Probing the electronic properties of self-organized poly(3-dodecylthiophene) monolayers by 2D STS imaging at the single chain scale

Nano Letters 6, 1711 - 1718 (2006)

Probing the electronic properties of self-organized poly(3-dodecylthiophene) monolayers by 2D STS imaging at the single chain scale

L. Scifo, M. Dubois, M. Brun, P. Rannou, S. Latil, A. Rubio, B. Grevin

We report on two-dimensional (2D) scanning tunneling spectroscopy (STS) of regioregular poly(3-dodecylthiophene) (P3DDT) films self-organized on highly oriented pyrolytic graphite (HOPG), with the support of simulations combining ab initio and semi-empirical approaches. Spectroscopic images are achieved at the single chain scale, which allows scrutinizing the electronic consequences of chain folds and π-stacking effects through spectroscopic contrasts. While chain folds do not locally increase the polymer bandgap more than a few tens of meV, a striking widening of the STS conductance gap is observed in case of electronic tunneling through two interacting polymer layers. Scenarios based on non planar configuration of thiophene cycles within the second layer or variations of the charge screening effects are proposed to explain this phenomenon.

Additional Information

Download
Preprint - 419.96 KB
Doi
http://dx.doi.org/10.1021/nl061018w

Related Research Areas