The role of the side chain on the performance of N-type conjugated polymers in aqueous electrolytes
byA. Giovannitti, I.P. Maria, D. Hanifi, M.J. Donahue, (...), O.G. Reid, S. Inal, G. Rumbles, G.G. Malliaras, J. Nelson, J. Rivnay, I. McCulloch
The role of the side chain on the performance of N-type conjugated polymers in aqueous electrolytes A. Giovannitti, I.P. Maria, D. Hanifi, M.J. Donahue, (...), S. Inal, G. Rumbles, G.G. Malliaras, J. Nelson, J. Rivnay, I. McCulloch Chemistry of Materials 30 (9), 2945-2953, 2018
We report a design strategy that allows the preparation of solution processable n-type materials from low boiling point solvents for organic electrochemical transistors (OECTs). The polymer backbone is based on NDI-T2 copolymers where a branched alkyl side chain is gradually exchanged for a linear ethylene glycol-based side chain. A series of random copolymers was prepared with glycol side chain percentages of 0, 10, 25, 50, 75, 90, and 100 with respect to the alkyl side chains. These were characterized to study the influence of the polar side chains on interaction with aqueous electrolytes, their electrochemical redox reactions, and performance in OECTs when operated in aqueous electrolytes. We observed that glycol side chain percentages of >50% are required to achieve volumetric charging, while lower glycol chain percentages show a mixed operation with high required voltages to allow for bulk charging of the organic semiconductor. A strong dependence of the electron mobility on the fraction of glycol chains was found for copolymers based on NDI-T2, with a significant drop as alkyl side chains are replaced by glycol side chains.
Conjugated polymersElectrolytesAqueous electrolytePolar side chainsPolymer backbones
"KAUST shall be a beacon for peace, hope and reconciliation, and shall serve the people of the Kingdom and the world."
King Abdullah bin Abdulaziz Al Saud, 1924 – 2015
4700 King Abdullah University of Science and Technology