Strain induced anisotropic effect on electron mobility in C60 based organic field effect transistors

Abstract

The electron mobility was found to increase (decrease) upon applied compressive (tensile) strain, respectively, when a high-performance flexible ${\mathrm{C}}_{60}$ -based organic field-effect transistor (OFET) was subjected to different bending radii. The observed almost twofold relative change in the electron mobility is considerably larger than that reported before for pentacene-based OFETs. Moreover, the strain dependency of electron mobility in ${\mathrm{C}}_{60}$ films is strongly anisotropic with respect to the strain direction measured relative to the current flow. Analysis within a hopping-transport model for OFET mobility suggests that the observed strain dependency on electron transport is dominated mostly by the change of inter-grain coupling in polycrystalline ${\mathrm{C}}_{60}$ films.