Photoconductivity of the ladder polymer BBL

The absorption and photoconduction properties of the ladderpolymer polybenzimidazo-benzoisoquinoline, BBL, are studied. The steady-state photoconductivity was measured as a function of photon energy, electric field, temperature, and chopper frequency. The photocurrent response as a function of energy precedes the absorption and shows a broad tail round the band edge in contrast to the sharp absorption edge near 1.68 eV