A Xanthene Polymer with Semiconducting Properties

Abstract

A series of xanthene polymers has been prepared as the first stage of a study of the potentialities of organic semiconductors for the synthesis of model enzymes, and for the development of ion-exchange adsorbents capable of direct electrical regeneration. The polymer is composed of condensed xanthene residues cross-linked with phenyl bridges. The polymers are p-type semiconductors and the best has a specific resistance of 7 x 10³ Ω cm which is less than that of crystalline organic semiconductors by a factor of at least 10⁴. The conductivity is not due to the diradicals of the quinonoid resonance form of quinolphthalein, but is more probably due to a resonating carbonium cation arising from partial ionization of the xanthylium-lactone bond. The effect of polymerization conditions on the resistance of the polymer has been studied.