The field of organic electronics has seen significant growth over the past decade, driven by advances in high-performance organic semiconductors (OSCs), large-scale fabrication techniques, and a deeper understanding of operation mechanisms. One area where this growth has been particularly notable is in the development of flexible electronic interfaces for sensing applications.

At the heart of these interfaces are organic thin film transistors (OTFTs), which have been demonstrated as the primary building blocks of various devices such as low-cost radio-frequency identification tags, flexible displays, wearable sensors, medical devices, digital and analog circuits. Complementary circuits, wireless systems, memory and processing units have all been successfully implemented using OTFTs, paving the way for their potential use in a wide range of sensing applications.

One key component of these interfaces is the transistor amplifier, which plays a crucial role in amplifying weak signals to make them detectable by sensors. In this context, the development of high-performance OTFTs with flexible electrodes is essential. For example, bottom contact TFTs with polymeric PANi-PSS electrodes have been shown to exhibit superior electrical characteristics compared to those with conventional metal electrodes, due to a lower charge injection barrier and resultant lower contact resistance.

In one recent study, researchers demonstrated the use of single-stage differential amplifier realized with p-type Pentacene transistors with mobility, 0.5 cm 2/Vs, which exhibited a voltage gain of 10 dB in a frequency bandwidth of 1 kHz. The measurement of transistor characteristics and amplifier response was carried out using a wafer probing test jig set up.

The development of OTFTs with flexible electrodes is crucial for the realization of flexible electronic interfaces for sensing applications. In this regard, researchers have successfully fabricated OTFTs using thermally evaporated Pentacene as the semiconducting layer, and realized the electrodes using a conductive polymer composite, poyaniline:polystyrene sulphonic acid (PANi-PSS), patterned by a modified Parylene lift-off process.

In summary, the development of high-performance OTFTs with flexible electrodes is essential for realizing flexible electronic interfaces for sensing applications. The demonstration of single-stage differential amplifier using OTFTs has shown promising results in terms of voltage gain and frequency bandwidth, highlighting their potential use in amplifying weak signals to make them detectable by sensors.

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