Bistetracene: An Air-Stable, High-Mobility Organic Semiconductor with Extended Conjugation

We report the synthesis
and characterization of “bistetracene”,
an unconventional, linearly extended conjugated core with eight fused
rings. The annellation mode of the system allows for increased stability
of the conjugated system relative to linear analogues due to the increased
number of Clar aromatic sextets. By attaching the appropriate solubilizing
substituents, efficient molecular packing with large transfer integrals
can be obtained. The electronic structure calculations suggest these
large polycyclic aromatic hydrocarbons (PAHs) exhibit excellent intrinsic
charge transport properties. Charge carrier mobilities as large as
6.1 cm2 V–1 s–1 and
current on/off ratios of 107 were determined experimentally
for one of our compounds. Our study provides valuable insight into
the design of unconventional semiconductor compounds based on higher
PAHs for use in high-performance devices.