to increase the electronic mobility in organic electronic devices, such as thin film transistors, while considerably reducing material costs. In contrast to organic electronics, bioelectronic devices such as the organic electrochemical transistor (OECT) rely on both electronic and ionic mobility for efficient operation, making it challenging to integrate hydrophobic polymers as the predominant blend component. This work shows that diluting the n-type conjugated polymer p(N-T) with high molecular weight polystyrene (10 KDa) leads to OECTs with over three times better mobility-volumetric capacitance product (µC*) with respect to the pristine p(N-T) (from 4.3 to 13.4 F V−1 cm−1 s−1) while drastically decreasing the amount of conjugated polymer (six times less). This improvement in µC* is due to a dramatic increase in electronic mobility by two orders of magnitude, from 0.059 to 1.3 cm2 V−1 s−1 for p(N-T):Polystyrene 10 KDa 1:6. Moreover, devices made with this polymer blend show better stability, retaining 77% of the initial drain current after 60 minutes operation in contrast to 12% for pristine p(N-T). These results open a new generation of low-cost organic mixed ionic-electronic conductors where the bulk of the film is made by a commodity polymer.
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| 4. |
- Zeglio, Erica, 1987-
(författare)
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Self-doped Conjugated Polyelectrolytes for Bioelectronics Applications
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Self-doped conjugated polyelectrolytes (CPEs) are a class of conducting polymers constituted of a π-conjugated backbone and charged side groups. The ionic groups provide the counterions needed to balance the charged species formed in the CPEs backbones upon oxidation. As a result, addition of external counterions is not required, and the CPEs can be defined as selfdoped. The combination of their unique optical and electrical properties render them the perfect candidates for optoelectronic applications. Additionally, their “soft” nature provide for the mechanical compatibility necessary to interface with biological systems, rendering them promising materials for bioelectronics applications. CPEs solubility, aggregation state, and optoelectronic properties can be easily tuned by different means, such as blending or interaction with oppositely charged species (such as surfactants), in order to produce materials with the desired properties. In this thesis both the strategies have been explored to produce new functional materials that can be deposited to form a thin film and, therefore, used as an active layer in organic electrochemical transistors (OECTs). Microstructure formation of the films as well as influence on devices operation and performance have been investigated. We also show that these methods can be exploited to produce materials whose uniquecombination of self-doping ability and hydrophobicity allows incorporation into the phospholipid double layer of biomembranes, while retaining their properties. As a result, self-doped CPEs can be used both as sensing elements to probe the physical state of biomembranes, and as functional ones providing them with new functionalities, such as electrical conductivity. Integration of conductive electronic biomembranes into OECTs devices has brought us one step forward on the interface of manmade technologies with biological systems.
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