Effect of solution aging on morphology and electrical characteristics of regioregular P3HT FETs fabricated by spin coating and spray coating

The paper reports on a comparative study of poly(3-hexylthiophene) (P3HT) films as well as P3HT organic field effect transistors (OFETs) fabricated by the spin coating and spray coating techniques, using fresh and aged (for 2 months) chloroform solutions. The films obtained from aged solutions contain nanostructured fibers of the polymer. The presence of nanofibers in P3HT thin films affects the performance of the OFETs: charge carrier mobilities in the samples deposited from the aged solutions appeared over one order of magnitude higher than those fabricated using fresh solutions. Particularly high mobilities, exceeding 10−2 cm2 V−1 s−1, were found in spin coated samples deposited from aged solutions. Additionally, the latter samples exhibit a certain degree of anisotropy, associated with the action of centrifugal force during the deposition.

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► Study of P3HT-based transistors relating performance to way of their fabrication.
► Comparison of OFETs deposited from fresh and aged solutions by spray and spin coating.
► Presence of nanofibers promotes higher carrier mobilities.
► Ordering effect of centrifugal force in spin coated samples deposited from aged solutions.