Low bandgap Poly(Thienylene Vinylene) for Organic Solar Cells: Photophysics and Photovoltaic Performance

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 C61 – 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 2 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.