(Poly(3,4-ethylenedioxythiophene):Polystyrene Sulfonate):Polytetrafluoroethylene for Use in High-Performance and Stable Bottom-Contact Organic Field-Effect Transistors

Abstract

We successfully fabricated highly stable pentacene-based bottom-contact organic field-effect transistors (OFETs) with good charge injection properties at the electrode/organic semiconductor interface, obtained by optimizing the composition of solution-processed (poly(3,4-ethylenedioxythiophene):polystyrene sulfonate):polytetrafluoroethylene ((PEDOT:PSS):PTFE)-treated Au source/drain (S/D) electrodes. The (PEDOT:PSS):PTFE layer was deposited on the Au layer by spin-coating a mixture solution. The work function of the electrode increased from 4.84 to 5.21 eV as the PTFE concentration increased, accompanied by an interface dipole at the electrode surface. The optimized (PEDOT:PSS):PTFE (0.95:0.05)-treated electrodes significantly reduced the charge injection barrier at the electrode/semiconductor interface to achieve efficient charge transfer in the OFETs. Bottom-contact OFETs prepared with the optimized (PEDOT:PSS):PTFE-treated S/D electrodes had a field-effect mobility of 0.16 cm(2)/(V.s), which exceeded that of PEDOT:PSS-treated S/D electrodes (0.073 cm(2)/(V.s)). The operational stability of the optimized device was remarkable under gate-bias stress (V-G = -40 V over 3 h).