Systematic reliability study of top-gate p- and n-channel organic field-effect transistors.

We report on a systematic investigation on the performance and stability of p-channel and n-channel top-gate OFETs, with a CYTOP/Al2O3 bilayer gate dielectric, exposed to controlled dry oxygen and humid atmospheres. Despite the severe conditions of environmental exposure, p-channel and n-channel top-gate OFETs show only minor changes of their performance parameters without undergoing irreversible damage. When correlated with the conditions of environmental exposure, these changes provide new insight into the possible physical mechanisms in the presence of oxygen and water. Photoexcited charge collection spectroscopy experiments provided further evidence of oxygen and water effects on OFETs. Top-gate OFETs also display outstanding durability, even when exposed to oxygen plasma and subsequent immersion in water or operated under aqueous media. These remarkable properties arise as a consequence of the use of relatively air stable organic semiconductors and proper engineering of the OFET structure.

Stable solution-processed molecular n-channel organic field-effect transistors.

A new solution-processable small-molecule containing electron-poor naphthalene diimide and tetrazine moieties has been synthesized. The optimized spin-coated n-channel OFETs on glass substrate shows electron mobility value up to 0.15 cm(2) V(-1) s(-1) . Inkjet-printed OFETs are fabricated in ambient atmosphere on flexible plastic substrates, which exhibits an electron mobility value up to 0.17 cm(2) V(-1) s(-1) and also shows excellent environmental and operational stability.

A universal method to produce low-work function electrodes for organic electronics.

Organic and printed electronics technologies require conductors with a work function that is sufficiently low to facilitate the transport of electrons in and out of various optoelectronic devices. We show that surface modifiers based on polymers containing simple aliphatic amine groups substantially reduce the work function of conductors including metals, transparent conductive metal oxides, conducting polymers, and graphene. The reduction arises from physisorption of the neutral polymer, which turns the modified conductors into efficient electron-selective electrodes in organic optoelectronic devices. These polymer surface modifiers are processed in air from solution, providing an appealing alternative to chemically reactive low-work function metals. Their use can pave the way to simplified manufacturing of low-cost and large-area organic electronic technologies.