Mobility versus Alignment of a Semiconducting pi-Extended Discotic Liquid-Crystalline Triindole

Ruiz, Constanza and Pandey, Upendra K and Termine, Roberto and Garcia-Frutos, Eva M and Lopez-Espejo, Guzman and Ponce Ortiz, Rocio and Huang, Wei and Marks, Tobin J and Facchetti, Antonio and Ruiz Delgado, Carmen M and Golemme, Attilio and Gomez-Lor, Berta (2016) Mobility versus Alignment of a Semiconducting pi-Extended Discotic Liquid-Crystalline Triindole. In: ACS APPLIED MATERIALS & INTERFACES, 8 (40). pp. 26964-26971.

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Abstract

The p-type semiconducting properties of a triphenylene-fused triindole mesogen, have been studied by applying two complementary methods which have different alignment requirements. The attachment of only three flexible alkyl chains to the nitrogen atoms of this pi-extended core is sufficient to induce columnar mesomorphism. High hole mobility values (0.65 cm(2) V-1 s(-1)) have been estimated by space-charge limited current (SCLC) measurements in a diode-like structure which are easily prepared from the melt, rendering this material a good candidate for OPVs and OLEDs devices. The mobility predicted theoretically via a hole-hopping mechanism is in very good agreement with the experimental values determined at the SCLC regime. On the other hand the hole mobility determined on solution processed thin transistors (OFETs) is significantly lower, which can be rationalized by the high tendency of these large molecules to align on surfaces with their extended pi-conjugated core parallel to the substrate as demonstrated by SERS. Despite the differences obtained with the two methods, the acceptable performance found on OFETs fabricated by simple drop-casting processing of such an enlarged aromatic core is remarkable and suggests facile hopping between neighboring molecular columns owing to the large conducting/isolating ratio found in this discotic compound.

Item Type:	Journal Article
Publication:	ACS APPLIED MATERIALS & INTERFACES
Additional Information:	Copy right for this article belongs to the AMER CHEMICAL SOC, 1155 16TH ST, NW, WASHINGTON, DC 20036 USA
Department/Centre:	Division of Interdisciplinary Sciences > Interdisciplinary Centre for Energy Research
Date Deposited:	03 Dec 2016 06:48
Last Modified:	03 Nov 2018 12:26
URI:	http://eprints.iisc.ac.in/id/eprint/55329

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