Photoelectrochemistry with polymer electrodes : poly (primulin- and toluidine blue-O) acetylene

Abstract

The objectives of this research are twofold: the synthesis of two polyacetylene-ionic dye polymers and subsequent experimentation on their semiconductive and photoelectric properties. The synthetic approach of chemically coupling a poly (acetylene) backbone (the conducting portion of the molecule) to the light absorbing moiety (the organic-ionic dye), has not, until now, been experimentally shown.

The chemical route was to couple an acetylene-carboxylic acid with an amine function on the ionic dye forming an amide linkage. Verification of the presence of both the amide linkage and the polymerization of the triple bond came primarily from infrared and nuclear magnetic resonance spectroscopy.

The semiconductive properties of these polymers were tested utilizing cyclic voltammetry. Photoconduction was ascertained by the same process using also a 1000 watt ultraviolet source for photoexcitation of the polymer. One potential use of this system is to split water into hydrogen and oxygen. By using both cationic and anionic dyes, n- and p- type semiconducting polymers were prepared. As photochemical diode materials, these polymers, when simultaneously illuminated and ohmically connected, may in principle photo-catalyze the decomposition of water.