Methodologies for the synthesis of pentacene and its derivatives

In recent years, due to its high hole-mobility, high on/off current ratio and low threshold voltage, pentacene and its derivatives have found increasing application in the fabrication of light-emitting diodes, field-effect transistors and photovoltaic cells. It has also emerged as an alternative to silicon due to its similar performance to inorganic semiconductors. Pentacene cannot be isolated from the petroleum fractions like other acenes such as anthracene or tetracene, and therefore it needs to be chemically synthesized. The first successful synthesis of pentacene was reported in early 19th century where pentacene was obtained via dehydrogenation of 6,14-dihydropentacene. Since then a number of methods have been reported for the synthesis of pentacene. This review describes various strategies used for the synthesis of pentacene and its derivatives reported since 2005.