A donor–acceptor–donor (D–A–D) type small molecule DHB-QDTB, with dicyano-substituted quinoidal benzo[1,2-b:4,5-b′]dithiophene as the acceptor, was designed and synthesized. A high electron mobility up to 0.88 cm2 V−1 s−1 was observed for DHB-QDTB based transistors under ambient conditions, suggesting quinoidal benzo[1,2-b:4,5-b′]dithiophene is an excellent acceptor unit in D–A type n-channel organic semiconductors.

Three regioisomeric sulfur-bridged pyrene–thienoacenes (PTAs) have been synthesized. The crystal structures and optoelectronic properties of these ring-fused PTAs and their ring-opened precursors have been fully investigated. Among these isomers, the [3,4]-extended compound (4-S-PTA) shows the most pronounced spectral red-shift and highest quantum yield as well as large transistor mobility.

A facile method was developed to synthesize pentacene derivative 6,13-dichloropentacene (DCP) in high yield. The absorption spectra and electrochemistry results showed that the introduction of chlorine substituents lowered the HOMO energy level and increased the environmental stability of the compound. Single crystal diffraction revealed that DCP adopted slipped face-to-face packing mode. π–π and C–H⋯Cl interactions were observed in the crystals. The thin film transistor characteristics showed that DCP exhibited high mobility (0.20 cm2 V−1 s−1), low threshold voltage (∼−2.0 V) and good stability.

A new method to prepare reduced graphene oxide (RGO) films was reported. In this method, RGO thin films can be prepared for large areas with controllable thickness and high temperature (>500 °C) is not required. The applications of RGO thin films as electrodes of organic field-effect transistors (OFETs) were investigated by bottom-contact p- and n-channel OFETs using copper phthalocyanine and copper hexadecafluorophthalocyanine as semiconductors. Transistor characterization showed the RGO electrode devices displayed higher mobilities than similar OFETs with Au electrodes, suggesting RGO is a good candidate for OFET electrodes.

The relationships between the molecular structure, self-assembly and charge transport properties of two fused-ring thienoacene isomers, a sickle-like syn isomer and a linear anti isomer, were studied from both an experimental and a theoretical perspective. Under the same self-assembly conditions, the syn isomer formed one-dimensional (1D) micro- and nanoribbons, while the anti isomer formed two-dimensional (2D) nanoplates (all were single crystals). The differences were assigned to the change in intermolecular interactions due to the tiny tuning of the molecular structures. The field-effect mobility in the single crystals of the syn isomer was about one-third as high as that of the anti isomer. The different transfer integrals of the isomers explained the observed different mobilities. This study opens a vivid window to examine the self-assembly and charge transport properties of organic semiconductors by using configurational isomers.

A new method to prepare reduced graphene oxide (RGO) films was reported. In this method, RGO thin films can be prepared for large areas with controllable thickness and high temperature (>500 °C) is not required. The applications of RGO thin films as electrodes of organic field-effect transistors (OFETs) were investigated by bottom-contact p- and n-channel OFETs using copper phthalocyanine and copper hexadecafluorophthalocyanine as semiconductors. Transistor characterization showed the RGO electrode devices displayed higher mobilities than similar OFETs with Au electrodes, suggesting RGO is a good candidate for OFET electrodes.

A facile method was developed to synthesize pentacene derivative 6,13-dichloropentacene (DCP) in high yield. The absorption spectra and electrochemistry results showed that the introduction of chlorine substituents lowered the HOMO energy level and increased the environmental stability of the compound. Single crystal diffraction revealed that DCP adopted slipped face-to-face packing mode. π–π and C–H⋯Cl interactions were observed in the crystals. The thin film transistor characteristics showed that DCP exhibited high mobility (0.20 cm2 V−1 s−1), low threshold voltage (∼−2.0 V) and good stability.

The relationships between the molecular structure, self-assembly and charge transport properties of two fused-ring thienoacene isomers, a sickle-like syn isomer and a linear anti isomer, were studied from both an experimental and a theoretical perspective. Under the same self-assembly conditions, the syn isomer formed one-dimensional (1D) micro- and nanoribbons, while the anti isomer formed two-dimensional (2D) nanoplates (all were single crystals). The differences were assigned to the change in intermolecular interactions due to the tiny tuning of the molecular structures. The field-effect mobility in the single crystals of the syn isomer was about one-third as high as that of the anti isomer. The different transfer integrals of the isomers explained the observed different mobilities. This study opens a vivid window to examine the self-assembly and charge transport properties of organic semiconductors by using configurational isomers.

A donor–acceptor–donor (D–A–D) type small molecule DHB-QDTB, with dicyano-substituted quinoidal benzo[1,2-b:4,5-b′]dithiophene as the acceptor, was designed and synthesized. A high electron mobility up to 0.88 cm2 V−1 s−1 was observed for DHB-QDTB based transistors under ambient conditions, suggesting quinoidal benzo[1,2-b:4,5-b′]dithiophene is an excellent acceptor unit in D–A type n-channel organic semiconductors.