Charge injection barrier at the pentacene thin film and electrode interface characterized by time-resolved electrostatic force microscopy.

This article focuses on investigating the electrical properties of the metal–organic interface in organic thin-film transistors (OTFTs) by using time-resolved electrostatic force microscopy (tr-EFM) to study a single pentacene grain connected to a gold (Au) electrode. The study reveals that the grain–electrode interfacial resistance dominates the electrical behavior, exhibiting nonlinear and asymmetric current–voltage characteristics consistent with a Schottky junction at the interface. By modeling the interface with an equivalent circuit of resistance and capacitance, the researchers extracted femto-ampere-order current-to-voltage characteristics, demonstrating tr-EFM’s capability to measure extremely small hole injection currents at the nanoscale. These findings provide insight into the intrinsic carrier injection and removal processes at the metal–organic interface, which are typically obscured in conventional measurements involving multiple grain boundaries.