A chemical trick to make transistors smarter

An international research team shows in new research how adding molecular additives to polymer-based field-effect transistors can markedly improve their stability without leading to an undesirable increase in off current¹.

The molecular additives prevent water from interacting with the polymer and creating charge traps. The presence of water molecules in field-effect transistors usually traps electrons and shift turn-on voltage, affecting performance and operational stability.

But the new trick helps boost performance and reduce environmental degradation of transistors.  In fact, the scientists, including Jean-Luc Bredas from the King Abdullah University of Science and Technology, Saudi Arabia, found that adding the molecular additive tetracyanoquinodimethane to the polymer solution used in making transistors helped give them near-perfect environmental stability. 

This research could advance organic-semiconductor-based devices, in particular organic transistors, for a wide range of applications in displays and electronic circuits, according to lead investigator Henning Sirringhaus from the University of Cambridge, UK.

The additive-incorporated transistors are able to retain their properties even when exposed to a temperature of 70 degree Celsius for 12 hours in nitrogen-rich atmosphere.

This level of stability is very significant, explain the researchers, particularly in an organic light-emitting diode display where the transistors would need to operate reliably in a strictly inert, oxygen-free atmosphere.

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