Photosensitive junctions based on UV-modified graphene and inkjet-printed organic molecules

In this work, we report a novel method of mask-less doping of graphene channel in field-effect transistor configuration
by local inkjet printing of organic semiconducting molecules. Graphene-based transistor was fabricated via large-scale
technology, allowing for upscaling electronic device fabrication and lowering the device cost. The altering of
functionalization of graphene was performed through local inkjet printing of semiconducting molecules: N,N′-Dihexyl-
3,4,9,10-perylenedicarboximide (PDI-C6), 5,5′′′-Dihexyl-2,2′:5′,2′′:5′′,2′′′-quaterthiophene (HEX-4T-HEX) and
polyalanine (PANI). We found the effect of UV treatment on fabrication of graphene/organic junctions because of
change in graphene hydrophobic properties. We demonstrated the high resolution (about 50 μm) and accurate printing of
organic ink on UV treated chemical vapor deposited (CVD) graphene. The PANI/graphene junction demonstrate more
stable photoresponse characteristic for 470 nm diode illumination. The characteristics of PDI/graphene junction
demonstrate the saturation for high diode power because of organic crystals degradation. The photoresponse of 1 mA/W
was demonstrated for PANI/graphene junction at 0.3 V bias voltage. The developed method opens the way for local
functionalization of on-chip array of graphene by inkjet printing of different semiconducting organic molecules for
photonics and electronics application.