Intrachain versus interchain electron transport in poly(fluorene-alt-benzothiadiazole):: A quantum-chemical insight

Poly(9,9-di-n-octylfluorene-alt-benzothiodiazole) [F8BT], displays very different charge-transport properties for holes versus electrons when comparing annealed and pristine thin films and transport parallel (intrachain) and perpendicular (interchain) to the polymer axes. The present theoretical contribution focuses on the electron-transport properties of F8BT chains and compares the efficiency of intrachain versus interchain transport in the hopping regime. The theoretical results rationalize significantly lowered electron mobility in annealed F8BT thin films and the smaller mobility anisotropy (mu(vertical bar vertical bar)/mu(perpendicular to) measured for electrons in aligned films (i.e. 5-7 compared to 10-15 for holes).