High mobility n-type thin-film transistors based on N,N′-ditridecyl perylene diimide with thermal treatments

The authors demonstrated that $N,N^{\prime }$ -ditridecyl-3,4,9,10-perylenetetracarboxylic diimide (PTCDI-C13) thin-film transistors (TFTs) exhibited high field-effect electron mobility of $2.1{\mathrm{cm}}^2∕\mathrm{V}\mathrm{s}$ by just annealing at an adequate temperature $(140°\mathrm{C})$ after the TFT fabrications. While PTCDI-C13 formed $c$ -axis oriented thin films, the thermal treatments improved crystallinity of the thin films as revealed by x-ray diffraction. The thermal treatment also affected thin-film morphologies; the morphologies changed from oval ball-like grains to flat and large tilelike grains, which had molecular height steps and whose size reached several micrometers.