Air-stable n-channel organic semiconductors based on perylene diimide derivatives without strong electron withdrawing groups

Two n-channel organic semiconductors based on perylene diimide derivatives without strong electron-withdrawing groups were presented that showed high mobilities and were air-stable. Both compounds, tetrachloroperylene tetracarboxyldiimide (TC-PTCDI) and N,N'-bis(2-phenylethyl)perylene-3,4:9:10- bis-(dicarboximide) (BPE-PTCDI), were used as pigments in paints and as photoconductors. A highly doped n-type Si wafer, with a thermally grown dry oxide layer as the gate dielectric, was used as the substrate. The electrical characteristics of top-contact organic thin-film transistor (OTFT) devices were measured in ambient laboratory conditions by using a Keithley 4200-SCS semiconductor parameter analyzer. Air-stability measurements of TC-PTCDI and BPE-PTCDI TFTs were carried out by monitoring the charge-carrier mobilities and on/off ratios as a function of time. These TFTs were potentially useful air-stable n-type semiconductors for thin-film transistors in CMOS circuits and photovoltaic devices.