Phenacene

Phenacenes are a class of organic compounds consisting of fused aromatic rings. They are polycyclic aromatic hydrocarbons, related to acenes and helicenes from which they differ by the arrangement of the fused rings.

[n]Phenacene	Common name	Structure
[4]phenacene	Chrysene
[5]phenacene	Picene
[6]phenacene	Fulminene
[7]phenacene

Relevance to organic electronic materials

Aromatic compounds with extended π-conjugated system have attracted attention because of their potential use in organic electronics as organic semiconductors.^[1] Of academic interest, pentacene has been widely used as an active layer in organic thin-film field-effect transistors (OFET). The main drawback of pentacene OFET is degradation upon exposure to light and air. On the other hand, [n]phenacenes, an isomeric form of [n]acenes, has been known as a stable compound in which the benzene rings are fused in a zigzag structure. For the past several years, there is renewed interest in synthesis of [n]phenacene derivatives associated with electronic applications in emissive and semi- or superconducting materials.^[2][3][4]

Picene ([5]phenacene) can serve as an active layer of a high-performance p-channel organic thin-film FET with very high field-effect mobility μ = 5 cm²/(V⋅s).^[5] [7]Phenacene FET shows μ = 0.75 cm²/(V⋅s) and no sensitivity to air. Furthermore, picene doped with potassium and rubidium exhibit superconductivity with a maximum critical temperature T_C ≈ 18 K.^[4] Thus, [n]phenacenes and their derivatives may play an important role in future fabrication of stable and high-performance electronic devices such as OFET, OLED and organic solar cells. Substituted picenes may serve as an active layer of OFETs.^[6]