Contact and Interconnect Considerations for Organic and Flexible Electronics

Flexible electronics has emerged as a promising technology for demonstration of smart and wearable products due to inherent capabilities for low temperature, low cost, and large-area processing along with multi-functional capabilities in devices. Moreover, this technology has shown other important advantages over conventional electronics such as possibility of fabrication with natural materials and biodegradable substrates leading a path toward eco-sustainable, edible, and green electronics. Organic field-effect/thin-film transistors (FETs/TFTs) are widely explored active devices for flexible electronics due to their suitability for flexible circuits and sensing applications. These devices can act as a crucial block for smart wearable applications such as real-time health monitoring, electronic textiles, and electronic skin due to flexibility and conformability. However, in real systems, these devices face various mechanical, thermal, electrical, and other environmental stimulations during operation. Hence, these devices should be highly stable and reliable under internal or external influences. For integration of the flexible devices in real systems, various contact resistances have to be minimized. Moreover, parasitic effects arising from overlaps and interconnects have to be carefully looked into. In this chapter, firstly, a historical perspective along with potential application areas of flexible electronics are summarized. Further, crucial aspects for designing high-performance organic TFTs with low contact resistance are discussed. New ways adapted by researchers for designing interconnects for flexible and skin-like systems are discussed. Finally, options for alternative natural and biodegradable materials and processes are discussed aiming for eco-sustainable, ingestible, and green electronics.