The past decade has witnessed tremendous advances in
the development of organic conductive molecular and
polymeric materials and this field continues to be of
great scientific and commercial interest. This field of
science flourished on discovering new ^-conjugated
materials and by tailoring their electrical conductivity
from semiconductive to metallic to a superconductive
regime when doped. The term 'Synthetic Metals'
therefore originated from this theme. The first
category of organic conductive and superconductive
molecules are based on charge-transfer salts where
BEDT-TTF [bis(ethylenedithio)tetrathiafulvalene],
M(dmit)2 (dmit= l,3-dithio-2-thione-4,5-dithiolate),
DCNQI (AyV'-dicyano-p-quinonediimine), perylene,
tetrachalcogenafulvalenes and their structurally related
analogs are just a few of the most commonly studied in
the past decade. Fullerenes constitute another class
which also exhibit superconductivity when doped with
alkali metals. Research activities are being carried out
around the world to produce pure fullerenes (C60, C70,
C76, C78, C82, C84, C90, and higher fullerenes) and to
prepare their derivatives as well as polymers. Interestingly
the 1996 Nobel Prize for Chemistry was awarded
to the research team who discovered fullerenes in 1985.
Attempts continue in both charge-transfer salts and
fullerenes to develop new superconductive materials
with a record-high transition temperature. In 1977, a
team led by A. J. Heeger, A. G. MacDiarmid and
H. Shirakawa demonstrated that the electrical conductivity
of polyacetylene can be increased by 13 orders of
magnitude upon doping with electron acceptors and
electron-donors, which created virtually the new field
of conducting polymers. Achieving conductivity as
high as that of copper metal in polyacetylene by
H. Naarmann and coworkers, was a milestone discovery.
Inspired by polyacetylenes, new conductive
polymers such as poly-thiophene, polypyrrole, poly(p-phenylene),
poly(/?-phenylene sulphide) and polyaniline
were also developed since 1978.