Organic field-effect transistors based on tetrathiafulvalene derivatives*

In recent years, tetrathiafulvalene (TTF) and its derivatives have been used as semiconducting materials for organic field-effect transistors (OFETs). In this review, we summarize the recent progress in the field of TTF-based OFETs. We introduce the structure and operation of OFETs, and focus on TTF derivatives used in OFETs. TTF derivatives used in OFETs can be divided into three parts by the semiconductor’s morphology and the device fabrication technique: (1) TTF derivatives used for single-crystal OFETs, (2) TTF derivatives used for vacuum-deposited thin-film OFETs, and (3) TTF derivatives used for solutionprocessed thin-film OFETs. The single-crystal OFETs based on TTF derivatives were fabricated by drop-casting method and showed high performance, with the mobility up to 1.4 cm2/Vs. The vacuum-deposited thin-film OFETs based on TTF derivatives were well developed, some of which have shown high performance comparable to that of amorphous silicon, with good air-stability. Although the mobilities of most solution-processed OFETs based on TTF derivatives are limited at 10–2 cm2/Vs, the study on solution-processable TTF derivatives and their devices are promising, because of their low-cost, large-area-coverage virtues. The use of organic charge-transfer (OCT) compounds containing TTF or its derivatives in OFETs is also included in this review.