This article reviews recent major progress in the development of organic semiconductors as electron transport n-channel materials in organic field effect transistors (OFETs).

New phosphine-based ligands and DFT calculations for defect-free conjugated polymers by direct (hetero)arylation polymerization (DHAP).

Three thiophene-S,S-dioxidized indophenine (IDTO) isomers, 3 a (E,E,E), 3 b (Z,E,E), and 3 c (Z,E,Z), were synthesized by oxidation of an indophenine compound. 3 b and 3 c could be converted into the most-stable 3 a by heating at 110 °C. An IDTO-containing conjugated polymer, PIDTOTT, was prepared using 3 a as a comonomer through a Stille coupling reaction, and it possesses a narrow band gap and low energy levels. In organic field effect transistors (OFETs), PIDTOTT exhibited unipolar n-type semiconductor characteristics with unexpectedly high electron mobility (up to 0.14 cm(2)  V(-1)  s(-1)), despite its rather disordered chain packing.

Indigo is used as an electron acceptor for constructing polymer semiconductors that show n-channel behaviour in organic thin film transistors.