INVITED: Roll-to-roll processing of flexible electronics: transistors, circuits and devices

The breakthrough of flexible electronics depends upon suitable large-scale manufacturing routes, likely requiring very low cost, high-throughput processing techniques.  Our approach to development of organic electronics considered high-speed roll-to-roll processing routes already employed industrially to consider their applicability in creating transistors and circuits.  This paper will consider the advantages and challenges of a vacuum-deposition approach, and then discuss the development of organic field effect transistors that use evaporation for all required layers.  These transistors have been employed in simple circuit elements and these circuits and transistor arrays have shown yields of close to 100%.  For circuit development, in-line in-vacuum high throughput patterning techniques require further exploration, and first steps considered in Oxford will be described.  The development of such circuit elements along with our ongoing research in sensors, photovoltaics and display technologies, such as phase change materials, will be discussed as part of our research program on wearable and flexible technologies.