Two-dimensional charge carrier mobility studies of regioregular P3HT

摘要

Charge carrier mobility of regioregular poly(3-hexylthiophene) (RR-P3HT) is studied within the temperature range 77 - 370 K using thin film field-effect transistors (FETs). The non-monotonic thickness dependence of the room temperature field-effect mobility (#mu#) has a maximum at approx 10 nm. The film thickness was varied both by changing the concentration of the solution of RR-P3HT in chloroform and by varying the spin coating speed. For films about 5-10 nm thick the maximum mobility is #mu# approx 10~(-3) cm~2V~(-1)s~(-1) and the maximum on-off ratio is > 10~5. At low T, #mu#(T) = #mu#_0 exp(-(T_0/T)~(0.33)). The results support Mott's variable-range hopping model for two-dimensional systems.