Carrier range on conjugated polymers as molecular wires. Example: polydiacetylene, 4BCMU Original Research Article

The crystalline polydiacetylene 4BCMU is studied using a photocharge collection technique following a 6 ns pulse of UV irradiation. From these studies it is shown, by two separate routes, that with blocking electrodes the single crystal polydiacetylene is a unity gain photoconductor. This entails that the distance of travel of a photocarrier on the polymer backbone of 100% polydiacetylene single crystals is much greater than the 2.5 μm length of the individual polymer chains that form the crystal and equal to the crystal length of up to several millimetres. Furthermore this knowledge of the photocarrier range enables the absolute determination of the photocarrier generation efficiency. Such information is crucial to the interpretation of other photoconduction experiments.