ANISOTROPY OF THE CHARGE-CARRIER MOBILITY IN POLYDIACETYLENE CRYSTALS

The anisotropic mobility of excess charge carriers in pure and mixed c rystals of two polydiacetylene derivatives was determined;The charge c arriers were produced by pulsed irradiation and.detected by time-resol ved measurement of the microwave conductivity. The charge-carrier mobi lity was measured as a function of the orientation of the polymer back bone in the crystal with respect to the probing electric microwave fie ld. A lower limit:in the intrinsic anisotropy;in the charge-carrier mo bility was found to be 15 in favor of charge transport in the directio n of the polymer backbone as compared to the transverse direction for polydiacetylene-(bis p-fluorobenzene Sulfonate) (pFBS), while value of 90 was found for polydiacetylene-(bis p-toluene sulfonate) (pTS) and the 50:50 pTS/FBS copolymer, A lower limit of the change-carrier mobil ity along the backbone of 3 cm(2)/V s was found for both pTS and pFBS. The charge-carrier mobility in the copolymer; was found;to be one old er of magnitude lower than in the pure polymers. (C) 1998 American Ins titute of Physics.