Photophysical studies and photovoltaic devices on a low bandgap, high charge-carrier-mobility Poly(Thienylene
Vinylene) (PTV), prepared from a soluble precursor polymer synthesised via the 'dithiocarbamate route', are reported.
In composites with an electron acceptor ([6,6]-phenyl C<sub>61</sub>- butyric acid methyl ester (PCBM), a soluble fullerene
derivative) photoinduced absorption (PIA) characteristic for charged excitations together with photoluminescence (PL)
quenching are observed indicating photoinduced electron transfer. The "bulk heterojunction" photovoltaic devices using
PTV and PCBM composites show short circuit currents up to 4 mA/cm<sup>2</sup> under AM 1.5 white-light illumination. The
photocurrent spectrum of the photovoltaic device shows an onset at about 1.65 eV (750 nm) which corresponds to the
absorption spectrum of the polymer.