Organic electronics has recently gained attention as a new field promising cheaper, flexible, and large-scale
devices. Although photolithography has proven to be a high-resolution and high-throughput patterning method with
excellent registration capabilities, the emerging field of organic electronics has been largely unsuccessful in adapting this
well-established method as a viable approach to patterning. Chemical compatibility issues between organic materials and
the processing solvents and chemicals required by photolithography have been the main problem. This challenge has led
us to identify a set of non-damaging processing solvents and to develop alternative imaging materials in order to extend
photolithographic patterning methods to organic electronics.
We have identified supercritical carbon dioxide and hydrofluoroether (HFE) solvents as chemically benign to
organic electronic materials and which are also suitable as processing solvents. We refer to these solvents as orthogonal
in that they do not substantially interact with traditional aqueous and organic solvents. Multi-layered devices are easily
realized by exploiting this orthogonality property; subsequent layers are deposited and patterned without damaging or
otherwise adversely affecting previously deposited underlying layers. We have designed and synthesized novel
photoresists, which are processible in these benign solvents.