Nondispersive hole transport in a polyfluorene copolymer with a mobility of 0.01cm2V−1s−1

Abstract
The hole mobility in the fluorene copolymer poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-( 4 , 4 ′ -( N -(4-sec-butylphenyl)) diphenylamine)] (TFB) was measured using the time-of-flight technique. Transport was found to be nondispersive throughout the temperature range between 220 and 350 K , indicating the absence of intrinsic traps in this material. At room temperature, TFB shows a hole mobility of 0.01 cm 2 V − 1 s − 1 , with a weak field dependence. The hole mobility is independent of sample thickness in the range between 0.9 and 6.4 μ m . These results are in agreement with a narrow transportmanifold, with a width of 65.9 ± 0.5 meV .