Synthetic chemistry for ultrapure, processable, and high mobility organic transistor semiconductors

There is growing recognition of the opportunity to fabricate low-cost and/or large-area electronic components from organic-based circuits. Such circuits are not predicted to replace silicon technology where high device density, speed, and stability under extreme conditions are vital. Rather, they may play a role in applications such as identification tags, smart cards, and display drivers that re intended for single or short-term use, very large-scale manufacture, low resolution architectures, or plastic substrates. The main logic units in these circuits are field-effect transistors (FETs), comprising a gate electrode, gate dielectric, semiconductor, and source/drain electrodes. The device is generally in an insulating state until a gate voltage is applied (relative to the source), which establishes a "channel" of charge at the semiconductor-dielectric interface, turns the device on and allows conductivity between the source and drain. (Figure 1) (Other conceivable active organic electronic devices include rectifiers, photoconductors, photovoltaics, and the commercially important light-emitting diodes, which are outside the scope of this manuscript.) In keeping with the goal of low cost processing, all of the elements of the FET must be deposited and patterned using techniques such as printing, stamping, casting, and rapid sublimation or thermal transfer. This is in contrast to the much more capital-intensive processes associated with patterning and deposition on silicon, and the subsequent interconnection and packaging.