Conducting thin films of pentacene doped with alkaline metals

Donor doping of thin films of pentacene (PEN) with alkaline metals such as sodium, potassium, and rubidium was carried out. Drastic changes in conductivities of PEN films from an insulator to an n-type semiconductor due to the doping was observed. Maximum conductivity of 2.8 Ω−1 cm−1 was shown in the film doped with rubidium. Alkaline metal doping of thin films of other acene compounds such as tetracene and hexacene was also performed.