| Abstract | The effects of exposure of polymeric thin-film transistors (TFTs) to the ambient atmosphere, oxygen, and ozone were investigated. The off-state current increased and the threshold voltage became more positive for TFTs made with several thiophene-based polymers when exposed to the ambient. Exposure to purified air did not change the characteristics of TFTs. Exposure to ozone caused similar changes as exposure to the ambient. Density functional calculations showed that ozone forms a complex with polythiophene, that is, a shallow acceptor. These results suggest that ozone in the ambient can cause changes in electrical characteristics of polythiophene-based TFTs rather than oxygen. (c) 2007 American Institute of Physics. |
