High mobility organic single crystal transistors based on soluble triisopropylsilylethynyl anthracene derivatives

A series of new anthracene based semiconductors are designed and synthesized. By substituting appropriate acenes at the 2,6-positions of triisopropylsilylethynyl anthracene (NMR, IR, DSC and TGA spectra and crystallographic information of TIPSAntBT and TIPSAntNa), two different derivatives were prepared. Especially, TIPSAntNa (naphthalene as a side group) showed superior performance when it was used as channel material. A hole mobility as high as 3.7 cm² V⁻¹ s⁻¹ was obtained from single crystal OFETs. To elucidate the origin of this high performance, we carried out comparative studies to investigate the direct relationship between the molecular-packing parameters and the field-effect mobility in single-crystal OFETs because the performance of such single-crystal OFETs is not affected by defects and grain boundaries. Comparing TIPSAN single crystal OFETs having four different acene derivatives, and applying the concept of molecular overlap ratio along the long/short axis, we could show that the effective π-stacking area dominantly determines the field-effect mobility of π-stacked materials. In the case of TIPSAntNa, a large π-stacking area and a small π-stacking distance enabled the highest field-effect mobility.