Band Transport and Trapping in Didodecyl[1]benzothieno[3,2‑b][1]benzothiophene Probed by Terahertz Spectroscopy

• Published in: The journal of physical chemistry letters Vol. 8; no. 21; pp. 5444 - 5449
• Main Authors: Arend, Thomas R., Wimmer, Andreas, Schweicher, Guillaume, Chattopadhyay, Basab, Geerts, Yves H., Kersting, Roland
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 02-11-2017
• ISSN: 1948-7185; 1948-7185
• DOI: 10.1021/acs.jpclett.7b02304

Terahertz electromodulation spectroscopy provides insight into the material-inherent transport properties of charge carriers in organic semiconductors. Experiments on didodecyl[1]­benzothieno­[3,2-b]­[1]­benzothiophene (C12-BTBT-C12) devices yield for holes an intraband mobility of 9 cm2 V–1 s–1. The short duration of the THz pulses advances the understanding of the hole transport on the molecular scale. The efficient screening of Coulomb potentials leads to a collective response of the hole gas to external fields, which can be well described by the Drude model. Bias stress of the devices generates deep traps that capture mobile holes. Although the resulting polarization across the device hinders the injection of mobile holes, the hole mobilities are not affected.