Polymer Electronics: To Be or Not to Be?

The realization that polymers can be used as active material in opto-electronic applications initiated substantial effort in the scientific community to explore new materials. Polymers can be made strong, flexible, lightweight, and can be mass produced. Furthermore, polymers can be processed at low temperatures, typically below 150 degrees C, creating the opportunity to use a range of plastic substrates instead of glass. Many polymers are soluble in organic solvents, making it possible to create electronically active "inks" that allow for solution-processed electronic components as light-emitting diodes and transistors. Examples of innovative new products based on semiconducting polymers are inkjet-printed displays, non-contact radio frequency identification tags, and sensors. However, the realization of polymeric displays is hindered by the relatively low efficiency of polymer-based light-emitting diodes. Major problems are the inability to realize multi-layers from solution, insufficient harvesting of triplet excitons and the presence of defects. Printed circuits of organic transistors are still hampered by stability issues and relatively low charge carrier mobility of the organic semiconductors. More recently, organic electrochemical transistors have been employed as biosensors. Herein, the fundamentals and recent progress of polymer-based light-emitting devices and transistors are being discussed.