Christopher John Drury

Organic field-effect transistors and all-polymer integrated circuits

Electrical properties of field-effect transistors made of different solution processable organic semiconductors are described. The temperature and gate-voltage dependence of the mobility is shown and theoretically described using a model based on the variable-range hopping of charge carriers in an exponential density of states. Furthermore, a technology has been developed to make all-polymer integrated circuits. It involves reproducible fabrication of field-effect transistors on flexible substrates, where the semiconducting, conducting and insulating parts are all made of polymers. Integrated circuits consisting of more than 300 field-effect transistors are demonstrated.

Polymeric integrated circuits and light-emitting diodes

All-polymer flexible integrated circuits have been fabricated using a potentially low-cost technology. Combination with commodity anti-theft stickers has led to functional radio frequent identification transponders. Polymeric light-emitting diodes (PLEDs) opened the way to cost efficient, large area display-applications. Directions for further enhancement of their performance are presented.

Low-cost all-polymer integrated circuits

A technology has been developed to make all-polymer integrated circuits. It involves reproducible fabrication of field-effect transistors in which the semiconducting, conducting and insulating parts are all made of polymers. The fabrication on flexible substrates uses spin-coating of electrically active precursors and patternwise exposure of the deposited films. In the whole process stack-integrity is maintained. Vertical interconnects are made mechanically. As a demonstrator for the technology functional 15-bit programmable code generators are fabricated. These circuits still operate when the foils are sharply bent. Due to the limited number of process steps the technology is potentially inexpensive.