Rapid Diffraction Limited Photo-Lithography of Organic Semiconductors

For any inorganic semiconductor device, photolithography is used to micro/nano pattern the areas over which metal electrodes are deposited, semiconductor is etched, ions are implanted, or oxide is grown. For organic semiconductors, academic articles only focus on materials property measurements because there is no easy and universal method to pattern the organic semiconductor or the doping density. Here we correct this gap in processing capabilities. We present a method to rapidly pattern any semiconducting polymer with diffraction limited resolution using a conventional maskless photolithography instrument. We demonstrate maximum write-speeds of several cm/min for patterning with <1µm features. We demonstrate the writing and doping of semiconducting nanowires made from poly-3-hexylthiophene (P3HT) and Poly[2,5-bis(2-octyldodecyl)pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione -3,6-diyl)-alt-(2,2’;5’,2’’;5’’,2’’’-quaterthiophen-5,5’’’-diyl)] (DPP-4T). These nanowires can be written at any location on the substrate and can include bends or T’s. Typical wire width of 400 nm and length of >100 µm demonstrate the ability to pattern conjucated polymers with unprecedented resolution and speed. All equipment and processes are consistent with modern photo-lithography instruments in facilities and can be directly adopted.