(up to 10 cm²/V⋅s) [7–9]. Singh et al. prepared a novel printed high-performance OTFT

using a polymer blend of 2,7-dihexyl-dithieno[2,3-d;2′,3′-d′]benzo[1,2-b;4,5-b′]dithiophene

(DTBDT-C6) and polystyrene (PS) [10]. Previous studies highlighted that it’s a major

strategy to prepare a uniform material on a substrate by simple and low-cost solution-

process methods using a solution with a low viscosity. To overcome the dewetting lim­

itation and prepare high-performance nanostructures with unique surface properties and

large surface areas enhancing electrochemical properties of materials for efficient charge

transport. In literature, Shen et al. developed green high-performance OFET using a blend

of 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C8-BTBT) and polymer binder based

thin films for flexible and printed electronic devices. Experimental results showed that the

proposed bio-based transistors use a blend of C8-BTBT and PS with a high stability and

mobility up to 6.80 cm²/Vs. It was clear that these excellent properties were related to large

domain sizes, smooth grain boundaries, and phase-separated [11]. Furthermore, OFETs

have been categorized into two types of approaches. Accordingly, they are grouped into

top-down and bottom-up methods, depending on either the bulk or nanomaterial structure

of the initial material [12]. As known, the typical design of an OFETs consists of the drain,

gate, metallic source, organic semiconductor, and electrolyte [13]. In Figure 10.1, schematic

diagrams of the bottom gate bottom contact, bottom gate top contact, top gate bottom

contact, and top gate top contact of OFETs are presented.

Three-dimensional (3D) printing is a low-cost and simple technique based on the cu­

mulation of thin layers of structures with a 3D digital type of material. As known, green

organic materials have a high solubility, high-quality support, and ease of use for un­

masked patterns in a single 3D application for advanced device fabrication. In the re­

search study of Fan et al. in 2019 [14], they developed a novel 3D-printed functional

organic electrochemical transistors by a polymer blend of PEDOT:PSS as a channel ma­

terial and silver as a source/drain for wearable and stand-alone biosensing applications.

The prepared organic electrochemical transistors based device showed good stability,

high electrical conductivity, high transconductance, low operating voltage, and high

current ON/OFF ratio in the voltage range of 0.66 ± 0.01 V. In another study, Majak et al.

in 2019 [15], fabricated a fully 3D-printed inverter logic gate sensor-based using a

FIGURE 10.1

Schematic diagrams of (a) bottom gate top contact, (b) bottom gate bottom contact, (c) top gate top contact, and

(d) top gate bottom contact of OFETs.

Organic Transistors

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