Dopant Induced Solubility Control Patterning of Conjugated Polymers

The solubility of semiconducting polymers can be “switched off” using addition of a high electron affinity molecular dopant. Spontaneous charge transfer with the dopant generates an organic salt that is completely insoluble in non-polar solutions. Here we demonstrate both chemical and optical mechanisms by which the doping can be reversed and the solubility of the polymer is “switched back on.” Using these techniques, we are able to vertically stack and laterally pattern mutually soluble polymer layers, which are vital processing steps needed to expand the use of organic semiconductors in device applications. Optimization of these techniques has yielded diffraction limited film patterning with regular features of 200-300 nm with only solution processing steps and direct write laser patterning. Comparison of patterned and initial samples shows no change in the optical, electrical or chemical properties of the polymer. This means that the film is quantitatively dedoped after the patterning process is complete yielding intrinsic semiconducting polymer that is nano-patterned. Dopant induced solubility control (DISC) patterning offers a new avenue to process semiconducting polymers with applications in all areas of organic electronics.