Ambipolar Charge Transport in Organic Field-Effect Transistors Based on Lead Phthalocyanine with Low Band Gap Energy

The organic semiconductor, lead phthalocyanine (PbPc) with a low band gap energy of 1.2 eV is demonstrated as an active material for high-performance ambipolar organic field-effect transistors (OFETs). For the ambipolar OFETs with Au source–drain electrodes, the field-effect electron mobility was calculated to be 8.3 × 10 -4 cm 2 V -1 s -1 , when the threshold voltage was 31 V. On the other hand, the field-effect hole mobility was calculated to be 7.1 × 10 -4 cm 2 V -1 s -1 , when the threshold voltage was -58 V. After annealing the device for 12 h at 100 °C, the performance was improved and exhibited field-effect mobilities of the order of 10 -3 cm 2 V -1 s -1 for both carriers.