High-Mobility, Ultrathin Organic Semiconducting Films Realized by Surface-Mediated Crystallization

Abstract

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 mm-sized semiconductor platelets that are only few nm thick and thus highly attractive for application in transistors. Based on the novel high-performance perylene-diimide, we show in as-grown, only 3 nm thin crystals electron mobilities of above 4 cm²/Vs and excellent bias stress stability. We suggest that the established systematics on solvent parameters can provide the basis of a general framework for more deterministic crystallization of other small molecules.