Abstract
Results from studies of spin dependent transport in the hole transporting organic semiconductor regioregular poly 3-hexylthiophene (RR-P3HT) are reported. The organic spin valves were grown on glass, with the structure Fe50Co50/RR-P3HT/Ni81Fe19. RR-P3HT was cast from five different solvents with different boiling points; 1,2,4 trichlorobenzene, toluene, xylene, chloroform, and chlorobenzene. Magnetoresistance measurements were carried out at room temperature. Spin dependent transport was only observed when toluene, xylene, and annealed 1,2,4 trichlorobenzene were used as solvents. Results are interpreted on the basis of differences in the RR-P3HT morphology induced by different solvents under fixed processing conditions. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3056409]