(Invited) Achieving Stable Organic Transistors By Eliminating the Major Degradation Pathways

Abstract

Organic semiconductors (OSCs) have attracted a great deal of attention over the past decades given their unique properties, which provide an opportunity to incorporate electronics in non-traditional areas such as bio-integrated devices, flexible and rollable displays or clothing. Coupled with low-cost processing and chemical versatility, these materials are gradually becoming an integral part of various components in contemporary optoelectronic applications. For example, the organic field-effect transistors (OFETs) represent the basic building blocks of displays, radio frequency identification tags and conformable sensors. Along with a performance that should match the application specific requirements, maintaining this performance during operation is a prerequisite for any technology. Therefore, identifying the sources and mechanisms leading to operational instabilities are crucial in eliminating their impact, to ultimately achieve the much-needed stability to make these devices components in real-life applications. In this presentation, I will discuss the sources of instabilities in organic transistors and how they manifest in device operation. I will then describe a technique which provides a reliable diagnostic tool to identify with high accuracy the environmental and operational degradation pathways occurring in OFETs during operation. By identifying the most probable degradation pathways, we developed new device design rules which resulted in OFETs with unparalleled operational stability in both staggered and coplanar configurations regardless of the active material (small molecule and polymeric OSCs), as confirmed by the constant mobility and exceptionally low threshold voltage shift of ΔVth = 0.1 eV achieved under aggressive bias stress conditions for 500 min in ambient air.The work was done in collaboration with Hamna F. Iqbal, Qianxiang Ai, Karl J. Thorley, Hu Chen, Iain McCulloch, Chad Risko, and John E. Anthony