Interface engineering in high-performance low-voltage organic thin-film transistors based on 2,7-dialkyl-[1]benzothieno[3,2-b][1]benzothiophenes

Atefeh Y Amin; Knud Reuter; Timo Meyer-Friedrichsen; Marcus Halik

doi:10.1021/la203041x

Interface engineering in high-performance low-voltage organic thin-film transistors based on 2,7-dialkyl-[1]benzothieno[3,2-b][1]benzothiophenes

Langmuir. 2011 Dec 20;27(24):15340-4. doi: 10.1021/la203041x. Epub 2011 Nov 18.

Authors

Atefeh Y Amin¹, Knud Reuter, Timo Meyer-Friedrichsen, Marcus Halik

Affiliation

¹ Organic Materials and Devices, Institute of Polymer Materials, Department of Materials Science, Friedrich-Alexander-University of Erlangen-Nürnberg, Martensstrasse 7, 91058 Erlangen, Germany.

PMID: 22044421
DOI: 10.1021/la203041x

Abstract

We investigated two different (2,7-dialkyl-[1]benzothieno[3,2-b][1]benzothiophenes; C(n)-BTBT-C(n), where n = 12 or 13) semiconductors in low-voltage operating thin-film transistors. By choosing functional molecules in nanoscaled hybrid dielectric layers, we were able to tune the surface energy and improve device characteristics, such as leakage current and hysteresis. The dipolar nature of the self-assembled molecules led to a shift in the threshold voltage. All devices exhibited high charge carrier mobilities of 0.6-7.0 cm(2) V(-1) s(-1). The thin-film morphology of BTBT was studied by means of atomic force microscopy (AFM), presented a dependency upon the surface energy of the self-assembled monolayer (SAM) hybrid dielectrics but not upon the device performance. The use of C(13)-BTBT-C(13) on hybrid dielectrics of AlO(x) and a F(15)C(18)-phosphonic acid monolayer led to devices with a hole mobility of 1.9 cm(2) V(-1) s(-1) at 3 V, on/off ratio of 10(5), small device-device variation of mobility, and a threshold voltage of only -0.9 V, thus providing excellent characteristics for further integration.