Electrode Thickness Optimization in Color-Selective Inkjet-Printed Photosensitive Organic Field-Effect Transistors †

This work introduces a general solution for printing wavelength-selective bulk-heterojunction photosensitive organic field effect transistors (PS-OFETs) by addressing electrode thickness variation and the feasibility of color selectivity in detecting incident light. The inkjet-printed silver electrode thickness was varied from 125 to 950 nm by multilayer printing. PIF, IDFBR, and ITIC-4F were chosen as the active semiconductor materials with complementary optical absorption. Results indicate that PS-OFETs exhibit the best functionality at an electrode thickness of approximately 325 nm and an active material combination with PIF:IDFBR (1:1). For the 540 nm wavelength, a responsivity of 55 mAW$^{−1}$ was obtained. This is four-fold higher than the photoresponse obtained at 700 nm.