Visible Light Photoconduction of Poly(disilanyleneoligothienylene)s and Doping Effect of C60

The photoconductive properties of poly(disilanyleneoligothienylene)s [PDS(Th) m; m = 2−4], which have a disilanylene group and an oligothienylene unit in a polymer backbone, and fullerene (C 60 ) doping effects were investigated. It was found that these polymers are photoconductive and have photocarrier generation maxima in accordance with their optical absorption spectra. The polymer PDS(Th) 4 was photoconducting when irradiated in the visible light and the quantum efficiency for photocarrier generation was 2% at 480 nm ( E = 6 × 10 5 V cm -1 ). The hole-drift mobility was measured and ranged between 1.1 × 10 -4 cm 2 V -1 s -1 at 2 × 10 5 V cm -1 and 2.1 × 10 -4 cm 2 V -1 s -1 at 6 × 10 5 V cm -1 at room temperature. As far as we know, this is the first observation of photocarrier generation in the visible region in silicon-based polymers. Furthermore, C 60 doping enhanced the photoconductivity quantum efficiency effectively to 85% at 470 nm ( E = 3 × 10 5 V cm -1 ) by a photoinduced charge transfer mechanism.