Soluble organic semiconductors used to print field effect transistors and electrochemical
thin film electronic components. In addition, a number of optical and opto-electronic device application exist such as light-emitting diodes LEDs
, photovoltaic and photoconductive devices, field-effect optical modulator devices and all-optical modulator devices made from thiophenes. There is strong commercial interest and research activity into organic semiconductors with the development of conducting and semiconducting conjugated polymers
. These offer scope for preparing large area conducting films for lightweight conductors, electromagnetic
shielding and large area semiconducting films for displays, solar cells and transistor arrays. Oligo(thiophene)s can be viewed both as materials with great potential for devices, partly because of their high field-effect mobilities, and also as finite model systems for the poly(thiophene)s.
Conjugated polymers have been widely studied as potential semiconductor materials for organic thin-film transistors (TFTs). However, they have provided functionally poor transistor properties when the TFTs are fabricated in air. . Professor Beng Ong and his team at Xerox have developed a class of liquid crystalline regioregular polythiophenes, PQTs, that possess sufficient air stability to enable achievement of excellent TFT properties under ambient conditions. These polythiophenes exhibit unique self-assembly ability and form highly structured thin films when deposited from solution under appropriate conditions. TFTs fabricated in air with PQT channel layers have provided high field-effect mobility to 0.14 cm2 V-1 s-1 and high current modulation to over 107, together with other desirable transistor properties. These high-performance polythiophenes will therefore help bring the long-standing concept of low-cost organic/polymer transistor circuits closer to commercial reality.