25th Anniversary Article: Key Points for High‐Mobility Organic Field‐Effect Transistors

Abstract

Remarkable progress has been made in developing high performance organic field-effect transistors (OFETs) and the mobility of OFETs has been approaching the values of polycrystalline silicon, meeting the requirements of various electronic applications from electronic papers to integrated circuits. In this review, the key points for development of high mobility OFETs are highlighted from aspects of molecular engineering, process engineering and interface engineering. The importance of other factors, such as impurities and testing conditions is also addressed. Finally, the current challenges in this field for practical applications of OFETs are further discussed.

Solution‐Processed Bilayer Dielectrics for Flexible Low‐Voltage Organic Field‐Effect Transistors in Pressure‐Sensing Applications

“…Among them, transistor‐based sensors usually perform pressure detection via a capacitance mechanism, where a tiny change in capacitance under tactile stimuli will produce a large current signal 13. As an emerging element in flexible electronic devices, organic field‐effect transistors (OFETs) have distinguished functions such as signal transduction and amplification 14, 15. At the same time, they are light in weight, flexible, and can be manufactured economically on plastic substrates by large‐area solution processing 16, 17.…”

Small Molecule/Polymer Blend Organic Transistors with Hole Mobility Exceeding 13 cm2 V−1 s−1

“…[1] [2] The desire for roll-to-roll printed, transparent, flexible electronics with greater economic viability has driven extensive research in the field, leading to substantial advances in the electronic properties of organic materials. These developments are illustrated by the overall rise in charge carrier mobilities -a crucial figure of merit -in organic thin-film transistors (OTFTs).…”

Contactless charge carrier mobility measurement in organic field-effect transistors

“…The performance of organic field-effect transistors (OFET) increases remarkably, and an increasing number of organic semiconductors is being reported with a charge carrier mobility over that of a-Si, $1 cm 2 /V s [1,2]. Especially n-type and ambipolar polymers recently made strong progression [3][4][5][6][7][8].…”

“…Especially n-type and ambipolar polymers recently made strong progression [3][4][5][6][7][8]. However, as the channel resistance decreases due to the increase of organic semiconductor mobilities, contact resistances often become the bottleneck for the total device performance [1,9,10]. Many strategies have been reported to decrease the contact resistance for either holes or electrons [1,10,11], using selfassembled monolayers [12,13], doping [14,15], interlayers [16,17], or by changing the device lay-out [9,18].…”

“…However, as the channel resistance decreases due to the increase of organic semiconductor mobilities, contact resistances often become the bottleneck for the total device performance [1,9,10]. Many strategies have been reported to decrease the contact resistance for either holes or electrons [1,10,11], using selfassembled monolayers [12,13], doping [14,15], interlayers [16,17], or by changing the device lay-out [9,18]. Contact resistance is an (even) more fundamental problem in ambipolar transistors, where both electrons and holes need to be injected [5,19].…”