Phenacenes are a class of
organic compound
In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. The ...
s consisting of fused aromatic rings. They are
polycyclic aromatic hydrocarbon
A polycyclic aromatic hydrocarbon (PAH) is a class of organic compounds that is composed of multiple aromatic rings. The simplest representative is naphthalene, having two aromatic rings and the three-ring compounds anthracene and phenanthrene. ...
s, related to
acene
In organic chemistry, the acenes or polyacenes are a class of organic compounds and polycyclic aromatic hydrocarbons made up of benzene () rings which have been linearly fused. They follow the general molecular formula .
The larger representa ...
s and
helicene
In organic chemistry, helicenes are ortho-condensed polycyclic aromatic compounds in which benzene rings or other aromatics are angularly annulated to give helically-shaped chiral molecules. The chemistry of helicenes has attracted continuing ...
s from which they differ by the arrangement of the fused rings.
Relevance to organic electronic materials
Aromatic compounds with extended π-conjugated system have attracted attention because of their potential utilization in
organic electronics
Organic electronics is a field of materials science concerning the design, synthesis, characterization, and application of organic molecules or polymers that show desirable electronic properties such as conductivity. Unlike conventional inorga ...
as
organic semiconductor
Organic semiconductors are solids whose building blocks are pi-bonded molecules or polymers made up by carbon and hydrogen atoms and – at times – heteroatoms such as nitrogen, sulfur and oxygen. They exist in the form of molecular crystals or ...
s.
Of academic interest, pentacene has been widely used as an active layer in organic thin film field effect transistors (
OFET
An organic field-effect transistor (OFET) is a field-effect transistor using an organic semiconductor in its channel. OFETs can be prepared either by vacuum evaporation of small molecules, by solution-casting of polymers or small molecules, or ...
). The main drawback of pentacene OFET is degradation upon exposure to light and air. On the other hand,
henacenes, an isomeric form of
cenes, 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
henacene derivatives associated with electronic applications in emissive and semi- or superconducting materials.
Picene
Picene is a hydrocarbon found in the pitchy residue obtained in the distillation of peat tar and of petroleum. This is distilled to dryness and the distillate repeatedly recrystallized from cymene. It may be synthetically prepared by the action ...
(
henacene) can serve as an active layer of a high performance p-channel organic thin film FET with very high field-effect mobility: μ of 5 cm
2∙V
−1∙s
−1.
henacene FET shows effect mobility μ of 0.75 cm
2∙V
−1∙s
−1 and no sensitivity to air. Furthermore, picene doped with potassium and rubidium exhibit
superconductivity
Superconductivity is a set of physical properties observed in certain materials where electrical resistance vanishes and magnetic flux fields are expelled from the material. Any material exhibiting these properties is a superconductor. Unlike ...
with a maximum critical temperature 𝑇𝑐∼18 K.
Thus,
henacenes and their derivatives may play an important role in future fabrication of stable and high-performance electronic devices such as OFET,
OLED
An organic light-emitting diode (OLED or organic LED), also known as organic electroluminescent (organic EL) diode, is a light-emitting diode (LED) in which the emissive electroluminescent layer is a film of organic compound that emits light i ...
and
organic solar cells
An organic solar cell (OSC) or plastic solar cell is a type of photovoltaic that uses organic electronics, a branch of electronics that deals with conductive organic polymers or small organic molecules, for light absorption and charge transport t ...
. Substituted picenes may serve as an active layer of OFETs.
[Nakano, Y.; Saito, M.; Nakamura, H. WO 2010016511 A1 20100211, 2010.]
References
{{PAHs
Polycyclic aromatic hydrocarbons