Materials chemistry communications. Electrochemical doping of α-ethyl-disubstituted oligothiophenes and electrical conductivities of the resulting radical-cation salts

Abstract

Electrochemical doping of α-ethyl-disubstituted oligothiophenes and the electrical conductivity of the resulting radical-cation salts have been studied. 5,5‴-Diethyl-2,2′:5′,2″:5″,2‴-quaterthiophene (DEt4T) and 5,5â�—-diethyl-2,2′:5′,2″:5″,2‴:5‴,2â�—-quinquethiophene (DEt5T) are found to contrast with each other in the stoichiometry and electrical properties of the resulting solid radical-cation salts. The DEt4T and DEt5T radical-cation salts with a doping extent of ca. 100 and 50%, respectively, produced by electrochemical doping exhibited room-temperature conductivities of 9 × 10^–8 and 5 × 10^–3 S cm^–1 with activation energies of 0.54 and 0.11 eV, respectively.