Pentacene is a polycyclic aromatic hydrocarbon consisting of 5 linearly-fused benzene rings. This extended conjugation, together with a favorable crystal structure is responsible for its properties as an organic semiconductor. The purple-colored compound generates excitons upon absorption of ultra-violet or visible light; making it sensitive to oxidation. For this reason, its originally purple color in the solid state slowly turns green upon prolonged exposure to air and light.
Source: Wikipedia
URL: http://en.wikipedia.org/wiki/Pentacene
Source: Wikipedia
URL: http://en.wikipedia.org/wiki/Pentacene
