N-type doping of poly(p-phenylene vinylene) with air-stable dopants

The electron transport in poly(p-phenylene vinylene) (PPV) derivatives blended with the air-stable n-type dopant (4-(1,3-dimethyl-2,3-dihydro-1H-benzoimidazol-2-yl)phenyl)dimethylamine (N-DMBI) is investigated. This dopant is activated after thin film deposition by annealing and strongly enhances the electron transport due to filling of electron traps as well as donation of free electrons to the lowest unoccupied molecular orbital (LUMO) of PPV. As a result, the electron current in a doped device exceeds the trap-free hole current. The total generated free electron density in the LUMO by the dopant typically amounts to 10(23) m(-3). (C) 2011 American Institute of Physics