Highly stable organic polymer field-effect transistor sensor for selective detection in the marine environment.

In recent decades, the susceptibility to degradation in both ambient and aqueous environments has prevented organic electronics from gaining rapid traction for sensing applications. Here we report an organic field-effect transistor sensor that overcomes this barrier using a solution-processable isoindigo-based polymer semiconductor. More importantly, these organic field-effect transistor sensors are stable in both freshwater and seawater environments over extended periods of time.

Flexible polymer transistors with high pressure sensitivity for application in electronic skin and health monitoring.

Flexible pressure sensors are essential parts of an electronic skin to allow future biomedical prostheses and robots to naturally interact with humans and the environment. Mobile biomonitoring in long-term medical diagnostics is another attractive application for these sensors. Here we report the fabrication of flexible pressure-sensitive organic thin film transistors with a maximum sensitivity of 8.

Integrated materials design of organic semiconductors for field-effect transistors.

The past couple of years have witnessed a remarkable burst in the development of organic field-effect transistors (OFETs), with a number of organic semiconductors surpassing the benchmark mobility of 10 cm(2)/(V s). In this perspective, we highlight some of the major milestones along the way to provide a historical view of OFET development, introduce the integrated molecular design concepts and process engineering approaches that lead to the current success, and identify the challenges ahead to make OFETs applicable in real applications.

Alkynylated phenazines: synthesis, characterization, and metal-binding properties of their bis-triazolyl cycloadducts.

We have synthesized a series of ethynylated phenazines and their bis-triazolyl cycloadducts to serve as metal ion sensors. Binding of metal ions is achieved through coordination to the phenazine nitrogen atom and the triazole ring. To allow metal sensing in aqueous solution, the triazole units are substituted with water-soluble ethylene glycol chains.

Synthesis and optical properties of diaza- and tetraazatetracenes.

A series of functionalized diaza- and tetraazatetracenes was synthesized, either by condensation of an aromatic diamine with an ortho-quinone/diethyloxalate followed by chlorination with POCl(3) to give diazatetracenes or by palladium-catalyzed coupling of a phenylenediamine with various 2,3-dichloroquinoxalines to give tetraazatetracenes (after oxidation with MnO(2)). Representative examples included halogenated and nitrated derivatives. The optical properties of these azatetracenes were discussed with respect to their molecular structures and substitution patterns.

Effects of electronegative substitution on the optical and electronic properties of acenes and diazaacenes.

Large acenes, particularly pentacenes, are important in organic electronics applications such as thin-film transistors. Derivatives where CH units are substituted by sp(2) nitrogen atoms are rare but of potential interest as charge-transport materials. In this article, we show that pyrazine units embedded in tetracenes and pentacenes allow for additional electronegative substituents to induce unexpected redshifts in the optical transitions of diazaacenes.

Water-soluble benzo- and naphtho-thiadiazole-based bistriazoles and their metal-binding properties.

A click reaction furnishes water-soluble acenothiadiazole-based bistriazoles with red-shifted absorption and emission characteristics.

Alkynylated aceno[2,1,3]thiadiazoles.

Enlarged acenothiadiazoles, which are easily prepared, display attractive optical and electrochemical properties. The annulation of thiadiazole to anthracene gives a stable material with optical properties similar to those of substituted pentacenes.

6,13-Diethynyl-5,7,12,14-tetraazapentacene.

A new relative of pentacene: The dialkynylated tetraazapentacene (see figure) was prepared by a two-step synthesis from the corresponding quinone derivative. The heteroacene is an air-stable, dark-blue, crystalline material and is of great interest as a potential organic n-electron-transport material.