Interfacial and Nanostructural Enhancements in Organic Semiconductor Sensors and Diodes

Interfaces often control the performance and activity of organic devices and can be harnessed for new and enhanced functions. Interface engineering has enabled us to modulate the threshold (turn-on) voltage of a field effect transistor made from a solution-deposited semiconductor, and to increase the switching speed of an organic semiconductor diode by three orders of magnitude. Interfacial chemistry provides capabilities for using organic transistors as sensors for vapors of military and security interest, especially nerve gas simulants. As the devices become thinner and thinner, to the point where they are almost entirely interfacial, sensitivity enters the parts-per-billion regime and response speeds decrease from minutes to seconds. Selectivity and sensitivity are enhanced through the use of receptor functionality on surfaces. Receptor chemistry and electrostatics both contribute to the sensing mechanism.