Electrical properties of polyunsaturated natural products: field effect mobility of carotenoid polyenes

Carotenoids are polyacetylene-like natural products with substituents that enhance stability, solubility, and processing. Measurements on a set of five carotenoids show bixin and beta-carotene to be active as field effect semiconductors, with p-type mobilities in the range of 10(-6) to 10(-7) cm(2)/V s. The structural characteristics responsible for distinguishing between active and inactive compounds are not apparent at this time. However, biosynthetic means of making carotenoids may make available a large number of carotenoids, both natural and unnatural, suggesting that carotenoids could be a rich source of different field effect semiconductors. (C) 2004 Elsevier B.V. All rights reserved.