Measuring the bends

“Organic electronics offer a compelling opportunity to enable more demanding flexible electronic applications,” says polymer chemist Iain McCulloch of Saudi Arabia’s King Abdullah University of Science and Technology. But current measurements could be overstating their performance, he and his colleagues write in the journal Science¹.

Traditionally, electronics are made using inorganic conductive materials, such as silicon. The relatively new field of organic electronics involves the use of organic materials, such as synthetic polymers, in building electronic circuits. This could allow for less costly and more flexible devices, such as bendable and more rugged display screens or electronics that can be implanted in the human body.

Researchers have noticed, however, that the conventional method used to test how well devices conduct electrical charges, known as their “carrier mobility”, can in some cases overestimate the devices’ performance. “As the performance continually improves, we are now observing some unusual irregularities when trying to extract the carrier mobility from the electrical characteristics,” says McCulloch. 

This is because newer, high-performance organic electronics do not always have the same characteristics as their inorganic counterparts, based on which measurement models have been created. 

Inaccurate measurements can make it difficult for chemists to optimise the design of organic semiconductors, the researchers write. “Until better models and solutions to eliminate nonidealities are found, the best prescription is conservatism on absolute metrics and trends, particularly with small differences in electrical properties,” the researchers conclude.

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