Room-temperature and solution-processed vanadium oxide buffer layer for efficient charge injection in bottom-contact organic field-effect transistors

Abstract We introduce a room temperature and solution-processible vanadium oxide (VO x ) buffer layer beneath Au source/drain electrodes for bottom-contact (BC) organic field-effect transistors (OFETs). The OFETs with the VO x buffer layer exhibited higher mobility and lower threshold voltages than the devices without a buffer layer. The hole mobility with VO x was over 0.11 cm 2 /V with the BC geometry with a short channel length (10 μm), even without a surface treatment on SiO 2 . The channel width normalized contact resistance was decreased from 98 kΩ cm to 23 kΩ cm with VO x . The improved mobility and the reduced contact resistance were attributed to the enhanced continuity of pentacene grains, and the increased work function and adhesion of the Au electrodes using the VO x buffer layer.