Monday, 01 January, 2018
High-Mobility, Ultrathin Organic Semiconducting Films Realized by Surface-Mediated Crystallization
I. Vladimirov, M. Kellermeier, T. Gessner, Z. Molla, S. Grigorian, U. Pietsch, L. S. Schaffroth, M. Kuhn, F. May and R. T. Weitz -
Nano Letters, 10.1021/acs.nanolett.7b03789 (2018)
The functionality of common organic semiconductor materials is determined by their chemical structure and crystal modification. While the former can be fine-tuned via synthesis, a priori control over the crystal structure has remained elusive. We show that the surface tension is the main driver for the plate-like crystallization of a novel small organic molecule n-type semiconductor at the liquid–air interface. This interface provides an ideal environment for the growth of millimeter-sized semiconductor platelets that are only few nanometers thick and thus highly attractive for application in transistors. On the basis of the novel high-performance perylene diimide, we show in as-grown, only 3 nm thin crystals electron mobilities of above 4 cm2/(V s) and excellent bias stress stability. We suggest that the established systematics on solvent parameters can provide the basis of a general framework for a more deterministic crystallization of other small molecules.