Charge carrier dynamics in metalated polymers investigated by optical-pump terahertz-probe spectroscopy.

We report charge carrier dynamics in solid films of a series of metalated polymers based on Pt- and 4,7-di-2'-thienyl-2,1,3,-benzothiadiazole or 4,7-di-2'-thienothienyl-2,1,3,-benzothiadiazole upon photoexcitation of the pi-pi* transition using optical-pump terahertz-probe spectroscopy. Subpicosecond generated charge carriers recombine within 100 ps, but bound excitons persist. Application of the Drude-Smith model allows for estimation of the intrinsic mobility and internal quantum yield of charge carrier generation in these films. Thermal annealing is found to have no effect on nanometer scale charge transport.