Optimizing functionalization schemes for small-molecule organic transistor materials

Enabling efficient charge transport in organic thin-film transistors requires precise control over the interactions between the organic molecules that fill the active channel area. We long ago developed a simple functionalization approach for acenes and heteroacenes that simplified the crystal engineering of organic semiconductors, while simultaneously enhancing their solubility and stability. This approach generally covers control of the bulk arrangement of the molecules, but generally does not impact potential dynamic disorder - thermal vibrations in the crystalline film that can disrupt intermolecular electronic coupling. We are currently exploring several approaches to mitigate this type of disorder, ranging from decoupling portions of the core chromophore, rigidifying the linker between the solubilizing group and the core, and installing 'buffer' functional groups to inhibit long-axis vibrations. The results from these studies will be presented, along with approaches to control the crystal packing of non-linear aromatic cores.