Polymeric compositions having near IR photoconduction

Abstract

Peculiar properties of carrier photogeneration in the polymer compositions based on polystyrene containing substituted tetrathiafulvalenes – electron donors, 2,4,5,7-tetranitro-9-fluorenone – acceptor of electrons, cationic polymethine dye – tetrafluoroborate 1,3,3-trimethy 1-2-[3-(1,3-dihydro-1,3,3-trimethyl-2I-2-indolyliden)-1-propenyl]-3I-indolium and neutral merocyanine - 5-[6-(1,3-dihydro[1,3,3-trimethyl-2I-indol-2-yliden)-4-phenyl-3,5-(ethylene)-hexa-2,4,6-trien-1-yl] thiobarbituric acid – sensitizers. The photoconductivity in the dye absorption range increases, when the cation dye changed to the neutral, mostly due to mobile carrier with both charges sign photogeneration, and the activation energy of the photoconductivity current decrease. The decrease of photoconduction current activation energy can be related to the organic charged counterion generation in the neutral dye case, and the uncoloured counterion retains more strongly the opposite charge on the photogenerated organic ion in the cation dye case.