Accelerated photopolymerization and increased mobility in C_(60) field-effect transistors studied by ultraviolet photoelectron spectroscopy

摘要

Ultraviolet photoelectron spectroscopy (UPS) of C_(60) thin-film field-effect transistors was measured with biasing gate voltages. A time-dependent change in the electronic structure of the C_(60) film was observed during the UPS measurement, which has never been observed in a C_(60) film grown on a conductive substrate. The change was attributed to the accelerated polymerization of C_(60) by comparing the UPS with that of the photopolymerized C_(60). The polymerization was associated with the increase in the field-effect electron mobility. This result indicates that mobile carriers produce reactive radicals in organic semiconductors.