Photoconductivity of substituted polyacetylenes

photoconduction under visible light illumination is investigated using xero graphic discharge technique in the photoreceptors of the following substitu ted polyacetylenes: -[HC=C(C6H5-p-R)](n)-, -[HC=C(3-C4H2S-beta -R')](n)-, a nd -{HC=C[(CH2)(m)-R"]}(n)-, where p = CH3 (2), CO2(CH3)(3) (4), Br (5); an d R" = CO2(CH2)(6)OCO-Biph-OC9H19 (m = 2; 6), 9-carbazolyl (m =3; 7), OCO-B iph-OC9H15 (m = 9; 8), In the undoped state, 2-4 and 6-8 show much higher p hotosensitivity than poly(phenylacetylene)(R = H; 1). The polyacetylenes wi th electron-donating and/or hole-transporting substituents perform better t han do those with electron-accepting ones. The liquid crystalline polyacety lene 6 exhibits very high photosensitivity, probably because of the crystal line aggregates of its mesogenic pendants. C-60 acts as a photoconductivity enhancer when doped to amorphous 3 but functions as a quencher when mixed with liquid crystalline 6. While 3 shows low photosensitivity in the undope d state, doping with I-2 and sensitization with crystal violet dramatically increase its photosensitivity up to 41.2 x 10(-3) lx(-1) sec(-1). Copyrigh t (C) 2000 Society of Chemical Industry.