Carrier range on finite, isolated molecular wires in a monomer crystallinematrix - Example: polydiacetylene, 4BCMU

Photoconductive properties of isolated polydiacetylene 4BCMU chains in a di acetylene monomer matrix are studied using a charge collection technique af ter pulsed UV irradiation. These new results show that in partially polymer ised diacetylene crystals, the carriers travel distances approximately prop ortional to the degree of polymerisation and substantially greater than the length of the individual, electronically isolated, chains. Mechanisms wher eby this unusual property may come about are discussed including interchain tunnelling, Coulomb glass formation and non-random filamentary polymerisat ion resulting in an extended collection of chains growing preferentially en d to end after some initially random chain initiation events. (C) 1999 Else vier Science B.V. All rights reserved.