Crystal engineering of alkylethynyl fluoroanthradithiophenes

Fluoroanthradithiophenes are well known organic semiconductors, where alkynyl substituents featuring silicon and germanium exhibit hole mobilities in excess of 5 cm² V⁻¹ s⁻¹. A key feature to achieve these performance levels is the 2-dimensional brickwork packing of triethylsilyl and triethylgermyl side chains, which direct solid-state packing, increase molecular stability, and increase solution processability for cheap and large scale fabrication. We have recently reported side chains utilising carbon in place of the other group 14 atoms, resulting in less favourable 1-dimensional molecular packing. Here we present the synthesis of new derivatives which adopt 2-D brickwork packing without the use of silicon or germanium to determine substituent effects on charge carrier mobility.