Bipolar redox behaviour, field-effect mobility and transistor switching of the low-molecular azo glass AZOPD

Abstract

We present electrochemical and spectroelectrochemical data for the bipolar azo compound N,N′-diphenyl-N,N′-bis[4-(phenylazo)phenyl]-4,4′diaminobiphenyl (AZOPD) demonstrating reversible bipolar redox behaviour with a bandgap of 2.1 eV. The reduced species formed upon two-electron transfer can be described as bis(radical anion) as was confirmed by comparison with a reference compound with only one azo chromophore. Hole and electron transport behaviour in amorphous films was demonstrated by the fabrication of organic field-effect transistors using gold and magnesium contacts, respectively. The transistors are sensitive to light due to E–Z photoisomerization.