Studies on electrical transport properties of a novel n-type polymer containing tripylborane and fluorene moieties

An organoboron polymer, poly[(2,4,6-triisopropylphenyl)borylenevinylene-2,7-fluorenylenevinylene], has been synthesized by hydro-boration polymerization with 2,4,6-triisopropylphenylborane and 2,7-diethynylfluorene. The polymer is π-electron deficient due to boron atom contained in its main-chain and the π-conjugation length in it is extended via the vacant p-orbital of the boron atom. It has been found that the polymer shows an electrical conductivity of about 10−6 Scm−1 by n-doping with triethylamine at RT. By continuous photo-excitation of ITO-Polymer-Au cells, it has been proved that the polymer is an n-type conductor. In addition, by pulsed photo-excitation of the cell, it has been verified that the drift mobility of electron is about five times higher than that of hole. The n-type electrical transport properties of the polymer have been also associated with an anodic wave that appears at about −1.17 V in cyclic voltammograms and is ascribable to n-doping.