PHYSICAL VAPOR GROWTH OF ORGANIC SEMICONDUCTORS

Physical vapor growth in horizontal and vertical systems has been used to grow crystals of a-hexathiophene (alpha-6T), alpha-octithiophene ( alpha-8T), alpha-quaterthiophene (alpha-4T), pentacene, anthracene and copper phthalocyanine. Using 10-30 mg of starting material, mm-cm siz ed crystals, suitable for characterization measurements, have been gro wn. New polymorphs of alpha-quaterthiophene (high temperature, HT and low temperature, LT) and pentacene were discovered. A horizontal geome try is shown to be advantageous because the fragile crystals are extra cted more easily. (C) 1998 Elsevier Science B.V. All rights reserved.