Time-of-flight measurements in thin films of regioregular poly(3-hexyl thiophene)

We have studied the transport of holes in thin films of regioregular poly(3 -hexyl thiophene) (RRPHT). In comparison to regiorandom poly(3-hexyl thioph ene) (PHT), RRPHT is a promising material for electronic devices, due to th e high field effect mobility observed. We have studied the photogenerated c harge carrier transport by using the integral time-of-flight (TOF) method. We have also studied the transport properties of the equilibrium charge car riers by a newly developed method of equilibrium charge carrier extraction in the case of a linearly increasing voltage. From TOF measurements in the subnanosecond time scale, it was experimentally obtained that the drift dis tance of holes is smaller than the inter-electrode distance in both PHT and RRPHT films and the mobility is higher than 10(-2) cm(2)/Vs. In the millis econd time scale we obtained additional low mobility of equilibrium holes i n RRPHT. (C) 2000 Elsevier Science S.A. All rights reserved.